Method and apparatus for the manufacture of a treated gas with reduced solvent losses

Abstract

This invention relates to a method for producing a deacidified fluid stream comprising condensers connected to or integrated to the absorber having a low pressure loss. In a second aspect, the invention relates to an apparatus for producing a deacidified fluid stream comprising one or more condensers connected to or integrated to the absorber having a low pressure loss. In a third aspect, the invention relates to the use of condensers having a low pressure loss to reduce amine emissions in amine gas treating.

Description

[0001] Method and Apparatus for the Manufacture of a Treated Gas with Reduced Solvent Losses

[0002] This invention relates to a method for producing a treated fluid stream in an absorber comprising at least one condenser having a low pressure loss. The invention also relates to an apparatus for treating a fluid stream comprising at least one condenser having a low pressure loss. This invention further relates to the use of conders having a low pressure loss in the absorber of an acid gas removal unit.

[0003] Amine gas treating of flue gases is a proven and readily available method of reducing CO2- emissions from fossil fuel fired power plants and other CC>2-emitting sources, such as cement production, the commercial production of ore or fermentation of biomass.

[0004] Amine gas treating is also an established method for removal of H2S from the off gas of a Claus Process in which sulfur compounds, such as CS2, SO2 and COS, have been reduced to H2S. The removal of H2S from the off gas of a Claus Process is also known as tail gas treatment (TGT).

[0005] In amine gas treating, loss of the amine solvent, used as an absorbent for CO2, can occur due to the degradation of solvent to more volatile components as well as by physical phenomena of evaporation, liquid entrainment and mist formation. Accordingly, if no appropriate measures are taken to reduce amine emissions, amine losses in gas treating could constitute an undesired source of emissions and an undesired increase of the operational costs, due to the necessity to refill lost solvent.

[0006] Accordingly, many measures aimed at reducing the overall amine emissions in carbon capture have been studied (for an overview, see for example T. Spietz et al-. CH EM IK 2015. 69. 625- 634, or the SINTEF Report on “Emission Reducing Technologies” from Kolderup et al, ISBN 9788214059240 or P. Moser et aL, Demonstrating Emission Reduction - Results from the Postcombustion Capture Pilot Plant at Niederaussem”, in Energy Procedia 63 (2014) 902-910).

[0007] The most established measure for reducing amine emissions is the so-called “water wash”. The water wash is usually a section of the absorber column or a separate column where amine comprising gases are washed with water. The amines are usually removed by collecting the amine enriched water in a collecting tray and returning a part to the rich amine solvent stream leaving the absorber bottoms. The other part of the collected wash water is preferably cooled and recycled to the top of the wash section. To compensate the bleed to the rich amine solvent stream, make-up water is usually added to the recycling circuit to maintain the water balance and to avoid the build-up of a high amine concentration in the wash water. However, the amount of water which can be bled to the rich amine solvent stream is limited because otherwise the amine concentration of the rich amine stream could be changed. Accordingly, only a small amount of amine enriched water is bled off and make-up water in the same amount is added to maintain the balance. This has the practical effect that the amine concentration in the circulating water stream is nearly the same at the top and the bottom of the water wash section. Accordingly, the driving force for amine absorption in the water wash section becomes low. It is therefore preferred and sometimes even necessary to use more than one water wash section to effectively reduce amine emissions.

[0008] For more volatile amine degradation products, the water wash is often modified by the addition of acid components to the wash water to implement the so-called “acid wash”. The acidic solution can be composed of several types of acid, depending on the specific impurities targeted for removal. Examples of acids that may be used in acid water wash in carbon capture are hydrochloric acid (HCI), sulfuric acid (H2SO4), formic acid (CHOOH) or acetic acid (CH3COOH). Also carbonated condensate from the condenser of the regenerator can be used as acidic wash water. The choice of acid used in acid water wash can depend on various factors such as the type and concentration of impurities in the amine solvent, the compatibility of the acid with the materials used in the carbon capture system, and the regulatory requirements for the discharge of effluent. To avoid contamination of the amine solvent with acids, it must be ensured that the acid wash water is not bled to the bottom parts of the absorber but collected and regenerated in a separate system. Amine enriched acid wash water is usually regenerated in a reclaimer, either a thermal reclaimer or an ion exchanger, or by membrane separation.

[0009] A further development of the water wash is the so-called dry bed, which is disclosed in EP2691163. The term “dry bed” is usually used to is describe a section of the absorber beneath the water wash, where only a very low drain of water from the water wash section at the absorber top is wetting this bed. Nevertheless, this counter current multistage device is described to reduce the concentration of the solvent components in the gaseous phase (see P. Moser et aL, Demonstrating Emission Reduction - Results from the Post-combustion Capture Pilot Plant at Niederaussem”, in Energy Procedia 63 (2014) 902-910.) Another important effect for the emission mitigation is the slight temperature reduction of the flue gas, particles and droplets in the dry bed. Due to the saturation or oversaturation, water instead of organic compounds will condense on the particles and droplets in the water wash section downstream. Even though the growing droplets will not be removed from the flue gas flow by inertial separation, it is reported that entrainment of organic compounds is nevertheless reduced by an order of magnitude in the dry bed.

[0010] Demisters are gas / liquid separators used for capturing and separation droplet from a gas stream and are also used to reduce amine emissions. Preferred demisters used in amine gas treating are knit-mesh type demisters, vane type mist eliminators, and filter bed demisters, such as impaction candles. Demisters may be placed in different sections of the absorber, preferably the top, or constitute a separate piece of equipment downstream of the exhaust gas outlet of the absorber.

[0011] Other technologies used for the reduction of amine emissions are combinations of acid wash and UV treatment, electrostatic precipitators, photochemical, electrochemical and ozone-based technologies, adsorption, membranes, condensation and cold plasma processes (for an overview see SINTEF Report on “Emission Reducing Technologies” from Kolderup et al, ISBN 9788214059240). Although several technical solutions exist to reduce amine emissions in amine gas treating, there is a continuous need to provide new technological solutions which may be advantageous compared to existing technology in specific absorber set ups and geometries with respect to performance and investment costs.

[0012] Within the frame of the present invention, it was discovered that using condensers downstream of the absorber sections of the absorber and which have a low pressure drop can be employed to reduce amine emissions in amine gas treatment applications while avoiding problems associated with existing technology solutions. The use of condensers with a low pressure drop may lead to a reduction of overall amine emissions while avoiding the investment and energy downsides. For example, the use of condensers having a low pressure drop was found to overcome the problem of a high energy consumption compared to technologies having a higher pressure drop typically lying in the range of 70 to 300 mbar. To overcome a pressure drop of this magnitude it would be necessary to increase the performance of the blowers used to transport the acid gas to and from the absorber or it may even require addition blowers upstream and downstream of the absorber. This does not only increase investments costs but also results in a significant increase of the energy requirements, as the blowers constitute relatively large pieces of equipment with a high energy demand. According to estimates, the energy of the blower required to overcome a typical pressure drop of 100 mbar induced by conventional equipment could constitute up to 10% of the total energy demand of an acid gas removal unit.

[0013] Further, it has been found that a condenser with a low pressure drop can contribute to the reduction of mist and droplets from the exhaust gas stream as the mist and droplets condense to larger droplets which can be removed in a downstream demister.

[0014] Condensers having a low pressure drop can also be used as an addition to conventional technologies, such as a water wash or dry bed, to further reduce amine emissions. It has also been found that condensers having a low pressure drop may even be used to replace conventional technologies such as the dry bed and / or a water wash. Typical combinations, which have been proven useful and which are further described below, are a combination of a dry bed with a condenser having a low pressure drop or the combination of a water wash and a condenser having a low pressure drop. A particular useful embodiment of the present invention comprises more than one partial condensation steps, such as 2 to 5, preferably 2 to 4 or more preferably 2 to 3 partial condensation steps, conducted in one or more condensers having a low pressure drop. In such an embodiment, conventional technologies, such as the water wash and the dry bed, may be entirely substituted. Accordingly, the use of condensers with a low pressure drop may result in a reduction of amine emissions and a reduction of investments costs in acid gas treatment.

[0015] Accordingly, the first aspect of the present invention is therefore directed to a method for manufacture of a treated fluid stream comprising: a) an absorption step in which a fluid stream FS1 is contacted with an absorbent A1 comprising one or more amines in an absorber A to obtain an absorbent A2 laden with acid gases and an at least partly deacidified fluid stream FS2; b) a regeneration step in which at least a portion of the laden absorbent A2 obtained from step b) is regenerated in a regenerator R obtain an at least partly regenerated absorbent A3 and a gaseous stream GS comprising least one acid gas; c) a recycling step in which at least a sub stream of the regenerated absorbent A3 from step c) is recycled into the absorption step a); and wherein the method comprises an additional condensation step d), in which the partially deacidified fluid stream FS2 obtained at the top of the absorber is subjected to one or more partial condensation steps in which the fluid stream FS2 is cooled in each of the one or more condensation steps with a cooling medium CM and the pressure loss over condensation step d) is 50 mbar or less.

[0016] A second aspect of the invention is directed to an apparatus useful for reducing amine emissions in amine gas treating comprising: a) an absorber with a. an inlet for fluid stream FS1 , b. an outlet for a deacidified fluid stream FS2; c. an inlet for an absorbent stream A1 and / or an inlet for regenerated absorbent stream A3; and d. an outlet for a laden absorbent stream A2 b) a regenerator with a. an inlet for laden absorbent stream A2; b. an outlet for regenerated absorbent stream A3; c. an outlet for an acid gas stream GS; and c) one or more condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2 and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the one or more condensers and the outlet for fluid stream FS2 of the last of the one or more condensers is 50 mbar or less.

[0017] A third aspect of the present invention is directed to the use of condensers which are designed in such a manner that the pressure-drop between the entrance of the condenser and the exit of the condenser is 50 mbar or less as further specified in claims 11 to 14.

[0018] 1staspect- Method for Producing a Deacidified Fluid Stream

[0019] The method according to the first aspect of the invention comprises: a) an absorption step in which a fluid stream FS1 is contacted with an absorbent A1 comprising one or more amines in an absorber A to obtain an absorbent A2 laden with acid gases and an at least partly deacidified fluid stream FS2; b) a regeneration step in which at least a portion of the laden absorbent A2 obtained from step b) is regenerated in a regenerator R obtain an at least partly regenerated absorbent A3 and a gaseous stream GS comprising at least one acid gas; and a c) a recycling step in which at least a sub stream of the regenerated absorbent A3 from step c) is recycled into the absorption step a).

