A numerical model has been established and solved to describe the dehydration reaction from alcohol to ethylene. The influences of the gas velocity and the temperature of the feeding gas to the process of the reaction were discussed. The results showed that, the influence of the radial diffusion on the reaction characteristics could be ignored while the influence of radial heat conduction to the temperature distribution was significant. The temperature distribution decreased alone the axial direction at first and then increased, that is a lowest point of the temperature could be found. When the velocity of the gas slowed down or the temperature of the feeding gas increased, the conversion of the reactant and the selectivity of the target product could be improved, the distance of the lowest temperature point to the entrance got closer and the outlet temperature became higher.
Taken the pore structure effects into account, a mathematical model to describe the interaction of mass transfers, the chemical reaction and the pore structure in the gas sensitive porous medium is presented and solved. The properties of the mass transfers and the reaction characteristics of the gas-sensitive porous system are analyzed. The effects of pore size distribution and porosity on the concentration field of detected gas and the effective utilization degree of the porous matrix are provided. The results indicate that the Thiele number, which can reflect the relative magnitude of chemical reaction rate and gas diffusion velocity in nature, is the main basis for judging the effects of various parameters. It usefully reproduces the observed effects of pore structure and reaction temperature on diffusion and chemical reaction response, showing that the gas sensitivity and the effective utilization coefficient of the gas sensitive porous medium can be controlled by adjusting key parameters.
According to the assumption of local thermal non-equilibrium and the heat transfer controlled regime, a mathematical model describing the coupling between the heat and mass transfer processes in a porous packed bed with endothermic chemical reactions was established and solved by the alternate dimension implicit method. The calculated results showed that, the profiles of the temperature distributions of the two phases and the solid conversion ratio all decay near the radial boundary wall corresponding to the momentum boundary layer. However, the concentration of the product gas increases near the wall owing to the slower speed layer. The temperatures difference between the gas flow and solid pellets can not be ignored during the study of ore decomposition in the porous packed bed. The reaction features of the packed bed with endothermic reactions under different conditions can be analyzed by the established model.
Photoelectrocatalytic oxidation of methyl orange on TiO2 films were investigated in KNO3 solution. In the potential range up to 1.2 V, electro-degradation rates were fairly low that was less than 1%. Degradation rates on the two films were larger at higher potentials. The film prepared without PEG showed better activities than the film prepared with PEG during the whole range of potential. Methyl orange degradation rate increased with increasing KNO3 concentration from 0 to 0.010 mol/l. After 120 min of irradiation, methyl orange degradation rate on the film with PEG was 89.5%, while degradation rate on the film without PEG was 92.0% after the same period.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.