AN ASSESSMENT ON ASH-RELATED ISSUES IN COMMERCIAL BIOMASS COMBUSTION SYSTEMS

Yıl 2024, Sayı: 716, 462 - 486, 03.10.2024

Anıl Badem , Hayati Olgun

Öz

One of the prominent technologies in biomass energy applications is commercial biomass combustion systems. While burning forest-derived biomass is a well-established and proven technology, the combustion of agricultural residues poses more challenges compared to forest-derived fuels. These challenges vary depending on factors such as the design of the combustion system, operational conditions, and the type, physical, and chemical properties of the biomass to be burned. Sintering, agglomeration, slagging, and corrosion are among the major issues that affect the regular and continuous operation of the combustion system, leading to unplanned shutdowns. This study investigates the applicability of common coal ash indices, widely used in the literature to predict these problems, to biomass ash for pre-analysis. Five different biomass feedstocks (reed canary grass, corn stalk, pine, poplar, and tree root) stored in open silos were sampled at two different time periods. Analyses of ash mineral content, chlorine content, sulfur content, and ash fusion temperatures were conducted, and various indices were calculated. Thus, changes in the problems related to biomass fuels depending on storage conditions will also be examined. As a result of the analyses and calculations, no significant relationship or prediction could be demonstrated among the existing indices due to the considerable differences between biomass ash and coal ash, as well as the heterogeneous nature of biomass feedstocks. The contradictory results highlight the necessity for further research and experimental tests under real conditions to establish or verify these indices. It is concluded that a more comprehensive evaluation, taking into account the heterogeneous structure and physicochemical characterization of solid biomass fuels, will be required based on actual combustion experiences.

Anahtar Kelimeler

Biomass, solid biofuels, fuel quality, fusibility, slagging, fouling, corrosion

TİCARİ BİYOKÜTLE YAKMA SİSTEMLERİNDE KÜL KAYNAKLI PROBLEMLER ÜZERİNE BİR DEĞERLENDİRME

Öz

Biyokütle enerji uygulamalarında kullanılan ticari teknolojilerin başında biyokütle yakma sistemleri gelmektedir. Orman kökenli biyokütlelerin ticari yakma sistemlerinde yakılması bilinen ve kanıtlamış bir teknoloji olmakla birlikte tarımsal atıklarının yakılması orman kökenli yakıtlara göre çok daha sorunlu olabilmektedir. Bu sorunlar; yakma sistemlerinin tasarımından, işletme koşullarına ve burada yakılacak biyokütlelerin türüne, fiziksel ve kimyasal özelliklerine bağlı olarak değişiklikler gösterebilmektedir. Bu sorunların başında, sistemin düzenli ve sürekli çalışmasını etkileyerek plansız duruşlara neden olan sinterleşme, aglomerasyon, cüruflaşma, korozyon gelmektedir. Bu çalışmada, bu sorunları önceden analiz etmek üzere literatürde yaygın olarak kullanılan kömür küllerinin indislerinin biyokütle külü üzerindeki uygulanabilirliği incelenmiştir. Açık alanda depolanan 5 farklı biyokütle hammaddesi (saz kamışı, mısır sapı, çam kapağı, kavak kapağı, ağaç kökü) silolarından iki farklı zaman diliminde alınan numunelerde kül mineral içeriği, klor içeriği, kükürt içeriği ve kül ergime sıcaklığı analizleri yapılarak indis hesaplamaları gerçekleştirilmiştir. Böylece biyokütle yakıtlarından kaynaklı sorunların depolama koşullarına bağlı değişimleri de incelenmiş olacaktır. Yapılan analizler ve hesaplamalar sonucunda biyokütle külünün kömürden önemli ölçüde farklı olması ve biyokütle hammaddelerinin heterojen yapısı nedeniyle kömüre özgü literatürde verilen indisler arasında herhangi bir ilişki veya öngörü net olarak ortaya konulamamıştır. Elde edilen çelişkili sonuçlar, bu indislerin oluşturulması veya doğrulanması için gerçek koşullar altında daha fazla araştırma ve deneysel testlerin gerekliliğini göstermektedir. Biyokütle yakıtlarının heterojen yapısı ve fizikokimyasal karakterizasyonu dikkate alınarak gerçek yanma deneyimlerine dayalı daha çok deneysel sonuçların birlikte değerlendirilmesine ihtiyaç duyulacağı görüşüne varılmıştır.

Anahtar Kelimeler

Biyokütle, katı biyoyakıtlar, yakıt kalitesi, eriyebilirlik, cüruflanma, kirlenme, korozyon

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