[0020] According to the present invention, fluid stream FS1 is deacidified in an absorption step a) in which fluid stream FS1 is contacted with an absorbent A1 comprising one or more amines in an absorber A to obtain an absorbent A2 laden with acid gases and an at least partly deacidified fluid stream FS2.

[0021] The fluid stream FS1 entering the absorber in step a) may be any fluid stream comprising at least one acid gas.

[0022] Preferably the preferably the fluid stream FS1 comprises CO2. In addition to CO2, other acid gases, such as H2S, CS2 or COS may be present. In addition, oxides of sulfur and nitrogen SOXand NOXmay be present.

[0023] The content of acid gases in the fluid stream FS1 is generally 0.01 % to 50% by volume, preferably 2% to 30% by volume and more preferably 3% to 25% by volume.

[0024] The fluid stream FS1 may comprise water. The water content in the fluid stream is generally within a range from > 0% by volume up to a content corresponding to the saturation concentration of water in the fluid stream under the existing pressure and temperature conditions.

[0025] The pressure of fluid stream FS1 usually depends on the source of the fluid stream FS1 as further outlined below. But in a preferred embodiment of the present invention, the pressure of the fluid stream FS1 is 5 bar or less, more preferably 4 bar or less, even more preferably 3 bar or less and most preferably 2 bar or less. Preferably the pressure of fluid stream FS1 is at or around atmospheric pressure. In the aforementioned pressure ranges, the process of the present invention is particularly effective.

[0026] Preferably, the fluid stream 1 is a flue gas.

[0027] Flue gases are preferably obtained by combustion of carbon-based fuels, such as fossil fuels like coal, natural gas and oil, or biomass feedstocks from plants, algae or animals.

[0028] Such combustion processes can occur in power plants or power stations. Preferably, the source of the flue gas is from combustion of coal, natural gas, oil, biofuels, such as bioethanol or biodiesel, or biomass derived from forestry, agriculture or aquaculture.

[0029] Preferably, fluid stream FS1 is a flue gas exiting the steam turbine of a steam-electric power stations in which the generator is driven by steam obtained from the combustion of carbonbased fuels.

[0030] Most preferably, fluid stream FS1 is a flue gas exiting the steam turbine of a gas-fired power plant which is designed as a simple cycle gas-turbine or a combined cycle power plant.

[0031] Prior to being used in the method of the present invention, the flue gas stream FS1 is optionally treated to remove particulate matter by filtration or electrostatic precipitation. In a preferred embodiment, the flue gas stream FS1 is desulfurized by removing sulfur dioxide. An overview of flue-gas desulfurization methods can be found in the Wikipedia article “Flue-gas

[0032] Fluid flue gas stream FS1 preferably comprises:

[0033] CO2: 1 to 25 vol.%, preferably 5 to 20 vol.-%;

[0034] H2O: 3 to 50 vol.%, preferably 5 to 30 vol.-%; and

[0035] O2: 0.1 to 16 vol.%, preferably 1 to 10 vol.-%,

[0036] Additionally, flue gases comprise small amounts of other gases, in particularly nitrogen oxides (NOx) and sulfur oxides (SOx), even after a flue gas desulfurization step.

[0037] Flue gas also comprises nitrogen in an amount so that sum of the volume fractions of each component present in the flue gas add up to a value of 1 (or 100 vol.-%). Typically, the nitrogen content is in the range of 40 to 95 vol.%.

[0038] Fluid stream FS1 is preferably in the gaseous state. Depending on the temperature and the water content, fluid stream FS1 may also comprise condensed water and acids.

[0039] When the fluid stream is a flue gas, the pressure of the fluid stream FS1 entering the cooling step is usually at atmospheric pressure, preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1 .3 bar and more preferably 0.9 to 1 .2 bar.

[0040] The temperature of fluid flue gas stream FS 1 is preferably in the range of 5 to 100°C, preferably 10 to 60°C and most preferably 20 to 45°C.

[0041] Fluid stream FS1 may also be an off-gas stream in which CO2 is emitted in an industrial process which liberates CO2 from a chemical reaction. Such industrial process streams include CO2- emissions from the thermal decomposition of limestone and dolomite in the production of cement, CC>2-emissions from using carbon as a reducing agent in the commercial production of metals from ores (e.g. the production of iron in a blast furnace), or CC>2-emissions from the fermentation of biomass (e.g. to convert sugar to alcohol) or the decomposition of biomass in landfills (landfill gas).

[0042] In a preferred embodiment, fluid stream FS1 is stream which combines flue gas from a carbon- fuel combustion process with CC>2-emissions from a CC>2-producing industrial process, such as cement production, metal production or fermentation or decomposition processes.

[0043] In a further preferred embodiment, fluid stream FS1 is a flue gas stream coming from a furnace of a cracker, in which hydrocarbons, such as petroleum fractions, naphtha, natural gas liquids, such methane, ethane and propane, are thermically or catalytically cracked to obtain shorter chain molecules or recombined molecules having a different structure. Preferably, the fluid stream FS1 is the flue gas of a steam cracker furnace.

[0044] Fluid stream FS1 can also preferably be the off gas or tail gas of a Claus Process in which sulfur compounds, such as CS2, SO2 and COS, have been reduced to H2S. Such streams usually comprise 0.5 to 10 vol.-% H2S and around 1 to 50 vol-% CO2.

[0045] The pressure of fluid stream FS1 is preferably in the range of 0.7 to 5 bar, more preferably 0.8 to 3 bar and more preferably 0.9 to 1 .5 bar when fluid stream FS1 is a so-called tail gas from a Claus Process. Preferably, the pressure fluid stream FS1 is at or around atmospheric pressure when fluid stream FS1 is a tail gas from a Claus Process. The absorbent A1 used in absorber A comprises one or more amines.

[0046] The following amines are preferred: i) amines of the formula I:

[0047] NR1(R2)2(I) in which R1is selected from C2-C6-hydroxyalkyl groups, Ci-C6-alkoxy-C2-Ce-alkyl groups, hy- droxy-Ci-C6-alkoxy-C2-C6-alkyl groups and 1-piperazinyl-C2-C6-alkyl groups, and R2is independently selected from H, Ci-C6-alkyl groups and C2-C6-hydroxyalkyl groups; ii) amines of the formula 11 :

[0048] R3R4N-X-NR5R6(II) in which R3, R4, R5and R6are independently selected from H, Ci-Ce-alkyl groups, C2-Ce-hydrox- yalkyl groups, Ci-C6-alkoxy-C2-Ce-alkyl groups and C2-Ce-aminoalkyl groups, and X is a C2-C6- alkylene group, -X1-NR7-X2- or -X1-O-X2-, in which X1and X2are independently C2-C6-alkylene groups and R7is H, a Ci-C6-alkyl group, C2-C6-hydroxyalkyl group or C2-C6-aminoalkyl group; iii) 5- to 7-membered saturated heterocycles which have at least one nitrogen atom in the ring and may comprise one or two further heteroatoms selected from nitrogen and oxygen in the ring, and iv) mixtures thereof.

[0049] Specific examples of amines usable with preference are: 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, t-butylaminoethoxyethanol (TBAEE), 2- amino-2-methylpropanol, diisoproanolamine (DIPA); ii) 3-methylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, 2,2-dimethyl-1 ,3-diaminopropane, hexamethylenediamine, 1 ,4-diaminobutane, 3,3-iminobis- propylamine, tris(2-aminoethyl)amine, bis(3-dimethylaminopropyl)amine, tetramethyl hexamethylenediamine; iii) piperazine, 2-methylpiperazine, N-methylpiperazine, 1 -hydroxyethylpiperazine, 1 ,4- bishydroxyethylpiperazine, 4-hydroxyethylpiperidine, homopiperazine, piperidine, 2-hydroxyeth- ylpiperidine, triethylendiamine (TEDA) and morpholine; and iv) mixtures thereof. In a preferred embodiment, the absorbent comprises at least one of the amines monoethanolamine (MEA), methylaminopropylamine (MAPA), piperazine (PIP), diethanolamine (DEA), triethanolamine (TEA), diethylethanolamine (DEEA), diisopropanolamine (DI PA), aminoethoxyethanol (AEE), tert-butylaminoethoxyethanol (TBAEE), dimethylaminopropanol (DI MAP) and methyldiethanolamine (MDEA), triethylendiamine (TEDA) or mixtures thereof.

[0050] Further amines that may be introduced into the process are tert-butylaminopropanediol, tert-bu- tylaminoethoxyethylmorpholine, tert-butylaminoethylmorpholine, methoxyethoxyethoxyethyl-tert- butylamine, tert-butylaminoethylpyrrolidone.

[0051] The amine is preferably a sterically hindered amine or a tertiary amine. A sterically hindered amine is a secondary amine in which the amine nitrogen is bonded to at least one secondary carbon atom and / or at least one tertiary carbon atom; or a primary amine in which the amine nitrogen is bonded to a tertiary carbon atom. A preferred sterically hindered amine is t-butylami- noethoxyethanol. A preferred tertiary amine is methyldiethanolamine and triethylendiamine (TEDA).

[0052] If the aim is to remove the CO2 present in the fluid stream completely or virtually completely, the absorbent preferably additionally comprises an activator when the amine present in the absorbent is a sterically hindered amine or a tertiary amine. The activator is generally a sterically unhindered primary or secondary amine. In these sterically unhindered amines, the amine nitrogen of at least one amino group is bonded only to primary carbon atoms and hydrogen atoms. If the aim is merely to remove a portion of the gases present in the fluid stream, for example the selective removal of H2S from a fluid stream comprising H2S and CO2, the absorbent preferably does not comprise any activator.

[0053] The sterically unhindered primary or secondary amine which can be used as activator is selected, for example, from alkanolamines, such as monoethanolamine (MEA), diethanolamine (DEA), ethylaminoethanol, 1-amino-2-methyl-propan-2-ol, 2-amino-1-butanol, 2-(2-aminoeth- oxy)ethanol and 2-(2-aminoethoxy)ethanamine, polyamines, such as hexamethylenediamine, 1 ,4-diaminobutane, 1 ,3-diaminopropane, 3-(methylamino)propylamine (MAPA), N-(2-hydroxy- ethyl)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 comprise one or two further heteroatoms selected from nitrogen and oxygen in the ring, such as piperazine, 2-methylpiperazine, N-methylpipera- zine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-aminoethyl)piperazine, homopiperazine, piperidine and morpholine.

