Cottonseed oil, that is, the oil extracted from cotton seeds, is divided into pressed cottonseed oil, extracted cottonseed oil, transgenic cottonseed oil, cottonseed crude oil, and finished cottonseed oil.It is darker red than other oils. It can be refined for human consumption and contains a lot of essentialfatty acidIt is most suitable to be mixed with animal fat.But eatCrude cottonseed oilCan causeSpermatogenic cellDamage, resulting in infertility.
English alias: cotton;LIPEX 109;cottonoil;nci-c50168;cottondoil;COTTONSEED OIL;COTTONSEEDOIL,NF;cottonseedoilacid;Baumwoellsamenoel;OIL OF COTTON SEED
Physical and chemical properties
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Flash point: 113 C
Storage condition: 2-8 ℃
Stability: stable, flammable, strong oxidant incompatible, sensitive to light and heat.
Relevant definitions
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Pressed cottonseed oil: The oil made from cottonseed by direct pressing.
Extracted cottonseed oil: the oil produced from cottonseed by the extraction process.
GM cottonseed oil: Oil made from GM cottonseed.
Cottonseed crude oil: cottonseed oil that has not been treated and cannot be directly used for human consumption.
Finished cottonseed oil: It is the cottonseed oil that is directly used for human consumption after being treated and meets the quality indicators and health requirements of the national standard refined oil.
Basic ingredients
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Refined cottonseed oil is generally orange yellow or brown, and containspalmitic acid21.6-24.8%，stearic acid1.9-2.4%, arachidic acid 0-0.1%,oleic acid18.0-30.7%，linoleic acid44.9-55.0%. The refined cottonseed oil can remove gossypol and other toxic substances and can be used for human consumption.The cotton clear oil contains a large amount of essential fatty acids for human body, which is most suitable to be mixed with animal fat, because the content of linoleic acid in cotton clear oil is particularly high, which can effectively inhibit the rise of cholesterol in the blood and maintain human health.The absorption rate of cotton clear oil by human body is 98%.
Manufacturing process
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Stir fry seeds
Generally, put 1/4~1/3 of the capacity in the pot, stir it evenly, turn it over frequently, and do not use too much firepower to avoid shell charring.After fryingcottonseedFlatten in the trough and use a stick barrel to make hot steam dissipate, which is convenient for screening and cleaning after cooling.
Sieving
Remove soil and impurities with manual screen or fixed screen.
Grinding
Cottonseed oil
When grinding, the blanking should be less, even without interruption, and the speed of the grinder should be reasonably fast to make the cottonseed easy to break.
water
Spray water along with the roller ring groove. When grinding, spray water and turn over seeds at the same time to make the billet draft even and grind uniformly for about 20 minutes until the fine billet is not clustered.
Steamed billet
Powder billet pouringSteam drumIt shall be leveled by hand to ensure uniform ventilation in the steam drum and consistent temperature and moisture of the billet.The bottom of the drum is round, like the back of a shapeless skillet. It is heated evenly. The water level of the steaming pot is consistent. The distance between the bottom of the drum and the water surface should be more than 16cm. The fire should be even.
Bread cake
Cake wrapping should be decentralized, fast, flat and tight packed, and concentrated and fast pressed.Single ring pancake is about 2cm thick after pressing. The time should be shortened as far as possible to prevent heat loss in the billet.
press
During the initial pressing, the cake shall be aligned, and the distance between circles shall be adjusted to avoid unevenness of the cake.When sharpening, the oil flow shall not form a line.When the oil line is broken, empty press for another 2 hours before loosening.
Clarification and filtration
SqueezedCrude oilThere are many impurities.It should be cooled quickly and filtered after standing for a period of time to avoid color deepening and increase refining loss.
In China, farmers in cotton producing areas have suffered from testicular atrophy and infertility due to long-term consumption of crude cottonseed oil.Gossypol, a phenolic glycoside, is a powerful spermicide. Gossypol is toxic to the liver, blood vessels, intestines and nervous system.Free gossypol can also affect most menHypolibido。
2. Refined cottonseed oil with gossypol removed is edible and will not cause the above adverse conditions.According to the national health standard, the gossypol content in oil is less than 0.02%.When the gossypol in cotton oil is not higher than 0.02%, it has no effect on human body.
3. The cottonseed oil cotton clear oil contains a large amount of essential fatty acids for human body, which is best mixed with animal fat, because the content of linoleic acid in cotton clear oil is particularly high, which can effectively inhibit the rise of cholesterol in the blood and maintain human health.
Refining method
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Cotton seed oil is also the mainEdible oil。But wool cotton oil containsgossypol(the content is about 1%), gum and wax (the content varies according to the shell content of the oilcotton embryo), which are of poor quality and not suitable for direct consumption, and their refining process is also complex.
