洁净煤技术

2019, (05) 30-38

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低焦油固定床气化研究进展
Research progress on low tar fixed bed gasification

臧雪晶;陈亚飞;董卫果;读刚;郭良元;
ZANG Xuejing,CHEN Yafei,DONG Weiguo,DU Gang,GUO Liangyuan

摘要(Abstract):

随着环保要求日趋严格,固定床气化焦油引起的环境问题成为制约固定床气化技术发展的瓶颈,低焦油气化应得到重视。本文介绍了固定床气化中实现低焦油气化的途径及影响因素,分析了各工艺条件对焦油产量的影响,阐述了两段炉、下吸式炉型以及两段供风式气化炉降低焦油的原理。较为普遍的是将下吸式与两段式气化炉相结合,生成的焦油含量低,燃气热量高,炉内热量损失率低,多用于生物质气化技术开发。喉口结构既能增加气速,又能提高炉内温度,促进炉内焦油裂解。气化原料、粒径、气化工艺(气化终温、压力、气化剂、催化剂等)是影响焦油产率的重要因素。高挥发分的气化原料(低阶煤、生物质等)生成的焦油较多,挥发分较低的高阶煤焦油含量很少。粒径影响挥发分析出与传热,从而影响焦油产率。温度的影响主要在于焦油裂解,焦油裂解占裂解反应的主反应时,随温度上升,焦油产率逐渐降低,因此,部分催化剂与后续脱焦油技术需根据温度对焦油的热裂解作用来降低焦油含量。增大压力会抑制挥发分析出,有利于减少焦油。通入适量水蒸气能降低焦油含量,增加氢气含量,但会降低气化温度,需进行定量参数调节。各种催化剂能有效降低焦油含量且改变煤气热值,但催化剂反应条件严格,会增加气化成本。低焦油气化能产生清洁的新能源,是固定床气化技术的重要突破,既能提高低阶煤利用率,又能解决高挥发分的生物质、城市垃圾气化问题。煤气中焦油含量减少,有效气体成分提高,有效缓解低热值气化原料产气热值过低的问题。
Abstract:With the increasingly strict requirements of environmental protection,the environmental problems caused by the fixed bed gasification tar have become a bottleneck for restricting the development of fixed bed gasification technology,and low tar gasification should be paid more attention to. This paper introduces the approach and influencing factors of low tar gasification in fixed bed gasification,analyzes the influence of various technological conditions on tar yield,and expounds the principle of reducing tar in two-stage gasifier,downdraft gasifier and two-stage air supply gasifier. It is more common to combine downdraft gasifier with two-stage gasifier to produce low tar content,high gas heat,low heat loss rate in the furnace,which is mostly used for biomass gasification technology development. The throat structure can not only increase the gas velocity,but also increase the temperature in the blast furnace and promote tar cracking in the furnace. Gasification raw materials,particle size,gasification process(gasification final temperature,pressure,gasification agent,catalyst,etc.)are important factors of affecting the yield of tar. The high volatile gasification raw materials(low rank coal,biomass,etc.)produce more tar,and the content of low volatile high rank coal tar is very little. The particle size affects volatile analysis precipitation and heat transfer,which affects tar yield. The influence of temperature mainly lies in tar cracking. When the tar cracking occupies the main reaction position of cracking reaction,the yield of tar gradually decreases with the rise of temperature. Therefore,some catalysts and subsequent de-tar technology need to reduce the tar content according to the thermal cracking effect of temperature on tar. Increasing pressure will inhibit volatile analysis,which is conducive to reducing tar. The suitable amount of water vapor can reduce tar content,and increase the hydrogen content,but will reduce the gasification temperature,and the quantitative parameters need to be adjusted. Various catalysts can effectively reduce the tar content and change the heat value of gas,but the strict catalyst reaction conditions will increase the cost of gasification. The realization of low tar gasification is an important breakthrough in fixed-bed gasification technology,which can not only improve the utilization rate of low-rank coal,but also solve the problem of high volatile biomass and urban waste gasification,and generate clean new energy. The content of tar in gas is reduced,the effective gas composition is increased,which can alleviate the problem of low heat value of gasification raw material.

关键词(KeyWords): 低焦油;固定床气化;煤焦油产率;影响因素
low tar;fixed bed gasification;coal tar yield;influencing factors

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作者(Author): 臧雪晶;陈亚飞;董卫果;读刚;郭良元;
ZANG Xuejing,CHEN Yafei,DONG Weiguo,DU Gang,GUO Liangyuan

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