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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
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
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
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, 32(8), 8530-8536
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 1520-5029, Vol. 32, no 8, p. 8530-8536Article 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.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
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 20180720. QC 20191111

Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2019-11-11Bibliographically 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
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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
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
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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
Persson, H., Evangelopoulos, P., Svanberg, R. & Weihong, Y. (2017). Two-step pyrolysis of biomass to enhance the chemical stability of pyrolytic liquids. In: European Biomass Conference and Exhibition Proceedings 2017: . Paper presented at European Biomass Conference and Exhibition 2017 (pp. 1186-1189). ETA-Florence Renewable Energies, 7(25thEUBCE)
Open this publication in new window or tab >>Two-step pyrolysis of biomass to enhance the chemical stability of pyrolytic liquids
2017 (English)In: European Biomass Conference and Exhibition Proceedings 2017, ETA-Florence Renewable Energies , 2017, Vol. 7, no 25thEUBCE, p. 1186-1189Conference paper, Published paper (Refereed)
Abstract [en]

Aging of pyrolytic liquid during storage changes its chemical and physical properties. The reason for aging is the chemical instability of the liquid, which is not at thermodynamic equilibrium when quenched after pyrolysis. Compounds active in these reactions mainly derivatives from hemicellulose (e.g. acids and carbonyls). In this work, a two-step pyrolysis concept was investigated to separate these compounds in a lower temperature treatment step upstream a conventional pyrolyzer. Different temperatures of the lower temperature treatment was investigated with constant conditions of the conventional treatment. The total liquid yield derived did not vary from pyrolysis in one step. Results show that the two-step pyrolysis process significantly reduces the concentration of organic acids and carbonyls in the liquid product from the second pyrolyzer, which instead are found in the liquid from the lower temperature treatment. Also, the concentration of sugar derivatives from the second step treatment is increased with the temperature of the first step. However, a complete separation of aging active compounds is not possible without sacrificing partial fractions of others (lignin derivatives were found in the low-temperature treatment). By varying the temperature of the first step one can control the concentrations and the liquid yield from each step.

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2017
Series
European Biomass Conference and Exhibition Proceedings, ISSN 2282-5819 ; 2017
Keywords
Biomass, Chemical composition, Low temperature, Pyrolysis, Softwood, Torrefaction
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-224854 (URN)2-s2.0-85043793450 (Scopus ID)
Conference
European Biomass Conference and Exhibition 2017
Note

QC 20180327

Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2018-12-04Bibliographically approved
Persson, H., Gulshan, S., Svanberg, R. & Yang, W.Production of renewable aromatic hydrocarbons by ex-situ catalytic fast pyrolysis of biomass in a combined fluidized bed and fixed bed reactor system.
Open this publication in new window or tab >>Production of renewable aromatic hydrocarbons by ex-situ catalytic fast pyrolysis of biomass in a combined fluidized bed and fixed bed reactor system
(English)Manuscript (preprint) (Other academic)
Abstract [en]

An ex-situ catalytic fast pyrolysis lab-scale setup consisting of a fluidized bed pyrolyzer and a fixed bed catalytic reactor was experimentally evaluated. The effect of weight hourly space velocity was investigated in the range of 0.35-0.77 h-1 during 260 min of operation. A lower biomass feed rate over a fixed amount of catalyst results in a higher degree of vapor deoxygenation (from 71 to 79.5 wt%) as well as higher concentrations of aromatic hydrocarbons. The carbon conversion from biomass to upgraded liquids is negatively correlated with the aromatic concentrations. Online gas analysis present no significant changes in the catalytic performance during the operational time. The results of this study indicate that the difference in liquid deoxygenation observed when varying the biomass feed rate is dependent on the vapor concentration in the gas stream over the catalytic bed rather than being significantly affected by catalyst deactivation during operation.

Keywords
Catalytic pyrolysis; HZSM-5; fluidized bed; fixed bed; WHSV
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-259563 (URN)
Note

QC 20190918

Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-09-18Bibliographically approved
Evangelopoulos, P., Persson, H., Kantarelis, E. & Yang, W.Pyrolysis of waste electrical and electronic equipment (WEEE) on a single screw reactor for bromine free oil production.
Open this publication in new window or tab >>Pyrolysis of waste electrical and electronic equipment (WEEE) on a single screw reactor for bromine free oil production
(English)Manuscript (preprint) (Other academic)
Abstract [en]

This study focuses on pyrolysis on waste electrical and electronic equipment or WEEE as it is usually referred in the literature. A new auger reactor has been designed and tested with WEEE material. The performance of the reactor as well as the fate of the bromine has been investigated and evaluated in order to be used for designing of industrial process. The mass balance calculations performed for the tested cases of 400, 500 and 600 °C, showed a high gas yield (44%) at the temperature of 600 °C, which can be used to fulfil the process energy needs. At the low temperature of 400 °C the oil production reach its maximum yield, while the bromine content of the oil has also a maximum percentage of 0.5% wt. Several valuable compounds have been detected in the oil composition, which can be used either as fuels or for feedstock recycling.

Keywords
Pyrolysis, Screw reactor, WEEE, BRFs, brominated flame retardants
National Category
Materials Engineering Chemical Engineering Environmental Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-238645 (URN)
Note

QC 20181109

Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-09Bibliographically approved
Evangelopoulos, P., Arato, S., Persson, H., Kantarelis, E. & Yang, W. Reduction of brominated flame retardants (BFRs) in plastics from waste electrical and electronic equipment (WEEE) by solvent extraction and the influence on their thermal decomposition. Waste Management
Open this publication in new window or tab >>Reduction of brominated flame retardants (BFRs) in plastics from waste electrical and electronic equipment (WEEE) by solvent extraction and the influence on their thermal decomposition
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(English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456Article in journal (Refereed) In press
Abstract [en]

Consumption of electronics increases due to modern society’s growing needs, which leads to increasing generation of waste electrical and electronic equipment (WEEE). Recycling of WEEE has been a global concern during the last few decades because of the toxic compounds that are produced during recycling. Different recycling techniques have been adapted on a commercial scale in order to overcome this issue, but the recycling of WEEE still lacks the technology to treat different kinds of feedstocks and to maximise the recycling rates. Pyrolysis is an alternative that has not been commercialised yet. One of the challenges for the implementation of this technology is the toxic brominated organic compounds that can be found in the pyrolysis oils.

In this study, tetrabromobisphenol A (TBBPA), one of the major flame retardants, is reduced in three different WEEE fractions through solvent extraction as a treatment prior to pyrolysis. Two solvents have been experimentally investigated: isopropanol and toluene, the latter of which can be derived from pyrolysis oil. The results indicate that TBBPA was extracted during pre-treatment. Moreover, the total bromine content of WEEE material was reduced after the treatment with a maximum reduction of 36.5%. The pyrolysis experiments indicate that reduction of several brominated organic compounds was achieved in almost all the tested cases, and two brominated compounds (2,4,6-tribromophenol and 2,5-Dibromobenzo(b)thiophene) reached complete removal. Also, the thermal decomposition behaviour of the raw samples and the treated was investigated, showing that the reduction of TBBPA influences the decomposition by shifting the starting decomposition temperature.

Keywords
Tetrabromobisphenol A; BFRs; Pyrolysis; Soxhlet; WEEEE; e-waste
National Category
Environmental Management Other Materials Engineering Chemical Engineering
Research subject
Materials Science and Engineering; Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-238628 (URN)10.1016/j.wasman.2018.06.018 (DOI)000477786000017 ()2-s2.0-85048762620 (Scopus ID)
Note

QC 20181107

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2019-08-20Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2373-4950

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