Abdelghafour Zaabout - Profile on Academia.edu (original) (raw)

Papers by Abdelghafour Zaabout

Research paper thumbnail of Experimental investigation of the effect of gas permeation through vertical membrane on the onset of transition velocity from bubbling to turbulent regime in fluidized bed

Membrane-assisted (MA) fluidized beds have recently emerged as a cutting-edge technology for inte... more Membrane-assisted (MA) fluidized beds have recently emerged as a cutting-edge technology for intensification of a number of industrial chemical processes. MA-fluidized bed reactors combine the benefits of the separation properties of membranes and the advantages of fluidized bed reactors known for their excellent heat and mass transport characteristics; the presence of membranes maximises the volumetric production rate by reducing equilibrium limitations. Hydrogen production from methane reforming is one of the main applications of MA-fluidized beds. Particularly, the Chemical Switching Reforming (CSR) (figure 1) reactor concept has recently been introduced as a promising reactor concept for cost effective pure hydrogen production from steam-methane reforming with integrated CO2 separation. CSR operates under transient behaviour where methane/steam and air are alternatively fed into a single reactor with a bed of oxygen carrier material (which acts both as a catalyst and heat carrie...

Research paper thumbnail of A novel gas switching combustion reactor for power production with integrated CO2 capture: sensitivity to the fuel type

This paper reports further experimental demonstration of the Gas Switching Combustion (GSC) conce... more This paper reports further experimental demonstration of the Gas Switching Combustion (GSC) concept with a focus on the concept sensitivity to the fuel type. The GSC concept offers an alternative to the conventional chemical looping combustion (CLC) process for power production with integrated CO2 capture. In this concept, oxidation and reduction of the oxygen carrier take place in the same reactor by alternating air and fuel gas feeds into the reactor. This completely avoids any need for oxygen carrier circulation and thereby avoids many technical and scale-up challenges related to the looping concept. First demonstration of the concept with carbon monoxide (CO) as reducing gas and Ni-based oxygen carrier showed that the reactor could operate autothermally to continuously convert cold feed gases into hot product gases. In this paper, the GSC concept is further tested with syngas and methane as reducing gases. First testing of the reactor with carbon monoxide showed large heat losse...

Research paper thumbnail of Hydrogen : Key to flexible energy systems with CO2 Capture

Hydrogen : Key to flexible energy systems with CO2 Capture

Research paper thumbnail of An assessment of the ability of the TFM approach to predict gas mixing in a pseudo-2D bubbling fluidized bed

2D and 3D simulations of gas species diffusion in a pseudo-2D bubbling fluidized bed were carried... more 2D and 3D simulations of gas species diffusion in a pseudo-2D bubbling fluidized bed were carried out and compared to experimental measurements. Tracer gas concentration and solids velocity profiles measured throughout the bed showed great deviations of the 2D simulations due to negligence of the friction on the large front and back walls of the pseudo-2D unit and the inability to resolve gas species gradients across the thickness of the bed. 3D simulations circumvent these limitations and result in much more reasonable comparisons with experimental data. A clear lack of gas species diffusion was observed, however, and this was attributed to the negligence of particle-induced diffusion of gas species within the bed. Further work is recommended to investigate the modelling of particle-induced gas species diffusion in fluidized bed reactors.

Research paper thumbnail of Internally circulating fluidized-bed reactor for hydrogen production with inherent CO2 capture using chemical looping reforming

Chemical looping reforming of natural gas is one of the most promising technologies for hydrogen ... more Chemical looping reforming of natural gas is one of the most promising technologies for hydrogen production with inherent CO2 capture on terms of efficiency and economy. Pressurized operation of chemical looping based processes is necessary for maximizing their energy efficiency especially when it used for power production with combined cycle operation, and it reduces the energy penalty for H2 and CO2 compression. However, there are many challenges facing the pressurized operation of the conventional dual fluidized-bed reactor. This study provides the prospects and opportunities that exist for novel application of the internally circulating reactor (ICR) to be used for pressurized chemical looping reforming.

