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Häggström, G., Hannl, T. K., Holmgren, P., Broström, M., Skoglund, N. & Öhman, M. (2023). Fate of phosphorus in pulverized fuel co-combustion of sewage sludge and agricultural residues. Fuel, 335, Article ID 127059.
Open this publication in new window or tab >>Fate of phosphorus in pulverized fuel co-combustion of sewage sludge and agricultural residues
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2023 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 335, article id 127059Article in journal (Refereed) Published
Abstract [en]

The fate of phosphorus concerning its distribution in the thermal process and chemical speciation was studied during the co-combustion of sewage sludge with wheat straw and sunflower husks in powder combustion conditions. Co-combustion experiments were performed in a lab-scale entrained flow reactor (EFR) at 1000 °C and 1400 °C. SEM-EDS and ICP-OES analyses were used for studies of deposits collected on a probe, bottom ash, and particulate matter samples collected during experiments. Deposition probe samples were further studied and interpreted using powder X-ray diffraction (XRD) and thermochemical equilibrium calculations (TECs). The inorganic material in the different fuel particles mainly interacted through a molten phase observed on deposition probes. Crystalline P was mainly identified in β-Ca3(PO4)2 whitlockites. TECs support the experimental findings and suggest that a mostly homogenous melt occurs at 1400 °C, whereas Fe-oxides and Ca-phosphates precipitate during the cooling of the formed deposits. It was found that <5 % of incoming P was collected in fine particulate matter (<1 µm), indicating that the majority of P can be found in deposits and bottom ash. This outcome implies that P recovery efforts should be focused on these ash fractions.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Sewage sludge, Phosphorus Combustion, Ash recovery, Powder combustion, Suspension firing
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-90380 (URN)10.1016/j.fuel.2022.127059 (DOI)2-s2.0-85145271125 (Scopus ID)
Funder
Swedish Research Council Formas, 2018-00194; 2017-01613Swedish Research Council, 2017-05331Bio4Energy
Note

Validerad;2023;Nivå 2;2023-02-01 (sofila);

This article has previously appeared as a manuscript in a thesis.

Available from: 2022-04-23 Created: 2022-04-23 Last updated: 2023-09-05Bibliographically approved
Hannl, T. K., Häggström, G., Hedayati, A., Skoglund, N., Kuba, M. & Öhman, M. (2022). Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus. Fuel processing technology, 227, Article ID 107102.
Open this publication in new window or tab >>Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus
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2022 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 227, article id 107102Article in journal (Refereed) Published
Abstract [en]

The recovery of phosphorus (P) from sewage sludge ashes has been the focus of recent research due to the initiatives for the use of biogenic resources and resource recovery. This study investigates the ash transformation chemistry of P in sewage sludge ash during the co-gasification with the K-Si- and K-rich agricultural residues wheat straw and sunflower husks, respectively, at temperatures relevant for fluidized bed technology, namely 800 °C and 950 °C. The residual ash was analyzed by ICP­AES, SEM/EDS, and XRD, and the results were compared to results of thermochemical equilibrium calculations. More than 90% of P and K in the fuels were retained in the residual ash fraction, and significant interaction phenomena occurred between the P-rich sewage sludge and the K-rich ash fractions. Around 45–65% of P was incorporated in crystalline K-bearing phosphates, i.e., K-whitlockite and CaKPO4, in the residual ashes with 85–90 wt% agricultural residue in the fuel mixture. In residual ashes of sewage sludge and mixtures with 60–70 wt% agricultural residue, P was mainly found in Ca(Mg,Fe)-whitlockites and AlPO4. Up to about 40% of P was in amorphous or unidentified phases. The results show that gasification provides a potential for the formation of K-bearing phosphates similar to combustion processes.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Phosphate, Sewage sludge, Wheat straw, Sunflower husk, Thermodynamic equilibrium, Nutrient recovery
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-87965 (URN)10.1016/j.fuproc.2021.107102 (DOI)000750027100003 ()2-s2.0-85119415738 (Scopus ID)
Funder
Swedish Research Council Formas, 2015-619Swedish Research Council, 2016-04380Swedish Research Council, 2017-05331Swedish Research Council Formas, 2017-01613
Note

