Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
  • B01D53/1456—Removing acid components
  • B01D53/1475—Removing carbon dioxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
  • B01D53/1425—Regeneration of liquid absorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2251/00—Reactants
  • B01D2251/60—Inorganic bases or salts
  • B01D2251/606—Carbonates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
  • B01D2252/20—Organic absorbents
  • B01D2252/204—Amines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2258/00—Sources of waste gases
  • B01D2258/02—Other waste gases
  • B01D2258/0233—Other waste gases from cement factories
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2258/00—Sources of waste gases
  • B01D2258/02—Other waste gases
  • B01D2258/0283—Flue gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2259/00—Type of treatment
  • B01D2259/65—Employing advanced heat integration, e.g. Pinch technology
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present disclosure relates to a system and process for capturing carbon dioxide from flue gas using carbon dioxide absorbent capture media.
• SO x sulfur oxides
• NO x nitrogen oxides
• H 2 S hydrogen sulfide
• H 2 S hydrogen chloride
• HF hydrogen fluoride
• C0 2 carbon dioxide
• the amount of C0 2 present in flue gas can be reduced by strategies such as burning less coal, improving the efficiency of coal-fired power plants and capturing, followed by storing the captured C0 2 .
• C0 2 capture techniques such as pre- combustion, post combustion and oxy-combustion
• post combustion carbon capture techniques are the most effective since they do not require any extensive rebuilding of the existing process plant.
• US 20120312020 discloses an apparatus and a method for regeneration of the capture media such as an absorption solution and recovery of the absorbed gas from the capture media. US 20120312020 further discloses an apparatus and method for the removal and recovery of a target gas from a gas stream and its application in post combustion carbon capture in a thermal power l plant. However, the process of US 20120312020 employs heating means such as reboilers that increase the operating cost.
• the conventional absorption techniques for C0 2 capture are associated with several drawbacks such as high energy requirement for capturing carbon dioxide and amine regeneration (2.5 - 4.0 GJ/ton) and oxidative degradation that reduces the overall efficiency of the power plant by up to 13%.
• Most of the processes for capturing carbon dioxide from air or flue gas stream utilize heat from an external source together with the heat made available by compressing the desorbed vapor product (pure carbon dioxide).
• this type of heat utilization does not significantly increase the cost-efficiency of the process.
• the present disclosure provides a multi-compression process for capturing carbon dioxide (CO 2 ) from a flue gas stream containing CO 2 ; said process comprising the following steps: i. directing the flow of the flue gas stream through a blower (B) to obtain a pressurized flue gas stream with elevated temperature; ii. extracting the heat from the pressurized flue gas stream in a first heat exchanger (Hex-B) using circulating thermic fluid to obtain a heated thermic fluid and a cooled pressurized flue gas stream; iii. directing the cooled pressurized flue gas stream to a CO 2 absorber (A); iv.
• the rich capture media stream emerging from the absorber (A) can be directed to the second heat exchanger (Hex-E) via a first pump (PI).
• the adsorption reaction in the adsorber (A) takes place efficiently at a temperature ranging from 50-70 °C.
• the heated rich capture media emerging from the second heat exchanger (Hex-E) can be directed to a third separator (S3) to separate the generated C0 2 gas and the rich capture media, said separated C0 2 gas being converged along with the C0 2 rich vapor mixture emerging from the desorber (D) in a second converger (Cv2) to provide a converged stream and said rich capture media being directed to the desorber (D).
• S3 third separator
• Cv2 second converger
• the converged stream can be passed through the condenser (Cd) to obtain a two-phase mixture, followed by separating the two-phase mixture in the first separator (SI) to obtain condensate and pure C0 2 gas, said condensate being recycled to the desorber (D) and said pure C0 2 gas being isolated for further processing.
• Cd condenser
• SI first separator
• the condensate emerging from the first separator (S I) can be passed through a second pump (P2) before entering the desorber (D).
• the rich capture media upon heating in the desorber (D) drives off a pre-determined quantity of water, said pre-determined quantity of water exits the desorber (D), gets heated in the third heat exchanger (Hex-C) to provide steam, said steam re-enters the desorber (D) to aid the desorption of C0 2 from the rich capture media.
