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Persson, H. & Yang, W. (2019). Catalytic pyrolysis of demineralized lignocellulosic biomass. Fuel, 252, 200-209
Open this publication in new window or tab >>Catalytic pyrolysis of demineralized lignocellulosic biomass
2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 252, p. 200-209Article in journal (Refereed) Published
Abstract [en]

The effect of ash removal pre-treatment of lignocellulosic biomass prior to catalytic pyrolysis for producingbiofuels was investigated. Non-catalytic and catalytic pyrolysis of demineralized and raw biomass was performedin Py-GC/MS and bench-scale experiments to study the performance of in-bed and ex-bed upgrading. Pretreatedbiomass shows a significant increase in the organic liquid yield in experiments performed at 600 °C: from31 to 42 wt% compared to raw biomass, as well as a significant reduction of char yield. The performance of inbedcatalytic pyrolysis of pre-treated biomass over HZSM-5 is limited compared to the corresponding raw material.However, ex-bed catalytic pyrolysis of pre-treated biomass at 600 °C results in an overall increased yield ofBTX compounds. Pyrolysis vapors from pre-treated biomass present a suitable composition for catalytic upgradingafter secondary vapor-phase reactions. Additionally, demineralization reduces the total acid number ofderived liquids in catalytic and non-catalytic pyrolysis.

Keywords
Biomass Pyrolysis pre-treatment demineralization catalyst hzsm-5
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-250262 (URN)10.1016/j.fuel.2019.04.087 (DOI)000470113800020 ()2-s2.0-85064520274 (Scopus ID)
Funder
Swedish Energy Agency, 47971-1
Note

QC 20190516

Available from: 2019-04-26 Created: 2019-04-26 Last updated: 2019-09-17Bibliographically approved
Han, T., Ding, S., Yang, W. & Jönsson, P. (2019). Catalytic pyrolysis of lignin using low-cost materials with different acidities and textural properties as catalysts. Chemical Engineering Journal, 373, 846-856
Open this publication in new window or tab >>Catalytic pyrolysis of lignin using low-cost materials with different acidities and textural properties as catalysts
2019 (English)In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 373, p. 846-856Article in journal (Refereed) Published
Abstract [en]

Catalytic fast pyrolysis of lignin was performed using low-cost materials with different acidities and textural properties as catalysts in the present work. The main focus is to understand the role of low-cost catalysts in the fast pyrolysis of lignin. The four most commonly used low-cost catalysts, ilmenite (FeTiO3), bentonite (Al-Si-OH), activated carbon (AC) and red mud (RM), were selected. The results show that bentonite, red mud and activated carbon effectively enhance the dehydration reaction, which is regarded as the dominant way to eliminate oxygen during the pyrolysis process, due to the existence of strong acidic sites. However, only activated carbon is found to be effective in promoting the production of monocyclic aromatic hydrocarbons (MAHs). Two metallic catalysts, i. e., bentonite and red mud, have strong acidities but quite low surface areas and less porous structures. Therefore, the dehydrated intermediates produced are especially easy to repolymerize to form char or coke without the restriction of obtaining a porous structure during the pyrolysis process. Activated carbon has not only a certain acidity but also a rich porous structure. Lignin fast pyrolysis-derived oxygenates can diffuse and react on the well-dispersed active sites within the pores of activated carbons. The catalytic performance of the activated carbon are supposed to be determined by the pore size. Only pores of similar size to lignin fast pyrolysis-derived oxygenates (0.6-1 nm) seems to be effective for the production of MAHs. Pores larger or smaller than lignin fast pyrolysis-derived oxygenates both tend to cause coke deposition rather than MAHs formation.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2019
Keywords
Low-cost catalysts, Lignin, Fast pyrolysis, Deoxygenation, Dehydration
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-255169 (URN)10.1016/j.cej.2019.05.125 (DOI)000471682900081 ()2-s2.0-85065989283 (Scopus ID)
Note

QC 20190904

Available from: 2019-09-04 Created: 2019-09-04 Last updated: 2019-09-04Bibliographically approved
Persson, H., Duman, I., Wang, S., Pettersson, L. & Yang, W. (2019). Catalytic pyrolysis over transition metal-modified zeolites: a comparative study between catalyst activity and deactivation. Journal of Analytical and Applied Pyrolysis, 138, 54-61
Open this publication in new window or tab >>Catalytic pyrolysis over transition metal-modified zeolites: a comparative study between catalyst activity and deactivation
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2019 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 138, p. 54-61Article in journal (Refereed) Published
Abstract [en]

The utilization of metal-doped zeolites in catalytic pyrolysis of biomass is a well-known approach to promote the formation of certain compounds. One major technical issue of using zeolites in biomass pyrolysis processes is their rapid deactivation due to coke formation. However, little is known about how metal-doping influences the characteristics of coking, such as coking rate and its composition.

