no. 12 (septiembre 2015)

Permanent URI for this collectionhttps://dspace-test.ucuenca.edu.ec/handle/123456789/23903

Browse

Now showing 1 - 8 of 8

Diseño del proceso de una torre de vacío. Ventajas de la simulación
(Universidad de Cuenca, 2015-09) Vega, Macarena; Ale Ruiz, Liliana; Martínez, Julieta; Erdmann, Eleonora
Heavy hydrocarbons are the greatest oil resource in the world, however in the past had been put aside as an energy resource due to the difficulties and costs associated with production, [1]. Nowdays, the industry is financing this research because of the importance of production and the characterization. To analyse the vacuum tower, we need ASTMD1160 temperature at 10 mmHg and oil density, thereafter it can be obtained the curve of TBP760 (True Boiling Point). To correlate different boiling points with vaporized percentages for each change of pressure on the products, is necesary to build up a phase diagram with the EFV760 (Equilibrium Flash Vaporization) and EFV10 temperature. The simulator through internal calculations resolves the phase diagram, compared with the difficulty posed by manual calculations. In this paper a vacuum tower simulator is developed by Aspen HYSYS V8.3, and using the heavy oil as input data. The major advantage of the theoretical designed simulation process is the time resolution
Análisis de las simulaciones del proceso de deshidratación del gas natural con Aspen Hysys y Aspen Plus
(Universidad de Cuenca, 2015-09) Benitez, Leonel Alberto; Gutiérrez, Juan Pablo; Ale Ruiz, Liliana; Erdmann, Eleonora; Tarifa, Enrique
Natural gas has taken an important strategic role in world energy supply as a result of the growing global energy demand. Water is probably the most undesirable component found in raw natural gas because its presence can produce hydrate formation, and it can also lead to corrosion or erosion problems. Due to these often expensive consequences natural gas should be subjected to conditioning processes in order to achieve strict specifications for sales, transportation and final uses. In recent years, process simulation is playing an important role in the oil and gas industry as an appropriate and powerful tool for the design, characterization, optimization, and monitoring of industrial processes performance. In this paper the development of two steady state simulations of natural gas dehydration by absorption with triethylene glycol (TEG) is described, using commercial process simulators such as Aspen HYSYS V8.3 and Aspen PLUS V8.2. Natural gas composition, plant configuration and operating conditions adopted for designs and simulation are those generally used in the area in conditioning plants of natural gas in the province of Salta (Argentina).
Exposición a monóxido de carbono en trabajadores de control vehicular-Cuenca: estudio exploratorio
(Universidad de Cuenca, 2015-09) Rosas, Ruth; Ochoa, Angélica; Morillo, Diana; García, Nancy; Andrade, Susana
This exploratory study aims to evaluate the carbon monoxide exposure expressed as percentage of carboxyhemoglobin (%COHb) among the vehicle-examiners of the vehicle control centers (VCC) “DANTON”-Cuenca. All the employees (N=55) in both VCCs in Cuenca (Capulispamba and Mayancela) were included. Blood samples taken at the beginning and at the end of the journey of one day at early February, April and July 2013 were used to estimate %COHb. The results show that the %COHb increased from the beginning to the end of the journey among employees in both VCCs and among smokers and nonsmokers (P<0.001). Among non-smokers (N=42), the %COHb at the end of the journey was higher than the biological limit value (BLV) of 3.5% only for Mayancela employees (4.12%, P<0.05). Among smokers, the mean %COHb at the end of the journey was higher than the BLV in both VCCs. In general, Mayancela employees and those who smoke showed higher exposition to CO measured as a %COHb.
Análisis de ciclos fusión-solidificación de ceras de parafina
(Universidad de Cuenca, 2015-09) Reyes, Alejandro; Vásquez, José; Sepúlveda, Francisco
The global energy shortage has prompted for research of accumulate renewable energy alternatives, i.e., solar energy. Paraffin wax has a Phase Change Material (PCM) which allows to accumulate energy. Depending on their physical composition the melting temperature could be between 40° and 65° C, respectively. However, there is lack of information regarding the wax´s material chractersitcis after high number of cycles. Therefore, in the present work, a paraffin wax fusion/solidification system was designed and it further implemented. It was also used a data recording system to analyze melting, solidification cycles, and temperature profiles in the time domain. . The wax was heated and cooled in a Peltier cell. Two types of wax were analyzed for about 1000 cycles. It was analyzed periods and amplitudes of each cycle. The time cycle for PT 58 and PT Ch wax were 340 and 160 seconds, respectively. Finally, the results showed that the temperature profiles have no significant differentes, this means that the waxes do not undergo chemical or structural changes.
