At the first 204.4km, the liquid ca

At the first 204.4km, the liquid carbon dioxide pipeline always absorbs heat from the environment, which makes its temperature rise. However, through pressure analysis, when the distance exceeds 204.4km, due to the decrease of pressure, gas-liquid two-phase flow is generated, and the Joule-Thomson effect begins to stand out, which causes the temperature of the fluid in the pipeline to drop compared with before, as shown in the following figure, and the curve will be slightly upward.When the temperature of the medium in the supercritical carbon dioxide pipeline drops to the critical point of 30.95℃, the pressure is 12.9 MPa, and the transportation length of the pipeline at this time is 128.1km. As the pipeline length continues to increase, the supercritical nature of the medium will be destroyed. Therefore, if you want to keep the transportation under supercritical conditions all the time, the effective transportation distance of one-time pressurized heating is 128.1 km, and then further heating treatment is needed. However, generally, when the pipeline distance exceeds 128.1km, the pressure of the pipeline is still at a high level, which can fully meet the actual application requirements on site. When the specified pressure drop is 5% of the import, the transportation distance will reach 1010km, so if the requirements for supercritical conditions are not high, it can fully meet the actual production.