The production of synthetic or substitute natural gas (SNG) from coal is a process of interest in Colombia where the reserves-to-production ratio (R/P) for natural gas is expected to be between 7 and 10 years, while the R/P for coal is forecasted to be around 90 years. In this work, the process to produce SNG by means of coal-entrained flow gasifiers is modeled under thermochemical equilibrium with the Gibbs free energy approach. The model was developed using a complete and comprehensive Aspen Plus model. Two typical technologies used in entrained flow gasifiers such as coal dry and coal slurry are modeled and simulated. Emphasis is put on interactions between the fuel feeding technology and selected energy output parameters of coal-SNG process, that is, energy efficiencies, power, and SNG quality. It was found that coal rank does not significantly affect energy indicators such as cold gas, process, and global efficiencies. However, feeding technology clearly has an effect on the process due to the gasifying agent. Simulations results are compared against available technical data with good accuracy. Thus, the proposed model is considered as a versatile and useful computational tool to study and optimize the coal to SNG process.

The objective of this work was to study the effect of torrefaction temperature on properties of patula pine (Pinus patula) wood that could be of interest for further thermochemical processing. Torrefaction temperature was varied from 200 to 300 °C for 30 minutes using a batch spoon type reactor. Raw and torrefied materials were characterized for proximate and ultimate analyses, thermogravimetry, and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). Results showed that torrefied pine has greater higher heating value and chemical exergy due to the reduction of O/C and H/C ratios. Compared with raw biomass, the material torrefied at 200 and 250 °C did not present significant changes in chemical composition and thermal behavior. Conversely, material torrefied at 300 °C did show important changes in both chemical composition and thermal behavior. Py-GC/MS results suggested that the main constituents of biomass, i.e., hemicellulose, cellulose and lignin, suffer a progressive thermal degradation with increase in torrefaction temperature.

Se presenta una revisión sobre los principales sistemas catalíticos para la síntesis de carveol, carvona, verbenol y verbenona reportados entre 1990 y 2007. Estos compuestos se utilizan en la industria farmacéutica y de alimentos para la producción de fragancias y saborizantes. La creciente demanda de estos productos y la tendencia a nivel mundial de implementar procesos amigables con el ambiente hacen necesario mantener esfuerzos en la búsqueda de sistemas catalíticos de síntesis que resulten económica y técnicamente viables. Se hace énfasis en la oxidación alílica de limoneno y a-pineno. Además, se presentan los avances más recientes de nuestro grupo de investigación en el estudio de reacciones catalíticas basadas en las ftalocianinas.

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