# Dry steam



## InvalidID (Feb 18, 2011)

Can anyone on here tell me if dry steam condenses back to hot water after it's been used or...


----------



## AmericanStand (Jul 29, 2014)

Of course it can be.


----------



## InvalidID (Feb 18, 2011)

Yeah, I found more in my google search about it. Seems pretty practical to use the condensed steam as a heat source.


----------



## AmericanStand (Jul 29, 2014)

What is supplying you with dry steam. ?


----------



## InvalidID (Feb 18, 2011)

Nothing yet, this is still in the research phase. I'm leaning towards a coil system so there isn't a huge tank of dynamite involved. 

The fuel will be biomass, mostly wood chips left over from all the logging and such in the area.


----------



## Darren (May 10, 2002)

InvalidID said:


> Nothing yet, this is still in the research phase. I'm leaning towards a coil system so there isn't a huge tank of dynamite involved.
> 
> The fuel will be biomass, mostly wood chips left over from all the logging and such in the area.


An outdoor boiler is your model. Just produce hot water. That's all you need. If you do steam you're facing more complexity and safety issues.


----------



## InvalidID (Feb 18, 2011)

Darren said:


> An outdoor boiler is your model. Just produce hot water. That's all you need. If you do steam you're facing more complexity and safety issues.


 Without steam I can't run an engine. The model is based around running an engine but capturing the heated water for reuse.


----------



## AmericanStand (Jul 29, 2014)

No need for dry steam. , it’s far more complicated to make and use.


----------



## InvalidID (Feb 18, 2011)

I might be using the phrase wrong, but I was thinking something like this:








Edit to add: Though obviously stationary, I think I could achieve a better recovery rate on the steam.


----------



## AmericanStand (Jul 29, 2014)

What is the purpose of the engine ?


----------



## InvalidID (Feb 18, 2011)

My goal is to produce electricity and use the residual heat as a heat source in winter. It would be pretty nice in a greenhouse, or scaled up a bit to go off grid.


----------



## AmericanStand (Jul 29, 2014)

Humm 
You might want to look into wood gasification. 
The system needs you to draw off as much heat as possible at one stage as opposed to the system you are looking at that works best if you conserve as much heat as possible. 
Plus no dangerous pressures or certified welding needed. 

Check it out at Driveonwood.com


----------



## InvalidID (Feb 18, 2011)

I've looked into wood gas, I think it has it's place but it's not the way I would go. Without a good supply of lubricating oil, filters, and other consumables it's not going to get far enough for my needs. 
In my opinion steams advantages are it's simplicity (You can't beat a turbine for simple) it's relatively low consumables, (No plugs, wires, air filters, oil filters, etc) and it's longevity. A regular genny converted to wood gas is still doing what higher RPM reciprocating engines do, spinning fast and tearing itself apart. 
Meanwhile, you can have a small steam turbine run for thousands of hours before you need to open it up. If you want torque a low RPM piston engine delivers reliability and power on the cheap.

Not to mention the residual heat can be used for heating your home. Woodgas won't do that.


----------



## AmericanStand (Jul 29, 2014)

Well good luck and keep us updated!

In the past I’ve stayed at a lodge both heated and fueled with wood gas. 
After the gas is generated the more heat that is drawn off of it prior to use in a ICE the better. 
That heat can be used to heat a building. 
Is your project for a SHTF situation ?


----------



## InvalidID (Feb 18, 2011)

AmericanStand said:


> Well good luck and keep us updated!
> 
> In the past I’ve stayed at a lodge both heated and fueled with wood gas.
> After the gas is generated the more heat that is drawn off of it prior to use in a ICE the better.
> ...


 It's mostly for the fun of doing it, but I'm cheap and so in order to justify it to myself it's also a potential prep.

If it works fairly well I'm considering using it to heat and power a greenhouse in the meantime.


