Biomass Ash Fluidised-Bed Agglomeration: Hydrodynamic Investigations

Balland, M.; Froment, Karine; Ratel, G.; Valin, Sylvie; Roussely, Julien; Michel, Rudy; Poirier, Jacques; Kara, Y.; Galnares, A.

doi:10.1007/s12649-017-9853-9

Cited by 8 publications

(14 citation statements)

References 26 publications

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“…The most significant ash-forming elements in biomass are silica (Si), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), phosphor (P), chlorine (Cl), sodium (Na) and sulphur (S). (Balland et al, 2017;Furuvik et al, 2020). The ashforming elements are released from the biomass during the heating process.…”

Section: Ash Melting and Agglomeratesmentioning

confidence: 99%

Computational modeling of fluidized bed behavior with agglomerates

Jakobsen¹,

Jaiswal²,

Furuvik³

et al. 2021

Linköping Electronic Conference Proceedings

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Fluidized bed reactors can be used for biomass gasification. The product from biomass gasification is syngas, which can be used for production of bio oil. The main challenge when using fluidized bed for gasification is ash melting and agglomeration of the bed material. Agglomeration of the bed material influences on the flow behavior in the fluidized bed reactor and thus affects the gasification efficiency. A Computational Particle Fluid Dynamic (CPFD) model is developed to predict the flow behavior in a fluidized bed gasifier. The CPFD model was validated against experimental data from a cold fluidized bed. The model was then tested against the results from a biomass gasifier, and a few modifications were needed. Glickman's scaling parameters were used to scale up from a lab-scale to a full-scale gasifier. Simulations using the modified model were performed to study the flow behavior in a full-scale gasifier with agglomerates. It was found that the CPFD model is capable of predicting the effect of agglomerates on flow behavior in a fluidized bed gasifier.

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Section: Ash Melting and Agglomeratesmentioning

confidence: 99%

Computational modeling of fluidized bed behavior with agglomerates

Jakobsen¹,

Jaiswal²,

Furuvik³

et al. 2021

Linköping Electronic Conference Proceedings

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“…Ash melting behavior from laboratory prepared ash from the grass pellets was determined according to the CEN/TS 15730-1:2006. Generally, the ash melting takes place over a melting range where the solid phase coexists with its liquid phase [2]. The ash melting behavior is useful to make a qualitative statement about the agglomeration tendency of the fuel at given temperatures.…”

Section: Fuel and Bed Materials Characteristicsmentioning

confidence: 99%

“…Fluidized beds offer homogenous operation conditions and excellent fuel/gas contact, and are therefore ideally suited for converting biomass into an energy-rich synthetic gas. The produced gas has several applications, and can be used either directly for production of heat and power or it can be further processed into biofuels and other conventional chemicals [2].…”

Section: Introductionmentioning

confidence: 99%

“…Particle agglomeration during gasification of biomass in fluidized beds typically originates from certain ash-forming elements, which are released from the biomass during the heating process. The most significant ash-forming elements in biomass are silica (Si), potassium (K), calcium (Ca), magnesium (Mg), aluminium (Al), phosphor (P), chlorine (Cl), sodium (Na) and sulphur (S) [2]. The tendency of particles to agglomerate is highly coupled to the physical characteristics and the high temperature chemistry of the biomass ash.…”

Section: Introductionmentioning

confidence: 99%

“…The second mechanism is the condensation of volatilized ash on the bed particles, while the third mechanism is the attachment of molten or partially molten ash to the surface of the bed particles due to chemical reactions between the gaseous alkali components and the particles (solid ash + bed material) [5]. The ash melting and following agglomeration process depends on the ash characteristics, and can also be influenced by the bed operation conditions or the nature of the bed material [2]. In most ash-layer coatings, Si is the dominating element [5].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study of Agglomeration of Grass Pellets in Fluidized Bed Gasification

Furuvik

Jaiswal

Moldestad

2020

WIT Transactions on Ecology and the Environment

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The agglomeration tendency during gasification of grass pellets in a bubbling fluidized bed reactor was studied. Particle agglomeration occurs as a consequence of interactions between the bed particles and the biomass ash during the thermal conversion of biomass in fluidized beds. The continuous operation and high efficiency of the fluidized beds are in these cases limited by partial or complete de-fluidization.In order to study the agglomeration tendency of grass pellets at defined operating conditions, controlled agglomerations tests are performed in a laboratory scaled 20 kW bubbling fluidized bed reactor. The effect of the ratio between the superficial fluidization velocity (u0) and the minimum fluidization velocity (umf) on the agglomeration tendency for grass pellets is reported. The results show that agglomeration in the bed can be recognized by fluid dynamic disturbances in the bed, and if not counteracted, de-fluidization will occur. The ratio u0/umf influences the agglomeration tendency and the de-fluidization of bed. As the ratio u0/umf increases, the agglomeration tendency and the de-fluidization time decreases. The de-fluidization temperature was not influenced by the changes in the superficial velocity ratio.

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