(1) General edible oil refining process
1, national standard secondary oil (raw oil requires light color, acid value less than 4 and no pollutants) process flow (Ⅰ)
┌—————————┐
Crude oil → filtration → hydration degumming → vacuum drying → secondary edible oil.
2. National standard secondary oil process (raw oil is inferior crude oil containing pollutants) (2)
┌—————————┐
Crude oil → filtration → alkali refining and deacidification → water washing → vacuum drying → secondary edible oil.
3. National Standard Grade I Oil Process
┌—————————┐
Crude oil → filtration → alkali refining and deacidification → water washing → vacuum drying → secondary edible oil.
(2) Advanced edible oil refining technology
1. Process flow for refining edible oil (including high-grade edible oil and salad oil)
┌-→ dewaxing-┐
Crude oil → filtration → degumming → deacidification → vacuum drying → decoloration → deodorization → filtration → refining edible oil.
2. Process of refining cold meal oil (salad oil)
Crude oil → filtration → degumming → deacidification → vacuum drying → decoloration → deodorization → degreasing → refining cold meal oil.
(3) The refining process of special oil for food.
┌—→ Transesterification →—┐
Crude oil → filtration → degumming → deacidification → dehydration → decoloration → hydrogenation → post-decoloration → fractionation → deodorization.
(1) Soybean oil, peanut oil and sesame oil
Soybean oil, peanut oil and sesame oil are the main oils in China. If the quality of raw materials is good and the oil extraction process is reasonable, the quality of crude oil is good, and the content of free fatty acids is generally lower than 2%, which is easy to refine.
1, crude edible oil refining process (intermittent)
soft water
↓ ┌-→ Desolution →-┑
Filtering crude oil → preheating → hydration → standing and settling → separation → hydrating degummed oil → drying → coarse refining edible oil.
↑ ↓
Oil recovery-oil residue treatment-oil-rich oil residue
↓
Poor oil foot
Operating conditions: impurity content of filtered crude oil is not more than 0.2%, hydration temperature is 90 ~ 95℃, water addition is 3 ~ 3.5 times of crude oil gum content, hydration time is 30 ~ 40 min, settling separation time is 4 h, drying temperature is not lower than 90℃, and operating absolute pressure is 4.0 kPa. If the crude oil is refined and leached, the desolventizing temperature is about 65438 060℃.
2. Refining process of refined edible oil (continuous deacidification, intermittent decoloration and deodorization)
Phosphate lye
↓ ↓
Filtering crude oil → preheating → mixing → ratio of oil to alkali → mixing reaction → soaping → soaping.
↓
Filtering-distillation deodorization-filtering-adsorption decoloration-dehydration-washing-soft water
↓ ↓ ↓ ↑ ↓
Refined edible oil steam waste clay adsorbent wastewater
Operating conditions: the impurity content of the filtered crude oil is not more than 0.2%, the alkali concentration is 18 ~ 22 bé, the excess alkali amount is 10% ~ 25% of the theoretical alkali amount, sometimes 0.05% ~ 0.20% of the oil amount is added first (the concentration is 85%), and the soaping temperature is 70 ~ 80. The adsorption decoloration temperature is 80 ~ 90℃, the absolute operating pressure is 2.5~ 4.0 kPa, the operation time is about 20 min at the decoloration temperature, the added amount of activated clay is 2.5% ~ 5% of the amount of oil, and the filtration temperature does not exceed 70℃ when the clay is separated. P
(2) cottonseed oil
Cottonseed oil is also the main edible oil. However, wool cotton oil contains gossypol (about l%), gum and wax (the content varies with the shell content of oil-making cotton embryo), which is of poor quality and not suitable for direct consumption, and its refining process is also complicated.
1. Raw cotton cleaning and refining process (continued)
Alkaline soft water
↓ ↓
Filtering crude oil → preheating → oil-alkali ratio → mixed reaction → soap removal → washing → dehydration → drying → cotton oil cleaning.
