The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform
Muhammad Asif - One of the best experts on this subject based on the ideXlab platform.
-
Process simulation of ammonia-based CO2 capture and regeneration in packed column
International Journal of Global Warming, 2015Co-Authors: Muhammad AsifAbstract:Post-combustion CO2 capture using aqueous ammonia offers advantages over the conventional amines solvent, including lack of corrosion, an enhanced CO2 loading capacity and low energy input requirement for solvent regeneration. In this paper, an aqueous ammonia-based CO2 absorption-desorption process integrated with washing column is modelled and simulated in Aspen Plus®. The predicted results agreed with published experimental results. The effect of performance parameters such as the ammonia concentration in lean solution, CO2 fraction in the flue Gas, inlet Feed Gas Temperature, stripper operating Temperature and pressure, lean solution Temperature and flow rates of the flue Gas, were investigated. The Gas Temperature showed trivial effect on CO2 absorption efficiency; therefore the absorber column can be fed with hot flue Gases, eliminating the need for cooling. The results show that the washing columns coupled at top of the absorber and stripper columns enabled the system to maintain ammonia slip within permissible level.
-
experimental study on co2 capture by chilled ammonia process
Chemical Engineering Journal, 2015Co-Authors: Muhammad AsifAbstract:Abstract Aqueous, ammonia-based CO2 capture is attractive because of its low cost, low heat energy requirement, high CO2 absorption capacity, low degradation rate, and ability to capture multiple pollutants simultaneously. The most serious problem of a carbon dioxide capture process that uses aqueous ammonia is a phenomenon involving ammonia vaporization known as ammonia slip. The chilled ammonia process (CAP) is an improved ammonia-based CO2 capture technology. Recent attention has been given to the process patented by Gal (2008), which involves a system operated at a low Temperature to minimize the ammonia loss due to evaporation. This study focuses on the laboratory-scale experiment for analysis of the chilled ammonia process. The CO2 absorption ratio and amount of ammonia slip are measured at various operating conditions. The concentration of ammonia is fixed at 7 wt.%, while the Temperature of Feed Gas and liquid solution was varied from 2 °C to 20 °C. The effect of Feed Gas Temperature and absorbent Temperature on ammonia slip and CO2 absorption efficiency is examined experimentally. The results indicate that ammonia slip and CO2 absorption efficiency are changed significantly by varying the Temperature of liquid solution, while Feed Gas Temperature showed a trivial impact on the CO2 absorption ratio and ammonia slip. Moreover, when the absorber was operated at lean solution Temperature and Feed Gas Temperature of 7 °C and 10 °C, respectively, the CO2 absorption efficiency was above 85% and ammonia slip was minimized.
Mohamed A Habib - One of the best experts on this subject based on the ideXlab platform.
-
Simulation of CO2 adsorption-separation from an N2/CO2 Gas mixture in a fixed Mg-MOF-74 column
International Journal of Global Warming, 2017Co-Authors: Rached Ben-mansour, O. E. Bamidele, Mohamed A Habib, Abdul Malik Puthan PeedikakkalAbstract:A computational study of adsorption-separation of CO2 from an N2/CO2 Gas mixture is presented in this paper. A detailed one-dimensional, transient mathematical model has been formulated to include the heat and mass transfer, the pressure drop and multi-component mass diffusion. The model has been implemented on a MATLAB program using second order discretisation. Validation of the model was performed using a complete experimental data set for carbon dioxide separation using activated carbon. Simulation of the adsorption breakthrough experiment on fixed bed has been carried out to evaluate the capacity of Mg-MOF-74 for CO2 capture with varying Feed Gas Temperature of 301 K, 323 K, 373 K and 423 K. The results show the superiority of MOF adsorbent in comparison to activated carbon. The simulated breakthrough time for CO2 on Mg-MOF-74 with Feed Temperature and pressure of 301 K and 1.02 bar respectively is about 500 min as compared to 50 min for activated carbon. The amount of CO2 adsorbed on Mg-MOF-74 under this condition is 6.43 mole per kilogram of adsorbent. The maximum Temperature exhibited in the system is at the bed exit with a value of about 356 K after about 500 min of simulation.
