Manihot esculenta Crantz, a perennial tropical crop, was introduced into China in the 1920s and is now widely distributed in south China regions such as guangxi, guangdong, fujian, yunnan, jiangxi, sichuan, guizhou and hainan.Cassava is mainly used for food, feed and industry. About 65% of fresh potatoes are used for food in the world, while 90% of fresh potatoes in China are used for industrial processing of high value products such as starch, modified starch and alcohol.

This section focuses on the process and equipment of fresh cassava root processing cassava starch.

At present, the standard of fresh cassava starch processing plant, the process must include raw material removing impurity cleaning unit, raw material crushing unit, starch extraction unit, refined starch concentration, starch, starch dehydration units dry packing unit, waste water treatment unit and control system for unit 8 units, such as its main process can be summarized as four process, including: clean fresh potato peeling, crushing, screening enrichment and dry packaging process, the specific process as shown in figure 

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I. cleaning and peeling process

Cleaning and peeling is the first step of tapioca starch processing process, mainly to remove the fresh potato surface sediment, potato block surface.Horizontal cage cleaning machine and blade cleaning machine are commonly used in cleaning and peeling process

1- fresh cassava tubers are sent to the horizontal squirrel cage washing machine to clean the sediment;

2- the horizontal squirrel cage washing machine rotates under the drive of the motor, and the fresh potato moves forward along the axis;

3- fresh potatoes will be removed from the horizontal squirrel cage cleaning machine, and then enter into the cleaning machine.

4- remove the fresh skin by rubbing against each other under the action of stirring paddle in the pulp and leaf cleaning tank;

5- after washing, the potato blocks enter the crushing process through the conveyor belt, while the washing water can be recycled for recycling.

Second, crushing extraction process

Starch is stored in root cells and can be obtained by crushing potato pieces.Crushing is the operation process of crushing large solid materials into suitable or fine powder with the help of external force.There are many kinds of mill, such as disc mill, hammer mill, turbine mill and file mill.

(1) disc crusher

Disc crusher, also known as air-flow disc crusher, its working principle is: through the crushing room nozzle compressed air to form the airflow beam, so that the mutual collision between materials, friction and material and chamber wall, impact plate collision, friction and achieve the purpose of crushing.

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FIG. 4. Disc crusher

Saw - type file grinding mill

The working principle of sawing file grinding machine is that the materials stored in the storage bucket enter the file disc above the body of the file grinding machine through the transfer machine, and the file disc rotates in a high speed circle to crush the materials above, and then take the crushed materials out of the file grinding machine through rotation.