OCR Text |
Show 4) Results of NOx control operation (1) NOx concentration The results obtained from the NOx control operation at each Wasteto- Energy Plant are shown be low: Spec. Figure Number Plant A 300ton/24h x 3 furnaces Fig . 1-7 - 1-9 Brick type Plant B 300ton/24h x 2 furnaces Fig. 1-10 Water wa II type Plant C 200ton/24h x 3 furnaces Fig. 1-11 - 1-13 Brick type Plant 0 100ton/24h x 2 furnaces Fig. 1-14 - 1-15 Brick type (2) Relationship between NOx and 02 Fig. 1-16 shows the relationship between tWx and O2 of the combustion chamber. The tendency is the lower the 02. the lower the NOx. (3) Relationship between transition of reduct ion g~s in the furna ce and NOx The concentration of reduction gases Oh . CO. C11 4 • Nih . lieN) in the drying zone. bypass-flue and after burning chamber is shown in Fig. 1-17 - 1-19 with NOx as a parameter. From the results the following tendency may be pointed out: 1 ) The higher the concentration of reduction gas in the drying zone above the drying grate, the lower the NOx. Ii) As the re-combustion of the reduction gas takes place effectively in the after burning chamber that is designed so as to carry out mixing of flue gas thoroughly, problems, such as adverse effects on equipment in the down stream of boiler, unburnt gas discharge, etc. can be avoided. 5 |