Early Layer Formation on K-Feldspar During Fluidized Bed Combustion with Phosphorus-Rich Fuel

Faust, Robin; Fürsatz, Katharina; Aonsamang, Panida; Sandberg, Marcus; Kuba, Matthias; Skoglund, Nils; Knutsson, Pavleta

doi:10.2139/ssrn.4061488

Cited by 1 publication

(5 citation statements)

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“…The association of phosphorus in biomass ash and char has been studied by numerous researchers. However, Öhman (refs , , , , , , , , , , , , , , , – ), Boström (refs , , , , , , , , , , , , – , – ), Skoglund (refs , , , , , , , , , , , , – , – , ), and their co-workers have performed considerable work within the field and should be acknowledged for investigating the fate of phosphorus in various types of biomass, and the combustion characteristics of several phosphorus-rich biomass types. In this section, a conceptual model developed by them, to aid the understanding of phosphorus transformation(s) in biomass ash, will first be presented.…”

Section: Transformation Of Phosphorus In Biomass Conversionmentioning

confidence: 99%

“…Performing investigations using fixed bed setups may indicate whether any reactions are taking place between the bed material and model compound. However, the high levels of alkali used in fixed bed studies, 3–16 wt %, ,, may not be representative for the quantities required for defluidization, which was shown to be in the range 0.1–0.3 wt % for alkali metaphosphates and 0.4–1.4 wt % for alkali orthophosphates under similar conditions . In a fixed bed study, the level of agglomeration resulting from addition of 12 wt % NH 4 H 2 PO 4 to a silica bed was rated to be 2 (on a scale from 0 to 5, where 2 represents agglomerates that can be broken by compressive force of less than 10 N), when treated at temperatures in the range of 650–950 °C .…”

Section: Application Aspectsmentioning

confidence: 99%

“…Faust et al investigated the interaction between K-feldspar and the model compounds K 3 PO 4 , Na 3 PO 4 , CaHPO 4 , and Mg 3 (PO 4 ), in a fixed bed at 830 °C using a holding time of 24 h. The tests with alkaline earth phosphates did not display any interactions with K-feldspar, but agglomeration was observed for the alkali phosphates . The agglomeration mechanism was suggested to be melt induced because the interparticle material in the experiment with K 3 PO 4 had a potassium to phosphorus ratio of about 2.5, which is close to the original composition of K 3 PO 4 . However, K 3 PO 4 and Na 3 PO 4 have melting temperatures of 1619 and 1579 °C, respectively, so some kind of chemical reaction between the bed material and alkali phosphates must have taken place to form a phase with a lower melting temperature.…”

Section: Application Aspectsmentioning

confidence: 99%

“…To understand how phosphates interact with bed material, to potentially cause particle agglomeration and bed defluidization, a number of studies applying model compounds were performed. The model compounds include NH 4 H 2 PO 4 , , KH 2 PO 4 , ,,,, NaH 2 PO 4 , ,, H 3 PO 4 (in combination with NaNO 3 ), Ca(H 2 PO 4 ) 2 , CaHPO 4 , , K 3 PO 4 , , Na 3 PO 4 , , Ca 3 (PO 4 ) 2 , and Mg 3 (PO 4 ) 2 . Primarily silica sand ,,− , was used as a bed material, but a single study using K-feldspar was also performed …”

Section: Application Aspectsmentioning

confidence: 99%

“…The model compounds include NH 4 H 2 PO 4 , , KH 2 PO 4 , ,,,, NaH 2 PO 4 , ,, H 3 PO 4 (in combination with NaNO 3 ), Ca(H 2 PO 4 ) 2 , CaHPO 4 , , K 3 PO 4 , , Na 3 PO 4 , , Ca 3 (PO 4 ) 2 , and Mg 3 (PO 4 ) 2 . Primarily silica sand ,,− , was used as a bed material, but a single study using K-feldspar was also performed …”

Section: Application Aspectsmentioning

confidence: 99%

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Review of Phosphorus Chemistry in the Thermal Conversion of Biomass: Progress and Perspectives

et al. 2023

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Phosphorus is vital for all life, which means that phosphorus is present in all biomass to some extent. Some types of biomass, such as certain agricultural residues, animal biomass, and sewage sludge, contain high levels of phosphorus. In thermal conversion of biomass, high levels of phosphorus can cause various operational problems. Extensive work has been carried out to understand the phosphorus chemistry taking place at higher temperatures. However, until now, knowledge about transformation chemistry and fate of phosphorus during thermal conversion of biomass was not easily accessible in one place. In this work, the outcome of an extensive literature review has been summarized. First, an introduction to the role of phosphorus in biomass, and in what forms it may be present, is given. Different analytical techniques relevant for characterization of phosphorus in biomass, biomass char, and biomass ash are described. A classification of phosphorus-rich biomass is proposed, and the potential of different phosphorus-rich biomass types is presented. To provide a common basis for the field of high-temperature phosphorus chemistry, fundamental chemistry relevant for thermal conversion of biomass is first discussed. This includes the gas phase chemistry and reaction pathways of light phosphorus species, pyrolysis, and combustion of organophosphorus compounds, and solid, liquid, and gaseous interactions with other ash-forming elements. Thereafter, an in-depth review of phosphorus transformations in biomass, including decomposition of organic phosphorus, ash transformations in the condensed phase, release to the gas phase, and formation of particulate matter in the flue gas follows. Finally, the review covers research focusing on phosphorus in different application aspects, such as the use of phosphorus as an additive to mitigate operational problems related to slag and deposit formation, the behavior of phosphorus in fluidized bed technologies, corrosion, and the deactivation of SCR catalysts.

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