A Comprehensive Review of Ash Issues in Oxyfuel Combustion of Coal and Biomass: Mineral Matter Transformation, Ash Formation, and Deposition

Yu, Dunxi; Yu, Xin; Wu, Jianhui; Han, Jingkun; Liu, Fangqi; Pan, Haoxiang

doi:10.1021/acs.energyfuels.1c02231

Cited by 16 publications

(8 citation statements)

References 116 publications

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“…27,28 Moreover, the substitution of carbon dioxide instead of nitrogen in this technology helps to prevent the emission of NO x as an undesirable product of air combustion technology. 29 Yushiie et al 30 conducted experimental and numerical analysis on the effect of NO x formation in the oxyfuel combustion technology, and their results confirmed that NO x emissions under CO 2 −O 2 conditions were lower than those under "air" conditions. Oxyfuel combustion has been approved in several studies, by using different types of fuels, it can reduce NOx emissions.…”

Section: Monoethanolamine (Mea) Is a Useful Solvent In Industrialmentioning

confidence: 88%

Oxyfuel Combustion Makes Carbon Capture More Efficient

Talei,

Fozer,

Varbanov

et al. 2024

ACS Omega

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Fossil energy carriers cannot be totally replaced, especially if nuclear power stations are stopped and renewable energy is not available. To fulfill emission regulations, however, points such as emission sources should be addressed. Besides desulfurization, carbon capture and utilization have become increasingly important engineering activities. Oxyfuel technologies offer new options to reduce greenhouse gas emissions; however, the use of clean oxygen instead of air can be dangerous in the case of certain existing technologies. To replace the inert effect of nitrogen, carbon dioxide is mixed with oxygen gas in the case of such air combustion processes. In this work, the features of carbon capture in five different flue gases of air combustion and such oxyfuel combustion where additional carbon dioxide is mixed with clean oxygen are studied and compared. The five different flue gases originate from the gas-fired power plant, coal-fired power plant, coal-fired combined heat and power plant, the aluminum production industry, and the cement manufacturing industry. Monoethanolamine, which is an industrially preferred solvent for carbon dioxide capture from gas streams at low pressures, is selected as an absorbent, and the same amount of carbon dioxide is captured; that is, always that amount of carbon dioxide is captured, which is the result of the fossil combustion process. ASPEN Plus is used for mathematical modeling. The results show that the oxyfuel combustion cases need significantly less energy, especially at high carbon dioxide removal rates, e.g., higher than 90%, than that of the air combustion cases. The savings can even be as high as 84%. Moreover, 100% carbon capture was also be completed. This finding can be due to the fact that in the oxyfuel combustion cases, the carbon dioxide concentration is much higher than that of the air combustion cases because of the inert carbon dioxide and that higher carbon dioxide concentration results in a higher driving force for the mass transfer. The oxyfuel combustion processes also show another advantage over the air combustion processes since no nitrogen oxides are produced in the combustion process.

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Section: Monoethanolamine (Mea) Is a Useful Solvent In Industrialmentioning

confidence: 88%

Oxyfuel Combustion Makes Carbon Capture More Efficient

Talei,

Fozer,

Varbanov

et al. 2024

ACS Omega

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“…During pyrolysis, the majority of Cl is released into volatiles in the forms of HCl and/or chloromethane (CH 3 Cl) due to the interactions between Cl and biomass organic compounds, − with ∼28% being retained in the biochar. This suggests another advantage of using biochar as a co-firing fuel because Cl-related operational problems (e.g., ash deposition and particulate matter emission) , can be largely mitigated.…”

Section: Experimental Sectionmentioning

confidence: 99%

Characterization of Ashes from Co-Firing Biochar with Coal under Pulverized-Fuel Conditions