Research paper thumbnail of Characterization of turbulent regime behavior in the dilute zone of a circulating fluidized bed riser

This study consists in characterizing the solid phase behavior in the dilute region of a circulat... more This study consists in characterizing the solid phase behavior in the dilute region of a circulating fluidized bed riser (CFB) for the turbulent regime (i.e. for superficial gas velocities U c <U g <U k). Two sizes of particles (109 µm and 175 µm), and different static bed heights H s (50 mm, 100 mm and 150 mm) for each distribution of particle, have been studied. Transition velocities U c and U k , which delimit the turbulent regime are determined from the standard deviation of the absolute pressure, and were found to increase with increasing H s and not depend on axial positions. Radial profiles of the mean axial and transversal velocities have been determined with a PDA instrument. Two shapes of axial velocity profile (parabolic and concave) have been identified for the first distribution of particles (small particles). The shape is found to depend on the static bed height and the superficial gas velocity. Parabolic profiles were always found for the second distribution (large particles). The transversal velocities show that the particles move toward the riser center for small static bed heights H s in the turbulent regime. This movement change toward the wall with increasing H s, especially in the near wall region. More attention has been paid to the fluctuating character of the solid phase in analyzing the standard deviation of the mean axial and transversal particle velocities.

Research paper thumbnail of Kinetic characterization of the fuel stage of the chemical switching reforming proces through TGA-MS studies

Kinetic characterization of the fuel stage of the chemical switching reforming proces through TGA-MS studies

Research paper thumbnail of The effect of gas extraction through vertical membranes on the bubble hydrodynamics in a fluidized bed reactor

The effect of gas extraction through vertical membranes on the bubble hydrodynamics in a fluidized bed reactor

Research paper thumbnail of Characterization of Turbulent Regime Behavior in the Dilute Zone of a Circulating Fluidized Bed Riser

This study consists in characterizing the solid phase behavior in the dilute region of a circulat... more This study consists in characterizing the solid phase behavior in the dilute region of a circulating fluidized bed riser (CFB) for the turbulent regime (i.e. for superficial gas velocities U c <U g <U k). Two sizes of particles (109 µm and 175 µm), and different static bed heights H s (50 mm, 100 mm and 150 mm) for each distribution of particle, have been studied. Transition velocities U c and U k , which delimit the turbulent regime are determined from the standard deviation of the absolute pressure, and were found to increase with increasing H s and not depend on axial positions. Radial profiles of the mean axial and transversal velocities have been determined with a PDA instrument. Two shapes of axial velocity profile (parabolic and concave) have been identified for the first distribution of particles (small particles). The shape is found to depend on the static bed height and the superficial gas velocity. Parabolic profiles were always found for the second distribution (large particles). The transversal velocities show that the particles move toward the riser center for small static bed heights H s in the turbulent regime. This movement change toward the wall with increasing H s, especially in the near wall region. More attention has been paid to the fluctuating character of the solid phase in analyzing the standard deviation of the mean axial and transversal particle velocities.

Research paper thumbnail of Optimal particle parameters for CLC and CLR processes - predictions by intra-particle transport models and experimental validation

Validated models for predicting oxidation and reduction kinetics of multi-component porous partic... more Validated models for predicting oxidation and reduction kinetics of multi-component porous particles in chemical looping combustion (CLC) and chemical looping combustion (CLC) processes are of key importance to identify the rate limiting in these processes. Since particle properties (i.e., their composition, porosity, pore size, grain size, etc.) can be adjusted by modern synthesis techniques, there is an open question on the optimal set of these properties that would lead to the most economic process. In this study we present an overview of recent developments [1,2] in the field of continuum and shrinking-core-type intra-particle models. We then introduce a general open-source simulation environment, called ParScale, that can be used to simulate models relevant for CLC and CLR processes. Most important, ParScale features a generalized one-dimensional spherical discretization which enables the user to predict an arbitrary number of reactions within non-isothermal porous particles co...

