In recent years and potato starch, wheat starch, and corn starch, tapioca starch has become more popular. Tapioca starch is extracted from the cassava root. The cassava plant is a tropical root crop, mainly grown in Asia, Africa, and South America. Tapioca starch does not contain gluten, protein and fat, and is almost 100% composed of carbohydrates. It is mainly used as raw materials for food, sugar, medicine, feed, textile, paper, chemical, and other industrial sectors.
Tapioca starch production process is a physical separation process. The starch in the cassava raw material is separated from other substances such as cellulose, white, and inorganic. In the tapioca starch process, based on the nature that starch is insoluble in cold water and has greater specific gravity than water, special mechanical equipment is used to separate starch from the water suspension to achieve its purpose of recovering starch. The production process is divided into conveying, cleaning, disintegrating, dipping, screening, bleaching, desanding, separation, dehydration, dry bath, air cooling, packaging, and other processes.
The prerequisites for using a decanter for tapioca starch production are:
The operation must be done in liquid
There must be a density difference between the components of the material to be separated. The greater the density difference, the easier the separation.
The particles of the solid material to be separated can form a suspension in the liquid.
Tapioca starch is insoluble in cold water; therefore, water is used as an auxiliary medium to form a suspension of materials to be separated. Thus, water is used as an additional medium to create a suspension of the materials to be separated. A decanter centrifuge can separate starch and protein of different densities or separate starch groups of different densities, or separate water-insoluble starch and protein from the suspension.
Specifically, there are three aspects:
The wastewater produced in tapioca starch production contains small solid particles and high viscosity. The filtration method is very inefficient or even challenging to work with. For wastewater with a concentration greater than 5%, a decanter centrifuge can be used directly for concentration and dehydration, and the dry material is recovered. If the concentration is too low, it can be used in conjunction with a disc centrifuge. First, use a disc centrifuge for pre-concentration, and then use a decanter centrifuge for concentration and dehydration.
The efficiency of mechanical dehydration is 5 to 10 times higher than evaporation (heat, freezing, etc.). If the solid particles contained in the thick slurry are small, the viscosity will be relatively large. The filtration and dehydration method is inefficient and has a relatively high solid water content. The decanter centrifuge can be operated continuously without washing and has a large output.
In the modern starch production process, the decanter centrifuge has been widely used as an efficient and continuous operation separation equipment, especially in tapioca starch production process, including the latest three-phase decanter centrifuge and double cone decanter centrifuge have been adopted.