METHOD FOR THE CAPTURE OF CARBON DIOXIDE THROUGH CRYOGENICALLY PROCESSING GASEOUS EMISSIONS FROM FOSSIL-FUEL POWER GENERATION

Abstract

A cryogenic method for capturing carbon dioxide in the gaseous emissions produced from the fossil-energy combustion of solid, liquid, or gaseous fossil fuels in a power generation installation employing an OxyFuel mode of combustion. The method includes: producing essentially pure carbon dioxide under elevated pressure and at near ambient temperatures in a Carbon-Dioxide Capture Component from the carbon-dioxide content of at least a part of the gaseous emissions produced from fossil-energy fueled combustion in the Oxyfuel mode of combustion; separating atmospheric air in an Air Separation Component into a stream of liquid nitrogen and a stream of high-purity oxygen; supplying low temperature, compressed purified air to a cryogenic air separation unit (cold box) within the Air Separation Component; collecting low temperature thermal energy from coolers employed within the Carbon-Dioxide Capture Component and the Air Separation Component; and converting the collected thermal energy to electricity within a Thermal-Energy Conversion Component.

Claims

1-21. (canceled)

22. (canceled)

23. (canceled)

24. The method of claim 42 including driving turbo-compressors within the carbon dioxide capture component with steam supplied from the power generation installation operating in an OxyFuel combustion mode.

25. The method of claim 42 including driving turbo-compressors within the air separation component with steam supplied from the power generation installation operating in an OxyFuel combustion mode.

26. The method of claim 42 including: pre-cooling the gaseous emissions from the power generation installation produced by OxyFuel mode combustion of fossil fuel in the carbon dioxide capture component by heat exchange with the upper refrigerant supplied by the thermal energy conversion component, wherein the gaseous emissions are partially dried by cooling to a temperature at which their water vapor content condenses and the condensate is separated; and, feeding the partially dried gaseous emissions to a first stage of multistage turbo-compression in the carbon dioxide capture component.

27. The method of claim 42 including: pre-cooling the atmospheric air input into the air separation component by heat exchange with the upper refrigerant supplied by the thermal energy conversion component wherein the atmospheric air is partially dried and cooled to a temperature at which water vapor content within the atmospheric air condenses and separates; and feeding the atmospheric air after being partially dried to a first stage of the multistage compression in the air separation component.

28. The method of claim 42 including: reducing the temperature of the gaseous emissions from the power generation installation received by the carbon dioxide capture component by the upper refrigerant; and simultaneously reducing the temperature of the atmospheric air received by the air separation component by the upper refrigerant to a level above the freezing temperature of water.

29. The method of claim 42 including; reducing the pressure of the tail gas separated within the carbon dioxide capture component by isolating as liquid carbon dioxide to the liquid carbon-dioxide so far captured in the carbon dioxide capture component.

30. The method of claim 42 including; reducing the pressure of the tail gas produced within the carbon dioxide capture component to isolate its carbon dioxide content as a solid carbon dioxide snow; and adding the solid carbon dioxide snow, after vaporization under pressure, to the carbon dioxide so far captured in the carbon dioxide capture component.

31. The method of claim 30 including adding the processed tail gas, after extracting recoverable carbon dioxide, to the stream of atmospheric air entering a compressed air purification device in the air separation component thereby reducing the quantity of atmospheric air input to the air separation component.

32. The method of claim 42 including cooling the compressed gaseous emissions within the carbon dioxide capture component, subsequent to multistage compression and aftercooling by heat exchange to the liquefied captured carbon dioxide and the tail gas.

33. The method of claim 42 including: using the liquid nitrogen from the air separation component as the lower refrigerant in the carbon dioxide capture component; and using the liquid nitrogen from the air separation component as the lower refrigerant in the thermal energy conversion component to condense the vaporized upper refrigerant, thereby producing cooled nitrogen vapor.

34. The method of claim 33 including: using cooled nitrogen vapor from the captured carbon dioxide condenser and the upper refrigerant condenser as coolant for an aftercoolers for a booster compressor and for an aftercooler for a turbine air-booster compressor in the air separation component.

35. The method of claim 34 including: compressing the atmospheric air entering the air separation component: controlling the supply of compressed atmospheric air to a cryogenic air-separation unit of the air separation component, in which the oxygen and nitrogen are separated, by cooling a portion of the compressed atmospheric air that enters the cryogenic air-separation unit wherein cooling the portion of compressed atmospheric air is accomplished by the nitrogen vapor leaving the aftercoolers for the air-booster compressor and the aftercooler for the turbine air-booster compressor as warmed nitrogen vapor, after which the warmed is vented to the atmosphere.

36. The method of claim 35 including extracting a portion of the warmed nitrogen vapors vented to the atmosphere and directing the portion to the intake of a first stage of an atmospheric air compressor in the air separation component, thereby increasing liquid nitrogen production when the liquid nitrogen from the air separation component is inadequate to meet a combined demand from a captured carbon dioxide condenser and an upper refrigerant condenser.

37. The method of claim 2 42 including separately selecting discharge pressures from a plurality of turbo-expanders in the thermal energy conversion component to achieve a temperature of the repressured liquid upper refrigerant that avoids freezing in the aftercoolers.

38. The method of claim 37 including reheating the upper refrigerant exiting a first stage turbo-expander in the thermal energy conversion component by heat exchange in an aftercooler from the carbon dioxide capture component and from an aftercooler in the air separation component.

39. The method of claim 23 including: providing a portion of required by the air separation component from external sources and thereby reducing the output of oxygen and liquid nitrogen from the air separation component.

