Steam Engines... and Coal... TODAY - I Predict...

Hello everyone... it has been too long since I've perused these halls!

I am on an new adventure... I am looking to purchase a 8 - 12 hp small steam engine to drive a generator to supply my electricity needs 24/7 as well as send any unused power to the grid.

Anyone doing this?

I heat 24/7 with a 1954 AA-130... thanks to Matthaus (still here bro?) and I'm looking to create a non-invasive coil of some type in the fire box to create the steam and then pipe it to an engine... complete with regulators, etc. I am in the beginning stages of learning what can be done and what I'll need to do.

There are steam engines for sale from time to time on ebay - usually built for marine purposes, but there are some available from India as well. The older engines are nice as well, but I'm not a machinist nor do I know one (yet) to buy an older engine. These steam engines from India are not made to look pretty like the marine engines, they are made to work - they are 50% bigger, but may be what I'm looking for.

I have family that have bought into the solar cell 'run' - they are happy with the results so far, but I am not willing to risk that much money for something that may or may not pay back.

Because I heat with good 'ole anthracite, this may be a viable option... anybody doing this??

I am more of an idea person - always have about 6 or so floating around in my brain - but I'm not an engineer... I do understand mathematics and I've been touching up on my physics...

I think this may be a cool/fun/not much risk adventure. Steam can be dangerous and should be respected. Is my optimism unrealistic?

Any thoughts?

Pret

Renewed your hi pressure steam operator's license yet?

Sting wrote:Renewed your hi pressure steam operator's license yet?

That would be the easiest part of this adventure. To start with, your Axeman's output is less than 1/2 HP, it gets worse from there.

pret wrote:I am on an new adventure... I am looking to purchase a 8 - 12 hp small steam engine to drive a generator to supply my electricity needs 24/7 as well as send any unused power to the grid.

Anyone doing this?

The best thing you could do now would be to buy a college Freshman level Physics text book. Use you math skills to understand the examples and work the sample problems. After you have finished the equivalent of a two semester course you will understand why what you are wanting to do can't be done. At least in a residential setting at any practical cost.

A good place to find used text books a cheap prices is at a Goodwill or Salvation Army store. My local Goodwill charges $2.62 for any hardback book.

Here you go, a good used steam engine

http://www.enginads.com/classifieds/showproduct.p ... 5654/cat/7

By the way, this engine requires 150 psi steam (366 deg. F. saturated temp). Sorry, an Axeman-anderson won't work. You might use the AA to preheat the makeup water required.

A simple steam engine will require about 45 lb/hr per hp of steam. That would be 360 lbs an hour for 8 hp. 150 psi steam would require about 1197 btu/lb to produce. At 75% combustion efficiency, this would only be a 576,000 BTU input high pressure asme boiler. Finding a coal boiler this small would be hard. Hurst makes small coal fired high pressure boiler starting at 2,000,000 btu's. You could run more than one steam engine with that.

See this web page:

http://www.hurstboiler.com/boilers/solid_fuel_fir ... ser_hpd_uf

I imagine they could set you up for around $100,000.00.

Sorry for the tounge in cheek reply. Please don't be offended. I applaud your interest, but you will need to learn alot about steam and thermodynamics before understanding why this won't work. The old open cycle piston steam engines were as little as 4% efficient from the coal fire BTU content to the work content. Even todays modern extreme high pressure steam powered turbine generators have a maximum thermodyamic efficiency in the 34% range.

Very interesting replies, educational. Might I ask how a Stanley Steamer worked? This sounds like something that has been discussed before.

Kevin

I have never studied the steamer cars. They used a small flash boiler usually powered by Kero. Here is a diagram I found on the internet. The condenser was a latter added feature to decrease water stops.

Before you get to involved with this project, I would recommend that you contact your state's boiler authority. In CT, that would be the State Police. I find it highly improbable that they will grant you a certificate to operate a high pressure boiler in a residential environment. You may get lucky, but I doubt it. If you can get a certificate, the next thing you will need is an insurer. I would recommend Factory Mutual, you won't have a lot of choices in this department. They will have a lot of hurdles for you to jump before you can fire anything up.

I appreciate everyone's caution, comments, and direction. Steam is dangerous with and without respect. I have and will spend more time learning thermodynamic principals and modern steam manipulation technologies among other topics related to this post.

There are no laws for working with steam in the residential sector for Pa that I have found. Many cities require folks to be certified in working with high pressure steam if their occupation involves steam producing boilers. If I am incorrect, please direct me to that information.

Thank you Yanche for your kind rebuke. I hold you in the highest regard on more than one front.

I am not willing to throw in the towel yet gentleman. I am bringing this here because of the respect I have for many of you. I have been burning coal now for nearly three years successfully due to what I have learned from this forum. If this is not feasible, show me the figures and the calculations. For instance, I am told of a steam engine that will, and I quote, "At 1500 rpm the **** requires 50 cubic feet of steam per minute under 125 psi and produces just over 25 hp" This same engine I am told (not a believer yet) will produce 500 rpm at just under 50 psi"... and will turn a 5kw generator nicely with full load.

