Embodiments of the disclosure generally relate to a unitary and compact packaging configuration for a supersonic ejector system.
Ejectors, sometimes called gas or steam ejectors or venturi ejectors, are generally known in the art. They are commonly used to maintain a vacuum or to compress a gas. The advantage of the ejector over conventional mechanical pumps, such as piston pumps or compressors and diaphragm pumps, is that ejectors have no moving parts and are generally robust (subject to filtering the gas streams to reduce pitting and corrosion). Typically ejectors are subsonic, as supersonic ejectors tend to produce a low pressure exit stream. Additionally supersonic ejectors are generally more sensitive to design/construction parameters for proper operation.
An ejector typically includes an expansion nozzle port through which a motive gas enters the ejector via an inlet port. The gas is expanded to a lower pressure as it passes through a constricted throat section of the expansion nozzle. Generally there is a suction port opening into an enclosed chamber about the expansion nozzle through which the gas to be captured is drawn into the ejector by the pressure differential. Then downstream of the expander there is generally a diffuser section having an inlet, a throat section, and a diverging discharge section.
Conventional subsonic ejectors are commonly used to maintain a vacuum on a system such as disclosed in the following patents: U.S. Pat. No. 5,380,822 discloses the use of a gas, typically steam, ejector to maintain a lower pressure in the later stages of a falling strand devolatilizer than in the down stream condenser to prevent water from freezing; U.S. Pat. No. 6,855,248 teaches the use of a steam ejector to maintain a vacuum on a processing column; U.S. Pat. No. 6,330,821 teaches the use of a gas ejector to maintain a vacuum on a part being tested; U.S. Pat. No. 4,194,924 teaches distilling a carrier solvent and JP-4 in a heated vacuum column in which the vacuum is provided by a gas (steam) ejector; and U.S. Pat. No. 4,834,343 teaches a non flooded treatment column including a venturi device within the top of the column to re-disperse the gas beneath the fluid level. Each of the aforementioned patents is hereby incorporated by reference in their entirety into the present disclosure, to the extent that the aforementioned patents are not inconsistent with the present disclosure.
However, one challenge with the prior art disclosures is the packaging of the ejector systems. More particularly, Applicants have licensed the technology embodied in U.S. patent application Ser. No. 11/809,342 entitled Tandem Supersonic Ejectors (the “'342 application”), which is hereby incorporated by reference in its entirety into the present application. However, in implementing the technology of the '342 application, Applicants have encountered several challenges associated with the size and packaging of the tandem supersonic ejectors. As with the other prior art ejectors noted above, the '342 tandem ejector system is bulky and not desirable for field implementation. As such, there is a need for an efficient, compact, and cost effective supersonic ejector system packaging that is manufactured from a unitary housing, casing, or metal block.
Embodiments of the disclosure may generally provide a tandem supersonic ejector system packaged in a compact unitary housing.
Embodiments of the disclosure may further provide a tandem supersonic ejector system packaged in a unitary housing. The system may include a first supersonic ejector that receives a compressor discharge at a high pressure input and a compressor gas seal vent line at a low pressure input. A second supersonic ejector may be configured to receive the compressor discharge pressure at a high pressure input and receive the output of the first supersonic ejector at the low pressure input to the second ejector. The output of the second ejector may be communicated to a gas turbine fuel system after being passed through a fuel regulator. Both the first and second supersonic ejectors are contained in a unitary housing that may include a block of metal or alloy material that has been milled, drilled, or otherwise machined to receive the ejectors and associated conduits therein. The resulting size of the block of metal containing the ejectors will generally be about 12×12×5 inches.
Embodiments of the disclosure may further provide a tandem supersonic ejector system that includes a block of metal or an alloy that has a first bore formed there through, where the first bore extends substantially through the block and is sized to receive a first ejector therein. The block further includes a second bore formed therein, where a first end of the second bore originates proximate an outer edge of the block and a second end of the second bore terminates proximate the first bore and is in communication therewith. The second bore may be sized to receive a second supersonic ejector therein. The originating ends of the bores for the first and second ejectors may include fittings threadably secured to the block, and where the fittings are configured to engage pipe flanges. With regard to the block, the length and width of the block may be between about 8 inches and about 16 inches, and the height between about 2½ inches and about 6½ inches.
Embodiments of the disclosure may further provide a supersonic ejector assembly. The assembly may include a housing manufactured from a solid piece of material, a first ejector assembly positioned in a first bore formed in the housing and secured therein by a first input side flange positioned over an input end of the first bore and an output side flange positioned over an output end of the first bore, and a second ejector assembly positioned in a second bore formed in the housing and secured therein by a second input side flange positioned over an input end of the second bore, the second bore terminating into the first bore proximate a suction input of the first ejector assembly.
