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改性半焦烟气脱硫剂的物理结构和表面化学特性变化机理

Change Mechanism of Physical Structure and Surface Functional Groups of Activated Semi-Cokes used in SO2 Removal from Flue Gas

【作者】 上官炬

【导师】 李春虎;

【作者基本信息】 太原理工大学 , 化学工程与技术, 2006, 博士

【摘要】 我国是世界上一次能源生产和消费大国之一,从一次能源生产和消费结构来看,我国又是世界上以煤炭为主要能源的国家。煤炭大量的消耗,导致SO2大量排放,由排放的二氧化硫引起的酸雨损失又严重妨碍着我国可持续发展。同时,我国是世界上最大的农业国,每年要消耗大量的化肥。而化肥生产需要大量的硫酸,但我国是一个硫资源相对缺乏的国家,为了满足国内硫酸工业生产需求,每年从国外进口大量硫磺,花费巨额外汇。因此,研究具有中国特色的硫资源化烟气脱硫技术对我国经济可持续发展有重要意义。活性炭基材料烟气脱硫作为一种能同时脱硫、脱氮和回收硫资源的技术得到国内高度重视,但活性炭基材料制备的前驱物和改性过程都影响着活性炭基材料烟气脱硫剂工业应用。深入了解活性炭基材料前驱物、改性机理、物理织构和表面化学官能团变化以及构效关系、表面化学官能团脱硫作用机理等将有助于活性炭基材料烟气脱硫技术工业应用。 本论文选用内蒙古扎赉诺尔褐煤半焦作为活性炭基材料烟气脱硫剂的前驱物,利用水热化学、硝酸氧化和高温热处理三种改性方式以及它们之间多步组合改性方式制备出了系列改性半焦烟气脱硫剂。对原料半焦和改性半焦的工业组成、元素组成和无机氧化物含量以及表面总酸碱性官能团含量等进行了测试与分析。测试分析结果表明:原料半焦比传统活性炭含有较高的含氧官能团和较低的固定碳,以及含有以SiO2、Al2O3为主要无机氧化物组成的灰份,表面酸碱性官能团含量都较小,但表面碱性官能团含量明显高于表面酸性官能团含量;水热化学改性造成改性半焦表面酸性含氧官能团挥发,提高了表面碱性官能团含量;硝酸氧化改性在增加改性半焦样品表面含氧官能团含量的同时也提高了改性半焦表面含氮官能团含量,并且随着硝酸浓度增大而增大,硝酸氧化改性脱灰能力非常明显;高温热处理导致原料半焦的挥发份分解,明显提高了

【Abstract】 China is one of the largest country in the primary energy production and consumption in the world, and in primary energy production and consumption structure China regards coal as principle. The combustion of coal in massive amounts has produced a great quantity of air pollutants such as SO2. The damage and lose from the acid rain caused by the release of sulfur dioxide have severely baffled sustainable economic development of our country. On the other hand, China is the largest agriculture country in the world, a great deal of sulfuric acid has been produced to meet the needs of fertilizer industry production. However, the sulfur resources to meet the needs of domestic sulfuric acid production is relatively insufficient in our country and the sulfur has been imported in great quantities annually, which costs a huge sum of foreign exchange. Therefore, the investigation on SO2 removal from flue gas with sulfur recycling has great significance. SO2 removal from flue gas using activated carbonaceous material has been taken into account for removing SO2 and NOx simultaneously and recycling sulfur, but its industrial application was influenced by its precursor and modification process. To study the precursor, modification mechanism, physical texture, surface chemical functional groups, the relationship between texture and SO2 removal efficiency, and SO2 removal mechanism of surface chemical functional groups of activated carbonaceous material will contribute to industrial application of SO2 removal technology using activated carbonaceous material.In this paper, a series of activated semi-cokes were prepared from raw semi-coke from lignite in Inner Mongolia by means of hydrothermal treatment, HNO3 oxidation and heat treatment at high temperature as well as their combined modification. The proximate analysis, ultimate analysis, inorganic oxide content and surface acidic or basic groups content were carried on for raw semi-coke and the activated semi-coke samples. The analysis results show that, raw semi-coke is higher in oxygen-containing functional groups content and lower in fixed carbon content than traditional active carbon, including ash

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