Energetic valorization of biogas. A comparison between centralized and decentralized approach

[EN] In the present manuscript, the energy efficiency and economic feasibility of different digestion configurations were evaluated by considering a double turbocharged engine, Jenbacher type JGS 320 GS-BL. Scenarios considered a single farm producing the biogas needed to run the engine (Scenario 1). The second scenario assumed a centralized system treating manure from the surrounding farms (Scenario 2). The third scenario considered partial decentralization with farms treating locally produced wastes, and biogas being transported and valorized in a centralized engine (Scenario 3). Centralized valorization showed the best results. However, this scheme is inappropriate due to the size of the farm needed to support this configuration. The transport of wastes to a centralized treatment unit showed similar efficiency values but the economic feasibility was adversely affected. The worst performance was found for the decentralized configuration with efficiency in the range of 39–43%, much lower values than those obtained from previous cases (58%) with null economic feasibility due to the high costs associated with the transport of biogas either by truck or through a piping system.S

Biochar and Energy Production: Valorizing Swine Manure through Coupling Co-Digestion and Pyrolysis

[EN] naerobic digestion is an established technological option for the treatment of agricultural residues and livestock wastes beneficially producing renewable energy and digestate as biofertilizer. This technology also has significant potential for becoming an essential component of biorefineries for valorizing lignocellulosic biomass due to its great versatility in assimilating a wide spectrum of carbonaceous materials. The integration of anaerobic digestion and pyrolysis of its digestates for enhanced waste treatment was studied. A theoretical analysis was performed for three scenarios based on the thermal needs of the process: The treatment of swine manure (scenario 1), co-digestion with crop wastes (scenario 2), and addition of residual glycerine (scenario 3). The selected plant design basis was to produce biochar and electricity via combined heat and power units. For electricity production, the best performing scenario was scenario 3 (producing three times more electricity than scenario 1), with scenario 2 resulting in the highest production of biochar (double the biochar production and 1.7 times more electricity than scenario 1), but being highly penalized by the great thermal demand associated with digestate dewatering. Sensitivity analysis was performed using a central composite design, predominantly to evaluate the bio-oil yield and its high heating value, as well as digestate dewatering. Results demonstrated the effect of these parameters on electricity production and on the global thermal demand of the plant. The main significant factor was the solid content attained in the dewatering process, which excessively penalized the global process for values lower than 25% TS.SIThis research was funded by FGULEM, grant number NT55-2018. Judith González would like to thank the Junta de Castilla y León (Consejería de Educación) fellowship, Orden EDU/1100/2017, co-financed by the European Social Fund

Biological treatments of cheese whey for biogas and hydrogen production. Review

A industria leitera caracteriza-se por uma elevada geração de soro de leite, um subproduto do processo de fabricação do queijo, com um elevado conteúdo em materia orgánica na forma de lactose, proteínas e outros compostos a partir da leite. Por esta razão, considera-se um material suscetível de ser valorizado mediante a recuperação destes produtos para posteriores aplicações alimentárias, farmacéuticas a para a obtenção de biocombustíveis. Uma das alternativas para proveitar a energía é a aplicação de tratamentos anaeróbios, sendo uma das tecnologias mais usadas com os residuos sólidos, líquidos , e também as águas residuais. O lacstosuero é considerado um substrato com um elevado potencial para a geração de biogás, é por isso que têm sido aplicado em diferentes estudos. No entanto, apresenta difculdades devido à sua tendência para a acidifcação e a limitação de nutrientes que poden causar falhas durante o processo. Por esta razão, temos promovido outras alternativas, tais como os processos de co-digestão com outros materiais ou a fermentação escura orientada para a produção de hidrogénio. Este artigo centra-se numa revisão blibliográfca dos principáis trabalhos que têm sido desenvolvidos aplicando os processos acima descritos, com uma apresentação dos resultados mais relevantes obtidos considerando a infuência das condições de operação e os fatores que afetam à produção.Dairy industry is characterized by high generation of cheese whey, a byproduct from cheese factories with a high organic matter content in the form of lactose, proteins and other compounds coming from processed milk. If it is not properly disposed it might favour serious environmental pollution problems. However, it is possible the application of recovery technologies in order to obtain its main compounds for further applications such as food or pharmaceutical industry, and for obtaining biofuels. Nowadays, biofuels are an important source of renewable energy as potential future alternative for fossil fuels. For this reason, energetic valorisation of cheese whey has become an interensting alternative. Anaerobic digestion is considered one of the most used technologies in wastewater and solid waste treatments. Several studies have been conducted with cheese whey as a suitable substrate with a considerable biogas potential production. However, it presents some disadvantages due to the rapid acidifcation tendency and nutrient content limitations that might favor failures in the process. For this reason, alternatives like anaerobic co-digestion with other substrates or dark fermentation for hydrogen production have been proposed. This paper intends to review the main works developed applying the mentioned technologies along with its most relevant results considering operation conditions infuence and the environmental factors affecting production.La industria láctea se caracteriza por generar lactosuero como subproducto del proceso de elaboración del queso. El lactosuero presenta un elevado contenido en materia orgánica en forma de lactosa, proteínas y otros compuestos procedentes de la leche. Su vertido incontrolado puede ocasionar problemas de contaminación con un grave impacto ambiental. Sin embargo, la recuperación de algunos componentes del lactosuero permite valorizar este subproducto, encontrando aplicación en la industria alimentaria, farmacéutica y recientemente en la conversión del lactosuero para la producción de biocombustibles. Actualmente, los biocombustibles son una fuente potencial de energía renovable con un papel importante como posibles sustitutos de los combustibles fósiles. Por este motivo, la opción de gestionar el lactosuero mediante una valorización energética ha adquirido gran interés durante los últimos años. Entre las alternativas disponibles de aprovechamiento energético, se encuentra la digestión anaerobia, la cual es una de las tecnologías más empleadas para el tratamiento de diverso tipo de residuos. En el caso del lactosuero, se han desarrollado múltiples trabajos en los que se han utilizado diferentes configuraciones y condiciones de operación con el objetivo de mejorar el funcionamiento del proceso. Gracias a estos trabajos se han podido identificar algunos de los factores que limitan su aplicación como son: la tendencia a la acidificación o la limitación de nutrientes. Por este motivo se han promovido otras alternativas como son los procesos de co-digestión con varios materiales o la fermentación oscura. El objetivo de este artículo es la realización de una revisión bibliográfica de los principales trabajos realizados en los que se contemplan los procesos biológicos anteriormente mencionados. Se presentan los resultados más relevantes, así como la influencia de las condiciones de operación y los factores que afectan a la producción de biogás

