确定外部和内部条件后，对不同输送条件的管道利用Aspen Hysys进

确定外部和内部条件后，对不同输送条件的管道利用Aspen Hysys进行模拟计算，通过计算得知，如下图，气体状态下管道的压降最大，当输送距离为37.5km时，其压 降就超过了进口压力的5%，降到3.8MPa，因此依据压降，气态管道的有效输送距离仅 为37.5km；而液态和超临界状态的输送压降远远小于气态的，当管输距离在204.4km 以内时，这两种状态的压降都在允许范围之内，但是当距离超过此值时，液态管道中由于压力降低会发生相态变化，出现两相流体，相应的粘度会增加，造成管道的摩擦阻力增加，最终导致压降的增大，而超临界二氧化碳管道将会一直保持其较小的压降，且压降也呈线性增长方式，因此，单独从压降方面考虑，超临界状态管道输送由于气态和液态。

After determining the external and internal conditions, Aspen Hysys was used to simulate and calculate pipelines with different conveying conditions. Through the calculation, it was found that the pressure drop of the pipeline in the gas state is the highest. When the conveying distance is 37.5km, the pressure drop exceeds 5% of the inlet pressure, dropping to 3.8MPa. Therefore, based on the pressure drop, the effective conveying distance of the gas state pipeline is only 37.5km; The transportation pressure drop of liquid and supercritical states is much smaller than that of gas states. When the pipeline transportation distance is within 204.4km, the pressure drop of these two states is within the allowable range. However, when the distance exceeds this value, a phase change will occur in the liquid pipeline due to pressure reduction, resulting in two-phase fluid and corresponding viscosity increase, causing an increase in the frictional resistance of the pipeline, ultimately leading to an increase in pressure drop, And the supercritical carbon dioxide pipeline will always maintain its small pressure drop, and the pressure drop also shows a linear growth pattern. Therefore, considering the pressure drop alone, the transportation of supercritical pipelines is due to the gas and liquid states.

After determining the external and internal conditions, simulate and calculate the pipelines with different transportation conditions by Aspen Hysys. According to the calculation, as shown in the following figure, the pressure drop of the pipeline in gas state is the largest. When the transportation distance is 37.5km, the pressure drop exceeds 5% of the inlet pressure and drops to 3.8MPa. Therefore, according to the pressure drop, the effective transportation distance of the gas pipeline is only 37.5 km. However, the pressure drop in liquid and supercritical state is much smaller than that in gas. When the pipeline transportation distance is less than 204.4km, the pressure drop in these two States is within the allowable range. However, when the distance exceeds this value, the phase change will occur in the liquid pipeline due to the pressure drop, and the corresponding viscosity will increase, resulting in an increase in the friction resistance of the pipeline, which will eventually lead to an increase in the pressure drop. However, the supercritical carbon dioxide pipeline will always maintain its small pressure drop, and the pressure drop will also increase linearly.