天然气再燃对炉内燃烧及流动影响的数值模拟

Numerical Simulation of the Effect of Natural Gas Reburning on In-furnace Combustion and Flow Characteristics

以1台220 t/h四角切圆煤粉炉为研究对象,采用CFD计算软件Fluent6.2对天然气再燃系统的喷射方式进行了数值模拟.研究了再燃气体及燃尽风采用切向喷射和前后墙对冲喷射对炉内NOx和CO浓度分布、温度分布以及气流旋流数的影响.结果表明:再燃气体及燃尽风的喷射方式对炉内CO浓度分布和温度分布的影响不大,但再燃气体及燃尽风采用对冲喷射时,降低NOx排放的效果好于切向喷射,并有利于减小炉膛出口气流的旋流数.

Taking a 220 t/h tangential firing pulverized coal boiler as the object of study,numerical simulation was performed on injection methods of its natural gas reburning system using CFD software Fluent6.2,（so as） to study the effects of both the tangential and opposite injection way of reburning gas and overfire air on the in-furnace NO_x and CO concentration,temperature distribution as well as air swirl number etc.Results show that on the in-furnace CO concentration and temperature distribution,the two injection ways of reburning gas and overfire air have basically the same effects,but on the reduction of both the NO_x emission and outlet air swirl number,the opposite way is better than the tangential one.