Power generation system

Abstract
A process for generating electricity in which a gas/liquid mixture is compressed in a compressor, partially purified in an accumulator/separator, partially purified in a coalescent filter, subjected to pressure regulation, and then fed to a microturbine. The microturbine produces a direct current which is used to drive a direct current motor which, in turn, drives a generator which produces alternating current.
Description




FIELD OF THE INVENTION




A power generation system for generating electricity in which a compressor, a pump, and a prime mover are operatively connected to each other.




BACKGROUND OF THE INVENTION




Microturbines, also known as turbogenerators and turboalternators, are gaining increasing popularity and acceptance. These microturbines are often used in conjunction with one or more compressors which supply gaseous fuel to them at a desired pressure, generally from about 40 to about 500 pounds per square inch.




The microturbines are often employed in a system comprising two or more microturbines. These systems could be supplied by only one compressor, but such operation often results in too much compressor capacity when less than all of the microturbines are operating.




It is an object of this invention to provide a process for controlling the output of a multiplicity of compressors connected to one or more microturbines.




SUMMARY OF THE INVENTION




A power generation system comprised of a guided rotor compressor, a liquid injection metering pump operatively connected to such compressor, and a prime mover to which the output of the compressor is fed.











BRIEF DESCRIPTION OF THE DRAWINGS




The claimed invention will be described by reference to the specification and the following drawings, in which:





FIG. 1

is a perspective view of one preferred rotary mechanism claimed in U.S. Pat. No. 5,431,551;





FIG. 2

is an axial, cross-sectional view of the mechanism of

FIG. 1

;





FIG. 3

is a perspective view of the eccentric crank of the mechanism of

FIG. 1

;





FIG. 4A

is a transverse, cross-sectional view of the eccentric crank of

FIG. 3

;





FIG. 5

is a perspective view of the rotor of the device of

FIG. 1

;





FIG. 6

is an axial, cross-sectional view of the rotor of

FIG. 5

;





FIG. 7

is a transverse, cross-sectional view of the rotor of

FIG. 5

;





FIG. 8

is an exploded, perspective view of the device of

FIG. 1

;





FIG. 9

is a sectional view of one hollow roller which can be used in the rotary positive displacement device of this invention;





FIG. 10

is a sectional view of another hollow roller which can be used in the rotary positive displacement device of this invention;





FIG. 11

is a schematic view of a modified rotor which can be used in the positive displacement device of this invention;





FIG. 12

is a block diagram of a preferred electrical generation system;





FIG. 13

is a block diagram of the gas booster system of

FIG. 12

;





FIG. 14

is a schematic representation of an apparatus comprised of a guided rotor device and a reciprocating compressor;





FIG. 15

is a schematic representation of another apparatus comprised of a guided rotor device and a reciprocating compressor;





FIG. 16

is a schematic representation of another guided rotor apparatus; and





FIG. 17

is a schematic representation of yet another guided rotor apparatus;





FIG. 18

is a sectional view of a multi-stage guided rotor assembly;





FIG. 19

is a sectional view of a guided rotor assembly with its drive motor enclosed within a hermetic system;





FIG. 20

is a schematic illustration of a microturbine electric generation and waste heat recovery system;





FIG. 21

is a schematic diagram of one preferred process of the invention, illustrating one preferred means for measuring gas pressure within the electrical generating system;





FIG. 22

is a schematic diagram of the process depicted in

FIG. 21

, illustrating a preferred a preferred pressure relief system;





FIG. 23

is a graph illustrating the typical history of gas pressure versus time for the system of

FIG. 21

;





FIG. 24

is an exploded view of one preferred rotary mechanism of the invention;





FIG. 25

is a partial sectional view of the mechanism of

FIG. 24

, illustrating the interaction between the rotor and external gear on the side plate of the housing;





FIG. 26

is a schematic representation of a troichoidal surface and an envoluted trochoidal surface produced by the device of this invention;





FIGS. 27

,


28


,


29


,


30


, and


31


are schematic representations of a rotor with a solid curved surface, a strip seal, a spring-loaded seal, and a strip of material, as well as all of these structures, disposed at one or more of its apices for sealing purposes;





FIG. 32

is a schematic representation of a process for generating electricity from landfill gas;





FIG. 33

is a schematic representation of another process for generating electricity from digester gas;





FIG. 34

is a sectional view of the separator used in the process of

FIGS. 32 and 33

;





FIG. 35

is a top view of the separator of

FIG. 34

;





FIG. 36

is a front view of the cone on the separator of

FIG. 34

;





FIG. 37

is a front view of the vent on the separator of

FIG. 34

;





FIG. 38

is partial top view of the perforated plate on the separator of

FIG. 34

;





FIG. 39

is a schematic diagram of a separation system for purifying gas;





FIG. 40

is a schematic of an electricity generation system packaged on an open skid;





FIG. 41

is a schematic of electricity generation system packaged in a modular fashion;





FIG. 42

is a schematic of an electricity generation system disposed within a concrete enclosure;





FIGS. 43A and 43B

illustrate a sound attenuation device operatively connected to a microturbine;





FIG. 44

is a schematic of a power generation system containing a prime mover, a compressor, and metering pump;





FIGS. 45A

,


45


B,


45


C, and


45


D are schematic of different pump/compressor assemblies;





FIG. 46A

is a sectional view of a novel compressor;





FIG. 46B

is a top view of the rotor of the compressor of

FIG. 46A

;





FIG. 46C

is a side view of the suction side stator of the compressor of

FIG. 46A

;





FIG. 46D

is a side view of an intermediate stator of the compressor of

FIG. 46A

;





FIG. 46E

is a side view of the discharge side stator of the compressor of

FIG. 46A

;




and





FIGS. 47A

,


47


B, and


47


C are schematics of novel power generation systems.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




In the first part of this specification, applicants will describe a system for generating electricity. In the second part of this specification, applicants will describe a system for controlling the amount of gas delivered in an electrical generating system comprised of two or more microturbines. In the third part of this specification, applicants will describe several novel compressor assemblies.





FIGS. 1

,


2


,


3


,


4


,


4


A,


5


,


6


,


7


, and


8


are identical to the

FIGS. 1

,


2


,


3


,


4


,


4


A,


5


,


6


,


7


, and


8


appearing in U.S. Pat. No. 5,431,551; and they are presented in this case to illustrate the similarities and differences between the rotary positive displacement device of such patent and the rotary positive displacement device of the instant application. The entire disclosure, the drawings, the claims, and the abstract of U.S. Pat. No. 5,431,551 are hereby incorporated by reference into this specification.




Referring to

FIGS. 1 through 8

, and to the embodiment depicted therein, it will be noted that rollers


18


,


20


,


22


, and


24


(see

FIGS. 1 and 8

) are solid. In the rotary positive displacement device of the instant invention, however, the rollers used are hollow.





FIG. 9

is a sectional view of a hollow roller


100


which may be used to replace the rollers


18


,


20


,


22


, and


24


of the device of

FIGS. 1 through 8

. In the preferred embodiment depicted, it will be seen that roller


100


is a hollow cylindricral tube


102


with ends


104


and


106


.




Tube


102


may consist of metallic and/or non-metallic material, such as aluminum, bronze, polyethyletherketone, reinforced plastic, and the like. The hollow portion


108


of tube


102


has a diameter


110


which is at least about 50 percent of the outer diameter


112


of tube


102


.




The presence of ends


106


and


108


prevents the passage of gas from a low pressure region (not shown) to a high pressure region (not shown). These ends may be attached to tube


102


by conventional means, such as adhesive means, friction means, fasteners, threading, etc.




In the preferred embodiment depicted, the ends


106


and


108


are aligned with the ends


114


and


116


of tube


102


. In another embodiment, either or both of such ends


106


and


108


are not so aligned.




In one embodiment, the ends


106


and


108


consist essentially of the same material from which tube


102


is made. In another embodiment, different materials are present in either or both of ends


106


and


108


, and tube


102


.




In one embodiment, one of ends


106


and/or


108


is more resistant to wear than another one of such ends, and/or is more elastic.





FIG. 10

is sectional view of another preferred hollow roller


130


, which is comprised of a hollow cylindrical tube


132


, end


134


, end


136


, resilient means


138


, and O-rings


140


and


142


. In this embodiment, a spring


138


is disposed between and contiguous with ends


134


and


136


, urging such ends in the directions of arrows


144


and


146


, respectively. It will be appreciated that these spring-loaded ends tend to minimize the clearance between roller


130


and the housing in which it is disposed; and the O-rings


140


and


142


tend to prevent gas and/or liquid from entering the hollow center section


150


.




In the preferred embodiment depicted, the ends


144


and


146


are aligned with the ends


152


and


154


of tube


132


. In another embodiment, not shown, one or both of ends


144


and/or


146


are not so aligned.




The resilient means


138


may be, e.g., a coil spring, a flat spring, and/or any other suitable resilient biasing means.





FIG. 11

is a schematic view of a rotor


200


which may be used in place of the rotor


16


depicted in

FIGS. 1

,


5


,


6


,


7


, and


8


. Referring to

FIG. 11

, partial bores


202


,


204


,


206


, and


208


are similar in function, to at least some extent, the partial bores


61


,


63


,


65


, and


67


depicted in

FIGS. 5

,


6


,


7


, and


8


. Although, in

FIG. 11

, a different partial bore has been depicted for elements


202


,


204


,


206


, and


208


, it will be appreciated that this has been done primarily for the sake of simplicity of representation and that, in most instances, each of partial bores


61


,


63


,


65


, and


67


will be substantially identical to each other.




It will also be appreciated that the partial bores


202


,


204


,


206


, and


208


are adapted to be substantially compliant to the forces and loads exerted upon the rollers (not shown) disposed within said partial bores and, additionally, to exert an outwardly extending force upon each of said rollers (not shown) to reduce the clearances between them and the housing (not shown).




Referring to

FIG. 11

, partial bore


202


is comprised of a ribbon spring


210


removably attached to rotor


16


at points


212


and


214


. Because of such attachment, ribbon spring


210


neither rotates nor slips during use. The ribbon spring


210


may be metallic or non-metallic.




In one embodiment, depicted in

FIG. 11

, the ribbon spring


210


extends over an arc greater than 90 degrees, thereby allowing it to accept loads at points which are far from centerline


216


.




Partial bore


204


is comprised of a bent spring


220


which is affixed at ends


222


and


224


and provides substantially the same function as ribbon spring


210


. However, because bent spring extends over an arc less than 90 degrees, it accepts loads primarily at our around centerline


226


.




Partial bore


206


is comprised of a cavity


230


in which is disposed bent spring


232


and insert


234


which contains partial bore


206


. It will be apparent that the roller disposed within bore


206


(and also within bores


202


and


204


) are trapped by the shape of the bore and, thus, in spite of any outwardly extending resilient forces, cannot be forced out of the partial bore. In another embodiment, not shown, the partial bores


202


,


204


,


206


, and


208


do not extend beyond the point that rollers are entrapped, and thus the rollers are free to partially or completely extend beyond the partial bores.




Referring again to

FIG. 11

, it will be seen that partial bore


208


is comprised of a ribbon spring


250


which is similar to ribbon spring


210


but has a slightly different shape in that it is disposed within a cavity


252


behind a removable cradle


254


. As will be apparent, the spring


250


urges the cradle


254


outwardly along axis


226


. Inasmuch as the spring


250


extends more than about 90 degrees, it also allows force vectors near ends


256


and


258


, which, in the embodiment depicted, are also attachment points for the spring


250


.





