Produção de biogás a partir de resíduos da produção de biodiesel de óleo e gordura residual
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Data
2021-05-21
Autores
Emidio, Camile Maria Pedrosa de Oliveira
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os combustíveis fósseis causam grandes impactos ambientais além de serem obtidos a partir de recursos não renováveis. Os biocombustíveis são uma solução a essa problemática. Um biocombustível já desenvolvido é o biodiesel, que pode ser obtido a partir de óleo de gordura residual (OGR). No processo de produção de biodiesel de OGR, são gerados dois resíduos, os restos alimentares e a glicerina, ambos com baixo valor de mercado que demanda a realização de estudos sobre a destinação desses resíduos. Uma alternativa é a produção de biogás. O biogás, composto por 50 a 70% de metano. No presente trabalho foi proposta a utilização desses dois resíduos para a produção de biogás. Inicialmente foi realizada uma caracterização dos resíduos para que assim fosse possível a determinação das condições experimentais. Em seguida, com agitação constante de 100 rpm, temperatura de 40 °C e tempo de 25 dias foram realizados dois experimentos para avaliar se a adição da glicerina seria benéfica, e como resultado foi obtido um aumento de 28,44% na produção de metano. A fim de avaliar as variáveis: tempo, porcentagem de glicerina a ser inserida no meio e pH, foi realizado um planejamento experimental 2³ com pontos centrais e axiais possibilitando a investigação para se obter o ponto ótimo de produção de metano e as variáveis que influenciam o processo. Utilizando o delineamento proposto, determinaram-se as variáveis estaticamente significativas, sendo estas o tempo e a porcentagem de glicerina no meio, além da definição do ponto ótimo de produção de metano, que correspondeu a um tempo de 30,4 dias e porcentagem de glicerina no meio de 3,36%. Com as condições ótimas obteve-se uma produção de 172,02 mL com 66,38 % de CH4 e redução da matéria orgânica (DQO) de 82,6%. Extrapolando para escala piloto com o volume total de 1000L, sendo 500L para headspace e utilizando as condições ótimas, a produção anual de metano seria de 8855,57L. A partir de uma análise econômica para a planta industrial pelos critérios Valor Presente Líquido(VPL), PayBack e Taxa Interna de Retorno(TIR), foi obtido respectivamente, os valores de R$ 2.145.168,49, 3,79 anos e 19%, demonstrando ser favorável a produção de biogás utilizando os resíduos da fábrica de biodiesel.
The fossil fuels have several environmental impacts, in addition to being obtained from non-renewable resources. Thus, the use of biofuels becomes more interesting, with emphasis on biodiesel, which can be obtained from residual fat oil (OGR). In the OGR biodiesel production process, two residues are generated, food waste and glycerin, both with low market value, which requires studies on the destination of these residues, a profitable possibility is the production of biogas. Biogas, composed of 50 to 70% methane, is a biofuel with market value. In the present work it was proposed to use these two residues for the production of biogas. Initially, a characterization of the residues was carried out so that it was possible to determine the experimental conditions. Then, with constant agitation of 100 rpm, temperature of 40 ° C and retention time of 25 days, two experiments were carried out to prove that the addition of glycerin in the medium would be beneficial, and as a result we obtained an increase of 28.44% in methane production. In order to evaluate the variables: retention time, percentage of glycerin to be inserted in the medium and pH, an experimental plan 23 was carried out with central and axial points, enabling the investigation to obtain the optimum point of methane production and the variables that influence the process. Using the proposed design, the statically significant variables were determined, these being the retention time and the percentage of glycerin in the medium, in addition to determining the optimum point of methane production that corresponds to a retention time of 30.4 days and percentage of glycerin in the middle of 3.36. With the optimum conditions, a production of 172.02 mL was obtained with 66.38% and a reduction in organic matter of 82.6%. Extrapolating to a pilot scale, the annual methane production would be 8855.57L. Based on an economic analysis for the industrial plant using the VPL, PayBack and TIR, it found the values of R$ 2,145,168.49, 3.79 years and 19%, respectively, showing that biogas production using the waste from the biodiesel is a good choice.
The fossil fuels have several environmental impacts, in addition to being obtained from non-renewable resources. Thus, the use of biofuels becomes more interesting, with emphasis on biodiesel, which can be obtained from residual fat oil (OGR). In the OGR biodiesel production process, two residues are generated, food waste and glycerin, both with low market value, which requires studies on the destination of these residues, a profitable possibility is the production of biogas. Biogas, composed of 50 to 70% methane, is a biofuel with market value. In the present work it was proposed to use these two residues for the production of biogas. Initially, a characterization of the residues was carried out so that it was possible to determine the experimental conditions. Then, with constant agitation of 100 rpm, temperature of 40 ° C and retention time of 25 days, two experiments were carried out to prove that the addition of glycerin in the medium would be beneficial, and as a result we obtained an increase of 28.44% in methane production. In order to evaluate the variables: retention time, percentage of glycerin to be inserted in the medium and pH, an experimental plan 23 was carried out with central and axial points, enabling the investigation to obtain the optimum point of methane production and the variables that influence the process. Using the proposed design, the statically significant variables were determined, these being the retention time and the percentage of glycerin in the medium, in addition to determining the optimum point of methane production that corresponds to a retention time of 30.4 days and percentage of glycerin in the middle of 3.36. With the optimum conditions, a production of 172.02 mL was obtained with 66.38% and a reduction in organic matter of 82.6%. Extrapolating to a pilot scale, the annual methane production would be 8855.57L. Based on an economic analysis for the industrial plant using the VPL, PayBack and TIR, it found the values of R$ 2,145,168.49, 3.79 years and 19%, respectively, showing that biogas production using the waste from the biodiesel is a good choice.
Descrição
Palavras-chave
Biodiesel, Resíduos Alimentares, Glicerina, Biogas