Membrane gas separation is a process in which a gas mixture is separated into its individual components using a membrane. The membrane allows some gases to pass through while preventing others from passing through. In the case of separating hydrogen from a natural gas mixture, a membrane that is selective for hydrogen can be used.

There are several different types of membranes that can be used for hydrogen separation, including polymer membranes, inorganic membranes, and metal organic frameworks (MOF). Polymer membranes are made from polymers such as polysulfones and polyamides, and they are often used for separating hydrogen from natural gas mixtures due to their high selectivity for hydrogen. Inorganic membranes, such as ceramic and glass membranes, are also used for hydrogen separation, but they are generally less selective than polymer membranes. MOF are a relatively new type of membrane that have high surface areas and tunable pore sizes, making them highly effective at separating gases.

The process of separating hydrogen from a natural gas mixture using a membrane typically involves pressurizing the gas mixture on one side of the membrane, while maintaining a lower pressure on the other side. The hydrogen molecules are then able to pass through the membrane and into the lower pressure side, while the other gases are unable to pass through. The separated hydrogen can then be collected and used as a fuel or feedstock for chemical processes.

It's important to note that the efficiency of the separation process can be affected by a number of factors, including the type of membrane used, the pressure difference across the membrane, and the temperature of the gas mixture. In addition, the purity of the separated hydrogen will depend on the selectivity of the membrane and the composition of the starting gas mixture.

It is still a rather new and not well tested process. Nevertheless, using the present gas infrastructure is a great opportunity and it enables significant lowering of costs on H2 transportation and lowering its final price for a customer. A membrane separator itself is a relatively cheap device which has a potential in scalability. Unfortunately, even here we come across certain imperfection, for example an incomplete gas separation. This technology is also difficult to be used in sections which are branched. In this case, we are talking about a problem which is connected with uneven allocation of hydrogen in constituent branches. It could cause some customers to receive insufficient amount of hydrogen. A risk of a supplied energy shortage is generally obvious even from the whole idea of such a system. For example, if there were only 20 % of pipelines “reserved” for hydrogen, meaning for the only medium carrying energy for the end customer, there would be a significant reduction in accumulative and transferring capabilities of such a pipeline (Galík, 2021, s. 63).