Anaerobic digestion technology for Swedish conditions and experimental verification of increased biogas production from polyurethane and biomass retention

Abstract: Anaerobic digestion of farm waste has the potential to revolutionize the agricultural sector. There are four principal objectives of this report. Summarize anaerobic technology and biological function and how they affect the potential of farm scale anaerobic digest in a literary study. Economically evaluate farm scale scenarios where biogas is considered for upgrading, heating and electricity with an internal rate of return method. Simulate farm scale scenarios in the computer software Aspen Plus. In these scenarios biogas is utilised for upgrading, heating, electricity and compared to active anaerobic digesters. Investigate how polyurethane and retention of biomass effects an anaerobic digester through design of experiments. The economic evaluation was done by using the internal rate of return. The results indicate that all scenarios are warranted in different situations but that in the given scenario a CHP unit is the most profitable. Aspen simulations show great promise as a tool for evaluation of different digester systems. It could be used both for economical evaluations and in planning stages. The effects of polyurethane and retention of biomass was shown to effect the methane concentration in the test reactors with up to 15 percentage points and the biogas production with 32 percent. These two models were developed in Modde 10. Thru the literary study the importance for anaerobic digestion technologies to be adapted to conditions were they are to be deployed for them to be profitable were evident. The immense benefits of biogas production on the environment indicates the biogas production will play a part in the conversion to a sustainable energy system.