• steam reforming
• wet impregnation method
• sorption enhanced steam reforming
• nickel based catalyst
• methane
• hydrogen production
• dry reforming

Global warming, pollutant emission and increasing energy demand have gained attention in the past few years. Hydrogen syngas production through reforming process represents a valuable solution as clean alternative energy source.
This thesis focuses on the experimental investigation of reforming processes, aimed to the production of syngas with high concentration of hydrogen from methane and CO2
For all the performed experiments we have studied and created catalysts with the aim of increasing the conversion and the performance of the process. The realization of catalysts has been provided by the use of the wet impregnation technique: this method consists in the impregnation of the support with an exact amount of metal solution such as to ensure complete absorption by the support. To perform this procedure is necessary to fix in advance the amount of support to be produced and the final percentage of the metal catalyst.
For all of our experiments alumina has been the chosen catalyst support due to its low cost and good value of the pore volume which results in a high metal solution that can be absorbed and so high metal percentage that can be achieved.
Steam reforming of methane is the most common process for hydrogen production as for H2 and CO syngas production; it is used in several industrial and chemical sectors and with electrolysis process seems to remain the main hydrogen source. The catalytic driven process is the most used and it has been studied in different process facility with particular attention in the material investigation; until now Nickel based catalysts are the most common choice in the industrial process both for their activity and their low cost. The main issue of this technology is the deactivation of the catalyst due to thermal sintering and carbon deposition. Latter researches are focusing their attention to promoter and doping materials able to decrease the deactivation; better results have been obtained with precious material, like Platinum, over perovskites supports.
In this thesis steam reforming of methane has been studied over 20 wt% NiAl2O3 catalyst as function of temperature and steam to carbon ratio. The better results have been funded for 700°C and S/C of 4, with more than 95% of methane conversion.
More interest in the last years has been given to a new technology that coupled the steam reforming with the CO2 sorption by a chemical sorbent: the sorption enhanced steam reforming of methane (SESRM). Calcium looping is one of the CO2 capture technique developed for Carbon Capture and Storage; this process is governed by the carbonation of CaO to absorb CO2 and form CaCO3, the formed CaCO3 is later calcinated at higher temperatures to regenerate the sorbent. In this process the CO2 evolved from water-gas shift reaction is absorbed by CaO reducing the concentration of carbon dioxide and enhancing the production of H2 by Le Châtelier's principle. One of the major issues facing CaO based SESR is that sorbents are found to gradually lose their CO2 sorption capacities due to the occlusion of surface pore sites by the deposition of CaCO3 product layer and to thermal degradation as the CaO formed during calcination is subjected to high temperatures.
In this thesis SESRM has been studied as a function of temperatures, catalyst types (in laboratory made or commercial), sorbent to catalyst ratio and steam to carbon ratio. Different parameters influence differently the equilibrium but it has been found that the higher H2 concentration is obtained at 600°C over commercial catalyst with S/C ratio of 4 and sorbent to carbon ratio of 3/2.
Another interesting reforming process is the dry reforming (DRM): a mixture of methane and carbon dioxide reacts over a catalytic bed to form an equimolar syngas of hydrogen and carbon monoxide. Even if the final composition of the syngas is not the more suitable for hydrogen production, this process is taking place like a form of carbon capture and utilization (CCU) of two main greenhouses gases.
In this thesis CH4/CO2 dry reforming has been investigated over 5 wt% Ni-Al2O3 catalyst as function of the temperature, GHSV (gas hourly space velocity) and CO2/CH4 feed ratio. Reactor conditions that promoted the conversion of methane are analyzed. As temperature and GHSV strongly effect conversion and selectivity, it has been founded that feed gases conversion is considerable improved at lower GHSV and higher temperature.