1. Refining process flow of crude cotton clear oil (continuous)
1. Refining process flow of crude cotton clear oil (continuous)
Operating conditions: the impurity content of filtered crude oil is not more than 0.2%, the concentration of alkali liquor is 20~28 ° B é, the excess alkali is 10%~25% of the theoretical alkali, the desoaping temperature is 70~95 ℃, the amount of drum washing water added is 25~1001/h, the oil inlet pressure is 0. l~0.3 MPa, the oil outlet back pressure is 0.1~0.3 MPa, the washing temperature is 85~90 ℃, the amount of washing water added is 10%~15% of the oil amount, and the dehydration back pressure is 0.15 MPa,The drying temperature shall not be lower than 90 ℃, the absolute operating pressure shall be 4.0kPa, and the filtration temperature of product oil shall not be higher than 70 ℃.
Key points of operation: the operating conditions before alkali refining are the same as those of crude oil refining. The concentration of alkali liquor for re refining is 6~12 ° B é, the addition amount is 1%~3% of the oil amount, the re refining temperature is 70~90 ℃, and the oil outlet back pressure is 0.15 MPa.The operating conditions of washing, decoloring and deodorization are similar to those of peanut oil refined edible oil.If degreasing is carried out after deodorization, the product oil is refined cold meal oil (salad oil).The process flow after deodorization process is as follows:
Development of soapstock after cottonseed oil refining
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In the process of cottonseed oil processing, if 10% soap residue is produced, 100000 tons of cottonseed oil soap residue will be produced in the country every year, which is very rich in resources. Most cottonseed oil processing plants discard soap residue as waste, which is not well used, causing huge pollution and waste.How to turn these resources into treasure and make them a booster to expand the cotton industry chain has become an urgent problem to be solved in the cottonseed processing industry.The treatment of cottonseed oil soapstock can not only solve the problem of environmental pollution caused by cottonseed oil soapstock, but also bring certain economic benefits to enterprises.
The soap residue of cottonseed oil is generated in the process of alkali refining. The main role of alkali refining is to remove free fatty acids, phospholipids, proteins, mucus, impurities, pigments, metal ions in cottonseed oil, as well as the unique gossypol in cottonseed oil.Soap feet are composed differently with different processes and raw materials, generally containing 60%~75% soap (dry basis) and 25%~40% neutral oil (dry basis).Among them, gossypol is inherent in cottonseed oil. It is the main pigment in cottonseed, accounting for 20%~40% of the total pigment, and 0.15%~1.8% of the total weight of cottonseed. During alkali refining, all gossypol in cottonseed oil enters into the soap foot, which is easily converted into various dark compounds under alkaline conditions, making the soap foot dark brown.
In view of the main components and characteristics of cottonseed oil soapstock, its development and utilization at home and abroad are mainly focused on the following aspects:
phospholipid
Phospholipids are natural lipid compounds with important physiological functionssurface active agent And emulsifiers, with high nutritional value, can be widely used in food, medicine, cosmetics, leather, fiber, dyeing, feed and other aspects.In the food industry, it is an important additive and emulsifier, which can nourish and strengthen the bodyCardiovascular diseaseEffective;It can be used as a preservative for fruits and an additive for feed;In rubber industry, phospholipid can be used as softener and foaming agent.
Phospholipids are componentsHuman cellsIt is an important component of, usually composed of glycerin, fatty acid, choline and other substances. Phospholipids in oil are generally combined with proteins, sugars, sterols, tocopherols, biotins and other substances to form complex complexes. The bound phospholipids in cottonseed oil are up to 90%.The content of phospholipid in cottonseed oil is high, and the content of phospholipid in cottonseed wool sleeve is 0.7%~2.0%, which is second only to soybean.It is composed of fatty acids, choline and other substances. Phospholipids in oil plants are generally combined with proteins, sugars, sterols, tocopherols, biotins and other substances to form complex complexes. The bound phospholipids in cottonseed oil are up to 90%.The content of phospholipids in cottonseed oil is highCrude oilThe phospholipid content in soybean is 0.7%~2.0%, second only to soybean.