• the heated rich capture media in the desorber (D) may be heated to a temperature ranging from ISO- ISO °C for efficiently desorbing C0 2 from the heated rich capture media.
• the lean, hot capture media stream emerging from the third heat exchanger (Hex-C), can pass through a third pump (P3), before entering the second heat exchanger (Hex- E).
• the non-thermic fluid can be circulated by heating the non-thermic fluid emerging from the third heat exchanger (Hex-C) with the help of external heat source (IN) in the fifth heat exchanger (Hex-A) and further heating the non-thermic fluid in a sixth heat exchanger (Hex-F) where-after, the heated non-thermic fluid is fully pressurized and vaporized and at an elevated pressure and temperature, is supplied to the third heat exchanger (Hex-C) for heating the lean capture media stream emerging from the desorber (D).
• Hex-C third heat exchanger
• IN external heat source
• the non-thermic fluid emerging from the third heat exchanger (Hex-C) can be passed through a valve (V) before entering the fifth heat exchanger (Hex-A).
• the vapor and liquid exiting the fifth heat exchanger (Hex-A) are separated using a second separator (S2) and only the liquid portion is supplied to the sixth heat exchanger (Hex-F).
• the vapor collected from the second separator (S2) and vapor emanating from the sixth heat exchanger (Hex-F) can be converged in a first converger (Cvl) before being compressed in a booster compressor (BC) for supply to the third heat exchanger (Hex- C).
• the thermic fluid can be circulated using a thermic fluid cycle in which the thermic fluid is heated using compressed flue gas in the first heat exchanger (Hex-B), the heated thermic fluid is supplied to the sixth heat exchanger (Hex-F) where it loses heat to the circulating heated, vaporized non-thermic fluid, resulting in the emanation of warm thermic fluid from the sixth heat exchanger (Hex-F) which is further cooled by external cold water in a seventh heat exchanger (Hex-G) for reiteration through the first heat exchanger (Hex-B).
• a thermic fluid cycle in which the thermic fluid is heated using compressed flue gas in the first heat exchanger (Hex-B), the heated thermic fluid is supplied to the sixth heat exchanger (Hex-F) where it loses heat to the circulating heated, vaporized non-thermic fluid, resulting in the emanation of warm thermic fluid from the sixth heat exchanger (Hex-F) which is further
• the lean, warm capture media stream emerging from the second heat exchanger (Hex- E) can be cooled in the fourth heat exchanger (Hex-D) with the help of external supply of cold water for supplying the cool lean capture media stream to the absorber (A).
• the capture media can be an aqueous solution of at least one inorganic metal carbonate or at least one amine, wherein said amine is selected from the group consisting of primary amine, secondary amine, tertiary amine, and mixtures thereof.
• the non-thermic fluid can be at least one selected from the group consisting of water, methanol, acetone, and propanol.
• the present disclosure further provides a multi-compression system for capturing carbon dioxide (C0 2 ) from a flue gas stream having C0 2 ; said system comprising: i. a blower (B) adapted to receive the flue gas stream and pressurize said flue gas stream to generate a pressurized flue gas stream with elevated temperature; ii. a first heat exchanger (Hex-B) adapted to receive said pressurized flue gas stream and thermic fluid and transfer heat from said pressurized flue gas stream to said thermic fluid to obtain heated thermic fluid and a cooled pressurized flue gas stream; iii.
• a blower B
• Hex-B first heat exchanger
• an absorber (A) adapted to receive said cooled pressurized flue gas stream and a cool and lean capture media stream, said cool and lean capture media stream adapted to absorb C0 2 to generate a rich capture media stream; iv. a second heat exchanger (Hex-E) adapted to receive said rich capture media stream and heat said rich capture media stream to near a predefined regeneration temperature, to obtain a heated rich capture media stream; v. a desorber (D) adapted to receive said heated rich capture media stream and maintain heat therein to desorb C0 2 from said heated rich capture media stream to emit C0 2 rich vapor and a lean capture media stream; vi.
