A method and device for capillary low-temperature evaporation of high-salt wastewater

Abstract

The invention relates to a method and a device for capillary low-temperature evaporation of high-salt waste water. The method adopts the evaporator of the PTFE capillary tube carried by the multi-layer gas distribution plate and uses the waste heat of the flue gas as the heat source. The PTFE capillary tube evaporator is the core equipment and is suitable for the process method of evaporating high-salt wastewater. In the plate carrier gas evaporator In the process, each group of capillary tubes is laid on the distribution plate in a serpentine shape, and through horizontal arrangement of multiple layers, the problem of corrosion and fouling of the evaporator is solved, and the initial investment, operation and maintenance costs of the evaporator are reduced. The invention realizes waste heat recovery, without It needs to consume steam once, which significantly improves the effect of energy saving and emission reduction, and has important economic and social benefits.

Description

technical field [0001] The invention relates to the technical field of high-salt wastewater treatment, in particular to a process and device for capillary low-temperature evaporation of high-salt wastewater. Background technique [0002] High-salt wastewater refers to wastewater containing total dissolved solids (Total Dissolved Solid) and organic matter with a mass fraction greater than or equal to 3.5%, including high-salt domestic wastewater and high-salt industrial wastewater. With the development of my country's industry, the production of high-salt industrial wastewater is becoming more and more extensive, and the amount of wastewater is also increasing year by year. In addition to organic pollutants, these wastewater also contain a large amount of inorganic salts, such as Cl - , SO 4 2- 、Na + Plasma. Due to the complex composition, high concentration of organic matter, and high salt content of these wastewaters, it is difficult to directly use economical biochemic...

AI Technical Summary

Problems solved by technology

The evaporative desalination method is to vaporize and remove part of the water in the high-salt wastewater by heating, so as to increase the concentration of the solution and create conditions for the precipitation of solutes. , high maintenance costs, and a relatively large demand for steam or electric energy limit the application of evaporation technology in this field to a certain extent

[0004] In recent years, people are committed to improving the research and development of evaporation technology and equipment, and have also developed such as multi-effect evaporation technology (including low-temperature multi-effect evaporation technology), mechanical vapor recompression cycle evaporation technology, multi-stage flash evaporation technology, membrane distillation technology, etc., However, there are some problems in practical application

Among them, the multi-stage flash evaporation technology (MSF) has the disadvantages of low thermodynamic efficiency, high energy consumption, serious scaling and corrosion of equipment; multi-effect evaporation technology (including low-temperature multi-effect evaporation technology) (MED) has high investment costs; The compression cycle evaporation technology (MVR) has a high demand for electric energy and a large investment in equipment

At the same time, in the above three technologies, the corrosion of the concentration equipment is also a very serious problem, threatening the service life and safe operation of the equipment

Membrane distillation technology (MD) is currently mostly still in the laboratory or small-scale test stage, and there are still many deficiencies in membrane distillation, such as low heat transfer efficiency in the heat conduction process, easy blockage of membrane pores, high cost of membrane structure, Large limitations, membrane materials still need to be improved, etc.

Utility model patents CN201520409597 and CN200920258793.1 respectively disclose a capillary plate heat exchanger installed in a sheet metal shell and an evaporator capillary fixing structure (the capillary is wound on a copper tube and fixed by welding), the above patent Demonstrated a high-efficiency evaporative heat exchanger used in the air-conditioning and HVAC industry. Most of the capillary tubes are made of copper, which is expensive and not resistant to corrosion by inorganic salts; the invention patent CN201610133457 discloses a distribution plate, a tube wall heating tube, and a demister. The carrier gas evaporator has a limited contact area between the heating tube and the evaporation medium at the cylinder wall, and the heating tube is not completely immersed in the heating medium, so the heat transfer efficiency is low

Images