The formation of gas hydrate shows good potential to work as a separation medium for gas mixtures. However, to put it in practice, the impact of process parameters, such as flow rates, operational temperature and pressure are required to be adequately investigated. In this work, a new gas hydrate reactor is introduced for fast production of gas hydrate. The reactor is used for separation of carbon dioxide from methane in a series of semi-batch experiments. Results indicated that fast hydrate production is achievable. In addition, carbon dioxide is effectively separated from methane by producing gas hydrate from a gas mixture containing more than 60 carbon dioxide. © 2018 Institution of Chemical Engineers