College of Chemistry and Chemical Engineering, Xi’an Shiyou University
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences

生物质中碱金属的催化作用是引起共气化协同作用的根本原因。然而,共气化过程中碱金属易与煤中矿物质反应生成硅铝酸盐等没有催化活性的物质,导致不能发挥出有效的催化作用。因此为了部分抑制共气化过程中生物质碱金属的失活,强化协同作用,通过固定床热解、共热解焦水蒸气气化实验,考察了小麦秸秆和晋城无烟煤共气化过程的反应性和协同作用,并通过添加钙基添加剂的方式,强化了协同作用,提高了共气化反应速率。研究发现共热解焦在气化过程中虽然表现出协同作用,但仍然存在K的失活。考察了钙基添加剂的种类、添加量、添加顺序等对共气化反应的影响,结果表明:钙基添加剂使共热解焦比表面积增大,碳结构无序化程度增强,活性位点增多,并通过与煤中SiO2等矿物质的结合,部分阻止了K的失活,使共热解焦中水溶性K含量升高,反应速率提高。Ca(Ac)2表现出最优的共气化反应促进作用,其最优添加量为7.5%。气化反应动力学的研究表明,Ca(Ac)2的添加降低了共热解焦的气化反应活化能。修正随机孔模型(S-MRPM)适合描述小麦秸秆焦、晋城煤焦和共热解焦的气化反应特性,随机孔模型(RPM)适合对添加Ca(Ac)2的共热解焦进行动力学分析。

The catalytic role of alkali metals in biomass is the fundamental reason for the synergistic effect in co-gasification. However, the presence of minerals in coal can result in the deactivation of these alkali metals by forming some non-catalytic compounds, such as aluminosili-cates, inhibiting their catalytic effect. Therefore, in order to partially suppress the deactivation of biomass alkali metals and enhance the synergistic effect during co-gasification, the co-gasifica-tion reactivity and synergy effect of wheat straw and Jincheng anthracite were investigated in this study by conducting the steam gasification of the co-pyrolyzed char in a fixed bed reactor. Calci-um-based additives were incorporated in order to enhance the synergy effect and improve the co-gasification rate. The gasification behavior of the co-pyrolyzed char was studied, revealing the presence of synergy and undesirable K deactivation phenomenon in all gasification tests. Mean-while, the effects of calcium-based additive type, adding amount, and loading method on co-gasi-fication reactivity were explored. The results show that calcium-based additives can lead to a lar-ger surface area, a stronger amorphous structure, and more active sites of the co-pyrolyzed char. Moreover, the reaction between Ca and SiO2 can prevent the reaction between partial K and the minerals in coal, thereby increasing the water-soluble K content and co-gasification rate. Among the calcium-based additives studied, Ca(Ac)2 exhibits the best promotion effect on co-gasifica-tion, with an optimal addition of 7.5%. Gasification kinetics analysis illustrates that the addition of Ca(Ac)2 can reduce the activation energy of co-gasification. Besides, S-MRPM (shifted modi-fied random pore model) can satisfactorily predict the gasification behaviors of wheat straw char, Jincheng anthracite char, and co-pyrolyzed char. RPM (random pore model) can aptly describe the co-pyrolyzed char gasification with Ca(Ac)2 addition.

国家自然科学基金项目(21908176,21878243)和西安石油大学研究生创新与实践能力培养计划项目(YCS21112062).

丁 亮,阮 云,白 斌,等.生物质/煤共气化协同作用的产生及强化机制[J].煤炭转化,2023,46(6):43-56

DOI:10.19726/j.cnki.eb-cc.202306005.DING Liang,RUAN Yun,BAI Bin,et al.Generation and reinforcement mechanism of synergy effect of co-gasification of biomass and coal[J].Coal Conversion,2023,46(6):43-56