Waste to energy: Exploitation of biogas from organic waste in a 500 W el solid oxide fuel cell (SOFC) stack Davide Papurello a, b, * , Andrea Lanzini a , Lorenzo Tognana c , Silvia Silvestri b , Massimo Santarelli a a Department of Energy (DENERG), Politecnico di Torino, Corso Duca degli Abruzzi, 24,10129 Turin, Italy b Fondazione Edmund Mach, Biomass and Renewable Energy Unit, Via E. Mach, 1, 38010 San Michele a/A, Italy c SOFCpower spa, V.le Trento 115/117, Mezzolombardo, TN 38017, Italy article info Article history: Received 30 October 2014 Received in revised form 6 February 2015 Accepted 11 March 2015 Available online xxx Keywords: SOFC Biogas PTR-MS Trace compounds Nickel anodes Gas cleaning section abstract Organic waste collection from local municipal areas with subsequent energy valorization through CHP systems allows for a reduction of waste disposal in landfill. Pollutant emissions released into the at- mosphere are also reduced in this way. Solid oxide fuel cell (SOFC) systems are among the most promising energy generators, due to their high electrical efficiency (>50%), even at part loads. In this work, the local organic fraction of municipal solid waste has been digested in a dry anaerobic digester pilot plant and a biogas stream with methane and carbon dioxide concentrations ranging from 60e70 and 30e40% vol., respectively, has been obtained. Trace compounds from the digester and after the gas clean-up section have been detected by means of a new technique that exploits the protonation reactions between the volatile compounds of interest and the ion source. Sulfur, chlorine and siloxane compounds have been removed from as-produced biogas through the use of commercial sorbent materials, such as activated carbons impregnated with metals. A buffer gas cylinder tank has been inserted downstream from the filtering section to compensate for the biogas fluctuations from the digester. The technical feasibility of the dry anaerobic process of the organic fraction of municipal solid waste, coupled with a gas cleaning section and an SOFC system, has been proved experimentally with an electrical efficiency ranging from 32 to 36% for 400 h under POx conditions. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The increasing demand for fossil fuels has led to intense research and development efforts towards renewable energy sources (RES). This increased interest is reflected by the significant increase in the publication of patents on renewable energy (solar, wind, biomass, etc.), see Fig. 1 [1]. In this research area, the biomass produced from a photosynthesis process, with an almost net zero CO 2 emission balance, contributes to the reduction of CO 2 emis- sions. Interesting results have been achieved by exploiting organic waste, and, in this context, the waste from the separate collection of local municipalities plays a central role. The study by Andersen et al. (2012), for instance, shows how the environmental impact of home composting is generally quite low compared to the inciner- ation and landfilling options [2] as far as several impact categories are concerned (especially in terms of nutrient enrichment, acidifi- cation and eco-toxicity in water). The conversion of biomass into energy can be attained through different technologies: combustion, gasification and anaerobic digestion. Combustion is the simplest and most consolidated technical process: it involves using a burner in which the biomass is burnt. The combusted gas is then used to heat up a traditional boiler in order to actuate a turbine in a steam cycle. The gasification process allows a syngas rich in hydrogen and carbon monoxide to be produced with a relatively high LHV. This syngas is then exploited to produce energy in power devices. A possible alternative to the production of energy with biomass is that of anaerobic digestion. Anaerobic digestion, despite the com- posting process, allows not only matter but also energy to be recovered from bio-waste. The anaerobic fermentation of organic matter is influenced to a great extent by the pre-treatment pro- cesses that are used to liberate the sugars needed for fermentation [3e5]. Many types of pre-treatments have been mentioned in * Corresponding author. Department of Energy (DENERG), Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy. Tel.: þ39 0110904495/þ39 3402351692. E-mail address: davide.papurello@polito.it (D. Papurello). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2015.03.093 0360-5442/© 2015 Elsevier Ltd. All rights reserved. Energy xxx (2015) 1e14 Please cite this article in press as: Papurello D, et al., Waste to energy: Exploitation of biogas from organic waste in a 500 W el solid oxide fuel cell (SOFC) stack, Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.03.093