Sciencemadness Discussion Board - Steam pressure chamber for 1000C

Steam pressure chamber for 1000C

yobbo II - 12-1-2017 at 10:48

I want to make a chamber to hold water vapour at 1000C (one thousand C) at less than 50 psi.
Having attempted to read up on the subject I reckon I need hastelloy or inconel 625 to make the actual chamber. I am sure that there are other alloys but they seem to be the most common and that is their most common names.
The chamber will sit in a furnace at around 1000C and will be approx. 6 inches long by 2 inches in diameter (a pipe).
Wall thickness about 6mm thick?
One end will probably be welded shut with a black plate and the other end will have an door of sorts.
The door will consist of a blank plate with four nuts and bolts holding it shut with the bolts welded to the pipe.
The end cap and pipe end will have to be ground flat for a seal.
The device will run for hours at a time.
Is there anything I can use for a door seal?

Can anyone advise me on this as I have not a clue as to whether or not this will work.
Hastelloy is not easy to get cheap. I was hopeing to get some end cuts on ebay but they are not to be had though that could change.

eg.
http://www.ebay.com/itm/Galigher-Hastelloy-Sleeve-58253/2709...

Cheers,
Yob

Magpie - 12-1-2017 at 11:07

1000°C is not possible at 50 psi. Saturated steam pressure at 374°C is 3206 psia.

Check the steam tables for saturated steam.

Maroboduus - 12-1-2017 at 11:18

Quote: Originally posted by Magpie

1000°C is not possible at 50 psi. Saturated steam pressure at 374°C is 3206 psia.

Check the steam tables for saturated steam.

1000C steam is possible at any pressure. It's just a matter of having the right amount of water in the chamber. I have no idea why anyone would want to do that (high temp steam at low pressure), but it can obviously be done.

You'd have to evacuate air from the chamber before heating it because the air would make substantial pressure itself . Just the right amount of water in a fairly hard vacuum and when heated you'll get 50PSI at 1000C.

I would ordinarily be quite reluctant to contradict Magpie on matters such as this, however this seems pretty clear-cut.

EDIT: If you just heat water to 1000C in a chamber with a 50PSI blowoff valve you'd get almost the same result since all that vented steam would purge nearly all of the air along with it. Don't know where you could find a blowoff that functions at those temperatures and pressures though.

[Edited on 12-1-2017 by Maroboduus]

EDIT: Any pressure below the threshold for going supercritical, that is.

[Edited on 12-1-2017 by Maroboduus]

[Edited on 12-1-2017 by Maroboduus]

Magpie - 12-1-2017 at 11:32

I have to agree that water can be evaporated to a gas and held at 1000°C, or any higher temperature, for that matter, at 50psi. But it won't be saturated steam and there will be no liquid water in the same location.

edit: For 1000°C I think you are going to have to use a graphite gasket. Or, possibly a screwed cap with lapped mating surfaces for a metal-on-metal pressure fit might work.

[Edited on 12-1-2017 by Magpie]

[Edited on 12-1-2017 by Magpie]

[Edited on 12-1-2017 by Magpie]

unionised - 12-1-2017 at 12:06

Quote: Originally posted by Magpie

I have to agree that water can be evaporated to a gas and held at 1000°C, or any higher temperature, for that matter, at 50psi. But it won't be saturated steam and there will be no liquid water in the same location.

edit: For 1000°C I think you are going to have to use a graphite gasket. Or, possibly a screwed cap with lapped mating surfaces for a metal-on-metal pressure fit might work.

[Edited on 12-1-2017 by Magpie]

[Edited on 12-1-2017 by Magpie]

[Edited on 12-1-2017 by Magpie]

At 1000 C there won't be any liquid water regardless of the pressure.
https://en.wikipedia.org/wiki/Critical_point_(thermodynamics)

Nobody asked about saturated steam, did they?

