Process for the removal of carbon dioxide from a liquid aqueous stream

Abstract

1. A method for removing carbon dioxide from a liquid aqueous stream containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, comprising: L1 Carbon dioxide loading c≦2.5 L1 (ii) providing a liquid aqueous stream exhibiting L1 is lower than the temperature T according to (ii). L1 and heating the liquid aqueous stream to a temperature T≧90° C. at a pressure p≧0.5 bar (abs) to obtain a vapor stream V comprising carbon dioxide; L2 Carbon dioxide loading c≦0.1 L2 The method includes obtaining a liquid aqueous stream L2 exhibiting the following:

Description

[Technical Field]

[0001] The present invention relates to a method for removing carbon dioxide from a liquid aqueous stream containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, preferably obtained from a fermentation process. [Background technology]

[0002] Hexamethylenediamine, hereafter referred to as HMDA, also known as 1,6-diaminohexane or 1,6-hexanediamine, is a compound frequently used as a raw material for preparing polymers. Most HMDA is used to produce nylon 66 by condensation with adipic acid. It is also used to prepare hexamethylene diisocyanate (HDI) by phosgenation, which is a monomer feedstock for preparing polyurethanes. Furthermore, HMDA functions as a crosslinker in epoxy resins, for example.

[0003] Currently, the most widely used commercial method for producing HMDA proceeds via the hydrogenation of adiponitrile in ammonia, followed by the hydrocyanation of butadiene. However, biobased routes are also known and are described, inter alia, in U.S. Patent Application Publication No. 2017 / 0369913 A1. Typically, carbon dioxide is used in such fermentation processes, particularly to adjust the pH of the medium involved. Thus, the fermentation process results in an aqueous solution containing carbon dioxide derivatives and carbon dioxide adducts of HMDA, such as carbonates and carbamates. However, in downstream applications where HMDA is used as a raw material, free HMDA is used. Therefore, there is a need to provide an advantageous method for cleaving the derivatives and adducts to obtain a solution containing HMDA in its free form. According to the present invention, such an advantageous method is provided. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent No. 2017 / 0369913 A1 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention therefore provides a method for removing carbon dioxide from a liquid aqueous stream L1 comprising at least one hexane-1,6-diamine species comprising at least one carbon dioxide derivative of hexane-1,6-diamine, the method comprising: (i) Carbon dioxide loading L1 providing a liquid aqueous stream L1 exhibiting L1 n L1 (CO2) / n L1 (HMDA), where n L1 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1, and n L1 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L1, and c L1 is greater than or equal to 0.5 and less than or equal to 2.5, and the liquid aqueous stream L1 subjected to heating according to (ii) has a temperature T lower than the temperature T according to (ii). L1 a step comprising: (ii) heating the liquid aqueous stream L1 provided according to (i) to a temperature T of at least 90°C at a pressure p of at least 0.5 bar (abs) to obtain a vapor stream V comprising carbon dioxide, with a carbon dioxide loading c L2 Obtaining a liquid aqueous stream L2 exhibiting L2 n L2 (CO2) / n L2 (HMDA), where n L2 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L2, and n L2 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L2, and c L2includes steps where is less than or equal to 0.1. [Means for solving the problem]

[0006] As used herein, the term "carbon dioxide derivatives of hexane-1,6-diamine" includes all possible carbonates and carbamates of HMDA. Preferably, the term refers to hexamethylene-1,6-carbamate (HN-(CH)-NH-COO - ), hexamethylene-1,6-dicarbamate ( - OOC-HN-(CH2)6-NH-COO - ), hexamethylene-1,6-carbamate zwitterion ( + H3N-(CH2)6-NH-COO - ), hexamethylene-1,6-carbonate ( + H3N-(CH2)6-NH3 + CO3 2- ), hexamethylene-1,6-bicarbonate (H2N-(CH2)6-NH3 + HCO3 - ), and hexamethylene-1,6-bis-bicarbonate ( + H3N-(CH2)6-NH3 + (HCO3 - ) 2). Preferably, the counterion of hexamethylene-1,6-carbamate and hexamethylene-1,6-dicarbamate is either singly or doubly protonated HMDA. Preferably, according to the present invention, 80 to 100 mol %, more preferably 90 to 100 mol %, more preferably 95 to 100 mol % of the at least one carbon dioxide derivative of hexane-1,6-diamine consists of one or more of hexamethylene-1,6-carbamate, hexamethylene-1,6-dicarbamate, hexamethylene-1,6-carbamate zwitterion, hexamethylene-1,6-carbonate, hexamethylene-1,6-bicarbonate, and hexamethylene-1,6-bis-bicarbonate.

[0007] Generally, the at least one hexane-1,6-diamine species referred to in this invention comprises at least one carbon dioxide derivative of the above-mentioned hexane-1,6-diamine. Optionally, the at least one hexane-1,6-diamine species further comprises another hexane-1,6-diamine species, preferably hexane-1,6-diamine free base. According to one embodiment of the present invention, the at least one hexane-1,6-diamine species consists of one or more of the above-mentioned carbon dioxide derivatives of hexane-1,6-diamine and hexane-1,6-diamine free base. Preferably, 90 to 100 mol %, more preferably 95 to 100 mol %, and more preferably 98 to 100 mol % of the at least one hexane-1,6-diamine species consists of at least one carbon dioxide derivative of hexane-1,6-diamine and optionally hexane-1,6-diamine free base.

[0008] The total concentration of at least one carbon dioxide derivative of hexane-1,6-diamine in the liquid aqueous stream L1 supplied according to (i) is preferably in the range of 3 to 30% by weight, more preferably in the range of 5 to 25% by weight, more preferably in the range of 7 to 15% by weight, for example 7 to 9% by weight or 9 to 11% by weight or 11 to 13% by weight or 13 to 15% by weight, based on the total weight of stream L1. The term "total concentration of at least one carbon dioxide derivative of hexane-1,6-diamine" used in this context should be understood to be calculated on a CO2-free basis, i.e. the weight of each carbon dioxide derivative of hexane-1,6-diamine is expressed as the weight of HMDA free base, and the liquid aqueous stream L1 is assumed to be free of CO2.

[0009] (i) Carbon dioxide loading by c L1 is preferably 0.6≦c L1 ≦2.0, more preferably 0.7≦c L1 ≦1.6, e.g., 0.7≦c L1 ≦1.0 or 1.0≦c L1 ≦1.3 or 1.3≦c L1 The range is ≦1.6.

[0010] Generally, the liquid aqueous stream L1 supplied according to (i) may contain, in addition to water, at least a carbon dioxide derivative of hexane-1,6-diamine, and optionally one or more further compounds of the hexane-1,6-diamine free base. 90 to 100% by weight, preferably 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight of the liquid aqueous stream L1 supplied according to (i) is preferably composed of water, at least a carbon dioxide derivative of hexane-1,6-diamine, and optionally the hexane-1,6-diamine free base.

[0011] Preferably, the liquid aqueous stream L1 supplied according to (i) has a pH of at least 6. In particular, when the liquid aqueous stream L1 is obtained from a fermentation process, it preferably has a pH in the range of 6 to 10, more preferably in the range of 7 to 9.5, more preferably in the range of 7.5 to 9, for example, 7.5 to 8, or 8.5 to 9, or 8 to 8.5.

[0012] (ii) According to, the liquid aqueous stream L1 supplied according to (i) is heated to a temperature T of at least 90 °C of a liquid stream at a pressure p ≥ 0.5 bar (abs), and T > T L1 is. Preferably, T L1 is at least 10 °C, more preferably at least 15 °C, more preferably at least 20 °C. The preferred range of T is, for example, 10 to 50 °C or 15 to 40 °C or 20 to 30 °C. Preferably 10 °C ≤ T L1 < T, and more preferably 15 °C ≤ T L1 < T, and more preferably 20 °C ≤ T L1 < T.

[0013] (ii) According to, the temperature T at which the liquid stream L1 is heated in the column is preferably in the range of 90 to 190 °C, more preferably in the range of 100 to 180 °C, more preferably in the range of 110 to 170 °C. Thus, the preferred range can be 110 to 120 °C, or 120 to 130 °C, or 130 to 140 °C, or 140 to 150 °C, or 150 to 160 °C, 160 to 170 °C.

[0014] From step (ii) of the present invention, a liquid aqueous strip L2 is obtained which contains a significantly reduced carbon dioxide loading, since during (ii) at least one carbon dioxide derivative of HMDA is cleaved, liberating CO2, which is removed via vapor stream V, while an aqueous solution containing HMDA free base is obtained as stream L2. Preferably, the carbon dioxide loading c of stream L2 is L2 is at most 0.08, more preferably at most 0.06, more preferably at most 0.04, more preferably at most 0.03, more preferably at most 0.02. Therefore, preferably 0≦c L2 ≦0.08, more preferably 0≦c L2 ≦0.06, more preferably 0≦c L2 ≦0.04, more preferably 0≦c L2 ≦0.03, more preferably 0≦c L2 ≦0.02.

[0015] According to a first embodiment of the present invention, the heating according to (ii) is carried out in a stripping column and a stripping medium is used, and the supplying of the liquid aqueous stream L1 according to (i) comprises supplying the liquid aqueous stream L1 to the stripping column, and (ii) comprises: (ii.1) heating the liquid aqueous stream L1 provided according to (i) in a stripping column to a temperature T of at least 90°C at a pressure p of at least 0.5 bar (abs), (ii.2) At the top of the stripping column, the temperature T V obtaining a vapor stream V comprising carbon dioxide, and withdrawing said vapor stream V from the top of the stripping column; (ii.3) Temperature T L2 obtaining a liquid aqueous stream L2 comprising hexane-1,6-diamine free base at the bottom of the stripping column, said liquid aqueous stream L2 being withdrawn from the bottom of the stripping column, The method further comprises: (iii.1) The liquid aqueous stream L2 obtained according to (ii.3) is evaporated in an evaporator E1 to a temperature T VL2Water vapor flow V with L2 and temperature T L3 The aqueous liquid stream L3 having VL2 =T L3 Steps to get (iii.2) The water vapor flow V obtained according to (iii.1) L2 to the bottom section of the stripping column.

[0016] As far as the stripping medium is concerned, there are no particular limitations. Preferably, the stripping medium comprises steam, and more preferably, 90 to 100 wt. %, more preferably 95 to 100 wt. %, more preferably 99 to 100 wt. % of the stripping medium consists of steam. Thus, preferably, 0 to 10 wt. %, more preferably 0 to 5 wt. %, more preferably 0 to 1 wt. % of the stripping medium consists of one or more stripping media other than steam, preferably one or more of nitrogen, air, and lean air. Thus, although other stripping media other than steam are contemplated, it is preferred that 100 wt. % of the stripping medium consists of steam. While this steam can be introduced into the stripping column from one or more suitable external sources, it is preferred that the steam is at least partially, preferably completely, obtained in situ within the stripping column by heating the liquid aqueous stream L2 within the stripping column to a temperature T.

[0017] According to a preferred embodiment of the invention, the liquid stream L3 obtained from the evaporator E1 in (iii.1) as described above passes through a heat exchanger H1, in which part of the heat contained in L3 is transferred to another stream, preferably stream L1, which is therefore suitably preheated in H1 before entering the stripping column. The process of the invention therefore preferably comprises: (iii.3) The aqueous liquid stream L3 obtained according to (iii.1) is passed through a heat exchanger H1, and T L4 <T L3 Temperature T L4 obtaining a flow L4 having (iii.4) Temperature T L10The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 The method further comprises obtaining a liquid aqueous stream L1 having:

[0018] Preferably, the temperature difference ΔT H1 =T L10 -T L4 , i.e. the temperature difference between the temperature of L1 after passing through H1 and the temperature of stream L4, i.e. the temperature of stream L3 after transferring part of the heat contained therein to L1 in H1, is at most 20 K, more preferably at most 15 K, more preferably at most 10 K, more preferably at most 5 K.

[0019] With regard to the vapour stream V obtained at the top of the stripping column according to (ii.2), it preferably comprises water in addition to carbon dioxide. In order to separate the water from the carbon dioxide, stream V is preferably subjected to a suitable separation step, preferably a condensation step, from which a carbon dioxide-depleted water stream and a water-depleted carbon dioxide stream are obtained. Thus, the process preferably comprises, in the preferred case where the vapour stream V comprises water in addition to carbon dioxide, (iv.1) The vapor stream V obtained according to (ii.2) is subjected to condensation in a condenser C1, containing water and depleted in carbon dioxide, and having a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V The method further includes the step of obtaining:

[0020] In general, it may be advantageous to operate the stripping column with internal reflux. According to this embodiment, the stream L obtained according to (iv.1) above is V is appropriately split and the resulting stream is returned to the stripping column, preferably to the top section of the stripping column. In this case, the process of the invention preferably comprises (iv.2) The liquid stream L obtained according to (iv.1) V Two flowsV1 and L V2 Divide into L V1 to the top section of the stripping column.

