干煤粉气流床气化炉氮污染物生成模拟

Simulation analysis on nitrogen pollutants formation in combustion area of entrained-flow pulverized coal gasifier

将煤粉折算后,应用K intecus软件对煤粉气流床反应过程进行了模拟,考察了输送气体、氧煤比和汽煤比对煤粉气流床气化炉含氮物生成及转化的影响。结果显示,以N2作为输送介质会影响含氮污染物的生成量,但煤中的N仍是氮污染物的主要来源。氧气量的增加会使大量的HCN及少量的N2被消耗并使NO的生成量增加,而部分氮氢基(NHi)也会被氧化。当汽煤比较低时,水蒸气在高温及氧的作用下会生成大量的OH基,此基团会氧化HCN、NHi和N2而使其生成量减少;当汽煤比较高时,温度的降低及OH基的减少使较少的HCN和NHi被氧化和分解,同时更多的H2与N2反应而生成NHi。

The component of pulverized coal was converted and the reaction process of entrained-flow pulverized coal gasifier was simulated by using Kintecus software. The effects of carrier gas, O2/coal ratio and H2O/coal ratio on the formation and conversion of nitrogen pollutants were investigated. The results show that if use Nz as the carrier gas, it will affect nitrogen pollutants formation, but the nitrogen in coal is the main source of the nitrogen pollutants. As oxygen increases, a great deal of HCN and a little portion of N2 can be consumed and the formation of NO increases, a portion of NHi is also oxidized. On the low H2O/coal ratio, H2O decomposes to OH radicals under the effect of high temperature and oxygen,which lead to the decrease of HCN,NHi and N2 through the oxidation reactions. On the high H2O/coal ratio,less HCN and NHi are oxidized and decomposed for the decrease of temperature and OH radicals, and more NHi forms through the reaction between H2 and Ni.