Stability of Partially Premixed Ammonia/Methane Flames in a Concentric Flow Conical Nozzle Burner

Ammonia, as a carbon-free fuel, holds promise as a potential alternative to fossil fuels. However, its practical implementation requires a comprehensive understanding of its combustion properties, particularly concerning flame stability. This study investigates the stability and flame appearance of partially premixed ammonia-methane flames in a concentric flow conical nozzle burner. The research explores the effects of varying the ammonia fraction in the inner stream, the outer stream velocity, and the degree of partial premixing (expressed as L/D). The findings indicate that flame stability is enhanced by increasing the outer stream equivalence ratio, while it is reduced by increasing the degree of premixing via higher L/D values. Notably, the case of L/D = 0 demonstrates a virtual improvement in flame stability, attributed to the absence of reaction between the inner mixture and the stable outer methane flame. This study provides valuable insights into the combustion characteristics of ammonia-methane blends under partially premixed conditions

Cofiring of Oil and Gaseous Fuels Through an Innovative Coaxial, Double Swirl Burner

This paper presents a newly designed coaxial burner capable of simultaneous combustion of oil and gas fuels. The burner addresses the need for renewable energy production from syngas and biofuels derived from solid waste. The focus is on evaluating the burner's effectiveness in co-firing light diesel fuel and LPG, including flame appearance and exhaust emissions. The study establishes a reference for future comparisons when burning syngas and blended biofuels. The burner configuration allows for various influential variables, such as oil/gas ratio, and inner/outer air ratio. The evaluation concentrates on visible flame appearance, exhaust emissions, and heat transfer to the cooling water jacket. The experiments are conducted at a fixed 55 kW input load. Results indicate that different inner/outer air ratios have minimal impact on CO_2 and O_2 levels but affect CO and NOX levels, both in single fuel burning and co-firing scenarios. Increasing inner air reduces CO levels, particularly in oil fuel burning, while decreasing inner air reduces CO levels in co-firing

Effect of Inner Swirl Angle on Flame Stability of a Double-Swirl Burner with Biogas-Methane Co-Firing

This paper studies how the inner swirl angle affects the flame stability of a double-swirl burner with biogas-methane co-firing. Biogas is a renewable fuel that is produced from organic waste by anaerobic digestion, it can be mixed with methane as an act to save methane fuel as well reduce CO_2 emissions. However, biogas has combustion challenges due to its high CO_2 content. The double-swirl burner is a technology that can improve combustion performance and reduce nitrogen oxide emissions. This study investigates different inner swirl angles with various CO_2 fractions in biogas and assesses their effects on flame stability and flame appearance. The paper finds that a higher CO_2 fraction and inner swirl angle make the flame less stable and requires more fuel, and also changes the flame shape. The paper gives insights into improving the double-swirl burner for biogas-methane co-firing