[0021] As far as the respective reflux ratios are concerned, there are no particular limitations. Preferably, the reflux ratios are in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0022] According to a further embodiment of the invention, the vapour stream V obtained at the top of the stripping column is used to transfer part of its heat in a heat exchanger H2 to another stream, preferably an aqueous liquid stream L1 before entering the stripping column. As far as this embodiment is concerned, this heat exchanger H2 is preferably arranged upstream of the heat exchanger H1 according to (iii.4) above, i.e. stream L1 is preheated to a first elevated temperature before entering the stripping column, and the preheated stream obtained is then further preheated to a second elevated temperature higher than the first elevated temperature. Furthermore, according to this embodiment, the stream obtained from H2, which has transferred part of its heat to L1, preferably enters a condenser from which a carbon dioxide-depleted water stream and a water-depleted carbon dioxide stream are obtained. Thus, the process of the invention, in which the vapour stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, preferably further comprises: (iv.0) The vapor stream V obtained according to (ii.2) is passed through a heat exchanger H2 to a temperature T HVL <T V obtaining a partially condensed stream VL having (iv.1) The stream VL obtained according to (iv.0) is subjected to condensation in a condenser C1, containing water and depleted in carbon dioxide, and having a temperature T LV A liquid flow L having V and a vapor stream V containing carbon dioxide and depleted in water is obtained. V and further obtaining More preferably, the method comprises heating at a temperature T L100The liquid aqueous stream L1 having L10 >T L100 Temperature T L10 The method further comprises obtaining a liquid aqueous stream L1 having:

[0023] Preferably, the temperature difference ΔT H2 =T L100 -T HVL , i.e. the temperature difference between the temperature of L1 after passing H2 and the temperature of stream VL, i.e. the temperature of stream V after transferring part of the heat contained therein to L1 in H2, is at most 20 K, more preferably at most 15 K, more preferably at most 10 K, more preferably at most 5 K.

[0024] According to the invention, the latter embodiment may further exhibit an appropriate internal reflux to the top of the stripping column. In this regard, the process may further comprise the steps of: after (iv.0) and before (iv.1): (iv.2) The method further comprises the step of splitting the stream VL obtained according to (iv.0) into two streams VL1 and VL2, returning stream VL1 to the top section of the stripping column and subjecting stream VL2 as stream VL according to (iv.1) to condensation in condenser C1 according to (iv.2).

[0025] As far as the respective reflux ratios are concerned, there are no particular limitations. Preferably, the reflux ratios are in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0026] According to a further embodiment of the invention, the vapor stream obtained at the top of the stripping column is subjected to compression, and the respectively obtained compressed stream is used as a heat medium in the evaporator of the stripping column. The cooled compressed stream thus obtained, or a part thereof, leaving the evaporator is then preferably returned to the top of the stripping column. In this case, the process of the invention comprises: (v.1) Temperature T VKand a vapor stream V containing carbon dioxide and preferably water, preferably having the same chemical composition as the vapor stream V. K from the top of the stripping column; (v.2) The stream V withdrawn from the top of the stripping column according to (v.1) K The compressor K1 is passed through T CVK >T VK Temperature T CVK Compressible flow V with K obtaining a step of (v.3) Compressible flow V K is used as a heat medium and passed through the evaporator E1 according to (iii.1), and the liquid phase V K (l) and optionally gas phase V K (g) containing cooled compressed flow V K obtaining a step of (v.4) Preferably, the liquid phase V obtained according to (v.3) K further comprising feeding (l) or a portion thereof to the top section of a stripping column.

[0027] As shown in (v.3), the cooled compressed stream VK may contain a gas phase in addition to the liquid phase which may be returned to the top of the column. In this case, it may be preferable to subject the stream VK to an appropriate gas-liquid separation stage. As far as the respective obtained gas phase is concerned, it may be preferable to combine it with another stream obtained in the process, preferably a vapor stream obtained from a compressor arranged downstream of the heat exchanger H2 as described above. The process therefore preferably comprises: (v.5) Gas phase V obtained according to (v.3) K (g) is the vapor flow V obtained according to (iv.1). V The method may further include combining the

[0028] According to a further embodiment, the method is designed to suitably combine a stripping column with the concentration of the carbon dioxide-depleted aqueous solution, the concentration being carried out by evaporation. According to this embodiment, the stripping column is used to essentially extract the carbon dioxide contained in the liquid stream L1, and the resulting carbon dioxide-depleted aqueous stream is then subjected to a downstream evaporation stage operating at a lower pressure than the stripping column. Advantageously, for this evaporation task, the vapor stream obtained from the top of the stripping column, or a portion thereof, is used. Even more preferably, the vapor obtained from said evaporation is used to preheat the liquid stream L1 before it is sent into the stripping column. This process configuration provides a highly efficient heat-integrated process resulting in a concentrated aqueous solution containing HMDA free base.

[0029] According to this embodiment of combined stripping and concentration, the method preferably comprises: (iii.3) The vapor stream V obtained according to (ii.2) is passed through an evaporator E2 to a temperature T EV <T V obtaining a flow V having (iii.4) The aqueous liquid stream L3 obtained according to (iii.1) is evaporated in an evaporator E2 according to (iii.3), preferably T VL3 =T LL3 At temperature T VL3 Water vapor flow V with L3 and temperature T LL3 an aqueous liquid stream L having L3 The method further includes the step of obtaining:

[0030] More preferably, the method comprises: (iii.5) The water vapor flow V obtained according to (iii.4) L3 is passed through the heat exchanger H1, and T VL3H <T VL3 Temperature T VL3H Water vapor flow V with L3H obtaining a step of (iii.4) Temperature T L10The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 obtaining a liquid aqueous stream L1 having

[0031] More preferably, the method comprises the step of: L3H in a condenser C2 to obtain a liquid aqueous stream.

[0032] As mentioned above with respect to the previous embodiment, the process setup combining stripping and concentration may also exhibit, as additional features, the condensation of the vapor stream obtained from the stripping column and, more preferably, an internal reflux using at least a part of the liquid stream obtained respectively. According to this embodiment, in which the vapor stream V obtained according to (iii.3) further comprises water in addition to carbon dioxide, the method preferably comprises: (iv.1) The vapor stream V obtained according to (iii.3) is condensed in a condenser C1 to a vapor stream containing water and depleted in carbon dioxide, at a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V The method further includes the step of obtaining:

[0033] More preferably, the method comprises: (iv.2) The liquid stream L obtained according to (iv.1) V Two flows V1 and L V2 Divide into L V1 to the top section of the stripping column.

[0034] As far as the respective reflux ratios are concerned, there are no particular limitations. Preferably, the reflux ratios are in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0035] According to another preferred embodiment of the present invention, the aqueous solution depleted in carbon dioxide and containing HMDA free base for further downstream use is prepared using a multi-stage evaporation setup. According to this embodiment, step (ii) comprises the steps of: j , j=1...n, and the evaporator E j is the heating means E Hj Evaporator E j+1 is the evaporator E j and wherein providing the liquid aqueous stream L1 in accordance with (i) comprises providing the liquid aqueous stream L1 to an evaporator E1 for evaporation; For j = 1...n, (ii) is Evaporator E j The liquid aqueous stream being supplied to the evaporator E j At pressure p j At temperature T j Heat to temperature T Vj and a vapor stream V containing carbon dioxide. j and the vapor flow V j Evaporator E j Remove from the liquid aqueous stream L 1j and at temperature T L1j and c L1j n L1j (CO2) / n L1j (HMDA), where n L1j (CO2) is L 1j is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1j (HMDA) is L 1j carbon dioxide loading c, which is the molar amount of at least one hexane-1,6-diamine species in L1j Liquid aqueous flow L 1j obtain the liquid aqueous stream L 1j Evaporator E j and E j The liquid aqueous stream L extracted from 1j Evaporator E j+1 for evaporation, and a steam flow V LjEvaporator E j+1 Heating method E Hj+1 Pass through, flow W Lj+1 Heating means E Hj+1 and removing the When j=n, (ii) becomes Evaporator E n The liquid aqueous stream being supplied to the evaporator E n At pressure p n At temperature T n The steam flow V is heated to a temperature T V and a vapor stream V containing carbon dioxide. n = V, and the vapor flow V is evaporated into an evaporator E n The liquid aqueous stream L2 is taken out from the L2 and carbon dioxide loading c L2 Liquid aqueous flow L 1n =L2, and the liquid aqueous stream L2 is evaporated by an evaporator E n and removing the One parameter pair (T j ;p j ) is the parameter pair (T; p) defined in claim 1 with T≧90° C. and pressure p≧0.5 bar (abs).

[0036] According to a preferred embodiment of the multi-stage evaporation design, the parameter pair (T1; p1) realized in the first evaporator E1 is the parameter pair (T; p) defined herein above, with a temperature T≧90°C and a pressure p≧0.5 bar (abs). Preferably, the temperature T is in the range of 90-190°C, more preferably in the range of 110-190°C, more preferably in the range of 130-190°C, for example in the range of 130-150°C or 150-170°C, 170-190°C.

[0037] The number of evaporation stages n is preferably n=7, more preferably n=6, more preferably n=5, more preferably n=4, more preferably n=3 or n=2.

[0038] Preferably, each given evaporator operates at a pressure lower than the pressure of the previous evaporator, i.e., p for j=1...n-1. j+1 <p j and T j+1 <T j It is preferable that:

[0039] Furthermore, it is preferred that a given evaporator be operated so that the temperature difference between the temperature of the vapor phase resulting from said evaporator and the temperature of the liquid stream resulting from each subsequent evaporator is within a specific range. Specifically, ΔT for j=1...n-1 Ej+1 =T Vj -T L1j+1 is preferably in the range of 5 to 10K.

[0040] In particular, when n=2, -T1 is in the range of 90 to 190°C, preferably in the range of 110 to 190°C, and more preferably in the range of 130 to 190°C; -T2 is preferably in the range of 45 to 170°C, more preferably in the range of 60 to 170°C, and even more preferably in the range of 90 to 170°C.

[0041] In particular, when n=3, -T1 is in the range of 90 to 190°C, preferably in the range of 110 to 190°C, and more preferably in the range of 130 to 190°C; -T2 is in the range of 50 to 160°C, preferably in the range of 70 to 160°C, and more preferably in the range of 90 to 160°C. -T3 is preferably in the range of 35 to 140°C, more preferably in the range of 50 to 140°C, and even more preferably in the range of 70 to 140°C.

[0042] According to this multi-stage evaporation design, the carbon dioxide loading of the liquid stream obtained from a given evaporator is lower than the carbon dioxide loading of the liquid stream obtained from the previous evaporator, so that the liquid stream having the lowest carbon dioxide loading is obtained from the last evaporator, i.e., c for j=1...n-1. L1j+1 <cL1j is.

[0043] Preferably, in the case where the vapour stream V obtained from the last evaporator further comprises water in addition to carbon dioxide, the method comprises condensing the vapour stream V in a condenser C1, which comprises water and is depleted in carbon dioxide, at a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V The method further includes the step of obtaining:

[0044] Regarding the specific embodiment described above in the context of the stripping column design, the multi-evaporation design also makes it possible to provide heat integration including preheating of the stream L1 fed to the first evaporator. According to this configuration, the method preferably comprises passing the vapor stream V obtained according to (ii.2) through a heat exchanger H1 to heat it to a temperature T VL <T V and obtaining a optionally partially condensed stream VL having a temperature T L10 A liquid aqueous stream L1 having a temperature of 1000° C. is passed through a heat exchanger H1, and T L1 >T L10 Temperature T L1 The method further comprises obtaining a liquid aqueous stream L1 having:

[0045] Preferably, the temperature difference ΔT H1 =T L10 -T VL is at most 20 K, more preferably at most 10 K, more preferably at most 5 K.

[0046] As far as the first evaporator E1 is concerned, the heat medium used for evaporation purposes is supplied from an external source. In particular, the method uses a gas having a temperature T S11 Flow S with 11 The heating means E of the evaporator E1 H1 and flow S 12 Heating means E H1 Preferably, the temperature is ΔT E1 =T S12 -T L11is in the range of 5 to 10 K. More preferably, the flow S 11 is the vapor flow, and the flow S 12 is the steam condensate.

[0047] Generally, according to the present invention, the feed stream liquid aqueous stream L1 can be obtained from any suitable source. According to a preferred embodiment, the stream L1 comprising at least one hexane-1,6-diamine species, which in turn comprises at least one carbon dioxide derivative of hexane-1,6-diamine, can be obtained or is obtained by a fermentation process. Therefore, the present invention further relates to the above-mentioned method, wherein providing a liquid aqueous stream L1 according to (i) comprises preparing the stream L1 in a fermentation process.

