https://doi.org/10.1016/j.seppur.2020.118193
“In terms of pure chemical activity and reaction, shifting from an aqueous to a water-lean solvent seems to consistently depress the solubility of CO2, leading to a shift in equilibrium. This can be seen in practically all the experimental vapor–liquid equilibrium data compiled in Table 2, Table 3, Table 4, except when explicitly stated that the authors suspect the presence of a side-reaction involving the diluent itself.”
Table 2. Publications that show VLE data for water-lean solvents with MEA.
| Reference | Diluents | Conditions and remarks |
|---|---|---|
| [34] | NMP, PC, TMS | C = 15% wt. MEA and T = 25, 100 °C for water-free NMP shown in graph form. For other solvents, authors report equilibrium constants instead of raw data. |
| [22] | NMP, PC | Water-free C = 5.1, 14.3 %wt. MEA T = 25, 50 °C |
| [83] | NMP | Water-free C = 15 %wt. MEA T = 25, 50, 100 °C |
| [24], [84] | TMS | Water-free C = 15, 30 %wt. MEA T = 30, 50, 100 °C |
| [57], [85] | MEG, PEG400 | D = 15.3, 42.3 %wt. diluent C = 15.3 %wt. MEA T = 40, 60 °C |
| [31] | Various | C = 2.5 mol∙l−1 MEA and T = 20 °C for a huge array of water-free diluents shown in graph form. C = 2.5 mol∙l−1 MEA and T = − 50, −30, −10, 0, 10, 20 °C for water-free methanol shown in graph form. |
| [86] | TEG | Water-free C = 0.1, 0.2, 0.3, 0.5 mol∙l−1 MEA T = 30, 40, 50, 60,70, 80 °C |
| [87] | Benzoic acid* | D = 1, 2, 5 %wt. diluent C = 14, 13, 10 %wt. MEA T = 40 °C |
| [73] | DEGDME | Water-free C = 15, 30, 45 %wt. MEA T = 20, 30, 40, 50, 60 °C |
| [26] | GLY | D = 5, 10, 15, 20 %wt. diluent C = 30 %wt. MEA T = 40, 50, 60 °C |
| [88] | MEG | D = 1/1 MEG/water mass basis and water-free C = 30 %wt. MEA T = 40, 80 °C |
| [89] | GLY | The authors have designed their experiments so as to parametrize a model by using a central composite experimental design matrix. However, the most consistent set of data is at the conditions below: D = 2, 4, 6 mol∙l−1 diluent C = 2.5 mol∙l−1 MEA T = 40 °C |
| [90] | MEG, MeOH, NMP | Water-free C = 10, 20, 30 %wt. MEA T = 30 °C |
| [18] | CARB, NMP | D = 1/3 in carbitol/water mass basis and 19/1, 3/1, 1/3 in NMP/water mass basis C = 7 mol MEA∙kg solvent−1 T = 40 °C |
| [80] | 2ME | Water-free C = 5 mol∙l−1 MEA T = 40, 60, 80, 100, 120 °C |
| [91] | 2EE, 2ME | Water-free C = 5 mol∙l−1 MEA T = 40, 100 °C |
| [92] | L92 | D = 60 %wt. diluent C = 10 %wt. MEA T = 30 °C |
| [66] | 1MIMI, DMSO, MEG, NMP, TMS | D = 3/1 in diluent/water mass basis C = 5 mol MEA∙kg solvent−1 T = 40 °C |
| [59] | ACE, CC5, FA, GBL, MEG, MeOH, NMP, THFA, TMS | A specific analysis of aqueous THFA solutions was performed at 40 °C with different THFA-MEA-water compositions. However, the most consistent set of data is at the conditions below: Water free C = 30 %wt. MEA T = 40, 80, 120 °C |
*Benzoic acid is clearly not a proposed diluent for water-lean solvent formulation. Instead, the authors [87] proposed the addition of an acid to the rich amine for releasing CO2 at lower reboiler duty costs. The MEA-benzoate precipitates upon reaction and can then be mechanically separated, though at which cost the amine itself is recovered is not addressed. In a later publication they proposed oxalic acid instead of benzoic acid [93].
