INCINERATION TUTORIAL
Submitting questions about incineration
An excerpt from the program INCINER.BAS on the disk to accompany BASIC
ENVIRONMENTAL ENGINEERING, by H. R. Bungay
Edited for the world wide web by George Pendleton and Anna Ruepp
This tutorial discusses incineration and the various types of incinerators
available according to present-day technology. By: Jennifer Lynn Reidy
December 16, 1988; Mark Owens May, 1990; James M. Waldron Dec., 1992
Incineration is an environmentally and technically superior method
of waste disposal, offering:
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RELIABILITY
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SAFETY
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EFFICIENCY
At the same time, it is highly controversial and expensive. In previous
decades, landfills were primarily used for waste disposal, allowing nature
to take its course, eventually reducing the end volume toxicity of the
wastes. However, because of increasingly stringent environmental regulations
concerning air quality, landfills, and groundwater contamination, along
with the decreasing availability of land for the encapsulation of wastes,
incineration has become the desired disposal method for municipalities
and industries.
Yet, even incineration technology is constantly undergoing revisions
in order to meet tougher environmental standards. These technological advances
include those that increase efficiency, and those that use emissions control
apparatus.
Incineration thermally decomposes matter through oxidation, thereby
reducing and minimizing the wastes, and destroying their toxicity. It can
be applied to industrial, municipal, and hazardous wastes, provided that
they contain organic material since it is primarily organic substances
that can undergo and sustain thermal degradation.
After incineration, wastes are converted to:
Depending on the composition of the initial waste, compounds containing:
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HALOGENS
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METALS
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NITROGEN
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SULFUR
may be produced. These compounds, along with CO, are deleterious to the
atmosphere, and highly regulated. Presently, the destruction efficiency
for these hazardous wastes must be 99.9999 %. Thus, to meet regulations,
incinerators need to be equipped with:
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AFTERBURNERS
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SCRUBBERS
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FILTRATION UNITS
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MEMBRANES
to provide secondary treatment for environmentally unsafe compounds, so
that they can be released to the atmosphere at suitable concentration levels.
Various types of incinerators are currently manufactured. The choice of
an incinerator depends on the wastes' combustibility and its characterization
as liquid, sludge, solid, or gas. The wastes' combustibility characteristics,
such as ignition temperature, flash point, and flammability limits determine
the necessary operating temperature, O2 concentration, and residence time
for greatest waste minimization. The proper incinerator types can then
be identified based on the waste specifications.
Types of incinerators