↓ ↓
Soap foot wastewater
Operating conditions: the impurity content of the filtered crude oil is not more than 0.2%, the alkali concentration is 20 ~ 28 bé, the excess alkali is 10% ~ 25% of the theoretical alkali, the soaping temperature is 70 ~ 95℃, and the addition amount of drum washing water is 25 ~ 100 1/h, and the feed rate is 25 ~. L. The amount of washing water is 10% ~ 15% of the oil amount, the dehydration back pressure is 0. 15MPa, the drying temperature is not lower than 90℃, the operating absolute pressure is 4.0kPa, and the filtering temperature of refined oil is not higher than 70℃.
2. Refining process of refined edible oil
Phosphate lye soap foot lye
↓ ↓ ↑ ↓
Filtering crude oil → preheating → mixing → ratio of oil to alkali → mixing reaction → soaping → mixing.
↓
Filtering-distillation deodorization-filtering-adsorption decoloration-dehydration-washing-soap removal
↓ ↓ ↓ ↑ ↓ ↑ ↓
Refined edible oil, steam, waste clay adsorbent, waste water, soft soap residue.
Key points of operation: the operating conditions before alkali refining are the same as those of crude oil refining, and the concentration of alkali liquor after refining is 6 ~ 12 bé, the adding amount is 1% ~ 3% of the oil amount, the refining temperature is 70 ~ 90℃, and the oil back pressure is 0. 15 MPa. The operating conditions of washing, decoloration and deodorization are similar to those of peanut oil refining edible oil. If degreasing is carried out after deodorization, the grade of refined oil is refined cold meal oil (salad oil). The technological process after deodorization is as follows:
→ Soft fat
Deodorizing cotton oil → cooling crystallization → crystal culture → filtration → zeta.
└→ cold meal oil
Operating conditions: cooling crystallization temperature 5 ~ 10℃, temperature difference between cooling water and grease about 5℃, crystallization time 8 ~ 12 h, crystal growth time10 ~12 h.
(3) Rapeseed oil
Rapeseed oil is a semi-drying oil containing erucic acid. Except low erucic acid rapeseed oil, the erucic acid content in other varieties of rapeseed oil is high, accounting for about 26.3% ~ 57% of fatty acid composition. The nutrition of high erucic acid vegetable oil is not as good as that of low erucic acid vegetable oil, but it is especially suitable for industrial oils such as ship lubricating oil and tires. In the process of oil recovery, glucosinolates are hydrolyzed by glucosinolates to form some sulfur-containing compounds and other toxic components, which affect the quality of crude oil. The general crude oil refining process has a low removal rate of sulfide, so edible rapeseed oil should be refined.
1, crude vegetable oil refining process
For the process flow and operating conditions of crude vegetable oil, see crude soybean oil refining.
2, refining rapeseed salad oil refining process (intermittent)
Alkaline solution of oil-rich soapstock → salting out → oil-poor soapstock.
↓ ↑
Filtering cabbage oil → preheating → neutralization → standing and settling → separation → water washing → softened water.
