Waste heat recovery integration with carbon capture and optional compression

Abstract

A method of capturing carbon from a heated flow (204) utilizing waste heat recovery with a carbon capture process (200) comprises the steps of: diverting the heated flow from a waste heat source (202)

Description

BACKGROUND

[0001] The Carbon Capture and Storage (CCS) process is a very energy intensive process consuming energy in both electrical as well as thermal form. The thermal energy is required for regeneration of amine or any other sorbent where CO2 is separated from sorbent-CO2 bond. The generation of the necessary energy creates additional CO2 emissions if the energy supplied is from fossil fuel-based processes, which has the negative effect of reducing the net amount of carbon captured in a CCS process or plant.

[0002] US2013 / 0229012AI discloses a post combustion carbon capture plant adapted for use with waste heat from a flue gas from a boiler of a power plant (electricity generation) located upstream from the carbon capture plant. The flue gas contains ash and requires the removal of ash via an electrostatic precipitator prior to entering the waste heat recovery unit of the carbon capture plant downstream of the power plant. The electricity required by the carbon capture plant is provided by the power plant and the waste heat recovery unit generates supplemental heat that is used for the regeneration process of the carbon capture plant. The carbon capture unit requires external energy (electrical or thermal) for operation, such as electricity from the power plant.

[0003] Most of CCS plants are currently under development or are being implemented in industries that produce a substantial amount of CO2 as part of the core process as well as secondary processes, such as heating and production of steam. Reduction of CO2 production is hard-to-abate in these types of industries or industrial processes because they inherently consume massive amounts of energy, with a significant portion of it being wasted or unrecoverable. Instead of wasting the heat produced by the heat sources (which consumes additional energy and water) of these industrial processes, the waste heat can be recovered to generate power in a waste heat recovery plant. Using heat recovery to generate the electricity or heat can be additionally used in a CCS process has the benefit of reducing the overall energy consumption for the CCS process, and consequently decreasing CO2 emissions produced by the CCS process which increases the net amount of CO2 captured by the CCS process.

[0004] The CCS process can require additional auxiliaries or secondary processes that also require electrical or mechanical energy and produce waste heat. One example is a compressor, which are generally a centrifugal, rotary, scroll, reciprocating or turbo compressor that is spun by an electric motor or turbine (or any known method of compression). Regardless of the method of compression used, the compressor used to compress CO2 or other fluid in a CCS process will generate a significant amount of heat which will require a dedicated cooling system to maintain the compressor’s operating efficiency. This energy can also be recovered using a heat pump to supply heat to the various operations of the CCS plant.

[0005] In conventional CCS plants, electricity is provided from captive power plants (CPP) or from the electrical grid. The heat required in the regeneration process of the sorbent (also known as the desorption process) is either supplied from a dedicated (fossil fuel-fired) boiler or via an electrical heater. In some concepts it has been envisaged to supply the process waste heat to reboilers using a HEX (heat exchanger) to supplement the boiler or reboiler used in the desorption process, see FIG. 1.

[0006] The present or conventional waste heat recovery (WHR) configurations currently in use or contemplated implement the WHR unit upstream of the CCS process, see FIG. 1. The WHR unit recovers the waste heat from an independent operation and converts up to 25% of the waste heat energy by generation of electricity and the rest of the waste heat energy is released to the atmosphere in condensers (air or water cooled). One disadvantage of this WHR configuration is that the amount of available waste heat energy is entirely dependent on the independent operation that generates the waste heat energy. Examples of the independent operations include steel mills, foundries, and cement plants. The operational schedule and the amount of waste heat energy can vary depending on operating capacity or seasonal demand. When waste heat is not available or not sufficient to operate the CCS process conventional heaters or boilers are needed to replace or compensate for the lack of waste heat or insufficient waste heat for independent operation. Depending on the amount of waste heat available, a CCS process can be required to operate a heater or boiler, which require power from a combined heat and power (CHP) plant or directly consume a fossil fuel.

[0007] In these CCS configurations that compress the CO2 that is captured, the heat generated during the compression of the CO2 or compression heat is rejected or transferred to a cooling water flow in the intercoolers or other type of heat exchanger. The rejected heat is released to the atmosphere via heat transfer in cooling towers, air fin coolers, etc. These water-based cooling methods also have the disadvantage of requiring and consuming a significant amount of water, for example evaporative water cooling as water is released to the atmosphere. In some prior art applications, it has been proposed to utilize the flue gas waste heat for the sorbent regeneration process. In some cases, the steam from a (fossil fuel or waste fuel fired) CHP plant is provided to the CCS process. However, in these concepts the above-mentioned disadvantages are still present, particularly the availability and maximum recovery of the waste heat.

