Soybean Oil Deacidification: Alkali Refining Deacidification Process and Equipment

Basic principles of alkali refining deacidification

In the production process of soybean oil, deacidification is one of the key steps to ensure the quality of the oil. Alkali refining deacidification is the main deacidification method. Its basic principle is to use alkaline substances, usually lye, to react with free fatty acids in oil and fat to form saponification products, thereby removing free fatty acids from oil and fat.

Selection of alkaline substances

Lye: Usually sodium hydroxide (NaOH) or potassium hydroxide (KOH) is used as the alkaline substance. The type and concentration of lye should be selected according to the specific production requirements and the properties of the oil.

Deacidification reaction process:
Free fatty acids react with lye to form saponification products (soap) and glycerin. The chemical equation for this reaction is:
Fatty acid + lye → saponification + glycerin
Among them, fatty acids are free fatty acids in oils, and lye is an added alkaline substance.

• separation and removal

The generated saponified products form colloidal particles in the water, and these particles can be effectively separated from the oil through precipitation and separation steps. This step usually involves the use of sedimentation tanks and separation equipment.

• Control parameters

Temperature: Control the reaction temperature, usually between 50 degrees Celsius and 80 degrees Celsius, to increase the reaction rate.

Stirring: Stirring ensures complete mixing of the reaction and promotes the reaction.

Alkali to oil ratio: Control the appropriate alkali to oil ratio to ensure that the alkali solution fully reacts with free fatty acids.

The basic principle of alkali refining deacidification is to convert free fatty acids into separable saponified products through chemical reactions, thereby achieving effective removal of free fatty acids. In actual operation, the reaction conditions need to be reasonably adjusted according to the specific oil composition and production requirements to achieve the best deacidification effect. .

Three factors affecting alkali refining deacidification

The effect of alkali refining deacidification is affected by many factors, including crude oil quality, alkali concentration, temperature, reaction time, etc. This section will detail the impact of these factors on the deacidification effect and how to optimize these factors to improve the efficiency of alkaline refining deacidification.

• 1. Crude oil quality (reduce the content of free fatty acids)

The acid value and impurity content in crude oil directly affect the deacidification effect of alkali refining. Crude oil with high acid value and large amounts of impurities will reduce deacidification efficiency. In order to optimize the effect, the crude oil can be pretreated in advance, such as acidification or precipitation, to reduce the acid value and impurity content.

• 2. Alkaline concentration control

The choice of alkali concentration directly affects the rate and effect of the deacidification reaction. Appropriately increasing the alkali concentration can accelerate the deacidification reaction, but too high a concentration may lead to excessive saponification and increased costs. It needs to be adjusted according to the specific situation and small-scale experiments are conducted to find the optimal concentration.

• 3. Reasonable temperature range

Temperature has a significant impact on the alkali refining deacidification reaction rate and neutralization effect. Appropriate temperature helps to increase the reaction rate, but too high temperature may lead to loss of oil quality. Therefore, in actual operation, it is necessary to accurately control the temperature of the alkali refining reaction to balance the requirements of reaction rate and grease quality. It needs to be controlled within a suitable temperature range, usually between 50 degrees Celsius and 80 degrees Celsius.

• 4. Neutralization reaction time

Reaction time refers to the time it takes for the alkali solution to react with the acidic substances in the crude oil. Longer reaction times help neutralize acids more completely, but also increase production cycle time and energy consumption. When choosing reaction time, economic costs and product quality need to be considered comprehensively.

Optimizing these factors can improve the efficiency of alkali refining deacidification, ensure the thorough progress of the deacidification reaction, and obtain high-quality oil products. In actual production, it is recommended to conduct small-scale tests according to specific conditions, and make adjustments and optimizations based on the test results.

Alkali refining deacidification process

Soybean Oil Neutration Processing Flowchart

• 1. Solvent selection

Selecting appropriate alkaline substances is an important part of the alkali refining deacidification process. Commonly used alkaline substances include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)₂), etc. Selecting the appropriate solvent requires consideration of the following factors:

Properties of alkaline substances: Different alkaline substances have slightly different neutralizing effects on grease, and they need to be selected according to product requirements.

Cost: The price and availability of solvents are important factors influencing choice.

Treatment of neutralization products: Salts generated from different alkaline substances have different properties, which may have an impact on subsequent processing steps and require appropriate consideration.

• 2. Control of reaction conditions

Controlling reaction conditions is crucial to the alkali refining deacidification process. From temperature to pressure, we'll delve into how to achieve the best reaction under different conditions and explain the impact on oil quality.

Temperature: Temperature directly affects the reaction rate and neutralization effect. Appropriate temperature can increase the reaction rate, but it is necessary to avoid excessive temperature leading to grease loss.

Pressure: Pressure has relatively little effect on alkali refining deacidification and is usually carried out at atmospheric pressure.

Reaction time: A reasonable reaction time needs to be determined according to the specific process and product requirements. Too long may increase the production cycle, and too short may lead to incomplete neutralization.

• 3. Optimization of operating procedures and monitoring methods

Detailed introduction to the operation steps of alkali refining and deacidification, including stirring speed, dosing method of alkali solution, etc. At the same time, the importance of real-time monitoring methods is discussed to ensure timely adjustment of process parameters during the production process and to ensure product quality.

Temperature: Temperature directly affects the reaction rate and neutralization effect. Appropriate temperature can increase the reaction rate, but it is necessary to avoid excessive temperature leading to grease loss.

Pressure: Pressure has relatively little effect on alkali refining deacidification and is usually carried out at atmospheric pressure.

Reaction time: A reasonable reaction time needs to be determined according to the specific process and product requirements. Too long may increase the production cycle, and too short may lead to incomplete neutralization.

Selected alkali refining deacidification equipment

• 1. Alkali refining reactor

The alkali refining reactor is the core equipment in the alkali refining deacidification process. Its structure and working principle play a key role in the entire production process.

Structure: The reactor usually consists of a stirring system, a temperature control system and a dosing system. The stirring system ensures that the grease and alkali solution are fully mixed, the temperature control system maintains the reaction temperature, and the dosing system is used to control the dosing speed of the alkali solution.

Working principle: Neutralization reaction occurs between soybean oil and alkali liquid in the reactor, and the acidic substances are neutralized into salts and form precipitation. Stirring ensures that the reaction proceeds evenly, the temperature control system maintains an appropriate reaction temperature, and the dosing system achieves accurate dosing of alkali solution.

Notes: In practical applications, attention needs to be paid to selecting corrosion-resistant materials to cope with acidic substances, ensuring the uniformity of the mixing system, and timely maintenance and cleaning of equipment to prevent the accumulation of sediments.

• 2. Separation equipment - centrifuge

After the deacidification process, effective separation of grease and alkali is required. Grease and alkali are separated by centrifugal force. Its advantages include good separation effect, large processing capacity, and easy operation.

• 3.Automated control system

In modern soybean oil production, automated control systems play a key role. It has real-time monitoring and control functions of temperature, pressure, stirring speed and other parameters, which can accurately adjust the conditions of alkali refining reaction and improve production efficiency.

Through an in-depth discussion of the soybean oil alkali refining deacidification process and equipment, we can better understand how to optimize the production process and improve product quality. In an increasingly competitive market, mastering advanced technology and equipment will become the key to staying competitive. Alkaline refining and deacidification is a key step in soybean oil production, and its optimization will directly affect the market competitiveness of the final product.