Am I at risk of a steam explosion? 2

[cdill21]

Hello All,

I am trying to see if I have a risk of a steam explosion.

I have taken over a legacy product line which is effectively a small (0.5 ft^3) water heater on wheels for industrial use. In this particular unit, I have observed a 30,000 btu/hr electric heater in the system, with a 15,000 Btu/hr 1/2" relief valve.

This is not a passive heater system. It is designed to flush the heater tank with incoming cold water, more than sufficient to dump excess heat from the heater and keep the water from boiling until the operator notices and shuts down the machine. The failure mode is a stuck mechanical heater contactor. The tank itself is designed to a burst pressure of 2000 psi, but as I understand it, CSA only considers systems with a MAWP of 150psi.

In the event of a failure for the system to flush cold water, I am confident that the current pressure relief valve is sufficient to continue to dump steam until the heaters burn out, before the pressure vessel would burst.

Is this a reasonable assumption? T

 

[MJCronin]

Just a thought ...

This could be done at moderate cost ....

What if you took 4-5 production units out to a nearby quarry and forced the accident scenario on them ?

(Be safe... Put distance and perhaps a rock wall between you and the test)

Have you done this already ?

Will they all fail the same way ?.... Will they fail in the way you expect or somehow in a catastrophic manner ?

It was my understanding that the WORST thing that you could do with a steam boiler is to flood it with water after it has run dry and is above design temperature...

Regards

MJC

MJCronin
Sr. Process Engineer