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Temperature Peak Analysis and Its Effect on Absorption Column for CO2 Capture Process at Different Operating Conditions

Harith Rashid, Nurul Hasan and M. Iskandar Mohamad Nor

Abstract

The role of temperature is important in CO2 capture processes. Unfortunately, detailed analysis on the temperature profile of the absorption column is scarce in the literature. Important factors like CO2 capture capacity and corrosion rate directly depend on temperature of the column. Many side reactions such as solvent degradation, formation of stable salts, corrosion and reduction in CO2 capture are prominent at a higher temperature. This study reports a broad study on the temperature profile for CO2 capture process based on a detailed mathematical model, Kent–Eisenberg vapor–liquid equilibrium (VLE) model. This model is quite accurate in calculating CO2 capture for any specific operating condition. Results produced from Kent–Eisenberg VLE model are consistent with experimental data. This study reports temperature profiles of an absorption column for different operating conditions. Moreover, it was found that CO2 absorption is more effective at low and ambient temperatures than at high temperature confirmed by a peak temperature in all cases and in the lower section of the column, which is attributed to exothermic CO2 absorption in monoethanolamine. This temperature variation of the column will be helpful in designing CO2 capture plants.

Nomenclature

ae

effective mass-transfer area (m2/m3)

au

interfacial mass-transfer area (m2/m3)

Ci

molar concentration (mol/m3)

cp

specific heat capacity (J/mol K)

Di

diffusivity of component i (m2/s)

E

activation energy (J/mol)

ε

hold-up (m3/m3)

ΔRH

reaction heat (J/mol)

ΔVH

vaporization/condensation heat (J/kmol)

F

volumetric flow rate (m3/s)

h

heat-transfer coefficient (J/m3 K s)

Kjk0

pre-exponential function (m3/mol s)

k

heat-transfer coefficient (J/m2 K s)

M

molecular weight (g/mol)

N

interfacial molar flux (mol/m2 s)

Re

Reynolds number

Rj

reaction rate of reaction j (mol/m3 s)

s

column’s cross-sectional area (m2)

S

source of heat in the system (J/m3 s)

T

temperature (K)

t

time (s)

u

velocity in x direction (m/s)

v

velocity in y direction (m/s)

w

velocity in z direction (m/s)

z

axial column coordinates

ρ

density (kg/m3)

Subscript/superscript

Vector

G

gas phase

L

liquid phase

i

CO2, MEA and H2O

j

no. of stages in absorption column

c

heat transfer by convection

v

heat transfer by vaporization

r

heat of reaction

Appendix

Mass-transfer area

Eq. (8) represents the correlation for calculating the mass-transfer area in the column [32].

(8)aeau=0.456ReL0.3

where ae (m2/m3) and au (m2/m3) are effective mass-transfer area and interfacial area of the packing used, respectively. Re is the Reynolds number of liquid. This expression is used to calculate the interfacial area.

Heat balance equation in the liquid phase is given as

(9)ρLcp,LTLt=xkLTLxρLcp,Lux,LTL+ykLTLyρLcp,Lvy,LTL+zkLTLzρLcp,Lwz,LTL+S

This is a three-dimensional energy-transfer equation, which is used for heat balance of different processes. ρL is the density of liquid, cp,L is the specific heat of the liquid phase, ux,L is the velocity in x direction, vy,L is the velocity of liquid in y direction, wz,L is the velocity of liquid in z direction, and TL is temperature of the liquid phase. Unit for the left-hand side of the above equation is calculated out to be W/m3. Therefore, to make the units consistent, all the terms in eq. (9) should have the same units including the source term S. The source term includes Sc,L, for heat transfer through convection in the liquid phase, Sr,L, for heat of reaction and Sv,L, for heat of vaporization or condensation. Therefore, the modified form of eq. (9) becomes

(10)ρLcp,LTLt=xkLTLxρLcp,Lux,LTL+ykLTLyρLcp,Lvy,LTL+zkLTLzρLcp,Lwz,LTL+Sc,L+Sr,L+Sv,L

It is important to note that the unit of all the terms in eq. (10) should be equal to W/m3. For one-dimensional analysis, eq. (10) can be reduced to the following form:

(11)ρLcp,LTLt=zkLTLzρLcp,Luz,LTL+Sc,L+Sr,L+Sv,L

According to law, heat transfer by convection is given as:

(12)Sc,L=hauTGTL

where h (W/m2 K) is heat-transfer coefficient, au (m2/m3) is interfacial area, and TG and TL represent temperature for liquid and gas phase, respectively. However, heat of reaction for CO2 absorption in aqueous amine solution is generalized with the standard expression for exothermic heat of reaction as:

(13)Sr,L=NRΔRH

where minus sign in eq. (13) represents exothermic reaction between CO2 and MEA. NR (mol/m3 s) is the number of reactants, reacting per second and ΔRH is heat of reaction in J/mol.