[0008] The present invention proposes a configuration and method of integrating external process supplied WHR (based on Steam Rankine Cycle or Organic Rankine Cycle or supercritical carbon dioxide (sCO2) Cycle or any other thermodynamic cycle), compression and any other source of heat recovery (with or without heat pump) with CCS projects and allows for the minimization of the loss of heat energy to the atmosphere via condensers, cooling towers or other HEX. The electricity generated from the WHR solution can power the CCS equipment with no additional CO2 emissions generated by external sources, rather without having a negative impact on the net amount of CO2 captured by the CCS process. The heat rejection from the thermodynamic cycle is carried out in HEX providing the necessary heat for the desorption cycle of the sorbent without generating any additional CO2 emissions. With this integrated solution approach, no dedicated (fossil fuel-fired) boiler is required thereby reducing the CAPEX as well OPEX. This will enhance the efficiency of WHR solution to highest possible efficiency, lower the overall water consumption, lower the CO2 emissions, and maximize the net CO2 captured from CCS project. BRIEF SUMMARY

[0009] The present invention overcomes the disadvantages discussed above by using a WHR solution to generate the electricity and thermal energy required for a CCS process without the need for a separate fired boiler / heater, increasing the amount of net CO2 captured by a CCS process, reduced CAPEX and OPEX, increased WHR and compressor efficiency and reduce water consumption.

[0010] In an embodiment the present disadvantages are overcome by a method of capturing carbon from a heated flow utilizing waste heat recovery with a carbon capture process includes the steps diverting the heated flow from a waste heat source and circulating the heated exhaust flow through a waste heat recovery unit to produce a cooled exhaust flow, pumping a first water flow from a combined water flow via a pump into the waste heat recovery unit and generating a first steam flow at first steam temperature and a first steam pressure, flowing the first steam flow into a steam turbine to create a second steam flow with a second steam temperature and a second steam pressure, rotating the steam turbine and an electrical generator with the first steam flow to produce an amount of electrical energy, powering the carbon capture process with a portion of the electrical energy produced by the electrical generator, circulating an amount of the cooled exhaust flow to an absorption unit and absorbing CO2 from the cooled exhaust flow via a lean sorbent to produce a CO2 lean exhaust flow, flowing the second steam flow to a sorbent heat exchanger of a desorption unit to heat a rich sorbent, condensing the second steam flow into a second water flow, flowing an outlet flow at an outlet temperature and an outlet pressure from the steam turbine to the water reservoir, combining the second water flow with an output of the water reservoir to create the combined water flow, flowing the combined water flow into the pump, extracting CO2from the rich sorbent during a sorbent regeneration process to create a flow of CO2, releasing the CO2 lean exhaust flow to the atmosphere as vented exhaust.

[0011] In one embodiment, the method further includes, flowing a portion of the combined water flow into the pump and diverting the remainder to a heat pump as a high temperature end cooling water flow, compressing the flow of CO2 in a compressor to create an amount of compressed CO2 and an amount of compression heat, cooling the compressor with the low temperature cooling water flow, re-boiling the high temperature end cooling water flow by transferring the compression heat to the high temperature end cooling water flow via a heat pump and returning the high temperature end cooling water flow to the second steam temperature and second steam pressure, supplementing the second steam flow with an output of the heat pump.

[0012] In one embodiment, the method further includes, circulating an amount of the cooled exhaust flow back to the waste heat source for a reuse and circulating the remainder to an absorption unit and absorbing CO2 from the cooled exhaust flow via a lean sorbent to produce a CO2 lean exhaust flow.

[0013] In one embodiment, the method further includes, replacing the water reservoir with a condenser and condensing the combined water flow prior to entering the pump.

[0014] In one embodiment, the method further includes, supplying the grid or an industrial process with an amount of electricity produced by the generator.

[0015] In one embodiment, the method further includes, replacing the cooled exhaust flow with a CO2 containing gas and circulating the CO2 containing gas to the absorption unit and absorbing CO2 from the CO2 containing gas via a lean sorbent to produce a CO2 lean gas flow, venting the post absorption gas to the atmosphere.

[0016] In one embodiment, the present disadvantages are overcome by a method of capturing carbon from a heated flow utilizing waste heat recovery with a carbon capture process includes the steps diverting the heated flow from a waste heat source and circulating the heated flow through a waste heat recovery unit to produce a cooled exhaust flow, pumping a first water flow from a combined water flow via a pump into the waste heat recovery unit and generating a first steam flow at first steam temperature and a first steam pressure, flowing the first steam flow into a steam turbine to create an outlet flow with a second steam temperature and a second steam pressure, rotating the steam turbine and an electrical generator with the first steam flow to produce an amount of electrical energy, powering the carbon capture process with a portion of the electrical energy produced by the electrical generator, circulating an amount of the cooled exhaust flow to an absorption unit and absorbing CO2 from the cooled exhaust flow via a lean sorbent to produce a CO2 lean exhaust flow, flowing the outlet flow to a sorbent heat exchanger of a desorption unit to heat a rich sorbent, condensing the outlet flow into a second water flow, flowing the second water flow to a water reservoir, combining the second water flow with the contents of the water reservoir to create the combined water flow, flowing the combined water flow into the pump, extracting CO2 from the rich sorbent during a sorbent regeneration process to create a flow of CO2, releasing the CO2 lean exhaust flow to the atmosphere as vented exhaust.

