8 replies to this topic

[Rahimzadeh]

Dears:

Please tell me that every refractory before start up must be cured?
Best
M.R.Rahimzadeh

[TS1979]

Yes. That's right. Every newly installed refractory must be cured to avoid refractory cracking.

To cure refractory, you need to control the heating speed. Normally, the heating speed shouldn't be over 200°F/hr. You can contact furnace vendor for refractory dry-up procedure.

[adriansyah]

Dear Mr.M.R Rahimzadeh

I am agree with TS1979, every refractory lining especially for monolithic castable lining has to cured for 24 hours minimum before dry-out process. The purpose of curing process is to make sure the hidration reaction on the castable system has been completed & the water excess will be released on dry out process. Water Release process is important to avoid lining crack.

Thanks

[Rahimzadeh]

Dears
thank you for sharing with me in this ropic.

[breizh]

The key is to get input from the vendor depending of the type of material ( silica , alumina) , they will tell you how fast you can dry the refractory .


attached an example :
http://www.insulatio...cfm?id=IO100301

Hope this helps
Breizh

Edited by breizh, 09 August 2012 - 01:03 AM.

[kkala]

Agreeing to previous posts, I would like to add that extensive care was given in writing the "dry-out procedure" of a new crude still heater in a local refinery (2011). The writing was based on Vendors data (though Contractor had a general knowledge out of experience). Vendor would give the drying curve to show max temperature in radiant section versus time. According to it, temperature was increased by a constant rate, remained flat for a few hours, then similarly increased further, etc. So, at least in theory, all heater instrumentation should be ready for correct function before realizing the procedure. Time of heating lasted about two days, followed by a similar time of cooling.
I have not participated in the "dry-out", neither have I accomplished the procedure; but I remember from general reading that minor damages on the refractory are quite usual, followed by repairs afterwards. The whole task was in heater Vendor's responsibility and supervised by it.

Edited by kkala, 09 August 2012 - 01:34 AM.

[Rahimzadeh]

Thanks a lot:
Unfortunately we have not any data from vendor.
In our document just written castable insulation.
My question is that is possible refractory made from special polymer ?

[kkala]

... My question is that is possible refractory made from special polymer ?

I have not heard of that. Despite my limited experience, I suppose it would be too costly for general industrial applications (if there is), http://en.wikipedia....wiki/Refractory '> http://en.wikipedia....wiki/Refractory .

[Dacs]

You have to obtain that information from the vendor. They're in the best position to tell you how fast the curing rate is.

Otherwise you're risking refractory damage before you start your plant!

Different refractory makeup will require different curing times.

The whole task was in heater Vendor's responsibility and supervised by it.

Check your contract with the vendor. I expect that a specialist from the vendor to be present during startup to supervise commissioning, and it's normally a part of the obligation of the vendor as per your contract with them.