SU800545A1 - Fluidised-bed dryer for loose materials - Google Patents

Description

(54) BOOT LAYER DRYER FOR BULK MATS ALOVE

The invention relates to a device for drying with stirring a material to be dried by means of a flow of a gaseous medium. Fluid bed dryers for volatile materials are known, comprising a drying chamber with a gas distribution grill and a heat exchanger placed in the bed with supply and discharge pipes, mounted on hangers and oscillating with a vibration drive. Known dryers can increase productivity, reduce dust and improve hydr dynamics 1. However, known dryers are characterized by constructive complexity. The closest to the technical essence of the present invention are fluidized bed dryers for bulk materials containing a drying chamber with a gas distribution grid and a heat exchanger in the form of heating elements. In this design, the heat exchanger nozzles are brought out through the same chamber wall, for example, face and rigidly connected to a vibratory actuator, made two-shaft, the shafts of which are placed in the vertical plane 2. The drawbacks of such dryers are as follows: design complexity therefore, an increase in its overall dimensions, a low efficiency of about 15–20% due to the need to heat the coolant in a special device and feed it to the heat exchanger, as well as low heat transfer coefficient between the walls of the heat exchanger and the fluidized bed. Heat transfer -.in known dryer occurs from the heat exchanger to the material to be dried at the contact of the latter with the walls of the heat exchanger. The feed gas through the gas distribution grid serves only to create a fluid bed of the material to be dried. At the same time, the gas takes a significant part of the heat and carries it away without transferring it to the material being dried. In addition, the drying takes a relatively long time, since it depends on the temperature of the heat transfer medium and, therefore, the temperature of the walls of the heat exchanger, as well as on the surface area of the latter.

To reduce the drying time, it is necessary to increase either the temperature of the heat transfer medium or the surface area of the heat exchanger, which. complicates the drying process and the design itself.

The purpose of the invention is to increase thermal efficiency.

This goal is achieved by the fact that the gas distribution grid is filled in the form of a layer of highly heat-conducting porous material in which the heating elements of the heat exchanger are evenly distributed. With this design, the heating elements heat a layer of porous, highly heat-conducting material. The gas passing through the pores of this material is heated. In this case, it serves not only to create a fluidized bed, but also as an agent that transfers heat to the material being dried. The passage through the layer of material being dried, the gas completely gives it its heat and practically goes into the atmosphere cold.

Studies show that: heat exchange between hot air and particles occurs in the near-lattice zone with a height of no more than 100 mm.

The drawing shows schematically the proposed dryer.

The dryer contains a drying chamber 1, a gas distribution grid 2 of highly heat-conducting porous material with heat exchanger heating elements 3 placed in it, a duct 4 for supplying compressed air, a nozzle 5 for air outlet a loading device 6 for a dried material, a nozzle 7 for unloading dry material.

The dryer works as follows.

The material being dried is fed into the drying chamber 1 using a loading device b, and the dry product is taken out through the nozzle 7. Compressed

the air from the duct 4 passes through the gas distribution grid 2 with the heating elements 3, heats up, forms a fluidized bed and is removed from the drying chamber through the nozzle 5.

5, in the proposed dryer, the zone of possible heat exchange is significantly expanded and practically spreads over the entire layer of the material being dried, which creates favorable

conditions for complete transfer of heat from the gas to the material being dried. The drying rate is greatly increased. : In addition, the dryer described above eliminates the need for

5 vibrodrive that simplifies the design, reduces the size, simplifies and reduces the cost of maintenance of the dryer.

As heating elements Elements can be used

Q with coolant or tubular electric heating elements.

The economic effect of the introduction of the dryer can be obtained by reducing the consumption of its manufacture, installation, operation, repair and

service-.

Claims (2)

1. USSR author's certificate number 434241, cl. f 26 B 17/10, 1971. 2. USSR author's certificate number 491807, cl. F 26 B 17/10, 1974. five / lU. about oh oh oh l , 01 “r and o about. and a oh oh , 0 o l o v