Matthaus Babler - Academia.edu (original) (raw)
Papers by Matthaus Babler
Chemical Engineering Science
A hollow core shell model for describing chemisorption of H2S from raw syngas in a packed bed rea... more A hollow core shell model for describing chemisorption of H2S from raw syngas in a packed bed reactor of ZnO
Particle laden flows with reactive particles are common in industrial applications. Chemical reac... more Particle laden flows with reactive particles are common in industrial applications. Chemical reactions inside the particle or deposition at the surface can generate additional flow phenomena that affect the heat, mass and momentum transfer between the particle and bulk flow. This work aims at investigating the effect of Stefan flow on the drag coefficient of a spherical particle immersed in a uniform flow. Fully resolved 3D simulations were carried out for particle Reynolds numbers based on the free stream velocity ranging from 0.5 to 3. Simulations are carried out in foam-extend CFD software, using the Immersed Boundary(IB) method for treating fluid-solid interactions. The simulations were validated against data for particles without reactive flow, and against the analytical solution for Stefan flow around a particle in a quiescent fluid. We found that in the considered range of Reynolds number the drag coefficient decreases linearly with in increase in Stefan flow velocity.
The hydrodynamic breakup of small inertial aggregates in homogenous and isotropic turbulence is s... more The hydrodynamic breakup of small inertial aggregates in homogenous and isotropic turbulence is studied through numerical simulations. Small inertial aggregates are subject to shear stress caused b ...
Industrial & Engineering Chemistry Research, 2021
In this study, NH 3 adsorption isotherms for a commercial vanadium-based SCR catalyst coated on a... more In this study, NH 3 adsorption isotherms for a commercial vanadium-based SCR catalyst coated on a monolith substrate were obtained using a gas flow reactor over a wide range of parameters which have not been performed before in a single study. The isotherms were obtained under different conditions, where adsorption temperature, NH 3 concentration, water concentration, washcoat loading, and catalyst oxidation state were varied. For this purpose, a systematic data processing method was developed, which characterizes the dispersion and delay effects in the experimental setup using a residence time distribution model, and artifacts such as NH 3 adsorbed in the experimental setup and uncertainties in the washcoat loading were removed. As a result, data from different catalyst samples were integrated, and adsorption isotherms with low data spread and well-defined regions were obtained. This allows the identification of the complex nature of the catalyst and dynamics, where multiple types of adsorption sites are present. For instance, the oxidized catalyst has 50% higher NH 3 storage capacity compared to the reduced state of the sample. Moreover, water reduces the NH 3 storage capacity at high concentrations (5.0%), whereas at low concentration (0.5%), water increases the NH 3 adsorption capacity for an oxidized catalyst. The proposed data processing method can be extended for the analysis of further phenomena in catalysts studied using gas flow reactors, complementing current methods and providing information for models with extended validity and lower parameter correlations.
Energy Procedia, 2017
District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.
Energy Procedia, 2017
This work reports the results of the life cycle assessment (LCA) of two carbonation processes aim... more This work reports the results of the life cycle assessment (LCA) of two carbonation processes aimed at permanent CO 2 storage, employing Basic Oxygen Furnace (BOF) slag from steel manufacturing as alkalinity source. Specifically, the performance of the slurry phase and wet carbonation routes were compared assuming to store the CO 2 emitted from a 10 MW conventional natural gas power plant. The LCA was based on the material and energy requirements for each of the involved process steps, i.e. pretreatment and transport of raw materials, CO 2 compression, carbonation, post treatments and management of the obtained products. The slurry and wet route resulted in a net avoided greenhouse warming potential (GWP) of 473 and 384 kg CO 2 /MWh el , respectively. Nevertheless, both routes affected the other environmental impact categories. In general, the wet route had approximately two times higher impact than the slurry route, due in particular to the higher material and energy requirements. An exception was the abiotic resource depletion which resulted higher for the slurry route due to greater water requirement with respect to the wet route. The contributions to all mid-point impact categories were mainly due to energy requirements. A sensitivity analysis showed that the environmental impacts are affected by the energy mix and by the transport distance of slags and carbonation products.
