scholarly journals Computational Fluid Dynamics Modeling of the Fuel Reactor in NETL's 50 kWth Chemical Looping Facility

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ronald W. Breault ◽  
Justin Weber ◽  
Doug Straub ◽  
Sam Bayham
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Fixed Bed ◽  
Nucleation And Growth ◽  
Chemical Looping ◽  
Gravimetric Analysis ◽  
Oxygen Carriers ◽  
Dynamics Modeling ◽  
Fuel Reactor

The National Energy Technology Laboratory (NETL) has explored chemical looping in its 50 kWth facility using a number of oxygen carriers. In this work, the results for methane conversion in the fuel reactor with a hematite iron ore as the oxygen carrier are analyzed. The experimental results are compared to predictions using CPFD's barracuda computational fluid dynamics (CFD) code with kinetics derived from the analysis of fixed bed data. It has been found through analytical techniques from thermal gravimetric analysis data as well as the same fixed bed data that the kinetics for the methane–hematite reaction follows a nucleation and growth or Johnson–Mehl–Avrami (JMA) reaction mechanism. barracuda does not accept nucleation and growth kinetics; however, there is enough sufficient variability of the solids dependence within the software such that the nucleation and growth behavior can be mimicked. This paper presents the method to develop the pseudo-JMA kinetics for barracuda extracted from the fixed bed data and then applies these values to the fuel reactor data to compare the computational results to experimental data obtained from 50 kWth unit for validation. Finally, a fuel reactor design for near complete conversion is proposed.

Computational Fluid Dynamics Modeling of Chemical Looping Combustion Process with Calcium Sulphate Oxygen Carrier

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Baosheng Jin ◽  
Rui Xiao ◽  
Zhongyi Deng ◽  
Qilei Song
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Combustion Products ◽  
Calcium Sulphate ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Dynamics Modeling ◽  
Fuel Reactor

To concentrate CO2 in combustion processes by efficient and energy-saving ways is a first and very important step for its sequestration. Chemical looping combustion (CLC) could easily achieve this goal. A chemical-looping combustion system consists of a fuel reactor and an air reactor. Two reactors in the form of interconnected fluidized beds are used in the process: (1) a fuel reactor where the oxygen carrier is reduced by reaction with the fuel, and (2) an air reactor where the reduced oxygen carrier from the fuel reactor is oxidized with air. The outlet gas from the fuel reactor consists of CO2 and H2O, while the outlet gas stream from the air reactor contains only N2 and some unused O2. The water in combustion products can be easily removed by condensation and pure carbon dioxide is obtained without any loss of energy for separation.Until now, there is little literature about mathematical modeling of chemical-looping combustion using the computational fluid dynamics (CFD) approach. In this work, the reaction kinetic model of the fuel reactor (CaSO4+ H2) is developed by means of the commercial code FLUENT and the effects of partial pressure of H2 (concentration of H2) on chemical looping combustion performance are also studied. The results show that the concentration of H2 could enhance the CLC performance.

Review of Computational Fluid Dynamics Studies on Chemical Looping Combustion

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Yali Shao ◽  
Ramesh K. Agarwal ◽  
Xudong Wang ◽  
Baosheng Jin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Flow Process ◽  
Gas Leakage ◽  
Fuel Reactor ◽  
Energy Penalty

Abstract Chemical looping combustion (CLC) is an attractive technology to achieve inherent CO2 separation with low energy penalty. In CLC, the conventional one-step combustion process is replaced by two successive reactions in two reactors, a fuel reactor (FR) and an air reactor (AR). In addition to experimental techniques, computational fluid dynamics (CFD) is a powerful tool to simulate the flow and reaction characteristics in a CLC system. This review attempts to analyze and summarize the CFD simulations of CLC process. Various numerical approaches for prediction of CLC flow process are first introduced and compared. The simulations of CLC are presented for different types of reactors and fuels, and some key characteristics including flow regimes, combustion process, and gas-solid distributions are described in detail. The full-loop CLC simulations are then presented to reveal the coupling mechanisms of reactors in the whole system such as the gas leakage, solid circulation, redox reactions of the oxygen carrier, fuel conversion, etc. Examples of partial-loop CLC simulation are finally introduced to give a summary of different ways to simplify a CLC system by using appropriate boundary conditions.

