A multi-effect distillation seawater desalination system using waste heat from power stations

Abstract

The invention relates to a multiple-effect distillation seawater desalination system adopting power station waste heat. Seawater is pretreated through a pretreatment system and then sent to a condenser, and seawater flowing out of the condenser is divided by a pipeline to enter an N-effect evaporator and a heat exchanger; meanwhile, seawater is heated by the heat exchanger by means of low-temperature smoke, smoke waste heat is recovered to obtain steam, steam is introduced into a first-effect evaporator to provide a heat source for multiple-effect distillation seawater desalination, desalted water is obtained through desalination treatment of seawater by means of the low-temperature multiple-effect distillation technique, condensation of steam flowing out of a final-effect evaporator and seawater preheating are conducted by means of the condenser, and strong brine in the N-effect evaporator and the heat exchanger is sent to a salt chemical engineering technological unit. By recycling low-temperature smoke waste heat of coal-fired power plants, low-cost seawater desalination production is achieved, and secondary pollution is avoided in the whole process.

Description

technical field [0001] The invention belongs to the technical field of recovery and utilization of waste heat and energy resources of coal-fired power stations and seawater desalination, and in particular relates to a multi-effect distillation seawater desalination system utilizing waste heat of power stations. Background technique [0002] my country's total water resources ranks sixth in the world, but its per capita water resources ranks 108th in the world, making it a country with severe shortage of water resources. The "Twelfth Five-Year Plan" for the Development of Seawater Desalination Industry pointed out that seawater desalination water is a new water source that can be used for production and living. As an important supplement and strategic reserve of water resources, seawater desalination should be included in the overall planning and allocation of water resources. Seawater desalination industry is a strategic emerging industry and a new economic growth point. H...

AI Technical Summary

Problems solved by technology

At the same time, there are still some problems to be solved during the operation of the GGH (flue gas heat exchanger) in the existing coal-fired power plants at this stage: (1) The temperature of the flue gas after reheating by the GGH is about 80°C, which is much lower than that of the wet method Flue gas acid dew point temperature after desulfurization, so downstream of FGD (flue gas desulfurization), there is still flue and chimney pitting corrosion

(2) When GGH operates below the acid dew point, there will be a large amount of viscous and thick acid liquid, which will adhere to the fly ash in the flue gas, thereby blocking the GGH, increasing the pressure drop, and affecting heat transfer. The flue gas temperature at the inlet of the desulfurization tower is too high, which will cause Cooling water consumption has increased dramatically

(3) GGH covers a large area and requires high maintenance costs

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