40. The method of claim 39 including increasing the supply of liquid nitrogen to meet demand when a portion of the oxygen required by the air separation component is supplied from external sources by a supplementary nitrogen liquefaction installation such that the total liquid nitrogen supply is adequate to meet the demand for the lower refrigerant.

41. The method in claim 24 including: combining condensed water produced in the carbon dioxide capture component and the air separation component as a single stream for disposal.

42. An integrated and interrelated three-component method for simultaneously capturing carbon dioxide emitted from combustion of fossil-energy fueled power generation in an oxyfuel mode, for supplying oxygen to support oxyfuel mode of combustion, and for collecting thermal energy liberated from carbon capture and oxygen supply for generating electricity, comprising: filtering, compressing, and cooling, in a carbon-dioxide capture component, gaseous emissions from the power generation installation in multistage compressors; intercooling between the multistage compressors with an upper refrigerant; separating the gaseous emissions into captured carbon dioxide, water, and tail gas; collecting low level thermal energy with the upper refrigerant for conversion to electricity; compressing atmospheric air and mixing with the tail gas to form a mixture of compressed atmospheric air and tail gas in an air separation component; separating gaseous oxygen from the mixture in the air separation component to support the oxyfuel combustion in the power generation installation; separating liquefied nitrogen from the mixture in the air separation component for use as a lower refrigerant in the carbon-dioxide capture component for liquefying the captured carbon-dioxide; reducing the pressure of the upper refrigerant in a thermal energy conversion component; converting low level thermal energy in the upper refrigerant to electricity by passing it through expander turbines, and represurizing the upper refrigerant with a pump.

43. A method for capturing carbon dioxide in gaseous emissions produced by OxyFuel mode combustion of fossil fuel in a power generating installation, comprising; directing the gaseous emissions from OxyFuel combustion in a power generating installation into a carbon-dioxide capture component; isolating and capturing the carbon dioxide content of gaseous emissions of the OxyFuel mode combustion power generation installation by multi-stage compression in a carbon-dioxide capture component and by intercooling between stages of the multi-stage compression with an upper refrigerant; aftercooling the carbon dioxide content of the gaseous emissions after a final stage of the multi-stage compression in a condenser in which heat of condensation is extracted by a lower refrigerant whereby the carbon dioxide content is condensed to a liquid carbon dioxide content; recovering water vapor content of the gaseous emissions as a liquid from during the intercooling between stages of the multi-stage compression and prior to after cooling; outputting a stream of the liquid carbon dioxide content, a stream of recovery water, and a stream of recycled gas from the carbon-dioxide capture component after isolating and capturing the carbon dioxide content of the gaseous emissions; directing the stream of recycled gas and a stream of atmospheric air into an air separation component for mixing into a mixture of recycled gas and atmospheric air; separating the mixture of recycled gas and atmospheric air within the air separation component into a stream of oxygen and a stream of nitrogen by multi-stage compression of the mixture of recycled gas and atmospheric air and intercooling between stages of the multi-stage compression with an upper refrigerant and aftercooling the mixture of recycled gas and atmospheric air after a final stage of the multi-stage compression; cooling the atmospheric air after multi-stage compression with a lower refrigerant of liquid nitrogen; directing the stream of oxygen being output from the air separation component into the power generating installation and venting the stream of nitrogen; producing electricity with a thermal energy conversion component from thermal energy generated by heat exchange into the upper refrigerant during the intercooling between stages of the multi-stage compression in the carbon-dioxide capture component and during the intercooling between stages of the multi-stage compression in the air separation component; reducing pressure of the upper refrigerant by turbo-expanders in the thermal energy conversion component that drive electricity generators; and condensing the upper refrigerant through heat exchange with the lower refrigerant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The structure, operation, and advantages of the present invention will become further apparent upon consideration of the following descriptions taken in conjunction with the accompanying eight figures (Figs.). The figures are intended to be illustrative, not limiting.

[0030] Certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. Cross-sectional views (if any) may be in the form of “slices”, or “near-sighted” cross-sectional views, omitting certain background pipe lines, which would otherwise be visible in a “true” cross-sectional view, for illustrative clarity.

[0031] In the drawings accompanying the description that follows, both reference numerals and legends (labels, text descriptions) may be used to identify elements. If legends are provided, they are intended merely as an aid to the reader, and should not in any way be interpreted as limiting.

[0032] FIG. 1 is a schematic view of a fossil-energy fueled, power generation Installation that includes three interrelated components, i.e., the Carbon-Dioxide Capture Component, the Air Separation Component, and the Thermal-Energy Conversion Component, according to the present invention.

[0033] FIG. 2 illustrates the processing functions for the Carbon Dioxide Capture Component of FIG. 1, according to the present invention.

[0034] FIG. 3 illustrates the processing functions for the Air Separation Component of FIG. 1, according to the present invention.

[0035] FIG. 4 illustrates the processing for the Upper Refrigerant in the Thermal Energy Conversion Component of FIG. 1, according to the present invention.

[0036] FIG. 5 illustrates the processing for the supply of the Lower Refrigerant and its utilization, according to the present invention.

[0037] FIG. 6 illustrates an alternative configuration to that shown in FIG. 2 with respect to the receipt of gaseous emissions from fossil-energy power generation, according to the present invention.

[0038] FIG. 7 illustrates the alternative configuration to that shown in FIG. 3, with respect to the receipt of atmospheric air, according to the present invention.

