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Ding, S., Ge, Y., Kantarelis, E., Kong, X., Pettersson, J. B. .. & Engvall, K. (2024). Time-resolved alkali release during steam gasification of char in a fixed bed reactor. Fuel, 356, 129528, Article ID 129528.
Open this publication in new window or tab >>Time-resolved alkali release during steam gasification of char in a fixed bed reactor
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2024 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 356, p. 129528-, article id 129528Article in journal (Refereed) Published
Abstract [en]

In this study time-resolved char conversion and alkali release under steam gasification conditions were investigated using a fixed bed reactor. The behaviour of an industrial char and chars produced from straw and furniture waste was investigated. For woody chars, an increase in gasification reactivity is observed together with a notable alkali release as the gasification approaches completion (degree of conversion > 0.8). In contrast, straw char exhibited a decrease in conversion rate and alkali release throughout the gasification process, attributed to the formation of catalytically inactive potassium silicates inhibiting the catalytic role of alkali. Aerosol particles in the 0.01–22 µm size range are emitted during the char conversion. A fraction is formed by nucleation of alkali compounds and other condensable gases. A wide particle distribution that extends over the whole size range is also observed, and the particles are likely to consist of solid char fragments. The study concludes on the importance of alkali release, illustrating the difference in alkali release pattern for high and low ash char.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Aerosol, Alkali release, Biomass char, Gasification, Reactivity, Steam
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-337411 (URN)10.1016/j.fuel.2023.129528 (DOI)001081087500001 ()2-s2.0-85172021154 (Scopus ID)
Note

QC 20231003

Available from: 2023-10-03 Created: 2023-10-03 Last updated: 2023-10-31Bibliographically approved
Farah, E., Demianenko, L., Engvall, K. & Kantarelis, E. (2023). Controlling the Activity and Selectivity of HZSM-5 Catalysts in the Conversion of Biomass-Derived Oxygenates Using Hierarchical Structures: The Effect of Crystalline Size and Intracrystalline Pore Dimensions on Olefins Selectivity and Catalyst Deactivation. Topics in catalysis, 66(17-18), 1310-1328
Open this publication in new window or tab >>Controlling the Activity and Selectivity of HZSM-5 Catalysts in the Conversion of Biomass-Derived Oxygenates Using Hierarchical Structures: The Effect of Crystalline Size and Intracrystalline Pore Dimensions on Olefins Selectivity and Catalyst Deactivation
2023 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 66, no 17-18, p. 1310-1328Article in journal (Refereed) Published
Abstract [en]

The conversion of biomass-derived oxygenates over zeolite catalysts constitutes a challenge for the efficient production of bio-based chemicals and fuels due to difficulty in controlling the selectivity and high coke formation of such reactions. This is partly attributed to the microstructure of zeolite catalyst which affects the conversion and selectivity of products derived from biomass-derived oxygenates. In this study, the conversion and deactivation characteristics of three different model oxygenates found in biomass bio-oil (namely, acetol, furfural and guaiacol) over ZSM-5 zeolites of varying acidity, pore and crystal size prepared with bottom-up and top-down approaches were evaluated using a fixed bed microreactor at atmospheric pressure and a space velocity of 5 h−1 at a temperature range of 450–650 °C. Analysis of the experimental results indicates that the optimum temperature for such conversions is in the vicinity of 600 °C allowing for complete conversion of the compounds and high resistance to coking. The mechanisms of those conversions are discussed based on the obtained results. In general, crystal size and mesoporosity induce easier access to active sites improving mass transfer but also alter the location type, and strength of acid sites allowing for higher yields of primary and intermediate products such as olefins.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Acid catalysis, Biomass pyrolysis, Catalytic cracking, Hierarchical HZSM-5, Olefins, Oxygenates
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-338558 (URN)10.1007/s11244-023-01833-4 (DOI)001013088300001 ()2-s2.0-85163212151 (Scopus ID)
Note

