USE OF HYDROGEN AS A NONCONVENTIONAL ALTERNATIVE FUEL IN COMBUSTION PROCESSES WITH LOW NOX EMISSIONS

Abstract

The paper presents an experimental oxyhydrogen burner with a thermal power of 31.5 kW (9 m³N hydrogen/h) designed for industrial use at high temperature with NO_x emissions at a relatively low level. The method adopted for the design consisted in mixing hydrogen with oxygen in two successive stages, the concentration of oxygen in the last stage being reduced below 20%. By this method, the flame temperature was reduced to around 1800 ºC allowing the decrease of NO_x (measured as NO₂) emissions below 240 mg/m³N, i.e. below the maximum allowed limit (300 mg/m³N) in the case of natural gas combustion with air. The advantage of using this "clean" alternative fuel under the conditions of operation only with oxygen is removing the possibility of polluting the atmosphere with greenhouse gases (CO₂), the waste gases released being only water vapor.