煤燃烧产生大量氮氧化物(NOx)对生态环境破坏严重，而民用散煤燃烧排放的NOx是燃煤发电排放的一倍。因此，研究民用散烧NOx排放控制意义重大。基于此，提出对原煤经干馏制备民用洁净燃料，借助“热解减氮+燃烧脱硝”2步耦合机制，实现洁净燃料直燃过程NOx的超低排放。具体研究内容:在管式炉中将煤与金属助剂(FeCl3)先经热解制备洁净燃料，再考察洁净燃料燃烧实验过程NOx排放情况。系统研究铁负载比、热解温度、燃烧温度等因素对氮在“热解-燃烧”过程的迁移规律，并对铁助剂的作用机理进行探讨。结果表明:铁助剂的负载比为0.5%，热解温度为1 000 ℃时氮脱除效果最佳，氮脱除率为93.6%。高温热解后的焦炭中铁主要以Fe2O3，Fe3O4，α-Fe形态存在，这些铁物相能够催化更多的含氮化合物转化为无污染的N2;同时，温度的升高也有利于洁净燃料燃烧过程NOx的脱除，在燃烧温度为1 000 ℃时，助剂负载比为0.5%时，NOx排放的质量浓度为116.68 mg/cm3，相比原煤燃烧NOx排放减少了46.7%。燃烧过程形成的Fe2O3对NOx与CO，C的还原反应有一定的催化作用，可以催化燃烧过程形成的NO转化为N2。铁助剂的进一步引入，借助“热解减氮-燃烧脱硝”的机制，实现了洁净燃料燃烧NOx超低排放的效果。

The nitrogen oxide (NOx) emitted from coal combustion causes serious pollution to the ecological en-vironment,and the direct combustion of household coal accounts for more than 50% of the total emission of coal pollutants.Based on this,it was proposed to achieve the ultra-low emission of NOx through two-step coupling of “pyrolysis nitrogen reduction+combustion denitrification”.The pyrolysis and combustion experiments of coal and metal auxiliary (FeCl3) were carried out in a tubular furnace,and the migration rules of nitrogen in the “pyrolysis and combustion” process were systematically studied by such factors as iron load,pyrolysis temperature and combustion temperature,and the action mechanism of iron auxiliary was discussed.The results showed that when the load ratio of iron additives is 0.5% and the pyrolysis temperature is 1 000 ℃,the nitrogen removal effect is the best,the nitrogen removal rate increases from 66.6% to 93.6%.After high temperature pyrolysis,the iron in coke mainly exists in the forms of Fe2O3,Fe3O4 and α-Fe,these iron phases can catalyze the conversion of more nitrogen-containing compounds into pollution-free N2.At the same time,the increase in temperature is also conducive to the removal of NOx in the combustion process of clean fuel.When the combustion temperature is 1 000 ℃ and the additive load is 0.5%,NOx emission is 116.68 mg/cm3,which is 46.7% less than the NOx emission from raw coal combustion.High temperature is conducive to NOx removal.When the combustion tem-perature is 1 100 ℃,NOx emissions are reduced by 46.7%.Fe2O3 formed in the combustion process has a certain catalytic effect on the reduction reaction of NOx,CO and C,and can catalyze the conversion of NO formed in the combustion process into N2.By adding iron additives in one step,the effects of reducing nitrogen and burning denitrification in two steps were achieved.

1 实验材料和方法

   1.1 材料

   1.2 实验过程

   1.3 焦炭氮和挥发性氮分析

   1.4 样品分析表征

2 实验结果与讨论

   2.1 铁助剂对煤热解减氮的影响

   2.2 铁对焦炭燃烧过程脱硝性能的影响

   2.3 铁对煤热解及燃烧中氮平衡的影响及机理

3 结论