Evaporator plays an important role in industry, among which the two main types are MVR evaporator and multi-effect evaporator. What is the difference between MVR evaporator and multi-effect evaporator?
Let Nanjing Gaojie Light Industry Equipment Co., Ltd. introduce the difference between these two kinds of evaporators.
This is the current problem for MVR evaporator and multi-effect evaporator consultation, often have owners in the purchase of evaporator will compare MVR evaporator and multi-effect evaporator, need to understand the difference between MVR evaporator and multi-effect evaporator.
MVR evaporator is the secondary steam mechanical compression evaporator, which uses the steam compressor to re-compress the evaporated secondary steam to raise its temperature, and then send it into the evaporation heater for repeated use.
MVR evaporator basically does not need to consume raw steam, but only consumes part of the electric energy, which mainly depends on the temperature rise required by the secondary steam and the efficiency of the steam compressor.
Multi-effect evaporator is an evaporator designed for repeated reuse of secondary steam by using the temperature difference from the first effect to the last effect. Generally, the evaporation temperature of the first effect evaporation is controlled by the heat sensitivity temperature of the material, and the temperature of the last effect secondary steam is determined by the local altitude and the selection of vacuum unit.
The consumption of raw steam is inversely proportional to the number of active solids.
MVR evaporators and the difference between the multiple effect evaporator is heating steam consumption of the main difference, the difference between the rate of cooling water, heat input, cover an area of an area the size of the difference, the difference between operating system, the difference between the comprehensive energy saving effect MVR evaporators is better than that of multiple effect evaporator, but with the MVR evaporators price is higher than the rate of multiple effect evaporator.
Cause of too low vacuum in evaporator during operation
The evaporator causes too low vacuum during operation:
The concentrator leaks into the air, and the air intake can put extra pressure on the vacuum system, which in severe cases may not even be able to vacuum.
Insufficient cooling water.
In addition to the pump equipment, the main cause of insufficient cooling water is pipe blockage and valve damage.
Insufficient cooling water will prevent the secondary steam from condensing in time and seriously affect the operation of vacuum system.
If the temperature of cooling water is too high and the inlet temperature of cooling water is too high, a large number of secondary steam generated by concentration heating cannot be maintained in time, the vacuum degree of thickening device drops sharply, and the vacuum of thickening equipment decreases rapidly.
If the heating vapor pressure is too high, the evaporation rate of the concentrator will increase rapidly, and the load on the cooling unit will increase and the vacuum degree will gradually decrease due to the large number of secondary vapors produced.
Reducing the vacuum degree will increase the evaporation temperature of the material, which will not only affect the quality of the product, but also ultimately affect the production capacity of the equipment.
What are the characteristics of the forced circulation evaporator?
Evaporators are characterized by:
1. The liquid circulation speed is adjusted by the pump.
2. When the material liquid runs at a high flow rate under the action of external force, the scaling rate is reduced, the turbulence state of the material liquid is enhanced, and a certain amount of pressure head is ensured at the exit end, which can prevent the evaporation in the heat exchanger.
3. Forced circulation The circulation of evaporative solution in the equipment mainly depends on the forced flow generated by the external power.
The speed can generally reach 1.0-3.5m/s.
Heat transfer efficiency and production capacity is large.
4. The raw material liquid is driven from bottom to top by the circulating pump and flows upward along the inside of the heating chamber.
5. The material in the heat exchanger does not evaporate, flash in the separator, steam in the separator from the upper discharge, fluid blocked falling, cone bottom is sucked into the circulating pump, and then into the heating pipe, continue to cycle.
To sum up, the advantages of forced circulation evaporator are: anti-salting out, anti-scaling, easy cleaning, strong adaptability.
What are the characteristics and scope of application of forced circulation evaporator?
Evaporator is the use of external power for circulation, with a pump to force the solution along one direction at a speed of 2-5m/s through the heater.
Other evaporators are vaporized in the evaporator.
Their common deficiency is that the circulation velocity of the solution is low and the heat transfer effect is poor.
Forced circulation evaporator can be used when dealing with solutions with high viscosity, easy scaling or easy crystallization.
Features of forced circulation evaporator:
1. The advantages of forced circulation evaporator: large heat transfer coefficient, anti-salting-out, anti-scaling, strong adaptability, easy to clean.
2. Disadvantages of forced circulation evaporator: large consumption of kinetic energy, long residence time of solution;
The cost of construction and maintenance is slightly higher.
Application scope of forced circulation evaporator:
Forced circulation evaporator, suitable for scaling, crystallization, heat sensitivity (low temperature), high concentration, high viscosity and containing insoluble solids and other chemical, food, pharmaceutical, environmental protection engineering, waste liquid evaporation recovery and other industries of evaporation and concentration.