Modelagem Matemática da produção e transporte de biogás em aterros sanitários / Mathematical modeling of production and transportation of biogas in landfills

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

04/03/2010

RESUMO

The processes that occur within the landfill for the production of methane are the methane generation through biodegradation, transport of methane through a porous medium and sorption of methane through reactions with other compounds present in the landfill, especially oxidation. This work aims to develop a computer model to estimate the biogas production rate in landfills, a transport model to estimate the methane concentration inside landfills and use these models to estimate the biogas generation potential for the Santo Andre landfill. An evaluation of several existing models is performed for the biogas production through biodegradation and a set of coefficients is suggested for estimating the potential for power generation in landfills. The model was developed with the MATLAB system. It was considered conditions of regular and high humidity levels obtained through leachate recirculation. The results show that with regular moisture is possible generate, with reasonable probability, about 13,000 MWh of electricity for 15 years, and with high humidity, about 42,000 MWh. With high humidity, in about 5 years the landfill becomes almost inert and generates negligible biogas. A one-dimensional transport model of biogas was developed to determine the methane concentration within a landfill. It was introduced an explicit term for the consumption of methane through oxidation. This formulation facilitated the numerical solution of the problem, and, allowed analytical solutions for the methane concentration for uniform problems. The methane emissions to the atmosphere were determined for the Santo André site with and a without a coverage layer. It was found that an one meter coverage thickness reduces the leakage of methane to the atmosphere by 73 % when compared to the condition without coverage. Methane emissions to the atmosphere represented 18 % of the total generation, and the oxidation by the coverage layer represented 32 % of the total methane generation. For the landfill configuration without any cover, emissions to the atmosphere represent 66 % of the total generation.

ASSUNTO(S)

energia biogás aterro sanitário outros estimativa landfill gas biogas energy estimate

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