British Journal of Applied Science & Technology, 2015
Lake Katwe is the largest of the eight saline crater lakes in the pleistocene Katwe-Kikorongo vol... more Lake Katwe is the largest of the eight saline crater lakes in the pleistocene Katwe-Kikorongo volcanic field situated in the western arm of the great East African Rift system in southwestern Uganda. The salt lake is hydro-chemically of a carbonate type with its brines representing an important source of mineral salts of high economic value. In the present work, the geochemical simulation of the crystallization route of the natural evaporation of the lake brine in ls was done. The precipitation sequence of the different mineral salts that crystallized step by step from the brine during natural evaporation at 30°C was obtained. The results show that the mineral salt precipitation sequence following the saturation data is: sulfates, chlorides, and carbonates. During the evaporative concentration process, the brines become enriched in Na + , K + , HCO3-+ CO3 2-, and depleted in Cland SO4 2with massive halite precipitation. The study provides the basis for the future comprehensive utilization of the natural brine resource in Lake Katwe.
Organic Process Research & Development, 2011
A methodology for the design of cooling crystallization processes for chiral resolution from nonr... more A methodology for the design of cooling crystallization processes for chiral resolution from nonracemic initial solutions is presented. Such processes are encountered when chiral resolution is attained by hybrid processes, where the crystallization step is preceded by a pre-enrichment step accomplished by either asymmetric synthesis or another separation technique. The work focuses on substances that crystallize as conglomerates and accounts for the occurrence of oiling out, i.e., an undesired liquidÀliquid phase separation during crystallization. The generic ternary phase diagrams for conglomerate-forming systems with and without oiling out are derived. This knowledge is then applied to identify suitable operating conditions for chiral resolution. As crystallization is started from saturated solutions, the crystallization process is characterized by three parameters: the initial enantiomeric excess and the initial temperature, which together implicitly define the position of the operating point in the phase diagram, and the final operating temperature, which defines the composition and the amount of the phases present at the end of crystallization. For any initial enantiomeric excess, the methodology yields distinct areas in the initial versus final temperature plane containing pairs of operating temperatures that are suitable for chiral resolution. Such operating map bears great potential in improving the design and optimization of chiral resolution processes by crystallization.
Physics of Fluids, 2006
The hydrodynamic interaction of two neutrally buoyant porous aggregates is investigated under cre... more The hydrodynamic interaction of two neutrally buoyant porous aggregates is investigated under creeping flow conditions for the case where the undisturbed velocity of the surrounding flow field is a linear function of position. In this framework, the relative velocity between two aggregates is given by the deformation of the undisturbed flow expressed through the rate of strain and the angular velocity of the flow field, and by two flow-independent hydrodynamic functions, typically referred to as A and B, which account for the disturbance of the flow field due to the presence of the particles ͓G. K. Batchelor and J. T. Green, J. Fluid Mech. 56, 375 ͑1972͔͒. In the present paper, the analysis of the hydrodynamic interaction that is known for the case of two impermeable, solid particles is extended to the case of porous aggregates by applying Brinkman's equation to describe the flow within the aggregates. A reflection scheme is applied to calculate A and B and the obtained expressions are applied to interpret the orthokinetic aggregation of aggregates in diluted suspensions, where the collision frequency is computed using the method of relative trajectories of a pair of aggregates.
Chemie Ingenieur Technik, 2008
AIChE Journal, 2008
... Matthäus U. Bäbler. Article first published online: 18 APR 2008. DOI: 10.1002/aic.11496. Copy... more ... Matthäus U. Bäbler. Article first published online: 18 APR 2008. DOI: 10.1002/aic.11496. Copyright © 2008 American Institute of Chemical Engineers (AIChE). Issue. AIChE Journal. Volume 54, Issue 7, pages 17481760, July 2008. Additional Information. How to Cite. ...
