Energy-saving distillation and desalination system and method based on waste heat utilization of waste hot water in iron and steel plants

Abstract

The invention discloses an energy-saving distillation desalination system and method based on steel plant waste hot water waste heat utilization. The system comprises a head evaporation set, a middle evaporation set, a tail evaporation set, a condenser, a product water flash tank, a product water balance tank, a concentrated brine flash tank, a concentrated brine balance tank, a raw material water pump, a cooling water pump, a product water pump, a concentrated brine pump, a tail evaporation set feed pump, a middle evaporation set feed pump, a head evaporation set feed pump, a vacuum system, a steam jet pump, a high-pressure steam inlet valve, an air evacuation valve, a high-pressure steam changeover valve, a low-pressure steam changeover valve, a regulating valve, a heat exchanger, a steam flash tank, a demister, a first-effect condensation water regulating valve, a water return valve, a water return pump, a waste hot water waste heat steam changeover valve, a feed preheater and a hot water discharge pump. The method can recycle waste hot water waste heat resources to generate low-grade steam, and combines the low-grade steam generated by the waste heat resources with LT-MED seawater desalination, thereby lowering the cost and implementing energy saving and consumption reduction.

Description

technical field [0001] The invention relates to the technical field of distilled seawater desalination and the recovery and utilization of waste heat and energy in iron and steel plants, in particular to an energy-saving distillation and desalination system and method based on the utilization of waste hot water and waste heat in iron and steel plants. Background technique [0002] Seawater desalination is a water source incremental technology to obtain fresh water from seawater, and it is a reliable way to solve the shortage of fresh water resources and ensure water safety. According to different separation technology principles, seawater desalination can usually be divided into distillation methods that mainly consume heat energy (such as multi-stage flash evaporation, multi-effect distillation, pressure steam distillation, etc.) and membrane methods that mainly consume electric energy (such as electrodialysis). , reverse osmosis, etc.) two categories. Among them, the heat...

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Problems solved by technology

Among them, in terms of the current recovery and utilization of waste heat in my country's iron and steel plants, high-temperature waste heat is recovered the most, with a recovery rate of about 50%; followed by medium-temperature waste heat, with a recovery rate of about 40%; thirdly, low-temperature waste heat, with a recovery rate of less than 1%.

[0006] Through the above analysis, it can be seen that recycling the waste heat resources of iron and steel plants for seawater desalination is a feasible technical method to reduce the cost of water production. At present, the use of steel plant blast furnace gas, high-temperature slag washing water, waste steam, and low-temperature waste flue gas to desalinate seawater has been developed. desalination technology, but how to use the low-grade waste hot water waste heat of the iron and steel plant, and realize the matching between the two according to the heat source requirements of seawater desalination, there is still no effective process method

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