In this study, four different materials were experimentally evaluated based on their catalytic activity and coking characteristics: HZSM-5, Fe/ZSM-5, Ni/ZSM-5 and FeNi/ZSM-5. The materials were prepared and characterized followed by screening in a bench-scale setup for in-situ catalytic pyrolysis. The mass balance and composition of pyrolysis products including catalyst coke were analyzed.

It was found that metal-doping increases the concentration of aromatic hydrocarbons in the liquid product from 59.0 to 82.8 % of GC/MS peak area, especially monoaromatic hydrocarbons (MAHs) and naphthalenes. Fe mainly promotes MAHs whereas Ni additionally promotes naphthalenes. FeNi/ZSM-5 enhances the production of both compound groups as well as further reducing the total acid number (TAN). Regarding the catalyst coke, metal-doped catalysts present an increased concentration of aromatic hydrocarbons in terms of MAHs, naphthalenes and polyaromatic hydrocarbons. For each catalyst, the chemical composition of catalyst coke reflects the catalyst’s activity seen in vapor upgrading. A reaction pathway based on the observed catalyst activities of metal-doped ZSM-5 and HZSM-5 is proposed.

The results also show that metal-doping of catalysts increases the formation of catalyst coke, mainly due to a higher concentration of strong acid sites. Also, the rate of coking is dependent on the strength of acid sites, where the strength correlates with the severity of coking. The coke yield was seen to increase from 3.5 wt% in the case of HZSM-5 to maximum 7.2 wt% over Fe/ZSM-5. However, the metal-doping of catalysts reduces the temperature of catalyst regeneration and catalyzes the oxidation of coke. Overall, this work presents a comparative study between catalyst activity and deactivation during thermochemical conversion of biomass.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Engineering and Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-239877 (URN)10.1016/j.jaap.2018.12.005 (DOI)000457854800006 ()2-s2.0-85059121054 (Scopus ID)
Note

QC 20181206

Available from: 2018-12-04 Created: 2018-12-04 Last updated: 2019-09-17Bibliographically approved
Han, T., Sophonrat, N., Tagami, A., Sevastyanova, O., Mellin, P. & Yang, W. (2019). Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem. Fuel, 235, 1061-1069
Open this publication in new window or tab >>Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem
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2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, p. 1061-1069Article in journal (Refereed) Published
Abstract [en]

Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Hydrolysis lignin (HL), Kraft lignin (KL), Melting properties, Structure, Crystal structure, Fluidization, Heat treatment, Hydrolysis, Melting, Pulp manufacture, Pyrolysis, Structure (composition), Temperature, After-heat treatment, Bio-ethanol production, Crosslinked structures, Elemental compositions, Hydrolysis lignins, Kraft lignin, Pyrolysis temperature, Lignin
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-236342 (URN)10.1016/j.fuel.2018.08.120 (DOI)000447791900105 ()2-s2.0-85052512069 (Scopus ID)
Funder
Swedish Research Council Formas
Note

QC 20181108

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2018-11-08Bibliographically approved
Zaini, I. N., Lopez, C. G., Pretz, T., Yang, W. & Jönsson, P. (2019). Characterization of pyrolysis products of high-ash excavated-waste and its char gasification reactivity and kinetics under a steam atmosphere. Waste Management, 97, 149-163
Open this publication in new window or tab >>Characterization of pyrolysis products of high-ash excavated-waste and its char gasification reactivity and kinetics under a steam atmosphere
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2019 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 97, p. 149-163Article in journal (Refereed) Published
Abstract [en]

