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Changsui Zhao - One of the best experts on this subject based on the ideXlab platform.
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Calcium Based Sorbent doped with attapulgite for co2 capture
Applied Energy, 2013Co-Authors: Huichao Chen, Changsui ZhaoAbstract:Abstract Attempt to enhance CO 2 uptake of Calcium Based Sorbents by doping limestone with attapulgite was made and successfully achieved its effectiveness. The appropriate doping mode and optimal ratio were identified. The cyclic carbonation behavior was conducted under conditions of different carbonation temperature, calcination temperature, CO 2 partial pressure in carbonation and calcination atmosphere. Microstructure and compositions of Sorbents were analyzed to serve as a supplement to the studies. Results show that the optimal doping ratio of attapulgite to calcined limestone was 15 wt.% in the process of hydration. The doped Sorbent displayed much better CO 2 capture performance than the natural limestone by 128% increase after 20 cycles under the same condition (calcination at 950 °C in 100% CO 2 and carbonation at 700 °C in 15% CO 2 /85%N 2 ). Excellent microstructure of the modified Sorbent was created by doping attapulgite enabling higher CO 2 capture capacity. Ca 2 SiO 4 , Al 2 O 3 and Ca 3 Al 10 O 18 distributed in the Sorbent by XRD analysis enhanced its sintering-resistant leading to slow decrease in CO 2 capture capacity during multiple cycles.
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enhancement of attrition resistance and cyclic co2 capture of Calcium Based Sorbent pellets
Fuel Processing Technology, 2013Co-Authors: Huichao Chen, Changsui Zhao, Yanmei YangAbstract:Calcination/carbonation of Calcium-Based Sorbent is considered one of the most promising technologies to capture CO2. The attrition resistance and CO2 uptake of Ca-Based Sorbent were of great concern. Efforts were made to enhance the attrition resistance of Sorbents primarily by making Sorbent pellets with aluminate cements and maintain high CO2 capture capacity of Sorbents by adding pore forming agents. Batch experiments were conducted in a fluidized bed to investigate the effect of parameters on Sorbent attrition. CO2 capture performance of the pellets was also examined in a calcination/carbonation reactor system. The pore structure characteristics (BET, BJH) were measured as a supplement to the attrition and reaction studies. Results showed that the mechanical property of the pellets with 10 wt.% aluminate cement was greatly enhanced. While, CO2 capture capacity of the pellets made with 10 wt.% aluminate cement and 5–10 wt.% pores forming agent was greatly increased and displayed much slower decay during multiple cycles compared with the original limestone. This was attributed to the large number of mesopores caused by the use of chemical agents and the exposure of inner core of CaO Sorbents due to the attrition, which are in favor of CO2 capture. The pore structure showed that the BET surface area and BJH pore volume were expanded by adding pore forming agents, which benefits CO2 uptake of the Sorbents during the cycling.
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co2 capture efficiency and energy requirement analysis of power plant using modified Calcium Based Sorbent looping cycle
Energy, 2011Co-Authors: Changsui Zhao, Huichao Chen, Qiangqiang Ren, Lunbo DuanAbstract:Abstract This paper examines the average carbonation conversion, CO2 capture efficiency and energy requirement for post-combustion CO2 capture system during the modified Calcium-Based Sorbent looping cycle. The limestone modified with acetic acid solution, i.e. Calcium acetate is taken as an example of the modified Calcium-Based Sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural Sorbent under the same condition. The CO2 capture efficiency increases with the Sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh Sorbent is needed for the system when using the modified limestone at the same CO2 capture efficiency. Achieving 0.95 of CO2 capture efficiency without sulfation, 272 kJ/mol CO2 is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO2 for the modified Sorbent. The modified limestone possesses greater advantages in CO2 capture efficiency and energy consumption than the natural Sorbent. When the sulfation and carbonation of the Sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO2 from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.
