Sciencemadness Discussion Board - Sulfur Burner Simple Idea

Sulfur Burner Simple Idea

Rosco Bodine - 20-11-2004 at 08:44

Having read through a couple of threads where it appears there is a struggle with the design difficulty for burning molten sulfur , there is an idea I wish to share .

Consider that liquids maintain a common level in two reservoirs whose bottoms are
joined through a connecting tube . The principle is used in the liquid levels which
are used by concrete workers , to set the
forms at equal height before pouring a large concrete slab . Colored water fills
a continuous length of plastic tubing having each end fitted to the bottom of
a transparent buret , so the level of the
colored liquid can be observed in each buret , even if they are a hundred meters
apart , the level of the liquid in each will
correspond to the level in the distant indicator .

It doesn't matter what the diameter or volume of each reservoir may be , the liquid level is strictly related to depth ,
and the equalization of pressure caused
by gravity acting upon the column height
of the liquid , balanced one against the other .

Now suppose the liquid was a fuel and one reservoir was a large diameter but shallow vessel , and the other reservoir
was a small diameter deeper vessel having a burner wick , the lower portion
of which was kept wetted by the constant
level of liquid maintained from the larger
diameter reservoir at a distance . The small burner would be kept supplied with liquid fuel from the larger diameter distant
reservoir , whose level would drop very slowly , and could be replenished to maintain a certain level , or could simply be raised in height gradually to maintain
a corresponding liquid level in the burner .

The wick material for burning sulfur could
be a rolled section of stainless steel gauze
filter mesh , or fiber glass cloth , or a lamination of the two materials rolled into
a cylinder and fitted snugly into the burner
"buret" which enters the bottom of a combustion chamber . An external reservoir could be made from an electric fry pan with a thermostatic control , fitted
with a bottom drain to a stainless steel
connecting tube to the adjacent burner and combustion chamber . The connecting
tube could be supplementally heated to
keep the fuel molten in the travel path from the reservoir to the burner . Everything could be insulated with fiberglass batting to keep the power requirement low .

At automotive suppliers there is sold a braided sleeve material made of fine stainless steel wire woven into a tube which can be slid over rubber hoses as
an armor to reenforce and protect hoses
from abrasion . Also they sell fiberglass "tape" for use as a muffler bandage , or body repair item . Wound tightly together and secured with fine stainless wire from a fishing tackle store ,
a wick could be made , which would have
the diameter to snugly press fit inside of
a stainless steel tube . The tube itself could function as the local reservoir for the
burner wick . The size tube I have in mind
is something about 10 to 13 mm ID , but the principle could be used for any size upwards of whatever minimum is found would provide an efficient sized flame ,
and the SO2 output desired . Such a burner could be assembled using OTC materials , pipe and tubing fittings , ect .

Actually a wick isn't strictly required anyway , a small open thimble can be used as the burner and the surface of the molten sulfur burned directly . The heat
from the flame will heat the molten sulfur
in the thimble to boiling and the vapors
will burn without any wick . Molten sulfur
is quite easily flammable . A small chunk of lava rock or even brick or pottery shard
dropped into the thimble could serve as
a sort of wick if one is needed to stabilize
the flame .

If the thimble containing the pool of burning sulfur was shaped like a funnel ,
then the surface area of the burning sulfur
could be increased or decreased by raising
or lowering the level , thus controlling the
output of the burner . Along with the
volume of air being supplied to the burner , and how much insulation is applied to the combustion chamber and
its exhaust path , the temperature of the
SO2 and air mixture exiting the combustion chamber may be regulated to
whatever is optimum for further oxidation
to SO3 by the catalyst . For a catalyst chamber , again I would suggest stainless steel , perhaps a half meter length of automotive exhaust pipe ~ 50 mm diameter . The idea for a catalyst carrier would be small chips of broken terra cotta in a layer on fine mesh stainless screen rolled into a cylinder and
inserted into the tube . The housing could
be preheated with a burner when initiating the reaction , and thereafter the
temperature of the catalyser section could
be regulated by the flow rate from the burner , and by applying or removing insulation to conserve or radiate the exotherm of the reaction .

Such a sulfur burner and combustion chamber could of course also be used as
a source of SO2 for the chamber process .

[Edited on 20-11-2004 by Rosco Bodine]

Marvin - 21-11-2004 at 00:56

That seems to me to be an odd thing to call 'simple'.

