Multiple-effect evaporative crystallization system and method for utilizing compressed air and heat pump to dispose wastewater containing salts in power plant

Abstract

The invention discloses a multiple-effect evaporative crystallization system and method for utilizing compressed air and a heat pump to dispose wastewater containing salts in a power plant. Accordingto the method, the compressed air is introduced from an air separation device of the fuel gas power plant to assist in atomization of the wastewater containing the salts in the power plant, the air (waste gas) which is already used for assisting in atomization serves as a heat source of the heat pump to be conveyed into a heat pump evaporator through a draught fan, the waste gas is cooled, dehumidified and then recovered, and condensed water generated by using the evaporator for condensing vapor in the air is discharged at regular intervals; predisposed wastewater of the power plant flows intoa heat pump condenser for heat exchange and preheating with refrigerating fluid vapor at first; contact-type mass transferring concentration is conducted on the preheated wastewater and the waste gascooled and dehumidified by the evaporator in a concentration chamber, and the concentrated wastewater with high concentration flows into a multi-level flash evaporation device for flash evaporation.Desalted water generated during flash evaporation converges at a water collecting tank, circulating wastewater in the flash evaporation device flows into a spraying chamber for further atomized concentration with the assistance from the compressed air, the wastewater containing the salts is evaporated in the spraying chamber till complete crystallization, and generated crystallized salts are stacked at a discharging port in the bottom of the spraying chamber and removed by a scraper at regular time. The system fully utilizes waste heat and achieves energy gradient utilization and zero discharge of the wastewater in the power plant.

Description

technical field [0001] The invention relates to a multi-effect evaporation crystallization system and method for treating salty waste water of a power plant by using compressed air and a heat pump, and belongs to the technical field of power plant waste water treatment and heat pumps. Background technique [0002] Water resources and water environment issues have become bottlenecks restricting industrial development. "Zero discharge of wastewater" is being mentioned more and more in thermal power enterprises, and the high-salt wastewater in power plants is the key to realize zero discharge of wastewater. For the recycling or product reprocessing of concentrated brine, it will be an extremely challenging and significant task to achieve zero discharge in the desalination process of brine. [0003] Heat pump technology is a mature and energy-saving technology that uses low-grade heat sources. Applying heat pump technology to recover waste heat and preheat waste water is an eff...

AI Technical Summary

Problems solved by technology

However, this process technology also has many disadvantages: large power consumption, small operating flexibility of the equipment, not suitable for occasions with large changes in water production, etc.

Compressed air is used for the atomized waste gas, which still has a certain pressure and temperature, and is of value for use. Direct discharge will inevitably cause energy waste

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