-
Evaluation of Mg‐MOF‐74 for post‐combustion carbon dioxide capture through pressure swing adsorption
International Journal of Energy Research, 2015Co-Authors: Rached Ben-mansour, O. E. Bamidele, Mohamed A HabibAbstract:Summary This paper presents a computational study of an energy-efficient technique for post-combustion CO2 capture using novel material, namely, Mg-MOF-74, using pressure swing adsorption (PSA) processes. A detailed one-dimensional, transient mathematical model has been formulated to include the heat and mass transfer, the pressure drop and multicomponent mass diffusion. The PSA model has been further extended by incorporating a heat regenerating process to enhance CO2 sequestration. The heat dissipated during adsorption is stored in packed sand bed and released during desorption step for heating purpose. The model has been implemented on a MATLAB program using second-order discretization. Validation of the model was performed using a complete experimental data set for CO2 sequestration using zeolite 13X. Simulation of the PSA experiment on fixed bed has been carried out to evaluate the capacity of Mg-MOF-74 for CO2 capture with varying Feed Gas Temperature of 28 and 100 °C, varying pressurization and purge times and heat regeneration. It was discovered that the PSA process with heat regeneration system might be advantageous because it achieves equivalent amount of CO2 sequestration in fewer PSA cycles compared with PSA without heat regeneration system. Based on the simulated conditions, CO2 recovery with Mg-MOF-74 gives high percentage purity (above 98%) for the captured CO2. Copyright © 2015 John Wiley & Sons, Ltd.
Ching Tsung Yu - One of the best experts on this subject based on the ideXlab platform.
-
Reaction phenomena of high-Temperature water Gas shift reaction in a membrane reactor
Fuel, 2017Co-Authors: Wei-hsin Chen, Ching Wei Tsai, Rei Yu Chein, Ching Tsung YuAbstract:Abstract The membrane reactor is a promising device to produce pure hydrogen and enrich CO 2 from synGas. To figure out the detailed reaction phenomena of high-Temperature water Gas shift reaction (WGSR) in a Pd-based membrane reactor, a computational fluid dynamics (CFD) model is developed to simulate the chemical reaction where the Feed Gas Temperature and steam-to-CO molar ratio (S/C ratio) are in the ranges of 400–700 °C and 1–3, respectively. The predictions suggest that the WGSR proceeds from kinetically controlled reaction to thermodynamically governed one when the Feed Gas Temperature increases. The CO conversion at high Temperatures can be improved up to 83% when the membrane is in the reactor compared to that without the membrane. This is mainly attributed to the intensification of the membrane’s permeance with increasing Temperature, even though high Temperatures disadvantage CO conversion. The analysis also reveals that the breakthrough in the thermodynamic limit of CO conversion can be achieved in the membrane reactor when the Feed Gas Temperature is higher than 500 °C. The CO conversion in the membrane reactor can be higher than the thermodynamic equilibrium up to 61%.
Hamidreza Bakhtiary-davijany - One of the best experts on this subject based on the ideXlab platform.