[0048] In this fermentation process, the genetically engineered microorganism is preferably cultured or grown in a suitable culture or fermentation medium containing a nitrogen source and a carbon source in a suitable reaction vessel. During the fermentation of the genetically engineered microorganism to produce HMDA, carbon dioxide is used to adjust and control the pH of the medium. Carbon dioxide can be produced metabolically by the microorganism or artificially. Alternatively, it can be added from a suitable external source. Preferably, the growth conditions of the microorganism and the carbon dioxide concentration are controlled so that the pH is maintained at a desired value over a specific period of time during fermentation. Typically, during the fermentation process, the pH increases from a value in the range of about 6.5 to about 7.5, for example, due to the formation of a buffer by HMDA and carbon dioxide, up to a pH of about 8.5. Once the fermentation is complete, i.e., once at least one hexane-1,6-diamine species has been formed, the cells can be removed, for example, by separating the crude aqueous solution from undesired by-products contained in the retentate by suitable filtration. The aqueous fermentation solution obtained by such suitable filtration is referred to herein as the liquid aqueous stream L1.

[0049] Preferably, according to the invention, the final obtained stream L2, or stream L3, stream L4 or stream L L3The downstream stream described above as (which is now depleted of CO2 and contains free HMDA) is preferably subjected to a suitable work-up, more preferably to a suitable separation step in which free HMDA is separated from the stream. Preferably, the separation step comprises an extraction step in which the stream is contacted with a suitable organic extraction solvent. More preferably, the separation step further comprises a distillation step downstream of the extraction step in which the organic effluent obtained from the extraction is suitably distilled to separate HMDA from the extraction solvent. It may be preferable to recycle the extraction solvent thus separated back to the extraction step.

[0050] Thus, according to the invention, the stream L2 or a downstream stream obtained therefrom is extracted, and the downstream stream obtained from the stream L2 is the stream L3 defined above, the stream L4 defined above or the stream L5 defined above. L3 is.

[0051] The HMDA thus separated may be used as is or may be subjected to further purification, for example, in a further downstream distillation step.The HMDA obtained may then be used as a starting material for preparing polyamides such as nylon, polyureas, isocyanates such as hexamethylene diisocyanate, polyurethanes, and one or more copolymers thereof, as well as for (semi-quantitative) detection reactions of specific sugars, such as disaccharides such as lactose, maltose, cellobiose, lactulose, or maltulose.

[0052] The present invention is further described by the following set of embodiments, as well as combinations of embodiments resulting from the indicated dependencies and backward references. In particular, in each instance where a range of embodiments is mentioned, for example, in the context of a term, such as "the method of any one of embodiments 1 to 4," it is noted that all embodiments within this range are expressly disclosed to those skilled in the art, that is, the wording of this term should be understood by those skilled in the art as being synonymous with "the method of any one of embodiments 1, 2, 3, and 4." Furthermore, it is expressly noted that the following set of embodiments represents a properly structured part of the general description directed to preferred aspects of the present invention, and therefore properly supports, but does not express, the scope of the claims of the present invention.

[0053] 1. A method for removing carbon dioxide from a liquid aqueous stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, comprising: (i) Carbon dioxide loading L1 providing a liquid aqueous stream L1 exhibiting L1 n L1 (CO2) / n L1 (HMDA), where n L1 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1, and n L1 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L1, and c L1 is greater than or equal to 0.5 and less than or equal to 2.5, and the liquid aqueous stream L1 subjected to heating according to (ii) has a temperature T lower than the temperature T according to (ii). L1 a step comprising: (ii) heating the liquid aqueous stream L1 provided according to (i) to a temperature T of at least 90°C at a pressure p of at least 0.5 bar (abs) to obtain a vapor stream V comprising carbon dioxide, with a carbon dioxide loading c L2 Obtaining a liquid aqueous stream L2 exhibiting L2 n L2 (CO2) / n L2(HMDA), where n L2 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L2, and n L2 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L2, and c L2 is less than or equal to 0.1.

[0054] 2. The method of embodiment 1, wherein 80 to 100 mol %, preferably 90 to 100 mol %, more preferably 95 to 100 mol % of the at least one carbon dioxide derivative of hexane-1,6-diamine consists of one or more of hexamethylene-1,6-carbamate, hexamethylene-1,6-dicarbamate, hexamethylene-1,6-carbamate zwitterion, hexamethylene-1,6-carbonate, hexamethylene-1,6-bicarbonate, and hexamethylene-1,6-bis-bicarbonate.

[0055] 3. The method of embodiment 1 or 2, wherein preferably 90 to 100 mol %, preferably 95 to 100 mol %, more preferably 98 to 100 mol % of the at least one hexane-1,6-diamine species consists of at least one carbon dioxide derivative of hexane-1,6-diamine and optionally hexane-1,6-diamine free base.

[0056] 4. The method according to any one of embodiments 1 to 3, wherein the total concentration of at least one carbon dioxide derivative of hexane-1,6-diamine in the liquid aqueous stream L1 provided according to (i) is in the range of 3 to 30% by weight, preferably in the range of 5 to 25% by weight, more preferably in the range of 7 to 15% by weight, based on the total weight of stream L1.

[0057] 5.0.6≦c L1 ≦2.0, preferably 0.7≦c L1 5. The method of any one of embodiments 1 to 4, wherein the β-amino acid residue is ≦1.6.

[0058] 90 to 100% by weight, preferably 95 to 100% by weight, more preferably 99 to 100% by weight of the liquid aqueous stream L1 supplied according to 6.(i) consists of water, at least a carbon dioxide derivative of hexane-1,6-diamine, and optionally the free base of hexane-1,6-diamine, the method according to any one of Embodiments 1 to 5.

[0059] The liquid aqueous stream L1 supplied according to 7.(i) has a pH in the range of 6 to 10, preferably in the range of 7 to 9.5, more preferably in the range of 7.5 to 9 at the temperature of L1 at 25 °C, the method according to any one of Embodiments 1 to 6.

[0060] 8. 10 °C ≤ T L1 < T, preferably 15 °C ≤ T L1 < T, more preferably 20 °C ≤ T L1 < T, the method according to any one of Embodiments 1 to 7.

[0061] 9. The temperature T according to 9.(ii) is in the range of 90 to 190 °C, preferably in the range of 100 to 180 °C, more preferably in the range of 110 to 170 °C, the method according to any one of Embodiments 1 to 8.

[0062] 10. c L2 ≤ 0.08, preferably c L2 ≤ 0.06, more preferably c L2 ≤ 0.04, more preferably c L2 ≤ 0.02, the method according to any one of Embodiments 1 to 9.

[0063] 11. Step (ii) is carried out in a stripping column using a stripping medium, and supplying the liquid aqueous stream L1 according to (i) includes supplying the liquid aqueous stream L1 to the stripping column, and (ii) is (ii.1) heating the liquid aqueous stream L1 supplied according to (i) in the stripping column to a temperature T of at least 90 °C at a pressure p of at least 0.5 bar (abs), (ii.2) at the top of the stripping column, the temperature TV obtaining a vapor stream V comprising carbon dioxide, and withdrawing said vapor stream V from the top of the stripping column; (ii.3) Temperature T L2 obtaining a liquid aqueous stream L2 comprising hexane-1,6-diamine free base at the bottom of the stripping column, said liquid aqueous stream L2 being withdrawn from the bottom of the stripping column, The method further (iii.1) The liquid aqueous stream L2 obtained according to (ii.3) is evaporated in an evaporator E1 to a temperature T VL2 Water vapor flow V with L2 and temperature T L3 The aqueous liquid stream L3 having VL2 =T L3 Steps to get (iii.2) The water vapor flow V obtained according to (iii.1) L2 11. The method of any one of embodiments 1 to 10, comprising returning the olefin to the bottom section of the stripping column.

[0064] 12. The method of embodiment 11, wherein the stripping medium comprises steam, and preferably 90 to 100 wt. %, more preferably 95 to 100 wt. %, more preferably 99 to 100 wt. % of the stripping medium consists of steam.

[0065] 13. The method according to embodiment 12, wherein the vapor is obtained at least partly, preferably completely, in situ in the stripping column by heating the liquid aqueous stream L1 in the stripping column to a temperature T.

[0066] 14. The method of any one of embodiments 11 to 13, wherein 0 to 10 wt. %, preferably 0 to 5 wt. %, more preferably 0 to 1 wt. % of the stripping medium consists of one or more of nitrogen, air, and lean air.

[0067] 15. (iii.3) The aqueous liquid stream L3 obtained according to (iii.1) is passed through a heat exchanger H1 to obtain T L4 <T L3Temperature T L4 obtaining a flow L4 having (iii.4) Temperature T L10 The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 Further comprising obtaining a liquid aqueous stream L1 having The method according to any one of embodiments 11 to 14.

[0068] According to 16.(iii.4), ΔT H1 =T L10 -T L4 and ΔT H1 ≦20 K, preferably ΔT H1 ≦10 K, more preferably ΔT H1 16. The method of embodiment 15, wherein the temperature is ≦5 K.

[0069] 17. The vapor stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, and the method further comprises: (iv.1) The vapor stream V obtained according to (ii.2) is condensed in a condenser C1 to a vapor stream containing water and depleted in carbon dioxide, at a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V 17. The method of any one of embodiments 11 to 16, comprising obtaining:

[0070] 18. (iv.2) The liquid flow L obtained according to (iv.1) V Two flows V1 and L V2 Divide into L V1 to the top section of the stripping column, 18. The method of embodiment 17.

[0071] 19. The method of embodiment 18, wherein the reflux ratio is in the range of 0.01:1 to 1:1, preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0072] 20. The vapor stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, and the process comprises: (iv.0) The vapor stream V obtained according to (ii.2) is passed through a heat exchanger H2 to a temperature T HVL <T V obtaining a partially condensed stream VL having (iv.1) The stream VL obtained according to (iv.0) is condensed in a condenser C1 to a temperature T LV A liquid flow L having V and a vapor stream V containing carbon dioxide and depleted in water is obtained. V and further comprising the step of obtaining The method is temperature T L100 is passed through a heat exchanger H2 according to (iv.0) before being passed through a heat exchanger H1 according to (iii.4), L10 >T L100 Temperature T L10 17. The method according to any one of embodiments 11 to 16, further comprising obtaining a liquid aqueous stream L1 having:

[0073] 21.ΔT H2 =T L100 -T HVL and ΔT H2 ≦20 K, preferably ΔT H1 ≦10 K, more preferably ΔT H1 21. The method of embodiment 20, wherein the temperature is ≦5 K.

[0074] 22. After (iv.0) and before (iv.1), (iv.2) The method according to embodiment 20 or 21, further comprising splitting the stream VL obtained according to (iv.0) into two streams VL1 and VL2, returning stream VL1 to the top section of the stripping column and condensing stream VL2 as stream VL according to (iv.1) in a condenser C1 according to (iv.2).

[0075] 23. The method of embodiment 22, wherein the reflux ratio is in the range of 0.01:1 to 1:1, preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0076] 24.(v.1) Temperature T VK and a vapor stream V containing carbon dioxide and preferably water, preferably having the same chemical composition as the vapor stream V. K from the top of the stripping column; (v.2) The stream V withdrawn from the top of the stripping column according to (v.1) K The compressor K1 is passed through T CVK >T VK Temperature T CVK Compressible flow V with K obtaining a step of (v.3) Compressible flow V K is used as a heat medium and passed through the evaporator E1 according to (iii.1), and the liquid phase V K (l) and optionally gas phase V K (g) containing cooled compressed flow V K obtaining a step of (v.4) Preferably, the liquid phase V obtained according to (v.3) K (l), or a portion thereof, to a top section of a stripping column; The method according to any one of embodiments 11 to 23.

[0077] 25.(v.5) Gas phase V obtained according to (v.3) K (g) is the vapor flow V obtained according to (iv.1) V further comprising the step of combining with The process of embodiment 24 insofar as embodiment 24 depends on embodiment 17.

[0078] 26. (iii.3) The vapor stream V obtained according to (ii.2) is passed through an evaporator E2 to a temperature T EV <T V obtaining a flow V having (iii.4) The aqueous liquid stream L3 obtained according to (iii.1) is evaporated in an evaporator E2 according to (iii.3), preferably T VL3 =T LL3 At temperature T VL3 Water vapor flow V with L3 and temperature T LL3 an aqueous liquid stream L having L3 further comprising the step of obtaining The method according to any one of embodiments 11 to 14.

[0079] 27.(iii.5) The water vapor flow V obtained according to (iii.4) L3 is passed through the heat exchanger H1, and T VL3H <T VL3 Temperature T VL3H Water vapor flow V with L3H obtaining a step of (iii.4) Temperature T L10 The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 obtaining a liquid aqueous stream L1 having 27. The method of embodiment 26.

[0080] 28.The water vapor flow V obtained according to (iii.5) L3H in a condenser C2 to obtain a liquid aqueous stream.

[0081] 29. The vapor stream V obtained according to (iii.3) further comprises water in addition to carbon dioxide, and the method further comprises: (iv.1) The vapor stream V obtained according to (iii.3) is condensed in a condenser C1 to a vapor stream containing water and depleted in carbon dioxide, at a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V 29. The method of any one of embodiments 26 to 28, comprising obtaining:

[0082] 30. (iv.2) The liquid flow L obtained according to (iv.1) V Two flows V1 and L V2 Divide into L V1 to the top section of the stripping column, 30. The method of embodiment 29.

