Stripper column reboiler, Delta T 3

[earthdragon69]

I am having troubles retaining upper and lower temperatures in my stripper column. I have tried changing fluid levels, increasing steam, and having very little success at raising my temperatures.

The reboiler has been hydroblasted less than a 6 months ago. Any helpful hints or things I can try to get this operating coorectly at the temperatures I need to properly strip the water from the product?

 

[Chance17]

It is assumed there is a throttle valve on reboiler steam inlet.
If the reboiler is fouled, the pressure downstream of the throttle valve will increase significantly.
You should also check the condensate system to ensure good condensate removal.

 

[katmar]

I agree with Chance17 that the best indication of a fouled reboiler is an increase in the pressure on the steam side. Do you have a steam flow meter? If so, has the steam flow decreased? How does it compare with the design flow rate? If you don't have a steam meter a crude but effective method is to run the condensate into a drum on a scale. Half fill the drum with cold water to prevent flashing, and measure the increase in water mass with time. One thing you should not do is bypass the steam trap on the condensate outlet as that will lower the condensing pressure and temperature and give you less driving force.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[CJKruger]

earthdragon69, if you have water in your stripped product, you can look at the following:

- Reboiler duty. Calc it from steam or condensate flow rate.
- Low top temp. Calc the water dew point overhead to make sure water can leave overhead.
- Vapour to liquid rate at bottom tray. You need a V/L mole ratio of at least 0.3-0.5 to properly strip water or H2S. This becomes a problem when you increase feed preheat too much.
- Lastly, if you control the reboiler duty on outlet temperture, make sure the temperature have a significant change for change in vaporization.

Cilliers

http://www.korf.co.uk

 

[earthdragon69]

All very good and useful information and I do have a fouled reboiler. I also learned that it takes very little film build up on the tubes to insulate steam and foul up reboilers. As I am new to this I learn quickly. Thank you for the great information guys! Or girls! Whichever the case maybe.