Petrochemical field

working principle

The temperature sensor on the tank conveys the sensed temperature to the temperature control meter in the intelligent temperature control distribution box through the signal cable. The temperature control table compares the received temperature with the set temperature, and the current temperature is greater than the set temperature. When the electric heating is not working, when the current temperature is lower than the set temperature, the electric heating starts to work. In order to avoid frequent starting, a hysteresis is generally set, and the distribution box can also be connected to the central control room or DCS system by remote communication. It can remotely observe and control the start and stop of the electric heating cable.

Construction installation

When installing the electric heating cable on the tank, the surface of the tank should be smoothed first, then a layer of wire mesh should be laid on the tank (or glue the nails on the tank or welded hooks on the tank), and finally install electricity. In the heating cable, after installation, a layer of aluminum foil is covered along the direction of the electric heating cable to increase the heating area of the tank. The installation spacing is obtained by calculating the heat dissipation and surface area of the tank. For details, refer to the 16S401 atlas.

working principle

The skin electric heating is mainly realized by the "skin effect" and "proximity effect" of the alternating current. The so-called skin effect is a phenomenon in which the alternating current passes through the carbon steel conductor and the current gradually forms on the surface of the conductor. The proximity effect is an electromagnetic phenomenon between a pair of opposite-current electric currents. When the electric current is passed between the cable and the heat pipe in the heating pipe, this heat is the heat required for the heat tracing.

Construction installation

The carbon steel pipe is welded to the pipe, the skin cable is inserted into the carbon steel pipe, the carbon steel pipe and the skin cable are short-circuited at the tail end, and the first end is connected to the power source. The carbon steel pipe and the pipe are filled with a thermal conductive cement to increase the heat dissipation area.

Because the pipes for skin heating are generally long, most of them are several kilometers. In this case, the power transmission requirements for signal transmission are extremely high. Remote communication is achieved through fiber optic or PLC systems.