黏结性碎煤射流预氧化破黏与流化  

Caking property destruction and particle fluidization for caking coal in fluidized bed by jetting pre-oxidation

作　　者：赵飞翔[1,2] 赵志刚[1] 张聚伟[1] 曾玺[1] 初茉[2] 许光文[1] 

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《化工学报》2014年第6期1993-2002,共10页CIESC Journal

基　　金：中国科学院战略性先导科技专项(XDA07050400);国家自然科学基金项目(21306209)~~

摘　　要：具有黏结性（黏结性指数10-30）并高灰的劣质煤，如洗中煤难于适应于现有气化技术，但焦化等行业对这些煤的气化高价值利用具有极大的需求。中国科学院过程工程研究所提出了黏结性煤射流预氧化流化床气化技术，采用含氧气体向流化床气化炉稀相区喷射供料，有效破除煤的黏结性，同时强化气固接触和气化反应，实现对黏结性劣质煤的高效转化。采用小型射流预氧化流化床反应器，研究了黏结性指数为20的一种煤通过射流预氧化的破黏与实现流化的效果。分别考察了射流气过量空气系数（ER）和氧浓度（ O2C ）、加热炉设定温度（T）对预氧化破黏及煤颗粒流化的影响效果，分析了反应器内射流区的温度分布与生成气组成随时间的变化规律，并对预氧化后的半焦进行了电镜观测和气化反应活性测试及傅里叶红外分析。结果表明，在流化床中通过射流预氧化有效破黏、实现黏结性煤颗粒流化的工艺条件为：T＆gt;950℃， O2C =21%，ER ＆gt;0.1。在有效破黏的条件下射流区内的温度变化平稳，生成气中H2与CO含量较低，波动较小，而结焦条件下射流区内温度逐渐下降，生成气中H2与CO含量增加。经历结焦的半焦表面生成了黏结性物质，而经过预氧化成功破黏后的半焦其表面大部分官能团消失。The existing gasification technologies can hardly treat the coal like washing middlings that has caking index above 10 and also ash content, as high as above 40% （mass）. Coal industry, such as coking industry, however, has great need to gasify this kind of coal for realizing its value-added utilization. Institute of Process Engineering （IPE）, Chinese Academy of Sciences （CAS） proposed the jetting pre-oxidation fluidized bed gasification （JPFBG） to treat such a kind of coal. Coal particles are fed into the dilute zone of a fluidized bed reactor with a gas jet containing oxygen to implement the destruction of coal’s caking property. The jetting feed also strengthens gas-solids contact and accelerates gasification reaction. This study was devoted to characterizing＆amp;nbsp;the destruction of coal caking property via jetting feed of coal in a bench-scale fluidized bed with jetting pre-oxidation for a kind of powder coal with caking index of about 20. The tested parameters included equivalence ratio （ER） and O2 concentration （ O2C ） in the jetting gas and reaction temperature （T）. The results were analyzed in terms of time-series temperature in the reactor, time-series product gas composition and char characteristics given by SEM and FTIR analyses and gasification reactivity. The operational conditions for fully destroying the caking property of the tested coal were T＆gt;950℃, O2C =21% （vol） and ER＆gt;0.1. In this case the temperature in the feeding zone of the reactor was steady and the H2 and CO concentrations in the product gas were very low. Otherwise （caking occurred）, time-series temperature tended to decrease and the H2 and CO concentrations of product gas increased. Some adherent matters were identified on the surface of the char if caking occurred, whereas most of the functional groups disappeared from the char in the operation without occurrence of caking.

关 键 词：流化床 气化 黏结性煤 预氧化 破黏 

分 类 号：TQ530.2[化学工程—煤化学工程]