Critical review of predictive coefficients for biomass ash deposition tendency

The circulating fluidized bed (CFB) boiler is a mainstream technology of biomass combustion generation in China. The high flue gas flow rate and relatively low combustion temperature of CFB make the deposition process different from that of a grate furnace. The dynamic deposition process of biomass ash needs further research, especially in industrial CFB boilers. In this study, a temperature-controlled ash deposit probe was used to sample the deposits in a 12 MW CFB boiler. Through the analysis of multiple deposit samples with different deposition times, the changes in micromorphology and chemical composition of the deposits in each deposition stage can be observed more distinctively. The initial deposits mainly consist of particles smaller than 2 μm, caused by thermophoretic deposition. The second stage is the condensation of alkali metal. Different from the condensation of KCl reported by most previous literatures, KOH is found in deposits in place of KCl. Then, it reacts with SO2, O2 and H2O to form K2SO4. In the third stage, the higher outer layer temperature of deposits reduces the condensation rate of KOH significantly. Meanwhile, the rougher surface of deposits allowed more calcium salts in fly ash to deposit through inertial impact. Thus, the elemental composition of deposits surface shows an overall trend of K decreasing and Ca increasing.

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Use of biomass ash-based materials as soil fertilisers: Critical review of the existing regulatory framework

Journal of Cleaner Production ◽

10.1016/j.jclepro.2018.12.268 ◽

2019 ◽

Vol 214 ◽

pp. 112-124 ◽

Cited By ~ 18

Author(s):

Flávio C. Silva ◽

Nuno C. Cruz ◽

Luís A.C. Tarelho ◽

Sónia M. Rodrigues

Keyword(s):

Critical Review ◽

Regulatory Framework ◽

Biomass Ash

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Study on the Predicting Technique of Ash Deposition Tendency in the Entrained-Flow Coal Gasifier. 2nd Report. The Analytical Results of Ash Deposition Tendency in a 2T/D Coal Gasifier Using Numerical Simulation Code with Ash Adhension Model.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.67.2783 ◽

2001 ◽

Vol 67 (663) ◽

pp. 2783-2790

Author(s):

Kazuyoshi ICHIKAWA ◽

Hiroaki WATANABE ◽

Maromu OTAKA ◽

Jun INUMARU

Keyword(s):

Numerical Simulation ◽

Ash Deposition ◽

Simulation Code ◽

Entrained Flow ◽

Coal Gasifier ◽

Analytical Results ◽

Deposition Tendency

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Assessment of ash deposition tendency in a rotary kiln using Thermo-mechanical analysis and Experimental Combustion Furnace

Fuel ◽

10.1016/j.fuel.2014.06.064 ◽

2014 ◽

Vol 135 ◽

pp. 301-307 ◽

Cited By ~ 16

Author(s):

Rakhi Bandyopadhyay ◽

Sushil Gupta ◽

Bo Lindblom ◽

Samuel Jonsson ◽

David French ◽

...

Keyword(s):

Rotary Kiln ◽

Mechanical Analysis ◽

Ash Deposition ◽

Deposition Tendency ◽

Experimental Combustion

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Experimental Investigation of the Ash Deposition Characteristics of Biomass Pretreated by Ash Removal during Co-Combustion with Sub-Bituminous Coal

Energies ◽

10.3390/en14217391 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7391

Author(s):

Dae-Gyun Lee ◽

Min-Jong Ku ◽

Kyeong-Ho Kim ◽

Jae-Sung Kim ◽

Seung-Mo Kim ◽

...

Keyword(s):

