Theory question: Pressure/temperature limits
-
- Full Steam Ahead
- Posts: 186
- Joined: Sun Sep 02, 2012 2:39 pm
- Boat Name: No Boat Yet
- Location: Cathlamet, WA
Re: Theory question: Pressure/temperature limits
The Mechanic's Magazine, Museum, Register, Journal and Gazette
Volume 29
1838
Page 360 " The Victoria Explosion Inquest" talks of the reaction of red hot iron absorbing oxygen and liberating hydrogen as part of the reaction. In my youth I read of early steamboat boiler explosions often being accompanied with a blue flash. This was attributed to the liberated hydrogen igniting when it came in contact with the fire after the crown sheet failed. I used to be able to crank out the stoichiometry in my head, and am now to lazy to get the book of the shelf, in other words, Technicality quickly overcomes curiosity.
Dave
Volume 29
1838
Page 360 " The Victoria Explosion Inquest" talks of the reaction of red hot iron absorbing oxygen and liberating hydrogen as part of the reaction. In my youth I read of early steamboat boiler explosions often being accompanied with a blue flash. This was attributed to the liberated hydrogen igniting when it came in contact with the fire after the crown sheet failed. I used to be able to crank out the stoichiometry in my head, and am now to lazy to get the book of the shelf, in other words, Technicality quickly overcomes curiosity.
Dave
-
- Full Steam Ahead
- Posts: 134
- Joined: Mon Oct 31, 2016 5:57 pm
- Boat Name: No Boat Yet
- Location: Yukon, OK
Re: Theory question: Pressure/temperature limits
An antiquated way of producing hydrogen was to pass steam over a red hot iron surface, forming hydrogen and magnetite. I suppose that could have been what occurred in such an instance? Probably from an underfilled boiler, although I can't imagine a red hot boiler tube would be able to hold back the pressure.
-
- Full Steam Ahead
- Posts: 186
- Joined: Sun Sep 02, 2012 2:39 pm
- Boat Name: No Boat Yet
- Location: Cathlamet, WA
Re: Theory question: Pressure/temperature limits
Okay I couldn't resist,
3Fe + 4H2O --> Fe3O4(Magnetite) + 4H2
The Iron must be red hot and the water in the form of steam.
Dave
3Fe + 4H2O --> Fe3O4(Magnetite) + 4H2
The Iron must be red hot and the water in the form of steam.
Dave
- fredrosse
- Full Steam Ahead
- Posts: 1906
- Joined: Fri Nov 20, 2009 5:34 am
- Boat Name: Margaret S.
- Location: Phila PA USA
- Contact:
Re: Theory question: Pressure/temperature limits
As far as "bash valve" engines are concerned, I have always thought of them as very primitive and unworthy of consideration. However the White Cliffs Solar project used a 3 cylinder uniflow engine with bash valves, and this engine ran reliably for years, producing up to about 25 kW. The bash pins hit the ball bearing type steam admission valves for only a vety short duration, so the low piston velocity when the pins hit the balls was acceptably slow to allow long life. This engine ran with 600 psi steam, about 40 Barg.
http://www.rossen.ch/solar/wcengine.html
This engine is very efficient, the best of reciprocating steam engines I have seen in the last 100years, except for the Skinner compound uniflow engines used to power several US Aircraft Carriers during WWII, but they were engines with thousands of horsepower, a whole different realm.
http://www.rossen.ch/solar/wcengine.html
This engine is very efficient, the best of reciprocating steam engines I have seen in the last 100years, except for the Skinner compound uniflow engines used to power several US Aircraft Carriers during WWII, but they were engines with thousands of horsepower, a whole different realm.
- Attachments
-
- wcfig44b.jpg (140.02 KiB) Viewed 4639 times
- barts
- Full Steam Ahead
- Posts: 1069
- Joined: Wed Nov 18, 2009 6:08 am
- Boat Name: Otter, Rainbow
- Location: Lopez Island, WA and sometimes Menlo Park, CA
- Contact:
Re: Theory question: Pressure/temperature limits
Reading the complete report is quite interesting; the detailed descriptions of various problems encountered both in initial development and in maintenance are particularly useful.
One mechanism they describe for oil removal from condensate is the use of stainless steel disks slowly rotating at 10 rpm in the feedwater tank, with some means to wipe the oil off the disks and return it to the oil tank. Those familiar with the problem of tramp oil collection in water-based machine coolants will recognize this mechanism. I don't see any discussion of the type of oil used in the engine; my experiences with oil/water mixtures in Otter's old refrigeration compressor based engine suggest that some non-detergent, non-compounded oil would be best.
Thanks for posting the link!
- Bart
One mechanism they describe for oil removal from condensate is the use of stainless steel disks slowly rotating at 10 rpm in the feedwater tank, with some means to wipe the oil off the disks and return it to the oil tank. Those familiar with the problem of tramp oil collection in water-based machine coolants will recognize this mechanism. I don't see any discussion of the type of oil used in the engine; my experiences with oil/water mixtures in Otter's old refrigeration compressor based engine suggest that some non-detergent, non-compounded oil would be best.
Thanks for posting the link!
- Bart
-------
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
-
- Full Steam Ahead
- Posts: 150
- Joined: Mon Oct 26, 2015 2:32 pm
- Boat Name: No Boat Yet
Re: Theory question: Pressure/temperature limits
Yes, for the boiler tubes to have burned, they must have gotten meltingly hot so to speak. I've burned steel like that in my forge when I began forging, but the metal must already be glowing almost white. That shouldn't be possible in a boiler, even if the tubes are empty. But if they reached red hot heat and steam disintegrated to produce hydrogen, which finds an oxygen source, it's possible.
