Investigation of natural gas sweetening process in corrugated packed bed column using computational fluid dynamics (CFD) model

Abstract In this work, a mathematical model based on computational fluid dynamics (CFD) is developed for absorption of acid gases, H 2 S and CO 2 , into amine solution in a structured packing with corrugated sheets. Localization of boundary conditions and hydrodynamic of the model are similar to the work of Shilkin. Two-dimensional mass and energy transfer equations with incorporation of chemical reactions between amines and acid gases are developed for moving liquid and gas in a cylindrical coordinate system for the channels produced from counter course assembling of the corrugated sheets. Solution to the governing equations based on mass and energy conservation concepts provides temperature and concentration profiles along the bed height and across the gas and reacting liquid film. Since methyl diethanol amine (MDEA) selectively absorbs H 2 S in the presence of CO 2 , to maintain the generality of the model, it is extended to investigate removal of CO 2 with a mixture of mono ethanol amine (MEA) or diethanol amine (DEA) and MDEA solutions. Structured packed column shows a better performance for absorption of acid gases in comparison with random packed column at equal height and diameter. In structured packed column, MEA shows to be more efficient for absorption of CO 2 in comparison with DEA.

[1]  James R. Fair,et al.  Mass transfer in gauze packings , 1985 .

[2]  Alessandro Paglianti,et al.  Liquid-Film Mass-Transfer Coefficient in a Column Equipped with Structured Packings , 1997 .

[3]  M. Rahimpour,et al.  Incorporation of Eulerian–Eulerian CFD framework in mathematical modeling of chemical absorption of acid gases into methyl diethanol amine on sieve trays , 2009 .

[4]  E. Y. Kenig,et al.  A new approach to fluid separation modelling in the columns equipped with structured packings , 2005 .

[5]  J. L. Paiva,et al.  Absorption of nitrogen oxides in aqueous solutions in a structured packing pilot column , 2004 .

[6]  R. Billet,et al.  Prediction of Mass Transfer Columns with Dumped and Arranged Packings , 1999 .

[7]  Geoffrey F. Hewitt,et al.  Thin film flow over structured packings at moderate Reynolds numbers , 2005 .

[8]  Lothar Spiegel,et al.  Distillation Columns with Structured Packings in the Next Decade , 2003 .

[9]  Eugeny Y. Kenig,et al.  Hydrodynamic-Analogy-Based Model for Efficiency of Structured Packing Columns , 2006 .

[10]  Z. Olujic.  Development of a complete simulation model for predicting the hydraulic and separation performance of distillation columns equipped with structured packings , 1997 .

[11]  A. Paglianti,et al.  Predicting the Efficiency of Corrugated Sheet Structured Packings with Large Specific Surface Area , 2004 .

[12]  A. Erasmus.  Mass transfer in structured packing , 2004 .

[13]  Mohammad Reza Rahimpour,et al.  MODELING AND SIMULATION OF INDUSTRIAL CARBON DIOXIDE ABSORBER USING AMINE-PROMOTED POTASH SOLUTION , 2004 .

[14]  Steven Pruess,et al.  A rate-based model for the design of gas absorbers for the removal of CO2 and H2S using aqueous solutions of MEA and DEA , 2001 .

[15]  Ludovic Raynal,et al.  Determination of mass transfer characteristics of co-current two-phase flow within structured packing , 2004 .

[16]  Ž. Olujić,et al.  Effect of Column Diameter on Pressure Drop of a Corrugated Sheet Structured Packing , 1999 .

[17]  Ross Taylor,et al.  Multicomponent mass transfer , 1993 .

[18]  Karl T. Chuang,et al.  Mass transfer in structured corrugated packing , 1991 .

[19]  Hiroshi Takeuchi,et al.  MASS TRANSFER COEFFICIENTS BETWEEN GAS AND LIQUID PHASES IN PACKED COLUMNS , 1968 .

[20]  Mohammad Reza Rahimpour,et al.  Enhanced carbon dioxide removal by promoted hot potassium carbonate in a split-flow absorber , 2004 .

[21]  Rajamani Krishna,et al.  Modeling of a reactive separation process using a nonequilibrium stage model , 1998 .

[22]  Gary T. Rochelle,et al.  Rate-based modeling of reactive absorption of CO2 and H2S into aqueous methyldiethanolamine , 1998 .

[23]  Ross Taylor,et al.  A second generation nonequilibrium model for computer simulation of multicomponent separation processes , 1994 .

[24]  S. Ayatollahi,et al.  Analysis of CO2 separation and simulation of a partially wetted hollow fiber membrane contactor. , 2008, Journal of hazardous materials.

[25]  James R. Fair,et al.  Distillation Columns Containing Structured Packings: A Comprehensive Model for Their Performance. 2. Mass-Transfer Model , 1996 .

[26]  James R. Fair,et al.  Distillation columns containing structured packings: a comprehensive model for their performance. 1. Hydraulic models , 1993 .

[27]  J. Fathikalajahi,et al.  Mathematical modeling of the simultaneous absorption of carbon dioxide and hydrogen sulfide in a hollow fiber membrane contactor , 2008 .