↓
Filtering-distillation deodorization-filtering-adsorption decoloration-dehydration
↓ ↓ ↓ ↑ ↓
Refined vegetable oil steam waste clay adsorbent wastewater
Operating conditions: the initial temperature of alkali refining operation is 30 ~ 35℃, the final temperature is 60 ~ 65℃, the alkali concentration is 16 Bé, the excess alkali content is 0.2% ~ 0.25% of the oil, sodium silicate (concentration is 40 Bé) accounting for 0.5% of the oil is added, the neutralization time is about l h, and the settling and separation time is not long. The washing temperature of alkali refining is 85 ~ 90℃, and the first washing water is dilute saline-alkali water (salt with alkali concentration of 0.4% and oil content of 0.4%), and the addition amount is 15% of oil content. Then wash it with hot water several times until the soap content of alkali refined oil is not more than 50 ppm. When decolorizing, firstly dehydrate in vacuum for 30 min, the temperature is 90℃, and the absolute operating pressure is 4.0kPa, then add activated clay to decolorize, the dosage of clay is 2.5% ~ 3% of the amount of oil, the decolorization temperature is 90 ~ 95℃, the decolorization time is 20 min, then cool to below 70℃ and filter. Decolorization filter oil is heated to 100℃ by vacuum suction deodorizing tank composed of primary and secondary steam jet pumps, and then the cooling water of primary and secondary steam jet pumps and atmospheric condenser is turned on. The deodorizing temperature is not lower than 245℃, the absolute operating pressure is 260 ~ 650 Pa, the water temperature of atmospheric condenser is controlled at about 30℃, the stripping direct steam pressure is 0.2MPa, and the flow rate is 8 ~1.
2. Refined rapeseed salad oil refining process (full continuous)
Phosphate lye
↓ ↓
Filtering crude oil → preheating → mixing → ratio of oil to alkali → mixing reaction → soaping → soaping.
↓
Filtering-distillation deodorization-filtering-adsorption decoloration-drying-dehydration-washing-soft water
↓ ↓ ↓ ↑ ↓
Rapeseed salad oil steam waste clay adsorbent wastewater
Operating conditions: the impurity content of the filtered crude oil is not more than 0.2%, the alkali concentration is 18 ~ 22 bé, the excess alkali amount is 10% ~ 25% of the theoretical alkali amount, sometimes 0.05% ~ 0.20% of the oil amount is added first (the concentration is 85%), and the soaping temperature is 70 ~ 80. Continuous vacuum drying and dehydration at 90 ~ 95℃ and absolute operating pressure of 2.5~ 4.0 kPa. The adsorption decoloration temperature is 105 ~ 100℃, the operating absolute pressure is 2.5~ 4.0 kPa, the operating time at the decoloration temperature is about 30 min, and the addition amount of activated clay is 1% ~ 4% of oil. When the vertical vane filter is used to separate white mud, the filtering temperature should not be lower than 100℃. Phosphorus ≤5 ppm, iron ≤0. 1ppm and copper ≤0.0 1ppm in decolorized oil. The deodorizing temperature is about 240 ~ 260℃, the operating absolute pressure is 260 ~ 650 Pa, the stripping steam is 0.5% ~ 2% of the oil amount, the deodorizing time is 40 ~ 120 min, the citric acid (concentration 5%) is 0.02% ~ 0.04% of the oil amount, and the safe filtration temperature is not higher than 70℃.
(4) Rice bran oil
Rice bran oil belongs to weak semi-drying oil. Because of the high content of lipolytic enzyme in rice bran, high crude oleic acid value and poor quality, it is difficult to refine oil. The refining process of refined rice bran oil is as follows.
Alkaline liquor, oil-rich soapstock, alkali liquor, oil-rich soapstock and soft water.
↓ ↓ ↓ ↑ ↓
Filtering hair bran oil → pretreatment → primary neutralization → separation → secondary neutralization → separation → washing.
↓
Refining rice bran oil-filtration-cooling crystallization-distillation deodorization-filtration-adsorption decoloration-dehydration
↓ ↑ ↓ ↑ ↓
Wax paste, steam, waste clay adsorbent wastewater
Key points of operation: the impurity content of filtered crude oil is not more than 0.2%. Before neutralization, 2% hot water was added for degumming, the degumming temperature was 60~70℃, and the stirring time was 15 minutes. Then, alkaline solution is added for neutralization and deacidification. The concentration of alkali liquor is 18 ~ 24 bé, the excess alkali is 75% of the theoretical alkali, and the alkali liquor is 15min. After reaching the final temperature, add 3%~4% salt solution (concentration 10%, 95℃), continue stirring for 5~ 10min, and then let stand and settle10 ~12 h. After separating the soap residue, wash it at 75~80℃, add 5% salt water (concentration 5 ~ 6 bé, 85℃), and wash it with hot water several times until the residual soap content is ≤50ppm. The decoloration temperature is 95~ 100℃, the absolute pressure is 4.0kPa, the amount of activated clay is about 3% of the oil, and the decoloration time is 30min. Deodorization temperature is 235~250℃, operating absolute pressure is not more than 0.65kPa, stripping steam flow rate is 8 ~16 kg/t h, deodorization time is 6h, cooling dewaxing temperature is 6~ 10℃, crystallization time is 50~70h, and filtration temperature is 15℃.