• a second heat exchanger (Hex-E) adapted to receive said rich capture media stream and heat said rich capture media stream to near a predefined regeneration temperature, to obtain a heated rich capture media stream
• v. a desorber (D) adapted to receive said heated rich capture media stream and maintain heat therein to desorb C0 2 from said heated rich capture media stream to
• a condenser (Cd) adapted to condense the C0 2 rich vapor emerging from the desorber (D) and provide a two phase mixture of C0 2 gas and condensate;
• a first separator (SI) adapted to receive the two phase mixture emerging from the condenser (Cd) and separate the pure C0 2 gas and condensate and direct said condensate to the desorber (D);
• a third heat exchanger (Hex-C) adapted to receive and heat the lean capture media stream exiting the desorber (D) and direct the lean, hot capture media to the second heat exchanger (Hex-E) to heat the rich capture media stream emerging from the absorber (A);
• a fourth heat exchanger (Hex-D) adapted to receive warm lean capture media stream from said second heat exchanger (Hex-E) and further adapted to transfer heat from said warm lean capture media stream to an external supply of cold water to emit cool lean capture media stream to be supplied to said absorber (A) for absorbing C0 2 from the flue gas stream;
• a non-thermic fluid cycle adapted to provide heat in the third heat exchanger (Hex-C) to heat the lean capture media stream emerging from the desorber (D); and xi. a thermic fluid cycle adapted to supply heat to the non-thermic fluid cycle; said thermic fluid cycle being driven by heat supplied by the pressurized flue gas stream received by the blower (B).
• the system can further comprise a first pump (PI) provided in-line between the absorber (A) and the second heat exchanger (Hex-E), adapted to pressurize the rich capture media stream emerging from the absorber (A).
• PI first pump
• Hex-E second heat exchanger
• the system can further comprise a third separator (S3) provided in-line between the second heat exchanger (Hex-E) and the desorber (D) and a second converger (Cv2) and the desorber (D), adapted to receive the heated rich capture media stream emerging from the second heat exchanger (Hex-E) and separate the generated C0 2 gas and the rich capture media.
• S3 third separator
• Hex-E second heat exchanger
• Cv2 second converger
• Cv2 second converger
• the second converger (Cv2) is provided in-line between the condenser (Cd) and the desorber (D) and the condenser (Cd) and the third separator (S3) and is adapted to converge the separated C0 2 gas emerging from the third separator (S3) and the C0 2 rich vapor mixture emerging from the desorber (D) and direct the converged stream to the condenser (Cd).
• the system can further comprise a second pump (P2) provided in-line between the first separator (SI) and the desorber (D), adapted to pressurize the condensate emerging from the first separator (SI).
• P2 second pump
• the system can further comprise a third pump (P3) provided in-line between the third heat exchanger (Hex-C) and the second heat exchanger (Hex-E), adapted to pressurize the lean, hot capture media stream emerging from the third heat exchanger (Hex-C).
• P3 third pump
• Hex-C third heat exchanger
• Hex-E second heat exchanger
• the third heat exchanger (Hex-C) is further adapted to receive a predetermined quantity of water emerging from the desorber (D), heat the predetermined quantity of water to provide steam and recycle said steam to the desorber (D).
• a second separator (S2) is provided in-line between the fifth heat exchanger (Hex-A) and the sixth heat exchanger (Hex-F) and is adapted to separate vapor and liquid exiting the fifth heat exchanger (Hex-A) and supply the liquid portion to the sixth heat exchanger (Hex-F).
• the non-thermic fluid cycle comprises a fifth heat exchanger (Hex-A) adapted to heat the non-thermic fluid emanating from the third heat exchanger (Hex-C) using external process heat (IN), a second separator (S2) adapted to separate liquid and vapor emanating from the fifth heat exchanger (Hex-A), a sixth heat exchanger (Hex-F) adapted to heat and vaporize the liquid received from the second separator (S2), a first converger (Cvl) for converging the vapors received from the second separator (SI) and from the sixth heat exchanger (Hex-F) and a booster compressor (BC) adapted to receive vapor from the first converger (Cvl) and adapted to vaporize, pressurize and heat the vapor for onward supply to the third heat exchanger (Hex-C) to heat the lean capture media stream emerging from the desorber (D).
