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Priestley, M., Kong, X., Pei, X., Pathak, R. K., Davidsson, K., Pettersson, J. B. C. & Hallquist, M. (2023). Volatility Measurements of Oxygenated Volatile Organics from Fresh and Aged Residential Wood Burning Emissions. ACS Earth and Space Chemistry
Open this publication in new window or tab >>Volatility Measurements of Oxygenated Volatile Organics from Fresh and Aged Residential Wood Burning Emissions
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2023 (English)In: ACS Earth and Space Chemistry, E-ISSN 2472-3452Article in journal (Refereed) Epub ahead of print
Abstract [en]

Residential wood combustion (RWC) is a dominant source of anthropogenic aerosol in urban areas. Complexities in aerosol chemical composition, semivolatile behavior, and secondary processing make estimating RWC impacts on climate and air quality challenging. A chemical ionization mass spectrometer with a filter inlet for gas and aerosols measured the gas-to-particle partitioning of organic compounds emitted from log wood and pellet burning stoves. Emissions were aged in an oxidation flow reactor to assess changes in the volatilities of the secondary aerosol. Effective saturation vapor concentrations (C*) of the measured species were derived using both the measured particle-to-gas concentration ratio (Pi/Gi) and vapor pressure measurements (pi0) calibrated using the maximum temperature during evaporation. These were used to derive new molecular formula (MF) parameterizations and were compared to selected previous parameterization. The fresh wood stove emissions were less volatile than those of the pellet stove (particle fractions of 0.96 vs 0.69), likely caused by poorer combustion conditions, producing a greater particle sink for organic vapors. After aging, the volatility of the emissions remained broadly similar, whereas all MF parameterizations showed increasing volatility. This was likely due to the measurement techniques capturing nonideal effects of partitioning that MF parameterizations cannot.

Place, publisher, year, edition, pages
American Chemical Society, 2023
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:ri:diva-71408 (URN)10.1021/acsearthspacechem.3c00066 (DOI)2-s2.0-85182585667 (Scopus ID)
Note

This work was supported by Energimyndigheten (Swedish Energy Agency) project no. 44702-1, the Swedish Research Council (Grant 2018-04430), Formas (Grant 2019-00586), and VR project no. 2015-04123. X.K. acknowledges support from the Swedish Foundation for International Cooperation in Research and Higher Education (CH2019-8361).

Available from: 2024-01-25 Created: 2024-01-25 Last updated: 2024-01-25Bibliographically approved
Råberg, T., Lorentzon, K., Västerdal, M., Pettersson Skog, A., Cristescu, C., Davidsson, K., . . . Atongka Tchoffor, P. (2022). Potentiella kolsänkor i Malmö stad.
Open this publication in new window or tab >>Potentiella kolsänkor i Malmö stad
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2022 (Swedish)Report (Other academic)
Abstract [sv]

Miljöförvaltningen inom Malmö stad gav RISE uppdraget att identifiera möjligheter att öka kolsänkorna inom kommungränsen. Syftet med den här rapporten är att sammanställa ett brett underlag för klimatarbete med åtgärder som möjliggör en ökning av de lokala kolsänkorna i Malmö stads geografiska område. Genom att uppskatta olika åtgärders potential för kolinlagring, teknisk mognadsgrad och kostnadseffektivitet från ett klimatperspektiv, samt visa på vilka skalor det går att jobba med dessa åtgärder inom kommunen, avses rapporteringen ge en översikt över vilka satsningar som kan göras för att kolsänkorna ska kunna bidra till Malmö stads miljö- och klimatmål. Forskargruppen från RISE har analyserat 18 olika kategorier som har potential att öka den lokala kolinlagringen inom: • de urbana grönområdena, • den urbana infrastrukturen, bebyggd mark och tillhörande mark • rural markanvändning och • övriga möjligheter. I beräkningarna ingår inte klimatpåverkan från insatser som krävs för att genomföra åtgärderna, till exempel avverkning, uppdrivning och plantering av skogsplantor, transport av timmer och förädling av virke. I rapporten tas inte hänsyn till om en ökad användning av mark i en kategori, minskar markanvändning inom en annan kategori.

