Introduction of special evaporation system for wastewater treatment:

The importance and urgency of wastewater treatment have now been paid more and more attention by people. Generally speaking, the composition of wastewater is more complex, usually wastewater containing salt. The salt must be removed before biochemical treatment. There are two methods: cold treatment and heat treatment. The so-called cold treatment is the use of membrane separation or reverse osmosis. However, cold separation can not completely remove salt, but the condensed water obtained by thermal separation (that is, the method of evaporation) can completely remove the salt. , The obtained condensed water can be reused as process water or biochemically treated to obtain water up to the discharge standard.

  Wastewater treatment generally has the following characteristics: 1. Large processing capacity; 2. Generally, no economic benefits will be produced in the process of its own treatment; 3. From the concept of waste water, it is a non-heat sensitive material.

In view of the above characteristics, the wastewater treatment system should be combined with one-time investment and operating costs from a design perspective. From the perspective of operating costs, it mainly depends on the amount of steam. Therefore, it is more reasonable to adopt a multi-effect rising film evaporation system. But the higher the number of stages, the higher the primary steam pressure required, the more control points between stages and the larger the one-time investment. Therefore, each system must be personalized according to the actual situation, and at the same time According to the composition of the wastewater, choose the co-current type, counter-current type, parallel-flow type or even cross-flow type:

  The downstream type is conducive to the transportation of materials between stages (materials always go from the high pressure section to the low pressure section);

The counter-current type is suitable for materials with low boiling point components (compared to water), otherwise the secondary steam produced contains low boiling point non-condensable gas, which cannot drive the next stage evaporator;

Cross-flow type is a combination of downstream and upstream (only possible with three effects or more);

The parallel flow type is simple to operate and control, and the evaporation conditions of each stage are basically the same;

Therefore, the evaporation system for wastewater treatment must be tailored to the characteristics of the wastewater.

The difference between the wastewater treatment multi-effect evaporation system and the general multi-effect evaporation system is that there is salt precipitation (crystal production) during the evaporation process, so the crystals must be smoothly discharged from the system, and the system must continue to operate normally. Therefore, it is necessary to add a salt collection system on the basis of the general system. At the same time, it is necessary to consider that the crystals in the supersaturated solution cannot accumulate on the wall of the heating tube, otherwise the evaporation system will fail. Therefore, it is based on the common multi-effect evaporation system. A forced circulation pump is added to speed up the flow rate of the supersaturated solution in the heating tube, so that the crystals cannot stay on the heating tube wall.