Method for producing deacidified fluid stream, apparatus for deacidifying fluid stream, and use of heat pump for deacidifying fluid stream

Abstract

The present invention relates to a method for producing a deacidified fluid stream comprising heat pumps connected in series to transfer energy from a heat source to a regeneration step. In a second aspect, the invention relates to an apparatus for producing a stream of deacidified fluid, the apparatus comprising heat pumps connected in series. In a third aspect, the invention relates to the use of two heat pumps connected in series for transferring thermal energy from a heat source to a regeneration step in a process for deacidifying a fluid stream.

Description

[0001] The present invention relates to a method for producing a deacidified fluid flow, the method comprising heat pumps connected in series to transfer energy from a heat source to a regeneration step.

[0002] In a second aspect, the present invention relates to an apparatus for producing a deacidified fluid flow, the apparatus comprising heat pumps connected in series.

[0003] In a third aspect, the present invention relates to the use of two heat pumps connected in series for transferring thermal energy from a heat source to a regeneration step in a method for deacidifying a fluid flow.

[0004] Given the growing signs of impending climate change and its severe impact on the global population, the United Nations Sustainable Development Goals (SDGs) have identified "climate action" as one of the 17 SDGs. One of these 17 goals is to integrate climate change measures into national policies, strategies, and plans. The European Union has already implemented a comprehensive set of climate change policy initiatives with the goal of achieving climate neutrality by 2050. A more direct effect is the increase in greenhouse gas emission reduction targets to approximately 50% compared to 1990 levels, with the aim of achieving net-zero greenhouse gas emissions by 2050. Other governments around the world have adopted similar initiatives and incentives for climate protection.

[0005] Carbon dioxide is one of the most abundant greenhouse gases in the atmosphere. Greenhouse gases are gases that absorb and emit infrared radiation in a range of wavelengths emitted by the Earth, thus contributing to global warming. Atmospheric CO2 levels have increased from approximately 280 ppm in the pre-industrial era around 1750 to approximately 421 ppm in 2022. About two-thirds of all carbon dioxide emissions originate from the burning of fossil fuels.

[0006] Most climate action measures require huge financial investments and take years or even decades to implement.

[0007] Carbon capture and storage (CCS) or carbon capture, utilization and storage (CCUS) are readily available and developed technologies that can be implemented on a large scale within a short timeframe and therefore have a more direct impact on climate change. Carbon dioxide can be captured directly from industrial sources such as cement production, natural gas processing, and ammonia and hydrogen production, or from fossil or biomass fuel-powered power plants. Currently, carbon capture rates of 80% to 95% can be achieved from flue gas from carbon-based fuels.

[0008] Captured carbon dioxide can be removed from the atmosphere through carbon sequestration or storage in suitable geological formations such as depleted oil and gas reservoirs, mines, and salt or other rock formations. Before being transported to its final storage site and injected underground, the carbon dioxide is typically compressed to a high pressure of approximately 100 bar. Other uses of captured carbon dioxide include enhancing oil recovery or converting it into fuels, cement, minerals, or chemicals.

[0009] Currently, amine gas treatment is one of the most mature methods for carbon capture. Amine gas treatment refers to a process in which acidic gases (acid gases), such as carbon dioxide or hydrogen sulfide, are removed from the feed gas stream by absorption in an amine solvent. A typical acid gas removal unit (AGRU) includes an absorber, a regenerator, and auxiliary equipment. In the absorber, downward-flowing amine absorbs the acidic components of the feed gas to obtain a sweetened gas or sweet gas stream and an amine solution partially loaded with the acidic components (“rich amine”). The rich amine solution is then fed to a regenerator or stripper, where it is heated to strip or flash-desorb the desorbed acidic gas to the top and produce a regenerated amine solution (“lean amine”), which can be recycled back to the absorber. The stripped CO2 is then compressed, dried, and optionally refrigerated and transported to its storage destination.

[0010] Amine gas treatment is a relatively energy-intensive process. It is estimated that up to 40% of the energy generated by power plants is consumed in carbon capture and storage. This energy loss accounts for approximately 60% of the amine gas treatment process and 30% of the carbon dioxide compression. The energy-intensive portion of amine gas treatment is the stripping of captured carbon dioxide in the stripping tower. Temperatures in the absorber are typically between approximately 30°C and 70°C, while the temperatures required for carbon dioxide stripping are typically in the range of 100°C to 150°C. The energy required to heat the rich amine is usually supplied by transferring heat from the hot process steam to the rich amine in the regenerator.

[0011] Process steam can be generated in combined cycle gas-fired power plants. In such cases, steam production from electricity generation can be integrated into the amine gas handling process. However, for all AGRUs, steam integration with existing steam sources is not always possible, and the required steam then needs to be provided through a separate process steam production process, such as a steam boiler.

[0012] Therefore, many activities have addressed the need to reduce the energy consumption of amine gas processing units.

[0013] One possible strategy to reduce energy consumption is to try to improve the recycling capacity of amine solvents and reduce the energy required to regenerate them. However, solvent development is quite expensive and time-consuming, and often requires the use of specialized, high-cost solvent systems, leading to higher operating costs.

[0014] Another strategy for reducing energy consumption in amine gas processing units is to transfer heat from a source with a higher temperature within the gas processing unit to a location with a lower temperature.

[0015] The most prominent example of this heat transfer measure is the so-called cross-flow heat exchanger between the regenerator and the absorber, where hot, lean amine leaving the regenerator heats the cold, rich amine from the absorber before the rich amine is fed into the regenerator. However, the indirect heat exchange via the cross-flow heat exchanger is generally insufficient to supply most of the energy required to operate the stripping tower.

[0016] US 3823222 teaches the use of the energy contained in the hot feed gas to be deacidified in the AGRU to generate steam in a separate boiler, which can be used for steam stripping in the regenerator to heat the reboiler of the regenerator.

[0017] US 3101996 also teaches the use of hot fluid flows such as syngas or hydrogen obtained in a water shift reaction to generate steam in a separate boiler, which can be used to heat an amine stripping tower.

[0018] WO 200712143 discloses two separate cooling stages for cooling hot flue gas from a steam turbine prior to amine gas processing. In the initial stage, the flue gas is cooled in a heat exchanger by indirect heat exchange with a fluid used to heat the stripper tower. In the second stage, the flue gas is cooled by transferring heat energy to a heat pump system used to heat the stripper tower. The heat pump system can be supplemented by heat regenerated from other heat sources such as a CO2 compression stage.

[0019] Using heat pumps to transfer energy from processing units with higher thermal energy levels to those with lower thermal energy levels is not limited to hot feed gases. Many heat sources in amine gas processing have been suggested for use with heat pumps.

[0020] WO 2010097047 and WO 2011122525 utilize the absorbed heat in the absorber as the heat source for a heat pump to heat a rich amine solution.

[0021] JP 2015131735 uses the intercooler loop in the absorber as the heat source for the heat pump to heat the stripping tower.

[0022] WO 200781214 and CN 114405258 disclose the use of condensation energy generated in the condenser of a stripping tower as a heat source.

[0023] WO 201258558 describes the use of the thermal energy of stripping tower gas in the overhead condenser as a heat source for a heat pump. This disclosure is limited to the removal of SO2 from gaseous mixtures, but theoretically, this principle can be transferred to CO2 removal.

[0024] JP 2010088982 discloses the use of the heat of compression generated in one or more compressors used to compress carbon dioxide to high pressure for heating a rich amine solution.

[0025] JP 2015131736 essentially teaches the replacement of conventional cross-flow heat exchangers with heat pumps, which are used to transfer heat from the hot lean amine solution leaving the stripper to the rich amine solution entering the stripper.

[0026] FR 2968574 discloses multiple heat sources for heat pumps, such as the overhead condenser of a stripping column, the lean amine solution leaving the absorber, and the overhead condenser of the absorber, for the purpose of removing water vapor from sweetened gases.

[0027] Similarly, CN 10289584 mentions the use of lean amine solution leaving the stripper tower of the regenerator and the stripper tower top condenser as a heat source for a heat pump.

[0028] Heat sources other than those used in the amine gas treatment process can also be used.

[0029] CN 112126477 discloses the use of blast furnace slag washing water as a heat source for heating stripping towers with heat pumps.

[0030] The energy contained in the various heat sources disclosed is typically insufficient to provide all the energy required for the stripping step. Therefore, multiple heat sources need to be connected, necessitating the use of more than one heat pump. The use of several heat pumps increases the capital cost of the amine gas processing unit.

[0031] US 2013056676 relates to a polar oscillation-assisted regeneration (PSAR) method for improving the efficiency of releasing chemically bound gases into switchable ionic liquids (SWILs). SWIL regeneration involves adding a quantity of a nonpolar organic compound as an antisolvent to destabilize the SWIL, which facilitates the release of the chemically bound gases. Compared to heating in the absence of an antisolvent, PSAR reduces the gas load on the SWIL at a given temperature and increases the rate of gas release. In some embodiments, regeneration includes transferring heat using a heat pump to one or more of the following: a condenser, an evaporator, an absorber, a cooler, a separator, a regenerator, or a reboiler.

[0032] WO 2023 / 057372 relates to a gas capture system in which gas is captured by a liquid adsorbent. The adsorbent is recirculated between a first reactor system and a second reactor system. In the first reactor system, the adsorbent captures gas in a gas stream during an exothermic process. In the second reactor system, the adsorbent is regenerated and the captured gas is released during an endothermic process. The second gas capture system can operate at a lower pressure than the first gas capture system. Further disclosed is that various different configurations of heat pumps can be integrated within the gas capture system as an efficient means of electrifying the system.

[0033] Despite a significant amount of disclosure focusing on thermal integration in gas processing, there is still a need for a thermal integration solution that can supply most or all of the energy required in regenerators without causing a sharp increase in capital costs.

[0034] Therefore, a potential problem of the present invention is to provide a method for reducing the energy requirements of gas treatment units using liquid absorbents while reasonably limiting additional investment in plant infrastructure. Another potential problem of the present invention is to reduce corrosion and scaling in equipment in contact with fluid flows. Yet another potential problem of the present invention is to avoid the need for expensive equipment required for transporting gaseous flows. Additionally, an object of the present invention is to electrify the steam production required for the regeneration of the absorbent-rich solution, and potentially to separate steam production from electricity production in a power plant or the need for a separate steam production facility. A further object of the present invention is to reduce the energy requirements for steam production in the regeneration step. Yet another object of the present invention is to provide a flexible method that allows for capacity fluctuations in the AGRU.

[0035] 1st aspect - Method for producing a de-acidified fluid stream by a heat transfer process comprising two or more heat pumps Heat source

[0036] In a first aspect, the present invention relates to a method for producing a deacidification fluid stream comprising at least one acidic gas, the method comprising:

[0037] a) A heat transfer step, wherein heat energy is transferred from heat flow HS1 to a regeneration step c) to obtain a heat flow HS2 with reduced heat energy compared to heat flow HS1;

[0038] b) An absorption step in which fluid flow FS2 is contacted with absorbent A1 in an absorber to obtain absorbent A2 loaded with acidic gas and a fluid flow that is at least partially deacidified.

[0039] c) A regeneration step, wherein at least a portion of the loaded absorbent A2 obtained from step b) is regenerated in a regenerator to obtain at least partially regenerated absorbent A3 and a gaseous stream GS containing at least one acidic gas.

[0040] d) A recycling step, wherein at least one sub-stream of the regenerated absorbent A3 from step c) is recycled to the absorption step b);

[0041] The heat transfer step a) includes two or more heat pumps connected in series.

[0042] Fluid stream FS1

[0043] The method of the present invention includes transferring thermal energy from heat flow HS1 to regeneration step c) to obtain heat flow HS2 with reduced thermal energy compared to flow HS1.

[0044] The heat flow HS1 is preferably generated by the heat source HS.

[0045] The heat source HS can be any heat source from the gas handling process or an external heat source outside the gas handling process.

[0046] The heat source HS can be the absorbed heat generated in the absorber, which can be utilized in the intercooler or by integrating a heat exchanger into the absorber. In this case, flow HS1 is the hot flow leaving the absorber and flow HS2 is the cooling flow entering the absorber.

[0047] If the rewash zone is equipped with a pump and a cooler, another heat source HS is the absorbed heat in the rewash zone at the top of the absorber. In this case, flow HS1 is the hot flow leaving the rewash zone of the regenerator and flow HS2 is the cooling flow entering the regenerator.

[0048] Another heat source HS is the condensation heat of the condensate at the head of the absorber or regenerator. In this case, flow HS1 is the warm cooling medium flow leaving the condenser or backwash zone with a cooling pump around the head of the absorber or regenerator, and flow HS2 is the cooling medium flow entering the device for cooling.

[0049] Another heat source HS is the heat of compression during the compression step, which is generated when the gaseous stream GS is compressed, as described further below. In this case, stream HS1 is the compressed stream GS and stream HS2 is the cooled compressed stream GS.

[0050] https: / /

[0051] In a preferred embodiment of the present invention, flow HS1 is fluid flow FS1.

[0052] The fluid flow FS1 that transfers heat energy from it to the regeneration step c) can be any fluid flow containing at least one acidic gas.

[0053] Preferably, the fluid stream FS1 contains CO2. In addition to CO2, other acidic gases such as H2S, CS2, or COS may also be present. Additionally, sulfur and nitrogen oxides SO2 may also be present. x and NO x .

[0054] The content of acidic gas in fluid flow FS1 is typically 0.01% to 40% by volume, preferably 2% to 30% by volume, and more preferably 3% to 25% by volume.

[0055] The fluid flow FS1 in the method of this invention may contain water. The water content in the fluid flow is typically in the range of >0% by volume up to the content corresponding to the saturation concentration of water in the fluid flow under existing pressure and temperature conditions.

[0056] The temperature of the fluid flow FS1 is preferably in the range of 40°C to 300°C, more preferably 50°C to 250°C, and most preferably 60°C to 200°C. The method according to the invention is particularly suitable for flue gas with low temperatures in the range of 60°C to 250°C, because the thermal energy contained in such low-temperature fluid gas flow FS1 can be transferred to the energy level required in regeneration step c) by a combination of two or more heat pumps in series.

[0057] The pressure of fluid flow FS1 typically depends on the source of fluid flow FS1, as further outlined below.

[0058] Preferably, fluid flow 1 is flue gas.

[0059] Flue gas is preferably obtained by burning carbon-based fuels, such as fossil fuels like coal, natural gas and oil, or biomass feedstocks from plants, algae or animals.

[0060] Such combustion processes can occur in power plants or power stations. Preferably, the source of flue gas is coal, natural gas, petroleum, biofuels such as bioethanol or biodiesel, or biomass from forestry, agriculture, or aquaculture.

[0061] Preferably, the fluid flow FS1 is the flue gas leaving the steam turbine of the steam power plant, in which the generator is driven by steam obtained from the combustion of carbon-based fuel.

[0062] Most preferably, the fluid flow FS1 is the flue gas leaving the steam turbine of the gas-fired power plant, which is designed as a simple cycle gas turbine or a combined cycle power plant.

[0063] Prior to the method used in this invention, the flue gas flow FS1 may optionally be treated to remove particulate matter by filtration or electrostatic precipitation.

[0064] In a preferred embodiment, the flue gas flow FS1 is desulfurized by removing sulfur dioxide. An overview of flue gas desulfurization methods can be found in the Wikipedia article "Flue-gas desulfurization" (…). en.wikipedia.org / wiki / Flue-gas_desulfurization Step a) heat energy transfer from FS1 to regeneration step c) ) was found.

[0065] Flue gas flow FS1 preferably includes:

[0066] CO2: 1 vol.% to 25 vol.% (preferably 5 vol.% to 20 vol.%)

[0067] H2O: 3 vol.-% to 50 vol.-%, preferably 5 vol.-% to 30 vol.-%; and

[0068] O2: 0.1 vol.-% to 16 vol.-%, preferably 1 vol.-% to 10 vol.-%.

[0069] Additionally, even after the flue gas desulfurization step, the flue gas still contains small amounts of other gases, particularly nitrogen oxides (NOx). x ) and sulfur oxides (SO x ).

[0070] The flue gas also contains a certain amount of nitrogen, such that the sum of the volume fractions of each component present in the flue gas is 1 (or 100 vol.-%). Typically, the nitrogen content ranges from 40 vol.-% to 95 vol.-%.

[0071] Fluid flow FS1 is preferably in a gaseous state. Depending on the temperature and water content, fluid flow FS1 may also contain condensed water and acid.

[0072] When the fluid flow is flue gas, the pressure of the fluid flow FS1 entering the cooling step is typically at atmospheric pressure, preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1.3 bar, and even more preferably 0.9 to 1.2 bar.

