CH4-CO2 Fuel Mixture Combustion and Emission Characteristics in a Combi Boiler Combustor

Year 2024, EARLY VIEW, 1 - 1

Ahmet Haşim Toslak , Halil İbrahim Variyenli , Serhat Karyeyen

https://doi.org/10.2339/politeknik.1509907

Abstract

Biogas can be obtained from agricultural, animal, and waste, replacing natural gas in heating systems. Because of that, studying its combustion characteristics will be valuable. This study investigates biogas combustion characteristics in a natural gas-powered heating system. Various CH4-CO2 biogas fuel mixtures were analyzed experimentally and numerically for a thermal power of 13 and 31 kW. In the experimental part of the study, the fuel mixtures were burned, and the temperature and the NOX were measured. The standard k-ε turbulence model and Eddy Dissipation Concept were used in the present study's numerical part. The model was validated with the measured data. The modeling results are in agreement with the measurements. Various fuel mixtures were then modeled to seek varying inlet temperature and O2 concentration effects on the combustion characteristics of the biogas fuel mixtures studied. It was concluded that as the amount of CO2 in the fuel mixture was increased the flame temperature decreased linearly from about 1900 K to 1775 K. NOx concentrations in the combustion product decreased from about 10 ppm to below 2 ppm. It was also concluded that air preheating and change in O2 concentration in the oxidizer affected the flame temperatures and NOx considerably.

Keywords

Biogas, Combustion, Domestic Boiler, CFD, Emission

CH4-CO2 Yakıt Karışımının Kombi Yanma Odasında Yanma ve Emisyon Karakteristikleri

Abstract

Tarımsal, hayvansal ve atıklardan elde edilebilen biyogaz, ısıtma sistemlerinde doğal gazın yerini alabilir. Bu nedenle yanma özelliklerini incelemek değerli olacaktır. Bu çalışmada doğal gazla çalışan bir ısıtma sisteminde biyogazın yanma özellikleri araştırılmaktadır. Çeşitli CH4- CO2 biyogaz yakıt karışımları 13 ve 31 kW ısıl güç için deneysel ve sayısal olarak analiz edilmiştir. Çalışmanın deneysel kısmında yakıt karışımları kombide yakılarak sıcaklık ve NOX değerleri ölçülmüştür. Çalışmanın sayısal kısmında standart k-ε türbülans modeli ve Eddy Dissipation Concept kullanılmıştır. Sayısal model deneysel verilerle doğrulandı. Sayısal model ile farklı yakıt karışımları için farklı giriş hava sıcaklıklarının ve O2 konsantrasyonunun etkisi de incelenmiştir. Yakıt karışımındaki CO2 miktarı arttıkça alev sıcaklığının doğrusal olarak yaklaşık 1900 K'den 1775 K'ye düştüğü görülmüştür. Yanma ürünündeki NOx konsantrasyonunun yaklaşık 10 ppm'den 2 ppm'nin altına düştüğü görülmüştür. Ayrıca hava ön ısıtmanın ve oksitleyicideki O2 konsantrasyonu değişiminin alev sıcaklıklarını ve NOx değerini önemli ölçüde etkilediği sonucuna varılmıştır.

Keywords

Biyogaz, Yanma, Kombi, HAD, Emisyon

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