The Effect of Nitrogen on Flame Characteristics in Biogas External Premixed Combustion

Abstract

Biogas contains more than 50% methane (CH4), is a renewable and eco-friendly fuel produced by bacterial action. Not only is biogas flammable but it also contains inhibitors like carbon dioxide and nitrogen, as well as small amounts of H2, O2, H2S and others. Several associated studies have been conducted in order to examine biogas combustion characteristics in external combustion and flame angle, flame height and dimensionless flame height are the important characteristics in external premixed combustion. This research’s aims were to discover the influences of N2 as it is the second most prevalent inhibitor in biogas by burning stoichiometric fuel mixtures (CH4 and N2 (0%-50% of fuel)) and oxygen in an experimental external premixed combustion burner whose nozzle tip diameter was 5 mm. The burner was connected to a hose from the oxygen tank and another hose from the fuel tank. Two regulators and flowmeters were placed on each tank to monitor the flow supplied to the mixer and burner. The valves were used to stop or open the fluid supply. The outcome flame propagation is then recorded by a high speed camera and then processed through a computer system. The results indicate that N2 influenced the flame angle, flame height and dimensionless flame height. The higher the N2 content inside the fuel, the shorter the flame height and the lower the dimensionless flame height. Moreover, increasing the N2 content created larger the flame angle.

The Explosion Severity of Biogas(CH₄-CO₂)/Air Mixtures in a Closed Vessel

“…Therefore, the presence of 45% vol/vol CO2 in biogas has a greater ability to absorb the heat combustion. This phenomenon may change the flame stability [6,18] and hence reduce the flame temperature that can lower the overall mass burning rate which reflects Pmax and (dP/dt)max. Hence, biogas containing 55% vol/vol CH4 and 45% vol/vol CO2 leads to the least effect on the explosion severity.…”

“…Although biogas also contains traces of hydrogen sulfide (H2S) and other compounds, the explosivity characteristic of biogas is not affected due to its small concentrations [2][3][4][5]. CO2 is a substance which has difficulty to react [6]. In general, the presence of CO2 in biogas has a negative impact on the normal burning velocity and maximum rate of pressure rise due to its extraordinary inerting potential [7].…”

Effect of Various Supercharger Boost Pressure to in-Cylinder Pressure and Heat Release Rate Characteristics of Direct Injection Diesel Engine at Various Engine Rotation

“…In order to prevent energy crisis to eventuate, many methods have been devised. Most known method is the use of renewable fuel like biogas, biodiesel from edible and non-edible source, and briquette which are cheaper and beneficial in economy aspect [2][3][4][5][6]. Another method is to raise the efficiency of instrument used to produce energy.…”