燃煤机组协同处置可燃一般固废气化气的影响分析及改造方案设计

INFLUENCE ANALYSIS OF COAL-FIRED UNIT CO-PROCESSING COMBUSTIBLE GENERAL SOLID WASTE GAS GASIFICATION AND DESIGN OF RENOVATION PLAN

为研究可燃一般工业固废气化气掺烧对燃煤机组的影响,对掺烧定量的可燃一般固废气化气进行了锅炉热力系统建模计算。结果表明:在262.5,175,88 MW负荷时炉效分别降低0.44%、0.89%和0.98%,负荷越低,锅炉效率下降绝对值越大。如果利用汽轮机凝结水回收气化气余热,通过EBSILON软件搭建汽轮机热力系统模型进行计算,在抽取凝结水参与气化气换热后,能够通过回收的热量抵消炉效下降带来的煤耗增大,在中高负荷煤耗反而下降,但是在50%负荷以下,炉效影响大于回收热量的影响,煤耗会小幅增大。此外,掺烧少量一般固废气化气后对机组的受热面高温腐蚀、重金属、SO_(2)、NO_(x)等污染物排放等均不会有较大不利影响,但仍需对一般固废气化原料中的Cl、Na等元素进行控制。对生物质气化气入炉方案进行数值模拟计算,2种掺烧方案对比得出,在前后墙加装4只燃气燃烧器对炉膛燃烧不会造成影响,推荐采用在原锅炉上层燃烧器加装燃气燃烧器,对锅炉炉膛燃烧组织和NO_(x)脱除均有利。

In order to study the influence of combustible general industrial solid waste gas blending on coal-fired units,The boiler thermodynamic system modeling and calculation are carried out for mixing quantitative combustible general solid waste gasification gas.The research shows that the boiler efficiency decreases by 0.44%,0.89%and 0.98%respectively at the loads of 262.5 MW,175 MW and 88 MW.The lower the load,the greater the absolute value of the decrease in boiler efficiency.The calculation shows that after the condensate water is extracted to participate in the heat exchange of the gasification gas,the recovered heat can offset the increase in coal consumption caused by the decrease in furnace efficiency.However,below 50%load,the effect of furnace efficiency is greater than the effect of recovered heat,and coal consumption will increase slightly.In addition,the study found that the burning of a small amount of general solid waste gasification gas will not have a great adverse effect on the high temperature corrosion of the heating surface,heavy metals,SO_(2),NO_(x)and other pollutant emissions,but the elements such as Cl and Na in general solid waste gasification raw materials still need to be controlled.Numerical simulation calculation is carried out for the biomass gasification gas feeding scheme,and the two mixed combustion schemes are compared.It can be concluded that installing 4 gas burners on the front and rear walls will not affect the combustion of the furnace,and it is recommended to use the upper layer of the original boiler to burn.The addition of a gas burner to the boiler is beneficial to both the combustion of the boiler furnace and the removal of NO_(x).