Chemical looping combustion: A new low-dioxin energy conversion technology

Hua, Xiuning; Wang, Wei

doi:10.1016/j.jes.2014.09.044

Cited by 26 publications

(9 citation statements)

References 82 publications

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“…However, the indirect contact of the solid fuel with the O 2 greatly reduced the formation of Cl 2, and the use of ilmenite as the oxygen carrier was also found to generate the minimum amount of Cl 2 when compared with other oxygen carriers. 48 Hence, the formation of alkali metal chloride, which causes corrosion, will be greatly reduced.…”

Section: Results and Discussionmentioning

confidence: 99%

Process Modelling of Chemical Looping Combustion of Paper, Plastics, Paper/Plastic Blend Waste, and Coal

Yaqub

Oboirien

2020

ACS Omega

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Chemical looping combustion (CLC) is a novel carbon capture and storage technology that can be used in the proper disposal of municipal solid waste when used as a solid fuel. In this study, the results of the CLC of paper, plastics, and paper/plastic blends were compared with CLC of South African coal using Chemcad software. The simulation was done for two different CLC processes, namely, chemical looping oxygen uncoupling (CLOU) and in situ gasification CLC (IG-CLC). The results demonstrated that coal at 66% had a lower CO 2 yield than paper (86%) but a higher yield than all the plastic samples in CLOU (3356%) and an equal CO 2 yield in paper and all plastic samples in IG-CLC. Furthermore, coal had a lower CO 2 gas yield than all the optimum blends (72–85%) for CLOU and an equal yield with the entire paper/plastic blend in IG-CLC. On combustion efficiency, coal has a lower combustion efficiency at 80% than paper and polyvinyl chloride (PVC) at 90 and 96%, respectively, but a higher efficiency than other plastic samples that are between 30 and 70% in CLOU while in IG-CLC, it had a lower efficiency than paper, PVC, and polyethylene terephthalate and higher efficiency than high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene. For paper/plastic blends, coal has higher combustion efficiency than all the paper/plastic blends in both CLOU and IG-CLC processes except for the paper/PVC where the combustion efficiency was higher than coal.

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Section: Results and Discussionmentioning

confidence: 99%

Process Modelling of Chemical Looping Combustion of Paper, Plastics, Paper/Plastic Blend Waste, and Coal

Yaqub

Oboirien

2020

ACS Omega

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“…11 It can be found that chlorine sources (HCl and Cl 2 ) are the key factors for both high-temperature gas-phase conversion and low-temperature heterogeneous synthesis. Some researches revealed that solid fuels release chlorine mainly in the form of HCl 12 be converted into Cl 2 through Deacon reaction, 9 and the activity of Cl 2 is much higher than that of HCl, 10 thus promoting chlorination in the PCDD/F generation process.…”

Section: Introductionmentioning

confidence: 99%

“…It can be found that chlorine sources (HCl and Cl 2 ) are the key factors for both high-temperature gas-phase conversion and low-temperature heterogeneous synthesis. Some researches revealed that solid fuels release chlorine mainly in the form of HCl under high temperature conditions, but in the presence of O 2 , it can be converted into Cl 2 through Deacon reaction, and the activity of Cl 2 is much higher than that of HCl, thus promoting chlorination in the PCDD/F generation process. In terms of determining the PCDD/F generation pathway, most of research studies have been carried out for some specific generation pathways.…”

Section: Introductionmentioning

confidence: 99%

Function Pathways of CaO Decoration on the Internal Transformation of PCDD/Fs Isomers for Chemical Looping Combustion of Plastic Waste