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effect of rice husk ash addition on co2 capture behavior of Calcium Based Sorbent during Calcium looping cycle
Fuel Processing Technology, 2009Co-Authors: Changsui Zhao, Huichao Chen, Qiangqiang Ren, Lunbo Duan, Xiaoping ChenAbstract:Abstract Rice husk ash/CaO was proposed as a CO 2 Sorbent which was prepared by rice husk ash and CaO hydration together. The CO 2 capture behavior of rice husk ash/CaO Sorbent was investigated in a twin fixed bed reactor system, and its apparent morphology, pore structure characteristics and phase variation during cyclic carbonation/calcination reactions were examined by SEM-EDX, N 2 adsorption and XRD, respectively. The optimum preparation conditions for rice husk ash/CaO Sorbent are hydration temperature of 75 °C, hydration time of 8 h, and mole ratio of SiO 2 in rice husk ash to CaO of 1.0. The cyclic carbonation performances of rice husk ash/CaO at these preparation conditions were compared with those of hydrated CaO and original CaO. The temperature at 660 °C–710 °C is beneficial to CO 2 absorption of rice husk ash/CaO, and it exhibits higher carbonation conversions than hydrated CaO and original CaO during multiple cycles at the same reaction conditions. Rice husk ash/CaO possesses better anti-sintering behavior than the other Sorbents. Rice husk ash exhibits better effect on improving cyclic carbonation conversion of CaO than pure SiO 2 and diatomite. Rice husk ash/CaO maintains higher surface area and more abundant pores after calcination during the multiple cycles; however, the other Sorbents show a sharp decay at the same reaction conditions. Ca 2 SiO 4 found by XRD detection after calcination of rice husk ash/CaO is possibly a key factor in determining the cyclic CO 2 capture behavior of rice husk ash/CaO.
Huichao Chen - One of the best experts on this subject based on the ideXlab platform.
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Calcium Based Sorbent doped with attapulgite for co2 capture
Applied Energy, 2013Co-Authors: Huichao Chen, Changsui ZhaoAbstract:Abstract Attempt to enhance CO 2 uptake of Calcium Based Sorbents by doping limestone with attapulgite was made and successfully achieved its effectiveness. The appropriate doping mode and optimal ratio were identified. The cyclic carbonation behavior was conducted under conditions of different carbonation temperature, calcination temperature, CO 2 partial pressure in carbonation and calcination atmosphere. Microstructure and compositions of Sorbents were analyzed to serve as a supplement to the studies. Results show that the optimal doping ratio of attapulgite to calcined limestone was 15 wt.% in the process of hydration. The doped Sorbent displayed much better CO 2 capture performance than the natural limestone by 128% increase after 20 cycles under the same condition (calcination at 950 °C in 100% CO 2 and carbonation at 700 °C in 15% CO 2 /85%N 2 ). Excellent microstructure of the modified Sorbent was created by doping attapulgite enabling higher CO 2 capture capacity. Ca 2 SiO 4 , Al 2 O 3 and Ca 3 Al 10 O 18 distributed in the Sorbent by XRD analysis enhanced its sintering-resistant leading to slow decrease in CO 2 capture capacity during multiple cycles.
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enhancement of attrition resistance and cyclic co2 capture of Calcium Based Sorbent pellets
Fuel Processing Technology, 2013Co-Authors: Huichao Chen, Changsui Zhao, Yanmei YangAbstract:Calcination/carbonation of Calcium-Based Sorbent is considered one of the most promising technologies to capture CO2. The attrition resistance and CO2 uptake of Ca-Based Sorbent were of great concern. Efforts were made to enhance the attrition resistance of Sorbents primarily by making Sorbent pellets with aluminate cements and maintain high CO2 capture capacity of Sorbents by adding pore forming agents. Batch experiments were conducted in a fluidized bed to investigate the effect of parameters on Sorbent attrition. CO2 capture performance of the pellets was also examined in a calcination/carbonation reactor system. The pore structure characteristics (BET, BJH) were measured as a supplement to the attrition and reaction studies. Results showed that the mechanical property of the pellets with 10 wt.% aluminate cement was greatly enhanced. While, CO2 capture capacity of the pellets made with 10 wt.% aluminate cement and 5–10 wt.% pores forming agent was greatly increased and displayed much slower decay during multiple cycles compared with the original limestone. This was attributed to the large number of mesopores caused by the use of chemical agents and the exposure of inner core of CaO Sorbents due to the attrition, which are in favor of CO2 capture. The pore structure showed that the BET surface area and BJH pore volume were expanded by adding pore forming agents, which benefits CO2 uptake of the Sorbents during the cycling.
