More evidence hydrogen fuelled vans could power future motorhomes?

[Markman]

Yup because it dispels the myth that Hydrogen will immediately explode or catch fire when exposed to air.

I don't agree. In an earlier life I reviewed a database of over 10,000 loss of containments of, mainly, hydrocarbons but it also included about 140 releases of hydrogen (a release was defined as more than 10kg). About 50% of those resulted in a fire (often with significant financial losses). The issue with hydrogen is the very low MIE (minimum ignition energy), about 10 times lower than normal hydrocarbons (methane, propane, etc, i.e. natural gas). This means that the static charge arising from a flowing stream of hydrogen released under pressure in to air can exceed the MIE. A major contributor to this is the humidity of the air. There is a larger static build-up in dry air, than moist air. So if it rainy weather an H2 leak won't ignite. In dry weather it will.

Exploding is a completely different issue than igniting. For an explosion you need a deflagation to detonation transition. That arises from congestion so that the expanding gas cannot escape (e.g. in a building) pressure builds up and so the wave front accelerates until detonation. So not all H2 releases will detonate/explode, only those that are contained.

 

[gpat]

It needs a source of ignition like any combustible gas.

Yup because it dispels the myth that Hydrogen will immediately explode or catch fire when exposed to air.

No disrespect but it will take more than your 'experiment' to convince me. Being involved in a fatality directly related to a hydrogen explosion has made me very aware of its dangers. Two men,father and son killed when they used a grinder in an area close to where hydrogen was being vented.

 

[knickam]

Many many years ago we used to do intrinsic safety courses (prevention of Explosions in a flammable atmosphere) where the instructor used to demonstrate by actually creating mini explosions in the classroom.
Definitely nobody sleeping on that course

Basically he had a strong plastic box with a see through front. The back was open and covered with tinfoil to keep the gas or dust in. When it went bang the tinfoil burst and directed the explosion rearward.
There was a spark plug in the box that created a spark at very low voltages.

I won’t go into the intrinsic side of things but there was one demonstration to show the dangers of hydrogen. One side of the spark plug was tied to earth and the other to a metal probe inserted through the side of the box.
Box was filled with an explosive mixture of hydrogen and air.
He then inflated a ballon, rubbed it on his clothes to get a static charge.
Touched the metal probe with the balloon and bang.
He did the same for methane, Propane and a dusty atmosphere (flour) and nothing happened.

 

[Coolcats]

It needs a source of ignition like any combustible gas.

No disrespect but it will take more than your 'experiment' to convince me. Being involved in a fatality directly related to a hydrogen explosion has made me very aware of its dangers. Two men,father and son killed when they used a grinder in an area close to where hydrogen was being vented.

There have been many industrial accidents that could have been avoided such as piper alpha or Buncefield Fukushima and Chernobyl.

Sparks flying by an outlet that has hydrogen being vented will have the same effect as any other volatile liquid or gas being vented Hydrogen is not unique to this.

Any stored energy always has the potential for fire or explosion.

My point being is that in order for Hydrogen (or any other gas for that matter) there has to be a source for it to combust it will not catch fire or explode just because it feels like it ! (And I am not advocating hydrogen or any other gas or fuel be freely released.)

 

[JJ]

I reckon they should do some modern research into clockwork power...

My Tissot 1853 automatic watch just goes on and on, day in day out, month after month after month.

Clockwork... well green and carbon emissions free.



JJ

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[deleted79651]

I reckon they should do some modern research into clockwork power...

My Tissot 1853 automatic watch just goes on and on, day in day out, month after month after month.

Clockwork... well green and carbon emissions free.



JJ

Research into clockwork power? This is a wind up, surely ...

Steve

 

[gpat]

Sparks flying by an outlet that has hydrogen being vented will have the same effect as any other volatile liquid or gas being vented Hydrogen is not unique to this.

Any stored energy always has the potential for fire or explosion.

You are still missing the point. Is it far more likely to happen with hydrogen as it is explosive over a greater range of concentrations than any other gas. It would not have happened with say, butane, as the concentration would have been too low.

 

[knickam]

There have been many industrial accidents that could have been avoided such as piper alpha or Buncefield Fukushima and Chernobyl.

Sparks flying by an outlet that has hydrogen being vented will have the same effect as any other volatile liquid or gas being vented Hydrogen is not unique to this.

Any stored energy always has the potential for fire or explosion.

My point being is that in order for Hydrogen (or any other gas for that matter) there has to be a source for it to combust it will not catch fire or explode just because it feels like it ! (And I am not advocating hydrogen or any other gas or fuel be freely released.)

