Patent Application
20110255961
The subject matter disclosed herein relates to a pump for a solid, such as particulate matter.
A typical pump designed for solids, such as particulate matter, has a single continuous channel. For example, the pump may be a rotary pump that drives the solids along a circular path. Thus, the rotary pump has stationary and rotating components that interface with one another. Unfortunately, the flow of solids at the inlet and outlet of the pump may cause high stresses and friction between the stationary and rotating components of the pump, thereby causing high heat generation in the pump.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
In a first embodiment, a system includes a solid fuel pump. The solid fuel pump includes a housing, a rotor disposed in the housing; a curved passage disposed between the rotor and the housing, an inlet port coupled to the curved passage, an outlet port coupled to the curved passage, a solid fuel guide extending across the curved passage, and a first roller at an interface between the solid fuel guide and the rotor.
In a second embodiment, a system includes a solid feed pump. The solid feed pump includes a housing, a rotor disposed in the housing, a curved passage disposed between the rotor and the housing, an inlet port coupled to the curved passage, an outlet port coupled to the curved passage, a solid feed guide extending across the curved passage, and multiple discrete contacts distributed along an interface between the solid feed guide and the rotor.
In a third embodiment, a system includes a solid feed pump. The solid feed pump includes a housing, a rotor disposed in the housing, a curved passage disposed between the rotor and the housing, an inlet port coupled to the curved passage, an outlet port coupled to the curved passage, a solid feed guide extending across the curved passage, and a discrete static contact at an interface between the solid feed guide and the rotor.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
Embodiments of the present disclosure include a solid feed pump with a solid feed guide at an inlet and/or outlet, wherein the solid feed guide includes unique features to increase support, reduce friction, reduce stresses, and reduce heat generation at an interface between the solid feed guide and a rotor. As discussed in detail below, the unique features may include one or more static or movable contacts at the interface between the solid feed guide and the rotor. For example, the contacts may include curved protrusions, such as semi-spherical, cylindrical, or convex protrusions, at discrete points between the solid feed guide and the rotor. By further example, the contacts may include rollers, such as cylindrical or spherical rollers. In certain embodiments, the contacts are disposed directly between the solid feed guide and the rotor, whereas other embodiments position the contacts at an offset from the interface. In each of the disclosed embodiments, the contacts reduce friction, wear, heat generation, and stresses at the interface.
The IGCC system 100 produces and burns a synthetic gas, i.e., syngas, to generate electricity. Elements of the IGCC system 100 may include a fuel source 102, such as a solid feed, that may be utilized as a source of energy for the IGCC. The fuel source 102 may include coal, petroleum coke, biomass, wood-based materials, agricultural wastes, tars, asphalt, or other carbon containing items. The solid fuel of the fuel source 102 may be passed to a feedstock preparation unit 104. The feedstock preparation unit 104 may, for example, resize or reshape the fuel source 102 by chopping, milling, shredding, pulverizing, briquetting, or palletizing the fuel source 102 to generate a dry feedstock (e.g., particulate matter).
In the illustrated embodiment, the solid feed pump 10 delivers the feedstock from the feedstock preparation unit 104 to a gasifier 106. The solid feed pump 10 may be configured to meter and pressurize the fuel source 102 received from the feedstock preparation unit 104. The gasifier 106 may convert the feedstock into a syngas, e.g., a combination of carbon monoxide and hydrogen. This conversion may be accomplished by subjecting the feedstock to a controlled amount of steam and oxygen at elevated pressures, e.g., from approximately 20 bar to 85 bar, and temperatures, e.g., approximately 700 degrees Celsius to 1600 degrees Celsius, depending on the type of gasifier 106 utilized.
The gasification process may include the feedstock undergoing a pyrolysis process, whereby the feedstock is heated. Temperatures inside the gasifier 106 may vary during the pyrolysis process, depending on the fuel source 102 utilized to generate the feedstock. The heating of the feedstock during the pyrolysis process may generate a solid, (e.g., char), and residue gases, (e.g., carbon monoxide, hydrogen, and nitrogen). The char remaining from the feedstock from the pyrolysis process may only weigh up to approximately 30% of the weight of the original feedstock.
