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低阶煤热解-气化-燃烧TBCFB系统模拟及优化

王亚雄1 杨景轩1 张忠林1 马旭莉1 李鹏2 郝晓刚1 官国清3

(1.太原理工大学化学化工学院, 山西太原 030024)
(2.太原科技大学化学与生物工程学院, 山西太原 030021)
(3.日本国立弘前大学北日本新能源研究所, 日本青森030-0813)

【摘要】三塔式循环流化床 (TBCFB) 是基于低阶煤分质转化利用理念开发的新型工艺系统, 包含热解、气化及燃烧三个主反应器。提出了采用半焦颗粒代替石英砂作为循环热载体的新工艺, 并使用Aspen Plus建立了基于半焦颗粒的TBCFB系统模拟流程, 寻求系统内物料转化和能量利用的适宜操作条件。结果表明, 只需燃烧40%的热解半焦, 即可满足低阶煤在600℃热解和60%的热解半焦在800.9℃进行水蒸气气化所需热量;与石英砂或高温灰相比, 利用热容较高的半焦颗粒作为循环介质可以显著降低热载体循环量, 与原煤质量比仅为5.5。综合气化产物组成、低热值和冷煤气效率等指标, 适宜的水蒸气与反应半焦质量比为1.5。上述模拟结果对半焦循环TBCFB新技术的工业应用具有一定指导意义。

【关键词】 分质利用;循环流化床;模拟;气化;优化;

【DOI】

【基金资助】 国家自然科学基金项目 (21506139, U1710101) ;

TBCFB system simulation and optimization for pyrolysis-gasification-combustion of low rank coal

WANG Yaxiong1 YANG Jingxuan1 ZHANG Zhonglin1 MA Xuli1 LI Peng2 HAO Xiaogang1 GUAN Guoqing3

(1.College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China 030024)
(2.College of Chemistry and Biological Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi, China 030021)
(3.North Japan Research Institute for Sustainable Energy (NJRISE), Hirosaki University, Aomori 030-0813, Japan)

【Abstract】The quality-based utilization technology of low rank coal has attracted much attention due to its advantages in energy saving and emission reduction. A novel triple-bed combined circulating fluidized bed (TBCFB) system, which includes a pyrolyzer, a gasifier and a combustor, is developed to minimize energy loss. A new process is proposed to use char particles instead of sand particles as heat-carried circulating medium and an Aspen Plus process simulation is established to obtain optimum operating conditions for material conversion and energy utilization among three bed reactors. The results show that 40% char combustion can provide enough energy for both low rank coal pyrolysis at 600 °C and gasification of water over 60% residual char at 800.9 °C. The high-heat-capacity char particles significantly reduce the amount of heat-carried particles needed to circulate in the system. To meet the requirements of heat transportation, the mass ratio of char to low rank coal is 5.5, whereas the mass ratios of quartz and ash to low rank coal are 11 and 12, respectively. Comprehensive analysis of syngas composition, cold gas efficiency (CGE) and lower heating value (LHV) indicates that the optimal ratio of steam to char (St/C) is 1.5 in gasification. The simulation results provided some guidance on the industrial application of TBCFB system with char as heat-carried particles.

【Keywords】 quality-based utilization; circulating fluidized bed; simulation; gasification; optimization;

【DOI】

【Funds】 National Natural Science Foundation of China (21506139, U1710101) ;

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This Article

ISSN:0438-1157

CN: 11-1946/TQ

Vol 69, No. 08, Pages 3596-3604+3764

August 2018

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Article Outline

Abstract

  • Introduction
  • 1 TBCFB process introduction and model establishment
  • 2 Process establishment and model verification
  • 3 Results and discussion
  • 4 Conclusion
  • Symbol illustration
  • References