Prognóstico do coprocessamento de diferentes matrizes ambientais em consórcio para obtenção de um combustível sólido
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Data
2019-03-14
Autores
Nozela, Weverton Campos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O gerenciamento inadequado dos diversos tipos de resíduos sólidos pode causar grandes impactos ambientais e demandam um custo elevado para a correta disposição. Entretanto, alguns resíduos apresentam condições de reciclagem energética. Resíduos vegetais, como a cana de açúcar e palha do milho, e resíduos sanitários, como lodo de esgoto, que são geralmente chamados de biomassas podem produzir energia a partir de processos térmicos como a pirólise ou a torrefação. Atualmente, as biomassas correspondem a quarta maior fonte de energia da matriz mundial e a segunda no Brasil. O objetivo deste trabalho foi elaborar um prognóstico de aplicação energética a partir do coprocessamento, utilizando-se de técnicas de peletização e torrefação, com diferentes matrizes ambientais em consórcio, como o lodo de esgoto e poda urbana, para obtenção de um combustível sólido e renovável. As amostras deste trabalho foram coletadas das Estações de Tratamento de Esgoto (ETE) de Araraquara, Bueno e Monjolinho, além de resíduos de poda urbana. Após moagem criogênica, foram preparados consórcios 1:1 entre os lodos e a poda. Posteriormente, foi aplicado procedimento de peletização e torrefação. Por termogravimetria, foram determinadas Temperatura de Ignição, Análise Imediata e Estudo Cinético, onde foi utilizado o Método de Wanjun-Donghua modificado por Capela-Ribeiro para determinação dos parâmetros cinéticos, energia de ativação e lnA. Outros parâmetros como Poder Calorífico Superior (PCS) e Análise Elementar também foram estabelecidos, além de análises complementares como Higroscopia e Infravermelho. Os resultados indicaram que peletização reduziu o volume das amostras (45 a 67%), e apresentou menores temperaturas de ignição, entre 230 e 235 °C para os lodos e 222 e 245 °C para os consórcios. Já a torrefação reduziu as massas das amostras (22 a 44%) e o teor de umidade das amostras (2,28 a 5,10%). As amostras torrefadas apresentaram uma resistência em absorver umidade quando expostas em condições de temperatura de 25 °C e 70% de umidade relativa do ar, sendo que o ganho de massa nestas condições foi de 1,44 a 3,39%. Houve ainda um aumento no teor de carbono fixo nas amostras torrefadas, 35 a 51% nos lodos e de 72 a 124% nos consórcios. Este aumento impactou no aumento no PCS, sendo que para as amostras de poda urbana, o lodo e o consórcio de Bueno os PCS’s foram de 25,82 MJ kg-1, 18,22 MJ kg-1 e 19,66 MJ kg-1, respetivamente. A energia de ativação da reação de degradação térmica da matéria orgânica foi decrescente, principalmente nas amostras torrefadas, indicando autossuficiência energética após iniciar a reação. Foram observados Efeitos de Compensação Cinética e de Sinergismo em algumas amostras. Pelos dados expostos, as amostras podem ser armazenadas, transportadas e comercializadas mesmo em condições climáticas adversas. O consórcio de resíduos apresenta um valor agregado, uma vez que a disposição inadequada dos resíduos pode contribuir para a degradação ambiental e a utilização como combustível sólido é uma forma alternativa e inteligente de reduzir o consumo proveniente de fontes não renováveis e proporcionar um destino apropriado aos resíduos.
