Method and device for drying bulk capillary-porous materials

Abstract

The present invention relates to the vacuum drying of capillary porous bulk materials, primarily grain, and can be used in agricultural, food-processing and other industries. The claimed method involves preheating of the material, its sequential loading into the vacuum drying chamber having heating elements followed by cycle-by-cycling heating of the material and vacuum creation: heating of the material in spouted bed with heat medium having temperature of up to 300°C to the material temperature which is lower than its destruction temperature, and also vacuum creation in the rapid vacuum impulse action mode with stage-by-stage single or multiple reduction of pressure in the range from 0,1 MPa to 0,0001 MPa followed by the exposure to vacuum unless the material temperature is stabilized. The said cycles are repeated unless the required material moisture is achieved. The cooling of the material is performed in the same drying chamber by alternating cooling in spouted bed and vacuum impulse action. The present drying method is implemented in the device which comprises two vacuum chambers with heaters mounted inside them, material loading / unloading system, one or several receivers with pumps connected in parallel to them and connected via vacuum pipeline system with quick-acting valves to the drying chamber inlet. The said vacuum drying chambers are cone-shaped at their bases, connected to the heat medium circulation system for spouted bed heating and cooling of the material and have heating jackets. The heat medium vacuum treatment and circulation lines are equipped with heated cyclone filters and heat exchangers-condensers with condensate tanks. The present invention helps both to reduce drying time required for the material, primarily grain, and to increase quality of the dried product.

Description

Technical field [0001] The present invention relates to the vacuum drying of materials with large pores and large pores (mainly grains), which can be applied to agriculture, food industry, wood processing industry, chemistry and other industries. Background technique [0002] Known methods for drying pores and a large number of materials (including grains) usually use preheated dry air under fluidized conditions to contact the materials to be dried to achieve the purpose of removing wet mist (application RF N93028584, MPK, classification number: F26B17 / 10). [0003] The disadvantages of this method are due to the high consumption of the drying medium and the low process economy, and it is difficult to organize the heating temperature and exposure time of the material separated particles in the reaction zone that affects both the drying time of the material and the amount of material to be dried. control. [0004] Known methods for vacuum drying of pores and large amounts of materia...

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Problems solved by technology

[0009] The disadvantage of this method is that the drying process is carried out under equilibrium conditions which are at low pressure and which both complicates the sharing of thermal energy to the material and increases the drying time

Furthermore, the design of the device to implement the method is complex and entails considerable material costs for non-standard devices, including control systems

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