You are of course correct in what you say and what follows only applies to industrial premises and no impact on domestic situations.
Suppose we have a gas processing plant
There are 3 levels of protection

Containment : Preventing leaks eliminates any risk, This is not possible in the real world as compressor seals or valve stem seals can fail.

Detection : Fire and gas detection to alert operators, Shutdown the equipment and if venting/flaring facilities are available depressure the system.

Secondary protection : This deals with the surrounding area and is designed to eliminate the risk of a spark or high temperature causing an explosion if there is a gas leak. It can be motors, lighting instrumentation or other devices capable of causing a spark or high temperature..

This is done in numerous ways depending on the device. But the design will be based on the gas and zone classification of the area where the gas is being processed.

So if we are processing hydrogen the first 2 protection elements basically stay the same as for hydrocarbons.

Secondary protection will be built to a lot higher standard for hydrogen than hydrocarbons due the greater risk of ignition of hydrogen.

Forgetting about technicalities of the actual process.
A system designed for hydrogen could be used for a hydrocarbon process
But a system designed for hydrocarbons would not meet the required regulations to process hydrogen.

 

[Markman]

You are still missing the point. Is it far more likely to happen with hydrogen as it is explosive over a greater range of concentrations than any other gas. It would not have happened with say, butane, as the concentration would have been too low.

Flammability and detonation are two closely related, but different things. A flammable gas kills people caught within the burning cloud due to the heat produced. A detonation/explosion kills people from both excess temperatures and the overpressure produced (directly from crushing them or from missiles or falling buildings).
Hydrogen does ignite over a far wider flammability range than hydrocarbons but doesn't detonate as often as, say, propane which is heavier than air. Hydrogen doesn't hang around, so as long as it isn't contained (in a house for example).

 

[Markman]

Many many years ago we used to do intrinsic safety courses (prevention of Explosions in a flammable atmosphere) where the instructor used to demonstrate by actually creating mini explosions in the classroom.
Definitely nobody sleeping on that course

Basically he had a strong plastic box with a see through front. The back was open and covered with tinfoil to keep the gas or dust in. When it went bang the tinfoil burst and directed the explosion rearward.
There was a spark plug in the box that created a spark at very low voltages.

I won’t go into the intrinsic side of things but there was one demonstration to show the dangers of hydrogen. One side of the spark plug was tied to earth and the other to a metal probe inserted through the side of the box.
Box was filled with an explosive mixture of hydrogen and air.
He then inflated a ballon, rubbed it on his clothes to get a static charge.
Touched the metal probe with the balloon and bang.
He did the same for methane, Propane and a dusty atmosphere (flour) and nothing happened.

Absolutely, the MIE (minimum ignition energy) for hydrogen is an order of magnitude lower than for propane

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[Coolcats]

I reckon they should do some modern research into clockwork power...

My Tissot 1853 automatic watch just goes on and on, day in day out, month after month after month.

Clockwork... well green and carbon emissions free.



JJ

Trevor Baylis would approve

 

[Coolcats]

You are still missing the point. Is it far more likely to happen with hydrogen as it is explosive over a greater range of concentrations than any other gas. It would not have happened with say, butane, as the concentration would have been too low.

I don't think I am missing the point, Hydrogen may be viewed as more volatile than Petrol which can be viewed as more volatile fuel than Diesel yet....

<Broken link removed>

it’s all academic as it will all cause injury or death and has done since humans have used it.

 

[Coolcats]

Brand New Hydrogen Double Decker Buses Have Arrived In London For The First Time​

20 new buses are not an insignificant investment and are part of the zero emission mix. Writebus did announce partnerships back in 2019 to start manufacturing hydrogen buses and there are other Cities that are investing in hydrogen vehicles be it road sweepers etc.

 

[gpat]

I don't think I am missing the point, Hydrogen may be viewed as more volatile than Petrol which can be viewed as more volatile fuel than Diesel yet....

<Broken link removed>

it’s all academic as it will all cause injury or death and has done since humans have used it.

Perhaps you should enrol on a chemistry course.

Hydrogen is not volatile. It is a gas in it's normal state. Petrol and diesel are volatile liquids.

Because hydrogen will ignite over a high range of concentrations it is much more likely to cause an explosion than most other combustible gases or volatile liquids.

For example if you open propane bottle and light it then you will get a flame. If you open a cylinder of hydrogen and light it you will get an explosion. This is because the combustion will run into the cylinder or tank.

 

[Coolcats]

Perhaps you should enrol on a chemistry course.

