The difficulties with burning hydrogen in a conventional engine.

[Stan]

The facts come fast in this video. Are you ready?

[Stinsy]

I haven’t watched the video (yet). However this is an interesting topic. It really annoys me when journalists (BBC/Gruniad seem to be worst offenders) claim that the only product of burning Hydrogen is water. This can be a contentious issue, in fact a moderator from another forum threatened me with a permanent ban for explaining that Hydrogen Peroxide would always be a product of burning Hydrogen (that is how H2O2 is manufactured!). While I’m not an expert, and couldn’t comment on the quantities, there is the clear and obvious possibility of Ozone, Nitrogen Oxides, and other nasties being created if you’re burning hydrogen in an internal combustion engine.

To be clear: anyone claiming that the only product of burning Hydrogen is water is either misinformed or is lying to you.

[spread-tee]

To be fair though any fuel burned in an ICE will produce some of those pollutants it's not particular to H2. Personally I wouldn't be too worried by a bit of H2O2 in the exhaust, it would soon be reduced to water and Oxygen by any other reducing agents, in a dilute solution it is used to clean wounds and as a mouthwash.

Desp

PS interesting video, lots of concise info without the hot air. Good one.

[nowty]

If you don't want to watch the whole thing, the general gist is if you want to use hydrogen in cars, your better off using a fuel cell powering an electrical motor, than trying to convert or re-invent a hydrogen ICE. It pretty much dispels the myth that its an easy conversion like it is for LPG.

[Bugtownboy]

I haven’t watched the video (yet). However this is an interesting topic. It really annoys me when journalists (BBC/Gruniad seem to be worst offenders) claim that the only product of burning Hydrogen is water. This can be a contentious issue, in fact a moderator from another forum threatened me with a permanent ban for explaining that Hydrogen Peroxide would always be a product of burning Hydrogen (that is how H2O2 is manufactured!). While I’m not an expert, and couldn’t comment on the quantities, there is the clear and obvious possibility of Ozone, Nitrogen Oxides, and other nasties being created if you’re burning hydrogen in an internal combustion engine.

To be clear: anyone claiming that the only product of burning Hydrogen is water is either misinformed or is lying to you.

I can accept that ‘burning’ H2 in an air aspirated engine may generate other exhaust gases other than water, what is your actual point about other ‘contaminants’ ?

So, you are actually proposing that burning hydrogen, in atmospheric air/oxygen, produces significant quantities of H2O2 ?

Be interesting to have a quick synopsis of the industrial production of H2O2 too (lot of too’s there) in simple terms.

[Oliver90owner]

‘Fraid fuel cells beat ICE all ways round. They have done for decades and will in the future - except on cost.

Points not taken up are complex gearboxes needed for ICE, no energy recovery like current BEVs, servicing costs, brake component wear, noise (abated by a necessary exhaust silencer system, the need for a CAT. Probably others.
A KERS system is likely needed, so a battery, so self-charging hybrid technology included as well - so might as well use fuel cell technology like thebRiver Simple cars.

As I see it, it is only the cost of fuel cells which may be a problem, currently (apart from the availability of green hydrogen at low efficiency and ,therefore, high cost).

There may be some installations where burning hydrogen is useful, but for cars, it seems less and less likely.

[AE-NMidlands]

To be clear: anyone claiming that the only product of burning Hydrogen is water is either misinformed or is lying to you.

I can accept that ‘burning’ H2 in an air aspirated engine may generate other exhaust gases other than water, what is your actual point about other ‘contaminants’ ?
So, you are actually proposing that burning hydrogen, in atmospheric air/oxygen, produces significant quantities of H2O2 ?
Be interesting to have a quick synopsis of the industrial production of H2O2 too (lot of too’s there) in simple terms.

Maybe it does... It is worth exploring or asking for an explanation of the consequences of using H2 in an ICE - what type, by the way? As I understand it:
Petrol engines (spark ignition) have relatively low cylinder temperatures and pressures, so they might /usually produce CO, whereas diesel (compression ignition) has such a high combination of T and P and surplus oxygen that the atmospheric nitrogen reacts too, giving NOx which is not generally present in petrol engine exhaust.
I once ran a job where a supplier of a high-tech landfill-gas incinerator wanted to show how much cleaner his device was than a simple flare. We used FTIR analysis to analyse the LFG and the exhaust to demonstrate to the EA that the new burner was much cleaner than the ordinary flare it was installed beside...
They were absoulutely shocked to see how much N₂O was in both exhausts... Apparently it is known that N₂O is a serious greenhouse gas, but because it is difficult to measure by traditional wet chemistry none of the permits include limits for releases!
A

[Stinsy]

Be interesting to have a quick synopsis of the industrial production of H2O2 too (lot of too’s there) in simple terms.

I’m not an expert and my A-level chemistry was many decades ago, so I’ll do my best and am happy to be corrected by someone better informed,

These days commercial manufacture of H2O2 is undertaken by hydrogenation using a palladium catalyst.

However we made H2O2 in the lab by burning Hydrogen with Oxygen. There are two mechanisms by which H2O2 is produced (in addition to water). The first is where a hydroperoxyl radical (HO2) reacts with H2 to form H2O2 and a Hydrogen atom. This part you cannot control, it happens at the same rate nomatter what you do. The other mechanism is where two hydroxyl (OH) radicals combine, this one you can improve significantly by having the reaction occur in a glass container that has the walls cooled by running water over them. The whole point was to try to make as much Hydrogen Peroxide as we could, how to burn hydrogen while making less H2O2 wasn’t discussed.