Validerad;2022;Nivå 2;2022-03-02 (hanlid)

Available from: 2021-11-22 Created: 2021-11-22 Last updated: 2023-10-14Bibliographically approved
Häggström, G. (2022). Studies of ash transformation processes in thermochemical co-conversion of phosphorus-rich manure and sludge with biomass residues. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Studies of ash transformation processes in thermochemical co-conversion of phosphorus-rich manure and sludge with biomass residues
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Efficient use of resources and sustainable recovery of various materials are important to minimize the anthropogenic impact on the climate and environment. One such resource is the phosphorus (P) present in manure and sewage sludge. Various technologies are currently being developed to recover the element for application as fertilizer in agricultural applications. Thermochemical conversion presents the opportunity to recover energy from these materials. In a single process, elements can be recovered in ash fractions, potentially harmful organic substances can be destroyed and heavy metals fractionated from the P. Mono-combustion of sewage sludge mainly produce apatite, a phosphate mineral with low plant availability and therefore less useful for fertilization. Co-combustion/-gasification with other fuels enables modification of the ash transformation reaction pathways and remedies potential problems, such as bed agglomeration, associated with forestry and agricultural residues when used as fuels.

The overall objective of this work was to increase the current knowledge in ash transformation of P-rich materials in co-conversion with forestry and agricultural residues in order to facilitate the P-recovery by formation of suitable phosphates in the ash. The work focuses on i) the influence of co-conversion on ash transformation of P with a focus on altering speciation of P towards the potentially more plant-available K-bearing phosphates ii) the influence of fuel ash composition and chemical association of P in the fuel, temperature and particle interaction on the fate, i.e. speciation and distribution, of P and iii) practical implications of co-conversion in fluidized bed and pulverized fuel systems for P-recovery, specifically interaction of P-rich ash with bed material in fluidized beds and strategies for extracting P-rich ashes.

Experiments were carried out in a bench-scale bubbling fluidized bed reactor (BFB), macro-thermogravimetric analysis (TGA) conversion reactor, a dual fluidized bed (DFB) gasification reactor, and an entrained flow reactor (EFR) for pulverized fuel combustion. The fuels studied were mixtures of chicken litter together with wheat straw and bark, and mixtures of digested sewage sludge combined with wheat straw and sunflower husk. The process temperature ranges studied were 800-950 °C for BFB and single-pellet macro-TGA studies, whereas 1000 °Cand 1400 °C were investigated in pulverized fuel combustion studies using the EFR. Ash fractions and bed materials were collected and analyzed using scanning electron microscopy with energy-dispersive Xray spectroscopy (SEM-EDS), powder X-ray diffraction (XRD), inductively coupled plasma with atomic emission spectroscopy (ICPAES) and ion chromatography (IC). The results were interpreted with the support of thermodynamic equilibrium calculations (TECs) using FactSage software with the GTOX & SGPS databases.

For all investigated conditions and fuel mixtures, the major part of P (> 90 %) was found in coarse ash fractions, suggesting that the recovery potential is highest in these fractions. This also means that P and volatile heavy metals can be separated in different ash fractions. Crystalline P was to a higher degree observed in the form of K-bearing whitlockite structures and CaKPO4 in mixtures containing low amounts of sewage sludge and high amounts of agricultural residues rich in K. K-bearing whitlockites were also found in ash of chicken litter and its mixture with wheat straw, as well as in ash deposits formed in pulverized combustion with a sewage sludge and wheat straw mixture combusted at 1000 °C. In mixtures with higher shares of sewage sludge, crystalline P was mainly found as Fe- and Mg-substituted whitlockites and hydroxyapatite. The reaction pathway of P appears to mainly occur through substitution and addition reactions in the condensed phase. The findings show that it is possible to modify the ash transformation of P towards K-bearing phosphates by co-conversion and that the difference between combustion and gasification is small.