Hydrogen is not volatile. It is a gas in it's normal state. Petrol and diesel are volatile liquids.

Because hydrogen will ignite over a high range of concentrations it is much more likely to cause an explosion than most other combustible gases or volatile liquids.

For example if you open propane bottle and light it then you will get a flame. If you open a cylinder of hydrogen and light it you will get an explosion. This is because the combustion will run into the cylinder or tank.

Let’s define Volatile before any one suggests or I actually enroll Ona chemistry course….

What is Volatility?​

A substance is said to be volatile if it boils at a low temperature, changing from the liquid to the gas phase.

As Hydrogen can be stored as a liquid and can change from a liquid state to a gas state it fits the definition of being volatile unless anyone knows any different.

what is really positive is the abundance of Hydrogen and it’s potential uses which include trains buses road sweepers etc and hopefully MoHo’s

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[Coolcats]

For example if you open propane bottle and light it then you will get a flame. If you open a cylinder of hydrogen and light it you will get an explosion. This is because the combustion will run into the cylinder or tank.

Just a thought, and would be with exploring further in that whilst I am not saying there are no dangers with Hydrogen I am not so sure it can be as catastrophic as you say in every case



Hydrogen vs. Gasoline Leak and Ignition Test- which is safer?


2001: Dr. Michael Swain with the University of Miami at Coral Gables attempted to simulate two car fires, one created by a 1/16th inch puncture in a gasoline fuel line, the other by a leaking hydrogen connector. He video taped the experiment to document what would happen if the leaks ignited. As the photos below clearly demonstrate, consumer fears about hydrogen as a transportation fuel would seem to be pretty much unfounded. While the gasoline-fed fire eventually consumed the second test vehicle, leaving it a smoldering heap of charred steel and melted glass, the hydrogen fire was over in less than two minutes and left the hydrogen-tank equipped test car virtually undamaged. In fact, the heat inside the car never got above 67 degrees. Dr. Swain points out in Fuel Leak Simulation that while the gasoline fire started as the result of a simple, small hole in the fuel line, for the hydrogen fire to occur, it would have taken the catastrophic failure of four separate safety systems, all at the same time, a highly unlikely occurrence. Dr. Michael Swain Hydrogen Leak Study (PDF) http://evworld.com/library/Swainh2vga...

 

[knickam]

I don't think I am missing the point, Hydrogen may be viewed as more volatile than Petrol which can be viewed as more volatile fuel than Diesel yet....

<Broken link removed>

it’s all academic as it will all cause injury or death and has done since humans have used it.

You are quite correct but diesel vapours are not present unless diesel is heated, Petrol vapours are present at room temperature.

 

[knickam]

I don't think I am missing the point, Hydrogen may be viewed as more volatile than Petrol which can be viewed as more volatile fuel than Diesel yet....

<Broken link removed>

it’s all academic as it will all cause injury or death and has done since humans have used it.

When you talked about diesel explosions it made me think, As I had never heard of a diesel storage tank exploding I did a bit of googling and found the following,

http://technokontrol.com/pdf/diesel-explosion-tanks.pdf

It is about an investigation into a gas oil storage tank explosion. (basically the same as diesel)

A sample of the contents was required and the operative opened a hatch to lower in a sample on a rope to collect the sample.
While doing this there was an explosion blowing off the roof and starting a fire, Unfortunately the operative was killed.

The investigation found that the ignition source was static from the nylon rope being used to lower the sample device.
If the tank has only gas oil vapour this would not have been a problem as there is not enough energy in a static spark to ignite it.

So why did it explode, Hydrogen!

"The investigation pointed out that the source of explosive mixture in the tank was hydrogen that penetrated with the gas-oil to the tank as a result of non-complete gas-oil stripping with hydrogen at the exit of gas-oil hydrotreating unit."

 

[Steve N Tracy]

So are these hydrogen powered vehicles going to use hydrogen for cooking and fridges or will they still retain lpg, if so they will still need drop vents to get rid of leaking lpg which is heavier then air, so if you get a hydrogen leak under the vehicle the hydrogen which is lighter then air could come up through the drop vents, so in this eventuality will vents in the roof be nessasary, also with all these vans, lorry's etc slated to run on hydrogen which just produces water, where does this water go into the atmosphere to return as rain raising water levels?

 

[gpat]

Let’s define Volatile before any one suggests or I actually enroll Ona chemistry course….

What is Volatility?​

A substance is said to be volatile if it boils at a low temperature, changing from the liquid to the gas phase.

