Single-effect multi-chamber mechanical compression evaporation device for processing high-salinity/high-organic-substance-content wastewater and method thereof

Abstract

The invention discloses a single-effect multi-chamber mechanical compression evaporation device for processing high-salinity / high-organic-substance-content wastewater. The device has advantages of less scale formation, long effective operational cycle, low cleaning frequency and low chemical consumption for cleaning. The device comprises a mechanical vapor compressor, a mixing chamber, a circulating pump, a distilled water tank, a main evaporation body and a thermal scale inhibition system. The main evaporation body is divided into more than two evaporating chambers. Each-stage evaporation system comprises an evaporating chamber, a mixing chamber, a spray system, a heat exchanger bundle, a concentrate pump and a thermal scale inhibition system. All the evaporating chambers share one steam collecting chamber, the mechanical vapor compressor, the heat exchanger bundle and the distilled water tank. high-salinity / high-organic-substance-content wastewater is heated by a distilled water heat exchanger and the heated wastewater enters the mixing chamber of the first-stage evaporation system; a concentrated solution of each evaporation system undergoes scale inhibition through the thermal scale inhibition system and then enters the mixing chamber of the next-stage evaporation system; and a concentrated solution of the last-stage evaporation system is discharged. The invention also discloses a method for processing high-salinity / high-organic-substance-content wastewater by the utilization of the above device. The method has low operation cost and has a good application prospect.

Description

Technical field [0001] The invention relates to a single-effect multi-chamber mechanical recompression evaporation treatment device and method for high-salt / high-organic wastewater. Background technique [0002] Properly treating high-salinity, high-organic wastewater, such as landfill leachate, pharmaceutical wastewater, chemical wastewater, and power plant desulfurization wastewater, so that it can meet discharge standards, has always been a major problem in the field of environmental protection at home and abroad. [0003] At present, the high-salt / high-organic wastewater treatment processes in the domestic environmental protection field are mainly biological + membrane process, DTRO process and heat pump evaporation process. The biochemical + membrane process is relatively mature and stable, but it has shortcomings such as small application range, long process flow, large area, high operating cost, and large investment. At the same time, the final disposal of nearly 30% reverse...

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Problems solved by technology

Among them, the inorganic matter is mainly calcium magnesium silicate, such as calcium carbonate, calcium sulfate, magnesium hydroxide and calcium magnesium silicate deposits, among which calcium salt is the main substance, and the organic matter is mainly humic acid, which evaporates for a certain leachate project Sampling and analysis of scaling in the equipment shows that the calcium and magnesium salt particles constitute the "skeleton", and the humic acid is in the form of colloid, forming the "binder". The scale formed by the combination of the two substances has the characteristics of high hardness, high viscosity, and difficult cleaning. Seriously affect the long-term operation of the equipment; to solve the above scaling problem, the conventional methods include softening method and antiscalant method, and the use of pretreatment agents to soften and remove calcium and magnesium ions will cause high dosing costs, and some calcium and magnesium ions will still remain in the In the original solution, scaling will still occur under high concentration; if the antiscalant is used, the cost of dosing is too high, and due to the complex and diverse components of the pollutants in the high-salt / high organic matter wastewater, some kind of reaction with the antiscalant often occurs , resulting in frequent failure of antiscalants

[0005] Due to the poor heat transfer effect of the scale formed by calcium magnesium silicon salts and humic acid, when the outer wall of the heat exchange tube bundle of the heat pump evaporator is scaled, the heat transfer coefficient of the heat exchange tube is reduced, and the heat exchange temperature difference required for evaporation increases , which increases the temperature rise and pressure that the mechanical steam compressor needs to provide for the secondary steam, thus increasing the energy consumption required for operation

In addition, since the heat exchange tube bundles of the heat pump evaporator are prone to fouling, they need to be shut down frequently for cleaning, which not only increases the chemical consumption for cleaning, but also increases the energy consumption for starting and stopping the heat pump evaporation. The required power consumption is about 300kWh)

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