Method and device for material drying by means of porous media

Abstract

The invention discloses a method and device for drying materials by using porous media, which adopts a countercurrent method to dry materials, and the materials to be dried in the drying bin and the porous media are mixed into the first drying layer and come from the second drying layer in the distribution bin. The hot air fully contacts the heat exchange, absorbs heat, and evaporates the water to dry the material; the waste hot air passing through the first drying layer is discharged from the drying chamber; the mixture of the material and the porous medium passing through the first drying layer enters the screen device, and passes through After sieving, the material is separated from the porous medium, and the porous medium returns to the distribution bin to mix with the material to be dried; the material passing through the first drying layer enters the second drying layer and contacts with the hot air from the third drying layer to exchange heat, and in the third drying layer Contact with hot air to exchange heat, and when the final moisture content requirement is reached, it will be transported out of the drying bin. The invention especially solves the problem of drying viscous materials, and its drying method and equipment are relatively simple, which can realize high efficiency and energy saving in the material drying process.

Description

technical field [0001] The invention relates to a method and device for drying viscous materials, in particular to a method and device for realizing material drying by using porous media. Background technique [0002] According to statistics, drying energy consumption accounts for about 30% of the total energy consumption of the national economy, especially viscous materials such as municipal or chemical sludge, which have high viscosity, long drying cycle and high heat consumption. At present, most of them use high-temperature flue gas generated by fuel combustion as a heat source to dry materials. This method not only requires large investment and high cost, but also causes environmental pollution. Another way is to use the method of drying in a solar greenhouse, which takes a long time to dry. If it is combined with other heat sources for drying, the space will be larger and the heat loss will be serious. For different types of materials, when the moisture content of the...

AI Technical Summary

Problems solved by technology

At present, most of the high-temperature flue gas generated by fuel combustion is used as a heat source to dry materials. This method not only requires a large investment and high cost, but also causes environmental pollution.

Another way is to use the method of drying in a solar greenhouse, which takes a long time to dry. If it is combined with other heat sources for drying, the space will be larger and the heat loss will be serious.

For different types of materials, when the moisture content of the material is higher than a certain value, even after reverse mixing, it cannot effectively avoid its adhesion on the surface of the turning device. At this time, the wet material is wrapped on the surface of the dry material and sticks into large groups, resulting in turning over. The throwing machine can't play the role of turning and throwing, which seriously affects the drying effect of the material

Secondly, for materials with very small particle size, the bulk density is relatively high and the surface pores are few, resulting in a small contact surface area with hot air, which cannot achieve sufficient contact between hot air and materials, which affects the effect of convective heat transfer

Furthermore, air is generally used as the main drying medium, and air has a small specific heat capacity and has no heat storage capacity, resulting in poor drying effect in a large space.

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