Application of electric heating on the skin effect in the underwater oil pipeline

Published on:

2023-04-20 17:35

How to prevent the hardening and waxing of mixed oil and gas in subsea pipelines and ensure the normal transportation of oil and gas is the key to the rational and efficient development of remote sea areas.

It is generally accepted that the safe temperature range during oil transportation is: the maximum is no more than 10 ° C below the boiling point of crude oil, and the minimum is no less than 3 ° C above the freezing point of crude oil. Therefore, for a certain oil product, the maximum permissible temperature difference at the inlet and outlet of the underwater oil pipeline is determined. The temperature at the outlet of the subsea pipeline mainly depends on the inlet temperature, flow rate and heat loss along the way. The flow rate is limited to the flow rate It is generally accepted that the safe range of oil transportation temperatures is: the maximum is no more than 10C below the boiling point of crude oil, and the minimum is not lower than 3C above the freezing point of crude oil. Therefore, for a certain oil product, the maximum permissible temperature difference at the inlet and outlet of the underwater oil pipeline is determined. The temperature at the outlet of the subsea pipeline mainly depends on the inlet temperature, flow rate and heat loss along the way.

The flow rate is limited to output power and generally cannot be changed. After the calculation, the increase in the logistics filling temperature of the subsea pipeline is not efficient. At the same time, it is also limited to the initial boiling point of crude oil and the operating temperature of the subsea pipeline. In addition, the high population temperature makes the load on the subsea pipeline riser very large, so it should be considered. Underwater pipelines have heating, To reduce the thermal losses of the pipeline and reduce the temperature drop along the way. e.

Currently, the most widely used methods of heating pipelines include steam heating, hot water heating, and electric heating. Steam heating and hot water heating for underwater pipelines requires the addition of a large number of auxiliary facilities, a large investment, short service life, and a very complex design. Currently, the most widely used methods of heating pipes include steam heating, hot water heating and electric heating. Steam heating and hot water heating for underwater pipelines requires the addition of many auxiliary structures, the investment is large, the service life is short and the construction is very complex, so it is not suitable for use at sea. The self-regulating electric heating and constant power electric heating used to heat the pipeline on the platform cannot meet the needs of underwater heating of the pipeline, since the effective length of the heating circuit is no more than a few hundred meters.

For electric heating with a skin effect, the effective length of the heating chain can reach 25 km, so it can be used to heat the main pipelines. Leather effect electric heating pipes have been applied in many places around the world and have achieved good results.

Skin effect electric heating has the following advantages:

(1) The system control is simple. The system is mainly conventional equipment, easy to operate.

(2) Because the heat pipe is made of carbon steel pipe, and the wires are laid inside the heat pipe, the structure is durable and the service life is long.

The estimated life of the underwater pipeline may be unrepaired during the operating period.

(3) High thermal efficiency. Since the heat pipe and the inner pipe of the subsea pipeline are welded together, all the heat generated by the heat pipe and the wire is transferred to the sea.

The temperature difference between the inner pipe of the bottom pipeline, the heat pipe and the inner pipe of the subsea pipeline is small, usually not exceeding 10 °C.

(4) Thermal losses are small. Electric heating with a skin effect is applied, and the heating process is carried out along the entire length of the pipeline, so there is no need to worry about the presence of heating along the pipeline.

Heat loss causes the medium temperature in the pipeline to be lower than the safe oil supply temperature, and the subsea pipeline can be maintained at a relatively low temperature. The temperature difference between the pipeline and the environment is small, so the heat loss is small.

(5) No pollution.

Latest News

Please search according to your needs.