dlp@akgua.UUCP (D.L. Philen [Dan]) (02/08/84)
On the subject of catalytic converters, let me add a
little more confusion. First, the use of catalytic
converters is not the cause of acid rain. Acid rain is
occurring because the EPA mandated lower stack emissions
from such companies as power plants. Since most ground
sampling is done near the stack, one solution to lower
emissions is to increase the length of the stack. Power
plant stacks of 200-500 feet are not uncommon. This has the
effect of injecting the power plant emissions (sulfur
oxides) higher into the troposphere. In the troposphere
there is a mixing layer. Air above this layer does not mix
(in general) with air below. This sulfur oxides injected
high into the troposphere combine with rain to form acid
rain. (The mixing layer is generally from 500 to 3000 feet.
The next time you fly notice when you take off that a few
minutes after takeoff you leave a layer of general haze and
enter an area of clearer air. This is the mixing layer.
Also on a day with many fluffy clouds, the bottom of the
cloud layer is near the mixing zone. When flying this is
also marked by a region of increased turbulence.)
On catalytic converters they convert the nitrogen
oxides (NO^2) to nitrogen and compounds which can not be
photochemically reacted to produce smog. It is to reduce
the nitrogen oxides (they produce smog) that the converters
were originally proposed. As a result of this massive
oxidation, one also oxidizes the sulfur. Since you don't
produce free sulfur, you produce sulfur oxides. The oxides
do not mix with the upper atmosphere to produce acid rain,
but do tend to be corrosive in their own right.
As an added "oh my gosh!" catalytic converters also
produce HCN (hydrogen cyanide). As we all remember from our
basic chemistry, HCN is produced in a reducing condition by
passing a hydrocarbon, and nitrogen, over a platinum
catalyst. Reducing conditions are EASILY encountered in
automobiles by 1) carb out of tune ie. too little air 2)
engine not warmed up ie. too much fuel or 3) going down hill
ie. engine warm, too much fuel and too little air. The
rotten eggs smell encountered is usually from S0^2 and all
the H2S should be oxidized to the oxide, unless of course
the engine is running the converter in a reducing condition.
This, by the way, is the commercial method for producing
HCN. Add to all this mess that trace amounts of lead poison
the platinum catalyst and you wonder if the catalysts are
worth all the trouble.shark@ihuxa.UUCP (Pete Inorio) (03/12/84)
I am thinking of having my catalytic converter replaced with by-pass
tubes. Does anyone know if it will improve my gas mileage and or do
any damage. It's a 1977 and the smell is disgusting! I'm not worried
about the fouling of my plugs, etc.
thanks
ihuxa!sharkshark@ihuxa.UUCP (Pete Inorio) (03/13/84)
Sorry, I guess no one out there knows anything about this subject.
grw@inmet.UUCP (03/16/84)
#R:ihuxa:-41700:inmet:2700062:000:363 inmet!grw Mar 15 11:34:00 1984 Get your engine adjusted, timing and mixture straightened out, and don't poison the air the rest of us breath (and violate Federal law) by removing your catalyst. If the power company near you took off it's scrubbers I bet you'd be on the citzens committee fighting to have them fined and thrown in jail. Pollution control is also a personal responsibility.
rctracy@uokvax.UUCP (03/18/84)
#R:ihuxa:-41700:uokvax:1100010:000:1485 uokvax!rctracy Mar 16 01:44:00 1984 I assume that you aren't worried about the legal aspects of replacing your catalytic converter with a "test tube"-type device, so we won't worry about that for the moment. Expect slightly better gas mileage, more power in passing (high-rev) situations, more frequent spark plug and oil changes (if you plan on using leaded regular), and considerable savings at the cash register when buying leaded regular instead of unleaded. Your actual savings will be reduced somewhat due to the increased maintenance I mentioned earlier. These are my experiences after performing the catalytic converter-ectomy you are contemplating. After putting more than 40,000 miles on a car that had 67,000 miles on it before removing the converter, the engine (Chevy 350) seems as healthy as ever. As for the legal aspects, this scene is changing rapidly. Oklahoma (as well as other states, perhaps) is considering legislation that would provide for checking for the presence of catalytic converters (on those cars originally equipped with one) during annual safety inspections. You would do well to remove your converter in a non-destructive fashion and save it for the day when the law will require you to put it back on. Flames from environmentalists will be cheerfully ignored. Driving behind a vehicle with a catalytic converter and getting one's eyes burned out from the fumes is more fun than one person should be allowed to have by him(her)self :-). --Bob Tracy ...!ctvax!uokvax!rctracy
rctracy@uokvax.UUCP (03/18/84)
#R:ihuxa:-41700:uokvax:1100012:000:574 uokvax!rctracy Mar 16 06:51:00 1984 One more thing concerning using leaded gasoline... Don't do it if your vehicle has one of those infernal "black boxes" under the hood monitoring and controlling the combustion process. The lead in the gasoline will foul several of the many sensors used by the computer, and you'll end up replacing them to get your vehicle running smoothly and/or predictably again! I don't think the particular vehicle in question (1977 model) is recent enough to fall into this category. (My 1976 Camaro doesn't have one of these computers). --Bob Tracy ...!ctvax!uokvax!rctracy
grw@inmet.UUCP (03/22/84)
#R:ihuxa:-41700:inmet:2700066:000:718 inmet!grw Mar 20 12:10:00 1984 I don't consider my previous response a flame. The biggest problem in air pollution control these days is the growing number of illegally modified autos. The long term effects of high concentrations of the pollutants autos produce (and which are significantly reduced in a properly adjusted car with a converter) are known and were behind the Clean Air Act which led to the converters in the first place. If there was some other atmosphere people who don't concern themselves with the air they breath could polute I would have no objection to them polluting it and living there, however.... -- Gary Wasserman ...harpo!inmet!grw ...hplabs!sri-unix!cca!ima!inmet!grw ...yale-comix!ima!inmet!grw
stan@clyde.UUCP (Stan King) (03/23/84)
I disagree. The biggest problem with air pollution control now is diesel vehicles. In all fairness to the trucking population, I have seen many more poorly-tuned diesel cars. However, even the well-tuned diesel produces about 100 times more particulate emissions than do gasoline engines. That's the cost of the fuel economy. Stan King phone: 201-386-7433 Bell Labs, Whippany, NJ Cornet: 8+232-7433 room 2A-111 uucp: clyde!stan