高碱固体燃料燃烧中碱金属的迁移行为及其对于污染物生成的微观调控

There exist high content of alkali metals in solid fuels, such as Zhundong coal, biomass, and waste. And these are key elements that cause formation of pollutants and fouling, slagging, and corrosion. At present, the problems raised by alkali metals in solid fuel combustion catch extensive attentions at home and abroad. This project will be focused on investigation of transformation and microscopic modulation on pollutant formation of nano-scaled alkali metal clusters in combustion. First of all, the advanced particle surface characterization technique will be used to obtain existing structure and distribution of alkali clusters in solid fuels, and the distribution prediction model of alkali metals is established for different solid fuels. Then, we set up a pressured tubular flame bench of solid fuels and improve TDLAS in determination of concentration of gaseous alkali metals to obtain released data and dynamic model under different combustion atmosphere, temperatures, pressures, and plasma auxiliary conditions. At the same time, the influence of alkali metals on pollutants in combustion of solid fuels is also studied to analyze the mechanism of combustion pollutants and denitration. Finally, the generating mechanism of nano-scaled alkali clusters and its microscopic modulation mechanism are obtained by analyzing the key path of complex reaction of alkali metals with nitrogen, sulfur, and chlorine. The combustion of solid fuel will be simulated based on a reduced mechanism from the detailed reactions.

准东煤、生物质和废弃物等固体燃料中均存在高含量的碱金属，是影响燃烧污染物生成以及积灰、结渣、腐蚀等问题的关键元素，因此国内外十分关注这些高碱燃料燃烧中碱金属的影响问题。本项目研究高碱燃料燃烧中碱金属的迁移行为及其对于污染物生成的微观调控，首先采用颗粒表面表征技术得到燃料中纳米级碱金属团簇的存在结构及分布特性，建立不同燃料碱金属的分布特性预测模型；然后建立增压环境的固体燃料管状火焰实验台并完善气相碱金属浓度的TDLAS在线诊断系统，得到不同燃烧气氛、温度、压力以及等离子体辅助条件下的碱金属释放数据及其释放动力学模型；同时在管状火焰和携带流反应器实验台上，研究燃烧中碱金属对于污染物生成的影响，得到碱金属影响污染物生成以及脱硝效果的机制；最终，通过分析碱金属与氮、硫、氯等组分复杂反应的关键途径，获得纳米级碱金属团簇的生成机理及其微观调控机制，并实现基于详细反应简化机理的固体燃料燃烧模拟。