Section 1 Broken and Softened

1. Crushing of oil

Crushing is the process of reducing the particle size of oil.

(1) Purpose and requirements of crushing

1. Purpose

Vegetable oil plants have two types of crushing in the process of oil production. One is that large-grained oil plants must be crushed, such as peanuts, soybeans, and tung seeds. First of all, because large-grained oil is not suitable for flaking, the grains are not easy to enter the gap between the rolls of the flaking machine, so it must be made smaller to meet the flaking conditions. Secondly, it is difficult to adjust the moisture and temperature of the large-grained oil, so that the moisture and temperature of the oil are uneven inside and outside, and the required plasticity cannot be achieved, and the green embryos that meet the requirements cannot be prepared, thus affecting the production of oil. The other is that the pre-pressed cake or the one-pressed cake must also be crushed, so that the larger cake pieces become smaller ones, which is conducive to leaching oil production or secondary pressing oil production after moisture temperature adjustment and embryo rolling. .

2. Process requirements

The requirements for the crushing process generally vary with different oils and process requirements. In general, the requirements are:

(1) After crushing, the particle size is uniform and meets the specifications. Soybeans are generally broken into 2-4 petals, peanut kernels are generally broken into 4-6 petals, tung seeds are controlled at 8-12 petals, and oil cakes are preferably broken into diagonals of about 6-10 mm.

(2) No oil, no lumps, less powder. The weight requirements of the crushed material passing through the 20-mesh/25.4mm sieve: peanut kernel <8%, soybean <10% (using a disc sheller) or <5% (using a roller crusher).

(3) Moisture requirements. In order to meet the above process requirements, the moisture content of the oil before crushing should be appropriate. If the moisture is too high, it is not easy to break, and sometimes it will be flattened, agglomerated, and oily, which will affect the leaching effect; if the moisture is too low, it will cause large powder degree and uneven particle size. Generally, it is required to control soybean moisture at 10-15%, peanut kernel 7-12%, and tung seed 11-15%. The moisture content of pre-pressed cake is generally about 7%.

(2) Broken equipment

1. type

The crushing equipment commonly used in vegetable oil plants can be divided into roller crushers, toothed roller crushers and hammer crushers according to different structures. These crushing equipment usually use extrusion, shearing, impact or a combination of several methods to crush oil.

The grooved roller crusher can be used for crushing soybeans and peanut kernels, and the toothed roller crusher can be used for the primary crushing of whole coconut flakes and large pre-pressed cakes. In addition, the disc sheller can also be used as a crushing device, but it needs to be replaced with a square grinding disc, and the speed can be reduced to 200-300 rpm.

2. crushing equipment

Common crushing equipment is mainly roller crusher and toothed roller crusher.

(1) Roller crusher. Roll crushers are divided into two types: single-roll crushers and double-roll crushers. Their structure is basically the same, but the former is simpler than the latter, and the power consumption is correspondingly smaller. The specific selection should be determined according to the actual production situation. The double-roller crusher is now introduced as follows.

After the oil enters the feed hopper, it first falls between the upper pair of crushing rollers for crushing, and then falls between the lower pair of crushing rollers for the second crushing. One roller surface of the upper crushing roller has warp teeth, and the other roller surface has weft teeth, so this pair of rollers is also called warp and weft rollers, while the two roller surfaces of the lower pair of crushing rollers are helical teeth. The distance between the two rolls is adjusted manually by a rolling distance adjusting device. The crushed oil is discharged out of the machine from the discharge hopper.

The transmission of the double-roller crusher is driven by two fetchers respectively to drive two pairs of V-belt pulleys to make the upper and lower crushing rollers rotate.

(2) Toothed roller crusher. The toothed roller crusher is composed of feeding hopper, toothed roller, roller distance adjusting device, machine base and transmission mechanism.

When the toothed roller crusher is working, the oil material falls evenly from the feeding hopper between the two oppositely rotating toothed rollers for crushing. The toothed roller is formed by stacking zigzag discs and fillers. The distance between the two rollers is adjusted by the adjusting device to control the degree of breakage of the oil cake. The crushed oil is discharged from the lower part of the machine base.

(3) Operation and maintenance of crushing equipment

Operation points:

1. The crusher should be prepared and inspected in strict accordance with the operating procedures before driving. After driving, it should be run empty for a short time to check whether the transmission parts are flexible. After the no-load is normal, the material can be put into production.

2. In the production process, the flow rate is controlled by the material gate, and the crushing particle size can be achieved by adjusting the roller gap through the spring adjustment mechanism. When the gap needs to be adjusted, it must be stopped for adjustment to avoid accidents.

3. When the machine is working, it is necessary to ensure that the material in the material box is half full, so that the feeding is uniform, so as to achieve uniform wear of the roller surface and prolong the service life of the toothed roller.

4. If iron blocks or other hard debris are found to be stuck on the crushing roller during operation, it is necessary to stop the crusher in an emergency, loosen the roller, manually turn the car or use special tools to take out the debris. Before restarting the machine, it must be operated with no load, and only after everything is normal, the feeding can be continued.

Maintenance points:

1. The oil should be screened and magnetically separated before entering the machine. Do not mix hard materials such as iron and stone into the machine to avoid damage to the roller surface.

2. When the crusher is crushing the oil, the roller surface will gradually wear out. When the wear reaches a certain level, it should be repaired in time. Such as redrawing or replacing the rollers.