Research paper thumbnail of Combined Syngas and Hydrogen Production using Gas Switching Technology

Industrial & Engineering Chemistry Research

This paper focuses on the experimental demonstration of a threestage GST (gas switching technolog... more This paper focuses on the experimental demonstration of a threestage GST (gas switching technology) process (fuel, steam/CO 2 , and air stages) for syngas production from methane in the fuel stage and H 2 /CO production in the steam/CO 2 stage using a lanthanum-based oxygen carrier (La 0.85 Sr 0.15 Fe 0.95 Al 0.05 O 3). Experiments were performed at temperatures between 750−950°C and pressures up to 5 bar. The results show that the oxygen carrier exhibits high selectivity to oxidizing methane to syngas at the fuel stage with improved process performance with increasing temperature although carbon deposition could not be avoided. Co-feeding CO 2 with CH 4 at the fuel stage reduced carbon deposition significantly, thus reducing the syngas H 2 /CO molar ratio from 3.75 to 1 (at CO 2 /CH 4 ratio of 1 at 950°C and 1 bar). The reduced carbon deposition has maximized the purity of the H 2 produced in the consecutive steam stage thus increasing the process attractiveness for the combined production of syngas and pure hydrogen. Interestingly, the cofeeding of CO 2 with CH 4 at the fuel stage showed a stable syngas production over 12 hours continuously and maintained the H 2 /CO ratio at almost unity, suggesting that the oxygen carrier was exposed to simultaneous partial oxidation of CH 4 with the lattice oxygen which was restored instantly by the incoming CO 2. Furthermore, the addition of steam to the fuel stage could tune up the H 2 /CO ratio beyond 3 without carbon deposition at H 2 O/ CH 4 ratio of 1 at 950°C and 1 bar; making the syngas from gas switching partial oxidation suitable for different downstream processes, for example, gas-to-liquid processes. The process was also demonstrated at higher pressures with over 70% fuel conversion achieved at 5 bar and 950°C.

Research paper thumbnail of Pressurized chemical looping methane reforming to syngas for efficient methanol production: experimental and process simulation study

Pressurized chemical looping methane reforming to syngas for efficient methanol production: experimental and process simulation study

Advances in Applied Energy

Research paper thumbnail of Study of the Cost Reductions Achievable from the Novel SARC CO2 Capture Concept Using a Validated Reactor Model

Industrial & Engineering Chemistry Research

New process concepts, such as the swing adsorption reactor cluster (SARC) CO 2 capture process, a... more New process concepts, such as the swing adsorption reactor cluster (SARC) CO 2 capture process, are often technoeconomically investigated using idealized modeling assumptions. This study quantifies the impact of this practice by updating a previous economic assessment with results from an improved reactor model validated against recently completed SARC lab-scale demonstration experiments. The experimental comparison showed that the assumption of chemical equilibrium was valid, that the previously employed heat transfer coefficient was conservatively low, and that the required reduction of axial mixing could be easily achieved using simple perforated plates in the reactor. However, the assumption of insignificant effects of the hydrostatic pressure gradient needed to be revised. In the economic assessment, the negative effect of the hydrostatic pressure gradient was almost canceled out by deploying the experimentally observed heat transfer coefficients, resulting in a small net increase in CO 2 avoidance costs of 2.8−4.8% relative to the unvalidated model. Further reductions in axial mixing via more perforated plates only brought minor benefits, but a shorter reactor enabled by the fast experimentally observed adsorption kinetics had a larger positive effect: halving the reactor height reduced CO 2 avoidance costs by 13.3%. A new heat integration scheme feeding vacuum pressure steam raised from several low-grade heat sources to the SARC desorption step resulted in similar gains. When all improvements were combined, the optimal CO 2 avoidance cost was 23.7% below the best result from prior works. The main uncertainty that needs to be overcome to realize the great economic potential of the SARC concept is long-term sorbent stability: mechanical stability must be improved substantially and long-term chemical stability under real flue gas conditions must be demonstrated.

Research paper thumbnail of Hydrogen production by water splitting using gas switching technology

Hydrogen production by water splitting using gas switching technology

Powder Technology

Research paper thumbnail of Demonstration of the Novel Swing Adsorption Reactor Cluster Concept in a Multistage Fluidized Bed with Heat-Transfer Surfaces for Postcombustion CO2 Capture

Demonstration of the Novel Swing Adsorption Reactor Cluster Concept in a Multistage Fluidized Bed with Heat-Transfer Surfaces for Postcombustion CO2 Capture

Industrial & Engineering Chemistry Research

Research paper thumbnail of Review on Reactor Configurations for Adsorption-Based CO2 Capture

