1. Pulp and residue separation:
Slurry separation equipment is all stainless steel pressure curved screen, this screen is the most advanced screening equipment at home and abroad, no vibration, high efficiency, easy cleaning, long service life.Five groups of pressure curved sieve are used together, the first pressure curved sieve is used to separate the material after the first crushing, the material on the screen is big slag and then go to the second crushing, the pulp is coarse pulp.The second pressure curved screen is used to separate the materials after the second crushing, and the materials on the screen after the second screening go directly into the third pressure curved screen, and then push back.
Two to five curved screen are used to clean starch, each time with the return of water after the road cleaning, two coarse pulp and a coarse pulp combined, after the sand removal device to remove fine sand into six curved screen fine.Three curved sifter of water as the return water, return to the return tank to save, into the crusher and crusher use.After five times of curved sieve, the slag is thoroughly cleaned, and the residue is treated as feed, or dried after dewatering by fiber press for easy storage.
The pressure curved screen is based on certain pressure to complete the screening, so that pulp residue separation, to achieve the purpose of extracting starch, starch yield plays a certain role.Therefore, it is necessary to adjust the nozzle Angle above the curved screen.Adjust the feed pressure and control the amount of water added. The pressure of curved sieve is required to be 0.2-0.4mpa.Operators should always pay attention to the normal operation of curved screen pump, adjust the valve above the curved screen, ensure the pressure load, prevent the blockage of pump mouth materials, and cooperate well with the upper crushing section, during the shift to clean the screen surface with water, to ensure the smooth operation of the full set of pressure curved screen.
2. Sand removal and over-fining:
Sixth pressure curved sieve to carefully screen, screen plasma for the finished product, to carefully screen in front of the coarse pulp contains sand, must be removed by the desander, desander is to rely on pressure rotating make heavy material under the action of centrifugal force, to the outer wall, sinking to the bottom, and the lighter material (starch), after pressure rotating on the desander center, from the upper discharge, achieve the goal of sand.Lower feed sand time for 30 minutes once, via a desanding can remove 95% of the sand, sand through second bed cleaning basically the shaved, desander work pressure of 0.2 0.3 Mpa, but must explain the point is: desander is not desilter, fine mud in starches when proportion and starch grains, mud can add in the starch is not easy to remove, so, cassava should as far as possible will mud cleaned before production.
Operators should pay attention to the pressure of the desander, and it is required that 0.2-0.3mpa should not be allowed to release sand at any time for 30 minutes. The released sand also contains some starch, and a small amount of starch can be removed by adding water precipitation in the container.
3. Rotary filtering:
This process is designed to ensure the normal operation of disc separator, which is a precision machine, and the nozzle diameter is 1.2-2.0mm, which is easy to be blocked by small particles. The rotating filter is installed at the entrance to the disc separator to check.Because some unexpected impurities may enter the pulp during production and damage the disc separator if not controlled, the rotating filter can also play a very large role.
4. Secondary separation of disc player
Disc separator is an efficient and advanced equipment for separating protein. It can separate about 80% protein at one time, and the starch milk after the second separation can reach the protein content of <0.5%.
Disc separator is an effective and advanced protein extraction equipment, introduce our country since the 80 s, has been widely used, separator mainly drum, nozzle and various return line and the import and export of drum with a group of dozens of pieces of stainless steel discs, with 0.5 1 mm gap between disc and drum rim several tungsten carbide nozzle, coarse starch milk by upper inlet into the drum, high-speed rotating drum drive material, produce a lot of centrifugal force, make the disc space in different proportion of starch and protein separation, than big starch particles are thrown to the drum wall, the nozzle flow output from the bottom,The light weight of the protein moves along the disc toward the center with the flow of water and is discharged through the overflow port to achieve separation.As the potato protein content is less than grain, it can isolate about 80% of the protein, two separate can make protein content <0.5%.After the separation of starch milk in the circulating tank add sulfite water, adjust the PH value, can improve the whiteness of starch.
