不同富氧条件下高炉煤气和焦炉煤气燃烧数值模拟  

Numerical Simulation of Blast Furnace Gas and Coke Oven Gas Combustion under Different Oxygen Enrichment Conditions

作　　者：易正明[1,2] 张丑 周正 林超群 YI Zheng-ming;ZHANG Chou;ZHOU Zheng;LIN Chao-qun(State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan,China,Post Code:430081;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan,China,Post Code:430081)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《热能动力工程》2022年第2期84-91,共8页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金(51604199)。

摘　　要：为研究高炉煤气和焦炉煤气在不同富氧条件下的燃烧特性,以某钢厂75 t/h燃气锅炉为对象,利用数值模拟软件Fluent,选用带旋流修正的Realizable k-ε湍流模型和有限速率/涡耗的散燃烧模型,采用速度入口、压力出口、标准壁面方程、无滑移、无湍流运动边界条件,对炉内着火距离、温度和热流密度分布进行了模拟。结果表明:焦炉煤气着火距离比高炉煤气短,焦炉煤气在富氧31%工况较空气燃烧工况更早达到1000 K的稳定燃烧温度;燃气锅炉富氧后整体温度降低,温度分布更加均匀,空气燃烧、富氧26%和富氧31%三种工况的最高温度分别为1867,1678和1834 K;高炉煤气和焦炉煤气在O_(2)/CO_(2)燃烧条件下,气体辐射换热性能得到增强,炉内整体热流密度提升明显,富氧工况下整体温度较空气燃烧工况低,但壁面热流增大;富氧后炉膛内NO_(x)的生成量降低,富氧26%工况下折焰角处折算至3%O_(2)的NO生成由空气燃烧工况的8.12 mg/m^(3)降至0.63 mg/m^(3)。In order to study the combustion characteristics of blast furnace gas(BFG)and coke oven gas(COG)under different oxygen-enriched conditions,a 75 t/h gas-fired boiler in a certain steel mill was taken as the object,the numerical simulation software Fluent was used to select the realizable k-εturbulence model with cyclone modification and the diffusive combustion model with finite rate and vortex dissipation.Using velocity inlet,pressure outlet and standard wall equations,under the boundary conditions of no slip or turbulent motion,the ignition distance,temperature field and heat flux density distribution in furnace were simulated.The results show that the ignition distance of coke oven gas is shorter than that of blast furnace gas,and coke oven gas reaches the stable combustion temperature of 1000 K earlier under the condition of 31%oxygen enrichment than under the air combustion condition.After oxygen enrichment,the overall temperature in the gas-fired boiler decreases and the temperature distribution is more uniform.The maximum temperatures of air combustion,26%oxygen enrichment and 31%oxygen enrichment are 1867 K,1678 K and 1834 K respectively.Under the conditions of O_(2) and CO_(2) combustion,the radiation heat transfer performance of mixed gas is enhanced,and the heat flux density in the furnace is improved obviously,which leads to the wall surface heat flux increased even though the overall temperature under the oxygen enrichment condition is lower than that under the air combustion condition.The NO_(x) production in the furnace decreases after oxygen enrichment,and the NO density converted to 3% O_(2) at the furnace arch decreases from 8.12 mg/m^(3) under the air combustion condition to 0.63 mg/m^(3) under the condition of 26%oxygen enrichment.

关 键 词：富氧燃烧 燃气锅炉 碳捕捉 氮氧化物 数值模拟 

分 类 号：TK16[动力工程及工程热物理—热能工程]