京津冀地区散烧煤与电采暖大气污染物排放评估

散烧煤供暖是一种污染物排放量大、一次能源利用效率低的供暖方式,亟需寻找一种新的供暖方式替代散烧煤供暖.在对比评估散烧煤与电煤各种主要污染物排放量的基础上,提出直接电采暖和低温空气源热泵两种替代散烧煤供暖方案,以缓解京津冀地区大气污染,并对改造前后的污染物排放量和技术经济性进行分析；从区域污染物综合减排的战略角度提出对京津冀地区原散烧煤采暖用户进行低温空气源热泵供暖改造和燃煤电厂执行“超净排放”改造两种方案,并对两种方案的污染物减排效果进行了对比.结果表明:单位散烧煤的污染物排放量远高于电煤,其中散烧煤的SO₂、NO_x、烟尘和综合PM_2.5排放因子分别为17.12、2.80、6.37和9.80 g/kg,电煤的SO₂、NO_x、烟尘和综合PM_2.5排放因子分别为0.43、0.85、0.17和0.47 g/kg,散烧煤对综合PM_2.5的贡献是电煤的20.9倍；直接电采暖和低温空气源热泵供暖均能有效减少污染物排放量,其中直接电采暖可使每户每年采暖期的SO₂、NO_x、烟尘和综合PM_2.5分别减排66.38、7.15、24.79和36.96 kg,而采用低温空气源热泵的减排量分别为67.79、9.97、25.35和38.52 kg,但直接电采暖方式的一次能源利用效率(仅为33.7%)极低,因此不适合大面积推广；京津冀地区原散烧煤采暖用户在进行低温空气源热泵供暖改造后,其SO₂、NO_x、烟尘和综合PM_2.5年减排量分别为24.47×104、3.60×104、9.15×104和13.91×104 t,燃煤电厂执行“超净排放”改造后相应年减排量分别为1.28×104、4.25×104、1.30×104和2.31×104 t,其中低温空气源热泵供暖改造后的综合PM_2.5减排量达到燃煤电厂改造的6.0倍,并且年投资也较燃煤电厂改造低约4×108元.研究显示,采用低温空气源热泵供暖在污染物减排量、技术经济性和实施可行性等方面均具有优势. 

Evaluation of Air Pollutant Emissions from Scattered Coal Burning and Electric Heating in Beijing-Tianjin-Hebei Region

Scattered coal burning for heating has high pollution impacts and low energy efficiency； therefore, an improved heating pattern should be explored.Based on an evaluation of the main pollutant emissions from scattered coal burning and thermal coal, we propose a concept for mitigating pollutant emissions in the Beijing-Tianjin-Hebei region during the heating season by replacing scattered coal burning with electric heaters or low temperature air source heat pumps. The quantities of main pollutant emissions and techno-economic performance of the two options were further evaluated. Finally,for comprehensive mitigation of pollutant emissions, two alternatives were put forward and compared. One was replacing the scattered coal burning by using low temperature air source heat pumps for heating, and the other was implementing super-clean emissions in coal-fired power plants. The results showed that the pollutant emissions of scattered coal burning were greater than those of the thermal coal.SO₂, NO_x, smoke dust and integrated PM_2.5 emissions were 17.12, 2.80, 6.37 g/kg and 9.80 g/kg respectively from the scattered coal burning, and were 0.43, 0.85, 0.17 and 0.47 g/kg respectively from the thermal coal. PM_2.5 emissions from the scattered coal burning were 20.9 times higher than those of thermal coal. Both the electric heaters and heat pumps could effectively reduce the pollutant emissions. For a typical rural household, the SO₂, NO_x, smoke dust and integrated PM_2.5 emissions per year could be decreased by 66.38, 7.15, 24.79 and 36.96 kg by the usage of electric heaters, while the potential reductions were 67.79, 9.97, 25.35 and 38.52 kg when applying heat pump. However, the electric heater was not suitable for wide used due to its low energy efficiency, which is 33.7%. The annual emission reductions of SO₂, NO_x, smoke dust and integrated PM_2.5 in the Beijing-Tianjin-Hebei region were 24.47×104, 3.60×104, 9.15×104 and 13.91×104 t respectively per year by replacing scattered coal burning with low temperature air source heat pumps. However,the annual emmission reductions of SO₂, NO_x, smoke dust and integrated PM_2.5 were 1.28×104, 4.25×104, 1.30×104 and 2.31×104 t respectively by implementing the super-clean emission technology in coal-fired power plants. The reduction of the integrated PM_2.5 emissions for heating was 6.0 times higher than implementing the super-clean emissions in coal-fired power plants. In addition, the investment cost of the low temperature air source heat pump was four hundred million RMB lower than implementing the super-clean emissions in coal-fired power plants. Therefore, the low temperature air source heat pump features lower emissions, better economics and is more flexible.