When I first got interested into steam engines, bash valves or ball valves (what are they officially called?) had a certain attraction to me due to their simplicity. But governing the engine would be only possible by throttling and the concept of 2 pieces of metal hitting against each other at high speeds made me lose interest in them fast. But I can understand why they will always have a fan base. And it's a cheap way for "backyard" IC-engine conversions.
When I first got interested into steam engines, bash valves or ball valves (what are they officially called?) had a certain attraction to me due to their simplicity. But governing the engine would be only possible by throttling and the concept of 2 pieces of metal hitting against each other at high speeds made me lose interest in them fast. But I can understand why they will always have a fan base. And it's a cheap way for "backyard" IC-engine conversions.
the arduino version steam engine indicator: https://app.box.com/s/b2i0z3gw6ny3rcfdet5xjg8ubrfu799i - app version coming soon
Excuse my occasional long response time. It's caused by the side effects from ptsd.
Excuse my occasional long response time. It's caused by the side effects from ptsd.
- barts
- Full Steam Ahead
- Posts: 1069
- Joined: Wed Nov 18, 2009 6:08 am
- Boat Name: Otter, Rainbow
- Location: Lopez Island, WA and sometimes Menlo Park, CA
- Contact:
Re: Theory question: Pressure/temperature limits
Steam will react with red hot iron. If carbon is also present (typical in boilers) other reactions may well occur. See page 12 ofSteam Captain wrote: ↑Sat Feb 13, 2021 2:02 pmYes, for the boiler tubes to have burned, they must have gotten meltingly hot so to speak. I've burned steel like that in my forge when I began forging, but the metal must already be glowing almost white. That shouldn't be possible in a boiler, even if the tubes are empty. But if they reached red hot heat and steam disintegrated to produce hydrogen, which finds an oxygen source, it's possible.
http://www.dieselduck.info/machine/06%2 ... 20EGBs.pdf
That article describes soot fires in exhaust gas boilers on large diesel ships, and resulting 'iron fires'.
- Bart
-------
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
-
- Full Steam Ahead
- Posts: 150
- Joined: Mon Oct 26, 2015 2:32 pm
- Boat Name: No Boat Yet
Re: Theory question: Pressure/temperature limits
I am still amazed by the occurrence. There was a massive metal fire on a scrap yard in the port of a city I lived in in the past and half the city was carpeted with "poker room thick" smoke. It was advised to shut the windows and not to run around outside. (If you ever got welding fever, you know metal fumes can be special). Of course it creeped inside anyways. It wasn't even possible to see down the streets and the smell AND taste was very distinguishable.
On a very different note and more important for us practical users: How much would you estimate the danger of metal fires in plants of our scale? The only small boilers I could figure would be able to end up like this would be those totally heat-laden tiny hydroplane flash steam plants, but I've never seen,heard or read about a launch-sized boiler being fired this extremely. So, I hope this is usually one of these issues which don't scale linearily so to speak.
On a very different note and more important for us practical users: How much would you estimate the danger of metal fires in plants of our scale? The only small boilers I could figure would be able to end up like this would be those totally heat-laden tiny hydroplane flash steam plants, but I've never seen,heard or read about a launch-sized boiler being fired this extremely. So, I hope this is usually one of these issues which don't scale linearily so to speak.
the arduino version steam engine indicator: https://app.box.com/s/b2i0z3gw6ny3rcfdet5xjg8ubrfu799i - app version coming soon
Excuse my occasional long response time. It's caused by the side effects from ptsd.
Excuse my occasional long response time. It's caused by the side effects from ptsd.
- DetroiTug
- Full Steam Ahead
- Posts: 1863
- Joined: Fri Nov 27, 2009 5:56 pm
- Boat Name: Iron Chief
- Location: Northwest Detroit
Re: Theory question: Pressure/temperature limits
Quote ''(If you ever got welding fever, ''
Chromium poisoning, I've had it several times welding ''Cromoly'' tubing. Fever and shakes. Hits ya about five hours afterwards.
Ron
Chromium poisoning, I've had it several times welding ''Cromoly'' tubing. Fever and shakes. Hits ya about five hours afterwards.
Ron
- barts
- Full Steam Ahead
- Posts: 1069
- Joined: Wed Nov 18, 2009 6:08 am
- Boat Name: Otter, Rainbow
- Location: Lopez Island, WA and sometimes Menlo Park, CA
- Contact:
Re: Theory question: Pressure/temperature limits
There's basically no chance for a metal fire to occur w/o a superheater and real mistreatment in our small plants. Keep in mind that modern full scale power plants have a very different distribution of heating surface than our small boilers, with much more heating surface in both economizers and superheaters. Superheaters, particularly radiant ones, are very subject to overheating with reduced steam demand. Locomotive superheaters are all convective as far as I know, placed in larger flue tubes; this would be critical since steam demand can drop suddenly with the fire still going full blast.Steam Captain wrote: ↑Tue Feb 16, 2021 12:30 pmI am still amazed by the occurrence. There was a massive metal fire on a scrap yard in the port of a city I lived in in the past and half the city was carpeted with "poker room thick" smoke. It was advised to shut the windows and not to run around outside. (If you ever got welding fever, you know metal fumes can be special). Of course it creeped inside anyways. It wasn't even possible to see down the streets and the smell AND taste was very distinguishable.
On a very different note and more important for us practical users: How much would you estimate the danger of metal fires in plants of our scale? The only small boilers I could figure would be able to end up like this would be those totally heat-laden tiny hydroplane flash steam plants, but I've never seen,heard or read about a launch-sized boiler being fired this extremely. So, I hope this is usually one of these issues which don't scale linearily so to speak.
- Bart
-------
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
Bart Smaalders http://smaalders.net/barts Lopez Island, WA