Magpie - 12-1-2017 at 12:36

No, that was my own misinterpretation.

unionised - 12-1-2017 at 14:13

I have to say the interesting question here is "why?".
Why would anyone want thousand degree steam?

Dr.Bob - 12-1-2017 at 19:34

But if you heat a container to 1000 degrees, it will not contain any real amount of steam, as it would vent out immediately, due to the vapor pressure, and there would not be any real amount of steam left. Temperatures much lower that that are used to dry things, so all water vapor will be driven off well before 1000 degrees, unless the container is sealed, and then it will just explode. Without special pressure equipment, this makes no sense.

Morgan - 13-1-2017 at 07:55

I was reading some ranges for power stations.
"For a Super/Ultra critical steam turbine (3 to 4 Pressures/Sections , as high as 1000 Mw) - HP inlet Pressure/Temp - 235/285 bar and 570/620 Deg C."

Fulmen - 13-1-2017 at 08:39

Quote: Originally posted by Dr.Bob

Without special pressure equipment, this makes no sense.

It''s really quite simple, just add a pressure regulator. It would have to be mounted outside the furnace, but that's not really a big deal.

Expect to do most of the leg work yourself, 1000°C is outside most peoples experience and comfort zone. I would assume that almost any of the nickel-based superalloys would work, you just have to see what you can get hold of.

For calculating the minimum wall thickness, here's a useful page:
http://www.amesweb.info/StressStrainTransformations/StressIn...

wg48 - 13-1-2017 at 10:25

Quote: Originally posted by Fulmen

Quote: Originally posted by Dr.Bob

Without special pressure equipment, this makes no sense.

It''s really quite simple, just add a pressure regulator. It would have to be mounted outside the furnace, but that's not really a big deal.

The regulated would have to be at the same temperature as the pressure vessel to prevent water condensing in it.

On a different point: like Dr Bob I am curious as to what the OP is trying to do.

unionised - 13-1-2017 at 10:39

Quote: Originally posted by wg48

Quote: Originally posted by Fulmen

Quote: Originally posted by Dr.Bob

Without special pressure equipment, this makes no sense.

It''s really quite simple, just add a pressure regulator. It would have to be mounted outside the furnace, but that's not really a big deal.

The regulated would have to be at the same temperature as the pressure vessel to prevent water condensing in it.

On a different point: like Dr Bob I am curious as to what the OP is trying to do.

No, it would have to be hot, but not that hot. As long as it's above the boiling point of water at 50PSI it's not going to be an issue.
There are also other tricks you can use.

Is there anyone who doesn't wonder what the OP's objective is?

wg48 - 13-1-2017 at 11:00

Yes Unionised is correct. I checked about 135C for about 3 bar so not too difficult.

yobbo II - 13-1-2017 at 11:33

Thanks alot for all the replys.

Hope the application does not sound too boring.
I am conveting iron to magnetite as per this thread
http://www.sciencemadness.org/talk/viewthread.php?tid=71009

I thought it might be useful to up the pressure a bit if it is not too difficult, not that I can say it will be any advantage.

See diagram.

"No, it would have to be hot, but not that hot. As long as it's above the boiling point of water at 50PSI it's not going to be an issue.
There are also other tricks you can use."

What other tricks could you use to regulate the pressure?

If I used graphite as a gasket would it not oxidize at 1000C in the presence of water vapour?

Cheers,
Yob

Magpie - 13-1-2017 at 13:21

50 psi is not a very high pressure but 1000C is a quite high temperature. I would use steel, use lapped mating surfaces, forget pressure regulation. Calculate the amount of water needed and assume you reach pressure at temperature.

Don't use a standard flange (too large) but instead use a screwed cap (internal threads). I hope you have a large budget.

Fulmen - 13-1-2017 at 13:45

Quote: Originally posted by wg48

The regulated would have to be at the same temperature as the pressure vessel to prevent water condensing in it.

Not really. So what if there is condensed water in the system? Start with a excess of water, as it evaporates it will bleed off through the regulator.

