Alternative CO2 Removal Solutions for the LNG Process on an FPSO
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The Höegh LNG FPSO is designed for a CO2 removal of a gas stream containing 12.3% CO, but has a desire to add discuss alternative CO2 compositions.The thesis aims to give an introduction of some CO2 removal technologies. The work of this thesis is comprised of a literature study and evaluation of different aspects of these technologies. The evaluation includes discussing the aspects of the technologies and also collecting comparative data.There are three main technologies for CO2 removal; amine, membrane and molecular sieve. These were chosen from the literature study to be most suitable for removal of CO2 for LNG production. Two combinations are most relevant, the amine-membrane, and the amine-molecular sieve.Both the molecular sieve and the membrane have certain issues with regards to hydrocarbon losses. The best solution is to use both of these losses as fuel for the turbine. This however requires the turbine design to be adjusted accordingly.The molecular sieve is suggested used for CO2 compositions of less than 0.1%. The amine solution is suggested used for CO2 compositions between 0.1% and 6%. The membrane-amine solution is suggested for CO2 compositions above 6% because of the high bulk removal capability of the membrane and the ability for the amine process to remove CO2 on the lower part of the scale.