Thin film evaporator as a new type of high efficiency evaporation equipment, it is widely used for industrial production has brought enormous economic benefits, in the design of vacuum film evaporator, the heat transfer part of the calculation related to produce products of high quality the important basis of the evaporator, hangzhou Ann research after many years of continuous research and development to optimize the design of the thin film evaporator, summarizes the following optimal design scheme.
Evaporation is one of the most important chemical unit operations. Evaporation is the process of removing water or other volatile solvents from the solution by boiling with heat. The amount of solutes in the solution remains unchanged, so that the solution is concentrated.Therefore, evaporation is a heat transfer process.There are three main evaporation operations in industrial production:
1. To improve the concentration of solute in aqueous solution.
2. To concentrate the solution and recover the solvent.
3. Prepare pure solvent by evaporation.
Evaporation can be done under pressure, atmospheric pressure and vacuum. In order to maintain the system pressure in the production process, evaporation needs to be done under pressure.For heat sensitive materials, in order to ensure product quality, evaporation and concentration at low temperature, the use of vacuum operation to reduce the boiling point of the solution.Therefore, generally no special requirements of the solution, the use of atmospheric pressure evaporation is appropriate.
Film evaporator is also known as mechanical stirring film evaporator, it has the advantages of ordinary evaporator can not be compared, widely used in chemical, light industry, pharmaceutical, environmental protection, food and other industries, for industrial production has brought huge economic benefits.
Optimal design of film evaporator the current situation of film evaporator product design is as follows: low work efficiency, high labor intensity, which affects the product design and development cycle.Thin film evaporator design assistant software, can greatly reduce the design calculation, improve the design efficiency, has higher engineering application value.The design is mainly to optimize the heat transfer part of the vacuum film evaporator, optimize the design of the film evaporator in terms of the heat transfer process of the material in the film evaporator and the influence of parameters on the heat transfer efficiency of the film evaporator, and improve the product quality.The temperature of the feed has a great influence on the heat transfer of the film evaporator. The film evaporator, like other evaporators, transfers heat mainly for vaporization latent heat. The feed at or near the boiling point can reasonably utilize the heat transfer area.
1. Low feed temperature.If the feed is below the boiling point under operating conditions, the considerable evaporation area is used only for preheating, reducing the heat transfer area as evaporation, since the heat transfer coefficient at preheating is much lower than that at evaporation.
2. High feed temperature can reduce the viscosity of feed liquid, which is conducive to the film distribution of feed liquid on the heating surface.When the temperature of the feed material is much higher than the boiling temperature in the evaporator, the feed liquid will produce flash evaporation. This phenomenon is more obvious in the evaporator with high vacuum, which is likely to cause foaming, or the entrainment of droplets in the secondary steam flow.
3. In the commonly used heat exchange equipment, the heat transfer coefficient of the liquid film is related to the viscosity and turbulivity on the side of the liquid wall in contact with the material.
The influence of various factors on the heat transfer coefficient
1. Influence of feed quantity.The heating surface cannot be sufficiently wetted when the feed quantity is too small, resulting in a portion of the heating surface not being utilized.
2. Influence of feed temperature.The feed liquid should be preheated to the temperature close to the boiling point. When the feed temperature is low, part of the heating surface will preheat to affect the treatment capacity.
3. Influence of heating wall material.The heat transfer coefficient of the evaporation side of the feed liquid can reach 400~1500, so the influence of the heating material on the total heat transfer coefficient cannot be ignored.Above is the main content of film evaporator optimization design.
Evaporation is one of the most important chemical unit operations. Evaporation is the process of removing water or other volatile solvents from the solution by boiling with heat. The amount of solutes in the solution remains unchanged, so that the solution is concentrated.Therefore, evaporation is a heat transfer process.There are three main evaporation operations in industrial production:
1. To improve the concentration of solute in aqueous solution.
2. To concentrate the solution and recover the solvent.
3. Prepare pure solvent by evaporation.
Evaporation can be done under pressure, atmospheric pressure and vacuum. In order to maintain the system pressure in the production process, evaporation needs to be done under pressure.For heat sensitive materials, in order to ensure product quality, evaporation and concentration at low temperature, the use of vacuum operation to reduce the boiling point of the solution.Therefore, generally no special requirements of the solution, the use of atmospheric pressure evaporation is appropriate.
Film evaporator is also known as mechanical stirring film evaporator, it has the advantages of ordinary evaporator can not be compared, widely used in chemical, light industry, pharmaceutical, environmental protection, food and other industries, for industrial production has brought huge economic benefits.
Optimal design of film evaporator the current situation of film evaporator product design is as follows: low work efficiency, high labor intensity, which affects the product design and development cycle.Thin film evaporator design assistant software, can greatly reduce the design calculation, improve the design efficiency, has higher engineering application value.The design is mainly to optimize the heat transfer part of the vacuum film evaporator, optimize the design of the film evaporator in terms of the heat transfer process of the material in the film evaporator and the influence of parameters on the heat transfer efficiency of the film evaporator, and improve the product quality.The temperature of the feed has a great influence on the heat transfer of the film evaporator. The film evaporator, like other evaporators, transfers heat mainly for vaporization latent heat. The feed at or near the boiling point can reasonably utilize the heat transfer area.
1. Low feed temperature.If the feed is below the boiling point under operating conditions, the considerable evaporation area is used only for preheating, reducing the heat transfer area as evaporation, since the heat transfer coefficient at preheating is much lower than that at evaporation.
2. High feed temperature can reduce the viscosity of feed liquid, which is conducive to the film distribution of feed liquid on the heating surface.When the temperature of the feed material is much higher than the boiling temperature in the evaporator, the feed liquid will produce flash evaporation. This phenomenon is more obvious in the evaporator with high vacuum, which is likely to cause foaming, or the entrainment of droplets in the secondary steam flow.
3. In the commonly used heat exchange equipment, the heat transfer coefficient of the liquid film is related to the viscosity and turbulivity on the side of the liquid wall in contact with the material.
The influence of various factors on the heat transfer coefficient
1. Influence of feed quantity.The heating surface cannot be sufficiently wetted when the feed quantity is too small, resulting in a portion of the heating surface not being utilized.
2. Influence of feed temperature.The feed liquid should be preheated to the temperature close to the boiling point. When the feed temperature is low, part of the heating surface will preheat to affect the treatment capacity.
3. Influence of heating wall material.The heat transfer coefficient of the evaporation side of the feed liquid can reach 400~1500, so the influence of the heating material on the total heat transfer coefficient cannot be ignored.Above is the main content of film evaporator optimization design.