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co2 capture efficiency and energy requirement analysis of power plant using modified Calcium Based Sorbent looping cycle
Energy, 2011Co-Authors: Changsui Zhao, Huichao Chen, Qiangqiang Ren, Lunbo DuanAbstract:Abstract This paper examines the average carbonation conversion, CO2 capture efficiency and energy requirement for post-combustion CO2 capture system during the modified Calcium-Based Sorbent looping cycle. The limestone modified with acetic acid solution, i.e. Calcium acetate is taken as an example of the modified Calcium-Based Sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural Sorbent under the same condition. The CO2 capture efficiency increases with the Sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh Sorbent is needed for the system when using the modified limestone at the same CO2 capture efficiency. Achieving 0.95 of CO2 capture efficiency without sulfation, 272 kJ/mol CO2 is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO2 for the modified Sorbent. The modified limestone possesses greater advantages in CO2 capture efficiency and energy consumption than the natural Sorbent. When the sulfation and carbonation of the Sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO2 from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.
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effect of rice husk ash addition on co2 capture behavior of Calcium Based Sorbent during Calcium looping cycle
Fuel Processing Technology, 2009Co-Authors: Changsui Zhao, Huichao Chen, Qiangqiang Ren, Lunbo Duan, Xiaoping ChenAbstract:Abstract Rice husk ash/CaO was proposed as a CO 2 Sorbent which was prepared by rice husk ash and CaO hydration together. The CO 2 capture behavior of rice husk ash/CaO Sorbent was investigated in a twin fixed bed reactor system, and its apparent morphology, pore structure characteristics and phase variation during cyclic carbonation/calcination reactions were examined by SEM-EDX, N 2 adsorption and XRD, respectively. The optimum preparation conditions for rice husk ash/CaO Sorbent are hydration temperature of 75 °C, hydration time of 8 h, and mole ratio of SiO 2 in rice husk ash to CaO of 1.0. The cyclic carbonation performances of rice husk ash/CaO at these preparation conditions were compared with those of hydrated CaO and original CaO. The temperature at 660 °C–710 °C is beneficial to CO 2 absorption of rice husk ash/CaO, and it exhibits higher carbonation conversions than hydrated CaO and original CaO during multiple cycles at the same reaction conditions. Rice husk ash/CaO possesses better anti-sintering behavior than the other Sorbents. Rice husk ash exhibits better effect on improving cyclic carbonation conversion of CaO than pure SiO 2 and diatomite. Rice husk ash/CaO maintains higher surface area and more abundant pores after calcination during the multiple cycles; however, the other Sorbents show a sharp decay at the same reaction conditions. Ca 2 SiO 4 found by XRD detection after calcination of rice husk ash/CaO is possibly a key factor in determining the cyclic CO 2 capture behavior of rice husk ash/CaO.
Liangshih Fan - One of the best experts on this subject based on the ideXlab platform.
