Application of electric heating in the offshore platform gas pipeline

Published on:

2023-04-25 11:20

At present, the gas pipeline between the gas block and the microturbine unit of the CNOOC Bohai Sea offshore platform is only insulated, and the heat loss is relatively large, so that the temperature of the natural gas entering the microturbine unit often does not reach the required temperature According to the owner's requirements, the temperature of the natural gas entering the microturbine unit is necessary. controlled at about 50 ° C, Therefore, it is necessary to design the electric heating for the gas pipeline to maintain the gas temperature at an applicable temperature.

Electric heating is to use electrical energy to generate heat to compensate for the heat loss dissipated by the heating pipeline and equipment in the process, in order to meet the temperature requirements of the medium in the process, so the calculation of the heat dissipation of pipelines and equipment is the premise of isothermal compensation, and relevant data should be collected for correct calculation.

In this project, it is necessary to control the temperature of the natural gas entering the microturbine plant at 50 °C. An explosion-proof junction box must be installed on site to provide power to the electric heating, and a thermostat must be installed to accurately control the heating temperature of the electric heating so that the natural gas pipeline is maintained at a temperature of 50 ° C, which meets the gas consumption requirements of the microturbine unit.

For the thermal losses of the gas pipeline, the prerequisite is the calculation of thermal losses. The key is to collect and organize the relevant data on the spot. The specific steps are as follows: the external dimensions of the heated pipeline (e. g., outside diameter, length, material, etc. E.) Pipeline;

Names, sizes and quantity of accessories such as piping and other equipment (e. g. valves, flanges, brackets, etc. E.);

Local minimum ambient temperature and maximum ambient temperature;

Optimal operating temperature and maximum or minimum allowable temperature to be maintained by the heated body;

Periodic maximum operating temperature of equipment and piping (e. g., purge temperature);

Variety and thickness of the insulating material;

What type of explosion-proof area is the installation environment, whether it is corrosive environment, indoor, outdoor or other environment;

The conditions and environment of the power supply at the facility (single-phase, three-phase, power supply, power supply location).

After a comprehensive comparison, we finally provided it with a self-regulating electric heating cable.

Self-limiting temperature electric heating is two parallel copper multi-core wires as a power bus, and the middle is evenly filled with conductive polymer materials as a heating core material. When power is applied to the tires, the current flows horizontally through the heating core material between the two tires, causing the core material to heat up and its resistance automatically increases accordingly. When the temperature of the core material rises to a certain value, the resistance is so great that it almost blocks the current, and the temperature of the core material no longer rises. At the same time, the core material transfers heat to the heated system through the shell, and the temperature drops. When the temperature drops to a certain value, the resistance gradually decreases, and the heating temperature of the core material rises again. By repeating this cycle, it is possible to maintain a constant temperature of the heated body.

Whether the correct choice and design of electric heating products depends on the normal operation of the entire electric heating system and whether it can meet the technological requirements for equipment. This also includes investment costs, operating costs, operational quality and service life of heating products, so the design and selection need to take into account not only the actual effect of using electric heating products, but also the economic effect. The cost of operating the system The general design principles are, generally speaking, reliability, applicability, economy and simplicity.

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