Stainless Steel Coil Tube for Floating Roof Oil Tank Heating Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered heat transfer element specifically designed for immersion heating systems in floating roof oil storage tanks. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product is engineered to facilitate efficient thermal energy transfer to petroleum products, ensuring proper viscosity management and flow characteristics within large-volume storage facilities. The coil tube design maximizes the surface-area-to-volume ratio, enabling superior heat exchange performance under demanding industrial conditions.
This product represents a critical component in the thermal management infrastructure of the petroleum and petrochemical industries, where maintaining optimal fluid temperature is essential for operational safety, product quality, and process efficiency. The numerical simulation studies conducted on the heating process of floating roof oil tank coil tubes have validated the thermal performance characteristics and structural integrity of this design under various operating scenarios.
Material & Properties
Material Grades
- Austenitic Stainless Steel — Primary grades include SUS304 (UNS S30408), SUS316 (UNS S31608), and SUS321 (UNS S32108)
- Superior Corrosion Resistance — Chromium content ranging from 18% to 26% provides excellent resistance against sulfide corrosion, acid rain, and atmospheric degradation
- Molybdenum-Alloyed Variants — SUS316 grade contains 2–3% Molybdenum (Mo) for enhanced resistance to pitting and crevice corrosion in chloride-containing environments
- Stabilized Grades — Ti-stabilized (SUS321) and Nb-stabilized (SUS347) options available for high-temperature service conditions
Key Performance Properties
- Thermal Conductivity — 14.6–16.3 W/(m·K) at 20°C, providing reliable heat transfer performance
- Operating Temperature Range — −196°C to +870°C, accommodating cryogenic to high-temperature applications
- Yield Strength — ≥205 MPa (0.2% offset), ensuring structural integrity under thermal cycling
- Tensile Strength — 515–720 MPa, providing robust mechanical performance
- Thermal Expansion Coefficient — 16–18 × 10⁻⁶/°C, compatible with standard thermal management design parameters
- Non-magnetic Properties — Austenitic structure ensures non-magnetic behavior in service
Specifications
| Parameter | Specification |
|---|---|
| Product Designation | Stainless Steel Coil Tube (Coiltube) |
| Material Grades | SUS304 / SUS316 / SUS321 / SUS347 / Custom |
| Outer Diameter (OD) | 14 mm – 114.3 mm (½" – 4½" NPS) |
| Wall Thickness | 0.8 mm – 6.0 mm (ASME B36.19M / ASTM A269) |
| Coil Diameter | 300 mm – 3,000 mm (configurable per application) |
| Coil Pitch / Spacing | 50 mm – 200 mm (optimized for heat transfer efficiency) |
| Tube Length (Uncoiled) | Up to 500 m continuous length |
| Surface Finish | No. 4 Brushed / BA (Bright Annealed) / Polished |
| End Preparation | Beveled / Plain / Threaded / Flanged (per customer specification) |
| Pressure Rating | Up to 4.0 MPa (depending on OD and wall thickness) |
| Winding Accuracy | ±1.5% of nominal coil diameter |
| Dimensional Tolerance | ±0.1 mm (OD) / ±10% (wall thickness) |
| Heat Medium | Hot water / Steam / Thermal oil (up to 300°C) |
Manufacturing Process
Production Workflow
- Raw Material Selection & Inspection — Certified stainless steel seamless or welded pipe stock is procured from approved mills. Incoming materials undergo spectroscopic analysis (PMI), visual inspection, and dimensional verification per ASTM A999.
- Cutting & Preparation — Tube stock is cut to required lengths with precision saws, followed by end deburring and chamfering to ensure proper fitting compatibility.
- Forming & Coil Winding — Using computer-controlled coil winding machinery, tubes are formed into precise helical patterns with controlled pitch, diameter, and twist parameters. The winding process maintains consistent curvature radii to prevent material stress concentrations.
- Heat Treatment (if required) — Solution annealing at 1040–1120°C followed by rapid quenching to restore full austenitic microstructure, relieve residual stresses, and maximize corrosion resistance.