3. When adjusting the distance between the crushers, pay attention to keeping the two rollers parallel to each other to prevent skew.

4. Always check whether the lubrication of each lubrication point is good during operation, and check the bearing temperature. The bearing temperature rise should not exceed 40 °C, and the maximum temperature should not exceed 75 °C. If there is abnormal vibration and noise at the bearing, it should be stopped for inspection and troubleshooting.

5. Under normal circumstances, do not use the new belt and the old belt together, because the lengths of the two are different when they are stretched. When working, the V-belt should be tightened regularly. Generally, it is required to check the V-belt every 300 working hours. In order to improve the service life of the V-belt, it should be avoided to work at a temperature higher than 70 ℃ for a long time.

6. The vibration of the machine should be checked frequently. If the vibration is found to increase, it should be checked whether the concentric operation of the rollers exceeds the regulations of the machine.

2. Oil softening

Softening is the process of properly adjusting the moisture and temperature of the oil to make its tissue soft and suitable for flaking.

(1) The effect of softening and process conditions

1. softening effect

The function of softening is to adjust the moisture and temperature of the oil to change its hardness and brittleness, so that it has suitable plasticity to facilitate rolling.

Softening is essential for lower oil content, hard and brittle oils such as soybeans, cottonseeds with low moisture content, and rapeseed. If the embryo is rolled without softening, it will inevitably produce a lot of powder or the rolled embryo will be too thick, which is not good for pressing or leaching to make oil, and will seriously affect the oil yield. Therefore, softening must be carried out for this type of oil.

For oil crops with high oil content, such as peanut kernels, castor seeds, tea seed kernels, coconuts, etc., it is generally not softened and directly rolled, otherwise it is easy to cause undesirable phenomena such as oil production during embryo rolling.

2. softened process conditions

The softening process conditions should generally be mastered according to the moisture content and oil content of the oil, and the temperature and moisture should be adjusted appropriately.

 (2) Softening equipment

The most widely used softening equipment is the layer softening pot.

1. Layer softening pot

The layer softening pot is a layer softening equipment with a cylindrical pot body and a steam interlayer and a stirring device. It consists of a stirring blade, a discharge port, a steam pipeline and a transmission device. It is basically the same as the steam frying pan, except that the number of layers is less. Generally, when the softening pot is working with 2 to 4 layers, the oil enters the first layer of the pot body, and is heated by the steam interlayer. With the stirring blade, it falls from the material door into the second layer. The layer pot continues to heat, so that the heating layer by layer, until the bottom layer is discharged from the discharge port. There is a wetting device in the first layer of the pot, which can adjust the moisture content of the oil.

2. Other softening equipment

Other softening equipment includes steam auger and softening box.

The steam auger is a screw conveyor with a steam heating jacket. It is heated in the process of conveying, and its helical blade adopts paddle type and crescent type, which can make the material continuously flip during the slow advancing process and can be heated evenly. In order to prevent the steam in the screw conveyor from escaping and maintain the temperature in the machine, the machine should be made into a closed type. In addition, a steam nozzle is installed in the machine for steam wetting.

Since the steam auger is softened during the conveying process, when the distance is long, the softening conditions are easier to control, the oil can be softened sufficiently and evenly, and the process can be simplified and the equipment can be reduced. But the heat transfer effect is poorer.

The softening box is often installed directly above the flaking mill. It is a container with a conical bottom, with a steam interlayer outside and a steam pipe inside to soften soybeans or other oils. It can also be directly sprayed with steam or heated water to adjust the moisture of the oil. The device does not require power and is more economical. The disadvantage is that the softening is uneven, and the dead corners are easy to accumulate and burn, causing oil loss and reducing thermal efficiency.

(3) Operation of softening pot

1. Check the steamer of each layer before driving, remove the sundries, and then adjust the material door to the required position. Generally, the first and second layers are not less than 80% of the material, and the rest of each layer is about 40%, so that the The water vapor is discharged during the softening process.

2. Check whether the clamping bolts of the stirring scraper are loose. When the scraper is being transported, avoid contact with the bottom and sides of the pot, and generally leave a distance of about 5mm between them.

3. First turn on the motor for empty car operation, check the normal operation and then feed the material.

4. Before feeding, first open the inlet and outlet valves of steam or heat-conducting oil, and start feeding after preheating the pot body. When there is a certain level of material in the pot, spray direct steam or add water to adjust the moisture content of the oil. Note that the size of the discharge flow should be consistent with the feeding amount.

5. During the operation, attention should be paid to adjusting the direct steam pressure and the temperature of the heating medium to control the temperature and moisture of the oil to meet the process requirements. See Table 3-5 for the specific process requirements.

In order to grasp the moisture content of the oil, one is to regularly sample and test the moisture content, and the other is to see the effect of the next rolling process. In short, if the water content of the oil is low, it is necessary to add enough water when softening; if the water content of the oil is high, less water should be added, and if it is too high, no water should be added.

The softening temperature of the oil is generally controlled according to the moisture level of the oil. If the water content is high, the softening temperature should be lower (not at this time).

Add or less water), the softening temperature can be higher for the low water content, so that the oil has suitable plasticity.

6. Ensure sufficient softening time. During the softening operation, it often takes a certain amount of time to make the oil penetrate the water vapor and achieve a uniform temperature. The specific softening time varies depending on the oil and softening equipment. Commonly used layer softening pot, the specific time is generally 10-15 minutes.

