1 Density modelling NH 3 -CO 2 -H 2 O liquid mixtures
2 Liquid density model in Aspen Plus Clarke model (for aqueous electrolyte molar volume) Molar volume for electrolyte solutions (V m l ), applicable to mixed solvents Based on apparent components V l m (298.15K) = x w V,l w + x am V,l am + 2x w x am K w,am V,l,l 0.5 w V am + 2xw x c K w,c V,l,l w V 0.5 c + 2x am x c K am,c V,l,l am V 0.5 c + x BC V BC + x CM V CM + x CB V CB V m l (T) = V m l (298.15K) V l s liquid molar volume for solvent mixtures based V l on liquid volume quadratic mixing rule s (T) V s l (298.15K) Non-electrolyte apparent components (molecular solvents): V e l liquid molar volume for electrolytes H 2 O (w) NH 3 (am) CO 2 (c) Electrolyte apparent components (ca): DIPPR equation for the computation of the pure component liquid molar volume: V W,l, V am,l and V c,l NH 4 HCO 3 (BC) NH 4 NH 2 COO (CM) (NH 4 ) 2 CO 3 (CB) x BC +x CM +x BC V ca = V ca + A ca, with x 1+ x BC +x CM +x w + x am + x c + x BC + x CM + x CB = 1 BC and where x i is computed from the true ionic concentrations 9 parameters to be estimated: K w,am, K w,c, K am,c, V BC, A BC, V CM, A CM, V CB, A CB
3 Default (Aspen Plus) liquid density model validation Default value of parameters: K w,am = 0 K w,c = 0; K am,c = 0 V BC = 0.0047 m3 A BC = 0.020 m3 V CM = 0.0012 m3 A CM = 0.020 m3 V CB = 0.0387 m3 A CB = 0.020 m3 If experimental data obtained at P vap > P atm and T < 0 C are not considered, the density is underestimated up to 20% Perkin (1889) -20% 3.9 T( C) 15.0 Perry s chemical engineers handbook 0 T( C) 25.0 Liu et al. (2012) 10.0 T( C) 50.0 Lichtfers (2000) 39.9 T( C) 80.1 This work (Lab samples) T C = 27.0 This work (Pilot plant samples) m NH3 0.6 m NH3 1.5 m NH3 1.9 m NH3 m NH3 11.9 T( C) 22.3 2.9 m NH3 mol NH3 = 26.5 25.2 24.3 12.2 = 17.7 CO 2 loading CO 2 loading CO 2 loading mol CO2 mol CO2 mol CO2 = 0 = 0 = 0 0 CO 2 loading mol CO2 mol NH3 0.82 CO 2 loading mol CO 2 mol NH3 = 0.5 10.6 0.28 CO 2 loading mol CO 2 mol NH3 0.71 Perkin. J Chem Soc 55 (1889) 680 Perry et al. Perry s chemical engineers handbook, 8th ed.; McGraw-Hill: New York, 2008 Liu et al. J Chem Eng Data 57 (2012) 2387-2393 Technology Lichtfers (2000) for a better society
4 Liquid density modelling NH 3 -H 2 O mixtures Regressed parameter: K w,am = 0.202 ± 0.003 K w,c = 0; K am,c = 0 Average absolute relative deviation: AARD % = 100 Absolute average deviation: AAD kg m 3 = 1 N N N i=1 N i=1 ρ exp,i ρ calc,i ρ exp,i ρ exp,i ρ calc,i Density regression of unloaded aqueous NH 3 solutions from the literature [1,2,3,4] using experimental data obtained at T 0 C and with P vap < P atm Perkin (1889) 3.9 T( C) 15.0 m NH3 = 26.5 CO 2 loading mol CO2 = 0 Perry s chemical engineers handbook 0 T( C) 25.0 0.6 m NH3 25.2 CO 2 loading mol CO2 = 0 Liu et al. (2012) 10.0 T( C) 50.0 1.5 m NH3 24.3 CO 2 loading mol CO2 = 0 Lichtfers (2000) 40.0 T( C) 60.1 1.9 m NH3 12.2 CO 2 loading mol CO2 = 0 AARD = 0. 4% max ARD = 1. 5% AAD = 3. 6 kg m3 max AD kg = 13. 5 m 3 [1] Perkin. J Chem Soc 55 (1889) 680 [2] Perry et al. Perry s chemical engineers handbook, 8th ed.; McGraw-Hill: New York, 2008 [3] Liu et al. J Chem Eng Data 57 (2012) 2387-2393 Technology [4] Lichtfers (2000) for a better society
