Influence of papermaking biomass co-firing on operation energy efficiency and gas emission stability of a coal-fired thermal power plant: A case study

Biomass co-firing is an effective strategy for improving the energy structure of coal-fired power plants and coping with the pressure of carbon reduction. To ensure that the main energy supply function of the power plant is unaffected, the actual operating energy efficiency and gas emission stability after biomass co-firing need to be evaluated. Therefore, the energy efficiency and gas emission stability of an operating coal-fired power plant after co-firing with papermaking biomass (sludge, biogas, and wood chips) were analyzed. The results showed that the biomass blending ratio of 14.09 % could meet the plant energy demand and increase the annual and comprehensive thermal efficiency by 12.38 % and 9.45 %, respectively. However, the energy efficiency and gas emissions of different co-firing processes were different. When sludge, biogas, and wood chips were co-fired, the energy efficiency and gas emission reduction effect were optimal, the average monthly comprehensive thermal efficiency was increased by 8 %, and the emission intensity of CO2, SO2, NOX and PMs was reduced by 32.24 %, 57.14 %, 33.33 % and 41.33 %, respectively. In addition, the stability grade evaluation showed that after the low-carbon transition, the energy efficiency stability was improved by 1 grade, and the emission reduction stability of CO2, SO2, NOX, and PMs was improved by 1-3 grades. The research results provide an important reference for the clean and low-carbon operation transformation of actual coal-fired power plants.