Thermodynamic Analysis of Increasing Hydrogen Yield of Syngas Produced from Biomass Gasification

摘要

Biomass gasification is an environmentally friendly means to produce hydrogen since it has zero net CO_2 emissions. Syngas produced is composed ofH_2, CO, CO_2, CH_4, trace of higher hydrocarbons (C_2H_6, C_2H_4, and C_2H_2), and tar. Hydrogen yield in the syngas produced from non-catalytic biomass gasification is relatively low. The hydrogen fraction, however, can be increased by converting CO, CH_4, higher hydrocarbons, and tar in a secondary reactor downstream. On the other hand, the compositionsof the syngas will determine the optimum yield of the process under certain conditions. This paper discusses thermodynamic limits of the synthesis gas upgrading process by employing minimization Gibbs free energy function method. The analysis is performed under temperature ranges of 400 to 1300 deg K, pressure of 1 to 10 aim (0.1 to 1 MPa), and different carbon to steam ratios. The results are compared to the experimental data found from literature.