Table 3. Publications that show VLE data for water-lean solvents with DEA, MDEA, AMP.
| Data for water-lean solvents with DEA | ||
|---|---|---|
| Reference | Diluents | Conditions and remarks |
| [22] | NMP | Water-free C = 5.1, 14.3 %wt. DEA T = 25, 50 °C |
| [62], [94] | MEG | D = water-free, then approximately 20, 40, 60 and 80 %wt. diluent C = approximately 1, 2 mol∙l−1 DEA T = 25 °C |
| [24] | TMS | Water-free C = 15 %wt. DEA T = 30 °C |
| [83] | NMP | Water-free C = 15, 30 %wt. DEA T = 25, 50, 100 °C |
| [72] | MeOH | D = 10, 20, 30 %wt. diluent C = 30 %wt. DEA T = 25 °C |
| [95] | MeOH | D = 20, 40 %wt. diluent C = 20, 40 %wt. DEA T = 50, 60, 80, 100, 120 °C |
| [96] | PEG200 | Water-free C = 30 %wt. DEA T = 40, 80, 120 °C |
| Data for water-lean solvents with MDEA | ||
| Reference | Diluents | Conditions and remarks |
| [60] | TMS | The authors identify the formation of a second liquid phase at high CO2 loadings. D = 30.5 %wt. diluent C = 20.9 %wt. MDEA T = 40, 100 °C |
| [97] | MeOH | D = water-free and 40 %wt. diluent C = 40, 50 %wt. MDEA T = 40, 100 °C |
| [98] | TEGMME | The authors identify the formation of a second liquid phase at high CO2 loadings. D = water-free and 40 %wt. diluent C = 40, 50 %wt. MDEA T = 40, 100 °C |
| [99] | EtOH | The authors believe that nonaqueous MDEA can only act as a physical solvent. Therefore, they report Henry’s coefficients. Water-free C = 10, 20, 30, 50, 60, 70, 85, 100 %wt. MDEA T = 20 °C |
| [100] | MEG | D = 60, 65, 70 %wt. diluent C = 30 %wt. MDEA T = 25, 40, 60, 90 °C |
| [78] | ACEA, DACE, EC | D = 5 %wt. diluent C = 48 %wt. MDEA T = 25, 30 °C |
| [101] | PC | The solvent developed by the authors has 0.05 %wt. of undisclosed activators. D = 91.95 %wt. diluent C = 6 %wt. MDEA T = 25 °C |
| [102] | TMS | D = 0.36, 0.86, 1.36 mol∙l−1 diluent C = 3.0, 2.5, 2.0 mol∙l−1 MDEA T = 40, 55, 70 °C |
| [103] | NMP | The authors identify the formation of a second liquid phase at high CO2 loadings. D = 50 %wt. diluent C = 40 %wt. MDEA T = 0, 25, 50, 75, 100, 125, 150 °C |
| [96] | PEG200 | Water-free C = 30 %wt. MDEA T = 40, 80, 120 °C |
| [46] | EtOH | Water-free C = 15 %wt. MDEA T = 40 °C |
| [66] | 1MIMI, DMSO, MEG, NMP, TMS | D = 1/1 in diluent/water mass basis C = 3.5 mol MDEA∙kg solvent−1 T = 40 °C |
| Data for water-lean solvents with AMP | ||
| Reference | Diluents | Conditions and remarks |
| [79], [104] | TMS | D = 32.2 %wt. diluent C = 16.5 %wt. AMP T = 40, 100 °C |
| [105] | TMS | D = 19.4, 27.7, 32.2, 41.2 %wt. diluent C = 30.6, 22.3, 16.5, 8.2 %wt. AMP T = 40, 60, 80, 100 °C |
