Ay çekirdeği küspesinden biyokömür eldesi ve gazlaştırılması
Küçük Resim Yok
Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Yenilenebilir enerji kaynağı olarak biyokütle kullanılması son yıllarda yaygınlaşmıştır. Büyük ölçekli güç sistemlerinde ekonomik olarak biyokütleyi kullanabilmek için fiziksel ve kimyasal özelliklerinin iyileştirilmesi gereklidir. Bu özellikler termal bir ön işlem olan biyokömürleştirme(torrefaction) ile geliştirilebilir. Biyokömürleştirme işlemi sonunda enerji içeriği yüksek katı yakıt (biyokömür) elde edilir. Sıcaklık dışında bekletme süresi, ısıtma hızı, parçacık boyutu ve biyokütlenin yapısı gibi biyokömürleştirme işlemini etkileyen birçok parametre bulunmaktadır. Bu tez çalışmasının ilk kısmında, ay çekirdeği küspesinden paslanmaz çelikten yapılmış 1 litre hacme sahip sabit yataklı dikey reaktörde biyokömür eldesi için parametrik çalışmalar yapılmıştır. Deneyler üç biyokömürleştirme sıcaklığında (250, 300, 350 oC) ve iki bekletme süresinde (10 dk - 30 dk) gerçekleştirilmiştir. % 47'lik kütle verimi ve % 60'lık enerji verimi ile 23940 kJ/kg ısıl değere ulaşılan 300 oC - 30 dk işletme koşulları optimum proses koşulu olarak belirlenmiştir. Sıcaklık artarken kütle ve enerji veriminin düştüğü; buna karşılık ısıl değerin ve enerji yoğunluğunun arttığı görülmüştür. Ayrıca sıcaklık, bekletme süresine göre daha etkili olmuştur. Optimum koşulların belirlenmesinin ardından, pilot ölçekli sürekli biyokömürleştirme sisteminde bu optimum koşullara göre biyokömür üretimine geçilmiştir. Her iki sistemden çıkan biyokömürün analizleri yapılmış ve benzer özellikleri taşıdıkları gözlenmiştir. Tezin ikinci kısmında, laboratuvar ölçekli su buharı gazlaştırma sisteminde elde edilen biyokömürlerin linyitle birlikte gazlaştırılabilirliği incelenmiştir. Deneyler iki farklı oranda biyokömür katkısı ile (1:4, 1:1) ve 1:1 oranında biyokütle katkısı ile gerçekleştirilmiştir. Karşılaştırma yapabilmek için 500 oC'de pirolizle elde edilen katı ürün de iki farklı oranda (1:4, 1:1) linyitle karıştırılarak gazlaştırılmıştır. Hidrojen içeriğini arttırmada inorganik içeriğin yanı sıra, uçucuların etkisinin de büyük olduğu ve biyokömürleştirme işleminin yakıt karakteristiğini geliştirerek hidrojen verimini artırdığı sonucuna varılmıştır
The use of biomass as a renewable fuel has become more interest in the recent years. In order to use biomass economically in large-scale power systems needs to increase its chemical and physical properties. These properties may be improved by torrefaction, which is thermally pre-processing. Torrefaction is an important pretreatment process around 200-350 oC to provide energy enriched solid fuel named as bio coal. In addition to temperature, there are many parameters that affect the torrefaction process. These are residence time and heating rate, as well as raw material particle size and composition. In the first part of this thesis, bio coal was produced from sunflower seed cake in stainless-steel 1 L vertical pyrolysis reactor, which was a fixed bed design under the determined optimum conditions. The operating conditions were selected at three different temperatures (250, 300 and 350 oC) and two residence times (10 - 30 min). Around 47% mass yield and 60% energy yield of biochar with a calorific value of 23940 kJ/kg were achieved at optimum temperature 300 °C with 30 min residence time. The results showed that reduction of mass and energy yields with increasing the temperature and improvement in heating value and energy density was observed. In addition, the effect of temperature is greater than the residence time. After determining optimum conditions, bio coal was produced in pilot scale torrefaction system. Bio coal properties produced in a pilot system compared with lab scale fixed bed pyrolysis reactor and observed similar properties. In the second part of the thesis, co-gasification of bio coal with lignite in lab scale steam gasification system was investigated. Steam gasification experiments were carried out with lignite, raw- and torrefied biomass, and their blends at different ratios. For comparison, gasification experiments with pyrochar derived from sunflower seed waste at 500 °C were also performed. Notable synergic effect were observed in co-gasification of coal with torrefied biomass at the blending ratio of 1:1. The obtained results showed that in co-gasification of lignite with biomass, the hydrogen yields depend on the volatiles content in biomass/chars, besides their inorganic constituents and hydrogen production significantly increased when co-gasification of bio coal with lignite.
The use of biomass as a renewable fuel has become more interest in the recent years. In order to use biomass economically in large-scale power systems needs to increase its chemical and physical properties. These properties may be improved by torrefaction, which is thermally pre-processing. Torrefaction is an important pretreatment process around 200-350 oC to provide energy enriched solid fuel named as bio coal. In addition to temperature, there are many parameters that affect the torrefaction process. These are residence time and heating rate, as well as raw material particle size and composition. In the first part of this thesis, bio coal was produced from sunflower seed cake in stainless-steel 1 L vertical pyrolysis reactor, which was a fixed bed design under the determined optimum conditions. The operating conditions were selected at three different temperatures (250, 300 and 350 oC) and two residence times (10 - 30 min). Around 47% mass yield and 60% energy yield of biochar with a calorific value of 23940 kJ/kg were achieved at optimum temperature 300 °C with 30 min residence time. The results showed that reduction of mass and energy yields with increasing the temperature and improvement in heating value and energy density was observed. In addition, the effect of temperature is greater than the residence time. After determining optimum conditions, bio coal was produced in pilot scale torrefaction system. Bio coal properties produced in a pilot system compared with lab scale fixed bed pyrolysis reactor and observed similar properties. In the second part of the thesis, co-gasification of bio coal with lignite in lab scale steam gasification system was investigated. Steam gasification experiments were carried out with lignite, raw- and torrefied biomass, and their blends at different ratios. For comparison, gasification experiments with pyrochar derived from sunflower seed waste at 500 °C were also performed. Notable synergic effect were observed in co-gasification of coal with torrefied biomass at the blending ratio of 1:1. The obtained results showed that in co-gasification of lignite with biomass, the hydrogen yields depend on the volatiles content in biomass/chars, besides their inorganic constituents and hydrogen production significantly increased when co-gasification of bio coal with lignite.
Açıklama
Anahtar Kelimeler
Enerji, Energy