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chemical looping systems for fossil energy conversions
2010Co-Authors: Liangshih FanAbstract:Preface. 1 Introduction. 1.1 Background. 1.1.1 Renewable Energy. 1.1.2 Fossil Energy Outlook. 1.2 Coal Combustion. 1.2.1 Energy Conversion Efficiency Improvement. 1.2.2 Flue Gas Pollutant Control Methods. 1.3 CO2 Capture. 1.4 CO2 Sequestration. 1.5 Coal Gasification. 1.6 Chemical Looping Concepts. 1.7 Chemical Looping Processes. 1.8 Overview of This Book. References. 2 Chemical Looping Particles. 2.1 Introduction. 2.2 Type I Chemical Looping System. 2.2.1 General Particle Characteristics. 2.2.2 Thermodynamics and Phase Equilibrium of Metals and Metal Oxides. 2.2.3 Particle Regeneration with Steam. 2.2.4 Reaction with Oxygen and Heat of Reaction. 2.2.5 Particle Design Considering Heat of Reaction. 2.2.6 Particle Preparation and Recyclability. 2.2.7 Particle Formulation and Effect of Support. 2.2.8 Effect of Particle Size and Mechanical Strength. 2.2.9 Carbon and Sulfur Formation Resistance. 2.2.10 Particle Reaction Mechanism. 2.2.11 Effect of Reactor Design and Gas-Solid Contact Modes.7 2.2.12 Selection of Primary Metal for Chemical Looping Combustion of Coal. 2.3 Type II Chemical Looping System. 2.3.1 Types of Metal Oxide. 2.3.2 Thermodynamics and Phase Equilibrium of Metal Oxide and Metal Carbonate. 2.3.3 Reaction Characteristics of Ca-Based Sorbents for CO2 Capture. 2.3.4 Synthesis of the High-Reactivity PCC-CaO Sorbent. 2.3.5 Reactivity of Calcium Sorbents. 2.3.6 Recyclability of Calcium Oxides. 2.4 Concluding Remarks. References. 3 Chemical Looping Combustion. 3.1 Introduction. 3.2 CO2 Capture Strategies for Fossil Fuel Combustion Power Plants. 3.2.1 Pulverized Coal Combustion Power Plants. 3.2.2 CO2 Capture Strategies. 3.3 Chemical Looping Combustion. 3.3.1 Particle Reactive Properties and Their Relationship with CLC Operation. 3.3.2 Key Design and Operational Parameters for a CFB-Based CLC System. 3.3.3 CLC Reactor System Design. 3.3.4 Gaseous Fuel CLC Systems and Operational Results. 3.3.5 Solid Fuel CLC Systems and Operational Results. 3.4 Concluding Remarks. References. 4 Chemical Looping Gasification Using Gaseous Fuels. 4.1 Introduction. 4.2 Traditional Coal Gasification Processes. 4.2.1 Electricity Production-Integrated Gasification Combined Cycle (IGCC). 4.2.2 H2 Production. 4.2.3 Liquid Fuel Production. 4.3 Iron-Based Chemical Looping Processes Using Gaseous Fuels. 4.3.1 Lane Process and Messerschmitt Process. 4.3.2 U.S. Bureau of Mines Pressurized Fluidized Bed Steam-Iron Process. 4.3.3 Institute of Gas Technology Process. 4.3.4 Syngas Chemical Looping (SCL) Process. 4.4 Design, Analysis and Optimization of the Syngas Chemical Looping (SCL) Process. 4.4.1 Thermodynamic Analyses of SCL Reactor Behavior. 4.4.2 ASPEN PLUS Simulation of SCL Reactor Systems. 4.4.3 Syngas Chemical Looping (SCL) Process Testing. 4.5 Process Simulation of the Traditional Gasification Process and the Syngas Chemical Looping Process. 4.5.1 Common Assumptions and Model Setup. 4.5.2 Description of Various Systems. 4.5.3 ASPEN PLUS Simulation, Results, and Analyses. 4.6 Example of SCL Applications-A Coal-to-Liquid Confi guration. 4.6.1 Process Overview. 4.6.2 Mass/Energy Balance and Process Evaluation. 4.7 Calcium Looping Process Using Gaseous Fuels. 4.7.1 Description of the Processes. 4.7.2 Reaction Characteristics of the Processes. 4.7.3 Analyses of the Processes. 4.7.4 Enhanced Coal-to-Liquid (CTL) Process with Sulfur and CO2 Capture. 