Análise da emissão de CO2 e cadeia de valor do uso de biomassa florestal como combustível em pequenas caldeiras a vapor na região Sul do Brasil

Abstract

Firewood is an important source of energy because it demands easy storage, a relatively low cost and its exploitation may be done with little processing. However, incomplete combustion of firewood produces a number of pollutants, including some fuels, such as carbon monoxide and other hydrocarbons, as well as components that participate in the mechanism of radiation heat transfer, such as carbon dioxide and water vapor. The boiler is a widely used system for the generation of energy, being also responsible for emissions of polluting gases. Therefore, the optimization and analysis of the feasibility of implementing the processes are of fundamental importance. Thus, the main objective of this work is to analyze the process of energy generation from the burning of wood in a boiler of the Santa Maria garrison in terms of emissions, energy use and costs. The methodological approach contemplates a case study of quantitative character with information obtained experimentally and in the literature. In addition, an analysis of the uncertainties of experimental measurements associated with volume, temperature and incomplete combustion was performed. The total emissions reached 36,3 tCO2e, and the equivalent of 98,07% can be sequestered by the tree. The costs related to the boiler are 43,856 R$/year, of which 30% was due to the acquisition of firewood. The results show that the recirculation case, for 20%, and the regenerative case presented savings of 0.98% and 1.79%, respectively. According to the financial parameters, the regenerative case was considered feasible and the recirculation case was feasible from 5% gas return, considering Selic equal to 7% as the minimum attractiveness rate. The results presented indicate the possibility of fuel economy and reduction in pollutant emissions.