Potato Starch Processing Line For Potato Starch Extract Processing

System Flow Chart

Technical description

1. Raw material receiving unit

The raw material receiving unit is the first link of potato starch processing. The main purpose of this unit is to preliminarily remove impurities and store the potatoes in the raw material storage tank smoothly.

After the fresh potatoes are weighed by the platform, they are pulled to the potato storage tank, and the potato raw materials are sieved through a vibrating screen to remove part of the gravel in the potatoes. The clean potatoes fall from the vibrating screen to a belt conveyor, which transports the potatoes into the potato raw material storage tank. The sand, gravel and impurities under the sieve are loaded on the truck and transported by the farmers. In the process of unloading the potatoes, it is best to use a special shovel to keep the potatoes intact. The potato storage time should not exceed half a month, and the longer the potato storage time, the more unfavorable the production of starch.

The most important thing in this unit is to allow the potatoes to remove the sand and gravel impurities mixed in the harvest. The vibration of the vibrating screen can make the sand and gravel sticking to the potatoes fall off. Preliminary sand removal and impurity removal can reduce the burden on the machines in the subsequent stone removal and cleaning section. It should be noted that in the process of purchasing potatoes, the potatoes should not be damaged. The damaged potatoes are easily rotten, and the rotten potatoes can easily infect the surrounding potatoes. Poor potato raw materials have a great impact on starch quality.

2. Raw material conveying unit

The main purpose of this unit is to transport the potatoes in the potato yard into the screw conveyor through the water flow, and then transport them to the stone remover through the launder. In the process of conveying, the potatoes are continuously rolled and rubbed in the water flow, which can peel off the sticky soil on the potatoes, which has a good cleaning effect.

In the production of starch, the raw materials are fed into the raw material silo by the loading truck, and the raw materials are transported into the chute by the screw conveyor under the raw material silo. At the top of the chute, the flushing water pump is pumped into the chute by the pump, and the potatoes are transported by the water flow. Evenly enter the stone remover along the flow trough.

The smoothness, shape and slope of the flow trough play a crucial role in the flow of potatoes. The bottom of the flow trough we designed is semi-circular and the slope is reasonable, which can well transport the potatoes into the stone remover evenly. A separately added flushing pump can ensure that the flow trough will not block material in the case of improper operation.

3. Stone removal cleaning unit

A clean raw material plays an important role in the processing of potatoes, therefore the stone removal and cleaning unit is the most important in the pretreatment stage of the raw material. This unit is to completely remove foreign objects such as gravel and soil in the potatoes, and store the cleaned potatoes in the potato temporary storage hopper.

The potatoes are transported by water flow into the reverse spiral stone remover for cleaning and stone removal. The rotary drum of the stone remover is divided into two parts: the sand discharge drum and the screen drum; the screen drum wall is provided with screen holes according to the process requirements. In addition to the sand particles whose diameter is smaller than the screen hole when the stone machine is working, it will leak from the screen hole to the screen cylinder. Under the action of the reverse push spiral belt on the outer wall of the screen cylinder, it will advance in the opposite direction of the water flow and fall into the sand collection before the stone remover. In the tank, the sand discharge drum is discharged to the stone miscellaneous discharge port through the sand discharge plate. Stones, bricks and other heavy debris with larger diameters will stick to the inner wall of the screen cylinder after entering the screen cylinder because they do not float. Under the push of the reverse spiral belt in the screen cylinder, they will advance against the direction of the water flow and fall into the sand discharge drum. Inside, it is excluded together with the collection of sand particles with smaller diameters.

The potatoes after stone removal pass through the flow trough and the dewatering grille with the water flow, and then are sent to the drum cleaning machine to clean the potatoes. Drum washers work at low liquid level to thoroughly wash potatoes. The rotation of the drum makes the potato tubers rub against each other strongly to achieve the washing effect. At the same time, clean washing water is fed from the discharge port of the washing machine. Water and potato peels are discharged. The cleaning water can be transported by the circulating pump to the flow tank as flushing water to achieve recycling.

