Abstract
Hydrogen and fuel cells combination is the most viable answer to the antithetic problems of growing energy demand and environmental pollution reduction. Due to the well note difficulties in H2 transport and storage, distributed H2 production results the most promising solution, so very compact and small size production plants are required. To this goal, hydrocarbons ATR reaction assures a self-sustaining process and high reactor compactness, resulting as the best method for distributed H2 production to couple to a fuel cell system. In spite of the increasing interest in renewable sources, due to the low costs and the widespread existing delivery pipelines, fossil fuels reforming still remain the best choice in a transition period towards hydrogen based economy.
In this work a compact catalytic reactor was analyzed for the ATR of CH4 as natural gas surrogate. Structured catalysts (commercial honeycomb and foam monoliths) performances in CH4 processing were studied. In reactor design, great attention has been paid to the thermal integration, in order to obtain a total self-sustainability of the process avoiding additional external heat sources, and improve the plant compactness. Through an heat exchange system integrated in the reactor, water and air stream are preheated by exploiting the heat from exhaust stream, allowing to feed reactants at room temperature as well as cooling product stream at a temperature suitable for further purification stages (WGS, PROX). In order to have a very comprehensive process analysis, temperatures and composition were monitored in 6 point along the catalytic bed. The influence of catalytic system geometry as well as thermal conductivity in the process performances was also analysed. Preliminary tests showed high thermal system efficiency, with a good hydrocarbon conversion at different operating conditions for both catalyst typologies.
