Protein Recovery: Fishmeal & Fish Oil Processing

After fish cooking and screw pressing, the expelled liquid comprises water, oil, and fine suspended tissues. Once centrifuges separate the crude oil, the remaining liquor is known as stickwater. It contains 6% to 9% dry solids rich in valuable soluble proteins, free amino acids, and minerals. Without multi-effect SonFlow evaporation, a facility sacrifices 15-20% of total meal output while facing massive wastewater treatment penalties.

Raw pressed fish liquor contains fine bone fragments, scales, and sticky lipids. Standard narrow-gap plate heat exchangers trap these fibers at metal contact points, creating thick insulating crusts within hours. SonFlow Free Flow features wide open flow channels and smooth plate corrugation with zero contact points in the flow direction, permitting tissue-laden fluids to pass freely and enabling rapid periodic CIP flushing.

Marine fish oil is exceptionally rich in polyunsaturated omega-3 fatty acids like EPA and DHA, which degrade rapidly under heat and atmospheric oxygen. Upon exiting disc-stack polishing centrifuges at 90°C, the oil routes immediately through hermetic SonFlow plate coolers that drop temperature swiftly to 30°C, followed by transfer into stainless steel tanks protected under inert nitrogen blanketing.

High chloride ion concentrations in sea-caught fish combined with 70°C - 95°C operating temperatures generate severe pitting and crevice corrosion. DanPumps engineers casings and impellers cast from Duplex (2205) or Super Duplex stainless steel, coupled with Silicon Carbide or Tungsten Carbide mechanical seal faces flushed with pressurized barrier fluid.