Publisher
p. 63
National Category
Biological Sciences
Identifiers
urn:nbn:se:ri:diva-59992 (URN)
Available from: 2022-08-22 Created: 2022-08-22 Last updated: 2023-10-31Bibliographically approved
Pushp, M., Brackmann, C. & Davidsson, K. (2021). Infrared Spectroscopy for Online Measurement of Tars, Water, and Permanent Gases in Biomass Gasification. Applied Spectroscopy, 75(6), 690-697
Open this publication in new window or tab >>Infrared Spectroscopy for Online Measurement of Tars, Water, and Permanent Gases in Biomass Gasification
2021 (English)In: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 75, no 6, p. 690-697Article in journal (Refereed) Published
Abstract [en]

Online measurements of the raw gas composition, including tars and water, during biomass gasification provide valuable information in fundamental investigations and for process control. Mainly consisting of hydrocarbons, tars can, in principle, be measured using Fourier transform infrared (FT-IR) spectroscopy. However, an instrument subjected to raw gas runs the risk of condensation of tars on optical components and subsequent malfunction. Therefore, an external cell, heated to at least 400 ℃, has been designed to ensure that tars remain in the gas phase during FT-IR measurements. The cell was used for on-line FT-IR measurements of permanent gases (CO, CO2, CH4), water, and tars during the operation of a lab-scale downdraft gasifier using wood pellets, bark pellets, and char chips. Based on calibration, the measurement error of permanent gases was estimated to be 0.2%. Concentrations evaluated from spectral signatures of hydrocarbons in tar are in good agreement with results from solid-phase adsorption measurements and correlated well with operational changes in the gasifier. 

Place, publisher, year, edition, pages
SAGE Publications Inc., 2021
Keywords
gasification, hydrocarbons, infrared spectroscopy, On-line tars, Fourier transform infrared spectroscopy, Infrared imaging, Pelletizing, Biomass Gasification, Downdraft gasifier, Fourier transform infra red (FTIR) spectroscopy, On-line measurement, Operational changes, Risk of condensation, Solid phase adsorptions, Spectral signature, Gases
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-52553 (URN)10.1177/0003702821991891 (DOI)2-s2.0-85101132274 (Scopus ID)
Available from: 2021-03-08 Created: 2021-03-08 Last updated: 2023-05-26Bibliographically approved
Kong, X., Salvador, C., Carlsson, S., Pathak, R., Davidsson, K., Le Breton, M., . . . Pettersson, J. (2021). Molecular characterization and optical properties of primary emissions from a residential wood burning boiler. Science of the Total Environment, 754, Article ID 142143.
Open this publication in new window or tab >>Molecular characterization and optical properties of primary emissions from a residential wood burning boiler
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2021 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 754, article id 142143Article in journal (Refereed) Published
Abstract [en]

Modern small-scale biomass burners have been recognized as an important renewable energy source because of the economic and environmental advantages of biomass over fossil fuels. However, the characteristics of their gas and particulate emissions remain incompletely understood, and there is substantial uncertainty concerning their health and climate impacts. Here, we present online measurements conducted during the operation of a residential wood-burning boiler. The measured parameters include gas and particle concentrations, optical absorption and chemical characteristics of gases and particles. Positive matrix factorization was performed to analyze data from a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) equipped with a filter inlet for gases and aerosols (FIGAERO). Six factors were identified and interpreted. Three factors were related to the chemical composition of the fuel representing lignin pyrolysis products, cellulose/hemicellulose pyrolysis products, and nitrogen-containing organics, while three factor were related to the physical characteristics of the emitted compounds: volatile compounds, semi-volatile compounds, and filter-derived compounds. An ordinal analysis was performed based on the factor fractions to identify the most influential masses in each factor, and by deconvoluting high-resolution mass spectra fingerprint molecules for each factor were identified. Results from the factor analysis were linked to the optical properties of the emissions, and lignin and cellulose/hemicellulose pyrolysis products appeared to be the most important sources of brown carbon under the tested burning conditions. It is concluded that the emissions from the complex combustion process can be described by a limited set of physically meaningful factors, which will help to rationalize subsequent transformation and tracing of emissions in the atmosphere and associated impacts on health and climate. 