If you want simple regulation you could try a simple weighted lid (pressure cooker style), but I fear you will have problems maintaining a perfect seal.

Magpie - 13-1-2017 at 14:00

I'm going to reverse myself and say that I like Fulmen's pressure regulator. This would be a good safety device and eliminate the need for hydrostatic testing.

You are building a pressure vessel. The high temperature will derate the normal strength of the metal. This must be taken into account during design.

Will the pressure drop during the reaction to form magnetite? Does this matter?

My household water pressure is 65 psi. Water line connections at the sinks are metal-to-metal compression sealed.

Nuclear grade graphite gasketing good for 1000C is available.

[Edited on 13-1-2017 by Magpie]

Twospoons - 13-1-2017 at 14:45

Personally i would reverse your setup and build the furnace inside the pressure chamber. That way you could use cheap, readily available materials (like steel) for the chamber as it would be at lower temperature- say 200C to prevent condensation.
This also greatly expands the range of materials you can use for the 1000C reaction chamber, as it no longer has to resist any pressure, or be sealed tight.
In my opinion, trying to build a pressure chamber to withstand 50psi at 1000C is quite a challenge.

And ask yourself this: if iron reacts with water at 1000C, what happens to Hastelloy? Or any other metal you might choose?

[Edited on 13-1-2017 by Twospoons]

[Edited on 13-1-2017 by Twospoons]

j_sum1 - 13-1-2017 at 15:06

I am not understanding the why of this project.
Unless you have an enormous volume the actual quantity of steam will be small. Are you sure that you cannot achieve your goal with an HHO torch?

yobbo II - 13-1-2017 at 15:17

Quote: Originally posted by Magpie

50 psi is not a very high pressure but 1000C is a quite high temperature. I would use steel, use lapped mating surfaces, forget pressure regulation. Calculate the amount of water needed and assume you reach pressure at temperature.

Don't use a standard flange (too large) but instead use a screwed cap (internal threads). I hope you have a large budget.

Use ordinary steel?

I will be placing pieces of ordinary steel into the (inert) chamber and they will be converted to magnetite by the action of the hot water vapour. This takes about 12 hours of action at atmospheric pressure (a stream of water vapour going into a simple brick furnace heated with nichrome wire) to convert a piece of steel that is about 3mm thick. Hydrogen produced must be kept sweped away.
I cannot use ordinary steel in my pressurised reaction chamber where the temperature is high as it will simple react with the water vapor and turn into magnetite.
I can use ordinary steel or perhaps more ordinary stainless steels outside the furnace where temperatures are low.
I was hopeing a simple waited or spring loaded valve on the very end of the outlet pipe would suffice as a valve. Simple, cheap and safe.

The graphite seals from the nuclear industry would cost an arm and a leg I would imagine.
There are lots of graphite seals for exhausts available but they will not work in an oxidizing atmosphere at 1000C. Exhausts fumes would be reducing atmospheres.

I would use a screw cap on the reaction chamber/tube if I can get a piece of hastelloy (etc) with threads on it and an end cap but that is unlikely. It would cost too much to have a threaded pipe and end cap (hastelloy made up.
I might get lucky and get something on ebay. Here's an end cap of sorts.

http://www.ebay.com/itm/Dixon-1-Hastelloy-Cam-Lok-Couplers-H...
Its a bt too small (one inch dia).
Now all I need is the threaded pipe!

Magpie - 13-1-2017 at 15:48

I don't see how that coupler would work - it's open on both ends.

Are you going to have to pump in water to maintain pressure and vent H2?

edit: I see from your sketch that that is what your boiler will do.

Please give us the chemical reaction for this process.

[Edited on 14-1-2017 by Magpie]

unionised - 13-1-2017 at 16:01

Quote: Originally posted by yobbo II

Thanks alot for all the replys.