[0083] 31. The method of embodiment 30, wherein the reflux ratio is in the range of 0.01:1 to 1:1, preferably in the range of 0.03:1 to 0.3:1, and more preferably in the range of 0.05:1 to 0.2:1.

[0084] 32. Step (ii) is performed by using n evaporators E connected in series, where n ≥ 2. j , j=1...n, and the evaporator E j is the heating means E Hj Evaporator E j+1 is the evaporator E j and wherein providing the liquid aqueous stream L1 in accordance with (i) comprises providing the liquid aqueous stream L1 to an evaporator E1 for evaporation; For j = 1...n, (ii) is Evaporator E j The liquid aqueous stream being supplied to the evaporator E j At pressure p j At temperature T j Heat to temperature T Vj and a vapor stream V containing carbon dioxide. j and the vapor flow V j Evaporator E j Remove from the liquid aqueous stream L 1j and at temperature T L1j and c L1j n L1j (CO2) / n L1j (HMDA), where n L1j (CO2) is L 1j is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1j (HMDA) is L 1jcarbon dioxide loading c, which is the molar amount of at least one hexane-1,6-diamine species in L1j Liquid aqueous flow L 1j obtain the liquid aqueous stream L 1j Evaporator E j and E j The liquid aqueous stream L extracted from 1j Evaporator E j+1 for evaporation, and a steam flow V Lj Evaporator E j+1 Heating method E Hj+1 Pass through, flow W Lj+1 Heating means E Hj+1 and removing the When j=n, (ii) becomes Evaporator E n The liquid aqueous stream being supplied to the evaporator E n At pressure p n At temperature T n The steam flow V is heated to a temperature T V and a vapor stream V containing carbon dioxide. n = V, and the vapor flow V is evaporated into an evaporator E n The liquid aqueous stream L2 is taken out from the L2 and carbon dioxide loading c L2 Liquid aqueous flow L 1n =L2, and the liquid aqueous stream L2 is evaporated by an evaporator E n and removing the One parameter pair (T j ;p j 11. The method of any one of the preceding claims, wherein T ≥ 90°C and p ≥ 0.5 bar (abs) are the parameter pair (T; p) as defined in claim 1.

[0085] 33. The method of embodiment 32, wherein the parameter pair (T1; p1) is the parameter pair (T; p) defined in embodiment 1 with a temperature T≧90°C and a pressure p≧0.5 bar (abs).

[0086] 34. The method of embodiment 33, wherein T is in the range of 90 to 190°C, preferably in the range of 110 to 190°C, more preferably in the range of 130 to 190°C.

[0087] 35. The method according to any one of embodiments 32 to 34, wherein n=7, preferably n=6, more preferably n=5, more preferably n=4, more preferably n=3 or n=2.

[0088] 36. For j=1...n-1, p j+1 <p j and T j+1 <T j 36. The method of any one of embodiments 32 to 35, wherein

[0089] 37. For j=1...n-1, ΔT Ej+1 =T Vj -T L1j+1 37. The method of embodiment 36, wherein the temperature is in the range of 5 to 10 K.

[0090] 38. n=2, -T1 is in the range of 90 to 190°C, preferably in the range of 110 to 190°C, and more preferably in the range of 130 to 190°C, The method according to any one of embodiments 32 to 37, wherein T2 is in the range of 45 to 170°C, preferably in the range of 60 to 170°C, more preferably in the range of 90 to 170°C.

[0091] 39. n=3, -T1 is in the range of 90 to 190°C, preferably in the range of 110 to 190°C, and more preferably in the range of 130 to 190°C, -T2 is in the range of 50 to 160°C, preferably in the range of 70 to 160°C, more preferably in the range of 90 to 160°C, The method according to any one of embodiments 32 to 37, wherein T3 is in the range of 35 to 140°C, preferably in the range of 50 to 140°C, more preferably in the range of 70 to 140°C.

[0092] 40. For j=1...n-1, c L1j+1<c L1j 40. The method of any one of embodiments 32 to 39, wherein

[0093] 41. A vapor stream V further comprising water in addition to carbon dioxide, and a method comprising condensing the vapor stream V in a condenser C1 to a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V 41. The method of any one of embodiments 32 to 40, further comprising obtaining:

[0094] 42.(ii.2) The vapor stream V obtained according to (ii.2) is passed through the heat exchanger H1 and heated to a temperature T VL <T V and optionally a partially condensed stream VL, L10 A liquid aqueous stream L1 having a temperature of 1000° C. is passed through a heat exchanger H1, and T L1 >T L10 Temperature T L1 41. The method according to any one of embodiments 32 to 40, further comprising obtaining a liquid aqueous stream L1 having:

[0095] 43.ΔT H1 =T L10 -T VL and ΔT H1 ≦20 K, preferably ΔT H1 ≦10 K, more preferably ΔT H1 43. The method of embodiment 42, wherein the temperature is ≦5 K.

[0096] 44. Temperature T as a heat source S11 Flow S with 11 The heating means E of the evaporator E1 H1 and flow S 12 Heating means E H1 44. The method of any one of embodiments 32-43, further comprising removing the

[0097] 45.ΔT E1 =T S12 -T L1145. The method of embodiment 44, wherein the temperature is in the range of 5 to 10 K.

[0098] 46.Flower S 11 46. ​​The method of embodiment 44 or 45, wherein is a vapor stream.

[0099] 47. The method according to any one of embodiments 1 to 46, wherein the liquid aqueous stream L1 is obtained from a fermentation process.

[0100] 48. The method according to any one of embodiments 1 to 47, wherein stream L2 or a downstream stream obtained therefrom is subjected to extraction.

[0101] 49. The downstream flow obtained from L2 is the flow L3 defined in embodiment 11, the flow L4 defined in embodiment 8, or the flow L defined in embodiment 26. L3 49. The method of embodiment 48, wherein

[0102] 50. A method for removing carbon dioxide from a liquid aqueous stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, comprising: (i) a liquid aqueous stream L1, L1 indicates c L1 n L1 (CO2) / n L1 (HMDA), where n L1 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1, and n L1 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L1, and 0.5≦c L1 ≦2.5, and the liquid aqueous stream L1 subjected to heating according to (ii) has a temperature T lower than the temperature T according to (ii). L1 providing a liquid aqueous stream L1 having (ii) heating the liquid aqueous stream L1 provided according to (i) to a temperature T≧90° C. at a pressure p≧0.5 bar (abs) to obtain a vapor stream V comprising carbon dioxide, with a carbon dioxide loading cL2 A liquid aqueous stream L2 exhibiting c L2 n L2 (CO2) / n L2 (HMDA), where n L2 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L2, and n L2 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L2, and c L2 obtaining a liquid aqueous stream L2 having a pH of ≦0.1, Step (ii) is carried out in a stripping column using a stripping medium, and supplying a liquid aqueous stream L1 in accordance with (i) comprises supplying the liquid aqueous stream L1 to the stripping column, and (ii) (ii.1) heating the liquid aqueous stream L1 provided according to (i) in a stripping column to a temperature T of at least 90°C at a pressure p of at least 0.5 bar (abs), (ii.2) At the top of the stripping column, the temperature T V obtaining a vapor stream V comprising carbon dioxide, and withdrawing said vapor stream V from the top of the stripping column; (ii.3) Temperature T L2 obtaining a liquid aqueous stream L2 comprising hexane-1,6-diamine free base at the bottom of the stripping column, said liquid aqueous stream L2 being withdrawn from the bottom of the stripping column, The method is further (iii.1) The liquid aqueous stream L2 obtained according to (ii.3) is evaporated in an evaporator E1 to a temperature T VL2 Water vapor flow V with L2 and temperature T L3 The aqueous liquid stream L3 having VL2 =T L3 Steps to get (iii.2) The water vapor flow V obtained according to (iii.1) L2 to the bottom section of the stripping column; The stripping medium preferably contains steam, and preferably 90 to 100% by weight, more preferably 95 to 100% by weight, more preferably 99 to 100% by weight of the stripping medium is steam; A process wherein the vapor is obtained at least partly, more preferably completely, in situ in the stripping column by heating a liquid aqueous stream L1 to a temperature T in the stripping column.

[0103] 51. (iii.3) The aqueous liquid stream L3 obtained according to (iii.1) is passed through a heat exchanger H1 to obtain T L4 <T L3 Temperature T L4 obtaining a flow L4 having (iii.4) Temperature T L10 The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 obtaining a liquid aqueous stream L1 having According to (iii.4), ΔT H1 =T L10 -T L4 and preferably ΔT H1 ≦20 K, more preferably ΔT H1 ≦10 K, more preferably ΔT H1 ≦5 K, The method of embodiment 50.

[0104] 52. The vapor stream V obtained according to (ii.2) further contains water in addition to carbon dioxide, and the process (iv.1) The vapor stream V obtained according to (ii.2) is condensed in a condenser C1 to produce a vapor stream containing water and depleted in carbon dioxide at a temperature T LV A liquid flow L having V and further obtaining a carbon dioxide-containing, water-depleted vapor stream V V and further comprising the step of obtaining The method preferably comprises: (iv.2) The liquid stream L obtained according to (iv.1) V Two flows V1and L V2 Divide into L V1 to the top section of the stripping column; 52. The method of embodiment 50 or 51, wherein the reflux ratio is preferably in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, more preferably in the range of 0.05:1 to 0.2:1.

[0105] 53. The vapor stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, and the process comprises: (iv.0) The vapor stream V obtained according to (ii.2) is passed through a heat exchanger H2 to a temperature T HVL <T V obtaining a partially condensed stream VL having (iv.1) The stream VL obtained according to (iv.0) is condensed in a condenser C1 to a temperature T LV A liquid flow L having V and a vapor stream V containing carbon dioxide and depleted in water is obtained. V and further comprising the step of obtaining The method is temperature T L100 The liquid aqueous stream L1 having L10 >T L100 Temperature T L10 obtaining a liquid aqueous stream L1 having ΔT H2 =T L100 -T HVL and preferably ΔT H2 ≦20 K, more preferably ΔT H1 ≦10 K, more preferably ΔT H1 52. The method of embodiment 50 or 51, wherein the pH is ≦5 K.

[0106] 54. After (iv.0) and before (iv.1), (iv.2) further comprising the steps of splitting the stream VL obtained according to (iv.0) into two streams VL1 and VL2, returning stream VL1 to the top section of the stripping column and condensing stream VL2 as stream VL according to (iv.1) in a condenser C1 according to (iv.2), 54. The method of embodiment 53, wherein the reflux ratio is preferably in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, more preferably in the range of 0.05:1 to 0.2:1.

[0107] 55.(v.1) Temperature T VK and a vapor stream V containing carbon dioxide and preferably water, preferably having the same chemical composition as the vapor stream V. K from the top of the stripping column; (v.2) The stream V withdrawn from the top of the stripping column according to (v.1) K The compressor K1 is passed through T CVK >T VK Temperature T CVK Compressible flow V with K obtaining a step of (v.3) Compressible flow V K is used as a heat medium and passed through the evaporator E1 according to (iii.1), and the liquid phase V K (l) and optionally gas phase V K (g) containing cooled compressed flow V K obtaining a step of (v.4) Preferably, the liquid phase V obtained according to (v.3) K (l), or a portion thereof, to a top section of a stripping column; The method according to any one of embodiments 50 to 54.

[0108] 56. (iii.3) The vapor stream V obtained according to (ii.2) is passed through an evaporator E2 to a temperature T EV <T V obtaining a flow V having (iii.4) The aqueous liquid stream L3 obtained according to (iii.1) is evaporated in an evaporator E2 according to (iii.3), preferably T VL3 =T LL3 At temperature T VL3 Water vapor flow V with L3 and temperature T LL3 an aqueous liquid stream L having L3 and further comprising the step of obtaining The method preferably comprises (iii.5) The water vapor flow V obtained according to (iii.4) L3 is passed through the heat exchanger H1, and T VL3H <T VL3 Temperature T VL3H Water vapor flow V with L3H obtaining a step of (iii.4) Temperature T L10 The liquid aqueous stream L1 having L1 >T L10 Temperature T L1 obtaining a liquid aqueous stream L1 having The water vapor flow V obtained according to (iii.5) L3H is condensed, preferably in a condenser C2, to obtain a liquid aqueous stream.

[0109] 57. The vapor stream V obtained according to (iii.3) further contains water in addition to carbon dioxide, and the process (iv.1) The vapor stream V obtained according to (iii.3) is condensed in a condenser C1 to produce a vapor stream containing water and depleted in carbon dioxide at a temperature T LV A liquid flow L having V and further obtaining a carbon dioxide-containing, water-depleted vapor stream V V and further comprising the step of obtaining The method preferably comprises: (iv.2) The liquid stream L obtained according to (iv.1) V Two flows V1 and L V2 Divide into L V1 to the top section of the stripping column; 57. The process according to embodiment 56, wherein the reflux ratio is preferably in the range of from 0.01:1 to 1:1, more preferably in the range of from 0.03:1 to 0.3:1, more preferably in the range of from 0.05:1 to 0.2:1.

