Modelling and Analyzing the Impact of Hydrogen Enriched Natural Gas on Domestic Gas Boilers in a Decarbonization Perspective

Decarbonization of energy economy is nowadays a topical theme, and several pathways are under discussion. Gaseous fuels have a fundamental role for this transition, and the production of low carbon-impact fuels is necessary to deal with this challenge. The generation of renewable hydrogen is a trusted solution since this energy vector can be promptly produced from electricity and injected into the existing natural gas infrastructure, granting storage capacity and easy transportation. This scenario will lead, in the near future, to hydrogen enrichment of natural gas, whose impact on the infrastructures is being actively studied. The effect on end-user devices such as domestic gas boilers, instead, is still little analyzed and tested, but is fundamental to be assessed. The aim of this research is to generate knowledge on the effect of hydrogen enrichment on the widely used premixed boilers: the investigations include pollutant emissions, efficiency, flashback and explosion hazard, control system and materials selection. A model for calculating several parameters related to combustion of hydrogen enriched natural gas is presented. Guidelines for the design of new components are provided, and an insight is given on the maximum hydrogen blending bearable by the current boilers.