Reducing NOx Emissions from Small LPG Furnace by Direct Water Injection
Reduction of thermal NOx emissions from a small scale LPG-fueled cylindrical furnace is attempted in this work by means of direct water spraying into the combustion domain. The water injection is facilitated through four nozzles that inject fine water droplets in the direction of the main gas flow through the furnace. The nozzles are distributed in a cross pattern configuration at the rear side of the furnace. Baseline runs without water spraying have been conducted to establish a basis for comparison and assessment of the runs with water injection. Two approaches of water spraying have been implemented. In the first, water was injected from only two of the four nozzles while the other two were deactivated. In the second approach the same water injection flow rate was adopted but by distributing the water equally to the four nozzles. The emissions results were reported as function of the number of nozzles used. In taking the measurements, two cross sections in the furnace downstream from the fuel and air supply port were considered. In each section, three representative points were selected to sample the measurements of the quantities that are of interest to us in this study. The results show that using the four water injection nozzles at the same time leads to a more pronounced reduction in NOx emissions but at the same time lead to a significant increase in CO emissions. The use of the 2-nozzle configuration is found to be a good compromise for both NOx and CO emissions.