Abstract: In view of the requirements of ultra-low SO₂ and dust emission in coal-fired power plants, the currently widely-used technologies of high-efficiency desulfurization, collaborative dust removal of desulfurization system and wet electrostatic precipitator have been briefly described. Taking the example of ultra-low SO₂ and dust emission renovation in 600 MW units burning coal with high sulfur and high ash content, the techno-economic assessment has been performed to study the scheme of double-tower double-cycle collaborative desulfurization and dust removal (i.e. scheme one) and the scheme of double-tower double-cycle design equipped with wet electrostatic precipitator (i.e. scheme two) in terms of technical parameters, engineering work load, adaptability, investment expense and the cost of operation. The comparison result shows that the scheme one comes with less renovation engineering work load, maintenance work load or additional auxiliary power consumption of power plant, while scheme two has advantages over scheme one in the aspects of the adaptabilities of unit load and inlet dust concentration, the physicochemical property sensitivities of dust and the operation stability. Although the total investment expense and the cost of operation and maintenance of scheme two are higher than those of scheme one, scheme two is capable of promoting further collaborative SO₃ removal and contributing to eliminating the issue of blue smoke plume.

Key words: coal-fired power plant, ultra-low emission, flue gas treatment, blue plume treatment, efficient desulfurization, collaborative dust removal, double-tower double-cycle, wet electrostatic precipitator, techno-economic analysis