[0110] 58. 80 to 100 mol %, preferably 90 to 100 mol %, more preferably 95 to 100 mol % of at least one carbon dioxide derivative of hexane-1,6-diamine consists of one or more of hexamethylene-1,6-carbamate, hexamethylene-1,6-dicarbamate, hexamethylene-1,6-carbamate zwitterion, hexamethylene-1,6-carbonate, hexamethylene-1,6-bicarbonate, and hexamethylene-1,6-bis-bicarbonate; 58. The method of any one of embodiments 50 to 57, wherein preferably 90 to 100 mol %, more preferably 95 to 100 mol %, more preferably 98 to 100 mol % of the at least one hexane-1,6-diamine species consists of at least one carbon dioxide derivative of hexane-1,6-diamine, and optionally the free base of hexane-1,6-diamine.

[0111] 59.0.6≦c L1 ≦2.0, preferably 0.7≦c L1 59. The method of any one of embodiments 50 to 58, wherein the β-amino acid residue is ≦1.6.

[0112] 60. 90 to 100 wt. %, preferably 95 to 100 wt. %, more preferably 99 to 100 wt. % of the liquid aqueous stream L1 provided according to (i) consists of water, said at least carbon dioxide derivative of hexane-1,6-diamine, and optionally hexane-1,6-diamine free base; 60. The method according to any one of embodiments 50 to 59, wherein the liquid aqueous stream L1 provided according to (i) has a pH, at a temperature of L1 of 25°C, preferably in the range of 6 to 10, more preferably in the range of 7 to 9.5, more preferably in the range of 7.5 to 9.

[0113] 61.10℃≦T L1<T, preferably 15 °C ≤ T L1 <T, more preferably 20 °C ≤ T L1 <T and (ii) The temperature T according to (ii) is preferably in the range of 90 to 190 °C, more preferably in the range of 100 to 180 °C, and even more preferably in the range of 110 to 170 °C, the method according to any one of Embodiments 50 to 60.

[0114] 62.c L2 ≤ 0.08, preferably c L2 ≤ 0.06, more preferably c L2 ≤ 0.04, more preferably c L2 ≤ 0.02, the method according to any one of Embodiments 50 to 61.

[0115] 63. Can the liquid aqueous stream L1 be obtained by a fermentation process, or is obtained, and the stream L2 or a downstream stream obtained therefrom is subjected to extraction, and the downstream stream obtained from L2 is the stream L3 defined in Embodiment 50, the stream L4 defined in Embodiment 51, or the stream L defined in Embodiment 56 L3 is the method according to any one of Embodiments 50 to 62.

[0116] 64. A method for removing carbon dioxide from a liquid aqueous stream L1 containing at least one hexane-1,6-diamine species containing at least one carbon dioxide derivative of hexane-1,6-diamine, (i) The liquid aqueous stream L1 showing the carbon dioxide loading c L1 where c L1 is n L1 (CO2) / n L1 defined as (HMDA), and n L1 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1, and n L1 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L1, 0.5 ≤ c L1 ≤ 2.5, and the liquid aqueous stream L1 subjected to heating according to (ii) is T lower than the temperature T according to (ii) L1providing a liquid aqueous stream L1 having (ii) heating the liquid aqueous stream L1 provided according to (i) to a temperature T≧90° C. at a pressure p≧0.5 bar (abs) to obtain a vapor stream V comprising carbon dioxide, with a carbon dioxide loading c L2 A liquid aqueous stream L2 exhibiting c L2 n L2 (CO2) / n L2 (HMDA), where n L2 (CO2) is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L2, and n L2 (HMDA) is the molar amount of at least one hexane-1,6-diamine species in L2, and c L2 obtaining a liquid aqueous stream L2 having a liquid content of ≦0.1 Step (ii) is performed by using n series-connected evaporators E j , j=1...n, and the evaporator E j is the heating means E Hj Evaporator E j+1 is the evaporator E j and wherein providing the liquid aqueous stream L1 in accordance with (i) comprises providing the liquid aqueous stream L1 to an evaporator E1 for evaporation; For j = 1...n, (ii) is Evaporator E j The liquid aqueous stream being supplied to the evaporator E j At pressure p j At temperature T j Heat to temperature T Vj and a vapor stream V containing carbon dioxide. j and the vapor flow V j Evaporator E j Remove from the liquid aqueous stream L 1j and at temperature T L1j and c L1j n L1j (CO2) / n L1j (HMDA), where n L1j (CO2) is L 1jis the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in L1j (HMDA) is L 1j carbon dioxide loading c, which is the molar amount of at least one hexane-1,6-diamine species in L1j Liquid aqueous flow L 1j obtain the liquid aqueous stream L 1j Evaporator E j and obtaining from E j The liquid aqueous stream L extracted from 1j Evaporator E j+1 for evaporation, and a steam flow V Lj Evaporator E j+1 Heating method E Hj+1 Pass through, flow W Lj+1 Heating means E Hj+1 and removing the When j=n, (ii) becomes Evaporator E n The liquid aqueous stream being supplied to the evaporator E n At pressure p n At temperature T n The steam flow V is heated to a temperature T V and a vapor stream V containing carbon dioxide. n = V, and the vapor flow V is evaporated into an evaporator E n The liquid aqueous stream L2 is taken out from the L2 and carbon dioxide loading c L2 Liquid aqueous flow L 1n =L2, and the liquid aqueous stream L2 is evaporated by an evaporator E n and removing the One parameter pair (T j ;p j ) is the parameter pair (T; p) as defined in embodiment 1, where T≧90° C. and pressure p≧0.5 bar (abs), Preferably, n=7, more preferably n=6, more preferably n=5, more preferably n=4, more preferably n=3 or n=2.

[0117] 65. The parameter pair (T1; p1) is the parameter pair (T; p) defined in embodiment 1 at a temperature T ≥ 90 ° C and a pressure p ≥ 0.5 bar (abs); 65. The method according to embodiment 64, wherein T is preferably in the range of 90 to 190 °C, more preferably in the range of 110 to 190 °C, more preferably in the range of 130 to 190 °C.

[0118] 66. For j=1...n-1, p j+1 <p j; c L1j+1 <c L1j and T j+1 <T j and for j=1...n-1, ΔT Ej+1 =T Vj -T L1j+1 66. The method according to any one of embodiments 64 to 65, wherein the temperature is preferably in the range of 5 to 10 K.

[0119] 67. A vapor stream V further comprising water in addition to carbon dioxide, and a method comprising condensing the vapor stream V in a condenser C1 to a temperature T LV A liquid flow L having V and further obtaining a vapor stream V containing carbon dioxide and depleted in water. V 67. The method of any one of embodiments 64 to 66, further comprising obtaining:

[0120] 68.(ii.2) The vapor stream V obtained according to (ii.2) is passed through the heat exchanger H1 and heated to a temperature T VL <T V and the method further comprises obtaining a optionally partially condensed stream VL having a temperature T L10 A liquid aqueous stream L1 having a temperature of 1000° C. is passed through a heat exchanger H1, and T L1 >T L10 Temperature T L1 67. The method according to any one of embodiments 64 to 66, further comprising obtaining a liquid aqueous stream L1 having:

[0121] 80 to 100 mol%, preferably 90 to 100 mol%, more preferably 95 to 100 mol% of at least one carbon dioxide derivative of hexane-1,6-diamine consists of one or more of hexamethylene-1,6-carbamate, hexamethylene-1,6-dicarbamate, hexamethylene-1,6-carbamate zwitterion, hexamethylene-1,6-carbonate, hexamethylene-1,6-bicarbonate, and hexamethylene-1,6-bis-bicarbonate, Preferably 90 to 100 mol%, more preferably 95 to 100 mol%, even more preferably 98 to 100 mol% of at least one hexane-1,6-diamine species consists of at least one carbon dioxide derivative of hexane-1,6-diamine and optionally the free base of hexane-1,6-diamine, according to any one of embodiments 64 to 68.

[0122] 70. 0.6 ≦ c L1 ≦ 2.0, preferably 0.7 ≦ c L1 ≦ 1.6, according to any one of embodiments 64 to 69.

[0123] 90 to 100 wt%, preferably 95 to 100 wt%, more preferably 99 to 100 wt% of the liquid aqueous stream L1 supplied according to (i) consists of water, the at least one carbon dioxide derivative of hexane-1,6-diamine, and optionally the free base of hexane-1,6-diamine, The liquid aqueous stream L1 supplied according to (i) has a pH in the range of preferably 6 to 10, more preferably 7 to 9.5, even more preferably 7.5 to 9 at a temperature of 25 °C of L1, according to any one of embodiments 64 to 69.

[0124] 72. 10 °C ≦ T L1 < T, preferably 15 °C ≦ T L1 < T, more preferably 20 °C ≦ T L1 < T, and 72. The method according to any one of embodiments 64 to 71, wherein the temperature T according to (ii) is preferably in the range of 90 to 190°C, more preferably in the range of 100 to 180°C, more preferably in the range of 110 to 170°C.

[0125] 73.c L2 ≦0.08, preferably c L2 ≦0.06, more preferably c L2 ≦0.04, more preferably c L2 73. The method of any one of embodiments 64-72, wherein the β-amino acid residue is ≦0.02.

[0126] In the context of the present invention, the term "X is one or more of A, B and C," where X is a given characteristic and A, B and C each represent a specific realization of said characteristic, should be understood as disclosing that X is either A, or B, or C, or A and B, or A and C, or B and C, or A, B and C. In this regard, it should be noted that one skilled in the art can translate the above abstract terms into concrete examples, e.g., X is a temperature and A, B and C are specific temperatures such as 10°C, 20°C, and 30°C. In this regard, it is further noted that those skilled in the art can expand the above terms to less specific realizations of said feature, such as, for example, "X is one or more of A and B" disclosing that X is either A, or B, or A and B, or to more specific realizations of said feature, such as, for example, "X is one or more of A, B, C, and D" disclosing that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D. [Brief explanation of the drawings]