-
Performance assessment of a packed bed microstructured reactor - heat exchanger for methanol synthesis from synGas
2020Co-Authors: Hamidreza Bakhtiary-davijanyAbstract:About 25% of the world’s proven natural Gas reserves are located offshore with no present economic feasibility to be produced, shipped and sold. Utilization of these resources calls for developing new technologies, which enable conversion of “remote natural Gas” to transportable fuels and chemicals at lower production capacities. On this context, investigation of compact methanol synthesis from synthesis Gas over Cu based catalysts in a multi-slit Integrated Micro Packed Bed Reactor-Heat Exchanger (IMPBRHE) has been the purpose of the present work through experimental and modelling approaches. A well equipped experimental setup was built and successfully operated. The main characteristics of the IMPBRHE for methanol synthesis over three catalysts; a commercial Cu/ZnO/support and two home-made Cu/ZnO/Al2O3catalysts were investigated. These include productivity, thermal behaviour, mass transfer properties and fluid flow. A wide range of industrial operating conditions were applied; 50 and 80 bar, 488–543 K and contact time of 50-500 ms g/ml. The results show near equilibrium CO conversion per pass is achievable at contact time of ~300 ms g/ml for the commercial catalyst and ~470 ms g/ml for the home made catalysts at 80 bar and 528 K. However, catalyst deactivation observed in experiments remains to be explained. Superior thermal behaviour of the IMPBRHE was investigated through Temperature measurements inside the middle reaction slit and at outer reactor skin. The results indicate a gradient of 1-2 K along the slit axis regardless of the rate of heat generation by the methanol synthesis at different conditions, i.e. high or low productivity when using a CO rich synGas. Moreover, the controlling factor of the slit Temperatures was found to be the Temperature of the cooling medium (heat transfer oil). Varying the Feed Gas Temperature had no significant effect on the CO conversion. It was shown that the reduction procedure could be replaced by applying the synGas directly, achieving similar activity and under isothermal conditions in the IMPBRHE and hence shortening of the reaction pre-treatment. Results also revealed minor sintering effects caused by exothermic methanol synthesis over a long time on stream. The possibility of film diffusion limitations was experimentally investigated. Variation of the total pressure and change of inert Gas was applied at Reynolds numbers ~1 to alter the diffusivities of reactants in the Gas mixture by dilution, while keeping reactant flow and partial pressure constant. It was shown that IMPBRHE operates in a regime with negligible external diffusion limitations. To evaluate possible internal mass transfer effects, experiments were performed with three different particle sizes and the results revealed the negligible pore diffusion limitation effects on the performance of the IMPBRHE under the relevant conditions applied. Results showed that the reaction media in the slits is isobaric (up to 8 mbar pressure drop over the IMPBRHE). According to the simulation results, the packed slit with the pillar structures delivers a velocity profile which is almost uniform over the distance between two pillars. The reproducibility of conversion and selectivity levels achieved upon applying different samples of the same catalyst batch, indicated that flow maldistribution between the slits is not significantly affecting the performance of the IMPBRHE. Through establishment of a systematic comparison strategy, the performance of the IMPBRHE was experimentally evaluated against a laboratory scale Fixed-Bed Reactor (FBR) with three dilution ratios. The IMPBRHE outperformed the undiluted FBR and gave CO conversions comparable to the diluted FBRs. The main difference seems to be the superior heat exchange properties of the IMPBRHE which can improve reactor performance for the exothermic methanol synthesis as compared with non-isothermal undiluted FBR. The results revealed the advantages of the IMPBRHE for robust scale up, not applicable for conventional lab-scale fixed-bed reactors due to different scaleup concept. Experiments were carried out using two IMPBRHEs in series to investigate the effect of inter-stage condensation. Some 15 increase in carbon conversions was achieved when methanol and water were condensed, relative to the experiments done without inter-stage condensation. A 2D-pseudo homogeneous mathematical model for a single slit packed bed microstructured reactor in the synthesis of methanol was developed in a 3D geometry using COMSOL Multiphysics software. The model is capable of predicting superior thermal behaviour and mass transfer properties as well as CO conversions in the IMPBRHE, all in a good agreement with the experimental data obtained. The verification of simulation results by experimental data shows promising features of the microstructured reactor for the compact methanol synthesis, as well as applicability of the developed model for further design and performance optimization of the reactor.
