Monitoring and controlling stability in anaerobic digestion (AD) systems are essential, since it allows to obtain information that helps to take corrective actions in case of deviations in the system and to guarantee a stable performance in the biogas production. In this work, a pilot-scale CSRT reactor (1 m³) was monitored during the anaerobic digestion of pig manure with thermal pretreatment (80 °C) operated at thermophilic temperature (45 °C). The ratio of the volatile organic acids (FOS) to the total inorganic carbonate (TAC) and the pH were the indicators used during the monitoring process to identify deviations in the AD system. Additionally, alkaline solution NaOH (98%) was applied to counteract pH deviations and maintain stability. Chemical oxygen demand (COD) and biogas composition were measured during the AD process. It was found that during the AD process, the FOS/TAC was between the range of 0.5 and 1. The results revealed that, in the anaerobic digestion of pig manure with thermal pretreatment, the pH was kept stable in the range of 6.7–7.4 since no medium acidification occurred. Additionally, the tendency of the chemical oxygen demand decreased from the 10th day of operation, product of the favorable enzymatic activity of the microorganisms, reflected in the stable production of biogas (69% ${\mathrm{CH}}_4$). Finally, it is concluded that thermophilic AD of pig manure with thermal pretreatment is a good option when it is carried out efficiently by employing an adequate energetic integration.

Waste management technologies have become a way to generate value-added products. Anaerobic digestion (AD) allows biogas generation by treating organic wastes. In this work, the methanogenic potentials of anaerobic digestion of rumen and chicken manure, two typical agro-industrial wastes from the Colombian Caribbean region, were evaluated. On a first stage, the effect of temperature on anaerobic digestion of manure inoculated with liquid rumen was measured. Results revealed that the thermophilic digestion produces more biogas (up to 47% higher than the mesophilic digestion), but the mesophilic digestion has better biogas quality (up to 20% more methane than the thermophilic digestion). On the second experimental stage, it was assessed the effect of temperature regimen and the addition of fat-oil-grease (FOG) on cumulative biogas production, methane percentage, and physicochemical parameters. It was found that the anaerobic digestion of the rumen with FOG in mesophilic conditions had the best performance in terms of quantity and quality of biogas (2520 NL CH₄/kg VS, CH₄ 93%, H₂S 1 mg/L, H₂O 16 mg/L). Finally, rumen and manure had methane concentrations above 40% in all cases studied, after 60 days of anaerobic digestion. It was concluded that rumen and manure are good candidates for biogas generation.

Actualmente en Colombia el porcentaje de generación de electricidad a partir de fuentes renovables es muy baja, siendo la eólica la de mayor participación con 0,1% de la demanda eléctrica. Para lograr una seguridad energética más robusta en el mediano y largo plazo, en Colombia debe existir una política energética que tenga en cuenta las complementariedades e implementación de tecnologías y fuentes de energía con una importante disponibilidad a lo largo del territorio nacional. En la zona norte colombiana, específicamente en la región Caribe, los recursos renovables son amplios y variados, lo que favorece la transición a este nuevo modelo de generación energética. En este artículo se realiza un estudio estadístico basado en el análisis de variables eólicas como la velocidad y, dirección del viento y, a partir de los resultados, los que evidencian un gran potencial, se puede inferir que podría abastecerse la demanda energética de la región a partir de parques eólicos, por lo que se tendría un uso eficiente del recurso energético disponible en la región, específicamente en el departamento del Atlántico, donde se encontraron valores apreciables de este recurso.

Using simultaneous thermogravimetrical analysis coupled with mass spectroscopy, the pyrolysis of African palm husk, using several heat rates and programs was performed. Seven relations of mass/charge were followed of the evolved gas of the pyrolysis process, fitting the kinetics and the mass spectroscopy signals to the distributed activation energy model (DAEM) with different numbers of pseudo-components. Fitting with four pseudo-components proved to be the best for modeling the thermal degradation process. Kinetic parameters were not affected by the heating rate or program employed, which agrees with other reports for similar biomass. Methane, methanol formaldehyde, furfural were successfully fitted to the DAEM model, nevertheless CO2 and NO2 were not able to be represented by this model due to its production in secondary reactions in gaseous phase.

Este trabajo describe la contribución de los investigadores de todo el mundo en el campo de la grafitización de antracitas en el período comprendido entre 1960 – 2018. Se desarrolló un análisis bibliométrico para examinar las publicaciones científicas en este campo utilizando las bases de datos Scopus Elsevier, Journal Citation Reports, Scimago Journal & Country Rank y herramientas informáticas. Se analizaron diferentes aspectos de las publicaciones tales como tipo de publicación, principales áreas de investigación, principales revistas, citaciones,etc. Los artículos publicados provienen principalmente de China, Estados Unidos, Francia, España, Japón y Canadá con un número de publicaciones de 75, 37, 32, 27, 18 y 16 respectivamente. Los resultados ayudarán a los investigadores a comprender la situación actual de la investigación en el campo de la grafitización de antracitas.