Do you have a problem with the sulphur candle idea? Glass or ceramic wool wick, kept straight with a metal wire and submerged in sulphur. When set, light, feed in air and burns like a candle.

garage chemist - 21-11-2004 at 01:47

How do you keep all the sulfur in the tubing liquid?
Also, be aware that molten sulfur has several states of different properties, depending on temperature. When sulfur is molten, it has a low viscosity at first. But then, it thickens on further heating, to the point where you can turn over the vessel without spilling it. It becomes less viscous again on further heating, but that temperature region is close to its boiling point.
Temperature control would be very critical in such a device.
A sulfur candle seems better, but you still need to find/make a suitable container where it can burn inside and where you can pump in air and extract SO2.

Chimney design?

chemoleo - 21-11-2004 at 02:08

Couldn't you work it out like a chimney?
I.e. a reservoir, with the wick sitting in the middle. The reservoir has to be quite large to avoid having to refill all the time.
At the surface of the sulphur one would place an air inlet, which would feed the flame directly. The heat generated by the flame would lead to an upward current of SO2 and gasses, which would lead out through the chimney. This would then be fed into the V2O5 catalyst (with an additional air inlet beyond the chimney), to be oxidised to SO3 directly.
If the updraft is not enough (which is likely, as a lack of decent pressure), one could alternatively feed in the air with an aquarium pump, you know those that bubble air into the aquarium.
Then constant air flow & burning rate is ensured (by restricting O2 addition by the input rate), which is probably desirable for a continuous flow design.

BTW I successfully used an aquarium pump to generate NO2 by blowing air through conc ammonia, which was then dried on CaO/NaOH, and fed into a glass tube containing hammered (flat) platinum wire. The heat of the reaction kept the Pt wire red hot, without an outside heat source, and I managed to get some HNO3 in the end (like a couple of ml).
Trouble is of course that this isn't a very efficient process to do at home...

neutrino - 21-11-2004 at 07:29

To generate SO3 from the candle, would it be possible to simply hold a V2O5-encrusted mesh above the flame? The heat of the candle would keep the mesh hot, while the exhaust (SO2

would react with oxygen and form SO3. To use it, you’d put it in a large container with air and some water, light the candle, seal the container, then wait for the flame to go out and all of the SO3 to hydrolysize. Then simply open the container, replace the air, and relight.

Rosco Bodine - 21-11-2004 at 09:13

If you want to produce test tube quantities of sulfuric acid , use a candle .

If you want usable quantities of product then you are going to need a burner of some sort that is controllable in its output , and the scheme I suggest is
the simplest workable method I can imagine . A small thermostat controlled
electric frypan could have a hole drilled
through its bottom , and a pipe threaded
flange attached with four screws . A convoluted flexible metal tube is connected as a drain and run across to
the adjacent combustion chamber . The
tube is spiral wrapped with a insulated
heating element cord and fiberglass ribbon to keep the sulfur molten in the line . A thermocouple on this line , and
on the combustion chamber outlet , and on the catalyst chamber would be needed
for monitoring and controlling the process . A floating ball airflow volume indicator would be good too on the feed air to the combustion chamber . These
sorts of basic controls would be required
to run such an apparatus at any reasonable efficiency .

Something simpler that may work as an
alternative having lesser controllability ,
is to use an old stainless steel beer keg
as a combustion chamber . Cut an access
opening in the side and then make a sealable door from the cutout piece so
it can be fastened back in place over the opening . Put a potful of sulfur in through
the hatch and set it afire , replace the hatch cover , and feed in the air for sustaining the combustion . Extra sulfur
could be added through a chute from outside . Of course there would be difficulty in regulating the process closely .
There is more involved than simply getting sulfur to burn and deliver SO2
from its burning . The trick required is
for that burning to be regulated so that
a stoichiometry within reason is maintained of excess air and SO2 in admixture , and at the right temperature and flow rate to be subsequently useful for conversion to SO3 . Anybody can
"dumb burn" sulfur "in a can" , and then find difficulty in making use of gases they
have coming out of that can , unless it
has the desired ratio of O2 to SO2 at the right temperature for further conversion .

Marvin - 21-11-2004 at 18:08

"If you want to produce test tube quantities of sulfuric acid , use a candle "

Maybe you have a different idea of the candle than I did, but in terms of size I was thinking of a a multigallon container and wick like a rolled up T shirt. The amount of SO2 you make would depend on how quickly you feed in air or oxygen. The output would not be totally O2 free, but then it wouldnt need to be, it just has to be stable in the amount.

The problem I have with the 'pot' idea, is that sulphur in my experience doesnt burn like petrol, it burns more like wax. I'm sure it is possible to have lots of tubing kept hot and to feed this into a a proper oil type burner but I question the need. You dont have to control the amount of sulphur going into the burner with a candle, it melts as is needed, you get a flame as big or as small as the airflow allows.

