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"Closed" Cycle Internal Reaction Engines
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Bret Cahill
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Joined: 05 May 2005
Posts: 480

PostPosted: Tue Jul 18, 2006 6:29 am    Post subject: "Closed" Cycle Internal Reaction Engines Reply with quote

Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.

Eliminate the large heat transfer surface areas of vapor power cycles.


Bret Cahill
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eromlignod
science forum addict


Joined: 02 May 2005
Posts: 68

PostPosted: Tue Jul 18, 2006 1:57 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Bret Cahill wrote:
Quote:
Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.


Like, um, gasoline and air?

Don
Kansas City
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Paul O
science forum beginner


Joined: 01 Feb 2006
Posts: 11

PostPosted: Tue Jul 18, 2006 3:58 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

eromlignod wrote:
Quote:
Bret Cahill wrote:
Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.


Like, um, gasoline and air?

Don
Kansas City


Gasoline! Do you have any idea how flammable that stuff is? How will you
transport it? How will you store it?

Gasoline is waaay to dangerous for use in internal combustion engines.
;-)



Good Luck,
Paul D Oosterhout
(from SAIC)
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Wed Jul 19, 2006 5:58 am    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Quote:
Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.

Like, um, gasoline and air?

The kinematics would be different, not the reversibility.


Bret Cahill
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Wed Jul 19, 2006 12:28 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Quote:
Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.

Like, um, gasoline and air?

Gasoline! Do you have any idea how flammable that stuff is? How will you
transport it? How will you store it?

Gasoline is waaay to dangerous for use in internal combustion engines.

Hollywood likes to have a lot of exploding cars but in real life I've
only seen many accidents that resulted in burning cars in one place:
SE Texas.

My only theories on the issue all hinged on the proximity of the petro
chemical industry. They had gotten into such a habit of sabatoging
refineries for "upsets" they even did it to the fuel lines on their own
motor vehicles.


Bret Cahill
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Wed Jul 19, 2006 10:14 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

You'll often hear about a chemical plant generating electricity from
burning, say, sulphur to heat a boiler as well as to make the product,
H2SO4.

They often also expand a product gas through a turbine to recoup some
of the power used to compress it in the first place, but I haven't
heard too much about "internal" chemical reaction engines.


Bret Cahill
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Don A. Gilmore
science forum beginner


Joined: 24 Mar 2005
Posts: 48

PostPosted: Wed Jul 19, 2006 10:27 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

"Bret Cahill" <BretCahill@aol.com> wrote in message
news:1153347265.590977.252990@h48g2000cwc.googlegroups.com...
Quote:
You'll often hear about a chemical plant generating electricity from
burning, say, sulphur to heat a boiler as well as to make the product,
H2SO4.

They often also expand a product gas through a turbine to recoup some
of the power used to compress it in the first place, but I haven't
heard too much about "internal" chemical reaction engines.


Just what do you think combustion *is* exactly?

Don
Kansas City
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Thu Jul 20, 2006 4:53 am    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Quote:
Just what do you think combustion *is* exactly?

With gasoline it's an irreversible reaction.

What's fast, highly exothermic, reversible, nontoxic and the products
and reactants liquify at 200 psi, 150 F?


Bret Cahill
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lucasea@sbcglobal.net
science forum beginner


Joined: 30 Jun 2006
Posts: 8

PostPosted: Thu Jul 20, 2006 2:54 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

"Bret Cahill" <BretCahill@aol.com> wrote in message
news:1153371230.043050.220400@m79g2000cwm.googlegroups.com...
Quote:
Just what do you think combustion *is* exactly?

With gasoline it's an irreversible reaction.

What's fast, highly exothermic, reversible, nontoxic and the products
and reactants liquify at 200 psi, 150 F?


Remember the universal statement of thermodynamics: deltaG = deltaH -
TdeltaS. If you're going to make a highly exothermic reaction reversible,
the reverse reaction had better have a huge positive entropy, and you need
to run the reaction at very high temperatures, in order to get a deltaG
anywhere near a practical definition of reversibility (as close to 0 as
possible). In practical terms, this means the reverse reaction needs to
involved lots of fragmentation--a very few molecules of condensed material
being converted to a very large number of molecules of gas. Take the
polymerization of ethylene for example (it's one reaction that I know the
thermodynamics of well). It's very modestly exothermic (ca. 25 kcal/mol),
and the depolymerization meets the criterion I described above. However, it
takes very high temperatures to depolymerize PE. Fundamentally, since
you're expecting an exothermic forward reaction, you're going to have to be
making some very strong bonds. Reversing the formation of those bonds is
kinetically also going to require either extremely high temperatures or a
very reactive catalyst--and you better hope that something else in the
molecule doesn't decide to react before those very strong bonds.

Eric Lucas
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eromlignod
science forum addict


Joined: 02 May 2005
Posts: 68

PostPosted: Thu Jul 20, 2006 7:21 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Bret Cahill wrote:
Quote:
Just what do you think combustion *is* exactly?

With gasoline it's an irreversible reaction.

What's fast, highly exothermic, reversible, nontoxic and the products
and reactants liquify at 200 psi, 150 F?


I guess you're trying to cause a reaction without need for ignition?

Furfuryl alcohol will react hypergolically with a nitric acid oxidizer.
It's made by reducing furfural (from distilling corn cobs, sawdust,
etc.) I think they used to use it in rockets. Have fun.

Don
Kansas City
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ghostwriter
science forum beginner


Joined: 07 Jun 2005
Posts: 19

PostPosted: Thu Jul 20, 2006 7:51 pm    Post subject: Re: "Closed" Cycle Internal Reaction Engines Reply with quote

Bret Cahill wrote:
Quote:
Instead of using an equilibrium reaction like 3H2 + N2 <=> 2 NH3 to
heat a boiler maybe there are fast reacting chemicals you could feed to
the intake of what would otherwise be an internal combustion engine.

Eliminate the large heat transfer surface areas of vapor power cycles.


Bret Cahill

Well H2 +1/2O2 = H2O leaps to mind. But the temp need to thermally
split H2O is well above solar thermal. And transport of H2 gas in
pipelines is not really feasible.

Ghostwriter
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