Stainless Steel Heat Extraction Coil Tube (Regenerator Application)
Product Overview
The Stainless Steel Heat Extraction Coil Tube (Product No. 1429) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a specialized coiled piping system designed for high-temperature heat extraction duties within catalytic cracking regenerator units and analogous industrial thermal processes. This coil tube is engineered to endure extreme thermal cycling, corrosive flue gas environments, and mechanical fatigue conditions inherent to continuous regeneration operations in petrochemical and refining facilities.
Based on comprehensive failure analysis of heat extraction coil tubes in regenerator service, this product incorporates advanced metallurgical formulations and precision manufacturing techniques to mitigate common degradation mechanisms including carburization, intergranular corrosion, thermal fatigue cracking, and erosion-corrosion synergy. The coil tube represents a critical heat transfer component that extracts thermal energy from regenerator flue gas, thereby maintaining optimal regeneration temperature and protecting downstream equipment from thermal damage.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel alloys specifically selected for resistance to high-temperature oxidation, carburization, and sulfidation. The primary material grades include:
- 310/310S (UNS S31008/S31009): Chromium-Nickel austenitic stainless steel with elevated chromium content (24-26% Cr) and nickel content (19-22% Ni), providing superior resistance to thermal cycling and oxidation at temperatures up to 1150°C.
- 309/309S (UNS S30908/S30909): Chromium-Nickel austenitic stainless steel (23-25% Cr, 12-15% Ni) offering excellent resistance to oxidation and carburization in oxidizing and carburizing atmospheres.
- 321/321H (UNS S32100/S32109): Titanium-stabilized austenitic stainless steel (17-19% Cr, 9-12% Ni, 5×C Ti) providing enhanced resistance to intergranular corrosion and stress corrosion cracking.
- 904L (UNS N08904): High-alloy austenitic stainless steel (20% Cr, 25% Ni, 4.5% Mo) for severe corrosive environments with high sulfur and chloride content.
Key Mechanical Properties (Typical at 650°C)
- Yield Strength: ≥ 138 MPa (20 ksi)
- Tensile Strength: ≥ 205 MPa (30 ksi)
- Elongation: ≥ 40% (in 50 mm gauge length)
- Thermal Conductivity: 20-25 W/(m·K)
- Coefficient of Thermal Expansion: 16-18 × 10⁻⁶ /°C
- Maximum Service Temperature: 1100°C (continuous), 1150°C (intermittent)
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Heat Extraction Coil Tube |
| Product Number | 1429 |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Outer Diameter (OD) | Φ25 mm – Φ114.3 mm (customizable) |
| Wall Thickness | 2.0 mm – 8.0 mm (based on pressure/temperature rating) |
| Coil Diameter | 300 mm – 3000 mm (customizable per design) |
| Material Grade | 310S, 309S, 321H, 904L, or equivalent |
| Temperature Range | -40°C to 1100°C (continuous service) |
| Pressure Rating | Up to 16 MPa (design dependent) |
| Surface Finish | Mill finish or polished (Ra ≤ 0.8 μm) |
| Standard Compliance | ASTM A213/A269, GB/T 12771, EN 10216-5 |
| End Treatment | Plain end, beveled, threaded, or flanged |
| Heat Treatment | Solution annealed and water quenched |
| Maximum Operating Temperature | 1100°C (oxidizing atmosphere) |
| Design Life | ≥ 10 years (under specified operating conditions) |
Manufacturing Process
The coil tube manufacturing process at Wenzhou Jixing Metal Materials Co., Ltd. follows rigorous quality control protocols to ensure product integrity and service reliability:
- Raw Material Selection: Certified stainless steel seamless tubes or precision-welded tubes sourced from qualified mills, with full chemical composition and mechanical property verification per ASTM/GB standards.
- Heat Treatment: Solution annealing at 1050-1150°C followed by rapid water quenching to achieve a fully austenitic microstructure free of carbide precipitation and residual stress.
