The use of kaolin and dolomite bed additives as an agglomeration mitigation method for wheat straw and miscanthus biomass fuels in a pilot-scale fluidized bed combustor

Morris, Jonathan D.; Daood, Syed Sheraz; Nimmo, W.

doi:10.1016/j.renene.2022.06.151

Cited by 18 publications

(6 citation statements)

References 40 publications

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“…Wheat straw is a type of feedstock that has received significant attention in the field of agglomeration, which is due to its typical melting-induced agglomeration mechanism. Agglomeration tendency of wheat straw was tested the most under combustion conditions,, ,,, air gasification, ,, and steam gasification, , whereas that under CO 2 gasification is very limited. It was found previously that the higher the ash content of the wheat straw or/and the higher the temperature, the stronger the agglomerates are.…”

Section: Results and Discussionmentioning

confidence: 99%

“…33 In contrast, other studies suggest that there is no difference in the bed agglomeration tendency of wheat straw regardless of the use of different bed materials or additives. 27,79 The wheat straw samples used in this study are characterized by the high concentration of Si and K but low in Ca and therefore exhibit typical melting-induced agglomeration as a result of ashderived K-silicate melts. This could explain why defluidization was still induced with wheat straw under the combustion conditions, even when non-silica-based olivine sand was used as the bed material.…”

Section: Agglomeration Mechanism With Wheat Strawmentioning

confidence: 99%

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Agglomeration of Olivine with Potassium- or Silicon-Rich Agricultural Residues Under Conditions Relevant to Dual Fluidized Bed Gasification

Nathan

Kuba

et al. 2022

Energy Fuels

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The agglomeration characteristics of olivine-and potassium (K)-rich grape marc or silicon (Si)-rich wheat straw were studied in a laboratory-scale fluidized reactor and compared under air combustion, steam gasification, or CO 2 gasification atmospheres at temperatures relevant to a dual fluidized bed gasifier. Agglomeration with grape marc is found to be induced mostly by the formation of adhesive K-rich layers onto the olivine, a process that is significantly augmented in a steam atmosphere compared to that in the air or CO 2 . The formation of an initial Krich outer layer, which is caused by the mere physical attachment of K-species onto the olivine surface, facilitated the formation of an inner layer. This inner layer exhibits chemical reactions between grape marc ash and olivine, with the ash elements involved in the chemical reactions differing between combustion and steam gasification environments. Agglomeration with a wheat straw is most significant under air combustion conditions and depends primarily on the temperature rather than on the atmosphere.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Agglomeration Mechanism With Wheat Strawmentioning

confidence: 99%

Agglomeration of Olivine with Potassium- or Silicon-Rich Agricultural Residues Under Conditions Relevant to Dual Fluidized Bed Gasification

Nathan

Kuba

et al. 2022

Energy Fuels

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“…Halloysite and kaolin were found to be more efficient remedies for the defluidization process than the limestone and desulfurization residues, also investigated in this study. Similarly, kaolin was proven to prevent bed defluidization by Morris et al [81] during the combustion of miscanthus. According to the SEM/EDX analysis of agglomerates, the evident chemical reactions between kaolin and fuel occurred as potassium was found to migrate into the kaolin particle at depths of up to 60 µm.…”

Section: Aluminosilicate Clay Minerals In Fluidized Bed Combustionmentioning

confidence: 91%

Aluminosilicate Clay Minerals: Kaolin, Bentonite, and Halloysite as Fuel Additives for Thermal Conversion of Biomass and Waste

Maj

Matus

2023

Energies

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The current focus on renewable energy sources and the circular economy favors the thermal conversion of low-quality fuels, such as biomass and waste. However, the main limitation of their usability in the power sector is the risk of slagging, fouling, ash deposition, and high-temperature corrosion. These problems may be avoided or significantly mitigated by the application of aluminosilicate clay minerals as fuel additives. In this paper, the three most commonly occurring aluminosilicates are reviewed: kaolin, halloysite, and bentonite. Their application has been proven to minimize combustion-related problems by bonding alkalis in high-melting compounds, thus increasing ash melting temperatures, reducing ash deposition tendencies, and decreasing the particulate matter emission. Due to excellent sorption properties, aluminosilicates are also expected to fix heavy metals in ash and therefore decrease their emissions into the atmosphere. The application of aluminosilicates as fuel additives may be a key factor that increases the attractiveness of biomass and other low-quality fuels for the power sector.