[0039] FIG. 8 shows the alternative configuration to that shown in FIG. 4, with respect to the inclusion of the two new Coolers 299 and 393, according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] In the description that follows, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by those skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. Well-known processing steps are generally not described in detail in order to avoid unnecessarily obfuscating the description of the present invention.

[0041] In the description that follows, exemplary dimensions may be presented for an illustrative embodiment of the invention. The dimensions should not be interpreted as limiting. They are included to provide a sense of proportion. Generally speaking, the relationship between various elements, where they are located, their contrasting compositions, and sometimes their relative sizes, is of significance.

[0042] In the drawings accompanying the description that follows, often both reference numerals and legends (labels, text descriptions) will be used to identify elements. If legends are provided, they are intended merely as an aid to the reader, and should not in any way be interpreted as limiting.

[0043] The structure, operation, and advantages of the present preferred embodiment of the invention will become further apparent upon consideration of the following description taken in conjunction with the accompanying drawings.

[0044] The present invention relates to a mode of combustion of fossil fuels, such as in a fossil-energy fueled power generation installation, in which the use of atmospheric air is eliminated. Instead, a portion of its gaseous emissions is recycled to the fuel burners, which has previously been mixed with essentially pure oxygen to the extent that can match the oxygen content of atmospheric air, commonly known as of OxyFuel Combustion. This mix thus substitutes for the conventional use of atmospheric air for combustion. As the result, the content of the chimney gases becomes largely carbon dioxide and water vapor. Only a small content of nitrogen and oxygen may exist along with trace quantities such as sulfur dioxide, mercury, and other toxic substances, depending on prior treatment of the gaseous emissions.

[0045] The technological means for carbon dioxide capture employed in the present invention is based on a cryogenic approach in which the capture of carbon dioxide occurs at temperatures sufficiently low and pressures sufficiently high such that, for example, the carbon dioxide liquefies through condensation from the gaseous emissions. The captured carbon dioxide liquid can then, if necessary, be pumped to the pressure required for pipe line transport to disposal other than into the atmosphere. This mode of carbon dioxide capture is enhanced by the minimization of the presence of nitrogen in the combustion system, especially by employing OxyFuel combustion.

[0046] Accordingly, a supply of essentially pure oxygen for the combustion of the fossil fuel in a fossil-energy fueled power generation installation is provided in accordance with the present invention by the incorporation of an Air Separation Component. Both the capture of carbon dioxide and the production of oxygen produce significant quantities of low temperature-level, by-product thermal energy because of intercooling and aftercooling during gas compression stages. The conversion of this by-product thermal energy to electricity is a unique feature of this invention.

[0047] Thus, the present invention may be perceived as comprising three interrelated components labeled the Carbon-Dioxide Capture Component, the Air Separation Component, and the Thermal-Energy Conversion Component, which serve a common purpose of the simultaneous capture of carbon dioxide, the provision of a supply of oxygen sufficient to support Oxyfuel combustion, and a minimized consumption of externally-supplied electricity. Each of these functions is accomplished in a separate processing component, within which either gaseous emissions for carbon dioxide capture or atmospheric air for air separation is compressed in multiple stages.

[0048] Intercooling between stages and aftercooling after the final compression stage liberate significant quantities of relatively low-temperature thermal energy and this low temperature-level thermal energy is captured and converted to electricity.

[0049] FIG. 1 is a schematic view of a fossil-energy fueled power generation installation 8, the three interrelated components of the present invention: the Carbon-Dioxide Capture Component 10, the Air Separation Component 12, and the Thermal-Energy Conversion Component 14. These three components are linked for the simultaneous capture of carbon dioxide and the provision of a supply of oxygen sufficient to support Oxyfuel combustion. The schematic view of FIG. 1 shows the receipt of a flow stream of gaseous emissions though pipeline 20 and of a flow stream of atmospheric air through pipe line 22, the output of a flow stream of captured carbon dioxide through pipe line 24, the supply of electricity through an electric line 26, the output of a flow stream of high-purity gaseous oxygen through pipe line 28, the venting of a flow stream of nitrogen through pipe line 30, and the directing of a flow stream of tail (recycle) gas through pipe line 32. It also shows these functions as being accomplished by the three interrelated processing components: the Carbon-Dioxide Capture Component 10, the Air Separation Component 12, and the Thermal-Energy Conversion Component 14.

[0050] The three processing Components 10, 12 and 14 are linked symbolically by the numbered flow streams represented by arrows indicating the direction of flow, as discussed herein below. Also shown is the recovery of water from the Carbon-Dioxide Capture Component 10, as discussed herein below. The recovery of water in the Carbon-Dioxide Capture Component 10 is directed through pipe line 34 to the Cooling Water Circuit 36 and mixed therein with the water makeup through pipe line 38 to provide a supply of water through pipe line 40 from the Cooling Water Circuit 36 to the processing equipment 42 in the Air Separation Component 12.

[0051] The gaseous emissions 20 are produced from Fossil-Energy Fueled Power Generation Installation 8 operating in an OxyFuel Combustion mode, in which the oxygen is supplied through pipe line 28 from the Air Separation Component 12. The Fossil-Energy Fueled Power Generation Installation 8 also supplies the net requirement of electricity through electric line 26, needed for the operation of the three interrelated processing components: the Carbon-Dioxide Capture Component 10, the Air Separation Component 12, and the Thermal-Energy Conversion Component 14 of the present invention.

