Fundamental Study on Ammonia Low-NOx Combustion Using Two-Stage Combustion by Parallel Air Jets

Ammonia, which has advantages over hydrogen in terms of storage and transportation, is increasingly expected to become a carbon-free fuel. However, the reduction of fuel NOx emitted from ammonia combustion is an unavoidable challenge. There is the report that two-stage combustion with parallel independent jets could achieve Low-NOx combustion under ammonia/methane co-firing conditions. In order to further improve NOx reduction, we experimentally evaluated the effects of secondary air nozzle parameters, such as nozzle diameter and nozzle locations, on combustion characteristics in two-stage combustion of ammonia/natural gas co-firing using parallel independent jets. As a result of the experiments under various secondary air nozzle conditions, it was found that under the conditions where NOx was significantly reduced, the peak temperature in the furnace was observed at 300–500 mm in the axial direction from the burner, and then the temperature decreased toward the downstream of the furnace. We assumed that this temperature distribution reflected the mixing conditions of the fuel and secondary air and estimated the combustion conditions in the furnace. It was confirmed that the two-stage combustion was effective in reducing NOx by forming a fuel rich region near the downstream of the burner, and the lean combustion of the unburned portion of the first stage combustion with secondary air. We confirmed that the low NOx effects could be achieved by two-stage combustion using independent jets from the same wall under appropriate combustion and air nozzle conditions.

Improving of ventilation efficiency at air distribution by the swirled air jets

The article is devoted to decision of actual task of air distribution efficiency increase due to swirled air jets application. The aim of the paper is investigation of swirled air jets, analytical dependencies obtaining for determination of the air velocity attenuation coefficient, aerodynamic local resistance coefficient and noise level from the twisting plates inclination angle; optimization of the twisting plates inclination angle of the air distributor. It has been established that increase of the angle results in the air velocity attenuation coefficient increase and results in decrease of the noise level and resistance coefficient of air distributor. The optimum angle of the plates is determined considering aerodynamic, noise and energy aspects and equals 36°.

Reduction of soot carbon in the exhaust gases of a tractor gas-diesel engine

The rate of oxidation of carbon (including its dispersed forms) has a value much higher than the rate of gasification. Therefore, in the initial part of the flame, when oxygen is still contained in the gas phase, the oxidation of soot will be the process on which the change in the size and concentration of dispersed carbon particles mainly depends. The intensity of oxidation and gasification of dispersed carbon in the flame largely depends on the development of the mixing process, determined by the aerodynamics of the fuel and air jets. The paper presents an analysis of the influence of mixing processes on the oxidation and gasification of dispersed carbon in a natural gas flame in the study of homogeneous flames and mixing of turbulent jets. The results of industrial studies of the mixing of fuel and air in a diffusion torch are taken into account. The results allow us to evaluate the influence of various aerodynamic factors on the processes occurring in the glowing flame of natural gas in the combustion chamber of gas diesel.