7. During the operation, the bearing and the gear box should be checked frequently, and lubricating oil should be added regularly to ensure the normal operation of each part.

8. When stopping, first stop feeding, drain all layers of oil, close the heating medium and the direct steam inlet valve at the same time, and finally turn off the motor to stop.

In case of emergency shutdown for some reason, the motor should be turned off immediately, the steamer feeding should be stopped, and the heating medium and the steam inlet valve should be closed. Then remove all the oil in the pot from the inspection door. Check if it is in good condition, and then restart the drive to feed the material according to the driving sequence.

Section 2 Rolling

Flaking is the process of mechanically pressing oil into flakes. The embryos after rolling are called raw embryos; the raw embryos are called cooked embryos after being steamed and fried.

First, the purpose and requirements of rolling

(1) The purpose of rolling

1. destroy cell structure

The oil cell has a relatively tough cell wall on its surface, and oil and other substances are contained in it. Therefore, in order to extract the lipids in the cells, it is necessary to destroy the cell wall on the surface. The rolling of oil seeds is to press the oil seeds from granular into flakes by means of the rolling of the rollers and the mutual extrusion between the oil cells, so that the cell walls are damaged. At the same time, the oil body protoplasm inside the cell and the tiny structure of the cytoplasmic gel in it will inevitably be damaged. The more oil cells are destroyed during embryo rolling, the more oil is adsorbed on the surface of the raw embryo, and the easier the oil is to be extracted. In general, the thinner the embryo is rolled, the more cells are destroyed.

2. shorten the oil circuit

After the granular oil is rolled into flakes, the distance for the oil to be extracted from the oil is greatly shortened, thereby providing favorable conditions for the oil production process by pressing or leaching.

3. Good for steaming

After the oil is rolled into thin slices, the surface area increases and the thickness decreases, so that the embryo is easy to absorb water and heat during steaming and frying, and it is also convenient for the evaporation of water, which is more conducive to the denaturation of the protein in the embryo and the change of cell properties. Change.

(2) Requirements for rolling embryos

1. Feeding requirements

The gap between the rolls is very small, and the oil entering the flaking mill should be properly treated in advance. For large-grained oil such as peanut kernels and soybeans, it should be crushed first. For soybeans with low oil content and low moisture content and hard tissue. Oilseeds such as rapeseed and cottonseed need to be softened.

2. embryo thickness

The embryo sheet after rolling is required to be thin and uniform, less powdery, and oil-free.

2. Rolling equipment

(1) The principle of rolling

The flaking mill is a device that uses the rolling force generated by the rollers to press the oil from granules into flakes.

When the rollers of the tandem flaking mill are working normally, the material to be pressed is subjected to three forces: the weight of the material G, the resultant force R2 of the reaction force P of the positive pressure of the roller facing the pellets, and the resultant force R1 of the friction force F.

To make the flaking machine work normally, the conditions must be met: R1+G>R2. However, because the pellets are very small, G can be ignored, so the above condition becomes R1>R2, that is, the frictional force on the roll surface of the pellets in the working range must be able to overcome the upward thrust of the rolls on it before being pulled into the rolls. between. The above conditions are shown in Figure 3-4, and further calculation can be obtained:

φ＞α

In the formula: φ——the friction angle of the material particles to the roller surface;

α——The meshing angle of the material particle to the roll, that is, the angle formed by the center line of the two rolls and the contact point M of the oil and the roll to the center line of the roll.

That is to say, the condition that the particles can be pulled into by the rollers and pass through the working gap between the two rollers is that the friction angle must be greater than the engagement angle.

Therefore, the larger the friction coefficient of the material particles on the surface of the roll, that is, the larger the friction angle, the greater the force to pull the material into the gap between the two rolls, and the better the rolling condition of the material. Similarly, the larger the diameter of the roll, the smaller the bite angle, and the easier it is for the material to enter the gap.

Of course, the gap between the rolls is actually very limited. In order to obtain the green embryo with the required thickness, the gap is usually very small. In actual production, methods such as oil crushing, softening and humidifying are often used to increase friction and reduce the angle of engagement. When selecting a flaking mill in process design, the size of the roll diameter and the surface groove should be considered according to the material conditions.

(2) Rolling equipment

The type of flaking machine is divided into three forms: flat row, inline row and oblique row according to the arrangement of its rollers. Vegetable oil plants mainly use the first two, the latter is relatively rare. Flat row flaking machines include single-roll flaking machines and double-roll flaking machines. In-line flaking mills include three-roll flaking machines and five-roll flaking machines. Various types of flaking mills are divided into many specifications according to their different roll diameters and roll lengths. Their performance and production capacity are different, and they should be selected according to different process requirements. The following mainly introduces two types of flaking mills in the form of parallel rolls and in-line rolls.

1. Flat-row flaking machine diagram The parallel-row flaking machine has two types: single-roller flaking machine and double-roller flaking machine. The working principle is basically the same. Relative rotation, forming a strip or two rolls working gap for rolling. This flaking machine is suitable for flaking of large grain oil, such as peanuts and soybeans.

(1) Structure. The structure of single-pair roll flaking machine and double-roll flaking machine is basically the same, which is composed of feeding mechanism, rolls, rolling distance adjustment device, baffle phase scraper, transmission device, frame and machine base. The single-roller flaking machine has two types: spring tight roller (YYPT-B type) and hydraulic tight roller (YYPY-A type).

