PROPERTIES MEA/AQUEOUS SOLUTIONS MOLECULAR SIMULATION

Transcription

1 Renewable energes Eco-frendly producton Innovatve transport Eco-effcent processes Sustanable resources PREDICTION OF PHYSICAL PROPERTIES OF CO IN IONIC MEA/AQUEOUS SOLUTIONS BY MOLECULAR SIMULATION C. Neto-Dragh, a G. Orozco, a,b A. D. Macke, b R. Lugo, a N. Ferrando, a V. Lachet a a Department of thermodynamcs and Molecular Smulaton Thermodynamcs 0, -3 September 0, Athens b ETSEQ, Departament d Engnyera Qumca, Unverstat Rovra Vrgl

2 Absorpton column desgn Z K L : lqud mass transfer coeffcent K G : gas mass transfer coeffcent H : Henry constant E : Enhancement factor from chemcal reacton D CO : CO dffuson coeffcent n soluton DMEA : MEA dffuson coeffcent n soluton [CO ] : CO equlbrum molar concentraton [MEA] : MEA equlbrum molar concentraton k mn : Reacton rate constant of m order for [CO] and n order for [MEA] M = z = G S P ( / K + / K H ) β = E E L y y β = 4 A ( y y )( y ) 0 M G DCO km n ( m + ) A + dy A ( E ) ( E ) ( ) m [ CO ] [ MEA] K L n ME A + E = + M E [ MEA] L D [ CO ] D G CO MEA Problem : We need H and D Expermental determnaton of H and D MEA D CO s extremely dffcult InMoTher, Lyon 9 0 Mars 0

3 Objectves To have access of thermo-physcal propertes of CO n MEA/H O and MEA/MEA-H + /MEA-COO - /H O systems requred n absorber desgn usng Molecular Smulaton technques. Estmaton of the physcal solublty of CO Estmaton of CO dffuson coeffcent n aqueous MEA and MEA onc soluton 3 InMoTher, Lyon 9 0 Mars 0

4 Intermolecular Potentals MEA/MEA-H + /MEA-COO - : New Hybrd-OPLS Jorgensen et al JACS 8, p5-36 (996) / AMBER wth a new set of charges for lqud condtons (Dev of. % for ρ and 7. % for η) CO : EPM, Harrs et al J. Phys. Chem. 99, 0-04 (995) H O : SPC/E, Berendsen et al J. Phys. Chem 9, 669 (987). 4 InMoTher, Lyon 9 0 Mars 0

5 Estmaton of H: Monte Carlo Thermodynamc Integraton: Gradual nserton of the solute the solvent (n k steps): G = 0 U ( λ) λ λ dλ Wdom test nserton: drect transton λ = 0 to λ = H = f x λ = 0 λ = λ λ = the solute doesn't nteract wth the solvent the solute nteracts wth the solvent wth a scalng factor λ Solute-solvent dsperson/repulson nteracton: LJ "soft-core" potental U LJ 4 j j LJ the solute fully nteracts wth the solvent = 4ε λ 6 6 r j r j α vdw ( λlj ) α vdw ( λlj ) + + σ j σ j Solute-solvent electrostatc nteracton: Coulombc potental U el j λ q q = 4πε C j 0 5 InMoTher, Lyon 9 0 Mars 0

6 Henry Constant 0000 Pure water 0000 MEA (30%w)+ Water H (MPa) CO - Wdom CO - L (995) HS - Wdom HS - correlaton CH4 - Wdom CH4 - correl Dhma NO - Wdom NO - L (995) T (K) H (MPa) CO Wdom CO Int. Therm. CO -est (NO analogy) NO Wdom NO -exp L (995) NO -exp Tsa (000) NO -exp Sandall (00) NO -exp Weland (996) CH4 Wdom CH4 -exp (40 wt%) HS Wdom T (K) Same order of magntude between Exp-Sm The N O analogy n water H CO /H N0 (.4 sm vs 0.75 exp). In H CO n MEA+H O H CO ~ H N0 Coherent results between Wdom - TI 6 InMoTher, Lyon 9 0 Mars 0

7 HCO Henry Constant n onc soluton 3 CO + R NH + ( CO ) + H O + HCO + HO R NH CO + HO + ( CO ) + H O R NH + NH ( CO ) + CO3 + NH 3 3 Equlbrum concentratons estmated by a G mn model (IFPE) H CO n the onc soluton s 78.5 MPa close to 0 MPa n MEA+HO (303.5 K, bar). Concentraton of molecular CO s smlar usng dfferent approaches! MEA + H0 MEA + H0 MEA on + H0 MEA on + H0 [CO] (KH Wdom) [CO] (Gbbs) [CO] (KH Wdom) [CO] (Gbbs) 4.53E E E E-04 7 InMoTher, Lyon 9 0 Mars 0

8 Transport of CO n lqud solutons 8 Fck's dffuson J coeffcent = cd x Computaton of Maxwell-Stefan through MD Λ j matrx obtaned from the poston of each spece (R) n the system N N j = lm ( R ( t + t) R ( t + t) ) R ( t + t) R ( t + t) Λ ( ) j l, l, k, j k, j 6 t N t l= k = InMoTher, Lyon 9 0 Mars 0 smulatons D = DQ Onsager's recprocty Λ Λ Λ Λ D = x x M Λj = 0 x x x x. Taylor and Krshna, Multcomponent mass transfer; Wley 993 Garca Ratés et al. JPCB 6, 787 (0) D j Transport dffuson of CO n MEA/H O: We use an approxmaton specally developed for dluted gases n onc solutons D obtaned wth fnte-sze scalng L The thermodynamc factor Q s obtaned through thermodynamc data (NRTL model) Q = lnϕ x + x H O, T, P

