In the event of a flow interruption, if the temperature control of the cold hydrogenation electric heater is governed by the outlet temperature, the sensor signal cannot provide an accurate signal, resulting in continuous heating requests. As a result, the electric heater becomes increasingly hot. If an over-temperature sensor is functioning, it can still shut off the power source. However, if the over-temperature sensor fails to operate, either the electric heating element may burn out or the container may crack and melt. In either case, in an explosion-proof environment, unforeseen consequences may arise.
If the sensor is positioned closely to a circuit of an electric heater that does not heat, while other circuits are, the over-temperature sensor cannot detect the correct temperature or is delayed by several degrees. When multiple electric heaters are used together on the same skid, the wires may be incorrectly connected and crossed. Many heat exchanger manufacturers have invested a great deal of research into the cracking of tubes in shell-and-tube heat exchangers, but there are few papers on the cracking of electric heater components, as it is believed that the internal components of electric heating elements are filled with solid magnesium oxide powder, which can be ejected into the wiring cavity under high-pressure conditions, causing electrical leakage.
Magnesium oxide powder at high temperatures is an excellent thermal conductor and insulator. However, the powder is prone to absorb moisture, which can reduce electrical insulation. The cause of absorption is mainly due to ambient humidity, prolonged storage, or excessively long periods of opening the lid for wiring, etc. If power is applied and the circuit breaker fails to disconnect in time, it may cause the heating element to be pierced.
The electric tracing heater is composed of conductive polymers, two parallel metal conductors, and an insulating sheath. Its features include the conductive polymers having a high positive temperature coefficient characteristic, which are connected in parallel. They can automatically adjust the output power according to the temperature changes of the heated system, automatically limit the heating temperature, can be cut to any length or extended within a certain range for use, and allow multiple crossings and overlaps without the risk of high-temperature hotspots or damage.
