Corn Starch Processing Line

Corn is one of the main crops in the world and the main raw material for making starch. Corn starch can not only be eaten directly, but also an important industrial raw material, widely used in starch sugar, food processing, medicine, textile, chemical and other industries.
Huatai can provide you with medium and large corn starch production equipment, and provide a series of complete solutions for domestic and foreign customers from market research to product selection, factory design, equipment matching, installation and commissioning production and packaging design. At the same time, we sell all kinds of related machine equipment: cyclone screen, air dryer, separator, etc.

Maize starch unit

The production of maize starch will include the following operations, such as raw maize cleaning, preparation of sulfureous acid as steeping liquid, maize steeping, germ separating and drying, fiber separating and drying, gluten separating & drying and starch washing, starch drying.

 Maize cleaning:

The raw maize will be transported by trucks to the plant where it is metered through the truck platform weigher and used as raw material for production of maize starch. First the impurities, such as stones, iron foreign material and others, will be removed from it by the maize cleaning screen and the magnetic separator. Then it is conveyed and fed into the maize storage silos through the elevator and the apron conveyor.  

Preparation of sulfureous acid:

Sulfureous acid is used as the steeping liquid in the maize steeping. Sulfur is quantitatively fed into the sulfur-burning furnace where it burns to form SO2 gas. SO2 gas flows into the SO2 absorbing column, within it SO2 gas is absorbed with water to form sulfureous acid with specified concentration. Sulfureous acid will store in the acid storage tank, from which it is fed by pump into the steeping tanks as steeping liquid. The tail gas coming from the SO2 absorbing column will be vented to air by the tail gas fan.

Maize steeping:

The maize in the silos is quantitatively fed by the electronic weigher from the silo into the hydro-feeding trough, by which the maize comes into the feed tank where some heavy impurities will settle down by gravity difference and separated out from maize. Then the maize-water slurry is pumped to steeping tanks.

For steeping the liquid is fully discharged out from the maize-water slurry before feeding the steeping liquid i.e. sulfureous acid first. After that the sulfureous acid will be quantitatively fed into the steeping tank. The steeping temperature will be controlled by means of recycling the steeping liquid through the heater in the steeping tank system and the steeping time will be controlled also. The gluten will be extracted out from the maize with sulfureous acid and the maize will absorb some water during steeping. In the result the steeping liquid containing the substantial quantity of gluten will be produced and can be processed further for production of the concentrated maize syrup or directly discharged without treatment. Some dilute spent maize slurry has to be discharged out of the processing system to keep the maize syrup clean enough for production of qualified maize starch.

Germ separation

After completion of steeping the wet maize is discharged from the steeping tank and pumped into the maize dewatering screen where the steeping liquid is separated from it. Then the wet maize goes into the wet maize bin. Then the wet maize is fed into the germ stripping mill where the wet maize is broken into the small pieces of maize, and in the result the small pieces of maize, the germs and fiber are separated from each other. The maize syrup discharged from the mill comes to the middle tank and then is pumped to the hydro-cyclone, by which the most part of germs are separated from it. 

The top-stream from the hydro-cyclone, which contains mainly germs, will pass through the gravity crank screens in series, in which they are washed with recycle water. Then the liquid is removed from the germs by the screen and the dewatering machine. After that the wet germs are fed into the dryer where they are dried by heating with steam, and the dry germs are available, which shall be packed and kept in the by-product warehouse for sale to the oil mill as feed for production of corn oil. 

Then the bottom-stream coming out from the hydro-cyclone will pass through the second germ stripping mill to separate the remainder germs contained in the maize from it. The maize syrup coming from the germ stripping mill contains some germs and will pass through the hydro-cyclone to separate the germs from it. The top-stream containing germs return to the middle tank for processing again and the bottom-stream containing starch and fiber will pass through the screen and the impacting type mill to separate the fiber from starch. 

The stream containing fiber is pumped to the fiber crank screen group, which consists of 7 sets of pressure crank screens and fiber washing tanks as well as 6 sets of recycle liquid pumps, where the fiber will be separated out and washed fully with the recycle water to remove the starch attached on it. The clean fiber will pass through the gravity crank screen and the fiber extrusion dryer（de-watering machine）to remove the moisture from it as much as possible before being fed into the dryer. Then the fiber is fed into the dryer where they are dried by heating with steam, and the dry fiber will be available as product for selling or as raw material for processing the animal feed, if necessary it can be pulverized further by the pulverizer.

The crude starch milk streams coming from the fiber crank screen group and the fiber screen will be collected in the crude starch milk pond. Before being fed into the gluten separating machines the starch milk will pass through the sand remover and the rotary filter to remove sand and other foreign substances. Then the starch milk is fed into two gluten-separating machines where the gluten is separated from the starch.

The gluten stream from the gluten-separating machines is pumped into the gluten-floating tanks where the gluten is separated from the starch further by means of their density difference and the gluten will float on the liquid. The gluten liquid is pumped into the vacuum filter for removing the water from it. The filtrate discharged from the vacuum filter is pumped into the gluten filtrate collecting tank where gluten will settle down to separate from water. The gluten liquid separated returns to the process system and water is discharged to the waste water treatment unit. 

After dewatering the concentrated gluten will be fed by the screw feeder into the dryer where it is dried by means of heating with steam and the dry gluten powder will be available. After being pulverized to the specified fineness the gluten powder can be sold as by-product for use as raw material for processing the animal feed. The under-stream discharged from the gluten-floating tanks is mainly water and recycled to the process system for reuse. 

After fully separating gluten from the starch milk, the starch milk is pumped into the hydro-cyclone group, which consists of 12 sets of the hydro-cyclones and 11 sets of recycle pumps, where the starch is washed with drinking water for fully removing gluten from starch. The clean starch milk is pumped to the overhead tank, and will be used as feed for the drying system. 

 Starch drying:

The starch drying system includes the starch-dewatering machine, the hot air-flow dryer, cyclone collector, fans, air heater as well as some conveyors and feeders. First the clean starch milk flows into the starch-dewatering machine where the liquid is removed from it, then the wet starch is fed by screw feeder into the drying system where it contacts with hot air generated by the steam-heater, in result water contained in the wet starch is evaporated out and the dry starch powder is available. After screening the starch powder with specified fineness is available and then weighed and bagged in the bag with 25Kg capacity for sell.