由上图可知，总体上二氧化碳的密度随着压力的增大而增加，随着温度的升高而

由上图可知，总体上二氧化碳的密度随着压力的增大而增加，随着温度的升高而减小，在液态时其密度能够超过1000kg/m³，而气态时最小接近45 kg/m³，因此控制好压 力和温度就可以控制其密度状态，当二氧化碳处于液态时密度最大，随着温度的升高进入到气相状态，二氧化碳的密度迅速减小，但是随着温度与压力的进一步提高，进入到超临界状态时，其密度又会迅速增加，虽然小于液态的，但是远远大于气态时的，而超临界状态较液相的实现简单，因此在大规模应用中更容易实现，由于密度较高所以相比气相的输送效率高，利于管道输送。

As shown in the above figure, the overall density of carbon dioxide increases with increasing pressure and decreases with increasing temperature. In the liquid state, its density can exceed 1000kg/m ³， In the gaseous state, the minimum is close to 45 kg/m ³， Therefore, controlling the pressure and temperature can control its density state. When carbon dioxide is in the liquid state, its density reaches its maximum. As the temperature increases, it enters the gas phase state, and the density of carbon dioxide rapidly decreases. However, as the temperature and pressure further increase, when it enters the supercritical state, its density will rapidly increase. Although it is smaller than the liquid state, it is far greater than the gas state, and the implementation of the supercritical state is simpler than that of the liquid phase, Therefore, it is easier to achieve in large-scale applications, and due to its higher density, it has higher transportation efficiency compared to gas phase, which is beneficial for pipeline transportation.

As can be seen from the above figure, the density of carbon dioxide generally increases with the increase of pressure and decreases with the increase of temperature. In liquid state, the density can exceed 1000 kg/m, while in gas state, the minimum density can be close to 45 kg/m, so the density state can be controlled by controlling the pressure and temperature. When carbon dioxide is in liquid state, the density is the highest, and when the temperature increases, it enters the gas state, the density of carbon dioxide decreases rapidly. However, with the further increase of temperature and pressure, when it enters the supercritical state, its density will increase rapidly, although it is less than that of the liquid state, but it is far greater than that of the gas state. The supercritical state is easier to realize than the liquid state, so it is easier to realize in large-scale applications. Because of its higher density, it is more efficient than the gas phase and is beneficial to pipeline transportation.