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Clean Techn Environ Policy (2015) 17:797801
DOI 10.1007/s10098-014-0866-9
ORIGINAL PAPER
Processing of residues from biogas plants for energy purposes
Josef Marouek Simona Hakov
Robert Zeman Jan Vchal Radka Vankov
Received: 2 June 2014 / Accepted: 11 October 2014 / Published online: 8 November 2014 Springer-Verlag Berlin Heidelberg 2014
Abstract Maize silage (Atletico, FAO 280) is being anaerobically fermented with cow manure (45 C, pH 7.1, hydraulic retention time 67 days) in a commercial scale (8,210 MWh electric power and 8,700 MWh heat power per year). The fermentation residues are being mechanically separated into the liquid fraction and the solid pulp(0.9 % hemicelluloses, 8.4 % cellulose, 5.7 % lignin). The solid pulp is being predryed and subsequently pyrolyzed. The pyrolysis takes place in the newly developed horizontal continuous pyrolysis reactor. The technology is run by the hot ue gases (410 11 C) from the biogas combustion engine (383 m3 of biogas per hour). The carbon powder obtained is being technologically and economically analyzed as a solid biofuel instead of biochar. The results obtained by standardized methods show that the new variety of products obtained outperforms many of the conventional solid biofuels not only in technological and environmental indicators, but also from the economical point of view.
Keywords Sustainable technologies Waste energy
Waste materials Biofuels
Introduction
Biochar is a carbon powder obtained by pyrolysis of lignocellulose at the absence of air, respectively, oxygen. Due
to its high porosity, it used to be a traditional improver of soil fertility, however, its current prices make this old practice difcult. Notable effort to reduce the cost was published recently (Marouek 2014). The novelty is based on processing of waste phytomass (instead of costly wood) and waste energy (instead of utilization of the energy obtained from the lignocellulose itself). In addition, it was proved that if the waste material was previously subjected to anaerobic fermentation, the microporosity (quality) is higher due to the removal of fermentable parts of the organic matter. Despite all the positive environmental aspects (Bare 2014; Garmestani 2014), the tradition of biochar application survived only in the rural parts of East Asia and Africa. Therefore, it is not surprising that the initial market analysis supported by the study on agriculture decision-makers behavior (Marouek et al. 2014) showed...