Similarly, expression for heat of vaporization or condensation for all the components is given as follows:

(14)Sv,L=auNΔvH

where au (m2/m3) represents interfacial area between liquid and gas as vaporization and condensation takes place on the interface, N (mol/m2 s) is molar flux, and Δv,iH (J/mol) represents heat of vaporization or condensation. However, there are three components such as CO2, MEA and H2O. So, eq. (14) is modified as a sum of all the components as:

(15)Sv,L=auNiΔv,iH

Heat of vaporization for all the components is summarized in eq. (15). Now, eq. (11) can be modified by adding all the terms for heat transfer and also neglecting KL for the liquid phase as its value is very less in this case. Therefore, heat balance for the liquid phase can be modified dividing both sides with ρLcp,L to separate the temperature, and the new form of the equation is given as:

(16)TLt=uz,LTLz+hauρLcp,L(TGTL)(NRΔRHρLcp,L)au.(NiΔv,iHρLcp,L)

Eq. (16) is the expression for heat balance in the liquid phase.

Heat balance in gas phase

Heat balance in gas phase is obtained by changing eq. (10) as:

(17)ρGcp,GTGt=xkGTGxρGcp,Gux,GTG+ykGTGyρGcp,Gvy,GTG+zkGTGzρGcp,Gwz,GTG+Sc,G+Sr,G+Sv,G

For the gas phase, there is no vaporization, so Sv,L = 0, and it is also assumed that there is no reaction taking place in the gas phase, Sr,L = 0. Similarly, KG for gas phase is very low, so it is also neglected in heat balance expression for gas phase. Eq. (17) is modified by these assumptions as:

(18)ρGcp,GTGt=ρGcp,Guz,GTGz+Sc,G

Now, heat transfer by convection in gas phase is given as:

(19)Sc,G=hauTLTG

Eq. (18) is modified by adding the term for convective heat transfer from eq. (19) and dividing both sides of the equation with ρLcp,L to get the equation with temperature term as:

(20)TGt=uz,GTGz+hauρGcp,GTLTG

Eq. (20) is heat balance equation for gas phase in CO2 absorption process.

Stage efficiency of absorber

For a vapor–liquid separation process, considering that both liquid and gas streams are interacting at the interface [32]. Murphree’s plate efficiency for component i on stage j of the column is given as:

(21)ηM=yi,jyi,j+1yi,jyi,j+1

Eq. (21) represents Murphree’s plate efficiency for equilibrium stage. However, for non-equilibrium stage, gas flow rate FG is introduced into the correlation for Murphree’s plate efficiency. So, eq. (21) is modified in a new form as follows:

(22)ηj=FG,jyi,jFG,j+1yi,j+1FG.jyi,jFG,j+1yi,j+1

where yi,j in eq. (22) represents the composition of molecular concentration of different components leaving the stage j at equilibrium.

Liquid loading packing factor for gas and liquid

Liquid loading gas factors for liquid and gas streams represented as Gfz and Lfz (kg/m2 s) are calculated by using eqs (23) and (24), respectively, as follows:

(23)Gfz=986GρzG0.53600Fpd200.5100.3ρzG
(24)Lfz=L6.24ρ20Fpd0.5μzL10000.1

where G′ and L′ are gas and liquid mass velocity (kg/m2 s), respectively, ρG and ρG (kg/m3) are mass density for gas and liquid streams, respectively, and µL is viscosity of liquid (kg/m s) [32].

