Product Description
Engineered and produced in our high-alloy foundry and machining facilities in Jingjiang, our Ethylene Cracker Radiant Coil is a premium, centrifugally cast pyrolysis coil assembly designed to operate under severe thermal conditions inside industrial ethylene cracking furnaces. Drawing upon our 26 years of specialized high-temperature metallurgical manufacturing experience and certified under ASME "U" and "S" standards, we manufacture each Ethylene Cracker Radiant Coil using advanced high-nickel alloy steels such as 35Cr45NiNb and 25Cr35NiNb that withstand metal temperatures up to 1,150°C. Featuring full-length precision pull-boring and automated orbital welding, this high-integrity Ethylene Cracker Radiant Coil delivers superior resistance to high-temperature carburization, thermal shock, and creep rupture, providing global ethylene producers and EPC contractors with a durable coil system that maximizes olefin selectivity while extending decoking run-lengths.
Applications
Naphtha & Gas Cracking Furnaces: Serving as radiant pyrolysis coils in world-scale ethylene plants cracking naphtha, ethane, propane, and butane.
Short-Residence-Time Cracking Units: Operating in high-severity cracking configurations requiring rapid heat transfer and high radiant heat fluxes.
Furnace Radiant Section Revamps: Replacing conventional cracking coils with high-grade micro-alloyed coils to expand production throughput and reduce decoking frequency.
Severe-Service Pyrolysis Systems: Providing specialized replacement coils for furnaces processing heavy gas oils (AGO/HVGO) where carburization and coking risks are elevated.
Technical Specifications
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Manufacturing Standards |
ASME Section VIII Div. 1, ASME B31.3, ASTM A608, API 530, DIN 17465 |
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Casting & Fabrication Process |
Horizontal centrifugal casting, full-length pull-boring, and automated precision orbital welding |
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Material Chemistry (35Cr45NiNb) |
Cr: 34.0% – 37.0%, Ni: 43.0% – 48.0%, Nb: 0.8% – 1.8%, with balanced micro-alloying additions |
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Alternative Material Grades |
25Cr35NiNb + Micro, HP40Nb, 20Cr32NiNb |
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Mechanical Properties (Room Temp) |
Tensile strength Rm ≥ 450 MPa; Yield strength Rp0.2 ≥ 240 MPa; Elongation A5 ≥ 8.0% |
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Operating Temperatures |
Continuous tube metal design temperature from 1,100°C to 1,150°C; Process gas outlet temperature up to 880°C |
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Creep Rupture Strength |
Average rupture stress for 35Cr45NiNb exceeding 17.5 MPa at 1,000°C (10,000 hours) and 11.0 MPa at 1,000°C (100,000 hours) |
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Internal Surface Finish |
Precision pull-bored to an internal surface roughness of Ra ≤ 3.2 µm (optional rifled / dimpled inner profiles) |
Customization Capabilities
Diverse Coil Geometries: Fabricating single-pass straight tubes, 2-pass U-coils, 4-pass W-coils, and split-pass (2-into-1 or 4-into-1) high-selectivity coil configurations.
Matched Cast Fittings & Spools: In-house production of centrifugally cast and static-cast return bends, Y-pieces, weldolets, and transition cones matched in metallurgy and wall thickness.
Surface Profiling for Enhanced Heat Transfer: Offering internal micro-fin profiling or rifled inner tube geometries that enhance gas turbulence, improve heat transfer rates, and suppress coke deposition.
Modular Pre-Fabricated Harp Shipping: Pre-assembling multiple coil passes into rigid harp structures with alignment spacers and support attachments to minimize field welding.
Zero MOQ Flexibility: Supplying single replacement coil assemblies for emergency turnaround repairs as well as complete multi-furnace retubing packages.
Quality Control
Certified Quality Standards: Certified under ASME "U" and "S" stamps, ISO 9001:2015, and ISO 3834-2 International Welding Quality System.
Full QR Code Traceability: Every cast tube section, return bend, and weld seam carries an individual QR code linked to certified chemical analyses, heat numbers, and inspection reports.
Comprehensive Non-Destructive Testing: 100% Radiographic Testing (RT) on all circumferential butt welds, 100% Liquid Penetrant Testing (PT) on machined surfaces, and 100% Positive Material Identification (PMI).
Accelerated Creep Rupture Testing: Performing high-temperature tensile and creep rupture testing on representative casting coupons to verify compliance with Larson-Miller master curves.
Protective Heavy Export Packaging: Packed in heavy-duty structural steel transport frames with custom polyurethane cushioning, moisture barrier wrapping, and end caps to prevent contamination during ocean freight.
FAQ
Q: What advantages does 35Cr45NiNb offer over conventional 25Cr35Ni alloy for ethylene cracking?
A: 35Cr45NiNb provides a significant increase in chromium (34-37%) and nickel (43-48%) content, increasing allowable tube metal temperatures from 1,080°C to 1,150°C. This allows higher cracking severity, improves resistance to high-temperature carburization, and extends tube operating life.
Q: What is the typical production lead time for a set of cracking coils?
A: A full replacement coil package typically requires 4 to 6 months from drawing sign-off and casting schedule confirmation to final delivery. Emergency replacement spools can often be supplied within 3 months.
Q: What warranty coverage do you provide for overseas deliveries?
A: We provide an 18-month warranty from site arrival or 12 months from commercial operation (whichever comes first), backed by complete technical documentation and welding procedure specifications (WPS).
Q: What payment terms and currencies do you accept for export contracts?
A: We support EXW and FOB shipping terms. Our standard commercial milestones are 30% advance deposit, 40% manufacturing milestone payment, and 30% balance prior to factory dispatch, payable in USD, EUR, or RMB.
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