After the washed potatoes come out of the drum washing machine, they fall on a screw conveyor with spray. Several rows of nozzles are evenly distributed on the screw conveyor, and fresh water is sprayed on the potatoes through a certain pressure, further taking away the dirty water on the surface of the potatoes. The cleaning water can be drained into the collection tank under the conveyor belt through the mesh belt, and transported to the discharge port of the cleaning machine by the circulating pump to achieve recycling. The final clean potatoes are sent to the potato temporary storage bin through the spraying screw conveyor. The volume of the potato bin is generally designed to store one to two hours' worth. The specially designed screw conveyor can ensure that the raw material can fully fill the potato bin.

4. Filing the pumping unit

The filing unit is the most important link affecting the extraction rate of potato starch. The high-efficiency filing machine can completely release the starch granules in the potato cells and ensure that the content of bound starch in the potato residue is reduced to a minimum.

A specially designed discharge port is connected below the potato bin, and the discharge port is connected with a speed-adjustable feeding screw. The feeding screw has three outlets, two filer ports and one overflow port. There is a short circuit with a flapper valve between the filer and the feeding screw. When the system wants to feed, first open the flapper valve on the file mill, then adjust the frequency of the feeding screw as needed, and start the feeding screw to start feeding. The filed potato pulp is pumped into the desander unit with a fiber pump.

The specially designed stainless steel filing machine is very easy to operate. The compact file clamping system ensures that the file works in the best position. The loading and unloading of the file is very simple, and it can be done by ordinary people without the use of special tools at all. The stainless steel screen is a one-piece construction and can be replaced without tools, allowing the filer to achieve maximum efficiency and starch yield. The distance between the file and the fixed block is 1~2mm to ensure higher filing efficiency. The capacity of the entire line can be adjusted by means of a speed-adjustable feeding screw.

5. Cyclone sand removal unit

The rasped potato slurry is pumped by a fiber pump into a desander cyclone. The material with a certain pressure overflows from the top, and the heavy-phase sand particles are discharged from the bottom. There is a sand accumulating tank under the ceramic swirl tube. The sand accumulating tank is connected with pressure backwash water to ensure that the starch will not be lost from the bottom flow port, and the discharged sand particles are regularly discharged through two airbag valves.

We use specially manufactured ceramic swirl tube for durability, and the uniquely designed air bag valve can automatically and regularly discharge the sand.

6. Centrifugal extraction unit

Centrifugal extraction is another key unit of the entire production line that affects the yield of potato starch. A good centrifugal sieve and process can extract the free starch that is broken from the potato cells.

The extraction unit is a centrifugal sieve group consisting of three centrifugal sieves, each of which is equipped with a fiber pump and a defoaming pump. The potato pulp from the desander enters the first-stage extraction screen. Under the centrifugal force of the high-speed rotation of the screen basket, the pulp passes through the screen and the potato residues remain on the surface of the screen basket to be thrown out. There is a certain pressure of flushing water on the front of the screen basket at all times, which is sprayed from the nozzle to make the potato dregs roll continuously, so that the starch in the potato dregs can be fully separated. The back of the screen basket is also designed with flushing water, but the back flushing water on the back is regularly turned on to ensure that pectin and potato residues do not block the screen. The starch milk is pumped to the cyclone station for washing by the defoaming pump, and the potato residue is pumped to the second-stage centrifugal screen by the fiber pump. The potato dregs containing a certain amount of starch are further extracted into the second stage centrifugal sieve, the starch-containing water enters the process water of the extraction system through the defoaming pump, and the potato dregs continue to be pumped to the third stage extraction sieve through the fiber pump. Similarly, the third-stage extraction sieve still performs starch extraction, and the sieve still enters the process water of the extraction unit, while the potato residue is pumped to the potato residue dehydration unit.

The three-stage series centrifugal sieve group can ensure that all free starch is collected into the extraction system, so that the potato residue does not contain free starch, which fully guarantees the extraction rate of starch. Unique process design and excellent equipment performance ensure that we can completely extract free starch from potato residue.

7. Potato residue dehydration unit

We use a centrifugal sieve to dehydrate the potato dregs pumped from the extraction unit, and the working principle is the same as that of the extraction sieve. The potato residue is finally transported out of the workshop through a screw conveyor, and the water from the potato residue is still returned to the process water system of the extraction unit.

8. Concentration and purification unit

Concentration refining is the most important unit of the entire production line, and the quality of starch is completely guaranteed in the cyclone refining unit. The impurities in the starch slurry are completely removed by physical methods, so that it does not affect the quality of starch products.