[0073] The temperature of the fluid flue gas flow FS1 is preferably in the range of 50°C to 300°C, more preferably 60°C to 250°C, and most preferably 60°C to 200°C.

[0074] Fluid flow FS1 can also be an exhaust gas flow, where CO2 is emitted from industrial processes that release CO2 from chemical reactions. Such industrial process flows include CO2 emissions from the thermal decomposition of limestone and dolomite in cement production, CO2 emissions from the use of carbon as a reducing agent in the commercial production of metals from ores (e.g., iron production in blast furnaces), or CO2 emissions from biomass fermentation (e.g., converting sugar into alcohol).

[0075] In a preferred embodiment, the fluid flow FS1 is a flow that combines flue gas from a carbon fuel combustion process with CO2 emissions from industrial processes that generate CO2, such as cement production, metal production, or fermentation processes.

[0076] In a further preferred embodiment, fluid stream FS1 is a flue gas stream from the furnace of a pyrolysis furnace, wherein hydrocarbons (such as petroleum fractions, naphtha, and natural gas liquids such as methane, ethane, and propane) are thermally or catalytically cracked to obtain shorter-chain molecules or recombinant molecules with different structures. Preferably, fluid stream FS1 is flue gas from a steam cracking furnace.

[0077] Fluid flow FS1 can alternatively be crude syngas. This syngas (or "syngas") can be obtained from the gasification of coal or mineral oil, steam reforming of mineral oil distillates, steam reforming of methane, or automatic thermal reforming of natural gas. Syngas typically contains hydrogen, carbon monoxide, and some carbon dioxide and water.

[0078] The preferred fluid stream FS1 is the fluid stream exiting the water shift reactor during the production of syngas. The water shift reaction is preferably carried out as a high-temperature shift conversion (HTSC) at a temperature of about 300°C to 450°C, as a medium-temperature shift conversion (MTSC) at a temperature of about 150°C to 350°C, as a low-temperature shift conversion (LTSC) at a temperature of about 150°C to 250°C, or as an acid gas shift conversion (SGS) at a temperature of about 200°C to 300°C.

[0079] When the fluid flow is a synthesis gas, the total pressure is typically in the range of 5 to 120 bar, preferably 10 to 100 bar, and more preferably 10 to 60 bar.

[0080] Heat pump

[0081] Step 1) heat transfer from heat stream HS1 to heat pump 1

[0082] The method of the present invention includes a heat transfer step a), wherein heat energy is transferred from heat flow HS1 to a regeneration step c) to obtain a heat flow HS2 having reduced heat energy compared to heat flow HS1.

[0083] The heat transfer step a) includes at least two (or two or more) heat pumps connected in series.

[0084] A heat pump can be an open-loop heat pump or a closed-loop heat pump.

[0085] In a closed-loop heat pump, the working medium or heat transfer medium is essentially contained within the closed loop, meaning that the working medium or heat transfer medium is essentially in a steady state and does not come into contact with an external radiator or external source. In a heat pump with an open loop, the working medium or heat transfer medium is essentially not contained within the closed loop.

[0086] Within the scope of this invention, a heat pump is a device for transferring heat from a heat source at one temperature to a radiator at a higher temperature. An open-loop heat pump typically includes the following steps:

[0087] - Heat energy is typically transferred from a heat source to a heat transfer material using a heat exchanger, which is usually designed as an evaporator for at least a portion of the heat transfer material in a heat pump.

[0088] - In one or more compression steps, typically involving one or more compressors, partially vaporized heat transfer material is compressed to raise the temperature of the heat transfer material, and

[0089] - Typically, heat energy is transferred from the compressed heat transfer material to the radiator by means of another heat exchanger, which serves as a condenser for at least part of the gaseous heat transfer material of the heat pump.

[0090] The advantage of open-loop heat pumps is that they can utilize media from a variety of sources, especially water, which is often present in amine gas processing.

[0091] A closed-loop heat pump typically includes a heat transfer medium between the heat source and the radiator in a closed loop. This is usually implemented through an additional recirculation step of the heat transfer medium, such as recirculation step R1 or R2 for heat pump HP1 or HP2, as further described below.

[0092] Within the meaning of this invention, the need to use two heat pumps connected in series means that the compressed heat transfer medium of heat pump HP1 acts as the heat source for the heat transfer medium flow of heat pump HP2, which acts as a radiator for heat pump HP1, and heat energy is transferred from the heat transfer medium flow HTMS of heat pump HP1 to the heat transfer medium flow of heat pump HP2 through a shared heat exchanger HE2. In other words, heat exchanger HE2 serves as a condenser for the heat transfer material of heat pump HP1 and an evaporator for the heat transfer material of heat pump HP2.

[0093] The advantage of using two heat pumps connected in series is that the thermal energy from the heat flow HS1 can be increased to a level that can generate steam in heat pump HP2, which can then be used to transfer heat to regeneration step c). Therefore, the flow generated in heat pump HP2 can effectively replace the process steam typically required as the heat source in regeneration step c). Thus, using two heat pumps in series can replace the need for a separate process steam production process installed on-site at the sour gas removal unit or for steam turbines such as back-pressure turbines or exhaust condenser turbines that generate process steam to be decarbonized at the power plant. Therefore, the present invention is particularly useful where process steam is not readily available at the sour gas removal unit site. Moreover, where process steam is readily available at the site, the method according to the invention can be used as an alternative to producing process steam, thereby allowing potentially limited process steam resources to be used for other purposes or allowing for a reduction in power plant power losses associated with process steam production. Additionally, the method of the present invention is an interesting alternative in the design of new power plants combined with sour gas removal units for carbon capture, as it reduces the need to divert energy used for steam production to power the recycle step. In addition, the method of the present invention is a useful way to electrify steam production, so that the steam required in the amine gas treatment process can be provided by “green” electricity from renewable resources.

[0094] In a preferred embodiment, at least one, but preferably two, heat pumps include a step of expanding the compressed heat transfer medium flow after transferring heat energy to the radiator. These recycling steps R1 or R2 (described below) allow the heat transfer material to be recycled back to transfer step a), resulting in further improvements in the efficiency of the method because the need for replenishing heat transfer material is significantly reduced. This method is particularly advantageous when using heat transfer materials that have adverse environmental impacts, in which case it is preferable to include these materials in a closed loop.

[0095] In a further preferred embodiment, at least one, preferably the last, of the series-connected heat pumps operates as an open-loop heat pump, especially when the heat transfer material (HTM) used in the last heat pump is water. This alternative requires relatively lower capital costs. Open-loop heat pumps are simpler and less expensive to operate and maintain due to fewer components.

[0096] The heat transfer from heat flow HS1 to heat transfer material flow HTMS1 of the first heat pump HP1 can occur directly by exchanging thermal energy from heat flow HS1 to heat transfer material flow HTMS1 in heat exchanger HE1.

[0097] In a preferred embodiment, heat transfer from heat flow HS1 to heat transfer material flow HTMS1 of the first heat pump HP1 can occur indirectly via an intermediate cooling step. In the intermediate cooling step, heat energy from heat flow HS1 is transferred to cooling medium flow CMS1 to obtain a cooled heat flow HS2 and a cooling medium flow CMS2 with increased heat energy compared to cooling medium flow CMS1. Heat energy is then further transferred from cooling medium flow CMS2 to heat transfer material flow HTMS1 of the first heat pump HP1. Heat transfer in the self-cooling step is typically influenced by an additional heat exchanger HE-C, which is preferably a gas-liquid heat exchanger when heat flow HS1 is a fluid flow FS1. Heat transfer via the additional cooling step allows for the possibility of using a direct contact cooler (DCC) as the heat exchanger to directly transfer heat energy to cooling medium flow CMS1. Direct contact means that the flows are not separated by a separator, but rather in direct physical contact with each other (direct heat exchange).

[0098] Direct heat exchange is the opposite of indirect heat transfer, in which the heat flow HS1 and the cooling medium flow CMS1 do not come into direct contact, and heat exchange occurs indirectly through a partition wall or by transiently entering and leaving the wall (indirect heat exchange). The advantage of direct heat exchange is the increased exchange area between the two flows HS1 and CMS1, which reduces thermal resistance and maximizes thermal efficiency. Additionally, due to the high heat transfer rate per volume and because fouling and corrosion are generally not problems, direct heat exchangers typically have lower operating and capital costs than indirect heat exchangers. Furthermore, expensive equipment such as blowers or fans required to transport fluid flows like FS1 and FS2 in direct heat exchangers is generally unnecessary compared to indirect gas-liquid heat exchangers, because the pressure drop in direct heat exchangers is lower compared to indirect heat exchangers.

[0099] In a preferred embodiment of the present invention, the heat transfer step a) occurs directly from the heat flow HS1 and the heat transfer material HTM1 of the heat pump 1, and preferably includes the following steps:

[0100] 1) In the heat exchanger HE-1 of the first heat pump HP1, heat energy is transferred from heat flow HS1 to heat transfer medium flow HTMS1 of heat transfer material HTM1 to obtain heat transfer medium flow HTMS2 with increased heat energy compared with heat transfer medium flow HTMS1.

[0101] 2) Compress the heat transfer medium flow HTMS2 in the first heat pump HP1 to obtain a heat transfer medium flow HTMS3 with a higher pressure than the heat transfer medium flow HTMS2.

[0102] 3) In the heat exchanger HE-2 of the second heat pump HP2, heat energy is transferred from the heat transfer medium flow HTMS3 of the first heat pump HP1 to the second heat transfer medium flow SHTMS1 of the second heat transfer material HTM2, so as to obtain a second heat transfer medium flow SHTMS2 with increased heat energy compared with the second heat transfer medium flow SHTMS1 and a heat transfer medium flow HTMS4 with reduced heat energy content compared with the heat transfer medium flow HTMS3.

[0103] 4) Compress the second heat transfer medium flow SHTMS2 in the second heat pump HP2 to obtain a second heat transfer medium flow SHTMS3 with a higher pressure than the second heat transfer medium flow SHTMS2.

[0104] 5) Transfer heat energy from the second heat transfer medium flow SHTMS3 of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium flow SHTMS4 with a reduced heat energy content compared to SHTMS3.

[0105] In a further preferred embodiment, step 1) of the method according to the invention is performed indirectly via an intermediate cooling step and includes the following steps:

[0106] 1a) Transfer heat energy from FS1 to cooling medium flow CMS1 to obtain a) a fluid flow FS2 with a lower heat energy content compared to FS1, and b) a cooling medium flow CMS2 with an increased heat energy content compared to CMS1;

[0107] 1b) Transfer at least a portion of the thermal energy contained in the cooling medium CMS2 to the heat transfer medium flow HTMS1, thereby obtaining a heat transfer medium flow HTMS2 with increased thermal energy compared to HTMS1 and a cooling medium flow with reduced thermal energy compared to CMS2 and at least partially recycled to step 1a) as CMS1.

[0108] In a further preferred embodiment, the method of the present invention further includes one of the following two recycling steps:

[0109] R1) expands the heat transfer material flow HTMS4 obtained in step 3) to obtain a reduced pressure compared to the heat transfer material flow HTMS4 and is at least partially recycled as heat transfer material flow HTMS1 to the heat transfer medium flow HTMS5 in step 1).

[0110] R2) Expand the second heat transfer material flow SHTMS4 obtained in step 5) to obtain a reduced pressure compared to the second heat transfer material flow SHTMS4 and at least partially recycle it as the second heat transfer material flow SHTMS1 to the second heat transfer medium flow SHTMS5 in step 3).

[0111] Heat transfer material HTM1

[0112] In step 1) of the preferred embodiment of the present invention, thermal energy is transferred from heat flow HS1 to heat transfer medium flow HTMS1 of the first heat pump HP1 to obtain heat transfer medium flow HTMS2 with increased thermal energy compared to heat transfer medium flow HTMS1. Furthermore, a cooled heat flow HS2 with lower thermal energy compared to heat flow HS1 is obtained.

[0113] As explained above, a heat pump HP1 is a device suitable for transferring heat energy from a heat flow HS1, which serves as a heat source, to a heat transfer medium flow HTMS1 within the heat pump HP1. As explained above, a heat pump HP1 can be an open-loop heat pump or a closed-loop heat pump.

[0114] The heat pump HP1 preferably includes:

[0115] - Heat exchanger HE1, which is used to transfer heat energy from heat source HS1 to heat pump HP heat transfer medium flow HTMS1, to obtain heat transfer material flow HTMS2 with increased heat energy compared to heat transfer medium flow HTMS1.

[0116] - One or more compressors, wherein the one or more compressors are used to compress the heat transfer material stream HTMS2 in one or more compression steps to obtain a heat transfer material stream HTMS3 having an increased pressure compared to the heat transfer material stream HTMS2.

[0117] - Heat exchanger HE2, which is used to transfer heat energy from the heat transfer material flow HTMS3 of the first heat pump to the second heat transfer material flow SHTMS1 of the second heat pump HP2, to obtain a heat transfer material flow HTMS4 of the first heat pump HP1 with reduced heat energy compared to the heat transfer material flow HTMS3, and

[0118] Additionally, if HP1 is a closed-loop heat pump, then HP1 preferably includes:

[0119] - One or more expansion devices are used to expand the heat transfer material flow HTMS4 to obtain a heat transfer material flow HTMS5 with a reduced pressure compared to the heat transfer material flow HTMS4.

[0120] Direct heat transfer from HS1 to HTMS1 by heat exchanger HE1

[0121] The heat transfer material HTM1 is the working fluid in heat pump HP1 used to transport heat energy from heat exchanger HE1 to heat exchanger HE2.

[0122] Preferably, the heat transfer material HTM1 can undergo at least a partial phase change from liquid to gaseous when transferring heat energy in the heat exchanger HE1.

[0123] Preferably, the heat transfer material HTM1 can also undergo at least a partial phase change from gaseous to liquid when the heat energy in the heat exchanger HE2 is transferred to the second heat pump HP2.

[0124] Therefore, the heat transfer material HTM1 is preferably selected from the group of refrigerants consisting of: ammonia, butane, R1233zd(e), R1224yd(z), air, CO2, water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, hydrocarbons, perfluorinated (2-methyl-3-pentanone) and mixtures thereof. Suitable refrigerants are known to those skilled in the art and disclosed, for example, in C. Arpagaus et al. (C. Arpagaus et al., Energy 152 (2018), pp. 985-1010).

[0125] Heat transfer material flows 1 to 5 are the flows of heat transfer material 1 in different stages of heat pump HP1, wherein:

[0126] -The heat transfer material flow HTMS1 is the flow of heat transfer material HTM1 entering step 1);

[0127] - The heat transfer material flow HTMS2 is the flow of heat transfer material HTM1 that leaves step 1) and enters compression step 2);

[0128] - The heat transfer material flow HTMS3 is the flow of heat transfer material HTM1 that leaves the compression step 2) and enters the step 3);

[0129] - The heat transfer material flow HTMS4 is the flow of heat transfer material HTM1 that leaves step 3) and may optionally enter the recirculation step R1);

[0130] - The heat transfer material flow HTMS5 is the flow of heat transfer material HTM1 leaving the recirculation step R1).

[0131] https: / / doi.org / 10.1002 / 14356007.b03_02.pub2

[0132] In step 1) of the present invention, 1) the heat energy from the heat flow HS1 is transferred to the heat transfer medium flow HTMS1 of the first heat pump HP1 to obtain a heat transfer medium flow HTMS2 with increased heat energy compared to the heat transfer medium flow HTMS1, and a cooled heat flow HS2 with lower heat energy compared to the heat flow HS1.

[0133] In a preferred embodiment of the present invention, the thermal energy of heat flow HS1 is directly transferred to the heat transfer material flow HTMS1 of heat pump HP1.

[0134] The transfer of heat energy from heat flow HS1 to heat transfer material flow HTMS1 is usually achieved through heat exchanger HE1.

[0135] The heat exchanger HE1 is typically a device used to transfer thermal energy in the form of heat between heat flow HS1 and heat transfer medium flow HTMS1 to obtain heat transfer medium flow HTMS2 with increased thermal energy compared to heat transfer medium HTMS1 and heat flow HS2 with reduced thermal energy compared to heat flow HS1.

[0136] In a preferred embodiment, the heat exchanger HE1 is an indirect heat exchanger, wherein the transfer of heat between the heat flow HS1 and the heat transfer medium flow HTMS1 occurs indirectly through a partition wall or transiently into and out of the wall, without any physical contact or material transfer between the two flows (indirect heat exchange).