Place, publisher, year, edition, pages
Elsevier B.V., 2021
Keywords
Brown carbon, Cellulose, CIMS, Lignin, Positive matrix factorization, Boilers, Chemical analysis, Factor analysis, Factorization, Fossil fuels, Gas emissions, Housing, Ionization of gases, Light absorption, Mass spectrometers, Mass spectrometry, Pyrolysis, Renewable energy resources, Volatile organic compounds, Chemical characteristic, High-resolution mass spectrum, Molecular characterization, Particle concentrations, Physical characteristics, Renewable energy source, Residential wood burning, Optical properties, Analysis Of Variance
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-48764 (URN)10.1016/j.scitotenv.2020.142143 (DOI)2-s2.0-85090186936 (Scopus ID)
Note

Funding details: Energimyndigheten, 44702-1; Funding details: Svenska ForskningsrÃ¥det Formas; Funding text 1: This work was supported by the Swedish Energy Agency ( 44702-1 ). ÅMH acknowledge support from Formas ( 214-2013-1430 ). We gratefully thank Ingmar Schuessler for help with operating the boiler.

Available from: 2020-09-14 Created: 2020-09-14 Last updated: 2023-05-23Bibliographically approved
Janhäll, S., Petersson, M., Davidsson, K., Öman, T., Sommertune, J., Kåredal, M., . . . Rissler, J. (2021). Release of carbon nanotubes during combustion of polymer nanocomposites in a pilot-scale facility for waste incineration. NanoImpact, 24, Article ID 100357.
Open this publication in new window or tab >>Release of carbon nanotubes during combustion of polymer nanocomposites in a pilot-scale facility for waste incineration
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2021 (English)In: NanoImpact, ISSN 2452-0748, Vol. 24, article id 100357Article in journal (Refereed) Published
Abstract [en]

Nanocomposites, formed by incorporating nanoparticles into a matrix of standard materials, are increasing on the market. Little focus has been directed towards safe disposal and recycling of these new materials even though the disposal has been identified as a phase of the products' life cycle with a high risk of uncontrolled emissions of nanomaterials. In this study, we investigate if the carbon nanotubes (CNTs), when used as a filler in two types of polymers, are fully destructed in a pilot-scale combustion unit designed to mimic the combustion under waste incineration. The two polymer nanocomposites studied, polycarbonate (PC) with CNT and high-density polyethylene (HDPE) with CNT, were incinerated at two temperatures where the lower temperature just about fulfilled the European waste incineration directive while the upper was chosen to be on the safe side of fulfilling the directive. Particles in the flue gas were sampled and analysed with online and offline instrumentation along with samples of the bottom ash. CNTs could be identified in the flue gas in all experiments, although present to a greater extent when the CNTs were introduced in PC as compared to in HDPE. In the case of using PC as polymer matrix, CNTs were identified in 3–10% of the analysed SEM images while for HDPE in only ~0.5% of the images. In the case of PC, the presence of CNTs decreased with increasing bed temperature (from 10% to 3% of the images). The CNTs identified were always in bundles, often coated with remnants of the polymer, forming particles of ~1–4 μm in diameter. No CNTs were identified in the bottom ash, likely explained by the difference in time when the bottom ash and fly ash are exposed to high temperatures (~hours compared to seconds) in the pilot facility. The results suggest that the residence time of the fly ash in the combustion zone is not long enough to allow full oxidation of the CNTs. Thus, the current regulation on waste incineration (requiring a residence time of the flue gas >850 °C during at least 2 s) may not be enough to obtain complete destruction of CNTs in polymer composites. Since several types of CNTs are known to be toxic, we stress the need for further investigation of the fate and toxicity of CNTs in waste treatment processes.

Keywords
Waste incineration, Polymer, CNT, Particle, Fly ash, Nanocomposites
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-58176 (URN)10.1016/j.impact.2021.100357 (DOI)
Available from: 2022-01-14 Created: 2022-01-14 Last updated: 2023-06-07Bibliographically approved
Dahlbom, S., Davidsson, K., Johansson, I., Jonasson, A., Vatten RUI, M. H., Sjöblom, R. & Östrem, S. (2020). Minimering av vätgasrelaterade risker från avfallseldade CFB-pannor. Energiforsk
Open this publication in new window or tab >>Minimering av vätgasrelaterade risker från avfallseldade CFB-pannor
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2020 (Swedish)Report (Other academic)
Abstract [sv]

