Biomass for sustainable energy production
The technology for methane generation from biomass is well established. However, engineering and technical advancements are required to convert this process into a cost-effective and competitive energy supply. The overall objective of the EU ‘Renewable energy from crops and agrowastes’ (Cropgen) project was to produce from biomass a sustainable fuel source that can be integrated into the existing energy infrastructure. The study concentrated on the use of anaerobic digestion of crops to produce methane. As a first step, project partners reviewed the crops and plants suitable for growing in European locations. These were evaluated based on the biomass to biogas yield, input energy requirements and secondary crop uses. To assess the crops’ potential methane yield, researchers used the biochemical methane potential (BMP) test. Various factors including material preparation, particle size and silage additives were also tested for their ability to influence the BMP value. Moreover, different biomass pre-treatment methods were tested to minimise energy losses. The consortium also researched better reactor designs. They developed a two-phase system in which the bed liquors were replaced by clean liquids, flushing out acid products and maintaining a stable pH that would allow further solids destruction. Such a bioreactor operation was seen to enhance biomass processing and energy output. To model the process of anaerobic digestion, a software tool was developed in the form of a virtual laboratory to allow monitoring of methane production, pH and acids concentration. Additionally, a fuzzy logic control tool enabled the calculation of organic loading rate and methane production by controlling input factors such as the fatty acid concentration and pH. Collectively, the Cropgen project performed thorough analysis of a plethora of factors involved in the energy production from agricultural biomass. Project achievements are expected to have important implications in biogas technology and aid its establishment as an economically attractive energy production process.
