Double Coil Tube Barrel Heat Exchanger — Stainless Steel Coil Tube (Coiltube) Product Technical Specification
1. Product Overview
The Double Coil Tube Barrel Heat Exchanger (双盘管桶式换热器) is a high-efficiency thermal exchange system engineered around a precision-wound stainless steel coil tube (Coiltube). Manufactured by Wenzhou Jixing Metal Materials Co., Ltd (Product No. 862), this product represents a sophisticated integration of coiled tubing geometry with barrel-type housing design, optimized for heat transfer applications requiring compact footprint, high thermal conductivity, and resistance to corrosive media.
The coil tube serves as the primary heat transfer element, utilizing a serpentine winding configuration that maximizes surface area within a confined cylindrical volume. This architecture enables efficient thermal exchange between the process fluid flowing through the coil and the ambient medium contained within the barrel shell. The double-coil configuration further enhances heat duty by incorporating two independent or interlinked coil circuits, allowing for parallel, series, or cross-flow thermal management strategies.
2. Material & Properties
2.1 Base Material Grades
- Austenitic Stainless Steel (奥氏体不锈钢): Grade 304 (UNS S30400) and Grade 316L (UNS S31603) are the primary material selections, offering superior corrosion resistance, weldability, and mechanical ductility for coil forming operations.
- Super-Austenitic Grades (超级奥氏体): Grade 904L (UNS N08904) and Alloy 2200 (UNS N08220) are available for extreme environments involving concentrated chlorides, sulfuric acid, or oxidizing acids.
- High-Nickel Alloys (高镍合金): Hastelloy C-276 (UNS N10276) and Inconel 625 (UNS N06625) are offered for applications demanding exceptional resistance to reducing acids and high-temperature creep.
2.2 Key Mechanical and Physical Properties
| Property | Grade 304 | Grade 316L | Grade 904L | Unit |
|---|---|---|---|---|
| Tensile Strength (抗拉强度) | ≥ 515 | ≥ 485 | ≥ 550 | MPa |
| Yield Strength (屈服强度) | ≥ 205 | ≥ 170 | ≥ 275 | MPa |
| Elongation (延伸率) | ≥ 40 | ≥ 45 | ≥ 35 | % |
| Density (密度) | 7.93 | 8.00 | 8.08 | g/cm³ |
| Thermal Conductivity (导热系数) at 20°C | 16.3 | 14.6 | 11.4 | W/(m·K) |
| Thermal Expansion Coefficient (热膨胀系数) 20–100°C | 17.3 | 16.0 | 13.5 | ×10⁻⁶/K |
| Maximum Service Temperature (最高使用温度) | 870 | 870 | 1100 | °C |
2.3 Chemical Composition (Typical, wt%)
| Grade | C | Cr | Ni | Mo | N | Si | Mn |
|---|---|---|---|---|---|---|---|
| 304 | ≤0.08 | 18.0–20.0 | 8.0–10.5 | — | — | ≤0.75 | ≤2.0 |
| 316L | ≤0.03 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — | ≤0.75 | ≤2.0 |
| 904L | ≤0.02 | 19.0–23.0 | 23.0–27.0 | 4.0–5.0 | ≤0.20 | ≤0.50 | ≤1.00 |
3. Specifications
3.1 Coil Tube Dimensions
| Parameter | Specification Range | Standard Reference |
|---|---|---|
| Outer Diameter (外径) | Φ6.0 mm – Φ50.8 mm | ASTM A213 / GB/T 12771 |
| Wall Thickness (壁厚) | 0.5 mm – 3.0 mm | ASTM A269 / EN 10217 |
| Coil Winding Diameter (盘管卷制直径) | Φ100 mm – Φ600 mm | Custom per design |
| Coil Turn Spacing (圈间距) | 15 mm – 80 mm (adjustable) | Per thermal design calculation |
| Coil Length (盘管总长) | 5 m – 500 m (per assembly) | Custom per design |
| Surface Finish (表面光洁度) | Ra ≤ 0.8 μm (Industrial); Ra ≤ 0.4 μm (Sanitary) | ASTM A270 / GB/T 8898 |
| End Connection (端部连接) | Flange (法兰), Threaded (螺纹), Welded (焊接), Tri-Clamp (卡箍) | ASME B16.5 / GB/T 9119 |
3.2 Barrel Heat Exchanger Housing
| Parameter | Specification |
|---|---|
| Housing Material (壳体材质) | Carbon Steel (碳钢) / Stainless Steel (不锈钢) / Alloy Steel (合金钢) |
| Housing Diameter (壳体直径) | Φ300 mm – Φ2000 mm |
| Housing Length (壳体长度) | 500 mm – 6000 mm |
| Design Pressure (设计压力) | 0.6 MPa – 6.4 MPa |
| Design Temperature (设计温度) | −20°C to 350°C |
| Heat Duty (换热负荷) | 50 kW – 2000 kW |
| Pressure Rating (压力等级) | PN6 – PN64 (EN 12261) |
| Insulation (保温层) | Rockwool (岩棉) / Aerogel (气凝胶) / Glass Wool (玻璃棉), 25–100 mm |
3.3 Performance Parameters
| Parameter | Typical Value |
|---|---|
| Overall Heat Transfer Coefficient (总传热系数 U) | 800 – 2500 W/(m²·K) |
| Thermal Efficiency (热效率) | ≥ 92% |
| Pressure Drop (压降) | ≤ 0.15 MPa (at design flow rate) |
| Approach Temperature (端差温度) | ≥ 5°C |
| Service Life (使用寿命) | ≥ 15 years (under normal operating conditions) |
4. Manufacturing Process
4.1 Coil Tube Fabrication
- Raw Material Inspection (原材料检验): Incoming stainless steel seamless tubes undergo spectrographic analysis (光谱分析) for chemical composition verification, ultrasonic testing (超声检测, UT) for internal defects, and hydrostatic testing (水压试验) for wall integrity per ASTM A315.
