MODELLING AND SIMULATION OF METHANE BI-REFORMING FOR SYNGAS PRODUCTION - IN A MICRO-STRUCTURED REACTOR

Abstract

Methane reforming processes such as steam reforming, dry reforming, partial oxidation, and auto thermal reforming, produce syngas mixture of different H2/CO ratio. Bi-reforming of methane is considered in this study which is a combination of steam reforming and dry/carbondioxide reforming. It provides the flexibility to manipulate inlet CO2/CI-14 and F120/CH4 ratio for syngas production of desired 1-12/CO ratio. Nowadays, methanol is considered as future fuel (e.g. dirnethyl ether) and is raw material for numerous chemical products. A mixture of methanol and dirnethyl ether has high cetane number and is an exceptional diesel engine fuel. However, methanol production requires syngas composition of 2:1 and it can be easily produced from bi-reforming of methane. In the present study, a pseudo-homogenous one-dimensional single channel reactor model for bi-reforming over Ni-Ce02/MgAl204 catalyst has been developed and simulated using MATLAB R20I3b software. Kinetic parameters of bi-reforming reactions over Ni- - CeO2/MgAl2O4 catalyst are obtained from literature. Reactor model equations are solved using stiff ODE solver ODE 15S. The process variables (temperature, pressure and feed composition) - are optimized and the reactor performance is evaluated under obtained optimum condition. Four decision variables namely, temperature, pressure, H20/Cl-1 ratio and CO2/Cl-14 ratio are considered for optimization. Maximization of objective functions. i.e. C114 and CO2 conversion has been done to obtain optimum condition using genetic algorithm (GA). It is found that hi-reforming reactions are favored at high temperature. low pressure. The optimum temperature, pressure, CH4/l-120/CO2 ratio are found to be 1173 K. I bar and 1/0.8/0.4 respectively. Under optimum condition 99% Cl-L1 and 82% CO2 conversions are reached resulting in l-12/CO ratio of 2. Yield of H2 and CO is found to be 2.65 and 1.32 respectively. This process is an excellent approach to obtain syngas of desirable 112/CO ratio (-2) suitable for methanol and Fischer-Tropsch synthesis.