Control of Volatile Organic Compounds Emissions from Manufacturing

A condenser is expected to be the major control device used as RACT
for polystyrene continuous processes. There should be no generation of
secondary ai r pollutants by condensation.
4.3 WATER POLLUTION
Combustion systems do not generate an effluent water stream.
(Boi lers do generate an. effluent water stream duri ng bl owdown, but
cornbustion of VOC generates neither additional effluent nor changes in
effluent characteri sti cs.) The condensers for each polystyrene* model
plant could require as much as 38,000 gallons of make-up water (at a
cost of about $12 per year). Most of the condenser water losses, however,
would be expected to be by evaporation rather than by discharge.
4.4 SOLID WASTE DISPOSAL
Generation of solid wastes is not an expected result of control by
RACT in any model plant under consideration. Relatively small amounts
of used catalyst would be generated if a catalytic incinerator were used
to separately control some of.the low VOC streams.
4.5 ENERGY
Tables 4-5, 4-6, and 4-7 present the additional amount and type of
energy required after control within each model plant by RACT. The contro
techniques analyzed for RACT are flares, thermal incinerators, and
catalytic incinerators for polypropylene and hi gh-densi ty pol yet hylene I
and condensers for polystyrene. These control techniques requi re
steam, natural gas, and electricity. Total estimated energy consumption
is presented for each application in equivalent barrels of distil late
oil and total cost.
For a flare, steam is generally used to ensure smokeless combustion.
Natural gas is used for pilot flames to assure ignition and subsequent
combustion of the waste gas. The combined streams from the liquid-phase
processes of both polypropylene and high-density polyethylene production
have high enough heat contents that no supplemental fuel is required.
In addition, for this same reason, no supplemental fuel is required for
the control of emissions from individual process s&tions for those
process sections controlled by a flare. As the flow rate of the flares
I