Real Application Case of Electric Heating Cable in Sulfuric Acid Pipeline in Chemical Plant

Published on:

2022-10-19 11:23

In chemical production, the temperature of the heated liquid must be maintained by heating the pipeline in order to prevent the liquid from solidifying when transported by pipeline. Steam heating is a traditional method of thermal insulation and heating of liquid materials during transportation and storage. Since the steam temperature is much higher than the temperature the liquid should maintain, steam heating often causes energy loss, and the insulation effect in winter is poor, and the steam heater freezes easily and affects performance. Especially in the transportation and storage of some highly corrosive liquid media, it is easy to cause local corrosion and perforation of the pipeline, and often flow and burst. Smudges, leaks, etc. not only threaten the safe operation of the finish, but also seriously pollute the environment.

A major chemical group in our province has decided to use our electric heating to insulate the sulphuric acid pipeline in a 100,000 t/year caustic soda plant. After one winter operation, the temperature control effect of the pipeline is better, fully meeting the technological requirements. Effectively eliminates the easy clogging of hydrochloric acid pipelines in winter, not only avoids large labor losses and material resources, but also avoids the operational risk caused by the blockage of sulfuric acid pipelines; The heating temperature can also reduce the corrosion of hydrochloric acid to pipelines.

The electric heating system mainly consists of two parts: the control unit and the electric heating cable. The control unit uses temperature control units, and each circuit is equipped with a temperature measurement point to track, measure and control the process temperature of the pipeline. At all times. Based on the specified temperature value, when the system temperature is lower than the set temperature, the circuit is automatically connected to increase the temperature of the pipeline process; when the system temperature is higher than the set temperature, the temperature control system automatically turns off. Power source and limit temperature: a set temperature is reached.

The plant's heating facilities are diluted sulfuric acid with a 75% mass fraction and concentrated sulfuric acid with a 98% mass fraction. The service temperature is 15 degrees Celsius, and the external texture temperature is:-20.1 degrees Celsius. DN80 pipe diameter, carbon steel material. The total length of the gas pipeline is about 800 m.

Based on the fact that the current pipeline technology is mature, materials such as heating cables are resistant to corrosion by acids and other environments, and the control temperature meets the process requirements, and automatic control cannot be realized. Use acid-resistant anti-corrosion and explosion-proof electric heating belt with self-temperature control.

Anti-corrosion and explosion-proof certification of explosion-proof electric heating belt with self-temperature control

Parameters of anti-corrosion and explosion-proof self-regulating heating cable

(1) Standard color: black/blue

(2) Temperature range: the maximum operating temperature is 65 ± 5 °C and the maximum temperature to be maintained is 90 °C.

(3) Design temperature: Polyolefin minimum-20 °C, Fluorine material minimum-60 °C

(4) Starting current: ≤ 0.5 A/m

(5) Thermal stability: After the electric heating belt has passed the thermal performance test, its power should be maintained at 90% of the original value.

(6) Bending radius: 25.4mm at-20 °C, 35mm at-60 °C

(7) Insulation resistance: The insulation resistance between the electric heating conductor and the metal shielding layer shall not be less than 50 MOM.

After winter operation in 2021, it has been proved that the heat preservation effect of the electric heating system is good, and the operation is stable and reliable, which ensures the normal operation of the sulfuric acid pipeline and the production system is safe and efficient. Since the self-regulating electric heating belt adjusts thermal power according to the wall temperature of the inlet pipe (environment) when it is applied to anti-freezing and heat preservation in industrial piping and equipment, it can accurately maintain the process temperature and eliminate equipment and pipeline failure due to local overheating. Corrosion and perforation caused by this can effectively prevent the launch, Leakage and dripping, improve the production environment of the enterprise, and get double profits from energy saving and environmental protection.

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