Advanced cassava processing technology

Can Jiangsu Lianhai Biology not produce those 200,000 tons of cassava butanol? Go and take a look!

What products do you produce? If it’s ethanol, COFCO has a company in Guangxi that produces fuel ethanol. The technology is relatively mature. Can be used as a reference

It seems that the technology isn’t yet fully developed and requires further improvement; otherwise, the project would have been implemented nationwide

Technology isn’t the big issue; it’s mainly the raw materials

The price of raw materials for dried cassava sheets is still quite high, making it not very cost-effective whether to use them for alcohol or starch production.

At present, the production volume of such factories fails to meet the required standards, due to constraints imposed by raw materials and the market.

Hehe, I know. We are also a member company of COFCO Group; they are our sister companies!

Cassava for starch production 1 Overview: Cassava starch is primarily used as a raw material in various industrial sectors such as food manufacturing, sugar production, pharmaceuticals, feed production, textiles, papermaking, and the chemical industry. The production process of cassava starch is a physical separation process, which involves separating the starch in the cassava raw material from other substances such as cellulose, proteins, and inorganic compounds. During the production process, taking advantage of the fact that starch is insoluble in cold water and has a density greater than that of water, water and specialized mechanical equipment are used to separate the starch from its aqueous suspension, thereby achieving the recovery of starch. Its production process includes steps such as conveying, cleaning, crushing, impregnation, screening, bleaching, desanding, separation, dehydration, drying, air cooling, and packaging. 2 Raw materials: The raw materials for cassava starch include fresh cassava and dried cassava slices; these are the main substances used in production. It is essential to ensure their quality – fresh cassava should be purchased on the same day it is brought to the factory, processed on the same day, and must not contain any mud, sand, roots, fibers, wooden parts, or other impurities ； Cassava chips should be dry, free from mold, deterioration, and insect damage. The average composition of fresh cassava is as follows: starch 27%, cellulose 4%, protein 1%, others 3%, and moisture 65%. The average composition of dried cassava flakes is: starch 68%, cellulose 8%, protein 3%, others 8%, and moisture 13%. 3. Additives: (used in the processing of dried cassava flakes to produce starch) sulfuric acid 2 KG/T of starch, bleaching powder 0.5 kg/T of starch, potassium permanganate 0.1 kg/T of starch. 4. Processing route: The wet processing method for cassava starch involves drum washing, secondary crushing, thick slurry screening, counter-current washing, oxidation-reduction bleaching (only necessary when using fresh cassava as raw material), centrifugal sand removal, thick slurry separation, dehydration by overflow method, and primary negative-pressure pulse air drying. 5 Process flow (omitted) 6 Main process steps: (1) Raw material preparation; (2) Raw material transportation. A cassava collector and conveyor are used to transport cassava from the storage area to the washing machine. (3) Cleaning: A GX-850 type drum washer is used, which consists of a rough cleaning area, a rinsing area, and a final cleaning area. The cassava raw material moves forward as it rolls along the wall of the cylinder; water is used as a medium (with a water-to-cassava ratio of 1:4) to spray, rinse, wash, grind, clean, and peel it. It is required that the sediment be removed through cleaning to achieve a peeling rate of over 80%, before it is sent to the crushing process. (4) Disintegration: The function of disintegration is to break down the organizational structure of cassava, thereby allowing the tiny starch particles to be released and separated from the cassava tubers. A 6wsJ-45 type pendulum hammer crusher is used. This machine relies on high-speed operation to cause the hammer heads to fly and, together with the hammer edges, partition plates, and screening plates, to pound, file, cut, and compress the continuously fed cassava, thereby breaking it down. This process allows starch particles to separate out, and using water as a medium (with a water-to-cassava ratio of 1:1), the crushed cassava is processed into starch slurry. The secondary crushing process is currently widely used to achieve a more thorough and fine breakdown of the cassava tissue, enabling a more complete separation of starch particles, which is beneficial for improving the extraction rate. The starch slurry after the first disruption is required to pass through sieve pores of about 8.0 mm, while the starch slurry after the second disruption must pass through sieve pores of 1.2–1.4 mm. (5) Mixing Mixing is an essential step in processes such as crushing, screening, bleaching, desanding, separation, and dewatering. Its function is to store the protoplasm and milk serum ； Balanced emulsion concentration ； Adjust the pH of the milk slurry to facilitate starch separation ； Avoid starch precipitation, etc. (6) Screening: The diluted starch slurry obtained after crushing and mixing must be screened in order to separate the starch milk from the fibers. At the same time, starch milk needs to be screened to remove fine residues, and fibers require detergent recovery of starch. Screening is used to achieve the separation and purification of starch. Currently, 120-pressure curved screen sieves and vertical centrifugal sieves are primarily used; these two types are employed together, with the curved screen sieves being used for sorting and washing the fibers, while the vertical centrifugal sieves are used for further refining to remove fine residues. Multiple screening or counter-current washing processes are commonly employed. It is required that through primary screening and washing, the starch content in the potato residue (on a dry basis) be below 35%, with the free starch content being less than 5% ； The fiber impurity content in the milk serum is below 0.05% ； The emulsion concentration reaches 5–6 Bé. (7) Bleaching is an important step in ensuring the quality of starch products made from dried cassava sheets. Its function is to regulate the pH of the milk serum in order to control microbial activity as well as fermentation and saccharification ； Accelerate the separation of starch from other impurities ； It removes the gelatinous layer from the outer surface of starch particles, keeping them permanently white. (8) Sand removal: Based on the principle of separation by specific gravity, the starch slurry is pumped into a swirl using a pressure pump; sand is removed from the bottom stream while the slurry passes through the top stream, thereby achieving sand removal. Sand removal not only eliminates impurities such as fine sand but also protects the disc separator. (9) The function of separation is to remove insoluble proteins, residual soluble proteins, and other impurities from the starch slurry, thereby achieving the purposes of washing, refining, and concentrating the starch slurry. Currently, disk separators are widely used to wash, refine, and concentrate starch slurries. It separates based on the different specific gravities of water, starch, and xanthan gum. Generally, two disc separators are used in series, with the required pulp concentration at the first stage being 5–6 Bé, and the pulp concentration at the output stage being 20–22 Bé. (10) Dewatering: The concentrated slurry still contains a large amount of water after the separation process, so dewatering is necessary to facilitate drying. Currently, scraper centrifuges are commonly used for dewatering by the slurry overflow method. It is required that the moisture content of the wet starch after dehydration be below 38%. (11) Drying: The wet starch dehydrated by a scraper centrifuge is transported to an air-flow dryer for drying. The steam pressure is controlled at 0.8 Mpa. Drying is required so that the moisture content of the finished starch product is around 13.5%. (12) Pack and store in inventory.

Processing cassava is not difficult in itself; the key is to choose the right equipment. We are currently using corn processing equipment to process cassava, and this results in frequent clogging and damage of the equipment, as well as inaccurate measurement

The processing techniques for cassava are basically the same as those for potatoes and sweet potatoes; research on these latter two has been going on for a long time