The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
Henri Delmas - One of the best experts on this subject based on the ideXlab platform.
-
partial hydrogenation in an upflow fixed bed reactor a Multistage Operation for experimental optimization of selectivity
Industrial & Engineering Chemistry Research, 2003Co-Authors: Frank Stuber, Henri DelmasAbstract:The selectivity performance of an upflow fixed-bed reactor was optimized for the exothermic consecutive hydrogenation of 1,5,9-cyclododecatriene (CDT) to cyclododecene (CDE) over 0.5% Pd/alumina. The influence of the main operating variables (temperature, hydrogen pressure, and liquid and hydrogen flow rates) on global hydrogen conversion and CDE selectivity was studied and analyzed. The reactor performance obtained for a pellet catalyst was shown to be sensitive to external mass transfer of the gaseous reactant and backmixing in the liquid phase. The surface concentration of hydrogen was found to be the key parameter because of its opposite effect on the rate of hydrogenation and selectivity. Increasing the gas velocity provided a higher hydrogen concentration at the catalyst surface, enhancing the global rate of hydrogenation, although an increase in the global hydrogen conversion was always related to a reduction of CDE selectivity. When the liquid velocity was decreased, backmixing became important in the liquid phase, also resulting in a loss of selectivity. To improve the reactor performance in terms of selectivity, process staging and hydrogen dilution by an inert gas were tested. Both, but in particular the split-up of the process into several stages, proved to be successful in obtaining high yields of CDE up to 90%, required for industrial application.
Sayanasri Varala - One of the best experts on this subject based on the ideXlab platform.
-
desorption studies for the recovery of radionuclides th and zr and optimization using taguchi mixed design l18 2132 a regeneration step for loaded biosorbent general mathematical model for Multistage Operation
Journal of environmental chemical engineering, 2017Co-Authors: Sayanasri Varala, Rajarathinam Parthasarathy, Suresh K Bhargava, Satyavathi BankupalliAbstract:Abstract Thorium and zirconium are the most stable radionuclides used in various nuclear Operations and the removal of them from aqueous industrial streams is essential. Biosorption is one of the most effective removal processes and it will be more attractive if loaded biomass can be regenerated for reuse. Reported studies on the desorption of metal ions from loaded biomass is limited in the literature. The present study aims to investigate the desorption of Th and Zr from loaded deoiled Karanja seed cake (DKSC) and study the efficiency of desorption process. All desorption experiments were carried out under batch mode using different eluents by varying liquid to solid (L/S) ratio, eluent type and concentration. Taguchi mixed level design L18(2132) was used to optimize the process and achieve the maximum desorption efficiency (D%). The eluent concentration was found to be the major factor that affects desorption. The optimum conditions for maximum D% inlcude 1 M HCl at L/S ratio of 7 with a recovery of 96% and 0.1 M NaHCO3 at L/S ratio of 3 with a recovery of 69% for thorium and zirconium, respectively. It was also shown that desorption kinetics follows pseudo-second order for both thorium and zirconium at optimal conditions. The regenerated DKSC was found to possess properties similar to those of native DKSC. A simple mathematical model was developed for computing the concentration of metal ions in the eluent in a counter-current multi-stage desorption system and validated using thorium desorption kinetic data.
A. Fecske - One of the best experts on this subject based on the ideXlab platform.
-
Small Diameter Multiple Hydrocyclone for Starch Processing
Starch-starke, 2006Co-Authors: A. FecskeAbstract:The traditional application of small diameter multiple hydrocyclone batteries in the starch industry is the refining of maize, wheat, potato, and manioc starch by countercurrent washing in Multistage Operation. A new type of multiple hydrocyclone battery for these purposes is discussed. Construction details, internal flow passage, selection of construction material, and some Operational characteristics of the battery are taken into consideration as well as its easy, handling. As an example of application of a small diameter hydrocyclone system, a new process alternative for manufacturing of potato starch is presented. The process has a fresh water consumption for starch extraction and refining of 300–350 l/t potatoes or ∼ 1.9 – 2.2 t of water per ton of refined DS starch, due to the unique combination of process stages by adapting a hydrocyclone system, screens, and centrifugal separators.
Satyavathi Bankupalli - One of the best experts on this subject based on the ideXlab platform.
-
desorption studies for the recovery of radionuclides th and zr and optimization using taguchi mixed design l18 2132 a regeneration step for loaded biosorbent general mathematical model for Multistage Operation
Journal of environmental chemical engineering, 2017Co-Authors: Sayanasri Varala, Rajarathinam Parthasarathy, Suresh K Bhargava, Satyavathi BankupalliAbstract:Abstract Thorium and zirconium are the most stable radionuclides used in various nuclear Operations and the removal of them from aqueous industrial streams is essential. Biosorption is one of the most effective removal processes and it will be more attractive if loaded biomass can be regenerated for reuse. Reported studies on the desorption of metal ions from loaded biomass is limited in the literature. The present study aims to investigate the desorption of Th and Zr from loaded deoiled Karanja seed cake (DKSC) and study the efficiency of desorption process. All desorption experiments were carried out under batch mode using different eluents by varying liquid to solid (L/S) ratio, eluent type and concentration. Taguchi mixed level design L18(2132) was used to optimize the process and achieve the maximum desorption efficiency (D%). The eluent concentration was found to be the major factor that affects desorption. The optimum conditions for maximum D% inlcude 1 M HCl at L/S ratio of 7 with a recovery of 96% and 0.1 M NaHCO3 at L/S ratio of 3 with a recovery of 69% for thorium and zirconium, respectively. It was also shown that desorption kinetics follows pseudo-second order for both thorium and zirconium at optimal conditions. The regenerated DKSC was found to possess properties similar to those of native DKSC. A simple mathematical model was developed for computing the concentration of metal ions in the eluent in a counter-current multi-stage desorption system and validated using thorium desorption kinetic data.
Frank Stuber - One of the best experts on this subject based on the ideXlab platform.
-
partial hydrogenation in an upflow fixed bed reactor a Multistage Operation for experimental optimization of selectivity
Industrial & Engineering Chemistry Research, 2003Co-Authors: Frank Stuber, Henri DelmasAbstract:The selectivity performance of an upflow fixed-bed reactor was optimized for the exothermic consecutive hydrogenation of 1,5,9-cyclododecatriene (CDT) to cyclododecene (CDE) over 0.5% Pd/alumina. The influence of the main operating variables (temperature, hydrogen pressure, and liquid and hydrogen flow rates) on global hydrogen conversion and CDE selectivity was studied and analyzed. The reactor performance obtained for a pellet catalyst was shown to be sensitive to external mass transfer of the gaseous reactant and backmixing in the liquid phase. The surface concentration of hydrogen was found to be the key parameter because of its opposite effect on the rate of hydrogenation and selectivity. Increasing the gas velocity provided a higher hydrogen concentration at the catalyst surface, enhancing the global rate of hydrogenation, although an increase in the global hydrogen conversion was always related to a reduction of CDE selectivity. When the liquid velocity was decreased, backmixing became important in the liquid phase, also resulting in a loss of selectivity. To improve the reactor performance in terms of selectivity, process staging and hydrogen dilution by an inert gas were tested. Both, but in particular the split-up of the process into several stages, proved to be successful in obtaining high yields of CDE up to 90%, required for industrial application.
