NUMERICAL INVESTIGATION OF THE POTENTIAL OF USING HYDROGEN AS AN ALTERNATIVE FUEL FOR AN INDUSTRIAL BURNER

Abstract

The impact of emissions resulting from burning many types of fuels is one of the biggest problems that affect the environment. Attention has recently been drawn to using some gases and mixing them with specific types of pure fuels to obtain fuel mixtures that have suitable combustion characteristics and have lower emissions than those resulting from burning pure fuels. The literature review of the research focused on clarifying the impact of enhancing hydrogen, oxygen, and carbon dioxide to fuel mixtures in terms of variation in the ignition, flame stability, and combustion characteristics. The literature review shows that adding hydrogen to CH-CO2 mixtures improves the flame stability significantly in contrast to carbon dioxide added to oxy-methane. The highest flame stability is recorded at 24% oxygen, but the flame stability decreases when the oxygen rate increases to 28%. Also, combustion stability improves when hydrogen is added to fuel mixtures and improves when oxygen enrichment is 24% in contrast to oxygen enrichment of 26% as well as adding carbon dioxide which causes a reduction in combustion stability. Moreover, adding hydrogen to methane significantly reduces the ignition delay time. The focus in the research is about how enhancing hydrogen to hydrogen-methane mixture affects the temperature profile, carbon dioxide emission, and NOx emission. The work has been divided into two main studies, which are: studying the impact of adding hydrogen at different percentages to hydrogen-methane mixture and studying the impact of varying the total MFR of fuel of pure hydrogen on the temperature profile. ANSYS FLUENT software has been used to perform all the studies. according to the result of the first study, the composition of 75% hydrogen and 25% methane has the closest temperature profile to pure methane and has the lowest NOx and CO2 emissions compared to the other hydrogen-methane mixture. The second study shows that reducing the total MFR of the fuel by 20% has the closest temperature profile to that of pure methane. In addition, NOx emission levels rise as the total fuel MFR decreases, but it starts to reduce as the total fuel MFR increases. An additional study was computed which is about varying the total MFR of air in a pure hydrogen study, and best case achieved that would improve the temperature profile is enhancing the MFR of excess air by 10%. Further studies such as studying the impact of enhancing oxygen and carbon dioxide to the hydrogen-methane mixture can be done, as well as studying the effect of staged fuel angle and burner geometry.