Valorización energética de residuos: análisis de la combustión conjunta de biogás y gases de pirólisis (piro-BIOGÁS)

Pyro-BIOGAS is a project that proposes combined waste management applying anaerobic digestion and pyrolysis processes for recove-ring energy. This project aims to encourage the use of renewable resources that are currently considered as waste for energy production. In order to attain the main objectives proposed, it was performed an evaluation of biogas production yields of different waste materials, along with the analysis of thermal and kinetic properties during pyrolysis of digested material. With this information, energy efficiency and economic feasibility of a combined process of anaerobic digestion of swine manure and pyrolysis of the digestate with lignocellulosic material was studied. On the other hand, burning characteristics of the gas thus obtained were evaluated. Through the combined use of biogas and pyrolysis gases, self-sufficient systems can be achieved, with extra energy production to be used for other purposes in the installation. It was observed, that burning characteristics, such us flame speed and temperature were affected by H2 and CO2 content.En el proyecto piro-BIOGÁS se ha planteado el estudio del aprovechamiento energético de los gases combustibles generados en un proceso conjunto de digestión anaerobia y pirólisis del material digerido. Con esta propuesta se pretende incentivar el uso de recursos renovables, que en la actualidad se consideran residuos, para la producción de energía. Con la finalidad de cumplir los objetivos propuestos, se han evaluado los rendimientos de producción de biogás de diferentes residuos, junto con las propiedades térmicas y cinéticas de la pirólisis del material digerido. A partir de los datos obtenidos, se ha planteado el balance energético y el estudio de viabilidad económica en una planta de digestión anaerobia para el tratamiento de purín, integrando una unidad de pirólisis para el digerido, mezclado con material lignocelulósico. Por otro lado, también se ha estudiado el comportamiento durante la combustión de diferentes mezclas biogás-gas pirólisis. Mediante el análisis de los rendimientos energéticos y la evaluación económica, se observó que el uso combinado del biogás y de los gases de pirólisis permite plantear instalaciones autosostenibles energéticamente, con un excedente de energía que puede cubrir otro tipo de necesidades térmicas en la planta. Se ha comprobado que el comportamiento de la combustión de las mezclas biogás-gas pirólisis está condicionado por el contenido de CO2 y H2, afectando tanto a la velocidad de propagación como a la temperatura de la llama