The starch slurry from the first-stage centrifugal screen enters the 16-stage concentrated cyclone washing unit, and the process water is pumped from the other end of the cyclone station to wash the starch in a countercurrent manner. The entire cyclone station can be divided into three parts. First, the starch slurry is dejuiced and concentrated through the concentrated cyclone station. The concentrated starch milk enters the 13-stage washing unit, and the cell liquid from the overflow enters the two-stage recovery cyclone. The flow station recovers the starch contained in it. Most of the waste liquid overflowing from the cyclone station containing a large amount of fiber impurities is directly discharged, and a small part still enters the process water system of the extraction unit. The starch milk from the cyclone station is pumped into a stainless steel starch milk storage tank with an agitator.

Clean process water is added from the last stage of the cyclone station, mixed with starch milk for washing, and then the overflow is mixed with the previous stage of starch milk, washed and separated, so that the first-stage counter current washing makes fibers and cell fluids discharge with water. Swirl Station. The thirteen-level washing can ensure the washing effect of the cyclone station, better remove impurities such as fiber and protein contained in the starch milk, and ensure that there are no impurities in the starch milk coming out of the cyclone station. In this way, it can be ensured that all indicators of the produced starch meet the standards.

9. Vacuum dehydration unit

The water content of the starch milk coming out of the cyclone station is too large to be directly dried, so it is necessary to dehydrate the starch milk first, so that the starch water content is about 40%.

The starch milk is pumped from the starch milk temporary storage tank to the vacuum dehydrator tank with a starch pump, and a water pipe is connected to the starch milk pipeline, and the starch milk is diluted to a certain concentration with process water. The vacuum pump forms a negative pressure in the vacuum drum. When the starch emulsion contacts the vacuum drum, the starch slurry is sucked on the drum surface, the filtrate is sucked into the filtrate separation tank and pumped away by the filtrate pump, and the filter cake is scraped off by a scraper , and transport it into the feeding hopper of the air flow dryer with a food-grade conveyor belt.

Our vacuum dehydrator has excellent performance, simple and stable operation, and the moisture content of starch after dehydration is very low, which greatly reduces the energy consumption of subsequent air drying.

10. Air drying unit

The air dryer further dries the dehydrated starch to the moisture content required for commercial starch. The air is heated to the required temperature by the heat exchanger through the filter screen, and the hot air is sucked into the dryer by the induced draft fan. The dehydrated starch is transported to the feeding screw with a hopper, and is transported to the feed port of the airflow dryer through the screw, and the starch enters the cyclone separator along the air duct along with the hot air in the airflow dryer, and the dried starch is in the cyclone separator. The cyclone separator is separated from the air, and the wet air is discharged through the induced draft fan after leaving the cyclone separator. The starch enters the finished spiral through the air shutoff below the cyclone. The specially designed large-bend airflow dryer has been proved by practice that its energy consumption is reduced by about half compared with the average level.

11. Screening storage unit

The starch is conveyed into the starch homogenizing silo through the finished product screw, and then the starch is conveyed into the bucket elevator through the lever feeder under the homogenizing silo, and the bucket elevator conveys the starch to the two-way conveying screw. If the moisture content of the starch does not meet the requirements, the starch is returned to the uniform bin through the bidirectional conveying screw; if the moisture reaches the standard, the starch enters the double-silo vibrating flat screen through the bidirectional conveying screw, and the vibrating screen sieves and grades the dried starch and removes the The gelatinized and coarse particles in the refined starch make the fineness of the finished starch meet the standard. The sieved starch directly enters the stainless steel starch bin for temporary storage. The selected double-silo flat screen specially used for starch has the mesh number of the screen gradually increasing from top to bottom, which ensures the smoothness of starch screening and the fineness of starch.

Adopting a uniform silo can ensure the balance of the product. If the moisture of the dried starch is too dry or too wet, the circulation of the uniform silo will make the moisture meet the standard. Especially when the air dryer is unstable at startup, the uniform silo can ensure that the starch moisture content is evenly up to the standard.

12. Weighing packing unit

The starch in the starch silo is packed into 25kg bags by an automatic packaging machine.