- Coiling: Precision cold or warm coiling using CNC-controlled winding machines with calibrated tension control to prevent work hardening, distortion, or micro-cracking at bend radii. Minimum bend radius maintained at 3D (diameter) or greater.
- Welding: Where required, joints are fabricated using Gas Tungsten Arc Welding (GTAW) or Shielded Metal Arc Welding (SMAW) with matching filler metals. All welds undergo 100% visual inspection and radiographic testing (RT) per ASME Section IX.
- Surface Preparation: Pickling and passivation treatment to remove scale, oxide layers, and surface contamination, ensuring a clean, corrosion-resistant chromium oxide film.
- Quality Inspection: Comprehensive testing including hydrostatic pressure testing (1.5× design pressure), dimensional verification, hardness testing, and non-destructive examination (NDT) including ultrasonic testing (UT) and dye penetrant testing (PT).
- Post-Coil Heat Treatment: Optional stress-relief annealing at 900-1000°C to eliminate residual stresses introduced during the coiling process, enhancing long-term resistance to thermal fatigue and stress corrosion cracking.
Applications
The Heat Extraction Coil Tube is designed for demanding industrial applications where reliable heat transfer under extreme conditions is critical:
- Catalytic Cracking Regenerators (FCC): Primary application — heat extraction coils installed in fluid catalytic cracking regenerator drums to control regeneration temperature and recover thermal energy from catalyst burnout.
- Visbreaking Units: Thermal energy extraction in vacuum visbreaking and thermal cracking processes.
- Coke Oven Heat Recovery: High-temperature flue gas heat extraction in coking operations.
- Petrochemical Reactors: Internal heat extraction coils in exothermic reaction vessels to maintain isothermal conditions.
- Power Generation: Supercritical and ultra-supercritical boiler components, economizer coils, and air preheater tubes.
- Chemical Processing: Heat exchangers and reactor internals in chlor-alkali, sulfuric acid, and nitric acid production.
- Environmental Systems: Flue gas desulfurization (FGD) and selective catalytic reduction (SCR) system components.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and complies with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System Certification
- NACE MR0175/ISO 15156 — Compliance for oil and gas industry materials
- ASME Section IX — Welding qualification and certification
- API Q1/Q2 — Quality management for oil and gas equipment
- EN 10204 3.1/3.2 — Inspection certificate compliance
- TÜV / SGS / BV — Third-party inspection and verification
All products are accompanied by mill test certificates (MTC) including full chemical analysis, mechanical property data, and traceability documentation in accordance with EN 10204 Type 3.1 or 3.2 requirements.
Unique Selling Points
- Failure-Informed Design: Product specifications are derived from comprehensive failure analysis of regenerator heat extraction coil tubes, incorporating lessons learned from real-world service degradation including carburization, thermal fatigue cracking, and erosion-corrosion mechanisms.
- Extended Service Life: Advanced metallurgical optimization and post-coiling stress relief treatment provide design life exceeding 10 years, significantly reducing unplanned shutdowns and maintenance costs.
- Custom Engineering Capability: Flexible manufacturing to accommodate custom OD, wall thickness, coil diameter, and material grade requirements based on specific process design parameters.
- Full Traceability: Complete material and manufacturing traceability from raw material mill certification through final product delivery, ensuring accountability at every stage.
- Comprehensive NDT Coverage: 100% radiographic testing of all welds, hydrostatic pressure testing, and dimensional verification ensuring zero-defect delivery.
Technical Note: The selection of appropriate material grade and specification should be based on detailed process conditions including maximum operating temperature, flue gas composition (SO₂, CO₂, CO, H₂O, O₂, Cl⁻, and particulate content), pressure rating, thermal cycling frequency, and design life requirements. Wenzhou Jixing Metal Materials Co., Ltd. provides engineering consultation services to optimize material selection for specific application conditions.