----------



## doc- (Jun 26, 2015)

FWIW: I've researched wood gas for automotive purposes in the past-- lousy concept if you can use anything else-- hard on the engine & a PITA to keep running properly. Fuel efficiency ~ 1mile per lb of wood chips....I heat with a computer controlled wood gas system. I'm retired, so it's not a problem to be around to mess with it 5x a day.

If your goal is automotive, then turbine or steam locomotive might be the way to go. Remember Andy Granatelli?

If you're trying to use steam to generate electricity in a stationary system, then running your spent steam thru hydronic heating pipes would seem efficient. I don't know enough about steam engines to tell you if that's smart or not-- how much extra fuel will you use if your re-cycled water returns to the boiler for re-heating when it's that much cooler after the diversion thru a heat sink?

Unclear from your post- are you thinking of an automotive application that would double as generator & heater when not on the road? If that were the case, we'd have to wonder if a system small enough to be mobile would be big enough to heat a house?

Re: generating electricity via biomass fuel-- kinda inefficient unless you have demand for a lot of power and it's 24/7. A steam system requires time to build a head on each start up, so you gotta keep it running for max efficiency. (That's what's so dumb about "green" commercial power production- they gotta always keep the coal plants running on idle anyways as back up for the unreliable wind & solar installations.)


----------



## AmericanStand (Jul 29, 2014)

doc- said:


> FWIW: I've researched wood gas for automotive purposes in the past-- lousy concept if you can use anything else-- hard on the engine & a PITA to keep running properly. Fuel efficiency ~ 1mile per lb of wood chips....I heat with a computer controlled wood gas system. I'm retired, so it's not a problem to be around to mess with it 5x a day.
> 
> If your goal is automotive, then turbine or steam locomotive might be the way to go. Remember Andy Granatelli?
> 
> ...


Ok I will bite. 
You say wood gas in a lousy choice if you can use anything else. 
What else do you recommend?
Gas,diesel,kerosene, alcohol are usually the choices people are trying to get away from.


----------



## InvalidID (Feb 18, 2011)

doc- said:


> FWIW: I've researched wood gas for automotive purposes in the past-- lousy concept if you can use anything else-- hard on the engine & a PITA to keep running properly. Fuel efficiency ~ 1mile per lb of wood chips....I heat with a computer controlled wood gas system. I'm retired, so it's not a problem to be around to mess with it 5x a day.
> 
> If your goal is automotive, then turbine or steam locomotive might be the way to go. Remember Andy Granatelli?
> 
> ...


 This is intended as a stationary power and heating application. If it works well it will end up in a greenhouse... When I'm not playing with it of course.

Check out the video I posted earlier. The 'American' steam boiler doesn't require much time to build up a head of steam. That Doble Jay Leno is driving gets warmed up in 2 minutes. The original on demand water heaters!


----------



## wy_white_wolf (Oct 14, 2004)

doc- said:


> ...
> If you're trying to use steam to generate electricity in a stationary system, then running your spent steam thru hydronic heating pipes would seem efficient. I don't know enough about steam engines to tell you if that's smart or not-- how much extra fuel will you use if your re-cycled water returns to the boiler for re-heating when it's that much cooler after the diversion thru a heat sink?...


Not sure about steam engines but steam turbines do benefit from condensing the steam back to water after the turbine. The condensation creates a vacuum to help pull on the turbine instead of just the pressure side pushing. Seems to me it should help a steam engine as it would help in pulling the spent steam out of the engine on the exhaust stroke.

Using a condenser in the greenhouse could extract a lot of heat out in the process and return the water back to the boiler. It only releases 1 calorie of heat when you drop 1 gram of water 1C but to change from vapor o liquid releases 80 calories for 1 gram of water. That would be a big gain in heat.

It also has the added benefit of being pure water so no hard water buildup inside the boiler that would need cleaned out. All of that would have been left behind the first time it went through the boiler.