4.8 Concluding Remarks. References. 5 Chemical Looping Gasification Using Solid Fuels. 5.1 Introduction. 5.2 Chemical Looping Gasification Processes Using Calcium-Based Sorbent. 5.2.1 CO2 Acceptor Process. 5.2.2 HyPr-Ring Process. 5.2.3 Zero Emission Coal Alliance Process. 5.2.4 ALSTOM Hybrid Combustion-Gasification Process. 5.2.5 Fuel-Flexible Advanced Gasification-Combustion Process. 5.2.6 General Comments. 5.3 Coal-Direct Chemical Looping (CDCL) Processes Using Iron-Based Oxygen Carriers. 5.3.1 Coal-Direct Chemical Looping Process-Configuration I. 5.3.2 Coal-Direct Chemical Looping Process-Configuration II. 5.3.3 Comments on the Iron-Based Coal-Direct Chemical Looping Process. 5.4 Challenges to the Coal-Direct Chemical Looping Processes and Strategy for Improvements. 5.4.1 Oxygen-Carrier Particle Reactivity and Char Reaction Enhancement. 5.4.2 Configurations and Conversions of the Reducer. 5.4.3 Performance of the Oxidizer and the Combustor. 5.4.4 Fate of Pollutants and Ash. 5.4.5 Energy Management, Heat Integration, and General Comments. 5.5 Process Simulation on the Coal-Direct Chemical Looping Process. 5.5.1 ASPEN Model Setup. 5.5.2 Simulation Results. 5.6 Concluding Remarks. References. 6 Novel Applications of Chemical Looping Technologies. 6.1 Introduction. 6.2 Hydrogen Storage and Onboard Hydrogen Production. 6.2.1 Compressed Hydrogen Gas and Liquefi ed Hydrogen. 6.2.2 Metal Hydrides. 6.2.3 Bridged Metal-Organic Frameworks. 6.2.4 Carbon Nanotubes and Graphite Nanofibers. 6.2.5 Onboard Hydrogen Production via Iron Based Materials. 6.3 Carbonation-Calcination Reaction (CCR) Process for Carbon Dioxide Capture. 6.4 Chemical Looping Gasification Integrated with Fuel Cells. 6.4.1 Chemical Looping Gasification Integrated with Solid-Oxide Fuel Cells. 6.4.2 Direct Solid Fuel Cells. 6.5 Enhanced Steam Methane Reforming. 6.6 Tar Sand Digestion via Steam Generation. 6.7 Liquid Fuel Production from Chemical Looping Gasification. 6.8 Chemical Looping with Oxygen Uncoupling (CLOU). 6.9 Concluding Remarks. References. Subject Index. Author Index.
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subpilot demonstration of the carbonation calcination reaction ccr process high temperature co2 and sulfur capture from coal fired power plants
Industrial & Engineering Chemistry Research, 2010Co-Authors: William S Y Wang, Shwetha Ramkumar, Danny S Wong, Mahesh V Iyer, Bartev B Sakadjian, Robert Statnick, Liangshih FanAbstract:Increasing concerns over growing CO2 levels in the atmosphere have led to a worldwide demand for efficient, cost-effective, and clean carbon capture technologies. One of these technologies is the Carbonation−Calcination Reaction (CCR) process, which utilizes a Calcium-Based Sorbent in a high-temperature reaction (carbonation) to capture the CO2 from the flue gas stream and releases a pure stream of CO2 in the subsequent calcination reaction that can be sequestered. A 120 KWth subpilot-scale combustion plant utilizing coal at 20 pph along with natural gas has been established at The Ohio State University to test the CCR process. Experimental studies on CO2 capture using Calcium-Based Sorbents have been performed at this facility. Greater than 99% CO2 and SO2 capture has been achieved at the subpilot-scale facility on a once-through basis at a Ca:C mole ratio of 1.6. In addition, the Sorbent reactivity is maintained over multiple cycles by the incorporation of a Sorbent reactivation hydration step in the ca...