Complete set of mechanical equipment for cassava starch processing production line
5. Cyclone washing refinement:
After white starch milk, there is still a small amount of insoluble protein, 0.2-0.3% soluble protein and other minerals, which will seriously affect the quality of starch, making its main products such as syrup, glucose, medicine, textile and so on fail to meet the quality standards.
The cyclone group is made up of nine serial units, which mainly have three workrooms and dozens to hundreds of cyclone tubes and slurry pumps.Starch milk from upper vortex tube cutting at high speed to import into, due to the high speed rotating centrifugal force makes the solid particles with spiral flow down to the bottom, mixes after discharge and the overflow of the level of water, into the next level of cyclone, push the class as a condition, the level of water (according to the requirements of normal use 40 ℃ soft water), the work order for starch themselves walking back, wash water from behind themselves walking forward, form a countercurrent washing, make our products meet national standards.
The protein content is the main index for testing the quality of starch, and the protein content exceeds the standard directly affects the range of use of starch, such as glucose injection. If the protein content is too high, the starch will appear mildew, white spots and other phenomena, so the production of starch to reduce the protein content is a key process.
Most of the starch production by the native method adopts the flume method of pool precipitation to remove the protein, which occupies a large area and cannot accurately control the protein content, so it can only rely on experience, therefore, it restricts the yield and the quality of starch.The above problems have been completely solved by disc separation and swirl washing technology.After secondary protein separation, a certain amount of whitening substances can be added to make it fully react and improve the whiteness of starch.Enter the cyclone unit, add a certain amount of water, thoroughly separated protein and starch.The primary and secondary disc separation and the cyclone set are connected by a transfer tank to form a continuous operation process.
Disc separator is a kind of high precision equipment, which requires the operation of trained personnel with a certain degree of education.
6. Starch dehydration:
At present, starch dehydration equipment is divided into three categories: one is the three-foot feeding and discharging centrifuge, its labor degree is large.The second is the automatic scraper centrifuge, although the automatic operation, but power consumption (30KW), expensive accessories (about 10,000 yuan per year).Third, our company is equipped with vacuum drum dehydrator, this machine consumes less power (8KW), belongs to all stainless steel equipment, low rotation speed (9-12 RPM or so), the machine is not easy to damage, energy saving effect than similar products about 70%, easy to operate.
Before using the vacuum drum filter and dewaterer, the filter is put into the starch slurry. When the starch absorption thickness on the surface of the press cloth is 5-6mm, the scraper is adjusted to scrape off the starch.At the same time, keep the starch 3-4mm thick on the press cloth, adjust the feed rate and observe the dehydration effect.If the material humidity is too high, the machine speed can be slowed down, the dehydration effect will be better.The moisture content of wet starch after general dehydration is in 39% or so is good, if the moisture content is high, the drying difficulty will increase.
It should be noted that the vacuum dewatering filter should be operated by professionals, and generally not disassembled randomly. When the equipment is running for a period of time, it should be cleaned in time to prevent acid substances from corroding the press cloth.The dehydrated starch can go directly into the dryer for drying.
The air collision dryer USES coal as fuel, hot air flows into the heat exchanger, and the clean air entering the heat exchanger at the other end becomes hot and dry air, which is fed into the drying tower and mixed with wet starch with water content less than 40%. The water is vaporized in 2-3 seconds and discharged through the separator.
Drying tower adopts positive and negative pressure two-stage drying, wet air is discharged from the first stage, while the second stage is discharged from the air with higher temperature into the feed pipe for reuse, compared with single-stage drying, energy saving is 20-40%.
The feeding conveyor adopts stepless variable speed, which can be arbitrarily adjusted according to the different climate and materials.
There is an automatic temperature control device in the heating system, which can set the temperature of dry and hot air arbitrarily according to the need, and keep a certain temperature all the time, so that the quality of starch can reach a stable and consistent effect.