A partial oxidation process may then occur in the gasifier 106. The combustion may include introducing oxygen to the char and residue gases. The char and residue gases may react with the oxygen to form carbon dioxide and carbon monoxide, which provides heat for the gasification reactions. The temperatures during the partial oxidation process may range from approximately 700 degrees Celsius to 1600 degrees Celsius. Steam may be introduced into the gasifier 106 during gasification. The char may react with the carbon dioxide and steam to produce carbon monoxide and hydrogen at temperatures ranging from approximately 800 degrees Celsius to 1100 degrees Celsius. In essence, the gasifier utilizes steam and oxygen to allow some of the feedstock to be “burned” to produce carbon monoxide and release energy, which drives a second reaction that converts further feedstock to hydrogen and additional carbon dioxide.
In this way, a resultant gas is manufactured by the gasifier 106. This resultant gas may include approximately 85% of carbon monoxide and hydrogen in equal proportions, as well as CH4, HCl, HF, COS, NH3, HCN, and H2S (based on the sulfur content of the feedstock). This resultant gas may be termed untreated, raw, or sour syngas, since it contains, for example, H2S. The gasifier 106 may also generate waste, such as slag 108, which may be a wet ash material. This slag 108 may be removed from the gasifier 106 and disposed of, for example, as road base or as another building material. Prior to cleaning the raw syngas, a syngas cooler 107 may be utilized to cool the hot syngas. The cooling of the syngas may generate high pressure steam which may be utilized to produce electrical power as described below. After cooling the raw syngas, a gas cleaning unit 110 may be utilized to clean the raw syngas. The gas cleaning unit 110 may scrub the raw syngas to remove the HCl, HF, COS, HCN, and H2S from the raw syngas, which may include separation of sulfur 111 in a sulfur processor 112 by, for example, an acid gas removal process in the sulfur processor 112. Furthermore, the gas cleaning unit 110 may separate salts 113 from the raw syngas via a water treatment unit 114 that may utilize water purification techniques to generate usable salts 113 from the raw syngas. Subsequently, the gas from the gas cleaning unit 110 may include treated, sweetened, and/or purified syngas, (e.g., the sulfur 111 has been removed from the syngas), with trace amounts of other chemicals, e.g., NH3 (ammonia) and CH4 (methane).
A gas processor 116 may be utilized to remove residual gas components 117 from the treated syngas such as, ammonia and methane, as well as methanol or any residual chemicals. However, removal of residual gas components 117 from the treated syngas is optional, since the treated syngas may be utilized as a fuel even when containing the residual gas components 117, e.g., tail gas. At this point, the treated syngas may include approximately 3% CO, approximately 55% H2, and approximately 40% CO2 and is substantially stripped of H2S. This treated syngas may be transmitted to a combustor 120, e.g., a combustion chamber, of a gas turbine engine 118 as combustible fuel. Alternatively, the CO2 may be removed from the treated syngas prior to transmission to the gas turbine engine.
The IGCC system 100 may further include an air separation unit (ASU) 122. The ASU 122 may operate to separate air into component gases by, for example, distillation techniques. The ASU 122 may separate oxygen from the air supplied to it from a supplemental air compressor 123, and the ASU 122 may transfer the separated oxygen to the gasifier 106. Additionally the ASU 122 may transmit separated nitrogen to a diluent nitrogen (DGAN) compressor 124.
The DGAN compressor 124 may compress the nitrogen received from the ASU 122 at least to pressure levels equal to those in the combustor 120, so as not to interfere with the proper combustion of the syngas. Thus, once the DGAN compressor 124 has adequately compressed the nitrogen to a proper level, the DGAN compressor 124 may transmit the compressed nitrogen to the combustor 120 of the gas turbine engine 118. The nitrogen may be used as a diluent to facilitate control of emissions, for example.
As described previously, the compressed nitrogen may be transmitted from the DGAN compressor 124 to the combustor 120 of the gas turbine engine 118. The gas turbine engine 118 may include a turbine 130, a drive shaft 131 and a compressor 132, as well as the combustor 120. The combustor 120 may receive fuel, such as syngas, which may be injected under pressure from fuel nozzles. This fuel may be mixed with compressed air as well as compressed nitrogen from the DGAN compressor 124, and combusted within combustor 120. This combustion may create hot pressurized exhaust gases.
The combustor 120 may direct the exhaust gases towards an exhaust outlet of the turbine 130. As the exhaust gases from the combustor 120 pass through the turbine 130, the exhaust gases force turbine blades in the turbine 130 to rotate the drive shaft 131 along an axis of the gas turbine engine 118. As illustrated, the drive shaft 131 is connected to various components of the gas turbine engine 118, including the compressor 132.