• Hex-A fifth heat exchanger
• S2 adapted to separate liquid and vapor emanating from
• the system can further comprise a valve (V) provided in-line between the third heat exchanger (Hex-C) and the fifth heat exchanger (Hex-A) to de-pressurize the stream of non-thermic fluid emerging from the third heat exchanger (Hex-C).
• V valve
• the thermic fluid cycle comprises the blower (B) adapted to receive, heat and pressurize the flue gas stream containing C0 2 , the first heat exchanger (Hex-B) adapted to receive the heated and pressurized flue gas stream and cooled thermic fluid and further adapted to transfer heat from said flue gas stream to said cooled thermic fluid to emit cool, pressurized flue gas stream and hot thermic fluid, the sixth heat exchanger (Hex-F) adapted to receive the hot thermic fluid and transfer heat from the hot thermic fluid to the liquid component of the non-thermic fluid and emit warm thermic fluid and a seventh heat exchanger (Hex-G) adapted to receive the warm thermic fluid and further adapted to exchange heat in the warm thermic fluid with an external supply of cold water to emit cool thermic fluid for further reiteration in the cycle.
• the capture media can be an aqueous solution of at least one inorganic metal carbonate or at least one amine, wherein said amine is selected
• the non-thermic fluid can be at least one selected from the group consisting of water, methanol, acetone, and propanol.
• Fig. 1 illustrates a schematic diagram of a multi-compression system (100) for capturing carbon dioxide contained in flue gas using a carbon dioxide absorbent capture media.
• Fig. 2 illustrates a schematic diagram of a multi-compression system (100) including a first pump (PI), a second pump (P2), a third pump (P3), a valve (V), a second converger (Cv') and a third separator (S3) in accordance with one embodiment of the present disclosure.
• PI first pump
• P2 second pump
• P3 third pump
• V valve
• V second converger
• S3 third separator
• the present disclosure relates generally to the capture of carbon dioxide from a variety of flue gas sources including, without limitation, those from oil refineries, fossil fuel based power plants, cement plants and any other potential source of emissions.
• the invention of the present disclosure involves a multiple-compression cycle for compressing excess flue gas produced from the afore-stated sources that involves use of a high temperature heat transfer fluid (thermic fluid) for extracting the heat generated due to the compression and a heat pump for selective compression and expansion of a circulating non-thermic fluid that utilizes the process plant waste heat, together, for compensating the heat demand in the step of regeneration of the capture media.
• a high temperature heat transfer fluid thermo fluid
• the disclosure also provides a process for the regeneration of the carbon dioxide capture media.
• system (100) comprises the following components:
• the process of the present disclosure initially includes directing the flow of a hot flue gas stream, containing C0 2 , sourced from an external plant or apparatus, through a blower (B).
• the blower is employed to increase the pressure and the temperature of the flue gas stream.
• the pressurized flue gas stream from the blower (B) is passed through the first heat exchanger (Hex-B), which also receives a stream of cool thermic fluid.
• the cool thermic fluid stream extracts heat from the pressurized flue gas stream and a heated thermic fluid stream and a cooled pressurized flue gas stream are found to emerge from the first heat exchanger (Hex-B).
• the thermic fluid includes but is not limited to oils, hydrocarbon oils such as Dowtherm and glycols.
• the cooled pressurized flue gas stream is then directed to a C0 2 absorber (A), which also receives a cool and lean capture media stream.
• the cooled pressurized flue gas stream and the cool and lean capture media stream run counter current to each other.
• the lean capture media stream reacts chemically with the C0 2 gas in the incoming cooled pressurized flue gas stream to generate a stream of capture media rich in C0 2 as well as a treated flue gas stream devoid of C0 2 .
• the adsorption reaction in the adsorber (A) takes place efficiently at a temperature ranging from 50-70 °C.
• the capture media includes but is not limited to an aqueous solution of at least one inorganic metal carbonate or at least one amine, wherein said amine is selected from the group consisting of primary amine, secondary amine, tertiary amine, and mixtures thereof.
