Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measu... more Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.
A pragmatic approach is presented for first screening and design purposes when considering perfor... more A pragmatic approach is presented for first screening and design purposes when considering performing esterifications in a batch process, which combines heterogeneous catalysis and pervaporation for shifting the reaction toward product formation by water removal. A relatively slow esterification between tartaric acid and ethanol was chosen as a model system. Realistic performance of currently commercially available catalysts and ceramic membranes is taken into account by available experimental data. Three different process configurations, which differ in the degree of coupling of reaction and pervaporation, are analyzed. For the esterification reaction system studied, it is shown that a multifunctional membrane reactor is not a viable concept, since its operation does not proximate to the optimal requirements for the two integrated coprocesses. When it comes to configurations where catalytic reaction and separation are performed in separate units, the end design will usually depend on practical issues suc...
A model for the prediction of pressure drop and liquid holdup for trickling flow in packed bed re... more A model for the prediction of pressure drop and liquid holdup for trickling flow in packed bed reactors has been developed, based on the relative permeability concept. The relative permeabilities for gas and liquid as functions of corresponding phase saturations have been studied with 1300 newly measured data pairs of pressure drop and liquid holdup obtained for a wide range
Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measu... more Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.
A pragmatic approach is presented for first screening and design purposes when considering perfor... more A pragmatic approach is presented for first screening and design purposes when considering performing esterifications in a batch process, which combines heterogeneous catalysis and pervaporation for shifting the reaction toward product formation by water removal. A relatively slow esterification between tartaric acid and ethanol was chosen as a model system. Realistic performance of currently commercially available catalysts and ceramic membranes is taken into account by available experimental data. Three different process configurations, which differ in the degree of coupling of reaction and pervaporation, are analyzed. For the esterification reaction system studied, it is shown that a multifunctional membrane reactor is not a viable concept, since its operation does not proximate to the optimal requirements for the two integrated coprocesses. When it comes to configurations where catalytic reaction and separation are performed in separate units, the end design will usually depend on practical issues suc...
A model for the prediction of pressure drop and liquid holdup for trickling flow in packed bed re... more A model for the prediction of pressure drop and liquid holdup for trickling flow in packed bed reactors has been developed, based on the relative permeability concept. The relative permeabilities for gas and liquid as functions of corresponding phase saturations have been studied with 1300 newly measured data pairs of pressure drop and liquid holdup obtained for a wide range
Uploads
Papers by Damjan Nemec