①Feeding mechanism. The function of the feeding mechanism is to ensure uniform feeding along the entire length of the roll. If the feeding is uneven, the wear degree of the rollers will be inconsistent, and there will be beating during operation, and the thickness of the rolled blanks will not meet the requirements of uniformity. When it rotates continuously, the oil material evenly falls into the rolling seam through the blanking gap. The size of the cutting amount can be controlled by the adjusting door.

②roller. The roll is the main working part of the flaking mill.

The rolls are connected together by the roll body and the shaft through hot pressing and "cold shrinking", and the roll body is hollow to reduce weight, save materials and power consumption. The wall thickness of the roller body is 100-150 mm. The material of the roll is mainly cast iron and cast steel, and contains a small amount of trace elements (such as P, Mn, Si, Ni, Gr, etc.), so that it has good wear resistance and sufficient hardness (HRC50-60°). The outer layer of the roller surface is a white layer, and the depth of the hard layer is 20-50 mm.

The rolls of the parallel flaking mill are arranged in parallel, and the roll diameter is larger than that of the in-line type. The rolls are generally divided into two types: light splitting rolls and groove rolls (drawing rolls). The grooved roll is mainly used for the first roll of the double-roller flaking machine to increase the friction coefficient of the roll body to the oil, which is convenient for the roll to eat. The surface of the grooved roller is evenly opened with a sloping groove with a width of about 2 mm, a "V"-shaped cross-section and an angle of 45°.

③ Rolling distance adjustment device. The rolling distance adjustment device of the parallel flaking mill generally adopts a spring pressing device and a hydraulic tightening roller device. The main function of the rolling distance adjusting device is to maintain the pressing force between the two rolls to control the thickness of the rolled blank; Damage to the roll surface.

The spring pressing device maintains the pressing force of the two rollers by the elastic force of the spring. The rollers are placed in the wall panels on both sides and can move back and forth with the guide rails. When the nut on the wall plate is rotated, the roller shaft can be moved back and forth, thereby changing the working gap between the two rollers. After proper adjustment, they are locked with the locking nut.

Hydraulic tightening roller device uses the principle of hydraulic pressure to generate pressure. The hydraulic tightening roller system is composed of oil pump, oil cylinder, piston, connecting rod and rolling distance adjusting screw. The pressure generated by the hydraulic system can make the maximum pressure between the rolls reach]@ton, and the gap between the rolls can also be adjusted. When working, when the required oil cylinder pressure is reached, the oil pump can automatically stop feeding oil, and when the oil cylinder pressure drops to a certain limit, it can automatically start to supply oil to the oil cylinder to ensure stable pressure. This process is completed by an electrical control system, thus ensuring the stable operation of the automatically controlled hydraulic tension rollers.

Due to the strong pressure between the rolls, the hydraulic compact roll flaking machine can produce thin and strong billets with small powder degree and good quality of billets, and the production capacity of the equipment is also improved accordingly. Hydraulic tight-roll flaking mills are widely used in large oil plants.

④ scraper. The function of the scraper is to remove the blank on the surface of the clean roller. Due to the high moisture content of the oil or the extrusion of grease, some of the blanks will adhere to the roller surface and rotate with the rollers. The scraper can be used to scrape off the blanks on the surface of the roller in time to keep the roller surface smooth. The scraper usually relies on the action of a spring or a weight and a lever to keep it in constant contact with the roller surface. In addition, the scraper can also be controlled by the hydraulic system. When it is necessary to scrape off the material adhered to the roller, the scraper can automatically move closer to the roller surface to scrape the material under the control of the hydraulic cylinder and the piston. The surface is detached, so as to avoid long-term close contact with the roller surface and accelerated wear.

⑤ Transmission device. The transmission of the single-roller flaking machine usually uses two motors to directly drive the V-belt pulley on the roller through the V-belt. Most of the feeding rollers are driven by a single machine, and some are driven by the belt pulley on the roller through the V-belt. The transmission of the double-roller flaking machine generally uses several pairs of sprockets and chains for transmission.

2. Inline flaking mill

In-line flaking mills usually have three rolls and five rolls. The structure and working principle of these two types of flaking mills are basically the same. The rolls are placed vertically in sequence, and the rolled materials pass through the two or four working gaps of the rolls in sequence from top to bottom to form the flakes. The characteristics of the in-line flaking mill are that the utilization rate of the rolls is high, and the number of flaking is many, but the large-grained materials are not easy to enter the rolls, so it is suitable for flaking of small-grained oil, such as rapeseed and cotton kernels.

Now introduce the commonly used three-roll flaking mill.

(1) Structure. The three-roll flaking machine is composed of feeder, roll, rolling distance adjustment device, baffle, scraper, transmission mechanism, machine base and frame and other components.

① Roller. The structure of the rolls is the same as that of the parallel-type rolls, but the rolls of the three-roller flaking machine are arranged vertically in a staggered arrangement to facilitate feeding. The center line of the first and third rolls of the three-roll flaking machine is on the same vertical plane, and the axis center line of the middle roll (ie, the second roll) is on another vertical plane, and the two vertical planes are about 25 mm apart. The five-roll flaking machine is similar to this, and the distance between the center lines of the first, third, and fifth rolls and the second and fourth rolls is still about 25 mm.

