Heat transfer problem

[Amrick]

Hi guys,
I am trying to do the pyrolysis at low temperature in an oxygen-free environment. So I use a small container and want to get 250°C on its inside. So I put it in the oven at 250°C and measured the temperature after each half an hour.
After one hour the temperature reached 140°C and did not go any higher (I measured the same thing after 1h30 and 2h).

The container is made of steel with 2mm of thickness, is inert with Nitrogen, and is closed. So I wonder why I have this temperature gradient between inside the container and the oven and why the temperature is not going any higher than 140°C.

Any comment is greatly appreciated.
Best regards,
Amrick

 

[Compositepro]

Measurement error.

One instrument reading Fahrenheit rather than Celsius.

If you are measuring while doing the pyrolysis, the temperature will stay low until the pyrolysis is complete. During pyrolysis heat transfer can be very slow because out-gassing not only absorbs heat, it also carries the heat away counter-current to the in-flowing heat. The container can't be completely sealed or it would likely explode.

 

[LittleInch]

Seems odd, but can you give us a photo or drawing of this item.

Is it truly sealed and hence good for high pressure?

How are you measuring the temperature?

Do you take it out of the oven each time to measure the temp?

We can only see what you tell us whereas to you it is all self evident.

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