Inadequate management of the various types of solid waste can cause major environmental impacts and require a high cost for the correct disposal. However, some waste presents energy recycling conditions. Plant residues, such as sugarcane and corn husk, and sanitary waste, such as sewage sludge, which are generally called biomass can produce energy from thermal processes such as pyrolysis or torrefaction. Currently, biomass is the fourth largest energy source in the world matrix and the second in Brazil. The objective of this work was to elaborate a prognosis of energy application from the coprocessing, using pelletizing and torrefaction techniques, with different environmental matrices in consortium, such as sewage sludge and urban pruning, to obtain a solid and renewable fuel. The samples from this work were collected from the Sewage Treatment Plants (ETE) of Araraquara, Bueno and Monjolinho, as well as urban pruning waste. After cryogenic grinding, 1: 1 consortia were prepared between sludge and pruning. Subsequently, a pelletizing and torrefaction procedure was applied. By thermogravimetry, Ignition Temperature, Proximate Analysis and Kinetic Study were determined, where the Wanjun-Donghua method modified by Capela-Ribeiro was used to determine the kinetic parameters, activation energy and lnA. Other parameters such as Higher Heating Values (HHV) and Ultimate Analysis were also established, as well as complementary analyzes such as Hygroscopy and Infrared. The results indicated that pelletizing reduced sample volume (45-67%), and showed lower ignition temperatures, between 230 and 235 °C for sludge and 222 and 245 °C for consortia. Roasting reduced sample masses (22-44%) and the moisture content of the samples (2.28-5.10%). Torrefied samples had a resistance to moisture absorption when exposed to temperature conditions of 25 °C and 70% relative humidity, and the mass gain in these conditions was 1.44 to 3.39%. There was also an increase in the fixed carbon content in the torrefied samples, 35 to 51% in the sludge and 72 to 124% in the consortia. This increase had an impact on the increase in HHV, and for the urban pruning, sludge and consortia from Bueno the HHV were 25.82 MJ kg-1, 18.22 MJ kg-1 and 19.66 MJ kg-1, respectively. The activation energy of the thermal degradation reaction of the organic matter was decreasing, mainly in the roasted samples, indicating energy self-sufficiency after starting the reaction. Kinetic Compensation and Synergism Effects were observed in some samples. From the above data, the samples can be stored, transported and marketed even in adverse climatic conditions. The waste consortium has added value, as inadequate disposal of waste can contribute to environmental degradation and use as a solid fuel is an alternative and smart way to reduce consumption from non-renewable sources and to provide an appropriate waste destination.
Inadequate management of the various types of solid waste can cause major environmental impacts and require a high cost for the correct disposal. However, some waste presents energy recycling conditions. Plant residues, such as sugarcane and corn husk, and sanitary waste, such as sewage sludge, which are generally called biomass can produce energy from thermal processes such as pyrolysis or torrefaction. Currently, biomass is the fourth largest energy source in the world matrix and the second in Brazil. The objective of this work was to elaborate a prognosis of energy application from the coprocessing, using pelletizing and torrefaction techniques, with different environmental matrices in consortium, such as sewage sludge and urban pruning, to obtain a solid and renewable fuel. The samples from this work were collected from the Sewage Treatment Plants (ETE) of Araraquara, Bueno and Monjolinho, as well as urban pruning waste. After cryogenic grinding, 1: 1 consortia were prepared between sludge and pruning. Subsequently, a pelletizing and torrefaction procedure was applied. By thermogravimetry, Ignition Temperature, Proximate Analysis and Kinetic Study were determined, where the Wanjun-Donghua method modified by Capela-Ribeiro was used to determine the kinetic parameters, activation energy and lnA. Other parameters such as Higher Heating Values (HHV) and Ultimate Analysis were also established, as well as complementary analyzes such as Hygroscopy and Infrared. The results indicated that pelletizing reduced sample volume (45-67%), and showed lower ignition temperatures, between 230 and 235 °C for sludge and 222 and 245 °C for consortia. Roasting reduced sample masses (22-44%) and the moisture content of the samples (2.28-5.10%). Torrefied samples had a resistance to moisture absorption when exposed to temperature conditions of 25 °C and 70% relative humidity, and the mass gain in these conditions was 1.44 to 3.39%. There was also an increase in the fixed carbon content in the torrefied samples, 35 to 51% in the sludge and 72 to 124% in the consortia. This increase had an impact on the increase in HHV, and for the urban pruning, sludge and consortia from Bueno the HHV were 25.82 MJ kg-1, 18.22 MJ kg-1 and 19.66 MJ kg-1, respectively. The activation energy of the thermal degradation reaction of the organic matter was decreasing, mainly in the roasted samples, indicating energy self-sufficiency after starting the reaction. Kinetic Compensation and Synergism Effects were observed in some samples. From the above data, the samples can be stored, transported and marketed even in adverse climatic conditions. The waste consortium has added value, as inadequate disposal of waste can contribute to environmental degradation and use as a solid fuel is an alternative and smart way to reduce consumption from non-renewable sources and to provide an appropriate waste destination.
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Palavras-chave
Peletização, Pirólise, Biomassa, Lodo de esgoto, Combustíveis sólidos