Application of powder activated carbon in oil production

The application of powdered activated carbon (PAC) in the decolorization and purification of edible oil is an important part of the modern oil processing process. Its main purpose is to remove pigments, impurities and other bad odors in edible oil through physical adsorption and chemical adsorption, and improve the quality and stability of oil products. The following is a detailed introduction to

 

The application of powdered activated carbon (PAC) in the decolorization and purification of edible oil is an important part of the modern oil processing process. Its main purpose is to remove pigments, impurities and other bad odors in edible oil through physical adsorption and chemical adsorption, and improve the quality and stability of oil products. The following is a detailed introduction to the use of powdered activated carbon for edible oil decolorization and purification.

Basic Overview of Powdered Activated Carbon

Powdered activated carbon is a carbon material with high adsorption capacity made from natural materials (such as wood, coal, coconut shell, etc.) after carbonization and activation. It has a large specific surface area, a well-developed pore structure, and excellent physical and chemical adsorption capacity. The adsorption capacity of activated carbon mainly depends on its pore structure and surface area, and micropores (pore size less than 2nm) and mesopores (pore size 2-50nm) are its main adsorption sites.

Characteristics of Powdered Activated Carbon

Large specific surface area: The specific surface area of ​​powdered activated carbon is usually 500-1500 m²/g, providing a large number of adsorption sites.

Strong adsorption capacity: It can effectively adsorb pigments, free fatty acids, peroxides and other impurities in oils and fats.

Wide adaptability: It has good decolorization effect on different types of edible oils (such as vegetable oils and animal oils).

Easy to use: The powdered form makes it easy to disperse and mix during the oil processing process, improving the decolorization efficiency.

Principle of action of powdered activated carbon in edible oil decolorization

Adsorption principle

The decolorization effect of powdered activated carbon mainly depends on its adsorption performance. The adsorption process can be divided into physical adsorption and chemical adsorption:

Physical adsorption: Based on the van der Waals force, the microporous structure on the surface of activated carbon can capture and adsorb pigment molecules and other small molecular impurities in oils and fats. Due to the large specific surface area of ​​activated carbon, a large number of adsorption sites are provided, which can effectively remove pigments and impurities in oils and fats.

Chemical adsorption: Through chemical bonding, activated carbon reacts chemically with certain chemicals in oils and fats (such as free fatty acids and oxidation products), thereby removing these undesirable components.

Pore structure

The pore structure of powdered activated carbon plays a vital role in its adsorption performance. The pores of activated carbon can be divided into micropores, mesopores and macropores. Micropores have a high adsorption capacity for small molecular impurities, while mesopores and macropores help to adsorb larger molecules and accelerate the adsorption process. The synergistic effect of different pore sizes enables activated carbon to efficiently remove various types of pigments and impurities during the decolorization process.

Process flow of edible oil decolorization and purification

Pretreatment

Before decolorization, edible oil usually needs to be pretreated to remove larger suspended matter and colloidal impurities. Pretreatment methods include filtration, precipitation and centrifugation. The purpose of this step is to reduce the consumption of activated carbon in the subsequent decolorization process and improve the decolorization efficiency.

Add powdered activated carbon

Prepare the mixture: Heat the pretreated edible oil to an appropriate temperature (generally 80-100℃), and then add powdered activated carbon in a certain proportion. Usually, the amount of activated carbon added is 0.5%-2% of the weight of the oil.

Stir evenly: In order to ensure that the activated carbon is fully in contact with the oil, the mixture needs to be stirred, and the stirring time is generally 20-30 minutes. The purpose of this step is to evenly distribute the activated carbon in the oil and improve the decolorization efficiency.

Decolorization process

Adsorption decolorization: During the stirring process, activated carbon removes pigments and impurities from oils and fats through physical and chemical adsorption. The efficiency of the adsorption process is affected by factors such as temperature, time and amount of activated carbon.

Standing and filtering: After the stirring is completed, it needs to stand for a period of time (generally 10-20 minutes) to allow the activated carbon to fully adsorb impurities. Then the activated carbon is separated from the oil by filtering or centrifugal separation.

Post-treatment

Edible oil after decolorization usually needs post-treatment to ensure the quality and stability of the oil. Post-treatment steps include deodorization, deacidification and refining. The purpose of these steps is to remove residual trace impurities and bad odors, and further improve the quality of the oil.

Factors affecting the decolorization process of powdered activated carbon

Temperature

Temperature has a significant effect on the decolorization process. Generally speaking, higher temperatures help the adsorption capacity of activated carbon, but too high temperatures may cause oil oxidation and affect the quality of the oil. Therefore, it is necessary to select a suitable temperature range (usually 80-100℃) during the decolorization process to balance the decolorization efficiency and oil stability.

The length of the decolorization time directly affects the adsorption effect of activated carbon. Generally, a stirring time of 20-30 minutes can achieve a good decolorization effect. Too short a time may lead to incomplete adsorption, while too long a time may increase energy consumption and operating costs.

Activated carbon dosage

The amount of activated carbon has a decisive influence on the decolorization effect. Too little dosage will result in poor decolorization effect; too much dosage can improve the decolorization effect, but it will increase costs and may affect the quality of the oil. Therefore, it is necessary to select the appropriate amount of activated carbon according to the specific situation, generally 0.5%-2% of the oil weight.

Oil properties

Different types of oils have different properties, which also affect the adsorption effect of activated carbon. For example, the pigments and impurities in vegetable oils and animal oils are different, and the decolorization process parameters need to be adjusted according to the specific situation.

Advantages and disadvantages of powdered activated carbon decolorization

Advantages

Good decolorization effect: Powdered activated carbon has a high adsorption capacity and can effectively remove pigments and impurities in oils.

Strong adaptability: It has a good decolorization effect on various types of edible oils.

Easy operation: The decolorization process using powdered activated carbon is simple, easy to control and operate.

Disadvantages

High cost: The price of activated carbon is relatively high, which increases the cost of oil processing.

Waste treatment: The waste activated carbon after decolorization needs to be properly handled to avoid environmental pollution.

May affect the quality of oil products: If the operation is improper, the residual activated carbon particles may affect the taste and quality of the oil products.

Conclusion

The application of powdered activated carbon in the decolorization and purification of edible oil is an important part of modern oil processing technology. Its excellent adsorption performance and wide adaptability make it an effective means to improve the quality of oil products. By reasonably selecting and optimizing the decolorization process parameters, the decolorization efficiency can be improved and the production cost can be reduced while ensuring the quality of the oil products. At the same time, in practical applications, attention should also be paid to the treatment of waste activated carbon to ensure environmental friendliness and sustainable development.