MVR evaporator technical principle

After the secondary steam generated by the evaporator is used by the steam compressor, the low-grade steam is compressed to a high-grade steam with a higher saturation temperature, and returned to the heating heat source of the evaporator to replace most of the raw steam. The steam is only used to supplement the heat loss and the enthalpy required to supplement the temperature difference between the inlet and outlet materials, thereby reducing the raw steam consumption of the evaporator and achieving the purpose of energy saving.

Advantages of MVR evaporator

1. High heat transfer coefficient: The evaporator with this structure has a changeable flow field, which makes the material liquid easily reach a vigorous turbulent state, and its heat transfer coefficient is 2-3 times that of the tube-and-tube type;

2. Not easy to clog: the feed liquid forms a turbulent flow on the heat exchange surface, which can wash the heat exchange surface and make the scaling body adhered to the heat exchange surface fall off, delaying the scaling cycle;

3. The surface is very smooth: using mature processing technology, the surface roughness of the heat exchange surface is controlled at a very low value, making it difficult for pollutants to adhere. The fouling rate of this type of heat exchanger is only 1/5 of that of the shell and tube heat exchanger;

4. Easy to clean and maintain: the plate structure is adopted, the heat exchange surface can be easily disassembled, and any polluted or damaged heat exchange surface can be easily replaced.

Scope of application:

  Evaporation and crystallization of various inorganic salts, evaporation of materials with high hardness, evaporation and concentration of garbage permeate, concentration of materials in food, fermentation, and pharmaceutical industries, and concentration of heat-sensitive materials.

MVR evaporator design considerations:

1. The water quality and inlet conditions of the MVR evaporator affect the process data and parameters of the MVR evaporator. When designing the MVR evaporator, the process of the MVR evaporator will be customized according to the water quality of the owner.

2. The processing capacity and evaporation of the water quality of the material determine the size of the MVR evaporator. The water quality of the material determines the material of the heat exchanger and the evaporator, and also determines the investment of the entire MVR evaporator.

3. The solubility and temperature rise of the material determine the selection of the steam compressor in the design scheme of the MVR evaporator.

4. The production method on site determines the operation method of the MVR evaporator. The operation mode of the whole set of MVR evaporator is to use continuous evaporation operation or intermittent evaporation operation, and the operation mode of the MVR evaporator should be determined according to the customer's production method.

Principle of multiple effect evaporator

From the relatively primitive evaporator to a single-effect, double-effect, three-effect, four-effect or more effect evaporator, the purpose is to gradually reduce energy consumption. The multi-effect evaporator uses the secondary steam generated by the evaporation of the previous effect to provide the heat source for the next effect to achieve the purpose of energy saving. Multiple effects can recover part of the secondary steam, the more the number of effects, the more secondary steam recovered. This is different from the MVR evaporator which can recover all the secondary steam. Multi-effect evaporation systems often consider recovering the heat of condensed water or secondary steam to achieve the purpose of energy saving. In wastewater treatment, automatic online cleaning of preheater fouling should also be considered.

Multi-effect evaporator energy consumption

Generally speaking: single-effect evaporation consumes 1.1-1.2 tons of steam per ton of water, double-effect evaporation consumes 0.6-0.7 tons of steam per ton of water, three-effect evaporation consumes 0.37-0.46 tons of steam per ton of water, and four-effect evaporation consumes per ton of water 0.3~0.35 tons of steam, five-effect evaporation consumes 0.24~0.3 tons of steam per ton of water.