The focus of this study is the pyrolysis and gasification of Refuse Derived Fuel (RDF) and fine fractions recovered from the excavation of landfill waste, with an emphasize on the characterization of the reactivity and kinetics of the char-steam gasification. The results from the pyrolysis tests demonstrated that CO and CO2 are the main produced gases during the pyrolysis of the finer fraction of landfill waste. This might be caused by the accumulation of degraded organic materials. The oil products from the pyrolysis of landfill waste were dominated by the derivative products of plastics such as styrene, toluene, and ethylbenzene. The chars obtained from the pyrolysis process were gasified under steam and steam/air atmospheres at temperatures between 800 and 900 degrees C by using thermogravimetry. The results from the gasification tests demonstrated that the char reactivity was mainly affected by the amount ratio between catalytic elements (K, Ca, Na, Mg, and Fe) over the inhibitor elements (Si, Al, and Cl), as well as the ash amount in the char. The results showed that char from the fine fraction of landfill waste has a higher reactivity than the RDF fraction, due to the high content of catalytic metal elements. These results suggest the use of a smaller sieve opening size for landfill waste separation processes may produce waste fuels with a high reactivity during gasification. Further, based on the thermogravimetric data, the kinetic parameters of landfill waste char gasification were calculated to have activation energies ranging from 54 to 128 kJ/mol. Author(s). Published by Elsevier Ltd.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Steam gasification, RDF, Municipal solid waste, Thermogravimetry analysis, Landfill mining
National Category
Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-261025 (URN)10.1016/j.wasman.2019.08.001 (DOI)000485213500018 ()31447022 (PubMedID)2-s2.0-85070414215 (Scopus ID)
Note

QC 20191002

Available from: 2019-10-02 Created: 2019-10-02 Last updated: 2019-10-02Bibliographically approved
Sophonrat, N., Sandström, L., Svanberg, R., Han, T., Dvinskikh, S., Lousada, C. M. & Yang, W. (2019). Ex Situ Catalytic Pyrolysis of a Mixture of Polyvinyl Chloride and Cellulose Using Calcium Oxide for HCl Adsorption and Catalytic Reforming of the Pyrolysis Products. Industrial & Engineering Chemistry Research, 58(31), 13960-13970
Open this publication in new window or tab >>Ex Situ Catalytic Pyrolysis of a Mixture of Polyvinyl Chloride and Cellulose Using Calcium Oxide for HCl Adsorption and Catalytic Reforming of the Pyrolysis Products
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2019 (English)In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 58, no 31, p. 13960-13970Article in journal (Refereed) Published
Abstract [en]

In the context of chemical recycling of mixed plastics and paper, multitemperature step pyrolysis has shown good potential for the separation of oxygenated products from hydrocarbons. Here, we report results of an investigation of the first pyrolysis step at low temperature, which involves the dehydrochlorination of polyvinyl chloride (PVC) and the pyrolysis of cellulose, the main component of paper. Calcium oxide (CaO), selected for its chloride adsorption ability and its catalytic activity on biooil deoxygenation, was used for upgrading the downstream products from the pyrolysis. Additionally, we studied the performance of CaO for the simultaneous adsorption of HCl and for reforming cellulose pyrolysates in the temperature range of 300-600 degrees C with feedstock to CaO ratios of 1:0.2, 1:0.4, and 1:1. It was found that the suitable catalytic temperature for HCl and acetic acid adsorption is lower than 400 degrees C. This is due to the desorption of HCl from CaCl2 and Ca(OH)Cl in the presence of water and CO2 at 400 degrees C and higher. A larger amount of CaO resulted in a more efficient reduction of acids and the organic liquids were found to have lower amounts of oxygen. A comparison between the cases of neat and mixed feedstock showed that pyrolysis of mixed feedstock produced more water, H-2, CO, and polycyclic aromatic hydrocarbons (PAHs) when compared to the case of neat materials over CaO.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-257448 (URN)10.1021/acs.iecr.9b02299 (DOI)000480496100016 ()2-s2.0-85071301059 (Scopus ID)
Note

QC 20190830

Available from: 2019-08-30 Created: 2019-08-30 Last updated: 2019-09-04Bibliographically approved
Ratnasari, D. K., Yang, W. & Jönsson, P. (2019). Kinetic Study of an H-ZSM-5/Al MCM-41 Catalyst Mixture and Its Application in Lignocellulose Biomass Pyrolysis. Energy & Fuels, 33(6), 5360-5367
Open this publication in new window or tab >>Kinetic Study of an H-ZSM-5/Al MCM-41 Catalyst Mixture and Its Application in Lignocellulose Biomass Pyrolysis
2019 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, no 6, p. 5360-5367Article in journal (Refereed) Published
Abstract [en]

