STAC CL0 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

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1 1 :04

1 :Chl

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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)

MEASURING RANGE

It is possible to work on three ranges of measurement according to the size of the flow though cell used (2mm, 5mm)

SECOMAM

a xylem brand