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为研究富氧燃烧过程中的NOx生成与控制,在一维沉降炉上进行了煤的分级富氧燃烧试验,并利用Matlab和Cantera软件建立了一维沉降炉反应模型并进行分析。试验温度1 100~1 200℃,给粉量21.1~32.3 g/h。试验和模拟结果表明:富氧燃烧时不采用烟气再循环的方法时NOx生成量也可比空气下燃烧时低。在未分级条件下,富氧燃烧时的NOx排放量是空气工况的77%。通过推迟二次风后移、缩小一次风风率等手段延长一次风在还原区的停留时间,可降低富氧燃烧时的NOx生成量。高浓度CO2和焦炭的气化反应有助于强化还原区的还原性气氛,促进NO在焦炭表面的还原,促进焦炭N向N2的转化,抑制焦炭NOx的生成。一维模型模拟结果与试验吻合。
In order to study the generation and control of NOx in oxygen-rich combustion process, the staged oxygen enrichment combustion test of coal was carried out on one-dimensional sedimentation furnace. The one-dimensional reaction model of sedimentation furnace was established by Matlab and Cantera software. Test temperature 1 100 ~ 1 200 ℃, to the amount of powder 21.1 ~ 32.3 g / h. The results of the tests and simulations show that the NOx production can be lower than that under air when oxygen-free combustion is used without recirculation of flue gas. Under unfractionated conditions, NOx emissions during oxyfuel combustion are 77% of the air operating conditions. By delaying the secondary air backward movement and reducing the primary air wind rate, the residence time of the primary air in the reduction zone can be prolonged to reduce the NOx production during oxy-combustion. The gasification reaction of high concentration of CO2 and coke helps to strengthen the reducing atmosphere in the reduction zone, promote the reduction of NO on the coke surface, promote the conversion of coke N to N2 and inhibit the formation of coke NOx. One-dimensional model simulations agree well with the experimental results.