What are the small designs of thermal oil electric heater?

1. Design heat load. A certain margin should be left between the heat load and effective heat load of an electrically heated thermal oil boiler.
2. Design temperature. The design temperature of a thermal oil boiler is determined by its operating temperature and should be designed in accordance with the relevant provisions of GB9222, "Calculation of Strength of Water-Tube Boiler Components."
3. Design pressure. The design pressure of the thermal oil should be slightly higher than the operating pressure and should not be less than the opening pressure of the safety valve. The design pressure of a gas-phase furnace should be 1.2 to 1.5 times the operating pressure; the design pressure of a liquid-phase furnace should be 1.05 to 1.2 times the pressure. The pressure difference between the inlet and outlet of the thermal oil in a liquid-phase furnace should be greater than 0.15 MPa (1.5 kgf/cm²).
4. Thermal oil inlet and outlet temperature. The design should be economical and safe, ensuring an appropriate temperature difference within the system for the thermal oil to operate. This temperature difference should be less than 30°C.
5. Flow rate of the thermal oil in the pipe. To maintain a constant flow rate within the heat transfer oil pipes without causing local overheating and coking, a typical flow rate of 2-4 m/s is used for the radiant section, and 1.5-2.5 m/s is used for the convection section. When determining these parameters, the resistance of the hot oil within the pipes and the need to maintain turbulent flow should also be considered. Larger pipe diameters increase the flow rate, while smaller pipe diameters require lower flow rates.
6. Average thermal intensity of the furnace tubes. The design requires the average thermal intensity of the furnace tubes to be within a certain range to prevent overheating of the heat transfer oil and to fully utilize the heat transfer area of the furnace tubes. The average thermal intensity of the radiant section is generally 0.084-0.167 GJ/(m²·h), and for the six-section section, it is 0.033-0.047 GJ/(m²·h).
7. Exhaust gas temperature. Depending on the operating temperature of the thermal oil, the difference between the exhaust gas temperature and the oil temperature should be controlled between 80 and 120°C, with the exhaust gas temperature preferably between 350 and 400°C to minimize the convective heating surface. To fully utilize the heat energy, waste heat recovery equipment should be installed to recycle the higher exhaust gas temperatures removed by the thermal oil boiler. This is particularly important for larger thermal oil boilers.
8. All pipes and accessories in contact with the thermal oil must not be made of non-ferrous metals or cast iron. Flanges and valves must be cast steel valves with a nominal pressure of 2.5 MPa (approximately 25 kgf/cm²) or higher. Seals must be made of high-temperature and oil-resistant materials. When using biphenyl mixture-based thermal oil, tongue-and-groove or convex-and-concave flanges should be used for connections.
9. The thermal oil boiler must be equipped with a low-level drain valve that can completely drain the material, ensuring no residual liquid remains.