[0137] When heat exchanger HE1 is an indirect heat exchanger, HE1 typically includes:

[0138] - The inlet of the heat flow HS1, at which the heat flow has a pressure p HS1 and temperature T HS1 ;

[0139] - The outlet of heat flow HS2, at which the heat flow has a pressure p HS2 and temperature T HS2 ;

[0140] - The inlet of the heat transfer medium HTMS1, at which the heat transfer medium has a pressure p HTMS1 and temperature T HTMS1 ;as well as

[0141] - The outlet of the heat transfer medium HTMS2, at which the heat transfer medium flows with pressure p HTMS2 and temperature T HTMS2 .

[0142] Preferably, the heat exchanger HE1 is an indirect gas-liquid heat exchanger, wherein heat is transferred between a gaseous heat flow HS1 and a liquid heat transfer material flow HTMS1.

[0143] Preferably, the gas-liquid heat exchanger is an extended surface heat exchanger, as described in Chapter 2.1.3 of the article "Heat Exchangers, 1. Fundamentals and General Design Methodology" in Ullmann's Encyclopedia of Industrial Chemistry. https: / / en.wikipedia.org / wiki / Cooling_More preferably, a plate-fin heat exchanger, such as the plate-fin heat exchanger described in Chapter 2.1.3.1 of the same reference, or a tube-fin heat exchanger, such as the tube-fin heat exchanger described in Chapter 2.1.3.2 of the same reference.

[0144] The heat exchanger HE1 is preferably designed in such a way that the following requirements are met:

[0145] -Temperature T HTMS1 Preferred ratio T FS1 The lower is 1 K to 100 K, more preferably 2 K to 60 K, and most preferably 5 K to 30 K.

[0146] -Temperature T FS2 Preferably, the temperature is in the range of 20°C to 80°C, more preferably 25°C to 70°C, and most preferably in the range of 30°C to 60°C.

[0147] - The heat transfer material flow HTMS1 undergoes at least a partial phase change from liquid to gas in the heat exchanger HE1.

[0148] Typically, a pressure drop occurs in indirect gas-liquid heat exchangers. To transport gaseous heat flow HS2, such as FS2, from heat exchanger HE1 to the absorber and to overcome the pressure drop in indirect heat exchanger HE1, it is recommended to use an additional blower or fan after the outlet of heat flow HS2.

[0149] In a preferred embodiment, the heat exchanger HE1 is designed such that it transfers more energy than is required in the regeneration step. In this case, the excess energy can preferably be used to provide excess steam, which can be diverted to the on-site steam network for distribution to other processes or process steps on-site that may require this energy.

[0150] Alternatively, the heat exchanger HE1 can be designed such that less energy is transferred than is required in the regeneration step. In this case, it is preferable to provide additional energy to the regeneration step from other sources, preferably steam, such as an on-site steam network distributing steam from other steam generation sources.

[0151] If the heat flow HS1 is a fluid flow FS1, then the heat exchanger HE1 is preferably designed such that the transferred heat energy is just sufficient to provide the heat energy required in regeneration step c). If the heat energy or heat contained in the heat flow FS1 is more than the heat energy or heat energy required to be transported to regeneration step c) by the heat pump, then only the energy required in regeneration step c) is transferred in the heat exchanger HE1. If the fluid flow FS2 will be too hot to enter the absorber after transferring the heat or heat energy required in regeneration step c), it is preferable to cool the fluid flow FS2 leaving the heat exchanger HE1 in one or more additional heat exchangers before entering the absorber, so that the fluid flow FS2 has a temperature at the inlet of the absorber in the range of 20°C to 80°C, more preferably 25°C to 70°C, and most preferably 30°C to 60°C.

[0152] Such additional heat exchangers are classic heat exchangers, such as plate heat exchangers, shell-and-tube heat exchangers, air coolers, or water coolers, such as cooling towers. An overview of cooling towers that can be used to further cool the fluid flow FS2 can be found in the Wikipedia article "Cooling towers" (…). tower# Indirect heat exchange from HS1 to HTMS1 via intermediate cooling step The advantage of this embodiment is that the temperature of the fluid flow FS2 at the absorber inlet can be adjusted independently of the operation of the heat pump HP1.

[0153] Step 1a) - transfer of heat energy via heat exchanger HE-C

[0154] In a preferred embodiment of the present invention, the heat transfer step 1) of transferring thermal energy from heat flow HS1 to heat transfer medium flow HTMS1 of the first heat pump HP1 to obtain heat transfer medium flow HTMS2 with increased thermal energy compared to heat transfer medium flow HTMS1 includes the following steps:

[0155] 1a) Transfer heat energy from heat flow HS1 to cooling medium flow CMS1 to obtain a) heat flow HS2 with a reduced heat energy content compared to heat flow HS1, and b) cooling medium flow CMS2 with an increased heat energy content compared to CMS1;

[0156] 1b) Transfer at least a portion of the thermal energy contained in the cooling medium CMS2 to the heat transfer medium flow HTMS1, thereby obtaining a heat transfer medium flow HTMS2 with increased thermal energy compared to HTMS1 and a cooling medium flow CMS3 with reduced thermal energy compared to CMS2 and recycled at least partially as CMS1 to the cooling medium flow CMS3 in step 1a).

[0157] HE-C = gas-liquid heat exchanger

[0158] In step 1a), the transfer of thermal energy from the heat flow HS1 to the cooling medium flow CMS1 is preferably achieved in the heat exchanger HE-C.

[0159] The preferred heat exchanger HE-C includes:

[0160] - The inlet of the heat flow HS1, at which the heat flow has a pressure p HS1 and temperature T HS1 ;

[0161] - The outlet of heat flow HS2, at which the heat flow has a pressure p HS2 and temperature T HS2 ;

[0162] - The inlet of the cooling medium flow CMS1, at which the cooling medium flow is at pressure p CMS1 and temperature T CMS1 Below; and

[0163] - The outlet of the cooling medium flow CMS2, at which the cooling medium flow has a pressure p CMS2 and temperature T CMS2 .

[0164] https: / /

[0165] In a preferred embodiment, if the heat flow HS1 is a gaseous flow such as FS1, then the heat exchanger HE-C is an indirect gas-liquid heat exchanger, wherein heat is transferred between the gaseous flow HS1 and the liquid cooling medium flow CMS1. Preferably, the gas-liquid heat exchanger is an extended surface heat exchanger, as described in Chapter 2.1.3 of the article "Heat Exchangers, 1. Fundamentals and General Design Methodology" in Ullmann's Encyclopedia of Industrial Chemistry. doi.org / 10.1002 / 14356007.b03_02.pub2 HE-C = direct heat exchanger More preferably, a plate-fin heat exchanger, such as the plate-fin heat exchanger described in Chapter 2.1.3.1 of the same reference, or a tube-fin heat exchanger, such as the tube-fin heat exchanger described in Chapter 2.1.3.2 of the same reference.

[0166] The heat exchanger HE-C is preferably designed in such a way that it meets the following requirements:

[0167] -Temperature T CMS1 Preferred ratio T FS1The lower is 1 K to 100 K, more preferably 2 K to 80 K, and most preferably 5 K to 50 K.

[0168] -Temperature T HS2 Preferably, the temperature is in the range of 20°C to 80°C, more preferably 25°C to 70°C, and most preferably in the range of 30°C to 60°C.

[0169] Typically, a pressure drop occurs in indirect gas-liquid heat exchangers. To transport gaseous heat flow HS2, such as FS2, from the heat exchanger HE-C to the absorber and to overcome the pressure drop in the indirect heat exchanger HE-C, it is recommended to use an additional blower or fan after the outlet of the gaseous heat flow HS2.

[0170] https: / / doi.org /

[0171] In a more preferred embodiment, when the heat flow HS1 is a gaseous flow, particularly when the heat flow HS1 is a fluid flow FS1, the heat exchanger HE-C is preferably a direct heat exchanger, wherein the heat flow HS1 is in direct contact with the cooling medium flow CMS1. Direct contact means that the flows are not separated by a separator, but are in direct physical contact with each other (direct heat exchange).

[0172] The advantage of direct heat exchange lies in the increased exchange area between the two fluid flows HS1 and CMS1, which reduces thermal resistance and maximizes thermal efficiency. Furthermore, due to the high heat transfer rate per volume and because scaling and corrosion are generally not problems, direct heat exchangers typically have lower operating and capital costs than indirect heat exchangers. Residual sulfur oxides (SO₄) are present in fluid flow FS1. x In the case of indirect heat exchangers, corrosion is a significant problem. If the temperature of any metal in contact with FS1 is below the dew point of sulfuric acid (typically in the range of 110°C to 170°C), residual sulfur oxides can cause dew point corrosion. Furthermore, the pressure loss in direct heat exchangers (HE-C) is lower than indirect gas-liquid heat exchangers. Therefore, the size of expensive equipment such as fans or blowers required to compensate for pressure losses and transport the fluid flow FS2 to the absorber can be reduced, or even avoided altogether.

[0173] Direct contact preferably occurs in a direct contact cooler (DCC), where heat is transferred from the fluid flow FS1 to the liquid cooling medium flow CMS1. Within this invention, the terms "direct contact condenser" and "direct contact cooler" are used synonymously because the degree of condensation occurring in the DCC depends on the water content of the feed gas.

[0174] Direct contact cooling can be achieved using the following devices: a) spray tower, b) baffle tower, c) sieve plate tower or bubble cap tower, d) packed tower, e) pipe contactor, and f) mechanical agitator contactor.

[0175] Further details regarding the design of direct-contact coolers can be found in the review article by Madejski et al. (Madejski, P.; Kus, T.; Michalak, P.; Karch, M.; Subramanian, N. DirectContact Condensers: A Comprehensive Review of Experimental and Numerical Investigations on Direct-Contact Condensation. Energies 2022, 15, 9312). 10.3390 / en15249312 https: / / en.wikipedia.org / wiki / Cooling_tower# (See Kreith, Frank & Boehm, Robert. (1987). Direct-Contact Heat Transfer. 10.1615 / AtoZ.d.DIRCONHEATRA, Chapter 19, pp. 1359-1399.)

[0176] Typically, direct contact coolers (DCCs) operate in counter-flow mode, meaning that the heat flow HS1 typically enters at an inlet opposite to the inlet of the cooling medium flow CMS1. However, DCCs can also operate in co-flow mode, where CMS1 and HS1 enter the heat exchanger from the same direction. Co-flow mode DCCs are described in US 9034081.

[0177] The most preferred direct contact coolers are spray towers, baffle towers, sieve plate towers, bubble cap towers, and packed towers. More preferably, the cooler operates in counter-current mode.

[0178] In DCC, the heat flow HS1 is in direct contact with the cooling medium flow CMS1, and heat energy is transferred from the heat flow HS1 to obtain the cooled heat flow HS2 and the heated cooling medium flow CMS2.

[0179] The cooling medium CMS1 is preferably ethylene glycol, 1,2-propanediol, 1,3-propanediol and their corresponding polyglycols, such as diethylene glycol, triethylene glycol, 1,2-dipropanediol, 1,2-tripropanediol, 1,3-dipropanediol and 1,3-tripropanediol, their corresponding dimethyl ether or dimethyl ether, water and mixtures thereof. Preferably, the cooling medium is ethylene glycol or water, or...

[0180] A mixture of ethylene glycol and water. Most preferably, the cooling medium stream consists primarily of water. The advantage of using pure water is that no additional separation step is required. When the cooling medium stream CMS1 contains components other than water, additional separation steps are preferred because the water contained in the heat stream HS1 causes dilution of the concentration of other non-aqueous components. To restore the original concentration, additional separation steps will be required to separate the water introduced with the heat stream HS1.

[0181] The direct contact cooler is preferably designed in such a way that the following requirements are met:

[0182] -Temperature T CMS1 The temperature ranges from 25°C to 100°C, preferably from 25°C to 70°C, and more preferably from 30°C to 50°C.

[0183] -Temperature T CMS2 T CMS1 The K content is approximately 5 K to 100 K, preferably 10 K to 80 K, and more preferably 15 K to 50 K.

[0184] -Temperature T HS2 Preferably, the temperature is in the range of 20°C to 80°C, more preferably 25°C to 70°C, and most preferably in the range of 30°C to 60°C.

[0185] DCC is also typically operated to keep the cooling medium flow CMS2 in a liquid state, so that it can be easily separated from the gaseous fluid flow FS2.

[0186] If additional moisture contained in the heat flow HS1 (especially if HS1 is fluid flow FS1) condenses in the DCC, a portion of the cooling medium flow CMS2 can be removed from the cooling medium flow circulation. The amount of cooling medium flow removed is chosen in such a way that the cooling medium flow rate remains substantially constant.

[0187] In a preferred embodiment, the heat exchanger HE-C is designed such that it transfers more energy than is required for the regeneration step. In this case, the excess energy can preferably be used to provide excess steam, which can be diverted to the on-site steam network for distribution to other processes or process steps on-site that may require this energy.

[0188] Alternatively, the heat exchanger HE-C can also be designed such that less energy is transferred than is required in the regeneration step. In this case, it is preferable to provide additional energy to the regeneration step from an additional source (e.g., an on-site steam network distributing steam from other steam generation sources), preferably steam.

[0189] If the heat flow HS1 is a fluid flow FS1, the heat exchanger HE-C is preferably designed such that the transferred heat energy is just sufficient to provide the heat energy required in regeneration step c). If the heat energy or heat contained in the heat flow FS1 is more than the heat energy or heat energy required to be transported to regeneration step c) by the heat pump, then only the energy required in regeneration step c) is transferred in the heat exchanger HE-C. If the fluid flow FS2 will be too hot to enter the absorber after transferring the heat or heat energy required in regeneration step c), it is preferable to cool the fluid flow FS2 leaving the heat exchanger HE-C in one or more additional heat exchangers before entering the absorber, such that the fluid flow FS2 has a temperature at the inlet of the absorber in the range of 20°C to 80°C, more preferably 25°C to 70°C, and most preferably 30°C to 60°C. Such additional heat exchangers are air coolers or water coolers, such as cooling towers. An overview of cooling towers that can be used to further cool the fluid flow FS2 can be found in the Wikipedia article "Cooling towers". Step 1b) transfer of heat energy from cooling medium stream CMS2 to heat pump HP1 The advantage of this embodiment is that the temperature of the fluid flow FS2 at the absorber inlet can be adjusted independently of the operation of the heat pump HP1.

[0190] Step 2) compression of HTMS2 to HTMS3

[0191] After transferring thermal energy from heat flow HS1 to cooling medium flow CMS1 and obtaining cooling medium flow CMS2 with higher thermal energy than cooling medium flow CMS1, step 1b) is preferably performed by transferring at least a portion of the thermal energy contained in cooling medium CMS2 to heat transfer medium flow HTMS1 of heat pump HP1, thereby obtaining heat transfer medium flow HTMS2 with increased thermal energy compared to HTMS1 and cooling medium flow CMS3 with reduced thermal energy compared to CMS2 and at least partially recycled as CMS1 to the cooling medium flow CMS3 of step 1a).

[0192] In step 1b), CMS2 serves as the heat source for heat pump HP1 and transfers heat energy from the cooling medium flow CMS2 to the heat transfer medium flow HTMS1. The heat energy transfer in step 1b) is preferably achieved through heat exchanger HE1, which is preferably an indirect heat exchanger.

[0193] In the case of indirect heat transfer via an intermediate cooling cycle, the heat exchanger HE-1 preferably comprises:

[0194] - The inlet of the cooling medium flow CMS2, at which the cooling medium flow has a pressure p CMS2 and temperature T CMS2 ;

[0195] - The outlet of the cooling medium flow CMS3, at which the cooling medium flow has a pressure p CMS3 and temperature T CMS3 ;

[0196] - The inlet of the heat transfer material flow HTMS1, at which the heat transfer material flow is under pressure p HTMS1 and temperature T HTMS1 Below; and

[0197] - The outlet of the heat transfer medium HTMS2, at which the heat transfer medium flows with pressure p HTMS2 and temperature T HTMS2 .

[0198] In cases where indirect heat transfer occurs via an intermediate cooling cycle, the heat exchanger HE1 is preferably an indirect heat exchanger, such as an evaporator. More particularly, HE1 is preferably a tubular heat exchanger, preferably a shell-and-tube heat exchanger, a double-tube heat exchanger, a drip-type heat exchanger, or a plate heat exchanger. Most preferably, the heat exchanger HE1 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0199] In the case of indirect heat transfer via an intermediate cooling cycle, the heat exchanger HE1 is preferably designed in such a way that the following requirements are met:

[0200] -Temperature T CMS2 The temperature ranges from 25°C to 120°C, preferably from 30°C to 100°C, and more preferably from 40°C to 70°C.