[0054] Particular preference is given to 5-, 6- or 7-membered saturated heterocycles which have at least one NH group in the ring and may comprise one or two further heteroatoms selected from nitrogen and oxygen in the ring. Very particular preference is given to piperazine.

[0055] The molar ratio of activator to sterically hindered amine or tertiary amine is preferably in the range from 0.05 to 1.0, more preferably in the range from 0.05 to 0.7.

[0056] The absorbent generally comprises 10% to 60% by weight of amine.

[0057] In one embodiment, the absorbent comprises the tertiary amine methyldiethanolamine and the activator piperazine.

[0058] In a preferred embodiment, the absorbent comprises A) at least one cyclic amine compound having solely tertiary amine groups and

[0059] B) at least one cyclic amine compound having at least one sterically unhindered secondary amine group, wherein the total concentration of A) + B) is 10 to 60% by weight.

[0060] Such absorbents are disclosed in EP2391435. Most preferably amine A) is triethylendiamine (TEDA) and activator amine B) is piperazine.

[0061] The absorbent may additionally comprise physical solvents. Suitable physical solvents are, for example, N-methylpyrrolidone, tetramethylenesulfone, oligoethylene glycol dialkyl ethers such as oligoethylene glycol methyl isopropyl ether (SEPASOLV MPE), oligoethylene glycol dimethyl ether (SELEXOL). The physical solvent is generally present in the absorbent in amounts of 1 % to 60% by weight, preferably 10% to 50% by weight, especially 20% to 40% by weight.

[0062] In a preferred embodiment, the absorbent comprises less than 10% by weight, for example less than 5% by weight, in particular less than 2% by weight of inorganic basic salts, such as potassium carbonate for example.

[0063] The absorbent may also comprise additives, such as corrosion inhibitors, antioxidants, enzymes, antifoams etc. In general, the amount of such additives is in the range of about 0.01-3% by weight of the absorbent.

[0064] The absorber may be supplied with fresh absorbent, or the absorber may be supplied with absorbent regenerated in the recycling step c). The supply of fresh absorbent means that the components of the absorbent are yet to pass through steps b) to d). The supply of regenerated absorbent requires at least a portion of the components of the absorbent to have passed through steps b) to d).

[0065] The absorbent is preferably aqueous. This means that the wide variety of different constituents of the absorbent, such as amine, methanol, physical solvents, additives, may be mixed with water in the amounts mentioned above.

[0066] The fluid stream FS1 is preferably contacted with the absorbent in step a) in an absorber A.

[0067] The absorber is preferably an absorption tower or an absorption column, for example a column with random packing or structured packing.

[0068] The absorber generally comprises an absorption zone and optionally a rescrubbing zone.

[0069] The absorption zone is deemed to be the section of the absorption column in which the fluid stream comes into mass transfer contact with the absorbent.

[0070] The fluid stream is preferably contacted in countercurrent with the absorbent in the absorption zone.

[0071] To improve contact with the absorbent and provide a large mass transfer interface, the absorption zone generally comprises internals, for example random packings, structured packings and / or trays, such as valve trays, bubble-cap trays, Thormann trays or sieve trays.

[0072] If the absorption zone comprises random packings or structured packings, the height of the random packings / structured packings of the absorption zone is preferably in the range from 5 to 20 m, more preferably in the range from 6 to 15 m and most preferably in the range from 8 to 14 m. If the absorption zone comprises trays, the number of trays in the absorption zone is preferably in the range from 8 to 30, more preferably 12 to 25 and most preferably 15 to 23 trays.

[0073] In the case of columns with random packings or structured packings, the absorption zone may be divided into one or more sections, preferably 2 to 4 sections. Bearing and holding trays and / or distributor trays may be disposed between the individual sections of the absorption zone, and these improve the distribution of the absorbent over the entire cross section of the column. In a preferred embodiment, the absorber comprises structured packings to improve the contact between fluid stream FS1 and the absorbent in the absorption zone. Structured packings usually have a significantly lower pressure loss than trays and the overall pressure drop in the absorber can be kept low by combining a condenser with a low pressure drop with structured packings.

[0074] The temperature of the absorbent introduced into the absorption zone is generally about 0 to 90°C, preferably 10 to 60°C and more preferably 25 to 50°C.

[0075] The pressure in the absorber depends on the pressure and the type of fluid stream FS1 entering the absorber.

[0076] When fluid stream FS1 is a flue gas, the pressure in the absorber is preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1.3 bar and more preferably 0.9 to 1.2 bar.

[0077] When fluid stream FS1 is a tail gas from a Claus Process, the pressure in the absorber is preferably in the range of 0.7 to 5 bar, more preferably 0.8 to 3 bar and more preferably 0.9 to 1.5 bar. Most preferably, the absorber is operated at about atmospheric pressure, when fluid stream F12 is a flue gas or a hydrogen sulfide comprising tail gas from a Claus Process.

[0078] The feed point for the fluid stream introduced is preferably below or in the lower region of the absorption zone. The feed is preferably evenly distributed over the cross-section of the absorber via a gas distributor.

[0079] The absorber may comprise one or more feed points for the absorbent introduced. For instance, the absorber may comprise a feed point for fresh absorbent A1 and a feed point for regenerated absorbent A3. Fresh and regenerated absorbent may alternatively be fed into the absorber together via one feed point. The one or more feed points are preferably above or in the upper region of the absorption zone. It is also possible to feed in individual constituents of the absorbent, such as make-up water, via the feed point for fresh absorbent.

[0080] If the absorber has an optional rescrubbing zone, the feed is preferably between the absorber zone and the rescrubbing zone.

[0081] The contacting of the fluid stream with the absorbent in the absorption zone affords an at least partly deacidified fluid stream FS2 and an absorbent A2 laden with acid gases.

[0082] There is generally a draw point for the laden absorbent A2 in the lower region of the absorber, preferably at the bottom.

[0083] In a preferred embodiment, the at least partly deacidified fluid stream FS2 is contacted with a scrubbing liquid in one or more rescrubbing zones (collectively referred to as “rescrubbing zone” or “wash section”).

[0084] The scrubbing liquid is more preferably an aqueous liquid. The scrubbing liquid may be a liquid intrinsic to the process, i.e. , an aqueous liquid obtained elsewhere in the process, or aqueous liquids supplied from the outside. Preferably, the scrubbing liquid comprises a condensate (called absorber top condensate) formed in a downstream cooling operation on the deacidified fluid stream and / or fresh water. Most preferably, the scrubbing liquid is water. The scrubbing liquid can also be an acidic aqueous solution with a pH in the range if 2 to less than 7, more preferably 3 to 6.5 and most preferably 3 to 5. Usually, an acid scrubbing liquid can be obtained by dissolving a corresponding acid or acidic oxide. Preferably, the scrubbing liquid is an aqueous solution of an inorganic acid, preferably sulfuric acid or hydrochloric formic acid, or an organic acid, preferably formic, oxalic or acetic acid. Details for the implementation of an acid wash can be found in the SINTEF Report on “Emission Reducing Technologies” from Kolderup et al, ISBN 9788214059240.

[0085] The rescrubbing zone is generally a section of the absorber above the feed point of the absorbent.

[0086] The rescrubbing zone preferably has random packings, structured packings and / or trays to intensify the contact between the fluid stream and the scrubbing liquid.

[0087] The rescrubbing zone comprises preferably 1 to 7, more preferably 2 to 6 and most preferably 3 to 5 trays, or a packing height (random packings / structured packings) of preferably 1 to 6 m, more preferably 2 to 5 and most preferably 2 to 3 m.

[0088] In a preferred embodiment, the rescrubbing zone comprises structured packings to improve the contact between fluid stream FS1 and the absorbent in the absorption zone. Structured packings usually have a significantly lower pressure loss than trays and the overall pressure drop in the absorber can be kept low by combining a condenser with a low pressure drop with structured packings.

[0089] The scrubbing liquid is generally introduced above the rescrubbing zone or into the upper region of the rescrubbing zone. The scrubbing liquids used may be the abovementioned scrubbing liquids.

[0090] The scrubbing liquid is preferably recycled via the rescrubbing zone. This is achieved by collecting the scrubbing liquid below the rescrubbing zone, for example by means of a suitable collection tray, and pumping it to the upper end of the rescrubbing zone by means of a pump. The recycled scrubbing liquid may be cooled, preferably to a temperature of from 20°C to 70°C, in particular 30°C to 60°C. This is advantageously achieved by recirculating the scrubbing liquid through a cooler. In order to avoid any accumulation of scrubbed-out absorbent constituents in the scrubbing liquid, a sub stream of the scrubbing liquid is preferably discharged from the rescrubbing zone.

[0091] By the contacting of the at least partly deacidified fluid stream FS2 with a scrubbing liquid in a rescrubbing section or wash section, it is possible to scrub out entrained absorbent constituents, such as amines thereby further minimizing amine emissions. The contacting with an aqueous scrubbing liquid can additionally improve the water balance of the process when more water is discharged via the exiting streams than is introduced via the entering streams.

[0092] In a more preferred embodiment, the absorber also comprises a so-called dry bed, which is disclosed in more detail in EP2691163. The term “dry bed” is usually used to is describe a section of the absorber beneath the water wash, where only a very low drain of water from the water wash section at the absorber top is wetting this bed. Nevertheless, this counter current multistage device is described to reduce the concentration of the solvent components in the gaseous phase. Another important effect for the emission mitigation is the slight temperature reduction of the flue gas, particles and droplets in the dry bed. Due to the saturation or oversaturation, water instead of organic compounds will condense on the particles and droplets in the water wash section downstream. Even though the growing droplets will not be removed from the flue gas flow by inertial separation, on the following flue gas path entrainment of organic compounds is reduced by an order of magnitude.

[0093] A deacidified fluid stream FS2, as described above, is preferably drawn off via a draw point in the upper part of the absorber and fed to step d) as further described below. But step d) must not necessarily be conducted in a separate piece of equipment but may alternatively also be integrated in the absorber itself, preferably the top part absorber.

[0094] Step a) affords an absorbent A2 at least partially laden with acid gases.

[0095] The laden absorbent A2 may be fed directly to the regeneration step b).

