Stainless Steel Coil Tube for Shell Gasifier Quenching System
Product Overview
The Stainless Steel Coil Tube (Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered heat exchanger component specifically designed for the quenching (cooling) section of Shell SCOT (Stable Catalyst Ortho Transfer) gasification reactors. These coil tubes serve as critical cooling elements within the quenching port, where they facilitate rapid heat transfer between the hot syngas stream and the quench water, thereby controlling the outlet gas temperature and protecting downstream equipment from thermal degradation.
Based on extensive field failure analysis and improvement studies, these coil tubes are engineered to withstand extreme thermal cycling, high-velocity water erosion, and corrosive chemical environments simultaneously — a unique combination of service conditions that demands exceptional material integrity and manufacturing precision.
Material & Properties
The coil tubes are fabricated from high-grade austenitic stainless steel alloys, primarily selected from the following grades to ensure long-term durability under the demanding quenching service conditions:
- AISI 316L (UNS S31603) — Enhanced corrosion resistance with low carbon content for improved weldability and resistance to intergranular corrosion.
- AISI 321 (UNS S32100) — Titanium-stabilized grade offering superior resistance to thermal stress cracking and oxidation at elevated temperatures.
- AISI 310S (UNS S31008) — High-temperature grade with excellent oxidation resistance for extreme thermal exposure scenarios.
Key Material Properties:
- Operating temperature range: −40 °C to +900 °C (depending on alloy grade)
- Resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC)
- Outstanding thermal fatigue resistance under repeated thermal cycling
- Low carbon content (<0.03% C) to prevent carbide precipitation at weld zones
- High ductility and formability enabling precise coil winding without work-hardening defects
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube for Gasifier Quenching Port |
| Material Grade | AISI 316L / 321 / 310S (customizable) |
| Outer Diameter (OD) | Φ12 mm – Φ51 mm (standard); custom sizes available |
| Wall Thickness (WT) | 0.5 mm – 3.0 mm (tolerance ±0.1 mm) |
| Coil Diameter (Bend Diameter) | Φ150 mm – Φ600 mm (configurable per design) |
| Coil Pitch | 15 mm – 50 mm (adjustable) |
| Surface Finish | Pickled and Passivated (P&P); Ra ≤ 0.8 μm |
| Maximum Operating Pressure | Up to 4.0 MPa (gauge) |
| Maximum Operating Temperature | Up to 900 °C (gas side); up to 250 °C (water side) |
| Tensile Strength (UTS) | ≥ 520 MPa (316L); ≥ 515 MPa (321) |
| Yield Strength (0.2% offset) | ≥ 205 MPa (316L); ≥ 205 MPa (321) |
| Elongation (A50mm) | ≥ 40% |
| Thermal Conductivity | 14.9 W/(m·K) at 100 °C (316L) |
| Heat Treatment | Solution Annealed at 1050 °C – 1150 °C, followed by water quenching |
| Standard Compliance | ASTM A269 / ASTM A312 / ASME B36.19M / EN 10217 |
Manufacturing Process
The production of these specialized coil tubes follows a rigorous multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and long-term service reliability:
- Raw Material Selection & Inspection — Certified stainless steel seamless tubes are procured from approved mills with full mill test certificates (MTC). Incoming material undergoes spectroscopic verification (PMI — Positive Material Identification) and ultrasonic testing (UT) for internal defects.
- Dimensional Preparation — Tubes are cut to required lengths with precision plasma or laser cutting. Ends are deburred and chamfered to facilitate coil winding and subsequent welding.
- Coil Winding (Forming) — Cold or warm-forming techniques are employed on precision CNC coil winding machines to achieve the specified coil geometry. Winding is performed at controlled speeds to minimize residual stress and prevent micro-cracking at bend regions.
- Stress Relief Annealing — Post-forming annealing at 850 °C – 950 °C eliminates residual stresses introduced during cold forming, restoring full ductility and preventing delayed cracking.
- Welding — End-to-end welds and connections to header manifolds are performed using GTAW (Gas Tungsten Arc Welding) with inert gas shielding (Ar or Ar/He mixtures). Weld consumables are matched to the base metal grade.
- Non-Destructive Testing (NDT) — 100% visual inspection (VT), 100% dye penetrant testing (PT) on all welds, and radiographic testing (RT) on critical joints ensure weld integrity.
- Pickling & Passivation — Chemical pickling removes heat-affected zone discoloration and oxide scale. Passivation treatment establishes a stable chromium oxide film for maximum corrosion resistance.
- Hydrostatic Pressure Testing — Each coil assembly is pressure-tested at 1.5× the maximum operating pressure to verify leak-tightness and structural soundness.
- Final Inspection & Packaging — Dimensional verification, surface finish measurement, and material traceability documentation are completed. Products are packaged in moisture-protected containers with individual certificates.
Applications
These stainless steel coil tubes find their primary application in the following industrial sectors:
- Shell Gasifier Quenching Systems — Primary application as cooling coils within the quenching port of Shell SCOT gasifiers, where they rapidly cool syngas from ~1,300 °C to ~600 °C using quench water spray.
- Petrochemical Gasification — Coal-to-liquids (CTL), coal-to-gas (CTG), and gas-to-liquids (GTL) conversion processes requiring robust heat exchange in aggressive environments.
- Hydrogen Production — Steam methane reforming (SMR) and autothermal reforming (ATR) units where thermal cycling resistance is paramount.
- Refinery Upgrading — Hydrocracking and coker units with high-temperature cooling requirements.
- Power Generation — Integrated gasification combined cycle (IGCC) power plants.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management System
- API Q1 (Q90/Q91) — Quality management for oil and gas industry products
- PED 2014/68/EU — Pressure Equipment Directive compliance (Category II/III)
- ASME Stamp — Section VIII Div. 1 for pressure vessel components
- EN 10204 3.1 — Material test certificates with independent third-party inspection
- TÜV / SGS Third-Party Inspection — Available upon customer request
Note: All products are supplied with a full traceability package including mill test certificates, heat numbers, chemical composition analysis, mechanical property reports, NDT reports, and dimensional inspection records to ensure complete material traceability from raw stock to finished product.
Unique Selling Points & Technical Advantages
- Failure-Informed Design: Product specifications are continuously refined based on extensive field failure analysis of Shell gasifier quenching port coil tubes, incorporating lessons learned from real-world erosion-corrosion damage, thermal fatigue cracking, and water hammer effects.
- Enhanced Erosion Resistance: Optimized wall thickness profiles and surface treatments specifically address high-velocity quench water erosion, a primary failure mechanism identified in field studies.
- Thermal Fatigue Optimization: Material selection and heat treatment protocols are tailored to withstand the extreme thermal cycling inherent in gasifier quenching operations (repeated exposure to >1,000 °C gas and ~50 °C water).
- Custom Engineering: Flexible design capability to accommodate specific gasifier configurations, coil geometries, and spatial constraints within the quenching vessel.
- Full Traceability: Complete material and process documentation enabling root-cause analysis and predictive maintenance planning for end-users.