Clean Forest – Project concept and preliminary results

Abstract

The aim of this project is to valorize forest biomass wastes into bioenergy, more precisely, production of 2nd generation synthetic biofuels, such as, biogas, biomethanol, bio-DME, etc., depending on process operating conditions, such as, pressure, temperature and type of solid catalyst used. The valorization of potential forest wastes biomass enhances the reduction of probability of occurrence of forest fires and, presents a major value for local communities, especially, in rural populations. Biogas produced can be burned as biofuel to produce heat and/or electricity, for instance, in cogeneration engines applied for domestic/industrial purposes. After the removal of forest wastes from the forest territory, this biomass is dried, grounded to reduce its granulometry and liquified at temperatures between 100-200 ºC. Then, using the electrocracking technology, this liquified biomass is mixed with an alkaline aqueous electrolyte located in an electrolyser (electrochemical reactor which performs an electrolysis process), using a potential catalyst, in order to produce syngas (fuel gas, mainly composed by CO, H2 and CO2). In a second reaction step, this syngas produced can be valorized in the production of synthetic biofuels, in a tubular catalytic reactor. The whole process is easy to implement and energetically, shows significative less costs than the conventional process of syngas gasification, as the energy input in conventional pyrolysis/gasification process is higher than 500 ºC, with higher pressures, while, in the electrochemical process, applied in this project, the temperatures are not higher than 70 ºC, with 4 bars of pressure, at maximum. Besides that, the input of energy necessary to promote the electrolysis process can be achieved with solar energy, using a photovoltaic panel. In the production of biogas in the catalytic reactor, there is another major value from this process, which is the co-production of water, as Sabatier reaction converts CO2 and H2 into biomethane (CH4) and steam water, at atmospheric pressure, with 300 ºC of temperature, maximum, with a high selective solid catalyst. Finally, it is expected to produce a new bio-oil from this kind of biomass, with properties more closer to a fossil fuel than wood bio-oils, which can be used as a fuel or as a diolefins/olefins source and, also, to produce, from forest biomass wastes, pyrolytic bio-oils with complementary properties and valorised characteristics. This can be used in wood treatment or as a phenol source, for several industrial applications. A new and valorised application can be found for forest biomass wastes, which can be incorporated in the biorefinery concept.