[0096] In a particular embodiment of the process of the invention, an expansion step is first conducted on the laden absorbent A2 before it is introduced into the regeneration step b).

[0097] In the expansion step, the laden adsorbent A2 is generally guided into one or more expansion vessels where the laden absorbent A2 is expanded through a throttle valve into the expansion vessel.

[0098] The expansion generally leads to the desorption the so-called flash gas. The flash gas may be guided back into the absorption by means of a compressor or incinerated for energy generation or flared off in situ.

[0099] If the fluid stream FS1 is a flue gas, the laden absorbent is preferably pumped to an expansion vessel which is located downstream of a crossflow heat exchanger HE-CF. In this case. In this case, the pump usually increases the pressure of the fluid stream FS1 by approximately 2 to 8 barg so it can be expanded to an expansion vessel which is preferably operating slightly above the pressure of the regenerator. The effect of the expansion step is usually enhanced by the temperature increase of the fluid stream FS1 when passing the crossflow heat exchanger HE- CF. The performance of an additional expansion step has the advantage that at least part of the oxygen comprised in fluid stream FS1 may be flashed-off which has a negative impact on the required purity of CO2.

[0100] The flash vessel is generally a vessel free of any particular internals. The flash vessel is preferably a flash drum. Alternative flash vessels include columns having internals, for example random packings, structured packings, or trays.

[0101] In the upper region of the flash vessel, there is generally a gas draw for the gases converted to the gas phase. A demister may preferably be disposed in turn in the region of the gas draw. If required, the acid gases present may be separated from the flash gas in a further absorption column. Typically, for this purpose, a sub stream of the regenerated solvent is supplied to the additional absorption column. At the base of the flash vessel, in general, the absorbent A2 at least partly laden with the acid gases that have not been converted to the gas phase is drawn off and is generally guided into regeneration step b).

[0102] According to the invention, the adsorbent at least partly laden with acid gases A2 is fed into the regeneration step b), in which at least a portion of the laden absorbent A2 obtained from step a) is regenerated in a regenerator to obtain an at least partly regenerated absorbent A3 and a gaseous stream GS comprising at least one acid gas.

[0103] The gaseous stream GS may comprise residual amounts of water which have not been separated off in the rescrubbing zone.

[0104] Before being introduced into the regeneration step b), the adsorbent A2 at least partly laden with acid gases is preferably guided through a crossflow heat exchanger HE-CF.

[0105] In the crossflow heat exchanger HE-CF, the absorbent A2 at least partly laden with acid gases is preferably heated to a temperature in the range from 50 to 150°C, more preferably 70 to 130°C and most preferably 80 to 110°C. In a particular embodiment, the regenerated absorbent A3 drawn from the bottom of the regenerator is used as heating medium in the heat exchanger HE-CF. This embodiment has the advantage that the thermal energy of the regenerated absorbent A3 from stage b) can be used to heat the laden absorbent A2 from step a) in heat exchanger HE-CF. In this way, it is possible to reduce the energy costs of the overall process and to reduce the energy requirement in the reboiler of regeneration step b).

[0106] According to the invention, the regeneration step is conducted in a regenerator R.

[0107] The regenerator is generally configured as a stripping column.

[0108] The regenerator preferably comprises a regeneration zone and a reboiler.

[0109] The regenerator is preferably operated at a top pressure in the range from 0.5 to 5 bar, preferably 0.7 to 4 and more preferably 0.9 to 2.5 bar.

[0110] In the bottom of the regenerator, there is generally disposed a liquid draw for the regenerated absorbent A3.

[0111] At the top of the regenerator, there is generally a gas draw for the gaseous stream GS. A demister is preferably mounted in the region of the gas draw.

[0112] The regenerator generally has a regeneration zone disposed above the bottom and below the rescrubbing zone. In the present context, the regeneration zone is regarded as the region of the regenerator with which the laden absorbent comes into contact with the steam which is produced in the reboiler.

[0113] To improve contact and provide a large mass transfer interface, the regeneration zone generally comprises internals, for example random packings, structured packings and / or trays, such as valve trays, bubble-cap trays, Thormann trays or sieve trays.

[0114] If the regeneration zone comprises structured packings or random packings, the height of the structured packings / random packings in the regeneration zone is preferably in the range from 5 to 15 m, more preferably in the range from 6 to 12 m and most preferably in the range from 8 to 12 m.

[0115] If the regeneration zone comprises trays, the number of trays in the regeneration zone is preferably in the range from 10 to 30, more preferably 15 to 25 and most preferably 17 to 23 trays. In the case of columns with random packings or structured packings, the regeneration zone may in turn be divided into multiple sections, preferably 2 to 4. Bearing and holding trays and / or distributor trays may be disposed between the sections of the regeneration zone, and these improve the distribution of liquid over the entire cross section of the regenerator.

[0116] In general, the laden absorbent A2 is preferably introduced into the regenerator in the upper region or above the regeneration zone and below the rescrubbing zone.

[0117] In the regeneration zone, the vapor generated in the evaporator is generally operated in countercurrent to the absorbent flowing downward through the regeneration zone.

[0118] The zone of the regenerator beneath the regeneration zone is generally referred to as the bottom.

[0119] In this region, the absorbent is typically collected and (i) fed as absorbent stream AS1 to the reboiler HE-R via pipelines via a liquid draw in the lower region of the regenerator, and / or (ii) partly recycled into the absorber as regenerated absorbent A3.

[0120] The bottom may be divided by a collecting tray disposed between the bottom draw and the feed point for the steam produced in the evaporator.

[0121] In general, at least a portion of the regenerated absorbent A3 is guided from the bottom draw of the regenerator into the reboiler as absorbent stream AS1 .

[0122] Preferably, the bottom draw from the regenerator is guided completely into the reboiler as absorbent stream AS1.

[0123] The reboiler HE-R is typically a kettle type reboiler, natural circulation reboiler or thermosiphon reboiler or a forced circulation reboiler.

[0124] The reboiler HE-R of the regenerator is preferably disposed outside the regenerator and connected to the bottom draw via pipelines.

[0125] The reboiler HE-R is generally operated at temperatures in the range from 100 to 150°C, preferably 105 to 140°C and most preferably 110 to 130°C.

[0126] In the reboiler HE-R, in general, at least a portion of the bottom draw is evaporated and returned to the regenerator as absorbent stream AS2. Absorbent stream AS2 is preferably fed to the regenerator beneath the regeneration zone, preferably into the bottom of the regenerator. If an additional collecting tray is disposed in the bottom, the steam produced in the reboiler is preferably fed in beneath the collecting tray.

[0127] In a preferred embodiment, the regenerator R has a rescrubbing zone above the regeneration zone, especially preferably above the feed point for the laden absorbent A2.

[0128] The rescrubbing zone generally takes the form of a section of the regenerator disposed above the regeneration zone.

[0129] The rescrubbing zone preferably has internals, especially random packings, structured packings and / or trays to intensify the contact between the fluid stream and the scrubbing liquid. Particularly preferably, the scrubbing section has trays, especially valve trays or bubble-cap trays.

[0130] In a preferred embodiment, the internals are random packings and / or structured packings. The packing height (random packings / structured packings) is preferably within a range from 1 to 10, more preferably 2 to 8 and most preferably 3 to 6 m. In a very particularly preferred embodiment, the rescrubbing zone has trays, especially valve trays or bubble-cap trays, the number of trays preferably being in the range from 2 to 10, more preferably 2 to 8 and most preferably 2 to 6 trays.

[0131] A scrubbing liquid may be introduced into the upper region of the rescrubbing zone or above the rescrubbing zone.

[0132] The scrubbing liquid used is generally an aqueous or slightly acidic aqueous solution, especially water. The temperature of the scrubbing liquid is generally in the range from 10 to 60°C, preferably in the range from 20 to 55°C and more preferably 30 to 40°C.

[0133] In the rescrubbing zone, entrained residual amounts of amines may be scrubbed out of the absorbent, such that the acidic off gas GS leaving the regenerator is essentially free of amines. In the rescrubbing zone, the water content of the gas stream which is obtained at the top of the regenerator may additionally be reduced since the contact with the colder scrubbing agent can result in condensation of a portion of the vaporous water.

[0134] In a preferred embodiment of the present invention, the acid gas stream GS from the regenerator is introduced into a condensation step.

[0135] In the condensation step, a condensate comprising water is condensed out of the gaseous stream (condensate outlet). The uncondensed gas phase is preferably discharged to a compression step, as further described below.

[0136] The condensation step is preferably conducted in such a way that the gaseous stream GS from stage b) is guided through one or more condensers (regenerator top condensers). The top condensers generally comprise a heat exchanger and a vessel in which the liquid phase can be separated from the gas phase (phase separation vessel). However, heat exchanger and vessel may also be integrated in one component.

[0137] The regenerator top condenser is generally operated in such a way that water will condense, while the acid gases remain predominantly in the gas phase.

[0138] Regenerator top condensers used may, for example, be condensers having cooling coils or helical tubes, jacketed tube condensers and shell and tube heat exchangers.

[0139] The regenerator top condenser is generally operated at a temperature in the range from 10 to 60°C, preferably 20 to 55°C, more preferably 30 to 40°C.

[0140] In a preferred embodiment, the gaseous stream GS from stage c) is guided through one regenerator top condenser.

[0141] It is optionally possible to additionally introduce a scrubbing liquid, as described above, into the regenerator together with the condensate from the condensation step. The introduction can be effected via the same feed point. Scrubbing liquid can alternatively be introduced via a separate feed point.

[0142] Fluid stream GS preferably comprises CO2, especially if fluid stream FS1 is a flue gas.

[0143] To prevent release of such CO2 to the atmosphere, the CO2 is preferably sequestered in suitable storage locations.

[0144] Sequestration generally requires that the gaseous CO2stream GS is compressed and optionally cooled into a fluid which can be transported through pipelines to its destination, or which can be transported as a chemical to its destination where it is utilized for further uses. Typical pressures of CO2-pressures in pipelines for transportation are 70 to 200 bar, preferably 90 to 150 bar. Typical pressures of CO2for transportation by ship, truck or train are 5 to 50 bar, preferably 6 to 40 and more preferably 7 to 35 bar.

[0145] Compression is usually affected in one or more compressors. The compressor is usually configured to receive the CO2comprising gaseous stream GS and compress the gaseous stream to yield a compressed fluid stream CFS.

