High-Acid-Sulfur Resistant Stainless Steel Coil Tube for Wet Natural Gas Heating Furnaces
Product Overview
The Coil Tube (盘管) produced by Wenzhou Jixing Metal Materials Co., Ltd. (温州吉兴金属材料有限公司) is a specialized stainless steel tubular product engineered for the most demanding environments in the oil and gas industry — specifically, high-acid-sulfur wet natural gas processing facilities. These coil tubes serve as critical heat-exchange and process-transfer components within heating furnaces (加热炉), where they are subjected to extreme thermal cycling, aggressive sulfide corrosion, and high-pressure wet gas streams.
Based on extensive research into the corrosion behavior of heating furnace coil tubes in high-acid-sulfur wet natural gas environments (高含硫酸性湿天然气), this product line incorporates advanced metallurgical formulations and manufacturing processes to achieve superior resistance against sulfide stress cracking (Sulfide Stress Cracking, SSC), chloride-induced pitting corrosion, and thermal fatigue failure. The coil tube design eliminates the need for butt-welded joints along the length of the tube run, significantly reducing potential failure points in high-risk service conditions.
Material & Properties
The coil tubes are manufactured from high-performance austenitic and duplex stainless steel grades, selected specifically for their resistance to the synergistic degradation mechanisms present in high-acid-sulfur wet natural gas service. The primary material grades include:
- Super Austenitic Stainless Steels (超奥氏体不锈钢): Grades such as Alloy 20 (UNS N08020), C-276 (UNS N10276), and S31803 duplex variants, offering exceptional resistance to sulfide corrosion and chloride pitting.
- High-Nickel Alloy Steels (高镍合金钢): Ni-Base alloy compositions with elevated chromium (Cr ≥ 20%) and molybdenum (Mo ≥ 3%) content for enhanced pitting resistance equivalent number (Pitting Resistance Equivalent Number, PREN ≥ 40).
- Duplex Stainless Steels (双相不锈钢): Super duplex grades (e.g., UNS S32750/S32760) combining high yield strength (≥ 550 MPa) with outstanding resistance to sulfide-induced cracking.
Key Mechanical Properties:
- Tensile Strength (抗拉强度): ≥ 550 MPa (minimum, depending on grade)
- Yield Strength (屈服强度): ≥ 275 MPa (0.2% offset)
- Elongation at Fracture (断裂伸长率): ≥ 35%
- Impact Toughness (冲击韧性): ≥ 34 J at -40°C (Charpy V-Notch)
Corrosion Resistance Characteristics:
- Pitting Resistance (点蚀抗力): PREN ≥ 40 (Cr + 3.3 × Mo + 16 × N)
- Sulfide Stress Cracking Resistance (硫化物应力开裂抗力): Passes NACE MR0175/ISO 15156 compliance testing
- Intergranular Corrosion Resistance (晶间腐蚀抗力): Passes ASTM A262 Practice 1E (66-hour, 65% HNO₃ test)
- Thermal Cycling Fatigue Life (热循环疲劳寿命): > 10,000 cycles at ΔT = 400°C
Specifications
| Parameter (参数) | Specification (规格) | Standard / Reference (标准/参考) |
|---|---|---|
| Outer Diameter (外径) | Φ19.05 mm – Φ76.20 mm (3/4" – 3") | ASTM A213 / ASTM B407 |
| Wall Thickness (壁厚) | 1.00 mm – 6.35 mm (0.040" – 0.250") | ASTM A213 / ASME SA-213 |
| Minimum Bend Radius (最小弯曲半径) | ≥ 5D (5 times outer diameter) | Internal design standard |
| Coil Length (盘管长度) | 10 m – 300 m (continuous, seamless) | Manufacturer specification |
| Maximum Operating Temperature (最高使用温度) | ≤ 450°C (depending on grade) | ASTM A213 |
| Maximum Operating Pressure (最高工作压力) | ≤ 15.0 MPa (design dependent) | ASME B31.3 |
| Surface Finish (表面光洁度) | Ra ≤ 0.4 μm (electropolished available) | ASTM A967 |
