氧浓度对褐煤低温热解产物的影响

为研究不同氧浓度对褐煤低温热解提质产物的影响,在550℃温度下,进行了0~16%(每间隔2%)氧浓度下的固定床热解试验。结果表明,氧气的氧化供热作用促进气体和液态产物的生成;当氧浓度达到12%时,液态产物产量达到最大,当氧浓度过高时,液态产物发生二次反应的作用加剧,液态产物产量减小;氧浓度达到10%时,样品开始出现局部燃烧,氧气的消耗加剧,固体产物质量减少最快,气体产物质量增长最快,并且固定碳的减少使得提质后煤中灰分增加,导致热值下降,因此在有氧气氛下需降低提质温度及提质反应时间。研究同时表明,氧浓度的升高有助于脱除褐煤中大分子物质中的杂环氮,且在有氧气氛下低温热解可以有效脱除不饱和芳香结构物质。

Impacts of oxygen concentration on products up-grading of lignite from low-temperature pyrolysis

Pyrolysis experiment of lignite with the oxygen concentration of 0-16% (with the interval of 2%) was carried out on a fixed bed reactor under 550 ℃ to study the influence of oxygen concentration on low-temperature pyrolysis products.It was found that the oxidation heating effect of oxygen could promote the generation of gas and liquid.When the oxygen concentration reached 12%,the yield of liquid reached the maximum,and when the concentration of oxygen was too high,the effect of secondary reaction with liquid was remarkable,and the yield of liquid was decreased;while,when the oxygen concentration was 10%,the samples started to appear local combustion,the consumption of oxygen increased,the quality of solid product reduced fastest,the quality of gas product increased fastest,and the reduction of fixed carbon made the ash content of up-grading coal increase and the heat value decrease.Therefore,the up-grading temperature and reaction time should be reduced in the oxygen atmosphere.Results showed that the increase of oxygen concentration was beneficial for the removal of heterocyclic nitrogen from macromolecule in lignite,the oxygen can effectively remove unsaturated aromatic compounds.