Hope the application does not sound too boring.
I am conveting iron to magnetite as per this thread
http://www.sciencemadness.org/talk/viewthread.php?tid=71009

I thought it might be useful to up the pressure a bit if it is not too difficult, not that I can say it will be any advantage.

See diagram.

"No, it would have to be hot, but not that hot. As long as it's above the boiling point of water at 50PSI it's not going to be an issue.
There are also other tricks you can use."

What other tricks could you use to regulate the pressure?

If I used graphite as a gasket would it not oxidize at 1000C in the presence of water vapour?

Cheers,
Yob

That's interesting to know.
I rather suspect it means that your system won't work- because there's an equilibrium between steam, hydrogen, iron and its oxides.
Get some sort of container, put iron in it, heat it to 1000C, blow steam through it from some sort of steam generator to flush out the hydrogen produced.

Fulmen - 13-1-2017 at 16:21

I see. You will need a continuous stream of water vapor, luckily this shouldn't be hard to achieve. A small boiler running at operating pressure should be simple to make, and as long as you have a continuous gas feed a weighted valve should work fine.

unionised - 14-1-2017 at 03:55

This isn't a complicated process- it's been around for a couple of hundred years and used to be common enough experiment to get described in books as a preparation method for hydrogen.
the "typical" vessel back then was a gun barrel and it was heated to red hot.
Any bit of modern thick walled steel pipe would do the job

https://books.google.co.uk/books?id=vBpkAAAAcAAJ&pg=PA12...

https://books.google.co.uk/books?id=-ucTAAAAQAAJ&pg=RA1-...

xfusion44 - 14-1-2017 at 16:52

1000°C at 50psi is only possible if some of the steam is allowed to vent (constantly). But it'd be hard to regulate that.

[Edited on 15-1-2017 by xfusion44]

Magpie - 14-1-2017 at 18:24

Assuming the following reaction:

3Fe + 4H2O = Fe3O4 + 4H2

Water will have to be continuosly fed from the boiler to replenish that consumed and to flush out the H2.

unionised - 15-1-2017 at 01:02

Hang on,
50PSI is not needed
1000 C is not needed.
What's to discuss?

Fulmen - 15-1-2017 at 05:23

How did you come to that conclusion? Sure the reaction runs at lower pressures and temperatures, but as I understand it he wants to increase reaction speed.

unionised - 15-1-2017 at 05:26

Quote: Originally posted by Fulmen

How did you come to that conclusion? Sure the reaction runs at lower pressures and temperatures, but as I understand it he wants to increase reaction speed.

Which won't happen in a closed container because it will set up an equilibrium.

There are also far simpler ways to make magnetite, but that's a different matter.

Fulmen - 15-1-2017 at 11:01

True. There must be a continuous stream of vapor, but that isn't hard to solve. As for the process, I'm guessing he's after solid magnetite.

unionised - 15-1-2017 at 11:08

Given that it melts around 1600C, solid is the only real option.
There's no reason to think that 50 PSI steam and 1000 C would give particularly big crystals.

yobbo II - 15-1-2017 at 13:31

The reaction chamber is not closed as per the diagram at top.
It is easy (imo) to obtain a stream of water vapour through the set up (diagram) using a simple variable weighted valve on the outlet.
As for 'single crystals' or pieces of magnitite read this short thread (same link is above too!).
http://www.sciencemadness.org/talk/viewthread.php?tid=71009
See the patent attached for more info. (using atmospheric pressure and 1000C). I am converting pieces of iron or steal into (similarly shaped) pieces of magnetite. I am not trying to produce magnetite as a reagent to put into a jar and use somewhere else.

I simply want to increase the pressure of the chamer a bit a bit to see what will happen. As Fulmen suggests it will increase reaction speed.

The seal between chamber and door is what I am wondering about.

Using ordinary steel as a chamber will not work as it cannot be reused and will react itself to form magnetite (I don't want/need crusts of various shapes of magnetite) and hydrogen.

