Fish Oil and Fish Meal

Separators and decanters have been used for the recovery of fish meal and fish oil for over 50 years. Over the years, the processes used have been adapted to the demands on the product and raw materials.

 

The fish processes used have also heavily impacted the further development of decanters and separators. Besides a few special applications, the so-called conventional process, the “whole fish” process and the 3-phase process are primarily used. The 3-phase process is gaining in attraction due to the growing demand for small-scale fish meal installations.

 

The most important task in obtaining fish meal and fish oil is to separate the three main components of the raw material – solid (protein), fat and water – efficiently and effectively in a relatively short contact time. The thermal treatment to coagulate the raw material is therefore of the highest importance and determines quality and fat content. Heating coagulates the protein, and the fat-containing cells are gently disintegrated to release the oil. This thermal treatment is now obligatory in all processes used.

 

In the conventional process, the cooked raw material is fed to a screw press before a 2-phase decanter clarifies the press water and separates the solids in the process.

 

An alternative is also to use the so-called whole fish process, in which the 2-phase decanter replaces the screw press. Using the “whole fish“ decanter results in a series of benefits when processing particular fish species as compared to the conventional process. These include simplified process control, higher productivity and better meal quality in respect of fat and protein content. In both processes, self-cleaning separators are then used to remove oil from the press water in the first stage and polish the oil in the second stage.

 

A specific alternative to these standard methods is to recover fish meal and fish oil using 3-phase decanters. These methods are characterized by an exceptionally small space requirement and offer an economic solution for small processing capacities in particular.

 

Besides the classic variant which separates the solids using a press in analogy to the conventional process, it is possible to use a combination of whole-fish and 3-phase decanters for very small processing quantities. As a press can be dispensed with here, the process again becomes even simpler.

 

With the fish processing industry in a period of change, the future belongs to these processes in particular. Climate change and variable fishing quotas in certain regions of the world are the reasons why there are fewer and fewer large-scale plants capable of processing capacities of 100 to 200 tons per hour. On the other hand, there is a growing number of businesses producing much smaller outputs but making high profits in the process.

 

GEA Westfalia Separator‘s 3-phase decanter is a fitting response to this change. The raw materials are first carefully minced and heated. Following coagulation, the 3-phase decanter goes into action. It separates the suspension cleanly into the three phases of solids, water and oil. As the oil phase may still contain small residues of free water and solids, a polishing separator is recommended downstream to remove reliably even these tiny impurities. The result is purest fish oil.