Chemical refining process

There is usually less concern about the red color at this stage because removal of phosphorus, trace metals, and soap are of prime importance and the red color is reduced later in the deodorizer. The oil is deodorized under the same conditions as in physical refining except that in the fatter the deodorizer is designed to handie a much larger volume of fatty acids and therefore has a few extra design features compared to the chemical refining process. The typical analysis for deodorized sunflower oil is shown below  

Calcium Magnesium Chlorophyll Lovibond Red color Cold test, h at 0°C 

An increase in free fatty acid content is due to die hydrolysis of die soap in the water-washed oil by the acid activated bleaching clay. This number can be higher if die soap in die water-washed oil is higher. 

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Biotechnology can potentially provide solutions to some of these problems. Bioprocesses are, in general, environmentally better than chemical refining processes. 

Figure 4.4 shows the different stages in seed preparation and a classical chemical refining process. The general methods employed to produce edible oils suitable for human consumption consist of (a) seed preparation, (b) extraction, (c) degumming, (d) neutralization, (e) bleaching, (f) deodorization, (g) hydrogenation, and sometimes winterization. 

Figure 5. Diagrams for the existing chemical refining process and the proposed membrane degumming process (32).

This process alone, in addition to the advantages summarized above, shows the following benefits of the physical refining that will also be obtained. The various costs such as installation (22%), capital investment (20%), steam usage (28%), cooling water (7%), process makeup water (85%), wastewater treatment (63%) electrical power (62%), and refining loss (60%) are lower compared with that of the chemical refining process. 

There are two principal continuous refining processes physical refining and chemical refining. Three other continuous refining techniques used in the sunflower oil industry are improved modifications of the above processes. These include the cold chemical refining process, the modified chemical refining process and the modified physical refining process. 

This process is very similar in principle to the standard chemical refining process except ... 

The cold oil is treated with caustic in the same manner as in the standard Long-Mix chemical refining process. 

The oil is then heated to 80-90°C for water washing as in the Long-Mix chemical refining process and centrifuged to remove excess soap and water. 

A total of 10,747 active, qualified ISHN direct request subscribers were selected from these industries -50% manufacturing, 20% construction, 10% utilities, 10% chemical/refining processes, 10% consultants. A web-based survey was used, with fielding dates September 9-17, 2010. 363 usable completed surveys were returned, for a 3% response rate. 

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