• methane
• hydrogen sulfide
• dry reforming
• detailed reaction mechanism
• acid gas
• nickel based catalyst

Global warming, pollutant emission and increasing energy demand have gained attention in the past few years. Syngas production through reforming process represents an evaluable solution as clean alternative energy source.
This study focuses on the experimental investigation of reforming processes, aimed to the production of syngas with high concentration of hydrogen from two different syngas’ sources, methane and hydrogen sulfide. This thesis reports only one part of the study, which is related to the opportunity to convert the acid waste stream derived from the natural gas well, composed primary by H2S and CO2 and trace of CH4, in more valuable syngas through reforming process.
With the increasing of the exploitation of sour nature gas, concerns are growing over acid impurity contained in it, which are harmful to human health, industrial equipment and environmental. Several and expensive processes have been developed to reduce the emission of the acid substances, which are necessary but can make the exploitation of the fossil fuel uneconomic. The possible to convert the waste acid stream in more valuable syngas is a desirable alternative.
CH4 and CO2 obtained from the low quality natural gas are potentially efficient for ca dry reforming to syngas mixture. Enhanced catalytic conversion using Ni based catalyst provides economic performance but can result in deactivation due to carbon deposition and sintering, which calls for modification or promotion of the catalyst.
The effect of adding alkali barium to Ni-alumina catalysts has been studied. The dry reforming of methane has been carried out at 650 °C, 700°C and 750 °C over alumina supported Nickel catalysts with 0%, 2 % and 4% content of Barium. Addition of barium reduces the carbon deposition and increase the CO2 conversion. The promoter effect was not directly proportional to barium content. The stability of the catalyst has been tested for 2 hours, the results reveal that the Barium did not affect the stability of the catalyst for the exanimated duration.
Experimental results on hydrogen production from hydrogen sulfide and methane mixture are presented. The reformation of H2S in natural gas represents an unique opportunity for the treatment of highly sour gas and a potential alternative to the Claus process. A laboratory quartz-scale reactor was used to quantify experimentally the transient speciation of hydrogen and other products in the range of temperature of 1000°C-1400C°.
The results show the important role of the reactor temperature on the decomposition of both H2S and CH4. The increase in temperature reduces significantly the residence time required to reach the asymptotic steady state value. The conversion of H2S in presence of methane results higher than that produced from the only thermo-dissociation due to the consumption of one of the products, which is sulfur, to form CS2.
The kinetic mechanism that characterized the C-H system has been extensively investigated, while studies about the sulfur chemistry able to describe the reforming process is rather limited. This study presents a kinetic mechanism able to predict H2S kinetic behavior during the reforming process with methane, which are used to understand the reactions that mostly affect the process. Chemical kinetic pathways under high temperature conditions are evaluated in order to obtain information useful for significant process improvement.