| [106] | DEG, TEG | Water-free C = 0.2, 0.4, 0.6 mol∙l−1 AMP T = 30, 45, 60, 80 °C |
| [81] | MEG | Water-free C = 0.4, 0.6, 1.0 mol∙l−1 AMP T = 30, 45, 60, 80 °C |
| [107], [108] | NMP, TEGDME | The precipitation of AMP-carbamate is observed for both diluents. Water-free C = 15, 25 %wt. AMP T = 25, 50 °C |
| [109] | NMP | Precipitation was observed at pressures above 3 bars in some of the solvents. D = 41.2, 32.2, 27.7, 19.4 %wt. diluent C = 8.2, 16.5, 22.3, 30.6 %wt. AMP T = 40, 60, 80 °C |
| [32] | 1MIMI, 3DMAPN, 4H, CH, DMSO, PC, 1PeOH | Precipitation was observed at 25 °C in all diluents minus 1MIMI and CH (which is solid at that temperature). Data at 25 °C is not given for CH. Data at 40 °C is not given for systems with 1MIMI, 4H and PC. Water-free C = 25 %wt. AMP T = 25, 40 °C |
| [110] | MeOH | D = 41.2, 32.2, 27.7, 19.4 %wt. diluent C = 8.2, 16.5, 22.3, 30.6 %wt. AMP T = 40, 60, 80 °C |
Table 4. Publications that show VLE data for water-lean solvents with other amines or blends.
| Reference | Amines | Diluents | Remarks |
|---|---|---|---|
| [25] | DIPA | TMS | D = 40 %wt. diluent C = 40 %wt. DIPA T = 40, 100 °C |
| [34] | DGA | TMS, NMP, PC | Authors report equilibrium constants instead of raw data. |
| [111] | 2PDE | TMS | D = 10 %wt. diluent C = 55 %wt. amine T = 40, 100 °C |
| [112] | TEA | PC | D = 2, 5, 10 %wt. diluent C = 98, 95, 90 %wt. TEA T = 10, 40 °C |
| [102] | MDEA/PZ | TMS | D = 0.84, 0.68, 0.43 mol∙l−1 diluent C = 1.68/0.84, 2.0/0.68, 2.5/0.43 MDEA/PZ in mol∙l−1 T = 40, 55, 70 °C |
| [113] | AEEA | BP, DEG, TEG | The data for diluents DEG and TEG is provided only at 40 °C. Water-free C = 30 %wt. AEEA T = 30, 40, 50 °C |
| [96] | DGA | PEG200 | Water-free C = 30 %wt. DGA T = 40, 80, 120 °C |
| [114] | EMEA | 1BuOH, BP, DEEA, DEG, PEG200, TEG | Water-free C = 40 %wt. EMEA T = 40 °C |
| [46] | EMEA/MDEA | EtOH | D = 60, 65, 70, 75 %wt. diluent C = 25/15, 20/15, 15/15, 10/15 EMEA/MDEA in %wt. T = 40 °C |
| [115] | MDEA/PZ | TMS | D = 10 %wt. diluent C = 42/8, 45/5, 48/2 MDEA/PZ in %wt. T = 40, 50, 60 °C |
| [116] | 2FPEA | OFP | Water-free C = undisclosed T = 30, 40, 60, 80, 120 °C |
| [117] | AMP/PZ | 2EE | D = 2.5 mol∙l−1 diluent C = 2.5/0.6 AMP/PZ in mol∙l−1 T = 30 °C |
| [118], [119] | AMP/DMHDA | TEG | D = 2.0 mol∙l−1 diluent C = 2.5/0.5 AMP/DMHDA in mol∙l−1 T = 30 °C |
| [66] | 2MPZ | 1MIMI, DMSO, MEG, NMP, TMS | D = 1/1 in diluent/water mass basis C = 2.5 mol 2MPZ∙kg solvent−1 T = 40 °C |
| [120] | TETA, DEEA | NMP | The solvent exhibits separation of two liquid phases. D = 46, 30, 25, 20 %wt. water content C = 1/3 TETA/DEEA in mol∙l−1 T = 40, 50, 60 °C |