QC 20231107

Available from: 2023-11-07 Created: 2023-11-07 Last updated: 2023-11-07Bibliographically approved
Pach, M., Hittig, H., Scholle, T., Kusar, H. & Engvall, K. (2023). Development of a Laboratory Unit to Study Internal Injector Deposits Formation. In: 16th International Conference on Engines and Vehicles, ICE 2023: . Paper presented at SAE 16th International Conference on Engines and Vehicles, ICE 2023, Capri, Italy, Sep 10 2023 - Sep 14 2023. SAE International
Open this publication in new window or tab >>Development of a Laboratory Unit to Study Internal Injector Deposits Formation
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2023 (English)In: 16th International Conference on Engines and Vehicles, ICE 2023, SAE International , 2023Conference paper, Published paper (Refereed)
Abstract [en]

The formation of deposits in the fuel systems of heavy-duty engines, using drop-in fuels, has been reported in recent years. Drop-in fuels are of interest because they allow higher levels of alternative fuels to be blended with conventional fuels that are compatible with today's engines. The precipitation of insolubles in the drop-in fuel can lead to clogging of fuel filters and internal injector deposits, resulting in increased fuel consumption and engine drivability problems. The possible mechanisms for the formation of the deposits in the fuel system are not yet fully understood. Several explanations such as operating conditions, fuel quality and contamination have been reported. To investigate injector deposit formation, several screening laboratory test methods have been developed to avoid the use of more costly and complex engine testing. To further evaluate and understand the formation of internal injector deposits in heavy-duty engines, a thermal laboratory test method has been developed. The test method is called Thermal Deposits Test (TDT) and it is inspired by Jet Fuel Thermal Oxidation Test (JFTOT) method. This test unit can be used to study in applications where a fluid is in contact with a hot surface. The method uses common laboratory hardware and readily available off-the-shelf parts, making it inexpensive to build and very flexible to operate. Deposits are collected on a metal foil, which makes it easier to analyze. This paper describes the construction of the apparatus and its performance. Experimental tests with diesel fuel, doped with soap-type soft particles, which contain typical particles that can form deposits, are performed, and compared with JFTOT results. Analytical techniques, such as Scanning Electron Microscopy with Energy Dispersive X-Ray, Fourier-transform Infrared Spectroscopy, and Pyrolysis coupled with Gas Chromatography-Mass Spectroscopy and Ellipsometry were used. Conclusions about the performance of the doped fuel are drawn from the test. Future plans are to study the mechanisms behind the formation of internal diesel injector deposits.

Place, publisher, year, edition, pages
SAE International, 2023
National Category
Energy Engineering Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-338989 (URN)10.4271/2023-24-0078 (DOI)2-s2.0-85174000099 (Scopus ID)
Conference
SAE 16th International Conference on Engines and Vehicles, ICE 2023, Capri, Italy, Sep 10 2023 - Sep 14 2023
Note

QC 20231101

Available from: 2023-11-01 Created: 2023-11-01 Last updated: 2023-11-01Bibliographically approved
Zhou, C., Rosén, C. & Engvall, K. (2023). Early Detection of Bed Defluidization in Steam-Oxygen Biomass-Pressurized Fluidized Bed Gasifiers. Industrial & Engineering Chemistry Research, 63(1), 672-690
Open this publication in new window or tab >>Early Detection of Bed Defluidization in Steam-Oxygen Biomass-Pressurized Fluidized Bed Gasifiers
2023 (English)In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 63, no 1, p. 672-690Article in journal (Refereed) Published
Abstract [en]

In the present study, an improved understanding of dynamic temperature and differential pressure phenomena during pressurized biomass gasification in a bubbling fluidized bed is used to develop a method for the early detection of bed defluidization. Experiments with silica sand as a bed material and three different biomass feedstocks, namely, birch chips, grot chips, and pine pellets, were conducted. For comparison, experiments using magnesite and dolomite as the bed materials were also conducted. The main variables potentially influencing bed fluidization, including K content and K/Si ratio in fuel feedstock, bed temperature, steam, and fluidization velocity, were considered in relation to their effect on bed defluidization time. Correlation of differential pressure and temperature at different positions in the bed with fluidized bed changes, such as char accumulation, sticky coating formation on particles, and char consumption, was evaluated and identified. The study demonstrates that under the operating conditions investigated, it is possible to determine the bed defluidization tendency fairly accurately using a combination of bed temperature deviation and the deviation of two series of dynamic differential pressure signals, measured at different bed positions.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-343057 (URN)10.1021/acs.iecr.3c03117 (DOI)001140898300001 ()2-s2.0-85181581662 (Scopus ID)
Note

