Rice Bran Pretreatment & Expanding Workshop
rice bran→rice bran cleaning→rice bran and broken rice separation→conditioning→expanding→drying and cooling→to solvent extraction workshop
1. Rice Bran Cleaning
First, the rice bran enters the cleaning screen in the rice bran oil plant to remove the impurities. Then roller magnetic separator is adopted to remove the iron impurities. Iron impurities can cause damage to the expander and influence the expansion effect.
2. Rice Bran and Broken Rice Separation
The rice bran goes through rice bran & broken rice separator to remove broken rice and whole rice. This process can ensure normal operation of the rice bran oil processing plant, reduce residual oil rate in the meal, reduce solvent consumption and increase the oil yield. The broken rice can be used for sugar and liquor making.
3. Rice Bran Conditioning
Conditioning is to preheat the rice bran and adjust the moisture content. The moisture content can decide the elasticity and plasticity of the expanded materials. Preheating can improve the expansion effect and increase the capacity. The rice bran enters the conditioner for conditioning process in the rice bran oil production line.
4. Rice bran Expanding
The conditioned rice bran enters the rice bran expander and direct steam is injected. By the rotating of the main worm shaft, the materials are extruded, heated, sheared and kneaded, the temperature and pressure increases and the materials are extruded out. With the sudden decrease of the pressure, the moisture evaporates rapidly and the materials expand and form the porous pellets.
Adopting expansion technology in the rice bran oil production line can increase extraction efficiency, reduce residual oil rate in the meal, increase the capacity of the oil extractor, reduce power consumption and improve the quality of the extracted rice bran oil.
5. Drying and Cooling
The expanded materials have high temperature and high moisture content and shall be dried and cooled to meet the requirement of the extraction process. Usually, chain dryer or pneumatic dryer is adopted in the rice bran oil processing plant for the drying and cooling of expanded rice bran.
Rice Bran Oil Solvent Extraction Workshop
rice bran→solvent extraction→wet meal desolventizing→evaporating and stripping→solvent recovery→crude extracted rice bran oil
1. Solvent Extraction
The expanded rice bran enters the rotocel extractor or loop extractor in the rice bran oil extraction plant to extract the oil with a solvent. The drained wet meal is sent to the DTDC desolventizer by the wet meal scraper conveyor. The thick miscella is pumped into the miscella centrifugal separator and continuous miscella filter to remove the solid impurities, and finally pumped into the miscella holding tank.
2. Wet Meal Desolventizing
The solvent containing wet meal discharged from the oil extractor enters the DTDC desolventizer to separate the solvent from the meal. The wet meal first enters the predesolventizing layer of the desolventizer to remove part of the solvent heated by indirect steam. After that, the meal enters the desolventizing layer to remove the rest solvent distilled by direct steam. The desolventized meal contains a large amount of water and falls into the drying later to remove water. The dried meal enters the cooling layer to lower down the temperature and is then sent to the meal storehouse for packaging. The mixed vapor from the desolventizer in the rice bran oil plant enters the shell pass of first long tube evaporator as the heat source.
3. Evaporating and Stripping
The miscella from the miscella holding tank enters the first evaporator, the second evaporator and the disk stripping column in the rice ban oil plant to separate solvent and crude rice bran oil. The solvent vapor enters the condensing system. The crude oil enters the crude oil holding tank. The rice bran oil extraction plant adopts negative pressure evaporation technology, saving steam consumption and the extracted crude oil has good quality.
4. Solvent Recovery
The solvent vapor in the rice bran oil extraction plant enters the condensing system. The non-condensing vapor from the evaporating condenser and stripping condenser is pumped out by the steam jet pump and pumped into the shell pass of the first evaporator, resulting in the negative pressure of the evaporating system.
The condensate from the condensing system enters the water separator. The solvent separated enters the solvent holding tank for recycling use. The water separated enters the boiling tank to strip the residual solvent by direct steam.
The solvent-carrying air in the rice bran oil extraction plant enters the vent gas condenser. The vent gas from the vent gas condenser enters the mineral oil system in the rice bran oil plant. The unabsorbed vent gas is vented into the atmosphere.
Crude Rice Bran Oil Refining Workshop
crude rice bran oil→phosphoric acid degumming, water washing and continuous drying→dewaxing→decolorization→physical deacidification and deodorization→defatting→finished rice bran oil
1. Phosphoric Acid Degumming, Water Washing and Continuous Drying
The crude rice bran oil from the extraction workshop is pumped into the crude oil filter to remove the residual impurities and then enters the heat exchanger and heater to be heated to the desired temperature. The heated oil enters the oil acid mixer to mix with phosphoric acid and enters the acidification reactor for reaction. Then the oil enters the alkali liquor mixer to mix with alkali liquor and enters the alkali refining reactor. The alkali refined oil is heated by the alkali refined oil heater and pumped into the degumming centrifuge to separate the soapstocks.
The oil is then mixed with hot water in the oil-water mixer and centrifuged by the dehydration centrifuge to remove the wastewater. The oil then enters the vacuum dryer in the rice bran oil refinery plant to remove the water under vacuum.
Crude rice bran oil usually contains 2-4% of wax. Wax can reduce refining yield, increase clay consumption and cause the opacity of rice bran oil. The dried oil enters the heat exchanger to be cooled and then enters the crystallizer in the rice bran oil production line for cooling crystallization and then is filtered to remove the wax. The wax can be refined for industrial use.
The dewaxed oil enters the heat exchanger and dewaxed oil heater and then is pumped into the premixing tank to be mixed with bleaching clay. The mixture enters the decolorization tower for bleaching process under vacuum. The pigment and residual mucilaginous impurities in the oil are adsorbed on the clay. The bleached oil is pumped into the leaf vibration filter to remove the waste clay.
4. Physical Deacidification and Deodorization
The bleached oil is pumped into the deaerator to remove the air under vacuum and then pumped into the heat exchanger and heat transfer oil heater to be heated. The oil then enters the physical deacidification tower in the rice bran oil refinery plant to remove free fatty acids by steam distillation. The deacidified oil is heated by the heat transfer oil heater and enters the physical deacid-deodorization tower to remove the free fatty acids thoroughly.
The deodorized oil is pumped into the heat exchanger and cooler to be cooled. After filtered through the fine filter, the oil is sent to the deodorized oil holding tank. The fatty acid enters the fatty acid recycling system.
Rice bran oil contains some solid fat which can crystallize at low temperature to make the oil become turbid. The deacidified and deodorized rice bran oil enters the crystallizer for cooling crystallization. The oil is then filtered to separate the liquid oil and solid fat. Rice bran solid fat can be used for manufacturing margarine and shortening.