WWW


----------



## doc- (Jun 26, 2015)

AmericanStand said:


> Ok I will bite.
> You say wood gas in a lousy choice if you can use anything else.
> What else do you recommend?
> Gas,diesel,kerosene, alcohol are usually the choices people are trying to get away from.


Wood gas production is dirty-- a lot of tar builds up in the engine & plumbing shortening life. Wood gas was used extensively in 'Europe during WW II when other, more efficient, preferable fuels were not available. No need to "get away from" those better fuels. It's a matter of availability.

Another big draw back to wood gas for a car is that if you were going to rob a bank, you'd have to leave it running or it would take too long for your getaway. Some one might steal it while you were in the bank.


----------



## doc- (Jun 26, 2015)

wy_white_wolf said:


> Using a condenser in the greenhouse could extract a lot of heat out in the process and return the water back to the boiler. It only releases 1 calorie of heat when you drop 1 gram of water 1C but to change from vapor o liquid releases 80 calories for 1 gram of water. That would be a big gain in heat.
> 
> WWW


But you gotta put that extra 80 cal/gm + losses (2nd Law) back in to turn water back into steam.

Since you're talking about a "non-vital" application and a free fuel source, who cares? It sounds like a good idea.


----------



## AmericanStand (Jul 29, 2014)

doc- said:


> Wood gas production is dirty-- a lot of tar builds up in the engine & plumbing shortening life. Wood gas was used extensively in 'Europe during WW II when other, more efficient, preferable fuels were not available. No need to "get away from" those better fuels. It's a matter of availability.
> 
> Another big draw back to wood gas for a car is that if you were going to rob a bank, you'd have to leave it running or it would take too long for your getaway. Some one might steal it while you were in the bank.


Lol you sound like you are stuck in the 40s ,like everything else wood gas has come a long way since then. 
Most wood gas vehicles would be turn the key and drive away at your bank robbery. 
If fact they are so seemlessly integrated into modern life you probable wouldn’t notice one.


----------



## AmericanStand (Jul 29, 2014)

doc- said:


> But you gotta put that extra 80 cal/gm + losses (2nd Law) back in to turn water back into steam.
> 
> Since you're talking about a "non-vital" application and a free fuel source, who cares? It sounds like a good idea.


 That’s the idea behind dry steam, to avoid that massive energy draw at phase change.
It’s also the reason it’s a bad idea in The OPs application , in dry steam you want to keep as much heat in as possible and never condense


----------



## InvalidID (Feb 18, 2011)

Well, the idea behind dry steam in this case is to avoid the added wear on parts. High speed water vapor is like millions of tiny hammers banging on things.

It seems to me if your steam went through your engine and didn't at least get very close to phase change you've left energy in the system. You're either heating up too much steam or you need a bigger engine at that point. 

Also, from what I've read about the steam turbines on ships they use the hot water for a lot of other things besides driving the ship.


----------



## AmericanStand (Jul 29, 2014)

I see what you are thinking. 
The trick is you keep reusing that superheated steam. 
If your 500 degree steam drops 30 degrees in use you only have to add 30 back to reuse it.


----------



## InvalidID (Feb 18, 2011)

AmericanStand said:


> I see what you are thinking.
> The trick is you keep reusing that superheated steam.
> If your 500 degree steam drops 30 degrees in use you only have to add 30 back to reuse it.


 When I was looking onto how they reused steam back in the early days it seems they reused it as water with a steam injector. I really interesting system, and really rather ingenious. But the idea of trying to reuse the heated steam presented the problem of the tank already being under pressure. 
The most efficient way to reuse the steam was to allow it to cool enough to condense down to water again, then use a small amount of the steam pressure bled off of the system to inject the water back into the boiler. Otherwise you have to spend energy to re-compress the steam. If you can do that without wasting energy you're on track to perpetual motion.


----------



## AmericanStand (Jul 29, 2014)

Don’t get side tracked with wanting to go back to water. 
Just keep using it as steam.


