Comments on: How Hot Is Your Car Exhaust And Which Way Does It Point?

By: Shocked

Shocked — Sun, 08 Nov 2009 20:19:39 +0000

I was responding to one commenter’s concern that water resulting from hydrogen oxidation, whether through combustion or fuel cell technology, would contribute to global warming. I should amend my comment to say that regardless of how much new water is created, the concentration of water in the atmosphere will reach an equilibrium quickly, and excess will precipitate out.

Your description of H2 production from methane is entirely correct, but I believe the long term goal of hydrogen gas sourcing is indeed from electrolysis, as it is simply more energy efficient to simply burn methane in a turbine and produce electrical energy rather than the convoluted process of extracting H2 from CH4 then transporting it, etc.

I should note that there are non hydrogen fuel cells in development, which extract the hydrogen in the fuel cell system.

By: BBB

BBB — Tue, 03 Nov 2009 19:53:30 +0000

A few things:

Shocked, I want to get to the bottom of your comment

“As for the argument against hydrogen fuel cell technology by one commenter, you’re argument is ludicrous as hydrogen gas isn’t taken from natural supplies, but from the electrolysis of water.”

1. I’m unclear what part of this conversation you’re referencing to about hydrogen coming from natural supplies.

2. You’re also saying that hydrogen comes from electrolysis, which is truel, but leaving out a few things…

Predominately (commercially), hydrogen is formed from steam reforming of natural gas (much cheaper than electrolysis):

CH4 + H2O → CO + 3 H2

& then

CO + H2O → CO2 + H2

If you consider natural gas (essentially methane) to be a ‘natural supply’, then yes, most hydrogen comes from natural supplies. Unfortunately the cheapest (currently) formation of hydrogen results in CO2 &/or CO….

My rant:

Longterm, if hydrogen is to be a viable alternative for fuel, it needs to be produced pollution free (wind electrolysis?)…. or at least at a rate below the earths ability to ‘metabolize’ the pollution (CO2 getting sucked up by plants).

Thoughts?

-BBB

By: Shocked

Shocked — Sat, 31 Oct 2009 00:36:01 +0000

I think your heart is in the right place, but this article shows a severe lack of physics knowledge on the part of the author. Though many processes create heat on Earth they are absolutely insignificant when compared with the heat that the sun imparts, and the Earth is continually radiating energy into space. The rate of temperature change on Earth is essentially due to the difference between heat entering Earth (Sun, cosmic rays) and heat leaving (EM wave energy), which is a function of cloud cover (as the sun’s output is basically constant) and the greenhouse effect.

As for the argument against hydrogen fuel cell technology by one commenter, you’re argument is ludicrous as hydrogen gas isn’t taken from natural supplies, but from the electrolysis of water. Water dissolved in air (humidity) maintains an equilibrium based on many factors; excess results in precipitation.

As a university physics professor I am very concerned with global warming, but don’t put your blood, sweat, and tears into a cause based on original research or intuition. I apologize for some of my vitriol, but over the years I’ve seen, time and again, use precious time and money fo insignificant causes.

By: jeff

jeff — Mon, 30 Mar 2009 16:48:59 +0000

ya but the thing about water vapour is that at a certian point when the concentration becomes to high it starts to rain and then the percentage of water vapour in the atmosphere is greatly reduced so really the only thing that additional water vapor in the sky will do is make alittle more rain

just another argument for more hydrogen powered vehicles