Industrial & Engineering Chemistry Research

Adsorption-based CO 2 capture has enjoyed considerable research attention in recent years. Most o... more Adsorption-based CO 2 capture has enjoyed considerable research attention in recent years. Most of the research efforts focused on sorbent development to reduce the energy penalty. However, the use of suitable gas−solid contacting systems is key for extracting the full potential from the sorbent to minimize operating and capital costs and accelerate the commercial deployment of the technology. This paper reviews several reactor configurations that were proposed for adsorptionbased CO 2 capture. The fundamental behavior of adsorption in different gas−solid contactors (fixed, fluidized, moving, or rotating beds) and regeneration under different modes (pressure, temperature, or combined swings) is discussed, highlighting the strengths and limitations of different combinations of gas−solid contactor and regeneration mode. In addition, the estimated energy duties in published studies and current technology readiness level of the different reactor configurations are reported. Other aspects, such as the reactor footprint, the operation strategy, suitability to retrofits, and the ability to operate under flexible loads are also discussed. In terms of future work, the key research need is a standardized techno-economic benchmarking study to calculate CO 2 avoidance costs for different adsorption technologies under standardized assumptions. Qualitatively, each technology presents several strengths and weaknesses that make it impossible to identify a clear optimal solution. Such a standardized quantitative comparison is therefore needed to focus on future technology development efforts.

Research paper thumbnail of Review of pressurized chemical looping processes for power generation and chemical production with integrated CO2 capture

Review of pressurized chemical looping processes for power generation and chemical production with integrated CO2 capture

Fuel Processing Technology

Research paper thumbnail of Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

Chemical Engineering Journal

Research paper thumbnail of The effect of sorbent regeneration enthalpy on the performance of the novel Swing Adsorption Reactor Cluster (SARC) for post-combustion CO2 capture

The effect of sorbent regeneration enthalpy on the performance of the novel Swing Adsorption Reactor Cluster (SARC) for post-combustion CO2 capture

Chemical Engineering Journal

Research paper thumbnail of Mapping the operating performance of a novel internally circulating fluidized bed reactor applied to chemical looping combustion

Mapping the operating performance of a novel internally circulating fluidized bed reactor applied to chemical looping combustion

Fuel Processing Technology

Research paper thumbnail of Experimental investigation of the effect of gas permeation through vertical membrane on the onset of transition velocity from bubbling to turbulent regime in fluidized bed

Membrane-assisted (MA) fluidized beds have recently emerged as a cutting-edge technology for inte... more Membrane-assisted (MA) fluidized beds have recently emerged as a cutting-edge technology for intensification of a number of industrial chemical processes. MA-fluidized bed reactors combine the benefits of the separation properties of membranes and the advantages of fluidized bed reactors known for their excellent heat and mass transport characteristics; the presence of membranes maximises the volumetric production rate by reducing equilibrium limitations. Hydrogen production from methane reforming is one of the main applications of MA-fluidized beds. Particularly, the Chemical Switching Reforming (CSR) (figure 1) reactor concept has recently been introduced as a promising reactor concept for cost effective pure hydrogen production from steam-methane reforming with integrated CO2 separation. CSR operates under transient behaviour where methane/steam and air are alternatively fed into a single reactor with a bed of oxygen carrier material (which acts both as a catalyst and heat carrie...

Research paper thumbnail of A novel gas switching combustion reactor for power production with integrated CO2 capture: sensitivity to the fuel type

This paper reports further experimental demonstration of the Gas Switching Combustion (GSC) conce... more This paper reports further experimental demonstration of the Gas Switching Combustion (GSC) concept with a focus on the concept sensitivity to the fuel type. The GSC concept offers an alternative to the conventional chemical looping combustion (CLC) process for power production with integrated CO2 capture. In this concept, oxidation and reduction of the oxygen carrier take place in the same reactor by alternating air and fuel gas feeds into the reactor. This completely avoids any need for oxygen carrier circulation and thereby avoids many technical and scale-up challenges related to the looping concept. First demonstration of the concept with carbon monoxide (CO) as reducing gas and Ni-based oxygen carrier showed that the reactor could operate autothermally to continuously convert cold feed gases into hot product gases. In this paper, the GSC concept is further tested with syngas and methane as reducing gases. First testing of the reactor with carbon monoxide showed large heat losse...