5 Liquid density modelling CO 2 -NH 3 -H 2 O mixtures Fixed parameters: K w,am = 0.202 ± 0.003 K w,c = 0 K am,c = 0 Regressed parameters: V BC = 0.041 ± 0.003 m3 A BC = 0.030 ± 0.016 m3 V CM = 0.027 ± 0.007 m3 A CM = 0.09 ± 0.04 m3 V CB = 0.12 ± 0.05 m3 A CB = 0.2 ± 0.3 m3 Density regression of CO 2 -loaded aqueous NH 3 solutions from the literature [1] using experimental data obtained at T 0 C and with P vap < P atm Lichtfers (2000) 39.9 T( C) 80.1 1.9 m NH3 mol NH3 12.2 0.09 CO 2 loading mol CO2 0.82 AARD = 0. 1% max ARD = 0. 6% AAD = 1. 0 kg m3 max AD kg = 5. 8 m 3 But highly correlated parameters with high standard deviation in some cases Additional experiments might be required for modelling [1] Lichtfers (2000) 5
6 Liquid density model validation Regressed parameters: K w,am = 0.202 K w,c = 0; K am,c = 0 V BC = 0.041 m3 A BC = 0.030 m3 V CM = 0.027 m3 A CM = 0.09 m3 V CB = 0.12 m3 A CB = 0.2 m3 Model validation with independent liquid density measurements of the samples taken during the pilot plant tests of the CO 2 absorber This work (Lab samples) T C = 27.0 m NH3 mol NH3 This work (Pilot plant samples) 11.9 T( C) 22.3 2.9 m NH3 = 17.7 CO 2 loading mol CO 2 mol NH3 = 0.5 10.6 0.28 CO 2 loading mol CO2 0.71 The model consistently underpredicts the experimental liquid density values, but always below 2% AARD = 0. 6% max ARD = 1. 8% AAD = 6. 9 kg m3 max AD kg = 18. 5 m 3
7 Density model for CO 2 -NH 3 -H 2 O liquid mixtures Perkin (1889) Perry s chemical engineers handbook Liu et al. (2012) Lichtfers (2000) This work (Lab samples) -20% This work (Pilot plant samples) Default Aspen (Thomsen) AARD, % (max) 7.3 (21.1) ARD, kg/m 3 (max) 77.2 (243.6) This work (Thomsen) 0.5 (1.8) 5.5 (18.5) Average absolute relative deviation: AARD % = 100 N Absolute average deviation: AAD kg m 3 = 1 N N i=1 N i=1 ρ exp,i ρ calc,i ρ exp,i ρ exp,i ρ calc,i Perkin. J Chem Soc 55 (1889) 680 Perry et al. Perry s chemical engineers handbook, 8th ed.; McGraw-Hill: New York, 2008 Liu et al. J Chem Eng Data 57 (2012) 2387-2393 Lichtfers (2000)
8 CAP pilot testing CO 2 absorber tests
9 Test rig CO 2 absorber
10 Systematic treatment of raw data from pilot plant tests min F = y y σ y constrained to f x, y, u = 0 2 + u u σ u 2
11 Automatized steady state detection Experiment 14 Experiment 21 Sample 1 Sample 1 Sample 2 Sample 2
12 Mass balances before data reconciliation CO 2 capture test NH 3 removal test Composition and flowrate of liquid streams are critical for closing the mass balances
13 Reconciled data for analysis and modelling Inlet gas Failure in the in the inlet gas flowrate sensor during the tests CO 2 capture test NH 3 removal test
14 Reconciled data for analysis and modelling Outlet gas CO 2 capture test NH 3 removal test
15 Reconciled data for analysis and modelling Inlet liquid CO 2 capture test NH 3 removal test
16 Reconciled data for analysis and modelling Outlet liquid Most uncertainties are in the measurement of the flowrate and composition of the outlet liquid stream CO 2 capture test NH 3 removal test