In monitoring the mean size of clusters during an aggregation-breakup process, it has been repeat... more In monitoring the mean size of clusters during an aggregation-breakup process, it has been repeatedlyobserved that the mean size increases with time to a maximum and then decreases, resulting in an ...
Crystal Growth & Design, 2012
This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. ... more This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. The two enantiomers crystallize as a racemic compound and exhibit a thermodynamically stable liquid–liquid phase separation (LLPS), which extends over the entire enantiomeric composition range. First, the generic phase behavior of racemic compound forming systems exhibiting a stable LLPS is derived by exploiting the consolidated knowledge of conglomerate forming systems obtained in the first part of this series. Below the onset temperature of the LLPS, the system behaves like a typical racemic compound forming system. As for conglomerate forming systems, the onset of the LLPS is found to occur through a ternary monotectic equilibrium, where a new, solute-rich liquid phase emerges inside each solid–solid-liquid phase region. Then, the ternary phase diagram of the ibuprofen/water system in the temperature range from 40 to 82 °C is presented together with the outcome of a thorough experimental investigation. Our ...
Multiphase Flow Phenomena and Applications, 2018
Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbu... more Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence where their breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). T ...
Uganda is well endowed with economic quantities of mineral salts present in the interstitial brin... more Uganda is well endowed with economic quantities of mineral salts present in the interstitial brines and evaporite deposits of Lake Katwe, a closed (endorheic) saline lake located in the western branch of the great East African rift valley. Currently, rudimentally and artisanal methods continue to be used for salt extraction from the lake raw materials. These have proved to be risky and unsustainable to the salt miners and the environment and they have a low productivity and poor product quality. This work involves the investigation of the salt raw materials that naturally occur in the brines and evaporites of Lake Katwe. The purpose is to propose strategies for the extraction of improved salt products for the domestic and commercial industry in Uganda.The literature concerning the occurrence of salt and the most common available technologies for salt extraction was documented. Also, field investigations were undertaken to characterize the salt lake deposits and to assess the salt pr...
Chemical Engineering Science
A hollow core shell model for describing chemisorption of H2S from raw syngas in a packed bed rea... more A hollow core shell model for describing chemisorption of H2S from raw syngas in a packed bed reactor of ZnO
Particle laden flows with reactive particles are common in industrial applications. Chemical reac... more Particle laden flows with reactive particles are common in industrial applications. Chemical reactions inside the particle or deposition at the surface can generate additional flow phenomena that affect the heat, mass and momentum transfer between the particle and bulk flow. This work aims at investigating the effect of Stefan flow on the drag coefficient of a spherical particle immersed in a uniform flow. Fully resolved 3D simulations were carried out for particle Reynolds numbers based on the free stream velocity ranging from 0.5 to 3. Simulations are carried out in foam-extend CFD software, using the Immersed Boundary(IB) method for treating fluid-solid interactions. The simulations were validated against data for particles without reactive flow, and against the analytical solution for Stefan flow around a particle in a quiescent fluid. We found that in the considered range of Reynolds number the drag coefficient decreases linearly with in increase in Stefan flow velocity.
The hydrodynamic breakup of small inertial aggregates in homogenous and isotropic turbulence is s... more The hydrodynamic breakup of small inertial aggregates in homogenous and isotropic turbulence is studied through numerical simulations. Small inertial aggregates are subject to shear stress caused b ...