The drive shaft 131 may connect the turbine 130 to the compressor 132 to form a rotor. The compressor 132 may include blades coupled to the drive shaft 131. Thus, rotation of turbine blades in the turbine 130 may cause the drive shaft 131 connecting the turbine 130 to the compressor 132 to rotate blades within the compressor 132. This rotation of blades in the compressor 132 causes the compressor 132 to compress air received via an air intake in the compressor 132. The compressed air may then be fed to the combustor 120 and mixed with fuel and compressed nitrogen to allow for higher efficiency combustion. Drive shaft 131 may also be connected to load 134, which may be a stationary load, such as an electrical generator for producing electrical power, for example, in a power plant. Indeed, load 134 may be any suitable device that is powered by the rotational output of the gas turbine engine 118.
The IGCC system 100 also may include a steam turbine engine 136 and a heat recovery steam generation (HRSG) system 138. The steam turbine engine 136 may drive a second load 140. The second load 140 may also be an electrical generator for generating electrical power. However, both the first and second loads 134, 140 may be other types of loads capable of being driven by the gas turbine engine 118 and steam turbine engine 136. In addition, although the gas turbine engine 118 and steam turbine engine 136 may drive separate loads 134 and 140, as shown in the illustrated embodiment, the gas turbine engine 118 and steam turbine engine 136 may also be utilized in tandem to drive a single load via a single shaft. The specific configuration of the steam turbine engine 136, as well as the gas turbine engine 118, may be implementation-specific and may include any combination of sections.
The IGCC system 100 may also include the HRSG 138. High pressure steam may be transported into the HSRG 138 from the syngas cooler 107. Also, heated exhaust gas from the gas turbine engine 118 may be transported into the HRSG 138 and used to heat water and produce steam used to power the steam turbine engine 136. Exhaust from, for example, a low-pressure section of the steam turbine engine 136 may be directed into a condenser 142. The condenser 142 may utilize a cooling tower 128 to exchange heated water for chilled water. The cooling tower 128 acts to provide cool water to the condenser 142 to aid in condensing the steam transmitted to the condenser 142 from the steam turbine engine 136. Condensate from the condenser 142 may, in turn, be directed into the HRSG 138. Again, exhaust from the gas turbine engine 118 may also be directed into the HRSG 138 to heat the water from the condenser 142 and produce steam.
In combined cycle systems such as IGCC system 100, hot exhaust may flow from the gas turbine engine 118 and pass to the HRSG 138, along with the steam generated by the syngas cooler 107, where it may be used to generate high-pressure, high-temperature steam. The steam produced by the HRSG 138 may then be passed through the steam turbine engine 136 for power generation. In addition, the produced steam may also be supplied to any other processes where steam may be used, such as to the gasifier 106. The gas turbine engine 118 generation cycle is often referred to as the “topping cycle,” whereas the steam turbine engine 136 generation cycle is often referred to as the “bottoming cycle.” By combining these two cycles as illustrated in
As mentioned above, the IGCC system 100 may include one or more solid feed pumps 10.
As particulate matter is fed through an opening 230 of the inlet 200, the solid feed pump 10 may impart a tangential force or thrust to the particulate matter in the rotational direction 216 of the rotor 204. The direction of flow 234 of the particulate matter is from the inlet 200 to the outlet 202. As the particulate matter rotates through the curved passage 210, the particulate matter encounters the guide wall 222 of the solid feed guide 212 disposed adjacent the outlet 202 extending across the curved passage 210. The particulate matter is diverted by the solid feed guide 212 through an opening 236 of the outlet 202 into an exit pipe 238 connected to a high pressure vessel or into a conveyance pipe line.
The guide wall 222 may substantially block the curved passage 210. In some embodiments, the guide wall 222 may only partially block the curved passage 210. The guide wall 222 extends radially outward from the rotor 204. The guide wall 222 may be angled in a radial direction relative to the rotor 204. For example, the radial angle (i.e., angle between guide wall 222 and the rotor 204) may range between approximately 0 to 90 degrees, 0 to 60 degrees, 30 to 60 degrees, 0 to 45 degrees, 30 to 45 degrees, 0 to 30 degrees, or 0 to 15 degrees, or any angle therebetween. By further example, the radial angle may be approximately 30, 35, 40, 45, 50, 55, or 60 degrees, or any angle therebetween.
