Estudo experimental da pirólise lenta da casca de arroz em reator de leito fixo
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Data
2018-02-20
Autores
Vieira, Fábio Roberto
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Universidade Estadual Paulista (Unesp)
Resumo
Nessa dissertação é investigada o aproveitamento energético da casca de arroz pela aplicação do processo de pirólise lenta em um reator de leito fixo, o qual foi projetado e construído para realização de trabalho. É estudada a influência dos parâmetros do processo nas características do biochar obtido a partir da casca de arroz, com o objetivo avaliar a sua potencialidade na geração de energia. Para tal foi realizada caracterizações físico-química da casca de arroz in natura e do biochar obtido, aplicando-se diversas técnicas de análise, além da avaliação da eficiência energética. As análises foram estudadas a fim de determinar as condições experimentais que favorecem as características do biochar, tais como poder calorífico superior (PCS) e concentração de carbono fixo, e também o rendimento na produção do mesmo. Foi utilizado um planejamento experimental, conforme metodologia de Taguchi, utilizando-se uma matriz L9 e variando-se os parâmetros que influenciam na pirólise, sendo eles a taxa de aquecimento (β) 5, 10 e 20 ºC/min, temperatura (T) de 300, 400 e 500 ºC, tempo de residência (t) de 3600, 5400 e 7200 s e massa da biomassa in natura (m) de 125, 250 e 500 g. Os resultados indicaram que para os diferentes parâmetros estudados, o maior rendimento de biochar (37,71%) foi observado na condição experimental realizada no teste 7, sendo adotado β=20 ºC/min, T=300 ºC, t=5400 s, e m=500 g. O teste 6 apresentou o maior PCS, 49,05% maior que o da casca de arroz in natura, sendo adotado β=10 ºC/min, T=500 ºC, t=5400 s e m=125 g. Na condição de maior concentração de carbono fixo, o teste 3 apresentou melhor resultado (60,10 %), no qual foi adotado β=5 ºC/min, T=500 ºC, t=7200 s e m=500 g. A ANOVA foi aplicada para analisar a variância do processo, sendo que a temperatura foi o parâmetro de maior influência no processo. Também foram determinadas as condições de melhor ajuste para otimização do processo para maior rendimento na produção de biochar (β= 20 ºC/min, T=300 ºC, t=3600 s e m=500 g), para maior concentração de carbono fixo no biochar (β=5 ºC/min, T=500 ºC, t=7200 s e , m=250 g) e para obtenção de biochar com maior PCS (β=10 ºC/min, T=500 ºC, t=3600 s e m=125 g). A avaliação energética mostrou que, tecnicamente, há um ganho energético na aplicação da pirólise lenta da casca de arroz.
In this dissertation is investigated the utilization of the rice husk means slow pyrolysis process in a fixed bed reactor, which was designed and built to perform work. The influence of the process parameters on the characteristics of the biochar obtained from the rice husk is studied, with the objective of evaluating its potential in the energy. For this purpose, physicalchemical characterization of the in natura rice husk and the biochar obtained were performed, applying several analysis techniques, as well as the energy efficiency assessment. The analyzes were studied in order to determine the experimental conditions favoring the biochar characteristics, such as higher heat value (HHV) and fixed carbon concentration, as well as the yield in the production of the same. An experimental design was used, according to Taguchi's methodology, using a L9 matrix and varying the parameters that influence pyrolysis, being the heating rate (β) 5, 10 and 20 ºC / min, temperature (T) of 300, 400 and 500 ° C, residence time (t) of 3600, 5400 and 7200 if mass of the in natura biomass (m) of 125, 250 and 500 g. The results indicated that the highest biochar yield (37.71%) was observed in the experimental condition performed in test 7, using β = 20 ºC / min, T = 300 ºC, t = 5400 s, in = 500 g. Test 6 showed the highest HHV, 49.05% higher than in natura rice husk, being adopted β = 10 ºC / min, T = 500 ºC, t = 5400 s and m = 125 g. In the condition of higher fixed carbon concentration, test 3 presented the best result (60.10%), in which β = 5 ° C / min, T = 500 ° C, t = 7200 s and m = 500 g. ANOVA was applied to analyze the process variance, with temperature being the parameter of greatest influence in the process. It was also determined the conditions of better adjustment for process optimization for higher yield of biochar (β = 20 ºC / min, T = 300 ºC, t = 3600 m = 500 g) for higher fixed carbon concentration in biochar (β = 10 °C/min, T = 500 °C, t = 7200 s, m = 250 g) and to obtain biochar with higher HHV). The energy evaluation showed that, technically, there is an energetic gain in the application of the slow pyrolysis of the rice husk.
In this dissertation is investigated the utilization of the rice husk means slow pyrolysis process in a fixed bed reactor, which was designed and built to perform work. The influence of the process parameters on the characteristics of the biochar obtained from the rice husk is studied, with the objective of evaluating its potential in the energy. For this purpose, physicalchemical characterization of the in natura rice husk and the biochar obtained were performed, applying several analysis techniques, as well as the energy efficiency assessment. The analyzes were studied in order to determine the experimental conditions favoring the biochar characteristics, such as higher heat value (HHV) and fixed carbon concentration, as well as the yield in the production of the same. An experimental design was used, according to Taguchi's methodology, using a L9 matrix and varying the parameters that influence pyrolysis, being the heating rate (β) 5, 10 and 20 ºC / min, temperature (T) of 300, 400 and 500 ° C, residence time (t) of 3600, 5400 and 7200 if mass of the in natura biomass (m) of 125, 250 and 500 g. The results indicated that the highest biochar yield (37.71%) was observed in the experimental condition performed in test 7, using β = 20 ºC / min, T = 300 ºC, t = 5400 s, in = 500 g. Test 6 showed the highest HHV, 49.05% higher than in natura rice husk, being adopted β = 10 ºC / min, T = 500 ºC, t = 5400 s and m = 125 g. In the condition of higher fixed carbon concentration, test 3 presented the best result (60.10%), in which β = 5 ° C / min, T = 500 ° C, t = 7200 s and m = 500 g. ANOVA was applied to analyze the process variance, with temperature being the parameter of greatest influence in the process. It was also determined the conditions of better adjustment for process optimization for higher yield of biochar (β = 20 ºC / min, T = 300 ºC, t = 3600 m = 500 g) for higher fixed carbon concentration in biochar (β = 10 °C/min, T = 500 °C, t = 7200 s, m = 250 g) and to obtain biochar with higher HHV). The energy evaluation showed that, technically, there is an energetic gain in the application of the slow pyrolysis of the rice husk.
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Palavras-chave
Pirólise lenta, Biochar, Casca de arroz, Reator de leito fixo, Biomassa, Slow pyrolysis, Rice husk, Fixed Bed Reactor, Biomass, Biocombustíveis