新型层状双氢氧化物阻化剂抑制煤氧化的特性研究

发布时间：2018-05-05 02:16

本文选题：煤自燃 + 层状双氢氧化物　；参考：《西安科技大学》2017年硕士论文

【摘要】：层状双氢氧化物(LDHs)是一种无卤无磷多功能无机材料,具有高效、环保、安全、抑烟,受热分解释放水蒸汽和二氧化碳等优势,可作为新型煤自燃阻化剂。但是,目前层状双氢氧化物阻化剂的研究还处于初级阶段。本文合成了一种新型层状双氢氧化物阻化剂,研究了其对不同变质程度煤自燃的阻化特性及机理,对于该阻化剂的工业应用具有一定的指导意义。本文采用原位共沉淀法制备了一种ZnMgAl-CO3-LDHs层状双氢氧化物阻化剂,利用热重和气体红外光谱的测试手段对样品结构特性进行了分析,得出该类阻化剂氧化分解吸热,并释放出大量的水蒸气和二氧化碳气体。表明层状双氢氧化物具有延缓煤自燃氧化升温,和降低煤表面氧浓度的特性。选取不同变质程度的四种煤样(神府长焰煤和不粘煤、新疆焦煤、阳泉无烟煤),与制备出的阻化剂按设定比例混合,机械搅拌均匀制成阻化煤样。采用热重/差示扫描量热-傅里叶变换红外光谱(TG/DSC-FTIR)联用分析技术,对添加不同比例的该层状双氢氧化物阻化剂煤样进行研究。TG曲线反映的临界温度、干裂温度、着火点温度等煤自燃特征温度,添加阻化剂煤样均高于原煤样,其中当阻化剂添加量为20%时升高量最大。各样品DSC曲线上均出现放热峰。添加阻化剂煤样放热峰面积明显小于原煤样。说明这种ZnMgAl-CO3-LDHs层状双氢氧化物阻化剂在升温过程中多级吸热,能够有效的抑制煤的氧化自燃。气体红外光谱分析显示,阻化煤样氧化放出的CO和CO2的量明显减少,且阻化剂添加量越多,这些氧化气体产生量越小。根据热重分析结果,研究了原煤与阻化煤样升温氧化过程的反应活化能,表明活化能随阻化剂添加量增加而增大。因此,ZnMgAl-CO3-LDHs层状双氢氧化物阻化剂对不同变质程度煤样均具有良好的阻化效果,尤其对长焰煤和不粘煤阻化效果更佳。阻化煤样活化能增加,说明该层状双氢氧化物阻化剂可能改变了煤氧化反应的类型或进程,从而起到一定化学阻化作用。
[Abstract]:Layered double hydroxide (LDHs) is a non-halogen and phosphorus-free multifunctional inorganic material, which has the advantages of high efficiency, environmental protection, safety, smoke suppression, thermal decomposition and release of water vapor and carbon dioxide, etc. It can be used as a new type of coal combustion resistance agent. However, the study of layered double hydroxide inhibitors is still in the primary stage. In this paper, a new layered double hydroxide inhibitor has been synthesized, and its inhibition characteristics and mechanism to the spontaneous combustion of coal with different metamorphic degrees have been studied, which is of certain guiding significance for the industrial application of this inhibitor. In this paper, a ZnMgAl-CO3-LDHs layered double hydroxide inhibitor was prepared by in-situ coprecipitation method. The structure characteristics of the sample were analyzed by thermogravimetry and gas infrared spectroscopy, and the results showed that the oxidation decomposition of the inhibitor was endothermic. And release a lot of water vapor and carbon dioxide gas. The results show that the layered double hydroxides can delay the spontaneous combustion of coal and decrease the oxygen concentration on the coal surface. Four kinds of coal samples with different degrees of metamorphism (Shenfu long flame coal and non-caking coal, Xinjiang coking coal, Yangquan anthracite coal) were mixed with the prepared antidote according to the set proportion, and the mechanical stirring was used to make the blocking coal samples. The TGA / DSC-FTIR analysis technique was used to study the critical temperature and dry cracking temperature of the coal sample with different proportion of the layered double hydroxide inhibitor. The characteristic temperature of spontaneous combustion of coal, such as ignition point temperature, is higher than that of raw coal sample, especially when the amount of inhibitor is 20. Exothermic peaks appeared on the DSC curves of all samples. The exothermic peak area of coal sample added with inhibitor is obviously smaller than that of raw coal sample. The results show that this ZnMgAl-CO3-LDHs layered double hydroxide inhibitor can effectively suppress the oxidation spontaneous combustion of coal in the process of heating. The analysis of gas infrared spectrum shows that the amount of CO and CO2 released from the oxidation inhibition of coal samples is obviously reduced, and the more the amount of inhibitor is added, the smaller the production of these oxidized gases is. Based on the results of thermogravimetric analysis, the reaction activation energy of the oxidation process between the raw coal and the block coal is studied. It is shown that the activation energy increases with the increase of the amount of inhibitor. Therefore, ZnMgAl-CO3-LDHs layered double hydroxide inhibitor has good inhibition effect on different metamorphic coal samples, especially for long flame coal and non-caking coal. The increase of activation energy of coal samples indicates that the layered double hydroxide inhibitor may change the type or process of coal oxidation reaction and thus play a certain role in chemical inhibition.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD752.2

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