As Hydrogen can be stored as a liquid and can change from a liquid state to a gas state it fits the definition of being volatile unless anyone knows any different.

what is really positive is the abundance of Hydrogen and it’s potential uses which include trains buses road sweepers etc and hopefully MoHo’s

You didn't tell me your hydrogen generator was leaking liquid hydrogen!

Yes of course liquid hydrogen is extremely volatile. We were talking about hydrogen gas though.

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[Coolcats]

You didn't tell me your hydrogen generator was leaking liquid hydrogen!

Yes of course liquid hydrogen is extremely volatile. We were talking about hydrogen gas though.

From what I read the volatility is when it changes state from a liquid to a gas

 

[Steve N Tracy]

From what I read the volatility is when it changes state from a liquid to a gas

The passengers on the Hindenberg would beg to differ!

 

[gpat]

From what I read the volatility is when it changes state from a liquid to a gas

Volatility is the relative rate in which a liquid evaporates as a gas. For example water is not very volatile whereas ether is extremely volatile. Materials that are normally gases at room temperature and that are compressed into a liquid are not normally referred to as volatile, but I guess they are actually extremely volatile.

Hydrogen in its gaseous state is NOT volatile, even by your own definition. You hydrogen generator generates hydrogen as a gas.

 

[uzsnowdrop]

“This is because such users operate a mixed-use cycle, straddling urban and out-of-town use and require a greater range, faster recharging and the retention of the vehicle’s cubic capacity load space.”

They could have just said ‘Vans’…

 

[Markman]

The passengers on the Hindenberg would beg to differ!

But that was flammability NOT an explosion (and being 50m up in the air so a long way to fall).

Hydrogen burns VERY easily, it doesn't explode (resulting in a high overpressure) unless contained.
And if you want more details, try this paper:

This domain has been registered for a customer by nicsell

This domain hyresponse.eu was registered successfully by nicsell due to a customer order and will be moved soon.

www.hyresponse.eu

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[Coolcats]

You are quite correct but diesel vapours are not present unless diesel is heated, Petrol vapours are present at room temperature.

Given the right conditions Diesel can cause an explosion, as can Petrol as can Hydrogen as can Flour.

So it is industry responsibility to ensure all reasonable safety measures are in place, If Hydrogen was so dangerous do you really think that transport authorities would allow the use of it on Public transport?

Is Hydrogen a viable alternative fuel the answer is yes can it be contained and stored safely, industry do this all the time, can it be used by the public for re-fueling vehicles and those vehicles not exploding......well yes.

So is there an issue? Not if all the safety procedures are met in the same way that you use electricity or re-fuelling your car or re-gassing your motorhome.

 

[Coolcats]

.

 

[Coolcats]

The passengers on the Hindenberg would beg to differ!

Theories surround the Hindenburg fire one of which is the material covering the airship and is combustible properties, which is beloved added to the intensity and rate of that fire a terrible accident that we would all hope never to be repeated.

 

[tonyidle]

Given the right conditions Diesel can cause an explosion, as can Petrol as can Hydrogen as can Flour.

So it is industry responsibility to ensure all reasonable safety measures are in place, If Hydrogen was so dangerous do you really think that transport authorities would allow the use of it on Public transport?

Is Hydrogen a viable alternative fuel the answer is yes can it be contained and stored safely, industry do this all the time, can it be used by the public for re-fueling vehicles and those vehicles not exploding......well yes.

So is there an issue? Not if all the safety procedures are met in the same way that you use electricity or re-fuelling your car or re-gassing your motorhome.

One aspect of hydrogen that under many circumstances makes it safer in use is its ability to rapidly dissipate. All the other substances you mention are much heavier than air and under many conditions can become trapped and pool whilst they wait for a spark. Hydrogen, being the lightest element, dissipates very quickly.

 

[Markman]

Given the right conditions Diesel can cause an explosion, as can Petrol as can Hydrogen as can Flour.

So it is industry responsibility to ensure all reasonable safety measures are in place, If Hydrogen was so dangerous do you really think that transport authorities would allow the use of it on Public transport?

Is Hydrogen a viable alternative fuel the answer is yes can it be contained and stored safely, industry do this all the time, can it be used by the public for re-fueling vehicles and those vehicles not exploding......well yes.

So is there an issue? Not if all the safety procedures are met in the same way that you use electricity or re-fuelling your car or re-gassing your motorhome.

Anyone following this conversation, I recommend you follow the clicks through that Coolcats included in their post (I hope my use of the gender-neutral pronoun doesn't invoke the wrath of the anti-woke brigade, just being polite since I don't know their gender) . . . they take you to the excellent HSE's web site.

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