attivita
innovation for renovation
Agro-energy
Vegetable biomass has long been used on an industrial scale for power generation through a variety of technologies.
Solid biomass can either generate energy by means of direct combustion, or by being turned into gas or fluid fuel through gasification or pyrolysis. Biogas production from fermentable biomass through anaerobic digestion in special plants is now widespread. Moreover, oil crops (palm, rapeseed, sunflower, soy,..) can be crushed to produce fluid fuel to be burnt directly or in endothermal engines, or turned into biodiesel by means of esterification.
The interest for biomass is due to the fact that it has a favourable climate-altering emission net balance, meaning that energy generation from biomass causes the release into the atmosphere of the same amount of CO2 that had been previously absorbed from the atmosphere and turned into organic carbon during plant growth.
Opportunities for vegetable biomasses to further develop and spread on an industrial scale as a renewable source of energy depend both on technological improvements in energy conversion technologies and on the optimization of biomass production achieved by selecting high-yield varietals and enhanced agronomic techniques.
Asja is working in many different areas to develop biomass-to-energy processes:
1) Anaerobic digestion
Anaerobic digestion has by now become a well established industrial process for the treatment of farming sludges and some types of agricultural biomass.
Asja is engaged in optimizing treatment for biomasses of different origins like agricultural and food processing residues and the organic fraction of waste.
Optimization can maximize the performance of a process and make it applicable to discarded biomass which would otherwise have to be disposed of, e.g. waste, turning it into a valuable source of energy.
Moreover, innovative processes like “dark fermentation” which can lead to hydrogen production and to enhanced energy efficiency for the whole production cycle are currently being tested.
2) Gasification
Power generation from woody/cellulosic biomass is obtained through well established technologies whereby biomass is directly combusted. However, such processes are scarcely energy-efficient, plus, scale-related factors make their application to small sized plants (< 1MW) inadvisable. That is why research now goes in the direction of developing processes to produce fuel that can be used in high-yield power/heat cogeneration systems with endothermal engines. Namely, research is exploring the development of such processes for industrial applications.
Asja is also interested in testing and agronomically optimizing biomass-producing crops, especially the so called Short Rotation Forestry, that is short cycle tree crops such as poplar, willow, robinia, eucalyptus, paulownia, or annual grass crops such as miscanthus, switchgrass, giant cane, thistle and fiber sorghum.
3) Vegetable oils
Energy can be produced from vegetable oils being directly combusted in diesel cycle engines expressly modified for raw or refined vegetable oils.
Remarkable efforts are being devoted to optimize the energy yield of traditional oil crops like sunflower, rapeseed, soy and palm, and of other crops (Jatropha curcas, tobacco) grown specifically for energy production purposes. These efforts involve varietal selection and the improvement of agronomic techniques.
The possibility to employ used frying oils and animal fats is also of great interest.
Asja’s research into this area is aimed at adapting technology to these types of fuel, and developing oil treatment and purification processes which will improve these oils’ suitability for use in internal combustion engines.
4) Algae
Amongst the most innovative energetic biomass which are somehow in a less advanced stage of development, algae are certainly very interesting and hold great potential, for a number of reasons including:
- the quantity and quality of the biomass they can produce: according to the literature, their yield per hectare is higher than that of soil-grown crops
- their low environmental impact: to produce the same amount of biomass algae require less space, nor do they need agriculturally suitable soil or potable water, hence they can be grown in environmentally poorer areas with less economic and environmental resources
- the possibility to use them as biodepurators in heat plants; fumes from thermoelectrical power plants (such as internal combustion generator sets) contain CO, CO2 and nitrate oxides: these molecules have polluting effects when released into the atmosphere, but can instead be absorbed by vegetable cultures during growth. Therefore, algae crops can be useful in fumes treatment by abating their polluting charge while at the same time drawing essential nutrients therefrom.
