燃料化学学报（中英文）2025，Vol.53Issue(12)：1817-1829,13.DOI:10.3724/2097-213X.2025.JFCT.0016
生物质与煤共气化过程碱金属的迁移与转化
Migration and transformation of alkali and alkaline earth metals during co-gasification of biomass and coal
摘要
Abstract
This paper utilized a fixed-bed reactor to study the co-gasification process of sub-bituminous coal with two typical types of biomass(elm and cotton stalk).Through stepwise leaching experiments on gasification residual char under different gasifying agents(air and CO2)and different residence times,it systematically analyzed the migration and transformation patterns of alkali and alkaline earth metallic(AAEMs)elements with different occurrence modes.The research results indicate that the volatilization behavior of alkali metals can be divided into two characteristic stages:The first stage is the devolatilization stage during pyrolysis,during which the volatilization amount of alkali metal elements accounts for 40.74％-93.10％of the total volatilization;a significant amount of alkali metals is carried into the gas phase by the instantaneously released volatiles during pyrolysis.Within the reaction time of 0-5 min,the volatilization rate of potassium(K)in the coal/cotton stalk mixed sample under air atmosphere was 30％,and that of sodium(Na)was 32％,whereas the volatilization rate of K in the coal/elm mixed sample reached 49％;with increasing reaction temperature,the volatilization amount increased significantly.After extending the residence time to 5 min,the volatilization amount of K increased to 44％,and that of Na increased to 63％.Notably,calcium(Ca)in the coal/cotton stalk mixed sample under air atmosphere is more volatile than in the coal/elm sample,while the CO2 atmosphere significantly altered the volatilization characteristics of Ca.The second stage is the gas-solid reaction char-ash transition stage,during which the reaction rate is relatively slow;significant transformations in the occurrence modes of alkali and alkaline earth metallic elements(K,Ca,Na,Mg,etc.)occur through sustained contact between gasification semi-char and the gasifying agent(air or CO2).Within the residence time of 5-120 min,water-soluble K,insoluble K,and ammonium acetate-soluble K in the cotton stalk sample under air atmosphere progressively transformed into hydrochloric acid-soluble forms and the volatile phase;in the coal/elm mixed sample under air atmosphere,the hydrochloric acid-soluble Ca content decreased from 35％to 13％,while the proportion of the volatile phase increased from 11％to 27％.Concurrently,all occurrence forms of Na(including water-soluble,ammonium acetate-soluble,and residual forms)converted to the volatile phase.Magnesium(Mg)primarily existed in the ammonium acetate-soluble form(55％),with minimal variation in its occurrence mode over residence time.With prolonged residence time,K and Ca combined with elements such as S,Al and Si under air atmosphere to form stable compounds like CaSO4 and KAlSiO4;whereas under CO2 atmosphere,characteristic components such as CaCO3,CaS and MgS were predominantly generated.关键词
生物质/共气化/AAEMs/赋存形态Key words
biomass/co-gasification/AAEMs/occurrence form分类
能源科技引用本文复制引用
梁阳,许晓兵,李涛,沈中杰,亚力昆江·吐尔逊,高干,钟梅,代正华,李建,刘洋,张显显,袁万能..生物质与煤共气化过程碱金属的迁移与转化[J].燃料化学学报（中英文）,2025,53(12):1817-1829,13.基金项目
The project was supported by R&D Project of Xinjiang Uyghur Autonomous Region(2022B03026-1),Natural Science Foundation of Xinjiang Uygur Autonomous Region(2023D01D02)and Open Project Program of State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resource(KFKT2022ZD-00002-1).新疆维吾尔自治区重点研发计划(2022B03026-1),新疆维吾尔自治区自然科学基金(2023D01D02)和省部共建碳基能源资源化学与利用国家重点实验室开放课题(KFKT2022ZD-00002-1)资助 （2022B03026-1）
