Modeling of unburned carbon in fly ash and importance of size parameters

Bilen, Mehmet; Kizgut, Sait

doi:10.1016/j.fuproc.2015.10.039

Cited by 21 publications

(5 citation statements)

References 21 publications

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“…Then, the volatile substances evolve rapidly, and the fixed carbon begins to burn. Due to the influence of atmosphere and particle size, the combustion of the pulverized coal may not completely end before it reaches the pellet layer, which leads to a small amount of residual carbon in the combustion products [55,56]. Previous studies show that the lower the combustion efficiency of pulverized coal injection, the higher the residual carbon content in the combustion products [51].…”

Section: Effect Of Pulverized Coal Combustion Efficiencymentioning

confidence: 99%

The Deposit Formation Mechanism in Coal-Fired Rotary Kiln for Iron Ore Pellet Production: A Review

Wang

Guo

et al. 2021

Crystals

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The deposit-forming problem is one of the main bottlenecks restricting the yield and production benefit of iron ore pellets produced by coal-fired rotary kilns. In order to implement measures to ensure the efficient production of pellets by coal-fired rotary kilns, the mechanism and influencing factors on the deposit formation were reviewed. The pellet powder and coal ash come together to form the material base of the deposit. Meanwhile, the local reducing atmosphere caused by the continued combustion of residual carbon increases the FeO content, resulting in the formation of low-melting-point silicates. Moreover, alkali metal elements in coal ash can also promote liquid phase formation to cause serious deposit aggregation problems. During high-temperature roasting, the liquid phase corrodes the surface of the refractory brick to form the initial deposit, whereafter, it binds the pellet powder and coal ash from the material layer, which causes the deposit to accumulate continuously. The deposit formation of coal-fired rotary kilns is the result of interaction between many factors, which includes the quality of the green pellets, the composition of coal ash, the combustion efficiency of pulverized coal, roasting temperature, FeO content and alkali metal input. Finally, it is recommended that some measures to mitigate deposit formation can be adopted, such as increasing the compression strength of preheated pellets, choosing high-quality raw materials with low alkali metals, improving the combustion of pulverized coal.

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Section: Effect Of Pulverized Coal Combustion Efficiencymentioning

confidence: 99%

The Deposit Formation Mechanism in Coal-Fired Rotary Kiln for Iron Ore Pellet Production: A Review

Wang

Guo

et al. 2021

Crystals

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“…Ünite 2 için 9 vardiya boyunca her bir boyut parametresinin (D10. D50, D90, D32, D43) yanmamış karbon (%) miktarıyla ilişkisi [15] Şekil 9. Ünite 3 için 9 vardiya boyunca her bir boyut parametresinin (D10.…”

Section: Değirmen çıKışlarından Alınan Kömür öRneği çAlışmalarıunclassified

Termik Santral Küllerinde Yanmamış Karbonun Pulverize Kömür Boyut Dağılımı ve Uçucu Madde İçeriği ile İlişkisi

Bilen

Yılmaz

2020

Bitlis Eren Üniversitesi Fen Bilimleri Dergisi

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ÖzBu çalışmada, iki termik santral özelinde uçucu küller yanmamış karbon açısından incelenmiş ve elde edilen analiz sonuçları kömürün kısa analiz sonuçlarıyla ve kömürün öğütülme sonrası boyut parametreleriyle karşılaştırılmıştır. İncelenen ilk santral için, yanma kazanının aynı şartlar altında farklı kömür örnekleriyle çalıştığı bir süreç incelenirse ve bu süreçte küllerde farklı değerlerde yanmamış karbon tespit edilirse, bunun nedeninin daha çok kömüre ait nedenler olduğu düşünülebilir. Bu çalışmada, iki farklı santral değerlendirilmiş olup, 17 farklı uçucu madde içeriği olan kömür kullanan birinci santralde gözlemlenen 17 farklı yanmamış karbon değerinin ilişkisi kurulmuş ve sonuçlar kömürün uçucu madde içeriğinin yanmamış karbon üzerinde oldukça etkili olduğunu göstermiştir. İkinci santralde ise pulverize kömür örneklerinin boyut dağılımları incelenmiş ve boyut parametreleriyle yanmamış karbon arasındaki ilişkiler belirlenmiştir. Kömür boyut dağılımına ait D32 boyut parametresinin yanmamış karbon ile ilişkisinin anlamlı olduğu sonucuna varılmıştır.

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“…Online measurement based on Infrared emissions was developed by Bonanno et al [22]. Sathyanathan and Mohammad [23], Bilen and Kizgut [24] proposed the use of empirical relations for the prediction of UC in bottom and fly ash. Pallarés et al [25] predicted UC in fly ash based on Artificial Neural Network (ANN) system.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Online Measurement of Unburned Carbon in Pulverized Fuel Boilers by Thermal Oxidation of Ash

2019

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The unburned carbon (UC) in the ash in Indian power plants is presently measured offline by manually collecting the samples and analyzing it by loss on ignition or thermogravimetric analysis methods. The manual collection and offline analysis of samples take 6-8 h. By this time, the existing operating conditions of the boiler may be different from the conditions when the samples were collected. The combustion optimization and corrective maintenance activities can be performed immediately by plant operation and maintenance team if the UC values are available online along with furnace flame intensity and the percentage of CO in flue gases at economizer outlet. The presence of high amounts of the UC in ash decreases the boiler efficiency and reduces the utilization of ash in cement industries. In this paper, 20 ash samples were collected from five Indian thermal power plants of range 150-500 MW. An experimental setup has been developed for the measurement of the UC using the percentages of CO 2 and CO obtained by thermal oxidation of ash. The experimental results were compared with the laboratory results. The maximum deviation between experimental and laboratory results was within the range of ± 0.30. The percentages of the UC is more accurate when CO 2 and CO both are considered in comparison to the present existing online measurement based on CO 2 only.

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Modeling of unburned carbon in fly ash and importance of size parameters

Cited by 21 publications

References 21 publications

The Deposit Formation Mechanism in Coal-Fired Rotary Kiln for Iron Ore Pellet Production: A Review

The Deposit Formation Mechanism in Coal-Fired Rotary Kiln for Iron Ore Pellet Production: A Review

Termik Santral Küllerinde Yanmamış Karbonun Pulverize Kömür Boyut Dağılımı ve Uçucu Madde İçeriği ile İlişkisi

Experimental Study on Online Measurement of Unburned Carbon in Pulverized Fuel Boilers by Thermal Oxidation of Ash

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