Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 179) Show all publications
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
Show others...
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
Show others...
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
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
Show others...
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
Wang, S., Persson, H., Weihong, Y. & Jönsson, P. (2018). Effect of H2 as Pyrolytic Agent on the Product Distribution during Catalytic Fast Pyrolysis of Biomass Using Zeolites. Energy & Fuels
Open this publication in new window or tab >>Effect of H2 as Pyrolytic Agent on the Product Distribution during Catalytic Fast Pyrolysis of Biomass Using Zeolites
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029Article in journal (Refereed) Published
Abstract [en]

Bio-oil generated from catalytic fast pyrolysis or hydrotreating processes represents one of the most promising alternatives to liquid fossil fuels. The use of H2 as carrier gas in the pyrolysis of biomass requires further research to study the catalytic fast pyrolysis reactions in the case of using reactive atmosphere. In this work, pyrolysis experiments with lignocellulosic biomass have been performed in a fixed bed reactor in H2 and N2 atmospheres with/without HZSM-5 additions to investigate the influence of the pyrolytic agents during fast pyrolysis of biomass and upgrading of pyrolytic vapors over a zeolitic catalyst. It was found that in a H2 atmosphere, H2 was consumed in both noncatalytic and catalytic pyrolysis processes, respectively. Higher yields of nonaqueous liquids and permanent gases are obtained in a H2 atmosphere compared to a N2 atmosphere. A catalytic pyrolysis process using HZSM-5 in a H2 atmosphere increased the production of polymer aromatic hydrocarbons and suppressed the production of monomer aromatic hydrocarbons compared to similar tests performed in a N2 atmosphere. The results show an overall increased activity of HZSM-5 in the reactive H2 atmosphere compared to a N2 atmosphere.

Keywords
biomass, pyrolysis, hydrogen, HZSM-5, 生物质, 生物燃料, HZSM-5, 催化裂解, 氢气
National Category
Bioenergy Chemical Engineering Biochemicals
Research subject
Chemical Engineering; Energy Technology; Biotechnology
Identifiers
urn:nbn:se:kth:diva-232341 (URN)10.1021/acs.energyfuels.8b01779 (DOI)000442448300052 ()2-s2.0-85049616561 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 2018-07-20

Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2018-09-07Bibliographically approved
Han, T., Sophonrat, N., Evangelopoulos, P., Persson, H., Weihong, Y. & Jönsson, P. (2018). Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin. Journal of Analytical and Applied Pyrolysis, 33, 162-168
Open this publication in new window or tab >>Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin
Show others...
2018 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 33, p. 162-168Article in journal (Refereed) Published
Abstract [en]

Sulfonated Kraft lignin, the most available commercial lignin of today, has high sulfur content due to the extraction and the subsequent sulfonation processes. In this work, the evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin has been studied. Fast Pyrolysis experiments have been done using Py-GC/MS. It is found that main sulfur-containing products in the pyrolytic vapors are present as the following small molecular compounds: H2S, SO2, CH3SH, CH3SCH3, and CH3SSCH3. This indicates that sulfur-containing radicals preferentially combine with the other small radicals such as H and CH3 during fast pyrolysis process. Sulfur is suggested to be mainly present as sulfite (SO3) and sulfide (S) in the sulfonated Kraft lignin. Sulfite that is incorporated into lignin during the sulfonation process mainly result in the formation of SO2. The nature of the sulfur links created during the Kraft pulping process is difficult to determine, but they are supposed to mainly exist in form of sulfide (S) bonds, which lead to the formation of H2S, CH3SH, CH3SCH3 and CH3SSCH3.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Chemical Engineering Materials Engineering
Identifiers
urn:nbn:se:kth:diva-229683 (URN)10.1016/j.jaap.2018.04.006 (DOI)000435747900020 ()2-s2.0-85045121473 (Scopus ID)
Funder
Swedish Research Council Formas
Note

QC 20180611

Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-07-23Bibliographically approved
Wan, W., Engvall, K., Yang, W. & Möller, B. F. (2018). Experimental and modelling studies on condensation of inorganic species during cooling of product gas from pressurized biomass fluidized bed gasification. Energy, 153, 35-44
Open this publication in new window or tab >>Experimental and modelling studies on condensation of inorganic species during cooling of product gas from pressurized biomass fluidized bed gasification
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 153, p. 35-44Article in journal (Refereed) Published
Abstract [en]

In a biomass gasification process, condensation of inorganic species can cause problems such as corrosion and deposition on the downstream equipment. In this work, in order to investigate the condensation of inorganics during the gas cooling step of the biomass gasification system, both experimental and modelling studies were conducted. Experiments were performed on a pilot-scale steam/oxygen blown fluidized bed gasification facility. A CO2 cooled probe was located at the head of a filter to condense inorganic species. Five thermocouples were used to monitor the probe temperature profile. Deposits on the probe were characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to analyze the elemental composition of deposits. A process model based on the local chemical and phase equilibriums was developed using software SimuSage to predict both release and condensation of inorganics. A customized thermodynamic database extracted from the FactSage 7.1 was used during model calculations. Two cases including with and without addition of bed material were calculated. Results show that the identified elemental compositions of deposit under different gas cooling temperatures reasonably agree with the elemental compositions predicted by model calculations. This demonstrates that the established model and the customized thermodynamic data are valid. A large amount of carbon is identified in the deposit of low temperature probe sections, which may come from the condensed tar. Additionally, a temperature window is found, where melts are formed during gas cooling.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Biomass, Inorganics, Condensation, Gasification
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-234209 (URN)10.1016/j.energy.2018.04.031 (DOI)000436651100005 ()2-s2.0-85046675283 (Scopus ID)
Note

QC 20180905

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-11-29Bibliographically approved
Persson, H., Han, T., Xia, W., Evangelopoulos, P. & Weihong, Y. (2018). Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment. Energy, 154, 346-351
Open this publication in new window or tab >>Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment
Show others...
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 154, p. 346-351Article in journal (Refereed) Published
Abstract [en]

The thermal properties of cellulose, hemicellulose and lignin can be utilized to improve the characteristics of pyrolysis liquids. In this study, a concept of stepwise pyrolysis to fractionate the liquid based on the thermal properties of the biomass constituents was investigated. Lignocellulosic biomass was thermally treated in two steps: 200–300 °C followed by 550 °C. Derived liquids were studied for GC/MS analysis, water content, acid concentration and a solvent extraction method. Pyrolytic liquid derived from 550 °C after treatment at lower temperatures have a higher relative composition of phenolic compounds compared to one-step pyrolysis (increased from 58 to 90% of GC/MS peak area). Also, compounds known to promote aging, such as acids and carbonyl compounds, are derived at lower temperatures which may suppress aging in the liquid derived downstream at 550 °C. For liquids derived at 550 °C, the total acid number was reduced from 125 in one-step treatment to 14 in two-step treatment. Overall, no significant difference in the total liquid yield (sum of the liquids derived in separated treatments) nor any variations in their collective composition compared to one-step treatment at 550 °C was observed, i.e. stepwise pyrolysis can be utilized for direct fractionation of pyrolytic vapors.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Pyrolysis Biomass Bio-oil Stepwise Fractionation
National Category
Engineering and Technology
Research subject
Chemical Engineering; Chemistry; Energy Technology; Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-227249 (URN)10.1016/j.energy.2018.04.150 (DOI)000436886200033 ()2-s2.0-85046167007 (Scopus ID)
Funder
Swedish Energy Agency, 33284-2Swedish Energy Agency, 39449-1
Note

QC 20180522

Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2019-09-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1837-5439

Search in DiVA

Show all publications