② Rolling distance adjustment device. The rolling distance adjustment device of the three-roll flaking machine is located on the bearing boxes at both ends of the first roll. The device is adjusted by a handwheel with a screw, so that the pressure is pressed by the spring to compress the bearing box, and the pressure is successively transmitted to the lower rat-rolling machine. The whole flaking mill is in a compressed state.

The main functions of the rolling gap adjustment device: prevent the roll from jumping upward when the material passes through the gap between the rolls during the working process; control the thickness of the blank sheet; when the hard object enters the gap between the rolls, the spring sheet compresses to protect the roll from being damaged.

③Baffle phase scraper. The baffle device of the three-roll flaking machine is located on one side of the feeding gap, which plays the role of material guiding. The baffles of the three-roll flaking machine can be two or three, depending on the location of the embryo.

The scraper is to scrape off the material sticking on the roller surface. Installed below the roll, relying on the action of the spring or the weight and the lever, the scraper is kept in constant contact with the roll surface to maintain the smooth state of the work roll surface.

④ Transmission device, transmission device of three-roll flaking mill.

⑤Rack and base. The frame (also called wall panel) of the three-roll flaking machine is two detachable castings, which are combined with the frame by bolts. The machine base is then fixed on the work surface by the anchor screws.

(3) Operation points of the flaking machine

1. The oil to be rolled must meet the requirements of human rolling.

The oil must be rigorously cleaned to remove hard, bulky impurities such as stones, iron, etc. For this reason, the magnetic separation equipment must be installed before the flaking process.

Control the moisture and particle size of the oil to be rolled. The moisture should not be too high, otherwise it is easy to stick to the roller; the large particle size should be broken, otherwise it will not be easy to roll.

2. When starting up, first start the roller motor and hydraulic pump station, then start the feeding motor after tightening the roller, and then feed the material after the operation is normal. When rolling embryos, there should always be a certain amount of material in the storage hopper. The feeding should be uniform, so that the entire surface of the roll can be fed evenly. It is necessary to avoid the wear of the roll surface due to the uneven feeding, which will affect the uniformity of the thickness of the blank.

3. The rolls must be round, and there must be no radial runout or axial movement during operation.

4. The scraper should be straight, and the degree of fit between the scraper and the surface of the roller should be checked frequently during operation to prevent sticking to the roller.

5. Regularly check the quality of the blanks, and require uniform thickness and meet the requirements of the blank rolling process. During inspection, the left, middle and right sections of the roll should be sampled and compared, and if uneven thickness is found, the machine should be shut down immediately to adjust the rolling distance.

6. When adjusting the rolling distance of the flaking machine using ordinary spring tight rollers, it is necessary to pay attention to keeping the two pressing springs consistent, and at the same time, they should not be pressed too tightly, so as to avoid the bearing heating and causing serious consequences of burning the bearing; Do not idle for a long time, so as not to damage the parts.

7. The flaking machine adopts hydraulic tight rollers, and the advance and retreat of the rollers and the pressure adjustment between the rollers are controlled by the hydraulic pump station. Just adjust the position of the left and right oil cylinder pistons according to the thickness of the blank in the length direction of the roller.

Turn the lock nuts on the piston rods on both sides to the left as far as possible, so that the thread on one side of the oil cylinder is exposed by 20-30mm, turn on the transfer switch of the pump station, and start the tight roller button. When the pressure of the pump station reaches 4.5MPa, the two rollers Close to the oil pump to automatically stop, then tighten and lock the nut. According to the thickness of the blank, the pressure of the tight roller can be adjusted again.

8. When the roll does not eat, it should stop feeding immediately, and loosen the roll or stop for cleaning. The cleaned oil should be returned to the machine for re-rolling.

9. Both ends of the roll should not be rubbed with the frame, but there should not be too large gap to avoid material leakage.

10. It is strictly forbidden to touch the rolls when the flaking mill is running, or to board the flaking mill for repairs. If any debris falls into the roll, it should be stopped and taken out, and should not be taken out by hand or other tools.

11. When stopping, the feeding should be stopped first, and then the machine should be stopped after the material is finished. In the event of a sudden stop, the regulating door in the feeding hopper should be closed immediately, and the rollers should be released to release the material.

(4) Maintenance points

1. The running part of the flaking machine must be equipped with a protective cover, especially during operation, the protective cover must not be removed to ensure equipment and personal safety.

2. Before starting the machine, carefully check whether the parts are normal and whether the bearings are lubricated. When starting, it should be carried out under no load to avoid overloading the motor.

3. Always check the lubrication of the bearing. If the sleeve is found to be missing, calcium-based grease should be added in time, and the dirty oil discharge hole at the lower end of the bearing end cover should be observed at any time. If there is oil leakage, it should be added in time.

4. Always check the bearing temperature rise. The bearing temperature rise should not exceed 40 within 1 to 3 hours at room temperature. C, the maximum bearing temperature shall not exceed 75. C. If it is found that the bearing temperature rises too high or the bearing has abnormal noise, it should be stopped and checked in time. If the fault is found, it should be eliminated in time and then restarted. If the bearing is damaged, it should be replaced in time.

