Introduction of bentonite drying technology and main drying equipment Henan Hongxing


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Introduction of bentonite drying process and main drying equipment

In the bentonite purification process, both dry process and wet process need to dry materials. Because bentonite belongs to the material with high viscosity, the selection of drying method and equipment for bentonite is very important, which directly affects the drying of materials.


1、 Drying method

Bentonite is mainly dried by direct drying method and indirect drying method. Direct drying is a drying method in which the hot flue gas contacts with bentonite directly. Indirect drying is a drying method in which the hot flue gas does not directly contact with bentonite, but transfers heat to wet clean coal through solid surface (wall).

At present, some bentonite manufacturers in China adopt direct drying method, using pure hot air generated by high-temperature heat pipe hot blast stove to dehydrate, dry and directly dry the materials; some manufacturers adopt indirect drying method, and Red Star drum dryer is an advanced indirect drying equipment in China.

2、 Drying equipment

The working principle of drum dryer: the hot flue gas is directly transported to the central fire cylinder of the dryer. At the tail of the central fire cylinder, the hot flue gas enters the plate reading channel through the connecting pipe and is discharged by the smoke exhaust hood. The wet material flow is: the flue gas is sent to the annular channel between the outer cylinder of the dryer and the central fire cylinder through the feeding pipe at the inlet end of the flue gas, which is lifted up and scattered by the board on the inner wall of the outer cylinder, and the water is evaporated under the dual effects of conduction and radiation. (see diagram).

 rattler-drying machinery

1. Characteristics of the dryer process

(1) According to the requirements of drying temperature, the central fire cylinder can be made of carbon steel and stainless steel.

(2) Several longitudinal fins can be arranged on the outer surface of the central fire tube according to the heat transfer, and the heat exchange area can be adjusted arbitrarily.

(3) The hot flue gas is isolated from the wet material, and the natural color of the material is completely maintained.

(4) Because there is no mass transfer and heat transfer process between the hot flue gas and the wet material, the waste gas discharged from the exhaust hood can be recycled, which is beneficial to reduce coal consumption and production cost.

(5) There is an expansion joint on the connecting pipe, which causes the fracture of the connecting pipe due to excessive expansion.

(6) Both sides of the exhaust hood are sealed with steel glue, so that the flue gas basically has no leakage.

2. Equipment advantages

(1) Compact structure, high efficiency, low energy consumption, simple operation, low price, economic and practical products.

(2) The inlet and outlet are equipped with front and back cover bodies, no dust, in line with the national environmental protection requirements.

(3) The equipment processing capacity is large, and the production capacity can reach the output required by different enterprises.

(4) The operation of the equipment is stable and reliable, and its service life is 5-8 years.

(5) The cost of equipment operation and maintenance is low.

3、 Trial operation conditions of drying bentonite wet materials

1. Adjust and improve the system

The material used in the trial production is bentonite with water content of about 95%. Because the bentonite expands with water and has good cohesiveness, the wet material becomes a viscous block. For the sticky and wet bentonite, the broken wing of the feeding auger does not work, but affects the feeding. Therefore, the dispersing wing is removed. Since the air volume of flue gas induced draft fan is too large to be conducive to ignition, it is easy to blow out the fire and cause danger by starting the pulse back blowing system. Therefore, the original start-up sequence is changed to ignition first, then flue gas induced air, and then pulse back blowing system.

2. Parameters and drying product index when the system is stable

The equipment is designed for continuous production for no less than 48 hours, and is mainly used for pilot test of test products. For bentonite, a wet material (about 95% moisture), after several test runs, when the system reaches balance, the main parameters are shown in Table 1, and the particle size and moisture content of dried products are shown in Table 2.

 The parameters of system stability

 Particle size and moisture content of dried products

Through the above analysis, we introduced the drying process and equipment of bentonite in detail, so that we can effectively control the drying process in the process of material purification, so as to achieve high production.

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