【作者】 王庆；

【导师】 谢克昌； 冯杰；

【作者基本信息】 太原理工大学 ， 化学工艺， 2004， 硕士

【摘要】 本文以化学渗透脱挥发分模型（CPD）为基础构建煤的结构，以实验数据为基础，通过对煤中氮在热解阶段反应历程的描述与分析，假设两种NO_x主要前驱体HCN和NH₃的释放机理，并对其进行动力学表达，建立了快速煤热解氮释放的模型。通过对HCN和NH₃模拟结果和实验结果的比较，探讨热解阶段HCN和NH₃的生成机理和释放规律。假设的两种机理分别为： 机理一：热解过程中焦油内含氮杂环通过H自由基活化而裂解形成HCN和NH₃，HCN和NH₃的产量由其本身的H含量确定；焦中释放的氮全部转化为NH₃。 机理二：焦中释放的氮转化为NH3；以焦油碎片的稳定性确定焦油中释放的HCN和NH₃的量，轻质焦油（分子量＜400amu）释放的氮转化为HCN，重质焦油（分子量≥400amu）释放的氮转化为NH₃。 通过研究获得以下结论： （1） 两种机理都假定HCN的形成发生于焦油二次反应过程中，且能比较正确的表达HCN的释放，表明HCN是二次热解过程中焦油含氮杂环断裂的产物。机理一说明在HCN的形成过程中，H自由基起重要的作用。机理二则进一步表明HCN由轻质焦油碎片中的含氮杂环断裂形太原理工大学硕士研究生毕业论文成。 （2）两种假设机理都没有正确表达出NH3的形成。可能的原因是:模型中对氮转化为NH3历程的描述和表达同实际情况有偏差:也可能是模型中对影响NH3释放的因素考虑不完全，还有其他重要因素影响NH3的形成。 （3）不同煤阶的煤NH3的释放没有明显规律，相同煤阶的煤形成的NH3也有很大的差异，说明煤阶对NH3的形成不起决定作用，由于煤阶和挥发分密切相关，即挥发分也不起决定作用，进一步说明了 NH3不完全形成于挥发物质中。 （4）HCN的形成同挥发分有关，挥发分越高，释放出的HCN越多。 （5）HcN和NH3的生成量是温度的函数，随着温度的升高，形成HCN和NH3的量都增加;更多还原

【Abstract】 Due to the complexity of nitrogen released reaction in coal and the lack of effective experimental methods, there is less sound understanding for the formation and release of precursors of NOx, which are HCN and NH3, during coal pyrolysis. In this paper, a mathematic model that describes the reaction route and mechanism of nitrogen and predicts the formation of HCN and NH3 by kinetics during coal pyrolysis has been developed based on the CPD model. By comparing simulation of HCN and NH3 values with experimental data, the nitrogen release rule during coal pyrolysis is discussed.The conclusions are as following:The successful predict of HCN formation indicates that HCN result from the thermal cracking of N-containing heteroaromatic ring during second pyrolysis of tar, and H radicals take a important part in HCN formation.The disagree simulation of NH3 formation show that the reaction route of nitrogen described in the model is different from the actual ,or the factor influencing NH3 formation are not enough to describe NH3 release in the model.The yield of NH3 vary irregularly with coal rank, the coals withsimilar rank release diferrent yield of NH3, which indicate coal rank that has a strong relation with the amount of volatiles in coal is not the decisive factor influencing NH3 formation, and proves that not all of NH3 come from volatile matters.With the the amount of volatiles increasing ,the yield of HCN increases.The yields of HCN and NH3 increase with increasing temperature.更多还原