SU800532A1 - Liquid material drying method - Google Patents

Description

(54) METHOD FOR DRYING LIQUID MATERIALS

The invention relates to a drying technique, to methods for drying liquid products, such as medical preparations, and can be used for drying a wide class of materials used in the chemical, chemical, pharmaceutical, biological, and other industries. There are known methods for drying liquid materials, which consist in preheating the solution to a temperature below the boiling point at high pressure in a surface heat exchanger washed by hot gases from the combustion device, after which the solution is injected through the nozzle into the chamber with reduced pressure. where most of the moisture is converted into steam, used for final drying of solid wet material in a second-stage dryer or pre-evaporation of a solution in a multi-unit max. However, the application of a furnace with a surface-type heat exchanger, a pump for feeding the solution through a heat exchanger to the spray nozzles with a reduced pressure, and a second stage dryer with rotating plates requires complicated equipment that makes it difficult to regulate the process. In addition, this method is characterized by a low intensity of heat transfer when the solution is heated in surface heat exchangers. The closest in technical essence to the proposed methods of drying liquid materials by preheating them in surface heat exchangers and spraying into a boiling bed 2. The disadvantages of the known methods are the necessity to create a large pressure, the organization of the drying process in two or more separate chambers and the impossibility of using it for thermolabile materials; The purpose of the invention is to intensify the drying process. This goal is achieved by preheating the liquid material to a temperature of 50-70 seconds by direct contact with hot air and then transporting it to a boiling bed at a temperature of 5-10 ° C below the melting point of the material.

The drawing schematically shows the installation, working on the proposed method.

The installation comprises a tank 1, a pump 2. For supplying the solution, a compressor 3 for supplying air through the heater 4 to the pipe 5, where the air is in contact with the solution during transport. The installation also contains a fluidized bed dryer 6 with a nozzle annular manifold 7 for spraying a hot solution. The dryer is equipped with a cyclone 8, a filter 9 and a fan 10, it also has an air preheater 11, a diffuser 12 and a discharge device 13.

The installation works as follows.

The solution or suspension to be dried is heated to 2535 ° E in tank 1, then pump 2 is fed to pipe 5, into which hot air is pumped to the edge of compressor 3. In this pipe 5, the solution in the mode of pneumatic transport is heated with hot air up to 50-70-C. Air is heated in preheater 4. A hot solution through an annular nozzle manifold 7 is blown into a fluidized bed dryer, into which coolant is fed through a diffuser 12 from preheater 11. The dry material is continuously discharged from the discharge device 13, and the exhaust air through the cyclone 8 and the filter 9 is removed by the fan 10 to the atmosphere.

Preheating of the solution allows treating thermolabile materials in a fluidized bed at elevated temperatures of the fluidized bed

 below the melting point), since in this case there is no abrupt increase in the temperature of the material when injected into the fluidized bed and the drying process takes place under mild conditions without changing the quality of the material. The implementation of preheating of liquid materials by direct contact (mixing) with hot air allows to obtain higher values of the heat transfer coefficient from gas to liquid, which leads to an intensification of heat exchange, and hence a decrease in size. So drying can occur in a single-chamber apparatus without the use of high pressure.

Claims (2)

1. USSR author's certificate number 116854, cl. F 26 B 3/12, 1958. 2. USSR author's certificate number 153237, cl. F 26 B 3/12, 1962.