[0146] The compressor is typically a positive displacement compressor or a dynamic compressor. Positive displacement compressors comprise reciprocating compressors that use pistons driven by a crankshaft to deliver fluids at higher pressures. Reciprocating compressors can be single or multi-staged. Positive displacement compressors also comprise rotary screw compressors, conical screw compressors, rotary vane compressors, rolling piston compressors or scroll compressors.

[0147] The compressor can also be a dynamic compressor, such as a centrifugal compressor or an axial compressor.

[0148] Preferably, the compressor is a rotary screw compressor, a centrifugal compressor, a piston compressor, or an axial flow compressor.

[0149] After compression or after each compression step in a compressor, the fluid stream CFS is preferably passed through one or more heat exchangers to dissipate the heat from the compressed fluid or to utilize the heat of compression as a heat source for heating other processes or other steps of the gas treatment process.

[0150] Alternatively, compression may be supplemented by one or more additional refrigeration steps to liquify the CO2. CO2may be cooled in a heat exchanger which is an evaporator for a heat transfer material, preferably liquid ammonia. The evaporated heat transfer material is then compressed, cooled, and expanded in a tradition refrigeration circuit. It is also possible to combine two or more refrigeration circuits in series, which reduces the energy consumption of refrigeration.

[0151] Further, CO2may be compressed and cooled by external water and expansion to the transportation temperature and then compressed. Non-liquefied CO2is preferably separated a recirculated to the compression step. The energy consumption can be reduced by performing the compression and depressurization (evaporation) in several steps.

[0152] It is usually preferred to dry the CO2-comprising stream GS. Drying can occur before, after or after one or more of the compression steps or cooling steps.

[0153] Drying is preferably conducted in the form of a pressure swing adsorption (PSA) and more preferably in the form of a temperature swing adsorption (TSA), or in the form of a glycol drying operation.

[0154] PSA or TSA can be conducted by methods known to the person skilled in the art. Standard variant procedures are described, for example, in Nag, Ashis, “Distillation and Hydrocarbon Processing Practices”, PennWell 2016, ISBN 978-1-59370-343-1 or in A. Terrigeol, GPA Europe, Annual Conference, Berlin, Germany, 23rd-25th May, 2012 (https: / / www.cecachemi- cals.com / export / sites / ceca / .content / medias / downloads / products / dtm / molecular-sieves-contami- nants-effects-consequences-and-mitigation.pdf). In PSA or TSA, preference is given to using zeolites, activated carbon, molecular sieve or silica gels, such as Sorbead, which is an alumino-silicate gel in the form of hard, spherical beads. Preference is given to using a molecular sieve as solid adsorbent in PSA or TSA.

[0155] In the glycol drying operation, preference is given to using a liquid absorbent such as monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG) or tetraethylene glycol (TREG). TEG is especially preferably used as liquid absorbent.

[0156] The glycol drying operation can be conducted by process variants known to the person skilled in the art. Examples of glycol drying are likewise found, for example, in Nag, Ashis, "Distillation and Hydrocarbon Processing Practices", PennWell 2016, ISBN 978-1-59370-343-1.

[0157] Likewise, other components, such as carbonyl sulfide (COS) and hydrogen sulfide may be removed by installing additional filters and adsorbers.

[0158] The fluid stream CFS is preferably transported to its storage location or its final utilization. CO2 may be transported via pipelines or by a carrier, such as truck, train, and ship..

[0159] Suited storage locations are suited geological formations, such as depleted oil and gas reservoirs, mines and saline or other rock formations.

[0160] CO2may also be used by the food industry, the oil industry, and the chemical industry. Preferred uses for CO2in the food industry is the carbonization of beverages.

[0161] Other utilizations of captured carbon dioxide are enhanced oil recovery or conversion to fuel, cement, minerals, or chemicals or use as a material for fire extinguishers, as a solvent, as an inert gas or a refrigerant

[0162] According to the invention, the regenerated absorbent A3 obtained at the bottom of the regenerator from step c) is returned to the absorption step a).

[0163] The regenerated absorbent is preferably recycled in one of the feed points of the absorber for the regenerated absorbent by cooling the absorbent A3 in the cross-flow heat exchanger HE-CF and an additional cooler as described above, to achieve the feed temperature of the lean absorbent also set out above.

[0164] The method according to the first aspect of the invention also comprises an additional condensation step d), in which the partially deacidified fluid stream FS2 obtained at the top of the absorber is subjected to one or more partial condensation steps in which the fluid stream FS2 is cooled in each of the one or more partial condensation steps with a cooling medium CM and the pressure loss over condensation step d) is 50 mbar or less.

[0165] The condensation step may consist of a single partial condensation step, or it may comprise more than one partial condensation steps, preferably 2 to 5 partial condensation steps more preferably 2 to 4 partial condensation steps and most preferably 2 to 3 partial condensation steps.

[0166] The condensation step d) is a partial condensation step as only some of the components comprised in the deacidified fluid stream FS2 are condensed to the liquid state by cooling stream FS2 while the main part of fluid stream FS2 remains in a gaseous state. A partial condensation step within the meaning of the present invention comprises feeding fluid stream FS2 to the entrance of a cooling zone cooled by a cooling medium CM having a temperature TCM on the cooling medium entrance side and a temperature T’CM at the exit of the cooling medium side and withdrawing a condensate stream CS and a cooled fluid stream FS2. In subsequent partial condensation steps, the temperature TCM at the inlet of a subsequent partial condensation step is preferably lower than the temperature T’CM at the exit of the preceding partial condensation step and most preferably, the temperature TCM at the entrance of each partial condensation step is the same for all partial condensation steps. In this case, cooling medium from the same source may be used in all partial condensation steps by splitting the cooling medium into different supply streams. Conducting condensation step d) with more than one partial condensation steps has the advantage that more than one thermodynamic separation stages may be achieved resulting in a further reduction of amine emissions.

[0167] The temperature of deacidified fluid stream FS2 entering the condensation step d) is preferably in the range of 30 to 100°C, more preferably 40 to 90°C and most preferably in the range of 45 to 70°C.

[0168] During the condensation step d), the fluid stream FS2 is cooled so that the temperature of fluid stream FS2 exiting the partial condensation step d) is preferably in the range of 20 to 80°C, more preferably 25 to 60°C and most preferably 40 to 60°C.

[0169] Cooling to the preferred temperatures can be achieved by using one or more condensers having the appropriate cooling capacity. The cooling medium CM used for cooling the deacidified fluid stream FS2 in condensation step d) can be any suited cooling medium. Preferably, the cooling medium CM is water, glycol, air, a refrigerant or a thermal oil. Most preferably, the cooling medium is water. Preferably the cooling medium has a temperature TCM in the range of 0 to 50°C, more preferably 10 to 40°C and even more preferably 20 to 30°C. If condensation step d) comprises more than one partial condensation steps, the temperature of the cooling medium TCM at the entrance of a subsequent partial condensation step is lower than the temperature of a previous partial condensation step. Most preferably, the temperature TCM is essentially the same for all partial condensation steps. This has the advantage that cooling medium from the same source can be used in each partial condensation step by splitting the cooling medium streams into parallel streams and feeding each parallel stream as a cooling medium CM to a separate partial condensation step.

[0170] The pressure of the fluid stream FS2 entering the condensation step is preferably 5 bar or less, more preferably 4 bar or less, even more preferably 3 bar or less and most preferably 2 bar or less. Preferably the pressure of fluid stream FS1 is at or around atmospheric pressure. When fluid stream FS1 is a flue gas, the pressure entering the partial condensation step is preferably in the range of 0.7 to 1.5 bar, more preferably 0.8 to 1 .3 bar and more preferably 0.9 to 1 .2 bar. When fluid stream FS1 is a tail gas from a Claus Process, the pressure of the fluid stream FS2 entering the condensation step is preferably in the range of 0.7 to 5 bar, more preferably 0.8 to 3 bar and more preferably 0.9 to 1 .5 bar.

[0171] According to the invention, the pressure loss or pressure drop over the condensation step d) is 50 mbar or less. More preferably the pressure loss over the condensation step is 35 mbar or less, even more preferably 20 mbar or less and most preferably 10 mbar or less.

[0172] The pressure loss is usually determined as the pressure difference of the fluid stream FS2 between the entrance and the exit of condensation step d). If the condensation step d) comprises two or more partial condensation steps, the pressure loss or pressure drop is measured as the pressure difference of fluid stream FS2 entering the first partial condensation step and exiting the last partial condensation step.

[0173] In a preferred embodiment, condensation step d) consists of one partial condensation step. This embodiment is essentially preferred for reducing the amine loss when used in combination with classical amine emission reduction technologies, such as the water wash and / or the dry bed. Accordingly, preferred embodiments of this preferred embodiment comprise the combination of a condensation step d) with a water wash section and the combination of condensation step d) with a water wash section and a dry bed. Combining condensation step d) with these technologies usually results in a further reduction of amine emissions compared to the case, where the alternative technologies are used alone.

[0174] In a further preferred embodiment, condensation step d) comprises more than one partial condensation steps, preferably 2 to 5 partial condensation steps and more preferably 2 to 4 and most preferably 3 partial condensation steps. When the condensation step d) comprises more than one partial condensation step, it is possible to achieve low amine emissions without a water wash or an acid wash or a dry bed.

[0175] The one or more partial condensation steps are preferably carried out in one or more suitable condensers. A condenser usually comprises the steps of condensing at least a part of a gaseous feed stream and separating the condensed part of the feed stream from the uncondensed part of the feed stream. Accordingly, a condenser comprises a heat exchanger and a separator for separating the condensed part of the stream from the part of the stream remaining in the gas phase.

[0176] The types of heat exchangers or condensers that may be designed to have a pressure drop of 50 mbar or less and which are suitable for cooling a gaseous fluid stream FS2 include plate and frame heat exchangers, plate and shell heat exchangers, shell and tube heat exchangers and plate fin heat exchangers.

[0177] A plate and frame heat exchanger usually consists of a series of thin plates that are arranged in a frame. The fluid generally flows through the channels between the plates, and heat is transferred through the plates from one fluid to the other. Plate and frame heat exchangers having a pressure drop of 50 mbar or less usually comprise at least one or more of the following design principles:

[0178] 1. Plate design: The plates in a plate and frame heat exchanger are usually designed to maximize heat transfer while minimizing pressure drop. This is usually achieved by using plates with a corrugated pattern that creates turbulence in the flow, which increases heat transfer and reduces pressure drop.

