SİRKÜLASYONLU BİR AKIŞKAN YATAKLI YAKICIDA İŞLETME PARAMETRELERİNİN SO2 EMİSYONU ÜZERİNDEKİ ETKİLERİ

Öz

Çevresel korunma göz önüne alındığında, güç santrallerinde SO2 emisyonunun indirgenmesi ana konulardan biridir. Kömürün sirkülasyonlu akışkan yatak (SAY) yakma teknoloji ile yakılmasının en önemli avantajlarından birisi de genellikle kalsine olmamış kireçtaşı (CaCO3) gibi sorbentlerin eklenmesiyle doğal SO2 tutma kabiliyetidir. Bu teorik çalışmada, sorbent tane çapı, Ca/S mol oranı ve yatak işletme hızı gibi işletme parametrelerinin SO2 emisyonu üzerindeki etkileri; daha önce SAY yakıcılar için geliştirilmiş olan dinamik model kullanılarak tahmin edilmiştir. Modelde reaksiyona girmemiş büzülen tanecik modeli kükürt indirgenmesine adapte edilmiştir. Bu çalışma sonucunda; yatak işletme hızının SO2 emisyonu üzerinde pozitif bir etkiye sahip olduğu, ikincil hava kullanmanın yatak içerisindeki sülfür dağılımı ve konsantresi üzerinde güçlü bir etkiye sahip olduğu ve beslenen kireçtaşının içeriğinin yüksek oranda toz içermesi durumunda yatak içerisinde kükürt indirgemesini arttırdığı görülmüştür.

Anahtar Kelimeler

• Sirkülasyonlu akışkan yatak, kömür yanması, modelleme, SO2 emisyonu

EFFECTS OF OPERATIONAL PARAMETERS ON SO2 EMISSION IN A CIRCULATING FLUIDIZED BED COMBUSTOR

Öz

Reducing SO2 emission from power plants is one of the main issues for the environmental protection. One of the advantages of the CFB combustion technology of coal is in situ SO2 capture by added sorbents, usually uncalcined limestone (CaCO3). In this theoretical study effects of operational parameters such as sorbent particle diameter, Ca/S molar ratio and superficial velocity on SO2 emission have been estimated using a previously developed dynamic 2D model for CFBCs. In the model, the unreacted shrinking core model has been adopted for desulphurization. As a results of this study; it is observed that operational bed velocity has positive effect on SO2 emission. Air-staging strongly influences the concentration and distribution of sulphur compounds in the combustion chamber of fluidized beds. Feeding limestone with high proportion of fines into the combustor causes high sulphur retentions.

Anahtar Kelimeler

• Circulating fluidized bed, coal combustion, modeling, SO2 emission

Kaynakça

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