摘要
利用数值模拟技术,深入探讨了固定床反应器中不同水分质量分数对煤热解特性的影响。采用双流体模型结合Zehner-Bauer-Schlunder(ZBS)气固相间导热模型、Breitbach-Barthels(B-B)辐射模型、相变模型、煤热解平行反应动力学模型和焦油二次裂解模型,模拟了煤在固定床反应器中的传热、传质及热解反应过程,分析了不同水分质量分数对煤热解产物生成的影响。模拟结果表明,不同径向位置挥发分生成速率最大时对应的温度都接近热解终温。水分质量分数影响了反应器内的温度分布、挥发分生成速率以及各热解产物的产率。随水分质量分数的增加,煤层升温速度减慢,煤层中心达到热解温度的时间显著延长,热解过程推迟,降低了热解效率。同时,高水分煤的热解产物总体生成速率也有所下降,尤其是挥发分的生成受到了抑制。此外,水分质量分数的增加影响了各热解产物的产率:热解气和热解水的产率上升,焦油和半焦的产率下降。该研究得到了含水率对煤热解行为的影响规律,为优化煤热解工艺、提高煤炭转化效率提供了理论依据。
This study utilized numerical simulation techniques to investigate the pyrolysis characteristics of coal with varying moisture content in an externally-heated fixed-bed reactor.The two-fluid model was combined with Zehner-Bauer-Schlunder(ZBS)thermal conductivity model,Breitbach-Barthels(B-B)radiation model,phase transformation model,parallel reaction kinetics model of coal pyrolysis and secondary pyrolysis model of tar,to simulate the heat transfer,mass transfer and pyrolysis processes of coal in a fixed bed reactor.The effects of different moisture content on the generation of coal pyrolysis products were analyzed.The results show ed that the temperature approach ed terminal pyrolysis temperature when the volatilization rate reache d maximum at different radial position.The water content affe cted the temperature distribution,the rate of volatilization and the yield of pyrolysis products in the reactor.With the increase of moisture content,the heating rate of coal seam slow ed down,the time for coal seam center to reach the pyrolysis temperature was significantly extended,the pyrolysis process was delayed,and the pyrolysis efficiency was reduced.At the same time,the overall generation rate of pyrolysis products of high-moisture coal also decrease d,especially the generation of volatiles was inhibited.In addition,the increase of moisture content affec ted the yield of each pyrolysis product.T he yield of pyrolysis gas and pyrolysis water increas ed,while the yield of tar and semi-coke decreas ed.This study obtai ned the law of the influence of moisture content on coal pyrolysis behavior,which provi ded a theoretical basis for optimizing coal pyrolysis process for further improving coal conversion efficiency.
作者
王蓝欣
李飞
钱亚男
田于杰
申峻
王维
WANG Lanxin;LI Fei;QIAN Yanan;TIAN Yujie;SHEN Jun;WANG Wei(College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;State Key Laboratory of Mesoscience and Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;School of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;National Key Laboratory of Chemical Safety,SINOPEC Research Institute of Safety Engineering Co.,Ltd.,Qingdao 266000,Shandong,China)
出处
《化工进展》
北大核心
2025年第8期4513-4525,共13页
Chemical Industry and Engineering Progress
基金
国家重点研发计划(2022YFC3902505,2024YFB4105902)
国家自然科学基金(22208351,22161142006,51876212)。
关键词
煤热解
含水率
反应动力学
数值模拟
coal pyrolysis
moisture content
reaction kinetics
numerical simulation