Attachment: US2727842.pdf (435kB)
This file has been downloaded 344 times

Fulmen - 15-1-2017 at 13:55

As long as you're going for the boiler approach the seal shouldn't be a problem. A slight leak should be acceptable, after all you need to vent the hydrogen.

Magpie - 15-1-2017 at 15:30

As you say, ordinary steel and stainless steels aren't going to cut it. A nickel alloy like Hastelloy c276 will likely be best for cost, strength, machinabiliy, corrosion resistance, and weldability.

The pressure control valve won't be much of a problem as it can be located in a much cooler environment. Just use a pressure gage and a needle valve.

[Edited on 15-1-2017 by Magpie]

[Edited on 15-1-2017 by Magpie]

Magpie - 16-1-2017 at 11:31

Here you go

:

http://www.ebay.com/itm/Galigher-Hastelloy-Sleeve-58253-/270...

18 hrs left on this auction.

or,

https://store.advanceops.ca/products/07190n

[Edited on 16-1-2017 by Magpie]

yobbo II - 25-2-2017 at 15:34

Maximum Service Temperatures in dry air

Alloy Temperature
°F °C
Inconel 600 2150 1175
310 2100 1150
Inconel 625 1800 982
Hastelloy C276 800 427
304L 1500 816
321 1500 816
316L 1500 816
AL6XN 1000 538
Monel 400 800 427
Bronze 450 232
Brass 450 232
Copper 400 204
Note: the temperature ratings in the table are general guidelines and could change if corrosives are present, such as sulfur, carbon, etc. In some cases ASME codes will reduce temperature limits too.

Taken from here

http://www.penflex.com/service-temperatures-of-austenitic-st...

It is confusing at to what temperature hastelloy c-276 can be used up to.
The above source says 427C

It would be too much to push it to 1000C.
The inconel 600 will not withstand a highly oxidizing (water vapour) atmosphere at 1000C

macckone - 25-2-2017 at 17:32

This is one of those speed vs quantity problems.
A much larger container is possible at a lower temp and pressure.
A high temp ceramic isn't going to handle much pressure
But your volume is basically as big as you want for a furnace.
As your pressure and temp go up, your working volume
Decreases rapidly due to material strengths dropping at
Elevated temp.

TZM is the only alloy I find with a service temp that high.

yobbo II - 26-2-2017 at 16:00

Perhaps I could make a pipe from some ceramic cement + blanket and put some sort of lapped lid on it with lugs for alloy 600 bolts. Alloy 600 bolts are available not too expensive, they will withstand 1000C so long as the conditions are not too oxidizing (air is ok)

Could make inconel 600 bolts and nuts from rod

macckone - 26-2-2017 at 20:33

Not melting is significantly different from having a
decent yield strength. At 1000C there just isn't much
that will withstand any pressure. Honestly, ceramics
are going to be better at that temperature than most
metals. The TZM listed is the only metal that has a
significant yield strength at that temp.

Now you could do a metal outer shell with a ceramic
insulating shell and a heated inner ceramic shell.
Then the outer shell doesn't have to withstand the
temperature and the ceramic doesn't have to
withstand the pressure.

The ammonia production process uses a similar setup.
There the problem is somewhat different as the
inner shell has to deal with hydrogen embrittlement.
The pressure is higher but the temperature is more
reasonable.

yobbo II - 13-3-2017 at 05:29

Can anyone see why the following would not work?

There is no need for bolts.
Hopeing that the lapped seal(s) at the end(s) would be ok. If small amounts of water vapour leak that is not a big problem.
The pipe and ends would need to be some sort of nickel alloy so it does not corrode. Pressure is low (less that 50 or probably 10 PSI)
I can weld one end plate on as I only need to get access to the pipe from one end.
Standard garage furnace will be ok. No need to make a metal + ceramic 'special' furnace.

TFYT
Yob

[Edited on 13-3-2017 by yobbo II]