Elisabetta Brunazzi - Profile on Academia.edu (original) (raw)
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Papers by Elisabetta Brunazzi
Undesired aerosol formation in gas–liquid contact devices like for instance absorbers, quench coo... more Undesired aerosol formation in gas–liquid contact devices like for instance absorbers, quench coolers, or condensers, causes severe complications in industrial processes. Gas-liquid coalescing filter media, normally called fiber beds or candles filters, have received great attention in a wide variety of industrial applications, being a removal technology with one of the highest achievable droplet removal efficiency for submicron particles. This work deals with a novel multi-layer fiber bed, the GX mist eliminator, developed by AWS Corporation srl with improved performances compared to the conventional single-layer fiber bed commercialized by the Company. The novel fiber bed was conceived by means of a developed design model that takes into account constructional and operating parameters. The model was validated by experiments carried out on a lab scale unit. The performances of the novel fiber bed were then validated by experiments carried out in a pilot plant installed on a product...
Biomethane production: Mass and Energy Balances of Alternative Supply Chains
Industrial & Engineering Chemistry Research
Two supply chains for biomethane are here analyzed and modeled: gasification of short rotation fo... more Two supply chains for biomethane are here analyzed and modeled: gasification of short rotation forestry (SRF) poplar wood chips and anaerobic digestion of two species of microalgae, Chlorella vulgaris, and Nannochloropsis gaditana. Mass and energy balances are carried out along the whole systems, from the cultivation step to the stages of upgrading and injection into gas grid. A simulation model is employed to obtain gasification and upgrading parameters, energy requirements, and CO2 emission. Harvesting of microalgae requires high inputs of energy and fertilizers, while syngas upgrading is more demanding than biogas treatment, as high volumes of water and CO2 must be separated. Yields of the supply chains are very different: 7:1 biomethane:syngas ratio and 2:1 biomethane:biogas ratio have been estimated. Both of the supply chains could be optimized by using heat recovery methods. The highest removal of CO2 and steam can be attained through absorption by triethylene and monoethanolamine solution, respecti...
Laser Doppler anemometry and flow visualisation are used to shed light into the main turbulent fl... more Laser Doppler anemometry and flow visualisation are used to shed light into the main turbulent flow features of an unbaffled vessel stirred by an eccentrically positioned Rushton turbine. Two main vortices, one above and one below the impeller, are present and the former vortex dominates the flow field, driving a strong circumferential flow around it. The vortices are not steady but oscillate slowly and periodically inducing a kind of flow instabilities, which may have a significant impact on macro-mixing. The characteristic frequencies of such flow instabilities were found to increase with reducing the impeller blade thickness, thus it is argued that their origin is related to the interaction between the impeller discharged stream and the vessel wall/bottom. 1.
Special Issue Distillation and Absorption
Rottura della simmetria in un micro-mescolatore a T
This paper presents the results of an experimental study carried out to examine the hydraulic beh... more This paper presents the results of an experimental study carried out to examine the hydraulic behaviour of Katapak-SP11, a new structured catalytic packing of Sulzer Chemtech. Liquid holdup, dry and wet pressure drop, gas capacity and loading of two sizes of packing have been measured using the air-water system at ambient conditions. The experimental results collected are useful for supporting theoretical developments in hydrodynamic modelling and analysis of scale up issues. Data have been used to derive a set of correlation equations to describe the above quantities in terms of gas and liquid loads.
Experimental and numerical analyses of unsteady flow regimes and mixing in a micro T-mixer
Unsteady flow features in a T-shaped micro-mixer
Flow transitions and instabilities stemming from clearance variations in stirred vessels. Paper to be presented to the ICheaP-6
Modern catalytic structured packings offer a uniform catalyst support where catalyst particles ca... more Modern catalytic structured packings offer a uniform catalyst support where catalyst particles can be embedded thus combining its features with the well-known advantages of a structured packing (high capacity and high mass-transfer efficiency). In this work, the hydrodynamic properties of a novel family of catalytic structured packings (KATAPAK-SP) have been modeled using a modified version of a hydraulic model originally proposed by Hoffmann et al. for MULTIPAK. Modifications to the model included: (1) the adaptation of a more suitable liquid holdup correlation for the open channels, and (2) the use of a different split factor for the liquid flowing through the catalyst bags and the open channels. 1. Hoffmann et al., Chem. Eng. Proc., 43, 383 (2004).
