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The paper analyses the behaviour of cereal straw briquettes in combustion at energy installations equipped with fixed grates for powers below 75 kW, intended for uses in the field of agriculture. A comparison was made with the combustion of sawdust briquettes. A wider involvement of the energy use of cereal straws, which are in large quantities in certain agricultural regimes, is envisaged. The research includes a new production of cereal straw briquettes from the Oltenia area, previous research being carried out with briquettes made in the agricultural area of North-Eastern Moldova. The use of cereal straw for energy purposes, however, collided with the final processes of combustion when the ash becomes adherent to the elements of the combustion plant, so this new approach will contribute to broadening the knowledge about this biofuel that represents a certain future. The work presented experimental combustion tests comparing the two fuels (cereal straw briquettes and wood sawdust respectively) at a 55 kW pilot plant, plant equipped with a fixed grill. [ABSTRACT FROM AUTHOR]

The paper deals with mathematical model and experimental tests of hydrogen (pure or mixed) diffusion in the porous system of biomass. A mathematical model has been developed for gas diffusion in a porous system and based on it a numerical simulation for hydrogen absorption gas been carried out. The results are presented graphically and they point out that the concentration variation inside the pore decreases with the increases of pore length and increases with the increase of hydrogen flux. Also, the absorbed hydrogen quantity decreases with the increase of the pore length and for a given pore length the absorbed hydrogen quantity increases with the increases of hydrogen flux and internal pore surface. Research regarding hydrogen diffusion in the porous system of biomass is part of wider research focusing on using hydrogen as an active medium for solid biomass combustion. In parallel with hydrogen diffusion in solid biomass, tests regarding biomass combustion previously subjected to a hydrogen flux will be carried out. [ABSTRACT FROM AUTHOR]

Leather processing for commercial purposes involves going through a set of complex and laborious operations, resulting in over 70% waste relative to the initial feedstock; a quarter of this waste is produced in Europe. Worldwide there are about 36,000 companies active in this sector, generating a turnover of almost 48 billion euros. As in any industrial sector, waste recovery is a highly researched topic, with alternatives for its use being constantly considered. One of the most interesting solutions to this problem consists of using part of the waste for power applications. For instance, the 10% fats from total animal waste could well be employed to power diesel engines, both in raw state or as biodiesel. The remainder, which contains mostly proteins, can be exploited to obtain biogas through anaerobic digestion. This paper presents the results of experimental determinations on the combustion of animal fats and compares it to other biofuels, such as vegetable oils and solid biomass. The advantages of co-firing hydrogen-rich gas (HRG) and vegetable biomass are also analyzed. According to the presented results, combustion of the investigated fuels has a lower impact on the environment, with the concentration of pollutants in the flue gases being low. Thus, the paper proves that all the proposed solutions are ecological alternatives for biomass exploitation for energy recovery purposes, based on comparing the results in terms of pollutant emissions. This paper provides qualitative and quantitative perspectives on multiple alternatives of energy recovery from biomass resources, while also briefly describing the methods and equipment used to this end. [ABSTRACT FROM AUTHOR]