近10a,国内学者和工程技术人员进行了大量燃煤耦合污泥发电技术相关的学术研究和工程应用,然而大部分研究和应用均在机组70%负荷以上开展,鲜见燃煤耦合污泥发电在碳减排效果方面的相关研究。为掌握燃煤耦合污泥发电技术在机组中低负荷工况下对锅炉的全方位影响规律,在某700MW四角切圆粉煤锅炉上开展了50%负荷下燃煤耦合生活污泥发电现场工程试验,系统研究了燃煤耦合污泥发电对锅炉热效率、污染物排放、二噁英排放、副产物重金属含量、CO2排放的影响。结果表明:在50%额定负荷下,与不掺烧污泥相比,掺烧3%的污泥使锅炉热效率下降了0.52%,掺烧6%的污泥使锅炉热效率下降1.03%;随污泥掺比上升,炉渣含碳量相应升高,直接导致物理不完全燃烧热损失增加;掺烧污泥对燃煤电厂锅炉粉尘、SO2、NOx等常规污染物排放无明显影响,电厂机组环保设施的处理能力可完全保证掺烧污泥时常规污染物符合超低排放标准;掺烧污泥比例越大,烟气净化装置对二噁英的脱除率相应升高,所有工况的二噁英毒性当量均低于DB31/1291—2021《燃煤耦合污泥电厂大气污染物排放标准》规定的0.01ng/m3;粉煤灰中的Cr、Cu、Zn,炉渣中的Cr、As、Ba、Ni、Zn,脱硫石膏中Cu对污泥掺烧比例相对敏感,考虑副产物用于土壤改良的情况下,掺烧污泥工况的电厂副产物重金属含量仍符合相关农业标准;通过理论计算,掺烧3%污泥约多排放0.15%的CO2,掺烧6%污泥约多排放0.3%的CO2,耦合污泥发电技术的应用需在污泥类型、污泥前处理、掺烧负荷、燃烧调整等多方面进行优化,方可实现减污降碳协同增效。

In the past 10 years, domestic scholars and engineers have carried out a large number of academic research and engineering applications related to coal -fired coupled sludge power generation technology, but most of the research and application are carried outat more than 70% load of the unit, and there are few rele-vant studies on the carbon emission reduction effect of coal-fired coupled sludgepower generation. In order to understand the full range of effects of coal-fired coupled sludge power generation technology on boilers under medium and low load conditions, field engineering tests of coal -fired coupled domestic sludge power generation under 50% loadwere carried out on a 700 MW quadrangle tangential pulverized coal boiler. The effects of coal-fired coupled sludge power generation onboiler thermal efficiency, pollutant emission, dioxin emission, heavy metal content of by-product and CO2 emission were systematicallystudied. The results show that under 50% rated load, the boiler thermal efficiency decreases by 0.52% with 3% sludge and 1.03% with6% sludge, compared with that without sludge. With the increase of sludge ratio, the carbon content of slag also increases correspondingly, which directly leads to the increase of heat loss in physical incomplete combustion. The incineration sludge has no significant effect onthe discharge of dust, SO2, NOx and other conventional pollutants in coal-fired power plants, and the treatment capacity of the environmental protection facilities of the power plant units can fully ensure that the regulated pollutant discharge during the incineration sludge isin line with ultra-low emission standards. The higher the proportion of mixed sludge, the higher the removal rate of dioxins in flue gas purification plant, and the dioxins toxicity equivalent of all operating conditions are lower than 0.01 ng/ m3 stipulated in DB 31/ 1291—2021" Emission Standard of Air Pollutants in coal-fired coupled Sludge Power Plant" . Cr, Cu, Zn in fly ash, Cr, As, Ba, Ni, Zn in slag,and Cu in desulfurized gypsum are relatively sensitive to sludge blending ratio. Considering the use of by-products for soil improvement,the heavy metal content of by-products in power plant under sludge blending condition still meets relevant agricultural standards. According to theoretical calculation, 3% sludge will emit 0.15% more CO2, 6% sludge will emit 0.3% more CO2, the application of coupledsludge power generation technology needs to be optimized in sludge type, sludge pretreatment, combustion load, combustion adjustmentand other aspects, in order to achieve the synergistic effect of pollution reduction and carbon reduction.

0 引言

1 机组概况与试验设计

   1.1 700 MW亚临界燃煤机组概况

   1.2 试验工程设计

   1.3 试验方法

2 试验结果及分析

   2.1 燃料成分分析

   2.2 掺烧污泥对锅炉热效率的影响

   2.3 掺烧污泥对烟气常规污染物排放的影响

   2.4 掺烧污泥对二噁英排放的影响

   2.5 掺烧污泥对副产物重金属含量的影响

   2.6 掺烧污泥对CO2排放的影响

3 结论