Det finns driftparametrar som påverkar reaktiviteten på flygaskan från avfallseldade CFB-pannor. Det finns också goda skäl att tänka ett par varv extra kring säkerhetsfrågor i miljöer där dessa askor kommer i kontakt med, eller har kommit i kontakt med, vatten! Det är tidigare känt att askor från avfallseldade CFB-pannor kan bilda vätgas när de kommer i kontakt med vatten. Det övergripande syftet med projektet har varit att minska de vätgasrelaterade arbetsmiljöriskerna förknippade med dessa flygaskor samt att öka kunskapsnivån kring de vätgasrelaterade riskerna generellt. Projektet har undersökt vilka driftparametrar och mekanismer som kan påverka vätgasbildningen både sett till mängd och hastighet, undersökt mängden metalliskt aluminium i askor/beläggningar i pannan samt att genomfört en grovriskanalys för en tänkt logistikkedja med båt. Undersökningarna har fokuserats till P14 och P15 vid E.ON:s Händelöverk. Resultaten visade bland annat att det i litteraturen finns väldigt lite information direkt relaterad till frågeställningen i CFB-pannor. Istället får slutsatser och teorier byggas kring litteratur som hanterar närliggande frågeställningar i andra miljöer. De experimentella resultaten indikerar att det finns en skillnad i reaktivitet i flygaskan mellan de båda pannorna och att val av bäddmaterial är en driftparameter som tycks kunna påverka reaktiviteten. Vid inblandning av ilmenit i bäddmaterialet tycktes den maximala vätgasbildningen sjunka och/eller bli mer fördröjd i tiden. De övriga driftfall som studerades var: dellast, varierande tillsats av ammoniak i SNCR systemet samt lagring/åldring av aska i NID-filtret (rökgasreningen) när en del av filtret är ur drift. Det finns indikationer på att dessa driftfall också kan ha påverkan, men dataunderlaget är för litet för att med säkerhet fastslå något. Det tycks dock svårt att förutom med bäddmaterial påverka reaktiviteten med bibehållen funktion i driften i övrigt. Ask/beläggningsprover från olika delar av pannorna visade att halten metalliskt aluminium i ekonomiser är fullt jämförbar med de efter NID-filtret och därmed är det stor risk för vätgasbildning vid våt rengöring av dessa delar. God ventilation och utbildningsinsatser för att öka medvetenheten är viktiga rekommendationer för att minska/hantera risken. Slutsatserna från grovriskanalysen logistikkedjan lyfter faran med att generalisera vätgasbildningen från askorna eftersom den varierar så kraftigt. Det är också viktigt att ta hänsyn till att vätgasbildningen kan vara fördröjd och inte initieras förrän askan utsätts för mekanisk bearbetning. Den mekaniska bearbetningen utgör också en risk utifrån att den kan initiera gnistbildning. Denna gnistbildning kan i sin tur agera som tändkälla för bildad gas.

Abstract [en]

There are operating parameters that affect the hydrogen formation from APC-residues generated in waste fired CFB-boilers. There are also reasons to be careful and take extra consideration to safety aspects in environments where the APC-residue has been exposed to water. It is well known that if the APC-residues generated from waste fired CFB-boilers are exposed to water; hydrogen gas is formed. The overall aim of the project has been to decrease the work environment hazards related to hydrogen formation from these APC-residues. Another aim has also been to increase the general knowledge related to these hydrogen related hazards. This has been accomplished by exploring which operating parameters and general mechanisms that affect the hydrogen formation from the APC-residues. Both total amount of gas formed as well as the velocity of the gas formation has been of interest. The APC-residues used in this project have been from P14 and P15 at the waste-to-energy plant Händelöverket, owned and operated by E.ON. In literature there are almost no publications on the hydrogen gas formation from APC residues generated by waste fired CFB boilers. There are some related to waste fired grate boilers though. Conclusions and theories from literature data must be put together from results regarding similar materials in totally different environments. The experimental results indicate a difference in the hydrogen formation from APCresidues originating from P14 and P15. The bed material used in the boilers is also one of the operational parameters that seems to affect the reactivity of the APCresidue. The introduction of a share of Ilmenite in the bed material seems to have lowered the amount of hydrogen gas formed, alternatively it delayed the formation. Other operational conditions that was considered was a decreased thermal load, lowered amount of ammonia added to reduce NOx, and storage/aging of ash in the NID-reactor while it was not running on full capacity. There are indications that these conditions also affect the reactivity, however there are too few data available to make specific conclusions. In general, it seems difficult to control the reactivity of the APC-residue while keeping normal production in the plant. In fouling samples, from different parts of the boilers, levels of metallic aluminium fully comparable to those in the APC-residue were detected. Thus, there is a significant risk of hydrogen formation when using wet cleaning methods during maintenance stops. Proper ventilation and education are two of the recommendations to mitigate the risks. A potential logistic chain for APC-residues, based on ship transports, was risk assessed. Since the hydrogen formation differs greatly between different ash deliveries, an important conclusion was that it is hazardous to generalise the results, especially by using average hydrogen formation rates. Another conclusion was that consideration must be made for the fact that the hydrogen formation might be delayed and might not arise until the APC-residue is treated mechanically