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“…In general, agricultural biomass releases more AAEMs into the gas phase during combustion compared to forestry biomass be cause agricultural biomass contains higher levels of water-soluble AAEMs, which have lower melting points. Additionally, an increase in phosphorus (P) content in the feedstock can reduce the evaporation of K. Many studies add phosphorus-containing substances as adsorption inhibitors for K because K forms stable K-Ca/Mg-P minerals during combus tion [45,46]. Similarly, elements such as silicon (Si) and aluminum (Al) have similar effects The use of kaolin (a high-Si material) as a K adsorbent is well documented, as K forms This method allows for the obtaining of solutions containing four different forms of AAEMs, i.e., water-soluble, ion-exchangeable, acid-soluble, and insoluble [41,42].…”

Section: The Influence Of Inherent Mineral Matter In Feedstockmentioning

confidence: 99%

AAEM Species Migration/Transformation during Co-Combustion of Carbonaceous Feedstocks and Synergy Behavior on Co-Combustion Reactivity: A Critical Review

Jiao,

Tian,

et al. 2023

Energies

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Co-combustion is a crucial route for the high-efficiency utilization and clean conversion of different carbonaceous feedstocks (biomass, coal, petroleum coke, etc.). The migration and transformation of alkali and alkaline earth metals (AAEMs) are not only related to ash-related issues in actual application, but also directly affect the reaction behavior of binary particles during co-conversion. This review paper summarizes research progress in the detection methods (online and offline) and influencing factors (feedstock type, feedstock blending ratio, reaction temperature, reaction time) of AAEMs migration and transformation during the co-combustion of carbonaceous feedstocks. Furthermore, it provides a detailed summary of research progress on factors (feedstock blending ratio, heating rate, etc.) influencing the co-combustion reactivity of carbonaceous feedstocks, synergy behavior, and its mechanisms. The influence of feedstock type on AAEMs migration and transformation during co-combustion is mainly related to the composition categories, chemical forms and contents of intrinsic mineral in binary feedstocks. The increase in the combustion temperature will intensify the release of inherent AAEMs in carbonaceous feedstocks, and promote AAEM deactivation. For high K and Cl-containing biomass, a higher biomass proportion in blends would result in more AAEMs release during the co-combustion process. Conversely, an increase in coal proportion in blends will directly favor the reduction or inhibition of AAEMs release. Synergy behavior during co-pyrolysis and subsequent char co-combustion is usually presented as an inhibition effect and an synergistic effect, respectively. The synergistic mechanisms of carbonaceous feedstock co-combustion reactions can be divided into two categories: non-catalytic synergistic mechanisms related to the excitation and migration of biomass-based free radicals and catalytic synergistic mechanisms related to biomass-based AAEMs catalysis. Additionally, future research prospects are also proposed based on the systematic review.

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The use of kaolin and dolomite bed additives as an agglomeration mitigation method for wheat straw and miscanthus biomass fuels in a pilot-scale fluidized bed combustor

Cited by 18 publications

References 40 publications

Agglomeration of Olivine with Potassium- or Silicon-Rich Agricultural Residues Under Conditions Relevant to Dual Fluidized Bed Gasification

Agglomeration of Olivine with Potassium- or Silicon-Rich Agricultural Residues Under Conditions Relevant to Dual Fluidized Bed Gasification

Aluminosilicate Clay Minerals: Kaolin, Bentonite, and Halloysite as Fuel Additives for Thermal Conversion of Biomass and Waste

AAEM Species Migration/Transformation during Co-Combustion of Carbonaceous Feedstocks and Synergy Behavior on Co-Combustion Reactivity: A Critical Review

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