[Edited on 22-11-2004 by Marvin]

Rosco Bodine - 21-11-2004 at 20:03

Take a look on the following page for a couple of ideas about sulfur candles .
I was thinking more in terms of the first
example as being a "candle" and thinking
more of the second example as a "lamp"
or burner , but I suppose the terminology
is ambiguous , and creates confusion .

http://website.lineone.net/~dave.cushman/fumcandle.html

I still believe that a funnel shaped thimble
with a chunk of lava rock sitting in a pool of molten sulfur would be the optimum in
a controllable output burner , realizing that kilos of sulfur will be burned to produce liters of oleum . And this is only one difficulty to be managed , as the
SO3 will be produced as a microfine fog
which will defy condensation as if one was
attempting to liquify smoke . Some sort of
sequence of glass fiber filters and drains
will be required to accumulate the product without loss . Perhaps a long coil condenser would centrifuge and coalesce
the fog effectively .

Sulfur melts at about 113 C and has its lowest viscosity at 150 C . In industrial practice sulfur burners burn the sulfur directly from a pool of the liquid , using a cyclonic flow of air and high temperatures to reduce any escape of uncombusted fumes of sulfur as sublimate dust . The
SO2 burners when used for production of
SO2 as the desired end product are operated at 1000 C to 1200 C combustion chamber temperature and the gases resulting from air fed combustion analyze about 20% SO2 content . But those conditions are to minimize any side reaction producing SO3 directly as a byproduct . For our purposes to produce
as much SO3 as possible , the combustion
chamber temperature should be much lower in the range of 500 C to 700 C , with
much greater amount of air and lower concentration of SO2 in the gases from combustion .

There is another efficient method of cleanly burning liquid sulfur at a controlled rate which involves flowing the melted sulfur onto a sloped heated refractory brick , the burning sulfur spreads out in a film as it flows by gravity across the hot surface . This method would have the simplicity of being a gravity feed system , easily adaptable to small scale .
See this link for advantages of a film type sulfur burner .

http://cptech.dost.gov.ph/etc-0070-FD039.php

An improvised burner based on the film burner principle has merits worth considering .

[Edited on 22-11-2004 by Rosco Bodine]

Marvin - 22-11-2004 at 01:41

In the second type only a small amount of the fuel melts and there are plenty of examples of candles with plastic outer containers. I should have explained better, but this has been covered in other posts here.

If you want to collect solid SO3 after cooling, may I suggest electrostatic precipitation. A home ioniser would probably be good enough for power into a few sharp points on the inside.

If only producing sulphuric acid or oleum is important the best way would probably be to bubble the product through concentrated sulphuric acid (water cannot be used), diluting it as needed.

Rosco Bodine - 22-11-2004 at 06:56

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 .

BrAiNFeVeR - 29-11-2004 at 08:14

A H2SO4 reactor I've been playing with in my head:

With the constant underpressure from the vaccuum source and the open atm at the burner end, the chance of suckback effect is reduced to 0.

The problems I see:
-H2O is allready coming in with the O2, which will cut the V2O5 catalyst life in half.
-Lower pressure => lower reaction rate => less SO3, considerable amounts of SO2 ...
-The SO2 + SO3 must be cooled before entering the H2O ofcourse

[Edited on 29-11-2004 by BrAiNFeVeR]

Marvin - 30-11-2004 at 01:14

Dont absorb with H2O, SO3 forms a mist. Absorb with conc sulphuric acid then dilute it afterwards.

The low pressure in the absorbing flask, asuming it is much below atmospheric cripples the absorption as it gives a given amount of gas a much greater volume.

It looks to me by not enclosing the burner you will lose a lot of SO2 to the enviroment.

BrAiNFeVeR - 1-12-2004 at 02:06

That entirely depends on the volume of gas the vaccuum pump gets, and the amount of sulfur burned.
A little SO2 loss will be the least of my problems ...

The pressure in the absorbtion flask will be determined by the air resistance in the catalyst tube and the gas transport tubing.
Besides, why would this be a crippling factor?
More volume of gas => more contact area, right?

And ofcourse the blue liquid in the flask is H2SO4 >85% going to 120% (H2SO4.SO3).

Ofcourse, main problems here are moisture in the air (better use pure O2 perhaps), and cooling of the absorbtion flask ...

Taaie-Neuskoek - 1-12-2004 at 03:53

I wonder how powerfull the suction is after the catalyst and the receiving flask, I think you need a rather strong pump.
Blowing air instead of sucking looks to me a better alternative, you can also improve the burning rate with it.

