Synthesis gas production with high hydrogen concentration aspen simulation

Abstract

There is a growing need for hydrogen and future hydrogen economy becomes high on the scientific agenda, despite the “sustainable” routes are still too expensive; however, Steam reforming of hydrocarbons is the most feasible rout. This paper focuses on the production of Synthesis gas with high hydrogen concentration via process simulation using aspen plus simulator version 2006 and methane as a feedstock; the simulation process aimed mainly to produce synthesis gas rich in hydrogen with a minimum consumption of natural gas and agents of reforming and burning. An investigation of the effects of reactor (reformer) temperature, steam to natural gas (equivalence ratio) and the oxygen ratio in air on the composition of produced gases are conducted. The combustion reactor operated over a temperature range of 500-900 oC while varying equivalence ratio from 3:1 to 3:5. The results show that the hydrogen concentration in the produced gas increased rapidly with increasing reforming temperature and the best rang is (750-850 oC) where the highest conversion was at 850oC. Low equivalence ratio 3:1 is not preferred because it results low hydrogen concentration produced in synthesis gas but equivalence ratio equal to 3:3 is preferred for synthesis process as it results complete combustion of methane present in the feed resulting higher percentage of H2 in the produced gas. In additional, if the content of O2 in the air used in the combustion reactor as reforming agent was increased the content of hydrogen in the produced synthesis gas increased and on the other hand the content of nitrogen which is an inert gas is decreased by approximately (7.99%). However, 70 % O2 by volume content in the air stream ensures that the content of hydrogen (63.28%) in compared with pure oxygen gives 63.57%.