Quesada-González, Omaida, Cantos-Macias, Manuel A., L-Duharte, Wendy, Pozo-González, Denis M., and Bigñot-Favier, Liudis C.
Revista Cubana de Química. sep-dic2019, Vol. 31 Issue 3, p159-176. 18p. 2 Diagrams, 7 Charts, 1 Graph.
BIOMASS, PYROLYSIS, COAL, BIOCHAR, HEATING, THERMAL analysis, and RENEWABLE energy sources
The objective of this work is to determine the influence of the type of biomass and the heating rate (β) on the pyrolytic decomposition kinetics of Teca and Guachapelí. Experimentally, chemical and energetic biomass were characterized using elemental and immediate analysis and the sample was pyrolyzed using two thermal analysis equipment, one conventional (ATG) and one of simultaneous analysis (ATG, TGD, CDB). The chemical characterization demonstrated the potentialities of biomass as energy sources. The kinetic study carried out identified kinetic models and activation energy values for the devolatilization of hemicellulose, cellulose and lignin for both woods, demonstrating that the F1 model should not be chosen a priori, as the determinant. The influence of the heating rate and the type of biomass on the obtained kinetic results is demonstrated, therefore, results of low to high heating rates should not be extrapolated. [ABSTRACT FROM AUTHOR]
Angel Cantos-Macías, C. Manuel, Omaida Quesada-González, C., Ross-Mesa, Alejandro, Luis Brito-Soubanell, C. Angel, and Casanova-Gómez, Abdel
Revista Cubana de Química. sep-dic2018, Vol. 30 Issue 3, p400-422. 23p. 13 Charts, 5 Graphs.
PYROLYSIS, WOOD waste, PYROLYSIS kinetics, AGROFORESTRY, TEAK, and WOOD chemistry
The use of food as a source of energy has been questioned and agroforestry waste shows potential for these purposes. The objective of the work is to realize the chemical and energetic characterization of waste from Ecuador and study the kinetics of its pyrolysis, as an alternative for its use. Elemental, immediate analysis was carried out and thermal analysis techniques were applied. The higher carbon content and lower humidity and ash of Teak, favor its energétic use, with respect to Fernán Sánchez. In addition, its nitrogen and sulfur contents below 1 %, guarantee low NOx and SO2 emissions, reducing its environmental impact. The combined use of TGA, DTG and DSC allows to identify the three stages of pyrolytic cracking, the decomposition of hemicellulose, cellulose and lignin. His kinetic study showed that the first and third stages are determined by diffusive processes fundamentally and in the second, different kinetic models prevail. [ABSTRACT FROM AUTHOR]
Omaida Quesada-González, C., Enrique Alfonso-Martínez, Félix, Enelio Torres-García, C., Ángel Cantos-Macías, Manuel, and Antonio-Revilla, Juan
Revista Cubana de Química. ene-abr2018, Vol. 30 Issue 1, p27-44. 19p. 4 Charts, 7 Graphs.
ORANGE peel, COMBUSTION, DYNAMICS, ANALYTICAL mechanics, THERMOGRAVIMETRY, HEMICELLULOSE, and ACTIVATION energy
The kinetic study of orange peel combustion has been conducted using experimental results of the termogravimetric analysis. This study made use of several equations: Coats (integral), Sharp y Achar (differentials) and Isoconversion (free kinetic). By means of the combination of these equations, the kinetic results for natural materials are more reliable. The final kinetic models are D4-D2 for dehydration, decompositions of hemicellulose and cellulose by D4, and F1 for lignin. The rank of energy activation ranges 80-90 kJ/mol (kinetic free) and 48-162 kJ/mol (model fitting method) because simultaneous reactions occur. [ABSTRACT FROM AUTHOR]
Cantos Macías, Manuel Ángel, Quesada González, C. Omaida, Mcfarlanes, Rafael Rodríguez, Brito Soubanell, C. Angel Luis, and Gómez, Abdel Casanova
Revista Cubana de Química. set-dic2017, Vol. 29 Issue 3, p362-378. 17p. 9 Charts, 2 Graphs.
WOOD waste, PYROLYSIS kinetics, PYROLYSIS, and RENEWABLE energy sources
The uses of forest residues or bushes, such as the Marabou, as a renewable resource of energy take economic and environmental importance. This work aims to characterize the Guachapelí (Ecuadorian) and Marabou (Cuban) woods chemically and energetically and study their kinetics of pyrolytic devolatilization. For this purpose, elemental, immediate analysis, and thermal analysis techniques such as Thermogravimetric Analysis, Differential Thermogravimetric and Differential Scanning Calorimetry were performed. The study showed that the chemical characteristics of the biomasses examined explain the high values of determined higher caloric power, and justify their sustainable thermal energy utilization. The kinetic analysis of the pyrolytic decomposition of these biomasses determined the kinetic models and activation energy for each step. Besides, the combination of the Coats (Integral) and Achar (Differential) equations contributes to counteract the limitations of the model-fitting Method with respect to the kinetic model. [ABSTRACT FROM AUTHOR]
Quesada-GonzáLez, Omaida, Llópiz-Yurell, Julio Cesar, and Torres-Torres, Enelio
Revista Cubana de Química. ene-abr2016, Vol. 28 Issue 1, p350-363. 14p. 3 Charts, 4 Graphs.
