Publication: Numerical analysis of hydrodynamics in a pressurized circulating fluidized bed system
Abstract
Küresel enerji talebinin gelecek yıllarda da artacağı ve tüm dünyada güç santrali sayısının artmaya devam edeceği görülmektedir. Buna bağlı olarak fosil yakıtların kullanımı da tüm dünyada artmaktadır. İstatistiklere göre bu talep her yıl bir önceki yıla göre artış göstermektedir. Diğer yandan, küresel ısınma insanlığın günümüzde en önemli sorunlarından birisidir ve küresel ısınmanın en önemli sorumlularından olan fosil yakıtlar, sera gazı salımlarının en önemli kaynağıdır. Enerjiye olan ihtiyaç nedeniyle güç santrallerinin sayısını azaltmak veya üretimini düşürmek mümkün değildir. Ancak bu santrallerin oluşturduğu kirlilik miktarı, verimlerinin arttırılması ile azaltılabilir. Bu alanda son yıllarda birçok araştırma ve çalışmalar yapılmaktadır. Günümüzde bilgisayar teknolojinin ilerlemesi sayesinde hesaplama süresi ve yüksek maliyetinden dolayı araştırılması mümkün olmayan yanma işlemi bugün farklı yönleriyle araştırılabilmektedir. Sayısal modelleme çalışmaları ve analizler, araştırmacılara karmaşık işlemler üzerinde çalışmalarına olanak sağlamaktadır. Böylece, sayısal modelleme yöntemi ile deneysel yöntemlerle zor ve pahalı olan ölçümler yapılabilmekte ve sistemler tasarlanamaktadır. Diğer yandan, simülasyonlarla elde edilmiş sonuçların laboratuvar verileri ile doğrulanması, yanma işlemlerinin geliştirilmesi ve araştırılmasında önemlidir. Bu tez çalışmasında, laboratuvar verisinin ve yanma teorilerinin incelenmesiyle basınçlı bir Dolaşımlı Akışkan Yatak Sistemi sayısal olarak incelenecektir. Bu analizler sonucunda, akışkan yatak reaktöründe yanma verimini arttırmak ve çalışma parametrelerinin etkileri detaylı olarak incelenecektir. Geliştirilecek sayısal model ileride yapılacak boyut yükseltme çalışmalarında da kullanılabilir.
The global energy demand is predicted to increase in the coming decades. And every year the number of power plants around the world is increasing. Besides, the use of fossil fuels in the world is increasing, and the statistics show that this demand has increased every year compared to last year. On the other hand, environmental pollution is one of the main concerns of humans, and fossil fuels are one of the main sources of greenhouse gas emissions. It is not possible to reduce the number of power plants or reduce their production at the moment. However, the amount of pollution they produce can be decreased by increasing their efficiency, which requires a more detailed analysis of the processes taking place inside these power plants. Although studies and researches have been done in this field in the past years, today, thanks to the advancement of technology, the combustion process can be studied from other aspects, which were not possible before due to computational time and high cost. Numerical studies and analysis can greatly help researchers to study the complex processes so that they can not only use it to better understand the process, but also explore aspects of process behavior that may not have been possible before in experimental models. On the other hand, what is important is to ensure that the simulated model is well developed to represent the real laboratory model. Therefore, it can be said that verifying laboratory data with corresponding simulation models plays an important role in improving and investigating the combustion process. In this study, we will try to obtain the closest simulation model by examining laboratory data and combustion theories so that we can rely on the results to evaluate the effective parameters to increase the output efficiency of the fluidized bed-chamber. The developed model can be also used for further scale-up studies.
The global energy demand is predicted to increase in the coming decades. And every year the number of power plants around the world is increasing. Besides, the use of fossil fuels in the world is increasing, and the statistics show that this demand has increased every year compared to last year. On the other hand, environmental pollution is one of the main concerns of humans, and fossil fuels are one of the main sources of greenhouse gas emissions. It is not possible to reduce the number of power plants or reduce their production at the moment. However, the amount of pollution they produce can be decreased by increasing their efficiency, which requires a more detailed analysis of the processes taking place inside these power plants. Although studies and researches have been done in this field in the past years, today, thanks to the advancement of technology, the combustion process can be studied from other aspects, which were not possible before due to computational time and high cost. Numerical studies and analysis can greatly help researchers to study the complex processes so that they can not only use it to better understand the process, but also explore aspects of process behavior that may not have been possible before in experimental models. On the other hand, what is important is to ensure that the simulated model is well developed to represent the real laboratory model. Therefore, it can be said that verifying laboratory data with corresponding simulation models plays an important role in improving and investigating the combustion process. In this study, we will try to obtain the closest simulation model by examining laboratory data and combustion theories so that we can rely on the results to evaluate the effective parameters to increase the output efficiency of the fluidized bed-chamber. The developed model can be also used for further scale-up studies.