Method and device for treating high-salinity wastewater by using rotary membrane evaporator

Abstract

A device for treating high-salinity wastewater by a rotary membrane evaporator comprises the rotary membrane evaporator, a steam compressor and a heat exchanger, and the evaporator adopts a vertical evaporation mode. The steam compressor compresses steam generated by a power plant boiler, and the compressed steam heats an inner shell of the evaporator. High-salinity wastewater is heated by the heat exchanger and then evenly distributed on the inner shell through a distributor to flow downwards, a magnetic scraper spreads the high-salinity wastewater flowing downwards, and salt scales left on the surface of the inner shell after the wastewater is evaporated are scraped down. A bottom scraper welded with a protective cover is arranged at the bottom of the evaporator, a main shaft drives thebottom scraper to rotate to scrape salt deposit deposited at the bottom, and a concentrated solution is discharged from a concentrated solution outlet. Wastewater steam is condensed and discharged through a drain valve. The device solves the problems that a conventional rotary film evaporator bearing is easy to abrade, difficult to replace and easy to corrode, the magnetic scraper is arranged to solve the problem that the concentration effect becomes poor due to the fact that a common scraper is easy to abrade, the bottom scraper is arranged at the bottom to prevent the concentrated solution outlet from being blocked, and an MVR technology is adopted to save more energy.

Description

technical field [0001] The invention belongs to a high-salt wastewater evaporation treatment device. Background technique [0002] With the development of my country's industrialization process, coal-fired power stations and chemical enterprises produce a large amount of high-salt wastewater. Impurities in high-salt wastewater mainly contain Ca 2+ , Mg 2+ , SO 4 2- , Cl - 、Na + etc., some also have pollutants such as chromium, cadmium, mercury, arsenic, lead, nickel, etc. This type of wastewater has poor biodegradability and contains a large amount of calcium and magnesium ions, which can easily cause equipment blockage. [0003] The widely used method of evaporating high-salt wastewater is forced circulation evaporation. In order to ensure that the pipelines of the equipment are not blocked by forced circulation, the circulation speed must be above 2.5m / s, the power of the circulation pump is large, and the power consumption is large. The rotary film evaporator use...

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Problems solved by technology

[0006] 1. The scraper is easy to wear after the evaporator runs for a period of time

[0007] 2. The bottom bearing is driven by the motor, which is easy to wear under the action of radial force, and it is inconvenient to replace the bearing inside the evaporator. If it is replaced frequently, it will affect the normal operation of production and increase the repair cost

[0008] 3. The high-salt wastewater contains a relatively high concentration of Cl - , during the evaporation process, the waste water is easy to flow into the bottom bearing along the main shaft and cause corrosion to the bearing

[0009] 4. High-salt wastewater contains a large amount of suspended matter, which is easy to scale on the inner wall of the evaporator, and deposits at the bottom of the evaporator in a short period of time, easily causing blockage of the evaporator outlet

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