The alumina, in the form of α-Al₂O₃ tabular balls, considered in this study is a high-purity form of aluminum oxide that has been fired at high temperatures (well above 1900 °C), virtually removing porosity. However, the purity and inertness of the surface of the Al₂O₃ tabular balls minimize the catalytic activity, which is why lithium doping was tried. Thus, the target of this study was the effect of doping with lithium ions in some tabular balls of Al₂O₃ (the crystalline structure is corundum) on the improvement of the catalytic properties of alumina. This study examined the impact of a lithium catalyst on the combustion of various fuels within a porous inert medium (PIM) burner. This study specifically compared low calorific gaseous fuel (e.g., biogas) combustion in a PIM burner with and without the lithium catalyst. The experimental setup comprised a gas preparation unit for mixing CNG and CO₂ to simulate biogas and a PIM burner. The PIM burner comprised Al₂O₃ spheres (13 mm diameter, 45% porosity) in a random packing configuration. Three fuels, varying in composition and lower heating value (LHV ranging from 20.771 to 27.695 MJ/m³), were combusted at air ratios ranging from 1.67 to 1.79. The results indicated that the catalyst increased peak combustion temperatures by 23.2 °C to 51.4 °C, depending on the fuel type and air ratio. Significantly higher carbon monoxide (CO) concentrations were observed without the catalyst, particularly with fuel type F1, while nitrous oxide (NOx) levels remained consistently low. Upstream flame propagation was observed in the presence of the catalyst. These findings demonstrate the potential of lithium catalysts to enhance combustion stability and reduce emissions in porous media combustion burners. Following these studies, it can be stated that Li(I) has the role of promoter of the catalytic process.

Nowadays, the use for renewable resources comes as a necessity to stringent energetic consumption issues that are related to both economic and energy autonomy (if possible) by using alternative sources of energy. In this context, one possible solution could be the application of anaerobic digestion processes, with a main energy carrier as result in the production of biogas. The focus for the present paper is to analyze the possibility to obtain biogas through anaerobic digestion of solid agricultural wastes (degraded corn and wheat) in municipal waste waters substrate. The biogas production was tested on a self-sustained double biogas reactors and CH4 production obtained presented. Combustion of biogas-like syngas simulating produced biogas was performed in the presence of ZnAl2O4 and CoAl2O4 catalyst, in an experimental combustor. Experiments conducted showed that both corn and wheat blended with municipal waste water produce biogas with up to 80% CH4 concentration and that combustion behavior of biogas is improved in presence of CoAl2O4 catalyst.

In the context of increased energy demands and finding solutions for energetic autonomy, the use of waste base materials has increased in recent years in all areas of research. In this context, waste waters, sludge or slurry, biodegradable materials, second generation effluents, and their byproducts are some of the key substrates of interest to obtain biogas through AD (anaerobe digestion). The goal is to utilize these materials as a base for the generation of renewable energy and thereby make it the main source of energy for households or industries. This paper aims to characterize, from a physical and chemical point of view, wastewater from Timis county as a base substrate material in the co-fermentation process with cereal residual biomass. We aimed to determine the energetic potential of the wastewater and perform preliminary testing at a small and pilot-sized experimental installation for biogas production with Timis wastewater as the main energy carrier. The novelty of the paper stems from the use of a patented pilot installation as our experimental approach, as well as the use of a different comparative scale co-fermentation process for biogas production. The conclusions will be traced relative to the obtained results, and preliminary solutions will be proposed for further avenues on this topic.