Pressure drop on each stage

The total pressure drop for each stage along the column is calculated using eq. (25) [32]:

(25)ΔP=zΔPzdz

References

1. ChapelDG, MarizCL, ErnestJ. Recovery of CO2 from flue gases: commercial trends. In: Originally presented at the Canadian Society of Chemical Engineers annual meeting, 1999:117.Search in Google Scholar

2. HerzogH. An introduction to CO2 separation and capture technologies. MIT Energy Laboratory, 1999.Search in Google Scholar

3. AlivisatosP, BuchananM. Report of the basic energy sciences workshop for carbon capture: beyond 2020. Lawrence Berkeley National Laboratory & Oak Ridge National Laboratory, 2010.Search in Google Scholar

4. SchäfferA, BrechtelK, ScheffknechtG. Comparative study on differently concentrated aqueous solutions of MEA and TETA for CO2 capture from flue gases. Fuel2012;101:14853.10.1016/j.fuel.2011.06.037Search in Google Scholar

5. CifernoJ, LitynskiJ, PlasynskiS. DOE/NETL carbon dioxide capture and storage RD&d roadmap. Strategic Center for Coal, National Energy Technology Laboratory, 2010.Search in Google Scholar

6. Material Safety Data Sheet. The Dow Chemical Company, MSDS No: 1592: p. 1 of 17, 2003.Search in Google Scholar

7. KladkaewN, IdemR, TontiwachwuthikulP, SaiwanC. Corrosion behavior of carbon steel in the monoethanolamine–H2O–CO2-O2-SO2 system: products, reaction pathways, and kinetics. Ind Eng Chem Res2009;48:1016979.10.1021/ie900746gSearch in Google Scholar

8. SoosaiprakasamIR, VeawabA. Corrosion inhibition performance of copper carbonate in MEA-CO2 capture unit. Energy Procedia2009;1:2259.10.1016/j.egypro.2009.01.032Search in Google Scholar

9. KladkaewN, et al. Studies on corrosion and corrosion inhibitors for amine based solvents for CO2 absorption from power plant flue gases containing CO2, O2 and SO2. Energy Procedia2011;4:17618.10.1016/j.egypro.2011.02.051Search in Google Scholar

10. LeeIn-Y, LeeJH, KimJ-H. Effect of corrosion inhibitor on oxidation of MEA in carbon dioxide capture. J Chem Eng Jpn2011;44:2737.10.1252/jcej.10we289Search in Google Scholar

11. NguyenaT, HilliardM, RochelleG. Volatility of aqueous amines in CO2 capture. Energy Procedia2011;4:162430.10.1016/j.egypro.2011.02.033Search in Google Scholar

12. ThitakamolB, VeawabA. Foaming model for CO2 absorption process using aqueous monoethanolamine solutions. Colloids Surf A Physicochem Eng Aspects2009;349:12536.10.1016/j.colsurfa.2009.08.006Search in Google Scholar

13. ClosmannF, RochelleGT. Degradation of aqueous methyldiethanolamine by temperature and oxygen cycling. Energy Procedia2011;4:238.10.1016/j.egypro.2011.01.018Search in Google Scholar

14. RaynalL, BouillonP-A, GomezA, BroutinP. From MEA to demixing solvents and future steps, a roadmap for lowering the cost of post-combustion carbon capture. Chem Eng2011;171:74252.10.1016/j.cej.2011.01.008Search in Google Scholar

15. IdemRO, LawalAO. Kinetics of the oxidative degradation of CO2 loaded and concentrated aqueous MEA–MDEA blends during CO2 absorption from flue gas streams. Ind Eng Chem Res2006;45:26017.10.1021/ie050560cSearch in Google Scholar

16. ZoannouK-S, SapsfordDJ, GriffithsAJ. Thermal degradation of monoethanolamine and its effect on CO2 capture capacity. Int J Greenhouse Gas Control2013;17:42330.10.1016/j.ijggc.2013.05.026Search in Google Scholar

17. VevelstadSJ, et al. Oxidative degradation of 2-ethanolamine: the effect of oxygen concentration and temperature on product formation. Int J Greenhouse Gas Control2013;18:88100.10.1016/j.ijggc.2013.06.008Search in Google Scholar

18. ZoghiAT, FeyziF, ZarrinpashnehS. Experimental investigation on the effect of addition of amine activators to aqueous solutions of N-methyldiethanolamine on the rate of carbon dioxide absorption. Int J Greenhouse Gas Control2012;7:1219.10.1016/j.ijggc.2011.12.001Search in Google Scholar

