Klaus Hjuler

Wet oxidation of residual product from spray absorption of sulphur dioxide

Abstract The oxidation of calcium sulphite in aqueous slurries of residual product from spray absorption of sulphur dioxide was studied under heterogeneous conditions typical of wet scrubbers. The observed rate of oxidation without additional catalyst was found to be of 0th and 1st order in the sulphite concentration and the partial pressure of oxygen, respectively. With manganeous sulphate added as a catalyst, the order was about 0.5 and 1.0, respectively. Both the residual product and the oxidation product were analysed with respect to composition and characteristics. The oxidation product contained more than 90 wt% gypsum.

Design of a flue gas probe for ammonia measurement

Abstract The emission of nitrogen oxides from combustion can be limited by selective catalytic reduction (SCR) and selective non-catalytic reduction (SNR) by ammonia. In order to control the ammonia slip in these processes it is desirable to measure the ammonia outlet concentration continuously. The problems in doing this are discussed, among which are homogeneous and heterogeneous reactions of ammonia with nitric oxide in the sampling system. The design and test of a diluting flue gas probe is presented, where ammonia is converted to and detected as nitric oxide. The efficiency of various converter designs for the probe was studied in the laboratory.