Stainless Steel Tank for Fish Oil Storage

Stainless steel is an iron-based alloy containing more than 12% chromium and is resistant to corrosion by atmospheric and liquid media, it is widely used in the fields of food, medicine and water treatment.

The core storage challenges of fish oil are: easy oxidation, sensitivity to oxygen, light, and metal ion catalysis, as well as moisture. The SS316 stainless steel bolted tank meets these requirements for light protection, airtightness, low catalysis, nitrogen filling capability, and corrosion resistance.

The requirement of stainless steel (SS316) tank for fish oil:

1.Materials of fish oil tanks must be food grade such as SS 316. 

Requirements: The inner surface must be mirror polished with a surface Ra≤0.8μm. Rough stainless steel will absorb fish oil and metal ions, which will dissolve and accelerate rancidity.

2.Structural Requirements:

● Fully enclosed design with tight-fitting, secure lids. Manholes and water intake/outlet access points shall be equipped with locks to prevent unauthorized entry.

● Overflow pipes and vent pipes shall be fitted with insect-proof screens/mesh to prevent the ingress of mosquitoes, insects, dust, and rodents.

● The tank shall be a self-supporting, independent unit and shall not utilize walls, floors, or other building structures as part of its containing surfaces.

● Dual-tank configuration shall be adopted with separate compartments for domestic (potable) water and fire-fighting water to eliminate any risk of cross-contamination.

All internal surfaces shall be smooth, free of dead corners/pockets to facilitate easy cleaning, and shall be free from cracks, leaks, and corrosion/rusting.

Stainless steel bolted tanks are made of SS316L panel and self-locked bolts, sealants , stiffener etc. They are easy to be installed on-site without any welded work.

●Hygienic & Safe The material is chemically stable and suitable for oil-based media.

1.Resistance to fish oil corrosion 

Fish oil contains free fatty acids, trace organic acids and aquatic sulfide impurities. The molybdenum element in 316L stainless steel enhances its resistance to weak acids and lipid corrosion, preventing slow corrosion by fish oil. It delivers superior corrosion tolerance compared with ordinary 304 stainless steel, carbon steel and aluminum materials.

2.No chemical reaction with fish oil occurs. 

Its inert surface avoids catalyzing lipid saponification and prevents heavy metal ion leaching. If the inner wall achieves qualified mirror polishing, the risk of peroxide formation can be greatly reduced, maintaining stable acid value and peroxide value of fish oil.

3.Compatible with all types of fish oil media.

It can store triglyceride fish oil, ethyl ester concentrated fish oil, and blended fish oil supplemented with MCT, vitamin E and rosemary antioxidants. The material will not absorb oil components nor leach plasticizers (plastic pails tend to suffer plasticizer migration during long-term storage)

●Advantages in Physical Structure and Practical Production Operation

1.Fully light-shielded with customizable structure 

Stainless steel itself is opaque. Wrapping thermal insulation and light-proof cladding on the tank exterior can completely block ultraviolet rays to prevent photo-oxidation of Omega-3.

2.Excellent airtight sealing performance 

The tank is integrally formed by welding. Manholes, feeding ports, nitrogen ports and sampling ports can all be fitted with food-grade PTFE sealing gaskets. The system supports vacuum pumping and nitrogen blanketing for inert atmosphere protection to isolate oxygen, which is a critical condition for preventing fish oil oxidation.

3.Easy to clean with no residual dead corners 

The inner wall features mirror polishing with surface roughness Ra ≤ 0.8 μm. Its smooth surface resists oil adhesion and accumulation of residual fish oil. The tank is compatible with CIP (Clean-in-Place) on-site cleaning. No grease dead zones remain after cleaning, which prevents new batches from being contaminated by long-term rancid residual oil, making it ideal for circulation in continuous production.

4.High mechanical strength, safe and durable 

It features excellent impact resistance, pressure resistance and wide temperature tolerance. A cooling water jacket can be installed to maintain constant low-temperature storage at 0~10°C. The tank can withstand vacuum and slight positive pressure nitrogen atmosphere, and is not prone to deformation or damage during transportation and storage, with a far longer service life than plastic pails.

5.Suitable for both high and low temperature working conditions 

Temperature control via jacket adapts to the whole process of fish oil refining, temporary storage and filling. It is applicable to long-term low-temperature storage as well as short-term heating blending with antioxidant additives.

●Advantages in Food & Pharmaceutical Compliance and Application

1.Compliant with food-grade and dietary supplement-grade standards 

316L stainless steel is a universally adopted material in the global edible oil and fat industry. It can pass FDA and food contact material testing, and is suitable for storing edible-grade fish oil raw materials for dietary supplements.

2.Resistant to moisture ingress and water vapor permeation 

As metal completely blocks water vapor, it will not slowly allow water penetration like plastic during long-term storage, thus preventing increased moisture inside the tank from accelerating hydrolytic rancidity of fish oil.

3.Reusable for repeated cycles with low overall cost 

Large stainless steel tanks can serve for over a decade and be cleaned and refilled repeatedly. Unlike disposable plastic pails and composite bags, they generate no consumable waste, making them suitable for mass long-term circulation in factories.

● No welding stress or heat-affected zone

Bolted connections are a cold connection process that completely avoids the problems of thermal deformation and intergranular corrosion sensitivity caused by welding, thus maintaining the inherent corrosion resistance of stainless steel.

● Superior Hygiene and Cleanability

Smooth Inner Walls: Prefabricated panels typically feature polished or embossed surfaces, resulting in a smooth, seamless finish that prevents material buildup and facilitates cleaning and sterilization.

Seamless Interior: The absence of weld seams eliminates the potential risk of bacterial growth, meeting stringent hygiene standards for the food, beverage, and pharmaceutical industries, including FDA, 3-A, and EHEDG standards.

● Wide Range of Materials and Configuration Options

Flexible Material Selection: Different grades of stainless steel (such as 304, 316L, etc.) can be selected for different parts depending on the storage medium, optimizing costs.

● Easy to maintain and repair

Replaceable panels: If a panel is accidentally damaged, only the affected section needs to be removed and replaced, making repairs quick and cost-effective.

Easy-to-replace sealing strips: Sealing is primarily ensured by high-quality food-grade elastomer sealing strips (such as EPDM). These strips can be replaced periodically as they age, keeping the tank looking brand new.

● Environmental Protection and Sustainability

100% Recyclable: Stainless steel itself is fully recyclable.

Reduce Waste: Factory prefabrication maximizes material utilization and reduces on-site processing waste.