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Journals / Mühendis ve Makina / 2026 / Cilt: 67 Sayı: 723

Determination of Aspect Ratio and Excess Air Coefficient to Shorten Start-up Time at Small Size Fluidized Bed Boiler

Düşük kapasiteli akışkan yataklı kazanlarda hızlı start-up yapabilmek için uygun hava fazlalık katsayısının ve yatak en/boy oranının belirlenmesi

Karani Kurtuluş(SULEYMAN DEMIREL UNIVERSITY)0000-0002-2608-3065
Pages
289–309
Publication Date
2026-06-30
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

The analysis results show start-up time decreases (up to 32%) as the bed aspect ratio decreases.

📌 3 Key Takeaways

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Objective & Hypothesis:Energy production from clean and renewable sources has gained prominence in recent years.
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Key Findings & Data:Then, CFD analyses were carried out for different bed aspect ratios (0.55, 0.65, and 0.90) and different coefficients of burner excess air (1.2, 1.4, and 1.6).
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Conclusion & Impact:The analysis results show start-up time decreases (up to 32%) as the bed aspect ratio decreases.
🔬Design:Araştırma Makalesi
📍Scope:Comprehensive Sample
⚙️Variables:Start-up · Kum ısıtma · Akışkan yatak

Abstract

Energy production from clean and renewable sources has gained prominence in recent years. The use of fluidized bed boilers in industrial applications is increasing due to their high combustion efficiency and low NOx emission. Fluidized beds are suitable for coal and biomass combustion and other gasification applications. Therefore, these systems are expected to become more widespread. Although they are widely used in industry, fluidized bed combustion systems start-up processes are generally based on experience. Start-up is an essential process in the operation of small size fluidized beds. Shorter start-up times are desired, especially in systems requiring frequent start-ups. This study investigated the effect of the height of static bed material and the coefficient of burner excess air on start-up time. Therefore, a bench-scale experimental setup was established. CFD analysis was verified with temperature data measured by the testing apparatus. Then, CFD analyses were carried out for different bed aspect ratios (0.55, 0.65, and 0.90) and different coefficients of burner excess air (1.2, 1.4, and 1.6). The analysis results show start-up time decreases (up to 32%) as the bed aspect ratio decreases. On the other hand, as the excess air coefficient increases, the start-up time increases (up to 44%). In addition, in the start-up process, excess air coefficient 1.4 and then 1.2 were proposed for a shorter start-up time with an aspect ratio of 0.9.

Özet

Temiz ve yenilenebilir enerji üretimi her geçen yıl önemini arttırmaktadır. Akışkan yataklı kazanlar endüstride kullanımları yüksek yakma verimi ve düşük NOx emisyonlarından dolayı giderek artmaktadır. Bununla birlikte akışkan yataklı kazanlar kömür ve biyokütle yakabildikleri gibi gazlaştırma prosesleri için de uygundur. Bundan dolayı bu sistemlerin ileride daha da yaygınlaşacağı beklenmektedir. Piyasada yaygın olarak kullanılmalarına rağmen bu sistemlerde kalkış (start-up) prosesi daha çok tecrübeye bağlıdır. Küçük kapasiteli akışkan yataklı sistemler için start-up prosesi oldukça önemlidir. Özellikle sık start-up yapan sistemler için kısa sürede hızlı start-up istenmektedir. Bu çalışmada statik yatak yüksekliği ve hava fazlalık katsayısının start-up prosesine olan etkisi araştırılmıştır. Bunun için laboratuvar ölçekli test düzeneği kurulmuştur. Deney düzeneğinden ölçülen sıcaklık verileri ile HAD analizlerinden bulunan değerler karşılaştırılarak doğrulama yapılmıştır. Daha sonra HAD analizleri yatak en/boy oranı 0.55, 0,65, 0,90 ve hava fazlalık katsayısı 1.2, 1.4 ve 1.6 için yürütülmüştür. Analizlere göre yatak en/boy oranı azaldıkça start-up süresinin %32’ ye kadar düştüğü görülmüştür. Öte yandan hava fazlalık katsayısı arttıkça start-up süresinin %44’ e kadar arttığı bulunmuştur. Ek olarak küçük kapasiteli akışkan yatakta en boy oranı 0.9’da en uygun start-up süresi elde edebilmek için başlangıçta hava fazlalık katsayısı 1.4 daha sonra 1.2 olarak uygulanması önerilmiştir.

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Cite This Article

Kurtuluş, K. (2026). Determination of Aspect Ratio and Excess Air Coefficient to Shorten Start-up Time at Small Size Fluidized Bed Boiler. Mühendis ve Makina, Cilt: 67 Sayı: 723, 289–309. https://doi.org/10.46399/muhendismakina.1793835

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