Multipurpose gas purification process for the reduction of nitrogen oxides

摘要

The invention serves for purifying industrial exhaust gases. The gaseous, liquid and solid pollutants are eliminated or greatly reduced by means of a 10 stage scrubbing at temperatures of 40 to 110 DEG C and slight vacuum of approximately 100 mm water column. The multipurpose gas purification process is particularly suitable for the purification of nitrogen oxide-containing exhaust gases. The NOx transformation proceeds through the following process steps: transformation of the nitrogen oxides NO and NO2 in a dry activated coke bed into nitrogen; additional adsorption of inorganic and organic pollutants (e.g. SO2, HCl, HF, dioxins, furans, etc.) and retention of dusts, heating to 110 DEG C by injection of saturated steam, spray absorption with NH3-water or urea solutions, catalytic reaction of NOx with NH3 or urea solutions to form nitrogen and water in the activated coke bed, water-spray scrubbing, repeated liquid-phase separation and discharge during the purification process, adding fresh air as required. All purification steps and process sequences are arranged in a simple horizontal or vertical, easily handled metal or plastic combination scrubber.