Fish meal is a kind of feed and high-grade organic fertilizer, which is made from fish with low economic value or poor quality and waste materials in the process of aquatic products processing and production. Fish meal production is divided into wet and dry methods. At present, dry production is the main method. (1) Wet production process (1) process flow. Production process: 2. Process operation:
A. After weighing the raw material, it is fed into a shredder and cut into small pieces (small fish need not be shredded), and then into a cooker. First, it is directly fed into steam, and the stirrer is turned on and stirred continuously. After about 10 minutes, it is replaced by indirect steam, which cooks for about 15 minutes, so that the temperature in the cooker reaches 90-95 C. B. The cooked material is sent to the screw press by the screw conveyor belt, and the crushed cake solid is sent to the crude crusher for crushing. The crushed liquid still contains a lot of protein particles, which can be recovered by rolling sieve before the crushing liquid is separated and dried into finished products. The liquid part will separate the fish oil by centrifugal separation and natural sedimentation, separate the soluble protein solution from fish oil, and then vacuum concentrate and spray dry to form high quality fish meal. C. Fish meal cakes still contain a lot of water. For easy drying, the cake should be crushed roughly and then dried in a dryer for about 30 minutes, so that its moisture content is less than 10%. Then it is sent to a magnetic crusher to absorb the iron and other impurities in fish meal. After sieving, it is the finished fish meal. After cooling, it can be stored in bags or discharged from the factory. (3) Main equipment: a. Gear hobbing crusher B. Cooker, sandwich, pressure withstanding, with agitator. C. Primary grinder and magnetic grinder. D: Rolling screen with hole less than 30 mm. (2) Dry process.
Technological process: 2. Technological operation: a. Cut large pieces of raw materials into a steam dryer, steam cooking and drying, time is about 4 hours, temperature is 100-105 C. In the process of steaming and drying, the agitator on the central shaft of the steaming and drying machine keeps stirring to prevent dry coke. Steaming and drying degree should be mastered according to the actual operation, and the general moisture content should be mastered at about 10%. If it is used as non-skimmed fish meal, it can be packaged after steaming and drying, and passed the inspection. If it is used as skimmed fish meal, it should be degreased according to the process. B. Degreasing of fish meal includes squeezing method and solvent extraction method, which are commonly used in China. The method is to first pick out a large amount of impurities, while hot fish meal into the press, the grease will be squeezed out. Generally, the oil content of fish meal is about 12% by using screw press. It is difficult to reduce the oil content further. The extraction process is complex and requires high technology. The oil content of fish meal can be reduced to less than 2%.
(3) Main equipment: a. Steam dryer: horizontal, double jacket, central shaft equipped with agitator. B. Press: spiral type. C. Quality standard of fish meal (refer to SC118-83)