煤粉工业锅炉NO_(x)生成特性数值模拟研究--燃烧器内二次风开度影响  

Numerical study on the influence of the internal secondary air opening of the burner on the NO_(x) generation characteristics of the pulverized coal industrial boiler

作　　者：杨秀超 马俊方 王彦文 秦煌 刘建国[1] 姜秀民[1] 刘加勋[1] YANG Xiuchao;MA Junfang;WANG Yanwen

机构地区：[1]上海交通大学机械与动力工程学院,上海200240

出　　处：《电力科技与环保》2021年第6期1-7,共7页Electric Power Technology and Environmental Protection

基　　金：国家自然科学基金项目(51776123,52076133)。

摘　　要：为提高煤粉工业锅炉燃烧效率,研究NO_(x)生成特性,从燃烧系统的角度出发,通过CFD数值模拟的方法,研究了不同内二次风开度下炉内流动、燃烧及NO_(x)生成特性。结果表明:各工况下,在燃烧器出口区域均形成了稳定的旋流回流区。烟气在高温旋涡燃尽装置中一部分贴着上壁面流向出口,另一部分则在下壁面形成一个低速烟气回流区,总体上在炉内形成对称稳定的“灯芯”形火焰。当内二次风开度为0%和30%时,炉膛内温度分布均匀,火焰充满度较好;而当内二次风开度为50%时,炉膛内火焰沿着燃烧器上下两侧逐渐分散。此外,在燃烧器中心的旋流回流区边界上NO_(x)浓度较高;反之,在旋流回流区内NO_(x)浓度较低。当内二次风开度为0%时,炉膛出口NO_(x)原始排放浓度最低,可达90.08 mg/m^(3),且炉膛整体燃尽效果也最好。本研究可以为燃煤超低NO_(x)排放工业锅炉的设计与运行提供参考。In order to improve the combustion efficiency of pulverized coal industrial boilers and study the generation characteristics of NO_(x),from the perspective of combustion system,through the CFD numerical simulation,the flow,combustion and NO_(x) generation characteristics in the furnace under different internal secondary air openings are studied.The results show that under all working conditions,a stable swirling flow recirculation zone is established in the exit area of the burner.In the high-temperature vortex burn-out device,a part of the flue gas flows to the outlet along the upper wall side,and the other part forms a low-speed flue gas recirculation zone on the lower wall side.As a whole,an asymmetrical and stable"wick"flame is formed in the furnace.When the internal secondary air opening is 0%and 30%,seprately,the temperature distribution in the furnace is even,and the fullness degree of flame in the furnace is full.While the opening is 50%,the flame gradually disperses to the upper and lower sides of the burner.Moreover,the NO_(x) concentration is higher at the boundary of the swirling flow recirculation zone.On the contrary,the NO_(x) concentration is lower in the center of the swirling flow recirculation zone.When the internal secondary air opening is 0%,the NO_(x) emission at the furnace outlet is the lowest,which is 90.08 mg/m^(3),and the overall burn-out effect of the furnace is also the best.This research can provide a reference for the design and operation of pulverized coal ultra-low NO_(x) emission industrial boilers.

关 键 词：工业锅炉 燃尽装置 旋流回流区 内二次风开度 燃烧特性 NO_(x)生成特性 数值模拟 

分 类 号：TK223.2[动力工程及工程热物理—动力机械及工程]