Wastewater treatment process system and method for wet desulfurization

Abstract

The invention discloses a wastewater treatment process system and method for wet desulfurization. A main flue of the system is internally provided with a first group of nozzles; a bypass flue which isarranged in parallel to an air pre-heater is internally provided with a second group of nozzles; an adjustable air door is arranged at an inlet of the bypass flue; a control valve is arranged betweena feeding pump and the first and second groups of nozzles to control pressure to output wastewater to the first group of nozzles and / or the second group of nozzles; a first temperature sensor is arranged at the head end of an evaporation region of the main flue; and a controller outputs a control signal to the control valve and the control end of the adjustable air door according to a temperatureacquired by the first temperature sensor and a preset main flue beginning injection temperature threshold value to adjust starting and stopping control matched with the first group of nozzles and thesecond group of nozzles. The wastewater treatment process system and method provided by the invention can fully utilize smoke waste heat and reasonably deploy two evaporation regions, can greatly lower the system investment and running costs and does not produce new solid wastes.

Description

technical field [0001] The invention relates to the technical field of thermal coal-fired unit environmental protection, in particular to a process system and method for wet desulfurization wastewater treatment. Background technique [0002] With the continuous increase of environmental protection, flue gas desulfurization devices have been generally installed in the thermal power industry. As we all know, limestone-gypsum wet flue gas desulfurization (WFGD) technology has become the leading flue gas desulfurization technology at home and abroad because of its advantages such as wide application range of coal types and high desulfurization efficiency. In the process of flue gas scrubbing by wet desulfurization, the flue gas fly ash is washed into the gypsum slurry, and harmful substances such as chloride ions and heavy metal ions contained in it also enter the flue gas desulfurization system; and during the gypsum treatment process, As the flushing water enters the desulfur...

AI Technical Summary

Problems solved by technology

Among them, the amount of wastewater treated by spraying and evaporating the main flue after the air preheater is limited, and it is impossible to achieve zero discharge of wastewater. It is often necessary to concentrate and reduce the desulfurization wastewater; and any equipment system for concentration and reduction is very large and complex, and equipment investment The cost is high, it takes up a lot of space, the amount of maintenance is also large, and new solid waste is generated

Among them, the amount of waste water that can be treated by spraying and evaporating the high-temperature bypass flue before the air preheater is large, but the amount of high-temperature flue gas extracted is large, and the temperature drop of the primary and secondary air is too large, so the impact on the boiler efficiency is also great. In addition, if the primary and secondary air temperature drops too much, the flow rate of the air preheater will decrease, and secondary problems such as increased ash accumulation, aggravated low-temperature corrosion at the cold end, and aggravated ammonium bisulfate adhesion and blockage will occur.

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