• the treated flue gas stream devoid of C0 2 is vented to the atmosphere, whereas the stream of capture media rich in C0 2 is directed to the second heat exchanger (Hex-E).
• the capture media rich in C0 2 emerging from the absorber (A) is directed to the second heat exchanger (Hex-E) via a first pump (PI). The pump is employed to increase the pressure of the capture media rich in C0 2 .
• the stream of capture media rich in C0 2 is heated in the second heat exchanger (Hex- E) to its regeneration temperature by a lean, hot capture media stream sourced from the third heat exchanger (Hex-C).
• the second heat exchanger (Hex-E) reduces the thermal load on the desorber (D) which is used downstream.
• a stream of a heated rich capture media results, which is further directed to the desorber (D) for complete regeneration.
• the stream of heated rich capture media that emerges from the second heat exchanger (Hex-E) is passed through a third separator (S3), before being directed to the desorber (D). This is done in order to separate the C0 2 gas generated from the rich capture media due to the increase in temperature.
• the separated rich capture media is directed further to the desorber (D).
• the desorber (D) at the regeneration temperature, desorbs the C0 2 gas from the heated rich capture media stream to separately yield a vapor mixture of steam and C0 2 gas and a lean capture media stream.
• the heated rich capture media in the desorber (D) may be heated to a temperature ranging from 130-150 °C for efficiently desorbing C0 2 from the heated rich capture media.
• the vapor mixture is passed through the condenser (Cd), where an external supply of cold water (C W) is provided for effecting partial condensation.
• the resulting two phase stream of C0 2 gas and condensate is separated in the first separator (SI) and the condensate (water) is refluxed back to the desorber (D).
• the vapor mixture emerging from the desorber (D) along with the separated C0 2 gas provided by the third separator (S3) are converged into a second converger (Cv2) to provide a converged stream.
• the converged stream is then forwarded to the condenser (Cd) to obtain a two-phase mixture.
• the condensate emerging from the first separator (SI) is passed through a second pump (P2) before entering the desorber (D).
• the lean capture media stream emerging from the desorber (D) is heated in the third heat exchanger (Hex-C) by utilization of latent heat of condensation of circulating compressed non-thermic fluid.
• the non-thermic fluid is selected from the group that includes but is not limited to water, methanol, acetone, and propanol.
• the non-thermic fluid has boiling point in range of 25 to 105 °C and workable under pressure range of 1 - 10 bar and also with higher latent heat of vaporization/condensation.
• a cool non-thermic fluid is heated by means of external heat source (IN) in the fifth heat exchanger (Hex-A) so that the non-thermic fluid partially vaporizes.
• the vapor and the liquid components of the non-thermic fluid stream are separated in a second separator (S2) after which, the liquid component is passed through a sixth heat exchanger (Hex-F).
• the previously mentioned stream of heated thermic fluid emerging from the first heat exchanger (Hex-B) is made to pass through the sixth heat exchanger (Hex-F), which vaporizes the liquid component of the non-thermic fluid stream.
• the vaporized non-thermic fluid emerging from the sixth heat exchanger (Hex-F) as well as the vaporized non-thermic fluid emerging from the second separator (S2) is passed through a first converger (Cvl).
• the converged vaporized non-thermic fluid emerging from the first converger (Cvl) is passed through a booster compressor (BC) which further vaporizes, pressurizes and heats the vaporized non-thermic fluid to provide further vaporized, pressurized and heated non-thermic fluid which heats up the lean capture media stream emerging from the desorber (D).
• the booster compressor (BC) receives the resultant vaporized non- thermic fluid and compresses the same to a pressure such that the condensation temperature of the non-thermic fluid is higher than the regeneration temperature.
• the booster compressor provides the resultant compressed non-thermic fluid to the third heat exchanger (Hex-C) from where it further moves to the fifth heat exchanger (Hex- A).
• the heated non-thermic fluid emerging from the third heat exchanger (Hex-C) is made to pass through a valve (V) before entering the fifth heat exchanger (Hex-A).