FIG. 12

is a block diagram of one preferred apparatus of the invention. Referring to

FIG. 12

, it will be seen that gas (not shown) is preferably passed via gas line


310


to gas booster


312


in which it is compressed to a pressure required by micro turbine generator


314


. In general, the gas must be compressed to a pressure in excess of 30 p.s.i.g., although pressures as low as about 20 p.s.i.g. and as high as 360 p.s.i.g. or more also may be used.




In

FIGS. 12 and 13

, a micro turbine generator


314


is shown as the preferred receiver of the gas via line


313


. In other embodiments, not shown, a larger gas turbine and/or a fuel cell may be substituted for the micro turbine generator


314


.




In one embodiment, in addition to increasing the pressure of the natural gas, the gas booster


312


also generally increases its temperature to a temperature within the range of from about 100 to about 150 degrees Fahrenheit. In one embodiment, the gas booster


312


increases the temperature of the natural gas from pipeline temperature to a temperature of from about 100 to about 120 degrees Fahrenheit.




The compressed gas from gas booster


312


is then fed via line


313


to micro turbine generator


314


. The components used in gas booster


312


and in micro turbine generator


314


will now be described.





FIG. 13

is a schematic diagram of the gas booster system


312


of FIG.


12


. Referring to

FIG. 12

, it will be seen that gas booster system


312


preferably is comprised of a guided rotor compressor


316


.




The guided rotor compressor


316


depicted in

FIG. 13

is substantially identical to the guided rotor compressor


10


disclosed in U.S. Pat. No. 5,431,551, the entire disclosure of which is hereby incorporated by reference into this patent application. This guided rotor compressor is preferably comprised of a housing comprising a curved inner surface with a profile equidistant from a trochoidal curve, an eccentric mounted on a shaft disposed within said housing, a first rotor mounted on said eccentric shaft which is comprised of a first side, a second side, and a third side, a first partial bore disposed at the intersection of said first side and said second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first solid roller disposed and rotatably mounted within said first partial bore, a second solid roller disposed and rotatably mounted within said second partial bore, and a third solid roller disposed and rotatably mounted within said third partial bore.




The rotor is comprised of a front face, a back face, said first side, said second side, and said third side. A first opening is formed between and communicates between said front face and said first side, a second opening is formed between and communicates between said back face and said first side, wherein each of said first opening and said second opening is substantially equidistant and symmetrical between said first partial bore and said second partial bore. A third opening is formed between and communicates between said front face and said second side. A fourth opening is formed between and communicates between said back face and said second side, wherein each of said third opening and said fourth opening is substantially equidistant and symmetrical between said second partial bore and said third partial bore. A fifth opening is formed between and communicates between said front face and said third side. A sixth opening is formed between and communicates between said back face and said third side, wherein each of said fifth opening and said sixth opening is substantially equidistant and symmetrical between said third partial bore and said first partial bore.




Each of said first partial bore, said second partial bore, and said third partial bore is comprised of a centerpoint which, as said rotary device rotates, moves along said trochoidal curve.




Each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening has a substantially U-shaped cross-sectional shape defined by a first linear side, a second linear side, and an arcuate section joining said first linear side and said second linear side. The first linear side and the second linear side are disposed with respect to each other at an angle of less than ninety degrees; and said substantially U-shaped cross-sectional shape has a depth which is at least equal to its width.




The diameter of said first roller is equal to the diameter of said second solid roller, and the diameter of said second solid roller is equal to the diameter of said third solid roller.




The widths of each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening are substantially the same, and the width of each of said openings is less than the diameter of said first solid roller.




Each of said first side, said second side, and said third side has substantially the same geometry and size and is a composite shape comprised of a first section and a second section, wherein said first section has a shape which is different from that of said second section.




The aforementioned compressor is a very preferred embodiment of the rotary positive displacement compressor which may be used as compressor


316


; it is substantially smaller, more reliable, more durable, and quieter than prior art compressors. However, one may use other rotary positive displacement compressors such as, e.g., one or more of the compressors described in U.S. Pat. Nos. 5,605,124, 5,597,287, 5,537,974, 5,522,356, 5,489,199, 5,459,358, 5,410,998, 5,063,750, 4,531,899, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




In one preferred embodiment, the rotary positive displacement compressor used as compressor


316


is a Guided Rotor Compressor which is sold by the Combined Heat and Power, Inc. of 210 Pennsylvania Avenue, East Aurora, N.Y.




Referring again to

FIG. 13

, it will be seen that the compressed gas from compressor


316


is fed via line


313


to micro turbine generator


314


. As is disclosed in U.S. Pat. No. 5,819,524 (see, e.g., claim


1


thereof), such micro turbine generator


314


is a turbogenerator set including a turbogenerator power controller, wherein said turbogenerator also includes a compressor, a turbine, a combustor with a plurality of gaseous fuel nozzles and a plurality of air inlets, and a permanent magnet motor generator; see, e.g.,

FIGS. 1 and 2

of such patent and the description associated with such Figures.




The assignee of U.S. Pat. No. 5,819,524 manufactures and sells micro turbine generators, such as those described in its patent.




Similar micro turbine generators


314


are also manufactured and sold by Elliott Energy Systems company of 2901 S.E. Monroe Street, Stuart, Fla. 34997 as “The TA Series Turbo Alternator.”




Such micro turbines are also manufactured by the Northern Research and Engineering Corporation (NREC), of Boston, Mass., which is a wholly-owned subsidiary of Ingersoll-Rand Company; see, e.g., page 64 of the June, 1998 issue of “Diesel & Gas Turbine Worldwide.” These micro turbines are adapted to be used with either generators (to produce micro turbine generators) or, alternatively, without such generators in mechanical drive applications. It will be apparent to those skilled in the art that applicants' rotary positive displacement device may be used with either of these applications.




In general, and as is known to those skilled in the art, the micro turbine generator


314


is comprised of a radial, mixed flow or axial, turbine and compressor and a generator rotor and stator. The system also contains a combustor, bearings and bearings lubrication system. The micro turbine generator


314


operates on a Brayton cycle of the open type; see, e.g., page 48 of the June, 1998 issue of “Diesel & Gas Turbine Worldwide.”




Referring again to

FIG. 13

, and in the preferred embodiment depicted therein, it will be seen that natural gas is fed via line


310


to manual ball valve


318


and thence to Y-strainer


320


, which removes any heavy, solid particles entrained within the gas stream. The gas is then passed to check valve


322


, which prevents backflow of the natural gas. Relief valve


324


prevents overpressurization of the system.




The natural gas is then fed via line


326


to the compressor


316


, which is described elsewhere in this specification in detail. Referring to

FIG. 13

, it will be seen that compressor


316


is operatively connected via distance piece


328


, housing a coupling (not shown) which connects the shafts (not shown) of compressor


316


and electric motor


330


. The compressor


316


, distance piece


328


, and electric motor


330


are mounted on or near a receiving tank, which receives and separates a substantial portion of the oil used in compressor


316


.




Referring again to

FIG. 13

, when the compressor


316


has compressed a portion of natural gas, such natural gas also contains some oil. The gas/oil mixture is then fed via line


334


to check valve


336


(which prevents backflow), and thence to relief valve


338


(which prevents overpressurization), and then via line


340


to radiator/heat exchanger


342


.




Referring again to

FIG. 13

, it will be seen that oil is charged into the system via line


344


through plug


346


. Any conventional oil or lubricating fluid may be used; in one embodiment, automatic transmission fluid sold as “ATF” by automotive supply houses is used.




A portion of the oil which was introduced via line


344


resides in the bottom of tank


332


. This portion of the oil is pressurized by the natural gas in the tank, and the pressurized oil is then pushed by pressurized gas through line


348


, through check valve (to eliminate back flow), and then past needle valve


352


, into radiator


354


; a similar needle valve


352


may be used after the radiator


354


. The oil flowing into radiator


354


is then cooled to a temperature which generally is from about 10 to about 30 degrees Fahrenheit above the ambient air temperature. The cooled oil then exits radiator


354


via line


356


, passes through oil filter


358


, and then is returned to compressor


316


where it is injected; the injection is controlled by solenoid valve


360


.




In the preferred embodiment depicted in

FIG. 13

, a fan


362


is shown as the cooling means; this fan is preferably driven by motor


364


; in the preferred embodiment depicted in

FIG. 13

, air is drawn through radiators


342


and


354


in the direction of arrows


363


. As will be apparent to those skilled in the art, other cooling means (such as water cooling) also and/or alternatively may be used.




Referring again to

FIG. 13

, the cooled oil and gas mixture from radiator


342


is passed via line


366


through ball valve


368


and then introduced into tank


332


at point


370


.




In the operation of the system depicted in

FIG. 13

, a sight gauge


380


provides visual indication of how much oil is in receiving tank


332


. When an excess of such oil is present, it may be drained via manual valve


384


. In general, it is preferred to have from about 20 to about 30 volume percent of the tank be comprised of oil.




Referring again to

FIG. 13

, compressed gas may be delivered to turbogenerator


314


through port


386


, which is preferably located on receiving tank


332


but above the oil level (not shown) in such tank. Bypass line


388


and pressure relief valve


390


allows excess gas flow to be diverted back into inlet line


326


. That gas which is not in bypass line


388


flows via line


313


through check valve


392


(to prevent backflow), manual valve


394


and thence to turbogenerator


314


.




Thus, and again referring to

FIG. 13

, it will be seen that, in this preferred embodiment, there is a turbo alternator


314


, an oil lubricated rotary displacement compressor


316


, a receiving tank


332


, a means


310


for feeding gas to the rotary positive displacement compressor, a means


346


for feeding oil to the receiving tank, a means


342


for cooling a mixture of gas and oil, a means


332


for separating a mixture of gas and oil, and a means


356


for feeding oil to the rotary positive displacement compressor.




In the preferred embodiment depicted in

FIG. 13

, there are two separate means for controlling the flow capacity of compressor


316


. One such means, discussed elsewhere in this specification as a bypass loop (such as, e.g., a bypass valve or regulator), is the combination of port


386


, line


388


, relief valve


390


, and line


391


. Another such means is to control the inlet flow of the natural gas by means of control valve


396


. As will be apparent, both such means, singly or in combination, exert their control in response to the gas needs of turbogenerator


314


. As will be apparent, other such means may be used. Thus, e.g., one may utilize a variable speed drive operatively connected to the compressor which will vary the compressor speed in response to the demand for compressed gas exhibited by the microturbine(s) or other primer mover(s). Such a variable speed drive is commercially available and may be obtained, e.g., as Fincor Electrics 6500 Series Adjustable Speed Act Motor Controller.





FIG. 14

is a schematic representation of a hybrid booster system


420


which is comprised of a rotary positive displacement device assembly


422


operatively connected via line


424


to a reciprocating compressor


426


.




Rotary positive displacement device assembly


422


may be comprised of one or more of the rotary positive displacement devices depicted in either

FIGS. 1-8

(with solid rollers) and/or


9


-


11


(hollow rollers). Alternatively, or additionally, the displacement device


422


may be comprised of one or more of the rotary compressors claimed in U.S. Pat. No. 5,769,619, the entire disclosure of which is hereby incorporated by reference into this specification. A variable speed drive assembly may be operatively connected to one of these compressors. In one aspect of this embodiment, each compressor in the system is connected to a variable speed drive.




In one embodiment, a variable speed drive (not shown) is operatively connected to one compressor; and other compressors in the system are not operatively connected to such variable speed drive.