[0201] -Temperature T HTMS2 T HTMS1 The K content is approximately 0.1 K to 50 K, preferably 0.5 K to 25 K, and more preferably 1 K to 10 K.

[0202] - The heat transfer material HTM1 in the heat transfer material flow HTMS1 undergoes at least a partial phase change from liquid to gas.

[0203] The cooling medium flow CMS3 may need to undergo an additional cooling step 1c), which is preferably carried out in a heat exchanger HE-CMS, preferably a water or air cooler, to impart the same characteristics to the cooling medium flow CMS3 as to the cooling medium flow CMS1, so that the cooling medium flow CMS3 can be recycled as the cooling medium flow CMS1.

[0204] For both the direct heat transfer via step 1) and the indirect heat transfer via the intermediate cooling cycle, according to steps 1a) and 1b), heat energy is transferred to the heat transfer material flow HTMS1 to obtain a heat transfer flow HTMS2 with increased heat energy compared to the heat transfer medium flow HTMS1.

[0205] Therefore, the heat transfer material HTM1 is preferably selected from the materials listed above, so that the phase change can occur at the temperature and pressure commonly present in the heat exchanger HE1.

[0206] Step 3) heat transfer from HP1 to HP2

[0207] After the heat energy has been transferred to the heat transfer medium flow HTMS2, it is preferable to further transfer the heat energy in step 2) by compressing the heat transfer medium flow HTMS2 in the first heat pump HP1 to obtain a heat transfer medium flow HTMS3 with a higher pressure than the heat transfer medium flow HTMS2.

[0208] Compression is preferably achieved in a compressor.

[0209] A compressor is a device used to increase the pressure of at least a portion of a gaseous fluid.

[0210] Compressors are typically positive displacement compressors or dynamic compressors. Positive displacement compressors include reciprocating compressors, which use crankshaft-driven pistons to deliver fluids at higher pressures. Reciprocating compressors can be single-stage or multi-stage. Positive displacement compressors also include rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors, or scroll compressors.

[0211] The compressor can also be a dynamic compressor, such as a centrifugal compressor or an axial compressor.

[0212] Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a reciprocating compressor, or an axial flow compressor.

[0213] Compression can be carried out in one compressor or a series of compressors, depending on the desired pressure increase of the heat transfer material HTM1.

[0214] Heat transfer material HTM1 is used as a heat transfer material under pressure p HTMS2 and temperature T HTSM2 The heat transfer material flow HTMS2 enters the compression step and is under pressure p HTMS3 and temperature T HTMS3 The heat transfer material HTMS3 leaves the compression step.

[0215] Typically, the pressure increase Δp(p) in the compression step is chosen. HTMS3 -p HTMS2 This raises the temperature of the heat transfer medium flow to a level that can induce a liquid-gas phase change in the heat transfer material HTM2 of the second heat pump HP2. Preferably, the pressure is increased so that HTMS3, compared to the heat transfer material HTM2 in heat pump HP2, has a higher pressure than... SHTMS1The boiling temperature under pressure is 50 K or more, more preferably 80 K or more, and most preferably 100 K or more, to allow any heat loss to be compensated and to allow the heat transfer material HTM2 in the heat pump HP2 to evaporate completely.

[0216] Heat pump HP2

[0217] After increasing the pressure to obtain the heat transfer medium flow HTMS3, in step 3), the heat energy is further transferred from heat pump HP1 to heat pump HP2 by transferring the heat energy from the heat transfer medium flow HTMS3 of the first heat pump HP1 to the second heat pump HP2 heat transfer medium flow SHTMS1, so as to obtain the second heat transfer medium flow SHTMS2 with increased heat energy compared to the second heat transfer medium flow SHTMS1 and the heat transfer medium flow HTMS4 with reduced heat energy content compared to the heat transfer medium flow HTMS3.

[0218] Heat transfer material HTM2

[0219] The transfer of heat from the heat transfer material flow HTMS3 to the second heat transfer material flow HTMS1 is preferably achieved through the heat exchanger HE2.

[0220] Heat exchanger HE2 is a device for transferring thermal energy in the form of heat between heat transfer material flow HTMS3 and second heat transfer medium flow SHTMS1 to obtain a second heat transfer medium flow SHTMS2 with increased thermal energy compared to heat transfer medium SHTMS1 and a heat transfer material flow HTMS4 with decreased thermal energy compared to heat transfer material flow HTMS3.

[0221] The heat exchanger HE2 is preferably an indirect heat exchanger.

[0222] When the heat exchanger HE2 is an indirect heat exchanger, HE2 preferably includes:

[0223] - The inlet of the heat transfer medium HTMS3, at which the heat transfer medium has a pressure p HTMS3 and temperature T HTMS3 ;

[0224] - The outlet of the heat transfer medium HTMS3, at which the heat transfer medium flows with pressure p HTMS3 and temperature T HTMS3 ;

[0225] - The inlet of the second heat transfer medium flow SHTMS1, at which the second heat transfer medium flow has a pressure p SHTMS1 and temperature T SHTMS1 ;as well as

[0226] - The outlet of the second heat transfer medium flow SHTMS2, at which the second heat transfer medium flow has a pressure p SHTMS2 and temperature T SHTMS2 .

[0227] More preferably, the heat exchanger HE2 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0228] The heat exchanger HE2 is preferably designed in such a way that the following requirements are met:

[0229] -Temperature T HTMS3 Significantly higher than the boiling point of heat transfer material HTM2 in heat pump HP2 at regulated pressure, preferably higher than that of heat transfer material SHTM1 at pressure p SHTMS1 The boiling point is 5 K to 200 K or more, preferably 5 K to 50 K or more, and most preferably 5 K to 25 K or more.

[0230] -Temperature T SHTMS2 T SHTMS1 The concentration is approximately 0.1 K to 50 K, preferably 0.3 K to 15 K, and more preferably 1 K to 5 K.

[0231] - The second heat transfer material in the heat pump HP2, the heat transfer material HTM2 in SHTMS1, undergoes at least a partial phase change from liquid to gas.

[0232] - Pressure p SHTMS1 Preferably within the range of approximately 1 bar. The pressure p is possible. SHTMS1 Below atmospheric pressure, such as 0.1 to 1 bar, but in a preferred embodiment, the pressure p on the side of the second heat transfer material SHTM is... SHTMS1 The pressure is at or above atmospheric pressure, preferably in the range of 0.7 to 2 bar, more preferably 0.8 to 1.5 bar and even more preferably 0.9 to 1.2 bar.

[0233] Step 4) compression of SHTMS2 to SHTMS3

[0234] The heat transfer material HTM2 is the working fluid in the heat pump HP2 used to transfer heat energy from heat exchanger HE2 to heat exchanger HE-R.

[0235] Preferably, the heat transfer material HTM2 can undergo at least a partial phase change from liquid to gas when transferring heat energy in the heat exchanger HE2.

[0236] Preferably, the heat transfer material HTM2 can also undergo at least a partial phase change from gaseous to liquid state when transferring heat energy in the heat exchanger HE-R.

[0237] The heat transfer material HTM2 is preferably a substance that has the following properties in p SHTMS1 The boiling point is lower than that at pHTMS3 T below HTMS3 And it is below the operating temperature of the regenerator.

[0238] Therefore, besides water, under pressure p SHTMS1 Any other material with a boiling point below 150°C, preferably 140°C and more preferably below 130°C is preferred.

[0239] The preferred heat transfer material HTM2 is water, because water can undergo at least part of the vapor phase change in the heat exchanger HE2.

[0240] The second heat transfer material flow SHTMS 1 to 5 are the flows of heat transfer material 2 in different stages of heat pump HP2, wherein:

[0241] - The second heat transfer material flow SHTMS1 is the flow of heat transfer material HTM2 entering step 3);

[0242] - The second heat transfer material stream SHTMS2 is the stream of heat transfer material HTM2 that leaves step 3) and enters compression step 4);

[0243] - The second heat transfer material flow SHTMS3 is the flow of heat transfer material HTM2 that leaves the compression step 4) and enters the step 5);

[0244] - The second heat transfer material stream SHTMS4 is the stream of heat transfer material HTM2 that leaves step 5) and may optionally enter the recirculation step R2);

[0245] - The second heat transfer material stream SHTMS5 is the stream that leaves the recirculation step R2) and can be recycled as the second heat transfer material stream SHTMS1 to the heat transfer material HTM2 in step 3).

[0246] Step 5) transfer of heat energy from SHTSM3 to regeneration step c)

[0247] In a preferred embodiment, after heat is transferred from heat pump HP1 to heat pump HP2, specifically to the second heat transfer medium flow SHTMS2, there is preferably a compression step 4), wherein the second heat transfer medium flow SHTMS2 in the second heat pump HP2 is compressed to obtain a second heat transfer medium flow SHTMS3 having a higher pressure than the second heat transfer medium flow SHTMS2.

[0248] Compression is preferably achieved in a compressor.

[0249] A compressor is a device used to increase the pressure of at least a portion of a gaseous fluid.

[0250] Compressors are typically positive displacement compressors or dynamic compressors. Positive displacement compressors include reciprocating compressors, which use crankshaft-driven pistons to deliver fluids at higher pressures. Reciprocating compressors can be single-stage or multi-stage. Positive displacement compressors also include rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors, or scroll compressors.

[0251] The compressor can also be a dynamic compressor, such as a centrifugal compressor or an axial compressor.

[0252] Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a reciprocating compressor, or an axial flow compressor.

[0253] Compression can be carried out in one compressor or a series of compressors, depending on the desired pressure increase of the heat transfer material HTM2.

[0254] The heat transfer material HTM2 is used as a heat transfer material under pressure p SHTMS2 and temperature T SHTSM2 The heat transfer material flow SHTMS2 enters the compression step and is under pressure p SHTMS3 and temperature T SHTMS3 The heat transfer material SHTMS3 leaves the compression step.

[0255] The pressure increase during the compression step is Δp (p SHTMS3 -p SHTMS2 Typically, the bar is 1 to 20 bar, preferably 1.2 to 10 bar, and more preferably 1.5 to 3 bar, and the accompanying temperature increase is preferably 20 K to 2000 K, more preferably 25 K to 6 K, and most preferably 30 K to 50 K.

[0256] In a preferred embodiment, the compression step is carried out in a series of two or more compressors, and the heat transfer material HTM2 is water. In this embodiment, an additional stream of heat transfer material HTM2 is fed after each of the compressors in series to increase the amount of gaseous heat transfer material HTM2 produced, at the cost of lowering the temperature of the stream. In this way, the opportunity to generate sufficient steam for regeneration step c) can be obtained. Furthermore, adding additional heat transfer material HTM2 is energy-advantageous compared to a scenario where the same amount of gaseous heat transfer material HTM2 is produced (where no additional heat transfer material HTM2 is introduced after the compression step). Preferably, saturated steam is generated and used for heating in the reboiler HE-R. Injecting water between compressor sections helps reduce the superheating of the steam.

[0257] In addition, the injection of additional heat transfer material HTM2 leads to a reduction in volumetric flow rate and a decrease in the power demand of subsequent compressors in the continuous compression stage.

[0258] Indirect heat transfer to regeneration step c)

[0259] According to a preferred embodiment of the present invention, in step 5), heat energy is transferred from the second heat transfer medium flow SHTMS3 of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium flow SHTMS4 with a reduced heat energy content compared to SHTMS3.

[0260] The transfer of heat energy from the second heat transfer material flow SHTMS3 to the regeneration step c) can occur indirectly or directly, as further explained below.

[0261] Direct heat transfer to regeneration step c)

[0262] In a preferred embodiment of the invention, the transfer of heat energy from the second heat transfer material stream HTMS3 to the regeneration step c) takes place in a heat exchanger HE-R, wherein the loaded absorbent A2 obtained in step b) is heated before entering the regeneration step c).

[0263] The heat exchanger HE-R can replace or supplement the cross-flow heat exchanger to transfer heat from the regenerating absorbent A3 to the loaded absorbent A2 before entering the regeneration step c).

[0264] The heat exchanger HE-R is preferably an indirect heat exchanger.

[0265] When the heat exchanger HE-R is an indirect heat exchanger, HE-R preferably includes:

[0266] -Inlet of the loaded absorbent A2;

[0267] - The outlet of the loaded absorbent A2 has increased thermal energy compared to the loaded absorbent A2 at the inlet of the heat exchanger HE-R;

[0268] - The inlet of the second heat transfer medium flow SHTMS1, at which the second heat transfer medium flow has a pressure p SHTMS1 and temperature T SHTMS1 ;as well as

[0269] - The outlet of the second heat transfer medium flow SHTMS2, at which the second heat transfer medium flow has a pressure p SHTMS2 and temperature T SHTMS2 .

[0270] More preferably, the heat exchanger HE-R is a shell-and-tube heat exchanger or a plate heat exchanger.

[0271] In the case of flue gas, this embodiment may be particularly useful when an intermediate evaporation or flash evaporation step is performed after the cross-flow heat exchanger HE-CF. In this case, at least a portion of the loaded absorbent stream A2 can be reheated before entering the regenerator.

[0272] Recycle step R1

[0273] In the most preferred embodiment, thermal energy is transferred directly from the second heat transfer medium flow SHTMS3 to the bottom of the regenerator in regeneration step c).

[0274] More preferably, heat transfer is achieved through a heat exchanger HE-R connected to the bottom of the regenerator, in which heat exchange occurs indirectly. Most preferably, the indirect heat exchanger HE-R is a reboiler.

[0275] A reboiler typically includes an inlet connected to the bottom of the regenerator, through which absorbent stream AS1 enters the reboiler, and an outlet connected to an inlet at the bottom of the regenerator, through which absorbent stream AS2 exits the reboiler and re-enters the regenerator.

[0276] The reboiler also includes an inlet through which the second heat transfer material stream SHTMS3 enters the reboiler, and an outlet through which the second heat transfer material stream SHTMS4 leaves the reboiler.

[0277] HE-R is preferably a reboiler selected from the group consisting of a kettle reboiler, a thermosiphon reboiler, and a forced circulation reboiler.

[0278] By heating the absorbent stream AS2, acidic gases (especially CO2) are typically desorbed, and the water contained in the absorbent is at least partially evaporated into a stream to propagate the stripping effect, resulting in the further release of acidic gases from the loaded absorbent.

[0279] Further details concerning regeneration step c) and recycling step d) are specified in a later part of this specification.

[0280] https: / / en.wikipedia.org / wiki / Thermal_expansion_valve

[0281] In a preferred embodiment, the method of the present invention includes an additional recycling step R1), wherein the heat transfer material flow HTMS4 obtained in step 3) is expanded to obtain a reduced pressure compared to the heat transfer material flow HTMS4 and is at least partially recycled as heat transfer material flow HTMS1 to the heat transfer medium flow HTMS5 of step 1).

[0282] Expansion is preferably achieved by increasing the pressure p of the heat transfer medium HTMS4. HTMS4 Reduce the pressure p of the heat transfer medium HTMS5 HTMS5 To achieve this.

[0283] Expansion is preferably achieved via a thermal expansion valve. A thermal expansion valve that can be used in the recirculation step R1) is described in... Recycle step R2 The Wikipedia article "Thermal Expansion Valve" is available on p. HTMS4 to p HTMS5 The pressure reduction Δp usually leads to adiabatic flash evaporation of a portion of the heat transfer medium flow HTMS4, and the automatic cooling effect of this adiabatic flash evaporation reduces the temperature of the heat transfer medium flow HTMS4.

[0284] The expansion valve is preferably p HTMS5 equals p HTMS1 And T HTMS5 equal to T HTMS1 The operation and design of the heat transfer material flow HTMS5 can be preferentially recycled as heat transfer material flow HTMS1 to step 1.

[0285] https: / / en.wikipedia.org / wiki / Thermal_expansion_valve

[0286] In a further preferred embodiment, the method of the present invention includes an additional recirculation step R2), wherein the second heat transfer material stream SHTMS4 obtained in step 5) is expanded to obtain a reduced pressure compared to the second heat transfer material stream SHTMS4 and is at least partially recirculated as the second heat transfer material stream SHTMS1 to the second heat transfer medium stream SHTMS5 in step 3).

[0287] Expansion is preferably achieved by increasing the pressure p of the heat transfer medium flow SHTMS4. SHTMS4 Reduce the pressure p of the heat transfer medium flow SHTMS1 SHTMS1 To achieve this.

[0288] Expansion is preferably achieved via a thermal expansion valve. The thermal expansion valve that can be used in step 4) is described in... Sour gas absorption process - absorption step b) The Wikipedia article "Thermal Expansion Valve" is mentioned.