Place, publisher, year, edition, pages
Energiforsk, 2020. p. 98
Series
Energiforsk rapport 2020:719
National Category
Energy Engineering
Identifiers
urn:nbn:se:ri:diva-64367 (URN)978-91-7673-719-4 (ISBN)
Note

Här redovisas resultat och slutsatser från ett projekt inom ett forskningsprogram som drivs av Energiforsk.

Available from: 2023-04-20 Created: 2023-04-20 Last updated: 2023-06-08Bibliographically approved
Lundberg, L., Atongka Tchoffor, P., Pallarès, D., Thunman, H. & Davidsson, K. (2019). Impacts of Bed Material Activation and Fuel Moisture Content on the Gasification Rate of Biomass Char in a Fluidized Bed. Industrial & Engineering Chemistry Research, 58(12), 4802-4809
Open this publication in new window or tab >>Impacts of Bed Material Activation and Fuel Moisture Content on the Gasification Rate of Biomass Char in a Fluidized Bed
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2019 (English)In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 58, no 12, p. 4802-4809Article in journal (Refereed) Published
Abstract [en]

The use of certain bed materials has been found to increase the steam gasification rate of biomass char. The present work investigates how this phenomenon is influenced by different parameters (e.g., temperature, fuel type, and fuel moisture content), using a laboratory-scale bubbling fluidized bed gasifier. Silica sand, fresh olivine, and activated olivine were employed as bed materials, and three biomass fuels (wood chips, wood pellets, and forest residue pellets) were considered. Switching the bed material from silica sand to activated olivine resulted in a significant increase in the char gasification rate for all three fuels, with further increases noted as the fuel particle size was decreased. The observed effect was strongest (up to 4-fold) during the initial conversion phase (char gasification degrees < 20%) when the temperature was relatively low (≤ 800 °C). The moisture content of the wood chips (0-40%) had no significant effect on the char gasification rate.

Place, publisher, year, edition, pages
American Chemical Society, 2019
Keywords
Biomass, Fuels, Gasification, Moisture, Moisture determination, Olivine, Particle size, Pelletizing, Silica, Silica sand, Silicate minerals, Wood fuels, Wood products, Bed materials, Biomass fuels, Bubbling fluidized bed, Char gasification, Forest residue, Fuel moisture content, Fuel particles, Steam gasification, Fluidized beds
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38344 (URN)10.1021/acs.iecr.9b00528 (DOI)2-s2.0-85063607080 (Scopus ID)
Available from: 2019-05-06 Created: 2019-05-06 Last updated: 2023-06-07Bibliographically approved
Lönnermark, A., Persson, H., Hedenstedt, A., Jones, F., Davidsson, K., Johansson, I. & Boström, S. (2019). Rekommendation för proaktivt brandskyddsarbete. Malmö: Avfall sverige
Open this publication in new window or tab >>Rekommendation för proaktivt brandskyddsarbete
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2019 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Malmö: Avfall sverige, 2019. p. 40
Series
Avfall Sverige, ISSN 1103-4092 ; Rapport 2019:16
Keywords
Rekommendationer; avfall; lagring; rutiner; avfallsanläggningar; brandsäkerhet; släckvatten
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:ri:diva-39950 (URN)
Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2023-05-23Bibliographically approved
Pushp, M., Gall, D., Davidsson, K., Seemann, M. & Pettersson, J. B. (2018). Influence of Bed Material, Additives, and Operational Conditions on Alkali Metal and Tar Concentrations in Fluidized Bed Gasification of Biomass. Energy & Fuels, 32(6), 6797-6806
Open this publication in new window or tab >>Influence of Bed Material, Additives, and Operational Conditions on Alkali Metal and Tar Concentrations in Fluidized Bed Gasification of Biomass
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2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 6, p. 6797-6806Article in journal (Refereed) Published
Abstract [en]

