Pulsation Bottles for a Compressor Cylinder 4

[Optimustang]

HI,

I am fairly new to packaging of reciprocating compressors. I am wondering, What size of compressor cylinders need pulsation bottles on them? I am talking about a 10.5" (to 13")bore first stage cylinder and smaller 2nd and 3rd stage cylinders. I have been looking all over the internet to find if there is a design criteria for packaging reciprocating compressors with or without pulsation bottles, but had no luck.

For this specific case, the stroke is 3.5" and biggest cylinder bore is 10.5". I would be really glad if you guys can answer these question, based on your experience/knowledge. OR atleast guide me in the right direction:
1. Is there a industry standard for the size/stroke of cylinder determining the need of pulsation bottles?
2. Do I need pulsation bottles for my case with 10.5" bore cylinder, assuming all piping is fairly oversized.

3. I am design engineer, and have designed compressor parts in past and never worked with pressure vessel designs...So, to be able to design a pulsation/volume bottle, what would be good starting point...any reference material? book?

Thanks in advance.

RJ

 

[DLite30]

Yes, essentially all reciprocating compressors need pulsation bottles.

API 11P (which is now ISO 13631) has guidance for preliminary sizing of the bottles, but I would just use that as a guide, and not a design standard. But some packagers use this as a guideline.

As a customer, we usually require that a Design approach 3 in accordinace with API 618 be followed, which is essentially a pulsation and mechanical study.

Beta machinery has some good articles on their web site. The GMRC used to publish free refernces, but I think they charge for them now.

Here's a good reference list from the folks at swri.

http://www.swri.org/4org/d18/mechflu/pulsat/pubs.htm

Sounds like you have a lot to learn.

 

[Optimustang]

Thanks for your reply. I totally agree with the part that I have a lot to learn. As you suggested, I will begin with Beta Machinery website and SWRI articles.

Also, on the other hand, the place where I started working recently have been packaging recips for a long time. They have pulsation on 10.5" bore and above cylinders but DO NOT have any bottles on compressors with 7.5" first stage cylinders. On these 7.5" ones there is no vibration at all. But these cylinders have orifice plates on suction and discharge side of each cylinder.

And NOW, I wanted to see if we can get away without any pulsation bottles on 10.5" ones (just like 7.5" cylinder packages). In the past these units have had bottles on them, but as I said earlier, I was trying to see if they were really needed (to reduce cost).

Thanks again...

 

[Optimustang]

EDIT: They have pulsation BOTTLES on 10.5" bore and above cylinders but DO NOT have any bottles on compressor

 

[DLite30]

Even with pulsation bottles, sometimes you'll see orifice plates used. Simply because the bottles are intended to act as a notch filter, and cannot filter gas pulsation effectively enough over the entire expected range of pressure conditions. So, orifice plates become somewhat of fudge devices to control some of the "outlying" conditions.

I have seen small compressor sets with small cylinders (4" and smaller) with piping swaged up a couple of sizes to kind of act as a filter. And that can work if the machine operates in a very small, controlled window of pressure conditions.

Here are some more articles for you from EDI.

http://www.engdyn.com/resources/category/technical_publications

 

[Optimustang]

One more Question. Its about the orientation of a pulsation bottle on a cylinder. On all the reciprocating compressors I have seen, the suction bottle is arranged in such a way (looking from the top) that the length of the bottle is perpendicular to the piston rod of compressor. Based on the theory, I am sure that bottle orientation shouldn't matter, but just wanted to clarify....

Thank you.

 

[DLite30]

No, acoustically, it doesn't really matter which way their oriented. The bottles are just physically oriented to a way that fits the machine.

On multi-stage machines, sometimes the bottles may have to be oriented parallel with the piston rod, just to physically avoid the bottle of the adjacent cylinder.

 

[Optimustang]

DliteE30, Thanks for a quick reply. I looked up the video you posted of ROW blasting, it is cool.

 

[Optimustang]

I want to know the procedure to design a vertical separator vessel which sits upstream of every stage in a compressor. I know it depends on the gas velocity and resident time of the gas in the vessel, but I don't know how to calculate them and put them to use.

Sir DliteE30, can you please help?

 

[TD2K]

Optimustang, you should start your own thread rather than tagging your question in an unrelated thread, you'll get better answers.

The GPSA data book has a good summary of sizing upstream separators. Basically, you calculate a maximum gas velocity that will allow liquid droplets to settle out to the bottom of the vessel. The maximum gas velocity along with your gas flow sets the diameter. The height is set to provide enough liquid surge volume and for control and to provide room for internals, nozzles, etc. 3 phase separators are more complicated but the approach is similar.

There's a good paper on sizing 2 phase and 3 phase separators by Svrcek and Monnery. Googling two phase separator (and 3 phase) will get you lots of hits.

 

[Optimustang]

Thanks TD2K. I will try to find that paper, you mentioned. I am strictly looking at 2 phase separators...

Also thanks for the advise, I would have started a new thread to begin with... But its never too late...