High temperature reboiler tubes material

[waliq]

Hi all,

We are working on a reboiler that is basically of AEU type heat exchanger configuration. The shell side has Glycol while on the tube side there is direct firing through burners. The burner shall be directly firing in the channel side through which the flue gases shall be directed to a tube (one single 14" u tube). The tube shall be immersed in TEG.

We are looking for a suitable tube material to sustain a temperature of 1100 Deg C. Can anyone give any suggestions. I have come across two material by the name of HK-40 and HP-40. However, their temperature range is 900 Deg C max. Although the tube temperature is not expected to go beyond 400 Deg C being immersed in Glycol. But, the small portion of tube that is coming out of tube sheet and into the shell may experience a high temperature. Therefore, we are looking for a suitable tube material that is able to withstand such a high temperature. The temperature of burner flu gases is 1400 Deg C.

Is there any tube material available that is designed to withstand such a high temperature?

 

[Dhurjati Sen]

Dear waliq,

Any material that withstands 400[sup]0[/sup]C is used for the tubes and tube-sheets.

The tube sheet towards the flue gas side is covered with castable refractory, while ceramic ferrules wrapped with an hygroscopic material are inserted through the tubes.

Regards.


DHURJATI SEN
Kolkata, India

 

[XL83NL]

What design code are you following, or do you need to comply with? ASME VIII-1 ends at 982°C if im not mistaken. Beyond that, you cant go ASME.
Perhaps API 530 offers some solutions, but since youre talking HEX's im not sure if itll fit your requirements.
I know AD2000 'allows' 602CA to go up to 1150°C by means of VDTuV datasheet 540.

In terms of material suitability, maybe you first need to find a candidate that mechanically meets the design conditions (if possible at all), and then look into the various possible corrosion mechanisms for the alloy under consideration.