Stainless Steel Spiral Coil Tube — Synthesis Gas Cooler/Evaporator Application

Product Overview

The Stainless Steel Spiral Coil Tube (Product No. 441) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered heat transfer component designed for demanding process environments, particularly within Shell-type furnace synthesis gas coolers and evaporators (also referred to as waste heat recovery units). These coil tubes serve as the critical internal heat exchange element, facilitating the transfer of thermal energy from high-temperature synthesis gas streams to process water or feedstock, thereby enabling efficient temperature reduction and heat recovery in petrochemical and hydrogen production facilities.

Engineered in accordance with the operational and maintenance requirements outlined in the Shell Furnace Synthesis Gas Cooler/Evaporator Spiral Coil Tube Inspection and Maintenance Plan, these coil tubes are specifically optimized for continuous-duty service under fluctuating thermal loads, high-pressure differentials, and corrosive process media environments.

Material & Properties

The coil tubes are fabricated from high-grade austenitic and super-austenitic stainless steel alloys selected to withstand the aggressive conditions encountered in synthesis gas processing:

Base Materials: SUS304 (ASTM A268 TP304), SUS304L (ASTM A268 TP304L), SUS316 (ASTM A268 TP316), SUS316L (ASTM A268 TP316L), SUS321 (ASTM A268 TP321), and SUS347 (ASTM A268 TP347)
Specialty Alloys: Alloy 625 (UNS N06625), Alloy 800H (UNS N08810), Alloy C-276 (UNS N10276) available upon specification for extreme chloride and sulfur-bearing environments
Corrosion Resistance: Exceptional resistance to intergranular corrosion, pitting, crevice corrosion, and stress corrosion cracking (SCC) under high-temperature aqueous and gaseous conditions
Thermal Properties: Low thermal expansion coefficient; maintains dimensional stability across operating temperature ranges of −40°C to +1200°C depending on alloy grade
Mechanical Properties: High yield strength and tensile strength retention at elevated temperatures; resistance to thermal fatigue cycling
Hygienic & Surface Quality: Available in cold-rolled (2B finish), polished (BA finish), or pickled and passivated surface conditions for optimal heat transfer efficiency

Specifications

Parameter	Specification	Standard / Reference
Product Designation	Stainless Steel Spiral Coil Tube	—
Product Code	No. 441	Internal Catalog
Coil Configuration	Spiral (helical) / Helical coil winding	ASTM A268, EN 10217-7
Outer Diameter (OD)	19 mm – 168 mm (customizable)	ASTM B366 / B89
Wall Thickness	0.5 mm – 12 mm (customizable)	ASTM B366 / B89
Coil Diameter (CD)	300 mm – 5000 mm (customizable)	Project-specific
Coil Length	Up to 500 m per continuous coil	—
Pitch (Coil Spacing)	1.5×OD to 3×OD (configurable)	ASME B31.3
Operating Temperature Range	−40°C to +1200°C (alloy-dependent)	ASTM A268
Operating Pressure	Up to 42 MPa (design-dependent)	ASME BPVC Section VIII
End Preparation	Plain end, beveled end, or flanged connection	ASME B16.25 / B16.1
Surface Finish	2B, BA, Pickled & Passivated, Ra ≤ 0.4 μm (polished)	ASTM A403
Tolerance — OD	±0.02 mm to ±0.15 mm (depending on diameter)	ASTM A268
Tolerance — Wall Thickness	±10% of nominal (or tighter per specification)	ASTM A268
Winding Tolerance	±1% of nominal coil diameter; ±0.5 mm pitch deviation	Internal QA Protocol
Heat Treatment	Solution annealed (1050°C – 1150°C) + rapid quench	ASTM A268
Test Methods	Hydrostatic test, eddy current, ultrasonic (UT), radiographic (RT)	ASTM E165, E309, E94

Manufacturing Process

The production of the Spiral Coil Tube follows a rigorously controlled multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and long-term service reliability:

Material Procurement & Incoming Inspection: Raw stainless steel pipe stock is sourced from certified mills with full mill test certificates (MTC) compliant with EN 10204 Type 3.1 or Type 3.2. Each lot undergoes chemical composition verification (spectroscopic analysis) and mechanical property testing prior to acceptance.
Material Preparation & Dimensional Verification: Incoming pipe is inspected for dimensional conformance (OD, wall thickness, straightness) using precision measurement instruments. Any non-conforming material is rejected and returned to the supplier.
Solution Annealing: Pipe stock is solution annealed at temperatures between 1050°C and 1150°C followed by rapid water quenching to dissolve carbide precipitates, restore full austenitic microstructure, and maximize corrosion resistance.
Precision Coil Winding (Cold Forming): Annealed pipe is cold-wound onto precision CNC-controlled coil winding machines to produce the required helical geometry. Winding parameters — including coil diameter, pitch, number of turns, and spring-back compensation — are programmed according to engineering drawings and project specifications. Real-time monitoring ensures dimensional tolerances are maintained throughout the winding process.
Post-Forming Stress Relief: Where required by the application, the wound coil undergoes a controlled stress-relief annealing cycle to eliminate residual stresses introduced during cold forming, thereby preventing distortion during subsequent welding and service.
Welding & Joining: End connections, header assemblies, and expansion loop welds are performed using Gas Tungsten Arc Welding (GTAW / TIG) or Orbital TIG welding techniques with matching filler alloys. Welding procedures are qualified per ASME Section IX. Each weld undergoes visual inspection (VT) and, where applicable, radiographic testing (RT) or ultrasonic testing (UT).
Pickling & Passivation: The completed coil assembly is subjected to a chemical pickling and passivation treatment to remove oxide scale, welding discoloration, and surface contaminants, establishing a protective chromium oxide film for enhanced corrosion resistance.
Non-Destructive Testing (NDT): Comprehensive NDT inspection is performed, including eddy current testing (per ASTM E165) for surface defect detection, ultrasonic thickness measurement (per ASTM E797) for wall integrity verification, and hydrostatic pressure testing to validate pressure containment capability.
Final Inspection & Documentation: Each coil tube assembly is inspected against engineering drawings and specifications. Full traceability documentation — including material certificates, heat numbers, weld maps, NDT reports, and dimensional inspection records — is compiled and archived.
Packaging & Dispatch: Coils are wrapped in protective moisture-barrier packaging, secured on wooden skids or cradles, and labeled with identification plates prior to shipment.

