How to better choose spray dryer in food industry
In the food industry, spray drying equipment is a contradiction. It can not only maintain the appearance and original nutritional value of food, but also produce coffee mate, egg yolk powder, milk powder, soup, juice powder and other products. Such as large power consumption, large volume, easy to stick to the wall, large one-time investment and other defects. Under the heavy pressure of national environmental protection and the increasing demand for food, spray drying equipment must maintain its status and need more work.
The spray drying equipment can be divided into centrifugal, pressure and airflow according to the structure of atomizer. Spray dried foods can be solutions, grout or paste, but they must be pumped. Food materials need to be atomized before heat exchange in the drying chamber. Because the droplets formed by spray are very small, they provide considerable heat exchange area and make the evaporation process fast.
(I)The phenomenon of sticking to the wall has become the primary problem
Wall adhesion is a serious problem, which hinders the normal operation of Spray Dryer. Foods rich in animal fat tend to deposit on the walls of the drying chamber. With the passage of time, these food raw materials will gradually evolve into pollution sources and endanger food health. Therefore, many spray dryer manufacturers and experts and scholars have studied some solutions to solve the problem of sticking to the wall. They think this is because the wall temperature of the spray dryer is too high to make the product sticky. Therefore, the drying chamber is changed into sandwich structure to improve the cooling efficiency. Objects such as vibrators and air hammers are used to separate adherent walls. The tangential introduction of secondary air cooling tower wall; the bottom of drying chamber wall is often polished with conical bottom to reduce the possibility of material retention. Some companies have added new technologies such as anti stick sweeping wall
(II) placement problem of over volume
Restricted placement area with excessive volume. Pay attention to food production conditions, many food companies have set up 300000 or 100000 dust-free purification workshop, but because of the larger size of spray dryer, they can not be placed in the entire clean area. Some of the materials collected by many companies will be selected to be placed in clean areas and the rest will be placed elsewhere. In view of this situation, the spray drying equipment system needs to improve the sealing performance and prevent the external environmental pollution.
(III) Material control can be changed to intelligent
Spray dryer needs particle size distribution, residual moisture content in finished products, bulk density and particle shape can meet the precise standard during operation. The particles produced can achieve the desired effect. Taking bulk density as an example, bulk density is one of the important characteristics of food in spray drying process. Every measure must ensure the best packing density during operation. The bulk density of impact is related to powder temperature and humidity, feed temperature, particle size distribution, inhaling dry air temperature, product discharge temperature, air contact method, sprayer type and location in spray dryer. In order to ensure the ideal packing density of food raw materials, experienced teachers are needed to sit down. However, with the advent of the chemical age, the spray dryer can greatly reduce the dependence on the human body by analyzing and judging the spray temperature and duration needed by the spray dryer according to the humidity, location and particle size of the material.
(IV)Solving the problems of environmental protection and energy saving is the top priority
Although there is no dust in the process of spray drying, it is easy to produce dust at the outlet of the product. In addition, the application rate of low heat efficiency of spray drying equipment is an indisputable fact. Usually, the entrance temperature is about 150 degrees C to 250 degrees C, and the outlet temperature after spray drying is 60 degrees C to 100 degrees C. It can be seen that most of the heat energy is not utilized. At present, some enterprises have adopted cyclone separator to solve the problem of dust and waste heat recovery device, in order to solve the problem of low thermal efficiency. However, the results are not satisfactory. It can be seen that spray drying equipment needs to increase R & D efforts on the road of energy saving and environmental protection and continue to move forward.
To sum up, the application of spray drying in food industry not only overcomes the shortcomings of difficult storage of materials, preserves the nutritional value of materials, but also simplifies the production process and avoids the problem of dust in the drying process.
With the in-depth research and development of spray drying technology and equipment, more and more spray drying equipment will appear in the market. The food industry will accelerate its development and has broad prospects.
