Simulation Of Gas Sweetening Process CHEMCON- 2014 Simulation Of Gas Sweetening Process V.Bharath, T.Ajeeth Prabhu, S.Padma, Department of Chemical Engineering , Gayatri Vidya Parisad College of Engineering, Visakhapatnam, India M.Adity Kishore, Senior Engineer-Project Execution-Chemical, Brahmaputra Cracker and Polymer Limited (BCPL), Assam, India

Contents Introduction Why sweetening should be done???? Gas sweetening process Problem Statement Selection of Process Process description of Amine Absorption Process Parameters involved in Sweetening process Results and discussion Conclusion Simulation of Gas Sweetening Process- CHEMCON 2014

Introduction Natural gas is a fossil fuel formed when the layers of buried plants , animals are exposed to intense heat and pressure over thousand of years . Natural gas is a composition of Methane, Ethane, Propane, Butane, Nitrogen, CO2(Carbon Dioxide), H2S(Hydrogen Sulphide), some higher hydrocarbons and small amounts of Helium , water , impurities. Generally Natural gas is of two types: Acid Natural gas (containing significant amounts of H2S and Co2 ) Sweet Natural gas ( absence of H2S and Co2 ) Simulation of Gas Sweetening Process- CHEMCON 2014

Why sweetening should be done?????? The impurities present in the natural gas like H2S, CO2, Water , higher hydrocarbons and some other impurities leads to following problems:- Corrosion problems Transportation problem Reduction of calorific value Effects on the atmosphere In order to avoid all these problems the Acid Natural gas Should be treated. Simulation of Gas Sweetening Process- CHEMCON 2014

Problem Statement This paper presents a simulation study of the impact of various process parameters, on the separation and removal of acid gases from natural gas stream. The effect of the various parameters on the percentage removal of acid gas is studied. The parameters are optimized to give the maximum percentage removal. Simulation of Gas Sweetening Process- CHEMCON 2014

Gas Sweetening Process Gas sweetening process refers to a group processes that used to remove the CO2 and H2S. Gas sweetening process refers to an important purification process which is employed to remove the acidic contaminants from the natural gas prior to sale. This gas sweetening can be employed using the different methods to remove the H2S and CO2 present in the natural gas. PROCESS SOUR GAS ACID GASES Simulation of Gas Sweetening Process- CHEMCON 2014

Techniques Employed In Gas Sweetening Gas Sweetening Process Chemical Absorption Amine Other Chemicals Physical Methods Physical solvents Cryogenic Fractionation Membranes Adsorption Others Hybrid Direct Conversion Simulation of Gas Sweetening Process- CHEMCON 2014

Criteria for selection of process H2S and mercaptan concentration in the sour gas and sale gas C2O and total sulphur limits Maximum design flow rate Raw gas inlet pressure Requirement of sulphur recovery Acceptable methods of waste products disposal Simulation of Gas Sweetening Process- CHEMCON 2014

Amine treating The relative development of different Amines used in gas treating with the passage of time: Monoethanolamine (MEA) Diglycolamine (DGA) Diethanolamine (DEA) Methyldiethanolamine (MDEA) Simulation of Gas Sweetening Process- CHEMCON 2014

Amine absorption process (Chemical Absorption) Simulation of Gas Sweetening Process- CHEMCON 2014

Parameters involved in the process Temperature Pressure Composition of natural gas Lean amine concentration Flow rate of feed stream Number of trays in the absorber and stripper column Tray efficiency Type of amine used and Cost , etc Simulation of Gas Sweetening Process- CHEMCON 2014

HYSYS FLOWSHEET Simulation of Gas Sweetening Process- CHEMCON 2014

Result and discussions Pressure % removal of CO2 % removal of H2S 950Psi 98.2637 99.7846 1000Psi 98.2763 99.798 1250Psi 98.3081 99.8300 1500Psi 98.309 99.8326 Temperature % removal of CO2 % removal of H2S 80F 98.2763 99.79 86F 98.26304 99.78445 90F 97.93686 99.47807 95F 98.029 99.56331 Simulation of Gas Sweetening Process- CHEMCON 2014

Contd…… Flow rate % removal of CO2 % removal of H2S 15 MMSCFD 98.18766 98.18914 20 MMSCFD 98.56507 99.66456 25 MMSCFD 98.26304 99.78445 30 MMSCFD 98.99626 99.20887 Weight fraction % removal of CO2 % removal of H2S 22 98.965 99.69734 25 98.62902 99.82088 28 98.27634 99.79813 30 97.79345 99.87903 Simulation of Gas Sweetening Process- CHEMCON 2014

Conclusion The parameters are optimized using optimizer tool in ASPEN HYSYS to get maximum removal percentage of H2S and CO2and the optimized parameters are obtained as follows Parameters Optimized Values Temperature 86F Pressure 1000psi Molar Flow Rate 25MMSCFD Weight fraction 28% w/w % Removal of CO2 98.276345 % Removal of H2S 99.798128 Simulation of Gas Sweetening Process- CHEMCON 2014

References Dawodu O. F., Meisen A., 1996, Degradation of Alkanolamine Blends by Carbon Dioxide, The Canadian Journal of Chemical Engineering, Vol. 74, 960-966. Dr. A. H. Younger, P.Eng (April 2004), Natural Gas Processing and Technology, University of Calgary John Polasek, Jerry A. Bullin, A technical paper on Selecting Amines for Sweetening Units, Bryan Research & Engineering, Inc. Simulation of Gas Sweetening Process- CHEMCON 2014

Simulation of Gas Sweetening Process- CHEMCON 2014