Bituminous Coal ◽

Removal Rate ◽

Unburned Carbon ◽

Total Biomass ◽

Drop Tube ◽

Ash Deposition ◽

Biomass Ash ◽

Internal Corrosion ◽

Before And After ◽

Ash Removal

Although replacing biomass, (e.g., wood chips and pellets), with thinning wood and herbaceous biomass is eco-friendly and economically advantageous, their direct utilization in plant boilers is associated with ash-related challenges, including slagging and fouling. The aim of this study is to determine the effects of ash removal treatment (ashless biomass (ALB)) in the context of solid fuel power plant boilers. Ash was removed via neutralization of metal ions and carboxylic acids contained in the biomass ash. The ash removal rate of K, Na, Cl was indicated by assessing the total biomass before and after ash removal treatment, via XRF analysis. Co-combustion with sub-bituminous coal and ALB-treated biomass was analyzed using a drop tube furnace and revealed that NOx and SOx values converged converge toward an approximate 10 ppm error, whereas the Unburned Carbon (UBC) data did not exhibit a specific trend. Factors associated with slagging and fouling, (capture efficiency (CE), and energy based growth rate (GRE)) were calculated. All biomass samples without pretreatment exhibited V-shaped variation. Conversely, for ashless biomass (ALB) samples, CE and GRE gradually decreased. Thus, the ALB technique may minimize slagging and fouling in a boiler, thus, reducing internal corrosion associated with ash deposition and enhancing the economic operation of boilers.

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Influence of kaolin and coal fly ash addition on biomass ash deposition in an entrained flow reactor

Fuel ◽

10.1016/j.fuel.2021.123041 ◽

2022 ◽

Vol 313 ◽

pp. 123041

Author(s):

Guoliang Wang ◽

Jesper Naimi Funch Poulsen ◽

Samira Naimi Funch Poulsen ◽

Peter Arendt Jensen ◽

Flemming Jappe Frandsen

Keyword(s):

Fly Ash ◽

Flow Reactor ◽

Coal Fly Ash ◽

Ash Deposition ◽

Biomass Ash ◽

Entrained Flow ◽

Entrained Flow Reactor

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Dynamic Behavior of Biomass Ash Deposition in a 25 kW One-Dimensional Down-Fired Combustor

Energy & Fuels ◽

10.1021/ef401530a ◽

2013 ◽

Vol 28 (1) ◽

pp. 219-227 ◽

Cited By ~ 23

Author(s):

Gengda Li ◽

Shuiqing Li ◽

Xiaoguang Xu ◽

Qian Huang ◽

Qiang Yao

Keyword(s):

Dynamic Behavior ◽

Ash Deposition ◽

Biomass Ash ◽

One Dimensional

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Optimal strategy for clean and efficient biomass combustion based on ash deposition tendency and kinetic analysis

Journal of Cleaner Production ◽

10.1016/j.jclepro.2020.122529 ◽

2020 ◽

Vol 271 ◽

pp. 122529 ◽

Cited By ~ 1

Author(s):

Qianqian Guo ◽

Zhanjun Cheng ◽

Guanyi Chen ◽

Beibei Yan ◽

Li’an Hou ◽

...

Keyword(s):

Kinetic Analysis ◽

Optimal Strategy ◽

Biomass Combustion ◽

Ash Deposition ◽

Deposition Tendency

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Modelling of initial deposition of biomass ash particles on walls of superheater tubes

Thermal Science ◽

10.2298/tsci200311270w ◽

2020 ◽

Vol 24 (6 Part A) ◽

pp. 3489-3499

Author(s):

Yibin Wang ◽

Hexin Liu ◽

Houzhang Tan

Keyword(s):

Deposition Rate ◽

Tube Bundle ◽

Windward Side ◽

Leeward Side ◽

Computational Domain ◽

Ash Deposition ◽

Condensation Rate ◽

Biomass Ash ◽

Alkali Chloride ◽

Initial Deposition

Condensation of gaseous alkali chloride and sulphate and adhesion of molten ash particles are still an important issue of investigation and gaining more and more attention in biomass utilization. In this work the behaviours for formation of initial deposition layer and condensation of KCl(g) and K2SO4(g) were simulated nu-merically in a 2-D computational domain of an in-line 4?4 tube bundle. The sticking and rebound efficiency of incident particles, condensation rate of gaseous salts and ash deposition rate on both of the windward and the leeward sides of tubes were obtained through transient calculation cases. The ash deposition mass on the windward side of tubes is mainly from impaction and stickiness of large ash particles. The condensation rate of KCl(g) is two orders of magnitude higher than that of K2SO4(g) on both of the windward and the leeward side of tubes. The ash deposition rate and the condensation rate on the windward side of tubes are of equal importance. While on the leeward side of tubes the condensation of salt vapours is more dominant than the inertial impaction in the forming stage of initial layer.

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