For the mixture of chicken litter and K- and Si-rich wheat straw combusted in BFB, P and Si together with K and Ca formed homogeneous ash particles with large amounts of potentially amorphous content. A similar behavior was observed in sewage sludge and wheat straw mixtures, where P and Si were likely present in a melt that was amorphous after extraction. In addition to these particles, P was also observed in crystalline orthophosphate compounds such as hydroxyapatite, aluminium phosphate, whitlockites and CaKPO4. In the mixture of chicken litter with Ca-rich bark, crystalline P was found in the form of hydroxyapatite. In fuel mixtures with higher amounts of Al with Si, the capture of K in aluminosilicates was higher, making it unavailable to form K-bearing phosphates. Small differences in the fate of P, between organically and inorganically associated P found in the fuels were seen in this work. Lower temperatures (800 °C compared to 950 °C) favored the formation of crystalline K-bearing phosphates in single-pellet combustion of sewage sludge and agricultural residues. In pulverized fuel combustion experiments, more crystalline K-bearing phosphates were found at 1000°C compared to 1400 °C. Fuel ash interaction mainly occurred in condensed phases in ash deposits compared to interactions between particles entrained in the flow.

In fluidized bed experiments, P captured Ca and K in relatively high temperature melting phosphates in the fuel ash, decreasing the interactions of these elements with the bed material and thus decreased the risk for bed agglomeration. Possible extraction strategies involve the separation of coarse ash particles from bed material particles or in heated cyclones, avoiding fine ash fractions known to be rich in volatile heavy metals. Mixtures of coarse ash and bed material can potentially also be used for P-recovery. Co-conversion increases the possibility of utilizing existing boilers for recovery of P and increasing their flexibility to different fuels. The results indicate that a powder combustor operating in slagging mode could be a feasible strategy for P recovery because the interaction potential between the formed individual coarse ash particles increases at the hot wall. Plant growth studies have to be performed to further validate the agricultural value of the produced ashes for direct soil application.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2022
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
sewage sludge, agricultural residues, forest residues, ash transformation, potassium, phosphorus, combustion, gasification, phosphorus recovery
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-90381 (URN)978-91-8048-088-8 (ISBN)978-91-8048-089-5 (ISBN)
Public defence
2022-06-13, E632, Luleå tekniska universitet, Universitetsområdet, Porsön, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2022-04-25 Created: 2022-04-23 Last updated: 2023-09-05Bibliographically approved
Häggström, G., Hannl, T. K., Hedayati, A., Kuba, M., Skoglund, N. & Öhman, M. (2021). Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus. Energy & Fuels, 35(12), 10009-10022
Open this publication in new window or tab >>Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus
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2021 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 35, no 12, p. 10009-10022Article in journal (Refereed) Published
Abstract [en]

