Spiral Coil Tube for Built-In Cold Slag Cooler
Product Overview
The Spiral Coil Tube (盘管, Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered stainless steel tubing product specifically designed for integration into built-in spiral coil-type cold slag coolers (内置螺旋盘管式冷渣器). These coolers are critical heat-recovery and slag-quenching components employed in waste-to-energy incinerators, solid waste treatment plants, and industrial metallurgical processes. The coil tube serves as the primary heat-exchange element, transferring thermal energy from molten slag to a circulating working fluid (typically water or steam), thereby enabling efficient slag cooling, energy recovery, and safe slag disposal.
This product addresses the well-documented engineering challenge of cavitation (汽蚀) in spiral coil-type cold slag coolers — a phenomenon caused by localized pressure drops leading to vapor bubble formation and subsequent implosive collapse on the tube wall, resulting in material degradation, vibration, noise, and reduced service life. Wenzhou Jixing's coil tubes are engineered with optimized geometry, wall thickness profiles, and surface treatments to mitigate cavitation erosion and extend operational reliability.
Material & Properties
The coil tube is fabricated from high-performance austenitic and duplex stainless steel grades, selected to withstand the extreme thermal cycling, corrosive slag environments, and mechanical stresses inherent in cold slag cooler service.
- Primary Grades: SUS304 (UNS S30400), SUS316L (UNS S31603), SUS321 (UNS S32100), and Duplex 2205 (UNS S31803) depending on service conditions.
- Corrosion Resistance: Excellent resistance to acidic slag compositions (containing SO₃, H₂S, HCl, and HF), high-temperature oxidation, and intergranular corrosion.
- Thermal Stability: Maintains mechanical integrity under repeated thermal cycling between ambient temperature and slag temperatures up to 1,400 °C (2,552 °F).
- Mechanical Properties: Minimum tensile strength of 520 MPa (SUS304) to 620 MPa (Duplex 2205); elongation ≥ 40% (SUS304) to ≥ 25% (Duplex 2205).
- Cavitation Resistance: Enhanced surface hardness and microstructural uniformity through controlled cold-work and solution heat treatment reduce susceptibility to cavitation erosion.
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Spiral Coil Tube for Cold Slag Cooler |
| Product Code | #989 — Coiltube |
| Outer Diameter (OD) | 12 mm – 51 mm (customizable) |
| Wall Thickness | 1.0 mm – 4.0 mm (graded profile available) |
| Helix Diameter | 200 mm – 1,200 mm |
| Pitch (Helix Spacing) | 15 mm – 60 mm |
| Coil Length | Up to 30 m per continuous coil (seamless or welded) |
| Material Grades | SUS304, SUS316L, SUS321, Duplex 2205, Inconel 625 |
| Surface Finish | Mill finish, polished (Ra ≤ 0.4 μm), or passivated |
| Welding Method | TIG (GTAW) or orbital welding; full-penetration welds |
| Operating Temperature Range | -40 °C to +600 °C (continuous) |
| Design Pressure | Up to 2.5 MPa (working fluid side) |
| Standards Compliance | ASTM A213, ASTM A269, EN 10216-5, GB/T 12771 |
| Minimum Order Quantity | 50 m or 20 coils (negotiable) |
Manufacturing Process
- Raw Material Selection & Inspection: Certified stainless steel seamless or welded tube stock is sourced from approved mills. Incoming material undergoes chemical composition analysis (OES), mechanical testing, and visual inspection per ASTM E415 and ASTM E334.
- Heat Treatment: Solution annealing at 1050 °C – 1150 °C followed by controlled air or water quenching to achieve a fully austenitic microstructure with optimal corrosion and cavitation resistance. Duplex grades undergo stabilized annealing at 1000 °C – 1050 °C.
- Dimensional Forming & Helix Coiling: Tubes are cold-formed or hot-formed into precise helical geometry using CNC-controlled coiling machinery. Forming parameters are calibrated to avoid excessive work-hardening and to maintain uniform wall thickness throughout the coil. The helix pitch and diameter are controlled to within ±0.5 mm tolerance.
- Welding & Joining: End connections and any intermediate splices are performed via Gas Tungsten Arc Welding (GTAW/TIG) with inert gas shielding. Weld parameters are optimized to minimize heat-affected zone (HAZ) sensitization. Post-weld passivation is applied to restore passive film integrity.
- Surface Treatment & Anti-Cavitation Coating: Optional internal/external surface polishing to Ra ≤ 0.4 μm reduces nucleation sites for cavitation bubble formation. Specialized ceramic or PTFE-based anti-cavitation coatings may be applied to high-stress zones as an additional protective measure.
- Quality Inspection & Testing: Every coil undergoes 100% visual inspection, dimensional verification, hydrostatic pressure testing (at 1.5× design pressure for 30 minutes), and optional eddy current or ultrasonic testing (ET/UT) for wall thickness uniformity and defect detection.
- Packaging & Dispatch: Coils are packaged on wooden reels with moisture-absorbing desiccants, wrapped in protective film, and clearly labeled with material certificates and traceability codes.
Applications
- Municipal Solid Waste Incineration (MSWI): Built-in spiral coil-type cold slag coolers in waste-to-energy plants, where molten slag (typically 1,200 °C – 1,400 °C) is rapidly quenched to enable safe mechanical handling and disposal.
- Industrial Waste Heat Recovery: Integration into heat-recovery steam generators (HRSG) for power generation from incineration exhaust gases.
- Metallurgical Slag Treatment: Slag quenching systems in steel mills, foundries, and non-ferrous metal processing facilities.
- Chemical & Petrochemical Industry: High-temperature heat exchangers and reactor cooling loops requiring corrosion-resistant spiral coil configurations.
- Power Generation: Auxiliary cooling systems in coal-fired and biomass power plants.
Quality Certifications & Compliance
- ISO 9001:2015 — Quality Management System certification for manufacturing processes.
- ISO 14001:2015 — Environmental Management System certification.
- ISO 45001:2018 — Occupational Health and Safety Management System.
- ASME / NB Certification — Pressure vessel and piping component compliance where applicable.
- CE Marking — European conformity for pressure equipment directive (PED 2014/68/EU).
- Material Certificates: EN 10204 3.1 mill test certificates (MTC) provided with every shipment; 3.2 certificates available upon request.
- Third-Party Inspection: Optional inspection by SGS, Bureau Veritas, or TÜV during manufacturing.
Unique Selling Points
1. Anti-Cavitation Engineering: Drawing directly from documented field experience with cavitation failure modes in built-in spiral coil-type cold slag coolers, Wenzhou Jixing applies optimized helix geometry, graded wall thickness, and surface finish specifications that demonstrably reduce cavitation erosion rates by up to 60% compared to standard coil tubes.
2. Thermal Cycling Durability: Materials and heat treatment protocols are specifically validated for thousands of thermal cycles between ambient and slag temperatures, ensuring long-term dimensional stability and fatigue resistance.
3. Customizable Geometry: Full parametric customization of helix diameter, pitch, tube OD, and wall thickness enables precise matching to specific cooler designs and process conditions.
4. Full Traceability: Each coil is traceable to its mill heat number, with complete documentation of chemical composition, mechanical properties, heat treatment records, and inspection results.
5. Technical Consultation: Wenzhou Jixing provides engineering support for coil layout design, cavitation risk assessment, and material selection optimization tailored to the customer's specific operating environment.