Abstract: During the transformation of power generation enterprise and corresponding equipment upgrade, it is inevitable to build large- capacity and high-parameter units on the original site with old small units which were shut down and demolished due to the requirements of this technical reform. The construction of a complete set of high-efficiency electrostatic precipitators and gas purification facilities such as desulfurization and denitrification facilities can significantly reduce the pollutant emissions. Taking the Unit 1 in the transformation and expansion project of Huozhou Coal-Fired Power Plant for instance, the paper introduces the effects of the SCR denitrification equipment, five-field electrostatic precipitator and wet flue gas desulphurization(WFGD) equipment on the removal of NO_x, dust and SO₂ produced during coal combustion. Field tests show that under the full load condition, the NO_x removal efficiency by the A and B sides of SCR is in the range from 70% to 80%, while the dust removal efficiency by the electrostatic precipitator is around 99.85%, and the SO₂ removal efficiency by the WFGD equipment is over 98%, which meet all the present standards related to pollutant emissions from coal-fired power plants. Moreover, in comparison with the demolished four 100-MW units, the total emissions from the two newly built 600-MW units have decreased significantly, which proves that the substitution of small units with large ones can definitely attain the goal of generation increase and emission reduction.

Key words: 600-MW coal-fired unit, SCR denitrification equipment, electrostatic precipitator(ESP), wet flue gas desulphurization (WFGD), pollutant emission