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Is it possible to synthesize gasoline from CO2 + H2 + energy? If so then why are we talking about hydrogen, if not why not?
It seems to me you should be able to break apart the CO2 (take it from the atmosphere, makes it carbon neutral) then with H2 (from water) you should be able to build any hydrocarbon you want. What am I missing?
Posts: 62 | From: Raymond, NH | Registered: May 2005
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You're missing the law of conservation of Matter and Energy.
The energy needed to break apart water then produce the hydrocarbons would exceed the energy released from burning hydrocarbons.
Posts: 201 | From: Toronto, ON | Registered: Jun 2006
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Your formula was H2 + CO2 + Energy. The question is how much energy will you need to to sythesize the fuel and will the energy input be greater than the energy that you would receive from burning the fuel. Where would you get the H2? How much energy would that process require?
Why not bypass carbon and produce Hydrogen from electrolysis of water? That has been suggested. But the energy yield is low. There is a higher energy yeild from producing Hydrogen from chemical reactions. These however cause the release of CO2. http://www.motherjones.com/news/outfront/2003/05/ma_375_01.html
Honey Bun "I want to start a company on this idea" ching Oats
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posted
Synthetic gasoline has been around since at least World War II, when the Germans developed the Fischer-Tropsch process. CO2 is not a good starting material, but you can use methane or other carbon sources.
Nick
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Why is everyone hung up on net energy, you do not net any energy from hydrogen production. The problem with hydrogen as a fuel is low power density. Not enough range. Also there is no infrastructure for hydrogen, there is for gasoline. There's also the further advantage of taking the carbon from the atmosphere.
The vision is to have a distributed gas producing system with small synthesizors scattered about where there is solar or wind farms. That Fischer-Tropsch process looks like it would do the trick. Now all I need is a few billion in capital investment.
Posts: 62 | From: Raymond, NH | Registered: May 2005
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quote:Originally posted by Dive_Cecil: Why is everyone hung up on net energy, you do not net any energy from hydrogen production. The problem with hydrogen as a fuel is low power density. Not enough range. Also there is no infrastructure for hydrogen, there is for gasoline. There's also the further advantage of taking the carbon from the atmosphere.
The vision is to have a distributed gas producing system with small synthesizors scattered about where there is solar or wind farms. That Fischer-Tropsch process looks like it would do the trick. Now all I need is a few billion in capital investment.
Well, let's look at the math. Gasoline contains 32.4 MJ/L of energy. CO2 and H2O, both ashes, contain zero. Let's say a typical gas station sells 10,000gal/day, or about 35,000L/day. So it has to output 1.134TJ/day (that's Terra-Joules!). A typical solar panel in California can produce about 20.7MJ/m2/day. So, even if your process was 100% efficient, a typical gas station would need 55,000 square meters of solar cells (13.5 Acres!). And that an overly optimistic estimate...no process is going to get even close to 100% effiency.
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