Recycling of phosphorus in combination with increased utilization of bioenergy can mitigate material and global warming challenges. In addition, co-combustion of different fuels can alleviate ash-related problems in thermal conversion of biomass. The aim of this study is to investigate the ash transformation reactions of mainly P in co-combustion of P-rich sewage sludge (SS) with K-rich sunflower husks (SH) and K-And Si-rich wheat straw (WS). Single pellets of 4 mixtures (10 and 30 wt % SS in WS and 15 and 40 wt % SS in SH) and pure SS were combusted in an electrically heated furnace at process temperatures relevant for fluidized bed combustion (800 and 950 °C). Collected ash fractions were analyzed by inductively coupled plasma techniques, ion chromatography, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray diffraction. Thermodynamic equilibrium calculations were performed to interpret the results. Over 90% of K and P was found to be captured within the residual ash with 30-70% P in crystalline K-bearing phosphates for mixtures with low amounts of SS (WSS10 and SHS15). The significant share of K and P in the amorphous material could be important for P recovery. For the lower percentage mixtures of SS (WSS10 and SHS15), P in crystalline phases was mainly found in K-whitlockite and CaKPO4. For the higher percentage SS mixtures, most of P was found in whitlockites associated with Fe and Mg, and no crystalline phosphates containing K were detected. For P recovery, co-combustion of the lower SS mixtures is favorable, and they are suggested to be further studied concerning the suitability for plant growth.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2021
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-86298 (URN)10.1021/acs.energyfuels.1c00882 (DOI)000664295600019 ()2-s2.0-85108647447 (Scopus ID)
Funder
Swedish Research Council Formas, 942-2015-619; 2017-01613Swedish Research Council, 2016-04380; 2017-05331
Note

Validerad;2021;Nivå 2;2021-07-07 (beamah)

Available from: 2021-07-07 Created: 2021-07-07 Last updated: 2023-09-05Bibliographically approved
Häggström, G. (2020). Experimental studies of ash transformation processes in thermochemical conversion of P-rich biomass and sludge. (Licentiate dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Experimental studies of ash transformation processes in thermochemical conversion of P-rich biomass and sludge
2020 (English)Licentiate thesis, comprehensive summary (Other academic)
Alternative title[sv]
Experimentella studier av asktransformationsprocesser vid termokemisk omvandling av P-rik biomassa och slam
Abstract [en]

The efficient use of resources and sustainable recovery of various materials are important to minimize the anthropogenic impact on the climate and environment. One such resource is the phosphorus present in manure and sewage sludge. Various technologies are currently being developed to recover the phosphorus for the use of fertilizers in agricultural applications. Thermochemical conversion presents an opportunity to recover energy from these materials. At the same time, elements can be recovered in ash fractions, potentially harmful organic substances can be destroyed and heavy metals fractionated from the P. Mono-combustion of sewage sludge mainly produce apatite, which is not plant available and useful for fertilization. Co-combustion/-gasification with other fuels enables modification of ash transformation pathways and also remedy potential problems, such as bed agglomeration, associated with e.g. agricultural residues used as fuels. This thesis aims to increase the current knowledge in ash transformation of phosphorus-rich materials in cocombustion/-gasification with woody and agricultural fuels in process temperatures relevant for fluidized bed systems. The work focuses on i) possibility for formation of plant-available K-bearing phosphates ii) the effect of fuel ash composition and chemical association of P in the fuel on the distribution and speciation of P and iii) interaction of P-rich ash with bed material in fluidized beds. Experiments were carried out in bench-scale bubbling fluidized bed (BFB), macro-TGA (thermogravimetric analysis) combustion reactors and a dual fluidized bed (DFB) gasification reactor. Fuels studied were mixtures of chicken litter together with wheat straw and bark, and mixtures of digested sewage sludge combined with wheat straw and sunflower husk. Ash fraction and bed materials were collected and analyzed using ICP-OES/MS, SEM-EDS and XRD techniques. For the mixture of chicken litter and K- and Si-rich wheat straw, combusted in BFB, P and Si together with K and Ca formed homogeneous ash particles with large amounts of potentially amorphous iv content. A similar behavior was observed in sewage sludge and wheat straw mixtures where P and Si were likely present in a melt that is amorphous after extraction. In addition to these particles, P was also found in crystalline compounds such as hydroxyapatite, whitlockite and CaKPO4. For mixtures with Ca-rich bark, most of the phosphate formed was in the form of hydroxyapatite. In the interaction of ash with bed material, P captures Ca and K in phosphates, decreasing the interactions of these elements with the bed material, and thus can decrease the risk for bed agglomeration. The findings show that it is possible to modify the ash transformation of P towards K-bearing phosphates by co-combustion. Furthermore, they suggest that it is possible to recover most of the phosphorus in coarse ash fractions through co-combustion of P-rich materials with agricultural fuels. This means that P and volatile heavy metals can be separated into different ash fractions. This also increases the possibility of utilizing existing boilers for recovery of P as well as increased their flexibility to different fuels. To further validate the agricultural value of the produced ashes, plant growth studies have to be performed.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2020
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
ash transformation, phosphorus recovery, sewage sludge, chicken manure
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-78593 (URN)978-91-7790-589-9 (ISBN)978-91-7790-590-5 (ISBN)
Presentation
2020-06-16, E632, House E, Luleå University of Technology, Luleå, 10:00 (English)
Opponent
Supervisors
Available from: 2020-04-21 Created: 2020-04-21 Last updated: 2023-09-05Bibliographically approved
Häggström, G., Fürsatz, K., Kuba, M., Skoglund, N. & Öhman, M. (2020). Fate of Phosphorus in Fluidized Bed Cocombustion of Chicken Litter with Wheat Straw and Bark Residues. Energy & Fuels, 34(2), 1822-1829
Open this publication in new window or tab >>Fate of Phosphorus in Fluidized Bed Cocombustion of Chicken Litter with Wheat Straw and Bark Residues
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2020 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, no 2, p. 1822-1829Article in journal (Refereed) Published
Abstract [en]