The use of H-ZSM-S and Al MCM-41 in a two-stage system of mesoporous and microporous catalysts has been proved to improve the quality of bio-oil. Information about biomass pyrolysis kinetics is important to evaluate biomass as a feedstock for fuel or chemical production as well as efficient design and control of thermochemical processes. In this study, the catalytic pyrolysis kinetics of lignocellulose biomass with a mixed catalyst of H-ZSM-5 and Al-MCM-41 at different ratios is analyzed. The derived activation energies are determined using the Coats-Redfern model and an Avrami mechanism for first order chemical reactions (A1, F1). Bench-scale experiments as well as quantifications of the resulted benzene, toluene, and xylene (BTX) yields have also been investigated. The thermogravimetric analysis DTG results show that the presence of catalyst mixtures has significant effects on the fractions of volatile matter from lignocellulose biomass. Reactivity profiles have been obtained in the temperature range of 180 to 360 degrees C. The results show that the energy activation for lignocellulose biomass at a heating rate of 10 K min(-1) is 134.64 kJ mol(-1) and that the value decreases when using catalysts. However, when the heating rate is increased, the activation energy from the catalytic experiments is 6.3-66.0% higher than that from the biomass pyrolysis experiment. This is due to the production of coke. Overall, a H-ZSM-5/Al MCM-41 ratio of 3:1 is found to be the best catalyst ratio in cracking hemicellulose and cellulose compared to other catalyst mixtures that were studied. The same catalyst ratio also attains the best interaction, in terms of a BTX product selectivity. The optimum activity of this catalyst mixture is reached at a temperature of 500 degrees C.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-255323 (URN)10.1021/acs.energyfuels.9b00866 (DOI)000472800900065 ()2-s2.0-85066907499 (Scopus ID)
Note

QC 20190807

Available from: 2019-08-07 Created: 2019-08-07 Last updated: 2019-08-07Bibliographically approved
Gomez, R. Y., Nuran, Z. I., Yang, W. & Helsen, L. (2019). Landfill solid waste-based syngas purification by a hybrid pulsed corona plasma unit. In: European Biomass Conference and Exhibition Proceedings: . Paper presented at 27th European Biomass Conference and Exhibition, EUBCE 2019; Lisbon; Portugal; 27 May 2019 through 30 May 2019 (pp. 520-522). ETA-Florence Renewable Energies
Open this publication in new window or tab >>Landfill solid waste-based syngas purification by a hybrid pulsed corona plasma unit
2019 (English)In: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, p. 520-522Conference paper, Published paper (Refereed)
Abstract [en]

Gasification of excavated Municipal Solid Waste (MSW) for energy and materials recovery has been seen as a solution for current energetic, environmental and land availability issues. However, it poses many technological challenges, and among them the most difficult is to obtain of a tar-free syngas. In this work, two set of experiments were performed in order to obtain a syngas from MSW with a low tar content. In the first stage, MSW gasification was performed in order to identify the tar yield and composition at different temperatures using air and steam. After that, the most representative tar compound, naphthalene, was selected to perform tar cracking experiments in a pulsed corona plasma reactor able to operate from ambient temperature up to 1200ᵒC. The results of these experiments show that the pulsed corona plasma can enhance the tar thermal cracking reactions, reducing by 200ᵒC the temperature at which 100% of the naphthalene is converted.

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2019
Series
European Biomass Conference and Exhibition Proceedings, ISSN 2282-5819
Keywords
Clean synthesis gas, Gasification cleaning, Pulsed-corona plasma, Tar, Tar removal
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-258185 (URN)10.5071/27thEUBCE2019-2BO.6.2 (DOI)2-s2.0-85071067449 (Scopus ID)978-88-89407-19-6 (ISBN)
Conference
27th European Biomass Conference and Exhibition, EUBCE 2019; Lisbon; Portugal; 27 May 2019 through 30 May 2019
Note