Research paper thumbnail of Hydrogen : Key to flexible energy systems with CO2 Capture

Hydrogen : Key to flexible energy systems with CO2 Capture

Research paper thumbnail of An assessment of the ability of the TFM approach to predict gas mixing in a pseudo-2D bubbling fluidized bed

2D and 3D simulations of gas species diffusion in a pseudo-2D bubbling fluidized bed were carried... more 2D and 3D simulations of gas species diffusion in a pseudo-2D bubbling fluidized bed were carried out and compared to experimental measurements. Tracer gas concentration and solids velocity profiles measured throughout the bed showed great deviations of the 2D simulations due to negligence of the friction on the large front and back walls of the pseudo-2D unit and the inability to resolve gas species gradients across the thickness of the bed. 3D simulations circumvent these limitations and result in much more reasonable comparisons with experimental data. A clear lack of gas species diffusion was observed, however, and this was attributed to the negligence of particle-induced diffusion of gas species within the bed. Further work is recommended to investigate the modelling of particle-induced gas species diffusion in fluidized bed reactors.

Research paper thumbnail of Internally circulating fluidized-bed reactor for hydrogen production with inherent CO2 capture using chemical looping reforming

Chemical looping reforming of natural gas is one of the most promising technologies for hydrogen ... more Chemical looping reforming of natural gas is one of the most promising technologies for hydrogen production with inherent CO2 capture on terms of efficiency and economy. Pressurized operation of chemical looping based processes is necessary for maximizing their energy efficiency especially when it used for power production with combined cycle operation, and it reduces the energy penalty for H2 and CO2 compression. However, there are many challenges facing the pressurized operation of the conventional dual fluidized-bed reactor. This study provides the prospects and opportunities that exist for novel application of the internally circulating reactor (ICR) to be used for pressurized chemical looping reforming.

Research paper thumbnail of Characterization of turbulent regime behavior in the dilute zone of a circulating fluidized bed riser

This study consists in characterizing the solid phase behavior in the dilute region of a circulat... more This study consists in characterizing the solid phase behavior in the dilute region of a circulating fluidized bed riser (CFB) for the turbulent regime (i.e. for superficial gas velocities U c <U g <U k). Two sizes of particles (109 µm and 175 µm), and different static bed heights H s (50 mm, 100 mm and 150 mm) for each distribution of particle, have been studied. Transition velocities U c and U k , which delimit the turbulent regime are determined from the standard deviation of the absolute pressure, and were found to increase with increasing H s and not depend on axial positions. Radial profiles of the mean axial and transversal velocities have been determined with a PDA instrument. Two shapes of axial velocity profile (parabolic and concave) have been identified for the first distribution of particles (small particles). The shape is found to depend on the static bed height and the superficial gas velocity. Parabolic profiles were always found for the second distribution (large particles). The transversal velocities show that the particles move toward the riser center for small static bed heights H s in the turbulent regime. This movement change toward the wall with increasing H s, especially in the near wall region. More attention has been paid to the fluctuating character of the solid phase in analyzing the standard deviation of the mean axial and transversal particle velocities.

Research paper thumbnail of Kinetic characterization of the fuel stage of the chemical switching reforming proces through TGA-MS studies

Kinetic characterization of the fuel stage of the chemical switching reforming proces through TGA-MS studies

Research paper thumbnail of The effect of gas extraction through vertical membranes on the bubble hydrodynamics in a fluidized bed reactor

The effect of gas extraction through vertical membranes on the bubble hydrodynamics in a fluidized bed reactor

Research paper thumbnail of Characterization of Turbulent Regime Behavior in the Dilute Zone of a Circulating Fluidized Bed Riser

This study consists in characterizing the solid phase behavior in the dilute region of a circulat... more This study consists in characterizing the solid phase behavior in the dilute region of a circulating fluidized bed riser (CFB) for the turbulent regime (i.e. for superficial gas velocities U c <U g <U k). Two sizes of particles (109 µm and 175 µm), and different static bed heights H s (50 mm, 100 mm and 150 mm) for each distribution of particle, have been studied. Transition velocities U c and U k , which delimit the turbulent regime are determined from the standard deviation of the absolute pressure, and were found to increase with increasing H s and not depend on axial positions. Radial profiles of the mean axial and transversal velocities have been determined with a PDA instrument. Two shapes of axial velocity profile (parabolic and concave) have been identified for the first distribution of particles (small particles). The shape is found to depend on the static bed height and the superficial gas velocity. Parabolic profiles were always found for the second distribution (large particles). The transversal velocities show that the particles move toward the riser center for small static bed heights H s in the turbulent regime. This movement change toward the wall with increasing H s, especially in the near wall region. More attention has been paid to the fluctuating character of the solid phase in analyzing the standard deviation of the mean axial and transversal particle velocities.

