To improve the efficiency of offshore natural gas exploitation, CO2 separation from offshore natural gas in quiescent and flowing states using 13X zeolite was studied systematically by examining the voidage, adsorption time, inlet velocity, adsorber diameter, temperature, and pressure. An adsorption purification model was established and validated based on the experimental data. In quiescent adsorption, the contact area between 13X zeolite and the gas mixture is the most important factor for evaluating the adsorption purification efficiency, and higher voidages in the range of 0.25-0.50 were favorable for gas adsorption. However, in addition to the contact area, the contact time is an important factor for flowing adsorption. The purification efficiency of flowing adsorption is highest at a voidage of 0.35. At this voidage, the pressure drop in the adsorber was 70 Pa. The stabilization time for adsorption equilibrium decreased with increasing inlet velocity. As the adsorption time increased, the adsorption heat at different axial lengths of the adsorber tended to reach a constant value, while a symmetric adsorption heat curve was observed at different radial lengths. Toward the reduction of the energy consumption in the adsorption process, the optimum adsorber lengths for different diameters, temperatures, and pressures were determined. Adsorption purification was enhanced with increasing temperature. Further, it could also be improved by an appropriate pressure. Optimization of the adsorber structure parameters and regulation of the state parameters during the adsorption process are important for reducing energy consumption and improving the purification efficiency. The findings of this study serve as a guide for setting the purification parameters for CO2 separation from offshore natural gas in engineering applications.