5. Always check the oil level of the oil level of the hydraulic pump station. If the oil level is close to the lower limit, refuel in time. Oil temp is above 70. When C, the machine should be stopped for inspection or new oil should be added, and the hydraulic oil should be completely replaced every three months. The oil used in the hydraulic pump station is No. 20 hydraulic oil or No. 20 mechanical oil. Do not use mixed oil. When refueling, it should be filtered to ensure the cleanliness of the oil and prolong the service life of the hydraulic components.

6. Always check the wear of the rolls. If the rolled blanks are found to be thick in the middle and thin at both ends, use a roll grinder to grind the rolls in time to avoid damage such as falling edges of the rolls due to concentrated pressure. Both ends of the roll should be ground once a week to form a taper of 150mm long and 0.1mm, and the roll should be fully ground once a month. If there are special circumstances, it can be repaired at any time.

7. Regularly check the wear degree and tension of the V-belt. If there is looseness, it should be adjusted in time. If there is serious wear, the new belt should be replaced in time, but the new belt and the old belt should not be mixed to avoid accelerated wear of the new belt.

8. Always check whether the bolts and nuts of each component are loose, and tighten them in time after they are found.

9. When the flaking machine is in use, there should be a special person to take care of it, and the pressure should be recorded regularly. If there is no adjustment, the hydraulic pressure suddenly rises or makes an abnormal noise, you should check whether the oil circuit is blocked or replace the new hydraulic oil in time.

10. Regularly overhaul and maintain the machine, generally once a year for overhaul and comprehensive maintenance. Maintenance includes;

(1) Completely regrind the roll, when the roll diameter is reduced by more than 20mm, it needs to be replaced with a new roll.

(2) Clean the bearings of all parts and replace the new lubricating oil.

(3) Check the wear of bolts, nuts, hydraulic systems and hydraulic components in various parts, and replace them in time if the wear is serious.

(4) Check the wear of the connecting hinge and pin shaft. If the wear is serious and cannot be repaired, replace it with a new one.

(5) Check the rust condition of each plate, clean up the rust, and then repaint the anti-rust paint, and the outer surface can be repainted if necessary.

Section 3 Extrusion of Oil

Oil extrusion is the process of using extrusion equipment to convert crushed, flaking or whole oil into porous extruded materials. Oilseed extruding is mainly used in the puffing and leaching process of soybean raw embryos. It has also been applied to the puffing and leaching process of rapeseed raw embryos, cottonseed raw embryos and rice bran. It can also be used for whole seed oil such as soybeans. For oil extraction.

Extrusion technology began with rice bran extrusion in the mid-1960s, and was tried in soybeans and other oilseeds in the 1970s. At present, great progress has been made in the research and application of oil extrusion puffing leaching process and equipment, and it has been widely used in the oil industry at home and abroad. The types of extruders are increased, their uses are increased, and the output of a single machine is increased. It can be said that the biggest progress in oil production in the past 20 years is the use of oil extrusion, puffing and leaching technology.

1. The purpose and significance of oil extrusion

After the oil is extruded and extruded, the bulk density of the extruded pellets increases (about 50% larger than that of the raw embryo), the oil cell tissue is completely destroyed, the interior has more voids, and the outer surface has more free oil, particle size and The mechanical strength is increased, the permeability of the solvent to the material layer is greatly improved during leaching (the penetration rate is about 4 times higher than that of the green embryo), the leaching rate is increased, and the leaching time is shortened, so the output of the leacher can be increased by 30%-50% %. The wet meal content after leaching of the extruded pellets is only 60% of the wet meal content after the raw embryo leaching (the wet meal content is reduced from 30% to 20%), which can increase the output of the wet meal desolvation equipment and reduce the humidity of the wet meal. The energy consumption required for meal desolvation is greatly reduced. The agglomeration phenomenon of wet meal desolubilization is significantly reduced, which is due to the fact that the vegetable protein causing the agglomeration has been denatured during the expansion process. And because the powder degree of the puffed granules is reduced and the soy hulls have been incorporated into the puffed granules, the amount of powdered meal contained in the mixed steam during wet meal desolubilization is reduced, which reduces the load of powdered meal collection. The solvent during leaching of extruded pellets is about 40% lower than that of raw embryo leaching, about 0.65:1, which makes the mixed oil concentration after leaching reach 30%-35%, which greatly saves the energy consumption of mixed oil evaporation. In addition, the powder degree in the mixed oil is reduced, the load of the mixed oil purification is reduced, and the evaporation effect of the mixed oil and the quality of the leached crude oil are improved. Due to the reduction of the solvent content of the wet meal and the increase of the mixed oil concentration, the solvent loss in the leaching production is significantly reduced. The puffing process inactivates enzymes such as lipoxygenase and phospholipase in the oil, which reduces the acid value of the leached crude oil, reduces the content of non-hydratable phospholipids, and improves the quality of the leached crude oil. Compared with raw embryo leaching, soybean embryo puffing leaching increased the content of phospholipids in crude oil, decreased the content of non-hydratable phospholipids, decreased residual phosphorus content after hydration and degumming of crude oil, increased phospholipid yield and increased lecithin content in phospholipids. In addition, the puffing and leaching process reduces the requirements for crushing and flaking processes, which increases the output of these equipment. However, the larger and firmer extruded pellets will cause the solvent to pass through the material layer too fast, resulting in a significant shortening of the contact time between the pellets and the solvent, thus adversely affecting the leaching effect. From this point of view, the extruded extruded pellets are more suitable for the leaching of the deep layer extractor, and the adverse effect on the shallow layer extractor is particularly significant. In production, these adverse effects can be overcome by reducing the size of the extruded pellets and increasing the circulation rate and amount of the mixed oil in the extractor. Oilseeds are protein denatured during extrusion, so puffing leaching is not suitable for the production of soybean meal for protein extraction.          

