Caracterização e avaliação do resíduo de cultivo do cogumelo shiitake - Lentinula edodes - para fins bioenergéticos
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Data
2016-08-31
Autores
Viotto, Renata Silva [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os atuais padrões mundiais de consumo energético estão baseados na utilização de combustíveis fósseis, os quais, além de serem não renováveis, geram diversos problemas ambientais. Nos últimos anos houve um aumento na busca por fontes energéticas alternativas e mais sustentáveis, como as biomassas provenientes de resíduos agroindustriais, as quais podem apresentar grande potencial energético por área e baixos impactos ambientais. Com o intuito de minimizar os problemas ambientais relacionados à geração e descarte de resíduos provenientes das atividades de cultivo de cogumelos, esse estudo teve como objetivo avaliar o potencial bioenergético do resíduo de cultivo de shiitake (RCS) seco e por meio de sua conversão termoquímica pelo processo de pirólise em três temperaturas diferentes (350°C, 450°C e 550°C). Mediante às análises, o biocarvão de 350°C (BC350) foi considerado com o maior potencial energético devido à menor quantidade de cinzas e maiores quantidades de materiais voláteis, carbono fixo, poder calorífico, rendimento gravimétrico e fator de rendimento gravimétrico. As análises químicas e físicas revelaram que o RCS seco apresenta uma natureza bastante complexa, característica comumente encontrada em materiais de origem lignocelulósica. As análises termogravimétricas foram realizadas em três rampas de aquecimento, 10°C/min, 15°C/min e 20°C/min, em atmosfera oxidante e inerte. Foram identificadas etapas de conversão referentes à perda de água e degradação de hemicelulose, celulose e lignina. O estudo cinético foi realizado com o método não isotérmico e não isoconversional de Kissinger. As energias de ativação obtidas foram de 110,3 kJ/mol e 136 kJ/mol para o RCS seco e BC350, respectivamente, e encontraram-se dentro do intervalo obtido para outras biomassas. O RCS apresentou características que permitiram concluir que esse resíduo possui um grande valor para ser utilizado como um potencial recurso para a geração de bioenergia. Potencial que pode ser melhorado através do processo de pirólise a 350°C.
Current global patterns of energy consumption are based on the use of fossil fuels, which are not only non-renewable resources, but also generate vast environmental problems. Recent years have witnessed an increasing search for alternative, more sustainable, energy sources, such as biomasses originated from agroindustrial residues, a material that may present great energetic potential per area and minor environmental impacts. Aiming at minimizing environmental impacts related with the generation and discard of mushroom cultivation residues, the present study intended to evaluate the bioenergetic potential of the spent shiitake substrate (SSS), both in its dry form and after its thermochemical conversion by a pyrolysis process in 3 different temperatures (350°C, 450°C e 550°C). Further analyses founded the consideration that the 350°C biochar (BC350) was that with the greatest energetic potential, due to its reduced ash amounts and higher volatile amounts, fixed carbon, heat value, gravimetric yield and gravimetric yield factor. Chemical and physical analyses revealed that the dry SSS possesses a highly complex nature, characteristics commonly found in lignocellulosic materials. Thermogravimetric analyses were performed in 3 heating rates, 10°C/min, 15°C/min and 20°C/min in oxidizing and inert atmospheres. Conversion steps related with water loss and degradation of hemicellulose, cellulose and lignin have been identified. The kinetic study was carried out by non-isothermal and non-isoconversional Kissinger method. The activation energies obtained were of 110.3 kJ mol-1 and 136 kJ mol-1 for the SSS and BC350, respectively and are within the range found for other biomasses. The SSS presented features that allow the conclusion that such residue possesses great potential for bioenergy generation applications, potential which may be improved by means of a pyrolysis at 350°C.
Current global patterns of energy consumption are based on the use of fossil fuels, which are not only non-renewable resources, but also generate vast environmental problems. Recent years have witnessed an increasing search for alternative, more sustainable, energy sources, such as biomasses originated from agroindustrial residues, a material that may present great energetic potential per area and minor environmental impacts. Aiming at minimizing environmental impacts related with the generation and discard of mushroom cultivation residues, the present study intended to evaluate the bioenergetic potential of the spent shiitake substrate (SSS), both in its dry form and after its thermochemical conversion by a pyrolysis process in 3 different temperatures (350°C, 450°C e 550°C). Further analyses founded the consideration that the 350°C biochar (BC350) was that with the greatest energetic potential, due to its reduced ash amounts and higher volatile amounts, fixed carbon, heat value, gravimetric yield and gravimetric yield factor. Chemical and physical analyses revealed that the dry SSS possesses a highly complex nature, characteristics commonly found in lignocellulosic materials. Thermogravimetric analyses were performed in 3 heating rates, 10°C/min, 15°C/min and 20°C/min in oxidizing and inert atmospheres. Conversion steps related with water loss and degradation of hemicellulose, cellulose and lignin have been identified. The kinetic study was carried out by non-isothermal and non-isoconversional Kissinger method. The activation energies obtained were of 110.3 kJ mol-1 and 136 kJ mol-1 for the SSS and BC350, respectively and are within the range found for other biomasses. The SSS presented features that allow the conclusion that such residue possesses great potential for bioenergy generation applications, potential which may be improved by means of a pyrolysis at 350°C.
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Palavras-chave
Resíduo de cultivo de shiitake, Biomassa, Bioenergia, Biocarvão, Spent shiitake substrate, Biomass, Bioenergy, Biochar