[0052] The flow stream through pipe line 50 represents the supply of the Upper Refrigerant (in liquid form) from the Thermal-Energy Conversion Component 14 to the Air Separation Component 12 and its return as a vapor, after collecting low-level thermal energy for conversion to electricity. Similarly, the flow stream through pipe line 54 represents the supply of Upper Refrigerant (in liquid form) to the Carbon-Dioxide Capture Component 10 and its return as a vapor, after collecting low-level thermal energy for conversion to electricity. The flow stream through pipe line 56 represents the supply of the Lower Refrigerant as a liquid to the Thermal-Energy Conversion Component 14 for its use to condense the Upper Refrigerant and for its return as a vapor. The flow stream through pipe line 60 represents the supply of Lower Refrigerant to the Carbon Dioxide Capture Component 10 for its use in condensing captured carbon dioxide to a liquid and its return as a vapor.

[0053] The Switchyard 62 receives the electricity produced in the Thermal-Energy Conversion Component 14 stream through electric line 52 and the electricity through electric line 26 that is imported from the Fossil-Energy Fueled Power Generation Installation 8 to meet the total demand from an installation based on this invention. The switchyard 62 also distributes the combined quantities of electricity as required by the Air Separation Component 12 through electric line 66 and the Carbon Dioxide Capture Component through electric line 68. The Switchyard 62 also receives electricity that is generated by the expander in the Air Separation Component 12 through electric line 72.

[0054] The cooling-water circuit 36 is a conventional, cooling-tower based method for providing a stream of cooled water to the Processing Equipment 42 of the Air Separation Component 12 through pipe line 40 and receiving condensed water from the Carbon-Dioxide Capture Component 10 through pipe line 34. Makeup water is directed into the cooling-water circuit 36 through pipe line 38 to replace the evaporated water which is removed 74 from the cooling-water circuit to the atmosphere. The quantity of makeup water is reduced by the stream of condensate delivered to the cooling-water circuit 36 through pipe line 34 from the Carbon-Dioxide Capture Component 10 and internally in the Air Separation Component 12 from the stream of water condensed from the atmospheric air.

[0055] The functions and relationships illustrated in FIG. 1 are further clarified in FIGS. 2, 3, 4, and 5.

[0056] FIG. 2 illustrates the processing functions for the Carbon-Dioxide Capture Component 210 (compares to 10 in FIG. 1). A fossil-energy fueled power generating installation employing OxyFuel combustion 208 may comprise a single or multiple power-generating units, which singly, or together, supply all or part of the gaseous emissions through pipe line 209, from which the carbon dioxide content is to be captured. A stream of oxygen for combustion in the Fossil-Energy Fueled Power Generating Installation 8 is supplied from the Air Separation Component 12 (see FIG. 1) though pipe line 211 (corresponding to pipe line 28 in FIG. 1).

[0057] The stream of gaseous emissions flowing through pipe line 209 is first cleaned of particulate matter in the gas filter 213 and then moved through pipe line 215 to be compressed in the first-stage compressor 217. The stream of compressed gases is delivered through pipe line 219 from the first-stage compressor 217 to the cooler 221. The cooling medium 223 which flows through cooler 221 is the evaporation of the liquefied Upper Refrigerant. The stream of cooled compressed gases exiting cooler 221 flows through pipe line 225 and is then directed into separator 227, in which condensed water is separated and ejected through pipe line 229. A stream of the partially-dried gases from the separator 227 is directed through pipe line 231 into compressor 233. The further-compressed gases exit compressor 233 and are directed through pipe line 235 into cooler 237. The cooling medium 238, which flows through cooler 237, is the liquefied Upper Refrigerant. The cooled gases exiting cooler 237 are directed through pipe line 239 to separator 243 for the further removal of water condensate through pipe line 245.

[0058] The stream of residual gases are directed out of the separator 243 through pipe line 247 and delivered to third-stage compressor 249. The further-compressed gases exiting the third-stage compressor 247 through pipe line 251 are delivered to cooler 253 where they are cooled and delivered through pipe line 255 to separator 257, in which the condensed water is separated and removed through pipe line 258. The cooling medium 259, which flows through cooler 253, is liquefied Upper Refrigerant. The stream of residual gases is directed out of separator 257 and through pipe line 261 into dryer 263. After being processed in the dryer 263 for the complete removal of moisture, the stream is directed as residual moisture through pipe line 265.

[0059] The stream of completely-dried and finally compressed gases exiting dryer 263 through pipe line 267 is separated into two streams, one flowing through pipe line 269 and the other through pipe line 271. These two streams are separately, in parallel, fed to coolers 273 and 275. The stream of gases from pipe line 269 is cooled in cooler 273 by heat exchange with non-condensable (tail) gases flowing through pipe line 277 from the Flash Drum 279 in which liquefied carbon dioxide has been separated.

[0060] The stream of completely-dried and finally compressed gases flowing through pipe line 271 is cooled in cooler 275 by heat exchange with the stream of liquefied carbon dioxide flowing through pipe line 281 from Pump 282. The pressure of the liquefied carbon dioxide flowing in pipe line 297 from the Flash Drum 279 is increased by pump 282 to pipe line requirement. The heated carbon dioxide from cooler 275 is exported as a stream through pipe line 298 for utilization or sequestration. The heated tail gases exiting cooler 273 through pipe line 283 are further processed as described below.

[0061] The cooled gases exiting coolers 273 and 275, through pipe lines 284 and 285, respectively, are combined into a single stream flowing through pipe line 286. The stream of gases exiting pipe line 286 enters condenser 287 where they are cooled to condensing temperatures for the carbon dioxide content therein. The condensing medium flowing into pipe line 295 and in pipe line 296 is the Lower Refrigerant. The condenser effluent flows through pipe line 289 into the flash drum 279 for the separation of the liquefied carbon dioxide as a stream flowing into pipe line 297 and the non-condensable stream of gases, i.e., the tail gas, flows through pipe line 277.

