Module 6: Air Pollutants and Control Techniques - Dioxins and Furans -Practice Problems - Characteristics

Instructions:: Answer these questions on a sheet of paper and check your responses against those provided below.

#1

All dioxin and furan compounds contain the element:

: Answer: d. Chlorine; All dioxin and furan compounds contain the element chlorine. There can be as few as one or as many as eight chlorine atoms substituted on the dioxin or furan ring compound.

#2

True or False? Only specific dioxin and furan compounds are considered to be toxic.

: Answer: b. False; All dioxin and furan compounds are considered to be potentially toxic. Dioxin and furan compounds having from four to eight chlorine atoms are considered to be especially toxic.

#3: What are the two methods in which dioxin and furan compounds are calculated and regulated?

: Answer: Dioxin and furan compounds are calculated and regulated in the following two ways:

#4: Why is 2,3,7,8 tetrachlorinated dibenzo-p-dioxin used as the basis for the TEQ calculations?

: Answer: This congener is considered to be the most toxic of all of the dioxin and furan compounds.

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Dioxins and Furans:
Characteristics

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Dioxins and Furans:
Formation Mechanisms

Instructions:: Answer these questions on a sheet of paper and check your responses against those provided below.

#1

Dioxin and furan compound formation generally ____________ over the gas temperature range of 400 to 1000°F?

: Answer: a. Increases; Dioxin and furan compound formation usually increases over the gas temperature range of 400 to 1000°F.

#2

The formation mechanisms for dioxin and furan compounds depend on:

: Answer: d. a and c, only; The formation mechanisms for dioxin and furan compounds depend on appropriate gas temperatures and the availability of chlorinated precursor compounds.

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Dioxins and Furans:
Formation Mechanisms

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Dioxins and Furans:
Control Techniques

Instructions:: Answer these questions on a sheet of paper and check your responses against those provided below.

#1

Which minimum temperature is usually needed to destroy dioxin and furan compounds in waste incinerators?

: Answer: b. 1400°F; A temperature of 1400°F is usually needed to destroy dioxin and furan compounds in combustion processes.

: Answer: The formation mechanisms for dioxins and furans decrease to negligible rates when gas stream temperatures are held below approximately 400°F. Heat recovery equipment (economizers and air preheaters) and incinerator waste heat boilers are used to cool gas streams below this temperature before they reach the air pollution control system.

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Dioxins and Furans:
Control Techniques

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