STAC Chlorine0 pages
STAC CL
STAC Chlorine Analyzer
CONTEXT
It is difficult today to measure chlorine whose concentrations
fluctuate from 4 mg/L up to 3 g/L. The problem still becomes
complicated if measurement must be automated. The solutions
which exist to measure chlorine are:
> the colorimetry using reagents and titrimetry. These methods
are not easy to use on line and relate to only the small
concentrations (1.5 mg/L).
> Potential "Redox" measurement. Although usable in process,
the measurement carried out by probe makes dilution impossible
during strong concentration.
SECOMAM offers a powerful and easy to use on line alternative
by direct physical measurement in the UV of the chlorine
concentration from 4 mg/L up to 3 000 mg/L . Much more
SECOMAM Analyzer can simultaneously measure Dissolved
Sulfide (H2S) in 5 - 50 mg/L range.
MEASUREMENT PRINCIPLE
Measurement is based on the acquisition of UV spectrum (204 - 321Nm) of the sample and its
interpretation by a method of calculation called the "Deconvolution". The calculation of "Deconvolution"
is based on two hypotheses:
> the spectrum of the sample is the sum of absorption spectra known as reference spectra;
> the combination of a small number of reference spectra makes it possible to reconstitute the shape of
UV spectrum of an unknown sample.
This small number of spectra of reference is called "Model". After acquisition of the spectrum and its
treatment by the "Deconvolution" method, measurement will give:
- Concentration of the sought parameters,
- Information on the quality of measurement (adequacy between the selected model and the measured
sample)
□1/04/24
Hour
00
10
20
30
1 1 :04
1 :Chl
0.35
0.36
0.36
0.37
ES4
PARA
MEASURED PARAMETER
In this operation, H2S is dissolved at basic Ph, and then converted into Sulfate by Chlorine. The STAC CI is able to trace both Chlorine &
Sulfide.
Chlorine solution spectrum (concentration 1 g/l)
Measured by an STAC CHLORINE analyzer using a flow through cell of 2
mm optical path
Cl2 (free) = Cl2 (aqueous) + HCIO- (Hypochloric ion) + CI" (chloride)
1 11 :• ii r | ■ ■ I ■ r 11_r eel | ||||
: -1 | i y -i : | | ||||
0.300' ■ MW ■ | |||||
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..... | |||||
jjo.so- ■ "' ■. : X , . f i v □.*»■ 1 | |||||
0.350- □.300- ■ | |||||
0.25D- | |||||
0.2K 0.150 0.1OD- ■ | |||||
0.OS0 | |||||
220 M0 MO 2M 300 330 . (---nn i ---ftbs) -1 |
MEASURING RANGE
It is possible to work on three ranges of measurement according to the size of the flow though cell used (2mm, 5mm)
Optical path of flow cell | Chlorine measuring range | Sulfide threshold detection |
2 mm | From 100 to 3000 ppm | 10 ppm |
5 mm | From 40 to 12000 ppm | 4 ppm |
SECOMAM
a xylem brand
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