scholarly journals LaFe1-xNix as a Robust Catalytic Oxygen Carrier for Chemical Looping Conversion of Toluene

2021 ◽  
Vol 12 (1) ◽  
pp. 391
Author(s):  
Haiming Gu ◽  
Juan Yang ◽  
Guohui Song ◽  
Xiaobo Cui ◽  
Miaomiao Niu ◽  
...  
Keyword(s):  
Oxygen Carrier ◽  
Fixed Bed ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Carbon Gasification ◽  
Syngas Production ◽  
Toluene Conversion ◽  
Substituted Ferrite ◽  
Tar Model Compound ◽  
H2 Yield

Chemical looping biomass gasification is a novel technology converting biomass into syngas, and the selection of oxygen carrier is key for efficient tar conversion. The performance of LaFe1-xNix as a robust catalytic oxygen carrier was investigated in the chemical looping conversion of toluene (tar model compound) into syngas in a fixed bed. LaM (M = Fe, Ni, Mn, Co, and Cu) was initially compared to evaluate the effect of transition metal on toluene conversion. LaFe (partial oxidation) and LaNi (catalytic pyrolysis) exhibited better performance in promoting syngas production than other oxygen carriers. Therefore, Ni-substituted ferrite LaFe1-xNix (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) was further developed. The effects of Ni-substitution, steam/carbon ratio (S/C), and temperature on toluene conversion into C1 and H2 were evaluated. Results showed that the synergistic effect of Fe and Ni promoted toluene conversion, improving H2 yield yet with serious carbon deposition. Steam addition promoted toluene steam reforming and carbon gasification. With S/C increasing from 0.8 to 2.0, the C1 and H2 yield increased from 73.9% to 97.5% and from 197.7% to 269.6%, respectively. The elevated temperature favored toluene conversion and C1 yield. LaFe0.6Ni0.4 exhibited strong reactivity stability during toluene conversion at S/C = 1.6 and 900 °C.

scholarly journals Workflow for computational fluid dynamics modeling of fixed‐bed reactors packed with metal foam pellets: Hydrodynamics

AIChE Journal ◽  
2021 ◽  
Author(s):  
Ginu R. George ◽  
Marina Bockelmann ◽  
Leonhard Schmalhorst ◽  
Didier Beton ◽  
Alexandra Gerstle ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Metal Foam ◽  
Fixed Bed ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Fixed Bed Reactors

scholarly journals Kinetic Behavior of Fabricated CuO/ZrO2 Oxygen Carriers for Chemical Looping Oxygen Uncoupling

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2156
Author(s):  
Young Ku ◽  
Chia-Wei Chang ◽  
Shr-Han Shiu ◽  
Hsuan-Chih Wu ◽  
Niels Michiel Moed
Keyword(s):  
Elevated Temperatures ◽  
Cupric Oxide ◽  
Oxygen Carrier ◽  
Fixed Bed ◽  
Reduction Rate ◽  
Fixed Bed Reactor ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Redox Cycles ◽  
Reduction And Oxidation

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO2 oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu2O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu2O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO2 particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe’ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO2, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 °C.

Effect of Fuel and Oxygen Carriers on the Hydrodynamics of Fuel Reactor in a Chemical Looping Combustion System

2013 ◽  
Author(s):  
Atal B. Harichandan ◽  
Tariq Shamim
Keyword(s):  
Oxygen Carrier ◽  
Bubble Formation ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Calcium Sulfide ◽  
Oxygen Carriers ◽  
Fuel Reactor ◽  
Gas Interactions ◽  
Kinetics Of ◽  
Good Agreement

The hydrodynamics of fuel reactor in a chemical looping combustion (CLC) system has been analyzed by using a multiphase CFD-based model with solid-gas interactions and chemical reactions. In this paper, the fuel reactors of two CLC systems are numerically simulated independently by using hydrogen with calcium sulfide as oxygen carrier, and methane with nickel as oxygen carrier in similar conditions. Kinetic theory of granular flow has been adopted. Conservation of mass, momentum and species equations, and reaction kinetics of oxygen carriers are used for the numerical calculation. The present results obtained are in good agreement with the experimental and numerical results available in open literature. The bubble hydrodynamics in both the fuel reactors are analyzed. The salient features of bubble formation, rise and burst are prominent in hydrogen-fueled reactor as compared to methane-fueled reactor. The fuel conversion rate is found to be larger in the case of hydrogen-fueled reactor.

