Applications of optical measurement technology in pollution gas monitoring at thermal power plants
2011
This paper presents the work of using advanced optical measurement techniques to implement stack gas emission
monitoring and process control. A system is designed to conduct online measurement of SO 2 /NO X and mercury emission
from stacks and slipping NH 3 of de-nitrification process. The system is consisted of SO 2 /NOX monitoring subsystem,
mercury monitoring subsystem, and NH 3 monitoring subsystem. The SO 2 /NO X monitoring subsystem is developed based
on the ultraviolet differential optical absorption spectroscopy (UV-DOAS) technique. By using this technique, a linearity
error less than ±1% F.S. is achieved, and the measurement errors resulting from optical path contamination and light
fluctuation are removed. Moreover, this subsystem employs in situ extraction and hot-wet line sampling technique to
significantly reduce SO 2 loss due to condensation and protect gas pipeline from corrosion. The mercury monitoring
subsystem is used to measure the concentration of element mercury (Hg 0 ), oxidized mercury (Hg 2+ ), and total gaseous
mercury (Hg T ) in the flue gas exhaust. The measurement of Hg with a low detection limit (0.1μg/m 3 ) and a high
sensitivity is realized by using cold vapor atom fluorescence spectroscopy (CVAFS) technique. This subsystem is also
equipped with an inertial separation type sampling technique to prevent gas pipeline from being clogged and to reduce
speciation mercury measurement error. The NH 3 monitoring subsystem is developed to measure the concentration of
slipping NH 3 and then to help improving the efficiency of de-nitrification. The NH 3 concentration as low as 0.1ppm is
able to be measured by using the off-axis integrated cavity output spectroscopy (ICOS) and the tunable diode laser
absorption spectroscopy (TDLAS) techniques. The problem of trace NH 3 sampling loss is solved by applying heating the
gas pipelines when the measurement is running.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
1
Citations
NaN
KQI