Document Details
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Document Type |
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Thesis |
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Document Title |
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COMBUSTION STABILITY AND EMISSION OF A PREMIXED METHANE/AIR FLAME WITH HYDROGEN AND HYDROGEN-AMMONIA BLENDS ADDITION استقرار الاحتراق وانبعاثات لهب غاز الميثان والهواء المخلوط مسبقاً مع إضافة مزيج الهيدروجين والأمونيا |
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Subject |
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Faculty of Engineering |
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Document Language |
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Arabic |
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Abstract |
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The demand on energy coming from petroleum is continuously increasing because of the rapid growth in the population of the entire world, as well as the significant energy density found in this energy carrier. Besides the substantial amount of energy associated with fossil fuels, they are responsible for significant amount of pollution, including greenhouse gas emissions, e.g., carbon dioxide (CO2) and nitrous oxide (NOx). In this regard, lean premixed combustion mode has become attractive for utilization in industrial gas turbines due to its ability to meet strict emissions regulations without compromising engine efficiency. However, the burner with this type of combustion mode can suffer from thermoacoustic instabilities, which can lead to flame quenching and/or damaged equipment. In such a combustion mode, the mixing process and the fuel type are the key players that affect the flame structure, stability, and generated emissions. Many studies have investigated the aspects that influence premixed flames, including the effects of turbulence, combustor geometry, and level of partial premixing, while mostly using conventional natural gas fuel represented by methane. Recently, hydrogen and ammonia, sustainable energy sources, have been considered in gas turbines as they are carbon-free fuels producing no CO2. Utilizing 100% ammonia/hydrogen or a blend of methane and ammonia/hydrogen will alter the combustion performance of a premixed flame due to the variation associated with the physical and chemical properties of ammonia/hydrogen. Thus, investigating the coupling between blend ratios and mixing length of methane-ammonia\hydrogen on flame stability and emissions is an essential step toward implementing ammonia/hydrogen in industrial gas turbines. In this thesis, the influence of various methane-ammonia/hydrogen blends and mixing lengths on the flame performance and emissions are studied. The mixing length is altered by using three fuel ports located at three different heights upstream of the combustion chamber. The combustion stability is quantified by measuring flame lean blow-off utilizing a laboratory swirl burner, while the emission gases at the chamber outlet are measured using a commercial gas analyzer. Moreover, to understand the obtained results, a micro spectrometer was utilized to capture the critical chemiluminescence of the flame, e.g., NO*, OH*, CN* NH*, CH* and CO2*. For methane-ammonia blends, the results showed that the flame stability is negatively influenced by increasing (decreasing) ammonia fraction (mixing length ratio) and is more sensitive to the ammonia fraction than to the mixing length. When a small amount of hydrogen (15% volume fraction) was introduced with ammonia (75% volume fraction) and 10% methane, the equivalence ratio at lean blowoff limit reduced to 0.32, with significant flame stability enhancement, compared to 0.53 for mixture compositions of XNH3 = 75% and XCH4 = 25%. For methane-ammonia blends, at a constant equivalence ratio, the CO and NOx performances improved positively by increasing the ammonia volume fractions (especially at XNH3 = 75% compared to XNH3 = 25% and 50%) and the mixing length. |
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Supervisor |
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Dr. Radhi Al-Salami |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Added Date |
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Tuesday, November 28, 2023 |
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Researchers
| مروان حسن العبد الله | Al-Abdullah, Marwan Hassan | Researcher | Master | |
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