Transient Cold Flow Simulation of Fast-Fluidized Bed Air Reactor with Hematite as an Oxygen Carrier for Chemical Looping Combustion

Chemical looping combustion (CLC) is the most reliable carbon capture technology for curtailing CO2 insertion into the atmosphere. This paper presents the cold flow simulation results necessary to understand the hydrodynamic viability of the fast-fluidized bed air reactor. Hematite is selected as an oxygen carrier due to its easy availability and active nature during the reactions. The dense discrete phase model (DDPM) approach using the commercial software Ansys Fluent is applied in the simulation. An accurate and stable solution is achieved using the second-order upwind numerical scheme. A pressure difference of 150 kPa is obtained between the outlet and inlet of the selected air reactor, which is necessary for the movement of the particle. The stable circulating rate of hematite is achieved after 28 s of particle injection inside the air reactor. The results have been validated from the experimental results taken from the literature.

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Transient Cold Flow Simulation of a Fast Fluidized Bed Fuel Reactor for Chemical Looping Combustion

Coal and Biomass Gasification - Energy, Environment, and Sustainability ◽

10.1007/978-981-10-7335-9_13 ◽

2017 ◽

pp. 331-347

Author(s):

Ramesh K. Agarwal ◽

Mengqiao Yang ◽

Subhodeep Banerjee

Keyword(s):

Fluidized Bed ◽

Flow Simulation ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Cold Flow ◽

Fuel Reactor

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Transient Cold Flow Simulation of Fast Fluidized Bed Fuel Reactors for Chemical-Looping Combustion

Journal of Energy Resources Technology ◽

10.1115/1.4039415 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 5

Author(s):

Mengqiao Yang ◽

Subhodeep Banerjee ◽

Ramesh K. Agarwal

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Volume Fraction ◽

Particle Density ◽

Flow Simulation ◽

Pilot Scale ◽

Industrial Scale ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Discrete Phase Model

Circulating fluidized bed in chemical-looping combustion (CLC) is a recent technology that provides great advantage for gas–solid interaction and efficiency. In order to obtain a thorough understanding of this technology and to assess its effectiveness for industrial scale deployment, numerical simulations are conducted. Computational fluid dynamics (CFD) simulations are performed with dense discrete phase model (DDPM) to simulate the gas–solid interactions. CFD commercial software ansysfluent is used for the simulations. Two bed materials of different particle density and diameter, namely the molochite and Fe100, are used in studying the hydrodynamics and particle behavior in a fuel reactor corresponding to the experimental setup of Haider et al. (2016, “A Hydrodynamic Study of a Fast-Bed Dual Circulating Fluidized Bed for Chemical Looping Combustion,” Energy Technol., 4(10), pp. 1254–1262.) at Cranfield University in the UK. Both the simulations show satisfactory agreement with the experimental data for both the static pressure and volume fraction at various heights above the gas inlet in the reactor. It is found that an appropriate drag law should be used in the simulation depending on the particle size and flow conditions in order to obtain accurate results. The simulations demonstrate the ability of CFD/DDPM to accurately capture the physics of circulating fluidized bed-based CLC process at pilot scale which can be extended to industrial scale projects.

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Syngas combustion characteristics of four oxygen carrier particles for chemical-looping combustion in a batch fluidized bed reactor

Korean Journal of Chemical Engineering ◽

10.1007/s11814-009-0089-7 ◽

2009 ◽

Vol 26 (2) ◽

pp. 523-527 ◽

Cited By ~ 10

Author(s):

Ho-Jung Ryu ◽

Dowon Shun ◽

Dal-Hee Bae ◽

Moon-Hee Park

Keyword(s):

Fluidized Bed ◽

Oxygen Carrier ◽

Fluidized Bed Reactor ◽

Combustion Characteristics ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Syngas Combustion

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A Pb/Zn Based Chemical Looping System for Hydrogen and Power Production With Carbon Capture

Volume 4: Cycle Innovations; Fans and Blowers; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine; Oil and Gas Applications ◽