19. GibbinsJ, ChalmersH. Carbon capture and storage. Energy Policy2008;36:431722.10.1016/j.enpol.2008.09.058Search in Google Scholar

20. TobiesenA, Schumann-OlsenH. Obtaining optimum operation of CO2 absorption plants. Energy Procedia2011;4:174552.10.1016/j.egypro.2011.02.049Search in Google Scholar

21. LiH, DitarantoM, YanJ. Carbon capture with low energy penalty: supplementary fired natural gas combined cycles. Appl Energy2012;97:1649.10.1016/j.apenergy.2011.12.034Search in Google Scholar

22. ZhuD, FangM, LvZ, WangZ, LuoZ. Selection of blended solvents for CO2 absorption from coal-fired flue gas. Part 1: monoethanolamine (MEA)-based solvents. Energy Fuels2012;26:14753.10.1021/ef2011113Search in Google Scholar

23. PuxtyG, RowlandR, AttallaM. Comparison of the rate of CO2 absorption into aqueous ammonia and monoethanolamine. Chem Eng Sci2010;65:91522.10.1016/j.ces.2009.09.042Search in Google Scholar

24. ZhaoY, ZhangX, ZengS, ZhouQ, DongH, TianX, et al. Density, viscosity, and performances of carbon dioxide capture in 16 absorbents of amine+ionic liquid+H2O, ionic liquid + H2O, and amine + H2O systems. J Chem Eng Data2010;55:351319.10.1021/je100078wSearch in Google Scholar

25. MandalaBP, GuhaM, BiswasbAK, BandyopadhyayaSS. Removal of carbon dioxide by absorption in mixed amines: modelling of absorption in aqueous MDEA/MEA and AMP/MEA solutions. Chem Eng Sci2001;56:621724.10.1016/S0009-2509(01)00279-2Search in Google Scholar

26. EdaliM, AboudheirA, IdemR. Kinetics of carbon dioxide absorption into mixed aqueous solutions of MDEA and MEA using a laminar jet apparatus and a numerically solved 2D absorption rate/kinetics model. Int J Greenhouse Gas Control2009;3:55060.10.1016/j.ijggc.2009.04.006Search in Google Scholar

27. KvamsdalHM, RochelleGT. Effects of the temperature bulge in CO2 absorption from flue gas by aqueous monoethanolamine. Ind Eng Chem Res2008;47:86775.10.1021/ie061651sSearch in Google Scholar

28. CormosA-M, GasparJ. Assessment of mass transfer and hydraulic aspects of CO2 absorption in packed columns. Int J Greenhouse Gas Control2012;6:2019.10.1016/j.ijggc.2011.11.013Search in Google Scholar

29. BiliyokC, LawalA, WangM, SeibertF. Dynamic modelling, validation and analysis of post-combustion chemical absorption CO2 capture plant. Int J Greenhouse Gas Control2012;9:42845.10.1016/j.ijggc.2012.05.001Search in Google Scholar

30. KhanFM, KrishnamoorthiV, MahmudT. Modelling reactive absorption of CO2 in packed columns for post-combustion carbon capture applications. Chem Eng Res Des2011;89:16008.10.1016/j.cherd.2010.09.020Search in Google Scholar

31. GasparJ, CormosA-M. Dynamic modeling and absorption capacity assessment of CO2 capture process. Int J Greenhouse Gas Control2012;8:4555.10.1016/j.ijggc.2012.01.016Search in Google Scholar

32. MoresP, ScennaN, MussatiS. CO2 capture using monoethanolamine (MEA) aqueous solution: modeling and optimization of the solvent regeneration and CO2 desorption process. Energy Procedia2012;45:104258.10.1016/j.energy.2012.06.038Search in Google Scholar

33. AronuUE, SvendsenHF, HoffKA, JuliussenO. Solvent selection for carbon dioxide absorption. Energy Procedia2009;1:10517.10.1016/j.egypro.2009.01.139Search in Google Scholar

34. TanLS, et al. Removal of high concentration CO2 from natural gas at elevated pressure via absorption process in packed column. J Nat Gas Chem2012;21:710.10.1016/S1003-9953(11)60325-3Search in Google Scholar

