FIRE FROM MOLTEN POLYMER

[tmc1]

Hello,
My plant produces high density polyethylene and the final product is pelletized resins after extrusion.
My problem is that when the molten polymer is exposed to atmospheric air, it catches fire. Last week, it happened again, and this time the extruder die plate caught fire although very small fire. Keep spraying with water is one of the solutions but that not only wasting a lot of water but also messy and labor intensive. Can anyone provide a better and practical solution like some process control or changes in operating conditions. Or something else.
Appreciate your guidance.
Thanks.
Chng,TM

 

[DickRussell]

I have no particular experience with polymer handling, but I do wonder what is catching fire initially, given the almost zero vapor pressure of the polymer chains. The only thing that comes to mind is residual unpolymerized monomer, exposed to air above the flash point, catching fire and igniting the polymer. That would lead one to think that better devolatilization of the polymer prior to extrusion or better venting in the area around the first exposure to air (or inert gas blanketing) would help.

I would think that others with direct experience would have encountered this problem before and will be able to help with specific recommendations. HTH

 

[MikeHalloran]

A die plate submerged in a tank of water wouldn't catch fire.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[StoneCold]

tmc1
You need to determine the root cause of the fire. Is it monamer? Is it the extrusion temperature? Is it non explosion-proof equipment in the area? You have been lucky so far, your operators are on the ball and don't run when they see a fire. You need to get to the root cause and solve the problem before the fire ignites any polymer dust in the area and you all go up in smoke!.

Goodluck
Stonecold

 

[tmc1]

Sorry if my question is not clear enough.
It caught fire when the die plate was under maintenance and the die plate chamber door was open.
Thanks guys for your response.
tmc1