Encyclopedia of Environmental Science and Engineering, Volume I and II

Part 2. Major Air Pollution Sources (continued)

Mineral products industry Nature of activity Type of air pollution problems

TEREPHTHALIC ACID Terephthalic acid is an intermediate in the

production of polyethylene terephthalate,

which is used in polyester films and other

miscellaneous products and by oxidizing

paraxylene by nitric acid.

The NO in the off gas from the reactor is the major air

contaminant from the manufacture of terephthalic

acid.

STONE QUARRYING AND

PROCESSING

Rock and gravel products are looosened by

drilling and blasting from their deposit

beds and removed with the use of heavy

equipment. Further processing includes

crushing, regrinding, and removal of fines.

Dust emissions occur from many operations in stone

quarrying and processing.

Petroleum industry Nature of activity Type of air pollution problems

PETROLEUM REFINING The operations of a petroleum refinery can

be divided into four major steps:

separation, conversion, treating, and

blending. The crude oil is first separated

into selected fractions (e.g., gasoline,

kerosine, fuel oil, etc.). Some of the less

valuable products such as heavy naphtha,

are converted to products with a greater

sale value such as gasoline. This is done

by splitting, uniting, or rearranging the

original molecules. The final step is the

blending of the refined base stocks with

each other and various additives to meet

final product specifications.

The major pollutants emitted are sulfur oxides, nitrogen

oxides, hydrocarbons, carbon monoxide and

malodorons materials. Other emissions of lesser

importance include particulates, aldehydes,

ammonia, and organic acids. Most of the above

mentioned emissions come from boiling process

heaters, and catalytic cracking unit regenerators.

160,000

140,000

120,000

100,000

80,000

60,000

40,000

20,000

0

TRI air emissions in thousand tons/year

Toluene Methanol1,1,1TrichloroethaneXylene(mixed Iso) MEK Chlorine DichloromethaneCarbon DisulfideHydrochloric AcidTrichloroethylene

1988 1989 1990 1991 1992 1993

FIGURE 4 Top 10 Hazardous Air Pollutants—1988 Basis.

AIR POLLUTION SOURCES 111

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