William Kovarik
Radford University
and
Matthew E. Hermes
Kennesaw State University

 

Fuels and Society: C. How Lead was Finally Removed from Gasoline

A History of Decisions that Affects Today's Gasoline Price and Supply

1. Nitrogen Oxides as Pollutants
2. Catalytic Converters
3. Catalytic Converter Chemistry
4. Phase-Out of Lead
5. Impact on Fuels
6. Fuel Refinery Chemistry
7. Reformulated Gasolines
8. Back to Alcohol
9. MTBE
10. MTBE Chemistry
11. Organics in Water
12. MTBE Pollution
13. Corporate/Government Decisions - 1990's
14. Impact on Auto Manufacturers

This unit links the physical and chemical properties of atmospheric pollutants and tetraethyllead to the decisions to introduce the catalytic converter.


You will learn about the chemistry of the pollutants we call smog


You will understand the chemical catalysis and how the catalytic converter changed fuels and engines.


Analysis of alternate strategies resulted in introduction of MTBE and its new set of pollution problems.


What will you do to resolve the future of automotive fuel and engine design.

 
The Facts: From the mid 1920's until the mid 1980's motor gasoline fuel contained an additive, tetraethyllead, that improved fuel performance by preventing preignition in the cylinders of the engine. Preignition resulted in damaging and efficiency and power reducing knocking. 

Tetraethyllead is a toxic liquid that killed more than 40 chemical workers during its early development and manufacturing. Nevertheless, motor companies, oil companies and the government authorized the manufacture, distribution and use of tetraethyllead in gasoline throughout the world.

Pb(C2H5)4
Tetraethyllead (TEL)


Atlanta Today

In the late 1960's new anti pollution initiatives made the automotive industry look at better ways to reduce nitrogen oxides and carbon monoxide effluents from the automobile engine. The nitrogen oxides were at the heart of a problem we could see - hte brown haze that hung over the cities - and that we can still see today!
The Solution: A small canister called the catalytic converter was installed in US automobiles beginning in 1976. This device consisted of heavy metal catalysts imbedded on a ceramic support. The converter was installed in the engine exhaust. The converter chemistry was such that the converter caused oxidation of CO and reversal of the reaction producing nitrogen oxides.

New Challenge: But lead in the exhaust stream - the residues of TEL that had been added to the gasoline to improve performance - immediately deactivated the converter catalyst. The combination of the catalytic converter and leaded gasoline did not work. One of them had to go, and it was the TEL!!



1979 Chevrolet Camaro - Early in the no-lead gasoline era.

The Questions: So the fuel and automobile companies now faced the same challenge they faced in the 1920's - how to develop a compatible system of fuel and automobile engine that would perform efficiently.

They reformulated, developed new additives and faced issues of cost and supply. Go through the units outlined in the concept map that describe fuel reformulation, the reintroduction of alcohol and the chemistry of a new octane enhancer, MTBE and the pollution attributed to MTBE.

CH3OC(CH3)3
MTBE

End with a case discussion looking ahead to the future of fuels and engines.

Begin with the unit generation of nitrogen oxides as pollutants click on any area of the concept map below.

College of Science and Mathematics
Kennesaw State University
1000 Chastain Rd.
Kennesaw, GA 30114
770-423-6160
 
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