Soybean oil is main edible oil in market. In oil extraction plant/mill, crude soybean oil can be extracted after pre-treatment ( cleaning, selecting, rolling flake, expansion or press). The processes involved in soybean oil leaching process include crude oil extraction, wet meal desolventizing, mixed oil evaporation and stripping, and tail gas recovery.
The method of extraction is based on the principle of the solvent react with the raw material，then dissolve the oil and grease of the raw material.
The Advantages of Extraction Technology are as follows:
1. The oil production efficiency is high; the residue oil rate in meal is less than 1%, and the high quality of meal is conducive to the comprehensive utilization of meal.
2. Easy to achieve mass production and production automation.
3. The whole production line takes closed processing with low operating temperature,and good production environment.
4. Suitable for all kinds of oil plants extraction.
The main machine is extractor, such as rotocel ectractor.
The discharged meal contains 25% to 35% solvent, in order to recover the solvent and obtain better quality meal, the meal can be heated to evaporate the solvent .
The meal from the extractor contains 25% ~ 35% solvent, in order to recover solvent and obtain good quality meal, the solvent can be heated to remove.
Desolubility drying equipment: usually using high material layer steam drying machine to remove the solvent and drying the prepress cake, and it is advisable to use D .T desolventizer-toaster for the soybean cake desolventizing.
Main equipment are: scraper conveyor, desolventizer toaster, horizontal drier, liquid foam trapper.
The miscella (a mixture of oil and solvent) that is pumped out of the extractor must be treated to separate the oil from the solvent. The method of separation is to use the different boiling point of oil and solvent, first to evaporate the oil, and to make the most of the solvent vaporize and to separate from the oil. Then, according to the different volatile of solvent and oil, distillate(stripping) thick miscella by steam, distillate out solvent residue from crude oil, to obtain low solvent content crude leaching oil, but before the evaporation and stripping, "pretreatment" process of miscella is required, to remove the solid meal foam and colloidal substances in it, create conditions for the miscellal component separation.
Main Equipment are filter, miscella tank, 1stevaporator (long tube evaporator), 2nd evaporator, stripper, crude oil tank, crude oil pump.
The solvent gas produced by the equipment in leaching workshop needs to be condensed and recycled into the condenser. The quality of the condensing effect not only affects the exhaust recovery load, but also affects the production cost and safety of the factory, so it must be taken seriously.
The air contains a lot of solvent vapor. Before discharging, the solvent is required to be recovered.
Part of solvent of condensate can be recovered, but there is still some immature gas, containing a small amount of solvent, which should be recycled before discharging the waste gas.
The common methods are paraffin oil exhaust recovery method and cryogenic freezing method.
Main equipment: absorption column, desorption column, paraffin heater, last condenser.
Steam(pressure 6Kgf/cm2): <300kg/T
Meal moisture10.5-13 %( can be controlled)
Oil residue in meal<1%
Solvent residue in meal<600PPM
Solvent residue in oil<300PPM