The impact of the particulate matter on the solid feed guide 212 may create a load pressure on the guide wall 222. The load pressure may increase the sliding friction between the rotor interfacing surface 224 and the outer surface 226 of the rotor 204. The increase in friction may result in an increase in heat generation at the rotor interfacing surface 224 near the tip 228 of the solid feed guide 212. Besides increasing friction, the load pressure created by the particulate matter on the solid feed guide 212 may increase the high stresses experienced by the solid feed guide 212, particularly at the tip 228. Together, the high heat generation and the high stresses may accelerate the rate of tip wear. However, as discussed below, the disclosed embodiments include one or more discrete contacts at the surfaces 224 and 226 to reduce friction, heat generation, and stresses.
The illustrated multiple discrete contacts 250 are movable. For example, the multiple discrete contacts 250 may roll in the rotational direction 216 of the rotor 204. In addition, the multiple discrete contacts 250 may be made of a low-friction material and have a rolling friction coefficient less than the sliding friction coefficient experienced by the rotor interfacing surface 224 in the absence of the multiple discrete contacts 250. For example, the low-friction material may include high alloy steel, stainless steel, chrome steel, ceramic, plastic, or a combination thereof. Thus, the multiple discrete contacts 250 may generate less heat and may reduce the total heat generated between the solid feed guide 212 and the rotor 204. Besides reducing friction, the multiple discrete contacts 250 may provide extra support to the lower portion 220 of the solid feed guide 212, particularly the rotor interfacing surface 224. As a result of this additional support, the high stresses experienced by the lower portion 220 of the solid feed guide 212 may be reduced, particularly the stresses near the tip 228. Other embodiments may include both movable and static discrete contacts 250.
In some embodiments, the multiple discrete contacts 250 may be stationary.
As mentioned above in
Alternatively, the bearings 270 may include ball bearings 300.
In certain embodiments, the multiple discrete contacts 250 may include wheels or rollers having a rotational axis or axle.
In some embodiments, the movable discrete contacts 250 may not be located directly on the rotor interfacing surface 224 of the solid feed guide 212.
As illustrated, the extension 330 may originate from the lower portion 220 of the backside 332 of the solid feed guide 212. In other embodiments, the extension 330 may originate from the upper portion 218 of the solid feed guide 212. The extension 330 may be angled in a radial direction relative to the backside 332 of the solid feed guide 212. For example, the radial angle (i.e., angle between the extension 330 and the backside 332 of solid feed guide 212) may range between about 0 to 90 degrees, 0 to 60 degrees, 30 to 60 degrees, 0 to 45 degrees, 30 to 45 degrees, 0 to 30 degrees, or 0 to 15 degrees. By further example, the radial angle may be about 30, 35, 40, 45, 50, 55, 60 or 65 degrees, or any angle therebetween.
The movable discrete contact 250 located on the backside 332 of the solid feed guide 212 may provide additional support to the solid feed guide 212 to reduce stresses experienced by the lower portion 220 of the solid feed guide 212, particularly the tip 228. Additionally, the backside 332 location of the movable discrete contact 250 may allow a thickness 334 of the solid feed guide 212 to be reduced from a thickness 336 of the standard solid feed guide 212. In certain embodiments, the thickness 334 of the backside supported solid feed guide 212 may be reduced by at least approximately 10, 20, 30, 40, or 50 percent compared to the thickness 336 of the standard solid feed guide 212. For example, the thickness 336 of the standard solid feed guide 212 may be a factor of approximately 1.1 to 3 times greater than the thickness 334 of the backside supported solid feed guide 212. However, the factor may range between approximately 1 to 3, 1 to 2.5, 1 to 2, or 1 to 1.5. The reduced thickness of the solid feed guide 212 may reduce the area requiring a tight tolerance between the rotor interfacing surface 224 and the outer surface 226 of the rotor 204.
In additional embodiments, the movable discrete contacts 250 may be adjustable at the interface between surfaces 224 and 226.
As mentioned above, a tight tolerance is provided between the solid feed guide 212 and the rotor 204 for efficient operation of the solid feed pump 10. The adjustable movable discrete contacts 250 may help ensure this tight tolerance. The adjustable movable discrete contacts 250 may allow the proper clearance to be obtained between the solid feed guide 212 and the rotor 204 during initial installation. Also, as the movable discrete contacts 250 wear over time, the clearance between the solid feed guide and the rotor may be adjusted to ensure a tight tolerance.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