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dispersion and ultra fast reaction of Calcium Based Sorbent powders for so2 and air toxics removal in coal combustion
Chemical Engineering Science, 1999Co-Authors: Liangshih Fan, Peijun Jiang, Rajeev Agnihotri, Suhas K Mahuli, Jianping Zhang, S Chauk, Abhijit GhoshdastidarAbstract:Abstract This paper addresses the various fundamental issues related to the reaction and dispersion of Sorbents, and the impact of developments in the Sorbent science and technology on the design and operation of CFB combustors. The central role of Sorbents in fluidized-bed combustors, the current state of the art in Sorbents for SO2 capture, and their influence on NOx and other pollutant removal are highlighted. The existing CFB designs and the current Sorbent technology are capable of achieving up to 90% sulfur capture. Sulfur removals of greater than 93%, expected to be mandated in the near future, require considerable increase in Ca/S ratios and lead to increased NOx, reduced combustion efficiency, and other operating problems. The current CFB combustor design and operating parameters such as temperature, Sorbent particle size etc., can be optimized for best possible sulfur and NOx control using limestone Sorbent. There is a need, and a definite scope for improving the Sorbents to augment sulfur capture without increasing Sorbent consumption. This paper also elaborates the development of high reactivity limestone Sorbents and their exceptionally high sulfur capture rate and capacity. The kinetics of sulfur capture dictates smaller particle sizes for higher rate of reaction. Thus, the analyses of Sorbents of size less than 50 μm with consideration of their application towards sulfur capture during coal combustion is attempted. A viable option for operating CFBs with smaller Sorbent particles at higher temperatures is examined. Current challenges such as improved Sorbents development for advanced combustion/gasification systems, capture of trace air toxics and other metallic species, and improved particle separation systems for CFB operation, are also discussed.
M R Rahimpour - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of improved Calcium Based co2 Sorbent and co3o4 sio2 oxygen carrier for clean production of hydrogen in sorption enhanced chemical looping reforming
International Journal of Hydrogen Energy, 2019Co-Authors: A Hafizi, M R Rahimpour, M HeraviAbstract:Abstract In this study, highly pure hydrogen is produced in sorption enhanced chemical looping steam methane reforming (SE-CLSMR) using cobalt-Based oxygen carrier (OC) and cerium promoted CaO-Based Sorbent. In addition, the CO2 removal from a gas stream at high temperatures is investigated via Calcium looping process prior to SE-CLSMR process. The prepared samples are characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and energy dispersive X-ray spectroscopy (EDX) techniques. The effect of Ca/Ce molar ratio (100/0.00–0.91/0.09), sorption temperature (550–650 °C) and Sorbent lifetime are studied to find the optimal Sorbent. The characterization results show the uniform and orderly CeO2 dispersed Sorbent nanoparticles that notably improved the Sorbent morphology compared with blank CaO. The sorption results revealed the negative effect of temperature on CO2 uptake of all the samples. In addition, the CO2 sorption evaluations indicate that the molar ratio of cerium to Calcium plays a significant role in the stability of Sorbent and improved the CO2 sorption capacity significantly. The high CO2 removal efficiency in the cerium modified Sorbents could be due to decrease in diffusion resistance of CO2 through the Sorbent structure during the carbonation reaction. Furthermore, results show that the addition of cerium to the Sorbent structure, effectively improves the thermal resistance of synthesis Sorbents. The SE-CLSMR results showed that the H2 purity could be increased up to about 95% considering Co3O4/SiO2 oxygen carrier and cerium promoted Calcium-Based Sorbent at relatively low temperature of 550 °C, which is comparable with 84% in CLR process.
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high purity hydrogen production via sorption enhanced chemical looping reforming application of 22fe2o3 mgal2o4 and 22fe2o3 al2o3 as oxygen carriers and cerium promoted cao as co2 Sorbent
Applied Energy, 2016Co-Authors: A Hafizi, M R Rahimpour, Shadi HassanajiliAbstract:Abstract High purity hydrogen can be produced using sorption enhanced chemical looping reforming (SE–CLR) in which an oxygen carrier and an in situ CO 2 Sorbent are involved. In this study, the effectiveness of alumina modification with Mg as the support of Fe 2 O 3 Based oxygen carriers is investigated in CLR and SE–CLR processes for clean hydrogen production. The 22Fe 2 O 3 /Al 2 O 3 and 22Fe 2 O 3 /MgAl 2 O 4 oxygen carriers are synthesized with impregnation and sequential impregnation methods, respectively. Prior to SE–CLR process, the performance of three different Calcium Based Sorbents including industrial CaO, synthesized CaO and cerium promoted CaO are investigated for CO 2 sorption in Calcium loop. The characterization of the oxygen carriers and Sorbent samples is performed by XRD, BET, FESEM and TEM. It is found that the addition of cerium to the Calcium-Based Sorbent effectively improves its structural properties and CO 2 sorption performance. The obtained results reveal that the Sorbent surface area is a significant parameter affecting its CO 2 removal efficiency at high temperatures. In addition, the presence of Mg in oxygen carrier structure successfully prevents the formation of Fe–Al spinel by MgAl 2 O 4 formation. An excessive H 2 /CO molar ratio of 16.7 is also achieved using Fe 2 O 3 /MgAl 2 O 4 oxygen carrier and synthesized Ce/Ca = 0.2 Sorbent at 600 °C in SE–CLR process.
