Smack /BoyntonStu Debate

[BoyntonStu]

In watercar@yahoogroups.com, "oneandonlysmack" <oneandonlysmack@...> wrote:
>
> Google the definition of a mole. This will explain to you fully what is meant. You can compare molecular weights as they are based on a specific number of molecules/atoms - 6.022 x 10exp(23) regardless of the phase of the substance. I did not use molar calcs.
>
> You can do the proper phase conversions. Liquid to liquid, or gas to gas at STP. You cant compare equal volumes of gas to liquid, liquid to solid, or gas to solid. You must compare equal volumes in their comparable phases. If you go back and perform the calculation correctly, you will find your results are vastly different.
>
> Smack
>

I disagree.

It is really quite elementary.

87 Octane Gasoline 32.0 MJ/Kg

Hydrogen 121MJ/Kg

An energy per weight comparison.

If you vaporize 1 Kg of gasoline you get 32 MJ of energy.

If you liquefy 1 Kg of Hydrogen you get 121 MJ of energy.

32/121 = .26

.26 x 1Kg = .26 Kg

According to the above calculation Hydrogen by weight has almost 4 times the energy of gasoline.

Therefore only .26 Kg of Hydrogen, liquid or gas is required to replace 1 Kg of gasoline.

You can forget Avogadro's Number, moles, and phase change.

Weight and the energy per Kg is the only criteria for comparison of Hydrogen and gasoline.

Another fuel example is firewood:

The energy content of a measure of wood depends on its species[4]. For example, it can range from 15.5 to 32 million BTUs per cord.
The higher the moisture content, the more BTUs that must be used to evaporate(boil) the water in the wood before it will`burn. Dry wood delivers more BTUs for heating than green wood of the same species.

In this wood example, weight is not even mentioned; it is assumed.

You can accurately compare fuel energy of a solid to a liquid or to a gas. It does not matter.

How many Liters of HHO must you generate in order to get .26 Kg of Hydrogen?

Energy/weight is the bottom line.

BoyntonStu

P.S. In order to liquefy Hydrogen, energy is consumed for compression and IMHO it should be factored into the energy calculation.

[Philldpapill]

What do you mean by "vaprozing" gasoline and Hydrogen? Are you literally talking about "heat of vaporization"? If so, that REQUIRES energy. You have to ADD heat(energy) to the gasoline in order to make it change phase. Now, if you are talking about combusting gasoline and Hydrogen, then that's another story.

[BoyntonStu]

What do you mean by "vaprozing" gasoline and Hydrogen? Are you literally talking about "heat of vaporization"? If so, that REQUIRES energy. You have to ADD heat(energy) to the gasoline in order to make it change phase. Now, if you are talking about combusting gasoline and Hydrogen, then that's another story.

That is a point.

We are 'combusting' the fuels.

I believe that the "heat of vaporization" of gasoline can be ignored for several reasons.

You have to supply a lot of heat to vaporize water in comparison to gasoline.

Spill a cup of each onto concrete and measure the time it takes for each to evaporate.

In addition, sucking the 14.7:1 air:gasoline into a heated vacuum cylinder helps in vaporizing the fuel injected spray.

The gasoline cools the engine.

IOW Not much extra needed energy to consider.


You don't consider the "heat of vaporization" when burning wood.

Comparing energy densities is what this discussion is about.

All other factors are minimum.

BoyntonStu

[mytoyotasucks]

Way too much info - now i forgot my first girlfriends name :eek:

[HHO BLASTER]

Way too much info - now i forgot my first girlfriends name :eek:

It was i needitnow

[Philldpapill]

Stu, you are right - the HV is minimal in all this, but I'm just curious WHAT energy those numbers are in reference to. Is this the energy released upon oxidation(probably)? It's just not clear about what you mean when you say:

"If you vaporize 1 Kg of gasoline you get 32 MJ of energy.

If you liquefy 1 Kg of Hydrogen you get 121 MJ of energy."

When you turn a gas into a liquid, you don't "get" energy out of it. It TAKES energy to extract the heat, which then turns it into a liquid. Otherwise, you could just take liquid hydrogen and let the environment heat it up to a vapor, then "get" energy out when you condense it again. I mean, don't get me wrong, that would be a very "cool" thing to do, but that's like having a reverse heat pump that creates a higher temperature differential AND generates power. Like having your air conditioner cool your house, and then sell the energy you got out back to the electric company.

[BoyntonStu]

Stu, you are right - the HV is minimal in all this, but I'm just curious WHAT energy those numbers are in reference to. Is this the energy released upon oxidation(probably)? It's just not clear about what you mean when you say:

"If you vaporize 1 Kg of gasoline you get 32 MJ of energy.

If you liquefy 1 Kg of Hydrogen you get 121 MJ of energy."

When you turn a gas into a liquid, you don't "get" energy out of it. It TAKES energy to extract the heat, which then turns it into a liquid. Otherwise, you could just take liquid hydrogen and let the environment heat it up to a vapor, then "get" energy out when you condense it again. I mean, don't get me wrong, that would be a very "cool" thing to do, but that's like having a reverse heat pump that creates a higher temperature differential AND generates power. Like having your air conditioner cool your house, and then sell the energy you got out back to the electric company.


Sorry, I did not make my point clear.

"If you vaporize 1 Kg of gasoline you get 32 MJ of energy.

Should have been:

"After you vaporize 1 Kg of gasoline in your car, you will get the same 32 MJ of energy that you would have gotten out of the liquid".

and:


Afteryou liquefy 1 Kg of Hydrogen (121 MJ) in your car, you STILL get the same 121 MJ of energy when you burn it in your car.l"


Consider a BBQ tank of liquid propane.

You purchase the liquid by the pound; they weigh it out.

Yhou have purchased energy store as a liquid.

When you burn it, as in all flame combustion, you burn the vapor.

Same for a wax candle, you burn the vapor.

(Solids must be heated to a gas before they burn.


Ever blow out a candle and relight it again when you hold the match an inch above the wick?


It is the gas that ignites, not the wax.


BoyntonStu