At present, the counterflow cooler is commonly used in the cooling process, and the main parameters are cooling air volume and cooling time. During the cooling process, the phenomenon of uneven grain cooling caused by uneven cooling of the particles, excessive cooling air volume and excessive cooling time should be avoided, so that the surface cracks of the particles are more and easily broken. The height of the material in the cooler should be kept as flat as possible in the direction of the surrounding, otherwise it will cause a wind phenomenon and cause uneven cooling. The cooling air volume should be controlled within the range of 22.6~31.3 m3/(min·t) (Zhang Wenliang et al., 2004) according to different particle size, and the cooling time is controlled at 6~9 min. Excessive air volume and short cooling time are also likely to cause inconsistencies in the outer surface and internal moisture of the particles, which may cause the feed to rupture and mold.
For some aquatic products, in order to further improve the PDI and improve the stability of the water, the heat preservation and curing process is often added before cooling, and then cooled or dried. Practice has proved that this is a feasible and effective method, which can significantly improve the PDI and water stability of pellet feed.
Portable spectrophotometer,45/0 spectrophotometer,Hardware spectrophotometer
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