A thermodynamic analysis of hydrogen production from ethanol steam reforming (ESR) is carried out in the present paper. The influence of reactants molar ratio feed into the reforming stage (2.5 < mol Water /mol EtOH < 8), temperature (573 to 1173 K) and pressure (1 < P < 10 atm) over equilibrium compositions is studied. The direct method employed to analyze the system is the minimization of Gibbs free energy (MGFE) in conjunction with Lee-Kesler state equation, using the Kay mixing rules. The temperature and reactants molar ratio showed a positive influence on the hydrogen yield; ethanol conversion is 100% for the whole interval analyzed while the pressure affected greatly the hydrogen production. The carbon deposition exhibits a maximum value at temperatures around 773 K, and three reactions are proposed to describe the solid carbon formation in a wide temperature range based on thermodynamics and experimental predictions. The conditioning stages (mixing, vaporization, and heating) are studied in addition to the reaction to analyze the system quality by means of an exergetic method applying the 2nd law of thermodynamic.
The production process of nitroaromatic hazardous compounds, with the generation of acidic wastewater, represents a significant danger for the health and safety of the workers and the environment. The present study is focused on the development of an efficient installation to treat acidic wastewater resulting from the synthesis process of nitroaromatic compound, considering workers safety and environmental criteria. In this research, a detailed study of the different alternatives that can be used for effective and safe treatment of acidic wastewater was performed. The analysis of several technological schemes for the acidic wastewaters neutralization and the selection of the most feasible alternative from a technical-economic point of view were carried out. The simulation and mathematical modeling developed in this research represent a significant advance in the knowledge of this process for working in a much more secure form. The technological scheme of the process was defined, and the design of the main and auxiliary equipment as well as the piping system was carried out using different computational programs. Finally, this paper proposes a technological design for the treatment of acidic wastewater generated by the production process of nitroaromatic compound, which represents the basic criteria for the further design, construction, and equipment installation of the plant.
The mathematical, multiphysic, multidimensional, and electrochemical modelation of a high temperature solid oxide fuel cell system (planar electrolyte-supported configuration) is discussed in the present paper. The mass transport within the cell is studied using the Stefan-Maxwel model, and the momentum balance is solved by means of Navier-Stokes and Brinkman equations, respectively. On the other hand, the energy balance includes the generation term coupled with the convection and conduction equations. It was demonstrated that the diffusion resistances play an important role in the cell performance, and the oxidant concentration is enough high to work at fuel utilization coefficient of 0.8. The current density suffers a reduction (10 A/m 2 to 1.5 * 10 −3 A/m 2 ) due to the variation of reactants concentration at the cell outlet and the diffusive flux resistances. The developed models can be used to further analyses and to study a solid oxide fuel cell working with other fuels but hydrogen.
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