The pressure ratio of the spiral steel pipe
on the gas pipeline also has a downward trend. For pipe diameter, pressure, and pressure ratio, it is necessary to carry out optimization calculations and comparisons. When the transmission volume is determined, after the pipe diameter, pressure, and pressure ratio are determined by optimization, if a higher pressure is selected and the steel strength grade is too low, the wall thickness will be too large, which will bring difficulties to many links such as pipe making, on-site welding, and transportation. difficult, even impossible to achieve.
Nowadays, thick-walled spiral steel pipelines
are mostly used in fluid transportation pipelines, and the transportation pressure of pipeline media has gradually increased in recent years, especially in gas pipelines. This is because increasing the transport pressure within a certain range will increase economic benefits. Taking gas pipelines as an example, under the condition of constant transport volume, as the transport pressure increases, the density of the gas increases, and the flow rate decreases, so that the friction resistance drops.
The demand for production has contributed to an increase in steel grades. The so-called pressure ratio refers to the ratio of the incoming pressure to the outgoing pressure. The reduction of the pressure ratio means that the entire line is operated at a higher pressure, which can also reduce energy consumption. In the early days, the pressure was mostly 1.6, and later it dropped to 1.4. In recent years, the pressure ratio of some gas pipelines abroad is 1.25. Of course, if the pressure ratio decreases, the number of compressor stations will increase, so the investment will increase.