QC 20240206

Available from: 2024-02-06 Created: 2024-02-06 Last updated: 2024-02-06Bibliographically approved
Hohmann, L., Marks, K., Chien, T.-E., Ostrom, H., Hansson, T., Muntwiler, M., . . . Harding, D. J. (2023). Effect of Coadsorbed Sulfur on the Dehydrogenation of Naphthalene on Ni(111). The Journal of Physical Chemistry C, 128(1), 67-76
Open this publication in new window or tab >>Effect of Coadsorbed Sulfur on the Dehydrogenation of Naphthalene on Ni(111)
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2023 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 128, no 1, p. 67-76Article in journal (Refereed) Published
Abstract [en]

There are several difficulties when experimentally determined reaction mechanisms are applied from model systems to real catalysis. Besides the infamous pressure and material gaps, it is sometimes necessary to consider impurities in the real reactant feedstock that can act as promoters or catalyst poisons and alter the reaction path. In this study, the effect of sulfur on the dehydrogenation of naphthalene on Ni(111) is investigated by using X-ray photoelectron spectroscopy and scanning tunneling microscopy. Sulfur induces a (5 root 3 x 2) surface reconstruction, as previously reported in the literature. The sulfur does not have a strong effect on the dehydrogenation temperature of naphthalene. However, the presence of sulfur leads to a preferred formation of carbidic over graphitic carbon and a strong inhibition of carbon diffusion into the nickel bulk, which is one of the steps of destructive whisker carbon formation described in the catalysis literature.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-342729 (URN)10.1021/acs.jpcc.3c04475 (DOI)001141749800001 ()2-s2.0-85180944787 (Scopus ID)
Note

QC 20240216

Available from: 2024-02-16 Created: 2024-02-16 Last updated: 2024-02-16Bibliographically approved
Ge, Y., Ding, S., Zhang, W., Kong, X., Engvall, K. & Pettersson, J. B. C. (2023). Effect of fresh bed materials on alkali release and thermogravimetric behavior during straw gasification. Fuel, 336, Article ID 127143.
Open this publication in new window or tab >>Effect of fresh bed materials on alkali release and thermogravimetric behavior during straw gasification
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2023 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 336, article id 127143Article in journal (Refereed) Published
Abstract [en]

Alkali-associated problems are key issues for the efficient use of straw that is available as a major renewable energy resource worldwide. The effects of six bed materials commonly used in fluidized bed reactors on straw pyrolysis and char gasification were evaluated using online monitoring of alkali release and thermogravimetric analysis. Scanning electron microscopy with energy dispersive spectroscopy was used to determine the elemental composition of the char surface. In the straw pyrolysis stage, alkali release is reduced by the addition of dolomite and silica due to alkali adsorption on the bed materials, and enhanced by the addition of alumina because of its high sodium content. In the char gasification stage, silica, sea sand, olivine, and ilmenite reduce the char reactivity and alkali release, which is attributed to transfer of Si and Ti from the bed materials to the char and reaction with alkali to form stable and catalytically inactive compounds. Alumina also reduces the char conversion rate by transfer of Al to the char and formation of K-Al-Si and Ca-Al-Si compounds, while alkali release from the straw and alumina blend remains high due to the high Na content in alumina. Dolomite initially appears to increase the char gasification reactivity, but the results are affected by conversion of volatile matter that deposited on the dolomite in the straw pyrolysis stage. Dolomite also significantly increases the alkali release, which is attributed to Ca reactions with aluminosilicate compounds that allow potassium to remain in volatile form. Fresh bed materials are concluded to have significant effects on straw conversion depending on their chemical composition, and the results can contribute to the understanding required for efficient use of straw in commercial applications of biomass thermochemical conversion.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Alkali, Straw, Bed material, Gasification, Pyrolysis, Surface ionization detector
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-323232 (URN)10.1016/j.fuel.2022.127143 (DOI)000906234800001 ()2-s2.0-85144039987 (Scopus ID)
Note

