Technical paper
Amine-based gas-sweetening processes prove economically more viable than the Benfield HiPure process
The removal of CO2 and H2S from natural gas streams is a crucial step for the Liquefied Natural Gas (LNG) industry. Since its inception, ADGAS (Abu Dhabi Gas Liquefaction limited) has been employing the Benfield HiPure process in its LNG plant in Das Island to purify sour natural gas to ultra-sweet specifications before it is compressed to produce LNG. This work compares the technical and economic performance of some simple amine-based processes to the Benfield HiPure process used in ADGAS LNG units. These process alternatives are evaluated and assessed based on the product purity, energy consumption and overall economic performance. Simulation results using the simulator ProMax clearly underpin the possibility of replacing the Benfield HiPure process with amine-based processes that achieve the same level of gas purity but with a better economics. Processes using mixed amines such as MDEA/DGA and MDEA/DEA prove more economically viable with a 50% reduction in capital costs and 20% and 48% savings on the stripping cost and the annual power needed for the solvent circulation respectively. Therefore, the prospect of shutting down the potassium carbonate section and retrofitting the DEA section to MDEA/DEA or MDEA/DGA appears very promising, allowing ADGAS to decrease operating costs and possibly increase capacity.
The removal of CO2 and H2S from natural gas streams is a crucial step for the Liquefied Natural Gas (LNG) industry. Since its inception, ADGAS (Abu Dhabi Gas Liquefaction limited) has been employing the Benfield HiPure process in its LNG plant in Das Island to purify sour natural gas to ultra-sweet specifications before it is compressed to produce LNG. This work compares the technical and economic performance of some simple amine-based processes to the Benfield HiPure process used in ADGAS LNG units. These process alternatives are evaluated and assessed based on the product purity, energy consumption and overall economic performance. Simulation results using the simulator ProMax clearly underpin the possibility of replacing the Benfield HiPure process with amine-based processes that achieve the same level of gas purity but with a better economics. Processes using mixed amines such as MDEA/DGA and MDEA/DEA prove more economically viable with a 50% reduction in capital costs and 20% and 48% savings on the stripping cost and the annual power needed for the solvent circulation respectively. Therefore, the prospect of shutting down the potassium carbonate section and retrofitting the DEA section to MDEA/DEA or MDEA/DGA appears very promising, allowing ADGAS to decrease operating costs and possibly increase capacity.