生物质无氧气化制氢系统的热力学计算

THERMODYNAMIC CALCULATIONS OF BIOMASS ANAEROBIC GASIFICATION TECHNOLOGY FOR HYDROGEN PRODUCTION

介绍了一种基于CO_2接受体气化法的生物质无氧气化制氢系统。采用热力学平衡模型,研究了以玉米秸这一典型生物质为原料时系统压力、温度、[H_2O]/[C]比、[Ca]/[C]比对制氢过程的影响规律。获得典型工况下,系统制氢效率对这几个参数的相对线性敏感性系数。结果表明,H_2浓度在一定范围内随压力升高而明显增大,同时H_2产量会有少量降低,过高的温度会明显降低H_2产量及浓度。综合考虑,合适的气化压力在1.3～2.5MPa之间,不同压力具有不同适合制氢的最高温度。[H_2O]/[C]比的提高可以促进H_2生成,但大于1.5之后,H_2浓度明显下降,合适的[H_2O]/[C]比在1.5～2.0之间。[Ca]/[C]比的增加有利于H_2产量及浓度的提高。线性敏感性系数的计算表明,计算工况下[H_2O]/[C]比对制氢效率的影响非常大,压力和温度的影响也比较显著,[Ca]/[C]比的影响为零。

Based on CO2 acceptor gasification technology, a biomass anaerobic gasification technology for H2 production was presented. According to the system fueled with corn stalk, the influences of pressure, temperature, mole ratio of H2O and CaO to carbon in the biomass （[H2O]/[C] and [Ca]/[C]） on H2 production process was investigated by thermodynamic equilibrium calculations. At a typical case, the relative linear sensitivity coefficients of H2 production efficiency to these operating parameters were calculated. The results show that the H2 amount obviously increases, and H2 yield decreases slightly with increasing pressure in a specific range. Higher temperature obviously decreases the amount and mole fraction of H2. With a comprehensive consideration, the appropriate pressure should be selected at the range of 1.3MPa to 2.SMPa, and there are different maximum temperature which are suitable for H2 production under various pressure. The increasing ratio of [ H2O ] / [ C ] is helpful for the H2 production. But the H2 mole fraction is reduced if the ratio of [H2O]/[C] exceeds 1.5. The appropriate [H2O]/[C] should be selected from 1.5 to 2. The n2 amount and mole fraction increase with the increasing of [Ca]/[C]. The calculations of linear sensitivity coefficient show that [H2O]/[ C] has the greatest influence on H2 production efficiency, the influence of pressure and temperature are also obvious and [Ca]/[C] has no influence at the calculating case.