Stainless Steel Internal Heat Recovery Coil Tube

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd

Product Code: 1617

Classification: Heat Exchange Coil Components

Product Overview

The Stainless Steel Internal Heat Recovery Coil Tube is a precision-engineered product designed specifically for internal heat recovery systems within industrial process vessels, distillation columns, and heat exchanger assemblies. These coil tubes serve as critical heat transfer elements that facilitate thermal energy recovery between process streams, significantly improving overall system energy efficiency and reducing operational costs.

Wenzhou Jixing Metal Materials Co., Ltd specializes in the manufacturing of high-performance coil tubes conforming to international standards for both fabrication quality and installation integrity. The product line encompasses a comprehensive range of coil configurations tailored to diverse industrial applications requiring reliable internal heat recovery solutions.

Material & Properties

Base Material Grades

Mechanical Properties (Typical for Grade 316L)

Corrosion Resistance Characteristics

Specifications

Parameter Specification Standard Reference
Outer Diameter (OD) 12.7 mm – 50.8 mm (1/2" – 2") ASTM A213 / ASTM A269
Wall Thickness 1.0 mm – 5.0 mm (0.039" – 0.197") ASTM A213 / ASTM A269
Coil Diameter (CD) 100 mm – 1500 mm (4" – 60") Custom / Client-Specific
Coil Length Up to 500 m (1640 ft) per continuous coil Manufacturer Specification
Surface Finish Pickled & Passivated (P&P), 2B, or Custom ASTM A403 / ASTM A967
Tolerance on OD ±0.5% (standard); ±0.2% (precision) ASTM A213
Tolerance on Wall Thickness ±10% (standard); ±5% (precision) ASTM A213
Bend Radius (Minimum) 3D – 5D (D = tube OD) ASME B31.3 / B31.1
Seam Type Continuous Welded (TIG / Laser) or Seamless ASTM A213 / ASTM A269
Heat Treatment Solution Annealed at 1050–1150 °C, Water Quenched ASTM A403
End Condition Plain, Beveled, Threaded, or Fitted ASME B31.3
Maximum Working Pressure Up to 25 MPa (3625 psi) depending on dimensions ASME B31.3

Manufacturing Process

1. Material Selection & Incoming Inspection

Raw material selection follows rigorous qualification protocols. Each heat lot of stainless steel coil or pipe stock undergoes chemical composition analysis (OES — Optical Emission Spectroscopy) and mechanical property verification prior to fabrication commencement. Mill test certificates (MTC) conforming to EN 10204 Type 3.1 are obtained for all incoming material.

2. Straightening & Cutting

Coiled stainless steel tubing is fed through precision straightening equipment to achieve straightness tolerances of ≤ 1 mm/m. Cut-off lengths are determined based on the coil layout design, with CNC-controlled cutting ensuring dimensional accuracy within ±0.5 mm.

3. Coil Forming (Cold Bending)

The core manufacturing operation involves cold bending of straightened tubing into the specified helical or spiral coil configuration. This process utilizes:

Maximum acceptable ovalization is limited to 5% of nominal OD, in accordance with ASME B31.3 requirements for formed piping.

4. Welding (if applicable)

For multi-pass or multi-section coils, joining is performed using Gas Tungsten Arc Welding (GTAW/TIG) or Laser Welding. Weld parameters are qualified per ASME Section IX and WPS (Welding Procedure Specification) documentation. Post-weld inspection includes visual examination (VT) and, where required, dye penetrant testing (PT) or radiographic testing (RT).

5. Heat Treatment (if required)

Post-forming stress relief annealing may be applied for applications subject to thermal cycling or cyclic loading. Solution annealing at 1050–1150 °C followed by rapid water quenching restores full austenitic microstructure and eliminates cold-work-induced residual stresses.

6. Surface Treatment & Passivation

All coil tubes undergo pickling and passivation treatment per ASTM A967 to remove scale, oxide films, and foreign metal contamination. Passivation establishes a stable chromium oxide film on the surface, enhancing inherent corrosion resistance. Verification is performed via ferrous particle detection (ASTM A967 Method A) and redox potential testing.

7. Dimensional & Geometric Inspection

Final inspection includes:

Applications

Primary Application Domains

  1. Distillation Column Internal Heat Recovery: Internal heat recovery coils installed within distillation columns to recover heat from vapor streams and pre-heat incoming liquid feed, reducing external energy requirements by 15–30%.
  2. Reactor Cooling Systems: Coils submerged within reactor vessels to remove exothermic heat from chemical reactions while maintaining precise temperature control.
  3. Evaporator & Concentrator Systems: Multi-effect evaporation systems utilizing coil tubes for efficient heat transfer between successive effects.
  4. Process Vessel Internal Heat Exchangers: Immersion coils within storage tanks and process vessels for controlled heating or cooling of bulk fluids.
  5. Food & Pharmaceutical Processing: Sanitary-grade coil heat exchangers for pasteurization, sterilization, and thermal processing operations requiring CIP (Clean-in-Place) compatibility.
  6. Chemical Processing: Heat recovery systems in chemical synthesis, acid concentration, and solvent recovery operations requiring resistance to aggressive media.
  7. Oil & Gas Industry: Internal heat exchangers in separation vessels, scrubbers, and process heating/cooling systems.

Internal Heat Recovery System Design Considerations

The design and installation of internal heat recovery coils must account for:

  • Thermal expansion management: Accommodation of differential thermal expansion between the coil and vessel shell (allowable expansion per ASME Section VIII)
  • Flow distribution: Ensuring uniform fluid distribution across coil passes to prevent localized overheating or underutilization
  • Mechanical support: Proper coil anchoring and guide supports to prevent vibration-induced fatigue failure
  • Thermal stress analysis: Verification that peak thermal stresses remain within allowable limits under operating and transient conditions
  • Accessibility for maintenance: Design permitting inspection, cleaning, and replacement of individual coil sections without complete vessel decommissioning

Quality Certifications & Standards Compliance

Applicable International Standards

Quality Assurance Documentation

Manufacturer Quality System

Wenzhou Jixing Metal Materials Co., Ltd maintains a quality management system aligned with ISO 9001:2015 requirements, ensuring consistent product quality, process control, and customer satisfaction throughout the manufacturing lifecycle. Specialized manufacturing capabilities for internal heat recovery coils reflect deep technical expertise in coil forming, installation engineering, and thermal system design.

Unique Selling Points