(5) palm oil refining process
Palm oil is taken from palm pulp, and its fatty acid composition contains 40%~50% saturated acid, of which 80% is palmitic acid, and the unsaturated acid is mainly oleic acid, followed by linoleic acid, which is rich in vitamin A and vitamin E, and its color is dark brown. Due to the decomposition of palm fruit by lipolytic enzymes before harvesting and oil production, as well as the influence of processing methods and storage and transportation conditions, the free fatty acid content of crude palm oil is relatively high, generally around 10%, and the high is above 30%. Palm oil is mainly used to make soap and extract various grades of special oil for food.
Refined palm oil refining process
Alkaline solution of oil-rich soapstock → salting out → oil-poor soapstock.
↓ ↑
Filtering crude palm oil → preheating → neutralization → standing and settling → separation → water washing → soft water.
↓
Filtering-distillation deodorization-filtering-adsorption decoloration-dehydration
↓ ↓ ↓ ↑ ↓
Waste clay adsorbent wastewater from refining palm oil steam
2. Palm oil fractionation refining process
(1) process flow (1)
Soft water and greasy feet
↓ ↑
Filtering crude oil → hydration → separation → cooling crystallization → separation.
↓
Filtration-distillation deodorization-filtration-adsorption decoloration-separation-washing-separation-neutralization-liquid oil-
↓ ↓ ↓ ↑ ↓ ↑ ↓ ↑ │
Liquid palm oil, steam, waste clay adsorbent, waste water, soft water, soap lye.
Filtering-distillation deodorization-filtering-adsorption decoloration-separation-washing-separation-neutralization-solid fat-Φ
↓ ↓ ↓ ↑ ↓ ↑ ↓ ↑
Palm solid fat steam waste clay adsorbent wastewater soft water soap foot lye
(2) Process flow (2)
Phosphoric acid activated clay waste clay water vapor
→ liquid palm oil
Crude palm oil → degumming → adsorption decoloration → filtration → deacidification/deodorization → filtration → cooling crystallization → filtration → zeta.
└→ Palm fat fixation
Key points of operation: the temperature of impurity removal and filtration is not lower than 50℃, and the impurity content of filtered oil is not greater than 0.2%. The initial temperature of intermittent neutralization is 30 ~ 35℃, the final temperature is 60 ~ 65℃, the alkali concentration is 16 ~ 18 bé, the excess alkali accounts for 0.2% ~ 0.3% of the oil, and the neutralization time is about l h；; The concentration of continuous neutralization alkali liquor is 20 ~ 28 bé, the excess alkali accounts for 10% ~ 25% of the theoretical alkali quantity, the soaping temperature is 70 ~ 95℃, the drum washing water quantity is 20 ~ 25L/h, and the oil inlet pressure is 0. L ~ 0.3 MPa, oil back pressure is 0. L ~ 0. 15 MPa. The decoloration temperature of solid oil and liquid oil is105 ~10℃, the absolute operating pressure is 2.5 ~ 4.0 kPa, the time is 15min, and the amount of activated clay is 3% of the oil. The temperature of distillation deacidification and deodorization is 240 ~ 250℃, the absolute pressure of operation is 0.2 ~ 0.4 kPa, and the time is 80 ~ 100 min. The initial temperature of cooling crystallization is 70 ~ 80℃, and the final temperature after 24 hours is 20℃. The temperature difference between cooling water and oil is 5 ~ 8℃, so the filtration pressure should not be too high during separation.