A Hafizi - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of improved Calcium Based co2 Sorbent and co3o4 sio2 oxygen carrier for clean production of hydrogen in sorption enhanced chemical looping reforming
International Journal of Hydrogen Energy, 2019Co-Authors: A Hafizi, M R Rahimpour, M HeraviAbstract:Abstract In this study, highly pure hydrogen is produced in sorption enhanced chemical looping steam methane reforming (SE-CLSMR) using cobalt-Based oxygen carrier (OC) and cerium promoted CaO-Based Sorbent. In addition, the CO2 removal from a gas stream at high temperatures is investigated via Calcium looping process prior to SE-CLSMR process. The prepared samples are characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and energy dispersive X-ray spectroscopy (EDX) techniques. The effect of Ca/Ce molar ratio (100/0.00–0.91/0.09), sorption temperature (550–650 °C) and Sorbent lifetime are studied to find the optimal Sorbent. The characterization results show the uniform and orderly CeO2 dispersed Sorbent nanoparticles that notably improved the Sorbent morphology compared with blank CaO. The sorption results revealed the negative effect of temperature on CO2 uptake of all the samples. In addition, the CO2 sorption evaluations indicate that the molar ratio of cerium to Calcium plays a significant role in the stability of Sorbent and improved the CO2 sorption capacity significantly. The high CO2 removal efficiency in the cerium modified Sorbents could be due to decrease in diffusion resistance of CO2 through the Sorbent structure during the carbonation reaction. Furthermore, results show that the addition of cerium to the Sorbent structure, effectively improves the thermal resistance of synthesis Sorbents. The SE-CLSMR results showed that the H2 purity could be increased up to about 95% considering Co3O4/SiO2 oxygen carrier and cerium promoted Calcium-Based Sorbent at relatively low temperature of 550 °C, which is comparable with 84% in CLR process.
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high purity hydrogen production via sorption enhanced chemical looping reforming application of 22fe2o3 mgal2o4 and 22fe2o3 al2o3 as oxygen carriers and cerium promoted cao as co2 Sorbent
Applied Energy, 2016Co-Authors: A Hafizi, M R Rahimpour, Shadi HassanajiliAbstract:Abstract High purity hydrogen can be produced using sorption enhanced chemical looping reforming (SE–CLR) in which an oxygen carrier and an in situ CO 2 Sorbent are involved. In this study, the effectiveness of alumina modification with Mg as the support of Fe 2 O 3 Based oxygen carriers is investigated in CLR and SE–CLR processes for clean hydrogen production. The 22Fe 2 O 3 /Al 2 O 3 and 22Fe 2 O 3 /MgAl 2 O 4 oxygen carriers are synthesized with impregnation and sequential impregnation methods, respectively. Prior to SE–CLR process, the performance of three different Calcium Based Sorbents including industrial CaO, synthesized CaO and cerium promoted CaO are investigated for CO 2 sorption in Calcium loop. The characterization of the oxygen carriers and Sorbent samples is performed by XRD, BET, FESEM and TEM. It is found that the addition of cerium to the Calcium-Based Sorbent effectively improves its structural properties and CO 2 sorption performance. The obtained results reveal that the Sorbent surface area is a significant parameter affecting its CO 2 removal efficiency at high temperatures. In addition, the presence of Mg in oxygen carrier structure successfully prevents the formation of Fe–Al spinel by MgAl 2 O 4 formation. An excessive H 2 /CO molar ratio of 16.7 is also achieved using Fe 2 O 3 /MgAl 2 O 4 oxygen carrier and synthesized Ce/Ca = 0.2 Sorbent at 600 °C in SE–CLR process.