This study aims to determine the fate of P during fluidized bed co-combustion of chicken litter (CL) with K-rich fuels [e.g., wheat straw (WS)] and Ca-rich fuels (bark). The effect of fuel blending on phosphate speciation in ash was investigated. This was performed by chemical characterization of ash fractions to determine which phosphate compounds had formed and identify plausible ash transformation reactions for P. The ash fractions were produced in combustion experiments using CL and fuel blends with 30% CL and WS or bark (B) at 790–810 °C in a 5 kW laboratory-scale bubbling fluidized bed. Potassium feldspar was used as the bed material. Bed ash particles, cyclone ash, and particulate matter (PM) were collected and subjected to chemical analysis with scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM–EDS) and X-ray diffraction. P was detected in coarse ash fractions only, that is, bed ash, cyclone ash, and coarse PM fraction (>1 μm); no P could be detected in the fine PM fraction (<1 μm). SEM–EDS analysis showed that P was mainly present in K–Ca–P-rich areas for pure CL as well as in the ashes from the fuel blends of CL with WS or B. In the WS blend, P was found together with Si in these areas. The crystalline compound containing P was hydroxyapatite in all cases as well as whitlockite in the cases of pure CL and WS blend, of which the latter compound has been previously identified as a promising plant nutrient. The ash fractions from CL and bark blend only contained P in hydroxyapatite. Co-combustion of CL together with WS appears to be promising for P recovery, and ashes with this composition could be further studied in plant growth experiments.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2020
Keywords
Phosphates, Chemical reactions, Fuels, Reaction products, Materials
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-78115 (URN)10.1021/acs.energyfuels.9b03652 (DOI)000518215400072 ()2-s2.0-85080856092 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-03-20 (alebob)

Available from: 2020-03-20 Created: 2020-03-20 Last updated: 2023-09-05Bibliographically approved
Wagner, K., Häggström, G., Skoglund, N., Priscak, J., Kuba, M., Öhman, M. & Hofbauer, H. (2019). Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass. Applied Energy, 248, 545-554
Open this publication in new window or tab >>Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass
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2019 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 248, p. 545-554Article in journal (Refereed) Published
Abstract [en]