U.S. Pat. No. 5,769,619 claims a rotary device comprised of a housing comprising a curved inner surface in the shape of a trochoid and an interior wall, an eccentric mounted on a shaft disposed within said housing, a first rotor mounted on said eccentric shaft which is comprised of a first side and a second side, a first pin attached to said rotor and extending from said rotor to said interior wall of said housing, and a second pin attached to said rotor and extending from said rotor to said interior wall of said housing, and a third pin attached to said rotor and extending from said rotor to said interior wall of said housing. A continuously arcuate track is disposed within said interior wall of said housing, wherein said continuously arcuate track is in the shape of an envoluted trochoid. Each of said first pin, said second pin, and said third pin has a distal end which is disposed within said continuously arcuate track. Each of said first pin, said second pin, and said third pin has a distal end comprised of a shaft disposed within a rotatable sleeve. The rotor is comprised of a multiplicity of apices, wherein each such apex forms a compliant seal with said curved inner surface, and wherein each said apex is comprised of a separate curved surface which is formed from a strip of material pressed into a recess. The curved inner surface of the housing is generated from an ideal epictrochoidal curve and is outwardly recessed from said ideal epitrochoidal curve by a distance of from about 0.05 to about 5 times as great as the eccentricity of said eccentric. The diameter of the distal end of each of said first pin and said second pin is from about 2 to about 4 times as great as the eccentricity of the eccentric. Each of the first pin, the second pin, and the third pin extends from beyond the interior wall of the housing by from about 2 to about 2 times the diameter of each of said pins.




Referring again to

FIG. 14

, it is preferred that several rotary positive displacement devices


10


and


10


′ be used to compress the gas ultimately fed via line


424


to reciprocating positive compressor


426


. As is disclosed in U.S. Pat. No. 5,431,551, the devices


10


and


10


′ are staged to provide a multiplicity of fluid compression means in series.




Thus, as was disclosed in U.S. Pat. No. 5,431,551 (see lines 62 et seq. of column 9), “In one embodiment, not shown, a series of four rotors are used to compress natural gas. The first two stacked rotors are substantially identical and relatively large; they are 180 degrees out of phase with each other; and they are used to compress natural gas to an intermediate pressure level of from about 150 to about 200 p.s.i.g. The third stacked rotor, which comprises the second stage of the device, is substantially smaller than the first two and compresses the natural gas to a higher pressure of from about 800 to about 1,000 p.s.i.g. The last stacked compressor, which is yet smaller, is the third stage of the device and compresses the natural gas to a pressure of from about 3,600 to about 4,500 p.s.i.g.”




Many other staged compressor circuits will be apparent to those skilled in the art. What is common to all of them, however, is the presence of at least one rotary positive displacement device


10


whose output is directly or indirectly operatively connected to at least one cylinder of a reciprocating positive displacement compressor


426


.




One may use any of the reciprocating positive displacement compressor designs well known to the art. Thus, by way of illustration and not limitation, one may use one or more of the reciprocating positive compressor designs disclosed in U.S. Pat. Nos. 5,811,669, 5,457,964, 5,411,054, 5,311,902, 4,345,880, 4332,144, 3,965,253, 3,719,749, 3,656,905, 3,585,451, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring again to

FIG. 14

, it will be apparent that reciprocating positive displacement compressor


426


may be comprised of one or more stages. In the preferred embodiment depicted, compressor


426


is comprised of stages


428


and


430


.




Referring again to

FIG. 14

, an electric motor


432


connected by shafts


434


and


436


is operatively connected to compressors


428


/


430


and


10


/


10


′. It will be apparent that many other such drive assemblies may be used.




In one embodiment, not shown, the gas from one stage of either the


10


/


10


′ assembly and/or the


428


/


430


assembly is cooled prior to the time it is passed to the next stage. In this embodiment, it is preferred to cool the gas exiting each stage to a temperature of at least about 10 degrees Fahrenheit above ambient temperature prior to the time it is introduced to the next compressor stage.





FIG. 15

depicts an assembly


450


similar to the assembly


420


depicted in FIG.


14


. Referring to

FIG. 15

, it will be seen that gas is fed to compressor assembly


10


/


10


′ by line


452


. In this embodiment, some pressurized gas at an intermediate pressure is fed from compressor


10


via line


454


to turbine or micro-turbine or fuel cell


456


. Alternatively, or additionally, gas is fed to electrical generation assembly


456


by a separate compressor (not shown).




The electrical output from electrical generation assembly


456


is used, at least in part, to power electrical motor


432


. Additionally, electrical power is fed via lines


458


and/or


460


to an electrical vehicle recharging station


462


and/or to an electrical load


464


.




Referring again to

FIG. 15

, and in the preferred embodiment depicted therein, waste heat produced in turbine/microturbine/fuel cell


456


is fed via line


466


to a heat load


468


, where the heat can be advantageously utilized, such as, e.g., heating means, cooling means, industrial processes, etc. Additionally, the high pressure discharge from compressor


430


is fed via line


470


to a compressed natural gas refueling system


472


.




In one embodiment, not shown, guided rotor assembly


10


/


10


′ is replaced by conventional compressor means such as reciprocating compressor, or other positive displacement compressor. Alternatively, or additionally, the reciprocating compressor assembly may be replaced by one or more rotary positive displacement devices which, preferably, are adapted to produce a more highly pressurized gas output than either compressor


10


or compressor


10


′. Such an arrangement is illustrated in

FIG. 16

, wherein rotary positive displacement devices


11


/


11


′ are the higher pressure compressors. In one embodiment, not shown, separate electrical motors are used to power one or more different compressors.





FIG. 17

is a schematic representation of an assembly


500


in which electrical generation assembly


456


is used to power a motor


502


which is turn provides power to rotary positive displacement device


504


. Gas from well head


506


is passed via line


508


, and pressurized gas from rotary positive displacement device


504


is fed via line


510


to electrical generation assembly


456


, wherein it is converted to electrical energy. Some of this energy is fed via line


512


to electric motor


432


, which provides motive power to a single or multi-compressor guided rotary compressor


514


; this “well head booster” may be similar in design to the compressor assembly illustrated in

FIGS. 1-8

, or to the compressor assembly illustrated in

FIGS. 9-12

, and it may contain one more compressor stages. The output from rotary positive displacement assembly


514


may be sent via line


516


to gas processing and/or gas transmission lines. The input to rotary positive displacement assembly


514


may come from well head


518


, which may be (but need not be) the same well head as well head


506


, via line


520


.




Multistage Rotor Assembly





FIG. 18

is a sectional view of a multistage rotor assembly


600


which is comprised of a shaft


602


integrally connected to eccentric


604


and eccentric


606


. The rotating shaft


600


/eccentric


604


/eccentric


606


assembly is supported by main bearings


608


and


610


; eccentrics


604


and


606


are disposed within bearings


612


and


614


; and the eccentrics


604


/


606


and bearings


612


/


614


assemblies are disposed within guided rotors


616


and


618


. This arrangement is somewhat similar to that depicted in

FIG. 1

, wherein eccentric


52


is disposed within guided rotor


60


.




As will be apparent to those skilled in the art, one shaft


602


is being used to translate two rotors


616


and


618


. The gas to be compressed is introduced into port


620


and then introduced into the volume created by the rotor


616


and the housing


622


. The compressed gas from the volume created by the rotor


616


and the housing


622


is then introduced within an annulus


624


within intermediate plate


626


via port


628


and then sent into the volume created by rotor


618


and housing


630


through port


632


. After being further compressed in this second rotor system, it is then sent to discharge annulus


632


within discharge housing


634


by port


636


.




Referring to

FIG. 1

, it will be seen that guided rotor assembly


10


has a housing


12


with a thickness


640


which is slightly larger than the thickness of the rotor


16


disposed within such housing (see FIG.


1


). Similarly, the thickness


642


of rotor assembly


616


, and the thickness


644


of rotor assembly


618


are also slightly smaller than the thicknesses of the housings in which the guided rotors are disposed.




It is preferred that the thickness


644


be less than the thickness


642


. In one embodiment, thickness


642


is at least 1.1 times as great as the thickness


644


and, preferably, at least 1.5 times as great as the thickness


644


.




It will be apparent that, with the assembly


600


of

FIG. 18

, one can achieve higher pressures with lower operating costs.




A Hermetically Sealed Guided Rotor Apparatus





FIG. 19

illustrates an guided rotor assembly


670


comprised of a multiplicity of guided rotors


672


and


674


. Shaft


676


is rotated by electric motor


678


which, in the embodiment depicted, is comprised of motor shaft


680


, motor rotor


682


, and stator


684


supported by bearings


686


and


688


. The motor shaft


680


is directly coupled to compressor shaft


676


by means a coupling


690


.




The compressor shaft


676


rotates one or more of rotors


672


and


674


, which may be of the same size, a different size, of the same function, and/or of a different function.




The motor


678


is cooled by incoming gas (not shown), and such incoming gas is then passed to compressor


692


, wherein it is distributed equally to the rotor assemblies


672


and


674


, which are disposed within housings


694


and


696


, respectively.




In the embodiment depicted in

FIG. 19

, the rotor assemblies


674


and


676


have substantially the same geometry and capacity. In another embodiment, not shown, the rotor assemblies


674


and


674


have different geometries and/or capacities.




Referring again to

FIG. 19

, it will be seen that the entire compressor and drive assembly is disposed within hermetic enclosure


698


. The end flange


700


is form an interface


702


with enclosure


698


which is a hermetic seal.





FIG. 20

is a schematic of an assembly


750


for generating electric power and recovering thermal energy for other useful work. Referring to

FIG. 20

, it will be seen that a multiplicity of micro turbines


752


,


754


,


756


, and


758


are used to generate electricity which, in the embodiment depicted, is fed from the unit at outlet


760


.




In one embodiment, a micro turbine such as those sold by the Capstone Turbine Corporation of Woodland Hills, Calif. may be used. Thus, e.g., the Model 330 Capstone Micro Turbine may be used. Thus, e.g., one may use one or more of the micro turbines disclosed in U.S. Pat. Nos. 5,903,116, 5,899,673, 5,850,733, 5,819,524, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring again to

FIG. 20

, the heat discharged from one or more of micro turbines


752


,


754


,


756


, and/or


758


is passed to waste heat boilers


761


and/or


762


, wherein the waste heat is used to heat fluid, such as water, and to preferably generate either hot water or steam. The hot fluid from waste heat boilers


761


and/or


762


is then passed via lines


764


and


766


to industrial processes


768


and


770


. Any industrial or commercial processes which utilize heat energy may be used in the process. Thus, the waste heat may be used to heat or cool working space, inventory space, etc.; it may be used to heat chemical reagents; it may, in fact, be used in any process which requires heat. Conventional means, such as pipes, heat exchangers, and the like (see, e.g., heat exchanger


771


) may be used to extract heat from the heated fluid.




In one embodiment, not shown, the exhaust gases from micro turbines


752


,


754


,


756


, and/or


758


into the air inlet of a combustion boiler, or into any other device which can profitably utilize such hot gasses.




Referring again to

FIG. 20

, it will be seen that a multiplicity of guided rotor compressors


772


and


774


supply compressed natural gas to the micro turbines


752


,


754


,


756


, and/or


758


. Accumulator


776


accumulates compressed gas produced by compressors


772


and/or


774


; and, as needed, it also may supply compressed gas to micro turbines


752


,


754


,


756


, and


758


.




A Process for Controlling Compressors





FIG. 21

is a schematic diagram of a system


800


for generating electricity which is comprised of a multiplicity of microturbines


752


,


754


,


756


, and


758


which are described elsewhere in this specification. The system


800


also is comprised of a multiplicity of compressors


802


,


804


, and


806


.




Although four microturbines


752


et seq. are shown in the system depicted in

FIG. 21

, fewer or more microturbines can be used. It is preferred to use at least two such microturbines in the system


800


, but one can use many more in such system such as, e.g., 60 microturbines.