Implementation of an Industry 4.0 system to optimally manage chemical plant operation
IFAC-PapersOnLine
Chemical Engineering Journal
Despite the very simple geometry, T-shaped micro-mixers are characterized by different flow regim... more Despite the very simple geometry, T-shaped micro-mixers are characterized by different flow regimes when operated for liquid mixing. In this work, experiments and direct numerical simulations are employed jointly to investigate such flow regimes. First, a novel methodology is proposed to provide a quantitative comparison with numerical predictions starting from simple flow visualization experiments that use non-collimated light. This method is applied and validated in the steady flow regimes. Moreover, flow visualizations provide for the first time an experimental support to the flow dynamics scenarios for the periodic unsteady flow regimes previously proposed in the literature on the basis of numerical simulations. In particular, at a Reynolds number, based on the bulk velocity and on the hydraulic diameter of the mixing channel, of approximately 225, the flow passes from the steady engulfment regime into an unsteady asymmetric regime, which is characterized by a periodic dynamics of the three-dimensional structures present in the mixer. In this regime, the flow in the mixing channel always remains asymmetric promoting, thus, the mixing between the two streams. By further increasing the Reynolds number, another change in flow dynamics is observed. In the new regime, called periodic symmet
This paper presents the results of an experimental study carried out to examine liquid holdup in ... more This paper presents the results of an experimental study carried out to examine liquid holdup in 100 mm diameter catalytic structured packing Katapak-SP. Two versions of the packing have been investigated. Both global and local measurements were carried out on the very same packings, using water at ambient conditions as working liquid. To this scope, traditional methods like draining techniques were used to obtain global holdup values. A non-intrusive high energy X-ray tomography was used for gathering information on local scale and study axial distribution of the liquid holdup over the packed column, inside and outside the catalyst containing baskets. The total liquid holdup of the catalytic packed bed was evaluated by averaging holdup values obtained at different cross sections over the corresponding volume. Very good agreement was found between global values estimated with the different techniques. The experimental results are useful for supporting theoretical developments in hydrodynamic and mass transfer modeling.
On the problems of solvent recovery from printing processes
Optimized design of obstacle sequences for microfluidic mixing in an inertial regime
Lab on a Chip
A fast method for designing optimal sequences of passive mixing units is provided for inertial fl... more A fast method for designing optimal sequences of passive mixing units is provided for inertial flows. Intense mixing is achieved through highly-controlled stretching of the fluid contact surfaces.
Micromachines
Despite the very simple geometry and the laminar flow, T-shaped microreactors have been found to ... more Despite the very simple geometry and the laminar flow, T-shaped microreactors have been found to be characterized by different and complex steady and unsteady flow regimes, depending on the Reynolds number. In particular, flow unsteadiness modifies strongly the mixing process; however, little is known on how this change may affect the yield of a chemical reaction. In the present work, experiments and 3-dimensional numerical simulations are carried out jointly to analyze mixing and reaction in a T-shaped microreactor with the ultimate goal to investigate how flow unsteadiness affects the reaction yield. The onset of the unsteady asymmetric regime enhances the reaction yield by more than 30%; however, a strong decrease of the yield back to values typical of the vortex regime is observed when the flow undergoes a transition to the unsteady symmetric regime.
The role of flow features and chemical kinetics on the reaction yield in a T-shaped micro-reactor
Chemical Engineering Journal
A multi-layered view of chemical and biochemical engineering
Chemical Engineering Research and Design
Industrial & Engineering Chemistry Research
Updating industrial facilities to increase the level of automation and digitalization to match In... more Updating industrial facilities to increase the level of automation and digitalization to match Industry 4.0 paradigms has become essential for many companies. Following such a trend, this paper presents a real-time optimization algorithm that plays a central role in a larger project framework devoted to highly interconnecting different network components of an Italian chemical industrial site. The proposed methodology aims at best managing the production rates of various products to fulfill a sales plan organized to satisfy numerous client requests. The considered model takes into account both batch and continuous processes as well as salable and non-storable products. The algorithm structure relies on the use of a non-linear optimization scheme and on the concepts of batch scheduling. Different features of the proposed methodology have been tested on real plant data, showing how the predicted forecast always improved the initial operation plan by considering both aspects of feasibility and economic nature. The use of the proposed algorithm assures the basis for fully integrating the control systems and the selling department of the facility in a more interactive and responsive manner.