35. AroonwilasA, VeawabA. Characterization and comparison of the CO2 absorption performance into single and blended alkanolamines in a packed column. Ind Eng Chem Res2004;43:222837.10.1021/ie0306067Search in Google Scholar

36. AboudheirA, TontiwachwuthikulP, ChakmaA, IdemR. On the numerical modeling of gas absorption into reactive liquids in a laminar jet absorber. Can J Chem Eng2003;81:60412.10.1002/cjce.5450810336Search in Google Scholar

37. deMontignyD, AboudheirA, TontiwachwuthikulP. Modelling the performance of a CO2 absorber containing structured packing. Ind Eng Chem Res2006;45:2594600.10.1021/ie050567uSearch in Google Scholar

38. van NieropEA, HormozS, HouseKZ, AzizMJ. Effect of absorption enthalpy on temperature-swing CO2 separation process performance. Energy Procedia2011;4:178390.10.1016/j.egypro.2011.02.054Search in Google Scholar

39. KentR, EisenbergB. Better data for amine treating. Hydrocarbon Process1976;55:8790.Search in Google Scholar

40. Haji-SulaimanMZ, ArouaMK, BenamorA. Analysis of equilibrium data of CO2 in aqueous solutions of diethanolamine (DEA), methyldiethanolamine (MDEA) and their mixtures using the modified kent eisenberg model. Trans IChemE1998;76.10.1205/026387698525603Search in Google Scholar

41. RozaM, HunkelerR, BervenOJ, IdeS. Sulzer mellapak in refineries and in the petrochemical industry. Proc Int Conf Petroleum Refining Petrochemical Process1991;2:9439.Search in Google Scholar

42. Rameshwar HiwaleSH, SmithR. Model building methodology for multiphase reaction systems modeling of CO2 absorption in monoethanolamine for laminar jet absorbers and packing beds. Ind Eng Chem Res2012;51:432846.10.1021/ie201869wSearch in Google Scholar

43. ZhangY, QueH, ChenC-C. Thermodynamic modeling for CO2 absorption in aqueous MEA solution with electrolyte NRTL model. Fluid Phase Equilibria2011;311:6775.10.1016/j.fluid.2011.08.025Search in Google Scholar

44. BoributhS, RongwongW, AssabumrungratS, LaosiripojanaN, JiraratananonR. Mathematical modeling and cascade design of hollow fiber membrane contactor for CO2 absorption by monoethanolamine. J Membr Sci2012;401–402:17589.10.1016/j.memsci.2012.01.048Search in Google Scholar

45. GaoX, LiX, ZhangR, LiH. Pressure drop models of seepage catalytic packing internal for catalytic distillation column. Ind Eng Chem Res2012;51:744752.10.1021/ie201686ySearch in Google Scholar

46. ChemtechS. Structured packings for distillation, absorption and reactive distillation. Switzerland.Search in Google Scholar

47. OndaK, TakeuchoH, OkumotoY. Mass transfer coefficients between gas and liquid phases in packed columns. J Chem Eng Jpn1968;56.10.1252/jcej.1.56Search in Google Scholar

48. Henriques de BritoM, von StockarU, Menendez BangerterA, BomioP, LasoM. Effective mass-transfer area in a pilot plant column equipped with structured packings and with ceramic rings. Ind Eng Chem Res1994;33:64756.10.1021/ie00027a023Search in Google Scholar

49. TobiesenFA, HillestadM, KvamsdalH, ChikukwaA. A general column model in CO2SIM for transient modeling of CO2 absorption processes. In: Trondheim CCS Conference (TCCS-6) Trondheim, Norway, 2011.10.1016/j.egypro.2012.06.071Search in Google Scholar

50. SimonLL, EliasY, PuxtyG, ArtantoY, HungerbuhlerK. Rate based modeling and validation of a carbon-dioxide pilot plant absorption column operating on monoethanolamine. Chem Eng Res Des2011;89:168492.10.1016/j.cherd.2010.10.024Search in Google Scholar

51. KuntzJ, AroonwilasA. Mass-transfer efficiency of a spray column for CO2 capture by MEA. Energy Procedia2009;1:2059.10.1016/j.egypro.2009.01.029Search in Google Scholar

Published Online: 2014-4-29
Published in Print: 2014-12-1

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