Although three compressors


802


et seq. are shown in the system depicted in

FIG. 21

, fewer or more such compressors may be used. It is preferred to use at least two such compressors in the system


800


, but one can use many more such compressors such as, e.g., 60 compressors.




One may use the guided rotor compressor, described and claimed in U.S. Pat. No. 5,431,551, as one or more of the compressors in system


800


. Alternatively, or additionally, one may use one or more of the “hollow roller compressors,” described elsewhere in this specification, as one or more of the compressors in system


800


. Alternatively, or additionally, one may use other types of compressors such as, e.g., scroll compressors, vane compressors, twin screw compressors, reciprocating compressors, continuous flow compressors, and the like.




Regardless of the compressor, it should be capable of compressing gas to a pressure of from about 40 to about 500 pounds per square inch and of delivering such compressed gas at a flow rate of from about 5 to about 200 standard cubic feet per minute (“scfm”). The term “scfm” is well known to those skilled in the art, and means for measuring it are also well known. See, e.g. U.S. Pat. Nos. 5,672,827, 4,977,921, 5,695,641, 5,664,426, 5,597,491, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring to

FIG. 21

, when system


800


has been shut down and is in the process of just starting up, compressed gas at a pressure of from about 40 to about 500 pounds per square inch is first delivered to microturbine


752


.




In the embodiment depicted in

FIG. 21

, it is preferred to use a pressure regulator


836


in line


313


to insure that gas delivered to microturbine(s)


752


and/or


754


and/or


756


and/or


758


is stable and remains within a specified range of gas pressure.




In the embodiment shown in Figure, reservoir


808


generally will contain a source of compressed gas at a pressure of from about 40 to about 500 pounds per square inch, and this compressed gas may be fed via lines


313


and


810


to microturbine


752


.




Reservoir


808


can be any container sufficient for storing and/or dispensing gas at a pressure of from about 40 to about 500 pounds per square inch. Thus, by way of illustration and not limitation, one may use any of the gas storage vessels disclosed in U.S. Pat. Nos. 5,908,134, 5,901,758, 5,826,632, 5,798,156, 5,997,611, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




In the embodiment depicted in

FIG. 21

, gas storage vessel


808


acts as the initial supply of compressed gas to microturbine


752


. In another embodiment, not shown, gas storage vessel


808


is not used in the system and compressed gas is fed to microturbine


752


from another initial gas source such as, e.g., gas delivery line


810


.




Referring again to

FIG. 21

, after the compressed gas has been delivered to microturbine


752


from either storage vessel


808


and/or line


810


, the microturbine starts operation. In the embodiment depicted in

FIG. 21

, each of microturbines


752


,


754


,


756


, and


758


is comprised of its own controller which, in response to the introduction of gas to such microturbine, starts it in operation. In another embodiment, a central controller operatively connected to each of microturbines


752


,


754


,


756


, and


758


, and to each of compressors


802


,


804


, and


806


, is utilized.




Referring again to

FIG. 21

, each of compressors


802


,


804


, and


806


is operatively connected to a controller


812


,


814


, and


816


, respectively. In another embodiment, not shown, one controller (not shown) is connected to each of the compressors; this controller might be a computer, a programmable logic controller, etc. In one aspect of this latter embodiment, one controller is operatively connected to each of the compressors, but such unitary controller includes a separate gas pressure sensor device for each such compressor. It is preferred, regardless whether one uses one or more controllers, that each such controller contain a separate gas sensing device for each compressor.




Regardless of which controller or controllers are connected to the compressors


802


,


04


, and


806


, it is preferred that such controllers(s) be comprised of pressure sensing means (not shown) for measuring the pressure of gas. Thus, for example, the pressure sensing means may be pressure switches which combine the function of pressure sensing and electrical switching. Thus, e.g., the pressure sensing means may be pressure transducers adapted to provide a signal to a programmable logic controller.




Regardless of the pressure sensing means used, such means is adapted to determine the pressure within either vessel


808


and/or line


810


. When such pressure is outside of a specified desired range of a pressure, but is within the broad pressure range of from about 40 to about 500 pounds per square inch, the pressure sensing means acts as a switch to turn one or more of compressors


802


,


804


, and/or


806


on or off, depending upon the pressure sensed.




Referring again to

FIG. 21

, the controllers


812


,


814


, and


816


are operatively connected to compressors


806


,


804


, and


802


, respectively, by lines


818


and


820


,


822


and


824


, and


826


and


828


, respectively. It should be noted that lines


820


,


824


, and


828


, in one embodiment, preferably comprise a manual switch


830


,


832


, and


834


, respectively to allow one to manually control each of the compressors.




As will be apparent to those skilled in the art, one or more of the manual switches


830


,


832


, and/or


834


may be used in conjunction with the controllers


812


,


814


, and


816


. When one or more of the controllers


812


,


814


, and/or


816


are connected in the system


800


, the manual switches may be used to disconnect the compressors and negate the effects of the controllers. If the controllers


812


,


814


, and/or


816


are omitted from system


800


, one may manually perform the operations of such controllers by using such switches in response to gas pressure readings may be manual means.




In one embodiment, the controllers


812


,


814


, and


816


are programmed to turn compressors


802


,


804


, and


806


on sequentially, in response to the presence of different gas pressure levels within either vessel


808


or line


810


. This feature will be illustrated later in the specification by reference to FIG.


23


.




Thus, in one typical embodiment, compressor


802


will be turned on when the gas pressure in vessel


808


and/or line


810


is less than, e.g., 60 pounds per square inch; compressors


802


,


804


, and


806


may be fed gas from gas lines


310


,


311


,


313


, and


315


. When this condition occurs, compressor


802


will be switched on and will cause compressed gas to flow to microturbine


752


at a flow rate of, e.g., 7 standard cubic feet per minute.




During the operation of compressor


802


, and as long as the gas flow from compressor


802


is sufficient to meet the needs of whichever of microturbines


752


,


754


,


756


, and/or


758


is running, the gas pressure within vessel


808


and line


810


preferably remains at a specified value such as, e.g., 60 pounds per square inch.




After controller


816


has activated compressor


802


, when one or more of the sensors in controller


814


senses that the gas pressure within vessel


808


and line


810


has dropped below a desired value, such as, e.g., 55 pounds per square inch, it will then turn on compressor


804


so that it is operating in addition to compressor


802


.




Similarly, when compressors


802


and


804


are running, and the sensor in, e.g., controller


812


senses that the gas pressure within vessel


808


and/or line


810


has dropped below a desired value such as, e.g., 50 pounds per square inch, it will turn on compressor


806


.




The same process may be used in the reverse order, when one or more of the controllers


812


,


814


, and


816


sense that the pressure within vessel


808


and/or line


810


exceeds a certain predetermined value. Thus, e.g., compressor


806


may be turned off when the pressure sensed is greater than about, e.g., 65 pounds per square inch, compressor


804


may be turned off when the pressure sensed is greater than about, e.g., 66 pounds per square inch, and compressor


802


may be turned off when the pressure sensed is greater than about 67 pounds per square inch.




As will be apparent to those skilled in the art, other conditions and sequences may be used. What is common to all of the processes, however, is the sequential turning on and/or turning off of a multiplicity of compressors.





FIG. 22

illustrates one preferred means of providing pressure relief in an electricity generating system


800


.




Referring to

FIG. 22

, when the pressure within pressure vessel


808


exceeds a specified value, pressure relief valve


850


allows such pressure to vent via line


852


to atmosphere. Thus, e.g., valve


850


can be set to open when, e.g., the pressure within vessel


808


exceeds, e.g., 150 pounds per square inch.




A bypass relief valve


854


is set to open whenever the pressure within vessel


808


exceeds a specified value. In one embodiment, the pressure required to actuate valve


850


is greater than the pressure required to actuate valve


854


; if the former pressure, e.g., may 150 pounds per square inch and the latter pressure may be, e.g., 70 pounds per square inch. As will be apparent to those skilled in the art, the actual actuation points for valves


850


and


854


will vary depending upon factors such as the rating of the vessel


808


, the power ratings of compressors


802


,


804


, and


806


, the pressures required in the system, etc.




Referring again to

FIG. 22

, when valve


854


is actuated, gas flows from vessel


808


through line


856


and then through check valve


858


back into line


310


at point


860


. Check valve


862


prevents gas recycled into the system at point


860


from flowing back to the original gas supply


864


.




Referring again to

FIG. 22

, and in the preferred embodiment depicted therein, it will be seen that each of compressors


802


,


804


, and


806


is comprised of a pressure relief valve


866


,


868


, and


870


which, when the pressure within the compressor discharge


872


,


874


, and


876


exceeds a certain specified value, gas is vented to the atmosphere


878


. Thus, e.g., pressure relief valves


866


,


868


, and


870


may be designed to actuate at a pressure of, e.g., 150 pounds per square inch.




When the gas pressure at compressor discharge


872


,


874


, and


876


is less than the pressure required to actuate valves


866


,


868


and


870


but is more than another specified value (such as, e.g., 80 pounds per square inch), bypass relief valves


880


,


882


, and


884


open and flow gas through lines


886


,


888


, and


890


through check valves


892


,


894


, and


896


and thence back into lines


311


,


313


, and


315


. In one embodiment, the relief valves


880


,


882


, and


884


are set to be actuated at levels somewhat lower than the settings in controllers


816


,


814


, and


812


for turning the compressors off (see FIG.


21


).




Referring again to

FIG. 22

, it will be seen that the gas exiting from compressors


802


,


804


, and


806


via lines


898


,


900


, and


902


pass through check valves


904


,


906


, and


908


which can be used to prevent backflow.





FIG. 23

is a graph of pressure versus the number of compressors operating, in the system depicted in FIG.


21


.




As is illustrated in

FIG. 23

, the pressure P


1


, which is within the range defined by points


910


and


912


, exists when each of compressors


802


,


804


, and


806


are operating. The pressure P


2


, which is within the range defined by points


914


and


916


, exists when only compressors


802


and


804


are operating. The pressure P


3


, which is defined by the points


918


and


920


, exists when only compressor


802


is operating. The pressure P


4


, which is defined by a pressure in excess of the pressure at point


920


, exists when the pressure vessel


808


has a pressure outside of the desired range and at least one compressor is operating and producing pressure outside of the desired range, which causes bypass relief valve


854


(see

FIG. 21

) to open and reduce the pressure at or below level


920


.




A Phased Rotary Displacement Device




The instant invention is comprised of an improvement on the structure disclosed in U.S. Pat. No. 5,769,619.





FIG. 24

is an exploded perspective view of one preferred rotary mechanism


1010


. Referring to

FIG. 24

, it will be seen that rotary mechanism


1010


is comprised of housing


1012


, shaft


1014


, rotor


1016


, external gear


1018


, internal gear


1020


, eccentric


1022


, bearing


1024


, and side plate


1026


.




Referring again to

FIG. 24

, it will be seen that housing


1012


is preferably an integral structure. However, housing


1012


may comprise two or more segments joined together by conventional means such as, e.g., bolts.




In one embodiment, housing


1012


consists essentially of steel. As is known to those skilled in the art, steel is an alloy of iron and from about 0.02 to about 1.5 weight percent of carbon; it is made from molten pig iron by oxidizing out the excess carbon and other impurities (see, e.g., pages 23-14 to 23-56 of Robert H. Perry et al's “Chemical Engineer's Handbook,” Fifth Edition (McGraw-Hill Book Company, New York, N.Y., 1973).




In another embodiment, housing


1012


consists essentially of aluminum. In yet another embodiment, housing


1012


consists essentially of plastic. These and other suitable materials are described in George S. Brady et al.'s “Materials Handbook,” Thirteenth Edition (McGraw-Hill, Inc., New York, N.Y., 1991).




