Emissões De Gases Do Efeito Estufa Da Queima De Pellets De Madeira

Abstract

ResumoAs previsões indicam crescimento do uso da biomassa florestal como recurso energético nos próximos anos, sobretudo depois dos recentes acordos firmados pela Cúpula do Clima em Paris (COP21), que apontam a necessidade de substituir combustíveis fósseis por fontes renováveis e de baixas emissões de gases do efeito estufa (GEE). Há poucos estudos relacionando a combustão dos pellets de madeira com os limites dessas emissões estabelecidos para a biomassa florestal. Este estudo comparou as emissões da combustão dos pellets com os limites máximos estabelecidos na Resolução nº 436 do CONAMA. Utilizou-se quatro amostras de pellets de madeira e três biomassas florestais (casca de pinus, cavacos de pinus e serragem de eucalipto). Para a combustão foi utilizado um queimador de biomassa vegetal, com alimentação automática e consumo de 14 kg por hora. As análises das emissões foram realizadas com o analisador eletroquímico Unigas 3000 MKIII, que determinou a composição química dos gases da combustão. Os resultados mostraram que os pellets de madeira têm baixas emissões de CO, NO x e SO x . Assim, conclui-se que as biomassas florestais atendem aos limites de emissões gasosas estabelecidos pela legislação vigente, com exceção da serragem de eucalipto e a casca de pinus. Palavras-chave: Biomassa florestal; combustível sólido; cinzas; combustão; COP21. Abstract Emissions of greenhouse effect gases from wood pellets burning.Forecasts indicate the growth in use of forest biomass as the energy resource in the coming years, especially after the recent agreements reached at Paris Climate Summit -COP21, which imply the replacement of fossil fuels for renewable ones, with lowemission Greenhouse Gas -GHG. There are few studies relating the wood pellets combustion with the limits of these emissions established for forest biomass. This study compared the pellet combustion emissions with the maximum limits established in Resolution nº 436 of the National Council of Environment -CONAMA. Four samples of wood pellets and three forest biomasses (pine bark, pine chip and eucalyptus sawdust) were used. A vegetable biomass burner was used for combustion, with automatic feed and consumption of 14 kg per hour. Emissions analyzes were performed with the Unigas 3000 MKIII electrochemical analyzer, which determined the chemical composition of the combustion gases. The results showed that the wood pellets have low CO, NO x and SO x emissions. Thus, it can be concluded that these biomasses meet the gaseous emission limits established by the current legislation, except for eucalyptus sawdust and pine bark biomass. Keywords: Forest biomass; solid fuel; ashes; combustion; COP21. INTRODUÇÃOAs emissões de dióxido de carbono (CO 2 ), da queima de combustíveis fósseis, contribuiu com cerca de 78% do aumento dos gases do efeito estufa (GEE) no período de 1970 a 2010. Apesar de um número crescente de políticas de mitigação das mudanças climáticas, essas emissões cresceram 2,2% ao ano, entre 2000 e 2010. Nos trinta anos anteriores a este período, a velocida...

Combustion of pellets produced from corn straw and cashew nut shell in residential and industrial scenarios: Chemical, thermal and emission analyses

“…The fixed carbon content (%FC) showed mean values of 17.99 ± 1.00, 13.48 ± 0.59, 11.75 ± 0.46 and 9.57 ± 1.25% for CSP, CSGP, CNSP and CNSGP, respectively. Values around 15% had been found in a previous study on wood pellets (Garcia et al, 2017). International standards do not show consensus or do not present values for the fixed carbon content.…”

“…The immediate aim of the chemical analyses was to assess moisture (% U ), volatile materials (% V ), ash (% C ) and fixed carbon (%FC) present in the biomasses, for energy purposes (Garcia et al, 2017). Moisture content was calculated according to Garciaet al (2017).…”

“…The immediate aim of the chemical analyses was to assess moisture (% U ), volatile materials (% V ), ash (% C ) and fixed carbon (%FC) present in the biomasses, for energy purposes (Garcia et al, 2017). Moisture content was calculated according to Garciaet al (2017). In summary, three samples of 1.00 ± 0.05 g of each type of pellet (CSP and CNSP) were placed in a crucible and weighed on an analytical balance, then immediately heated in a thermal oven at 105°C for 4 hours and then cooled in a desiccator until room temperature, before being weighed again.…”

Combustion of pellets produced from the powders of coconut and cashew nut shells: Chemical, thermal and emission analyses

“…The immediate aim of the chemical analyses was to assess the moisture content ( % U ), volatile material ( % V ), ash ( % C ) and fixed carbon ( % F C ) present in the biomass, for energy purposes (Garcia et al, 2017). Chemical analysis procedures to determine moisture content were carried out according to the norms of the Brazilian Association of Technical Standards (ABNT NBR/9656, 1986).…”

“…Chemical analysis procedures to determine moisture content were carried out according to the norms of the Brazilian Association of Technical Standards (ABNT NBR/9656, 1986). Moisture content was calculated according to Garcia et al (2017). In summary, three samples of 1.00 ± 0.05 g of each type of pellet (CSP and CNSP) were placed in a crucible and weighed on an analytical balance, then immediately heated in a thermal oven at 105°C for 4 h and then cooled in a desiccator until room temperature, before being weighed again.…”