Edible Oil Refining System Offer a Customized Solution be Panic Buying

Specifications

Edible oil physical refining system offer a customized solution be panic buying

Vegetable oil is one of the most important primary foods. The quality of the final product depends on the refining method and the nature of the crude oil. JinXin offers a wide range of solutions designed to maximize value, ranging from a separator with a daily capacity of 10 tonnes for operators of small oil mills to separators with capacities of more than 1600 tonnes per day for large refineries.

The production processes and technologies used must be as varied as the different types of oil processed.

JinXin designs and manufactures a customized solution which is tailored to meet the requirements of the specific application. The centrifuge is always found at the heart of the installation. Whether a self-cleaning separator with a maximum level of automation or a discontinuously operating system, every customer is able to find the best solution in economic and technological terms for thier specific production tasks. We not only supply the mechanical separation facility, but also supply all other components and systems necessary for an efficient and reliable production line.

Different Processes – One Solution

Chemical Refining

Two processes have been developed for refining edible oils and fats. The decision as to which process is to be used depends on the type and quality of crude oil to be processed.

Chemical refining is the traditional method, where the free fatty acids of the crude oils are neutralized with caustic soda. The resultant sodium soaps are separated by means of separators. The neutral oils are subsequently bleached and deodorized. This method can be used for reliably refining virtually all crude oils, including oils of low quality, with the exception of castor oil.

Physical Refining

In the alternative method of physical refining,­ the free fatty acids are removed by distillation in one stage during deodorizing­. A fundamental criterion for using this method is that the crude oils should be degummed as effectively as possible. This is only possible to a limited extent with some crude oil types. Other oils, for instance cottonseed oil or fish oil, are fundamentally not suitable for physical refining.

Clarification of Press Oil

The oil which is discharged from expeller presses has various solid content levels depending on the oil seed type and the condition of the press. In order to remove particularly large solid particles, the oil is usually fed into a settling tank, which is used simultaneously as a buffer tank. In some installations, a vibrating screen is used for pre-cleaning. In others, the oil is taken directly from the press to the press oil clarification unit.

In order to support the separation process, the solids are wetted with hot water. A water quantity of 1% in relation to the oil quantity is normally adequate. The water is mixed with the oil in the decanter. The decanter – which is a horizontal scroll-type centrifuge – continuously separates the solids from the oil.

As a side effect of adding water, any phosphatides present are hydrated and then removed together with the solids.

In order to avoid oil losses, the solids are returned to the press. The purified oil is either processed directly or, if it is stored or sold, it should be dried in a vacuum.

Water Degumming

A smooth action pump is used for conveying the crude oil to a heat exchanger, which is used for heating the crude oil to the optimum process temperature. A quantity of hot water corresponding to the content of phosphatides in the crude oil is added to the oil and mixed intensively. A special centrifugal mixer, which simultaneously conveys the oil directly to the separator, is used for this purpose. The hydratable phosphatides swell immediately due to the particularly intensive mixing of oil and water, and no additional reaction time is necessary.

A separator is used to continuously separate the phosphatides which are insoluble in oil. They are either added directly to animal is a valuable by-product, which is used as an emulsifier, e.g., in the food, animal feed, pharmaceutical and cosmetics industries.

The degummed oil is either conveyed directly to the refining stage, or it has to be dried in a vacuum if it is stored or sold.

Simple Acid Degumming

Simple acid degumming is suitable for pretreating palm oil, palm kernel oil, coconut and olive oil as well as animal fats. This method of degumming aims to reduce bleaching earth consumption in the physical refining process, making this an extremely economical method.

The crude oil is initially heated to the optimum process temperature in a heat exchanger. A metering unit is used for adding a small quantity of phosphoric or citric acid, which is mixed intensively with the oil in a centrifugal mixer. After a brief reaction time, hot water is added and mixed.

The heavy phase which contains phosphatides, proteins, pigments and other impurities is then separated. The oil which is treated in this way is generally sent directly to the bleaching stage and deacidified by means of distillation.

