Impact of KCl impregnation on single particle combustion of wood and torrefied wood

Lü, Zhimin; Jian, Jie; Jensen, Peter Arendt; Wu, Hao; Glarborg, Peter

doi:10.1016/j.fuel.2017.05.082

Cited by 17 publications

(12 citation statements)

References 38 publications

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“…Devolatilization is an important step for both ignition and burnout of biomass particles during combustion. Several experimental studies [5][6][7][8][9] have been done to investigate biomass devolatilization under high-temperature conditions (1200℃) that are representative for pulverized biomass combustion [5,[7][8][9]. The existing studies found that the devolatilization time of biomass particles decreases with increasing gas temperature and oxygen concentration [5], and increases with increasing particle size [5][6][7][8], moisture content [7] and density [8,9].…”

Section: Introductionmentioning

confidence: 99%

Experimental and modelling study on the influence of wood type, density, water content, and temperature on wood devolatilization

Luo

Lü

Jensen

et al. 2020

Fuel

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Wood devolatilization experiments in a single particle combustor and comparison with a 1D devolatilization model were carried out to investigate the effects of wood particle properties and operation conditions on wood particle devolatilization time. The experiments were conducted with 3 mm spherical/cubic and 4 mm spherical particles at gas temperatures of 1200-1450°C and oxygen contents of 0-4.4 vol%. Both experimental and modelling results showed that the devolatilization time increases linearly with particle density for raw, wetted, and torrefied wood particles. A sensitivity analysis done with the 1D devolatilization model showed that the biomass devolatilization time is sensitive to particle size, moisture content, gas temperature and particle density, and insensitive to volatiles fraction and gas velocity under the investigated experimental conditions. Using the same devolatilization kinetics, the 1D model could predict well the devolatilization time of different wood species with different particle size, density and moisture content. With this in mind, a simple correlation for devolatilization time has been developed based on the simulation data from the 1D model. The correlation uses a four-variable function with input of particle size, moisture content, gas temperature and particle density to determine the devolatilization time of biomass. Experimental devolatilization time found in literature could be predicted within ±25% for large particles (1 mm-10 mm) under high temperature conditions (1000℃-1600℃).

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Section: Introductionmentioning

confidence: 99%

Experimental and modelling study on the influence of wood type, density, water content, and temperature on wood devolatilization

Luo

Lü

Jensen

et al. 2020

Fuel

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“…The combustion of the released volatiles happens relatively fast within the visual ame, while the char combustion is a more time consuming process. 1,2 Consequently, it is important to know the fractions of volatiles and char for prediction of the burnout of the fuel. The volatile and char fractions are also often used as input parameters in combustion models.…”

Section: Introductionmentioning

confidence: 99%

“…A comparison of the model statistics with and without char yield data above 15 wt% daf and the original straw data can be seen in table 5. The expression for straw char yield can be seen in equation(2).The equation has not been validated against an external validation set and should thus be used more cautiously than the model for wood biomass, especially if the potassium content is vastly dierent in the sample one wants to predict the char yield of.Here CY straw is the char yield in wt%daf, KC is the potassium content in wt%db, F T is the nal temperature in K, and HR is the heating rate in K/s.…”

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confidence: 99%

Predicting Biomass Char Yield from High Heating Rate Devolatilization Using Chemometrics

2018

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This study provides a simple model for biomass char yield obtained under conditions relevant for suspension ring. Using the multivariate data analysis methods, principal component analysis (PCA) and partial least squares regression (PLS regression), an equation is presented, which predict the char yield for wood and herbaceous biomass. The model parameters are heating rate (0.1-12 •10 3 K/s), average particle size (0.13-0.93 mm), maximum temperature (873-1673 K), potassium content (from 0.02 wt% db and upwards), and char yield (1-15 wt% daf). The model is developed based on wood biomass data and subsequently expanded to include straw and other herbaceous biomass. It is validated against experimental data from the literature and in general it exhibits the same characteristics. Independent data sets of wood are predicted with an average error (RMSEP) of 0.9 wt%point daf, and straw with an RMSEP = 0.9 wt% daf for the model, when a slope/intercept correction is applied, or RMSEP = 1.1 wt% daf otherwise. To include herbaceous biomass, the model introduces a potassium cut o level at 0.53wt%db, because the catalytic eect of potassium on the devolatilization 1

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“…The torrefaction process is used for thermal valorization of solid fuels, thus improving their properties, and in consequence, promoting sustainability in the energy generation sector [41][42][43]. Torrefaction is sometimes called slow pyrolysis, and it typically takes place at temperatures between 250 • C and 300 • C [44][45][46][47], with residence times ranging between 10 and 60 min [48][49][50][51]. Torrefied biomass can be an attractive fuel for the power industry for combustion and co-firing [52][53][54][55], mainly due to increased grindability [56,57], which extends the time between renovations of the mill [58], and energy density [59][60][61][62].…”

Section: Introductionmentioning

confidence: 99%

Synergetic Co-Production of Beer Colouring Agent and Solid Fuel from Brewers’ Spent Grain in the Circular Economy Perspective

Jackowski¹,

Niedźwiecki²,

Mościcki³

et al. 2021

Sustainability

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Brewers’ Spent Grain is a by-product of the brewing process, with potential applications for energy purposes. This paper presents the results of an investigation aiming at valorization of this residue by torrefaction, making product for two purposes: a solid fuel that could be used for generation of heat for the brewery and a colouring agent that could replace colouring malt for the production of dark beers. Decreased consumption of malt for such purposes would have a positive influence on the sustainability of brewing. Torrefaction was performed at temperatures ranging between 180 °C and 300 °C, with a residence time between 20 and 60 min. For the most severe torrefaction conditions (300 °C, 60 min), the higher heating value of torrefied BSG reached 25 MJ/kg. However, the best beer colouring properties were achieved for mild torrefaction conditions, i.e., 180 °C for 60 min and 210 °C for 40 min, reaching European Brewery Convention colours of 145 and 159, respectively. From the solid fuel properties perspective, the improvements offered by torrefaction in such mild conditions were modest. Overall, the obtained results suggest some trade-off between the optimum colouring properties and optimum solid fuel properties that need to be considered when such dual-purpose torrefaction of BSG for brewery purposes is implemented.

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Impact of KCl impregnation on single particle combustion of wood and torrefied wood

Cited by 17 publications

References 38 publications

Experimental and modelling study on the influence of wood type, density, water content, and temperature on wood devolatilization

Experimental and modelling study on the influence of wood type, density, water content, and temperature on wood devolatilization

Predicting Biomass Char Yield from High Heating Rate Devolatilization Using Chemometrics

Synergetic Co-Production of Beer Colouring Agent and Solid Fuel from Brewers’ Spent Grain in the Circular Economy Perspective

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