Application of Shielded Electric Pump in Catalytic Reforming Unit
December 01, 2023
Shielded electric pump is developed by the atomic energy industry on the special requirements of non-leakage. In recent years, the application of shielded electric pump in the flammable and explosive petrochemical industry has been gradually expanded and its technology has matured.
The main types of shielded electric pumps are the following:
Basic: The pump body is mounted directly on the motor flange, suitable for general liquids.
Reverse cycle: the pump body mounted directly on the motor flange, suitable for easy vaporization liquid.
High temperature separation type: Suitable for hot medium oil and hot water and other high temperature liquid.
High melting point pump: used in high melting point easily crystallized liquid.
Mud seal pump: suitable for conveying mixed liquid mud.
Shielded electric pump centrifugal pump belongs to a special form, mainly by the pump, impeller, stator, rotor, front and rear guide bearing and the drive plate. The motor is integrated with the pump. The stator and rotor surfaces are respectively surrounded by non-magnetic thin-walled materials. The rotor is supported by the front and rear guide bearings and immersed in the conveying medium. Rotor shaft equipped with impeller, the formation of a structure without shaft seal, in order to achieve the purpose of non-leaking transport. High-pressure liquid discharged by the impeller for circulating cooling liquid to remove heat, according to the different transmission medium, circulating cooling is divided into positive cycle, reverse cycle and external cycle three.
As the reforming equipment conveying medium except hydrogen, mainly naphtha liquefied petroleum gas, so the reformer can be used on the basic type, reverse cycle, LPG pumps on the ground, from the use of the situation have reached the process requirements .
Shielded electric pump with bearing wear detection system, the relative space 1800 in the two stator teeth around a symmetrical pair of coils, when the rotor rotates, it will induce a phase difference 1800 potential. In the normal operation of the bearing, the fundamental frequency of the two windings in the same direction and the opposite direction, so the electrical junction box connected to the instrumentation signal shows only the difference between harmonics, the pointer in the green zone. When the bearing wear increases, the harmonics and fundamental wave difference between the coils increases significantly, so that the pointer biased to the yellow zone or red zone, to remind the operator to take measures. In addition, the shield pump direction of rotation can also be automatically detected.
Shielded electric pump a large investment costs, but the use of maintenance costs than the average mechanical seal pump is much lower. Shielded electric pump wearing parts (guide bearing) service life is generally 12 months, and the average mechanical seal life of 4 months, according to the cumulative cost of using 5 years, the use of shielded electric pump and the use of mechanical seal pump The total cost is roughly the same. Zepp petrochemical plant reformer using 12 sets of shielded pump proved that shielded pump in eliminating leakage, reduce maintenance costs, to ensure safe production and improve the overall economic efficiency and other aspects of the promotion value.
