1. Overview
Fish meal is a high-protein feed that uses one or more kinds of fish as raw materials and is processed by degreasing, dehydration, and crushing. The world's fishmeal producing countries mainly include Peru, Chile, Japan, Denmark, the United States, the former Soviet Union, Norway, etc. The export volume of Peru and Chile accounts for about 70% of the total trade volume. The production of fishmeal in China is not high. The main production areas are Shandong Province and Zhejiang Province, followed by Hebei, Tianjin, Fujian, Guangxi and other provinces and cities. At the end of the 20th century,our country imported about 700,000 tons of fishmeal every year, about 80% of which came from Peru, and less than 10% of its imports from Chile. In addition, there were also a small amount of imports from the United States, Japan and Southeast Asian countries. Although Chinese feed workers have been researching and exploring low-fishmeal diets and fishmeal-free diets, fishmeal is still an important animal protein-added feed and cannot be replaced by other feeds.

Fish oil is a collective term for all oils in the fish body. It includes body oil, liver oil and brain oil. The main fish oil is a kind of oil extracted from fatty fish, rich in omega-3 polyunsaturated fatty acids (DHA and EPA) ), has health benefits such as anti-inflammatory and regulating blood lipids. In a broad sense, fish oil refers to not only fish oil preparations in the form of capsules, but also fat in fish bodies. The main functional component is ω-3 polyunsaturated fatty acids.

2．Processing technology of full wet fish meal and fish oil
Combined with the customer's investment scale, plant site selection, environmental protection requirements and other specific conditions, we can provide 4 sets of different process schemes to treat protein water, and choose the corresponding supporting equipment.Here is a brief introduction to the 4 sets of process schemes

Option 1: Direct discharge process of protein water
This scheme is suitable for local fish meal companies with low environmental protection requirements, and adopts a production process that directly discharges the fish protein water from the separator. In the continuous production process, the protein water from the separator is concentrated in the pool, and is directly discharged outside the factory using a water pump or open ditch. It has the characteristics of low investment and simple operation; but the protein water is rich in soluble protein, vitamins, and inorganic Various nutrients such as salt and fat are the elements needed to promote animal growth and are easy to digest and absorb. If this protein water is discharged directly, it will not only cause pollution to the surrounding environment, but also a great waste of limited resources, and at the same time, consider the place where the protein water is discharged. With this program, the yield of fish meal is 5:1, that is, about 1 kg of finished fish meal can be obtained for every 5 kg of raw fish.

Option 2:  All protein water recovered to the dryer
This scheme is suitable for any place, especially suitable for mountainous areas or inland areas where water resources are lacking. The fish protein water from the separator is fully recycled to the dryer and dried into a fish meal production process. In the continuous production process, the protein water from the separator is concentrated in the pool, connected by pipes, and the metering pump is used to continuously and uniformly send the protein water into the dryer, fully mix with the squeezed cake, and dry together to become fish meal . With this scheme, the addition of protein water will inevitably affect the actual processing capacity of the dryer. To ensure the continuous operation of the entire production line and the processing capacity of raw fish, a large-capacity dryer or multiple dryers are required. machine. At the same time, the boiler's evaporation capacity must be increased accordingly to ensure that sufficient steam is provided. With this method of processing, the protein content of the finished fish meal can be increased by 1 to 2%, and the yield of fish meal is 4:1, that is, about 1 kg of finished fish meal can be obtained for every 4 kg of raw fish.

Option 3: The concentrated protein water is recycled to the dryer 
This program is suitable for places near the sea or near the river to obtain a large amount of circulating cooling water required for the use of concentration equipment. The fish protein water from the separator is concentrated by a double-effect exhaust gas falling film concentration device, and then it will produce The concentrated liquid with a concentration of about 30% is recycled to the dryer and dried into the production process of fish meal.

In the continuous production process, the protein water from the separator is heated to 80°C by the protein water heating tank, and then enters the double-effect waste steam falling film concentration device for system circulation. It is concentrated under vacuum and part of the water is evaporated. After reaching the 30% concentration required for production, it will pass through the pipeline and use the metering pump to continuously and uniformly send the obtained concentrated liquid into the dryer, fully mix with the pressed cake, and be dried together to become fish meal. Due to the addition of concentrated liquid, the drying work of the dryer has increased. In order to ensure the assembly line operation of the entire production line and ensure the processing capacity of raw fish, the drying capacity of the dryer must be increased. Compared with the second plan, the steam consumption of this plan is reduced, because the double-effect waste steam concentration device uses the waste gas from the equipment as the heat source to evaporate part of the water in the protein water, which not only turns waste into treasure, but also reduces The production cost of fish meal. With this program, the protein content of the finished fish meal can be increased by 1 to 2%, and the yield of fish meal is 4:1, that is, about 1 kg of finished fish meal can be obtained for every 4 kg of raw fish.

Option 4: concentration of protein water to produce fish soluble
The scheme is also suitable for the place near the sea or the river. The fish protein water from the separator is concentrated to 30% concentration through the double-effect exhaust falling film concentration device, and then concentrated to 50% concentration again through the steam vacuum concentration device, and it becomes the production process of concentrated fish soluble products.

In the continuous production process, the protein water from the separator is raised to 80℃ by the protein water heating tank and then enters into the double-effect waste steam falling film concentrator for systematic circulation. As the material boils and evaporates under vacuum decompression, the steam and liquid generated is separated from the material. When the solid content of the protein water reaches about 30%, the concentrated solution is driven into the steam vacuum concentrator to boil and evaporate again until the solid content of the material reaches more than 50%, then it becomes the fish soluble product. The product contains rich vitamins, trace elements and unknown growth factors, especially the protein is water-soluble protein, easy to be digested and absorbed by aquatic animals, so it is an ideal raw material for aquatic feed. At the same time, the product has a strong fishy smell, can be used as a new attractant, adhesives, and can improve the palatability of aquatic feed, promote the rapid growth of animals, so as to greatly improve the use efficiency of feed. Using this method, the yield of fish meal is 5:1, that is, about 1 kg of finished fish meal can be obtained for every 5 kg of raw fish. The yield of fish soluble was 16:1, that is, for every 16 kg of raw fish, about 1 kg of finished fish soluble with a concentration of 50% could be obtained.