Research paper thumbnail of Optimal particle parameters for CLC and CLR processes - predictions by intra-particle transport models and experimental validation

Validated models for predicting oxidation and reduction kinetics of multi-component porous partic... more Validated models for predicting oxidation and reduction kinetics of multi-component porous particles in chemical looping combustion (CLC) and chemical looping combustion (CLC) processes are of key importance to identify the rate limiting in these processes. Since particle properties (i.e., their composition, porosity, pore size, grain size, etc.) can be adjusted by modern synthesis techniques, there is an open question on the optimal set of these properties that would lead to the most economic process. In this study we present an overview of recent developments [1,2] in the field of continuum and shrinking-core-type intra-particle models. We then introduce a general open-source simulation environment, called ParScale, that can be used to simulate models relevant for CLC and CLR processes. Most important, ParScale features a generalized one-dimensional spherical discretization which enables the user to predict an arbitrary number of reactions within non-isothermal porous particles co...

Research paper thumbnail of Combined Syngas and Hydrogen Production using Gas Switching Technology

Industrial & Engineering Chemistry Research

This paper focuses on the experimental demonstration of a threestage GST (gas switching technolog... more This paper focuses on the experimental demonstration of a threestage GST (gas switching technology) process (fuel, steam/CO 2 , and air stages) for syngas production from methane in the fuel stage and H 2 /CO production in the steam/CO 2 stage using a lanthanum-based oxygen carrier (La 0.85 Sr 0.15 Fe 0.95 Al 0.05 O 3). Experiments were performed at temperatures between 750−950°C and pressures up to 5 bar. The results show that the oxygen carrier exhibits high selectivity to oxidizing methane to syngas at the fuel stage with improved process performance with increasing temperature although carbon deposition could not be avoided. Co-feeding CO 2 with CH 4 at the fuel stage reduced carbon deposition significantly, thus reducing the syngas H 2 /CO molar ratio from 3.75 to 1 (at CO 2 /CH 4 ratio of 1 at 950°C and 1 bar). The reduced carbon deposition has maximized the purity of the H 2 produced in the consecutive steam stage thus increasing the process attractiveness for the combined production of syngas and pure hydrogen. Interestingly, the cofeeding of CO 2 with CH 4 at the fuel stage showed a stable syngas production over 12 hours continuously and maintained the H 2 /CO ratio at almost unity, suggesting that the oxygen carrier was exposed to simultaneous partial oxidation of CH 4 with the lattice oxygen which was restored instantly by the incoming CO 2. Furthermore, the addition of steam to the fuel stage could tune up the H 2 /CO ratio beyond 3 without carbon deposition at H 2 O/ CH 4 ratio of 1 at 950°C and 1 bar; making the syngas from gas switching partial oxidation suitable for different downstream processes, for example, gas-to-liquid processes. The process was also demonstrated at higher pressures with over 70% fuel conversion achieved at 5 bar and 950°C.

Research paper thumbnail of Pressurized chemical looping methane reforming to syngas for efficient methanol production: experimental and process simulation study

Pressurized chemical looping methane reforming to syngas for efficient methanol production: experimental and process simulation study

Advances in Applied Energy

Research paper thumbnail of Study of the Cost Reductions Achievable from the Novel SARC CO2 Capture Concept Using a Validated Reactor Model

