A kind of plate-type hydrophobic polymer double-effect MVR system and wastewater concentration method

Abstract

The invention discloses a plate-type hydrophobic polymer double-effect MVR system. The first-effect MVR evaporator and the second-effect MVR evaporator in the double-effect MVR system are both reactors, which are divided into one-effect evaporation unit and one-effect condensation unit by the plate evaporator, and the plates in the plate evaporator are hydrophobic polymerization physical film. The thickness of the hydrophobic polymer film is 15-60 μm; the contact angle is 110°-150°, the water absorption rate is 0.0042%-0.41%, the thermal expansion coefficient is 44.1-100 μm / (m·℃) at 20°C, and the thermal expansion coefficient at 100°C The temperature is 39.2-140μm / (m·℃), the melting point is 330-340℃, the glass transition temperature is 140-220℃, and the thermal conductivity is 0.2-0.35W / (m·K). The polymer film is used as the base material of the heat exchange surface, and more heat exchange surfaces can be placed in a limited volume. The thermal resistance generated by the polymer film under this film thickness is only equivalent to that of 0.75-1.5mm 316L stainless steel, which can Realize low-temperature differential heat exchange at 2-3°C, reduce heat supplementation, and reduce the weight of the MVR device. At the same time, the existence of flexible groups such as C-N bonds in the polymer film can cause a thermal expansion rate ten times that of stainless steel, which can accelerate the scale layer. The falling off reduces the loss of heat transfer temperature difference.

Description

technical field [0001] The invention relates to a plate-type hydrophobic polymer double-effect MVR system and a wastewater concentration method, belonging to the technical field of water treatment. Background technique [0002] MVR is the abbreviation of Mechanical Vapor Recompression technology (Mechanical Vapor Recompression). The basic principle is to compress the steam evaporated from the evaporation unit and increase the heat enthalpy, and reuse it as a heat source. The advantage of adopting MVR technology is: one effect of evaporation in the MVR system is equivalent to 20 to 30 effects in multi-effect evaporation, and the economy is good, and the operating cost is only about 30% of the traditional multi-effect evaporator; no external steam is needed, and the stand-alone is independent Good performance; using low-temperature evaporation technology, the evaporation temperature is 55-60°C, which is more than 10°C lower than the top temperature of the low-temperature multi...

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Problems solved by technology

[0003] The current MVR system still has problems such as high energy consumption, poor anti-scaling and anti-corrosion performance of the heat exchange surface, inability to achieve zero sewage discharge, and small water treatment volume. At the same time, the steam compressor has high energy consumption and high cost. for further improvement

For example, the plate evaporators used in the current MVR system mostly use S316L stainless steel as the base material of the heat exchange surface. , usually apply a high polymer coating on the surface of the stainless steel substrate, which increases the risk of coating peeling off

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