too much oxygen

[Dan5]

I don't think anyone's pointed if it's made from water, consider the reaction
H20 -> 2H2 + O2

Now consider a day with no wind. You'll have areas with higher O2 concentrations which could have a detrimental property and environmental effect; flammability (more O2 in the air means greater chance of flammability), plant life, water life (dissolved O2 in the water), and animal life (insects love high O2 levels)

 

[doug]

ehh... you kinda went of the edge at the end there.

 

[rabar10]

Agree w/ doug. O2 is valuable, they would capture and sell it just like the H2. Total non-issue.

I think the infrastructure required for hydrogen is going to be a huge hurdle.
Also it is not as efficient as EVs in terms of energy usage.

These are the valid arguments... :smile:

 

[Dan5]

ehh... you kinda went of the edge at the end there.

What I meant was generation of at source hydrogen using water as the feed stock means that you will also be generating at oxygen at the same source.

Yes, it is valuable currently, but if you are producing it on a large scale the value greatly diminishes (kind of like calcium carbonate in CO2 scrubbers, when that process was widely used the market price significantly dropped for calcium carbonate) and there are more effective ways to produce O2.
I doubt it will be collected when it is no longer cost effective because the general public perceives oxygen as safe.

 

[Lloyd]

What I meant was generation of at source hydrogen using water as the feed stock means that you will also be generating at oxygen at the same source.
Technically oxygen is heavier than air and if you are using wind dispersion as your sole method of dispersion, that's not a good control.

Most people do not think of oxygen as a pollutant, but high levels are dangerous, called oxygen toxicity.

Not an issue! You better not live around too many plants!!

 

[Robert.Boston]

What I meant was generation of at source hydrogen using water as the feed stock means that you will also be generating at oxygen at the same source.

Yes, it is valuable currently, but if you are producing it on a large scale the value greatly diminishes (kind of like calcium carbonate in CO2 scrubbers, when that process was widely used the market price significantly dropped for calcium carbonate) and there are more effective ways to produce O2.
I doubt it will be collected when it is no longer cost effective because the general public perceives oxygen as safe.

As noted above, the O2 will be a valuable by-product, not a waste product that will be dispersed. Both gases would tanked and sold.

 

[doug]

I hope Dan5 realizes that combustion (and fuel cells for that matter) consume oxygen. Also unless you live under a dome, thermodynamics works to eliminate concentration gradients (to lower the chemical potential).

 

[Dan5]

I think we are getting off topic I apologize.

Yes, I realize the O2 will probably be collected and if not that there will be dispersion.

I do agree that combustion vehicles use O2 and there should be dispersion.

I'm trying to think in terms of failure mode analysis (think and prepare for the worst)

Will it significantly raise the % O2 in a certain are?- probably not as long as everything functions correctly.

I would just like to see the % O2 levels in the general vicinity of the hydrogen generator if its freely vented (as a worst case scenario, maybe a valve fails, maybe the O2 oxidizes the metal years later, hose breaks, maybe the valve is left open, maybe a vandal strips the copper valve off to O2 part, etc, etc- who knows) and how far away a person has to be from the source to not be affected. That's part of any failure mode and analysis test (FMEA). I want to know for this worst case, is the "zone of death" from the source 1 inch, 1 ft, 10 ft, 100 ft, 1000 ft, 10000 ft?


I can speak from a similar FMEA that I had conducted on a chlorine railroad tank if anything happened: Worst cases a good half mile had to be evacuated.

 

[doug]

Zone of death from oxygen?? You realize we breathe that stuff, right? And it's more that 20% of the atmosphere??

Chlorine is something else all together. By itself it's toxic and highly reactive. If you breath chlorine gas, it forms HCl in your lungs.

I suggest you calculate, as an exercise how much water you'd have to separate to get enough O2 to raise the oxygen levels of a small town by 1%. (Then also consider you wouldn't actually be able to keep the extra O2 from spreading outside the town.) Consider how much coal you'd have to burn to raise CO2 levels by 1%.

 

[markwj]

I believe you need to get the O2 concentration up above 50% for >24 hours exposure before you need to start worrying about pulmonary effects. Below that, we don't even bother tracking exposure, When diving, we don't start worrying about oxygen concentrations (mostly central nervous system concerns) until partial pressures exceed 1.4 or 1.6 ATA of O2 (equivalent to 140% or 160% O2 at the surface). Medically, it is a non-issue at atmospheric pressure and fraction of O2 below 50%. Similar for hydrogen - you can breath it just fine at levels well beyond where it would explode!

The bigger issue is flammability, particularly in enclosed areas. High levels of O2 makes things burn at lower temperatures. Tanking the O2 at high pressures is just another set of risk factors.

My concerns with hydrogen production have always been around the logistics of high-pressure handling of these two gases. Hydrogen burns easily, and oxygen helps other materials/gases to burn much more easily.