Embodiments of the disclosure may further provide a tandem supersonic ejector package that includes a first supersonic ejector assembly positioned in a first bore formed into a unitary housing, and a second supersonic ejector assembly positioned in a second bore formed into the unitary housing, wherein an output of the second supersonic ejector assembly is in communication with a suction input of the first supersonic ejector assembly.
Embodiments of the disclosure may further provide a tandem supersonic ejector package. The package may include a unitary metal or metal alloy block having the following bores formed therein: a first longitudinal bore formed through the block; a second longitudinal bored formed into the block and terminating into the first longitudinal bore; and a third longitudinal bore formed into the block and terminating into the second longitudinal bore. The package may further include a first supersonic ejector assembly positioned in the first longitudinal bore, and a second supersonic ejector assembly positioned in the second longitudinal bore, wherein a suction input of the first supersonic ejector assembly is in communication with terminating end of the second longitudinal bore, and a suction input of the second supersonic ejector assembly is in communication with the terminating end of the third longitudinal bore.
The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure provides several exemplary embodiments for implementing different features, structures, or functions of the disclosure. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure, however, these exemplary embodiments are provided merely as examples and are not intended to be limiting on the scope of the disclosure. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one embodiment may be used in any other embodiment, without departing from the intent of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to be limiting upon the scope of the disclosure, unless otherwise specifically defined herein. Further, the naming convention used herein is not intend to distinguish between components that differ in name but not function. Further, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope of the disclosure.
The end of the diffuser 18 exits into a conduit 16 leading to an enclosure 21, which is air tight or substantially air tight, that includes a suction port 22 of the second supersonic ejector 20. The suction port 22 of the second supersonic ejector 20 may be annular. The motive gas enters a nozzle 27 of the second supersonic ejector 20 and proceeds to a constricted throat 23, is expanded through the diverging section of the nozzle 27 and exits the nozzle 27 at an exit 29 and proceeds to diffuser 28 having a larger throat 24 than throat 23 of nozzle 27. The cross sectional area of the channel through the second supersonic ejector 20 also increases in size from throat 23 of the nozzle 27 to the throat 24 of the diffuser 28. This increases the velocity of the motive gas as it passes through throat 23 and the diverging section of the nozzle 27 and reduces the pressure drawing the exit gas from the first supersonic ejector 10 passing through the conduit 16 into the ejector 20 through suction port 22. Due to the converging and diverging cross section areas of the channel through the diffuser the speed of the motive gas and entrained off gas decreases in the diffuser. The mixture of the motive gas and the gas in the conduit 16 exits the ejector 20 at a discharge end 25 of the diffuser 28. The discharge end 25 of the diffuser 28 of the second supersonic ejector 20 feeds a conduit, which may be a pipe or other gas communicating line to recirculate the off gas combined with the motive gas for further processing.
In operation a motive gas at a higher pressure than the off gas, in the case of a pipeline the natural gas within the line, and in the case of a chemical plant the process steam, is injected into the nozzle 17 of the first supersonic ejector 10. The cross sectional area of the ejector 10 narrows to a throat section 13 of the first supersonic ejector 10. This increases the velocity of the gas as it passes through the throat 13 and continues to expand through the diverging section of the nozzle 17 to the exit 19, which creates a lower pressure at the suction inlet 12 of the first supersonic ejector 10. This draws the off gas within the enclosure 11 into the first supersonic ejector. The off gas is drawn into and entrained with the motive gas passing through the first supersonic ejector 10. Downstream the cross sectional area of the throat 14 of the diffuser 18 is larger than the throat 13 of the nozzle 17. The diffuser 18 expands to the discharge end 15 or is fed to the suction port 22 for the second supersonic ejector 20. A second motive gas is fed to the nozzle 27 of the second supersonic ejector 20, which narrows to the throat 23. The gas velocity increases and the pressure drops drawing the off gas into the nozzle and leaves at the exit 29. The cross sectional area of the second supersonic ejector 20 also increases to the throat 24 of the diffuser 28 and then further expands to the discharge end 25. The discharge end 25 then feeds a line (not shown) which directs the recompressed off gas to subsequent processing at a higher pressure.
