Hydrogen quality from decarbonized fossil fuels to fuel cells

Increased focus on curbing carbon dioxide (CO2) emissions and a limited and unstable supply of fossil fuel resources make diversification of energy resources a priority. Hydrogen has emerged as a promising energy vector for solving these issues. However, there are numerous challenges related to production, distribution and end use of hydrogen. Of particular importance is the link between hydrogen purity requirements for use in fuel cells and the capabilities of production. Impurities can adversely affect fuel cell performance and durability, and the fuel composition must therefore be carefully controlled. However, impurity specifications should be balanced against production and purification costs. This paper examines the effects of impurities on fuel cell performance and assesses the capabilities of hydrogen production from decarbonized fossil fuels to meet the purity requirements dictated by use in fuel cells. While carbon monoxide, hydrogen sulfide and ammonia impurities are shown to most negatively affect fuel cell performance, these species are also the most easily removed during purification. In hydrogen production from decarbonized fossil fuels, inert gases are the most limiting species in the separation. If inert gas specifications were relaxed, then carbon monoxide would become the most limiting factor.