(6) Palm kernel oil and coconut oil
Palm kernel oil and coconut oil belong to non-drying oil. The fatty acid composition is mainly lauric acid (accounting for 45% ~ 5L% of the fatty acid composition), followed by myristic acid (accounting for about 13% ~ 25%), with low gum content, which is especially suitable for physical refining and deacidification. Palm kernel oil and coconut oil are divided into soap grade and edible grade. The refining process of refined edible oil is as follows.
Phosphate clay
↓ ↓
Crude oil → dry degumming → filtration → deacidification/deodorization → fine filtration → refined oil.
↓ ↑
Waste clay water vapor
Key points of operation: The main purpose of dry degumming is to remove rubber impurities and trace metal ions. When degumming, 85% phosphoric acid is added, accounting for 0. 1% ~ 0.2% of the oil content, and the mixture is stirred for 15 minutes, then activated clay with 2% ~ 3% of the oil content is added for decolorization, and further adsorption degumming is carried out. The working temperature is 105 ~ 16544. The reaction time is 10 ~ 15 min, the temperature for filtering and separating white mud is not higher than 70℃, and the pretreatment oil requires P≤5 ppm, Fe≤0. 1 ppm and Cu≤0.0 1ppm. The temperature of distillation deacidification and deodorization is 240 ~ 250℃, the absolute pressure of operation is 0.2 ~ 0.4 kPa, the amount of stripping steam accounts for 1% ~ 4% of the oil amount, and the time of deacidification and deodorization is 40 ~ 100 min.
(7) Sunflower seed oil
Sunflower seed oil is one of the main oil sources in northern China. Rich in linoleic acid (accounting for 54% ~ 70% of total fatty acids) and oleic acid (accounting for about 39%), it has high nutritional value. However, crude oil contains a small amount of wax (about 0. 10%) and oxyacid, which affects the quality and storage stability. There are two grades of sunflower seed oil in the market: crude edible oil and refined edible oil.
1. Refining technology of sunflower seed crude oil
Alkaline soft water
↓ ┌←Al(SO4) ↓
Filtering mallow oil → cooling → alkalization → separation → washing → dehydration → drying → crude refining of sunflower seed oil.
↓ ↓
Soap wax wastewater
Key points of operation: the operation requirements of filtration and impurity removal are the same as those of the previous process. The alkalization operation temperature is about 9℃, the concentration of alkali liquor is 15 Bé, and the addition amount is about 1.36% of the oil amount, and the addition amount of Al2(SO4)3 (aqueous solution concentration is 14% ~ 24%) accounts for 0.25% ~ 0.5% of the oil amount.
2. Process flow of refining sunflower seed oil:
Phosphate lye
↓ ↓
Filtering crude oil → preheating → mixing → ratio of oil to alkali → mixing reaction → soaping → soaping.
↓
Wax paste-filtration-cooling crystallization-distillation deodorization-filtration-adsorption decoloration-drying-dehydration-washing-soft water
↓ ↓ ↓ ↑ ↓
Sunflower salad oil steam waste clay adsorbent wastewater
Key points of operation: refer to the refining process and degreasing process and operation of vegetable oil salad oil.
(8) safflower seed oil and corn germ oil
The fatty acid composition of safflower seed oil and corn germ oil is regular, and the contents of oleic acid and linoleic acid are high (oleic acid accounts for about 13%~49%, linoleic acid accounts for about 34%~76%), which is an oil with high nutritional value and can be refined into "nutritional oil". The refining process is as follows. Please refer to vegetable oil salad oil refining for operation points.
Phosphate lye
↓ ↓
Filtering crude oil → preheating → mixing → ratio of oil to alkali → mixing reaction → soaping → soaping.
