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BLEACHING AGENTS |
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Chlorine (Cl2) - PVDF and PTFE
can be used up to 200°F and 300°F, respectively,
however The Chlorine Institute, Inc. recommends carbon steel.
Dry Chlorine Service - PVDF and PTFE
can be used up to 200°F and 300°F, respectively,
however The Chlorine Institute, Inc. recommends carbon steel.
Chlorine Water - Liners of PTFE, PVDF
and PP can be used to pipe saturated chlorine water. However, if free
chlorine gas is present, only PVDF and PTFE are usually recommended.
Chlorine Dioxide(ClO2) - Liners
of PVDF and PTFE are appropriate for ClO2. If this line
will also be used for sodium hydroxide, PVDF should not be used.
Sodium Hypochlorite (NaOCl) - NaOCl can be
successfully handled with PTFE, PVDF and PP under normal conditions.
Temperature upsets can cause decomposition to free chlorine gas which
would require PTFE or PVDF. If NaOH is used and the pH could exceed
11, PVDF should not be used.
Bromine (Br2) - A 3% saturated
bromine water solution can be handled with pipe lined with PTFE, PVDF
and PP, while only PTFE and PVDF linings are suitable for liquid
bromine. |
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Commercial bleaching agents are among the most commonly handled
substances in a variety of industries, most notably paper and chemical
pulp, textiles and food. Chlorine, in both gaseous and liquid form,
is perhaps the most important, but chlorine compounds are also widely
used. In some processes, bromine is becoming popular as a substitute
for chlorine.
All of these chemicals and their compounds share, to a certain degree,
two characteristics: they are corrosive and toxic. Under certain
conditions, some are explosive. They are among the most difficult to
handle and work with.
All of the bleaching agents listed exhibit widely varying characteristics,
depending on such things as pressure and temperature, moisture content,
and whether they are in a gaseous or liquid phase. All of these
characteristics are interrelated to some extent. Chlorine, for example,
readily changes state under certain changes in temperature, pressure or
both; many piping materials will handle one form of chlorine but not the
other. The addition of even a few ppm of water to dry chlorine gas
increases its ability to corrode considerably, and thereby eliminates a
number of popular materials from consideration. |
"This page is a machine translation of the source page, which is written in
English. This translation is intended to provide a general idea of the
page's content, and is not guaranteed for accuracy."
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