[0289] From p SHTMS4 to p SHTMS5 The pressure reduction Δp causes a portion of the heat transfer medium flow SHTMS4 to undergo adiabatic flash evaporation, and the automatic cooling effect of this adiabatic flash evaporation lowers the temperature of the heat transfer medium flow SHTMS4.

[0290] The expansion valve is preferably p SHTMS5 equals p SHTMS1 And T SHTMS5 equal to T SHTMS1 The way it is operated and designed.

[0291] The heat transfer medium flow SHTMS5 is preferably recycled as heat transfer material flow SHTMS1 to the evaporation process in step 1).

[0292] The advantage of performing at least one of the additional recirculation steps R1 and R2 is that the heat transfer materials HTM1 and HTM2 can be reused in the closed-loop heat pump, thereby saving material costs or preventing environmental pollution associated with the loss of heat transfer materials HTM1 or HTM2 if environmentally harmful heat transfer materials HTM1 or HTM2 are selected.

[0293] If the heat transfer material HTM2 is water / steam, it is not necessary to force the second heat transfer material stream SHTM4 to expand to recirculate the water, as the water can be discarded into the environment or used to transfer heat to other processes. In this case, it is preferable not to directly recirculate the second heat transfer material stream SHTMS4 to the heat exchanger HE-1.

[0294] However, it is preferable that if the heat transfer material HTM2 is water or another heat transfer material HTM2, the method of the present invention further includes a recycling step R2 in order to save resources, especially if the availability of heat transfer material HTM2 is limited on the production site.

[0295] The invention may also include more than two heat pumps connected in series, such as three or four heat pumps, where the condenser of one heat pump is the evaporator of the subsequent heat pump. The last heat pump in a series of two or more heat pumps will perform the function of heat pump HP2 in the series of two heat pumps. For the same reason, the heat transfer material of the last heat pump in series is preferably water, which is the preferred heat transfer material HTM2 in heat pump HP2.

[0296] Absorbent:

[0297] According to the invention, fluid stream FS2 is deacidified in absorption step b), wherein the cooled fluid stream FS2 is contacted with absorbent A1 in the absorber to obtain absorbent A2 loaded with acidic gas and fluid stream at least partially deacidified.

[0298] Absorber:

[0299] The absorbent contains at least one amine.

[0300] The following amines are preferred:

[0301] i) Amines having formula I:

[0302] NR 1 (R 2 )2(I)

[0303] Where R 1Selected from C2-C6-hydroxyalkyl, C1-C6-alkoxy-C2-C6-alkyl, hydroxy-C1-C6-alkoxy-C2-C6-alkyl, and 1-piperazinyl-C2-C6-alkyl, and R 2 Independently selected from H, C1-C6-alkyl, and C2-C6-hydroxyalkyl;

[0304] ii) Amines having formula II:

[0305] R 3 R 4 NX-NR 5 R 6 (II)

[0306] Where R 3 R 4 R 5 and R 6 Independently selected from H, C1-C6-alkyl, C2-C6-hydroxyalkyl, C1-C6-alkoxy-C2-C6-alkyl, and C2-C6-aminoalkyl, and X is C2-C6-alkylene, -X 1 -NR 7 -X 2 -or-X 1 -OX 2- , where X 1 and X 2 Independently, it is a C2-C6-alkylene group, and R 7 It is H, C1-C6-alkyl, C2-C6-hydroxyalkyl, or C2-C6-aminoalkyl;

[0307] iii) A 5- to 7-membered saturated heterocycle having at least one nitrogen atom in the ring and may contain one or two additional heteroatoms selected from nitrogen and oxygen, and

[0308] iv) Its mixture.

[0309] Specific examples of preferred amines are:

[0310] i) 2-Aminoethanol (monoethanolamine), 2-(methylamino)ethanol, 2-(ethylamino)ethanol, 2-(n-butylamino)ethanol, 2-amino-2-methylpropanol, N-(2-aminoethyl)piperazine, methyldiethanolamine, ethyldiethanolamine, dimethylaminopropanol, tert-butylaminoethoxyethanol (TBAEE), 2-amino-2-methylpropanol, diisopropanolamine (DIPA);

[0311] ii) 3-Methylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, 2,2-dimethyl-1,3-diaminopropane, hexamethylenediamine, 1,4-diaminobutane, 3,3-iminodipropylamine, tris(2-aminoethyl)amine, bis(3-dimethylaminopropyl)amine, tetramethylhexamethylenediamine;

[0312] iii) Piperazine, 2-methylpiperazine, N-methylpiperazine, 1-hydroxyethylpiperazine, 1,4-bishydroxyethylpiperazine, 4-hydroxyethylpiperidine, homopiperazine, piperidine, 2-hydroxyethylpiperidine, triethylenediamine (TEDA), and morpholine; and

[0313] iv) Its mixture.

[0314] In a preferred embodiment, the absorbent comprises at least one of the following amines: monoethanolamine (MEA), methylaminopropylamine (MAPA), piperazine (PIP), diethanolamine (DEA), triethanolamine (TEA), diethylethanolamine (DEEA), diisopropanolamine (DIPA), aminoethoxyethanol (AEE), tert-butylaminoethoxyethanol (TBAEE), dimethylaminopropanol (DIMAP), and methyldiethanolamine (MDEA), triethylenediamine (TEDA), or a mixture thereof.

[0315] Other amines that can be introduced into this process are tert-butylaminopropanediol, tert-butylaminoethoxyethylmorpholine, tert-butylaminoethylmorpholine, methoxyethoxyethoxyethyl-tert-butylamine, and tert-butylaminoethylpyrrolidone.

[0316] The amine is preferably a sterically hindered amine or a tertiary amine. A sterically hindered amine is a secondary amine, wherein the amine nitrogen is bonded to at least one secondary carbon atom and / or at least one tertiary carbon atom; or a primary amine, wherein the amine nitrogen is bonded to a tertiary carbon atom. A preferred sterically hindered amine is tert-butylaminoethoxyethanol. Preferred tertiary amines are methyldiethanolamine and triethylenediamine (TEDA).

[0317] If the objective is to completely or almost completely remove CO2 from the fluid stream, the absorbent preferably contains an activator when the amine present in the absorbent is a sterically hindered or tertiary amine. The activator is typically a sterically unhindered primary or secondary amine. In these sterically unhindered amines, at least one amino group has its nitrogen atom bonded only to a primary carbon atom and a hydrogen atom. If the objective is only to remove a portion of these gases present in the fluid stream, such as selectively removing H2S from a fluid stream containing H2S and CO2, the absorbent preferably does not contain any activator.

[0318] Spatially unhindered primary or secondary amines that can be used as activators are selected from, for example, alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), ethylaminoethanol, 1-amino-2-methyl-prop-2-ol, 2-amino-1-butanol, 2-(2-aminoethoxy)ethanol, and 2-(2-aminoethoxy)ethylamine; and polyamines such as hexamethylenediamine, 1,4-diaminobutane, 1,3-diaminopropane, 3-(methylamino)propylamine (MAPA), and N-(2-hydroxyethyl)amine. Ethylenediamine, 3-(dimethylamino)propylamine (DMAPA), 3-(diethylamino)propylamine, N,N'-bis(2-hydroxyethyl)ethylenediamine, 5-, 6-, or 7-membered saturated heterocycles having at least one NH group in the ring, which may contain one or two additional heteroatoms selected from nitrogen and oxygen, such as piperazine, 2-methylpiperazine, N-methylpiperazine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-aminoethyl)piperazine, homopiperazine, piperidine, and morpholine.

[0319] Particularly preferred are 5-, 6-, or 7-membered saturated heterocycles having at least one NH group in the ring and may contain one or two additional heteroatoms selected from nitrogen and oxygen. Piperazine is very particularly preferred.

[0320] The molar ratio of the activator to the sterically hindered amine or tertiary amine is preferably in the range of 0.05 to 1.0, and more preferably in the range of 0.05 to 0.7.

[0321] Absorbents typically contain 10% to 60% amines by weight.

[0322] In one embodiment, the absorbent comprises tertiary amine methyl diethanolamine and the activator piperazine.

[0323] In a preferred embodiment, the absorbent comprises

[0324] A) At least one cyclic amine compound having only a tertiary amine group, and

[0325] B) At least one cyclic amine compound having at least one sterically unhindered secondary amine group.

[0326] The total concentration of A) + B) is 10% to 60% by weight.

[0327] Such absorbents are disclosed in EP 2391435. Most preferably, amine A) is triethylenediamine (TEDA) and activator amine B) is piperazine.

[0328] The absorbent may additionally contain a physical solvent. Suitable physical solvents are, for example, N-methylpyrrolidone, tetramethylene sulfone, and polyethylene glycol dialkyl ethers such as polyethylene glycol methyl isopropyl ether (SEPASOLV MPE) and polyethylene glycol dimethyl ether (SELEXOL). The physical solvent is typically present in the absorbent in an amount of 1% to 60% by weight, preferably 10% to 50% by weight, and especially 20% to 40% by weight.

[0329] In a preferred embodiment, the absorbent comprises less than 10% by weight, for example less than 5% by weight, and particularly less than 2% by weight of an inorganic alkaline salt, such as potassium carbonate.

[0330] Absorbents may also contain additives such as corrosion inhibitors, antioxidants, enzymes, and defoamers. Typically, the amount of such additives ranges from approximately 0.01% to 3% by weight of the absorbent.

[0331] The absorber may be supplied with fresh absorbent, or it may be supplied with absorbent that has been regenerated in recycling step c). Supplying fresh absorbent means that the components of the absorbent have not yet passed through steps b) to d). Supplying regenerated absorbent requires that at least a portion of the components of the absorbent have passed through steps b) to d).

[0332] The absorbent is preferably aqueous. This means that various different components of the absorbent, such as amines, methanol, physical solvents, and additives, can be mixed with water in the amounts described above.

[0333] Regeneration step c):

[0334] Preferably, in step b), the fluid flow FS2 is brought into contact with the absorbent in the absorber.

[0335] The absorber is preferably an absorption tower or absorption column, such as a tower or tray tower with random or structured packing.

[0336] An absorber typically includes an absorption zone and an optional rewashing zone.

[0337] The absorption zone is considered to be the section of the absorption tower where the fluid flow comes into mass transfer contact with the absorbent.

[0338] The fluid flow preferably contacts the absorbent in a countercurrent manner within the absorption zone.

[0339] To improve contact with the absorbent and provide a large mass transfer interface, the absorption zone typically includes internal components such as random packing, structured packing, and / or trays, such as valve trays, bubble cap trays, Soman trays, or sieve trays.

[0340] If the absorption zone includes random or structured packing, the height of the random / structured packing in the absorption zone is preferably in the range of 5 to 20 m, more preferably in the range of 6 to 15 m, and most preferably in the range of 8 to 14 m.

[0341] If the absorption zone includes trays, the number of trays in the absorption zone is preferably in the range of 8 to 30, more preferably 12 to 25, and most preferably 15 to 23.

[0342] In the case of towers with random or structured packing, the absorption zone can be divided into one or more sections, preferably two to four sections. Support and holding trays and / or distributor trays can be arranged between the individual sections of the absorption zone, and these trays improve the distribution of the absorbent across the entire cross-section of the tower.

[0343] The temperature of the absorbent introduced into the absorption zone

[0344] Typically, the temperature is from about 0°C to 60°C, preferably from 10°C to 50°C, and more preferably from 25°C to 50°C.

[0345] The pressure in the absorber depends on the pressure and type of the fluid flow FS2 entering the absorber.

[0346] When the fluid flow FS2 is a synthesis gas, the pressure in the absorber is typically in the range of 5 to 120 bar, more preferably 10 to 100 bar, and most preferably 10 to 60 bar.

[0347] When the fluid flow FS2 is flue gas, the pressure in the absorber is typically preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1.3 bar, and even more preferably 0.9 to 1.2 bar. Most preferably, when the fluid flow FS2 is flue gas, the absorber operates at atmospheric pressure.

[0348] The feed point of the introduced fluid flow is preferably below or within the lower region of the absorption zone. The feed is preferably evenly distributed across the cross-section of the absorber via a gas distributor.

[0349] An absorber may include one or more inlet points for the introduced absorbent. For example, an absorber may include an inlet point for fresh absorbent A1 and an inlet point for regenerated absorbent A3. The fresh and regenerated absorbents may alternatively be fed together into the absorber via a single inlet point. This one or more inlet points are preferably located above or within the upper region of the absorption zone. Individual components of the absorbent, such as makeup water, may also be fed via the fresh absorbent inlet point.

[0350] If the absorber has an optional rewashing zone, the feed is preferably located between the absorber zone and the rewashing zone.

[0351] The contact between the fluid flow and the absorbent in the absorption zone provides at least a partially deacidified fluid flow FS3 and an absorbent loaded with acidic gas.

[0352] In the upper region of the absorber, there is typically an extraction point for the deacidification fluid flow FS3. A demister can be installed in the region of the extraction point to separate any liquid residue of the absorbent or detergent from the departing fluid flow.

[0353] In the lower region of the absorber, preferably at the bottom, there is usually an extraction point for the loaded absorbent FS2.

[0354] Optionally, the at least partially deacidified fluid flow FS3 may be contacted with the washing liquid in one or more rewash zones (collectively, “rewash zones”).

[0355] The washing liquid is more preferably an aqueous liquid. The washing liquid can be a liquid inherent to the process, i.e., an aqueous liquid obtained elsewhere in the process, or an aqueous liquid supplied from an external source. Preferably, the washing liquid includes condensate (referred to as absorber top condensate) and / or fresh water formed during downstream cooling operations of the deacidification fluid stream.

[0356] The rewash zone is typically the section of the absorber above the feed point of the absorbent.

[0357] The rewash zone preferably has random packing, structured packing, and / or trays to enhance the contact between the fluid flow and the washing liquid. The rewash zone particularly features trays, especially valve trays, bubble cap trays, Soman trays, or sieve trays.

[0358] The rewashing zone includes preferably 1 to 7, more preferably 2 to 6, and most preferably 3 to 5 trays, or preferably 1 to 6 m, more preferably 2 to 5 m, and most preferably 2 to 3 m of packing height (random packing / structured packing).

[0359] The washing solution is typically introduced above the rewash zone or into the upper region of the rewash zone. The washing solution used can be any of the washing solutions described above.

[0360] The washing liquid can be recycled via a rewash zone. This is achieved, for example, by collecting the washing liquid below the rewash zone using a suitable collection tray and pumping it to the upper part of the rewash zone using a pump. The recycled washing liquid can be cooled, preferably to a temperature of 20°C to 70°C, particularly 30°C to 60°C. This is advantageously achieved by recirculating the washing liquid through a cooler. To avoid any accumulation of the washed absorbent components in the washing liquid, it is preferable to discharge a sub-stream of the washing liquid from the rewash zone.

[0361] By contacting the at least partially deacidified fluid stream FS3 with the washing liquid, entrained absorbent components, such as amines, can be washed away. When more water is discharged via the exit stream than is introduced via the inlet stream, contact with the aqueous washing liquid can further improve the water balance of the process.

[0362] As described above, the deacidification fluid flow FS3 is preferably drawn out via an extraction point at the top of the absorber.

[0363] Alternatively, the deacidification fluid flow FS3 can be directed through the condenser.

[0364] The condenser used can be, for example, a condenser with cooling coils or spiral tubes, a plate heat exchanger, a jacketed tube condenser, or a shell-and-tube heat exchanger.

[0365] The condenser typically operates at a temperature range of 10°C to 60°C, preferably 20°C to 50°C, and more preferably 20°C to 30°C.

[0366] The water content of the deacidification fluid flow is typically 80%-100% of the saturation concentration of water in the fluid flow under existing temperature and pressure conditions.

[0367] Step b) Provide absorbent A2 that is at least partially loaded with acidic gas.

[0368] The loaded absorbent A2 can be directly fed into the regeneration step c).

[0369] Expansion step (optional):

[0370] In a particular embodiment of the method of the present invention, the loaded absorbent A2 is first subjected to an expansion step before being introduced into the regeneration step c).

[0371] In the expansion step, the loaded adsorbent A2 is typically directed into one or more expansion containers.

[0372] If the pressure in the absorber is higher than the pressure in the regenerator, the loaded absorbent can be expanded into the expansion vessel through the throttle valve.

[0373] If the fluid flow FS2 is syngas, the loaded adsorbent is preferably expanded to a pressure of 3 to 15 bar, preferably 4 to 12 bar, and more preferably 5 to 10 bar.

[0374] Expansion typically leads to the desorption of so-called flash gases. Flash gases can be directed back into the absorption chamber by means of a compressor, or incinerated to generate energy or combusted in situ.

