Should the friction loss of oil pipelines be calculated according to the isothermal oil transportation formula?

Why is the route of single-phase oil and gas pipelines not affected by terrain slope?

The first one to know, the physical parameters of the fluid corresponding to the average ground temperature (referring to the buried pipeline)

If it is a single-phase fluid, the problem of two-phase fluid does not need to be considered. The slope of the pipeline is usually not considered. However, if it is a two-phase fluid, if the two-phase flow problem cannot be handled well, liquid transportation problems may occur, such as liquid hammering. The understanding of isotherm: Because the pipeline is long and there is a heat exchange process with the outside world, the temperature is not calculated adiabatically, but isothermally calculated. This post was last edited by Albertlu on 2009-2-5 15:33 ]

If there is heat exchange, it is said to be isothermal, but I still don’t understand it:)

Should the friction loss of oil pipelines be calculated according to the isothermal oil transportation formula? It depends on the type of oil transported. Generally, refined oil is calculated according to the isothermal transportation formula.

If the crude oil flow rate is large and the pipe diameter is large, the heat generation problem can be considered, but generally there is no need to consider it with rough calculations.

Why is the route of single-phase oil and gas pipelines not affected by terrain slope? The route of single-phase oil and gas pipelines is affected by terrain slope. Your question is wrong.

The reason why the heat exchange mentioned on the 5th floor is isothermal is because if the heat generated is small and large, it must be considered.

Because I didn’t understand the original words in Teacher Huang Chunfang’s book, I raised this question. Regardless of whether long-distance pipelines transport single-phase or two-phase fluids, there will be liquid slugging. The answer on the 4th floor is inappropriate.

I remember that the book does not require calculation according to the isothermal formula. In fact, it seems to be written like this: It does not require particularly high accuracy. It is calculated based on the weighted average temperature between stations. This is how the pipelines are designed manually. Before the 1990s, almost all pipelines were calculated manually (except for the Donghuang Line teacher Liu Weimin who used a computer). After the 1990s, computers began to be used to design large-scale pipelines. For extra large pipelines, the differential principle is used to divide the pipeline into several sections. Each section is calculated according to the weighted average temperature. Finally, the calculation results of each section are added. The number of sections depends on your needs. Generally, the maximum temperature change of each section is 5 degrees (this can be done by hand and then use a computer). In short, there are two algorithms: 1. Calculation based on the weighted average temperature of pipe sections between stations. Suitable for manual design. 2. Calculation based on weighted average temperature between stations into several sections. The amount of calculation is large. If there are many sections, computer calculation is required. It is suitable for* * Design of large/extra large pipelines. The poster understands isothermal right. According to the differential principle, variable temperature pipelines should be divided into several sections. If the divisions are fine enough, they will be approximately isothermal.

Answers for other floors: Liquid pipelines do not take into account the intermediate height changes due to the siphon principle, but the overturn point must be considered (refer to Huang Chunfang, China Petrochemical Press, 2003, 2005, 2008 editions). If there is no siphon in natural gas pipelines, intermediate height changes must be considered (refer to Huang Chunfang, China Petrochemical Press, 2008, 2009 editions)

The friction loss of oil pipelines should be calculated according to the isothermal oil transportation formula because the result calculated based on the isothermal oil transportation is conservative and safe!

It depends on the type of oil being transported and the transportation process. Generally, refined oil, light crude oil, and low-freezing point crude oil do not need to be heated. They are calculated according to isothermal transportation pipelines. For those easily condensable and high-viscosity crude oil, heating transportation processes are usually used. At this time, the calculation method for heated transportation pipeline processes is used.