对二甲苯联合装置二甲苯加热炉综合改造分析

某公司600 kt/a对二甲苯联合装置二甲苯加热炉存在火嘴燃烧效果差、排烟温度偏高、炉膛过剩氧含量偏高、炉膛外壁散热损失大等问题,针对上述问题对装置进行了综合性改造。通过采取更换新型高效低氮燃烧器及高效板式预热器、增设CO分析仪、进行炉壁隔热喷涂和更换保温材料等措施,使得火嘴燃烧状况得到显著改善,二甲苯加热炉环保排放指标达到要求,排烟氮氧化物的质量浓度由178 mg/m^3降低到35 mg/m^3,排烟温度由145℃降低到110℃,烟气过剩氧体积分数由2.3%降低到0.9%,加热炉外壁温度下降20℃以上。通过改造,装置的加热炉效率得到了提高,二甲苯加热炉效率(炉效)由改造前的91.6%上升至93.5%,达到了节能环保的目的。

Analysis on comprehensive revamping of xylene heating furnace in a P-xylene unit

The P-xylene furnace in a 600,000 TPY P-xylene unit of a company suffered from poor combustion performance,higher flue gas emission temperature,higher excessive oxygen in combustion chamber,higher heat loss of external shell of the furnace,etc.To solve these problems,the unit has been revamped.After taking the following measures such as replacement with new high-efficiency low-nitrogen combustor and high-efficiency plate preheater,installation of CO analyzer,and application of heat insulation coatings,linings and bricks,etc,the combustion of fire nozzles has been obviously improved.The emissions of P-xylene furnace have met the standard emission specifications for environmental protection.The nitrogen oxides in flue gas is reduced from 178 mg/m^3 to 35 mg/m^3,the exhaust temperature is lowered from 145℃to 110℃,the excessive oxygen content in flue gas is reduced from 2.2%to 0.9%,and the furnace wall temperature is lowered by more than 20℃.After revamping,the thermal efficiency of the furnace has been improved,the thermal efficiency of P-xylene furnace is raised to 93.5%from 91.6%,and a good contribution has been made to environmental protection.