[0017] In one embodiment, the present disadvantages are overcome by a method of capturing carbon from a heated exhaust flow utilizing waste heat recovery with a carbon capture process includes the steps diverting the heated flow from a waste heat source and circulating the heated flow through a waste heat recovery unit to produce a cooled exhaust flow, circulating a thermic fluid between the waste heat recovery unit and a heat exchanger, pumping a first fluid flow from a thermic fluid reservoir via a feed pump into the heat exchanger and generating a first vapor flow at a first vapor temperature and a first vapor pressure, flowing the first vapor flow into a turbine to create a second vapor flow with a second vapor temperature and a second vapor pressure, rotating the turbine and an electrical generator with the first vapor flow to produce an amount of electrical energy, powering the carbon capture process with a portion of the electrical energy produced by the electrical generator, circulating an amount of the cooled exhaust flow to an absorption unit and absorbing CO2 from the cooled exhaust flow via a lean sorbent to produce a CO2 lean exhaust flow, flowing the second vapor flow into a steam reboiler to heat a water flow and produce a steam flow at a steam flow temperature and a steam flow pressure, flowing the steam flow into a sorbent heat exchanger of a desorption unit to heat a rich sorbent and condensing the steam flow back into the water flow, returning the water flow back into the steam reboiler, extracting CO2from the rich sorbent during a sorbent regeneration process to create a flow of CO2, releasing the CO2 lean exhaust flow to the atmosphere as vented exhaust.

[0018] In one embodiment, the method may also include where the first fluid flow is an organic fluid.

[0019] In one embodiment, the method may also include where the first fluid flow is super critical CO2 (sCCh). Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0020] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0021] FIG. 1 illustrates a prior art carbon capture process with an external power generation unit.

[0022] FIG. 2 illustrates an embodiment that utilizes the Rankin cycle with a waste heat recovery unit to operate a carbon capture unit with a CO2 compressor.

[0023] FIG. 3 illustrates an embodiment that utilizes the Rankin cycle with a waste heat recovery unit to operate a carbon capture unit.

[0024] FIG. 4 illustrates another embodiment that utilizes the Rankin cycle with a waste heat recovery unit to operate a carbon capture unit with a CO2 compressor.

[0025] FIG. 5 illustrates another embodiment that utilizes the Rankin cycle with a waste heat recovery unit to operate a carbon capture unit.

[0026] FIG. 6 illustrates an embodiment that utilizes the Organic Rankin or SCO2 cycle with a waste heat recovery unit to operate a carbon capture unit with a CO2 compressor.

[0027] FIG. 7 illustrates an embodiment that utilizes the Organic Rankin or SCO2 cycle with a waste heat recovery unit to operate a carbon capture unit.

[0028] FIG. 8 illustrates an embodiment of the present invention for use with a CO2 containing gas. DETAILED DESCRIPTION

[0029] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0030] Various technologies that pertain to apparatus and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus.

[0031] It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0032] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0033] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0034] Also, unless specified or limited otherwise, the terms “mounted”, “connected”, “supported”, and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

[0035] In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard as available a variation of 20 percent would fall within the meaning of these terms unless otherwise stated.

[0036] FIG. 1 is an example of a prior art carbon capture and storage process 100 that utilizes a waste heat source 104 that is upstream from the carbon capture and storage process 100. The waste heat source 104 can be a captive power plant 102 or another industrial process that produces a heated exhaust flow that is sent to an exhaust recovery unit 106 where it is used to heat a cooled flow 114 to produce a heated flow 116. The blower 108 circulates the exhaust flow from the exhaust recovery unit 106 to an absorber 110 where the lean sorbent 118 absorbs CO2 from the exhaust flow. The heated flow 116 is circulated to a heat exchanger 122 where it heats a rich sorbent 120.t. In the desorption unit 112 the heated rich sorbent 120 releases CO2 and is circulated back to the absorber 110 as lean sorbent 118. The CO2 can be circulated directly to storage or in some embodiments the CO2 is sent to a compressor 126 prior to storage or output 128 from the carbon capture and storage process 100. A captive power plant 102 is necessary for the carbon capture and storage process 100 as electricity may not be generated by the exhaust recovery unit 106 or an insufficient amount to fully operate the CCS process 100. Additionally, as the waste heat source 104 is upstream of the carbon capture and storage process 100 it is not intended to operate at an interval necessary for the continuous operation of the carbon capture and storage process 100. Even when the waste heat source 104 is in operation, the carbon capture and storage process 100 requires electricity from the captive power plant 102 to operate. These embodiments supplement or reduce the amount of electricity required to operate the carbon capture and storage process 100 but fail to extract the full amount of potential waste heat and reuse all of the usable waste heat available for other internal usage or recycle process.