Applications

The Stainless Steel Spiral Coil Tube is engineered for a wide range of high-performance thermal and process applications:

Petrochemical Synthesis Gas Cooling: Primary application in Shell-type furnace synthesis gas coolers and evaporators, where the coil tube transfers heat from high-temperature syngas (H₂ + CO + CO₂ mixtures) to process water, enabling gas cooling and steam generation simultaneously.
Waste Heat Recovery Units (WHRU):strong> Integral component in combined-cycle gas turbine (CCGT) systems and steam reforming units, recovering waste heat from exhaust streams for power generation.

Hydrogen Production Facilities: Utilized in water-gas shift converters, methanation reactors, and hydrogen purification systems within ammonia and methanol plants.

Chemical Process Reactors: Applied as internal cooling coils in exothermic reaction vessels (e.g., polymerization reactors, oxidation reactors) to control reaction temperature and prevent thermal runaway.

Power Generation: Employed in heat recovery steam generators (HRSG) and economizer sections of industrial boilers.

Pharmaceutical & Food Processing: Available in high-purity grades (316L, 904L) for sanitary heat exchangers requiring hygienic surface finishes and compliance with FDA/3-A standards.

Marine & Offshore Platforms: Used in condensate coolers, fuel gas coolers, and process heat exchangers on LNG carriers and offshore production facilities.

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd maintains rigorous quality management systems and holds the following certifications and complies with the following international standards:

ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control

ISO 14001:2015 — Environmental Management System certification

ISO 45001:2018 — Occupational Health and Safety Management System certification

ASME — Section VIII Div. 1 (Pressure Vessels), Section IX (Welding Qualification), Section B31.3 (Process Piping)

ASTM — A268 (Welded Austenitic Stainless Steel Tubing), A213 (Tubes, Seamless and Welded), B366 (Welded Austenitic Stainless Steel Tubing for Heat Transfer)

EN — 10217-7 (Welded Tubes for Heat Exchangers), 10204 (Test Documents), 10028 (Pressure Vessels)

API — API 5L / API 5CT (where applicable for upstream applications)

NORSOK — M-640 / M-650 (offshore piping and heat exchanger specifications, where applicable)

Material Traceability: Full heat-number traceability from mill to finished product; EN 10204 Type 3.1 / 3.2 Material Test Certificates provided with every shipment

NDT Certification: Inspection personnel certified per ASNT SNT-TC-1A or ISO 9712 (Level II and above for RT, UT, ET, and PT methods)

Unique Selling Points

Application-Specific Engineering: Coil tubes are designed with direct reference to Shell furnace synthesis gas cooler and evaporator maintenance protocols, ensuring compatibility with established inspection, replacement, and overhaul procedures in petrochemical facilities.

Superior Thermal Fatigue Resistance: Solution-annealed austenitic microstructure provides exceptional resistance to thermal cycling fatigue, extending service life in applications subject to repeated heating and cooling cycles.

Precision Cold-Formed Geometry: CNC-controlled winding ensures tight dimensional tolerances on coil diameter, pitch, and overall length, minimizing installation difficulties and reducing on-site fabrication requirements.

Full Metallurgical Traceability: Every coil tube is traceable to its mill heat number, providing complete material provenance documentation essential for regulatory compliance and insurance purposes.

Customization Capability: Flexible manufacturing capacity allows customization of OD, wall thickness, coil diameter, pitch, alloy grade, and end connections to meet project-specific engineering drawings and specifications.

Comprehensive NDT Coverage: Multi-method non-destructive testing (eddy current, ultrasonic, radiographic, hydrostatic) provides confidence in product integrity prior to dispatch.

Expert Technical Support: Engineering team experienced in Shell furnace and synthesis gas processing applications provides design consultation, installation guidance, and maintenance planning support.

Note: All specifications listed above are representative and subject to modification based on project-specific engineering requirements. Wenzhou Jixing Metal Materials Co., Ltd provides custom-engineered solutions tailored to individual client specifications. For detailed quotation and technical consultation, please submit project drawings, operating conditions (temperature, pressure, media composition), and applicable code requirements.