LIGNOCELLULOSIC BIOMASS PRETREATMENT FOR BIOFUEL PRODUCTION

The energetic crisis of recent years, as well as the increasing greenhouse gas emissions, have created premisesfor identification and exploitation of new, non-polluting and economic energy sources. Thus, have appearedconcerns in the field of biofuel production from renewable materials.Worldwide, biomass is considered the most valuable source of alternative energy to fossil fuels. Lignocellulosic biomass, consisting of agricultural and forest residues, animal manure and energy crops,is considered the main substrate for the production of second-generation biofuels (biogas, bioethanol etc).The main components of lignocellulosic materials are cellulose, hemicelluloses and lignin which is the most recalcitrant component of the plant cell wall (the higher the proportion of lignin, the higher the resistance to chemical and enzymatic degradation).In this paper there are presented the main pretreatment methods of lignocellulosic biomass, including mechanical, biological, chemical and thermal pretreatment, with the focus on the principles, advantages and disadvantagesof each method for biofuelsproduction.

THE INFLUENCE OF THE SPEED OF REVOLUTION OF A HAMMER MILL ON MISCANTHUS CHIPPINGS

Taking into consideration the fact that biomass is gradually replacing the existent energy resources, it is necessary to know the preparation process. The first step of this process takes place from the harvesting stage that can be done with or without cutting. High volume of biomass represents an impediment in its usage as a final product. It is necessary to transform it in pellets or briquettes. Thus, each stage of the preparation process was studied by researchers both for establishing the influence of biomass properties on the process as well as for designing the equipment used for preparation process. In this paper experimental research regarding the influence of the speed of revolution of a hammer mill on miscanthus chippings were done. The usage of hammer mills it happens in generally during the second stage of preparation process which refers to fine grinding process of vegetal biomass