• This, in totality, is the non-thermic fluid cycle which aids in maintaining the regeneration temperature in the desorber (D).
• the thermic fluid emerging from the sixth heat exchanger (Hex-F) is cooled in a seventh heat exchanger (Hex-G) before entering the first heat exchanger (Hex-B).
• the capture media in the desorber (D) upon gaining regeneration temperature drives off a pre-determined quantity of water.
• This pre-determined quantity of water is characteristic of the amount of water present in the capture media.
• This pre-determined quantity of water is passed through and heated in the third heat exchanger (Hex-C), to provide steam.
• the generated steam is recycled back to the desorber (D) to aid the desorption process.
• a portion of the lean, hot capture media emerging from the desorber (D) is directed to the second heat exchanger (Hex-E), where it heats the incoming rich capture media stream.
• the resultant lean, warm capture media stream is then directed to the fourth heat exchanger (Hex-D) where it is cooled by an external source of water (C/W) to provide a cool lean capture media stream that is recycled to the absorber (A) for reiteration of the process.
• a make-up capture media solution is introduced into the absorber (A) along with the cool lean capture media stream in order to compensate for any further loss due to degradation.
• the lean, hot capture media emerging from the desorber (D) is made to pass through a third pump before being directed to the second heat exchanger (Hex-E).
• the invention of the present disclosure employs a heat pump concept for upgrading the heat quality of the non-thermic fluid.
• the heat pump concept involves cyclic evaporation, compression, condensation and expansion of the non-thermic fluid.
• the sources of low temperature process waste heat in oil refineries include, without limitation, refinery column overhead products where the streams are cooled using fin- fan coolers; while in power plants, the sources of low temperature process waste heat include thermal process streams or from other industrial process.
• any temperature level of process plant waste heat can be utilized for its usage in capture media regeneration, use of heat pumps for transferring heat energy from a heat source to a heat sink against a temperature gradient is preferred by using a relatively small amount of high quality drive energy such as electricity, fuel and high-temperature waste heat.
• the invention of the present disclosure employs a multi-compression cycle.
• the compression cycle in each stream loop like flue gas stream and the non-thermic fluid stream, provides necessary heat and its re-utilization for regeneration of capture media.
• the flue gas with/without excess quantity is compressed in a first compression cycle to generate the required quantity of heat that can be used within the capture process.
• the compression of the non-thermic fluid in the second compression cycle generates sufficient energy which finds its usage in regeneration of capture media and also within the process to compensate the heat demand.
• the present invention distinctly characterizes the method to compensate the shortfall in heat demand within the process by use, in combination, of recovery of low temperature process waste heat by the non-thermic fluid using the heat pump principle and recovery of flue gas heat by the thermic fluids.
• the low temperature process waste heat streams which are available in process plants cannot be used for steam generation.
• Sources of low temperature process waste heat in oil refinery may include without limitation particularly refinery column overhead products where the streams are cooled using fin-fan coolers, while in power plant may include thermal process streams or from other industrial process.
• a huge amount of heat which is wasted today can be reused for regeneration of the capture media in the process of carbon dioxide capture.
• the invention of the present disclosure offers several advantages over the conventional amine based absorption process, for all key performance parameters.
• the total heat required for regeneration of the capture media in the conventional amine based absorption process is higher than that required in the process of the present disclosure.
• the flue gas cooler in the present invention recovers maximum heat associated with the flue gas stream to utilize within the process.
• most of the heat is lost during cooling of the flue gas prior to absorption in the conventional amine process.
• the steam requirement significantly influences the operating cost associated with the regeneration of the capture media, but the present invention judiciously tackles the problem of heat demand for the regeneration step by utilizing the heat available with flue gas stream, which is an insignificant value as compared to the generation of steam.
• the quantity of the cooling water required in the present disclosure is appreciably lower than that required in the conventional amine based process.
