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单颗粒煤粉热解时焦油的二次反应和扩散
  • ISSN号:1000-0054
  • 期刊名称:《清华大学学报:自然科学版》
  • 时间:0
  • 分类:TQ534[化学工程—煤化学工程]
  • 作者机构:清华大学热能工程系,热科学与动力工程教育部重点实验室,北京100084
  • 相关基金:国家自然科学基金项目(51176096)~~
作者: 张盛诚, 何榕
中文摘要:

为了深入研究煤焦燃烧的机理并提高对煤焦燃烧过程的预测精度,建立了一个综合的煤焦燃烧模型。该模型考虑了煤焦颗粒孔隙内二次反应与扩散的耦合作用、煤焦燃烧反应阶数的变化和反应过程中CO/CO2比例等问题。使用热天平(TGA)对11种煤焦的燃烧特性进行分析,测得各种煤焦的表观活化能与指前因子,以确定模型中的待定参数。在沉降炉(DTF)中对这11种煤焦做燃烧实验,用TGA基于灰分守恒测得DTF炉管出口处的煤焦样品的转化率。运用建立的模型模拟这些煤焦的燃烧过程,预测的转化率与实验结果有较好的吻合度,相比传统的本征动力学模型,该模型预测的精度有了较大提高,证明了该模型能适用于从褐煤到无烟煤的较广煤焦范围。研究还发现,煤焦燃烧的表观反应阶数在燃烧过程中不断减小并最终趋于稳定。

英文摘要:

A fractal char particle combustion model was developed to study the char combustion mechanism and improve the prediction accuracy of the char combustion characteristics. This model considered the coupling effects of the secondary reactions and gas diffusion within the char pores. The apparent reaction order of char combustion changed with the particle temperature, the O2 partial pressure at the particle surface and the particle pore structure parameters instead of keeping constant 1. The primary CO/CO2 ratio was obtained by theoretical derivation. The combustion characteristics of eleven different chars were analyzed by a thermogravimetric analyzer(TGA) with their apparent activation energies and pre-exponential factors measured which were used to solve the undetermined model parameters. These chars were also combusted in a drop tube furnace(DTF) and the char samples were collected at the outlet of the DTF. The conversions of these char samples were measured by TGA based on the ash conservation method. The combustion processes of these chars were simulated by this model. The predicted char conversions by this model were matched very well with the measured data and the accuracy was significantly improved compared with the intrinsic model, proving that this model had good accuracy over a wide range of char particles from lignite to anthracite. The study also showed that the apparent reaction order of char combustion first decreased and then gradually stabilized in the char combustion process.

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期刊信息
  • 《清华大学学报:自然科学版》
  • 中国科技核心期刊
  • 主管单位:教育部
  • 主办单位:清华大学
  • 主编:梁恩忠
  • 地址:北京市海淀区清华大学学研大厦B座908
  • 邮编:100084
  • 邮箱:xuebaost@tsinghua.edn.cn
  • 电话:010-62788108 62792976
  • 国际标准刊号:ISSN:1000-0054
  • 国内统一刊号:ISSN:11-2223/N
  • 邮发代号:2-90
  • 获奖情况:
  • 国家期刊奖,国家“双高”期刊,1992年以来,历次国家级和省部级一等奖,第一、二届全国优秀科技期刊一等奖,教育部优秀期...,第三届中国出版政府奖提名奖
  • 国内外数据库收录:
  • 美国化学文摘(网络版),美国数学评论(网络版),德国数学文摘,荷兰文摘与引文数据库,美国工程索引,美国剑桥科学文摘,日本日本科学技术振兴机构数据库,美国应用力学评论,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),中国北大核心期刊(2000版)
  • 被引量:43470