Effluent Seperator 1

[kagadpencil]

I am a rookie engineer. Following are my questions that came to my head as I was reading (studying) a DWG (sketch really) for an Effluent Seperator involved in a refining project.

In a refining operation, what does Effluent Seperator do?
Why is the corrosion allowance for vessel is 0.125, and for boot it is 0.25) - Is the environment, spill etc. around the boot more corrosive ? - Please give me some info.
What is the use of a belly band around the saddle? What is I dont have it?
What are the factors that decide the specification of HIC steel as head and shell material as against regular carbon steel?
How do I decide if I specify full radiograph (RT-1) or spot radiograph (RT-3)?
I see a nozzle for steam out - My question is when operating temperature is around 120 F and operating pressure over 400 psig, how can there be any steam - Would water boil at 120 F at 400 psig? - I dont have steam table infront of me, but I think it wont.

 

[Guidoo]

When I see your post (as well as a similar post in this forum), first thing that comes up is: "Doesn't he or she have a more senior collegue that he/she can ask these questions?". Don't feel emberarrassed to ask these questions to a collegue. In my opinion it is part of your job as a senior engineer to train juniors. I also think that this forum is not really meant for these type of questions (similar to student questions).

Some of your questions I can answer (for example, steam-out is done after the vessel has been taken off-line. Steam is connected to your nozzle by connecting a hose from a utility station and it leaves the vessel via a vent. Purpose is to remove hydrocarbons from the vessel so that it can later be safely entered.) Other questions I cannot answer (e.g. corrosion allowance since it depends on the specific conditions in your vessel).

 

[IFRs]

I think an Effluent Seperator would separate the water from the hydrocarbon liquids and solids. The water would go one way and the residuals re-used or composted.

 

[jte]

I agree with Guidoo... but I have a few minutes left...

Often a boot exists to separate out more corrosive crud like sour water. Thus the higher CA.

If by "belly band" you mean a stiffening ring, then it is there to mitigate the local stresses imposed on the shell by the saddles. Most saddle to shell load analysis is based on work by L.P. Zick. Usually you will only see saddle rings on large, relatively thin wall vessels.

HIC steel decisions will be based on where you are on the Nelson Curve.

Spot vs. full RT is mostly an economic decision. You save a bit on materials with full RT but absorb the costs of a full RT which includes the risk of having to make more weld repairs. This decision may often be left to the fabricators. From my perspective, a Fitness For Service analysis later in life will be easier if I have corrosion away from a weld seam and the vessel has "excess" thickness for me to work with since it was designed with a joint efficiency of 85%. Another consideration would be that a thicker vessel will withstand local loads (from nozzles, pipe supports, platforms, etc.) better.

Steam out has already been covered.

jt