If you want to enlarge the contact surface, then buy a watertrap with a bubbel-speader, I don't know the name of it. Use this in combination with magnetic stirring, and you'll have a large contact surface.

Cooling can be done by ice I guess.

BrAiNFeVeR - 1-12-2004 at 07:59

I have a refrigerator pump that can pull 95% vaccuum (50mbar abs), and the debit (a few liters/minute) is just enough for such a lab-scale experiment

I'm going to assume that the SO3 is willing enough to bind itself to any free H2O it can find, so I won't have to buy special bubble spreaders and the like.

Cooling by ice is not a very energy efficiënt process ... maximum temperature of the H2SO4.SO3 should be high enough to transport the energy by evaporation of water. With some setup to create a high air velocity over a large surface of warm/hot (40-90°C) water.

Marvin - 1-12-2004 at 10:30

For the same bubbler contact area is broadly fixed. Within certain boundries more gas flow equates to bigger bubbles, so a smaller surface area per unit volume. What can also change is the rate of gas flow over a 'surface' (through the solution) and with increased rate of gas flow decreased contact *time* and so less of a reaction.

Reducing the pressure is the same as diluting the gas with something inert.

[Edited on 1-12-2004 by Marvin]

frogfot - 18-8-2005 at 02:06

Tested a successfull sulfur burner couple of days ago (just realised that this design was already proposed by BrAiNFeVeR)

Heres a pic from the first test:

The burner is basically made from tin cans. Theres a cup (cut from an iron can) where the sulfur is placed. The cup is 3,5 cm in heigth and 7,5 cm in diameter. This is covered by a "chimney", composed of two tin cans connected with teflon tape. The chimney is connected by a rubber hose to three bubblers with absorbing solution (in that case Na2CO3), then to a filter with glass wool and finally to a madress pump.

Since S burned in air produces above 2% SO3 (according to one book) in seconds of operation the setup was filled with fog of H2SO4.. The glasswool filter removed all fog..
So in this recent test I used following setup:

Burner connected to two 96% H2SO4 (boiled battery acid) bubblers, followed by 2 bubblers with NaOH solution, a glasswool filter and the pump. This made much less fog.

Since there was 4 bubblers, the air flow was pretty low and sulfur burned slowly. So after an hour of operation I changed the madress pump to an aspirator which increased the burnrate. This way the reaction with about 40 g NaOH was compleated on additional 30 min.

The pH in first NaOH bubbler was about 5,5 and it was neutrolised by NaOH solution from second bubbler. A half of this resulting solution was then boiled down and treated by ethanol. This gave 31g white crystalline Na2SO3. So there was totally 62g product.

The fun thing is, there was nearly no sulfur sublimarion noted. There was some sulfur in pipe of the first H2SO4 bubbler but this shouldn't pose any problem since sulfur particles was loose and they was in increadibly low amount

I just realised that some of the obtained sulfite may contain crystall water.. It said to be that at lower temps Na2SO3 crystallises with 7 H2O. But about half of the prod crystallised at boiling temp of the solution.. I dunno if alcohol precipitates the anhydrous stuff..

Any idea if one can dry the Na2SO3*7H2O at high temps? I know that it suppose to lose water at 150*C, but what about decomposition to SO2..?

I just want to calculate the efficiency of the absorber train...

EDIT: Forgot to mention one problem.. On burning of sulfur it produced somekind of black lyer on top that seemed to reduce the burning... Any idea what this may be, what kind of impurity maybe..? It could be removed mechanically from time to time, but this would be annoying..
Btw, my sulfur dissolves without residue in xylene..

[Edited on 18-8-2005 by frogfot]

12AX7 - 18-8-2005 at 09:37

Brauer on sulfur mentions something about hydrocarbons present, the only way to remove is heat to break them down, any solvent just dissolves and recrystallizes both at the same time. Mind that Brauer is going on about 5n purity...

Tim

frogfot - 19-8-2005 at 12:58

Shouldn't hydrocarbons just burn..
In worst case one could stir the sulfur from time to time to remove the fire repellant layer..

Duster - 23-8-2005 at 19:45

I hope this isnt considered bringing up a dead topic... But I was thinking...

For whatever reason I have been wondering about SO3 recently... I cant actually preform ANY reaction until I get back home in a (long) while, but I put it down on paper so I dont forget.

In any case, I remember in a seperate thread (I think its a sticky actually) about the lead chamber process but using KNO3 and Sulfur in a plastic container and what not... Well I was thinking...

An issue that seems to be comming up is a way to replenish the sulfur supply... While I havent completly figured this out myself, I took the next logical step and thought of a way to hold a whole lot of sulfur...

