Chemistry Reference
In-Depth Information
0.960
0.955
0.950
0.945
0.940
0.935
0.930
118
700
118
750
118
800
118
850
118
900
118
950
119
000
Time (min)
5.14
Test 5 after 82 days. Calibration point is first point of test 1,
hydrogen peroxide concentration is measured and controlled.
Concentration obtained through the sensor system (—) and
through titration (
¥
).
influence on the quality of the bleached product. Already, at this stage of
the development, it became clear that a sensor system monitoring the
hydrogen peroxide concentration continuously offers significant improve-
ments to the process.
In the fifth and final test, of which the results are shown in Fig. 5.13, the
metering pumps (until then manually operated) are coupled to the regu-
lating unit of the sensor system. It can be observed that the hydrogen per-
oxide concentration during the measuring period of 5 h is maintained
between 0.940 and 0.955 mol l
-1
with error margins between sensor output
and titration of less than 2%, which demonstrates the advantages and the
possible applications of the sensor.
Similar tests were performed at a second German company. These tests
led to analogous conclusions, namely that the sensor system is capable not
only of measuring hydrogen peroxide concentrations with sufficient accu-
racy, but also that the process can be directed to an optimal hydrogen per-
oxide concentration which is set in advance. Finally, the sensor was tested
in a third company, also located in Germany. An additional asset of this 50-
day test is that it can be performed mainly by employees at the company.