[0127] [Figure 1]1 shows a schematic diagram of the process according to the invention. According to FIG. 1, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and removed. At the bottom of the stripping column, a liquid aqueous stream L2 depleted in carbon dioxide is obtained and removed, and then sent to an evaporator E1, where L2 is heated to obtain a vapor stream VL2 and a liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. [Figure 2] Schematic diagram of the process according to the invention. According to FIG. 2, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and removed. At the bottom of the stripping column, a liquid aqueous stream L2 depleted in carbon dioxide is obtained and removed from the stripping column. Liquid stream L2 is split, and a portion of L2 is sent to an evaporator E1, where it is heated to obtain a vapor stream VL2 and a liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. [Figure 3]Schematic diagram of the process according to the invention, including preheating of liquid stream L1. According to FIG. 3, aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through heat exchanger H1, and the heated stream L1 is sent to the top section of a stripping column. At the top of the stripping column, vapor stream V containing carbon dioxide is obtained and removed. At the bottom of the stripping column, carbon dioxide-depleted liquid aqueous stream L2 is obtained and removed from the stripping column. Liquid stream L2 is sent to evaporator E1, where it is heated to obtain vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. Liquid stream L3 is used as a heat carrier in heat exchanger H1 to preheat liquid stream L1, resulting in cooled stream L4. [Figure 4] 4 is a schematic diagram of a process according to the present invention, including preheating of liquid stream L1 and further reflux. According to FIG. 4, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through heat exchanger H1, and the heated stream L1 is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and removed. The vapor stream V is then sent to condenser C1, from which a vapor stream VV and a liquid stream LV are obtained and removed from C1. The liquid stream LV is then split into two liquid streams LV1 and LV2, and stream LV1 is returned to the top section of the stripping column. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and removed from the stripping column. The liquid stream L2 is sent to evaporator E1, where it is heated to obtain a vapor stream VL2 and a liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. Liquid stream L3 is used as a heat medium in heat exchanger H1 to preheat liquid stream L1, resulting in the respective cooled stream L4. [Figure 5]Schematic diagram of a process according to the invention, including two-stage preheating of liquid stream L1. According to FIG. 5, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is passed through a first heat exchanger H2, and the heated stream L1 passes through a second heat exchanger H1, where it is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and withdrawn. The vapor stream V is used as a heat medium in the first heat exchanger H2 to initially preheat the liquid stream L1, resulting in a partially condensed stream VL, which is then sent to a condenser C1, from which a vapor stream VVL and a liquid stream LVL are obtained and withdrawn from C1. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and withdrawn from the stripping column. Liquid stream L2 is sent to evaporator E1, where L2 is heated to produce vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. Liquid stream L3 is used as a heat carrier in second heat exchanger H1 to preheat liquid stream L1, resulting in cooled stream L4. [Figure 6]6 is a schematic diagram of a process according to the present invention, including a two-stage preheating of the liquid stream L1 and further refluxing. According to FIG. 6, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through a first heat exchanger H2, and the heated stream L1 passes through a second heat exchanger H1, where it is sent to the top section of a stripping column. In FIG. 6, the stripping column includes an additional backwash section in the top section of the column, and the liquid stream L1 is introduced into the column between the stripping section and the backwash section. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and withdrawn. The vapor stream V is used as a heat medium in the first heat exchanger H2 to initially preheat the liquid stream L1, resulting in a partially condensed stream VL, which is then sent to a condenser C1, from which a vapor stream VVL and a liquid stream LVL are obtained and withdrawn from C1. This liquid stream L1 is then split into two streams LVL1 and LVL2, with stream LVL1 being returned to the top section of the stripping column. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and removed from the stripping column. Liquid stream L2 is sent to an evaporator E1, where it is heated to obtain vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. Liquid stream L3 is used as a heat medium in a second heat exchanger H1 to preheat liquid stream L1, thereby obtaining cooled stream L4. [Figure 7]7 shows a schematic diagram of a process according to the invention, comprising a two-stage preheating of the liquid stream L1, followed by reflux and top vapor compression. According to FIG. 7, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through a first heat exchanger H2, and the heated stream L1 passes through a second heat exchanger H1, where it is sent to the top section of a stripping column. In FIG. 6, the stripping column includes an additional backwash section in the top section of the column, and the liquid stream L1 is introduced into the column between the stripping section and the backwash section. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and removed. A portion VK is separated from the overhead vapor stream V, and the remaining stream V is used as a heat transfer medium in the first heat exchanger H2 for the initial preheating of liquid stream L1, resulting in a partially condensed stream VL, which is then sent to the condenser C1, from which a vapor stream VVL and a liquid stream LVL are obtained and removed from C1. This liquid stream L1 is then split into two streams LVL1 and LVL2, and stream LVL1 is returned to the top section of the stripping column. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and removed from the stripping column. Liquid stream L2 is sent to the evaporator E1, where it is heated to produce vapor stream VL2 and liquid stream L3. Stream VK separated from vapor stream V passes through compressor K1, resulting in a compressed stream VK, which is used as a heat transfer medium to heat stream L3 in the evaporator E1. The cooled stream VK obtained in each case is then sent to a drum, from which the liquid stream VK(l) is sent to the top section of the stripping column above the backwash section, from where the gas stream VK(g) is combined with the vapor stream VVL obtained from the condenser C1. The stream VL2 obtained from the evaporator E1 is returned to the bottom section of the stripping column for heating purposes. The liquid stream L3 is used as a heat carrier in a second heat exchanger H1 to preheat the liquid stream L1, resulting in the cooled stream L4. [Figure 8]8 is a schematic diagram of a method according to the present invention, further comprising the evaporation of stream L3. According to FIG. 8, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and withdrawn. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and withdrawn, and then sent to an evaporator E1, where L2 is heated to obtain a vapor stream VL2 and a liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. The liquid stream L3 obtained from the evaporator E1 passes through an evaporator E2, which obtains a vapor stream VL3 and a liquid stream LL3, which is depleted of carbon dioxide and enriched in hexane-1,6-diamine. The vapor stream V obtained from the top of the stripping column is used as a heat carrier for the evaporator E2. [Figure 9] 9 is a schematic diagram of a method according to the present invention, further comprising the evaporation of stream L3 and preheating of stream L1. According to FIG. 9, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through heat exchanger H1, and the heated stream L1 is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and withdrawn. At the bottom of the stripping column, a liquid aqueous stream L2 depleted in carbon dioxide is obtained and withdrawn, and then sent to evaporator E1, where L2 is heated to obtain vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. Liquid stream L3 obtained from evaporator E1 passes through evaporator E2 to obtain vapor stream VL3 and liquid stream LL3, which is depleted in carbon dioxide and enriched in hexane-1,6-diamine. The vapor stream VL3 is used as a heat carrier in the heat exchanger H1 to preheat the liquid stream L1, thereby obtaining the cooled stream VL3H. The vapor stream V obtained from the top of the stripping column is used as a heat carrier in the evaporator E2. [Figure 10] 10 is a schematic diagram of a process according to the present invention, further comprising evaporation of stream L3 and preheating of stream L1, and further comprising condensation of the vapor stream. According to FIG. 10, aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through heat exchanger H1, and the heated stream L1 is sent to the top section of a stripping column. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and removed. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and removed, and then sent to evaporator E1, where L2 is heated to obtain vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. The liquid stream L3 obtained from the evaporator E1 passes through the evaporator E2, producing a vapor stream VL3 and a liquid stream LL3, the latter depleted of carbon dioxide and enriched in hexane-1,6-diamine. The vapor stream VL3 is used as a heat transfer medium in the heat exchanger H1 to preheat the liquid stream L1, producing a cooled stream VL3H. The vapor stream V obtained from the top of the stripping column serves as a heat transfer medium in the evaporator E2. The cooled stream V from the evaporator E2 is then sent to the condenser C1, which produces a liquid stream LV and a vapor stream VV. The cooled stream VL3H from the heat exchanger H1 then passes through the condenser C2, producing a liquid aqueous stream as the condensate. [Figure 11]11 is a schematic diagram of a process according to the present invention, further comprising the evaporation of stream L3 and preheating of stream L1, and further comprising the condensation and reflux of the vapor stream. According to FIG. 11, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through heat exchanger H1, and the heated stream L1 is sent to the top section of the stripping column. In FIG. 11, the stripping column includes an additional backwash section in the top section of the column, and liquid stream L1 is introduced into the column between the stripping section and the backwash section. At the top of the stripping column, a vapor stream V containing carbon dioxide is obtained and withdrawn. At the bottom of the stripping column, a carbon dioxide-depleted liquid aqueous stream L2 is obtained and withdrawn, then sent to evaporator E1, where L2 is heated to obtain vapor stream VL2 and liquid stream L3. Stream VL2 is then returned to the bottom section of the stripping column for heating purposes. The liquid stream L3 obtained from the evaporator E1 passes through the evaporator E2, producing a vapor stream VL3 and a liquid stream LL3, the latter depleted of carbon dioxide and enriched in hexane-1,6-diamine. The vapor stream VL3 is used as a heat transfer medium in the heat exchanger H1 to preheat the liquid stream L1, producing a cooled stream VL3H. The vapor stream V obtained from the top of the stripping column serves as a heat transfer medium in the evaporator E2. The cooled stream V obtained from the evaporator E2 is then sent to the condenser C1, which produces a liquid stream LV and a vapor stream VV. The cooled stream VL3H obtained from the heat exchanger H1 then passes through the condenser C2, producing a liquid aqueous stream as the condensate. The liquid stream LV obtained from the condenser C1 is then split into two streams LV1 and LV2, with the stream LV1 being returned as reflux to the top section of the stripping column above the backwash section of the stripping column. [Figure 12]12 is a schematic diagram of a method according to the invention, comprising a two-stage evaporation of stream L1. According to FIG. 12, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is fed to a first evaporator E1 equipped with a heating means EH1. A heat carrier stream S11 heats stream L1 passing through the heating means EH1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, the latter being depleted of carbon dioxide and enriched in hexane-1,6-diamine. From the heating means EH1, a cooled stream S12 is obtained. The liquid stream L11 is then fed to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E1 provides a vapor stream V2 (V) and a liquid stream L11 (L2), the latter depleted in carbon dioxide and enriched in hexane-1,6-diamine, and the heating means EH2 provides a cooled stream WL2. [Figure 13]13 is a schematic diagram of a process according to the present invention, comprising a two-stage evaporation of stream L1 and further comprising condensation of the vapor stream obtained from the downstream evaporation stage. According to FIG. 13, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is fed to a first evaporator E1 equipped with a heating means EH1. A heat carrier stream S11 heats stream L1 passing through the heating means EH1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, the latter being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The cooled stream S12 is then obtained from the heating means EH1. The liquid stream L11 is then fed to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E1 provides a vapor stream V2 (V) and a liquid stream L12 (L2), the liquid stream L2 being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH2 provides a cooled stream WL2. The vapor stream V2 (V) obtained from the evaporator E2 is then sent to a condenser C1, from which a condensed liquid stream LV and a vapor stream VV are obtained. [Figure 14]14 is a schematic diagram of a method according to the invention, comprising a three-stage evaporation of stream L1. According to FIG. 14, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is fed to a first evaporator E1 equipped with a heating means EH1. A heat carrier stream S11 heats stream L1 passing through the heating means EH1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, the latter being depleted of carbon dioxide and enriched in hexane-1,6-diamine. From the heating means EH1, a cooled stream S12 is obtained. The liquid stream L11 is then fed to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E2 produces a vapor stream V2 and a liquid stream L12, the latter depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH2 produces a cooled stream WL2, respectively. The liquid stream L12 is then fed to a third evaporator E3 equipped with a heating means EH3. The vapor stream V2 from the second evaporator E2 passes through the heating means EH3 as a heat medium for heating the liquid stream L12. The evaporator E3 produces a vapor stream V3 (V) and a liquid stream L13 (L2), the former depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH3 produces a cooled stream WL3, respectively. [Figure 15]14 is a schematic diagram of a process according to the present invention, comprising a three-stage evaporation of stream L1 and further comprising condensation of the vapor stream obtained from the downstream evaporation stage. According to FIG. 14, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, is fed to a first evaporator E1 equipped with a heating means EH1. A heat carrier stream S11 heats stream L1 passing through the heating means EH1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, the latter being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The cooled stream S12 is then obtained from the heating means EH1. The liquid stream L11 is then fed to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E2 produces a vapor stream V2 and a liquid stream L12, the latter depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH2 produces a cooled stream WL2. The liquid stream L12 is then sent to a third evaporator E3, which is equipped with a heating means EH3. The vapor stream V2 from the second evaporator E2 passes through the heating means EH3 as a heat medium for heating the liquid stream L12. The evaporator E3 produces a vapor stream V3(V) and a liquid stream L13(L2), the former depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH3 produces a cooled stream WL3. The vapor stream V3(V) from the evaporator E3 is then sent to a condenser C1, which produces a condensed liquid stream LV and a vapor stream VV. [Figure 16]16 is a schematic diagram of a method according to the present invention, comprising a two-stage evaporation of stream L1 and further comprising preheating of stream L1. According to FIG. 16, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through a heat exchanger H1, and the heated liquid stream L1 is sent to a first evaporator E1 equipped with a heating means EH1. Through the heating means EH1, a heat carrier stream S11 heats stream L1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, which are depleted of carbon dioxide and enriched in hexane-1,6-diamine. From the heating means EH1, a cooled stream S12 is obtained. The liquid stream L11 is then sent to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E1 provides a vapor stream V2 (V) and a liquid stream L11 (L2), the liquid stream L2 being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH2 provides a cooled stream WL2. The vapor stream V2 (V) obtained from the evaporator E2 is used as a heat medium in a heat exchanger H1 to preheat the liquid stream L1, thereby providing a cooled stream VL. [Figure 17]17 is a schematic diagram of a method according to the present invention, comprising a three-stage evaporation of stream L1 and further comprising preheating of stream L1. According to FIG. 17, an aqueous liquid stream L1 containing at least one hexane-1,6-diamine species, including at least one carbon dioxide derivative of hexane-1,6-diamine, passes through a heat exchanger H1, and the heated liquid stream L1 is sent to a first evaporator E1 equipped with a heating means EH1. Through the heating means EH1, a heat carrier stream S11 heats stream L1. From the evaporator E1, a vapor stream V1 and a liquid stream L11 are obtained, which are depleted of carbon dioxide and enriched in hexane-1,6-diamine. From the heating means EH1, a cooled stream S12 is obtained. The liquid stream L11 is then sent to a second evaporator E2 equipped with a heating means EH2. The vapor stream V1 obtained from the first evaporator E1 passes through the heating means EH2 as a heat carrier for heating the liquid stream L11. The evaporator E2 produces a vapor stream V2 and a liquid stream L12, the latter being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH2 produces a cooled stream WL2. The liquid stream L12 is then sent to a third evaporator E3 equipped with a heating means EH3. The vapor stream V2 from the second evaporator E2 passes through the heating means EH3 as a heat medium for heating the liquid stream L12. The evaporator E3 produces a vapor stream V3(V) and a liquid stream L13(L2), the former being depleted of carbon dioxide and enriched in hexane-1,6-diamine. The heating means EH3 produces a cooled stream WL3. The vapor stream V3(V) from the evaporator E3 is used as a heat medium in a heat exchanger H1 to preheat the liquid stream L1, thereby producing a cooled stream VL. [Figure 18] 18 is a representation of the results obtained from Example 2.1. In the graph of Figure 18, the temperature of the evaporator E1 is plotted on the x-axis, while the heat energy (kWh) per kg of free HMDA is plotted on the y-axis. The following curves are shown, attributable to the following percentages of HMDA: [Table 1] [Figure 19]19 is a representation of the results obtained from Examples 2.2 and 2.3. In the graph of Figure 19, the temperature of evaporator E1 is plotted on the x-axis, while the y-axis plots the heat energy (kWh) per kg of free HMDA (upper graph) and the amount of free HMDA obtained per kg of HMDA species in L1 (lower graph). The following curves are shown, attributing the following percentages of HMDA: [Table 2] [Figure 20] 20 is a representation of the results obtained from Example 2.4. In the graph of Figure 20, the temperature of evaporator E1 is plotted on the x-axis, while the y-axis plots the heat energy (kWh) per kg of free HMDA (upper graph) and the amount of free HMDA obtained per kg of HMDA species in L1 (lower graph). The following curves are shown, attributing the following percentages of HMDA: [Table 3] [Figure 21] 21 is a representation of the results obtained from Example 2.5. In the graph of FIG. 21, the temperature of evaporator E1 is plotted on the x-axis, while the specific energy demand (kWh) per kg of free HMDA is plotted on the y-axis. The following curves are shown, attributable to the following percentages of HMDA: [Table 4] DETAILED DESCRIPTION OF THE INVENTION

[0128] Example 1. Determination of thermal stability of HMDA aqueous solutions The thermal stability of two aqueous solutions, one containing CO2-free 20 wt% HMDA and the other containing CO2-loaded 20 wt% HMDA, was determined by dynamic differential scanning calorimetry (DSC). The CO2-free solution exhibited an exothermic decomposition reaction with an energy release of over 70 J / g at 465 °C. The CO2-loaded HMDA solution (20 wt% HMDA, CO2 loading of 1.0 mol CO2 per mole of HMDA) exhibited lower thermal stability, exhibiting an exothermic reaction with an energy release of 50 J / g already at 200 °C (the starting temperature). Because this release is an endothermic process, we were able to rule out its origin as a CO2 release. Therefore, we can conclude that CO2-loaded HMDA in aqueous solution is thermally unstable, starting at 200 °C.

