Improving GTL process by CO2 utilization in tri-reforming reactor and application of membranes in Fisher Tropsch reactor

•A new process is proposed for improving the GTL unit.•CO2 production reduces by application of membranes and optimizing the reactors.•Syngas production is optimized by application of tri-reforming reactor.•The GTL production is enhanced over two times of conventional process.•Associating an H-SOD membrane for water separation and a Pd/Ag membrane for syngas separation increase the selectivity and productivity of heavy hydrocarbons.

In this paper, tri-reforming of methane, Fisher Tropsch reaction, and membrane separation unit are used for improving the GTL process. The conventional process is composed of reforming and Fisher Tropsch reactions. For the improving syngas production the reforming reactor is substituted by a tri-reforming reactor, also, reaction pressure (1-10 bar) and temperature (500 °C-800 °C) are investigated. It is observed that decreasing the pressure and increasing the temperature improve the conversion of hydrocarbons and H2/CO ratio. It is illustrated that by controlling the oxygen injection rate to the tri-reforming reactor, CO2 production is minimized. In the case of Fisher Tropsch reactor, associating a Pd/Ag membrane for separation and recycling syngas to the reactor leads to yield of the light component such as methane reduces while the yield of heavy components increases. It is shown that application of tri-reforming reactor and membranes increase the gasoline and LPG production to 3337 bbL/day which is over two times of conventional process, while, the selectivity of carbon dioxide in Fisher Tropsch reactor is reduced 15% compared to conventional process.