----------



## doc- (Jun 26, 2015)

AmericanStand said:


> Lol you sound like you are stuck in the 40s ,like everything else wood gas has come a long way since then.
> Most wood gas vehicles would be turn the key and drive away at your bank robbery.
> If fact they are so seemlessly integrated into modern life you probable wouldn’t notice one.


You're talking about running pure methane (wood gas). We're talking about generating it on board as you go (methane, H2 & impurities). If you wanted to go that route, then methanol (wood alcohol), used by the Indy cars, is even better.


----------



## wy_white_wolf (Oct 14, 2004)

doc- said:


> But you gotta put that extra 80 cal/gm + losses (2nd Law) back in to turn water back into steam.
> 
> Since you're talking about a "non-vital" application and a free fuel source, who cares? It sounds like a good idea.


Yes. But if it were beneficial to return steam to the boiler the big guys would do it. I don't know of any thermal power plant that returns steam to the boiler.

WWW


----------



## InvalidID (Feb 18, 2011)

wy_white_wolf said:


> Yes. But if it were beneficial to return steam to the boiler the big guys would do it. I don't know of any thermal power plant that returns steam to the boiler.
> 
> WWW


 This is my take as well. The way I understand it, if steam comes out of the other end of your engine you've not used all the energy. It's exactly like running rich in an internal combustion engine. Wasted fuel.


----------



## AmericanStand (Jul 29, 2014)

wy_white_wolf said:


> Yes. But if it were beneficial to return steam to the boiler the big guys would do it. I don't know of any thermal power plant that returns steam to the boiler.
> 
> WWW


 I think you’re technically correct . Steam that has been used is returned through a superheater to be used again as dry steam .


----------



## AmericanStand (Jul 29, 2014)

Do we have any professional steam plant operators here ? I have to admit I am at the very edge of my understanding some of the technicalities we’re dealing with here .

Most of my knowledge and experience with super heated dry steam came Along with pinched fingers, grease and a lot of sweat while rebuilding a steam locomotive. 
That technology would have to be about 75 years old now and may not be the most up-to-date


----------



## wy_white_wolf (Oct 14, 2004)

AmericanStand said:


> Do we have any professional steam plant operators here ? I have to admit I am at the very edge of my understanding some of the technicalities we’re dealing with here .
> 
> Most of my knowledge and experience with super heated dry steam came Along with pinched fingers, grease and a lot of sweat while rebuilding a steam locomotive.
> That technology would have to be about 75 years old now and may not be the most up-to-date


No boiler license but I do work at a thermal power plant as a designer/draftsman. The term dry steam refers to the amount of moisture (water droplets) in the steam at point of saturation. Less than 0.5% is usually considered dry steam. 

Reaching well above this point for Thermal plants is critical. With turbines turning 3600 rpm any condensation of water droplets in there would reek havoc.

WWW


----------



## wy_white_wolf (Oct 14, 2004)

InvalidID said:


> This is my take as well. The way I understand it, if steam comes out of the other end of your engine you've not used all the energy. It's exactly like running rich in an internal combustion engine. Wasted fuel.


Yes, In order to take all the energy out you'd need to condense it back to liquid and return to the starting temperature. But when you consider the different properties of vapor and liquid you see that isn't possible in a turbine. Imagine a 1000F steel turbine blade hitting raindrops at 500mph. It's like a bullet hitting a thin mild steel plate. Turbines it's still dry steam when it exits the last stage and then enters a condenser to create a vacuum to pull on the turbine. 

Some condensation can be dealt with in an engine.

WWW


----------



## AmericanStand (Jul 29, 2014)

So in your plant they heat itt well above boiling then condense it AFTER use, then reboil it ?


----------



## AmericanStand (Jul 29, 2014)

Does it run through a string of turbines each extracting some energy before being condensed ?