One Based Magnetic Oxygen Carrier Solid Fuel Chemical Looping Combustion System Simulation

2013 ◽  
Vol 800 ◽  
pp. 454-458
Author(s):  
Wen Yan Li ◽  
Ming Zhong Gao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Combustion System ◽  
Cold Flow ◽  
Fundamental Understanding ◽  
Computational Fluid Dynamics Cfd ◽  
Scientific Significance

In this paper, Computational Fluid Dynamics (CFD) was used to simulate the magnetic device for the separation of Fe-base oxygen carrier in chemical-looping combustion system. The simulation was based on the Euler multiphase flow model and the k-ε turbulence model, which uses UDF programming to increase volume source phase. Here, commercial computational fluid dynamics software fluent platform was used to build the air reactor cold flow mathematical model, magnetic field under the conditions of different flow conditions were added for separating the Fe3O4 and Fe2O3. And the simulation results has an important understanding of the process of scientific significance, and will promote the fundamental understanding and applications of the Fe-base oxygen carrier.

Effects of ZnO Addition on Fe2O3/Al2O3 Oxygen Carriers on CH4 Reduction for Chemical Looping Combustion

2016 ◽  
Vol 872 ◽  
pp. 196-200
Author(s):  
Sujinda Thongsermsuk ◽  
Benjapon Chalermsinsuwan ◽  
Prapan Kuchonthara ◽  
Pornpote Piumsomboon
Keyword(s):  
Oxygen Carrier ◽  
Synergetic Effect ◽  
Fixed Bed ◽  
Reduction Process ◽  
Fixed Bed Reactor ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Fuel Gas ◽  
Physical Mixing

Fe2O3/Al2O3/ZnO oxygen carriers with small content ZnO (5 wt% to 10 wt%) were prepared by physical mixing method and were evaluated its capability as an oxygen carrier in a chemical looping combustion. The combustion was conducted by using CH4 as a fuel gas. The reduction process of Fe2O3/Al2O3/ZnO oxygen carrier was carried out in a fixed bed reactor. The solid reduction products were characterized by X-ray diffraction (XRD) and Scanning Electron Microscope with EDS Attachment (SEM-EDS). The results show that the reactivity of Fe2O3/Al2O3/ZnO oxygen carriers is greater than that of Fe2O3/Al2O3 which is implied the synergetic effect between ZnO and Fe2O3. XRD results show that the iron oxide in the oxygen carriers is reduced to metallic iron. SEM-EDS also shows that the iron agglomeration is prevented. Consequently, the suitable content of ZnO in oxygen carriers is ranged from 5 wt% to 10 wt%.

Effect of Fuel and Oxygen Carriers on the Hydrodynamics of Fuel Reactor in a Chemical Looping Combustion System

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Atal Bihari Harichandan ◽  
Tariq Shamim
Keyword(s):  
Oxygen Carrier ◽  
Bubble Formation ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Fuel Reactor ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Interactions ◽  
Kinetics Of ◽  
Good Agreement

The hydrodynamics of a fuel reactor in a chemical looping combustion (CLC) system is analyzed by using a multiphase two-dimensional computational fluid dynamics (CFD) model that involves solid–gas interactions and chemical reactions. The study compares the fuel reactors of two CLC systems numerically by using hydrogen with calcium sulfide as an oxygen carrier, and methane with nickel as an oxygen carrier in similar conditions. Kinetic theory of granular flow has been adopted. The model considers the conservation equations of mass, momentum and species, and reaction kinetics of oxygen carriers. The results obtained are in good agreement with the experimental and numerical results available in open literature. The bubble hydrodynamics in both the fuel reactors are analyzed. The salient features of the bubble formation, rise, and burst are more prominent in the hydrogen-fueled reactor as compared to the methane-fueled reactor. The fuel conversion rate is found to be larger for the hydrogen-fueled reactor.

Sign in / Sign up

Export Citation Format

Share Document