[0037] In the embodiments seen in FIG. 2 and FIG. 3 a carbon capture process 200 is shown that utilizes the steam Rankine cycle to extract heat energy from a heated exhaust flow 204 of a waste heat source 202. In these embodiments the steam turbine 212 is an extraction turbine or other turbine that produces an extraction flow or second steam flow 216 and an outlet flow 218. The waste heat source 202 can be any number of industrial processes that produce a heated exhaust flow 204, including the exhaust from a turbine or reciprocating internal combustion engine (RICE). The heated exhaust flow 204 can have a temperature range between 300°C and 500°C. Inside of the waste heat recovery unit 210 the heated exhaust flow 204 boils a first water flow 258 and generates a first steam flow 208 at a first steam pressure and a first steam temperature. The first steam temperature can be between 280°C and 480°C with a first steam pressure between 12 and 35 bars absolute. Upon exiting the waste heat recovery unit 210 the cooled exhaust flow 206 can be returned to the waste heat source 202 as an industrial reuse 240 or diverted to an absorption unit 228 via an ID fan 230. The temperature of the cooled exhaust flow 206 is between 160-220°C if sent to industrial reuse 240 or can be between 80-220°C if sent to the absorption unit 228. Once in the absorption unit 228 the cooled exhaust flow 206 is exposed to a lean solvent or sorbent 254 which absorbs CO2 from the cooled exhaust flow 206. A CO2 lean exhaust flow 232 and rich solvent or sorbent 256 exit the absorption unit 228. The CO2 lean exhaust flow 232 can then be vented to the atmosphere via an exhaust stack 234 and the rich solvent 256 is sent to the desorption unit 226. The CO2 lean exhaust flow 232 can have a temperature between 60-140°C.

[0038] The first steam flow 208 is circulated to a steam turbine 212 where it spins the steam turbine 212 and a generator 214 coupled to the steam turbine 212 to generate electricity. The steam turbine 212 can be a back pressure turbine, an extraction turbine or any known turbine that lowers a pressure and temperature of an input steam flow while generating mechanical work. The steam turbine 212 produces all of the electricity required by all of the processes and auxiliaries of the carbon capture process 200 and may produce additional electricity required for the waste heat source 202 or a process plant or additional electricity can be exported to the electrical grid. In this embodiment the steam turbine 212 has an extraction steam flow or second steam flow 216 that has a second steam temperature between 120-140°C and a second steam pressure between 2-4 bars absolute. The second steam flow 216 is circulated to the sorbent heat exchanger 224 of the desorption unit 226 and heats the rich solvent 256 during a desorption cycle which causes the rich solvent 256 to release CO2, after releasing CO2 the now lean solvent 254 is returned to the absorption unit 228, a second water flow 260 and a CO2 flow 248 exit the desorption unit 226. The sorbent heat exchanger 224 can be integrated into the desorption unit 226 or can be an external unit. The inlet of the sorbent heat exchanger 224 receives the second steam flow 216 at the expected temperature range of 120-140°C and pressure range of 2-4 bar absolute, the cooled or condensed output or second water flow 260 is at a temperature range of 110-135°C and pressure range of 2-6 bar absolute.

[0039] The steam turbine 212 has an outlet flow 218 at an outlet temperature and outlet pressure. The outlet pressure is between 30-69°C and the outlet pressure is between 0.05-0.3 bars absolute. The outlet flow 218 is at or near a condensation state of water and a condenser is not necessary to return the outlet flow 218 back to a liquid state as it is circulated to a water reservoir 220. An output of the water reservoir 220 is joined with the second water flow 260 to produce a combined water flow 264. The combined water flow 264 is circulated to a pump 222 which supplies the waste heat recovery unit 210 with the first water flow 258. The combined water flow 264 can have a temperature between 30-110°C and a pressure between 2-6 bar absolute. Like the outlet flow 218 the combined water flow 264 is at or near the condensation or liquid state of water and does not require a dedicated condenser to return all or the majority of the combined water flow 264 to the liquid state prior to reaching the pump 222. In some embodiments the water reservoir 220 and the piping or tubing connecting the water reservoir 220 with the pump 222 are designed to act as heat sinks that help to condense the combined water flow 264. After exiting the pump 222 the first water flow 258 has a temperature between 30-110°C and a pressure between 14 and 40 bar absolute.

[0040] In the embodiment seen in FIG. 2, the carbon capture process 200 has a compressor 252 that compresses the CO2 flow 248 prior to storage or output. The compressor 252 generates heat or compression heat that is recovered by circulating a cooling water flow 262 to the compressor 252 and returning the cooling water flow 262 back to the second steam temperature and the second steam pressure. The compressor 252 can have an integrated or external HEX for circulation of the cooling water flow 262. The heat of compression can be between a range of 50-70°C. The output of the heat pump 242 supplements the second steam flow 216 and can be at a temperature between 120-140°C and a pressure between 2-6 bar absolute. In some embodiments a supplemental heat exchanger 244 is used to maintain the second steam temperature and second steam pressure. In some embodiments an additional heat source 246 can be used to return the cooling water flow 262 back to the second steam temperature and second steam pressure. In this embodiment a portion of the combined water flow 264 is circulated to the pump 222 and the remainder is circulated to the heat pump 242 as the cooling water flow 262.