In another embodiment, housing


1012


consists essentially of ceramic material such as, e.g., silicon carbide, silicon nitride, etc.




In one embodiment, housing


1012


is coated with a wear-resistant coating such as, e.g., a coating of alumina formed electrolytically, electroless nickel, tungsten carbide, etc.




One advantage of applicant's rotary mechanism


1010


is that the housing need not be constructed of expensive alloys which are resistant to wear; and the inner surface of the housing need not be treated with one or more special coatings to minimize such wear. Thus, applicants' device is substantially less expensive to produce than prior art devices.




Housing


1012


may be produced from steel stock (such as, e.g., C1040 steel stock) by conventional milling techniques. Thus, by way of illustration, one may use a computer numerical controlled milling machine which is adapted to cut a housing


1012


with the desired curved surface.




Similarly, the rotor


1016


may be made of any material(s) from which the housing


1012


is made.




Referring again to

FIG. 24

, and in the preferred embodiment depicted therein it will be seen that housing


1012


is comprised of an external gear


1018


mounted on an inner wall


1026


of such housing


1012


. The external gear


1018


is so disposed that, when drive shaft


1014


is disposed therein, the gear


1018


is concentric to the drive shaft


1014


.




The external gear


1018


preferably has a substantially circular cross-sectional shape.




In order for the external gear


1018


and the internal gear


1020


to phase properly the rotor


1016


in the housing


1012


, they have to meet two different conditions. In the first place, the difference between the two pitch diameters of the internal and external gears must be exactly twice the eccentricity of the shaft


1022


. In the second place, the ratio between the pitch diameters of the internal and external gears must be the same as the ratio between the numbers of sides in rotor


1016


divided by the number of lobes in housing


1012


. These criteria will be discussed in more detail later in this specification.




The eccentricity of eccentric


1022


generally will be from about 0.05 to about 10 inches. It is preferred that the eccentricity be from about 0.15 to about 1.5 inches.




Referring again to

FIG. 24

, and in the preferred embodiment depicted therein, it will be seen that bearing


1024


can either be a sleeve bearing and/or a rolling element bearing.




Referring to

FIG. 25

, it will be seen that rotor


1016


is comprised of a bore


1028


with a center line


1034


and an internal diameter


1042


. The internal diameter


1042


of bore


1028


is smaller than the pitch diameter


1030


of internal gear


1020


.




As is known to those skilled in the art, the term pitch diameter refers to the diameter of an imaginary circle, which commonly is referred to as the “pitch circle,” concentric with the gear axis


1034


, which rolls without slippage with a pitch circle of a mating gear. Reference may be had, e.g., to U.S. Pat. Nos. 5,816,788, 5,813,488, 5,704,865, 5,685,269, 5,474,503, 5,454,175, 5,387,000, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring again to

FIG. 25

, it will be seen internal diameter


1042


is also smaller than diameter


1032


of the addendum circle of internal gear


1020


. As is known to those skilled in the art, the addendum circle is a circle on a gear passing through the tops of the gear teeth. See, e.g., U.S. Pat. Nos. 5,438,732, 5,154,475, 5,090,771, 4,864,893, 4,813,853, 4,780,070, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring again to

FIG. 25

, it will be seen that two internal gears


1020


and


1021


are depicted, one of which is disposed at end


1046


of the rotor


1016


, and the other which is disposed at end


1048


of rotor


1016


. In the preferred embodiment depicted, each of gears


1020


and


1021


is disposed within a counterbore (


1050


and


1052


, respectively). In another embodiment, not shown, only one gear


1020


or


1021


is disposed on one side of rotor


1016


.




The gears


1020


,


1021


may be attached to rotor


1016


by conventional means such as, e.g., by mechanical means (using fasteners such as bolts, internal retaining rings, etc.), by interference fit, by electron beam welding, etc.




In the embodiment depicted in

FIG. 24

, the rotor


1016


contains four sides and has a substantially square shape. As will be apparent to those skilled in the art, one may use rotors with 3 sides (not shown), 5 sides, 6 sides, etc. In general, it is preferred the rotor contain at least 3 sides and no more 6 sides.




Referring again to

FIG. 25

, it will be seen that an external gear


1018


is disposed within side plate


1026


and, more precisely, within counterbore


1054


of side plate


1026


. In the embodiment depicted, only one such external gear


1018


is shown disposed on one side plate. In another embodiment, not shown, two such external gears are used and are disposed on both sides of rotor


1016


. It will be apparent that, although only one side plate


1026


is shown in

FIGS. 24 and 25

for the sake of simplicity of representation, at least two such side plates generally are required for each housing, one for each side of the housing.




Referring again to

FIG. 25

, it will be seen that side plate


1026


is comprised of a bore


1050


with a centerline


1040


and an internal diameter


1044


. The internal diameter


1044


of bore


1050


is smaller than the pitch diameter


1036


of external gear


1018


.




It will be seen that internal diameter


1044


is also smaller than the diameter


1038


of the external gear


1018


, which is the inner bore of external gear


1018


.




The gear(s)


1018


may be attached to side plate


1026


by conventional means such as, e.g., by mechanical means (using fasteners such as bolts, internal retaining rings, etc.), by interference fit, by electron beam welding, etc.




As mentioned elsewhere in this specification, in order for the external gear


1018


and the internal gear


1020


to phase properly the rotor


1016


in the housing


1012


, two different conditions must be met. In the first place, the difference between the two pitch diameters of the internal and external gears (viz., pitch diameters


1030


, and


1036


) must be exactly twice the eccentricity of the shaft


1022


. In the second place, the ratio between the pitch diameters


1030


and


1036


of the internal and external gears must be the same as the ratio between the numbers of in rotor


1016


divided by the number of lobes in housing


1012


.





FIG. 26

is a schematic representation of trochoidal surface


1082


and envoluted trochoidal surface


1060


referred to in this specification. Referring to

FIG. 26

, and in the preferred embodiment depicted therein, it will be seen that surface


1060


defines a multiplicity of lobes


1062


,


1064


, and


1066


which, in combination, define an inner surface


1060


which has a continuously changing curvature.




Referring again to

FIG. 26

, it will be seen that, with regard to lobe


1062


, the distance from the centerpoint


1068


to any one point on lobe


1062


will preferably differ from the distance from the centerpoint to an adjacent point on lobe


1062


; both the curvature and the distance from the centerpoint


1068


is preferably continuously varying in this lobe (and the other lobes). Thus, for example, the distance


1070


between point


1068


and


1072


is preferably substantially less than the distance


1074


between points


1068


and


1076


; as one progresses from point


1012


to point


107


around surface


1060


, such distance preferably continuously increases as the curvature of lobe


1062


continuously changes. Thereafter, as one progresses from point


1076


to point


1078


, the distance


1080


between point


1068


and point


1078


preferably continuously decreases.




Referring again to

FIG. 26

, it will be apparent to those skilled in the art that, in this preferred embodiment, the same situation also applies with lobes


1066


and


1064


. Each of such lobes is preferably defined by a continuously changing curved surface; and the distance from the centerpoint


1068


is preferably continuously changing between adjacent points.




In the preferred embodiment illustrated in

FIG. 26

, it is preferred to have at least two of such lobes


1062


,


1064


, and


1066


. It is more preferred to have at least three of such lobes. In another embodiment, at least four of such lobes are present.




It is preferred that each lobe present in the inner surface


1060


have substantially the same curvature and shape as each of the other lobes present in inner surface


1060


. Thus, referring to

FIG. 26

, lobes


1062


,


106


, and


1066


are displaced equidistantly around centerpoint


1068


and have substantially the same curvature as each other.




The curved surface


1060


may be generated by conventional machining procedures. Thus, as is disclosed in U.S. Pat. No. 4,395,206, the designations “epitrochoid” and “hypotrochoid” surfaces refer to the manner in which a trochoid machine's profile curves are generated; see, e.g., U.S. Pat. No. 3,117,561, the entire disclosure of which is hereby incorporated by reference into this specification.




An epitrochoidal curve is formed by first selecting a base circle and a generating circle having a diameter greater than that of the base circle. The base circle is placed within the generating circle so that the generating circle is able to roll along the circumference of the base circle. The epitrochoidal curve is defined by the locus of points traced by the tip of the radially extending generating or drawing arm, fixed to the generating circle having its inner end pinned to the generating circle center, as the generating circle is rolled about the circumference of the base circle (which is fixed).




In one embodiment, the epitrochoidal curve is generated in accordance with the procedure illustrated in

FIG. 29

of U.S. Pat. No. 5,431,551, the entire disclosure of which is hereby incorporated by reference into this specification.




As is disclosed on lines 36 to 55 of column 5 of U.S. Pat. No. 4,395,206, it is common practice to recess or carve out the corresponding profile of the epitrochoid member a distance “x” equal to the outward offset of the apex seal radius (see

FIG. 4

of such patent). As is stated on lines


48


et seq. in such patent, in “ . . . the case of an inner envelope type device


20


′, as shown in

FIG. 4

, such carving out requires that the actual peripheral wall surface profile


33


which defines the cavity


34


of the housing


35


be everywhere radially outwardly recessed from the ideal epitrochoid profile


36


. In the case of an outer envelope device


21


′, as illustrated in

FIG. 5

, such carving out requires that the actual peripheral face profile of the epitrochoid working member, rotor


38


, be everywhere inwardly radially recessed from the ideal epitrochoid profile


39


.”




Referring again to

FIG. 26

, it will be seen that applicants' inner housing surface profile


1060


is generated from ideal epitrochoid curve


1082


and is outwardly recessed from ideal curve


1082


by a uniform distance


1084


. In one preferred embodiment, uniform distance


1084


is a function of the eccentricity of the eccentric


1022


used in device


1010


(see FIG.


24


).




Referring again to

FIG. 24

, it will be seen that rotary mechanism


1010


is comprised of a shaft


1014


on which the eccentric


1022


is mounted. Shaft


1014


preferably has a circular cross-section and is cylindrical in shape. Shaft


1014


is connected to eccentric


1022


. In one embodiment, illustrated in

FIG. 24

, shaft


1014


and eccentric


1022


are integrally formed and connected.




In one preferred embodiment, both shaft


1014


and eccentric


1022


consist essentially of steel such as, e.g., carbon steel which contains from about 0.4 to about 0.6 weight percent of carbon.





FIG. 4

of U.S. Pat. No. 5,431,551 is a front view of the shaft/eccentric assembly of this patent, and discussion is presented in such patent of the eccentricity of such assembly. As is known to those skilled in the art, eccentricity is the distance of the geometric center of a revolving body (eccentric


22


) from the axis of rotation.




Referring again to

FIG. 26

, and in the preferred embodiment illustrated therein, it is preferred that the distance


1084


be from about 0.5 to about 5.0 times as great as the eccentricity of eccentric


1022


(see FIG.


24


). In a more preferred embodiment, the distance


1084


is from about 1.0 to about 2.0 times as great as the eccentricity. In one embodiment, distance


1084


is about 0 times as great as the eccentricity.





FIG. 29

is a perspective view of a rotor assembly


1010


in which the apices


1086


,


1088


,


1090


, and


1092


are not directly contiguous with the inner surface


1056


of housing


1012


. In this embodiment, inner surface


1056


defines a theoretical trochoidal shape


1082


(see FIG.


28


).




The apparatus


1010


may comprise one or more of apex seals disclosed in

FIG. 6

of U.S. Pat. No. 5,769,619, the entire disclosure of which is hereby incorporated by reference into this specification. Thus,

FIGS. 4

,


5


,


6


,


7


, and


8


depict rotor(s)


16


with different types of sealing surfaces on each of its apices. In these Figures, for the sake of simplicity of representation, the external gear(s)


18


has been omitted.




