基于不同循环特性吸收剂的直接制氢过程比较

COMPARISON OF DIRECTLY PRODUCTING HYDROGEN PROCESSES BASED ON SORBENTS WITH DIFFERENT CYCLIC CHARACTERISTICS

基于化石能源直接制氢中吸收剂的不同循环特性,分析由于石灰石和白云石循环特性差异导致的制氢过程中物流量和系统热平衡的变化,确定不同循环特性的吸收剂对整个制氢系统的热力学影响。研究结果表明,若加入同质量的吸收剂,过程A后续循环中CO2吸收不彻底,氢的含量持续降低,且气化器无法自身实现热平衡,过程B循环反应较稳定,吸收反应不完全,氢的含量较低,系统同样无法实现热平衡,过程C吸收剂的有效吸收成分(CaO)足量,系统可很好地实现热平衡,产物中氢的含量较高,但循环于系统中的惰性成分(MgO)的量较多,系统操作较困难,增加了系统的能量消耗。

Based on the different cyclic characteristics of the Ca-based CO2 sorbents in directly-producing hydrogen from fossil energy, three processes for hydrogen production were presented and the mass flow rate and the thermal equilibrium were analyzed to determine the effect of the different sorbents to the system. The research results showed that if dolomite and limestone with same quality are used in the hydrogen production process A and process B. CO2 is absorbed incompletely in the subsequent cycle of process A, making considerable reduction of H2 content, the reactor can not achieve thermal equilibrium itself and need outside heat source for heating in the process A; B cycle is relatively stable, but has the similar results with the process A. The effective absorbent （CaO） is sufficient in process C, and the system can achieve a good thermal equilibrium, and the hydrogen content is high in the production. However, there are more inert components （MgO） circulating in the system, which increase the energy consumption.