Gas-to-Liquids (GTL) Plant Optimization Using Enhanced Synthesis Gas Reforming Technology

This paper evaluates method for optimisation of GTL plant using Steam/CO2 reforming for syngas generation. Extensive modelling of GTL plant has been done. Two cases were considered during the simulation of the GTL plant. The first case was the use of oxygen gas as the feed reactant gas using an auto-thermal reformer for the production of synthesis gas. The alternative case which is the proposed method uses CO2 in lieu of oxygen for the production of synthesis gas. CO2 method was chosen because of its cheap availability and the ability to be recycled from purge gas and reused reducing pollution. Honeywell’s Unisim software was used for the simulation and the Peng Robinson equation of state was chosen as the fluid property package. The simulation was done unit by unit and integration of all units was made. The synthesis gas unit was simulated in Unisim as a conversion type reactor using two separate reactors while three equilibrium reactors were used to control the water gas shift reaction to maintain favourable H2/CO ratio. The FT reactor was modelled as a multi-tubular bed reactor and simulated as a plug flow reactor (PFR) in Unisim using heterogeneous catalytic reaction type. Technical and economic performances were analyzed for both methods. The technical analyses revealed that the proposed steam/CO2 method gave a H2/CO ratio of 2.17 as against the 2.21 gotten for the ATR. Furthermore, the carbon efficiency of the two methods revealed 77.68% and 92.17% for base case and the proposed methods respectively showing that the proposed case has higher efficiency. The liquid yields show that the proposed method has a liquid yield of 5730b/d over the 5430b/d gotten from the base case representing an increase in product yield of 5.5%.