Biological treatments of cheese whey for biogas and hydrogen production. Review

A industria leitera caracteriza-se por uma elevada geração de soro de leite, um subproduto do processo de fabricação do queijo, com um elevado conteúdo em materia orgánica na forma de lactose, proteínas e outros compostos a partir da leite. Por esta razão, considera-se um material suscetível de ser valorizado mediante a recuperação destes produtos para posteriores aplicações alimentárias, farmacéuticas a para a obtenção de biocombustíveis. Uma das alternativas para proveitar a energía é a aplicação de tratamentos anaeróbios, sendo uma das tecnologias mais usadas com os residuos sólidos, líquidos , e também as águas residuais. O lacstosuero é considerado um substrato com um elevado potencial para a geração de biogás, é por isso que têm sido aplicado em diferentes estudos. No entanto, apresenta difculdades devido à sua tendência para a acidifcação e a limitação de nutrientes que poden causar falhas durante o processo. Por esta razão, temos promovido outras alternativas, tais como os processos de co-digestão com outros materiais ou a fermentação escura orientada para a produção de hidrogénio. Este artigo centra-se numa revisão blibliográfca dos principáis trabalhos que têm sido desenvolvidos aplicando os processos acima descritos, com uma apresentação dos resultados mais relevantes obtidos considerando a infuência das condições de operação e os fatores que afetam à produção.Dairy industry is characterized by high generation of cheese whey, a byproduct from cheese factories with a high organic matter content in the form of lactose, proteins and other compounds coming from processed milk. If it is not properly disposed it might favour serious environmental pollution problems. However, it is possible the application of recovery technologies in order to obtain its main compounds for further applications such as food or pharmaceutical industry, and for obtaining biofuels. Nowadays, biofuels are an important source of renewable energy as potential future alternative for fossil fuels. For this reason, energetic valorisation of cheese whey has become an interensting alternative. Anaerobic digestion is considered one of the most used technologies in wastewater and solid waste treatments. Several studies have been conducted with cheese whey as a suitable substrate with a considerable biogas potential production. However, it presents some disadvantages due to the rapid acidifcation tendency and nutrient content limitations that might favor failures in the process. For this reason, alternatives like anaerobic co-digestion with other substrates or dark fermentation for hydrogen production have been proposed. This paper intends to review the main works developed applying the mentioned technologies along with its most relevant results considering operation conditions infuence and the environmental factors affecting production.La industria láctea se caracteriza por generar lactosuero como subproducto del proceso de elaboración del queso. El lactosuero presenta un elevado contenido en materia orgánica en forma de lactosa, proteínas y otros compuestos procedentes de la leche. Su vertido incontrolado puede ocasionar problemas de contaminación con un grave impacto ambiental. Sin embargo, la recuperación de algunos componentes del lactosuero permite valorizar este subproducto, encontrando aplicación en la industria alimentaria, farmacéutica y recientemente en la conversión del lactosuero para la producción de biocombustibles. Actualmente, los biocombustibles son una fuente potencial de energía renovable con un papel importante como posibles sustitutos de los combustibles fósiles. Por este motivo, la opción de gestionar el lactosuero mediante una valorización energética ha adquirido gran interés durante los últimos años. Entre las alternativas disponibles de aprovechamiento energético, se encuentra la digestión anaerobia, la cual es una de las tecnologías más empleadas para el tratamiento de diverso tipo de residuos. En el caso del lactosuero, se han desarrollado múltiples trabajos en los que se han utilizado diferentes configuraciones y condiciones de operación con el objetivo de mejorar el funcionamiento del proceso. Gracias a estos trabajos se han podido identificar algunos de los factores que limitan su aplicación como son: la tendencia a la acidificación o la limitación de nutrientes. Por este motivo se han promovido otras alternativas como son los procesos de co-digestión con varios materiales o la fermentación oscura. El objetivo de este artículo es la realización de una revisión bibliográfica de los principales trabajos realizados en los que se contemplan los procesos biológicos anteriormente mencionados. Se presentan los resultados más relevantes, así como la influencia de las condiciones de operación y los factores que afectan a la producción de biogás

Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS

The anaerobic digestion process of swine manure was studied when char was used as supplement for improving performance. The use of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was proposed for assessing the organic matter degradation. The assessment on biogas production was carried out using samples of swine manure (SM) supplemented with char in one case and pre-treated by microwave irradiation in the other. This experimental set-up allows for the comparison of the biological degradation observed under these two different configurations and therefore aids in understanding the effect of char particles on the process. Results showed similar performance for both systems, with an average improvement of 39% being obtained in methane production when compared to the single digestion of SM. The analysis of digestate samples by Fourier transform infrared (FTIR) spectroscopy and Py-GC/MS showed improved degradation of proteins, with the Py-GC/MS technique also capable of identifying an increase in microbial-derived material when char was added, therefore highlighting the relevant role of carbon conductive particles on biological systems. Py-GC/MS along with the use of FTIR spectroscopy has proven to be useful tools when evaluating anaerobic digestion

Evaluation of an innovative teaching methodology for engineering involving companies and ICTs in a flipped classroom