[0062] The stream of separated tail gases flowing through pipe line 283 is reduced in pressure by an expansion valve 290 and fed immediately into conventional equipment 291 in which essentially all of the carbon dioxide content is converted to a solid carbon dioxide “snow” exiting through pipe line 292. The tail gases, now containing only traces of carbon dioxide, are sent through pipe line 293 (compare pipe line 32 in FIG. 1) to the Air Separation Component 12 as shown in FIG. 1.

[0063] FIG. 3 illustrates the processing for the Air Separation Component 300 (Compare 12 in FIG. 1). The cryogenic air-separation unit 302 (also identified as Cold Box) and the compressed-air purification unit 304 are conventional. However, the means for supplying purified compressed air for the cryogenic air-separation unit 302 are unique to this invention as will become evident from the description that follows.

[0064] Dust and other particulate matter in the atmospheric-air stream input flowing in pipe line 306 are removed by an air filter 308. The resulting stream of cleaned air is delivered through pipe line 310 to mixer 312. The mixer 312 also receives a stream of recycled nitrogen vapor through pipe line 314 on occasions when such recycle is required. The cleaned air and recycled nitrogen vapor are directed through pipe line 316 from the mixer 312 to a first-stage compressor 318.

[0065] The stream of compressed air exiting first-stage compressor 318 is directed through pipe line 320 to cooler 322. The cooling medium for the stream of compressed air flowing through the cooler 322 is the evaporation of the Upper Refrigerant 324 (Compare 438 in FIG. 4). The stream flowing through pipe line 326 is then separated with condensed water stream flowing into pipe line 328 while the other partially-dried stream flows through pipe line 330 into compressor 332.

[0066] The further-compressed stream exits compressor 332 into pipe line 334 where it is divided into two streams, one flowing through pipe line 336 into cooler 340 and the other one flowing through pipe line 338 into cooler 342. The cooling medium 344 for cooler 340 is the reheat of the Upper Refrigerant as shown in FIG. 4. The cooling medium 345 for cooler 342 is cooling water from the cooling water circuit 36 flowing into pipe line 40 as shown in FIG. 1. The cooled streams exiting coolers 340 and 342 through pipe lines 346 and 348, respectively, are joined in mixer 350 and exit as a single stream into a pipe line 352. However, before reaching the mixer 350, a stream of condensed water is separated into pipe line 354 and joined with the stream from pipe line 328 as a stream of condensate in pipe line 354. The stream of cooled compressed atmospheric air flowing through pipe line 352 is joined with the tail gas stream flowing through pipe line 358 (corresponding to pipe line 293 in FIG. 2) in mixer 359 and exits the mixer through pipe line 360.

[0067] The stream of compressed air flowing through pipe line 360 is delivered to compressed-air purification unit 304, in which traces of moisture and carbon dioxide are removed. The resulting stream of purified compressed air exits the Compressed Air Purification unit 304 through a pipe line 361 and is divided into two streams, one flowing into pipe line 364 and the other flowing into pipe line 366. The stream flowing through pipe line 364 is fed into cooler 368. The other stream flowing through pipe line 366 is divided into two streams, one of which flows into pipe line 370 which is directed to compressor 372 and the other into pipe line 374 which is directed into Turbo Air-Booster Compressor 376, which is integral with the Cold Box 302.

[0068] The stream flowing through pipe line 364 is fed into a cooler 368 and exits as a cooled stream into pipe line 378, which enters the Cold Box 302. The cooling medium flowing into cooler 368 through pipe line 380 is nitrogen vapor as shown in FIG. 5 as stream 510. The stream of heated nitrogen vapor exits cooler 368 through pipe line 381 and is then split into two streams 383 and 314. The stream of nitrogen 314 is withdrawn as recycle on occasions when recycling is required and fed for mixing with the stream flowing through pipe line 310 into the Mixer 312. The stream of nitrogen flowing through pipe line 383 is vented to the atmosphere.

[0069] The compressed air stream from compressor 372 is directed through pipe line 384, cooled in cooler 385, and then fed through pipe line 386 to the Cold Box 302. The cooling medium 387 for cooler 385 is the Lower Refrigerant as shown in FIG. 5.

[0070] The compressed air stream flowing through pipeline 388 from the Booster Compressor 376 is cooled in cooler 389 and fed through pipe line 390 into the Cold Box 302. The cooling medium 391 for the cooler 389 is the Lower Refrigerant as shown in FIG. 5.

[0071] Conventional processing within the Cold Box 302 separates the compressed air streams through pipe lines 378, 386, and 390 into a stream of high-purity oxygen vapor and as a stream of high-purity nitrogen liquid which may contain argon. The stream of high-purity oxygen vapor is delivered into pipe line 391 at near ambient temperature and pressure. The stream of high-purity nitrogen liquid, which may contain argon, at near ambient pressure is delivered into pipe line 392. The argon content of atmospheric air is delivered as part of the liquid nitrogen product or, optionally, can be delivered from the Cold Box 302 as a separated product.

[0072] FIG. 4 illustrates the processing for the Upper Refrigerant in the Thermal-Energy Conversion Component 400 (Compare 14 in FIG. 1). The process begins with a stream of the Upper Refrigerant, which exits pump 404 as a liquid at elevated pressure being directed into pipe line 402. The liquid Upper Refrigerant is at a minimized temperature that avoids freezing of the moisture in the gaseous emissions being cooled in Coolers 406, 408, 410, and the atmospheric air being cooled in Cooler 412. The liquid stream of the Upper Refrigerant flowing through pipe line 402 divides into four streams flowing through pipe lines 414, 416, 418 and 420. The streams flowing through pipe lines 414, 416, 418 and 420 enter coolers 406, 408, 410, and 412, respectively, and exit the coolers through pipe lines 422, 424, 426 and 428, respectively.

