When purchasing explosion-proof electric heaters, choices such as "flameproof type," "increased safety type," and "pressurized type" must be evaluated based on specific operating conditions. Taking a chemical workshop Zone 1, Group IIB gas environment as an example, if the reactor thermal oil circulation system needs to raise the medium from ambient temperature to 280°C with temperature control accuracy within ±0.5°C, the design logic of the FBD-450 explosion-proof electric heater can serve as a reference for selection.
Ordinary electric heaters cannot be used in explosive gas atmospheres and must rely on isolation rooms or pressurized ventilation rooms, resulting in high civil construction and ventilation costs, long heat transfer paths, and significant heat loss. Indirect steam heating solutions are constrained by the distance to the boiler room and fluctuations in steam pressure, making it difficult to precisely adjust the heating rate. The FBD-450 adopts a flameproof structure with explosion-proof marking Ex d IIB T4 Gb, and can be installed directly in Zone 1 and Zone 2 hazardous locations without the need for an additional isolation room. It has an IP66 protection rating and withstands pressures up to 20 MPa, making it suitable for offshore platforms, chemical plants, and other occasions with space and corrosion resistance requirements.
This model is suitable for two types of scenarios: pipeline gas heating and thermal oil circulation heating. For pipeline gas heating, the gas can be heated from its initial temperature to the design temperature, with a design operating temperature of up to 720°C. For thermal oil heating, the thermal efficiency is close to 100%, with the vast majority of the heat generated by electricity transferred to the medium. During selection, the following must be confirmed: the explosive gas atmosphere zone (Zone 1 or Zone 2), gas group (IIA, IIB, or IIC), temperature class (T1–T4), and ensure that the complete unit has obtained an explosion-proof certificate and complies with the GB 3836 series of standards.
When requesting quotations from suppliers, it is recommended to require the explosion-proof certificate number and validity period for the complete unit, and confirm that the explosion-proof rating matches the on-site zone. At the same time, verify the temperature control method (whether it supports fully automatic DCS system temperature control and whether the accuracy meets the ±0.2°C to ±0.5°C requirement), whether it has over-temperature protection, low liquid level/dry-burn protection, and pressure/flow interlock control. For operating conditions with heating temperatures exceeding 700°C, the heating element material and insulation scheme must be confirmed. Some products are certified by ATEX or IECEx and can be used in supporting projects with export certification requirements.
