1. Process and equipment description of alkali refining section
Unrefined crude fish oil is also called raw fish oil. Because it contains a certain amount of water, impurities, gelatin, and fish body protein, it has a higher acid value, a darker color and a strong fishy smell, so it needs to be passed through Only after refining and reaching a certain quality index can it have use value. The refining process of fish oil is similar to the refining process of vegetable oil, but depending on the raw material or product use, the refining process is quite different. The product produced by this process is mainly used as fish oil for feed.
Alkali refining and deacidification is one of the most important processes in fish oil refining. Alkali refining and deacidification is basically the same as the refining process of vegetable oil. Due to the different freshness of the raw materials from which the fish oil is extracted and the long time mixing with water during the extraction of fish oil, the acid value of crude fish oil is often relatively high, and its acid value is generally between 5mg/g and 30mg/g. For fish oils with different acid values, different deacidification processes should be selected. Alkali refining and deacidification is suitable for crude fish oils with an acid value of less than 5mg/g. For crude fish oils with an acid value of more than 5mg/g and less than 15mg/g, physical refining is adopted. It is more economical. If the crude fish oil is greater than 15mg/g and conditions permit, it is more economical to choose a process that combines physical deacidification and chemical deacidification.
Fish oil alkali refining mainly neutralizes free fatty acids, which is a typical chemical method. At the same time, alkali refining is accompanied by a physical and chemical process. The soapstock produced in the neutralization reaction can absorb some pigments, mucus and proteins, etc., and separate them from the oil together. come out.
1.Process overview
The crude oil needs to be filtered to remove insoluble impurities to less than 0.2%. The purpose is to ensure that the separation effect of the separator is not affected.
Start the crude oil pump in the pump room and pump the crude fish oil into the crude oil temporary storage tank L-01. After the high position, it will be pumped into the plate heater L-03 through the crude oil pump L-02 (controlled by the flow meter to the specified output 2.1t/h). After the oil temperature is heated to about 85°C, it is mixed with the caustic soda solution with a concentration of 12-18Be' through the multi-effect mixer L-04, and then enters the neutralization reaction L-05, and enters the centrifuge L- after the fully retained reaction. 06 separation, the soapstock separated from the heavy phase falls into the soapstock tank L-23 and then is sent to the outdoor storage tank by the soapstock pump L-22.
The light phase oil separated by the separator L-06 is kept at about 80℃ by the heater L-08, and then enters the next multi-effect mixer L-09, where it is fully mixed with hot water of about 8%-15% of the oil weight Wash with water. The washed oil is separated into waste water by centrifuge L-10, and the waste water contains a small amount of grease, which is recovered by the sludge oil-water separation tank L-31 and then pumped into the dehydration tank. After dehydration, it is pumped into the crude oil temporary storage tank L-01.
The oil after centrifugal dehydration enters the heater L-11 to be heated to about 100-110℃ and enters the vacuum continuous dryer L-12. After drying and dehydration, the alkali refining oil is cooled to 50℃ by the canned motor pump L-33 through the plate cooler L-34. Left and right to the product oil tank.