Industrial & Engineering Chemistry Research, 2021
In this study, NH 3 adsorption isotherms for a commercial vanadium-based SCR catalyst coated on a... more In this study, NH 3 adsorption isotherms for a commercial vanadium-based SCR catalyst coated on a monolith substrate were obtained using a gas flow reactor over a wide range of parameters which have not been performed before in a single study. The isotherms were obtained under different conditions, where adsorption temperature, NH 3 concentration, water concentration, washcoat loading, and catalyst oxidation state were varied. For this purpose, a systematic data processing method was developed, which characterizes the dispersion and delay effects in the experimental setup using a residence time distribution model, and artifacts such as NH 3 adsorbed in the experimental setup and uncertainties in the washcoat loading were removed. As a result, data from different catalyst samples were integrated, and adsorption isotherms with low data spread and well-defined regions were obtained. This allows the identification of the complex nature of the catalyst and dynamics, where multiple types of adsorption sites are present. For instance, the oxidized catalyst has 50% higher NH 3 storage capacity compared to the reduced state of the sample. Moreover, water reduces the NH 3 storage capacity at high concentrations (5.0%), whereas at low concentration (0.5%), water increases the NH 3 adsorption capacity for an oxidized catalyst. The proposed data processing method can be extended for the analysis of further phenomena in catalysts studied using gas flow reactors, complementing current methods and providing information for models with extended validity and lower parameter correlations.
Energy Procedia, 2017
District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.
Energy Procedia, 2017
This work reports the results of the life cycle assessment (LCA) of two carbonation processes aim... more This work reports the results of the life cycle assessment (LCA) of two carbonation processes aimed at permanent CO 2 storage, employing Basic Oxygen Furnace (BOF) slag from steel manufacturing as alkalinity source. Specifically, the performance of the slurry phase and wet carbonation routes were compared assuming to store the CO 2 emitted from a 10 MW conventional natural gas power plant. The LCA was based on the material and energy requirements for each of the involved process steps, i.e. pretreatment and transport of raw materials, CO 2 compression, carbonation, post treatments and management of the obtained products. The slurry and wet route resulted in a net avoided greenhouse warming potential (GWP) of 473 and 384 kg CO 2 /MWh el , respectively. Nevertheless, both routes affected the other environmental impact categories. In general, the wet route had approximately two times higher impact than the slurry route, due in particular to the higher material and energy requirements. An exception was the abiotic resource depletion which resulted higher for the slurry route due to greater water requirement with respect to the wet route. The contributions to all mid-point impact categories were mainly due to energy requirements. A sensitivity analysis showed that the environmental impacts are affected by the energy mix and by the transport distance of slags and carbonation products.
British Journal of Applied Science & Technology, 2015
Lake Katwe is the largest of the eight saline crater lakes in the pleistocene Katwe-Kikorongo vol... more Lake Katwe is the largest of the eight saline crater lakes in the pleistocene Katwe-Kikorongo volcanic field situated in the western arm of the great East African Rift system in southwestern Uganda. The salt lake is hydro-chemically of a carbonate type with its brines representing an important source of mineral salts of high economic value. In the present work, the geochemical simulation of the crystallization route of the natural evaporation of the lake brine in ls was done. The precipitation sequence of the different mineral salts that crystallized step by step from the brine during natural evaporation at 30°C was obtained. The results show that the mineral salt precipitation sequence following the saturation data is: sulfates, chlorides, and carbonates. During the evaporative concentration process, the brines become enriched in Na + , K + , HCO3-+ CO3 2-, and depleted in Cland SO4 2with massive halite precipitation. The study provides the basis for the future comprehensive utilization of the natural brine resource in Lake Katwe.
Organic Process Research & Development, 2011
A methodology for the design of cooling crystallization processes for chiral resolution from nonr... more A methodology for the design of cooling crystallization processes for chiral resolution from nonracemic initial solutions is presented. Such processes are encountered when chiral resolution is attained by hybrid processes, where the crystallization step is preceded by a pre-enrichment step accomplished by either asymmetric synthesis or another separation technique. The work focuses on substances that crystallize as conglomerates and accounts for the occurrence of oiling out, i.e., an undesired liquidÀliquid phase separation during crystallization. The generic ternary phase diagrams for conglomerate-forming systems with and without oiling out are derived. This knowledge is then applied to identify suitable operating conditions for chiral resolution. As crystallization is started from saturated solutions, the crystallization process is characterized by three parameters: the initial enantiomeric excess and the initial temperature, which together implicitly define the position of the operating point in the phase diagram, and the final operating temperature, which defines the composition and the amount of the phases present at the end of crystallization. For any initial enantiomeric excess, the methodology yields distinct areas in the initial versus final temperature plane containing pairs of operating temperatures that are suitable for chiral resolution. Such operating map bears great potential in improving the design and optimization of chiral resolution processes by crystallization.