I have my doubts and I'm attempting to learn enough to verify the claims (or chuck them). I also need to learn enough to know what is required to produce the aforementioned volume of steam per minute... that I am also determining.

Again, I appreciate your time and thoughts. Help me understand anything I may be missing.

I'm not simply looking for something that is less expensive today... I'm looking into means that may be less expensive 'tomorrow'... and means that I have some control over.

Thanks for your time... Pret

steamup wrote: That would be 360 lbs an hour for 8 hp.

I've always liked the idea of a steam powered something. I work well with steel & have build my own 5500 watt windmill on a 60 foot tower. I often dreamed about steam & after I discovered coal & installed an Axeman Anderson I thought even more about it. Then one day here on the Forum someone asked about steam & I can't quite remember who...Yanche perhaps? maybe, said <not quite a quote> "At some point you will have a long conversation with a very specialized insurance man". I made one phone call. He was right. To insure a steam boiler in a residential setting....forget it!

And then:

Anyone, correct me if I'm wrong in my math:

An 8HP gas generator makes about 4,500 watts. (per hour) So, buying it from the electric company it would 4.4 KW per hour at $.12 a KWH would be $.54 cents an hour. At $.18, seventy nine cents.

360 pounds of coal an hour a ton would last 5.5 hours. 5.5 times $.79 is $4.71. Can you buy coal for less than $5 a ton?

Another issue that needs to be considered is what will be done with the exhaust from the turbine. I do not know much about steam recip engines but with a steam turbine their are two different types: condensing and back pressure turbines. With a condensing, the exhaust steam from the turbine is pulled and then condensed back to water. The water is then reboiled and turned into steam to go back to the steam turbine again. This is know as the Rankine cycle. The condenser water needs to be cooled and pumped that would add big bucks to your electric bill. Here is a picture of one from my job.

The other back pressure turbines do not condense the outlet steam. The outlet steam is used for process steam or for heating. Eventually the steam does end up condensed and back in the boiler. They call them back pressure turbines because the turbines have higher back pressure since they do not have a condenser pulling the steam and creating vacuum. The more back pressure you have and less vacuum, the more inefficient the turbine is going to be. As member Steamup said, these steam turbines are not that efficient to begin with. In fact they are so inefficient that throughout the summer, the majority of the time my plant chooses to run electric chillers over steam powered chillers. Most of the time it is cheaper to import electric than to make steam for the chillers. In your case even if you did engineer a system it might still be cheaper for you to just import electric. If you really are serious about generating electric your best bet would be the solar panels or a windmill. Although they are expensive they will be allot cheaper than building a mini power plant. They will be less maintenance and the electric made by them will be free. But.... If you do find a way to pull this off I am all ears. I have had this idea before and came to the conclusion pretty fast that it was not feasible.
-Luke

Great schematic, I would need to learn alot to understand it all. However, I am at a loss to explain how steam powered cars achieved such speed without HP and how trains pulled with such power without HP.(or ships) I would think the restricted space in a car and the limited temp of kero would have prevented them from producing enough HP to even move. I have seen steam cars in action and they are way cool.

Kevin

No need to go into lengthy explanations with watts/btu's/etc. Just how do you go fast(in a big heavy car) with a kero burner but cant power a generator?

KLook wrote:Great schematic, I would need to learn alot to understand it all. However, I am at a loss to explain how steam powered cars achieved such speed without HP and how trains pulled with such power without HP.(or ships) I would think the restricted space in a car and the limited temp of kero would have prevented them from producing enough HP to even move. I have seen steam cars in action and they are way cool.

Kevin

No need to go into lengthy explanations with watts/btu's/etc. Just how do you go fast(in a big heavy car) with a kero burner but cant power a generator?

gearing. its all in the transmission and final drive..... also energy is stored in a flywheel and extracted slowly as demand increases...

Yes it is cheaper to buy electricity than to try to generate it youself from coal.

Understand reciprocating engines are inefficient at converting BTU from steam to work but stil can generate great hp. A guy Corliss many years ago designed a more efficecient steam engine but they were more complex and costly. He sold his engines through promises in coal savings.

Steam turbines are a differenent concept than the reciprocating engine. The Rankin cycle is the thermodynamic cycle of using a boiler and steam turbine to do work. The efficiency of a Rankin cycle is determined by the diffenence in temperature of the steam between the top and bottom of the cycle. The heat to condense the steam to water is lost heat (and efficiency). This is why power plant have huge cooling towers. This is also why many power plants run in supercritical steam pressures of 1500 psi and above to gain efficiency.

In order to generate electricity from steam efficiently, you need to be a big guy with big equipment and lots of money.

This is not the first time the dream of a coal to electric has been discussed on this forum. As I and others have suggested the steam engine is impractical. I suggest another approach. Use coal gas. While I don't know how about producing it in a residential setting, a century ago it was a widely used industrial process. See: https://en.wikipedia.org/wiki/Town_gas

The goal would be to use a modified internal combustion engine to drive a conventional generator. Perhaps coal is not the ideal fuel and biomass is more suitable. I'd sure like to see the chemistry and physics of what's needed. That's where I would spend my research time.

Edit: Check this link on Gas Engines and Producer Gas Plants:

http://www.old-engine.com/gasbook.htm