Effect of particle size distribution on agglomeration/defluidization during fluidized bed combustion

Lin, Chong; Peng, Tzu-Huan; Wang, Wei-Jen

doi:10.1016/j.powtec.2010.11.010

Cited by 55 publications

(31 citation statements)

References 29 publications

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“…The event of defluidization can be estimated by the change in pressure drop because the bed pressure drop is proportional to the bed inventory (Chaivatamaset et al, 2011). The pressure drop fluctuates around an average when the FBC running steady, but the pressure drop falls rapidly after defluidization starts (Atakül et al, 2005;Billen et al, 2014;Lin et al, 2011). Scala and Chirone (2005) thermocouples, located vertically at various heights in the bed, to measure the temperature difference.…”

Section: Introductionmentioning

confidence: 99%

Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor

Duan

Chyang

Zhang

et al. 2015

Bioresource Technology

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Section: Introductionmentioning

confidence: 99%

Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor

Duan

Chyang

Zhang

et al. 2015

Bioresource Technology

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“…Chaivatamaset, et al [64] found that increases to U of 28% and 60%, led to 539 average increases of tdef for two different fuels of 56% and 95% respectively. Lin, et al [65] recorded 540 increases in tdef with successive increments in U, across four types of particle size distribution 541 (narrow, Gaussian, binary flat). Yu, et al…”

mentioning

confidence: 99%

Mechanisms and mitigation of agglomeration during fluidized bed combustion of biomass: A review

Morris

Chilton

Nimmo

2018

Fuel

118

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11A key issue associated with Fluidized Bed Combustion of biomass is agglomeration. The presence of 12 high quantities of alkali species in biomass ash leads to the formation of sticky alkali-silicate liquid 13 phases during combustion, and consequently the adhesion and agglomeration of bed material. This 14 review principally examines probable mechanisms of agglomeration and the effects of operational 15 variables in reducing its severity. Additionally, an overview of monitoring and prediction of 16 agglomerate formation is given. Two key mechanisms of agglomeration are apparent in literature, 17 and both may occur concurrently dependent on fuel composition. Coating-induced agglomeration is 18 defined by the interaction of alkali metals in fuel ash with the bed material, commonly silica sand, to 19 form an alkali-silicate melt. Melt-induced agglomeration is defined by the presence of sufficient 20 amounts of both alkali compounds and silica liquid phases sourced from the fuel ash to form a 21 eutectic mixture. Physical mechanisms, such as tumble agglomeration and sintering, may further 22 enhance either of the coating-induced or melt-induced mechanisms. Of the operational variables volumes of non-combustible contaminants, high moisture contents and, in most applications, 63 requires a large amounts of pre-processing/pre-treatment with specialised transportation. Due to 64 these challenges, technologies such as fluidized bed combustion (FBC) boilers have been employed. 65 FBC offers a number of advantages, such as combustion of different fuel types, blends, and ranges of 66 qualities, features commonly referred to under the umbrella term of [5]. Hundreds 67 Page 4 of 75 of full-scale bubbling fluidized bed (BFB) [6, p. 7] and circulating fluidized bed (CFB) [6, p. 8] boilers 68have been deployed around the world [7, 8] for power generation and/or steam sales to industrial or 69 chemical plant sites. However, each FBC plant development has to overcome slagging, fouling, 70 corrosion and, most significantly, agglomeration issues resulting from the composition and 71 behaviour of the biomass fuel stock [9]. 72

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“…These factors include (a) operation related parameters such as particle size, operating temperature, and fluidization velocity [6,49]; and (b) mineral matter composition [49][50][51]. All these factors affect the initial sintering temperature and/or contribute to minimum "critical thickness" of the sticky coating on the bed particles.…”

Section: Fluidized Bed Gasifiersmentioning

confidence: 99%

“…This results in too high of a concentration of sodium in the gasifier, which can also transfer it to the bed material causing extensive agglomeration problems. Moreover, presence of a wide range of particle size distribution in the gasifier can lead to poor particle mixing and thereby increasing the possibility of agglomeration and defluidization [49]. Therefore, an additive that does not fragment extensively can be suitable for the process.…”

Section: Strategies To Minimize Agglomeration and Ash Depositionmentioning

confidence: 99%

A Critical Review of Mineral Matter Related Issues during Gasification of Coal in Fixed, Fluidized, and Entrained Flow Gasifiers

Krishnamoorthy

Pisupati

2015

Energies

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Gasification of coal is gaining more popularity due to its clean operation, and its ability to generate products for various markets. However, these technologies are not widely commercialized due to reliability and economic issues. Mineral matter in coal plays an important role in affecting the availability/reliability of a gasifier. Agglomeration in the bed, slag mobility and blockage of the syngas exit section are some of the operations related concerns in fixed-bed gasifiers, while ash deposition and sudden defluidization are the major concerns in fluidized bed gasifiers. In the case of entrained flow gasifiers, syngas cooler fouling and blockage, corrosion and erosion of refractory, and slag mobility are some of the major issues affecting the operations and the reliability of the gasifier. This review is aimed at critically examining various mineral matter related issues contributing to the operation and reliability problems in three types of generic gasifiers (fixed bed, fluidized bed and entrained flow gasifiers). Based on the review, some strategies to counter the potential mineral matter related issues are presented.

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Effect of particle size distribution on agglomeration/defluidization during fluidized bed combustion

Cited by 55 publications

References 29 publications

Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor

Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor

Mechanisms and mitigation of agglomeration during fluidized bed combustion of biomass: A review

A Critical Review of Mineral Matter Related Issues during Gasification of Coal in Fixed, Fluidized, and Entrained Flow Gasifiers

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