Physics of Fluids, 2006
The hydrodynamic interaction of two neutrally buoyant porous aggregates is investigated under cre... more The hydrodynamic interaction of two neutrally buoyant porous aggregates is investigated under creeping flow conditions for the case where the undisturbed velocity of the surrounding flow field is a linear function of position. In this framework, the relative velocity between two aggregates is given by the deformation of the undisturbed flow expressed through the rate of strain and the angular velocity of the flow field, and by two flow-independent hydrodynamic functions, typically referred to as A and B, which account for the disturbance of the flow field due to the presence of the particles ͓G. K. Batchelor and J. T. Green, J. Fluid Mech. 56, 375 ͑1972͔͒. In the present paper, the analysis of the hydrodynamic interaction that is known for the case of two impermeable, solid particles is extended to the case of porous aggregates by applying Brinkman's equation to describe the flow within the aggregates. A reflection scheme is applied to calculate A and B and the obtained expressions are applied to interpret the orthokinetic aggregation of aggregates in diluted suspensions, where the collision frequency is computed using the method of relative trajectories of a pair of aggregates.
Chemie Ingenieur Technik, 2008
AIChE Journal, 2008
... Matthäus U. Bäbler. Article first published online: 18 APR 2008. DOI: 10.1002/aic.11496. Copy... more ... Matthäus U. Bäbler. Article first published online: 18 APR 2008. DOI: 10.1002/aic.11496. Copyright © 2008 American Institute of Chemical Engineers (AIChE). Issue. AIChE Journal. Volume 54, Issue 7, pages 17481760, July 2008. Additional Information. How to Cite. ...
In monitoring the mean size of clusters during an aggregation-breakup process, it has been repeat... more In monitoring the mean size of clusters during an aggregation-breakup process, it has been repeatedlyobserved that the mean size increases with time to a maximum and then decreases, resulting in an ...
Crystal Growth & Design, 2012
This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. ... more This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. The two enantiomers crystallize as a racemic compound and exhibit a thermodynamically stable liquid–liquid phase separation (LLPS), which extends over the entire enantiomeric composition range. First, the generic phase behavior of racemic compound forming systems exhibiting a stable LLPS is derived by exploiting the consolidated knowledge of conglomerate forming systems obtained in the first part of this series. Below the onset temperature of the LLPS, the system behaves like a typical racemic compound forming system. As for conglomerate forming systems, the onset of the LLPS is found to occur through a ternary monotectic equilibrium, where a new, solute-rich liquid phase emerges inside each solid–solid-liquid phase region. Then, the ternary phase diagram of the ibuprofen/water system in the temperature range from 40 to 82 °C is presented together with the outcome of a thorough experimental investigation. Our ...
Multiphase Flow Phenomena and Applications, 2018
Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbu... more Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence where their breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). T ...
Uganda is well endowed with economic quantities of mineral salts present in the interstitial brin... more Uganda is well endowed with economic quantities of mineral salts present in the interstitial brines and evaporite deposits of Lake Katwe, a closed (endorheic) saline lake located in the western branch of the great East African rift valley. Currently, rudimentally and artisanal methods continue to be used for salt extraction from the lake raw materials. These have proved to be risky and unsustainable to the salt miners and the environment and they have a low productivity and poor product quality. This work involves the investigation of the salt raw materials that naturally occur in the brines and evaporites of Lake Katwe. The purpose is to propose strategies for the extraction of improved salt products for the domestic and commercial industry in Uganda.The literature concerning the occurrence of salt and the most common available technologies for salt extraction was documented. Also, field investigations were undertaken to characterize the salt lake deposits and to assess the salt pr...