Research on the Hydrate Formation in the process of Gas Phase CO2 Pipeline Transportation

With the development of the third oil recovery in oil fields and CO2 capture, utilization and storage (CCUS) technology, CO2 injection has become an effective means to enhance oil recovery (EOR) and relieve the greenhouse gas effect. The CO2 pipeline transportation technology started relatively late in China, where the gas phase and liquid phase transportation are widely used methods. The CO2 hydrate formation in the process of transportation may reduce the valve, destroy the equipment and even cause pipeline ice blockage, but research in China on CO2 hydrate is not very extensive. In this paper, the CO2 hydrate formation conditions were simulated using HYSYS, and the simulation results were compared with the experimental results to verify the feasibility of the simulation method. Based on this, factors in the influence of gas impurities on CO2 hydrate formation are simulated, and the pipeline transportation process of CO2 hydrate formation are predicted. The results show that when there is a low amount of impurity content, the gaseous impurities such as CH4, N2, H2, O2, have little effect on CO2 hydrate formation in gaseous CO2 pipeline transport. Furthermore, environmental temperature has little effect on the changes in pipeline pressure along the transport route. However, with a change in environment temperature, temperature along the pipeline changes greatly. CO2 will change from a gas state to a liquid state in the pipeline when the ambient temperature is low. In the case of low ambient temperature, a thick insulation layer should be used, and heating of the pipeline may also be required. When the ambient temperature is higher than about 10 , there will be no hydrates formed in the pipeline.