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

Energies ◽  
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.

Optimizing the Fuel Reactor for Chemical Looping Combustion

2003 ◽  
Author(s):  
Juan Ada´nez ◽  
Francisco Garci´a-Labiano ◽  
Luis F. de Diego ◽  
Ainhoa Plata ◽  
Javier Celaya ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Oxygen Carrier ◽  
Bubble Diameter ◽  
Operating Conditions ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Solid Contact ◽  
Fuel Reactor ◽  
Contact Efficiency

A mathematical model for a bubbling fluidized bed has been developed to optimize the performance of the fuel reactor in chemical looping combustion systems. This model considers both the hydrodynamic of the fluidized bed (dense bed and freeboard) and the kinetics of the oxygen carrier reduction. Although the model is valid for any of the possible oxygen carriers and fuels, the present work has been focused in the use of a carrier, CuO-SiO2, and CH4 as fuel. The shrinking core model has been used to define the particle behavior during their reduction. The simulation of the fuel reactor under different operating conditions was carried out to set the operating conditions and optimize the process. The effect of different design or operating variables as the bed height, the oxygen carrier/fuel ratio, and the gas throughput was analyzed. Finally, a sensitivity analysis to the solid reactivity, the bubble diameter, and to the gas/solid contact efficiency in the freeboard was done. At vigorous fluidization, solid present in the freeboard can strongly contribute to the gas conversion in the fuel reactor. However, the gas/solid contact efficiency in this zone must be determined for each particular case.

scholarly journals Cold Model Study of a 1.5 MWth Circulating Turbulent Fluidized Bed Fuel Reactor in Chemical Looping Combustion

2020 ◽  
Vol 34 (7) ◽  
pp. 8575-8586
Author(s):  
Hu Chen ◽  
Zhenshan Li ◽  
Xinglei Liu ◽  
Weicheng Li ◽  
Ningsheng Cai ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Cold Model ◽  
Model Study ◽  
Turbulent Fluidized Bed ◽  
Fuel Reactor

scholarly journals Use of ilmenite as an oxygen carrier in chemical looping combustion-batch and continuous dual fluidized bed investigation

2011 ◽  
Vol 4 ◽  
pp. 433-440 ◽  
Author(s):  
A.R. Bidwe ◽  
F. Mayer ◽  
C. Hawthorne ◽  
A. Charitos ◽  
A. Schuster ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Dual Fluidized Bed

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.

Chemical looping combustion of coal in a 5 kWth interconnected fluidized bed reactor using hematite as oxygen carrier

2015 ◽  
Vol 157 ◽  
pp. 304-313 ◽  
Author(s):  
Jinchen Ma ◽  
Haibo Zhao ◽  
Xin Tian ◽  
Yijie Wei ◽  
Sharmen Rajendran ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Oxygen Carrier ◽  
Fluidized Bed Reactor ◽  
Chemical Looping Combustion ◽  
Chemical Looping

Chemical-Looping Combustion of Hard Coal: Autothermal Operation of a 1 MWth Pilot Plant

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Peter Ohlemüller ◽  
Jan-Peter Busch ◽  
Michael Reitz ◽  
Jochen Ströhle ◽  
Bernd Epple
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Capture ◽  
Oxygen Carrier ◽  
Air Separation ◽  
Capture Efficiency ◽  
Chemical Looping Combustion ◽  
Hard Coal ◽  
Chemical Looping ◽  
Separation Unit ◽  
Autothermal Operation

Chemical-looping combustion (CLC) is an emerging carbon capture technology that is characterized by a low energy penalty, low carbon dioxide capture costs, and low environmental impact. To prevent the contact between fuel and air, an oxygen carrier is used to transport the oxygen needed for fuel conversion. In comparison to a classic oxyfuel process, no air separation unit is required to provide the oxygen needed to burn the fuel. The solid fuel, such as coal, is gasified in the fuel reactor (FR), and the products from gasification are oxidized by the oxygen carrier. There are promising results from the electrically heated 100 kWth unit at Chalmers University of Technology (Sweden) or the 1 MWth pilot at Technische Universität Darmstadt (Germany) with partial chemical-looping conditions. The 1 MWth CLC pilot consists of two interconnected circulating fluidized bed reactors. It is possible to investigate this process without electrically heating due to refractory-lined reactors and coupling elements. This work presents the first results of autothermal operation of a metal oxide CLC unit worldwide using ilmenite as oxygen carrier and coarse hard coal as fuel. The FR was fluidized with steam. The results show that the oxygen demand of the FR required for a complete conversion of unconverted gases was in the range of 25%. At the same time, the carbon dioxide capture efficiency was low in the present configuration of the 1 MWth pilot. This means that unconverted char left the FR and burned in the air reactor (AR). The reason for this is that no carbon stripper unit was used during these investigations. A carbon stripper could significantly enhance the carbon dioxide capture efficiency.

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