| Industrial boilers, which consume 400 million tons of coal and emit 6 million tons of SO2 and 8 million tons of PM annually, are one of the most important sources of air pollution in China. Study on air pollutant emissions and energy saving measures of coal-fired industrial boilers are of great significance to the policy-making of air pollution control and the development of energy, environment and society. Field tests showed that the emission concentrations of TSP, SO2, NOx, and CO from coal-fired industrial boilers were 283-350 mg/m3, 914.6-1245.7 mg/m3, 64.2-136.6 mg/m3, and 109.9-890 mg/m3, respectively. The emission factors of TSP, SO2, NOx, and CO were 3.849～20.3 8g/kg, 16.83～54.01 g/kg, 1.441～3.791 g/kg, and 1.50952.56 g/kg, respectively. The emission concentrations of Hg2+, Hg0 and Hgp for the tested boilers were 0.3-5.7μg/m3, 1.5-3.8μg/m3, and 0.008-0.023μg/m3, respectively. The removal efficiencies of wet scrubber for TSP and SO2 were respectively 54.2-73.8% and 13-32.6%. Due to the low removal efficiencies, the air pollution from coal-fired industrial boilers was serious.The coal consumption rate of Shenyang Department of Engineering and Technology during the heating season was 33.5 kg/m2, higher than that of Shenyang city (30 kg/m2). There was large energy saving potential from coal-fired industrial boilers. Through the boiler arch reconstruction, layered combustion technology, internal resistance reduction, wastewater reuse and swirling plate double alkali desulfurization, 900 tons of coal and 2×105 kWh of electricity were saved, and the emission concentrations of TSP and SO2 were reduced from348 mg/m3 to 176 mg/m3 and from 1274 mg/m3 to 815 mg/m3 respectivelyThe measures including improvement of operation skills and management, enhancement of coal use management, enhancement of water quality management, adjustment of combustion, clearing the heating surface dust, heat loss reduction, and pollution emission control were implemented to improve the boiler's efficiency and save 200 tons of coal. The pollutant emissions were also reduced. The economic and environmental benefits of measures taken by Shenyang Department of Engineering and Technology were analyzed to indicate the energy saving and pollution reduction of coal-fired industrial boilers. The economic investment of energy efficiency projects was 0.49 million RMB, the benefit of energy saving was 0.768 thousand RMB per year, and the investment recovery period was 0.638 year. The environmental investment was 2.16 million RMB in the project, the environmental benefit was 0.4 million RMB per year, and the payback period was 5.4 years. The extension analysis indicated that with these energy-saving measures, annually 0.3267 million tons of coal would be saved in Shenyang, both the operating costs and pollutant emissions would be significantly reduced.
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