Selection of typical wet desulfurization system and economic analysis of variable load operation for industrial coal-fired boilers

In this paper, the operation costs of wet flue gas desulfurization based on MgO, CaO and CaCO3 under basic, special and ultra-low emission limits are analyzed from the unit price of desulfurizer and electricity price. Guidance about desulfurizer selection in Liaoning Province under different electricity prices and different loads is given. The results show that the desulfurization cost of MgO is greatly affected by the desulfurizer price, while the CaCO₃ is more sensitive to the fluctuation of electricity price, and the CaO is between the two. In Liaoning Province, the overall economy of CaCO₃ is relatively poor in the whole range of electricity price, while CaO and MgO perform better. The former has obvious advantages at low electricity price, while the latter is preferred at high. With the emission standard becoming stricter, the dominant range of CaO is expanded. When the boiler load changes, the power consumption cost and desulfurizer cost also change accordingly under different emission requirements. When the electricity price of Liaoning Province is 0.8 RMB/kWh, no matter under which emission limit, the operation cost of MgO is always the lowest under the considered loads, followed by CaO, and the economy of CaCO₃ is the worst.