Explosion-Proof Electric Heaters
Explosion-proof electric heaters are core heating equipment for flammable and explosive environments in chemical, petroleum, natural gas, marine, and mining industries (such as Zone 1, Zone 2, and Class IIA, IIB locations). They convert electrical energy into thermal energy to heat, maintain, or raise the temperature of liquid, gaseous, or solid media. The maximum operating temperature can reach 720°C, thermal efficiency approaches 100%, and they support DCS systems for fully automatic temperature control.
Combined with the latest 2026 industry standards and selection logic, here is a practical procurement guide for you:
I. Core Selection Logic: First Determine Explosion-Proof Grade, Then Determine Structural Form
1. Explosion-Proof Compliance — The First Red Line in Selection
According to GB 3836.15-2024 and GB 50058-2014 standards, selection must match the on-site hazardous area:
Hazardous Area Permitted Explosion-Proof Type Typical Application
Zone 0 (explosive gas continuously present) Only Ex ia intrinsically safe, Ex ma encapsulated Rarely used for heaters
Zone 1 (may occur during normal operation) Ex d flameproof, Ex e increased safety, Ex ib intrinsic safety Reactors, storage tank heat tracing
Zone 2 (occasionally occurs under abnormal conditions) All of the above + Ex nA non-sparking Pipeline preheating, factory heating
Gas Group and Temperature Class:
Group: IIA < IIB < IIC (IIC covers IIB and IIA; hydrogen or acetylene requires IIC)
Temperature Class: T1 (max 450°C) > T2 > T3 > T4 > T5 > T6 (max 85°C). The maximum surface temperature of the equipment must be lower than the auto-ignition temperature of the medium.
Pitfall Alert: Must verify the complete explosion-proof certificate (CNEX/NEPSI, etc.), not just the certificate cover; export projects must comply with IECEx or ATEX standards.
2. Structural Form — Select by Medium and Installation Method
Structural Type Applicable Medium Typical Scenario Advantages
Flanged immersion type Thermal oil, water, oil Reactors, storage tanks, oil tanks Simple installation, high power density
Pipeline circulation type Flowing gas, liquid media Natural gas pipeline preheating, process fluid heating High thermal efficiency, no dead zones
Air duct type Air, nitrogen Factory heating, waste gas treatment, drying rooms Large heat exchange area, low air resistance
Molten salt type Nitrate, chloride salts Solar thermal storage, high-temperature processes Withstands 500-800°C high temperatures
Flexible heating jacket/track type Irregular equipment, pipe welds On-site heat treatment, valve heat tracing Flexible installation, no shutdown or disassembly required
II. Key Parameters: 5 Hard Indicators That Must Be Verified
1. Power Calculation and Surface Load
Power calculation: Must consider specific heat capacity, density, flow rate, and temperature rise of the medium; reserve 10%-20% margin in engineering. Liquid heating formula: P=3600×η×c×ρ×Q×ΔT (η immersion type ≈0.95, pipeline type ≈0.9)
Surface power load: General range for tubular heaters is 10~100 W/cm²; <v>**<v>For media prone to carbon deposition such as thermal oil, it must be controlled at ≤0.7~2.0 W/cm²** to avoid local overheating and coking
2. Material Adaptation
Liquid heating: For corrosive media, choose titanium tubes or S32168 high-temperature alloy; for ordinary water/oil, choose 304 stainless steel
Gas heating: Optimize surface load, match air velocity design
Molten salt/high temperature: High nickel-based alloy (Inconel 600/625) or special stainless steel
Insulation material: Ordinary polyimide in pH<2 or >12 environments has insulation resistance drop by more than 50% within three months; FEP coating is recommended for strongly corrosive environments
3. Temperature Control Accuracy and Protection
Temperature control accuracy: Conventional ±1~2°C, high-end PID intelligent temperature control can reach ±0.2~0.5°C
Essential protection: Over-temperature protection, low liquid level/dry burn protection, overload protection, phase loss protection, pressure/flow interlock
4. Protection Rating and Environmental Adaptability
Outdoor or humid areas: IP65 and above
Coastal or washdown scenarios: IP66
Short-term immersion areas: IP67/IP68
5. Voltage and Communication
Voltage: 220V/380V conventional, high power can choose 690V or 6kV
Communication: Supports Modbus, RS485, can connect to PLC/DCS systems
III. Mainstream Brands and Manufacturer Recommendations
International First-Tier Brands
Brand Representative Series Core Advantages Applicable Scenarios
