Flue gas prewashing method for energy conservation and consumption reduction of wet flue gas desulfurization system

Abstract

The invention discloses a flue gas prewashing method for energy conservation and consumption reduction of a wet flue gas desulfurization system. The method includes following steps: replenishing water into a prewashing size buffer tank; starting a prewashing size buffer tank stirrer, and continuing replenishing water into the prewashing size buffer tank; starting a prewashing size circulating pump, gathering waste liquid after washing at the bottom of an induced draft fan flue, and enabling the waste liquid to automatically flow into a prewashing drainage pit through a drainage port of the induced draft fan flue; starting a prewashing drainage pit stirrer, and continuing discharging the waste liquid into the prewashing drainage pit; turning off the prewashing size circulating pump, and turning on a prewashing drainage pit pump to discharge washing liquid into the prewashing size buffer tank for recycling use; stopping the prewashing drainage pit pump when liquid level of the prewashing drainage pit lowers to not greater than 2m; repeating the above steps until a flue gas detection index is lower than a designed value, and pumping flue gas into an inlet of an absorption tower. By the flue gas prewashing method, the defect that the flue gas contains much oil dirt and is high in temperature and dust concentration in the prior art is overcome.

Description

technical field [0001] The invention relates to the field of desulfurization equipment, in particular to a flue gas pre-washing method for energy saving and consumption reduction of a wet flue gas desulfurization system. Background technique [0002] At present, the desulfurization of thermal power units in my country mainly adopts limestone / gypsum wet flue gas desulfurization technology, which not only reduces the emission of air pollutants in power plants and improves the environment, but also significantly increases energy consumption; FGD (limestone / gypsum wet flue gas desulfurization) The system is mainly composed of flue gas subsystem, SO 2 Absorption subsystem, limestone slurry preparation and supply subsystem, gypsum dehydration subsystem and accident slurry subsystem, etc. Each subsystem includes many energy-consuming equipment such as pumps and fans, and the energy consumption characteristics of each energy-consuming equipment vary greatly; Among them, the booster ...

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Problems solved by technology

[0004] However, after canceling the FGD (limestone / gypsum wet flue gas desulfurization) system flue gas bypass, any flue gas generated during the operation of the main engine will enter the desulfurization system at all times, and the soot concentration at the FGD (limestone / gypsum wet flue gas desulfurization) inlet It also affects the normal operation and power consumption of the desulfurization device; the main reason is that after a long period of operation, the acid-insoluble matter and fly ash in the flue dust are easily deposited in the flue, fan blades, GGH (flue gas-flue gas reheater) Deposition and fouling on equipment such as demisters and demisters will increase system resistance and increase power consumption of induced draft fans; in addition, heavy metals and fluoride ions in the smoke have a shielding effect on the dissolution of limestone; the smoke concentration remains high for a long time level, the pH value of the slurry in the absorption tower will be low, and the amount of limestone slurry will be additionally increased, resulting in prolonged running time of the ball mill and increased power consumption; therefore, the technical problem that needs to be solved is to eliminate the above-mentioned adverse effects after canceling the bypass to ensure desulfurization Normal operation of the system after bypass removal

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