QC 20230124

Available from: 2023-01-24 Created: 2023-01-24 Last updated: 2023-01-24Bibliographically approved
Li, F., Chang, F., Lundgren, J., Zhang, X., Liu, Y., Engvall, K. & Ji, X. (2023). Energy, Cost, and Environmental Assessments of Methanol Production via Electrochemical Reduction of CO2 from Biosyngas. ACS Sustainable Chemistry and Engineering, 11(7), 2810-2818
Open this publication in new window or tab >>Energy, Cost, and Environmental Assessments of Methanol Production via Electrochemical Reduction of CO2 from Biosyngas
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2023 (English)In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 11, no 7, p. 2810-2818Article in journal (Refereed) Published
Abstract [en]

Electrochemical reduction of CO2 removed from biosyngas into value-added methanol (CH3OH) provides an attractive way to mitigate climate change, realize CO2 utilization, and improve the overall process efficiency of biomass gasification. However, the economic and environmental feasibilities of this technology are still unclear. In this work, economic and environmental assessments for the stand-alone CO2 electrochemical reduction (CO2R) toward CH3OH with ionic liquid as the electrolyte and the integrated process that combined CO2R with biomass gasification were conducted systematically to identify key economic drivers and provide technological indexes to be competitive. The results demonstrated that costs of investment associated with CO2R and electricity are the main contributors to the total production cost (TPC). Integration of CO2R with CO2 capture/purification and biomass gasification could decrease TPC by 28%-66% under the current and future conditions, highlighting the importance of process integration. Energy and environmental assessment revealed that the energy for CO2R dominated the main energy usage and CO2 emissions, and additionally, the energy structure has a great influence on environmental feasibility. All scenarios could provide climate benefits over the conventional coal-to-CH3OH process if renewable sources are used for electricity generation.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
Keywords
carbon dioxide, economic analysis, Electrochemical reduction, energy, environmental assessment, methanol production
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-330017 (URN)10.1021/acssuschemeng.2c05968 (DOI)000929071000001 ()2-s2.0-85147820420 (Scopus ID)
Note

QC 20230629

Available from: 2023-06-29 Created: 2023-06-29 Last updated: 2023-09-21Bibliographically approved
Ge, Y., Ding, S., Zhang, W., Kong, X., Kantarelis, E., Engvall, K. & Pettersson, J. B. .. (2023). Impacts of fresh bed materials on alkali release and fuel conversion rate during wood pyrolysis and char gasification. Fuel, 353, Article ID 129161.
Open this publication in new window or tab >>Impacts of fresh bed materials on alkali release and fuel conversion rate during wood pyrolysis and char gasification
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2023 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 353, article id 129161Article in journal (Refereed) Published
Abstract [en]

Bed materials provide efficient heat transfer and catalytic function in the thermochemical conversion of biomass, but their interactions with the fuel remain incompletely understood. In this study, the effects of bed materials on alkali release and fuel conversion during wood pyrolysis and CO2 gasification are investigated by online alkali detection combined with thermogravimetric analysis. The investigated bed materials include silica, sea sand, alumina and the natural ores olivine, ilmenite and dolomite. Only dolomite has a significant effect on fuel mass loss and alkali release during wood pyrolysis, while all bed materials influence char reactivity and alkali release during gasification. Sea sand, alumina and dolomite enhance the char gasification during the whole or most of the gasification process, which is related to alkali migration from the bed materials. All bed materials affect char reactivity and alkali release when the conversion approaches completion, and small amounts of some bed materials reduce the alkali release by an order of magnitude. The findings can be understood based on the chemical composition of the different materials. Silicon-rich materials reduce the levels of catalytically active alkali by formation of stable alkali silicates, and a similar explanation applies for ilmenite that captures alkali efficiently. Magnesium and calcium in contrast promote alkali release through their influence on alkali silicate chemistry. Analysis of char surfaces using scanning electron microscopy with energy dispersive spectroscopy indicates that low amounts of several elements are transferred from the bed material to the char where they may be directly involved in the char conversion process. The transferred elements are specific for each bed material and relates to their chemical composition. Mechanisms for material exchange between bed material and char are discussed.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Alkali, Bed material, Gasification, Pyrolysis, Surface ionization detector, Wood
National Category
Chemical Process Engineering Energy Engineering Bioenergy
Identifiers
urn:nbn:se:kth:diva-334346 (URN)10.1016/j.fuel.2023.129161 (DOI)001047023900001 ()2-s2.0-85165012846 (Scopus ID)
Note