2. Oil extrusion and puffing equipment

Oil extruding equipment can be divided into three types, one is the extruder (Solvex Expander) that uses low-oil raw embryos, which is the so-called closed-wall extrusion extruder; the other is used for high-oil raw embryos. machine (Hivex extruder), the so-called slotted wall extrusion extruder; one is the Dox extruder for whole or broken oilseeds.

A screw shaft is installed in the cylindrical bore, and the screw blades on the screw shaft are discontinuous and discontinuous. The fixing pin protrudes deep into the inner wall of the cylinder into the space between each helical blade. When working, the combined action of the rotating helical blade and the fixed pin gives the material sufficient kneading. A water addition pipe is installed on the casing wall close to the feed end, and a steam injection pipe is installed on the casing wall close to the discharge end. The function of direct steam injection (steam pressure 0.6-0.8MPa) is to increase moisture and supply heat to soften the material. There is a feeding screw conveyor at the material inlet, a template with slotted holes is installed at the material outlet, and there is a cutter that rotates with the shaft outside the template.

The raw oil embryo is forced and uniformly fed into the extrusion extruder by the screw conveyor, and the raw material in the machine chamber is pushed forward by the screw shaft while being strongly squeezed, so that the density of the material increases continuously. At the same time, due to the friction heating effect between the material and the screw shaft and the inner wall of the machine chamber, the cutting and mixing effect formed by the cooperation of the fixed pin and the screw blade, and the injection of direct steam, the material is fully mixed, heated, pressurized, glued, and gelatinized. This results in changes in organizational structure. The material is extruded from the slot of the template at the end of the extruder in the form of a continuous rope, and is immediately cut into granular materials of a certain size by the cutter. When the material reaches the template in the machine chamber, it is already under the high pressure of 1379kPa-4137kPa, the material temperature is 112.80C, and the moisture content is 10%-13%. At this time, the internal pressure is 13-40 times higher than the air pressure. When the material is squeezed out of the template slot of the extruder, the pressure instantly changes from high pressure to normal pressure, and the pressure suddenly decreases, causing the moisture to quickly evaporate from the material structure. The material is thus subjected to strong expansion, forming expanded collets with numerous tiny pores and surface cracks. The cooking conditions in the extruder can soften and gel the protein of the oilseed, so that the protein can be transformed into a gelatinous substance, which can combine the material particles, and due to the elasticity of the gelatinized protein, the material is in the extruded condition. Porous extruded pellets are formed.

Usually the slot diameter of the template used is 9.5mm-14.3mm. The template can also be replaced as required, and the size and number of slots on the template can be changed. Replacing the template can change the pressure in the machine chamber and the diameter of the extruded pellets, which will also affect the production capacity of the equipment. Of course, the output of the extruder is mainly determined by the diameter of the extruder bore.

The extruder can also be fitted with a conical plug instead of a die plate. The conical plug cooperates with the conical thrust seat installed at the discharge place of the extruder and can move axially. By changing the size of the annular discharge gap, the thickness of the extruded pellets and the pressure in the machine chamber can be changed. The movement of the conical plug and the fixation of its position during operation are controlled by the hydraulic system. The hydraulic system can also make the cone float or automatically adjust and partially compensate the pressure in the extruder and push the cone to a tighter position, thereby keeping the pressure in the bore constant during operation. The cake flow discharged from the conical plug enters the atmosphere and expands to form a porous cake with a thickness of 4mm^-6mm. The structure of the cake is similar to the puffed particles discharged from the template, but the particles are smaller and irregular in shape. It should be noted that automatic adjustment in response to pressure fluctuations within the extruder cannot be achieved using a touch panel.

When a closed-wall extruder is used to extrude raw embryos with high oil content, the oil released during the extrusion process will accumulate in the extruder to produce slow movement of the oil, interfering with the stable state of the operation. Therefore, Anderson International Ltd. developed a slotted wall extrusion machine (1990). The extruder is equipped with a slotted drainage cage on the casing at the discharge end. The oil released from the blank during the extrusion process can be discharged through the gap of the squeeze cage, and the blank is discharged from the end of the extruder. The slot hole of the template or the conical unloader is extruded and extruded, and the extruded pellets containing 20% ​​to 30% of the oil are sent to leaching to extract the oil.

This puffing machine can be used for puffing and leaching of raw embryos of oilseeds such as cottonseed, rapeseed, safflower seed, sunflower seed, peanut kernel, corn germ, etc., thereby replacing the traditional pre-pressing leaching, simplifying the oil-making process of high oil-containing seeds, saving energy The equipment investment is increased, and the oil quality is improved. If the rapeseed is processed by puffing, the phospholipid content of the crude oil is 15×10-5mg/kg, the free fatty acid content is 0.5%, and the chlorophyll is 20×10-6～25×10-5mg/kg. The traditional pre-pressed rapeseed has a phospholipid content of 3 × 10-4-4 × 10-4 mg/kg, a free fatty acid content of 0.6% to 0.8%, and a chlorophyll of 30 × 10-4 to 40 × 10- 4mg/kg. Although the residual oil of the extruded pellets is larger than that of the pre-pressed cake, the leaching rate is significantly better than that of the pre-pressed cake due to the better porosity of the extruded pellets, so it does not affect the residual oil after leaching.