[0375] If the fluid stream FS2 is flue gas, it is preferable to pump the loaded absorbent into an expansion vessel located downstream of the cross-flow heat exchanger HE-CF. In this case, the pump typically increases the pressure of the fluid stream FS2 by approximately 2 to 8 bar gauge pressure, allowing it to expand into the expansion vessel, which preferably operates at a pressure slightly higher than that of the regenerator. The effect of the expansion step is generally enhanced by the temperature increase of the fluid stream FS2 as it passes through the cross-flow heat exchanger HE-CF. The advantage of performing an additional expansion step is that at least a portion of the oxygen contained in the fluid stream FS2 can be flashed away, which negatively impacts the desired CO2 purity.

[0376] Flash vessels are typically containers without any specific internal components. A preferred type of flash vessel is the so-called flash drum. Alternative flash vessels include towers with internal components such as random packing, structured packing, or trays.

[0377] In the upper region of the flash vessel, there is typically a gas extraction port for converting the gas into a vapor phase. A demister can preferably be located in the region of the gas extraction port. If necessary, the acidic gases present can be separated from the flash gas in a separate absorber. Typically, for this purpose, a sub-stream of the regenerated solvent is supplied to an additional absorber.

[0378] At the bottom of the flash evaporator, absorbent A2, which is at least partially loaded with acidic gas that has not yet been converted into the gas phase, is typically extracted and directed to regeneration step c.

[0379] Regenerator:

[0380] According to the invention, an adsorbent A2 loaded with at least a portion of an acidic gas is fed into a regeneration step C), wherein at least a portion of the loaded adsorbent A2 obtained from step b) is regenerated in a regenerator to obtain an at least partially regenerated adsorbent A3 and a gaseous stream GS containing at least one acidic gas.

[0381] The gaseous stream GS may contain residual water that has not yet been separated in the rewash zone.

[0382] Prior to introducing regeneration step c), it is preferable to guide the adsorbent A2, which is at least partially loaded with acidic gas, through the cross-flow heat exchanger HE-CF.

[0383] In the cross-flow heat exchanger HE-CF, the absorbent A2, at least partially loaded with acidic gas, is preferably heated to a temperature in the range of 50°C to 150°C, more preferably 70°C to 130°C, and most preferably 80°C to 110°C. In a particular embodiment, the regenerated absorbent A3, drawn from the bottom of the regenerator, is used as the heating medium in the heat exchanger HE-CF. The advantage of this embodiment is that the thermal energy from the regenerated absorbent A3 in stage c) can be used to heat the loaded absorbent A2 from step b) in the heat exchanger HE-CF. In this way, the energy cost of the entire process can be further reduced, and the energy requirement in the reboiler of the regeneration step c) can be reduced.

[0384] In a further preferred embodiment—as described in more detail above—the second heat transfer material flow SHTMS3 is used as the heating medium in the heat exchanger HE-R, which is a complement to or replacement of the cross-flow heat exchanger HE-CF.

[0385] Re-wash zone:

[0386] According to the present invention, the regeneration step is performed in a regenerator.

[0387] Regenerators are typically configured as stripping towers.

[0388] The regenerator preferably includes a regeneration zone and a reboiler.

[0389] The regenerator is preferably operated at a top pressure in the range of 0.5 to 5 bar, more preferably 0.7 to 4 bar, and even more preferably 0.9 to 2.5 bar.

[0390] At the bottom of the regenerator, a liquid extraction port for the regenerator absorbent A3 is usually provided.

[0391] At the top of the regenerator, there is typically a gas extraction port for the gaseous flow GS. The demister is preferably installed in the area of ​​the gas extraction port.

[0392] Regenerators typically have a regeneration zone located above the bottom and below the rewash zone. In this context, the regeneration zone is considered to be the area of ​​the regenerator where the loaded absorbent comes into contact with the steam generated in the reboiler.

[0393] To improve and provide a large mass transfer interface, the regeneration zone typically includes internal components such as random packing, structured packing, and / or trays, such as valve trays, bubble cap trays, Soman trays, or sieve trays.

[0394] If the regeneration zone includes structured or random packing, the height of the structured / random packing in the regeneration zone is preferably in the range of 5 to 15 m, more preferably in the range of 6 to 12 m, and most preferably in the range of 8 to 12 m.

[0395] If the regeneration zone includes trays, the number of trays in the regeneration zone is preferably in the range of 10 to 30, more preferably 15 to 25, and most preferably 17 to 23.

[0396] In the case of a tower with random or structured packing, the regeneration zone can be further divided into multiple sections, preferably two to four sections. Support and holding trays and / or distributor trays can be arranged between the sections of the regeneration zone, and these trays improve the distribution of liquid across the entire cross-section of the regenerator.

[0397] Typically, it is preferable to introduce the loaded absorbent A2 into the regenerator in the upper region or above the regeneration zone and below the rewash zone.

[0398] In the regeneration zone, the vapor generated in the evaporator typically operates countercurrently with the absorbent flowing downward through the regeneration zone.

[0399] The area below the regeneration zone in a regenerator is often referred to as the bottom.

[0400] In this region, the absorbent is typically collected and (i) fed as absorbent stream AS1 via a pipe to the reboiler HE-R through a liquid extraction port in the lower region of the regenerator, and / or (ii) partially recycled back into the absorber as regenerated absorbent A3.

[0401] The bottom can be separated by a collection tray positioned between the bottom outlet and the feed point of the steam generated in the evaporator.

[0402] Typically, at least a portion of the regenerated absorbent A3 is directed as absorbent stream AS1 from the bottom outlet of the regenerator into the reboiler.

[0403] Preferably, the bottom extract from the regenerator is completely directed into the reboiler as absorbent stream AS1.

[0404] Reboilers (HE-R) are typically kettle reboilers, natural circulation reboilers, thermosiphon reboilers, or forced circulation reboilers.

[0405] The reboiler HE-R of the regenerator is preferably located outside the regenerator and connected to the bottom outlet via a pipe.

[0406] The reboiler HE-R is typically operated at a temperature range of 100°C to 150°C, preferably 105°C to 140°C, and most preferably 110°C to 130°C.

[0407] In the reboiler HE-R, typically at least a portion of the bottom extract is evaporated and returned to the regenerator as absorbent stream AS2. Preferably, absorbent stream AS2 is fed into the regenerator below the regeneration zone, and more preferably to the bottom of the regenerator.

[0408] If an additional collection tray is provided at the bottom, it is preferable to feed the steam generated in the reboiler below the collection tray.

[0409] Condensation step:

[0410] In a preferred embodiment, the regenerator has a rewashing zone above the regeneration zone, particularly preferably above the feed point of the loaded absorbent A2.

[0411] The rewashing zone is usually a section with the regenerator located above the regeneration zone.

[0412] The rewashing zone preferably has internal components, particularly random packing, structured packing, and / or trays, to enhance the contact between the fluid flow and the washing liquid. Particularly preferred is that the washing section has trays, particularly valve trays or bubble cap trays.

[0413] In a preferred embodiment, the internal components are random packing and / or structured packing. The packing height (random packing / structured packing) is preferably in the range of 1 to 10 m, more preferably 2 to 8 m, and most preferably 3 to 6 m.

[0414] In a very particularly preferred embodiment, the rewashing zone has trays, especially valve trays or bubble cap trays, the number of which is preferably in the range of 2 to 10, more preferably 2 to 8, and most preferably 2 to 6.

[0415] The washing solution can be introduced into the upper area of ​​the rewash zone or introduced above the rewash zone.

[0416] The washing solution used is typically an aqueous or slightly acidic aqueous solution, especially water. The temperature of the washing solution is typically in the range of 10°C to 60°C, preferably in the range of 20°C to 55°C, and more preferably in the range of 30°C to 40°C.

[0417] In the rewash zone, any residual amines entrained in the absorbent can be washed out, leaving the acidic exhaust gas GS leaving the regenerator essentially amine-free. The water content of the gas stream obtained at the top of the regenerator can be further reduced in the rewash zone because contact with the cooler detergent can cause some of the steam water to condense.

[0418] Compression and / or liquefaction step:

[0419] In a preferred embodiment of the invention, an acidic gas stream GS from the regenerator is introduced into the condensation step.

[0420] In the condensation step, a condensate containing water is condensed from the gas stream (condensate outlet). Preferably, the uncondensed gas phase is discharged to the compression step, as further described below.

[0421] The condensation step is preferably performed such that the gaseous flow GS from stage c) is directed through one or more condensers (regenerator top condensers). The top condenser typically includes a heat exchanger and a vessel in which the liquid and gas phases can be separated (phase separation vessel). However, the heat exchanger and vessel can also be integrated into a single component.

[0422] The top condenser of the regenerator is typically operated in a way that allows water to condense while acidic gases are primarily retained in the gas phase.

[0423] The top condenser used in the regenerator can be, for example, a condenser with cooling coils or spiral tubes, a jacketed tubular condenser, or a shell-and-tube heat exchanger.

[0424] The regenerator top condenser typically operates at a temperature range of 10°C to 60°C, preferably 20°C to 55°C, and more preferably 30°C to 40°C.

[0425] In a preferred embodiment, the gaseous flow GS from stage c) is directed through a regenerator top condenser.

[0426] Optionally, the washing liquid described above can be additionally introduced into the regenerator along with the condensate from the condensation step. This introduction can be achieved via the same feed point. Alternatively, the washing liquid can be introduced via a separate feed point.

[0427] Drying and other purification steps:

[0428] The fluid flow GS preferably contains CO2.

[0429] To prevent this CO2 from being released into the atmosphere, it is preferable to seal the CO2 in a suitable storage location.

[0430] Storage typically requires the gaseous CO2 stream GS to be compressed and optionally cooled into a fluid, which can be transported via pipeline to its destination or as a chemical therefore for other uses. Typical pressures for CO2 in pipelines used for transport are 70 to 200 bar, preferably 90 to 150 bar. Typical pressures for CO2 transported by ship, truck, or train are 5 to 50 bar, preferably 6 to 40 bar, and more preferably 7 to 35 bar.

[0431] Compression is typically achieved in one or more compressors. The compressors are typically configured to receive a gaseous stream GS containing CO2 and compress the gaseous stream to produce a compressed fluid stream CFS.

[0432] Compressors are typically positive displacement compressors or dynamic compressors. Positive displacement compressors include reciprocating compressors, which use crankshaft-driven pistons to deliver fluids at higher pressures. Reciprocating compressors can be single-stage or multi-stage. Positive displacement compressors also include rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors, or scroll compressors.

[0433] The compressor can also be a dynamic compressor, such as a centrifugal compressor or an axial compressor.

[0434] Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a reciprocating compressor, or an axial flow compressor.

[0435] After compression or after each compression step in the compressor, it is preferable to pass the fluid flow CFS through one or more heat exchangers to dissipate the heat from the compressed fluid or to use the heat of compression as a heat source to heat other processes or other steps in the gas processing process.

[0436] Alternatively, compression can be supplemented by one or more additional refrigeration steps to liquefy CO2. The CO2 can be cooled in a heat exchanger, which is an evaporator of the heat transfer material, preferably liquid ammonia. The evaporated heat transfer material is then compressed, cooled, and expanded in a conventional refrigeration loop. Two or more refrigeration loops can also be combined in series, which reduces the energy consumption of refrigeration.

[0437] Furthermore, CO2 can be compressed, cooled by external water, and expanded to transport temperature, and then compressed again. Preferably, the unliquefied CO2 is separated and recycled back to the compression step. Energy consumption can be reduced by performing compression and decompression (evaporation) in several steps.

[0438] Transport and storage and utilization:

[0439] It is generally preferred to dry the CO2-containing stream GS. Drying can occur before, after, or after one or more of these steps, such as the compression or cooling step.

[0440] Drying is preferably carried out in the form of pressure swing adsorption (PSA), and more preferably in the form of temperature swing adsorption (TSA) or in the form of ethylene glycol drying.

[0441] PSA or TSA can be performed using methods known to those skilled in the art. Standard variant procedures are described, for example, in Nag, Ashis, “Distillation and Hydrocarbon Processing Practices”, PennWell Publishing Group, 2016, ISBN 978-1-59370-343-1 or A. Terrigeol, GPA Europe, Annual Conference, Berlin, Germany, May 23-25, 2012 (https: / / www.cecachemicals.com / export / sites / ceca / .content / medias / downloads / products / dtm / molecular-sieves-contaminants-effects-consequences-and-mitigation.pdf).

[0442] In PSA or TSA, zeolite, activated carbon or molecular sieves are preferred.

[0443] Molecular sieves are preferably used as solid adsorbents in PSA or TSA.

[0444] In the ethylene glycol drying process, liquid adsorbents such as monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG), or tetraethylene glycol (TREG) are preferred. TEG is particularly preferred as a liquid adsorbent.

[0445] Ethylene glycol drying can be performed using process variations known to those skilled in the art. Examples of ethylene glycol drying can also be found, for example, in Nag, Ashis, “Distillation and Hydrocarbon Processing Practices”, PennWell Publishing Group, 2016, ISBN 978-1-59370-343-1.

[0446] Similarly, other components such as carbonyl sulfide (COS) and hydrogen sulfide can be removed by installing additional filters and adsorbers.

[0447] Recycle step d):

[0448] It is preferable to transport the fluid stream CFS to its storage site or its final use location. CO2 can be transported via pipelines or by means of transport such as trucks, trains and ships.

[0449] A suitable storage location is a suitable geological structure, such as a depleted oil and gas reservoir, a mine, and salt rock or other rock formations.

[0450] CO2 can also be used in the food, petroleum, and chemical industries.

[0451] The preferred use of CO2 in the food industry is the carbonization of beverages.

[0452] Other uses of captured carbon dioxide include enhancing oil recovery or converting it into fuels, cement, minerals, or chemicals, or using it as a material for fire extinguishers, as a solvent, or as an inert gas or refrigerant.

[0453] Summary:

[0454] According to the present invention, the regeneration absorbent A3 obtained at the bottom of the regenerator from step c) is returned to the absorption step b).

[0455] The regenerated absorbent is preferably recycled at one of the regenerated absorbent feed points of the absorber as described above.

[0456] 2nd aspect - Apparatus for producing a de-acidified fluid stream

[0457] The method of the present invention allows the use of the thermal energy inherent in the heat flow HS1, and in particular the fluid flow FS1, to provide energy for the energy-intensive regeneration step c).

[0458] The advantage of using two or more heat pumps connected in series is that the thermal energy from the heat flow HS1, especially FS1, can be increased to a level that can generate steam in heat pump HP2, which can then be used to transfer heat to regeneration step c). Therefore, the flow generated in heat pump HP2 can effectively replace the process steam typically required as the heat source in regeneration step c). Thus, using two heat pumps in series can replace the need for a separate process steam production process installed on-site at the sour gas removal unit, or the need for steam turbines such as back-pressure turbines or exhaust condensing turbines to generate process steam. Therefore, the present invention is particularly useful where process steam is not readily available at the sour gas removal unit site. Moreover, in sites where process steam is readily available, the method according to the invention can be used as an alternative to producing process steam, thereby allowing potentially limited process steam resources to be used for other purposes or allowing for a reduction in power plant power losses associated with process steam production. Additionally, the method of the present invention is an interesting alternative in the design of new power plants combined with sour gas removal units for carbon capture, as it can reduce the need to divert energy used for steam production to power the recirculation step. In addition, the method of the present invention is a useful way to electrify steam production, so that the steam required in the amine gas treatment process can be provided by “green” electricity from renewable resources.

[0459] In a preferred embodiment of the invention, the final heat transfer material HTM of the last heat pump HP in series is water. In this embodiment, steam can be generated as the heat transfer material stream to the reboiler. Using water as the final heat transfer material greatly improves the flexibility of the method, because excess steam can be diverted to other steam consumers or insufficient steam can be compensated from other steam providers (e.g., an internal steam supply network). In this way, fluctuations in the feed stream FS2 to the absorber can be at least partially compensated. Such fluctuations may be caused by a decrease in demand for the heat stream HS1, fluid stream FS1, or fluid stream FS2 production process. Such fluctuations may occur when the increased availability of renewable wind and solar energy leads to a decrease in demand for energy provided by fossil fuels.

[0460] In a preferred embodiment of the invention, the thermal energy from the gaseous heat flow HS1, particularly the fluid flow FS1, is transferred to the regeneration step via an intermediate cooling loop comprising a direct contact cooler DCC and a cooling material CM. The advantage of direct heat exchange is the increased exchange area between the two fluid flows HS1 and CMS1, which reduces thermal resistance and maximizes thermal efficiency. Furthermore, due to the high heat transfer rate per volume and because fouling and corrosion are generally not problems, direct heat exchangers typically have lower operating and capital costs than indirect heat exchangers. Additionally, expensive equipment such as blowers or fans required to transport fluid flows FS1 and FS2 in indirect gas-liquid heat exchangers can be reduced or even eliminated in direct heat exchangers because of the lower pressure drop compared to indirect heat exchangers.