Chen

Gao

2022

ACS Eng. Au

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This contribution presents results on the systematic characterization of the ashes from the co-combustion of biochar or its corresponding raw biomass and coal under pulverized-fuel conditions. A mallee bark (75–90 μm) was subjected to fast pyrolysis at 500 °C to prepare a biochar. The bark and the biochar were then co-fired with a Collie coal of identical size fraction in a laboratory-scale drop-tube furnace at 1400 °C in air, with biomass/biochar shares of 5, 20, and 40% expressed based on lower heating values. The produced ashes were collected using a cyclone and systematically characterized. The results demonstrate that the morphology of the ashes from the bark and the biochar is of irregular shape, whereas the coal ash particles are round. The ash particles follow a unimodal distribution, with an area-equivalent mode diameter of ∼5–12 μm, except for the ash from the bark combustion that also shows two larger peaks at ∼65 and ∼95 μm. The compositions of the ashes from the bark and the biochar are similar, both rich in Ca and Mg, whereas the coal ash contains dominantly Si, Al, Fe, and Ca. Under identical co-firing ratios, replacing the bark with the biochar results in higher contents of Mg and Ca in the ashes because of the enrichment of these elements in the biochar. The major minerals identified in the coal ash include mullite, quartz, and hematite, and those in the bark ash and the biochar ash are portlandite, magnesite, calcite, and lime. Up to ∼56% of Na, ∼41% of K, ∼56% of Mg, and ∼69% of Ca in the ashes can be recycled via water leaching, with negligible environmental concerns. These data are important in developing suitable strategies for the utilization and management of ashes derived from the co-combustion of biochar (or biomass) and coal.

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“…An extensive body of research has been dedicated to investigating ash deposition mechanisms, which are well-understood to include inertial impaction, eddy impaction, thermophoresis, condensation, and chemical reactions . Numerous review articles, each focusing on distinct research interests and published across different eras, have enriched our understanding of these processes. − For instance, Kleinhans et al comprehensively analyzed the behaviors of ash particles sticking and rebounding, shedding light on their intricacies. Niu et al compiled key issues concerning ash deposition during biomass combustion, with a particular emphasis on the role of alkali species.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, Cai et al critically reviewed the progression of ash deposition numerical simulation, encompassing aspects such as particle combustion and sticking, rebound, and removal behaviors. Yu et al offered a detailed review of ash deposition behavior in oxy-fuel combustion, concentrating on experimental results.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, Cai et al 18 critically reviewed the progression of ash deposition numerical simulation, encompassing aspects such as particle combustion and sticking, rebound, and removal behaviors. Yu et al 11 offered a detailed review of ash deposition behavior in oxy-fuel combustion, concentrating on experimental results. Currently, it is recognized that ash deposits can be categorized into "inside" and "outside" portions, each corresponding to different formation stages.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved Comprehensive Mechanism for Initial Deposit Formation: The Role of Thermophoresis and Glue Effect in Solid Fuel Combustion

Wang,

Zhou,

et al. 2023

Energy Fuels

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Ash deposition during solid fuel combustion presents significant challenges for the efficiency and longevity of thermal power plants. Understanding the dynamics of this process is, therefore, of critical importance. This study delves into the complex mechanisms involved with a focus on the formation of the initial deposit layer. By highlighting the pivotal role of submicrometer particles in this process, we expand upon our one-decade long studies on this topic and explore a diverse range of fuel types, air-and oxyfiring conditions, and additive tests, with a total of 47 experimental results. First, this work suggests that the yield of submicron (PM 1 ) particles, expressed as a percentage, is a more effective predictor of initial deposit layer formation than its concentration in g/m 3 . Second, we acknowledge the influence of mainstream velocity and temperature gradients on deposition, leading us to introduce a new thermophoresis correction factor. This addresses the probability of submicrometer particles impacting the wall. Furthermore, we examine the influence of PM 1 composition, proposing a glue effect correction factor defined by an empirical value relating to chlorine contents. In conclusion, this study presents an enhanced comprehensive understanding of the initial ash deposition process during solid fuel combustion. This improvement is largely attributed to the integration of a physical model with machine learning techniques. Although the glue effect correction factor requires further investigation, this research offers significant insight into the initial deposition process. It thus charts a course for more efficient strategies to mitigate ash deposition in thermal power plants in the future.

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A Comprehensive Review of Ash Issues in Oxyfuel Combustion of Coal and Biomass: Mineral Matter Transformation, Ash Formation, and Deposition

Cited by 16 publications

References 116 publications

Oxyfuel Combustion Makes Carbon Capture More Efficient

Oxyfuel Combustion Makes Carbon Capture More Efficient

Characterization of Ashes from Co-Firing Biochar with Coal under Pulverized-Fuel Conditions

Improved Comprehensive Mechanism for Initial Deposit Formation: The Role of Thermophoresis and Glue Effect in Solid Fuel Combustion

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