[0041] In the embodiments seen in FIG. 4 and FIG. 5 a carbon capture process 200 is shown that utilizes the steam Rankine cycle with a backflow steam turbine or other turbine to extract heat energy from a heated exhaust flow 204 of a waste heat source 202. The waste heat source 202 can be any number of industrial processes that produce a heated exhaust flow 204, including the exhaust from a turbine or reciprocating internal combustion engine (RICE). The heated exhaust flow 204 can have a temperature range between 300°C and 500°C. Inside of the waste heat recovery unit 210 the heated exhaust flow 204 boils a first water flow 258 and generates a first steam flow 208 at a first steam pressure and a first steam temperature. The first steam temperature can be between 280°C and 480°C with a first steam pressure between 12 and 35 bars absolute. Upon exiting the waste heat recovery unit 210 the cooled exhaust flow 206 can be returned to the waste heat source 202 as an industrial reuse 240 or diverted to an absorption unit 228 via an ID fan 230. The temperature of the cooled exhaust flow 206 is between 160-220°C if sent to industrial reuse 240 or can be between 80-220°C if sent to the absorption unit 228. Once in the absorption unit 228 the cooled exhaust flow 206 is exposed to a lean solvent or sorbent 254 which absorbs CO2 from the cooled exhaust flow 206. A CO2 lean exhaust flow 232 and rich solvent or sorbent 256 exit the absorption unit 228. The CO2 lean exhaust flow 232 can then be vented to the atmosphere via an exhaust stack 234 and the rich solvent 256 is sent to the desorption unit 226. The CO2 lean exhaust flow 232 can have a temperature between 60-140°C.

[0042] The first steam flow 208 is circulated to a steam turbine 212 where it spins the steam turbine 212 and a generator 214 coupled to the steam turbine 212 to generate electricity. The steam turbine 212 can be a back pressure turbine, an extraction turbine or any known turbine that lowers a pressure and temperature of an input steam flow while generating mechanical work. The steam turbine 212 produces all of the electricity required by all of the processes and auxiliaries of the carbon capture process 200 and may produce additional electricity required for the waste heat source 202 or a process plant or additional electricity can be exported to the electrical grid.

[0043] The steam turbine 212 has an outlet flow 218 at an outlet temperature and outlet pressure. The outlet flow 218 is circulated to the sorbent heat exchanger 224 of the desorption unit 226 and heats the rich solvent 256 during a desorption cycle which causes the rich solvent 256 to release CO2, after releasing CO2 the now lean solvent 254 is returned to the absorption unit 228, a second water flow 260 and a CO2 flow 248 exit the desorption unit 226. The sorbent heat exchanger 224 can be integrated into the desorption unit 226 or can be an external unit. The inlet of the sorbent heat exchanger 224 receives the outlet flow 218 at the expected temperature range of 120-140°C and pressure range of 2-4 bar absolute, the cooled or condensed output or second water flow 260 is at a temperature range of 110-135°C and pressure range of 2-6 bar absolute. The outlet flow 218 is at or near a condensation state of water and a condenser is not necessary to return the outlet flow 218 back to a liquid state as it is circulated to a water reservoir 220. The water reservoir 220 can be a tank or similar containment vessel or simply be the piping and tubing between the pump 222 and sorbent heat exchanger 224. In this embodiment, the output of the water reservoir 220 is joined with the second water flow 260 and referred to as combined water flow 264. The combined water flow 264 is circulated to a pump 222 which supplies the waste heat recovery unit 210 with the first water flow 258. The combined water flow 264 can have a temperature between 30-110°C and a pressure between 2-6 bar absolute. Like the outlet flow 218 the combined water flow 264 is at or near the condensation or liquid state of water and does not require a dedicated condenser to return all or the majority of the combined water flow 264 to the liquid state prior to reaching the pump 222. In some embodiments the water reservoir 220 and the piping or tubing connecting the water reservoir 220 with the pump 222 are designed to act as heat sinks that help to condense the combined water flow 264. After exiting the pump 222 the first water flow 258 has a temperature between 30-110°C and a pressure between 14 and 40 bar absolute.

[0044] In the embodiment seen in FIG. 4, the carbon capture process 200 has a compressor 252 that compresses the CO2 flow 248 prior to storage or output. The compressor 252 generates heat or compression heat that is recovered by circulating a cooling water flow 262 to the compressor 252 and returning the cooling water flow 262 back to the outlet temperature and the outlet pressure. The compressor 252 can have an integrated or external HEX for circulation of the cooling water flow 262. The heat of compression can be between a range of 50-70°C. The output of the heat pump 242 supplements the outlet flow 218 and can be at a temperature between 120-140°C and a pressure between 2-6 bar absolute. In some embodiments a supplemental heat exchanger 244 is used to maintain the outlet temperature and outlet pressure. In some embodiments an additional heat source 246 can be used to return the cooling water flow 262 back to the outlet temperature and outlet pressure. In this embodiment a portion of the second water flow 260 is circulated to the reservoir 220 and the remainder is circulated to the heat pump 242 as the cooling water flow 262.

