Accumulator Vessel Design

Horizontal Vessels - Elevated with Boots

Example: Stripper Receiver, Accumulator, Interstage K. O. Drum, and Flare K. O. Drum

Discussion: These types of vessel will normally be medium to large sized. (6'-0" I D)to 10'-0" ID) They will be mounted to the support surface (foundation or platforms) on traditional vessel saddles. Near grade this vessel will normally be mounted on an elevated foundation. Access is normally required for the Boot operating valves and instruments. The NPSH requirements of the related pumps are critical to setting of the support elevation.

It is important for any piping designer who is assigned the task of doing a horizontal vessel orientation to remember is that the shell is just a short piece of large diameter pipe with lots of branches that spans between two supports. It is not a grand mystery. In order to know and do vessel orientation, you just need to know the vessel nomenclature, the parts and the attachments. You must also know how to read a P&ID and understand what it is telling you. Then, you must be able to transcribe the P&ID requirements and the vessel pieces, parts and attachments into a correct, functional and safe design.

For this type of vessel it is important to remember that this is not just a "wide spot in the road" where a liquid collects and waits before moving on. Process action occurs in almost every vessel in every plant. Two types of process action will happen in this Overhead Accumulator. First, liquid sour water will separate out of the liquid hydrocarbon. The water may have been entrained in the Crude or may come from condensed steam that was injected into the Fractionator that is upstream of this vessel. Second, hydrocarbon vapor will separate out of the hydrocarbon liquid. No matter what, this vessel must do its job. You must know and understand what that intended job is. You do not need to be a process engineer but you should be involved in the review of the P&ID for this specific vessel. You need to hear what the critical issues are relating to this vessel and the connected piping. If your company does not include piping in the formal review of the P&ID's then you need to seek out the process engineer and ask him or her to explain the function, key points and any critical issues relating to this vessel.

As for the optimum sizes you need to consider the minimum process flow against the maximum shipping size allowable.

Thank you very much for the detailed write up. That is exactly what I am looking for. Your conditions are correct and the usage as well. I am aware of the proces engineering aspects of the vessels and able to use P&IDs fully. I can retrieve all the properties and proper info for the design from the Hysis and Pro II H&MB.

I would like the help to design the vessels, Vertical and horzontal with proper supports. There have to be some spread sheets readily available.

Regards;

Nadeem

We have a couple large (30'OD x 60" high) accumulator tanks that are used to condense and separate fiber, water and vapor in the paper mill I work in. The vapor created by blowing cooked pulp from a digester into a blow tank gets carried over to a accumulator where the blow heat water is collected and reused. This accumulator also has a barometric condenser on top of it and it was all designed for 7 psi max rating. I think you may be referring to a pressure vessel though in a hydrocarbon type set up.

Thanks for the note, Pipewelder.

No, my requirement is what pennpiper explained in his detailed write up and I am still looking for the spread sheet to calculate the sizes.

The vessels are to be used in the refinery and chemcial plants.

Regards;

Nadeem

You might get some help here:

http://www.hansontank.com/

and here

http://www.1728.com/cyltank.htm

Thank you very much for the response.

After today, I will not be available at this computer.

I am leaving the company.

Regards;

Nadeem

Nadeem0430@hotmail.com

Ouch, seems you lads just gave Nadeems former employer some opposition! LOL

No, the company is having problem getting jobs. We are in the refinery and chemical plant business. A small EPC company in Houston area with about 260 people. The management decided to build up the company too fast and fell flat on it's face when the hard times came around. They were hiring process engineers as near as last month and now they had choice to keep they wanted and let the others go who were expensive and had more experience. That is life. I am not bitter. They were justified economically and from the business point of view.

I survived the first wave of lay off and then yesterday came the second one. The company has a "all hands meeting: on every1st or seconf Monday of the month and they announced yesterday that 20% staff reduction and cutting back the hours to 36 hours/week. That means about 55-65 people out of about 260 total. Last time it included 3 process engineer among 8 and this time three more process engineers along with many and I was one of the process engineer. So We will be gone this week and we will see who else goes this week and next. The jobs are either delayed, cut back or cancel all together. Every one is in the same boat and no guaranty for job security.

Oh, hell, I worked before here and shall work somewhere else again. This is not the end of the world and the economy will not stay at the bottom forever.

I thank you all for the help over the years in CR4.

Regards;

Nadeem Butt

04142009

Nadeem0430@aol.com

Nadeem0430@hotmail.com