Eaton Crouse-Hinds EXH Series UL/CSA certified, NEMA 7/9 protection, suitable for North American standard projects Multinational petrochemical, offshore platforms
Backer HTS (Sweden) — 60 factories worldwide, full range of heating tubes/films/belts High-end industrial, export projects
Watlow (USA) — Founded in 1920, integrated temperature control system + heater Semiconductor, medical equipment
Domestic High-Quality Brands
Brand Location Core Advantages Applicable Scenarios
Dongfang Electric Heating Zhenjiang Listed company, 10KV high-voltage direct connection technology, ATEX explosion-proof certification, industry standard drafting unit New energy, petrochemical high-end explosion-proof
Zhenjiang Thermal efficiency 98%+, Jiangsu Province first-set major equipment, serves military/marine/Sinopec Petrochemical reactors, molten salt heating
Jiangsu Zhongzhong Electric Heating Zhenjiang Yangzhong Industry standard drafting unit, annual capacity of tens of thousands of units, full range of explosion-proof/molten salt/thermal oil Chemical, pharmaceutical
Yancheng Independent production across the entire industry chain, PID temperature control ±0.8°C, room temperature to 280°C in half an hour Thermal oil furnaces, air duct heating
Yancheng Specialized and sophisticated enterprise, fixed pressure vessel A2 qualification, CE/RoHS certification Pipeline type, cast aluminum/cast copper heaters
Zhenjiang High-tech enterprise, 27 patents, explosion-proof electric heaters + thermal oil furnaces + pressure vessels Chemical, new energy
Yangzhong Far-infrared heating technology, explosion-proof certificate/ISO/CCC certification, compatible with DCS/PLC Reactors, pipelines, hydrogen energy heating
Yangzhong Special explosion-proof/anti-corrosion/high-temperature resistant, 5-year maintenance-free customization, price 10%-15% lower than industry average High cost-performance bulk procurement
Yangzhou Local and Surrounding Manufacturers
Considering your location in Yangzhou, the following enterprises are worth noting:
Founded in 2008, conductors use 99.99% T2 copper, housing is integrally pultruded aluminum alloy profile, thermal efficiency 95%, failure rate below 0.4%, annual capacity over 700 units, applied in high-power heating scenarios in power and metallurgy.
Yangzhou Hengwei Electric Heating Technology Co., Ltd.: In addition to main electric heaters, also has supply capability for explosion-proof heating equipment, suitable for customers with comprehensive "heating + testing" procurement needs.
Zhenjiang/Yangzhong Industrial Belt (within 1 hour drive from Yangzhou): Zhenjiang Sanwei, Jiangsu Zhongzhong, Yangzhong Shenzhou/Hengda/Xinghuo, etc. Close geographical distance, convenient after-sales response, preferred area for Yangzhou users to purchase explosion-proof electric heaters.
IV. Scenario Selection Quick Reference
Petrochemical reactor/thermal oil furnace Flanged immersion type, Ex d IIB T4, surface load ≤2.0 W/cm², PID temperature control Zhenjiang Sanwei/Dongfang Electric Heating/Yancheng Hengneng
Natural gas pipeline preheating Pipeline circulation type, Ex d IIB T4, heat exchange area matched to flow rate design Jiangsu Pengxingbo/Yangzhong Shenzhou
Hydrogen/acetylene and other IIC high-risk environments Ex d IIC T6 flameproof China Nuclear Power Research and Design Institute Electric Heating Appliance Factory
Solar thermal storage/molten salt heating Molten salt type, Inconel alloy tubes, withstands 500-800°C Zhenjiang Sanwei/Jiangsu Zhongzhong
Factory heating/waste gas treatment Air duct type, IP65 protection, Ex d IIB T4 Shanghai Xionglei/Yancheng Hengneng
On-site heat treatment/irregular equipment Track type/flexible heating jacket, portable temperature control box Zhenjiang Dongfang Energy Saving/Wujiang Huali
High cost-performance bulk procurement Standard flanged/pipeline type, Ex d IIB T4 Yangzhong Hengda/Zhejiang Ketai (price 10%-20% lower)
V. Installation and Maintenance Key Points
Installation: Reliable grounding (grounding resistance ≤4Ω), install jumper wires at flange connections; heating tubes must extend at least 50mm below the medium to be heated, ensuring heating temperature is within control range
Strictly prohibit energizing without medium: Dry burning will instantly burn out the heating element
Regular maintenance: Check insulation resistance of heating elements (cold state ≥100 MΩ), sealing of explosion-proof joints, and fastener condition
Maintenance qualification: Only certified personnel are allowed to perform maintenance; replacement parts must match original factory explosion-proof parameters