| Chemical Composition Control (化学成分控制) | ±0.10% on Cr, Ni, Mo; ±0.02% on S, P | ASTM A213 / ISO 3506 |
| Heat Treatment (热处理) | Solution Annealing 1050°C – 1150°C + Water Quench | ASTM A213 |
| Non-Destructive Testing (无损检测) | 100% Eddy Current (涡流检测) + Hydrostatic Test (水压试验) | ASTM A269 / ASME SA-213 |
| Corrosion Testing (腐蚀测试) | H₂S partial pressure up to 100% (pure H₂S service) | NACE MR0175 / ISO 15156 |
Manufacturing Process
The production of high-acid-sulfur resistant coil tubes follows a rigorous multi-stage manufacturing protocol to ensure metallurgical integrity and dimensional precision:
- Vacuum Induction Melting (真空感应熔炼, VIM): Raw alloy stock is melted under ultra-high vacuum (≤ 10⁻³ Pa) to minimize oxygen and nitrogen pickup, ensuring tight control over trace element content (S ≤ 0.005%, P ≤ 0.020%).
- Arc Casting or Electroslag Remelting (电弧浇注/电渣重熔, AOD/ESR): Secondary refining to achieve homogenized microstructure and eliminate segregation of chromium and molybdenum, critical for uniform corrosion resistance throughout the tube wall thickness.
- Hot Rolling and Cold Drawing (热轧与冷拔): Billet is hot-rolled to near-final dimensions, followed by multi-pass cold drawing to achieve precise wall thickness tolerance (±0.05 mm) and enhanced grain orientation for improved fatigue performance.
- Tube Piercing and Seamless Forming (穿孔与无缝成型): The tube is formed without weld seams using rotary piercing (曼内斯曼穿孔法) or capillary piercing techniques, producing a continuous, joint-free tube body essential for eliminating stress-corrosion initiation sites.
- Coil Bending and Forming (盘管弯曲成型): Cold bending is performed at controlled strain rates (≤ 0.002 s⁻¹) with in-line induction heating to prevent work-hardening and maintain ductility. The bending process is monitored via real-time strain sensors to ensure uniform plastic deformation.
- Solution Annealing (固溶处理): Post-forming heat treatment at 1050°C – 1150°C followed by rapid water quenching to dissolve any carbide precipitation (particularly Cr₂₃C₆) and restore full solid-solution strengthening, ensuring maximum pitting and intergranular corrosion resistance.
- Non-Destructive Examination (无损检测): 100% eddy current testing (涡流检测) for internal and external surface defects, supplemented by ultrasonic testing (超声波检测, UT) for wall thickness verification and hydrostatic testing (水压试验) at 1.5× design pressure for leak integrity.
- Surface Treatment (表面处理): Optional electropolishing (电解抛光) to Ra ≤ 0.4 μm for enhanced corrosion resistance and ease of cleaning, or passivation treatment per ASTM A967 for maximum passive film stability.
Applications
This coil tube product is specifically designed for the following high-severity service environments:
- High-Acid-Sulfur Wet Natural Gas Processing (高含硫酸性湿天然气处理): Primary application in gas dehydration units, acid gas injection systems, and amine regeneration columns where H₂S partial pressures exceed 50% and free water is continuously present.
- Heating Furnace Tube Bundles (加热炉炉管束): Radiant sections of fired heaters in refinery and petrochemical plants processing sour crude oil or wet gas feeds with total sulfide content > 2.0 wt%.
- Hydrogen Sulfide Recovery Units (硫化氢回收装置): Claus process reactors and acid gas compressors in natural gas sweetening facilities (天然气脱硫装置).
- Oil Refinery Sour Water Systems (炼厂含硫污水系统): High-temperature sour water strippers and reflux drums operating under reducing, sulfidic conditions.