[0179] 2. Plate spacing: The spacing between the plates also affects pressure drop. The spacing can be optimized to balance the need for efficient heat transfer with a low pressure drop.

[0180] 3. Flow distribution: The flow distribution in a plate and frame heat exchanger may also be designed to ensure that the fluid flows evenly over the entire surface of the plates. This helps to minimize pressure drop by reducing the risk of flow restrictions or blockages.

[0181] 4. Channel geometry: The channel geometry, including the width and depth of the flow channels, can be optimized to minimize pressure drop. The channels can be designed to provide sufficient surface area for heat transfer while maintaining a low pressure drop. 5. Material selection: The materials used in the construction of the heat exchanger can also affect pressure drop. The use of materials with high thermal conductivity and low resistance to flow can help to reduce pressure drop.

[0182] Some examples of plate frame heat exchangers having a low pressure loss include brazed plate heat exchangers, gasketed plate heat exchangers, and welded plate heat exchangers. A plate and shell heat exchanger usually consists of a shell that is filled with a set of plates. The fluid usually flows through the channels between the plates, and heat is transferred through the plates from one fluid to the other. The shell may also serve as a pressure vessel that contains the fluid and provides structural support for the plates.

[0183] Overall, similar design principles should be followed for designing plate shell heat exchangers with a pressure loss of 50 mbar or less than those described for plate and frame heat exchangers. In addition, the shell geometry, including the diameter and length of the shell, can be optimized to minimize pressure loss.

[0184] Shell and tube heat exchangers usually designate a type of heat exchanger that consists of a tube bundle surrounded by a shell. The tube bundle contains multiple tubes that allow for the transfer of heat between two fluids. One fluid usually flows through the tubes, while the other fluid flows around the outside of the tubes in the shell. The two fluids are usually separated by a metal wall that allows heat to be transferred from one fluid to the other.

[0185] Following design principles may be applied when designing a shell tube heat exchangers for cooling gases with a pressure drop of less than 50 mbar, including:

[0186] 1. T ube diameter and pitch: The tube diameter and pitch may be optimized to achieve the desired heat transfer rate while minimizing pressure drop. Larger tube diameters and wider tube pitches tend to result in lower pressure drops but may also reduce heat transfer efficiency.

[0187] 2. Shell diameter and length: The shell diameter and length may also be optimized to achieve the desired heat transfer rate. A larger shell diameter will generally result in a lower pressure drop. The length of the shell should also be designed to provide adequate residence time for the gas to achieve the desired cooling effect.

[0188] 3. Tube layout: The tube may also be designed to minimize pressure drop while maximizing heat transfer. For example, a staggered tube layout may be more effective than an inline tube layout for achieving this balance.

[0189] 4. Baffle design: Baffles are used to direct the flow of gas through the heat exchanger. The design of the baffles may be optimized to minimize pressure drop while ensuring that the gas is evenly distributed across the tubes.

[0190] 5. Fin design: Fins can be used to enhance heat transfer by increasing the surface area of the tubes. The design of the fins may be optimized to minimize pressure drop while maximizing heat transfer efficiency.

[0191] 6. Material selection: The material selection should be based on the properties of the fluids being cooled and the operating conditions of the heat exchanger.

[0192] Condensers suitable for cooling fluid stream FS2 and having a low pressure drop are readily available.

[0193] An especially preferred condenser is the K°Flex plate heat exchanger from Kelvion. The K°Flex condenser combines the advantages of both plate-type and shell-and-and tube heat exchangers in a single unit. The K°Flex heat exchanger is a modular construction based on fully welded, gas-proof plates. From one side, the fluid flows through tubes having a diameter of about 6 to 9 mm. The other fluid flows through a plate construction, which surface induces turbulences for improved heat transfer. The fluid flowing through the straight tube-like structures flows through the heat exchanger on a direct path without any barriers. This allows for high flow rates and low pressure losses. In addition, the diameter of the tube is sufficiently large to result in a low pressure drop. Also, fouling is effectively prohibited. The corrugated plates are welded to plate-pairs and joined into standardized, cuboid modules, which may be merged into plate packages. Due to the option to integrate several plates into a plate package, different flow directions, such as crossflow and counterflow are achievable. Details regarding the design of the K°Flex condenser can be found in the journal “CAV-Prozesstechnik fur die Chemieindustrie”, Edition 07 / 2017, page 16, or in the Journal “Heat Exchanger World” published online on May 23rd, 2022 on https: / / heat-exchanger-world.com / kflex-modular-heat-exchanger-from-kelvion- thermal-solutions / and on the Kelvion website https: / / www.kelvion.com / prodijcts / prodijct / kflex / . In a preferred embodiment each partial condensation step of the one or more partial condensation steps of step d) are carried out in a separate condenser, such as the condensers described above.

[0194] Preferably, each the condenser has a single thermal zone. Within the meaning of the present invention, thermal zone characterizes a part of the condenser having an inlet for a cooling medium having the temperature of the cooling medium TCM at the inlet and the temperature TCM ’ at the outlet to the thermal zone and an inlet and outlet for fluid stream FS2 and an outlet for condensate in each thermal zone.

[0195] In a preferred embodiment of the present invention, condensation step d) is preferably carried out in a single apparatus (condenser) comprising more than one thermal zones.

[0196] Such a design is for example achievable using the K° Flex condenser from Kelvion. Since the layers of the plate packs are hydraulically separated, heat exchangers comprising different thermal zones can be realized in a single apparatus. For example, fluid stream FS2 can be cooled step in more than one thermal zone wherein each thermal zone is cooled with a cooling medium whose temperature at the entrance of each thermal zone TCM is preferably lower than the temperature of the cooling medium T’CM at the exit of the preceding thermal zone. As set out above, a condensate stream is preferably removed in each thermal zone as to achieve separate thermodynamical separation stages in each zone. When using a single apparatus with more than one thermal zone, an especially high reduction of amine emission can be achieved while achieving a compact, space-saving design and a low energy demand for transporting fluid stream FS2 through the apparatus.

[0197] After condensation step d), a treated fluid stream FS2 is obtained which has a lower amine content than the fluid stream FS2 entering the condensator.

[0198] 2ndaspect- Apparatus for Producing a Deacidified Fluid Stream

[0199] In a second aspect, the invention is directed to an apparatus for deacidifying a fluid stream comprising: a) an absorber with a. an inlet for fluid stream FS1 , b. an outlet for a deacidified fluid stream FS2; c. an inlet for an absorbent stream A1 and / or an inlet for regenerated absorbent stream A3; and d. an outlet for a laden absorbent stream A2 b) a regenerator with a. an inlet for laden absorbent stream A2; b. an outlet for regenerated absorbent stream A3; c. an outlet for an acid gas stream GS; and c) one or more condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2 and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the one or more condensers and the outlet for fluid stream FS2 of the last of the one or more condensers is 50 mbar or less.

[0200] Preferred apparatuses in which the method of the invention can be performed are depicted in figures 1 to 6.

[0201] The figures each show an apparatus for deacidifying a fluid stream, comprising a) an absorber with a. an inlet for fluid stream FS1 , b. an outlet for a deacidified fluid stream FS2; c. an inlet for an absorbent stream A1 , and / or an inlet for regenerated absorbent stream A3; and d. an outlet for a laden absorbent stream A2 b) a regenerator with a. an inlet for laden absorbent stream A2; b. an outlet for regenerated absorbent stream A3; c. an outlet for an acid gas stream GS; and c) one or more condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2 and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the one or more condensers and the outlet for fluid stream FS2 of the last of the one or more condensers is 50 mbar or less.

[0202] Figure 1 shows an embodiment of an apparatus comprising an absorber and a regenerator according to the invention and one condenser with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2 and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 and the outlet for fluid stream FS2 of the condensers is 50 mbar or less. The absorber of Figure 1 additional comprises a wash section or rescrubbing zone. The rescrubbing zone preferably has random packings to intensify the contact between the fluid stream and the scrubbing liquid.

[0203] There is preferably a feed point for scrubbing agent above the rescrubbing zone. The rescrubbing zone comprises a packing height (random packings or structured packings) of preferably 1 to 6 m, more preferably 2 to 5 and most preferably 2 to 3 m. A collecting tray (not shown) may be disposed beneath the rescrubbing zone, on which scrubbing liquid can be collected and recycled. The recycling is generally affected here by means of a pump (not shown) that pumps the scrubbing liquid from the collecting tray to the feed point. In the case of recycling, the scrubbing liquid may be cooled by means of a heat exchanger. Additionally, there may be feed for fresh make-up scrubbing liquid and a draw-off for amine comprising scrubbing liquid.

[0204] Figure 2 shows a further preferred embodiment based on Figure 1 , additionally comprising a dry bed.

[0205] The dry bed usually is a section of the absorber beneath the water wash or rescrubbing zone which preferably comprises f a structured packing.

[0206] Figure 3 shows another preferred embodiment based on Figure 2 comprising a dry bed but where the wash section was removed.

[0207] Figure 4 shows an embodiment of an apparatus comprising an absorber and a regenerator according to the invention and one condenser with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2, an outlet for condensate and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 and the outlet for fluid stream FS2 of the condensers is 50 mbar or less. The embodiment shown in Figure 3 neither comprises a backwash or rescrubbing zone or a dry bed.

[0208] Figure 5 shows a preferred embodiment and variation of Figure 4 comprising two condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2, an outlet for condensate and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the first condensers and the outlet for fluid stream FS2 of the second condensers is 50 mbar or less.

[0209] Figure 6 shows a preferred embodiment and variation of Figure 4 comprising three condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2, an outlet for condensate and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the first condensers and the outlet for fluid stream FS2 of the third condensers is 50 mbar or less.

[0210] In all figures, the absorber is configured as an absorption column.

[0211] The absorption column preferably has an absorption zone. In the context of the present invention, the absorption zone is deemed to be the section of an absorption column in which the fluid stream comes into mass transfer contact with the absorbent. To improve contact and provide a large mass transfer interface, the absorption zone preferably comprises structured packings. In a column having random packing or structured packing, the absorption zone is preferably divided into two to four packing sections (here two sections) arranged one on top of another that are separated from one another by bearing and holding trays and / or a distributor tray. If the absorption zone comprises structured packings, the height of the structured packings in the absorption zone is preferably in the range from 5 to 20 m, more preferably in the range from 6 to 15 m and most preferably in the range from 8 to 14 m.

