基于CuMn 2O 4载氧体的生物质化学链气化热力学分析

Thermodynamic Analysis on Chemical Looping Gasification of Biomass With the CuMn2O4 Oxygen Carrier

建立了以CuMn 2O 4为载氧体、松木屑为燃料的生物质(B)化学链气化模型,对CuMn 2O 4载氧体和松木屑之间的化学链气化反应进行了热力学模拟。研究了气化过程中CuMn 2O 4载氧体的还原过程,考察了燃料反应器内载氧体与生物质摩尔比(n(O)/n(B))、反应温度、水蒸气与生物质摩尔比(n(H 2O)/n(B))、CO 2与生物质摩尔比(n(CO 2)/n(B))等因素对气化反应的影响,分析了空气反应器内载氧体晶格氧的恢复过程。热力学分析表明:CuMn 2O 4在气化反应中可以提供晶格氧,有效促进松木屑的气化。CuMn 2O 4载氧体中的Cu和Mn组分在化学链气化反应中分别按照CuO→Cu 2O→Cu和Mn 2O 3→Mn 3O 4→MnO的顺序逐级被还原,并且Mn 2O 3优先CuO被还原。以气化系统的碳转化率和合成气产量为主要评价指标,优化的反应条件为:n(O)/n(B)为0.16,反应温度为1273 K,n(H 2O)/n(B)为0.40,n(CO 2)/n(B)为0.20。在空气反应器内,CuMn 2O 4载氧体还原后失去的晶格氧经空气氧化后可以恢复到初始状态。

A model of biomass chemical looping gasification was built using CuMn 2O 4 as the oxygen carrier and pine sawdust as the fuel,and the thermodynamic analysis of the gasification was performed.The reduction of the oxygen carrier was investigated,and the effects of the molar ratio of oxygen carrier to biomass(n(O)/n(B)),reaction temperature,the molar ratio of steam to biomass(n(H 2O)/n(B))and the molar ratio of CO 2 to biomass(n(CO 2)/n(B))on gasification characteristics were detailedly discussed.The oxidation process of the reduced oxygen carrier was also analyzed.Thermodynamic analysis indicates that CuMn 2O 4 provides lattice oxygen to improve the conversion of pine sawdust effectively.Cu and Mn constituents in CuMn 2O 4 oxygen carrier are reduced with the order of CuO→Cu 2O→Cu,and Mn 2O 3→Mn 3O 4→MnO,respectively.The reduction of Mn 2O 3 is prior to that of CuO.The carbon conversion efficiency and gas yields were used as evaluation indicators,and the results show that system performs best when n(O)/n(B),reaction temperature,n(H 2O)/n(B),n(CO 2)/n(B)are 0.16,1273 K,0.40 and 0.20,respectively.The reduced oxygen carrier has been oxidized to the initial state in the air reactor.