Super-/Uni-Degumming

After the crude oil has been heated, specially modified phosphatides which subsequently facilitate phosphatide hydration can be added. However, this is only necessary in exceptional cases. Under normal conditions, a small quantity of citric acid is added to the crude oil and mixed very intensively with the oil. After a certain reaction time, the oil is cooled and the necessary quantity of water is added for hydrating the phosphatides. After more reaction time in an agitator tank, the oil is heated to separating temperature and the gums are separated from the oil in a separator.

This concludes the super-degumming stage. However, depending on how the oil is to be subsequently treated, it may be necessary to remove the phosphatides more efficiently, as extremely fine particles cannot be separated. A further process stage, the uni-degumming method, has been developed for this purpose.

The oil is cooled for a second time and a small amount of caustic soda is added. Mixing of the caustic with the oil in a special mixing tank is followed by further reaction time in an agitator tank, during which the fine phosphatide particles agglomerate to form larger particles. These can be separated in a clarifier after the oil has been heated. The oil is subsequently dried in a vacuum.

The hydration and agglomeration of phosphatides at low temperature produces a positive side effect for wax-containing oils (e. g., sunflower oil and corn oil). Some of the wax crystallizes and is separated together with the gums. This produces a considerable advantage in the subsequent refining process of these oils.

TOP-Degumming

The crude oil is initially heated to the optimum process temperature and a small quantity of acid is added. Following intensive mixing and a brief reaction time, some of the acid is neutralized with diluted caustic soda. After mixing in a centrifugal mixer, the gums are separated from the oil in a separator.

Because very fine phosphatide particles cannot be separated, a certain amount of water is again added to the oil. Following a brief reaction time, the mixture is conveyed to a high-performance clarifier which is able to generate an extremely high g-force. This enables the fine particles to be continuously separated with the water. In order to avoid oil losses, this phase is recycled into the feed of the first centrifuge, where the fine gum particles are separated together with most of the phosphatides. The oil which is degummed in this way is subsequently dried.

Standard Neutralization

This method is suitable for neutralizing pre-degummed edible oils or oils which originally only have a low phosphatide content. The free fatty acids are saponified with caustic soda, and the sodium soap is separated.

The oil is initially heated to the optimum process temperature. In order to condition the non-hydratable phosphatides, a small quantity of concentrated phosphoric acid is added and intensively mixed with the oil. Following a brief reaction time, diluted caustic soda is added in order to neutralize the free fatty acid and the phosphoric acid. After mixing with the oil, the mixture is either conveyed directly to the first separator or it passes through a further reaction tank. The latter is recommended only for oils with a relatively high phosphatide content. Self-cleaning separators are mostly used for separating the sodium soap. However, the residual soap content in the neutral oil is still too high for the subsequent process stages and it must be further reduced by one or two washings. For this purpose, hot water is added to the oil and intensively mixed. The soapy wash water is removed in a further separator.

In general, one wash stage is adequate. A second washing is only necessary if very low residual soap contents are required. However, a low residual soap content can also be achieved by acidifying the wash water with citric or phosphoric acid.

A second caustic treatment of the neutral oils is only advisable in exceptional cases. This mainly applies to cottonseed oil, so most of the gossypol is removed. This oil should always be neutralized in 3-stage installations.

Depending on the subsequent bleaching method, the neutralized and washed oil is subsequently vacuum-dried.

Neutralization of Undegummed Oils

This method has become established mainly in the USA for refining soybean oil. The process is a combination of degumming and neutralization.

For conditioning the non-hydratable phosphatides, a small quantity of phosphoric or citric acid is added to the crude undegummed oil. In some cases, the acid is added in the feed tank with an agitator upstream of the installation. This involves several hours of reaction time. However, a more effective method is to add the acid upstream of a centrifugal mixer. The intensive mixing enables the reaction time to be reduced to a few minutes. Diluted caustic soda is then added in order to neutralize the free fatty acids. Adequate water must be present with the caustic in order to hydrate the phosphatides. Following a reaction time of several minutes in special retention mixers, the oil is heated and added directly to the first separator in order to separate the soapstock.

The neutral oil is washed in order to further reduce the residual soap content. For this purpose, a certain quantity of hot water is added to the oil, mixed in a centrifuge and separated into wash water and oil in a separator. The residual humidity of the oil is further reduced in a vacuum drier.

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