Can PE pipes transport oil?

in the field of pipeline transportation, PE pipe (polyethylene pipe) is often used in water supply and drainage, gas transportation and other scenarios due to its advantages of corrosion resistance, good flexibility and convenient installation. But many people will ask: Can PE pipe be used to transport oil? This question cannot be simply answered with "yes" or "no", but must be analyzed in combination with the performance characteristics of PE pipe and the actual requirements of oil transportation.

PE pipe's core characteristics are "light, flexible and corrosion-resistant" - it uses polyethylene as raw material, the density is only 1/8 of that of steel pipe, and it does not require large machinery for handling and installation; it has strong flexibility, can adapt to terrain bending, and reduce the risk of joint leakage; it has good corrosion resistance to acid, alkali, salt and other media, unlike steel pipe, which is easy to rust. These advantages make it very popular in the civilian field, but in the oil transportation scene, it depends on whether it matches the demand.

The requirements for oil transportation are actually not simple: the first is the pressure - the crude oil transportation pressure is usually 1-10MPa, although the refined oil is slightly lower, it also needs to withstand a certain pressure; the second is the temperature - the crude oil often needs to be heated to 40-60 ° C (or even higher) to reduce the viscosity and facilitate the flow; and the medium composition - the crude oil contains wax, asphaltene, and some also carry corrosive gases such as hydrogen sulfide, which requires the temperature resistance, corrosion resistance and deposition resistance of the pipeline.

Can the PE pipe meet these requirements? Score:

1. Applicable scenarios: low pressure, room temperature light refined oil

If it is to transport low pressure (1.6MPa), room temperature (60 ℃) light refined oil (such as gasoline, diesel), PE pipe is feasible. For example, small gas stations in rural areas or short-distance oil pipelines, low pressure, short distance, PE pipe installation cost is 30% -50% lower than steel pipe, and will not be like steel pipe due to rust pollution oil. In this scenario, the corrosion resistance and flexibility advantages of PE pipe can be fully exerted.

2. Scenarios that cannot be applied: high pressure, high temperature or corrosive crude oil

but for crude oil (especially crude oil containing wax and hydrogen sulfide) or high pressure and high temperature transportation, PE pipe will "not be able to bear":

- Poor temperature resistance: PE pipe long-term use temperature generally does not exceed 60 ° C, and the temperature of crude oil after heating often exceeds this upper limit, which will lead to pipe softening, strength reduction, and even leakage;

- Limited pressure resistance: HDPE pipe The maximum working pressure is about 2.5MPa, which cannot withstand the high pressure of crude oil transportation (such as more than 5MPa);

- Corrosion resistance limitations: Although PE pipe is resistant to general corrosion, high concentration of hydrogen sulfide will accelerate its aging; crude oil wax, asphaltene is also easy to deposit in the pipe wall, affecting the flow;

- Lack of specification: There is currently no clear standard in China to allow PE pipes are used to transport crude oil, and more steel pipes or fiberglass pipes are used. The application of PE pipes is concentrated in the low-pressure scenario of refined oil.

To give a practical example: a southern rural gas station used PE pipes to transport diesel fuel 500 meters away, with a pressure of 0.8MPa and a temperature of 25 ° C, and it took 5 years without leakage; but a long-distance crude oil transportation project in an oil field, with a pressure of 8MPa and a temperature of 55 ° C, used spiral joint steel pipes, because PE pipes could not withstand such conditions at all.

In general, PE pipes are not "completely unable to transport oil", but are only suitable for low-pressure, room temperature, and weakly corrosive petroleum products. If it is high-pressure, high-temperature, or highly corrosive crude oil, its performance cannot meet the requirements.

Therefore, when choosing an oil pipeline, don't just look at the low price or convenience of PE pipes - you must first ask yourself three questions: whether to transport crude oil or refined oil? How high is the pressure and temperature? Is the medium corrosive? Find out these, and then judge whether the PE pipe is applicable.