Unsteady flow regimes in a T-shaped micro-mixer: mixing and characteristic frequencies
Industrial & Engineering Chemistry Research
Undesired aerosol formation in gas–liquid contact devices like for instance absorbers, quench coo... more Undesired aerosol formation in gas–liquid contact devices like for instance absorbers, quench coolers, or condensers, causes severe complications in industrial processes. Gas-liquid coalescing filter media, normally called fiber beds or candles filters, have received great attention in a wide variety of industrial applications, being a removal technology with one of the highest achievable droplet removal efficiency for submicron particles. This work deals with a novel multi-layer fiber bed, the GX mist eliminator, developed by AWS Corporation srl with improved performances compared to the conventional single-layer fiber bed commercialized by the Company. The novel fiber bed was conceived by means of a developed design model that takes into account constructional and operating parameters. The model was validated by experiments carried out on a lab scale unit. The performances of the novel fiber bed were then validated by experiments carried out in a pilot plant installed on a product...
Biomethane production: Mass and Energy Balances of Alternative Supply Chains
Industrial & Engineering Chemistry Research
Two supply chains for biomethane are here analyzed and modeled: gasification of short rotation fo... more Two supply chains for biomethane are here analyzed and modeled: gasification of short rotation forestry (SRF) poplar wood chips and anaerobic digestion of two species of microalgae, Chlorella vulgaris, and Nannochloropsis gaditana. Mass and energy balances are carried out along the whole systems, from the cultivation step to the stages of upgrading and injection into gas grid. A simulation model is employed to obtain gasification and upgrading parameters, energy requirements, and CO2 emission. Harvesting of microalgae requires high inputs of energy and fertilizers, while syngas upgrading is more demanding than biogas treatment, as high volumes of water and CO2 must be separated. Yields of the supply chains are very different: 7:1 biomethane:syngas ratio and 2:1 biomethane:biogas ratio have been estimated. Both of the supply chains could be optimized by using heat recovery methods. The highest removal of CO2 and steam can be attained through absorption by triethylene and monoethanolamine solution, respecti...
Laser Doppler anemometry and flow visualisation are used to shed light into the main turbulent fl... more Laser Doppler anemometry and flow visualisation are used to shed light into the main turbulent flow features of an unbaffled vessel stirred by an eccentrically positioned Rushton turbine. Two main vortices, one above and one below the impeller, are present and the former vortex dominates the flow field, driving a strong circumferential flow around it. The vortices are not steady but oscillate slowly and periodically inducing a kind of flow instabilities, which may have a significant impact on macro-mixing. The characteristic frequencies of such flow instabilities were found to increase with reducing the impeller blade thickness, thus it is argued that their origin is related to the interaction between the impeller discharged stream and the vessel wall/bottom. 1.
Special Issue Distillation and Absorption
Rottura della simmetria in un micro-mescolatore a T
This paper presents the results of an experimental study carried out to examine the hydraulic beh... more This paper presents the results of an experimental study carried out to examine the hydraulic behaviour of Katapak-SP11, a new structured catalytic packing of Sulzer Chemtech. Liquid holdup, dry and wet pressure drop, gas capacity and loading of two sizes of packing have been measured using the air-water system at ambient conditions. The experimental results collected are useful for supporting theoretical developments in hydrodynamic modelling and analysis of scale up issues. Data have been used to derive a set of correlation equations to describe the above quantities in terms of gas and liquid loads.
Experimental and numerical analyses of unsteady flow regimes and mixing in a micro T-mixer
Unsteady flow features in a T-shaped micro-mixer
Flow transitions and instabilities stemming from clearance variations in stirred vessels. Paper to be presented to the ICheaP-6
Modern catalytic structured packings offer a uniform catalyst support where catalyst particles ca... more Modern catalytic structured packings offer a uniform catalyst support where catalyst particles can be embedded thus combining its features with the well-known advantages of a structured packing (high capacity and high mass-transfer efficiency). In this work, the hydrodynamic properties of a novel family of catalytic structured packings (KATAPAK-SP) have been modeled using a modified version of a hydraulic model originally proposed by Hoffmann et al. for MULTIPAK. Modifications to the model included: (1) the adaptation of a more suitable liquid holdup correlation for the open channels, and (2) the use of a different split factor for the liquid flowing through the catalyst bags and the open channels. 1. Hoffmann et al., Chem. Eng. Proc., 43, 383 (2004).