- Cold Drawing & Sizing (冷拔与定径): Tubes are cold-drawn to precise dimensional tolerances (±0.05 mm for OD, ±0.02 mm for wall thickness) using multi-pass drawing dies. This process enhances mechanical properties through strain hardening while maintaining surface integrity.
- Coil Winding (盘管卷制): Using CNC-controlled bending machines (数控弯管机), tubes are wound into the specified helical geometry with controlled bending radius (R ≥ 3D for seamless grades, R ≥ 6D for sanitary applications) to prevent wall thinning, ovality, or wrinkling. Bending speed is regulated to minimize residual stress accumulation.
- Welding & Forming (焊接与成形): Inlet/outlet nozzles, support saddles, and connection fittings are welded to the coil using TIG (Tungsten Inert Gas, 钨极氩弧焊) or orbital welding (轨道焊) techniques. Post-weld heat treatment (焊后热处理) is performed where required to relieve residual stresses and restore corrosion resistance.
- Surface Treatment (表面处理): Pickling (酸洗) and passivation (钝化) are performed using citric acid or nitric acid solutions to remove oxide scale and form a protective chromium oxide film. Electropolishing (电解抛光) is available for sanitary-grade applications requiring Ra ≤ 0.4 μm.
4.2 Barrel Assembly
- Shell Fabrication (壳体制造): The barrel housing is fabricated from rolled steel plates or seamless pipe sections, with circumferential and longitudinal welds inspected by radiographic testing (射线检测, RT) or phased array ultrasonic testing (相控阵超声检测, PAUT) per ASME Section V.
- Coil Installation (盘管安装): The wound coil assembly is inserted into the barrel housing with appropriate thermal expansion allowances. Spring-loaded or bellows-type expansion joints (膨胀节) are incorporated at connection points to accommodate differential thermal expansion between the coil and shell.
- Insulation & Cladding (保温与外覆): Multi-layer thermal insulation is applied to minimize heat loss, followed by stainless steel or aluminum outer cladding for mechanical protection and aesthetic finish.
- Pressure Testing (压力试验): Hydrostatic pressure testing (水压试验) is conducted at 1.5× design pressure for 30 minutes, with pneumatic testing (气密试验) at 1.1× design pressure for leak-tightness verification.
- Final Inspection (最终检验): Dimensional verification, surface roughness measurement, and non-destructive testing (无损检测, NDT) are performed prior to packaging and dispatch.
5. Applications
5.1 Industrial Thermal Processing
- Chemical Processing (化工处理): Heating and cooling of process fluids including acids, alkalis, solvents, and reactive chemicals in continuous production lines. The double-coil configuration enables precise temperature control for exothermic and endothermic reactions.
- Petrochemical Industry (石化行业): Preheating of feedstocks, condensation of overhead vapors, and heat recovery in distillation columns. Grade 316L and 904L coils resist sulfur compound corrosion.
- Pharmaceutical Manufacturing (制药制造): Sanitary-grade coil tubes (Ra ≤ 0.4 μm, electropolished) for CIP (Clean-In-Place) and SIP (Sterilization-In-Place) compatible heating and cooling of pharmaceutical solutions, ensuring no dead-leg contamination zones.
- Food & Beverage Processing (食品饮料加工): Pasteurization, sterilization, and rapid cooling of liquid food products including dairy, juice, and beer. Compliant with 3-A Sanitary Standards and FDA 21 CFR requirements.
5.2 Energy & Environmental
- Waste Heat Recovery (余热回收): Capturing low-grade thermal energy from exhaust gases or process effluents to preheat incoming feedwater or combustion air, improving overall system thermal efficiency.
- Geothermal Heat Exchange (地热换热): Utilizing stainless steel coil tubes in geothermal well heat exchangers for direct-use heating applications, leveraging the material's resistance to geothermal brine corrosion.
- Solar Thermal Systems (太阳能热系统): Integration with solar thermal collectors for concentrated solar power (CSP) applications and industrial process heat generation.
5.3 Marine & Offshore
- Marine Heat Exchangers (船用换热器): Engine cooling, lubricating oil cooling, and exhaust gas heat recovery in marine propulsion systems. Duplex stainless steel (双相不锈钢, e.g., 2205) coils provide resistance to seawater pitting and crevice corrosion.
- Offshore Platform Utilities (海上平台公用工程): Hot water generation, fuel heating, and process fluid conditioning in offshore oil and gas production facilities.
6. Quality Certifications & Standards Compliance
6.1 Applicable Standards
| Standard | Description | Scope |
|---|---|---|
| ASTM A213 | Standard Specification for Seamless Austenitic Stainless Steel Tubes for High-temperature Service | Coil tube material |
| ASTM A269 | Standard Specification for Austenitic Stainless |