THERMOGRAVIMETRY, THERMAL analysis, ANALYTICAL mechanics, DEHYDRATION reactions, and ACTIVATION energy
Sample Controlled Thermal Analysis and High-resolution Thermogravimetry are used for to study the dehydration of BaCl2·2H2O. Model controlled by 2-dimensional interfacial advancement (R2) and activation energy of 26 kJ/mol were calculated when the technique SCTA was applied and a 3-dimensional diffusive kinetic model (D3) and activation energy of 40 kJ/mol were determined when Hi- Res ATG was applied. The influence of atmosphere and particularly of the residual pressure in environment of the samples on the calculated kinetic parameters was demonstrated. [ABSTRACT FROM AUTHOR]
CHEMICAL kinetics, SULFUR dioxide, ACETYLENE, COMBUSTION gases, and GRAVIMETRIC analysis
The present work is developed to obtain the kinetic curves of the reaction between SO2 and the wastes of acetylene production. For this purpose, it is designed and built an experimental installation, ant it is studied the reaction kinetics between 200-400 °C of temperature and the SO2 concentration levels between 2-6 %. The results show the possibility of using these wastes in the sulfur dioxide reduction in the combustion gases. [ABSTRACT FROM AUTHOR]
DYNAMICS, SOLAR dryers, SEEDS, CORN, SOYBEAN, and GOURDS
In the present work are shown results of kinetical tests of a low cost solar dryer for seeds. Tests were made using corn, soja, and gourd seeds, and results are according to this simple and useful technology based in polietilenum covers. From these tests is clear that drying of seeds from 1 to 3 kg/m² day in those dryers is a potential alternative solution for seed drying in our country. [ABSTRACT FROM AUTHOR]
Salas V., M. E., Rabilero B., A. C., and Córdova R., V.
Revista Cubana de Química. 2001, Vol. 13 Issue 3, p49-55. 7p.
CEMENT, CEMENT industries, CEMENT plants, FACTORIES, and POZZUOLANAS
Is present results obteined in kinetics study made to the moliend sistems in the cement factory "Palamarito de Cauto", Santiago de Cuba, by the puzolanic cement production PZ-250 with adition of pozzolanas until 40%. The present work endorse the carried out predictions satisfactorily and they allow to recommend their utilization like a reliable medium the efficiency economic. [ABSTRACT FROM AUTHOR]
COFFEE, SOLAR dryers, DRYING apparatus, DYNAMICS, and CHEMICAL reactions
It is accomplished a kinetic analysis of the coffee dry in different solar dry equipment. The method used for the study combines the graphic treatment of the problem with the analytical one. The graphical description of the process is achieved through the curves of dry (moisture vs. time) and dry speed of the product (dry speed vs. time and moisture of the product) widely described in the literature. For the analytical study it is applied a formal kinetic method previously developed by the authors on the bases of the formal kinetics of the chemical reaction. They were considered different technological options of solar dry developed in the Research Center of Solar Energy (Santiago of Cuba). The obtained results demonstrate that in spite of the differences observed among the evaluated solar technologies, the process of coffee dry is carried out substantially by the same kinetic mechanism, similar kinetic behaviors were registered in all the studied cases. [ABSTRACT FROM AUTHOR]
Jáuregui-Haza, Ulises J., Díaz-Abín, Osmell, Wilhelm, Anne M., and Delmas, Henri
Revista Cubana de Química. 2006, Vol. 18 Issue 1, p296-297. 2p.
HYDROFORMYLATION, CHEMICAL kinetics, ETHYLENE compounds, CATALYSIS, and ORGANOMETALLIC chemistry
Se describe un estudio cinético comparativo de la hidroformilación del octeno (por catálisis en fase acuosa soportada) en el interior y exterior de los poros de un soporte (sílice). Se representaron los parámetros del proceso y la velocidad de reacción mediante los modelos semiempíricos de Deshpande y de Jáuregui-Haza. Se observa una mayor velocidad de reacción cuando ésta ocurre dentro de los poros y se afirma la superioridad del modelo de Jáuregui-Haza.
Cortés, Isnel Benítez, Ramos Sánchez, Luis Beltrán, and Rodríguez, Agustín García
Revista Cubana de Química. 2006, Vol. 18 Issue 1, p108-108. 1p.
DESULFURIZATION, CHEMICAL reactions, SULFUR dioxide, LIME (Minerals), TECHNICAL chemistry, and SULFUR dioxide mitigation
Se estudia el proceso de desulfuración de gases con dióxido de azufre mediante partículas con alto contenido de CaO. Los resultados indican una baja conversión de dióxido de azufre debido al taponamiento de los poros de las partículas. El estudio ofrece un modelo cinético para ser utilizado en el futuro diseño de reactores químicos.