This work presents an innovative education experience for engineering students, with the objective of connecting students to labor market, in the context of the regular subject practices, with the analysis of real cases of companies, and using as tools the ICTs and the flipped learning methodology. The assessment of the impact of this innovation education action consisted on the creation of data bases, and the organization of lecturers´ panels, and surveys for students and teachers. The most outstanding drawback raised by teachers was the lack of alignment between the companies’ needs and the curricula of the students. The students appreciated this kind of activity in the subject practices. The students also considered positive the use of ICTs as part of this innovative teaching-learning process, which are familiar technologies for them. According to the teachers, the action contributed to improve autonomous and collaborative teaching in Higher Education

El Problem Based Learning plus, PBL+, a examen, una metodología ecléctica y flexible, para competencias prácticas en ingeniería

[ES] Problem Based Learning Plus (PBL+) es una metodología docente para alcanzar las competencias prácticas en ingeniería, incluyendo a ingenieros químicos, ambientales y agrónomos, y también a biotecnólogos especializados en procesos de producción. PBL+ se basa en la metodología PBL tradicional, pero combina otras metodologías de enseñanza-aprendizaje: la clase invertida, el uso de rúbricas para la evaluación de la actividad, el aprendizaje colaborativo y en algunos casos, el aprendizaje-servicio. Un aspecto relevante es que los estudiantes son libres de elegir el problema sobre el que van a trabajar. Aún más importante es que el problema a resolver debe ser una situación real a la que se enfrenta la empresa. Son los estudiantes los que entran en contacto con una empresa cuyo campo de actividad corresponda a las competencias de la asignatura y seleccionan, junto con un representante de la empresa, el problema a resolver. De este modo, los estudiantes tienen un papel activo en la definición de las prácticas de la asignatura. Esta forma flexible de construir el currículo del estudiante ha demostrado motivarlos, siendo una excelente estrategia para abordar problemas reales de su especialidad. No obstante, no todos los sectores de la ingeniería están dispuestos a compartir sus problemas con los estudiantes. En este sentido, la industria biotecnológica es muy reticente a hacerlo, mientras que el sector agrario es proclive a ello. En este trabajo, se resumen los resultados de la evaluación a la que se ha sometido el PBL+ durante 4 cursos consecutivos, aplicando 9 indicadores que evalúan 7 resultados de aprendizaje. Además, se resume el tipo de problemas sobre los que han trabajado los estudiantes de ingeniería agronómica durante los 4 cursos, que corresponden a los problemas que más preocupan a las empresas del sector: el 60% de los problemas están relacionados con aspectos fitosanitarios, principalmente plagas o enfermedades emergentes. En segundo lugar, el 30% corresponde a alteraciones en el crecimiento de los cultivos por factores abióticos. El 10% restante consiste en adaptar los procesos productivos a los cambios legislativo

Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS

The anaerobic digestion process of swine manure was studied when char was used as supplement for improving performance. The use of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was proposed for assessing the organic matter degradation. The assessment on biogas production was carried out using samples of swine manure (SM) supplemented with char in one case and pre-treated by microwave irradiation in the other. This experimental set-up allows for the comparison of the biological degradation observed under these two different configurations and therefore aids in understanding the effect of char particles on the process. Results showed similar performance for both systems, with an average improvement of 39% being obtained in methane production when compared to the single digestion of SM. The analysis of digestate samples by Fourier transform infrared (FTIR) spectroscopy and Py-GC/MS showed improved degradation of proteins, with the Py-GC/MS technique also capable of identifying an increase in microbial-derived material when char was added, therefore highlighting the relevant role of carbon conductive particles on biological systems. Py-GC/MS along with the use of FTIR spectroscopy has proven to be useful tools when evaluating anaerobic digestion

Is Decentralized Anaerobic Digestion a Solution? Analyzing Biogas Production and Residential Energy Demand

The answer to covering the energy demand of society by increasing the share of renewables must come from the conjunction of several technologies. A preliminary study on the feasibility of anaerobic digestion in residential housing and buildings was carried out, considering a mix of novel and traditional technologies. Different scenarios were evaluated for developed and developing countries, considering small communities and single housing configurations. Anaerobic digestion produces biogas to be used for cooking or heat production, thus aiding in covering the energy demand of residents. There are several aspects still pending a solution regarding medium and small-scale digestion applications under a decentralized waste configuration. The increase in reactor productivity is essential, but social aspects must be considered as well to prevent nuisance caused by offensive odors and legal responsibilities when community digesters create inconvenience to neighbors. Results indicated that using anaerobic digestion to treat residential food and garden waste under a decentralized configuration could scarcely cover 5.8% of the domestic heating demand for highly populated residential urban areas. This value may be increased if assumptions of maximum methane yields are considered, reaching up to 17%. Biological processes may be integrated into a mixed energy production approach, but higher yields are needed to make it realistic. Factors regarding levelized energy production costs are to be carefully considered. Large-scale systems are intrinsically more efficient than small-scale devices, thus making it crucial to establish a critical equilibrium between public acceptance and the scale of technology application