Zero emission treatment system and zero emission treatment method for desulfurization waste water from ultra-supercritical circulating fluid bed (CFB) boiler

Abstract

The invention discloses a zero emission treatment system and a zero emission treatment method for desulfurization waste water from an ultra-supercritical circulating fluid bed (CFB) boiler. The zero emission treatment system comprises a chemical pretreatment system, a membrane filtration system, an electrodialysis system, a desulfurization waste water preheating system, a desulfurization waste water evaporator, a solid-liquid separation device and a vapor condensation device. High-temperature flue gas at an exit position of a cyclone separator of the ultra-supercritical CFB boiler is used as aheat source to evaporate and crystallize the desulfurization waste water, superheated steam at an inlet header of a rear platen superheater of the super-supercritical CFB boiler is used as a heat source for the preheated desulfurization waste water, and the membrane filtration system provided with a microfiltration device and the electrodialysis system used for concentration reduction are additionally arranged, so that the defects of high energy consumption and high equipment investment cost of the existing multi-effect evaporation technology are overcome, the desulfurization efficiency can be improved, equipment scaling is effectively avoided, system handling load is reduced, economic benefit is significantly improved, the energy is saved, and the operating cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of circulating fluidized bed boilers, and in particular relates to a zero-discharge treatment system and method for ultra-supercritical CFB boiler desulfurization wastewater. Background technique [0002] In recent years, circulating fluidized bed (CFB) boilers have developed rapidly due to their advantages in fuel adaptability, energy saving and environmental protection. They are an important way to realize efficient and clean utilization of inferior coal fuels in my country, and their development trend is closer to the direction of high parameters and large capacity. . Up to now, 13 supercritical CFB boiler units have been put into production in my country, reaching the world's leading level. With the deepening of research and market demand, ultra-supercritical CFB boilers have become the key research objects of countries all over the world. SO 2 As one of the pollutants discharged by power plants, it wil...

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Problems solved by technology

[0005] Aiming at the above-mentioned problems caused by the limestone spraying technology in the furnace of the existing ultra-supercritical CFB boiler and the shortcomings of the existing desulfurization wastewater treatment method, the present invention proposes a method that utilizes the outlet of the cyclone separator of the ultra-supercritical CFB boiler. High-temperature flue gas is used as a heat source to drive the evaporation and crystallization of desulfurization wastewater, and the superheated steam imported from the rear screen superheater is used to preheat the desulfurization wastewater zero-discharge treatment system and method. The system can improve desulfurization efficiency and effectively avoid scaling of system equipment. High-temperature flue gas can be used as a heat source to fully evaporate desulfurization wastewater by using only one-effect evaporator to reduce investment and operation costs. A new safe and efficient way

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