Exploration of potassium migration behavior in straw ashes under reducing atmosphere and its modification by additives

Yu, Bing; Li, Junguo; Wang, Zhiqing; Guo, Mingxi; Fan, Hongli; Wang, Tao; Fang, Yitian

doi:10.1016/j.renene.2019.07.141

Cited by 34 publications

(14 citation statements)

References 43 publications

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“…The effect was less pronounced in peach kernel ash, implying that the additive decreased the volatility of K at high temperatures by promoting ash-fixing reactions between K and aluminosilicate minerals. The positive effect of kaolin additive on K capture ability was reported in previous studies [7,23]. The chemical composition of lignite/biomass ash mixtures varied between that of component fuels.…”

Section: Influence Of Chemical Composition On Melting Behavior Of Ashessupporting

confidence: 71%

“…The ash-forming elements are generally dominated by silicon and potassium, the latter due to the use of fertilizers during crop cultivation. Such alkaline species, other alkaline earth metals, and problematic elements chlorine and sulfur may react with each other and/or with silica compounds through complex mechanisms to produce new chemicals and eutectics with low melting temperatures [7][8][9][10]. These compounds can cause ash slagging, fouling, and corrosion of heat exchange surfaces, thereby reducing the efficiency and availability of combustion systems and increasing the power cost [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Additives can capture problematic ash species by physical or chemical adsorption, or increase ash melting temperatures by altering the ash chemistry during combustion [7,11,16,17]. Kaolin has been proven highly effective in improving the slagging behavior of biomass fuels, such as straws [4,7,18], wood pellets [3,9], and olive cake [9], by decreasing the initial deformation temperature of ashes between 200 and 240 °C. Similarly, Ca-based additives and coal fly ash have been found to mitigate the melting of straws [4,9,16], herbaceous biomass [6], wood, and olive cake [9,16] by lowering the initial deformation temperature of ashes between 40-and 140 °C and 55-and 90 °C, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Mineral Additives on Fusion Behavior of Agricultural Residue Ashes during Combustion or Co-combustion with Lignite

Vamvuka¹,

Deli²,

Stratakis³

2021

JEPT

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In this work, the ash fusibility behaviour of selected agricultural residues and their blends with lignite was studied, by carrying out chemical, mineralogical, fusibility and thermogravimetric analyses and calculating slagging/fouling indicators for predicting deposition tendencies in boilers. Two additives, bauxite, and clinochlore, were used at varying amounts to reduce ash melting, followed by examining their anti-fusion mechanisms. Initial deformation and softening temperatures of biomass materials were low for combustion processes operating above 900 °C due to their high concentration in K, Na, and P compounds. When the additives were mixed with raw fuels or lignite/biomass blends, the initial deformation of ashes started at temperatures up to 340 °C higher, whereas the fluid temperature in most cases exceeded 1500 °C. Bauxite was more effective than clinochlore. The positive impact of additives was attributed to the mineralogical transformations during ashing to phases with a high melting point through reactions with K, Na-bearing minerals, or CaO of fuel ashes.

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Section: Influence Of Chemical Composition On Melting Behavior Of Ashessupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Mineral Additives on Fusion Behavior of Agricultural Residue Ashes during Combustion or Co-combustion with Lignite

Vamvuka¹,

Deli²,

Stratakis³

2021

JEPT

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show abstract

“…The volatility of the alkaline elements (Na and K) was <8% during ashing temperatures in 500–600 °C; 57 the volatility of relatively low alkaline element contents in raw materials could be neglected below 600 °C. 1 The laboratory ashes of the three LRCs, MS, and their mixtures (MS proportions of 3, 6, 9, 12, and 15% were mixed with each of the three LRCs) were prepared based on ASTM E1755-01 standards. The samples were placed in an SX2-8-16ASP muffle furnace (Kewei Co., Beijing, China), which first was increased to 250 °C at 10 °C/min and maintained at that temperature for 30 min.…”

Section: Methodsmentioning

confidence: 99%

Understanding Ash Sintering Variation Behaviors of Low-Rank Coals with Municipal Sludge Addition Based on Mineral Interactions

Yang

Wang²,

Liu³

et al. 2022

ACS Omega

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Co-gasification with coal provides an economically viable way to use sludge. To investigate the effect of municipal sludge (MS) on the sintering behaviors of low-rank coals (LRCs) and their modification mechanisms, the initial sintering temperature ( T s ) of three LRCs and their mixtures with MS addition were tested by a T s analyzer, an X-ray diffractometer, and FactSage calculation. The results show that the T s values of Xiaolongtan coal (XLT), Xiangyuan coal (XY), and Daliuta coal (DLT) all increase with MS addition. The 9–12% MS mass ratio is suitable during LRC fluidized-bed gasification to mitigate ash-related issues. The T s is closely related to the liquid-phase content or the transmissions of microparticles (e.g., atoms and ions) or blank spots during heating, while the ash fusion temperatures (AFTs) are mainly determined by acid/base ratios. The T s values of high-Fe XLT and XY mixed ashes increased gradually with increasing MS proportion because the sintering mechanisms transferred from liquid phase to solid phase, while for relatively high-Mg DLT ashes, the T s values increased with increasing MS proportions, which might result from the formations of high-melting-point minerals (e.g., Ca 3 (PO 4 ) 2 and Mg 2 SiO 4 ). The results deepen the understanding of ash sintering behaviors and provide references to alleviate ash-related issues during gasification.

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Evaluation on thermal pyrolysis of biomass straw waste: Focusing aspects of products yields, syngas emissions and solid products characterization

Yao,

Zhou,

et al. 2024

Asia-Pacific J Chem Eng

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In this study, a systematic and quantitative investigation of the pyrolysis characteristics of biomass was conducted in a fixed‐bed tubular reactor, and the influence of pyrolysis temperature on product yields, gas emission characteristics, and syngas compositions as well as physicochemical characterization of resulting solids (i.e., char/ash morphologies, mineral transformations, and elemental compositions) was explored in detail. The pyrolysis experiments were performed under N2, and the resulting solid characterization was detected by XRD, SEM, and EDX. The results indicated that with increasing the pyrolysis temperature from 400 to 800°C, the gaseous product yields increased from 54.9% to 66.7%, while the solid product yield showed a reverse trend, varying within 27.7%–40.5%. Meanwhile, the volume fraction of H2 in syngas increased from 7% to 33%, while the CO2 presented an opposite trend, suggesting that high temperature favored H2 formation and inhibited CO2 formation. On the whole, the CO and CO2 emissions were prior to CH4, H2, and CnHm in sequence. A large amount of sylvite (KCl), quartz (SiO2), dolomite (CaMg(CO3)2), and pyroxene (CaMgSi2O6) in the resulting solids were identified in crystal phases. Higher pyrolysis temperature had a significant influence on solid microstructures, resulting in a relatively higher slagging tendency due to low melting eutectics containing K‐rich and Ca‐rich minerals.

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Exploration of potassium migration behavior in straw ashes under reducing atmosphere and its modification by additives

Cited by 34 publications

References 43 publications

Effect of Mineral Additives on Fusion Behavior of Agricultural Residue Ashes during Combustion or Co-combustion with Lignite

Effect of Mineral Additives on Fusion Behavior of Agricultural Residue Ashes during Combustion or Co-combustion with Lignite

Understanding Ash Sintering Variation Behaviors of Low-Rank Coals with Municipal Sludge Addition Based on Mineral Interactions

Evaluation on thermal pyrolysis of biomass straw waste: Focusing aspects of products yields, syngas emissions and solid products characterization

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