加压下氢气对煤焦水蒸气气化反应的影响

在加压固定床微分反应器上对霍林河褐煤焦(HLH)、神木烟煤焦(SM)和晋城无烟煤焦(JC)与水蒸气/氢气混合气的加压气化反应特性进行了研究。结果表明,氢气对煤焦水蒸气气化反应具有明显的抑制作用,其抑制作用大小分别随氢气分压、总压和煤阶的提高而增强,而随反应温度升高而减弱;有氢气存在和无氢气存在时煤焦水蒸气气化反应过程都能用相同的动力学模型描述,有氢气存在时煤焦水蒸气气化的最终碳转化率低于纯水蒸气气化的最终碳转化率;氢气对煤焦水蒸气气化反应的抑制机理与氢气的分压范围有关,当氢气分压很低时,氢气的抑制作用主要是由于氢气离解生成的氢原子占据煤焦表面活性位所致,而当氢气分压很高时,氢气的抑制作用主要是由于氧交换反应的逆反应加强所致。

Effect of H2 on coa l-char gasification reaction with steam under pressure

The gasification characteristics of Huolinhe lignite char (HLH char), SM bituminous coal char (SM char) and Jincheng anthracite char (JC char) with the mixtures of steam and H₂ at elevated pressures were investigated in a pressurized fixed bed differential (PFBD) reactor. The results show that the inhibition of H₂ on the coal-char gasification with steam is remarkable, and the intensity of the inhibition increases with increasing H₂ partial pressure, total pressure and coal rank, respectively; while it decreases with increasing temperature. Coal-char gasification with steam or steam/H₂ can be described by the same kinetic model, and the final carbon conversion of coal-char gasification with steam/H₂ is lower than that with steam. The inhibition mechanism is related to the H₂ partial pressure. When H₂ partial pressure is low, H atom dissociated from H₂ molecule occupies the active point on the coal-char surface directly; while when the H₂ partial pressure is high, the irreversible reaction of oxygen-exchange reaction is strengthened.