| As China’s emission limitation of air pollutants for thermal power plants became increasingly grim, many coal-fired power plants upgrade their environmental protection equipment, even several have finished ultra-low emission reconstruction. But it lacks of theoretical study about how to apply cost-benefit appraisal analysis to environmental protection equipment and the ultra-low pollutants emission technology innovation for coal-fired flue gas.Based on domestic and foreign research methodology, this paper has established a cost-benefit calculation model, which considered several influence factors such as pollutant entrance concerntartion, unit capacity, generation load, for environmental protection installations for coal-fired power plants. Using performance curve of material balance, the operation cost of environmental protection equipment in coal-fired power plant is analyzed. The model of emission reduction benefit evaluation was based on the dose response relationship. And it was used to evaluate the health benefits and agricultural benefits On the basis of established coal-fired power plant environmental protection equipment cost benefit evaluation model, the key influence factor analysis model was built for more in-depth analysis and evaluation.Based on the model, the cost analysis about units with different capacities for limestone gypsum desulfurization equipment (WFGD), SCR denitrification installation (SCR) and electrostatic precipitator (ESP/ESP+WESP) to achieve different emission limits was accomplished under the typical scenario, under which the entrance concerntration of SO2, NOx and PM varied from 1900mg/Nm3 to 2100mg/Nm3,200 mg/Nm3 to 250 mg/Nm3 and 23g/m3 to 25g/m3, respectively. The result shown that, operation cost for WFGD, SCR and ESP/ESP+WESP was 0.0086～0.0321 yuan/kWh, 0.0043～0.0205 yuan/kWh and 0.0017～0.0106 yuan/kWh, respectively. And it increased with the rise of unit capacity and decreased with the rise of emission limitation. On the side of pollutant reduction benefits, when the pollutant emission was reducted from current situation to key-region emission limitation, the removal benefit for unit SO2, NOx and particles in Beijing, Tianjin and Hebei was 8900 yuan/ton,8892 yuan/ton and 12702 yuan/ton, respectively. Besides, the total pollutant removal benefit was 20.05 billion yuan/year, of which the economic benefit of the power station itself was 8.59 billion yuan/year, and the environmental benefits was 11.46 billion yuan/year.In addition, based on the key influencing factor analysis model, the law about how the operation cost of environmental protection equipment in coal-fired power plants varied was analyzed. The results shown that when the entrance concentration of WFGD, SCR and ESP/ESP+WESP varied from 800mg/Nm3 to 10000/m3,200 mg/Nm3 to 1000 mg/m3 and 15g/m3 to 40g/m3, respectively, the operating cost compensation of WFGD, SCR and ESP/ESP+WESP was within the scope of -24.3% to +145.4%,-18.7%至+31.0% and -22.6% to +42.8% comparing with it under the typical scenario. When the unit load varied between 40% and 100%, the operating cost compensation of WFGD, SCR and ESP/ESP+WESP was within the scope of +26.5% -21.3%,+54.0% to -31.8% and +37.1% to -29.6% comparing with it under the typical scenario, respectively.Futhermore, based on the statistics and study of the factors about unit capcity, entrance concentration of environmental equipment, the average generatiom load in Beijing, Tianjin and Hebei, the analysis about cost-benefit in different emission limitation was accomplished. When the outlet concentration of SO2, NOx and particles reached special emission limits and ultra low emission limits, the total operating cost was 6.827 billion yuan/year and 9.925 billion yuan/year, respectively. According to the analysis of emission reduction benefits, the ratio between the benefit and the cost was 2.94 when the outlet concentration of SO2, NOx and particles reached special emission limits. Besides, when it reached ultra low emission limits, the emission reduction benefit would increase by 3.55 billion yuan/year, the net profit would increase by 0.46 billion yuan/year.Finally, based on cost-benefit analysis, considering the influence of load, sulfur content and annual generating hours to pollutants removal rate, a model was constructed to evaluate the economic performance of a 1000MW coal-fired ultra-low pollutants emission power plant whose pollutant control facilities have been just upgraded. The results show that pollutants (SO2, NOx and PM) removal electricity price increased about 0.0112-0.0187yuan/kWh, accounting for about2.68%-4.47% of electricity prices. After technical reconstruction, the environmental benefit was obviously improved, since the pollutant emission for generation of SO2, NOx and PM is 0.048 g/kWh,0.109 g/kWh and 0.007 g/kWh respectively. And the environment benefit is 1.344 million yuan per year. Besides, when the operating load of the unit is raised from 60.4% to 100%,30.5%,32.1% and 38.1% operating cost would be cut in WFGD, SCR and ESP+WESP, respectively. |
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