Gasification of biomass results in release of tar and alkali metal compounds that constitute a significant challenge to the optimization of the gasification process. Here we describe on-line measurements of alkali, condensable tar, and particle concentrations in product gas from a 2-4 MWth dual fluidized bed gasifier, with the aims to characterize typical concentrations and contribute to the understanding of alkali-tar interactions. The influence of bed material, additives, and operational parameters on the concentrations is investigated. Alkali concentrations are measured with a surface ionization detector, and particle and tar concentrations are determined using aerosol measurement techniques. The gasification of wood chips using quartz or olivine as bed material results in an alkali concentration of 30-250 mg m-3, and the observed alkali levels are consistent with a significant release of the fuel alkali content. Addition of ilmenite to a quartz bed and additions of K2SO4 and K2CO3 to an olivine bed influence both alkali and heavy tar concentrations. The additions result in changes in alkali concentration that relaxes to a new steady state in tens of minutes. The concentration of condensable tar is lower for the olivine bed than for the quartz bed, and tends to decrease when potassium or sulfur is added. The concentration of condensable tar compounds is anticorrelated with the alkali concentration when a quartz bed is used, while no clear trend is observed with an olivine bed. An increase in steam flow rate results in a substantial decrease in heavy tar concentration from a quartz sand bed, while the alkali concentration increases slightly with increasing flow rate. This is in contrast to the alkali concentrations observed when using an activated olivine bed, where concentrations are higher and tend to decrease with increasing steam flow rate. The study confirms that several primary methods are available to optimize the alkali and tar behavior in the gasifier, and suggests that on-line monitoring is needed to systematically change the operational conditions and to study the underlying processes.

Keywords
Gasification, Ionization of gases, Olivine, Potash, Quartz, Silicate minerals, Tar, Wood products, Aerosol measurement, Alkali concentrations, Fluidized bed gasification, Gasification process, On-line measurement, Operational conditions, Operational parameters, Particle concentrations, Fluidized beds
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34495 (URN)10.1021/acs.energyfuels.8b00159 (DOI)2-s2.0-85046657408 (Scopus ID)
Note

 Funding details: Energimyndigheten; Funding details: Chalmers Tekniska Högskola;

Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2023-05-26Bibliographically approved
Gall, D., Pushp, M., Larsson, A., Davidsson, K. & Pettersson, J. B. C. (2018). Online Measurements of Alkali Metals during Start-up and Operation of an Industrial-Scale Biomass Gasification Plant. Energy & Fuels, 32(1), 532-541
Open this publication in new window or tab >>Online Measurements of Alkali Metals during Start-up and Operation of an Industrial-Scale Biomass Gasification Plant
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2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 1, p. 532-541Article in journal (Refereed) Published
Abstract [en]

Alkali metal compounds may have positive influences on biomass gasification by affecting char reactivity and tar reforming but may also disturb the process by formation of deposits and agglomerates. We herein present results from online measurements of alkali compounds and particle concentrations in a dual fluidized bed gasifier with an input of 32 MWth. A surface ionization detector was used to measure alkali concentrations in the product gas, and aerosol particle measurement techniques were employed to study concentrations and properties of condensable components in the gas. Measurements were performed during start-up and steady-state operation of the gasifier. The alkali concentration increased to approximately 200 mg m-3 when fuel was fed to the gasifier and continued to rise during activation of the olivine bed by addition of potassium carbonate, while the alkali concentration was in the range from 20 to 60 mg m-3 during steady-state operation. Addition of fresh bed material and recirculated ash had noticeable effects on the observed alkali concentrations, and K2CO3 additions to improve tar chemistry resulted in increased levels of alkali in the product gas. Addition of elemental sulfur led to reduced concentrations of CH4 and heavy tars, while no clear influence on the alkali concentration was observed. The study shows that alkali concentrations are high in the product gas, which has implications for the fluidized bed process, tar chemistry, and operation of downstream components including coolers, filters, and catalytically active materials used for product gas reforming.

Keywords
Alkali metal compounds, Fluidized bed process, Fluidized beds, Gases, Ionization of gases, Potash, Silicate minerals, Tar, Aerosol particle measurement, Alkali concentrations, Biomass Gasification, Biomass gasification plant, Condensable components, Downstream components, Particle concentrations, Steady-state operation, Gasification
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33248 (URN)10.1021/acs.energyfuels.7b03135 (DOI)2-s2.0-85040766200 (Scopus ID)
Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2023-05-26Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5998-8058

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