Referring to

FIG. 28

, it will be seen that apex


1118


is preferably a solid curved surface which is made from the same material as is rotor


116


. In this embodiment, the apex


1118


is non-compliant, it provides close-clearance sealing at a distance of from about 0.0001 to about 0.002 inches from the inner surface of the housing (not shown), and it will describe an envoluted trochoidal geometry during its operation.




Referring to

FIG. 26

, apex


1120


is connected to an apex seal


1121


. In the embodiment depicted, apex seal


1121


is a linear strip seal which is disposed within rotor


116


. Linear strip seal


1121


can be metallic or non-metallic.




In one embodiment, where apex seal


1121


is a fixed strip of material, it provides close-clearance sealing at a distance of from about 0.001 to about 0.002 inches away from the inner surface of the housing and describes an ideal trochoidal geometry during its operation. In another embodiment, where the seal


1121


is made compliant by conventional means, it provides substantially zero clearance sealing and also describes an ideal trochoidal geometry during its operation.




Referring to

FIG. 30

, apex


1122


is comprised of a separate curved surface


1123


affixed to apex


1122


and made complaint by virtue of the presence of spring


1125


. In this embodiment, the apex


1122


provides substantially 0 clearance sealing and describes an envoluted trochoidal geometry during its operation. The surface


1123


may consist of an ultra-high molecular weight plastic.




Referring to

FIG. 31

, apex


1124


is comprised of a separate curved surface


1127


which is formed from a strip of material pressed into a recess (not shown) in rotor


116


. If this curved surface


1127


is made from compliant material, apex


1124


will also be compliant during operation, thereby providing substantially zero clearance, and will describe an envoluted trochoidal geometry during its operation. A port (not shown) communicating with the pressurized portion of a pressurized volume (not shown) may be employed to pressurize the back the curved surface


1127


, such that improved clearance control is achieved at higher pressures. In a similar manner, an equalizing pressure can also be applied to linear strip seal


1121


(see

FIG. 29

) and/or surface


1123


(see FIG.


30


).





FIG. 27

illustrates an embodiment in which each of the different apex sealing means described above exist with reference to one particular rotor


1016


. It will be apparent that other combinations of sealing means besides the ones depicted also may be used.




A Landfill Power Generation System





FIG. 32

is a schematic representation of a landfill power generation system


1200


which is comprised of compressor


1202


, compressor


1204


, landfill gas inlet


1206


, cooler


1208


, accumulator/separator


1210


, coalescent filter


1212


, pressure regulator


1214


, microturbine


1216


, microturbine


1218


, microturbine


1220


, microtrubine


1222


, waste heat boiler


1224


, and waste heat boiler


1226


.




In the operation of the process depicted in

FIG. 32

, landfill gas is introduced from line


1206


. The landfill gas may be derived from any landfill source by well known means. Thus, e.g., one may use any of the landfill gases described in U.S. Pat. Nos. 6,092,364, 6,090,312, 6,082,133, 6,080,226, 6,071,326, 6,061,637, 6,051,518, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Referring again to

FIG. 32

, the landfill gas introduced via line


1206


may optionally be fed to a dehumidifier


1228


in which the moisture level of the gas reduced to a dew point temperature of at least 20 degrees Fahrenheit less than the temperature of the untreated gas. One may use any conventional gas dehumidification device incorporating either a vapor compression cycle and/or an absorption cycle. Alternatively, one may use a chilled medium (such as water) produced in another process. Additionally, one may use a conventional radiator.




The gas introduced via line


1206


, which may optionally be dehumidified, is fed via line


1207


to one or more gas booster systems


1202


,


1204


, etc. The gas booster systems preferably a comprise a compressor and auxiliary systems such as lubrication systems, drive systems, cooling systems, etc. See the discussion of such systems which appears elsewhere in this specification.




For redundancy reasons, it is preferred to use at least two of such gas booster systems


1202


et seq.




The compressed gas from booster systems


1202


et seq. is then fed via line


1203


to optional cooler which, preferably, reduces the temperature of the gas stream by at least about 10 degrees Fahrenheit. The gas stream often contains a mixture of gas and oil; the oil is often introduced by the booster systems


1202


et seq.




The gas from cooler


1208


is then passed via line


1209


to an accumulator/separator


1210


which is described elsewhere in this specification. The accumulator/separator


1210


removes oil from the gas stream. Although only one accumulator/separator is shown in

FIG. 32

, more than one such accumulator/separator may be used. In one embodiment, two or more such accumulator/separators are used.




The gas from accumulator/separator(s)


1210


is then fed via line


1211


to one or more coalescent filters


1212


, which mechanically remove liquid from the gas stream. The coalescent filters are well known and are described, e.g., in U.S. Pat. Nos. 4,562,791, 4,822,387, 4,957,516, 5,001,908, 5,131,929, 5,306,331, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.




The filtered gas is then fed via line


1213


to a pressure regulator


1214


, which reduces the pressure of the filtered gas to the particular pressure required by the microturbine. Thus, e.g., Capstone model


330


microturbines requires fuel pressure at from 50 to 55 p.s.i.g.




The depressurized gas is then fed via line


1215


to one or more of microturbines


1215


,


1218


,


1220


, and


1222


. Although four microturbines are illustrated in

FIG. 32

, fewer (as few as one) or more such microturbines may be used.




The exhaust heat produced by the microturbines may optionally be fed to waste heat recovery systems


1224


and


1226


. One may use any conventional waste heat recovery system in this process such as, e.g., the waste heat recovery systems disclosed in U.S. Pat. Nos. 4,911,110, 4,911,359, 4,934,286, 4,936,869, 4,981,676, 4,982,511, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. Alternatively, or additionally, the heat from waste heat recovery systems


1224


/


1226


may be fed via line


1227


to provide the heat energy for absorption cycle utilized cooler


1208


and/or dehumidifier


1228


. In one embodiment, the dehumdifier


1228


utilizes one or more dessicants.





FIG. 33

is a schematic representation of another electricity generation system


1240


which preferably runs on digester gas. System


1240


is similar in some respects to system


1227


but differs therefrom in containing a digester system


1242


which produces gas from organic waste or biomass. Thus, one may use any of the digesters known to those skilled in the art such as, e.g., those describe in U.S. Pat. No. 4,274,838 (anaerobic digester for organic waste), U.S. Pat. No. 4,289,625 (hybrid bio-thermal gasification), U.S. Pat. No. 4,316,961 (methane production by anaerobic digestion of plant material and organic waste), U.S. Pat. No. 4,378,437 (digester apparatus), U.S. Pat. No. 4,384,552 (gas producing and handling device), and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.




In the preferred embodiment depicted in

FIG. 33

, waste heat from waste heat recovery systems


1224


and


1226


are preferably fed via line


1227


to the digester


1242


, wherein the heat is utilized to aid in the digestion process.





FIG. 34

is a sectional view of a preferred accumulator/separator


1210


which is comprised of a gas inlet port


1260


, an elbow


1262


, a baffle


1264


, a perforated screen


1266


, and a vent stack


1268


.




Gas is fed into inlet port


1260


and then is fed tangentially by an elbow


1262


. The gas is then forced to flow around baffle


1264


. In the embodiment depicted, baffle


1264


is a truncated cone. As will be apparent, however, other such baffles may be used, provided that such baffle has diameter which is smaller than the internal diameter of vessel


1265


or otherwise provides communication within vessel


1265


.




In one embodiment, instead of using elbow


1262


and tangential injection, linear injection of the gas is achieved with a straight pipe section (not shown).




The gas fed through elbow


1262


is preferably forced downwardly in the direction of arrow


1263


while simultaneously being accelerated in that direction.




The accelerated gas impinges against screen


1266


which disrupts the gas flow and causes liquid to separate from the gas and drop down into the direction of arrow


1267


into liquid pool


1269


, while the gas separated from the liquid then flows upwardly in the direction of arrow


1270


through the baffle


1264


and into a vent stack


1268


. In the embodiment depicted, vent stack


1268


contains surface impingement/filtering media such as, e.g., steel mesh, non-metallic filter media, steel wool, which is disposed within the vent stack


1268


. The filtered gas preferably flow through outlet port


1272


. As will be apparent, this accumulator/separator removes both liquid material and solid material from the gas stream. Other accumulator/separator devices also may be used, including those disclosed in U.S. Pat. Nos. 3,709,292, 3,739,627, 3,763,016, 3,766,745, 3,771,291, 3,773,558, 3,782,463, and the like. The entire disclosure of these United States patents is hereby incorporated by reference into this specification.





FIG. 36

is a front view of baffle


1266


.

FIG. 37

is a front view of vent stack


1268


from which the filter media


1271


has been omitted for the sake of simplicity of representation.

FIG. 38

is a top view of screen


1270


from which the perforations


1273


have been omitted in part for ease of representation.





FIG. 39

is a schematic of an electricity generation system comprised inlet


1207


, gas boost system


1202


, dehumidification system


1208


, accumulator/separator


1210


, coalescent filter


1212


, pressure regulator


1214


, and microturbine(s)


1216


. The accumulator/separator


1210


preferably contains a drain vent


1274


from which waste liquid may be removed.




Applicants have discovered that the use of both the accumulator/separator


1210


and the coalescent filter


1212


unexpectedly improves the purification of the gas and tends to minimize the impurities potentially introduced into the microturbine


1216


. Applicants have found that, by using two or more different purification mechanisms, an unexpectedly high degree of gas purification is obtained. If one were to use only two accumulator/separators


1274


, or only two coalescent filters


1212


, the desired degree purification would not be achieved.




In the preferred embodiment depicted in

FIG. 39

, two coalescent filters


1212


are connected in parallel; they are connected to two pressure regulators


1214


, also connected in parallel. Applicants have discovered that the use of two coalescent filters in parallel reduces the velocity of the gas and any remaining liquid through the coalescent filter, thereby increasing the filters' effectiveness. Two coalescent filters of a given size connected in parallel are more effective than one coalescent filter of double the size.




The purified gas stream is then introduced into microturbine


1216


.




It is preferred, when practicing the process depicted in

FIG. 39

, to feed a gas at a pressure of from about 0.1 to about 1,000 p.s.i.g. into line


1207


. It is preferred that the gas pressure be from about 0.25 to about 50 p.s.i.g.




The gas is then compressed in booster system


1202


to a pressure level at least 15 pounds per square inch greater than the pressure called for by the microturbine


1216


. In general, the gas is compressed in booster system


1202


to a pressure of at least about 65 pounds per square inch.




The pressurized gas is then optionally fed to a dehumidifier


1208


, where at least about ten percent is removed. Thereafter, the dehumidified gas is then fed to an accumulator/separator, in which both liquid material and solid material will be removed from the gas stream. In one embodiment, the majority of the liquid material removed is oil.




The material thus treated is then passed to the coalescent filter(s)


1212


, which removes liquid material from the accumulator separator.




The process depicted in

FIG. 39

is effective with substantially any compressor system. Thus, e.g., it works well with the guided rotor compressor described elsewhere in this specification. Thus, e.g., it works well with scroll compressors, twin-screw compressors, vane compressors, and reciprocating compressors. It is preferred that the compressor system used be an oil lubricated and/or oil flooded compressor. Thus, e.g., one may use a scroll compressor manufactured by the Copeland Company of Sidney, Ohio (see, e.g., U.S. Pat. No. 5,224,357, the entire disclosure of which is hereby incorporated by reference into this specification.)





FIG. 40

is a schematic representation of a packaging system


1300


in which gas is introduced via line


1302


into a system mounted on a skid


1304


. The configuration of system


1300


is similar to that of system


1200


(see

FIG. 32

) but differs therefrom in being an “open system” mounted on a skid. The system


1200


may be, but need not be, such an “open system.”