• Example 1 The process of capture of C0 2 according to the present disclosure and its comparison with the conventional absorption process
• a stream of 62.5 (tonnes per hour) TPH of flue gas [carbon dioxide: 15, oxygen: 5 and nitrogen: rest, composition on the dry basis (vol %)] at 160 °C temperature and 1.013 bar pressure was introduced into a blower (B-1.2 MW) to obtain a 62.5 TPH flue gas stream at 225 °C temperature and 1.5 bar pressure.
• the pressurized flue gas stream was forwarded into a first heat exchanger (Hex-B) where the heat from the pressurized stream was extracted by circulating 38.4 TPH of Dowtherm as the thermic fluid at 35 °C, sourced from the seventh heat exchanger (Hex-G).
• the stream of the rich capture media at 59.2 °C and 1.25 bars was passed through a first pump (PI) and the resulting 1.8 bar rich capture media stream was directed to the second heat exchanger (Hex-E) for heating near its regeneration temperature by means of a 318.85 TPH of a lean, hot capture media stream at 115 °C, 2.5 bar pressure sourced from the third heat exchanger (Hex-C).
• Hex-E second heat exchanger
• 333.7 TPH of heated rich capture media at 105 °C resulted, which was further directed to a third separator (S3) where the generated C0 2 gas was separated from the rich capture media and then resultant 329.6 TPH of rich capture media at 105 °C was fed to the top of desorber (D) for complete regeneration.
• the vapor mixture from the third separator (S3) and the desorber (D) was fed to a second converger (Cv2) and the combined vapor stream from the second converger (Cv2) was passed through a condenser (Cd), where an external supply of cold water at 30 °C partially condensed the vapor stream.
• the two phase mixture of pure C0 2 gas and condensate were separated in the first separator (SI) and the condensate was refluxed back to the desorber (D).
• the lean capture media emerging from the desorber (D) was heated in the third heat exchanger (Hex-C) by means of 26 TPH of water vapor, as the non-thermic fluid, at 143 °C at 1.75 bar pressure.
• the steam emerging from the sixth heat exchanger (Hex-F) as well as the 23.45 TPH of steam from the second separator (S2) at 113.1 °C and 1.5 bar pressure was passed through a first converger (Cvl).
• 26 TPH of the converged steam emerging from the first converger (Cvl) at 112.6 °C and at 1.4 bar pressure was passed through a booster compressor (BC-0.41 MW) which further vaporized, pressurized and heated stream to provide 26 TPH of steam at 142.75 °C at 1.75 bar pressure.
• the steam was used for heating 346 TPH of the lean capture media emerging from the desorber (D) at 113.67 °C.
• the heated Dowtherm emerging from the sixth heat exchanger (Hex-F) was cooled in a seventh heat exchanger (Hex-G) before entering the first heat exchanger (Hex-B).
• 318.85 TPH of lean, hot capture media at 115 °C was further directed to the second heat exchanger (Hex-E), where it heated the incoming rich capture media at 59.22 °C.
• the resultant 318.85 TPH of lean, warm capture media at 62.95 °C was then directed to the fourth heat exchanger (Hex-D) where it was cooled by an external source of cold water at 30 °C to provide a 318.85 TPH of cool lean capture media at 40 °C that is recycled to the absorber (A) for reiteration of the process.
• a 1.75 TPH of make-up amine solution at 40 °C was introduced into the absorber (A) along with the cool lean capture media at 45 °C in order to compensate for any further loss due to degradation.
• the process and system of the present disclosure harness the heat associated with the flue gas along with the process waste heat and utilizes it to replenish the heat requirement within the process.
• the invention of the present disclosure also provides a heat integrated process that significantly reduces the operating cost by using a multiple-compression cycle for regeneration of the capture media used for carbon dioxide capture from flue gas stream.
• the process and system of the present disclosure can be easily retrofitted to existing facilities.

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• Chemical & Material Sciences (AREA)
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• Analytical Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Treating Waste Gases (AREA)
• Carbon And Carbon Compounds (AREA)
• Gas Separation By Absorption (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)

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• 2014
  • 2014-09-29 WO PCT/IN2014/000631 patent/WO2015052727A2/en active Application Filing
  • 2014-09-29 IN IN3192MU2013 patent/IN2013MU03192A/en unknown

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