Efficient hydrogen separation using proton-conducting ceramic membranes and electrochemical cells

To achieve energy-efficient and low-cost hydrogen separation using proton conducting ceramic membranes for hydrogen rich streams generated through reforming of natural gas as well as onsite purification of hydrogen close to the point of end use for dilute hydrogen streams distributed through natural gas pipelines using ceramic proton electrochemical cells (hydrogen pumps). Hydrogen plays a vital role in helping the UK meet its 2050 target of net-zero greenhouse gas emissions through decarbonisation of its energy system including electricity, transport and heating sectors. Most hydrogen used today is produced from fossil fuels (e.g., through steam reforming of natural gas, coal gasification). The product gases consist mainly of H2 and CO2, as well as other impurity gases such as CH4, and CO. Therefore energy-efficient and low-cost hydrogen separation constitutes a crucial process to more toward to hydrogen economy.

Dense ceramic membranes made of mixed protonic-electronic conductors (MPECs) are capable of separating hydrogen from the gas mixtures with 100% selectivity, reduced energy penalty and cost compared to the well-established techniques such as the pressure swing adsorption technique. Ceramic proton conductors can also be used to fabricate electrochemical cells (hydrogen pumps) to obtain high purity hydrogen from dilute hydrogen streams when the existing hydrogen separation techniques become highly inefficient and costly. This is particularly important to facilitate distribution of hydrogen using existing natural gas pipelines. The ceramic proton electrochemical cells could enable extraction of high purity hydrogen from the natural gas blend with 10-20 vol% hydrogen close to the point of end use.