[0212] Preferably below or in the lower region of the absorption zone, there is an inlet for the fluid stream FS1 to be deacidified.

[0213] Fresh absorbent A1 can be fed in via an inlet in the upper region or above the absorption zone. The supply of fresh absorbent may also include the supply of individual constituents of the absorbent, such as make-up water.

[0214] Regenerated absorbent A3 may be fed in via the same inlet or an inlet which is likewise in the upper region or above the absorption zone.

[0215] Preferably above the absorption zone, preferably at the top of the absorption column, there is an outlet for the deacidified fluid stream FS2.

[0216] One or several demisters (not shown) is preferably mounted in the region of the draw point for the deacidified fluid stream.

[0217] There is preferably a liquid draw for the laden absorbent A2 in the lower region of the absorber. In a preferred embodiment, there is a heat exchanger HE-CF between the liquid draw for the laden absorbent in the absorber and the feed for the laden absorbent in the regenerator. The heating medium used for this heat exchanger is preferably the recycle stream of the regenerated absorbent A3 from the bottom of the regenerator to the absorber. In this preferred embodiment, the energy demand of the overall process can be reduced.

[0218] The heat exchanger HE-CF may be configured as a plate heat exchanger or shell and tube heat exchanger. The heating medium used in the heat exchanger is preferably the bottom stream from the regenerator.

[0219] In the figures, the outlet for laden absorbent A2 from the absorber is preferably connected via a heat exchanger to the regenerator via pipelines.

[0220] The regenerator in all figures preferably comprise a regeneration zone, an evaporator, a feed inlet for the laden absorbent A2, a liquid draw (outlet) in the bottom of the regenerator for at least partially regenerates absorbent A3, a rescrubbing zone (not shown) and a outlet for the drawing of acid gas stream GS in the top region of the regenerator.

[0221] In the present context, the regeneration zone is regarded as the region of the regenerator with which the laden absorbent comes into contact with the steam which is produced by the reboiler. To improve contact and provide a large mass transfer interface, the regeneration zone preferably comprises internals, preferably random packings, structured packings and / or trays.

[0222] In a column having random packing or structured packing, the regeneration zone is preferably divided into two to four packing sections arranged one on top of another that are separated from one another by bearing and holding trays and / or a distributor tray.

[0223] If the regeneration zone comprises random packings or structured packings, the height of the random packings / structured packings in the regeneration zone is preferably in the range from 5 to 15 m, more preferably in the range from 6 to 12 m and most preferably in the range from 8 to 12 m.

[0224] If the regeneration zone comprises trays, the number of trays in the regeneration zone is preferably in the range from 10 to 30, more preferably 15 to 25 and most preferably 17 to 23 trays. The feed inlet for the laden absorbent A2 is preferably above or in the upper region of the regeneration zone.

[0225] The regenerator in figures 1 and 2 additionally comprises an reboiler HE-R .

[0226] The reboiler is preferably a kettle-type reboiler, a natural circulation evaporator or a forced circulation evaporator.

[0227] The reboiler HE-R is preferably connected to a liquid draw at the bottom of the regenerator via a pipeline to introduce absorbent stream AS1 to the reboiler HE-R. The bottom generally refers to the region beneath the regeneration zone.

[0228] The absorbent stream AS2, which usually is 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 draw at the bottom but below the regeneration zone.

[0229] In a further preferred embodiment, the bottom of the regenerator is divided by a collecting tray (not shown). The absorbent collected therein is supplied to the crossflow heat exchanger HE- CF. Stream AS2 is preferably recycled to the regenerator beneath the collecting tray.

[0230] The regenerator in all figures preferably comprises a draw point for the gaseous stream GS formed in the regeneration. The draw point for the gaseous stream GS formed in the regeneration is preferably disposed in the top region of the regenerator. There is preferably a demister (not shown) in the region of the draw point.

[0231] The regenerator in the figures preferably comprises a rescrubbing zone (not show) having internals. The internals present in the rescrubbing zone are preferably structured packings or random packings, where the packing height (random packings / structured packings) is preferably in the range from 1 to 10 m, more preferably 2 to 8 and most preferably in the range from 3 to 6 m. Alternatively, the internals present in the rescrubbing zone are trays. More particularly, the number of trays is preferably in the range of 3 to 20, more preferably 4 to 16 and is preferably 6 to 12. The trays in the scrubbing section may for example be valve trays, bubble-cap trays, Thor- mann trays or sieve trays.

[0232] In the figures, there may be a separate feed for scrubbing liquid above or in the upper region of the rescrubbing zone (not shown). If scrubbing liquid, such as freshwater, is additionally supplied, it is preferable to guide this scrubbing liquid into the regenerator together with the condensate from an additional condensation step at the top of the regenerator. Preferably, the draw point for the gaseous stream GS formed in the regenerator is connected to a top condenser (not shown). The top condenser preferably comprises a heat exchanger, a vessel for phase separation (phase separation vessel), a gas draw and a condensate outlet. Condensers used may, for example, be condensers having cooling coils or helical tubes, jacketed tube condensers and shell and tube heat exchangers.

[0233] The apparatuses described above may be used in a process according to the present invention.

[0234] 3rdaspect- Use of a Condenser with a pressure loss of 50 mbar

[0235] In a third aspect, the invention is directed to the use of a condenser having a low pressure drop for gas treating. In a preferred embodiment, one or more condensers in series, where the one or more condensers in series are designed in such a manner that the pressure-drop between the entrance of the first condenser of the one or more condensers in series and the exit of the last of the one or more condensers in series is 50 mbar or less, are used to reduce losses of the absorbent used in the absorber of an acid gas removal unit.

[0236] In a further preferred embodiment, a condenser, which is designed in such a manner that the pressure-drop between the entrance of the condenser and the exit of condensers is 50 mbar or less, and which comprises three or more thermal zones and which comprises a condensate outlet after each thermal zone, is used for the reduction of absorbent losses in an absorber.

[0237] In still a further preferred embodiment, a condenser, which is designed in such a manner that the pressure-drop between the entrance of the condenser and the exit of condensers is 50 mbar or less, and which comprises three or more thermal zones and which comprises a condensate outlet after each thermal zone, is used for the reduction of absorbent losses in an absorber of an acid gas removal unit.

[0238] Using a condenser with a low pressure drop in accordance with the method of the present invention provides for a method of further reducing amine loss or amine emissions in amine gas treating or reducing investment costs associated with more elaborate equipment used in conventional technologies.

[0239] Summary:

[0240] The method of the invention allows the preparation of a deacidified fluid stream having a reduced amine content to reduce the overall amine emissions emitted to the atmosphere. Reducing the amine emissions does not only reduce unwanted emissions to the environment but also reduce the consumption of amine solvent in the gas treating unit, reducing the amount of solvent make-up required to be refilled to compensate for amine losses. This significantly reduces the operating costs of an amine gas treating unit. When using a condenser with a low pressure drop according to the invention, a further reduction of amine emissions can be achieved, especially when using such a condenser in combination with classical technologies, such as a water wash, and / or an acid wash and / or a dry bed. When the process of the present invention comprises more than one partial condensation step, e.g. by contacting each partial condensation step in a separate condenser or by performing more than one partial condensation step in a single apparatus, it is possible to achieve low amine emissions without requiring to implement one or more classical amine reduction technology, such as water wash, acid wash and / or dry bed. When implementing more than one partial condensation steps in a single apparatus, in particular the Kelvion K Flex condenser, it is possible to reduce the investment costs and the space requirement because integrating more than one partial condensation steps in a single apparatus allows for a compact design. The invention is illustrated by the following example:

[0241] The examples are based on calculations performed using a simulation model. The phase equilibria were described using a model by Clegg and Pitzer (Clegg, S.L., Pitzer, K.S.: Thermodynamics of multicomponent, miscible, ionic solutions: Generalized equations for symmetrical electrolytes. J. Phys. Chem. 96, 3513-3520 (1992) and Clegg, S.L., Pitzer, K.S., Brimblecombe, P.: Thermodynamics of multicomponent, miscible, ionic solutions.

[0242] 2. Mixtures including unsymmetrical electrolytes. J. Phys. Chem. 96, 9470-9479 (1992))). The simulation of the absorption processes is described by means of a mass transfer-based approach; details of this 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).

[0243] In the following examples, concentrations in gaseous streams, such as concentrations expressed in mol%, are given on a dry basis, i.e. , the presence of water is neglected for the purpose of determining concentrations.

[0244] Comparison Example 1 :

[0245] Comparison Example 1 is based on the process scheme depicted in Figure 7 comprising an absorber with a water wash section and a dry bed configuration. The absorber has a diameter of 9 m and with two sections of structured packings of 9 m height each.

[0246] A feed gas having a concentration of 10 mol% CO2, 12 mol% O2 and 77 mol% N2 was introduced to the bottom of the absorber at a flow rate of 606 t / h, a temperature of 50°C and a pressure of 1 .065 bar.

[0247] Lean solvent with an amine concentration of 40 wt.% was introduced to the absorber at a flow rate of 1111 t / hr.

[0248] The treated gas above the absorber sections has a concentration of 1 .1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2 and an amine concentration of 0.022 mol%, a temperature of 62°C and a pressure of 1 .025 bar.

[0249] The treated gas enters a dry bed which is configured as a structured packing of 4 m height and a water wash section configured as a structured packing of 3 m height. The feed of water to the water wash section is 8.5 t / hr.

[0250] The composition of the treated gas leaving the absorber (deacidified fluid stream FS2) is 1.1 mol% CO2, 84.7 mol% N2and 13.2 mol% O2. The amine concentration in the treated gas leaving the absorber was reduced from 0.022 mol% to 4.25*106mol%. The temperature of the treated gas leaving the absorber was 48°C and the pressure 1.015 bar.

[0251] Example 1 :

[0252] Example 1 is based on the process scheme depicted in Figure 3 comprising an absorber without a water wash section, but with a dry bed. The treated gas leaving the wash section is passed through a condenser in which a part of the treated gas is condensed and recycled to the top of the absorber above the wash section. The dimensions of the absorber, the packings and the water wash sections are the same as in Comparison Example 1 .

