An edible oil refining plant normally includes neutralization, bleaching, deodorization and vacuum auxiliary sections:
Neutralization section
Crude oil from tank area is sent to crude oil tank in workshop by pump, after accurate measurement with mass flow meter enters crude filter, remove bigger mechanical impurities in filtered crude oil,after exchanging heat between filtered crude oil with deodorization oil, heat with crude oil heater and mix with phosphoric acid whose concentration is 85% in oil acid mixer, the addition quantity of phosphoric acid is added at a certain quantity with metering pump according to processing capacity and crude oil quality.After mixing of oil and acid, enter acidification reaction tank to reduce the content of nonhydratable phospholipid,then enter oil alkali multiple effect mixer, after good mixing of oil and lye at certain concentration pumped by metering pump, enter neutralization tank, utilize liquid level automatic control in neutralization tank to adjust the reaction time, oil after reacting in reaction tank is pumped into plate heat exchanger to heat to about 90℃, and enters centrifuge to remove soap-stock; alkali refining adopts middle temperature reaction, high temperature separation, not only reduce saponification of neutral oil, but also improve separation effect of centrifuge and refining yield; the oil after removing soap-stock with first centrifuge enters oil water multiple effect mixer, which adopts frequency control, to prevent mixing strength is too big, oil and water emulsification,oil after water washing enters the second centrifuge for centrifugal dehydration, control dehydration temperature at about 90℃, dehydrated oil is heated to about 100℃ with plate heater, and then enters vacuum dryer for drying and dehydration, drying temperature is adjustable through automatic control, dehydrated oil enters bleaching premixing tank directly, soap-stock removed from soap-stock removal centrifuge is pumped into outdoor soap-stock temporary storage tank by soap-stock pump.Water separated by water washing centrifuge enters combined water separation tank, separated oil is pumped into crude oil tank in workshop, separated water is discharged to outdoor water seal pool through indoor trench to recycle residual oil in water.
Bleaching section
Exchange heat between neutralized oil and deodorization oil, then heat to 105－115℃ with plate heat exchanger, enters premixing tank to mix with bleaching clay( 1-3% of oil weight),then overflow into bleaching tower(bleaching temperature and time is adjustable by automatic control),then use special oil slurry pump to pump it into two alternate horizontal filters to filter, filtered oil enters dewaxing section after through polishing filters,waste bleaching clay is discharged to waste bleaching clay room.
Deodorization section
Filtered bleaching oil enters deaerator tank directly to remove oxygen in oil, deoxygenized oil quality exchange heat with deodorization oil, and heat with heat conduction oil heater to 250℃,then oil goes through filler part by the methods of falling film countercurrent stripping, stripping capacity is high, splash is little, fatty acid can be removed rapidly to avoid hydrolysis happen; oil flows into board part through pipe, direct steam in board part erupt from oil with the shape of bubble, and contact oil for stripping again, reduce boiling point of odor matters through high vacuumin board part, and through distillation of superheated steam to reach deodorization purpose, and delay for thermal bleaching, deodorization oil is discharged from the bottom of deodorization tower, this process takes about 65~80min. Deodorization oil is drawn with shield pump through oil-oil heat exchanger, bleaching oil heat exchanger, crude oil heater,then finished oil cooler to cool to below 40℃,finally enters finished oil storage tank through polishing filter.
Vacuum auxiliary section
Drying and bleaching vacuum system adopt condenser and water circulating vacuum pump types,circulating cooling water which is cooled by frozen water in condenser can be recycled. This system do not use steam, only consume little power, less running machines, maintenance is convenient.
Deodorization vacuum system adopts combined types of steam jet vacuum pump, condenser and water circulating vacuum pump, steam jet pump adopts 9 bar steam, save energy, reduce steam consumption, cooling medium of deodorization vacuum system adopts 25℃∽28℃ cooling water, cooling water can be recycled after cooling by cooling tower.
Process technical features
- The whole plant adopts waste heat utilization technology. In every section, set energy-saving heat exchanger, finished oil at high temperature exchanger heat with bleaching oil, dry oil and crude oil in proper order from high to low according to different process temperatures, can make maximum use of waste heat of deodorization finished oil,reduce steam consumption. All steam condensate water of heating equipment is recycled into hot water tank for reuse.
- Drying of water washing oil adopts vacuum drying technology, compare with traditional technology, not only reduce steam consumption, but also prevent oil from contacting air,reduce oil oxygenation efficiency, keep the maximum inherent nutrition value in oil.
- When blow bleaching clay,design bad smell catching device, use circulating water cooling to catch bad smell of blowing steam, remove bad smell pollution, meet environmental requirement.
- Set self-spraying device in waste bleaching clay room, spray cooling water when discharging cake from filter, ensure effective cooling of bleaching clay, avoid spontaneous combustion of bleaching clay, play a role safe production.
- Full automatic production in the whole plant, temperature,pressure and liquid level and other key control points are computer display, automatic control.