↓
Wax paste-filtration-cooling crystallization-distillation deodorization-filtration-adsorption decoloration-drying-dehydration-washing-soft water
↓ ↓ ↓ ↑ ↓
Salad oil steam waste clay adsorbent wastewater
(9) Linseed oil
Linseed oil is made from linseed and belongs to drying oil. The linolenic acid content in its fatty acid composition is as high as 44%~6 1%, which has good drying property and is an important raw material for paint, ink and coating industry. Linseed oil has a high gum content, many of which are non-hydrophilic. Conventional hydration methods can't meet the degumming process requirements, and additives need to be added for degumming. The refining process of industrial linseed oil is as follows.
Na _ 3PO _ 4 solution lye soap foot
↓ ↓ ↑
Filtering crude oil → preheating → hydration → neutralization → separation → washing → soft water.
↓
Crude refined linseed oil-filtration-cooling crystallization-filtration-drying-separation
↓ ↓ ↓
Wax paste filter residue wastewater
Key points of operation: the hydration operation temperature is 25~30℃, the addition amount of trisodium phosphate is 0.28%~0.3% of the oil amount (prepared into 1.3% aqueous solution), after stirring for 30 minutes, alkali liquor is added for neutralization and deacidification, the alkali liquor concentration is 20 Bé, and the excess alkali accounts for 0.06% ~ 0.1of the oil amount. The washing operation temperature is about 85℃, the washing water accounts for 10%~ 15% of the oil amount, and the wastewater sedimentation and separation time is not less than 2 hours. The vacuum dehydration temperature is about 120℃ and the operating pressure is lower than 5 kPa. After drying, the oil temperature is cooled to 30~35℃, and the filtered oil is filtered for the first time. The filtered oil is cooled to 20~25℃ for crystallization for about 32 hours, and then the wax is removed by filtration, and the filtration pressure is not higher than 0. 1.2MPa.
(10) Castor oil
Castor oil is non-drying oil containing hydroxy acid. The content of ricinoleic acid accounts for about 87. 1%~90.4% of the fatty acid composition, which is widely used in aviation, precision instruments, medicine, coatings, plasticizers, emulsifiers, insulating oils, textiles and tanning industries. Because of its structural characteristics, the conventional hydration process is not suitable for degumming, and light alkali is often used for degumming. The refining process of refined castor oil is as follows.
Dilute lye soap soft water
↓ ↑ ↓
Filtering crude oil → preheating → neutralization → separation → washing → separation → wastewater.
↓
Refined castor oil-filtration-distillation deodorization-filtration-adsorption decoloration-drying
↓ ↓ ↑
Water vapor waste clay adsorbent
Key points of operation: the operating temperature of dilute alkali neutralization is 25~35℃, the concentration and dosage of alkali liquor are shown in Table 8- 1, the neutralization stirring time is about 15min, and the final temperature is about 90℃. After neutralization, add soft water-soluble soap with oil content of 25%, let stand for 15~20min, and then transfer the middle and lower soap aqueous solution to a soap tank for recycling. The decoloring operation temperature is about 85℃, the operating pressure is 2.5~4.0kPa, and the decoloring time is 20min. The amount of activated clay accounts for about 4% of the oil. The operating temperature of deodorization is 175~ 180℃, the operating pressure is 0.3~0.6kPa, the stripping steam flux is 8 ~16 kg/t h, and the deodorization time is about 5 hours.
Table 7-4 Relationship between acid value of castor oil and alkali dosage and alkali concentration; Total oleic acid value; Consumption of solid caustic soda (percentage of oil); The alkali liquor concentration (bé) is 0.44 ~ 54 ~ 50.45 ~ 0.505 ~ 65 ~ 60.50 ~ 0.606 ~ 87.5 ~ 8.50.70 ~ 0.806 ~ 81~120. The above 438+0.20 ~1.406 ~ 815 depends on the acid value 10 ~ 12.