Técnicas multivariadas (HCA e PCA) aplicadas na avaliação de biomassas vegetais para produção de pellets
Carregando...
Arquivos
Data
2017-02-07
Autores
Garcia, Dorival Pinheiro [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
As previsões indicam crescimento da demanda por pellets de biomassa nos próximos anos, sobretudo depois dos recentes acordos firmados pela Conferência do Clima em Paris (COP21), que aponta a necessidade de substituir combustíveis fósseis por recursos energéticos com baixas emissões de carbono. Países desenvolvidos pesquisam plantas de ciclo curto e alto rendimento de massa seca que possam suprir essa necessidade por energia limpa e renovável. No Brasil, começam a se desenvolver culturas energéticas como o bambu, cana-energia, sorgo e capim-elefante, que são especialmente dedicados à geração de energia termoelétrica. Porém, pouco se sabe sobre a viabilidade técnica da produção de pellets com essas biomassas. Este estudo analisou as características físicas (densidade a granel, teor de umidade e durabilidade mecânica), químicas (CHNS/O, carbono fixo, voláteis, cinzas, extrativos, lignina e holocelulose) e térmicas (poder calorífico superior e inferior, densidade energética) de nove amostras de pellets, sendo cinco de biomassa florestal e quatro gramíneas. Objetivou-se determinar qual biomassa vegetal apresenta as melhores características bioenergéticas para a produção de pellets e as técnicas multivariadas de agrupamento hierárquico (HCA) e dos componentes principais (PCA) foram empregadas nessa avaliação. Os resultados, que foram comparados com os padrões estabelecidos na norma internacional ISO 17225, mostraram que os pellets de biomassa florestal apresentaram características bioenergéticas mais eficazes do que os pellets de gramíneas. Assim, concluiu-se que o pinus apresentou o melhor desempenho global para a produção de biocombustíveis sólidos na forma de pellets, com favoráveis teores de cinzas, densidade energética, poder calorífico e volume específico.
A biomass growth pellets demand is expected in the coming years, especially after the recent agreements signed by the Climate Conference in Paris (COP 21), which indicates the need to replace fossil fuels for energy sources with low carbon emissions. Short-cycle plants with dry mass high-output production is the aim of developed countries researches, in order to meet the need for clean and renewable energy. Energy crops like bamboo, energy cane, sorghum and elephant grass has begun in Brazil, which are especially applied to thermoelectric power generation. Nevertheless, there is little awareness about the technical feasibility of pellet production using these biomasses. This study examined the physical (bulk density, moisture content, mechanical durability), chemical (CHNS/O, fixed carbon, volatile, ash, extractive, lignin, holocellulose) and thermal characteristics (high and lower calorific value, energy density) of nine pellets samples. Five of them were plant biomass – from forest and four grass species. The purpose to determine which plant biomass has the best bioenergetic characteristics for the production of pellets and multivariate techniques of hierarchical Clustering (HAC) and the main components (PCA) were used in this evaluation. The results, compared with the standards set by ISO 17225, showed that forest biomass pellets presented more efficient bioenergetic characteristics than grass pellets. Thus, it was concluded that the Pinus woody biomass showed the best overall performance for the production of solid biofuels in pellets form, with favorable ash content, energy density, calorific value and specific volume.
A biomass growth pellets demand is expected in the coming years, especially after the recent agreements signed by the Climate Conference in Paris (COP 21), which indicates the need to replace fossil fuels for energy sources with low carbon emissions. Short-cycle plants with dry mass high-output production is the aim of developed countries researches, in order to meet the need for clean and renewable energy. Energy crops like bamboo, energy cane, sorghum and elephant grass has begun in Brazil, which are especially applied to thermoelectric power generation. Nevertheless, there is little awareness about the technical feasibility of pellet production using these biomasses. This study examined the physical (bulk density, moisture content, mechanical durability), chemical (CHNS/O, fixed carbon, volatile, ash, extractive, lignin, holocellulose) and thermal characteristics (high and lower calorific value, energy density) of nine pellets samples. Five of them were plant biomass – from forest and four grass species. The purpose to determine which plant biomass has the best bioenergetic characteristics for the production of pellets and multivariate techniques of hierarchical Clustering (HAC) and the main components (PCA) were used in this evaluation. The results, compared with the standards set by ISO 17225, showed that forest biomass pellets presented more efficient bioenergetic characteristics than grass pellets. Thus, it was concluded that the Pinus woody biomass showed the best overall performance for the production of solid biofuels in pellets form, with favorable ash content, energy density, calorific value and specific volume.
Descrição
Palavras-chave
Biomassa vegetal, Biocombustíveis, ISO 17225, Pellets de madeira