The use of phosphorus-rich fuels in fluidized bed combustion is one probable way to support both heat and power production and phosphorus recovery. Ash is accumulated in the bed during combustion and interacts with the bed material to form layers and/or agglomerates, possibly removing phosphorus from the bed ash fraction. To further deepen the knowledge about the difference in the mechanisms behind the ash chemistry of phosphorus-lean and phosphorus-rich fuels, experiments in a 5 kW bench-scale-fluidized bed test-rig with K-feldspar as the bed material were conducted with bark, wheat straw, chicken manure, and chicken manure admixtures to bark and straw. Bed material samples were collected and studied for layer formation and agglomeration phenomena by scanning electron microscopy combined with energy dispersive X-ray spectrometry. The admixture of phosphorus-rich chicken manure to bark changed the layer formation mechanism, shifting the chemistry to the formation of phosphates rather than silicates. The admixture of chicken manure to straw reduced the ash melting and agglomeration risk, making it possible to increase the time until defluidization of the fluidized bed occurred. The results also highlight that an increased ash content does not necessarily lead to more ash melting related problems if the ash melting temperature is high enough.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Phosphorus, Layer formation, Agglomeration, K-feldspar, Fluidized bed
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73937 (URN)10.1016/j.apenergy.2019.04.112 (DOI)000469891900044 ()2-s2.0-85064643200 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-14 (johcin)

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2023-09-05Bibliographically approved
Wagner, K., Häggström, G., Mauerhofer, A. M., Kuba, M., Skoglund, N., Öhman, M. & Hofbauer, H. (2019). Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure. Biomass and Bioenergy, 127, Article ID 105251.
Open this publication in new window or tab >>Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure
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2019 (English)In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 127, article id 105251Article in journal (Refereed) Published
Abstract [en]

Understanding layer formation on bed materials used in fluidized beds is a key step for advances in the application of alternative fuels. Layers can be responsible for agglomeration-caused shut-downs but they can also improve the gas composition in fluidized bed gasification. Layers were observed on K-feldspar (KAlSi3O8) impurities originating from the combined heat and power plant Senden which applies the dual fluidized bed (DFB) steam gasification technology. Pure K-feldspar was therefore considered as alternative bed material in DFB steam gasification. Focusing on the interactions between fuel ash and bed material, K-feldspar was tested in combustion and DFB steam gasification atmospheres using different fuels, namely Ca-rich bark, Ca- and P-rich chicken manure, and an admixture of chicken manure to bark. The bed particle layers formed on the bed material surface were characterized using combined scanning electron microscopy and energy-dispersive X-ray spectroscopy; area mappings and line scans were carried out for all samples. The obtained data show no essential influence of operational mode on the layer-formation process. During the combustion and DFB steam gasification of Ca-rich bark, a layer rich in Ca formed while K was diffusing out of the layer. The use of Ca- and P-rich chicken manure inhibited the diffusion of K, and a layer rich in Ca and P formed. The addition of P to bark via chicken manure also changed the underlying layer-formation processes to reflect the same processes as observed for pure chicken manure.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Fluidized bed, Layer formation, K-feldspar, Phosphorous, Combustion, DFB steam gasification
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-75063 (URN)10.1016/j.biombioe.2019.05.020 (DOI)000478564300032 ()2-s2.0-85066481346 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-27 (johcin)

Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2023-09-05Bibliographically approved
Wagner, K., Kuba, M., Häggström, G., Skoglund, N., Öhman, M. & Hofbauer, H. (2018). Influence of phosphorus on the layer formation on k-feldspar during fluidized bed combustion and gasification. Paper presented at 26th EU Biomass Conference & Exhibition, Copenhagen, 14-17 May 2018. European biomass conference and exhibition proceedings, 26thEUBCE, 486-492
Open this publication in new window or tab >>Influence of phosphorus on the layer formation on k-feldspar during fluidized bed combustion and gasification
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2018 (English)In: European biomass conference and exhibition proceedings, E-ISSN 2282-5819, Vol. 26thEUBCE, p. 486-492Article in journal (Refereed) Published
Abstract [en]

