This study aimed to investigate the mechanism of nitrogen doping,migration,and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose.The results showed that t...This study aimed to investigate the mechanism of nitrogen doping,migration,and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose.The results showed that the ammonia torrefaction pretreatment could significantly optimize the distribution of nitrogen and oxygen elements in cellulose.The carbon skeleton first captured the active nitrogenous radicals to form-NHn-N,and pyridine-N and pyrrole-N originated from the conversion of-NHn-N.The existence of C=O played a major role in the immobilization of nitrogen.The nitrogen in bio-oil exists mainly in the form of five-and six-membered heterocycles.The correlation analysis showed that the main precursors for the formation of nitrogenous heterocyclic compounds were five-membered Oheterocyclic compounds.Finally,the product distribution characteristics in the torrefaction-pyrolysis systems were summarized,and the nitrogen doping and conversion mechanisms were proposed.This study expanded the boundaries of cellulose pretreatment and the production of high-value chemicals.展开更多
Coal sludge is a seriously polluted solid waste,and the rational utilization of its resources has long being an undoubtedly important research topic.This paper mainly studies the coal sludge partial preheating charact...Coal sludge is a seriously polluted solid waste,and the rational utilization of its resources has long being an undoubtedly important research topic.This paper mainly studies the coal sludge partial preheating characteristic,combustion characteristic and the process of migration and conversion of nitrogen with preheating combustion technology.The experimental results indicate that most of the elements in the coal sludge are released during preheating,and the ratio of the fuel-N converted to the N_(2),NH_(3) and HCN are 75.5%,6.74%and 0.64%,respectively.Compared with the coal sludge,the BET surface area and cumulative pore area of preheated char are increased.The surface of preheated char is loose and porous with many fine particles,while raw coal is dense with larger particles.Meantime,the quantity of carbon defect structure,the active sites and the reactivity of preheated char are all increased.In the whole process,the NO_(x) emission is about 156 mg/m3(@6%O2),the ratio of fuel-N converted to NO_(x) was 2.98%,and the combustion efficiency is 96.5%.This experiment results will play a vital role in efficient and clean utilization of coal sludge.展开更多
基金sponsored by the National Natural Science Foundation of China(52176193)the National Key Research and Development Program of China(2019YFD1100602)+1 种基金the Shandong Provincial Natural Science Foundation,China(ZR2020ME184)the SDUT & Zhangdian City Integration Development Project(2021JSCG0013)。
文摘This study aimed to investigate the mechanism of nitrogen doping,migration,and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose.The results showed that the ammonia torrefaction pretreatment could significantly optimize the distribution of nitrogen and oxygen elements in cellulose.The carbon skeleton first captured the active nitrogenous radicals to form-NHn-N,and pyridine-N and pyrrole-N originated from the conversion of-NHn-N.The existence of C=O played a major role in the immobilization of nitrogen.The nitrogen in bio-oil exists mainly in the form of five-and six-membered heterocycles.The correlation analysis showed that the main precursors for the formation of nitrogenous heterocyclic compounds were five-membered Oheterocyclic compounds.Finally,the product distribution characteristics in the torrefaction-pyrolysis systems were summarized,and the nitrogen doping and conversion mechanisms were proposed.This study expanded the boundaries of cellulose pretreatment and the production of high-value chemicals.
基金This study is supported by“Transformational Technologies for Clean Energy and Demonstration”,Institute of Engineering Thermophysics Chinese Academy of Sciences,Grant No.XDA21040100.
文摘Coal sludge is a seriously polluted solid waste,and the rational utilization of its resources has long being an undoubtedly important research topic.This paper mainly studies the coal sludge partial preheating characteristic,combustion characteristic and the process of migration and conversion of nitrogen with preheating combustion technology.The experimental results indicate that most of the elements in the coal sludge are released during preheating,and the ratio of the fuel-N converted to the N_(2),NH_(3) and HCN are 75.5%,6.74%and 0.64%,respectively.Compared with the coal sludge,the BET surface area and cumulative pore area of preheated char are increased.The surface of preheated char is loose and porous with many fine particles,while raw coal is dense with larger particles.Meantime,the quantity of carbon defect structure,the active sites and the reactivity of preheated char are all increased.In the whole process,the NO_(x) emission is about 156 mg/m3(@6%O2),the ratio of fuel-N converted to NO_(x) was 2.98%,and the combustion efficiency is 96.5%.This experiment results will play a vital role in efficient and clean utilization of coal sludge.
