Industrial Waste Disposal by Solar
Evaporation
J. L. RAGAN, Projects Development Superintendent
Celanese Fibers Company
Rock Hill, South Carolina
R. H. MAURER, Chemical Engineer
Celanese Chemical Company
Bishop, Texas
The purpose of this discussion is to outline some of the factors which must be
considered in the design and operation of a solar evaporation system for industrial
waste disposal and to show how these factors have been combined to give an economical waste disposal system. As background information, the Chemcel Plant of
the Celanese Chemical Company, located near Bishop, Texas, produces about 50
different industrial organic chemicals of which formaldehyde, acetaldehyde,
acetic acid, methanol, and acetone are typical. These chemicals are produced
by the partial oxidation of propane with air and oxygen under controlled conditions
of temperature and pressure. The plant has been in operation for about 18 years
and has continued to expand and diversify at a rapid rate during the past 10 years.
In producing these chemicals a process waste is produced amounting to about
500 gpm of water containing traces of most of the major products, especially formaldehyde, plus various aldehyde and ketone polymers and other compounds
which cannot be economically recovered. Because of these contaminants the
the waste cannot be released into public waters.
Solar evaporation depends mainly on solar energy to supply the latent heat of
evaporation required to evaporate the water. Practically all of the energy is received from the direct rays of the sun with only a minor amount being received
from warm air blowing across the surface of the water. Since solar energy received
throughout most of the Southwest is roughly the same depending on the cloudiness,
successful waste disposal by means of solar evaporation depends primarily on
limited rainfall. To be more specific, the gross annual evaporation in most areas
of Texas is in the range of 44 to 66 in. /yr. We feel that in areas where this gross
evaporation exceeds rainfall by 20 in. or more per year, solar evaporation is a
practical means of waste disposal.
DESIGN CRITERIA
In considering the design of a disposal system for a new plant, it is first necessary to determine roughly if solar evaporation is feasible. This can be done
qualitatively by reference to a chart such as shown in Figure 1, which was published by the Natural Resources Planning Board. This particular chart shows approximate net evaporation rates for the Southwest. These values range from a net
evaporation of 70 in. /yr in the El Paso-Big Bend area to minus 20 in. /yr in the
Louisiana, Mississippi, Alabama coastal area. As stated before, at net evaporation
rates below 20 in. /yr solar evaporation becomes questionable as a means of waste
disposal although this is flexible and will depend on a number of other factors such
as land cost and waste volume.
If a rough check indicates that solar evaporation is feasible, more detailed
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