[0073] The effluents from the coolers 406, 408, 410, and 412, now vaporized, are combined at elevated pressure and flow through pipe line 430. The vaporization occurs because of the thermal energy received from the media cooled in the four coolers. For coolers 406, 408, and 410, the media 432, 434 and 436, respectively, are the cooling of the gaseous emissions from pipe lines 219, 235, and 251 in FIG. 2. For cooler 412, the medium 438 is the cooling of the compressed air stream in pipe line 320 in FIG. 3.

[0074] The pressure in the stream through pipe line 430 is reduced in expander 439 and then flows through pipe line 440 into cooler 442 where it is reheated by the cooling of compressed air (the stream through pipe line 336 in FIG. 3). The reheated stream exiting the cooler 442 is directed through pipe line 444 into expander 446 in which the pressure is reduced to a level selected to enable the temperature level required for the stream flowing through pipe line 402. The two expanders 439 and 446 are represented in FIG. 1, illustratively, as expander 80.

[0075] The stream of effluent flowing from pipe line 448 from expander 446 is fed into condenser 450, which accommodates recirculation of the streams through pipe lines 452 and 454 of uncondensed Upper Refrigerant by Booster Compressor 456. The condensing medium is the Lower Refrigerant (the stream through line 517 in FIG. 5). The stream of condensed Upper Refrigerant is fed to Flash Drum 458 through pipe line 460. The stream of liquid exiting the Flash drum 458 through pipe line 462 is increased in pressure to the required level by pump 404.

[0076] FIG. 5 shows the processing for the supply of the Lower Refrigerant and its utilization. Illustratively, liquid nitrogen is selected as the Lower Refrigerant, its source being the Air-Separation Sub-Component 500 (compare 300, stream 392, in FIG. 3). The pressure of the stream of liquid nitrogen in pipe line 502 received at near ambient pressure is increased by pump 504 and directed as a stream into pipe line 506. The stream flowing through pipe line 506 is divided into streams 508 and 510. The division is determined by the consumption of the Lower Refrigerant in the condensers 512 and 514, with the excess becoming the stream flowing through pipe line 508.

[0077] The stream flowing through pipe line 510 further divides into streams flowing through pipe lines 516 and 518. The stream through pipe line 516 serves the condenser 512 for condensing the Upper Refrigerant (the condenser 450 in FIG. 4) and the stream through pipe line 518 serves the condenser 514 for condensing the captured carbon dioxide (the condenser 287 in FIG. 2). The condensing conditions in each case are set to avoid freezing of either the Upper Refrigerant or of the captured carbon dioxide. The means to avoid freezing, illustratively, is recirculation of a portion of the condensing medium through booster compressors 520 and 522.

[0078] For condenser 512, the temperature of the stream being inputted through line 517 is adjusted by the amount of recirculation of the stream through pipe line 524 and the amount of Lower Refrigerant flowing as a stream through pipe line 516. The effluent stream from Condenser 512 supplies the recirculation stream through pipe line 526. The remainder of the effluent stream from Condenser 512, which is stream 538, becomes equal to the flow rate for the stream through pipe line 516. Similarly for condenser 514, the temperature of the stream flowing though pipe line 529 is adjusted by the amount of recirculation of the stream flowing into pipe line 530 and the amount of the Lower Refrigerant flowing through pipe line 528. The effluent stream through pipe line 532 supplies the recirculation stream flowing through pipe line 534. The remainder flowing through pipeline 536 becomes equal to the flow rate for the stream flowing through pipe line 528.

[0079] The combined stream through pipe lines 538 and 536 flow into pipeline 540 as the demand for liquid Lower refrigerant requires, with surplus liquid Lower Refrigerant flowing through pipe line 508 into mixer 542 and exiting into pipe line 544.

[0080] The stream flowing through pipe line 544 divides into two streams flowing through pipe line 546 and pipe line 548. The stream flowing through pipe line 548 represents the quantity of Lower Refrigerant not required for the cooling functions in coolers 550 and 552. The stream flowing through pipe line 546 divides into two streams. The first of the streams flows through pipe line 554 and the second of the streams through pipe line 556. The stream from pipe line 554 exits cooler 552 (cooler 385 in FIG. 3) as a stream through pipe line 557, in which cooler 552 a portion of the purified compressed air in the Air Separation Component (the stream through pipe line 384 in FIG. 3), is cooled. The stream flowing through pipe line 556 exits cooler 550 (Cooler 389 in FIG. 3) as a stream through pipe line 558, in which cooler a portion of the purified compressed air in the Air Separation Component 12 (the stream through pipeline 388 in FIG. 3) is cooled.

[0081] The two streams through pipe lines 557 and 558 are combined in mixer 560 and exit the mixer as a stream flowing through pipe line 562. The stream through pipe line 562 is combined with the surplus stream flowing through pipe line 548 in mixer 564 and exits the mixer as a stream flowing through pipe line 566. The pressure in the stream through line 566 is reduced to near ambient in expander 568. The effluent stream exits the expander 568 through pipe line 510, which becomes the stream flowing through pipe line 380 in FIG. 3.