QC 20230821

Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-09-01Bibliographically approved
Ge, Y., Ding, S., Kong, X., Kantarelis, E., Engvall, K. & Pettersson, J. B. .. (2023). Online monitoring of alkali release during co-pyrolysis/gasification of forest and agricultural waste: Element migration and synergistic effects. Biomass and Bioenergy, 172, 106745-106745, Article ID 106745.
Open this publication in new window or tab >>Online monitoring of alkali release during co-pyrolysis/gasification of forest and agricultural waste: Element migration and synergistic effects
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2023 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 172, p. 106745-106745, article id 106745Article in journal (Refereed) Published
Abstract [en]

Fuel blends may be used to meet several operational needs in thermal conversion of biomass waste, including optimization of ash properties and fuel conversion efficiency. In this study, online alkali measurements using surface ionization are employed to study synergistic effects produced by inorganic elements during co-pyrolysis/gasification of wood and straw waste. Synergistic effects on the fuel conversion behavior are not observed during co-pyrolysis, while alkali migration from straw to wood is clearly observed above 600 °C by online alkali monitoring. In contrast, synergistic effects on char conversion and alkali release are substantial during co-gasification. Positive effects on char reactivity during most of the gasification process are attributed to alkali migration from the straw to the wood char, and the most pronounced effect occurs at a gasification temperature of 900 °C and a straw content of 25%. Negative effects on char reactivity are observed at the final gasification stage, which is associated with a significantly reduced alkali release from fuel blends compared to pure wood char. The effect is attributed to the migration of silicon, phosphorus, and aluminum to the wood char, as revealed by scanning electron microscopy with energy dispersive spectroscopy, where the elements react with alkali to form catalytically inactive compounds. The mixing of biofuels is concluded to result in substantial effects on the fuel conversion efficiency, which should be taken into consideration in thermochemical conversion of biomass.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Co-pyrolysis, Co-gasification, Wood, Straw, Alkali, Synergistic effects
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-325670 (URN)10.1016/j.biombioe.2023.106745 (DOI)000951374300001 ()2-s2.0-85149481547 (Scopus ID)
Note

QC 20230412

Available from: 2023-04-11 Created: 2023-04-11 Last updated: 2023-04-25Bibliographically approved
Ding, S., Kantarelis, E. & Engvall, K. (2023). Potassium-Induced Phenomena and Their Effects on the Intrinsic Reactivity of Biomass-Derived Char during Steam Gasification. ACS Omega, 8(32), 29131-29142
Open this publication in new window or tab >>Potassium-Induced Phenomena and Their Effects on the Intrinsic Reactivity of Biomass-Derived Char during Steam Gasification
2023 (English)In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 32, p. 29131-29142Article in journal (Refereed) Published
Abstract [en]

The mineral content of biomass plays an important role in the gasification rate of biomass-derived char. The understanding and quantification of mineral-related phenomena are thus of importance when considering gasification reactor design. In the present work, the potassium-induced catalytic phenomena during gasification of biomass-derived char have been studied. Char samples with similar structure and different intrinsic potassium content were gasified in a steam atmosphere at a temperature range of 700-800 °C. It was found that for all the samples, irrespective of the temperature and the initial potassium content, there is a critical K/C ratio (5 × 10-3), whereafter the catalytic phenomena prevail. The instantaneous conversion rate of the char is positively correlated with the potassium content and the progressively increasing conversion. The application of the modified random pore model was able to capture the later stages of conversion by the introduction of two additional parameters (c and p). It was found that these constants are not just fitting parameters but that there is an underlying physical significance with c being directly related to the intrinsic potassium content while being temperature independent and with p being temperature dependent.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Energy Engineering Chemical Process Engineering Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-338506 (URN)10.1021/acsomega.3c02234 (DOI)001041068900001 ()37599968 (PubMedID)2-s2.0-85167875804 (Scopus ID)
Note

QC 20231103

Available from: 2023-11-03 Created: 2023-11-03 Last updated: 2023-11-03Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-6326-4084

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