Chemical Engineering & Technology, Vol.35, No.3, 420-430, 2012
Techno-Economic Analysis of a Gas-to-Liquid Process with Different Placements of a CO2 Removal Unit
Five placements of a CO2 removal unit in a gas-to-liquid (GTL) process are evaluated from an economical point of view. The kinetic model is the one given by Iglesia et al. for a cobalt-based Fischer-Tropsch (FT) reactor. For each alternative, the process is optimized with respect to steam-to-carbon ratio, purge ratio of light ends, amount of tail gas recycled to syngas and FT units, reactor volume, and CO2 recovery. The results indicate that carbon and energy efficiencies and the annual net cash flow of the process with or without CO2 removal unit are not significantly different, and that there is not much to gain by removing CO2 from the process. It is optimal to recycle about 97?% of the light ends to the process (mainly to the FT unit) to obtain higher conversion of CO and H2 in the reactor.