In another exemplary embodiment of the disclosure, the nozzles 17 and 27 of the supersonic ejectors 10, 20 are adjustable relative to the diffusers 18 and 28. Typically this is done by having the nozzle 17, 27 threaded and mounted on receiving threads on the enclosure or on a portion of the inlet to the diffuser 18, 28 in a manner not to close the suction port. The ejectors 10, 20 may be designed so that the first supersonic ejector 10 is operated at an exit Mach number from about 2.4 to about 2.6 and the second supersonic ejector 20 is operated at an exit Mach number from about 1.6 to about 1.8. In the first supersonic ejector 10, the ratio of the cross section area of the nozzle exit 19 to the nozzle throat 13 may be from about 2.9 to about 3.2, preferably from about 3.0 to about 3.1. In the second supersonic ejector 20, the ratio of the cross section area of the nozzle exit 29 to the nozzle throat 23 may be from about 1.30 to about 1.45, preferably from about 1.35 to about 1.40. The ratio of the area of the throat 14 of the diffuser 18 to the throat 13 of the nozzle 17 of the first supersonic ejector 10 may range from about 4.60 to about 4.90, preferably from 4.70 to 4.80. The ratio of the area of the throat 24 of the diffuser 28 to the throat 23 of the nozzle 27 of the second supersonic ejector 20 may range from about 1.70 to about 1.90, preferably from about 1.80 to about 1.90. Typically the ratio of the motive gas flow rate to the first supersonic gas ejector to the off gas flow rate is from about 32 to about 45. (e.g. either g per g or Kg per Kg as this is a unitless ratio). Typically the ratio between the motive gas flow rate to the second supersonic gas ejector and the discharge flow from the first supersonic ejector is from about 20 to about 25.
Without being bound by theory, the one-dimensional governing equations for the isentropic expansion of gas through a converging-diverging supersonic nozzle can be written as shown in U.S. patent application Ser. No. 11/809,342 (the “'342 application”). Additionally, FIG. 2 of the '342 application illustrates Mach number contours at the exit of a supersonic nozzle and diffuser; FIG. 3 of the '342 application illustrates Stagnation Pressure Contours at Exit of Supersonic Nozzle and Diffuser; FIG. 4 of the '342 application illustrates the overall performance of the two-Stage Supersonic Ejector, FIG. 5 of the '342 application illustrates overall performance of the two-Stage Supersonic Ejector; and FIG. 6 of the '342 application illustrates overall performance of the two-Stage Supersonic Ejector. Each of these Figures and the accompanying description are hereby incorporated by reference into the present disclosure, to the extent that the incorporated subject matter is not inconsistent with the present disclosure.
In another exemplary embodiment, the tandem supersonic ejector systems can be combined with other ejector systems, including other tandem ejector systems, to form a series or chain of ejector systems. In other embodiments of the disclosure, the number of ejectors in the system may be increased to 3, 4, 5, or more ejectors in a similar configuration as disclosed in at least one of the embodiments presented herein. Thus, the tandem configuration may be expanded to include between 3 and about 6 or more supersonic ejectors.
In each of the exemplary ejector systems illustrated in
Referring still to the exemplary system 500 illustrated in
In each of the above noted exemplary embodiments, the ejector assemblies may be manufactured from a metal or metal alloy. The metal or metal alloy may be selected for the specific application, i.e., for temperature, strength, or chemical reactivity considerations that accompany each application. Regardless, exemplary materials that may be used to manufacture the ejector assemblies include metals, iron, steel, titanium, and various alloys of these materials with additional elements added thereto. In at least one exemplary embodiment the ejectors may be manufactured from a non-metallic material, such as a ceramic or other rigid non-metallic material. Similarly, the housing may also be manufactured from the same exemplary materials as the ejector assemblies. However, in selecting the appropriate material for the respective elements, the ability of the material to be precisely machined is a primary factor.
Embodiments of the disclosure may generally provide a tandem supersonic ejector system. The system may include a first supersonic ejector that receives a compressor discharge at a high pressure input and a compressor gas seal vent line at a low pressure input. A second supersonic ejector may be configured to receive the compressor discharge pressure at a high pressure input and receive the output of the first supersonic ejector at the low pressure input to the second ejector. The output of the second ejector may be communicated to a gas turbine fuel system after being passed through a fuel regulator. Both the first and second supersonic ejectors are contained in a unitary housing that comprises a block of metal that has been milled or drilled to receive the ejectors therein. The resulting size of the block of metal containing the ejectors will generally be about 12×12×5 inches.
Embodiments of the disclosure may further provide a tandem supersonic ejector system that includes a block of metal or an alloy that has a first bore formed therethrough, where the first bore extends substantially through the block and is sized to receive a first ejector therein. The block further includes a second bore formed therein, where a first end of the second bore originates proximate an outer edge of the block and a second end of the second bore terminates proximate the first bore and is in communication therewith. The second bore may be sized to receive a second supersonic ejector therein. The originating ends of the bores for the first and second ejectors may include fittings threadably secured to the block, and where the fittings are configured to engage pipe flanges. With regard to the block, the length and width of the block may be between about 8 inches and about 16 inches, and the height between about 2½ inches and about 6½ inches.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.
This application claims the benefit of the filing date of U.S. Patent Application Ser. No. 61/095,409, filed Sep. 9, 2008, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
61095409 | Sep 2008 | US |