Closed-wall extrusion machines above 8 inches can be equipped with a cage (with interchangeability) to become a slotted-wall extruder, and it only takes 6-7 hours to exchange parts.

Both the closed-wall extruder and the slotted-wall extruder can be equipped with an adjustable pellet feeder instead of a template and a conical plug to become a Dox extruder. The adjustable pellet feeder consists of a rotating cone at the end of the shaft and two side mounted non-rotating (but adjustable) pellet plates. When the material is discharged through the gap composed of the cone and the particle board, it is subjected to extrusion, shearing and puffing. The magnitude of the shear force is affected by the proximity of the tip of the cone to the two pellets, and also by the opening between the two pellets.

One application of the Dox extruder is the pre-press treatment of soybeans. In the process of soybean extrusion, there is no need to inject steam and water, and high shear force can be generated under low moisture conditions to destroy oil cells, so it is also called a dry extruder. Crushed or unbroken oilseeds, with or without preheating, enter the extruder at ambient moisture content or at 10%-14% moisture content. The extrusion process grinds the oil particles and ruptures the oil cells At the same time, the friction and heat make the temperature of the oil powder rise to 121-148.9 °C. When the oil powder is discharged from the extruder, it is squeezed by the high shear force of the pellet discharger and becomes a hot, foamy The powder extrudate in a semi-fluid state, and at the same time the water evaporates rapidly, so that the water content decreases. The materials processed by this extruder can be sent to the screw oil press for oil extraction without drying and cooling. In the process of puffing and sending to the press, the moisture content of the material is reduced to 5% to 6%, which is just suitable for the conditions required by the pressing process. A conventional screw press, with some modifications to its screw shaft structure and rotational speed, can process such materials. Under the same power and pressing to the same residual oil rate, the output can be increased by about 2 to 3 times. Anderson's system is the "Super Soy System" (used to process soybeans).

Another application of the Dox extruder is to add steam to the extruder for wet puffing, replacing the steam wok with the extruder. This puffed material can be sent to an oil press for oil extraction, or it can be processed by a pre-press or conventional extruder for solvent extraction to extract oil. The squeezing cage can also be combined in the Dox extruder to form a Dox-Hivex extruder. Part of the oil released during the puffing process is discharged through the squeezing cage, and the pellets with less oil content can improve the processing capacity of the subsequent equipment. Obviously, conventional steaming and frying equipment cannot achieve this purpose. The application of the Dox extruder here provides a high temperature and instantaneous cooking effect for oilseeds, especially for oilseeds rich in enzymes. This treatment method improves oil quality by inactivating enzymes quickly (expansion time is only 20-30 seconds). quality. The conventional steaming and frying pan usually takes about 45 minutes for the steaming and frying time when the temperature rises slowly. The temperature at which the enzyme is passivated will not be reached until the end of the steaming and frying process, and the enzyme has been activated during the heating and frying process. At the same time, due to the excessive steaming and frying of the material embryos in the steaming and frying pan, some material embryos are inevitably overheated locally, which reduces the oil extraction effect and the quality of crude oil.

3. Oil extrusion puffing leaching process

According to the different types of oil, oil-making process and type of extruder, the extrusion and extruding process of oil is also different. For the puffing of raw oil embryos, it is generally necessary to adjust the moisture and temperature before extrusion and puffing, and the extruded pellets discharged from the extruder have high temperature and humidity, and are soft and brittle, which must be dried and dried. Cooling can make its temperature, moisture and hardness meet the requirements of solvent leaching to extract oil. For example, for soybeans with low oil content, the thickness of the raw embryo is 0.3-0.5mm, and after drying, the moisture content in the machine reaches 10%-11%, and the temperature is 60-65°C. The temperature of the pellets out of the extruder is 100-110 ℃, and the moisture content is 10%-12%. After drying, about 2% of the moisture is removed, so that the moisture content reaches 8%-10%, and the temperature is about 50 ℃. For cottonseeds with high oil content, the thickness of the raw embryo is 0.2-0.3mm, the moisture in the machine is 6%-8%, and the moisture in the machine is 10%-12%.

The first oil leached by extrusion is rice bran. Rice bran contains 16%-22% of oil and has a large powder. The permeability of the material layer during solvent leaching is poor, and the excess solvent contained in the wet meal is difficult to dissolve. Rice bran also contains a large amount of lipase, which can easily decompose the oil in rice bran, resulting in an increase in the acid value of rice bran oil. Rice bran extrusion and puffing can not only passivate lipase, but also convert rice bran into porous puffed particles to improve the leaching production effect and product quality.

For example, the domestic oil extrusion extruder YJP250, the screw diameter is 250mm, the screw length is 3252mm, the spindle speed is 268r/min, the expansion coefficient is 1:1.2-1.4, the output is 350-500t/24h (soybean raw embryo), and the power is 90-110kW. An 8-inch extruder produced by Anderson International Co., Ltd., with a speed of 330r/min and an output of 300t/24h soybean embryos), equipped with 75 horsepower (HP)', motor. The current largest extruder is the 12-inch Solvex extruder produced by Anderson International Ltd., which can process 1,700t of soybeans per day.