Industrial & Engineering Chemistry Research

New process concepts, such as the swing adsorption reactor cluster (SARC) CO 2 capture process, a... more New process concepts, such as the swing adsorption reactor cluster (SARC) CO 2 capture process, are often technoeconomically investigated using idealized modeling assumptions. This study quantifies the impact of this practice by updating a previous economic assessment with results from an improved reactor model validated against recently completed SARC lab-scale demonstration experiments. The experimental comparison showed that the assumption of chemical equilibrium was valid, that the previously employed heat transfer coefficient was conservatively low, and that the required reduction of axial mixing could be easily achieved using simple perforated plates in the reactor. However, the assumption of insignificant effects of the hydrostatic pressure gradient needed to be revised. In the economic assessment, the negative effect of the hydrostatic pressure gradient was almost canceled out by deploying the experimentally observed heat transfer coefficients, resulting in a small net increase in CO 2 avoidance costs of 2.8−4.8% relative to the unvalidated model. Further reductions in axial mixing via more perforated plates only brought minor benefits, but a shorter reactor enabled by the fast experimentally observed adsorption kinetics had a larger positive effect: halving the reactor height reduced CO 2 avoidance costs by 13.3%. A new heat integration scheme feeding vacuum pressure steam raised from several low-grade heat sources to the SARC desorption step resulted in similar gains. When all improvements were combined, the optimal CO 2 avoidance cost was 23.7% below the best result from prior works. The main uncertainty that needs to be overcome to realize the great economic potential of the SARC concept is long-term sorbent stability: mechanical stability must be improved substantially and long-term chemical stability under real flue gas conditions must be demonstrated.

Research paper thumbnail of Hydrogen production by water splitting using gas switching technology

Hydrogen production by water splitting using gas switching technology

Powder Technology

Research paper thumbnail of Demonstration of the Novel Swing Adsorption Reactor Cluster Concept in a Multistage Fluidized Bed with Heat-Transfer Surfaces for Postcombustion CO2 Capture

Demonstration of the Novel Swing Adsorption Reactor Cluster Concept in a Multistage Fluidized Bed with Heat-Transfer Surfaces for Postcombustion CO2 Capture

Industrial & Engineering Chemistry Research

Research paper thumbnail of Review on Reactor Configurations for Adsorption-Based CO2 Capture

Industrial & Engineering Chemistry Research

Adsorption-based CO 2 capture has enjoyed considerable research attention in recent years. Most o... more Adsorption-based CO 2 capture has enjoyed considerable research attention in recent years. Most of the research efforts focused on sorbent development to reduce the energy penalty. However, the use of suitable gas−solid contacting systems is key for extracting the full potential from the sorbent to minimize operating and capital costs and accelerate the commercial deployment of the technology. This paper reviews several reactor configurations that were proposed for adsorptionbased CO 2 capture. The fundamental behavior of adsorption in different gas−solid contactors (fixed, fluidized, moving, or rotating beds) and regeneration under different modes (pressure, temperature, or combined swings) is discussed, highlighting the strengths and limitations of different combinations of gas−solid contactor and regeneration mode. In addition, the estimated energy duties in published studies and current technology readiness level of the different reactor configurations are reported. Other aspects, such as the reactor footprint, the operation strategy, suitability to retrofits, and the ability to operate under flexible loads are also discussed. In terms of future work, the key research need is a standardized techno-economic benchmarking study to calculate CO 2 avoidance costs for different adsorption technologies under standardized assumptions. Qualitatively, each technology presents several strengths and weaknesses that make it impossible to identify a clear optimal solution. Such a standardized quantitative comparison is therefore needed to focus on future technology development efforts.

Research paper thumbnail of Review of pressurized chemical looping processes for power generation and chemical production with integrated CO2 capture

Review of pressurized chemical looping processes for power generation and chemical production with integrated CO2 capture

Fuel Processing Technology

Research paper thumbnail of Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

Chemical Engineering Journal

Research paper thumbnail of The effect of sorbent regeneration enthalpy on the performance of the novel Swing Adsorption Reactor Cluster (SARC) for post-combustion CO2 capture

The effect of sorbent regeneration enthalpy on the performance of the novel Swing Adsorption Reactor Cluster (SARC) for post-combustion CO2 capture

Chemical Engineering Journal

Research paper thumbnail of Mapping the operating performance of a novel internally circulating fluidized bed reactor applied to chemical looping combustion

Mapping the operating performance of a novel internally circulating fluidized bed reactor applied to chemical looping combustion

Fuel Processing Technology