ASME SA213 TP304L + AL1060 Finned Tube Bundle with 321 Header for H2S Service

ASME SA213 TP304L + AL1060 Finned Tube Bundle with 321 Header for H2S Service Air Coolers

Yuhong Group Co., Ltd. designs and fabricates finned tube bundles, replacement cores, and complete air-cooled heat exchanger (ACHE) assemblies under ASME U-Stamp certification, API 661, and TEMA standards. Our product range includes shell & tube heat exchangers, pressure vessels, air coolers, and critical components such as U-tubes, finned tubes, tubesheets, baffles, and channel heads. All products are manufactured with full material traceability and code-compliant documentation.

Product Overview

This finned tube bundle is purpose-built for air-cooled heat exchangers handling process streams containing hydrogen sulfide (H₂S). The bundle combines ASME SA213 TP304L seamless stainless steel tubes as the base carrier with AL1060 aluminum fins applied via mechanical finning technology. The header assembly is fabricated from 321 stainless steel to provide enhanced resistance to high-temperature sulfidation and stress corrosion cracking in sour environments.

The finned tube bundle is the core heat transfer element of any air cooler—ambient air is forced or induced across the bundle to remove heat from process fluid flowing inside the tubes. Extended surface fins multiply the heat transfer area by 5–10× compared to bare tubes while maintaining mechanical integrity at elevated operating temperatures.

Component Specifications

ASME SA213 TP304L Base Tube Properties:

• Tensile Strength: ≥ 485 MPa

• Yield Strength: ≥ 170 MPa

• Elongation: ≥ 35%

• Chemical composition: C ≤ 0.035%, Cr 18.0–20.0%, Ni 8.0–13.0%, Mn ≤ 2.00%, Si ≤ 1.00%, P ≤ 0.045%, S ≤ 0.030%

AL1060 Fin Properties:

• Thermal conductivity: ~237 W/m·K

• Maximum continuous operating temperature: 285°C (545°F)

• Tensile Strength: ≥ 90 MPa; Yield Strength: ≥ 35 MPa

321 Stainless Steel Header: The stabilized grade (Ti-stabilized) provides resistance to intergranular corrosion and sensitization during welding, making it suitable for high-temperature H₂S service where carbon steel would be susceptible to sulfide stress cracking.

Testing & Quality Assurance

All finned tube bundles undergo inspection and testing in accordance with ASME Code requirements and API 661 guidelines:

Application Scenarios

This finned tube bundle is specifically engineered for air-cooled heat exchangers in wet H₂S (sour) service, including:

• Refinery overhead condensers – naphtha hydrotreater (NHT) unit stripper column overhead air coolers

• Sour gas processing – amine unit air coolers and acid-gas cooling

• Hydrocracker and hydrotreater effluent air coolers

• Natural gas sweetening plants – H₂S-containing stream cooling

• Claus sulfur recovery units – tail gas cooling

For H₂S service, plug-type headers are preferred over cover-plate headers because they offer a more robust sealing mechanism and allow for easier inspection of tube ends—a common location for cracking in sour environments. Materials are selected with consideration for NACE MR0175/ISO 15156 requirements when H₂S partial pressure reaches or exceeds 0.05 psi.

Technical Advantages & Customization

Corrosion resistance: The ASME SA213 TP304L tube material provides resistance to sulfide stress corrosion cracking (SSCC) and general corrosion in wet H₂S environments. The 321 stainless steel header offers additional resistance to high-temperature sulfidation and eliminates sensitization concerns during fabrication.

Thermal performance: AL1060 aluminum fins deliver high thermal conductivity (~237 W/m·K), maximizing heat rejection per unit bundle area. The mechanical fin-to-tube bond ensures near-zero contact resistance, maintaining heat transfer efficiency throughout the bundle's service life.

Galvanic corrosion prevention: In H₂S service, aluminum fins (anodic) can preferentially corrode when in direct contact with stainless steel tubes (cathodic) if water condensation occurs. Our finning process applies fins over properly prepared tube surfaces with isolation measures to mitigate galvanic effects.

Customization options available:

• Tube OD and wall thickness per project thermal and mechanical requirements

• Fin type (L-type, LL-type, KL-type, G-type/embedded)

• Fin density (FPI) and fin height optimized for specific heat duty

• Header configuration (plug-type, cover-plate, or manifold)

• Bundle row count and tube layout per API 661

• ASME Section VIII Div. 1, TEMA, or API 661 design codes

Frequently Asked Questions

Q: Why specify 304L instead of 304 for H₂S service?
A: The "L" grade (low carbon, ≤ 0.035%) minimizes the risk of intergranular corrosion after welding—particularly important for tube-to-header joints in sour service where sensitization could create preferential attack paths.

Q: Why use a 321 stainless steel header with 304L tubes?
A: 321 (Ti-stabilized) stainless steel resists sensitization during header fabrication welding and provides enhanced resistance to high-temperature sulfidation. The combination allows the header to withstand the thermal and corrosive demands of the inlet/outlet zone while the 304L tubes handle the main heat transfer section.

Q: What is the maximum operating temperature for this bundle?
A: The AL1060 aluminum fins limit continuous service to 285°C (545°F). For applications exceeding this temperature, alternative fin materials or fin types should be considered.

Q: Are these bundles NACE MR0175/ISO 15156 compliant?
A: When specified, we can supply materials and fabrication in accordance with NACE MR0175/ISO 15156 for wet H₂S service, including hardness controls and post-weld heat treatment as required.

Q: What is the typical lead time for a custom finned tube bundle?
A: Standard fabrication timelines range from 30 to 150 days depending on bundle size, material availability, and testing requirements.

For technical specifications, drawings, or a quotation, please contact:
Email: vladimir@steelseamlesspipe.com