Today, mainly wood-based feedstocks are used in thermo-chemical biomass conversion since they have a comparably high heating value and contain a small amount of ash. Fluidized beds allow a greater variety of fuels to be used, since they are rather flexible regarding their fuel input. The use of biogenic waste streams (chicken manure, horse manure, etc.) and sewage sludge would not only increase the fuel diversity in fluidized beds but might also enhance the usability of side products. The contained essential nutrients like phosphorus, potassium, calcium, etc. in these fuels are enriched in the ash after thermochemical conversion. Thus, in the near future it may be possible to apply this ash as secondary resource for fertilizer. Especially the recovery of phosphorus is of importance due to the imminent phosphorus scarcity. Due to its tendency to react with ash forming elements in fuels, phosphorus influences the ash chemistry severely. Especially the agglomeration and layer formation on bed materials during biomass combustion and gasification is highly dependent on the predominant ash forming elements. Phosphorus therefore has a significant impact on those mechanisms. Until now, the behavior of phosphorus-rich fuels in fluidized beds has not been studied in much detail. To develop a basic understanding of the behavior, phosphorus-rich feedstock was combusted in a bench-scale fluidized bed reactor. Ash layers on bed particles, which were formed during these experiments, were studied and compared to results with phosphorus-lean fuels. Furthermore, layer formation of phosphorus-rich and phosphorus-lean fuels from dual fluid bed gasification were compared to those from fluidized bed combustion. The studied layers on bed materials showed significant amounts of phosphorus. The data also indicates a change in layer formation as soon as phosphorus is present. An increased catalytic activity due ash-layer formation was observed for both phosphorus-rich and phosphorus-lean feedstock, independent from the presence of phosphorus in the ash layer

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-70379 (URN)10.5071/26thEUBCE2018-2BO.6.2 (DOI)2-s2.0-85051038323 (Scopus ID)
Conference
26th EU Biomass Conference & Exhibition, Copenhagen, 14-17 May 2018
Available from: 2018-08-14 Created: 2018-08-14 Last updated: 2023-09-05Bibliographically approved
Kirtania, K., Häggström, G., Broström, M., Umeki, K. & Furusjö, E. (2017). Cogasification of Crude Glycerol and Black Liquor Blends: Char Morphology and Gasification Kinetics. Energy Technology, 5(8), 1272-1281
Open this publication in new window or tab >>Cogasification of Crude Glycerol and Black Liquor Blends: Char Morphology and Gasification Kinetics
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2017 (English)In: Energy Technology, ISSN 2194-4296, Vol. 5, no 8, p. 1272-1281Article in journal (Refereed) Published
Abstract [en]

This study assesses the feasibility of black liquor/glycerol blends as potential gasification feedstock. The char gasification reactivity and kinetics were studied at T = 750 °C, 800 °C, 850 °C and 900 °C for 20% and 40% blends of glycerol with black liquor. Three qualities of glycerol were used including two industrial grade crude glycerols. Gasification rates were similar for all blends, indicating sufficient alkali metal catalysis also for the char blends (Alkali/C atomic ratio between 0.45 and 0.55). The blends with the most impure glycerol (containing K) were found to have the lowest activation energies (~120 kJ/mol) and reaction times for char gasification indicating fuel properties suitable for gasification. Char particles from different blends showed similar surface morphology as black liquor chars with even surface distribution of alkali elements. A loss of alkali (mainly, K) from the fuel blends during pyrolysis indicated the necessity to perform gas-phase studies of alkali release. Overall, these results encourage the use of glycerol as a potential gasification feedstock for catalytic gasification based bio-refineries.  

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
Keywords
alkali, gasification, black liquor, glycerol, kinetics
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-59768 (URN)10.1002/ente.201600569 (DOI)000407591200020 ()2-s2.0-85010628698 (Scopus ID)
Projects
LTU Area of Excellence in Research and Innovation - Renewable Energy
Note

Validerad;2017;Nivå 2;2017-08-16 (inah)

Available from: 2016-10-15 Created: 2016-10-15 Last updated: 2023-05-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5420-965x

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