Phospholipids produced from soapstock generally include concentrated phospholipids, liquid phospholipids, bleached liquid phospholipids, deoiled phospholipids, separated phospholipids, modified phospholipids and other products.commonphospholipidProcessing technology:
With the prominent problem of energy shortage in the world and people's increasing attention to environmental protection, it is urgent to develop and research biodiesel, a green and environment-friendly fuel, to replace the constantly exhausted oil resources. It is not only one of the effective ways to develop new energy, but also can make full use of leftovers from vegetable oil plants and turn waste into treasure,It can produce huge social and economic benefits.The United States, Canada, Brazil, Japan, Australia, India and other countries are actively developing this industry.In 2001, the output of biodiesel in EU countries exceeded 1 million to develop and research biodiesel in China, which has great significance and broad application prospects.
biodieselIt is a transparent liquid fuel whose color is basically the same as that of diesel oil, which is compounded with chemical raw materials after the modification of soap feet, a leftover from animal, vegetable oil or refined edible oil.The carbon content and molecular weight of biodiesel are close to those of diesel. According to the principle of similar solubility, biodiesel has excellent compatibility with diesel.The antiknock performance of biodiesel is better than that of petrochemical diesel.High oxygen content, less oxygen required during combustion than petrochemical diesel, and better combustion and ignition performance than petrochemical diesel.It is renewable energy with good biodegradability and good health and environmental protection performance.The flash point of biodiesel is higher than that of petrochemical diesel, which is conducive to safe transportation and storage.
The main processes for producing biodiesel from soapstock are as follows:
The viscosity of biodiesel prepared from vegetable oil is close to that of diesel oil. The cetane number of methyl ester of waste cottonseed oil is much higher than that of diesel oil, and the flash point reaches 166 ° C, ensuring safety.Therefore, the physical and chemical properties of biodiesel and diesel are very similar, which has the potential to replace diesel.
Due to esterificationFatty acid methyl esterThe technological process of is complex, and the catalyst is difficult to be recycled. Researchers are committed to the development and research of new processes. For example, the refining process after the reaction can be simplified by using enzymatic catalytic reaction;The "engineering microalgae" (i.e. microalgae constructed by genetic engineering technology) technology developed by American scientists has also opened up a new way for diesel production.
fatty acid
The extraction of fatty acids from soap feet can also turn waste into treasure and create huge economic benefits.With the continuous development of modern industry, fatty acid has become an important basic chemical raw material in the world's industrial products. Its consumption in plastics, surfactants, textiles, leather and other fields has shown a steady growth trend year by year. In particular, the market demand for synthetic products and various derivatives based on fatty acid has exceeded more than 2000, driving the prosperity of the entire fatty acid industry.The demand for fatty acid is quite large at home and abroad, and its market prospect is also very broad.In recent years, the consumption of fatty acid in the world is 3 million tons, and the demand for domestic fatty acid products has also increased rapidly. The demand for industrial oleic acid was 655.3 tons in 1994, and increased to 16000 tons in 1999. The demand for industrial stearic acid was 314000 tons in 1999. The rapid growth of demand has caused a tight demand for domestic fatty acid products, and the price of products has risen. Every year, a large number of imports are needed to supplement the domestic market.
Cottonseed oil fatty acidsThe content of linoleic acid in the composition is more than 50%. Compared with other oil crops, the content of palmitic acid in cottonseed oil is 24.7%
There are three common methods to produce fatty acid from soap foot, namely acidification hydrolysis, saponification acidolysis and hydrolysis acidification.In saponification acidolysis, the saponification depth of oil and fat can reach 99%, the equipment is simple, the operation is convenient, the production cycle is short, and the quality and output are better than other methods, but the acid and alkali consumption is large, the energy consumption is high, and the three wastes are serious, which is only applicable to small-scale or poor soap foot quality manufacturers.Acidizing hydrolysis method has the advantages of less investment, simple operation, favorable for the hydrolysis of oil and fat, and can recover glycerol at the same time, so it is widely used, but its hydrolysis rate can only reach 92%~95%.Hydrolysis acidification method Because the existence of impurities in the soap foot affects the hydrolysis speed of oil and the separation of oil and water, when the catalyst is used, it is easy to damage the stability of emulsion, so hydrolysis acidification method is not suitable for preparing fatty acids from soap foot.
The main processing technology for preparing fatty acid from soap foot is as follows:
(1) Saponification acidolysis
Lye sulfuric acid
↓ ↓
Soap feet - full saponification → acidolysis → water washing - crude fatty acid
In recent years, there are some new uses for cottonseed oil soapstock, such as the preparation of liquid acid (oleic acid) separated from the fatty acid of cottonseed oil soapstockPolyamide resinIt is mainly used as printing ink andadhesive。Other products include soap, film remover, plasticizer, glycerin, ink, lubricating oil and pesticide solvent, mineral processing catcher, etc.
Refined cottonseed oilSoapy footIt can be used to produce washing products, fatty acid products, and biodiesel.Shi Rubing et al. used cottonseed oil soapstock as raw material, directly methylated after acidification to synthesize mixed fatty acid methyl esters, and the conversion rate was more than 83%.The process is simple, low production cost, realizing the comprehensive utilization of resources, and eliminating the environmental pollution caused by cottonseed oil soapstock.Keskin et alDiesel engineCompared with petrochemical diesel in terms of soot emissions, power and torque, good results were obtained, indicating that biodiesel can be an ideal alternative fuel for diesel engines.[1]