Validación de la simulación numérica del flujo bifásico hidrodinámico en sistemas de lecho fluido
(Universidad de Cuenca, 2015-09) Mantilla N., Irla; Gonzáles Ch., Salome
This rresearch work aims to improve the validation process of two-phase flow numerical simulations, of the fluid bed characteristic transport, through the formulation and development of a combined numerical model Finite Volumes and Finite Element methods. The simulation process, inicially, was performed by COMSOL software and the obtained results showed higher accuracy compare with Discrete Element Method implemented by MFIX. The fundamental problem of bed fluid mathematical modeling phenomenon is the domain irregularity, the coupling variables in space and nonlinearity. In this research conservative equations are formulated, such as, to produce a variational equivalent and numerically solvable problem. A state equation based on the hydrodynamic pressure and the volume fraction of solids is defined. The system was decoupled into three sub-problems, ensuring the solution existence of general problem. A comparison of obtained results showed that the model developed in this article, check more effectively optimal mixing conditions, based on the quality of bubbling and mixing speed.
Relación entre el uso efectivo de las TIC y las decisiones gerenciales en PYMES
(Universidad de Cuenca, 2015-09) Mosquera Laverde, William Eduardo; Rojas Melo, Luisa Alejandra; Grillo Torres, Camilo Mauricio
The article is based on the results of an exploratory study on Information Technologies Communication (ICT) and managerial decisions in small and medium enterprises (SMEs). The idea is to find out the reason to the company’s low permanence factors in the market. They have: inefficient models application of internal and external communication, reduced use of ICT implemented inside the company, inappropriate use of computer packages and underutilization of additional services provided by Internet operators. It was found also out the administrative organization have small organizational behavior management which is inoperative. All the above factors affects management decisions. Therefore, an analysis of weak managerial aspects, especially the information flow of the use of ICT through an exploratory qualitative research presented as a series of possible correct steps and strategies to implement design was developed to face the Free Trade Agreement (FTA) in Colombia. Finally, the advantages of efficient communication presented through operational and IT measures, showing some management tools to be taken to improve productivity.
Remoción de iones cromo y cobre desde soluciones acuosas con cenizas volantes de carbón mineral
(Universidad de Cuenca, 2015-09) Saavedra Q., María Luisa; Cuevas A., Daniela; Saldivia M., Marcela; Santoro G., Rosa
This study analyzes the use of fly ash, from an electrical power plant, to be used as adsorbent material in an aqueous solutions o chromium and copper ions, to use in treatment of waste water from mining operations. The fly ash analyses of FRX and DRX, mainly showed Si, Al, Fe and O. The above components are primarily responsible for the surface patterns, with a pH of 10.66 for the full sample and 3.7 point of zero charge. Therefore, adsorption of Cr (VI) as HCrO4-(anionic) is favored at pH2 with a removal of 67.98%. This removal increases as the concentration of the metal is reduced, reaching a 79.30% at 10 [mg /L] chromium. In the case of copper (cationic character), an adsorption of 100% is obtained at pH 4, independent of the contact time, 1 hour of exposure peaks removal. It is concluded that the fly ash of coal, currently, considered a waste material. It can be used as unconventional adsorbent material of metal ions under acid pH 4, attributed mainly to the presence of SiO2, Al2O3 and Fe2O3.
Modelo teórico para cuantificar la eficiencia térmica del calentador eléctrico en una secadora doméstica de ropa
(Universidad de Cuenca, 2015-09) Ruiz, Luis Alberto; Sánchez, Alvaro; Caudillo, Martín; Miranda, Víctor; Ballesteros, Luis
In this research paper, enhancement of generation and transfer heat on a tumbler dryer electric heater is achieved by a developed theoretical model, through the thermal efficiency estimation on the electric heater. Air mass flow and electric power interaction in the heater were used as inputs, and thermal efficiency was defined as the output of the model. It was considered the electric heater as an isolated component. Heater efficiency tests were performed in order to obtain the theoretical-physical correlation. From the obtained results, a typical over-damped system behavior was identified and a mathematical model that follow this trend was proposed. The R square prediction coefficient wass 0.96. Finally, the model was evaluated with high air mass flow getting a maximum relative error about 0.66 %, and provides enough information to rise heater thermal efficiency up to 7.7%. The power range for the model to predict efficiency is from 1 KW to 5 KW, the same as the recommended power range for use.

Browse

Browsing no. 12 (septiembre 2015) by Issue Date