低温省煤器飞灰沉积阻塞机理分析及结构优化  

Analysis of fly ash deposition blockage mechanism and structure optimization of low temperature economizer

作　　者：付双成[1,2] 曹港 陈强飞 孙肖润 偶国富 周发戚 李芦雨 FU Shuangcheng;CAO Gang;CHEN Qiangfei;SUN Xiaorun;OU Guofu;ZHOU Faqi;LI Luyu(School of Mechanical Engineering and Rail Transit,Changzhou University,Changzhou 213164,Jiangsu,China;Key Laboratory of Green Process Equipment in Jiangsu Province,Changzhou 213164,Jiangsu,China;Sinopec Yangzi Petrochemical Branch Thermal Power Plant,Nanjing 210018,Jiangsu,China)

机构地区：[1]常州大学机械与轨道交通学院,江苏常州213164 [2]江苏省绿色过程装备重点实验室,江苏常州213164 [3]中国石化扬子石化分公司热电厂,江苏南京210018

出　　处：《化工进展》2022年第8期4035-4046,共12页Chemical Industry and Engineering Progress

基　　金：江苏省研究生科研创新计划(KYCX21_2811);中石化技术开发项目(10750000-21-ZC0607-0001)。

摘　　要：针对热电厂低温省煤器发生飞灰沉积阻塞炉管间隙的情况,本文采用剪切力传递(SST)k-ω湍流模型和离散粒子模型(DPM)分析飞灰颗粒沉积行为,预测省煤器中支撑梁附近的沉积动态,进而对支撑梁上方翅片布置结构进行优化和流场分析。结果表明:省煤器中由于支撑梁和上方翅片的存在,飞灰颗粒会在支撑梁上表面进行沉积。在脱硝条件下,硫酸氢铵增加了飞灰间的黏结力,加剧了黏附沉积,进而积灰不断地向上累积增长并造成堵塞。通过改变支撑梁上方的翅片布置结构,可改变支撑板附近的烟气流动规律。对于烟气中的绝大部分飞灰颗粒(d>40μm),其所受到的惯性作用占据主导地位,与壁面有着较大的撞击率。通过改变炉管上翅片的布置方式,增加飞灰颗粒横向移动的能力,对支撑梁上的沉积堵塞有着较好的改善作用。In response to the occurrence of fly ash deposition blocking the furnace tube gap in low-temperature economizer of thermal power plants,the particle deposition behavior was analyzed using a shear transfer(SST)k-ωturbulence model and a discrete particle model(DPM).The deposition dynamics near the support beam in the economizer was predicted,and then the fin arrangement structure above the support beam was optimized and flow field was analyzed.The results showed that fly ash particles were deposited on the upper surface of the support beam due to the presence of the support beam and the upper fins in the coal economizer.Under denitrification conditions,ammonium bisulfate increased the adhesion between the fly ash.This aggravated the adhesion deposition,and thus the ash accumulation grew upwards and caused blockage.By changing the structure of the fin arrangement above the support beam,the flue gas flow pattern near the support plate was changed.For most of the fly ash particles(d>40μm)in the flue gas,the inertial effect dominated and had a large impact rate with the wall.By changing the arrangement of the fins on the furnace tube,the ability of the fly ash particles to move laterally was increased,which has a better effect on the deposition blockage on the support beam.

关 键 词：省煤器 飞灰颗粒 沉积物 热传导 数值模拟 

分 类 号：TK172[动力工程及工程热物理—热能工程]