A comprehensive review on efficient utilization methods of High-alkali coals combustion in boilers

Tang, Congwei; Pan, Weiguo; Zhang, Jiakai; Wang, Wenhuan; Sun, Xiaoli

doi:10.1016/j.fuel.2022.123269

Cited by 45 publications

(21 citation statements)

References 191 publications

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“…Solid-fuel combustion plants that utilize solid fuels, such as coal, biomass, and sewage sludge, play a pivotal role in diminishing waste volume and producing electrical energy for everyday use. However, in these plants, ash particles formed from the unburnable portion of the fuel are deposited onto the heat exchanger and the inner lining of the duct, leading to heat-transfer obstructions, pipeline obstructions, and other operational inefficiencies and resulting in diminished operating productivity. − Thus, managing ash particle adhesion in high-temperature environments is critical to ensuring steady and highly effective plant operation. Alkali metals in ash can react with SiO 2 and Al 2 O 3 , which are the main components of ash and bed materials in a fluidized bed furnace. , As a result, compounds with a melting point lower than those of SiO 2 and Al 2 O 3 form and subsequently melt at the operating temperatures.…”

Section: Introductionmentioning

confidence: 99%

Role of Al-Based Additives in Controlling Ash Adhesion

Okuizumi,

Horiguchi,

Kamiya

et al. 2024

Energy Fuels

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In combustion plants, ash particles adhere to the plant walls because of liquid bridging induced by the melting of alkali-metal compounds. The presence of adhered ash particles can hinder the efficient and stable operation of the plant. Therefore, adopting appropriate adhesion control methods that suit the combustion conditions is critical. Additives, which are one method to deal with ash adhesion, increase the slag formation temperature and prevent the formation of liquid bridges by changing the composition of the ash. However, with the recent expansion of biomass utilization, various types of ash are generated, and additives that are effective irrespective of the ash composition are desirable. This study aims to investigate the effect of three different Al salts on adhesion reduction using synthetic ashes that exhibit high-temperature adhesion caused by the melting of Na and K components. The study revealed the influence of the counteranions of the Al salts on the adhesion of ash particles. The results indicate that the pyrolysis temperature for the Al salts and the reactivity of the heat treatment intermediates play critical roles in controlling adhesion.

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Section: Introductionmentioning

confidence: 99%

Role of Al-Based Additives in Controlling Ash Adhesion

Okuizumi,

Horiguchi,

Kamiya

et al. 2024

Energy Fuels

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“… 6 , 7 Post-combustion, control methods generally involve periodic cleaning of the slag body with a slag removal device. 8 Among the measures, the leaching method is simple and effective in reducing the AAEM content in AOSW. This provides a fundamental solution to the problem of fouling and slagging in the combustion process and has broad utilization prospects.…”

Section: Introductionmentioning

confidence: 99%

“…Fouling and slagging problems are mitigated by various measures before, during, or after combustion. Precombustion pretreatment is to remove AAEMs in advance by leaching, and during combustion, controls use additives to reduce the proportion of AAEMs in ash to inhibit slagging. , Post-combustion, control methods generally involve periodic cleaning of the slag body with a slag removal device . Among the measures, the leaching method is simple and effective in reducing the AAEM content in AOSW.…”

Section: Introductionmentioning

confidence: 99%

Flue Gas-Enhanced Water Leaching: AAEM Removal from Agricultural Organic Solid Waste and Fouling and Slagging Suppression during Its Combustion

Wang

Xiong

et al. 2023

ACS Omega

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Alkali and alkaline earth metals (AAEMs) in agricultural organic solid waste (AOSW) contribute to the fouling and slagging during its combustion. In this study, a novel flue gas-enhanced water leaching (FG-WL) method using flue gas as the heat and CO2 source was proposed for effective AAEM removal from AOSW before combustion. The removal rate of AAEMs by FG-WL was significantly superior to that by conventional water leaching (WL) under the same pretreatment conditions. Furthermore, FG-WL also obviously reduced the release of AAEMs, S, and Cl during AOSW combustion. The ash fusion temperatures of the FG-WL-treated AOSW was higher than that of WL. The fouling and slagging tendency of AOSW greatly decreased through FG-WL treatment. Thus, FG-WL is a simple and feasible method for AAEM removal from AOSW and suppressing fouling and slagging during its combustion. Besides, it also provides a new pathway for the resource utilization of power plant flue gas.

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“…Besides, it can result in metal corrosion, serious blockage of the flue gas flow channel, and so on 20 . In brief, the existence of low‐temperature fouling in the tail flue will result in lower boiler efficiency and lead to an adverse effect on the normal and safe operation of coal‐fired power station boilers 21 …”

Section: Introductionmentioning

confidence: 99%

“…20 In brief, the existence of lowtemperature fouling in the tail flue will result in lower boiler efficiency and lead to an adverse effect on the normal and safe operation of coal-fired power station boilers. 21 At present, extensive research such as the growth characteristic, mineralogy, and chemical composition of the ABS-bearing low-temperature fouling has been investigated. Chen et al [22][23][24] experimentally investigated the fouling characteristics of a rotary air preheater, a flue gas cooler, and a low-pressure economizer by analyzing the fouling samples.…”

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confidence: 99%

Experimental investigation of the strength characteristics of low‐temperature fouling containing ammonium bisulfate in boilers

Tang

Zhang

Wang

et al. 2022

Asia-Pacific J Chem Eng

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Low-temperature fouling is a severe problem in the heat recovery devices of coal-fired boilers; it is mainly caused by the condensation of ammonium bisulfate (ABS, NH 4 HSO 4 ) and is usually challenging to remove with soot-blowing equipment. This study investigates the strength of low-temperature fouling containing ABS, which is an essential indicator in soot blowing. The ash sample containing ABS with three different mass ratios was heated in a drop tube furnace (DTF) at several selected temperature conditions for different times.The compressive strength of ash blocks after heating was measured, and the energy-dispersive X-ray spectrometry (EDX) and scanning electron microscope (SEM) were used to clarify the relationship between ABS content with fouling strength. The results show that the higher content of ABS means higher fouling strength. The fouling strength could decrease by heating the fouling under the flue gas temperature is 350 C or more, and a higher heating temperature could result in lower strength of the fouling. To reduce the strength and maximize the removal of fouling effectively, taking into account the economy, the recommended heating condition is to heat the fouling for 5-20 min at a minimum temperature of 350 C.

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A comprehensive review on efficient utilization methods of High-alkali coals combustion in boilers

Cited by 45 publications

References 191 publications

Role of Al-Based Additives in Controlling Ash Adhesion

Role of Al-Based Additives in Controlling Ash Adhesion

Flue Gas-Enhanced Water Leaching: AAEM Removal from Agricultural Organic Solid Waste and Fouling and Slagging Suppression during Its Combustion

Experimental investigation of the strength characteristics of low‐temperature fouling containing ammonium bisulfate in boilers

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