As is known to the those skilled in the art, microturbines


1216


et seq. are comprised of cabinets which protect the innards of such microturbines.




In the embodiment depicted in

FIG. 41

, by comparison, the system


1320


is comprised of a enclosure


1322


in which the components of the system are disposed. The enclosure


1322


may be metallic or nonmetallic. In one embodiment, such enclosure is constructed of concrete, as is shown in FIG.


42


.




Referring again to

FIG. 41

, because an enclosure


1322


is used, the individual components mounted within such enclosure


1322


need not be retained within their cabinets. Thus, in the embodiment depicted in

FIG. 41

, turbogenerators


1324


,


1326


,


1328


, and


1330


(which have been removed from the microturbine cabinets) are utillized in modular form as appropriate. One also may mount components such as the control systems


1332


,


1334


,


1336


, and


1338


(which also have been removed from microturbine cabinets), and/or battery packs (not shown) within the enclosure. As will be apparent, when such an enclosure


1322


is utilized, one has more flexilibility in packaging the components of the microturbine(s) at any desired location(s).





FIG. 42

is a perspective view of one preferred enclosure


1323


, which preferably is made from concrete. One may use precast concrete slabs, precast concrete buildings, or concrete construction on site. The benefit of using such a concrete structure, in addition to the flexibility afforded by modular systems, is the noise attenuation afforded by the use of the concrete. Furthermore, concrete structures are relatively inexpensive and relatively good looking, especially since a variety of architectural styles may be used to construct enclosure


1323


.




In the embodiment indicated, the enclosure


1323


is comprised of baffled inlet vents


1324


.





FIGS. 43A and 43B

are perspective views of two microturbines


1402


and


1404


which are manufactured by the Capstone Turbine Corporation of Chadsworth, Calif. as models


330


draw out package, and


330


industrial package, respectively. In the embodiments depicted, each of these microturbines generates a noise level of about 65 dba at ten meters. This noise often has an unpleasant, high frequency component which can attenuated by the addition of baffles


1406


and


1408


.




The baffles may be made out, or may comprise, sound absorbing material. Thus, e.g., the baffle can be made out of a rigid thermoplastic material to which is affixed a layer of sound absorbent material. Alternatively, the baffle can be made out of a metallic material to which a sound absorbent material has been affixed.




In any case, means for flowing air to the microturbine must be provided. In the embodiment depicted in

FIG. 43A

, air flows into the system through the bottom opening


1410


and the top opening


1412


. Similarly, in the embodiment depicted in

FIG. 43B

, air flows into the system through the side openings


1414


and


1416


.





FIG. 43C

is a partial sectional view of one preferred interior surface of baffle


1402


. Referring to

FIG. 43C

, it will be seen that sound waves


1420


emanating from the microturbine


1402


will preferably be reflected by and absorbed by the irregular surfaces


1422


disposed on the interior surface


1402


. Air is allowed to enter via opening


1412


, and some sound escapes through such opening; but, preferably, most of the sound is absorbed.





FIG. 21

A illustrates an electricity generation system similar to that depicted in

FIG. 21

with the exception the system


801


of

FIG. 21A

is comprised of a supplemental means of providing fuel to the system. In case the supply of natural gas is somehow interrupted, one may use propane gas from propane tank


803


which flows though line


805


to valve


807


. Valve


807


may either be a solenoid valve, or a manual valve.




When valve


807


is open in an emergency, the gas passing through such valve is generally at a pressure higher than that required by the microturbines


752


,


754


,


756


, and


758


. Thus, pressure regulator


809


reduces the gas pressure to the desired amount. Furthermore, in the embodiment depicted in

FIG. 21A

, a back pressure regulator


313


is disposed between the accumulator/separator


808


and the supply manifold


310


which supplies compressors


802


,


804


, and


806


. As will be apparent to those skilled in the art, this back pressure regulator is preferably set at a level slightly lower than highest turn off pressure for pressure transducers


812


,


814


, and


816


so that, in all cases, at least one compressor


802


,


804


, or


806


will run continuously even when loading on the microturbines and the gas requirement is low.




In one embodiment, not shown, check valves are utilized which prevent the propane gas from leaking into the natural gas supply lines, and vice versa. However, the propane gas, when used, is caused to flow into the manifold


313


from line


811


.





FIG. 44

is a schematic representation of a generation system


1500


comprising an electric motor


502


operatively connected to a variable speed drive


1502


; this variable speed assembly drives compressor


1504


whose output is fed via line


1506


to prime mover


1508


.




One may use any of the variable speed drives known to those skilled in the art. Thus, e.g., one may use one or more of the variable speed drives disclosed in U.S. Pat. No. 6,102,671 (scroll compressor operable at variable speeds), U.S. Pat. Nos. 6,041,615, 5,964,807, 5,894,736, 5,746,062, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




Thus, by way of further illustration, one may use an “Adjustable Speed AC Motor Controller” sold as “Fincor 6500” by the B&B Motor and Control Corporation of Rochester, N.Y.




Referring again to

FIG. 44

, the variable speed drive


1502


is operatively connected to motor


502


and controls its speed in response to information fed to drive


1502


from motor


502


(fed via line


1510


), and also in response to information fed to drive


1502


from prime mover


1508


(and fed via line


1512


). As the need for compressed gas from compressor


1504


varies, the speed of motor


502


will vary.




Assembly


1508


is any prime mover assembly which converts natural gas to electrical energy. Such prime mover assembly


1508


may be a microturbine (as discussed elsewhere in this specification), a fuel cell, a reciprocating engine, etc. The prime mover assembly includes a sensing means adapted to determine the gas pressure within the prime mover assembly and to activate the electric motor


502


to either deliver more or less gas, or to shut off, or to start. Thus, by way of illustration an not limitation, and referring to

FIG. 21

, pressure transducers (not shown) may be substituted for the controllers


812


,


814


, and


816


and operatively connected to the variable speed drive


1502


.




Referring again to

FIG. 44

, and in the preferred embodiment depicted therein, liquid is fed via line


1514


into liquid injection metering pump


1516


. One may use any of the liquid metering pumps known to those skilled in the art such as, e.g., one or more of the metering pumps disclosed in U.S. Pat. Nos. 6,123,324, 6,012,903 (positive displacement liquid metering pump), U.S. Pat. Nos. 4,349,130, 4,236,881, 4,021,153, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.




In the embodiment depicted in

FIG. 44

, the metering pump


1516


is operatively connected to motor


502


and compressor


1504


so that, as the speed of motor


502


is varied, the amount of liquid pumped by pump


1516


is also varied. The fluid pumped by pump


1516


lubricates and seals the compressor


1504


.




The liquid fed into line


1514


may be oil, it may be water, or it may be the liquid phase of the gas being compressed., or it may be a mixture of the above. The liquid may be fed to the compressor via external line


1518


and/or via internal passageways (not shown).




In one embodiment, the liquid being pumped is oil. In another embodiment, the liquid being pumped is water. In either case, it is preferred that the pump


1516


be capable of compressing the liquid prior to feeding it into compressor


1504


. In general, the pressure of the liquid being injected into the compressor


1504


will be from about 1 pounds per square inch gage to about 500 pounds per square inch gage and, preferably, from about 2 pounds per square inch gage to about 180 pounds per square inch gage.




When the fluid entering pump


1516


is at the desired pressure, there will be no need to further pressurize it with pump


1516


. When the pressure of the fluid entering the pump


1516


is too high, the metering device within the pump will reduce the flow of the fluid to the desired amount. When the pressure of the fluid entering the pump


1516


is too low, its pressure will be increased by the metering pump in order to maintain the desired flow rate.





FIGS. 45A through 45D

illustrate various configurations involving electric motor


502


, compressor


1504


, and metering pump


1516


. In these Figures, for the sake of simplicity of representation, the variable speed drive


1502


and prime mover


1508


have been omitted.




In each of the embodiments depicted in

FIGS. 45A through 45D

, a coupling


1520


may be used to couple motor


502


to the compressor


1504


. These couplings are well known to those skilled in the art. It is preferred that coupling


1520


be torsionally rigid.




In the embodiment depicted in

FIG. 45A

, the compressor


1504


is directly connected to the motor


502


by coupling


1520


. The motor


502


also is operatively connected to the pump


1516


.




In the embodiment depicted in

FIG. 45B

, a belt, chain, or gear set


1522


is connected to shaft


1524


, which in turn cases rotation of shaft


1526


and operation of pump


1516


.




In the embodiment depicted in

FIG. 45C

, a double-shafted motor


503


is utilized. End


505


of motor


503


is operatively connected to pump


1516


, which delivers fluid via line


1518


to compressor


504


.




In the embodiment depicted in

FIG. 45D

, a separate motor


507


is coupled via coupling


1520


to pump


1516


, which is hydraulically connected to compressor


1504


via line


1518


. In the embodiment depicted in

FIG. 45D

, it is preferred that motor


507


be driven by its own variable speed drive (not shown). It is preferred, in this embodiment, that the speed of motor


507


be synchronized with the speed of motor


502


.




A novel compressor


1600


is illustrated in FIG.


46


A. Referring to

FIG. 46A

, it will be seen that compressor


1600


is comprised of shaft


1602


on which is mounted rotor


1604


. The rotor


1604


is disk-shaped; air foils/vanes (not shown) are disposed at periphery


1606


of the rotor


1604


.




The rotor


1604


is disposed between suction side stator


1608


and discharge side stator


1610


. Intermediate stator


1612


also is disposed between suction side stator


1608


and discharge side stator


1610


.




Flow separator


1614


is attached to the inner diameter


1616


of the intermediate stator


1612


.




Rotor


1604


is comprised of a multiplicity of upstanding air foils which cause gas to flow in the direction of arrow


1618


, axially through the rotor


1604


, and then radially through discharge side stator


1610


and, thereafter in the direction of arrow


1620


, axially through the intermediate stator


1612


, and then radially through suction side stator


1608


.




The shaft


1602


is supported by bearings


1622


and


1624


as well as by roller bearing


1626


. A lip seal


1628


is disposed on the suction stator


1608


. Another lip seal


1630


is disposed on the discharge side stator


1610


. The lip seals are adapted to retain lubricant (not shown) within the bearing assemblies. Similarly, a drive shaft seal


1632


prevents lubricant and/or gas from leaking from the compressor


1600


.




A drive end cover


1634


is attached to the discharge stator side


1610


. An end plate/cover


1636


is attached to the suction side stator


1608


. A fastener


1638


holds the bearing assembly in place by means of washer


1640


. Positioning collar


1642


helps align the shaft


1602


.





FIG. 46B

is a side view of rotor


1604


. As will be seen, rotor


1604


is comprised of a multiplicity of vanes


1606


; only some of these vanes are shown in

FIG. 46B

for the sake of simplicity of representation.




The vanes


1606


are preferably disposed about the periphery of rotor


1604


in a manner which is substantially equidistant. Thus, if there are only four such vanes


1606


, there preferably will be one such vane per 90 degree quadrant. If there are 8 such vanes, there will be one such vane per 45 degree quadrant.




It is preferred that there be from about 20 to about 100 such vanes


1606


be disposed equidistantly around the periphery of rotor


1604


. The air foils


1606


preferably have a leading edge and a trailing edge defining an axial chord length therebetween, each of said airfoils, and they further comprise a convex suction surface and a concave pressure surface intersecting at said leading edge and said trailing edge, wherein each of said suction surfaces comprises an accelerating flow section and a decelerating flow section downstream of said accelerating flow section, wherein said first and said second adjacent airfoils define a throat between said trailing edge of said second airfoil and the nearest point on said suction surface of said first airfoil, and wherein said accelerating flow section of said first airfoil extends downstream of said throat. Such an airfoil is described, e.g., in U.S. Pat. No. 6,022,188, the entire disclosure of which is hereby incorporated by reference into this specification.




