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sparkgap
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Actually, that's part of the reason why catalytic converters are rendered useless if the gasoline hasn't been "sweetened" (i.e.,
the sulfur containing compounds haven't been removed in the petroleum).
I don't remember lead being used as a catalytic poison.
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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neutrino
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Both are poisons.
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Taaie-Neuskoek
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hmm, I found other info, from here
I quote:
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Q. What is the effect of sulphur-free fuel on exhaust emissions?
A: Exhaust emissions will be lower – particularly from catalyst-equipped cars. Sulphur in petrol and diesel fuel has a major negative impact on
catalyst performance, especially for NOx catalysts and adsorbers. The effect of sulphur on catalyst performance becomes more critical as lower
tailpipe emissions are targeted for the very low emission levels required in future. Sulphur strongly competes against pollutants for
“space” on the catalyst surface limiting the efficiency of catalyst systems to convert pollutants at any sulphur concentration – so the lower
the sulphur levels in fuels the better the catalyst performance that can be obtained. The conversion of sulphur to a sulphate aerosol can cause net
increases in particulate emission.
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So here it states that sulphur doesn't kill the catalist, but will just do what we want, convert it!
Never argue with idiots, they drag you down their level and beat you with experience.
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Mr. Wizard
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So does Sulfur does 'poison' the catalytic properties of Platinum by giving Sulfur Dioxide ->SO3 preference over CO>CO2 in oxidation?
Everything is relative I guess. I did read somewhere that Rhodium was incorporated in the catalytic converters to reduce NOx emissions. I've
also read that Pb contaminated catalytic converters can be brought back by strong heating to drive out the Pb. Catalytic convertors would make an
interesting thread, as far as usefulness and valuable materials.
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12AX7
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| Quote: | | Originally posted by Mr. Wizard and valuable materials. |
Actually they make them so well there's only about $50 worth of PGM in them, IIRC.  You could slice them up though, with a diamond (lapidary) saw preferably, to get more managable catalytic pieces than the entire unit
(not to mention free of the corrodable steel casing  ).
Tim
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Fleaker
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When I get around to extracting all of the PGMs out of the catalytic converters I already have, expect a full write-up I should like to add that there are higher concentrations of PGMs in older catalytic
converters, newer ones (past 1992 contain less). Interestingly enough, cat. converters made in the early 80s (between mid 82' and early 84 use a
large amount of rhodium which is a valuable metal at nearly 2x the price of platinum per troy ounce.
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Taaie-Neuskoek
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I found an article about the prevention of sulpur poisening (see att), but even they do not explain WHY there is sulphur poisening, everybody seems to
mention it, but why...??
Does anyone has acces to the references they give, I would be interested in ref. nr 3, as they refer to that article when they say something about the
sulphur poisening.
Hughes, T. R., Buss,W. C., Tamm, P.W., and Jacobson, R. L., in “Proc.
7th Intern. Conf.” (Murakami, et al. Eds.), p. 725. Kodansha, Tokyo,
1986.
Attachment: catalist sulphur poisening.pdf (356kB)
This file has been downloaded 907 times
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Hermes_Trismegistus
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I have a suggestion that eliminates the issue of molten sulfur handling, and addresses purification.
If the sulfur were reacted(easily) with powdered iron, (available from the handwarmer packets) you'd get Iron Sulfide.
Iron sulfide is more easily processed and purified than the plastic/powdered sulfur.
It is quite brittle and could be powdered in a ball mill.
It could be washed with various solvents, and acids in order to get it ultrapure and keep from contaminating your catalyst.
The powder could then be burnt in oxygen to form sulfur dioxide and iron oxide (rust) (this reaction is exothermic, and self sustaining) and the
resultant gases run through a pipe and there catalysed with reasonably cheap vanadium pentoxide (available from pottery suppliers)
I know this reaction is feasible because it was commonly used during the Big Wars.
Now, we just use the hydrogen sulfide gas that comes up with the natural gas out of the wells to make the acid industrially. (the h2s is surplus, and
they have to remove it anyway...)
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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Eclectic
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Has anyone tried using a small jet of oxygen in a flask of sulfur with the flame impinging on the molten surface? Maybe an afterburner would be
needed to combust excess volatized sulfur?
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darkflame89
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About the iron sulfide
Well, there appears to be a way for iron fillings to react with powdered sulfur. The documentation for it is scant and I do not know whether it is
truth, but here goes.
I found this accidentally
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Mix it with iron filings and then wet the mixture with water and
wait. After an induction period the materials will react to form
iron sulfide with sufficient heat evolution to cause the mass to
bubbles and steam. You can make a nifty volcano by running the
reaction under a pile of dirt if you are young enough to enjoy
such play.
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It was found in yarchive.net and a similar discription found in Lateral Science. If true, iron sulfide could be made without the need to heating the
mixture of iron and sulfur.
[Edited on 25-9-2005 by darkflame89]
Ignis ubique latet, naturam amplectitur omnem.
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oukao
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| Quote: | Originally posted by Rosco Bodine
An idea occurred to me as I was reading about the film type sulfur burner and considering ways of improvising a burner
which would operate according to the same principle , without needing a refractory lined furnace . Everyone is familiar with the flat spiral coil
heating elements used in hotplates and I thought
that a thin ~ 2mm sheet of stainless steel could be overlayed with fine mesh stainless filter cloth and securely fastened
with stainless steel pop rivets and stainless washers positioned so the rivets
pass through the gaps in the heating element into backing plate washers on
the underside of the heating element .
As the pop rivets are set , everything will
be pulled snugly together as layers of a sandwiched assembly . Such an element
could be electrically heated by a rate controller until it reaches a temperature
where sulfur dripped onto its hot surface
will inflame . The element could be tilted
to provide the spreading effect of a film type burner to the burning molten sulfur
which would spread across its surface by
gravity flow . As the element gets hotter
from the burning sulfur , the supplemental
electrical heating could be reduced to a
level which maintains a smooth burning at
the particular flow rate of sulfur being supplied . The rough absorbent surface
provided by the stainless filter screen should function in the same way as would
the porous surface of refractory brick in
a regular furnace . I think if I was going
to build a sulfur burner this is probably the
approach I would try first . There are cone shaped ceramic heating elements made for use with parabolic refectors ,
which have a threaded contact base so
they can screw into a socket for a light bulb . The ceramic cone has a nichrome coil wrapped around the outside in a spiral groove . Perhaps a
heating element
of this sort could also be adapted for use
as a sulfur burner . |
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Texium
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Thread Moved
19-11-2023 at 11:17 |
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