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Catalytic
combustion for waste gases from PET production
The production of PET (bis-2-hydroxyethyl terephthalate)
also produces waste gases such as aldehyde,
2-methyl-1,3-dioxolane, glycol and etc which if directly
vented, will exceed the limit stipulated by GB16297－1996
and severely endanger the health of the people working
around.
At present, PET
plants generally use burning and water absorption to treat
PET waste gases, which, however, is not satisfactory due
to considerations such as system pressure balance, safety,
lower pollutants removal, secondary pollution, and
etc.
FRIPP, JICA and
a domestic refinery have developed the water
absorption-catalytic combustion process and carried out
the pilot test.
With water
absorption, glycol can be effectively removed and the
total hydrocarbon concentration in waste gas is uniform so
that the temperature of reactor outlet is stable. In
catalytic combustion process, the catalyst operated for 95
accumulative days without showing activity loss under LHSV
,40000h－1
; reactor inlet temperature 250℃.
The pressure drop along catalyst bed is 30～38Pa/cm
bed height.
The pilot test of the combined process showed that,
treating PET waste gas with water absorption—catalytic
combustion combined process under proper conditions, the
total hydrocarbon concentration and aldehyde concentration
are both within the limit of the national standard. The
purified gas has no unpleasant odor.
This process is now under commercial test.
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