Implementation of an Industry 4.0 system to optimally manage chemical plant operation
IFAC-PapersOnLine
Chemical Engineering Journal
Despite the very simple geometry, T-shaped micro-mixers are characterized by different flow regim... more Despite the very simple geometry, T-shaped micro-mixers are characterized by different flow regimes when operated for liquid mixing. In this work, experiments and direct numerical simulations are employed jointly to investigate such flow regimes. First, a novel methodology is proposed to provide a quantitative comparison with numerical predictions starting from simple flow visualization experiments that use non-collimated light. This method is applied and validated in the steady flow regimes. Moreover, flow visualizations provide for the first time an experimental support to the flow dynamics scenarios for the periodic unsteady flow regimes previously proposed in the literature on the basis of numerical simulations. In particular, at a Reynolds number, based on the bulk velocity and on the hydraulic diameter of the mixing channel, of approximately 225, the flow passes from the steady engulfment regime into an unsteady asymmetric regime, which is characterized by a periodic dynamics of the three-dimensional structures present in the mixer. In this regime, the flow in the mixing channel always remains asymmetric promoting, thus, the mixing between the two streams. By further increasing the Reynolds number, another change in flow dynamics is observed. In the new regime, called periodic symmet
This paper presents the results of an experimental study carried out to examine liquid holdup in ... more This paper presents the results of an experimental study carried out to examine liquid holdup in 100 mm diameter catalytic structured packing Katapak-SP. Two versions of the packing have been investigated. Both global and local measurements were carried out on the very same packings, using water at ambient conditions as working liquid. To this scope, traditional methods like draining techniques were used to obtain global holdup values. A non-intrusive high energy X-ray tomography was used for gathering information on local scale and study axial distribution of the liquid holdup over the packed column, inside and outside the catalyst containing baskets. The total liquid holdup of the catalytic packed bed was evaluated by averaging holdup values obtained at different cross sections over the corresponding volume. Very good agreement was found between global values estimated with the different techniques. The experimental results are useful for supporting theoretical developments in hydrodynamic and mass transfer modeling.
On the problems of solvent recovery from printing processes
Optimized design of obstacle sequences for microfluidic mixing in an inertial regime
Lab on a Chip
A fast method for designing optimal sequences of passive mixing units is provided for inertial fl... more A fast method for designing optimal sequences of passive mixing units is provided for inertial flows. Intense mixing is achieved through highly-controlled stretching of the fluid contact surfaces.
Micromachines
Despite the very simple geometry and the laminar flow, T-shaped microreactors have been found to ... more Despite the very simple geometry and the laminar flow, T-shaped microreactors have been found to be characterized by different and complex steady and unsteady flow regimes, depending on the Reynolds number. In particular, flow unsteadiness modifies strongly the mixing process; however, little is known on how this change may affect the yield of a chemical reaction. In the present work, experiments and 3-dimensional numerical simulations are carried out jointly to analyze mixing and reaction in a T-shaped microreactor with the ultimate goal to investigate how flow unsteadiness affects the reaction yield. The onset of the unsteady asymmetric regime enhances the reaction yield by more than 30%; however, a strong decrease of the yield back to values typical of the vortex regime is observed when the flow undergoes a transition to the unsteady symmetric regime.
The role of flow features and chemical kinetics on the reaction yield in a T-shaped micro-reactor
Chemical Engineering Journal
A multi-layered view of chemical and biochemical engineering
Chemical Engineering Research and Design
Industrial & Engineering Chemistry Research
Updating industrial facilities to increase the level of automation and digitalization to match In... more Updating industrial facilities to increase the level of automation and digitalization to match Industry 4.0 paradigms has become essential for many companies. Following such a trend, this paper presents a real-time optimization algorithm that plays a central role in a larger project framework devoted to highly interconnecting different network components of an Italian chemical industrial site. The proposed methodology aims at best managing the production rates of various products to fulfill a sales plan organized to satisfy numerous client requests. The considered model takes into account both batch and continuous processes as well as salable and non-storable products. The algorithm structure relies on the use of a non-linear optimization scheme and on the concepts of batch scheduling. Different features of the proposed methodology have been tested on real plant data, showing how the predicted forecast always improved the initial operation plan by considering both aspects of feasibility and economic nature. The use of the proposed algorithm assures the basis for fully integrating the control systems and the selling department of the facility in a more interactive and responsive manner.
Unsteady flow regimes in a T-shaped micro-mixer: mixing and characteristic frequencies
Industrial & Engineering Chemistry Research