Classification of Technology:
Air Pollution Control Type of Industry:
Petroleum Refining Subject:
Reduction of NOx Discharged from Catalyst Regenerator
1. Purpose
To reduce nitrogen oxides ( NOx ) in the exhaust gas discharged from a catalyst regenerator of a fluidized catalytic cracker from 500ppm to 250ppm in order to observe the regulation of the Air Pollution Control Law.
2. Details and the Time of Introduction
The concentration of NOx and dust is high in the exhaust gas from the catalyst regenerator and the amount of exhaust gas itself is also big. The dry type flue gas denigration equipment was therefore introduced suitable for the exhaust gas. ( June, 1988 )
3. Principle
The dry type flue gas denitration equipment injects NH3 in the exhaust gas and breaks down NOx in the exhaust gas with the action of the catalyst into N2 and H2O .
Since NOx is broken down into harmless N2 and H2O, post-treating process such as treating of drain is not necessary.
A general outline of process flow is shown on the next page.
5. Future Subject
In flue gas denigration using ammonia, the denitration performance gradually drops because of the acidic ammonium sulfate formed by SO3 and NH3 contained in the exhaust gas, and both the downstream corrosion and the blocking problem become important.
When using continuously for extended period, it will be necessary to obtain the optimum processing temperature based on these reaction characteristics.
