氧分级对药渣O2/CO2燃烧NOx生成规律与反应机理的影响

在我国目前能源结构中,化石能源尤其是煤炭资源占比很高,造成了极大的环境压力。抗生素发酵药渣为近年来产量迅速升高的固体废弃物,也是一种生物质燃料资源,但目前对药渣的能源化利用研究较少。以CH4等气体来模拟药渣可燃成分,利用Chemkin模拟软件中的PFR反应器构建了药渣在O₂/CO₂气氛下氧气分级燃烧及非分级燃烧模型,对2种情况下NO_x生成特性进行了模拟研究,探求了氧气分级及非分级燃烧时各种因素的影响,并利用生成速率分析法和敏感性分析法对结果进行了反应机理分析。研究结果表明,在氧气非分级条件下,NO_x转化率随燃烧温度升高先升高后降低,在1500℃左右达到峰值;NO_x转化率随过量氧气系数增加而升高,在过量氧气系数由0.9增至1.1时,增幅显著。在氧气分级条件下,主燃区燃烧温度对NO_x转化率的影响较为复杂;NO_x转化率随燃尽风率增加先降低后升高,随燃尽风位置推后降低。氧气分级条件下,还原气氛促进了NO_x中N向其他组分转化,能够明显降低NO_x生成。当燃烧温度低于1500℃,燃尽风率为0.35左右时,NO_x转化率最低。首次对药渣在O₂/CO₂气氛下的燃烧进行了反应动力学模拟研究,探求了各种因素的影响,为实现药渣能源化利用提供了指导。

Influences of oxygen staging on NOx production and reaction mechanism during O2/CO2 combustion of antibiotic filter residue

In China′s current energy structure,the proportion of fossil energy,especially coal resources,is relatively high,which causes great environmental pressure.As a solid waste with rapidly increasing yield in recent years,antibiotic filter residue is also a kind of biomass fuel resource,but research on the energy utilization of residue is insufficient at present.In this paper,CH4 and other gases were used to simulate the combustible components of the residue,and the PFR reactor in Chemkin software was used to construct the model of oxygen staged combustion and unstaged combustion of residue in O₂/CO₂ atmosphere.NO_x production characteristics under the two condi?tions were simulated to study the influences of various factors in oxygen staged combustion and unstaged combustion,and the reac?tion mechanism of the results were analyzed by production rate analysis and sensitivity analysis.The results show that under the oxygen un?staged combustion,the conversion rate of NO_x first increases and then decreases with the increase of combustion temperature,reaching the peak at about 1500℃;the conversion rate of NO_x increases with the increase of excess air coefficient,and increases significantly when the excess oxygen coefficient increases from 0.9 to 1.1.Under the oxygen staged combustion,the combustion temperature of primary combustion area has a complicated effect on the conversion rate of NO_x;the conversion rate of NO_x first decreases and then increases with the increase of rate of overfire air;the conversion rate of NO_x decreases as the position of over fire air is pushed back.Under the oxygen staged combus?tion,the reducing atmosphere promotes the transformation of N in NO_x to other components,which can significantly reduce the NO_x produc?tion.The NO_x conversion rate is the lowest when the combustion temperature is lower than 1500℃and the rate of overfire air is about 0.35.In this paper,the reaction kinetics simulation study of the combustion of antibiotic filter residue in O₂/CO₂ atmosphere is carried out for the first time,and the influences of various factors is explored,which has a guiding significance for the energy utilization of residue.