Other Embodiments

[0082] The foregoing descriptions of the features of the preferred embodiments have focused on an installation based on the embodiments (or configurations) illustrated in FIGS. 1 through 5 above. Nevertheless, it should be fully understood that an installation covered by this invention can be configured in alternative ways that meet the same objectives as discussed in the technical field of the Invention above. Some examples of alternative configurations, as other embodiments, are illustrative and follow.

[0083] Any configuration for this invention offers opportunities for modifying pressures and temperatures for the operating equipment that are embodied in a configuration. A primary objective for modifying pressures and temperatures is to achieve a reduction in the amount of externally supplied electricity required for the invention to operate (the stream through electric line 26 in FIG. 1).

[0084] The configuration in FIG. 1 is based on the supply of electricity from external sources (the stream through electric line 26). In this configuration all drivers for the compressors in FIGS. 2, 3, and 5 are electrical. Alternatively, some or all of these compressors can be driven by expansion turbines that employ high-pressure steam, either in a topping mode in which steam at a reduced pressure is returned to the source, or in a condensing mode in which condensed steam (i.e., feed water) is returned to the source.

[0085] In FIG. 2, processing of the Tail Gas (the stream through pipe line 293 in FIG. 2) can be eliminated and the tail gas vented to the atmosphere, thereby marginally reducing the amount of carbon dioxide capture. Also in FIG. 2, the liquefied carbon dioxide forming the stream through pipeline 297 is shown to be compressed to pressure suited to pipe line transport by pump 282. Alternatively, conventional processing may be introduced whereby any portion of the carbon dioxide that is captured as a high-pressure liquid flowing through pipe line 297 is detoured for conversion to a solid product (dry ice), or as lower pressure feedstock suited for chemical production feedstock, or for algae cultivation, as examples.

[0086] In FIG. 2 the number of stages of compression shown to produce the stream flowing through pipeline 267 is illustrative. The number may be larger or smaller with the number of intercoolers adjusted to suit. Moreover and alternatively, initial cooling and major condensation of the water vapor content in the gaseous emissions may be accomplished by introducing an additional cooler and separator within stream 209 or stream 215, with the use of the Upper Refrigerant as the cooling medium. Thus, the flow rate and the temperature of the gaseous emissions fed to the first-stage compressor 217 are reduced as well as its power consumption. This embodiment adds an additional cooling load to be accommodated in the downstream processing of stream 430 in FIG. 4.

[0087] In FIG. 2, the cryogenic capture of carbon dioxide as a liquid at high pressure may alternatively be replaced by the use of a process involving specialized inorganic or organic chemical agents. For example, ammonium carbonate/bicarbonate and organic amine solutions have properties of selectively absorbing carbon dioxide from a mixture of gases at one set of pressure and temperature and liberating (desorbing) the absorbed carbon dioxide at another set of pressure and temperature. The carbon dioxide thus captured may then be compressed and cooled at a pressure suited to pipe line transport with associated low-level thermal energy captured and converted to electricity as described above.

[0088] In FIG. 2 the solid carbon dioxide “snow” may be further processed either, or both, by compression to solid blocks of dimensions suited to marketing conditions or as a liquid under elevated pressure suited to blending with the main liquid carbon dioxide stream. Stream 292 in FIG. 2 can produce carbon dioxide “snow”, compressed carbon dioxide blocks, and liquid carbon dioxide. In the case of liquid carbon dioxide, Line 292 in FIG. 2 would be extended and connected to Line (Stream) 297 at the inlet of Pump No. 3.

[0089] In FIG. 3, the cooling medium for cooler 322 may be water from the cooling water circuit 36 in FIG. 1 instead of the Upper Refrigerant. Also in FIG. 3, the cooling medium for cooler 340 may be water from the cooling water circuit. The cooling medium for the coolers 385 and 389 may be the Upper Refrigerant instead of the Lower Refrigerant. Cooler 368 may be eliminated and the cooling medium flowing through line 380 vented directly to the atmosphere.

[0090] In FIG. 3, the stream of liquid nitrogen flowing through line 392 is produced as refrigerant for Condensers 512 and 514 in FIG. 5. Occasions may arise, such as instances where a portion of the oxygen required for the OxyFuel mode (the stream flowing through line 28 in FIG. 1) is supplied from external sources, where consequently the quantity of liquid nitrogen produced for the stream flowing through line 392 in FIG. 3) is less than what is required for Condensers 512 and 514 in FIG. 5. In such cases, a portion of the nitrogen vapor (the stream through pipeline 314 in FIG. 3 may be directed for mixing with the atmospheric air input (the stream flowing through pipeline 310 in FIG. 3), thereby establishing a recirculation stream to produce the required liquid nitrogen output through the pipeline 392 in FIG. 3.

[0091] Moreover and alternatively, initial cooling of atmospheric air and condensation of its content of water vapor may be accomplished by introducing an additional cooler and separator within stream 306 or stream 310, with the use of the Upper Refrigerant as the cooling medium. Thus, the temperature of the atmospheric air and its moisture content fed to the first-stage compressor 318 are reduced, as well as its power consumption. The alternative adds an additional cooling load to be accommodated in the downstream processing of stream 430 in FIG. 4.

[0092] In FIG. 4 the thermal energy transferred in cooler 442 is used to reheat the partially expanded Upper Refrigerant vapors flowing through pipeline 440 from the Expander 439. This function can also be accomplished, alternatively, through substitution of cooler 442 by another cooler.

[0093] In FIG. 4, the number of turbo-expansion stages is illustrative. For example, three stages of expansion can be configured, in which the reheating function in cooler 442, for example, is complemented by an additional expander and an intercooler from the available roster of coolers.

