OCR Text |
Show Therefore. it is necessary to hold the Hlb/HOx ratio below 1.2 to 1.5 leve 1. The relationship between the temperature of a reaction zone and denitrification raLio becomes as shown in Fig. 1-25. showing the maximum value in the neighborhood of ~o F (~t;). I, "00 870 4) Know-how acquired from existing plants The know-how acquired through experiments and operation data and operation experience of existing plants can be summarized as follows: i ) There should be no flames at the position of atomizing the reducing agent. Ii) The mixing of the reducing agent and NOx should be thorough. iii) The reaction zone can be maintained at an adequate temperature. Iv) A sufficient gas residence time (longpr than 0.4 seconds and preferably longer than one second) can be kept in the reaction space. 5) Advantages of systems i ) Simple system and maintenance free This system requires only an ammonia water tRnk (rylinder or ammonia storage tank in the case of ammonia gas). flowmeter . piping, nozz le. etc. and is extremely simple. Therefore there will be no trouble. high reliability and almost maintenance free. ii) Stable denitrification efficiency The automatic non-catalytic denitrification control system calculates an adequate addition of the reducing agent from the process data, such as exhaust gas volume, HOx concentration. 02 concentration temperature in the after burning chamber. etc. and the reducing agent is atomized. 9 |