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Module 6: Air Pollutants and Control Techniques - Incompletely Oxidized Compounds - Characteristics
Lesson Material
Practice Problems
Objective
- Describe the basic characteristics of incompletely oxidized organic compounds and carbon dioxide.
Boilers, gas turbines, and waste incinerators are major sources of incompletely oxidized organic compounds and carbon monoxide.
Incompletely oxidized organic compounds are a large category of compounds. They are generally grouped together because they form simultaneously when combustion conditions are unfavorable. There may be several compounds present, each of which is at a relatively low concentration. However, collectively, the concentration of the partially oxidized compounds can be substantial. These compounds include polycyclic aromatic compounds, unsaturated compounds, aldehydes, and organic acids.
Some of these compounds have high molecular weights and low vapor pressures. These materials condense quickly on the surfaces of particles in the gas stream (heterogeneous nucleation). Other partially oxidized compounds have moderate to high vapor pressures, and they remain in the gas phase.
Carbon monoxide is another partially oxidized compound that results from incomplete combustion. It forms when the gas temperature and/or gas oxygen concentration is insufficient to cause oxidation of carbon monoxide to carbon dioxide as shown in the reaction below.
Carbon monoxide is a relatively stable compound. This reaction is very slow at gas temperatures less than approximately 1800°F. It is more difficult to complete the oxidation of CO to CO2 than to complete the oxidation of the partially oxidized organic compounds.
Figure 1 shows major sources of carbon monoxide,
with automobiles and other mobile sources being the primary emitters of
this criteria pollutant. The residential category includes wood burning
stoves and fireplaces; while the industrial category consists of metals
processing plants in addition to incinerators and boilers.
Practice Problems
Incompletely Oxidized Compounds - Characteristics
- Instructions:
- Complete the Practice Problems before proceeding to the next section. Click on the button below.