[0094] In FIG. 5, the discharge pressure from Pump 504 can be selected such that excess liquid Lower Refrigerant flowing through pipeline 508 is minimized, if not eliminated. In addition, as described above, the cooling function in coolers 550 and 552 can be accomplished with the Upper Refrigerant instead of the Lower Refrigerant.

[0095] In FIG. 5, the stream flowing through pipeline 508 represents an excess of the Lower Refrigerant that is by-passed to mixer 542. Such by-passing is thermally inefficient. If an external supply of oxygen is available, the capacity of the Air Separation Component (12 in FIG. 1) can be reduced such that the quantity of by-pass of the Lower Refrigerant is minimized. At the same time the quantity of external electricity flowing through electric line 26 in FIG. 1 is reduced.

[0096] FIGS. 6, 7, and 8 describe alternative configurations to those illustrated by FIGS. 2, 3, and 4. These alternatives in principle acts to reduce the temperature of the gaseous emissions entering the Carbon-Dioxide Capture Component and the temperature of the atmospheric air entering the Air Separation Component. The means for accomplishing the reductions in temperature is the Upper Refrigerant. In the descriptions of FIGS. 6, 7, and 8, the numbering of streams and equipment is unchanged, except for new numbering of streams and equipment that are introduced.

[0097] FIG. 6 illustrates the alternative configuration to that shown in FIG. 2 with respect to the receipt of gaseous emissions from fossil-energy power generation. Stream 209 connects the gaseous emissions from a fossil-energy fueled power generating installation to a new Cooler 299, in which the reduction in temperature of Stream 209 occurs. The cooling medium 210 is the Upper Refrigerant. Stream 209 exiting from Cooler 299 as stream 218 connects with Separator 214 in which the water that has been condensed from stream 209, because of the reduction in temperature in Cooler 299, is separated and removed as stream 216. The residual vapor flowing from the Separator 214 as stream 212 enters the Air Filter 213 as stream 212 for the removal of any residual particulates. Flow stream 215 leaving the Air Filter 213 connects with Compressor No. 1 as in FIG. 2. Flow stream and equipment configurations subsequent to Compressor No. 1 (217 in FIG. 2) are identical with those shown in FIG. 2.

[0098] FIG. 7 illustrates an alternative configuration to that shown in FIG. 3, with respect to the receipt of atmospheric air. Stream 306 connects the atmospheric air input to a new Cooler 393, in which the reduction of temperature of stream 306 occurs. The cooling medium 394 flowing through cooler 393 is the Upper Refrigerant. Stream 395 exiting from Cooler 393 is directed into the Air Filter 308. Flow stream 310 leaving the Air Filter 308 is directed into Mixer 3 (312) as shown in FIG. 3. Mixer 3 (312) also receives the nitrogen recycle stream 314. Flow stream and equipment configurations subsequent to flow stream 316 from Mixer 3 (312) are identical with those shown in FIG. 3.

[0099] FIG. 8 shows an alternative configuration to that shown in FIG. 4, with an inclusion of two additional Coolers 471 and 472 illustrated as being disposed below Cooler 11 in FIG. 4. The inlet and outlet headers now serve the additional Coolers 471 (210 in FIGS. 6) and 472 (393 in FIG. 7). Stream 465 is the flow stream 209 in FIG. 2. Stream 467 is the flow stream 306 in FIG. 3. Cooler 10 (471) receives high-pressure Upper Refrigerant liquid as stream 470 and discharges high-pressure Upper Refrigerant vapor as stream 464. Cooler 11 (472) receives high-pressure Upper Refrigerant liquid as stream 468 and discharges high-pressure Upper Refrigerant vapor as stream 466. High-pressure, liquid Upper Refrigerant feed to the Inlet Header and receipt of high-pressure, vapor Upper Refrigerant from the Outlet Header are identical as shown in FIG. 4. Processing of the flow stream from the Outlet Header through to the supply of Upper Refrigerant to the Inlet Header is identical as shown in FIG. 4.

[0100] In the description of this above, the basis has been the supply of the oxygen requirement in the OxyFuel mode of combustion entirely by means of an air separation component. However, it is possible that an external supply of oxygen is conveniently available, which can reduce, if not eliminate the need for air separation to provide the oxygen supply. An example of this possibility is the presence of an installation adjacent to an installation based on this invention in which algae is cultivated through the process of photosynthesis in which oxygen is a by-product. Another example is the possible presence of a nearby air separation installation supplying oxygen to another market, which is not large enough to absorb the available oxygen supply, the surplus then becoming available for supply to an installation based on this invention.

[0101] If no external supply of oxygen is available, the likelihood is that the nitrogen quantity separated in the Air Separation Component will be adequate, if not more than adequate, to supply the required quantity of the Lower Refrigerant. If this is not so, or if an external supply of oxygen is available, some of the vented oxygen (Stream 314 in FIG. 3) can be by-passed for addition to the atmospheric air (Stream 310 in FIG. 3) to increase the output of Lower Refrigerant from the Air Separation Component of this invention.

[0102] However, it is possible that a more technologically attractive alternative is available to assure an adequate supply of Lower Refrigerant. Instead of the Stream 314 (FIG. 3) being destined for mixing with atmospheric air, this stream can be subjected as feedstock to a conventional nitrogen liquefaction installation, separated from air separation in the air separation component.

[0103] Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, certain equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described components (assemblies, devices, etc.) the terms (including a reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure, which performs the function in the herein illustrated exemplary embodiments of the invention. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more features of the other embodiments as may be desired and advantageous for any given or particular application.