SU1201638A1 - Method of automatic control of spray drying process - Google Patents

Description

The invention relates to a process control technique for spray drying and may find application in various industries.

The purpose of the invention is to improve the accuracy of regulation.

FIG. 1 shows a block diagram of an installation for implementing this method; in fig. 2 - a device for measuring the moisture content of the dried product by friction force.

The installation contains spray drying 1, regulators stabilize the temperature of the spent drying agent 2 and the vacuum in the drying volume 3, temperature sensors spent 4 drying agent and the temperature of the fresh 5 drying agent, the sensor 6 temperature of the finished product, block 7 determine the coefficients of friction of the finished product, sensor 8 flow source material, the sensor 9 dilution, the actuator 10 changes the supply of fresh drying agent, the actuator 11 changes the exhaust exhaust drying agent. Unit 7 has a fixed bracket 12, the spring 13, the plate 14 and the Converter 15 stretching the spring into a unified signal.

The installation works as follows.

From the sensor 4, the temperature of the spent drying agent signal goes to the controller 2, which stabilizes the temperature of the exhaust gases at the outlet of the dryer by changing the supply of fresh agent. When changing the flow rate of the source material from the sensor 8 to the controller 2 receives a correction signal to compensate for the effect of changes in the flow rate of the source material. The finished product (yeast) from the dryer 1 in the form of powder is fed to a conveyor belt, which moves at a constant speed. The quality of the yeast obtained is estimated by the index of friction, which characterizes the moisture content of the finished product, and the shape of the dried particles. The coefficient of friction of the finished product is continuously determined by block 7. The operation of block 7 is as follows. On fixed bracket 12,

made of a magnetostrictive material, a spring 13 is fastened, on which a plastic plate 14 of a given weight is freely suspended. The plate 14 freely lies on the surface of the finished product moving at a constant speed along with the conveyor belt. When the product quality changes, i.e. basically the change in humidity, the tension of the spring 13 changes, which characterizes the magnitude of the friction coefficient.

The tension spring 13 causes an electrical signal proportional to the bracket 12 made of a magnetostrictive material, then this signal is cut Th ₁₅ converter 15 is converted into a unified signal.

To obtain good quality fodder yeast, it is necessary to keep the friction coefficient at a certain level. To stabilize the magnitude of the friction coefficient, the regulator 2 is fed a correction signal from the transducer 15 for a corresponding change in the supply of fresh drying agent.

In addition, the quality of the drying process is affected by the vacuum at the outlet of the dryer, ²⁵ which determines the aerodynamic regime

inside the dryer. In order to stabilize the aerodynamic mode, the sensor 9 measures the vacuum in the drying volume and a signal is sent to the controller 3, which,

_{30 by} changing the exhaust gas suction, regulates the vacuum in the dryer.

The set value of vacuum is corrected by applying correction signals to the controller 3 from the sensor 5 of the temperature of the fresh drying agent and the sensor 6 of the temperature of the finished product. The stabilization of the temperature of the finished product is due to the fact that this parameter is correlated with the coefficient of friction of the finished product, as well as with the nature

aerodynamic regime in the dryer.

40 The invention improves the accuracy

control the spray drying process, improve the quality of the product and reduce the loss of fodder yeast from the release along with the exhaust gases.

Claims (2)

METHOD OF AUTOMATIC CONTROL OF THE SPRAY DRYING PROCESS by measuring the temperature of fresh and spent drying agent, raw material consumption and changing the drying agent consumption by the temperature of the spent drying agent and raw material consumption, characterized in that, to improve the control accuracy, the coefficient of friction is additionally measured the temperature of the finished product, the vacuum in the drying volume and additionally regulate the amount of spent drying agent, depending of the amount of vacuum in the drying volume, the temperature of the finished product and the temperature of the spent drying agent, and the change in the flow rate of the drying agent is adjusted according to the coefficient of friction of the finished product. 5 and „„ 1201638 FIG. / 2 one 1201638