Hydrogen fire at Golden Empire Transit demolishes bus, tanks explode .... 7

[MJCronin]

https://www.msn.com/en-us/news/us/h...hes-bus-cause-under-investigation/ar-AA1e2Izs

https://www.kget.com/news/local-new...n-central-bakersfield/?ipid=promo-link-block1

MJCronin
Sr. Process Engineer

 

[LittleInch]

The other issue with hydrogen is that the ignition energy is about 10% of that for methane, so even static electricity is enough or the smallest spark which otherwise you wouldn't see do anything for methane or LPG.

The pressures you need to store hydrogen at to make commercial sense for things like buses is huge. That's why everyone is trying to find a non super high pressure way of doing it, but no one is there yet...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[resqcapt19]

Houses have pilot lights so the flash point is of concern.

I believe you mean autoignition temperature. Flash point only applies to liquids per NFPA 30.

3.3.21 Flash Point (FP).
The minimum temperature of a liquid at which sufficient vapor is given off to form an ignitible mixture with the air, near the surface of the liquid or within the vessel used, as determined by the appropriate test procedure and apparatus specified in Section 4.4.

 

[TugboatEng]

Natural gas certainly has a flash point. It's just not a liquid at any temperature we are familiar with. Under normal atmospheric conditions it's always well beyond it's flash point.

 

[1503-44]

https://www.swagelok.com/en/blog/hydrogen-valves-what-to-look-for

https://www.energy.gov/sites/prod/files/2014/03/f11/871916.pdf

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[enginesrus]

ugly fossil fuel...

No such thing. That is a special "catch word".

The earth is Co2 neutral. None of it has been brought here by man, from any other planet or body in space.

 

[resqcapt19]

Natural gas certainly has a flash point.

Of course it does, but I just don't understand your comment about houses having pilot lights as I am not aware of any house supplied by liquid natural gas.

 

[TugboatEng]

The pilot light is a source of ignition present in many houses. Flash point ignition requires a spark or flame. Obviously the nat gas delivered to homes is above the flashpoint at all times.

There are not many exposed ignition sources on a vehicle. Therefore, the flashpoint is less relevant. Autoignition starts most fires on vehicles.

 

[1503-44]

H2 has plenty of ignition sources. Don't slide across the seat covers.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Pilot lights went out of fashion / use over 30 years ago. Waste of energy and had an annoying tendency to go out....

Everything has been piezo ignition spark either within the boiler (furnace) or push button on a gas stove.

Flash point and ignition temperature are two different things as is ignition energy. ignition temp for methane and hydrogen is about 1000F / 600 C

Ignition energy is about 0.02J for H2 and 0.2J for methane / propane etc.

"static" spark is about 0.02J....



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[davidbeach]

Gas water heaters still use pilot lights.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[3DDave]

Yup - my gas water heater has a pilot that is used to drive the thermopile that operates the valve and the little LED that blinks to little benefit as I am only going to check it if there is no hot water at the tap. It's possible that power-vent water heaters have a transformer to provide that power.

 

[1503-44]

You guys should switch to on demand, tankless, no pilot heaters.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[TugboatEng]

As the electric grid gets less reliable I think many are going to regret the tankless choice.

 

[JohnMcNutt]

I read that, back in the day (as late as the 1950s), places were still supplying town gas/water gas/coal gas/producer gas/city gas to houses. It was supplanted by NG by the 1960s.

Made by quenching some sort of burning carbon solid with water in the absence of air, which made hydrogen, carbon monoxide, and some useless gases, but good enough to burn in the home for fuel.

Did all that CO cause thousands of deaths due to leaks? Did the H2 leak out of pipes? What kind of pipes and metering were used with that gas anyway? What equipment burned it?

There seems to be precious little information on the old town gas systems available now, even though it seemed widespread at one time.

 

[1503-44]

LPG no E required. Well, OK, just 1 C cell.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[waross]

Co2 neutral

The earth is Carbon neutral.
The earth is Oxygen neutral.
CO2 is created when Carbon and Oxygen combine.
The earth is NOT CO2 neutral.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[SWComposites]

actually, earth is not oxygen neutral; some leaks out of the atmosphere into space

 

[waross]

You guys should switch to on demand, tankless, no pilot heaters.

Been there, done that, don't want to do it again.
I have had unsatisfactory showers in South America, Central America and in North America,
I hope to never experience another almost on demand hot water heater.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[1503-44]

They were not properly sized. You just need a larger capacity. All 3 of mine will easily reach 70C. I've have to dial the fire down to keep them safe to use.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[zeusfaber]

What kind of pipes and metering were used with that gas anyway? What equipment burned it?

I can remember some of my relatives being converted to "High Speed Gas" from the North Sea in the late 1960s (we didn't have mains gas where I lived). They used the existing pipes and (so far as I can remember) meters. The main change was switching out the jets in the appliances to match the lower flowrate requirement.

A.