Functional Sequence - GRUNDFOS ALLDOS Oxiperm C 164 Series Operation And Service Manual

4.2 Functional Sequence

14
According to the Oxiperm
hydrochloric acid is used for the following reasons:
❏ A non-critical chlorine dioxide concentration of 20 g ClO
the reactor of the Oxiperm
WARNING
!
❏ A good yield of chlorine dioxide is achieved with excess acid of 250 -
300%. A further increase in the excess acid only results in a small
improvement in the efficiency.
❏ Excess acid shifts the equilibrium of the disproportionation reaction
between hydrochloric acid and sodium chlorite to the right, resulting in an
optimum yield.
❏ Three components are required to generate a chlorine dioxide solution:
- Hydrochloric acid (HCl)
- Dilution water (H 2 O) for HCl
- Sodium chlorite (NaClO 2 )
- Dilution water (bypass )
The added quantities of these components are defined by the process, and
must not be changed. The flows of the individual components are therefore
monitored by flowmeters and flow controllers.
❏ Hydrochloric acid (33% solution) and sodium chlorite (24.5% solution) are
dosed into the reactor with a volume ratio 1:1 together with the dilution
water for HCl.
❏ Hydrochloric acid and sodium chlorite react together in the reactor and
generate a concentration of approx. 20 g/l
❏ Following the reactor, the chlorine dioxide solution is diluted by the bypass
water into a solution ready for use.
Bypass wa t er
®
C 164 application, a multiple stoichiometric excess of
® C 164.
A chlorine dioxide solution with a concentration of
30 g / l may explode if a gas area is present above the
solution.
Gaseous chlorine dioxide is explosive above a
concentration of 300 g / m
Reactor
HCl
NaClO 2
Oxiperm 164 150-2500 g en
/ l is generated in
2
3 .
ClO2 solution
H 2 O
15.710010-V5.0