Numerical research on structure and performance optimization of a pioneering water-cooled fully premixed gas-fired equipment

Abstract

To meet ultra-low emissions, traditional diffused low-nitrogen gas combustion technologies are not effective or extremely laborious in controlling the emissions of NOx. Thus, this study innovatively proposes a water-cooled fully premixed gas combustion technology and explores its impact on pollutant emissions through numerical simulation. The effects of the burner inlet channel’s equivalent diameter (de), the relative positioning of two rows of buried tubes, and the burner type on combustion in the boiler are explored in-depth. As de decreases, a progressive reduction in NOx emissions is observed and an anti-backfiring effect is enhanced. Moreover, using a concave burner and placing buried tubes in the combustion chamber efficiently reduces the combustion temperature and thus NOx emissions. Finally, a ternary phase diagram is constructed to guide structural design optimization and clearly depicts the effect of Airflow channel width (SW), Dimensionless distance between the first row of buried tubes and the burner nozzle (D1), and Dimensionless longitudinal distance of buried tubes (D2) on NOx and CO emissions. Under the optimized structural condition, the water-cooled fully premixed gas combustion reveals great potential to synergistically control NOx emissions to as low as 11 mg/m3 and CO concentration to 10−6 mg/m3. This research provides valuable reference data for theoretical research and equipment design.