Stainless Steel Coil Tube for Regenerator Heat Extraction Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product specifically designed for high-temperature heat extraction applications within regenerator systems. These coil tubes serve as critical heat exchange elements in fluid catalytic cracking (FCC) units, catalytic reformers, and other petrochemical regeneration processes where efficient thermal management and extended service life are paramount.
Based on extensive field studies regarding the service life challenges of regenerator internal heat extraction coil tubes, Wenzhou Jixing has developed a specialized product line that addresses the key failure mechanisms—including thermal fatigue, oxidative scaling, and thermal stress cracking—that commonly limit the operational lifespan of conventional coil tubes in aggressive regenerator environments.
Material & Properties
The coil tubes are fabricated from high-performance austenitic and duplex stainless steel grades selected for their superior resistance to thermal cycling, oxidation, and mechanical degradation under continuous high-temperature service conditions.
- Primary Grades: AISI 310S (UNS S31008), AISI 309 (UNS S30908), AISI 347 (UNS S34700), and Super 310H (UNS S31058)
- Key Properties:
- Operating temperature range: up to 1150°C (2094°F) for Super 310H grades
- Excellent thermal fatigue resistance under cyclic heating and cooling conditions
- Outstanding oxidation resistance with stable protective chromium oxide scale formation
- High-temperature creep strength and stress rupture life
- Resistance to sulfur-induced stress corrosion cracking (SCC)
- Maintained ductility and toughness at elevated service temperatures
Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 25 mm – 159 mm (customizable) | ASTM A213 / ASME SA-213 |
| Wall Thickness | 1.5 mm – 12.0 mm | ASTM A213 |
| Bend Radius | 3D – 6D (D = tube OD) | ASME B31.3 |
| Coil Length | 5 m – 50 m (continuous) | Customer-specific | Surface Finish | Mechanically polished, Ra ≤ 1.6 μm | ASTM A270 |
| Heat Treatment | Solution annealed + pickled & passivated | ASTM A213 |
| End Condition | Plain, beveled, threaded, or flanged | ASME B1.20.1 |
| Maximum Operating Temperature | 1100°C (Super 310H) / 1000°C (310S) | Material datasheet |
| Design Pressure | Up to 15.0 MPa (2175 psi) | ASME B31.3 |
| Service Life (Target) | ≥ 8000 hours continuous operation | Based on field performance data |
Manufacturing Process
The production of these specialized coil tubes follows a rigorous multi-stage manufacturing workflow designed to ensure dimensional accuracy, metallurgical integrity, and long-term service reliability:
- Raw Material Selection & Inspection: Ingot or strip material is sourced from certified mills with full chemical composition verification (spectrometric analysis) and mechanical property validation.
- Coil Forming (Cold or Hot): Precision-bent coil geometry is achieved through CNC-controlled coiling machines. Cold forming is employed for diameters below 76 mm; hot forming is utilized for larger diameters and thicker wall sections to prevent work-hardening and microstructural degradation.
- Intermediate Heat Treatment: Post-forming stress relief annealing at 1050–1150°C in a controlled atmosphere (argon or vacuum) eliminates residual bending stresses and restores full grain structure.
- Surface Preparation: Mechanical polishing followed by chemical pickling and passivation to remove scale, contaminants, and to establish a uniform chromium-rich passive film.
- Dimensional Verification: Laser-based measurement systems confirm OD, wall thickness, bend radius, and overall coil geometry within specified tolerances (±0.05 mm for critical dimensions).
- Non-Destructive Testing (NDT): 100% eddy current testing (ECT) and ultrasonic testing (UT) to detect internal and surface discontinuities. Hydrostatic pressure testing at 1.5× design pressure per ASME B31.3 requirements.
- Final Inspection & Packaging: Each coil tube is individually identified, traceable to mill heat numbers, and packaged with protective end caps and moisture-absorbent materials for shipment.
Applications
These stainless steel coil tubes are engineered for demanding thermal management applications across multiple industrial sectors:
- Petrochemical Industry:
- Fluid Catalytic Cracking (FCC) regenerator heat extraction systems
- Catalytic reformer feed preheating coils
- Hydrocracker regenerator heat recovery units
- Fluidized bed reactor thermal control elements
- Power Generation:
- Waste heat recovery boilers (WHRB) in combined cycle power plants
- Gas turbine exhaust heat extraction systems
- Specialty Applications:
- High-temperature process heaters in chemical plants
- Calcination kiln heat extraction systems
- Industrial furnace heat transfer coils
- Regenerator internal cooling systems in metallurgical processes
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring full compliance with international standards:
- Quality Management: ISO 9001:2015 certified manufacturing and quality assurance systems
- Product Standards: Full compliance with ASTM A213 (Seamless Stainless Steel Tubing), ASME SA-213, and EN 10216-5
- Pressure Vessel Standards: ASME Section VIII Division 1 (where applicable for system integration)
- Industry Certifications: API 5CT (for oil and gas sector applications), PED (Pressure Equipment Directive 2014/68/EU) compliance for European market
- Testing & Inspection: Third-party inspection available per Lloyd's Register (LR), DNV, or Bureau Veritas protocols
- Material Traceability: Full heat-number traceability with mill test certificates (MTC) per EN 10204 Type 3.1
Unique Selling Points
Extended Service Life Engineering: Drawing upon extensive field data analysis regarding regenerator coil tube failure modes, Wenzhou Jixing has incorporated metallurgical optimizations—including controlled carbon content, niobium stabilization, and optimized grain size—that demonstrably extend operational life beyond 8000 hours in continuous service, addressing the critical service life challenges identified in industry literature.
Thermal Fatigue Resistance: The specialized heat treatment protocols and material selection provide superior resistance to the cyclic thermal stress conditions inherent in regenerator heat extraction applications, significantly reducing the incidence of thermal fatigue cracking.
Custom Geometry Capability: Flexible manufacturing capacity accommodates custom coil geometries, bend radii, and dimensional configurations tailored to specific regenerator design requirements.