- Surface Treatment — Pickling and passivation to remove mill scale and form a protective chromium oxide film, ensuring long-term corrosion protection.
- Non-Destructive Testing (NDT) — Hydrostatic pressure testing per ASTM A269/A270 standards; visual inspection of all welds and bends; optional Eddy Current Testing (ECT) for weld integrity verification.
- Final Dimensional Inspection — Verification of coil diameter, pitch accuracy, tube OD/wall thickness, and overall geometry against engineering drawings.
Quality Control Measures
- In-process inspection at every manufacturing stage with documented traceability
- Third-party inspection available (SGS, BV, TUV)
- Full material traceability from mill certificate through final shipment
- Compliance with ISO 9001:2015 Quality Management System
Applications
Primary Application Domain
Floating Roof Oil Tank Heating Systems — The principal application for this coil tube product is the heating of petroleum products stored in floating roof storage tanks. As validated through numerical simulation studies, these coil tubes are immersed in the stored product to maintain optimal temperature, preventing wax crystallization, ensuring proper viscosity for pumping operations, and maintaining product quality during storage.
Additional Applications
- Petrochemical Storage — Heating of heavy crude oils, fuel oils, bitumen, and other high-viscosity petroleum products
- Chemical Processing — Immersion heating of reactive chemicals, polymers, and specialty fluids in process vessels
- Food & Pharmaceutical Industry — Sanitary-grade heating coils for food-grade liquids and pharmaceutical solutions (SUS316L grade)
- Marine Applications — Fuel tank heating systems on vessels operating in cold-climate regions
- Environmental Systems — Heating elements for wastewater treatment and sludge management facilities
- Refinery Operations — Product heating in transfer pipelines, surge tanks, and metering skids
Design Considerations for Oil Tank Applications
Numerical simulation studies of the floating roof oil tank coil tube heating process have demonstrated that optimal thermal performance is achieved through careful selection of coil geometry, pitch spacing, and tube diameter relative to tank dimensions and product thermal properties. The simulation results confirm that stainless steel coil tubes provide uniform heat distribution, minimize thermal stratification, and reduce energy consumption by 15–25% compared to conventional heating methods.
Quality Certifications & Standards Compliance
Applicable Standards
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing
- ASTM A270 — Standard Specification for Seamless, Cold-Drawn Austenitic Stainless Steel Tubes
- ASTM A999 — Standard Specification for Chemical Analysis Reporting for Wrought and Cast Stainless Steel Products
- ASME B36.19M — Welded and Seamless Wrought Stainless Steel Pipe
- EN 10216-5 — Non-alloy and Alloy Steel Tubes for Mechanical and Technical Purposes
- GB/T 12771 — Stainless Steel Seamless Tubes for Fluid Transport (Chinese National Standard)
- GB/T 14976 — Cold-Drawn Stainless Steel Tubes for Fluid Transport
Certifications Held
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System
- CE Marking — European Conformity for pressure equipment
- NACE MR0175 / ISO 15156 — Resistance to Sulfide Stress Cracking for oil and gas industry
- PED (Pressure Equipment Directive 2014/68/EU) — Compliance for pressure-containing equipment
- Mill Test Certificates (MTC) — EN 10204 Type 3.1 for each shipment
Unique Selling Points
- Simulation-Validated Performance — Product design informed by rigorous numerical simulation of heating processes in floating roof oil tanks, ensuring optimal thermal efficiency and reliability
- Customizable Geometry — Coil diameter, pitch, tube size, and total length can be precisely tailored to specific tank dimensions and thermal requirements
- Superior Corrosion Resistance — Austenitic stainless steel construction provides decades of service life even in aggressive petroleum environments containing sulfur compounds
- Energy Efficiency — Maximized heat transfer surface area with minimized thermal losses, reducing overall energy consumption in tank heating operations
- Full Traceability — Complete material and manufacturing traceability from raw material to final product, ensuring compliance with international regulatory requirements
- Scalable Solutions — Available in configurations ranging from small pilot tanks to large-scale commercial storage facilities with capacities exceeding 100,000 barrels