- Subsea Production Systems (海底生产系统): Deepwater flow lines and process piping in high-pressure, high-temperature (HPHT) sour reservoir environments.
- Chemical Reactor Cooling Loops (化学反应器冷却回路): Heat exchange coils in reactors processing chlorinated or sulfidic chemical intermediates.
Quality Certifications & Standards Compliance
All coil tube products manufactured by Wenzhou Jixing Metal Materials Co., Ltd. are produced under a certified quality management system and conform to the following international standards and certifications:
- Quality Management System (质量管理体系): ISO 9001:2015 certified manufacturing
- Pressure Equipment (压力设备): PED 2014/68/EU (Pressure Equipment Directive) compliant; ASME "U" Stamp and "S" Stamp authorization
- Oil & Gas Service (油气服务): NACE MR0175/ISO 15156 (Materials for Use in H₂S-Containing Environments in Oil and Gas Production)
- Material Standards (材料标准): ASTM A213/A213M (Austenitic and Ferritic/Austenitic Stainless Steel Tubing); ASTM B407 (Nickel-Copper-Chromium-Molybdenum Alloy Tubing); ASME SA-213
- Testing Standards (测试标准): ASTM A262 (Corrosion Resistance of Stainless Steels); ASTM A967 (Chemical Passivation); ASTM E709 (Eddy Current Testing)
- Third-Party Inspection (第三方检验): Available upon request (e.g., TUV, Lloyd's Register, DNV, Bureau Veritas)
- Environmental Management (环境管理): ISO 14001:2015 certified
- Product Traceability (产品追溯性): Full heat-number traceability from melt to finished coil; material test reports (MTR) provided per EN 10204 Type 3.1
Unique Selling Points
The coil tube products from Wenzhou Jixing Metal Materials Co., Ltd. offer several distinctive advantages over conventional welded or butt-jointed tubing solutions for high-acid-sulfur wet natural gas service:
- Seamless Continuous Construction (无缝连续结构): The coil tube design eliminates longitudinal weld seams entirely, removing the most vulnerable corrosion initiation sites identified in field failure analyses of high-acid-sulfur environments.
- Research-Validated Corrosion Performance (研究验证的腐蚀性能): Product specifications are informed by dedicated research into corrosion mechanisms of heating furnace coil tubes in high-acid-sulfur wet natural gas (高含硫酸性湿天然气加热炉盘管腐蚀规律), providing data-driven material selection and design optimization.
- Superior Thermal Fatigue Resistance (优异热疲劳抗力): Cold-formed coil geometry with controlled strain distribution provides > 10,000 thermal cycling life, far exceeding the typical 3,000–5,000 cycles of conventional butt-welded tube assemblies.
- Customizable Coil Geometry (可定制盘管几何形状): Flexible manufacturing capability allows custom coil diameters, pitch configurations, and total lengths to optimize heat transfer efficiency and pressure drop for specific furnace designs.
- Extended Service Life (延长使用寿命): Field performance data indicates 3–5× longer service intervals compared to standard 316L coil tubes in equivalent high-acid-sulfur service, resulting in significant reduction in unplanned shutdowns and maintenance costs.
- Full Traceability and Documentation (完整追溯性与文档): Each coil is accompanied by comprehensive material test reports, NDE records, and corrosion test certificates enabling seamless integration into owner-engineered quality assurance programs.
Technical Support & Consultation
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including:
- Material selection engineering based on specific H₂S partial pressure, temperature, and flow regime conditions
- Corrosion rate prediction modeling for project-specific service environments
- Coil layout and stress analysis optimization for heating furnace applications
- Post-installation monitoring program design for remaining life assessment
Note: All specifications are subject to confirmation based on the specific grade, dimensions, and service conditions required. Custom material formulations and non-standard geometries are available upon engineering consultation. For detailed product data sheets and corrosion performance test reports, please contact the manufacturer's technical department directly.