[0461] The method of the present invention achieves a specific efficiency when the following conditions are met:

[0462] - Use water as the cooling medium in CMS1 and CMS2.

[0463] - Use ammonia, butane, or R1233zd(e) as the heat transfer material HTM1; and

[0464] - Use water as the heat transfer material HTM2.

[0465] When this combination of cooling medium and heat transfer material is used, exceptionally high coefficient of performance values ​​for heat pumps can be achieved, and particularly flexible methods can be obtained.

[0466] In a preferred embodiment of the invention, the method of the invention can be combined with additional heat pumps designed to transfer heat energy from other heat sources present in the gas processing process.

[0467] Other heat sources of this kind include, but are not limited to, the heat sources HS described above, including but not limited to:

[0468] - The heat absorbed in the absorber can be utilized in the intercooler or by integrating a heat exchanger into the absorber.

[0469] -If the rewash zone is equipped with a pump and cooler, the heat absorbed in the rewash zone at the top of the absorber...

[0470] - The heat of condensation of the condensate at the head of the absorber or regenerator

[0471] - The heat of compression during the compression step, which is generated when the gaseous flow GS is compressed into a supercritical fluid.

[0472] Using these additional measures can help reduce the energy requirements for carbon capture and storage, and even further lead to a reduction in the transfer of electricity from power plants to gas processing units.

[0473] Figures 1 to 4

[0474] In a second aspect, the present invention relates to an apparatus for deacidifying a fluid stream according to claim 17.

[0475] Preferred apparatus for performing the method of the present invention is described in Figure 1 middle.

[0476] These figures each illustrate an apparatus for deacidifying a fluid stream, the apparatus including...

[0477] a) An absorber having

[0478] a. The inlet of fluid flow FS2;

[0479] b. The outlet of the deacidification fluid flow FS3;

[0480] c. Inlet of absorbent stream A1;

[0481] d. The inlet of the regenerated absorbent stream A3; and

[0482] e. The outlet of the loaded absorbent stream A2;

[0483] b) A regenerator, which has

[0484] a. Inlet of the loaded absorbent stream A2;

[0485] b. The outlet of the regenerated absorbent stream A3;

[0486] c. The outlet of the acidic gas stream GS;

[0487] c) Heat pump HP1, which includes

[0488] a. Heat exchanger HE1, which has

[0489] - The first inlet of heat flow HS1 and the outlet of heat flow HS2, or the first inlet of cooling medium flow CMS2 and the outlet of cooling medium flow CMS3; and

[0490] - The second inlet of heat transfer medium flow HTMS1 and the second outlet of heat transfer medium flow HTMS2;

[0491] b. One or more compressors connected in series, wherein the inlet of the first compressor is connected to the second outlet of the heat transfer medium flow HTMS2 from the heat exchanger HE1, and the outlet of the last compressor in the series has the outlet of the compressed heat transfer medium flow HTMS3.

[0492] d) Heat pump HP2, which is connected in series with heat pump HP1 via heat exchanger HE2, the heat exchanger having a first inlet of heat transfer medium flow HTMS3 and an outlet of heat transfer medium flow HTMS4, a second inlet of second heat transfer medium flow SHTMS1 and a second outlet of second heat transfer medium flow SHTMS2, and wherein heat pump HP2 additionally includes;

[0493] a. One or more compressors connected in series, wherein the inlet of the first compressor is connected to the second outlet of the heat transfer medium flow SHTMS2 from the heat exchanger HE2, and the outlet of the last compressor in the series has the outlet of the compressed heat transfer medium flow SHTMS3.

[0494] b. One or more optional feed points for additional heat transfer material HTM2 between compression steps to increase the amount of gaseous heat transfer material HTM2 that can be produced (this embodiment is particularly preferred if the heat transfer material HTM2 is water, in order to increase the amount of steam that can be produced in the heat pump HP2).

[0495] c. Heat exchanger HE-R

[0496] d. It has an inlet for the second heat transfer medium flow SHTMS3 and an outlet for the second heat transfer material flow SHTMS4.

[0497] The heat exchanger HE-R has an inlet connected to the absorbent stream AS1 of the regenerator and an outlet connected to the absorbent stream AS2 of the regenerator.

[0498] Figure 2 An embodiment of a device suitable for directly transferring thermal energy from heat flow HS1 to heat pump HP1 is shown, wherein the inlet of heat exchanger HE1 is configured to directly receive heat flow HS1.

[0499] Figure 3 An embodiment of a device suitable for directly transferring thermal energy from a heat flow HS1 is shown, wherein the heat flow HS1 is a fluid flow FS1.

[0500] Figure 3 An apparatus suitable for indirectly transferring thermal energy from heat flow HS1 (in this case, fluid flow FS1) to heat pump HP1 via an intermediate cooling loop including heat exchanger HE-C, wherein the inlet of heat exchanger HE1 is configured to receive cooling medium flow CMS2. Figure 3 Additionally, a heat exchanger HE-C is included, which has an inlet for hot flow HS1 (FS1 in this case) and an outlet for hot flow HS2 (FS2 in this case), an inlet for cooling medium flow CMS1, and an outlet for cooling medium flow CMS2. Figure 4In this embodiment, the heat exchanger HE-C is configured as a direct contact cooler, which constitutes a preferred embodiment of the invention.

[0501] Figure 3 A preferred embodiment is shown, which is consistent with Figure 1 The difference is that the heat pump HP2 is configured as an open-loop heat pump, which preferably operates using water as the heat transfer material HTM2.

[0502] In all the attached figures, the absorber is configured as an absorption tower.

[0503] The absorber preferably has an absorption zone. In the context of this invention, the absorption zone is considered to be the section of the absorber in which the fluid flow comes into mass transfer contact with the absorbent. To improve contact and provide a large mass transfer interface, the absorption zone preferably includes internal components, preferably random packing, structured packing, and / or trays.

[0504] In a tower with random or structured packing, the absorption zone is preferably divided into two to four packing sections arranged vertically to each other, which are separated from each other by support and holding trays and / or distributor trays.

[0505] If the absorption zone includes random or structured packing, the height of the structured / random packing in the absorption zone is preferably in the range of 5 to 20 m, more preferably in the range of 6 to 15 m, and most preferably in the range of 8 to 14 m.

[0506] If the absorption zone includes trays, the number of trays in the absorption zone is preferably in the range of 8 to 30, more preferably 12 to 25, and most preferably 15 to 23.

[0507] Preferably, the inlet of the fluid flow FS2 to be deacidified is located below or in the lower region of the absorption zone.

[0508] Fresh absorbent A1 can be fed via an inlet in the upper region or above the absorption zone. The supply of fresh absorbent may also include the supply of individual components of the absorbent, such as supplemental water.

[0509] The regenerated absorbent A3 can be fed through the same inlet or through an inlet in the upper region or above the absorption zone.

[0510] Preferably, an outlet for the deacidification fluid flow FS3 is located above the absorption zone, and preferably at the top of the absorption tower.

[0511] The demister (not shown) is preferably installed in the area where the deacidification fluid flow exits.

[0512] In a particularly preferred embodiment, a detergent feed point (not shown) is located in the upper region or above the absorption zone.

[0513] In very specific embodiments, the absorber includes an additional rewashing zone (not shown) above the absorption zone. The rewashing zone is typically configured as a section of the absorber in the form of a rectification section positioned above the feed point of the absorbent. The rewashing zone preferably has random packing, structured packing, and / or trays to enhance contact between the fluid flow and the washing liquid. The rewashing zone particularly features trays, especially valve trays, bubble cap trays, Soman trays, or sieve trays.

[0514] Preferably, a detergent feed point (not shown) is located above the rewash zone. The rewash zone includes preferably 1 to 7, more preferably 2 to 6, and most preferably 3 to 5 trays, or preferably 1 to 6 m, more preferably 2 to 5 m, and most preferably 2 to 3 m of packing height (random packing or structured packing).

[0515] A collection tray (not shown) can be positioned below the rewash zone, where the wash liquid can be collected and recirculated. Recirculation is typically achieved using a pump (not shown) that pumps the wash liquid from the collection tray to the feed point. During recirculation, the wash liquid can be cooled using a heat exchanger (not shown).

[0516] Preferably, a liquid outlet for loading absorbent A2 is present in the lower region of the absorber.

[0517] In a preferred embodiment, a heat exchanger HE-CF exists between the liquid outlet of the loaded absorbent in the absorber and the feed inlet of the loaded absorbent in the regenerator. The heating medium used for this heat exchanger is preferably the recirculated flow of the regenerated absorbent A3 from the bottom of the regenerator to the absorber. In this preferred embodiment, the energy requirement of the entire process can be reduced.

[0518] The HE-CF heat exchanger can be configured as a plate heat exchanger or a shell-and-tube heat exchanger. The heating medium used in the heat exchanger is preferably a bottom flow from the regenerator.

[0519] In the accompanying drawings, the outlet of the loaded absorbent A2 from the absorber is preferably connected to the regenerator via a heat exchanger and a pipeline.

[0520] The regenerator in all the figures preferably includes a regeneration zone, an evaporator, a feed inlet for the loaded absorbent A2, a liquid extraction outlet (outlet) for at least partially regenerated absorbent A3 at the bottom of the regenerator, a rewash zone (not shown), and an outlet in the top region of the regenerator for extracting the acid gas stream GS.

[0521] In this context, the regeneration zone is considered to be the area of ​​the regenerator where the loaded absorbent comes into contact with the steam generated by the reboiler.

[0522] To improve contact and provide a large mass transfer interface, the regeneration zone preferably includes internal components, preferably random packing, structured packing and / or trays.

[0523] In towers with random or structured packing, the regeneration zone is preferably divided into two to four packing sections arranged vertically to each other, which are separated from each other by support and holding trays and / or distributor trays.

[0524] If the regeneration zone includes random or structured packing, the height of the random / structured packing in the regeneration zone is preferably in the range of 5 to 15 m, more preferably in the range of 6 to 12 m, and most preferably in the range of 8 to 12 m.

[0525] If the regeneration zone includes trays, the number of trays in the regeneration zone is preferably in the range of 10 to 30, more preferably 15 to 25, and most preferably 17 to 23.

[0526] The feed inlet of the loaded absorbent A2 is preferably located above or in the upper region of the regeneration zone.

[0527] Figure 2 and Figures 1 to 4 The regenerator in the system additionally includes a reboiler, HE-R.

[0528] The reboiler is preferably a kettle reboiler, a natural circulation evaporator, or a forced circulation evaporator.

[0529] The reboiler HE-R is preferably connected via a pipe to a liquid extraction port at the bottom of the regenerator to introduce the absorbent stream AS1 into the reboiler HE-R. This bottom typically refers to the area below the regeneration zone.

[0530] The absorbent stream AS2 (which is typically a vapor-liquid mixture generated in the reboiler) is preferably introduced into the lower region of the regenerator via a feed point above the liquid extraction port at the bottom but below the regeneration zone.

[0531] In a further preferred embodiment, the bottom of the regenerator is separated by a collection tray (not shown). The absorbent collected therein is supplied to a cross-flow heat exchanger HE-CF. Preferably, the stream AS2 is recirculated back to the regenerator below the collection tray.

[0532] The regenerator in all the accompanying drawings preferably includes an extraction point for the gaseous flow GS formed during regeneration. The extraction point for the gaseous flow GS formed during regeneration is preferably located in the top region of the regenerator. Preferably, a demister (not shown) is present in the region of the extraction point.

[0533] The regenerator in the accompanying drawings preferably includes a rewash zone (not shown) with internal components. The internal components present in the rewash zone are preferably structured or random packing, wherein the packing height (random / structured packing) is preferably in the range of 1 to 10 m, more preferably in the range of 2 to 8 m, and most preferably in the range of 3 to 6 m. Alternatively, the internal components present in the rewash zone are trays. More particularly, the number of trays is preferably in the range of 3 to 20, more preferably 4 to 16, and most preferably 6 to 12. The trays in the washing section can be, for example, valve trays, bubble cap trays, Soman trays, or sieve trays.

[0534] In the accompanying drawings, a separate inlet (not shown) for the washing liquid may be present above or in the upper region of the rewash zone. If additional washing liquid, such as fresh water, is supplied, it is preferable to guide this washing liquid, along with the condensate from the additional condensation step, into the regenerator at the top. Preferably, the extraction point of the gaseous flow GS formed in the regenerator is connected to a top condenser (not shown). The top condenser preferably includes a heat exchanger, a container for phase separation (phase separation container), a gas extraction outlet, and a condensate outlet. The condenser used can be, for example, a condenser with cooling coils or spiral tubes, a jacketed tubular condenser, and a shell-and-tube heat exchanger.

[0535] Figure 1 The illustrated embodiment includes two heat pumps, HP1 and HP2, connected in series, which are configured to transfer thermal energy from heat flow HS1, preferably fluid flow FS1, to regeneration step c.

[0536] exist Figure 2 In this process, heat flow HS1 and heat transfer material flow HTMS1 are fed into heat exchanger HE1 (preferably an indirect gas-liquid heat exchanger) to obtain heat flow HS2 with reduced thermal energy compared to heat flow HS1 and heat transfer material flow HTMS2 with higher thermal energy compared to heat transfer material flow HTMS1. Figure 3 In this context, heat flow HS1 is fluid flow FS1 and heat flow HS2 is fluid flow FS2.

[0537] exist Figure 4 and Figure 1 In this embodiment, heat exchanger HE1 is configured to receive cooling medium flow CMS2 instead of heat flow HS1. In this embodiment, heat exchanger HE1 is preferably an indirect heat exchanger, and more preferably an evaporator.

[0538] In the accompanying drawings, the outlet of heat exchanger HE1 is configured to supply a heat transfer material stream HTMS2 to a compressor, preferably a rotary screw compressor, centrifugal compressor, reciprocating compressor, or axial compressor, wherein the heat transfer material stream HTMS2 is compressed to obtain a heat transfer material stream HTMS3, which is preferably connected to the inlet of heat exchanger HE2 via a pipe. In heat exchanger HE2, the heat energy from the heat transfer material stream HTMS3 of heat pump HP1 is transferred to a second heat transfer material stream HTMS1 of heat pump HP2. Heat exchanger HE2 is preferably an indirect heat exchanger.

[0539] Heat exchanger HE2 includes an additional outlet for a second heat transfer material stream SHTMS2, which is preferably transferred via piping to a second compressor, preferably a rotary screw compressor, centrifugal compressor, or axial compressor, to obtain a second heat transfer material SHTMS3. The compressor outlet of the second heat transfer material stream SHTMS3 is preferably connected to the inlet of heat exchanger HE-R, which is configured as a reboiler for a regenerator. In heat exchanger HE-R, heat energy is transferred from the second heat transfer material stream SHTMS3 to the absorbent stream AS1 to obtain an absorbent stream AS2 with higher heat energy than absorbent stream AS1 and a second heat transfer material stream SHTMS4 with reduced heat energy compared to the second heat transfer material stream SHTMS3. As explained above, the outlet of absorbent stream AS2 of heat exchanger HE-R is preferably connected to an inlet below the regeneration zone of the regenerator.

[0540] In the accompanying drawings, the heat pump HP1 includes a heat exchanger HE1, a heat exchanger HE2, and a compressor connected to the heat exchangers HE1 and HE2.

[0541] exist Figure 2 and Figures 1 to 3 In the heat pump H2, heat exchanger HE2, heat exchanger HE-C, and compressor connected to heat exchangers HE2 and HE-C are included.

[0542] Heat pumps HP1 and HP2 are connected in series, which means that heat exchanger HE2 is the condenser of heat pump HP1's heat transfer material HTM1, and at the same time, it is the evaporator of heat pump HP2's heat transfer material HTM2.

[0543] Figure 4Heat pumps HP1 and HP2 are additionally shown, which further include optional devices configured to perform optional recirculation steps R1 and R2. This additional device includes means for expanding the respective heat transfer material streams HTMS4 and SHTMS4 to obtain respective heat transfer material streams HTMS5 and SHTMS5, which preferably have the same temperature and pressure as the respective heat transfer material streams HTMS1 and SHTMS1, so that they can be recirculated to the inlets of the respective heat exchangers HE1 and HE2. The means for expanding the respective heat transfer material streams is preferably a thermal expansion valve.

[0544] Figures 1 to 4 Heat pumps HP1 and HP2 are shown in series, with heat pump HP2 operating as an open-loop heat pump configured to exclude the recirculation step R2. This embodiment is particularly preferred if the heat transfer material HTM2 of heat pump HP is water.