-
Modelling and simulation of a single slit micro packed bed reactor for methanol synthesis
Catalysis Today, 2020Co-Authors: Hamidreza Bakhtiary-davijany, Fatemeh Hayer, Xuyen Kim Phan, Rune Myrstad, Hilde J. Venvik, Peter Pfeifer, Anders HolmenAbstract:Abstract A mathematical model for a single slit packed microstructured reactor-heat exchanger in the synthesis of methanol from synGas was developed. The model constitutes a simplified 3D-pseudo homogeneous approach for a reaction slit with integrated pillar geometry. Literature kinetic rate expressions for methanol synthesis over commercial Cu/ZnO/support type catalysts were applied at 80 bar total pressure, Temperature range of 473-558 K, and synGas composition of H2/CO/CO2/N2:65/25/5/5 mol%. The model is found capable of predicting experimental CO conversion data with acceptable accuracy. Superior thermal stability of the microchannel upon variation of different parameters such as contact time, Feed Gas Temperature and reaction Temperature were shown. The simulation results also reveal that the microchannel reactor can operate free of performance loss due to concentrations field that may arise from overlaid Temperature fields. Simulations have also been used to calculate the rapid Temperature transients at the inlet. The agreement between simulation results and experimental data signifies the applicability of the developed model for further design and performance optimization of microstructured reactors for methanol synthesis and other exothermic processes.
O. E. Bamidele - One of the best experts on this subject based on the ideXlab platform.
-
Simulation of CO2 adsorption-separation from an N2/CO2 Gas mixture in a fixed Mg-MOF-74 column
International Journal of Global Warming, 2017Co-Authors: Rached Ben-mansour, O. E. Bamidele, Mohamed A Habib, Abdul Malik Puthan PeedikakkalAbstract:A computational study of adsorption-separation of CO2 from an N2/CO2 Gas mixture is presented in this paper. A detailed one-dimensional, transient mathematical model has been formulated to include the heat and mass transfer, the pressure drop and multi-component mass diffusion. The model has been implemented on a MATLAB program using second order discretisation. Validation of the model was performed using a complete experimental data set for carbon dioxide separation using activated carbon. Simulation of the adsorption breakthrough experiment on fixed bed has been carried out to evaluate the capacity of Mg-MOF-74 for CO2 capture with varying Feed Gas Temperature of 301 K, 323 K, 373 K and 423 K. The results show the superiority of MOF adsorbent in comparison to activated carbon. The simulated breakthrough time for CO2 on Mg-MOF-74 with Feed Temperature and pressure of 301 K and 1.02 bar respectively is about 500 min as compared to 50 min for activated carbon. The amount of CO2 adsorbed on Mg-MOF-74 under this condition is 6.43 mole per kilogram of adsorbent. The maximum Temperature exhibited in the system is at the bed exit with a value of about 356 K after about 500 min of simulation.
-
Evaluation of Mg‐MOF‐74 for post‐combustion carbon dioxide capture through pressure swing adsorption
International Journal of Energy Research, 2015Co-Authors: Rached Ben-mansour, O. E. Bamidele, Mohamed A HabibAbstract:Summary This paper presents a computational study of an energy-efficient technique for post-combustion CO2 capture using novel material, namely, Mg-MOF-74, using pressure swing adsorption (PSA) processes. A detailed one-dimensional, transient mathematical model has been formulated to include the heat and mass transfer, the pressure drop and multicomponent mass diffusion. The PSA model has been further extended by incorporating a heat regenerating process to enhance CO2 sequestration. The heat dissipated during adsorption is stored in packed sand bed and released during desorption step for heating purpose. The model has been implemented on a MATLAB program using second-order discretization. Validation of the model was performed using a complete experimental data set for CO2 sequestration using zeolite 13X. Simulation of the PSA experiment on fixed bed has been carried out to evaluate the capacity of Mg-MOF-74 for CO2 capture with varying Feed Gas Temperature of 28 and 100 °C, varying pressurization and purge times and heat regeneration. It was discovered that the PSA process with heat regeneration system might be advantageous because it achieves equivalent amount of CO2 sequestration in fewer PSA cycles compared with PSA without heat regeneration system. Based on the simulated conditions, CO2 recovery with Mg-MOF-74 gives high percentage purity (above 98%) for the captured CO2. Copyright © 2015 John Wiley & Sons, Ltd.