Oil refining-Alkali refining
Alkali refining is a refining method that neutralizes free fatty acids with alkali and removes some other impurities at the same time. There are many kinds of alkali used, such as lime, organic alkali, soda ash and caustic soda. The most widely used domestically is caustic soda.
1. Basic principle of alkali refining
The principle of alkali refining is the neutralization reaction between the alkali solution and the free fatty acids in the crude oil. The reaction formula is as follows: RCOOH＋NaOH→ROONa＋H2O
In addition to the neutralization reaction, there are certain physical and chemical effects.
①Caustic soda can neutralize free fatty acids in crude oil to produce sodium soap (commonly known as soapstock), which becomes insoluble gelatinous and precipitates in the oil.
②Soapstock have strong adsorption capacity. Therefore, a considerable amount of other impurities (such as proteins, mucus, pigments, etc.) are adsorbed and precipitated, and even mechanical impurities are no exception.
③ The free gossypol contained in wool cotton oil can react with caustic soda to become phenate. This phenate is more likely to be adsorbed and precipitated by soapstock in the alkali refining process, so it can reduce the color of cotton oil and improve the quality of refined cotton oil.
The soapstock produced by alkali refining contains a considerable amount of neutral oil,The main reasons is: the peptization between steel soap and neutral oil; the neutral oil is wrapped by sodium soap; the absorption of neutral oil when the soapstock aggregate into flocs.
While neutralizing free fatty acids, neutral oils may also be saponified to increase loss. Therefore, the best conditions must be selected to increase the rate of essential oils.
2. Alkali refining method
According to the equipment, there are two kinds of alkali refining methods: batch and continuous, and the former can be divided into low temperature and high temperature operation methods. For small oil plants, the batch caustic refining at low temperature is generally used.
①Batch caustic refining process
Crude oil → degumming → alkali neutralization → heating → adding water → settling → separation → oil purification → washing → drying → alkali refining → soap oil → boiling and adding salt → skimming
②Continuous caustic refining
Continuous caustic refining means that the production process is continuous. Some of the equipment can be adjusted automatically, the operation is simple, and the production efficiency is high. The main equipment used in this method is a high-speed centrifuge. Commonly used are tubular bowl and disc high-speed centrifuges.
1. Basic principle of alkali refining
The principle of alkali refining is the neutralization reaction between the alkali solution and the free fatty acids in the crude oil. The reaction formula is as follows: RCOOH＋NaOH→ROONa＋H2O
In addition to the neutralization reaction, there are certain physical and chemical effects.
①Caustic soda can neutralize free fatty acids in crude oil to produce sodium soap (commonly known as soapstock), which becomes insoluble gelatinous and precipitates in the oil.
②Soapstock have strong adsorption capacity. Therefore, a considerable amount of other impurities (such as proteins, mucus, pigments, etc.) are adsorbed and precipitated, and even mechanical impurities are no exception.
③ The free gossypol contained in wool cotton oil can react with caustic soda to become phenate. This phenate is more likely to be adsorbed and precipitated by soapstock in the alkali refining process, so it can reduce the color of cotton oil and improve the quality of refined cotton oil.
The soapstock produced by alkali refining contains a considerable amount of neutral oil,The main reasons is: the peptization between steel soap and neutral oil; the neutral oil is wrapped by sodium soap; the absorption of neutral oil when the soapstock aggregate into flocs.
While neutralizing free fatty acids, neutral oils may also be saponified to increase loss. Therefore, the best conditions must be selected to increase the rate of essential oils.
2. Alkali refining method
According to the equipment, there are two kinds of alkali refining methods: batch and continuous, and the former can be divided into low temperature and high temperature operation methods. For small oil plants, the batch caustic refining at low temperature is generally used.
①Batch caustic refining process
Crude oil → degumming → alkali neutralization → heating → adding water → settling → separation → oil purification → washing → drying → alkali refining → soap oil → boiling and adding salt → skimming
②Continuous caustic refining
Continuous caustic refining means that the production process is continuous. Some of the equipment can be adjusted automatically, the operation is simple, and the production efficiency is high. The main equipment used in this method is a high-speed centrifuge. Commonly used are tubular bowl and disc high-speed centrifuges.
Hot tags:Oil refining,Alkali refining,Alkali refining method,Batch caustic refining process,Continuous caustic refining,tubular bowl high-speed centrifuge,disc high-speed centrifuge.