The soda can tower gave me an idea... Why couldnt a person have a rod of metal (anything with a melting point above whatever sulfur burns at, which shouldnt be hard to find) and drill a hole in it... Then one could mix sulfur and KNO3 (or other oxidizer) and compress it in this hollowed out rod...

Surely the metal would contain the reaction, and having it pressed would keep the burn rate from getting too great... This could be made as tall as needed for as much sulfur to burn as reuired...

I dont know how diameteres would affect things, of course the larger the hole the more surface area and the slower the burn rate...

Really I wouldnt even need to be a rod, it could be any block of a material that could resisit the reaction temps and products...

If corrosion is an issue, you could plate the metal with a compound perhaps, or maybe the issue overall wouldnt be big.

Just brainstorming...

12AX7 - 23-8-2005 at 21:56

Just ram/press it into a paper wrapper like a sparkler. (Don't know if you'll mind the cellulose combustion products..) It's still wasteful of KNO3, this just doesn't make sense to me, specially since sulfur burns in air.

Sulfur candle, ok. Concentrated SO2, well you can get better by placing a tube over the flame so it's drawn into it like a narrow chimney. Fully concentrated, I don't see why you couldn't set up some sulfur refluxing (ok, wasteful of excess heating source sure) above the ignition temperature and flow in a rich-burning amount of O2 or air (i.e., stoichiometrically less than the amount of S vapor available).

Not the exact thread to be mentioning it but for catalytic SO2 > '3 burning, or any catalysis for that matter, has anyone *ever* thought about an old dead automobile catalytic converter? Available in all sorts of sizes and even a pretty bad (free) one is bound to have more than enough PGM on it to suffice, after burning off the soot or chipping out melted ceramic to get it operable.

I have one and, after heating the honeycomb up to orange heat with my propane burner, I can shut it off and turn it back on. Hotspots light up and it burns the gas/air mixture flamelessly.

Tim

Duster - 24-8-2005 at 20:55

I was under the impression SO2 had to be strongly oxidized (as in the lead chamber process) to form SO3. If that is not that case, and fresh air alone can do it, then either way it should work... Maybe anyway...

Taaie-Neuskoek - 25-8-2005 at 04:20

Quote:

Not the exact thread to be mentioning it but for catalytic SO2 > '3 burning, or any catalysis for that matter, has anyone *ever* thought about an old dead automobile catalytic converter? Available in all sorts of sizes and even a pretty bad (free) one is bound to have more than enough PGM on it to suffice, after burning off the soot or chipping out melted ceramic to get it operable.

I have one and, after heating the honeycomb up to orange heat with my propane burner, I can shut it off and turn it back on. Hotspots light up and it burns the gas/air mixture flamelessly.

Tim

Very clever...Maybe one could just use the catalist itself, connect the sulphur burner + air intake to one side, yield SO3 on the other side... nice

.
2nd hand catalysts are available very cheap, I've seen them for less then 50€. If thát would work, that would be great! Nice idea, Tim!

neutrino - 25-8-2005 at 05:17

If you try that, make sure to get one of the newer ones that don't use Pt. Sulfur is a known poison to Pt-based catalysts.

Mr. Wizard - 25-8-2005 at 06:52

Quote:

Originally posted by neutrino
If you try that, make sure to get one of the newer ones that don't use Pt. Sulfur is a known poison to Pt-based catalysts.

I thought it was Lead (Pb) that was the well known poison for Pt catalysts? Platinum has been the historical catalyst for SO2->SO3 conversions. Maybe I'm getting old and my memories are getting randomized?

sparkgap - 25-8-2005 at 07:09

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 (~_~)

neutrino - 25-8-2005 at 10:57

Both are poisons.

Taaie-Neuskoek - 25-8-2005 at 11:08

hmm, I found other info, from here

I quote:

Quote:

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.

So here it states that sulphur doesn't kill the catalist, but will just do what we want, convert it!

Mr. Wizard - 25-8-2005 at 14:23

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.

12AX7 - 25-8-2005 at 15:34

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

Fleaker - 25-8-2005 at 16:26

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.

Taaie-Neuskoek - 28-8-2005 at 06:19

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 906 times

I have a suggestion that eliminates the issue of molten sulfur handling, and addresses purification.

Hermes_Trismegistus - 23-9-2005 at 12:38

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...)

Eclectic - 24-9-2005 at 03:07

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?

About the iron sulfide

darkflame89 - 25-9-2005 at 00:11

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

Quote:

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.

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]

oukao - 31-7-2006 at 22:27

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 .