Control of Volatile Organic Compounds Emissions from Manufacturing

elow the 0.12 kg VOC/1000 kg of product level (through the use of
vacuum pumps) because of economic incentives. The 0.20 kg VOC/1000 kg
of product VOC level is based on the plant that currently has the
greatest known emissions. Both emi ssion levels were costed for styrene-
in-steam emissions as we1 1 as for styrene-i n-ai r emi ssi ons.
Both of the units examined for recovery of styrene in steam require
only a minimum commercially available size condenser unit with 20 ft2
heat transfer area. Therefore, as shown in Table 5-1.2, the only difference
in the costs of the two units is the amount of the recovery credit.
The total installed capital cost and annualized cost of both units are
$28,000 and $8,300 per year, respectively. The net annualized costs
considering recovery credit are $-147,000 per year for a reduction from
3.09 kg/1000 kg and $4,130 per year for a reduction from 0.20 kg/1000 kg.
For the recovery of styrene in air, a minimum commercially available
size condenser unit with 20 ft2 heat transfer area is requi red when the
uncontrolled emission rate is 0.2 kg VOC/Mg of product. If the
uncontrolled emission rate is 3.09 kg VOC/Mg of product, then a condenser
with 185 ft2heat transfer area is required to remove the styrene from
the styrene-i n-ai r emi ssions.
Only one additional cost analysis was undertaken for the polystyrene
plant because the model plant consists of only two process lines and only
one process section for which RACT is being recommended. The additional
cost analysis looks at controlling emissions from a single process
lfne. The results of this cost analysis are summarized in Table 5-13.
5.3 COST EFFECTIVENESS OF RACT
The annualized cost effectiveness values (net annualized cost per
megagram of VOC emission reduction) are given in Tables 5-14, 5-15, and 1
5-16 for the various control techniques and model plant combinations.
The estimated costs of emission reduction (using the lowest cost combustion
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control option of flares for PP and HDPE) are only $13 and $17 per
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megagram of VOC reduced from uncontrolled levels, for polypropylene and
high-density polyethylene, respectively. Even for a reduction from the
assumed upper level of existing control for which acldi tional or replacement
control might be required, the cost of the same control techniques
would be about $88 and $160, per megagram. For the polystyrene model
plant, the condenser analysis results in a range in the potential cost
5-28
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