[0545] 3rd aspect - Transfer of heat energy from a fluid stream to a regeneration step using heat pumps connected in series The equipment shown in the figure can be operated under the process conditions described in the first aspect of the invention.

[0546] Figure 4

[0547] In a third aspect, the present invention relates to the use as described in claim 18.

[0548] The advantage of using two or more heat pumps connected in series is that the thermal energy contained in the heat flow HS1, and especially the fluid flow FS1, can be increased to the level required for stripping acidic gases from a partially loaded absorbent.

[0549] This invention is illustrated by the following examples:

[0550] These examples are based on calculations using simulation models. Phase equilibrium is described using the Pitzer model (KS Pitzer, Activity Coefficients in Electrolyte Solutions, 2nd ed., CRC Press, 1991, Chapter 3, Ion Interaction Approach: Theory). The absorption process is simulated using a mass transfer-based approach; details are given in Asprion (Asprion, N.: Nonequilibrium Rate-Based Simulation of Reactive Systems: Simulation Model, Heat Transfer, and Influence of Film Discretization, Ind. Eng. Chem. Res. (2006) 45 (6), 2054-2069).

[0551] This invention is illustrated by the following examples:

[0552] Example 1 is based on calculations using a simulation model. The phase equilibrium of the carbon capture portion is described using the Pitzer model (KS Pitzer, Activity Coefficients in Electrolyte Solutions, 2nd ed., CRC Press, 1991, Chapter 3, Ion Interaction Approach: Theory). The absorption process is simulated using a mass transfer-based approach; details are given in Asprion (Asprion, N.: Nonequilibrium Rate-Based Simulation of Reactive Systems: Simulation Model, Heat Transfer, and Influence of Film Discretization, Ind. Eng. Chem. Res. (2006) 45 (6), 2054-2069).

[0553] Specifically, for heat pumps, the required thermodynamic data are provided by PC-SAFT (NH3) (Gross, J.; Sadowksi, G.: Industrial & Engineering Chemistry Research, 2002, 41 (22) 5510), and for water, the required thermodynamic data are provided by NBS tables (L. Haar et al., NBS / NCR Steam Tables, New York: Hemisphere Publishing, 1984).

[0554] Example 1 is based on ​ The process scheme is shown in the figure, in which heat is transferred from fluid flow FS1 to a series of heat pumps HP1 and HP2 via an intermediate cooling cycle including a direct contact cooler DCC, and wherein heat pump HP2 is configured as an open-loop heat pump with minor variations as further described below.

[0555] A fluid flow FS1 with a capacity of 1389 t / h, having the composition depicted in Table A below, a temperature of 70°C, and a pressure of 1.01 bar, is fed into the bottom of a heat exchanger HE-C, which is configured as a direct contact cooler (DCC). In HE-C, FS1 is brought into countercurrent contact with water as a cooling medium flow CMS1 to obtain a fluid flow FS2 with a flow rate of 124.1 t / h at a temperature of 35°C and a pressure of 0.99 bar. This fluid flow is slightly compressed to a pressure of 1.07 bar and a temperature of 43.4°C and then introduced into absorption step b). CMS1 with a flow rate of 3233.3 t / h at a temperature of 40°C and a pressure of 2.25 bar is introduced at the top of HE-C. Thermal energy is transferred from the fluid flow FS1 to the cooling medium flow CMS1 to obtain the cooling medium flow CMS2 at the bottom of HE-C. A small portion of CMS2 (150.7 t / h) is removed from this process. A heat flow HS1 from heat flow HS1 (CMS2) with a capacity of 3275 t / h, a temperature of 61.4°C, and a pressure of 1.01 bar is used as the heat flow of a series heat pump, which consists of a first heat pump HP1 using ammonia as the heat transfer material HTM1 and a second heat pump HP2 using water as the heat transfer material HTM2. Heat pump HP1 is designed as a closed-loop heat pump including a regeneration step. Heat pump HP2 is designed as an open-loop heat pump. The heat energy from heat flow HS1 (CMS2) is transferred through the evaporator HE1 of heat pump HP1 to a heat transfer material flow HTMS1 with a flow rate of 408.19 t / h at a temperature of 37.7°C and a pressure of 14.54 bar, to obtain a gaseous heat transfer material flow HTMS2 with a flow rate of 408.19 t / h, a temperature of 37.6°C, and a pressure of 14.49 bar. Furthermore, the cooled medium stream CMS3 is further cooled to 32°C in an additional cooler and pumped to heat exchanger HE-C at a pressure of 4.5 bar. The heat transfer material stream HTMS2 is compressed in a compressor to obtain heat transfer material stream HTMS3 at a pressure of 75.48 bar and a temperature of 197.6°C. Heat transfer material stream HTMS3 is fed into heat exchanger HE2 to obtain a cooled liquid heat transfer material stream HTMS4 at a temperature of 109.6°C and a pressure of 75.43 bar. This heat exchanger serves as the condenser for heat pump HP1 and the evaporator for heat pump HP2. In order to close the loop and recycle the heat transfer material stream HTMS4 to the heat exchanger HE1, the heat transfer material stream HTMS4 is expanded to obtain a cooled heat transfer material stream HTMS5 with a temperature of 37.7°C at a pressure of 14.54 bar. This heat transfer material stream is partially liquid (246.8 t / h) and gaseous (161.4 t / h) and is recycled to the heat exchanger HE1 as the heat transfer material stream HTMS1.In heat exchanger HE2, heat energy is transferred from heat transfer material stream HTMS3 to a second heat transfer material stream SHTMS1 at a pressure of 5 bar, a flow rate of 174.3 t / h, and a temperature of 99.6°C, to obtain a second heat transfer material stream SHTMS2 at a pressure of 1 bar and a temperature of 99.6°C with a flow rate of 174.3 t / h. The second heat transfer material stream SHTMS2 is compressed in three stages, each stage including a compressor. In the first compressor, the pressure is increased to 1.5 bar, and the temperature is increased to 146.1°C. After the first compressor, an additional water flow at a flow rate of 3.8 t / h, a temperature of 99.6°C, and a pressure of 5 bar is added to obtain a second heat transfer material stream SHTMS3 at a pressure of 1.5 bar, a flow rate of 178.1 t / h, and a temperature of 121.4°C. In the second compressor, the second heat transfer material is flowed into STMS3. The pressure was further compressed to 2.3 bar and the temperature to 134.1°C. Another water flow with a temperature of 99.6°C and a pressure of 5 bar was added at a flow rate of 5.8 t / h to obtain a second heat transfer material flow SHTM3 with a temperature of 134.1°C and a pressure of 2.3 bar at a flow rate of 183.9 t / h. In the third compressor, the second heat transfer material stream (SHTMS) is further compressed. To obtain a second heat transfer material flow SHTMS with a pressure of 3.4 bar and a temperature of 184.3°C. An additional water flow with a temperature of 99.6°C, a pressure of 5 bar, and a flow rate of 6.1 t / h is added to the second heat transfer material flow, SHTMS. A second heat transfer material stream, SHTMS3, is obtained with a temperature of 147.8°C, a pressure of 3.4 bar, and a flow rate of 190.0 t / h. The heat energy from the second heat transfer material stream SHTMS3 is transferred to the reboiler of the absorber to maintain a temperature of 127.3°C at the bottom of the absorber. A cooler second heat transfer material stream, SHTMS4, is then obtained with a temperature of 137.3°C and a pressure of 3.34 bar.

[0556] The coefficient of performance (COP), a measure of the performance of a heat pump system, is 2.34.

[0557] Heat pump HP2 operates as an open-loop heat pump, meaning the second heat transfer material stream SHTMS4 is not recirculated to heat exchanger HE2. Alternatively, it is possible that heat pump HP2 operates as a closed-loop heat pump and at least a portion of the second heat transfer material stream SHTMS4 is recirculated to heat exchanger HE2, for example, as stream SHTMS1, or as an additional stream of heat transfer material HTM2, and finally recirculated to the corresponding input stream after the pressure and temperature are regulated through additional expansion, cooling, or compression steps to adjust the characteristics of stream HHTMS4.

[0558] This example demonstrates that the energy contained in the cryogenic fluid flow FS1 can be effectively used for the heating regeneration step c).

[0559] To achieve this in a conventional heat pump, a heat transfer material that undergoes a phase change at the temperature and pressure of heat exchanger HE1 and can be compressed to obtain the high temperatures required in regeneration step c), particularly in the reboiler. Ammonia is not suitable because it would need to be compressed to the pressure at which it becomes supercritical in heat exchanger HE2.

[0560] In Example 1, only the amount of steam required in regeneration step c) is generated. Since the method of the present invention generates steam, the steam can be supplemented by other steam sources, or excess steam can be provided to other consuming entities. Alternatively, excess steam can be dispersed into the environment.

[0561] Table 1: Composition of fluid flow FS1

[0562]

Claims

1. A method for producing a deacidification fluid stream FS3 from a fluid stream containing at least one acidic gas, the method comprising: a) A heat transfer step, wherein heat energy is transferred from heat flow HS1 to a regeneration step c) to obtain a heat flow HS2 with reduced heat energy compared to heat flow HS1; b) An absorption step in which fluid flow FS2 is contacted with absorbent A1 in an absorber to obtain absorbent A2 loaded with acidic gas and fluid flow FS3 at least partially deacidified. c) A regeneration step, wherein at least a portion of the loaded absorbent A2 obtained from step b) is regenerated in a regenerator to obtain at least partially regenerated absorbent A3 and a gaseous stream GS containing at least one acidic gas. d) A recycling step, wherein at least one sub-stream of the regenerated absorbent A3 from step c) is recycled to the absorption step b); The heat transfer step a) includes two or more heat pumps connected in series.

2. The method according to claim 1, wherein, The flow HS1 is fluid flow FS1 and the flow HS2 is fluid flow FS2.

3. The method according to claim 1 or 2, wherein, The heat transfer process includes: 1) In the heat exchanger HE-1 of the first heat pump HP1, heat energy is transferred from heat flow HS1 to heat transfer medium flow HTMS1 of heat transfer material HTM1 to obtain heat transfer medium flow HTMS2 with increased heat energy compared with heat transfer medium flow HTMS1. 2) Compress the heat transfer medium flow HTMS2 in the first heat pump HP1 to obtain a heat transfer medium flow HTMS3 with a higher pressure than the heat transfer medium flow HTMS2. 3) In the heat exchanger HE-2 of the second heat pump HP2, heat energy is transferred from the heat transfer medium flow HTMS3 of the first heat pump HP1 to the second heat transfer medium flow SHTMS1 of the second heat transfer material HTM2, so as to obtain a second heat transfer medium flow SHTMS2 with increased heat energy compared with the second heat transfer medium flow SHTMS1 and a heat transfer medium flow HTMS4 with reduced heat energy content compared with the heat transfer medium flow HTMS3. 4) Compress the second heat transfer medium flow SHTMS2 in the second heat pump HP2 to obtain a second heat transfer medium flow SHTMS3 with a higher pressure than the second heat transfer medium flow SHTMS2. 5) Transfer heat energy from the second heat transfer medium flow SHTMS3 of the second heat pump HP2 to the regeneration step c) to obtain a second heat transfer medium flow SHTMS4 with a reduced heat energy content compared to SHTMS3.

4. The method according to claim 3, wherein, Step 5) is performed by transferring thermal energy from the second heat transfer medium stream SHTMS4 in the heat exchanger HE-R to the absorbent stream AS1 drawn from the regenerator in step c), to obtain an absorbent stream AS2 with increased thermal energy compared to the absorbent stream AS1, and then feeding AS2 into the regenerator in step c).

5. The method according to claim 4, wherein, The heat exchanger HE-R is the reboiler of the regenerator.

6. The method according to claim 3, wherein, In step 5), the transfer of heat energy from the second heat transfer material flow HTMS3 to the regeneration step c) takes place in the heat exchanger HE-R, wherein the loaded absorbent A2 obtained in step b) is heated before entering the regeneration step c).

7. The method according to any one of claims 3 to 5, the method comprising an additional recycling step R1), wherein the heat transfer material flow HTMS4 obtained in step 3) is expanded to obtain a reduced pressure compared to the heat transfer material flow HTMS4 and is at least partially recycled as heat transfer material flow HTMS1 to the heat transfer medium flow HTMS5 of step 1).

8. The method according to any one of claims 3 to 7, the method comprising an additional recirculation step R2), wherein the second heat transfer material stream SHTMS4 obtained in step 5) is expanded to obtain a reduced pressure compared to the second heat transfer material stream SHTMS4 and is at least partially recirculated as the second heat transfer material stream SHTMS1 to the second heat transfer medium stream SHTMS5 in step 3).

9. The method according to any one of claims 3 to 8, wherein, In step 4), the compression of the second heat transfer medium flow 2 includes two or more compression steps.

10. The method according to any one of claims 3 to 9, wherein, After one or more compression steps, additional heat transfer material HTM2 in liquid form is added.

11. The method according to any one of claims 2 to 10, wherein, The temperature of the fluid flow FS1 is in the range of 60°C to 400°C.

12. The method according to any one of claims 2 to 11, wherein, Prior to the heat transfer step a), the fluid flow FS1 is desulfurized in the fluid flow desulfurization step.

13. The method according to claim 12, wherein, After this desulfurization step, the temperature of fluid flow 1 is in the range of 60°C to 200°C.

14. The method according to any one of claims 1 to 13, wherein, The heat transfer material HTM1 is selected from the group consisting of: ammonia, butane, R1233zd(e), R1224yd(z), air, CO2, water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoro-olefins, hydrochlorofluoro-olefins, hydrocarbons, perfluorinated (2-methyl-3-pentanone) and mixtures of two or more thereof, and / or the heat transfer material HTM2 is water.

15. The method according to any one of claims 2 to 14, wherein, In step 1), transferring thermal energy from fluid flow FS1 to heat transfer medium flow HTMS1 of the first heat pump HP1 includes: 1a) Transfer heat energy from FS1 to cooling medium flow CMS1 to obtain a) a fluid flow FS2 with a lower heat energy content compared to FS1, and b) a cooling medium flow CMS2 with an increased heat energy content compared to CMS1; 1b) Transfer at least a portion of the thermal energy contained in the cooling medium CMS2 to the heat transfer medium flow HTMS1, thereby obtaining a heat transfer medium flow HTMS2 with increased thermal energy compared to HTMS1 and a cooling medium flow with reduced thermal energy compared to CMS2 and at least partially recycled to step 1a) as CMS1.

16. The method of claim 14, wherein, The transfer of heat energy from the fluid flow FS1 to the cooling medium flow CMS1 takes place in the heat exchanger HE-C, which is a direct contact cooler.

17. An apparatus for deacidifying a fluid stream, the apparatus comprising: a) An absorber having a. The inlet of fluid flow FS2; b. The outlet of the deacidification fluid flow FS3; c. Inlet of absorbent stream A1; d. The inlet of the regenerated absorbent stream A3; and e. The outlet of the loaded absorbent stream A2; b) A regenerator, which has a. Inlet of the loaded absorbent stream A2; b. The outlet of the regenerated absorbent stream A3; c. The outlet of the acidic gas stream GS; c) Heat pump HP1, which includes a. Heat exchanger HE1, which has - The first inlet of flow HS1 and the outlet of flow HS2; as well as - The second inlet of heat transfer medium flow HTMS1 and the second outlet of heat transfer medium flow HTMS2; b. One or more compressors connected in series, wherein the inlet of the first compressor is connected to the second outlet of the heat transfer medium flow HTMS2 from the heat exchanger HE1, and the outlet of the last compressor in the series has the outlet of the compressed heat transfer medium flow HTMS3. d) Heat pump HP2, which is connected in series with heat pump HP1 via heat exchanger HE2, the heat exchanger having a first inlet of heat transfer medium flow HTMS3 and an outlet of heat transfer medium flow HTMS4, a second inlet of second heat transfer medium flow SHTMS1 and a second outlet of second heat transfer medium flow SHTMS2, and wherein heat pump HP2 additionally includes; a. One or more compressors connected in series, wherein the inlet of the first compressor is connected to the second outlet of the heat transfer medium flow SHTMS2 from the heat exchanger HE2, and the outlet of the last compressor in the series has the outlet of the compressed heat transfer medium flow SHTMS3. b. Heat exchanger HE-R c. It has an inlet for the second heat transfer medium flow SHTMS3 and an outlet for the second heat transfer material flow SHTMS4. The heat exchanger HE-R has an inlet connected to the absorbent stream AS1 of the regenerator and an outlet connected to the absorbent stream AS2 of the regenerator.

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