Page 72 - Air Pollution Control Engineering

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52 Lawrence K. Wang et al.

presented the calculation procedures for estimating the effects of these changes.
Quantitative gas stream calculations were presented in Section 7.

11. CONCLUSIONS
The US President’s Council on Environmental Quality (CEQ) annual reports since 1973
have shown a positive investment return on control equipment. These reports show that an
investment return of nearly 15% from the purchase and installation of control equipment
can be obtained in the United States. Even though there are numerous ways that data can
be interpreted to estimate investment return, these annual reports provide positive
reinforcement for providing control equipment. We are moving in the right direction.
In order to make sound decisions on the selection of air pollution control equipment,
it is necessary to have solid data on air pollutants. Such data can be obtained by dili-
gent, careful work, knowledge of how the system behaves, and following proper test
procedures. The cost for collecting and reporting data sometimes seems excessive, but
it is necessary to obtain the starting point for selecting and designing adequate control
equipment. Some control systems have demonstrated reliable control for essentially
every pollution control problem. On the other hand, problems with control equipment
can be associated with improper design, installation, operation, and maintenance, which
result in excessive costs and poor performance. Optimization of pollution control tech-
nology, by expanding research and development and providing adequate training, can
help to reduce some of the problems with control equipment. The latest information on
the air quality, environmental laws, control equipment, process systems, monitoring
technologies, and so forth can be obtained periodically from the Internet (57,65–66).

12. EXAMPLES
12.1. Example 1
Determine the heat content of an emission stream (gas stream 1) from a paper-coating
operation. Gas stream 1 has the following components: 100 ppmv of methane and 960
ppmv of toluene. Let subscripts 1 and 2 denote the methane and toluene components of
gas stream 1, respectively.
Solution
Equation (38) becomes
h = (0.01)[(y )(h ) + (y )(h )] (38)
e1 e1,1 e1,1 e1,2 e1,2
The ppmv for each gas is converted to % volume as follows:
Methane

y = (100 ppmv) (%/10,000 ppmv) = 0.0100%
e1,1
Toluene
y = (960 ppmv) (%/10,000 ppmv) = 0.0960%
e1,2
The heat content of each component is obtained from Table 6:

Methane: h = 882 Btu/scf
e1,1
Toluene: h = 4196 Btu/scf
e1,2