10.1115/gt2011-46602 ◽

2011 ◽

Author(s):

Niall R. McGlashan ◽

Peter R. N. Childs ◽

Andrew L. Heyes

Keyword(s):

Power System ◽

Flue Gas ◽

Power Output ◽

Carbon Capture ◽

Oxygen Carrier ◽

Fluid Phase ◽

Chemical Looping Combustion ◽

Inlet Temperature ◽

Chemical Looping ◽

Lower Efficiency

This paper describes an extension of a novel, carbon-burning, fluid phase chemical looping combustion system proposed previously. The system generates both power and H2 with ‘inherent’ carbon capture using chemical looping combustion (CLC) to perform the main energy release from the fuel. A mixed Pb and Zn based oxygen carrier is used, and due to the thermodynamics of the carbothermic reduction of PbO and ZnO respectively, the system generates a flue gas which consists of a mixture of CO2 and CO. By product H2 is generated from this flue gas using the water-gas shift reaction (WGSR). By varying the proportion of Pb to Zn circulating in the chemical loop, the ratio of CO2 to CO can be controlled, which in turn enables the ratio between the amount of H2 produced to the amount of power generated to be adjusted. By this means, the power output from the system can be ‘turned down’ in periods of low electricity demand without requiring plant shutdown. To facilitate the adjustment of the Pb/Zn ratio, use is made of the two metal’s mutual insolubility, as this means they form in to two liquid layers at the base of the reduction reactor. The amount of Pb and Zn rich liquid drawn from the two layers and subsequently circulated around the system is controlled thereby varying the Pb/Zn ratio. To drive the endothermic reduction of ZnO formed in the oxidiser, hot Zn vapour is ‘blown’ into the reducer where it condenses, releasing latent heat. The Zn vapour to produce this ‘blast’ of hot gas is generated in a flash vessel fed with hot liquid metal extracted from the oxidiser. A mass and energy balance has been conducted for a power system, operating on the Pb/Zn cycle. In the analysis, reactions are assumed to reach equilibrium and losses associated with turbomachinery are considered; however, pressure losses in equipment and pipework are assumed to be negligible. The analysis reveals that a power system with a second law efficiency of between 62% and 68% can be constructed with a peak turbine inlet temperature of only ca. 1850 K. The efficiency varies as the ratio between power and H2 production varies, with the lower efficiency occurring at the maximum power output condition.

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Modeling of the Chemical Looping Combustion of Hard Coal and Biomass Using Ilmenite as the Oxygen Carrier

Energies ◽

10.3390/en13205394 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5394

Author(s):

Anna Zylka ◽

Jaroslaw Krzywanski ◽

Tomasz Czakiert ◽

Kamil Idziak ◽

Marcin Sosnowski ◽

...

Keyword(s):

Fluidized Bed ◽

Oxygen Carrier ◽

Experimental Tests ◽

Chemical Looping Combustion ◽

Hard Coal ◽

Chemical Looping ◽

Simulation Accuracy ◽

Energy Technologies ◽

Fuel Reactor ◽

Relative Errors

This paper presents a 1.5D model of a fluidized bed chemical looping combustion (CLC) built with the use of a comprehensive simulator of fluidized and moving bed equipment (CeSFaMB) simulator. The model is capable of calculating the effect of gas velocity in the fuel reactor on the hydrodynamics of the fluidized bed and the kinetics of the CLC process. Mass of solids in re actors, solid circulating rates, particle residence time, and the number of particle cycles in the air and fuel reactor are considered within the study. Moreover, the presented model calculates essential emissions such as CO2, SOX, NOX, and O2. The model was successfully validated on experimental tests that were carried out on the Fluidized-Bed Chemical-Looping-Combustion of Solid-Fuels unit located at the Institute of Advanced Energy Technologies, Czestochowa University of Technology, Poland. The model’s validation showed that the maximum relative errors between simulations and experiment results do not exceed 10%. The CeSFaMB model is an optimum compromise among simulation accuracy, computational resources, and processing time.

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