[0045] In the embodiments seen in FIG. 6 and FIG. 7 a carbon capture process 200 is shown that utilizes an organic Rankine cycle or a super critical CO2 cycle to extract heat energy from a heated exhaust flow 204 of a waste heat source 202. The waste heat source 202 can be any number of industrial processes that produce a heated exhaust flow 204, including the exhaust from a turbine or RICE. The heated exhaust flow 204 can have a temperature range between 300°C and 500°C. Inside of the waste heat recovery unit 210 the heated exhaust flow 204 transfers heat energy to a heat transfer media, including any known thermic fluid. The heat transfer media or fluid exits the waste heat recovery unit 210 as a heated transfer media 602 at a first media pressure and a first media temperature. The heated transfer media 602 enters a primary heat exchanger 604 and exits as a cooled transfer media 624 at a second media temperature and pressure. The first media temperature can be between 280-390°C with a first media pressure between 6-8 bars absolute and the second media temperature can be in a range between of 120-160°C and the second media pressure can be between 6-8 bar absolute. Upon exiting the waste heat recovery unit 210 the cooled exhaust flow 206 can be returned to the waste heat source 202 as an industrial reuse 240 or diverted to an absorption unit 228 via an ID fan 230. The temperature of the cooled exhaust flow 206 is between 160-220°C if sent to industrial reuse 240 or can be between 80-220°C if sent to the absorption unit 228. Once in the absorption unit 228 the cooled exhaust flow 206 is exposed to a lean solvent or sorbent 254 which absorbs CO2 from the cooled exhaust flow 206. A CO2 lean exhaust flow 232 and rich solvent or sorbent 256 exit the absorption unit 228. The CO2 lean exhaust flow 232 can then be vented to the atmosphere via an exhaust stack 234 and the rich solvent 256 is sent to the desorption unit 226. The CO2 lean exhaust flow 232 can have a temperature between 60-140°C.

[0046] The primary heat exchanger 604 heats an organic fluid or SCO2 and generates a first vapor flow 610 with a first vapor temperature and a first vapor pressure. In embodiments that utilize an organic fluid the first vapor temperature can be in a range between 80-260°C and the first vapor pressure can be in a range between 12-40 bar absolute. In embodiments that utilize SCO2 the first vapor temperature can be in a range between 250-370°C and the first vapor pressure can be in a range between 150-200 bar absolute.

[0047] The first vapor flow 610 is circulated to a turbine 612 where it spins the turbine 612 and a generator 214 coupled to the turbine 612 to generate electricity. The turbine 612 can be a back pressure turbine, an extraction turbine or any known turbine that lowers a pressure and temperature of an input vapor flow while generating mechanical work. The turbine 612 produces all of the electricity required by all of the processes and auxiliaries of the carbon capture process 200. The turbine 612 produces an output flow or extraction flow or second vapor flow 614 with a second vapor pressure and a second vapor temperature. In embodiments that utilize an organic fluid the second vapor temperature can be in a range between 120-140°C and the second vapor pressure can be in a range between 5-8 bar absolute. In embodiments that utilize sCCh the second vapor temperature can be in a range between 120-140°C and the second vapor pressure can be in a range between 80-90 bar absolute. The second vapor flow 614 is circulated through the steam reboiler 616. The steam reboiler 616 heats a water flow 618 to produce a steam flow 620. The second vapor flow 614 exits the steam reboiler 616 as a condensate flow 626 with a condensate temperature and condensate pressure. In embodiments that utilize an organic fluid the condensate temperature can be in a range between 40-50°C and the condensate pressure can be in a range between 5-8 bar absolute. In embodiments that utilize SCO2 the condensate temperature can be in a range between 20-30°C and the condensate pressure can be in a range between 80-90 bar absolute.

[0048] The condensate flow 626 is circulated into a reservoir 606. An output of the reservoir 606 is circulated to a feed pump 628 which supplies the primary heat exchanger 604 with the first fluid flow 608. The first fluid flow 608 has a first fluid flow temperature and a first fluid flow pressure. In embodiments that utilize an organic fluid the first fluid flow temperature can be in a range between 40-50°C and the first fluid flow pressure can be in a range between 14-45 bar absolute. In embodiments that utilize SCO2 the first fluid flow temperature can be in a range between 20-30°C and the first fluid flow pressure can be in a range between 170-210 bar absolute. The condensate flow 626 is at or near the condensation or liquid state of the organic fluid or sCO22 used by the carbon capture process 200 and does not require a dedicated condenser to return all or the majority of the condensate flow 626 to the liquid state prior to reaching the feed pump 628. In some embodiments the reservoir 606 and the piping or tubing connecting the reservoir 606 with the feed pump 628 are designed to act as heat sinks that help to condense the condensate flow 626.

[0049] The sorbent heat exchanger 224 of the desorption unit 226 heats the rich solvent 256 during a desorption cycle which causes the rich solvent 256 to release CO2, after releasing CO2 the now lean solvent 254 is returned to the absorption unit 228, a water flow 618 and a CO2 flow 248 exit the desorption unit 226. The sorbent heat exchanger 224 can be integrated into the desorption unit 226 or can be an external unit. The inlet of the sorbent heat exchanger 224 receives the steam flow 620 at the expected temperature range of 120-140°C and pressure range of 2-4 bar absolute, the cooled or condensed output of the sorbent heat exchanger 224 can be at a temperature range of 110-135°C and pressure range of 2-6 bar absolute.

[0050] In the embodiment seen in FIG. 6, the carbon capture process 200 has a compressor 252 that compresses the CO2 flow 248 prior to storage or output. The compressor 252 generates heat or compression heat that is recovered by circulating a portion of the water flow 618 to the compressor 252 and returning the water flow 618 back to the steam temperature and the steam pressure. The compressor 252 can have an integrated or external HEX for circulation of the cooling water flow 622. The heat of compression can be between a range of 50-70°C. The output of the heat pump 242 supplements the steam flow 620 and can be at a temperature between 120-140°C and a pressure between 2-6 bar absolute. In some embodiments a supplemental heat exchanger 244 is used to maintain the steam temperature and steam pressure. In some embodiments an additional heat source 246 can be used to return the water flow 618 back to the steam temperature and steam pressure.