[0129] 2. Example based on process simulation Prior to the process simulation, a thermodynamic model capable of describing the phase equilibrium (vapor-liquid equilibrium) of the system CO2-HMDA-H2O was developed. The following chemical reactions in the liquid phase were considered: [Table 5]

[0130] For all process simulations, we assumed that all reactions proceed sufficiently fast during stripping and can therefore be considered equilibrium reactions. The model is based on gas solubility measurements at temperatures between 30 and 60 °C obtained from the literature (Mondal et al., Fluid Phase Equilibria, 402 (2015), pp. 102-112), supplemented by gas solubility measurements performed by the present inventors up to 160 °C. Furthermore, to account for the volatility of HMDA in addition to the dissolved amount of CO2, we also considered the vapor-liquid equilibrium of the binary system H2O-HMDA. In this context, we used literature data (Rousseau et al., AIChE Symp. Ser. (1989) 85 (271), pp. 73-78). To account for nonidealities, we used the liquid-phase activity coefficient v, G, as formulated by Edwards and Pitzer. E The cubic equation of state by Redlich-Kwong-Soave was used to describe the gas phase using the -Modell (Edwards et al., AIChE J. (1975) 21(29), pp. 248-259). Based on this, process simulations were used to describe the separation of CO2 and the preparation of CO2-free HMDA aqueous solutions.

[0131] For all process simulations described below, the following liquid aqueous feed stream L1 was used: a 10 wt % aqueous solution of HMDA on a CO2 free basis, with a temperature of 30°C, adjusted to pH 8.5 using CO2.

[0132] 2.1 CO2 separation using a stripping column According to this Example 2.1, CO2 contained in feed stream L1 was separated using a stripping column configured as shown in Figure 4. The stripping gas used was stripping steam, prepared in situ during stripping, i.e., at the bottom of the stripping column, by evaporating a portion of the aqueous HDA solution. Due to the high boiling point of HMDA, essentially only water evaporated. At the top of the stripping column, preheated stream L1 was sent to the column, passing countercurrently with the stripping steam. Preheating of L1 was achieved by heat integration, whereby the hot CO2-depleted HMDA solution, exiting E1 as stream L3, transfers heat to the cold HMDA stream L1 in H1. At the top of the column, a vapor stream V containing H2O, CO2, and traces of HMDA was obtained. This stream V was sent to condenser C1, where H2O and HMDA were condensed, resulting in stream L1. V CO2 exits C1 as a gas (flow V V For the purposes of the simulation, the condenser C1 was operated at an outlet temperature of 45°C.

[0133] As for the stripping column, a mass-transfer-based model was used, with a 2-inch packing (1 inch = 2.54 cm) and a packing height of 10 m. The column diameter was designed to be 65% of the column flood point. The pressure at the top of the column was varied between 0.6 bar and 9 bar, corresponding to evaporator temperatures of 88 °C and 175 °C. The proportion of free HMDA relative to the amount of HMDA contained in L1 was specified to be between 50 and 97%. Therefore, using this stripping column, it was possible to significantly increase the yield of free HMDA. Furthermore, it was found that the energy required to obtain free HMDA decreased with increasing temperature / pressure in the stripping column. Thus, for example, in the case of 97% free HMDA, the optimal temperature for evaporator E1 was found to be at least, and preferably above, 150 °C. In this context, reference is made to Figure 18, where the simulation results are shown.

[0134] 2.2 CO2 separation using a stripping column According to this example 2.2, the CO contained in the feed stream L1 was separated using a stripping column configured as shown in Figure 5. Compared to the stripping column described in example 2.1, this configuration is modified, allowing the method goals, namely increasing the HMDA content by evaporation and stripping the CO2, to be achieved. The modifications essentially relate to the heat integration concept involved and to the fact that the condensate obtained from the condenser C1 is not recycled to the stripping column.

[0135] According to this heat integration concept, the cold feed stream L1 is first brought to a higher temperature using a vapor stream V containing HO, CO and traces of HMDA. The heated stream L1 thus obtained is then brought to the final temperature in a second heating step using a hot stream L3 obtained from an evaporator E1, this hot stream L3 being depleted in CO and containing free HMDA. Once in the column, stream L1, which passes countercurrently to the stripping vapor through the column, is subjected to evaporation, resulting in an overhead stream V containing CO, HO and traces of HMDA.

[0136] As far as the stripping column is concerned, it was modeled using a mass-transfer-based model with a 2-inch packing (1 inch = 2.54 cm) and a packing height of 10 m. The column diameter was designed at 65% of the column flood point. The pressure at the top of the column was varied between 0.2 bar and 9 bar, corresponding to evaporator temperatures of 65 °C and 178 °C. The degree of evaporation was determined by the water content of the concentrated CO2-depleted HMDA solution (stream L2). Water content values ​​of 80 wt%, 70 wt%, and 60 wt% for L2 were selected. Although the required energy input was higher than that according to Example 2.4 (three-stage evaporation), higher yields of free HMDA were obtained. According to Example 2.4, a maximum of 88% free HMDA was obtained at a water content of 80 wt%, while according to Example 2.2, 98% free HMDA was obtained at a water content of 80 wt%. As shown in Figure 19, as the pressure / temperature in the stripping column increases, an increasing portion of HMDA is vaporized and removed with the condensate.

[0137] 2.3 CO2 separation using a stripping column According to this Example 2.3, the configuration according to Example 2.2 was augmented by a backwash section at the top of the stripping column. See the respective Figure 6. In particular, an additional packing bed was installed above the feed point of the column where L1 is introduced. For the modeling of the column, a packing height of 3.5 m was selected for the other packing sections with 2-inch packing. The condensate stream L VL The partial flow L VL1 is sent to this backwash section. A reflux ratio of 1:10 was selected.

[0138] This process configuration allowed for a reduction in the HMDA content in the condensate and therefore the overall yield of free HMDA. For the configuration according to Example 2.2, which does not include a backwash section, there is an optimum temperature range in terms of energy input and free HMDA yield. See Figure 19, where the results are shown.

[0139] 2.4 CO2 Separation Using Multistage Evaporation According to this Example 2.4, evaporation was carried out using a three-stage evaporation with heat integration, as shown in Figure 17. According to this process configuration, only the evaporator E1 was used to generate external energy (external steam (flow S 11 ) and so on), while evaporators E2 and E3 are heated by streams V1 and V2, respectively. For this, the temperature and pressure of evaporator E2 must be lower than E1, respectively, and the temperature and pressure of evaporator E3 must be lower than E2, respectively. Furthermore, feed stream L1 is preheated in heat exchanger H1 using stream V3 = V. A value of 10 K was specified as the driving temperature difference between the condenser and the evaporator. The temperature of evaporator E1 is set, and S 11 The temperatures of evaporators E2 and E3 were optimized to minimize the external energy supplied to E1 via the evaporator E1. For evaporator E1, the temperature was varied from 110 to 200 °C, and the water contents of the CO2-depleted concentrated HMDA solution were specified as 60 wt%, 70 wt%, and 80 wt%.

[0140] The results are shown in Figure 20. The crucial parameter is the amount of HMDA present as free HMDA after CO2 separation. Other HMDA species, such as protonated HMDA or carbamate, cannot be extracted in subsequent extraction stages, which allow only free HMDA to be extracted into the organic phase. As shown in Figure 20, for a water content of 80 wt.%, the energy input was 2 kWh per kg of free HMDA. Surprisingly, a yield of 88% of free HMDA was found. In this context, it should be noted that for each single-stage evaporation, the energy input was as high as 6.2 kWh per kg of free HMDA, with a yield of only 74%.

[0141] In general, it was found that at higher temperatures and at temperatures of at least 130°C, the specific energy demand of E1 is minimized, and at temperatures of at least 190°C, a slight increase in said energy demand is observed.

[0142] 2.5 CO2 Separation Using Stripping and Evaporation According to a further configuration of the process of the invention shown in Figure 11, the advantages of stripping and evaporation are combined. In this method, a stripping column is essentially used to remove CO2, and in a downstream evaporation stage of E2, which operates at a lower pressure compared to the upstream stripping column, the excess steam obtained at V at the top of the stripping column is used to further evaporate the water contained in L3. According to the preferred embodiment shown in Figure 11, the respective obtained streams V L3 is further used to preheat the feed stream L1.

[0143] This process configuration therefore combines the advantages of separating CO in a stripping column and concentrating the bottoms stream obtained from said column with respect to its content of free HMDA. The results are shown in Figure 21.

[0144] References: US Patent No. 2017 / 0369913 (A1) [Explanation of symbols]

[0145] V Vapor flow L liquid aqueous flow VL water vapor flow T temperature E evaporator H heat exchanger C condenser K compressor S style W style E j Evaporation device E Hj heating means V K Compressible flow VK(l) liquid phase VK(g) gas phase

Claims

1. a liquid aqueous stream L comprising at least one hexane-1,6-diamine species comprising at least one carbon dioxide derivative of hexane-1,6-diamine; １ A method for extracting carbon dioxide from (i) Carbon dioxide loading c Ｌ１ The liquid aqueous flow L １ providing a Ｌ１ Ga n Ｌ１ (CO ２ ) / n Ｌ１ (HMDA), n Ｌ１ (CO ２ ) but L １ is the molar amount of carbon dioxide contained in said at least one carbon dioxide derivative of hexane-1,6-diamine in Ｌ１ (HMDA) is L １ c is the molar amount of the at least one hexane-1,6-diamine species in Ｌ１ is greater than or equal to 0.5 and less than or equal to 2.5, and the liquid aqueous stream L １ is lower than the temperature T according to (ii). Ｌ１ 2. The steps of (ii) the liquid aqueous stream L provided according to (i) １ is heated to a temperature T of 90° C. or higher at a pressure p of 0.5 bar (abs) or higher to obtain a vapor stream V containing carbon dioxide, and a carbon dioxide loading c Ｌ２ Liquid aqueous flow L ２ obtaining a step of Ｌ２ Ga n Ｌ２ (CO ２ ) / n Ｌ２ (HMDA), n Ｌ２ (CO ２ ) but L ２ is the molar amount of carbon dioxide contained in the at least one carbon dioxide derivative of hexane-1,6-diamine in Ｌ２ (HMDA) is L ２ c is the molar amount of the at least one hexane-1,6-diamine species in Ｌ２ is less than or equal to 0.

1.

2. 80 to 100 mol %, preferably 90 to 100 mol %, more preferably 95 to 100 mol % of said at least one carbon dioxide derivative of hexane-1,6-diamine consists of one or more of hexamethylene-1,6-carbamate, hexamethylene-1,6-dicarbamate, hexamethylene-1,6-carbamate zwitterion, hexamethylene-1,6-carbonate, hexamethylene-1,6-bicarbonate, and hexamethylene-1,6-bis-bicarbonate; 2. The method of claim 1, wherein preferably 90 to 100 mol %, more preferably 95 to 100 mol %, more preferably 98 to 100 mol % of the at least one hexane-1,6-diamine species consists of the at least one carbon dioxide derivative of hexane-1,6-diamine, and optionally the free base of hexane-1,6-diamine.

3. 0.6≦c Ｌ１ ≦2.0, preferably 0.7≦c Ｌ１ 3. The method of claim 1 or 2, wherein the ρ is ≦1.

6.

4. the liquid aqueous stream L provided according to (i) １ 90 to 100% by weight, preferably 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight of the compound of the present invention is composed of water, said at least carbon dioxide derivative of hexane-1,6-diamine, and optionally hexane-1,6-diamine free base; the liquid aqueous stream L provided according to (i) １ But, L １ 4. The method according to any one of claims 1 to 3, wherein the solution has a pH in the range of from 6 to 10, more preferably in the range of from 7 to 9.5, more preferably in the range of from 7.5 to 9, at a temperature of from 25°C.

