Chemical looping combustion of sewage sludge based on two-stage fuel reactor

doi:10.16085/j.issn.1000-6613.2017-1861

Abstract

Abstract: Chemical-looping combustion (CLC) is a promising technology with inherent CO₂ separation. A novel configuration with a two-stage fuel reactor for CLC was proposed in this paper. Hot experiments were performed with hematite as oxygen carrier and sewage sludge as fuel in this CLC unit. The total continuous operation time was more than 8 hours under stable condition. The effects of fuel reactor temperature (800-900℃) and fuel feed rate (300-600g/h) on chemical looping combustion of sewage sludge were investigated. The results showed that FR-S1 had a larger oxygen carrier inventory and the pressure fluctuation in the downcomer was extremely stable during the steady operation period. The design of two-stage fuel reactor was beneficial to improve the carbon conversion efficiency of the whole system. There was an increase in the carbon conversion efficiency and carbon capture efficiency with the rise of fuel reactor temperature. Oxygen demand was always less than 10%. Higher sewage sludge feed rate resulted in the decrease of carbon conversion efficiency and lower fraction of CO₂. XRD analysis of oxygen carrier extracted from the both fuel reactors showed that oxygen carrier in FR-S2 had more Fe₂O₃ compared with that in FR-S1 and thus led to higher reactivity.

Key words: two-stage fuel reactor, chemical looping combustion, sewage sludge, fluidized-bed, CO₂ capture, waste treatment

摘要： 化学链燃烧技术是一种可以实现CO₂内分离的新型燃烧技术。本文利用基于双级燃料反应器的新型化学链燃烧反应系统，以赤铁矿为载氧体，对污泥的化学链燃烧进行实验研究，系统连续稳定运行8h，考察燃料反应器温度（800～900℃）、污泥进料量（300～600g/h）对污泥化学链燃烧性能的影响。结果表明，稳定运行过程中，床料大部分位于一级燃料反应器，下降管高度保持稳定；双级燃料反应器的设计极大提高了污泥碳转化率，随温度的增加，碳转化率和碳捕集效率逐渐升高，且额外耗氧量始终低于10%；随着污泥进料量增加，碳转化率和CO₂体积分数逐渐降低。对两级燃料反应器内载氧体进行XRD分析，结果显示，还原后的载氧体在空气反应器再生后进入二级燃料反应器，和一级燃料反应器相比，具有更多的Fe₂O₃成分，保证其具有更高的反应活性。

关键词: 双级燃料反应器, 化学链燃烧, 污泥, 流化床, CO₂捕集, 废物处理

CLC Number:

WU Jian, SHEN Laihong, JIANG Shouxi, YAN Jingchun, SHEN Tianxu. Chemical looping combustion of sewage sludge based on two-stage fuel reactor[J]. Chemical Industry and Engineering Progress, 2018, 37(07): 2830-2836.

吴健, 沈来宏, 蒋守席, 闫景春, 沈天绪. 基于双级燃料反应器的污泥化学链燃烧特性[J]. 化工进展, 2018, 37(07): 2830-2836.

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