RU2303212C1 - Method and device for drying thermostable solutions - Google Patents

Abstract

FIELD: drying engineering.

SUBSTANCE: method comprises supplying initial solution to the top section of the drying chamber by means of nozzles and supplying preliminary heated drying agent through the bottom section of the drying chamber at a pressure up to 15 MPa. The solution is heated up to a temperature that is lower than the boiling temperature by several degrees. The device comprises drying chamber with nozzles, collector for supplying drying agent, high-pressure pump that pumps the solution through the heat exchanger, and three nozzles arranged in the diametrical plane of the top conical section of the drying chamber. The angle between the axes of the jets ranges from 60 to 120°. The high-temperature furnace gases flow from the furnace to the heat exchanger and then to the collector in the bottom section of the drying chamber. The top section of the drying chamber is provided with the branch pipe for discharging exhaust gases. The bottom section of the drying chamber is provided with the screw device for discharging the finished product.

EFFECT: enhanced efficiency.

2 cl, 1 dwg

Description

The invention relates to techniques for drying dispersed materials and can be used in microbiological, food, chemical and other industries.

The closest technical solution to the claimed object is a dryer by.with. USSR No. 553424, F26В 17/10, 1975, containing a drying chamber with nozzles and a collector for supplying a drying agent (prototype).

The disadvantage of the prototype is the relatively low productivity of drying the final product.

The technical result is an increase in drying performance.

This is achieved by the fact that in the method of drying heat-resistant solutions, which consists in the fact that the initial solution is supplied to the upper part of the drying chamber by means of nozzles, and the drying agent is supplied countercurrently through the lower part of the drying chamber; to intensify the spray drying process, the solution is supplied with preliminary overheating at a pressure of up to 15 MPa, and the solution is overheated to a temperature that is several degrees lower than its boiling point at a given pressure, in order to avoid the formation of a two-phase system in heat transfer pipes.

This is achieved by the fact that in the device for drying heat-resistant solutions containing a drying chamber with nozzles and a collector for supplying a drying agent, an additional high-pressure pump is installed that pumps the solution in the tank through the heat exchanger into at least three nozzles located in the diametrical plane of the upper conical part of the drying chamber, and the direction of the jets of the nozzles is cross with the angle between the axes of the jets lying in the optimal range of values: 60 ... 120 degrees, and in yc exchanger of the high temperature furnace flue gases are fed to a collector, situated in the lower part of the drying chamber and in the upper part of the drying chamber is located nozzle for exit of the exhaust gas and at the bottom a screw device for discharging the finished product.

The drawing shows a General view of a dryer for implementing the proposed method.

The dryer for heat-resistant solutions located in the tank 6 contains a high pressure pump 1, which pumps the solution through the heat exchanger 3 into at least three nozzles 4 located in the diametrical plane of the upper conical part 13 of the drying chamber 5. The direction of the jets of the nozzles 4 is chosen cross , with an angle between the axes of the jets lying in the optimal range of values: 60 ... 120 degrees.

The heat exchanger 3 from the furnace 2 receives high-temperature flue gases into the collector 7 located in the lower part of the drying chamber 5. Fuel is supplied to the furnace 2 through the line 8, and air enters through the line 9 through the blower 10. In the upper part of the drying chamber 5 there is a pipe 11 for exhaust gas, and in the lower part a screw device 12 for unloading the finished product.

To intensify the drying process, ultrasonic nozzles with a half-wave magnetostrictive transducer equipped with an exponential concentrator with a resonant frequency of oscillations lying in the range from 20 to 60 kHz (not shown) can be used.

A dryer for heat-resistant solutions works as follows.

For heat-resistant solutions, the intensification of the spray drying process is achieved by preheating the solutions. According to this method, a true solution at a pressure of up to 15 MPa is overheated to a temperature that is several degrees lower than its boiling point at a given pressure, in order to avoid the formation of a two-phase system in heat transfer pipes. When the superheated solution exits the nozzle of the nozzle, boiling of dispersed droplets occurs with evaporation of moisture due to accumulated heat.

The solution is pumped by a high pressure pump 1 through a heat exchanger 3, installed at the outlet of the furnace 2, and fed into the spray drying chamber 5, where it is dispersed by nozzles 4 and dried in a stream of recycled flue gases leaving the heat exchanger. The dryer works according to the counterflow scheme.

Preliminary use of the heat of the flue gases in the heat exchanger eliminates the need to dilute them with cold air, which increases the exergy efficiency of the installation at the same temperature of the exhaust gases. When the unit operates on the principle of counterflow, it is possible to significantly increase the humidity of the exhaust gases. The voltage of the chamber through evaporated moisture increases by an amount equal to the amount of moisture evaporating as a result of self-boiling. The finished product is obtained finely dispersed and uniform in particle size.

Claims (3)

1. The method of drying heat-resistant solutions, which consists in the fact that the initial solution is fed into the upper part of the drying chamber by means of nozzles, and the drying agent is supplied countercurrently through the lower part of the drying chamber, characterized in that to intensify the spray drying process, the solution is supplied under preliminary heating at a pressure up to 15 MPa, and the solution is overheated to a temperature that is several degrees lower than its boiling point at a given pressure in order to avoid the formation of a two-phase system in heat exchange pipes. 2. A dryer for heat-resistant solutions containing a drying chamber with nozzles and a collector for supplying a drying agent, characterized in that it contains a high-pressure pump that pumps the solution in the tank through the heat exchanger into at least three nozzles located in the diametrical plane of the upper conical part of the drying chamber, and the direction of the jets of the nozzles is cross with the angle between the axes of the jets lying in the optimal range of 60-120 °, and the heat exchanger enters the body of the heat exchanger high temperature flue gases out into the reservoir, located at the bottom of the drying chamber and in the upper part of the drying chamber is located nozzle for exit of the exhaust gas while the lower part - screw device for discharging the finished product. 3. The dryer for heat-resistant solutions according to claim 2, characterized in that the nozzles are ultrasonic with a half-wave magnetostrictive transducer and an exponential concentrator with a resonant frequency of oscillation lying in the range from 20 to 60 kHz.