Technical paper
Simulation of the Benfield HiPure Process of Natural Gas Sweetening for LNG Production and Evaulation of Alternatives
Achieving specifications given by customers, including pipeline-operating companies, LNG storage facilities, and gas-processing plants requires the removal of CO2 and H2S from natural gas. It is also becoming more important to meet environmental regulations set by national and local governments. This paper summarizes a study which compares the Benfield HiPure-LNG Train of Abu Dhabi Gas Liquefaction Company Limited (ADGAS) sweetening plant to other sweetening processes using the modeling software ProMax®. Natural gas from the gas reservoirs, containing about 6-7 mole% acid gas, first comes into contact with hot potassium carbonate (30 wt% K2CO3) promoted with diethanolamine solution (3 wt% DEA), and finally with 20 wt% DEA solution. The simulation proved to predict the plant operating data accurately. Subsequently, additional alternatives to the Benfield HiPure process were investigated as potential options for replacement, including MDEA, MDEA/piperazine, and MDEA/DEA mixtures. The activated MDEA (50wt% MDEA + 3wt% PZ) with a two-stage flash is the best alternative, with a 36% decrease in the reboiler duty. This paper shows the possibility of shutting down the potassium carbonate section of the sweetening train and swapping the DEA solution in the immediate downstream unit for a mixed amine in order to reduce operating costs while continuing to meet the treated gas specifications. Preliminary results are presented here.
Achieving specifications given by customers, including pipeline-operating companies, LNG storage facilities, and gas-processing plants requires the removal of CO2 and H2S from natural gas. It is also becoming more important to meet environmental regulations set by national and local governments. This paper summarizes a study which compares the Benfield HiPure-LNG Train of Abu Dhabi Gas Liquefaction Company Limited (ADGAS) sweetening plant to other sweetening processes using the modeling software ProMax®. Natural gas from the gas reservoirs, containing about 6-7 mole% acid gas, first comes into contact with hot potassium carbonate (30 wt% K2CO3) promoted with diethanolamine solution (3 wt% DEA), and finally with 20 wt% DEA solution. The simulation proved to predict the plant operating data accurately. Subsequently, additional alternatives to the Benfield HiPure process were investigated as potential options for replacement, including MDEA, MDEA/piperazine, and MDEA/DEA mixtures. The activated MDEA (50wt% MDEA + 3wt% PZ) with a two-stage flash is the best alternative, with a 36% decrease in the reboiler duty. This paper shows the possibility of shutting down the potassium carbonate section of the sweetening train and swapping the DEA solution in the immediate downstream unit for a mixed amine in order to reduce operating costs while continuing to meet the treated gas specifications. Preliminary results are presented here.