In the preferred embodiment depicted in

FIG. 46B

, the rotor


1604


preferably rotates clockwise, in the direction of arrow


1650


, as viewed the right side. The airfoils


1606


have a leading edge


1652


(on the suction side), a trailing edge


1654


(on the discharge side), and a configuration such that the distance


1656


between adjacent leading edges


1652


is smaller than the distance


1658


between adjacent trailing edges


1654


. Because of this differential in distance, there is a static pressure increase and a velocity decrease of gas between point


1660


and


1662


. Consequently, the gas being compressed will tend to flow axially in the direction of arrow


1664


.




The airfoils


1606


extend radially outwardly from the periphery of stator


1604


a distance which is about 30 percent or less than the radius of rotor


1604


. It is preferred that the airfoils extend outwardly a distance of less than about 10 percent of the radius of the rotor


1604


.




In the preferred embodiment depicted in

FIG. 46B

, each of airfoils


1606


has a substantially arcuate shape. In another embodiment, not shown, each of airfoils


1606


has a substantially non-arcuate shape.




The airfoils


1606


may be formed by conventional means. Thus, e.g., they may be cast in place, machined in place from a solid billet, or separately formed and then attached to the periphery of the rotor


1606


.





FIG. 46C

is a side view of suction side stator


1608


from which unnecessary detail has been omitted for the sake of simplicity of representation. Referring to

FIG. 46C

, it will be seen that suction side stator


1608


is comprised of intake port


1670


and opening


1672


. An arcuate channel is defined between points


1674


and


1676


and is formed in the surface of plate


1608


, and is open at the plane


1680


(see FIG.


46


A). Disposed within arcuate channel are a multiplicity of upstanding stator vanes


1678


which extend upwardly towards the plane


1680


of suction side stator plate (see

FIG. 46A

) from the bottom annular surface (not shown) of the channel. In another embodiment, not shown, the stator vanes


1678


are not orthogonal to the plane


1680


but, instead, are disposed at an acute or obtuse angle thereto.




The adjacent stator vanes


1678


form closed segments of the arcuate channel. The gas which is compressed may flow into the intake port


1670


and, initially, fills up entrance chamber


1682


; the gas flows inwardly towards the centerline


1679


of the driveshaft


1602


in the direction of arrow


1681


. Thereafter, the gas will flow in the direction of arrow


1683


within rotor


1604


, into a space between adjacent vanes/airfoils


1606


; during this portion of the gas flow, the gas will be flowing substantially axially. Thereafter, the gas will be introduced into the discharge side stator


1610


, in particular, into the entrance chamber of the discharge stator


1702


in the direction of arrow


1685


, which is radially outward from centerline


1679


of driveshaft


1602


. Thereafter, the gas will enter the intermediate stator


1612


into a space between stationary adjacent vanes/airfoils


1687


in the direction of arrow


1689


, substantially axially. Thereafter the gas will reenter the suction side stator


1608


.




As will be apparent to those skilled in the art, and referring to

FIG. 46C

, the gas flows helically through the assembly of the suction side stator


1608


, the rotor


1604


, the discharge side stator


1610


, and the intermediate stator


1612


(see

FIG. 46C

) from one vane compartment


1704


(see FIG.


46


C), to a second vane compartment


1706


(see FIG.


46


B), to a third vane compartment


1708


(see FIG.


46


E), to a fourth vane compartment


1710


(see FIG.


46


D), to a fifth vane compartment


1712


(see FIG.


46


C), to vane compartment


1714


in rotor


1604


(see FIG.


46


B), and then to vane compartment


1716


in intermediate stator


1612


(see FIG.


46


D), and then to vane


1718


in discharge side stator


1610


(see FIG.


46


E). This process is repeated until the gas flows through each of the vane compartments illustrated in

FIGS. 46B

,


46


C,


46


D, and


46


E and finally reaches exit chamber


1720


and thereafter discharges through discharge port


1722


(see FIG.


46


E).




As will be apparent those skilled in the art, as the gas flows around each vane and into the next succeeding vane compartment, the static pressure increases in accordance with Bernoulli's equation and the pressure consequently increases.




In the embodiment depicted in

FIG. 46C

, the vanes compartments are shown having substantially constant volumes and are separated by a distance


1724


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1726


, preferably decreasing from point


1728


to point


1730


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual increase in the gas pressure.




In the embodiment depicted in

FIG. 46C

, the vanes compartments are shown having substantially constant volumes and are separated by a distance


1732


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1734


, preferably decreasing from point


1736


to point


1738


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual increase in the gas pressure.




In the embodiment depicted in

FIG. 46E

, the vanes compartments are shown having substantially constant volumes and are separated by a distance


1740


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1742


, preferably decreasing from point


1744


to point


1746


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual substantially constant volumes and are separated by a distance


1724


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1726


, preferably decreasing from point


1728


to point


1730


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual increase in the gas pressure.




In the embodiment depicted in

FIG. 46C

, the vanes compartments are shown having substantially constant volumes and are separated by a distance


1732


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1734


, preferably decreasing from point


1736


to point


1738


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual increase in the gas pressure.




In the embodiment depicted in

FIG. 46E

, the vanes compartments are shown having substantially constant volumes and are separated by a distance


1740


which is preferably substantially the same between any two adjacent vanes; in this embodiment, the vane compartments are spaced substantially equidistantly from each other. In another embodiment, not shown, the vane spacing will vary as one proceeds in the direction of arrow


1742


, preferably decreasing from point


1744


to point


1746


, preferably in relationship to the decrease in specific volume. As will be apparent, this continual decrease in the vane spacing will cause an continual increase in the gas pressure.




The stator vanes


1678


are connected to an semi-annular plate


1608


which is disposed on the top of the arcuate closed channel and forms its top wall.





FIG. 47A

is schematic diagram of a power generation system


1800


. Referring to

FIG. 47A

, microturbine


456


generates direct current electrical power which is fed via line


1802


to motor controller


1804


, which controls the voltage supplied via line


1806


to direct current motor


1808


. A internal sensor


1810


monitors the speed of direct current motor


1808


and, when appropriate, feeds information via line


1812


to motor controller via feedback line


1814


to motor controller


1804


, which in turn either increases or decreases the speed of direct current motor


1808


. Direct current motor


1808


is connected via shaft


1816


to coupling


1818


which, in turn, drives shaft


1820


. Shaft


1820


is connected to alternating current generator


1822


. As will be apparent, by this system, a regulated alternating current output is produced which is fed via line


1824


.




The power generation system


1830


depicted in

FIG. 47B

is similar to that depicted in

FIG. 47A

with the exception that it contains a flywheel


1832


disposed on shaft


1816


and/or shaft


1820


. As will be apparent to those skilled in the art, the inertial mass presented by flywheel


1832


increases the regulation of the system and helps insure a more uniform alternating current output via line


1824


.




The power generation system


1850


depicted in

FIG. 47C

is similar to the device


1830


depicted in

FIG. 47B

with the exception that a battery pack


1852


is electrically connected via line


1854


to the output


1802


of microturbine assembly


456


. Microturbine assembly


456


frequently is called upon to start or stop when transient load demands are presented to the system. The inertia-imparting devices illustrated in

FIGS. 47B and 47C

help smooth out the operation of the microturbine


456


. As will be apparent, the battery pack


1852


provides electrical inertia in the same manner as the flywheel


1832


provides kinematic inertia.




The battery pack


1852


preferably provides direct current. In one embodiment, each battery cell in the battery pack provides 1.5 volt output. It is preferred that, in one embodiment, battery pack


1804


provides from about 250 to about 300 volts of direct current power.




The battery pack


1852


depicted in

FIG. 47C

may optionally also be used in the system of FIG.


47


A.




It is to be understood that the aforementioned description is illustrative only and that changes can be made in the apparatus, in the ingredients and their proportions, and in the sequence of combinations and process steps, as well as in other aspects of the invention discussed herein, without departing from the scope of the invention as defined in the following claims.



Claims
  • 1. A process for generating electricity, comprising:(a) feeding a mixture of gas and liquid at a pressure of from about 0.25 to about 50 pounds per square inch gauge to a compressor, (b) compressing said mixture of gas and liquid to a pressure of at least about 65 pounds per square inch gauge, thereby producing a mixture comprised of compressed gas and liquid, (c) feeding said mixture comprised of said compressed gas and liquid to an accumulator/separator in which liquid material and solid material is removed from said mixture of compressed gas and liquid, thereby producing a first purified mixture of gas and liquid, (d) feeding said first purified mixture of gas and liquid to a coalescent filter in which liquid material is removed from said first purified mixture of gas and liquid, thereby producing a second purified gas, (e) feeding said second purified gas to a pressure regulator and reducing the pressure of said second purified gas, thereby producing a reduced pressure second purified gas, (f) feeding said reduced pressure second purified gas to a microturbine, (g) combusting said reduced pressure second purified gas in said microturbine, thereby producing a first direct current in a first electrical line, and (h) feeding said first direct current to a direct current motor and causing said direct current motor to rotate, and (i) driving an generator with said direct current motor and producing alternating current from said generator.
  • 2. The process as recited in claim 1, wherein said accumulator/separator is comprised of a baffle for disrupting the flow of said mixture of compressed gas and liquid.
  • 3. The process as recited in claim 2, wherein said baffle is in the shape of a truncated cone.
  • 4. The process as recited in claim 2, wherein said accumulator/separator is comprised of means for introducing said mixture of compressed gas and liquid into said accumulator/separator in a tangential manner.
  • 5. The process as recited in claim 2, wherein said accumulator/separator is comprised of perforated plate which disrupts the flow of said compressed gas and liquid through said accumulator/separator.
  • 6. The process as recited in claim 5, wherein said accumulator/separator is comprised of a vent stack.
  • 7. The process as recited in claim 6, wherein filtering material is disposed within said vent stack.
  • 8. The process as recited in claim 7, wherein said filtering material is steel mesh.
  • 9. The process as recited in claim 7, wherein said filtering material is steel wool.
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation-in-part of applicants' patent application U.S. Ser. No. 09/672,804, filed on Sep. 28, 2000, which was a continuation-in-part of patent application U.S. Ser. No. 09/536,332, filed on Mar. 24, 2000, now U.S. Pat. No. 6,266,952, which was a continuation-in-part of copending patent application U.S. Ser. No. 09/416,291, filed on Oct. 14, 1999, which was a continuation-in-part of patent application U.S. Ser. No. 09/396,034, filed on Sep. 15, 1999, now U.S. Pat. No. 6,301,898, which in turn was a continuation-in-part of patent application U.S. Ser. No. 09/181,307, filed on Oct. 28, 1998, abandoned. This application is also a continuation-in-part of applicant's patent application U.S. Ser. No. 09/441,312, filed on Nov. 16, 1999 now U.S. Pat. No. 6,213,744.

US Referenced Citations (2)
Number Name Date Kind
2192885 Avery Mar 1940 A
5165236 Nieminen Nov 1992 A
Continuation in Parts (6)
Number Date Country
Parent 09/672804 Sep 2000 US
Child 09/775292 US
Parent 09/536332 May 2000 US
Child 09/672804 US
Parent 09/441312 Nov 1999 US
Child 09/536332 US
Parent 09/416291 Oct 1999 US
Child 09/441312 US
Parent 09/396034 Sep 1999 US
Child 09/416291 US
Parent 09/181307 Oct 1998 US
Child 09/396034 US