5 replies to this topic

[Arsal]

Hello everyone,

 

Stripping steam to the crude distillation column and side strippers are used to reduce the partial pressure.Currently our stripping steam temperature is 660-670 F, and this temperature is achieved by super heating section of crude heater(by super heating of LP steam @ 30 Psig ) however after Revamp of Heater it seems the steam temperature become reduce to 560-580 F,Can u please explain any major impact on the column/product specification?  As per my understanding if the temperature of stripping steam becomes low u should increase the stripping steam flow rate accordingly.

 

Is any method or reference available to calculate the Stripping steam temperature??what is the recommended stripping steam temperature range?

is it depend upon the transfer line temperature?

 

I would also like to know the safe stripping temperature to prevent condensation in the strippers/columns as condensation may upset stripping trays in CDU column.

Edited by Arsal, 18 March 2016 - 09:40 AM.

[breizh]

Arsal ,

Probably good for you to take a look at a steam properties tables ( enthalpy in particular).

 

http://www2.spiraxsa...Properties.aspx

 

My 2 cents

Breizh

Edited by breizh, 21 March 2016 - 09:30 PM.

[Arsal]

Thankyou for response,I would appreciate if you please elobrate.

 

As steam become superheated after Boiling point temperature.

 

But still my question is the same "I would also like to know the safe stripping temperature to prevent condensation in the strippers/columns as condensation may upset stripping trays in CDU column??." and "what is the recommended stripping steam temperature range for CDU?

 

[Pilesar]

At the temperatures inside your crude distillation unit, look in the steam tables and find the corresponding pressure where condensation occurs. Then find the locations in your CDU where the partial pressure of the steam is higher than that. At those locations, water condensation will occur. Adjust your steam superheat as desired and check the difference.

[Arsal]

As Superheated steam pressure is constant i.e 30 Psig however the temperature could be change as degree of superheat.Same has been depicted in steam table as well.

 

Saturation temperature of LP steam at 30 psig is 274 F. So why we inject high temperarture steam (~ 660 F) to the coulmn?Is there any standard requirement regarding Minumum stripping steam temperatrue? 

 

I am confused regarding stripping steam temperatrue and i found different values  striiping steam temperatrue at dfiferent refineries i.e 650 F, 550 F, 470F and even some refineries used 300 F.

Could any one please elobrate it more for clear understanding?

[Napo]

Arsal,

 

I send information from the book: "Guide To Refinery Operating Cost (Process Costimating)", by W. l. Nelson, 3rd. ed., The Petroleum Publishing Company, 1976, USA, p. 47.

 

Napo.

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