[0051] In the embodiment seen in FIG. 8 a variation of the carbon capture process 200 is shown that extracts CO2 from a CO2 containing gas 802 and the heated flow or heated exhaust flow 204 after it has been circulated through the waste heat recovery unit 210. A CO2 containing gas 802 is circulated to the absorption unit 228 and CO2 is extracted from the CO2 containing gas 802 during an absorption process. The CO2 containing gas 802 can be atmospheric air, the exhaust from another industrial process that does not supply the heated exhaust flow 204, or any CO2 containing gas. After the absorption process the post absorption gas 804 is vented to the atmosphere via the exhaust stack 234. This embodiment can be used with any of the previously presented embodiments. In another embodiment the electricity produced by the carbon capture process 200 that is not used to operate the carbon capture process 200 is directed to a direct air carbon capture unit. An exhaust damper 238 or damper(s) 238 can be integrated into the heated exhaust flow 204 and or the cooled exhaust flow 206 lines or piping.

[0052] Although various embodiments that incorporate disclosed concepts have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these disclosed concepts. Disclosed embodiments are not limited to the specific details of construction and the arrangement of components set forth in the description or illustrated in the drawings. Disclosed concepts may be implemented by other implementations, and of being practiced or of being carried out m various ways, which now would become apparent to one skilled in the art.

[0053] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

What is claimed is:

1. A method of capturing carbon from a heated flow (204) utilizing waste heat recovery with a carbon capture process (200) comprising the steps:diverting the heated flow (204) from a waste heat source (202) and circulating the heated exhaust flow (204) through a waste heat recovery unit (210) to produce a cooled exhaust flow (206),pumping a first water flow (258) from a combined water flow (264) via a pump (222) into the waste heat recovery unit (210) and generating a first steam flow (208) at first steam temperature and a first steam pressure,flowing the first steam flow (208) into a steam turbine (212) to create a second steam flow (216) with a second steam temperature and a second steam pressure, rotating the steam turbine (212) and an electrical generator (214) with the first steam flow (208) to produce an amount of electrical energy,powering the carbon capture process (200) with a portion of the electrical energy produced by the electrical generator (214),circulating an amount of the cooled exhaust flow (206) to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),flowing the second steam flow (216) to a sorbent heat exchanger (224) of a desorption unit (226) to heat a rich sorbent (256), condensing the second steam flow (216) into a second water flow (260),flowing an outlet flow (218) at an outlet temperature and an outlet pressure from the steam turbine (212) to the water reservoir (220),combining the second water flow (260) with an output of the water reservoir (220) to create the combined water flow (264),flowing the combined water flow (264) into the pump (222),extracting CO2from the rich sorbent (256) during a sorbent regeneration process to create a flow of CO2 (248),releasing the CO2 lean exhaust flow (232) to the atmosphere as vented exhaust (236).

2. The method of claim 1 further comprising,flowing a portion of the combined water flow (264) into the pump (222) and diverting the remainder to a heat pump (242) as a cooling water flow (262),compressing the flow of CO2 (248) in a compressor (252) to create an amount of compressed CO2 (250) and an amount of compression heat,cooling the compressor (252) with the cooling water flow (262), re-boiling the cooling water flow (262) by transferring the compression heat to the cooling water flow (262) via a heat pump (242) and returning the cooling water flow (262) to the second steam temperature and second steam pressure,supplementing the second steam flow (216) with an output of the heat pump (242).

3. The method of claim 1 further comprising, circulating an amount of the cooled exhaust flow (206) back to the waste heat source (202) for a reuse (240) and circulating the remainder to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232).

4. The method of claim 1 further comprising, replacing the water reservoir (220) with a condenser and condensing the combined water flow (264) prior to entering the pump (222).

5. The method of claim 1 further comprising, supplying the grid or an industrial process with an amount of electricity produced by the generator (214).

6. The method of claim 1 further comprising, replacing or combining the cooled exhaust flow (206) with a CO2 containing gas (802) and circulating the CO2 containing gas (802) to the absorption unit (228) and absorbing CO2 from the CO2 containing gas (802) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),venting the post absorption gas (804) to the atmosphere.

7. A method of capturing carbon from a heated flow (204) utilizing waste heat recovery with a carbon capture process (200) comprising the steps:diverting the heated flow (204) from a waste heat source (202) and circulating the heated flow (204) through a waste heat recovery unit (210) to produce a cooled exhaust flow (206),pumping a first water flow (258) from a combined water flow 264 via a pump (222) into the waste heat recovery unit (210) and generating a first steam flow (208) at a first steam temperature and a first steam pressure,flowing the first steam flow (208) into a steam turbine (212) to create an outlet flow (218) with a second steam temperature and a second steam pressure, rotating the steam turbine (212) and an electrical generator (214) with the first steam flow (208) to produce an amount of electrical energy,powering the carbon capture process (200) with a portion of the electrical energy produced by the electrical generator (214),circulating an amount of the cooled exhaust flow (206) to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),flowing the outlet flow (218) to a sorbent heat exchanger (224) of a desorption unit (226) to heat a rich sorbent (256), condensing the outlet flow (218) into a second water flow (260),flowing the second water flow (260) to a water reservoir (220),combining the second water flow (260) with the contents of the water reservoir (220) to create the combined water flow (264),flowing the combined water flow (264) into the pump (222),extracting CO2 from the rich sorbent (256) during a sorbent regeneration process to create a flow of CO2 (248),releasing the CO2 lean exhaust flow (232) to the atmosphere as vented exhaust (236).