et al. 2020

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The distribution characteristics of 17 toxic polychlorinated dibenzodioxin/furan (PCDD/F) isomers are closely related to their toxic equivalents, and hence, knowing the transformation and contribution pathways among PCDD/F isomers is the foundation of selectively regulating their isomer emissions. Based on the relevance of PCDD/F isomers, a pathway substitution (PTWS) prediction method among PCDD/F isomers was proposed and employed in this work. First, the accuracy of the PTWS prediction method was confirmed by taking the chemical looping combustion (CLC) of plastic waste (including Fe-based CLC and that with CaO decoration) experimental data as an example and comparing it with the existing position-substitution (PSTS) prediction method. The evaluation indexes include similarity (S), average percentage content error (C), and maximum percentage content error (Z). Second, the effects of CaO decoration on the single chlorine substitution pathway were compared by calculating the chlorine substitution probability. The results show three decreasing chlorine substitution probabilities for the main transformation pathways which are affected by CaO decoration. In addition, the PCDD/F percentage content migration pathway diagrams were drawn to further confirm the critical pathways that affect the distribution of PCDD/F isomers. Finally, the mean toxic equivalent migration situations of PCDD/Fs were calculated according to the toxic equivalents and chlorine substitution probabilities of PCDD/F isomers. The results showed that CaO decoration further reduced the chlorine substitution probability of 1,2,3,7,8-PeCDD, which was identified as the main reason for the increase of the mean toxic equivalents of PCDD, while it slightly altered the mean toxic equivalent for PCDFs. This study can provide a new theoretical basis for further exploring the low PCDD/F emission technology in the CLC process of plastic waste.

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“…This process includes reduction, water splitting and combustion steps, which are also referred to as chemical looping gasification [14] or chemical looping hydrogen generation [15]. Owing to the use of lattice oxygen in the oxygen carrier for combustion [16,17], less NOx and dioxins are produced [18][19][20][21] so that cleaner hydrogen can be achieved in this process.…”

Section: Introductionmentioning

confidence: 99%

The behaviour of multiple reaction fronts during iron (III) oxide reduction in a non-steady state packed bed for chemical looping water splitting

et al. 2017

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Owing to the unclear temporal and spatial variations of axial solid conversion in a packed bed using iron (III) oxide as an oxygen carrier, we directly observe these variations by means of a sub-layer approach. The results indicate that the behaviour of the multiple reaction fronts during iron (III) oxide reduction by CO or H2 within a packed bed for chemical looping water splitting (CLWS) is strongly dependent on the reaction temperature. When the reaction temperature is lower than the merging temperature, three reaction fronts, i.e., Fe2O3-Fe3O4, Fe3O4-Fe0.947O and Fe0.947O-Fe, and three product zones, i.e., Fe3O4, Fe0.947O and Fe, will appear in the packed bed. In contrast, when the reaction temperature is higher than the merging temperature, the Fe2O3-Fe3O4 and Fe3O4-Fe0.947O fronts merge, leading to the disappearance of the Fe3O4 zone. As a result, only the Fe2O3-Fe0.947O and Fe0.947O-Fe fronts, as well as Fe0.947O and Fe zones will appear in the packed bed. These reduction behaviours are verified by two breakthrough curves, one for T < Tm and one for T > Tm, from the thermodynamically controlled reduction of iron (III) oxide in the packed bed. The reaction front movement model, which is proposed based on the reduction behaviour, can be used to determine the maximum solid conversion of the reduction step, i.e., the thermodynamic limitation of the reduction step, in the packed bed CLWS. The maximum solid conversion can reach 0.409 for the CO case and 0.554 for the H2 case. The first discovery of both the behaviours of the reaction fronts movement and the thermodynamic limitations of the reduction step standardizes the criteria for both the oxygen carrier evaluation and the optimization of the operating conditions and provides theoretical support for scaling up the packed bed and developing new technology for packed bed CLWS

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Chemical looping combustion: A new low-dioxin energy conversion technology

Cited by 26 publications

References 82 publications

Process Modelling of Chemical Looping Combustion of Paper, Plastics, Paper/Plastic Blend Waste, and Coal

Process Modelling of Chemical Looping Combustion of Paper, Plastics, Paper/Plastic Blend Waste, and Coal

Function Pathways of CaO Decoration on the Internal Transformation of PCDD/Fs Isomers for Chemical Looping Combustion of Plastic Waste

The behaviour of multiple reaction fronts during iron (III) oxide reduction in a non-steady state packed bed for chemical looping water splitting

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