Control of Volatile Organic Compounds Emissions from Manufacturing

3.1.3.1 Catalytic Incinerator VOC Destruction Efficiency, The
destruction efficiency of catalytic incinerators is a function of many
variables, including type of catalyst, its surface area, volume, and
pore size distribution, gas composition, uniformity of flow through the
catalyst bed, oxygen concentration, and temperature in the unit .26,27
The efficiency of a catalytic incinerator will deteriorate over
time, necessitating periodic repl acement of the catalyst. The repl ace-
ment time varies widely, depending on the service of the unit, from less
than 1 year up to 10 years,12 with an average life between 3 and 5 years,28
A 1980 study by Engelhard Industries for the EPA involved testing
of both pi1 ot and full -scale catalytic incineration systems. The full -scale
unit installed on a formaldehyde plant achieved control efficiencies
ranging from 97.9 to 98.5 percent. These efficiencies represent overall
control levels for carbon monoxide, methanol, dimethyl ether, and formaldehyde.
Measurements indicated the ability of the system to control at this
level consistently over a 1-year period. No trend in the data points
gave indication of a maximum catalyst life.29
3.1.3.2 Applicability of Catalytic Incinerator's. - A catalytic
incinerator is best applied to a continuous stream that is (1) low in
VOlC (higher VOC concentrations lead to higher catalyst temperatures,
which can seriously damage the catalyst activity and possibly create
fire hazards) and (2) free from solid particles and catalyst "poisons."
A catalytic incinerator in many situations may be fitvored over a thermal
-incinerator because it can destroy the VOC at a lower temperature and,
therefore, use less fuel. However, since most of the streams involved
in the polymers and resins industry are high enough in heating value to
sel f-combust without using auxi 1 iary fuel , vi rtual ly no advantage is
achieved by using a catalytic unit and thei r applicabi 1 ity in thi s
industry is very limited.
3.1.4 Industrial Boilers
Fireboxes of boilers and fired heaters can be used, under proper
conditions, to incinerate waste streams that contai n VOC1s. Combusti bl e
contaminants, includi ng smoke, organic vapors, and gases can be converted
essentially to carbon dioxide and water in boiler f'ireboxes. As the
primary purpose of the boiler is to generate steam, a1 1 aspects of
operation must be thoroughly evaluated before this method of air pollution
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