QC 20191002

Available from: 2019-10-02 Created: 2019-10-02 Last updated: 2019-10-02Bibliographically approved
Wang, S., Persson, H., Yang, W. & Jönsson, P. (2019). Pyrolysis study of hydrothermal carbonization-treated digested sewage sludge using a Py-GC/MS and a bench-scale pyrolyzer. Fuel
Open this publication in new window or tab >>Pyrolysis study of hydrothermal carbonization-treated digested sewage sludge using a Py-GC/MS and a bench-scale pyrolyzer
2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, FuelArticle in journal (Refereed) Epub ahead of print
Abstract [en]

The disposal of digested sewage sludge is becoming a global problem. Hydrothermal carbonization (HTC) combined with the pyrolysis of digested sewage sludge was investigated by using a new conversion route for the exploitation of sewage sludge in energy applications. The thermochemical properties of the material were investigated by using HTC pre-treatments, thermogravimetric analyses, pyrolysis tests in Py-GC/MS and a bench-scale fixed bed reactor at temperatures of 450, 550, and 650 °C. It was found that the thermal decomposition of the hydrothermally treated digested sewage sludge takes place in a two-stage reaction. After pyrolysis, the ash in the sample was oxidized in the O2 atmosphere at 900 °C. Therefore, a new characterization method for determination of the non-oxdized ash content and fixed carbon content was proposed. The result from Py-GC/MS shows that the abundance of aromatic hydrocarbons in pyrolytic vapors present a positive correlation with increased temperature. In the bench-scale experiments, the highest HHV of the organic fraction was obtained at 650 °C as 38.46 MJ/kg.

National Category
Bioenergy
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-263710 (URN)10.1016/j.fuel.2019.116335 (DOI)
Funder
Swedish Research Council Formas
Note

QC 20191111

Available from: 2019-11-10 Created: 2019-11-10 Last updated: 2019-11-11Bibliographically approved
Salem, A. M., Zaini, I. N., Paul, M. C. & Yang, W. (2019). The evolution and formation of tar species in a downdraft gasifier: Numerical modelling and experimental validation. Biomass and Bioenergy, 130, Article ID 105377.
Open this publication in new window or tab >>The evolution and formation of tar species in a downdraft gasifier: Numerical modelling and experimental validation
2019 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 130, article id 105377Article in journal (Refereed) Published
Abstract [en]

Gasification is one of the most important methods for converting biomass to syngas currently used in energy production. However, tar content in syngas limits its direct use and thus requires additional removal techniques. The modelling of tar formation, conversion and destruction along a gasifier could give a wider understanding of the process and subsequently help in tar elimination and reduction. However, tar complexity, which contains hundreds of species, makes the modelling process hard and computationally intensive, because the chemistry of the formation and the combustion of many species have not yet been fully studied. In this work, a detailed kinetic model for the evolution and formation of tar from downdraft gasifiers, for the first-time, was built. The model incorporates four main tar species (benzene, naphthalene, toluene, and phenol) with a total of eighteen different kinetic reactions implemented in the code for every zone. Experimental work was carried out to initially validate the results of the kinetic code and found a good agreement. Further experiments were conducted at three different equivalence ratios (ERs) and at three different temperatures (800, 900, and 1100 °C). Sensitivity analysis was then carried out by the kinetic code to optimise the working parameters of a downdraft gasifier that led to a higher calorific value of syngas. The results reveal that a tar evolution model is more accurate for wood biomass materials and that using ER around 0.3, and moisture content levels lower than 10% lead to the production of higher value syngas with lower tar amounts.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Biomass gasification, Downdraft gasifiers, Gasification experiment, Numerical modelling, Tar species, Thermochemical kinetics, Biomass, Codes (symbols), Gasification, Kinetics, Naphthalene, Numerical models, Sensitivity analysis, Synthesis gas, Synthesis gas manufacture, Detailed kinetic modeling, Energy productions, Equivalence ratios, Experimental validations, Gasifiers, Working parameters, Tar, chemical reaction, chemistry, combustion, equipment, experimental study, model validation, modeling, moisture content, pollutant removal, reaction kinetics, thermochemistry
National Category
Chemical Process Engineering Organic Chemistry
Research subject
Energy Technology; Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-263501 (URN)10.1016/j.biombioe.2019.105377 (DOI)2-s2.0-85072519314 (Scopus ID)
Note

QC 20191202

Available from: 2019-12-02 Created: 2019-12-02 Last updated: 2019-12-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1837-5439

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