Glycerine is an ideal feedstock for hydrogen production. In addition to carbon and oxygen, it contains several hydrogen atoms. Glycerine is also non-toxic, easy to handle and available all year round.
To produce hydrogen with as low a carbon footprint as possible, however, the glycerine must be obtained from renewable resources. Biodiesel production, for example, uses plant oils to make diesel. It also generates large amounts of glycerine as a by-product, which is an ideal renewable feedstock.
Proof of concept
Linde Engineering has developed a method of manufacturing green hydrogen from biogenic glycerine and is currently trialling this technology at one of its pilot plants in Germany. The plant covers the entire production process from purification and distillation through pyroreforming to steam reforming. To save costs, the synthesis gas from the pilot plant is then fed into the conventional H2 production process, where it is purified to increase the yield.
Taking the full emission chain into account – from the delivery of glycerine to the electricity consumed by the pilot plant – the new process can reduce total CO2 emissions from a commercial-scale hydrogen production plant by 80 percent.
Linde Engineering is also investigating ways of producing H2 from other biogenic substances such as organic waste and other biomass feedstocks. The methane-rich gas generated by the gasification of biomass, for example, can also be converted into hydrogen. This process is particularly efficient, since the gasification residues serve as fuel, providing the heat required for the reaction.