8. The method of claim 7 further comprising,flowing a portion of the combined water flow (264) into the pump (222) and diverting the remainder to a heat pump (242) as a cooling water flow (262),compressing the flow of CO2 (248) in a compressor (252) to create an amount of compressed CO2 (250) and an amount of compression heat,cooling the compressor (252) with the cooling water flow (262), re-boiling the cooling water flow (262) by transferring the compression heat to the cooling water flow (262) via aheat pump (242) and returning the cooling water flow (262) to the second steam temperature and second steam pressure,supplementing the outlet flow (218) with an output of the heat pump (242).

9. The method of claim 7 further comprising,circulating an amount of the cooled exhaust flow (206) back to the waste heat source (202) for a reuse (240) and circulating the remainder to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232).

10. The method of claim 7 further comprising,replacing the water reservoir (220) with a condenser and condensing the combined water flow (264) prior to entering the pump (222).

11. The method of claim 7 further comprising, supplying the grid or an industrial process with an amount of electricity produced by the generator (214).

12. The method of claim 7 further comprising,replacing the cooled exhaust flow (206) with a CO2 containing gas (802) and circulating the CO2 containing gas (802) to the absorption unit (228) and absorbing CO2 from the CO2 containing gas (802) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),venting the post absorption gas (804) to the atmosphere.

13. A method of capturing carbon from a heated exhaust flow (204) utilizing waste heat recovery with a carbon capture process (200) comprising the steps:diverting the heated flow (204) from a waste heat source (202) and circulating the heated flow (204) through a waste heat recovery unit (210) to produce a cooled exhaust flow (206),circulating a thermic fluid (602) between the waste heat recovery unit (210) and a heat exchanger (604),pumping a first fluid flow (608) from a thermic fluid reservoir (606) via a feed pump (628) into the heat exchanger (604) and generating a first vapor flow (610) at a first vapor temperature and a first vapor pressure,flowing the first vapor flow (610) into a turbine (612) to create a second vapor flow (614) with a second vapor temperature and a second vapor pressure, rotating the turbine (612) and an electrical generator (214) with the first vapor flow (610) to produce an amount of electrical energy,powering the carbon capture process (200) with an amount of the electrical energy produced by the electrical generator (214),circulating an amount of the cooled exhaust flow (206) to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),flowing the second vapor flow (614) into a steam reboiler (616) to heat a water flow (618) and produce a steam flow (620) at a steam flow temperature and a steam flow pressure,flowing the steam flow (620) into a sorbent heat exchanger (224) of a desorption unit (226) to heat a rich sorbent (256) and condensing the steam flow (620) back into the water flow (618), returning the water flow (618) back into the steam reboiler (616),extracting CO2 from the rich sorbent (256) during a sorbent regeneration process to create a flow of CO2 (248),releasing the CO2 lean exhaust flow (232) to the atmosphere as vented exhaust (236).

14. The method of claim 13 wherein the first fluid flow is an organic fluid.

15. The method of claim 13 wherein the first fluid flow is super critical CO2 (sCO?).

16. The method of claim 13 further comprising,flowing the steam flow (620) into a sorbent heat exchanger (224) of a desorption unit (226) to heat a rich sorbent (256) and returning a portion of the water flow (618) back into the steam reboiler (616) and diverting the remainder to a heat pump (242) as a cooling fluid flow (622),cooling the compressor (252) with the cooling fluid flow (622), re-boiling the cooling fluid flow (622) by transferring the compression heat to the cooling fluid flow (622) via a heat pump (242) and returning the cooling water flow (622) to the steam flow temperature and the steam flow pressure,supplementing the steam flow (620) with an output of the heat pump (242).

17. The method of claim 13 further comprising,circulating an amount of the cooled exhaust flow (206) back to the waste heat source (202) for a reuse (240) and circulating the remainder to an absorption unit (228) and absorbing CO2 from the cooled exhaust flow (206) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232).

18. The method of claim 13 further comprising,replacing the reservoir (606) with a condenser and condensing the condensate flow (626) prior to entering the feed pump (628).

19. The method of claim 13 further comprising, supplying the grid or an industrial process with an amount of electricity produced by the generator (214).

20. The method of claim 13 further comprising,replacing or combining the cooled exhaust flow (206) with a CO2 containing gas 802 and circulating the CO2 containing gas (802) to the absorption unit (228) and absorbing CO2 from the CO2 containing gas (802) via a lean sorbent (254) to produce a CO2 lean exhaust flow (232),venting the post absorption gas (804) to the atmosphere.

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