9 Valdaton of optmsed potental of MEA n aqueous soluton Exp OPLS opt 00 Exp OPLS opt ρ ( (kg/cm 3 ) a) η ( (cp) 0 b) 950 0,0 0, 0,4 0,6 0,8,0 w MEA Varaton of densty (a) and vscosty (b) of soluton n functon of the mass fracton of MEA at 303 K and bar. Even wth the new optmsed potental of MEA we obtan a 4 % of devaton of the soluton vscosty at 30%w of MEA! Problem between MEA/H O nteractons 0, 0,0 0, 0,4 0,6 0,8,0 w MEA 9 InMoTher, Lyon 9 0 Mars 0

10 D MEA n water D [m /s ] 4.0E E E-09.5E-09.0E-09.5E-09.0E E-0 0.0E+00 Correcton wth Stokes-Ensten Wlke et Chang D (Darken MD) D (MS MD) kbt D = CTηR ηsm D c = D η exp IFPEN D (Darken MD corr) D (MS MD corr) sm ω (MEA) Λ Λ x x x xλ + Λ x D MEA n water at 303 bar. Smulaton results at 30%w of MEA are corrected wth exp. vscosty usng S-E! D MS Maxwell-Stefan () = = x Λ x xλ x Λ x D MS = Λ D = x D + x MS MEAH Darken () D O H O MEA MEA H Coeffcent Q (NRTL) Q MEA = lnϕ 0 MEA + xmea x MEA H O, T, P MS D = Q MEA D MEA H O 0 InMoTher, Lyon 9 0 Mars 0

11 D CO n MEA/H O (no chemcal reacton) D [m /s ] 3.00E-09.50E-09.00E-09.50E-09 Correcton wth Stokes-Ensten η sm D c = Dsm η exp D = x D + x MS MEAH Darken () D O H O MEA MEA H Correlaton (L) CO NO ( D MEA H / ) 6,4% O DMEAH O Corr CO NO ( D MEA / D ) % H O MEAH O SM 0.00E E E+00 Mandal 005 L 995 IFPEN Wlke et Chang mod D (Darken SM corr) T [ C] Wlke et Chang D (Darken SM) Corr. SM Varaton of D CO n MEA/H O wth bar. Smulaton results at 30%w of MEA. Correlaton D kbt = C ηr T ( 0, ) C T = 94, exp 7 T R =,90x0 0 m InMoTher, Lyon 9 0 Mars 0

12 Prelmnary results : D CO n MEA/MEA-H + /MEA-COO - /H O 5500 molecules, ns 64 proc, 5 days InMoTher, Lyon 9 0 Mars 0

13 D CO n MEA / MEA-H + / MEA-COO - / H O D [m /s].50e-09.30e-09.0e-09.90e-09.70e-09.50e-09.30e-09.0e E E-0 Mandal 005 L 995 IFPEN Wlke et Chang Wlke et Chang modfé D (Darken MD) MS MEAH Darken () D = x D + x D O H O MEA MEA H No Stokes-Ensten correcton (@ 40 C η exp = η sm =.7 cp ) E InMoTher, Lyon 9 0 Mars 0 T [ C] Temperature varaton of D CO nsde onc system ([conc.] of onc speces estmated wth 30%w of MEA and n CO /n MEA =0.5). Amudsen et al.

14 D CO n MEA / MEA-H + / MEA-COO - / H O.E-08 IFPEN (30%) D (Darken MD 30%) D [ m / s ].E-09.E-0 IFPEN (60%) D (Darken MD 60%).E T [ C] Temperature varaton of D CO nsde onc system (ntal condtons of 30%w and 60%w of MEA and n CO /n MEA =0.5). 4 InMoTher, Écrre c dans Lyon le 9 masque 0 Mars le nom 0 de votre Drecton Écrre c dans le masque le ttre de la présentaton Date de la présentaton

15 Conclusons New AA potental for MEA (. % for ρ and 7. % for η) Henry constant of CO n MEA/H O s n qualtatve agreement wth est. usng N O analogy Wdom an TI methods gve coherent results (Convergence N MC steps > 00 x0 6 ) Estmaton of CO dffuson coeffcent n aqueous MEA and onc MEA solutons Problem of cross MEA/water nteractons (η η,, D ) CO n qualtatve agreement wth correlatons n MEA/H O (after S-E correcton) D CO D CO CO n agreement wth correlatons n onc system CO 5 InMoTher, Écrre c dans Lyon le 9 masque 0 Mars le nom 0 de votre Drecton Écrre c dans le masque le ttre de la présentaton Date de la présentaton

16 Acknowledgements ANR MEMOBIOL for TI mplementatons GENCI project x for CPU tme LCP/CNRS & B. Rousseau for Newton s MD code MC smulatons wth Gbbs code (LCP+IFPEN) 6 InMoTher, Écrre c dans Lyon le 9 masque 0 Mars le nom 0 de votre Drecton Écrre c dans le masque le ttre de la présentaton Date de la présentaton