5. 10℃≦T Ｌ１ <T, preferably 15°C ≤ T Ｌ１ <T, more preferably 20°C ≤ T Ｌ１ <T, 5. The method according to any one of claims 1 to 4, wherein the temperature T according to (ii) is preferably in the range of from 90 to 190°C, more preferably in the range of from 100 to 180°C, more preferably in the range of from 110 to 170°C.

6. c Ｌ２ ≦0.08, preferably c Ｌ２ ≦0.06, more preferably c Ｌ２ ≦0.04, more preferably c Ｌ２ 6. The method of any one of claims 1 to 5, wherein the ρ is ≦0.

02.

7. Step (ii) is carried out in a stripping column using a stripping medium, and the liquid aqueous stream L from (i) １ supplying the liquid aqueous stream L １ to said stripping column, wherein (ii) (ii.1) the liquid aqueous stream L fed according to (i) in the stripping column １ to a temperature T of at least 90° C. at a pressure p of at least 0.5 bar (abs), (ii.2) at the top of the stripping column, a temperature T Ｖ obtaining a vapor stream V comprising carbon dioxide, and removing said vapor stream V from the top of said stripping column; (ii.3) Temperature T Ｌ２ and the liquid aqueous stream L comprising hexane-1,6-diamine free base. ２ is obtained at the bottom of the stripping column, and the liquid aqueous stream L ２ from the bottom of the stripping column; The method further comprises: (iii.1) (ii.3) ２ Evaporator E １ and evaporates at a temperature T ＶＬ２ a water vapor flow V Ｌ２ and temperature T Ｌ３ an aqueous liquid stream L having ３ preferably T ＶＬ２ =T Ｌ３ Steps to get (iii.2) The water vapor stream V obtained according to (iii.1) Ｌ２ to the bottom section of the stripping column; the stripping medium preferably comprises steam, more preferably 90 to 100 wt. %, more preferably 95 to 100 wt. %, more preferably 99 to 100 wt. % of the stripping medium consists of steam; The vapor is passed through the liquid aqueous stream L in the stripping column. １ The method according to any one of claims 1 to 6, wherein the reaction mixture is at least partially, more preferably completely, obtained in situ in the stripping column by heating to a temperature T.

8. (iii.3) The aqueous liquid stream L obtained according to (iii.1) ３ Heat exchanger H １ Pass through T Ｌ４ <T Ｌ３ Temperature T Ｌ４ Flow L having ４ obtaining a step of (iii.4) Temperature T Ｌ１０ the liquid aqueous stream L having １ is passed through the heat exchanger H before being fed to the stripping column. １ Pass through T Ｌ１ >T Ｌ１０ Temperature T Ｌ１ the liquid aqueous stream L having １ and further comprising the step of obtaining According to (iii.4), ΔT Ｈ１ =T Ｌ１０ -T Ｌ４ and preferably ΔT Ｈ１ ≦20 K, more preferably ΔT Ｈ１ ≦10 K, more preferably ΔT Ｈ１ ≦5K; The method of claim 7.

9. (ii.2) wherein the vapor stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, and (iv.1) The vapor stream V obtained according to (ii.2) is fed to a condenser C １ condensed at a temperature T ＬＶ A liquid flow L having Ｖ and further obtaining a carbon dioxide-containing, water-depleted vapor stream V Ｖ and further comprising the step of obtaining The method preferably comprises: (iv.2) The liquid stream L obtained according to (iv.1) Ｖ Two flows L Ｖ１ and L Ｖ２ and the flow L Ｖ１ to the top section of the stripping column; 9. The process according to claim 7 or 8, wherein the reflux ratio is preferably in the range of from 0.01:1 to 1:1, more preferably in the range of from 0.03:1 to 0.3:1, more preferably in the range of from 0.05:1 to 0.2:

1.

10. wherein the vapor stream V obtained according to (ii.2) further comprises water in addition to carbon dioxide, and the process further comprises: (iv.0) (ii.2) is passed through a heat exchanger H ２ and passes through it at a temperature of T ＨＶＬ <T Ｖ obtaining a partially condensed stream VL having (iv.1) The flow VL obtained according to (iv.0) is passed through a condenser C １ condensed at a temperature T ＬＶ A liquid flow L having Ｖ and a vapor stream V containing carbon dioxide and depleted in water is obtained. Ｖ and further comprising the step of obtaining The method may be performed at a temperature T Ｌ１００ the liquid aqueous stream L having １ to the heat exchanger H according to (iii.4) １ before passing through the heat exchanger H according to (iv.0) ２ Pass through T Ｌ１０ >T Ｌ１００ Temperature T Ｌ１０ the liquid aqueous stream L having １ and further comprising the step of obtaining ΔT Ｈ２ =T Ｌ１００ -T ＨＶＬ and preferably ΔT Ｈ２ ≦20 K, more preferably ΔT Ｈ１ ≦10 K, more preferably ΔT Ｈ１ 9. The method of claim 7 or 8, wherein ≦5 K.

11. After (iv.0) and before (iv.1), (iv.2) The flow VL obtained according to (iv.0) is divided into two flows VL １ and VL ２ and the flow VL １ is returned to the top section of the stripping column, and the stream VL ２ as the flow VL according to (iv.1), and as the flow C １ and further comprising subjecting the mixture to condensation at 11. The process of claim 10, wherein the reflux ratio is preferably in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, more preferably in the range of 0.05:1 to 0.2:

1.

12. (v.1) Temperature T ＶＫ and a vapor stream V containing carbon dioxide and preferably water, preferably having the same chemical composition as said vapor stream V. Ｋ from the top of the stripping column; (v.2) the stream V withdrawn from the top of the stripping column according to (v.1); Ｋ Compressor K １ Pass through T ＣＶＫ >T ＶＫ Temperature T ＣＶＫ Compressible flow V Ｋ obtaining a step of (v.3) the compressed flow V Ｋ Evaporator E by (iii.1) using １ The liquid phase V Ｋ (l) and optionally gas phase V Ｋ (g) a cooled compressed stream V Ｋ obtaining a step of (v.4) Preferably, the liquid phase V obtained according to (v.3) Ｋ (l), or a portion thereof, to the top section of the stripping column. The method according to any one of claims 7 to 11.

13. (iii.3) The vapor stream V obtained according to (ii.2) is fed to an evaporator E ２ and passes through it at a temperature of T ＥＶ <T Ｖ obtaining said stream V having (iii.4) The aqueous liquid stream L obtained according to (iii.1) ３ (iii.3) according to the evaporator E ２ and evaporated at T ＶＬ３ =T ＬＬ３ At temperature T ＶＬ３ a water vapor flow V Ｌ３ and temperature T ＬＬ３ an aqueous liquid stream L having Ｌ３ and further comprising the step of obtaining The method preferably comprises: (iii.5) The water vapor stream V obtained according to (iii.4) Ｌ３ Heat exchanger H １ Pass through T ＶＬ３Ｈ <T ＶＬ３ Temperature T ＶＬ３Ｈ an aqueous vapor stream V having Ｌ３Ｈ obtaining a step of (iii.4) Temperature T Ｌ１０ the liquid aqueous stream L having １ is passed through the heat exchanger H before being fed to the stripping column. １ Pass through T Ｌ１ >T Ｌ１０ Temperature T Ｌ１ the liquid aqueous stream L having １ and further comprising the step of obtaining The water vapor stream V obtained according to (iii.5) Ｌ３Ｈ preferably in a condenser C ２ 8. The method of claim 7, wherein the aqueous stream is condensed with 2000 kJ / kg of ethanol to obtain a liquid aqueous stream.

14. wherein the vapor stream V obtained according to (iii.3) further comprises water in addition to carbon dioxide, and (iv.1) The vapor stream V obtained according to (iii.3) is fed to a condenser C １ condensed at a temperature T ＬＶ A liquid flow L having Ｖ and further obtaining a carbon dioxide-containing, water-depleted vapor stream V Ｖ and further comprising the step of obtaining The method preferably comprises: (iv.2) The liquid stream L obtained according to (iv.1) Ｖ Two flows L Ｖ１ and L Ｖ２ and the flow L Ｖ１ to the top section of the stripping column; 14. The process of claim 13, wherein the reflux ratio is preferably in the range of 0.01:1 to 1:1, more preferably in the range of 0.03:1 to 0.3:1, more preferably in the range of 0.05:1 to 0.2:

1.

15. Step (ii) comprises n series-connected evaporators E ｊ , j=1...n, and the evaporation unit E ｊ However, heating means E Ｈｊ and an evaporation device E ｊ＋１ However, evaporator E ｊ and (i) disposing the liquid aqueous stream L １ supplying the liquid aqueous stream L １ The evaporation device E １ including supplying For j=1...n, (ii) is The evaporation device E ｊ The liquid aqueous stream being supplied to the evaporator E ｊ At pressure p ｊ At temperature T ｊ Heat to a temperature T Ｖｊ and a vapor stream V containing carbon dioxide. ｊ and the vapor flow V ｊ The evaporation device E ｊ and the liquid aqueous stream L １ｊ and the temperature T Ｌ１ｊ and c Ｌ１ｊ Ga n Ｌ１ｊ (CO ２ ) / n Ｌ１ｊ (HMDA), n Ｌ１ｊ (CO ２ ) is L １ｊ n is the molar amount of carbon dioxide contained in at least one carbon dioxide derivative of hexane-1,6-diamine in Ｌ１ｊ (HMDA) is L １ｊ carbon dioxide loading c, which is the molar amount of at least one hexane-1,6-diamine species in Ｌ１ｊ The liquid aqueous flow L １ｊ obtain the liquid aqueous stream L １ｊ The evaporation device E ｊ and obtaining from E ｊ The liquid aqueous stream L taken from １ｊ The evaporation device E ｊ＋１ for evaporation, and the vapor flow V Ｌｊ The evaporation device E ｊ＋１ The heating means E Ｈｊ＋１ Pass through the flow W Ｌｊ＋１ The heating means E Ｈｊ＋１ and removing the When j=n, (ii) becomes The evaporation device E ｎ The liquid aqueous stream being supplied to the evaporator E ｎ At pressure p ｎ At temperature T ｎ and the vapor flow V reaches a temperature T Ｖ and a vapor stream V containing carbon dioxide. ｎ =V, and the vapor flow V is transferred to the evaporator E ｎ and the liquid aqueous stream L ２ is the temperature T Ｌ２ and carbon dioxide loading c Ｌ２ Liquid aqueous flow L １ｎ =L ２ obtain the liquid aqueous stream L ２ The evaporation device E ｎ and removing the One parameter pair (T ｊ ;p ｊ ) is the parameter pair (T; p) as defined in claim 1 with T ≥ 90°C and pressure p ≥ 0.5 bar (abs), The method according to any one of claims 1 to 6, wherein preferably n=7, more preferably n=6, more preferably n=5, more preferably n=4, more preferably n=3 or n=2.

16. The parameter pair (T １ ;p １ ) is the parameter pair (T; p) as defined in claim 1 at a temperature T ≥ 90°C and a pressure p ≥ 0.5 bar (abs), 16. The method of claim 15, wherein T is preferably in the range of from 90 to 190°C, more preferably in the range of from 110 to 190°C, more preferably in the range of from 130 to 190°C.

17. For j=1...n-1, p ｊ＋１ <p ｊ c Ｌ１ｊ＋１ <c Ｌ１ｊ and T ｊ＋１ <T ｊ and for j=1...n-1, ΔT Ｅｊ＋１ =T Ｖｊ -T Ｌ１ｊ＋１ The method according to claim 15 or 16, wherein the temperature is preferably in the range of 5 to 10 K.

18. the vapor stream V further comprises water in addition to carbon dioxide, and the method further comprises: condensing the vapor stream V into a condenser C １ condensed at a temperature T ＬＶ A liquid flow L having Ｖ and further comprising a vapor stream V containing carbon dioxide and depleted in water. Ｖ The method of any one of claims 15 to 17, further comprising the step of obtaining:

19. The vapor stream V obtained according to (ii.2) is passed through a heat exchanger H １ and passes through it at a temperature of T ＶＬ <T Ｖ and obtaining an optionally partially condensed stream VL having a temperature T Ｌ１０ the liquid aqueous stream L having １ to the heat exchanger H １ Pass through T Ｌ１ >T Ｌ１０ Temperature T Ｌ１ the liquid aqueous stream L having １ The method of any one of claims 15 to 17, further comprising the step of obtaining:

20. The liquid aqueous stream L １ can be obtained or is obtained by a fermentation process, said stream L ２ or the downstream stream obtained therefrom is subjected to extraction, L ２ The downstream flow obtained from the flow L as defined in claim 7 ３ , the flow L as defined in claim 8 ４ or the flow L as defined in claim 13 Ｌ３ The method according to any one of claims 1 to 19, wherein

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