----------



## InvalidID (Feb 18, 2011)

wy_white_wolf said:


> Yes, In order to take all the energy out you'd need to condense it back to liquid and return to the starting temperature. But when you consider the different properties of vapor and liquid you see that isn't possible in a turbine. Imagine a 1000F steel turbine blade hitting raindrops at 500mph. It's like a bullet hitting a thin mild steel plate. Turbines it's still dry steam when it exits the last stage and then enters a condenser to create a vacuum to pull on the turbine.
> 
> Some condensation can be dealt with in an engine.
> 
> WWW


 I do know that in steam engines and turbines you want the steam to remain dry until it has left the engine. This is less critical in piston engines than turbines of course.
This is why builders like Doble had multi-cylinder engines, as the steam still has energy left when it leaves the main cylinder and was pumped into another larger cylinder to expand again. I think some of the old marine applications had as many as 3 cylinders, which seems like a lot to manage without computers to assist. 

From what I've read, the ultimate in efficiency is when the steam condenses immediately after leaving the engine. That makes sense to me, though I'd guess it's one of those impractical, perfect world theories. 

I think another difference that AmericanStand may be missing is the on demand nature of modern steam production. On those old locomotives you had a big ol' boiler and a lot of water. Pumping steam back into a boiler would be efficient for that application as it would help increase the temperature of the yet unboiled water.

Modern steam doesn't (and I might be wrong here) sit in a large tank. Water sits in a tank and is forced into coils, the coiled pipes are heated which converts the water very quickly and efficiently. Once the the desired pressure is reached the burners turn off or down, when that pressure is released the burners are turned back up and more water injected. 

I'm doing a piss poor job of explaining this, but the idea is it is beneficial to have the water that's being injected into the heating area as condensed as possible so you can get the largest pressure increase.


----------



## InvalidID (Feb 18, 2011)

AmericanStand said:


> Does it run through a string of turbines each extracting some energy before being condensed ?


 The turbines I've studied, the 'inlet' side is much smaller than the exhaust. In effect, each turbine is a string of turbines all in one tube.


----------



## AmericanStand (Jul 29, 2014)

In old steam locomotives understand it can go both ways either the water can be in the tubes or the heat can flow through the tubes the way I understand it having the water in the tube was more responsive .
But a lot more dangerous. 
To me it always seem like having the water in larger amounts sloshing around in the boiler would be far more dangerous.


----------



## wy_white_wolf (Oct 14, 2004)

InvalidID said:


> ...
> Modern steam doesn't (and I might be wrong here) sit in a large tank. Water sits in a tank and is forced into coils, the coiled pipes are heated which converts the water very quickly and efficiently. Once the the desired pressure is reached the burners turn off or down, when that pressure is released the burners are turned back up and more water injected.
> 
> I'm doing a piss poor job of explaining this, but the idea is it is beneficial to have the water that's being injected into the heating area as condensed as possible so you can get the largest pressure increase.


You didn't do too bad and any corrections I might make would be more to differences in small and large boilers. 

Large systems do still have a tank (called steam drum). Water level is maintained to a set point in the drum. It has tubes out the bottom that form "water walls" surrounding the fire. Coming out of the top of the drum are steam tubes that lead to pendants of tubes that hang into the boiler gas pass (exhaust) and superheat the steam. There are also tubes in the final stages of the exhaust gas to preheat the water going into the drum. For us water temp in the drum is @600F at 1800-2000psi.

Steam leaving the superheaters is @2000F at 1700 to 1900psi. Then it is regulated down to a constant 1000F at 1000psi by water injection for the first stage of the turbine.

WWW


----------



## AmericanStand (Jul 29, 2014)

I’m surprised at how much the temperature and the pressure keeps changing


----------



## wy_white_wolf (Oct 14, 2004)

AmericanStand said:


> I’m surprised at how much the temperature and the pressure keeps changing


Consider it more like compressed air in a shop. Compressor tank will have high pressure and you regulate it down for the jobs (tools) using it.


----------

