XI Международная студенческая научная конференция Студенческий научный форум - 2019

At the design stage of the plant for the production of milk powder, it is possible to provide such an easy way of heating the drying air as placing air intake filters inside the room where the dryer is installed. In this case, the supply air absorbs the heat emitted by the dryer and possibly by the evaporator and other equipment, especially if the air flow to the room is from above and the filters are located below, or Vice versa. The disadvantage of this method is that in the case of penetration of cold outside air and cooling, for example, cyclones, there is a danger of condensation and deposits. In addition, the supply air absorbs not only heat, but also moisture, which increases the temperature of the air at the outlet, i.e. reduces the heat capacity. If a surface air heater with a fuel oil or gas burner is used, a recuperator can be installed directly on it to transfer the heat of the combustion products to the working air [1, 2].

Combustion products usually have a temperature of > 300 °C, but their consumption is low; in addition, there is always a risk of leakage in the heat exchanger and the combustion products entering the working air. Instead, a heat exchanger with water circulation can be used. Heat exchange systems operate at the same temperature level and therefore cannot be used together.

Another way to save energy is to run the equipment needed to produce powdered milk in the correct sequence, i.e. not to turn on the spray dryer too early when the concentrate is not yet ready, because during this waiting a large amount of energy is lost. Such problems are solved by the use of computer control systems, including start-up control.

Sold milk powder must meet the requirements for the maximum moisture content, for skimmed milk powder is usually 4%. During storage, milk powder necessarily absorbs some amount of moisture, which depends on the storage conditions and packaging material. Therefore, the produced milk powder should have a lower moisture content to compensate for the absorption of moisture during storage. It is not necessary to explain that the closer the humidity of the produced product to the permissible level, the greater the energy savings, because the moisture content of the powder is directly related to the outlet temperature. That is, a higher moisture content means greater productivity per unit of energy.

Table 1. Performance parameters of the drying plant

The choice of a heat recovery system is determined by local conditions, such as the cost of steam, fuel oil and electricity. In addition, you need to consider the various interest rates on the loan. Each case requires careful calculations to develop the optimal solution that will provide the fastest payback [3].

Literature

Bezzubtsev M. M. Electrotechnology Electrotechnology and installation: a tutorial, 2012. – SPb.: Spbgau, 242 p.

Bezzubtsev M. M., Volkov V. S. , Perkin A. G., Fokin S. A. Energy technological processes study guide, 2011. – SPb.: Spbgau, 265 p.

Bezzubtsev M. M., Volkov V. S., Zubkov V. V., Applied the theory of heat and mass transfer processes in the system analysis of the energy intensity of production: – textbook, 2013. – SPb.: Spbgau, 131 p.