煤基固体洁净燃料中金属复合物对热解-燃烧中氮化物污染物两步控制耦合作用机理

The NOx pollutant released by the combustion of bulk coal in China has harmful influence on ecological environment. According to the action plan of clean and efficient utilization of coal, the research on coal-based clean fuel instead of bulk coal play an important role in the consumption structure of coal energy. we put forword a technology obtained bulk coal substitutes-coal based clean fuel with low emission of NOx pollutant , which prepared from low rank coal by the removal of nitrogen in coal high temperature pyrolysis (dry distillation) combined the denitration in coal based high temperature combustion. This project will research the influences of metal compound on migration rule of nitrogen compounds during coal high temperature pyrolysis (dry distillation), and conclude the mechanism of orienteering removal of nitrogen by high temperature pyrolysis. Also, the influences of metal compound on migration rule of nitrogen compounds during coal high temperature combustion will be researched and the mechanism of in situ denitration by high temperature combustion will be concluded. Finally, the coupling effect between the catalysis cracking removal of nitrogen in coal high temperature pyrolysis and catalysis reduction denitration in coal based clean fuel combustion by step to join metal compounds will be researched. This researches will supply theoretical basis for the clean and efficient utillization of low-rank coal, make a contribution to theoretical study on environmental protection in the utillization of coal, and have a significant role in the promotion of non coking coal utilization value and accelerating the transformation of coking industry.

我国散煤燃烧释放的NOX污染物对生态环境影响巨大。依据煤炭清洁高效利用行动计划，研究低阶煤制煤基固体洁净燃料替代散烧煤意义重大。我们提出通过低阶煤高温热解（或干馏）制备固体燃料过程中减氮，联合固体燃料燃烧过程中脱硝两步，来实现低阶煤应用中氮化物污染物的减排，获得散烧煤的替代品-煤基固体洁净燃料。研究金属复合物催化剂对煤高温热解（干馏）过程煤中氮化物迁移规律及影响因素，推断金属复合物在高温热解定向减氮机理；研究金属复合物催化剂对煤基固体燃料燃烧过程中氮化物迁移规律及影响因素，推断金属复合物在高温燃烧原位脱硝机理；揭示一步添加金属复合物在煤高温热解定向催化裂解减氮-煤基固体洁净燃料燃烧原位催化还原脱硝两步中控制氮氧化物污染物释放的耦合作用。研究将为低阶煤高效洁净利用提供理论依据，为煤炭利用环境保护理论研究作出贡献，对提升非炼焦煤的利用价值，加速焦化产业转型发展产生重大作用。

本项目的主要研究内容为：①原料煤中氮化物的形态及分布规律；②金属复合物对煤热解（干馏）中氮化物迁移规律的影响；③金属复合物在煤热解（干馏）中定向降低焦氮的机理；④金属复合物对燃烧中气相氮化物类型及分布规律的影响及气氛效应；⑤金属复合物在洁净燃料燃烧中原位脱硝的机理；⑥金属复合物对热解-燃烧NOx两步控制耦合作用机理。.重要结果为：原料煤中氮化物主要以吡咯环，吡啶环，季氮和氮氧化物四种形态存在。采用酸洗脱灰、溶胀方法对高硫煤、长焰煤、褐煤等不同煤种预处理，并利用物理混合、浸渍法得到含铁、钴、镍、铈等化合物的研究样品。通过对煤热解过程中固、液、气三相氮平衡及XPS氮化物形态分析表明，助剂可催化燃料氮裂解及加氢，促进固相氮向气相氮迁移，并提高环境友好的N2生成。量子化学计算进一步表明，结构不同会导致分解难易程度不同，N2的生成来源于更稳定的含氮结构的裂解，助剂主要通过增加碳质表面的活性，缩短热解生成N2的路径，降低反应决速步能垒来促进N2生成。煤燃烧过程中生成的NOx是燃料氮氧化及NOx被炽热碳和CO还原的综合结果，助剂有助于燃烧中CO的形成并可促进炽热碳和CO还原NOx，从而降低烟气中NOx含量。通过量子化学计算对燃烧过程中N2和NOx的生成路径分析，得到燃烧过程中N2生成主要来源于NOx的异相还原。一步引入金属复合物助剂，热解过程中可催化更多含氮化合物向气相氮转移，并生成更多N2，达到热解减氮；在焦炭燃烧时，催化剂自身的还原性以及对C及CO的催化作用有助于NOx还原成N2，达到燃烧脱硝，实现了煤热解-燃烧NOx两步控制耦合作用，降低NOx排放。.科学意义：煤基固体洁净燃料中金属复合物对热解-燃烧中氮化物污染物两步控制耦合作用机理，为低阶煤高效洁净转化利用提供理论依据，为煤炭利用环境保护理论研究作出贡献，为非均相催化理论研究提供一定支撑。