[0253] The feed of feed gas, the feed gas composition and the stream of lean solvent are also the same as in Comparison Example 1 .

[0254] The treated gas above the absorber sections has a concentration of 1 .1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2 and a amine concentration of 0.022 mol%, a temperature of 62°C and a pressure of 1 .025 bar.

[0255] The treated gas enters the dry bed. The feed of water to the dry bed was 9 t / hr.

[0256] The treated gas leaving the dry bed has a concentration of 1.1 mol% CO2, 84.7 mol% N2and 13.2 mol% O2, 0,00017 mol% amines, a temperature of 59°C and a pressure of 1.025 bar.

[0257] The treated gas was introduced to a condenser with a heat duty of 25 MW where it is cooled from 59 to 48°C. The condensate stream of 35.5 t / hr was recycled to the top of the absorber above the water wash. The pressure drop between the entrance and the exit of the condenser is 5 mbar.

[0258] The composition of the treated gas leaving the condenser is 1.1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2. The amine concentration in the treated gas leaving the condenser is reduced from 0.00017 mol% to 1.3*106mol%. The temperature of the treated gas leaving the absorber was 48°C and the pressure 1 .015 bar.

[0259] Example 1 shows that the combination of a dry bed with a condenser having a low pressure loss results in lower amine emission than a classical configuration of a water wash and a dry bed shown in Comparison Example 1.

[0260] Example 2:

[0261] Example 2 is based on the process scheme depicted in Figure 4 comprising an absorber without a dry bed and without a water wash section. The treated gas (deacidified fluid stream FS2) leaving the absorber is passed through a condenser in which a part of the treated gas is condensed and recycled to the top of the absorber above the absorber section.

[0262] The feed gas and the lean amine stream are the same as in the previous examples.

[0263] A make-up water stream of 8.4 t / h was fed to the top of the absorber above the absorber sections.

[0264] The treated gas leaving absorber has a concentration of 1 .1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2, 0,022 mol% amines, a temperature of 62°C and a pressure of 1.025 bar.

[0265] The treated gas was introduced to a condenser with a heat duty of 25 MW where it is cooled from 62 to 48°C. The condensate stream of 35.6 t / hr is recycled to the top of the absorber above the absorber sections. The pressure drop between the entrance and the exit of the condenser is 5 mbar.

[0266] The composition of the treated gas leaving the condenser (deacidified fluid stream FS2) is 1.1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2. The amine concentration in the treated gas leaving the condenser is reduced from 0.022 mol% to 0.00016 mol%. The temperature of the treated gas leaving the absorber was 48°C and the pressure 1 .025 bar.

[0267] Example 2 shows that a low amine loss can already be achieved by a single condenser having a low pressure without requiring conventional technologies, such as the water wash or a dry bed.

[0268] Example 3:

[0269] Example 3 is based on the process scheme depicted in Figure 5 comprising an absorber without a dry bed and without a water wash section. The treated gas leaving the absorber (deacidified fluid stream FS2) is passed through two condensers, in which in each condenser a part of the treated gas is condensed and recycled to the top of the absorber above the absorber section.

[0270] The feed gas and the lean amine stream are the same as in the previous examples.

[0271] A make-up water stream of 8.4 t / h was fed to the top of the absorber above the absorber sections.

[0272] The treated gas leaving the absorber (deacidified fluid stream FS2) has a concentration of 1 .1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2, 0,022 mol% amines, a temperature of 62°C and a pressure of 1 .025 bar.

[0273] The treated gas is introduced to a first condenser with a heat duty of 12 MW where it is cooled from 62 to 55°C. The condensate stream of 16.4 t / hr is recycled to the top of the absorber above the water wash. The pressure drop between the entrance and the exit of the condenser is 5 mbar.

[0274] The treated gas is then introduced to a second condenser with a heat duty of 14 MW where it is cooled from 55 to 48°C. The condensate stream of 19.3 t / hr is recycled to the top of the absorber above the absorber sections. The pressure drop between the entrance and the exit of the condenser is 5 mbar.

[0275] The composition of the treated gas leaving the second condenser is 1.1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2. The amine concentration in the treated gas leaving the second condenser (deacidified fluid stream FS2) is reduced from 0.022 mol% to 9.2*10-6mol%.

[0276] The temperature of the treated gas leaving the second condenser was 48°C and the pressure 1 .025 bar.

[0277] Example 3 shows that the combination of 2 condensers with a low pressure loss results in amine losses which are nearly the same as the losses achieved with the combination of a water wash and a dry bed shown in Comparison Example 1.

[0278] Example 4:

[0279] Example 4 is based on the process scheme depicted in Figure 6 comprising an absorber without a dry bed and without a water wash section. The treated gas leaving the absorber (deacidified fluid FS2) is passed through three condensers in which in each condenser a part of the treated gas is condensed and recycled to the top of the absorber above the absorber section. The treated gas leaving absorber has a concentration of 1.1 mol% CO2, 84.7 mol% N2 and 13.2 mol% O2, 0,022 mol% amines, a temperature of 62°C and a pressure of 1.025 bar.

[0280] The treated gas is introduced to a first condenser with a heat duty of 7.7 MW where it is cooled from 62 to 57°C. The condensate stream of 10.6 t / hr is recycled to the top of the absorber above the water wash. The pressure drop between the entrance and the exit of the condenser is 5 mbar. The treated gas is then introduced to a second condenser with a heat duty of 9.9 MW where it is cooled from 57 to 52°C. The condensate stream of 13.8 t / hr is recycled to the top of the absorber above the absorber sections. The pressure drop between the entrance and the exit of the condenser is 5 mbar. The treated gas in then introduced to a third condenser with a heat duty of 8.3 MW where it is cooled from 52 to 48°C. The condensate stream of 11.4 t / hr is recycled to the top of the absorber above the absorber sections. The pressure drop between the entrance and the exit of the condenser is 5 mbar.

[0281] The composition of the treated gas leaving the third condenser (deacidified fluid stream FS2) is 1.1 mol% CO2, 84.7 mol% N2and 13.2 mol% O2. The amine concentration in the treated gas leaving the third condenser was reduced from 0.022 mol% to 8.3*10-7mol% resulting in an amine loss of 0.017 kg / h. The temperature of the treated gas leaving the third condenser is 48°C and the pressure 1 .025 bar.

[0282] Example 4 shows that the combination of three condensers with a low pressure loss results in amine losses which are substantially lower than the losses achieved with the combination of a water wash and a dry bed shown in Comparison Example 1.

Claims

Claims1 . A method for manufacture of a treated fluid stream comprising: a) an absorption step in which a fluid stream FS1 is contacted with an absorbent A1 comprising one or more amines in an absorber A to obtain an absorbent A2 laden with acid gases and an at least partly deacidified fluid stream FS2; b) a regeneration step in which at least a portion of the laden absorbent A2 obtained from step b) is regenerated in a regenerator R obtain an at least partly regenerated absorbent A3 and a gaseous stream GS comprising least one acid gas; c) a recycling step in which at least a sub stream of the regenerated absorbent A3 from step c) is recycled into the absorption step a); and wherein the method comprises an additional condensation step d), in which the partially deacidified fluid stream FS2 obtained at the top of the absorber is subjected to one or more partial condensation steps in which the fluid stream FS2 is cooled in each of the one or more condensation steps with a cooling medium CM and the pressure loss over condensation step d) is 50 mbar or less.

2. A method according to claim 1 , wherein the absorber A comprises a backwash section and step d) consists of one partial condensation step.

3. A method according to claim 1 , wherein step d) comprises two or more partial condensation steps.

4. A method according to claim 3, wherein step d) comprises three or more partial condensation steps.

5. A method according to at least one of claims 1 to 4, wherein the condensation step d) is carried out in one or more condensers.

6. A method according to claim 5, wherein the condensation step d) is carried out in a single apparatus.

7. A method according to claim 6, wherein the single apparatus comprises one or more thermal zones.

8. A method according to claim 7, wherein condensate is withdrawn after each thermal zone.

9. A method according to claim 5 or 6 wherein the one or more condensers comprise embossed plates welded to plate pairs to form tube like channels on the side of fluid stream FS2 and wave like channels on the side of cooling medium CM.

10. A method according to at least one of claims 1 to 10, wherein the temperature of deacidified fluid stream FS2 entering the condensation step d) is preferably in the range of 30 to 100°C, and during the condensation step d), the fluid stream FS2 is cooled so that the temperature of fluid stream FS2 exiting the partial condensation step d) is preferably in the range of 20 to 80°C.11 . Use of one or more condensers in series, where the one or more condensers in series are designed in such a manner that the pressure-drop between the entrance of the first condenser of the one or more condensers in series and the exit of the last of the one or more condensers in series is 50 mbar or less, to condense condensates from a fluid stream exiting the absorber of an acid gas removal unit.

12. Use of one or more condensers in series, where the one or more condensers in series are designed in such a manner that the pressure-drop between the entrance of the first condenser of the one or more condensers in series and the exit of the last of the one or more condensers in series is 50 mbar or less, to reduce losses of the absorbent used in the absorber of an acid gas removal unit.

13. Use of a condenser, which is designed in such a manner that the pressure-drop between the entrance of the condenser and the exit of condensers is 50 mbar or less, and which comprises three or more thermal zones and which comprises a condensate outlet after each thermal zone, for the reduction of absorbent losses in an absorber.

14. Use of a condenser, which is designed in such a manner that the pressure-drop between the entrance of the condenser and the exit of condensers is 50 mbar or less, and which comprises three or more thermal zones and which comprises a condensate outlet after each thermal zone, for the reduction of absorbent losses in an absorber of an acid gas removal unit.

15. Apparatus for deacidifying a fluid stream comprising a) an absorber with a. an inlet for fluid stream FS1 , b. an outlet for a deacidified fluid stream FS2; c. an inlet for an absorbent stream A1 and / or an inlet for regenerated absorbent stream A3; and d. an outlet for a laden absorbent stream A2 b) a regenerator with a. an inlet for laden absorbent stream A2; b. an outlet for regenerated absorbent stream A3; c. an outlet for an acid gas stream GS; andc) one or more condensers, each with an inlet for fluid stream FS2 and an outlet for cooled fluid stream FS2 and an inlet and outlet for cooling medium CM, wherein the pressure loss from the inlet for fluid stream FS2 of the one or more condensers and the outlet for fluid stream FS2 of the last of the one or more condensers is 50 mbar or less.

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