6 replies to this topic

[jcrivasplata]

I´m an Instrumentation Engineer working in the design of a water treatment plant, for a gas extraction and processing site in Peru.

 

There are several storage tanks, from 20 m3 to 350 m3, all of them require blanketing gas in order to avoid oxygen from the process.

 

Using the latest API 2000 (7th edition) guidelines I have determined the normal in-breathing requirement, which will determine the flow requirement for a tank blanketing regulator.

 

The steps I followed are:

(1) determine the volumetric flow rate required to replace the liquid being pumped out;

(2) determine the volumetric flow rate required due to temperature drop;

(3) add the results of (1) and (2) together.

 

I followed similar steps to determine the normal out-breathing requirement, which will determine the flow requirement for a vapour recovery regulator.

 

(1) determine the volumetric flow rate required to compensate for the liquid being pumped in;

(2) determine the volumetric flow rate required due to temperature rise;

(3) add the results of (1) and (2) together.

 

At this point, I guess, what is next with the Blanketing regulators is to determine the Cv requirement for these devices, but I don't know how to do it exactly. Could anybody please provide some further information?

 

In addition I also need to do some calculations and size the Pressure Vacuum Relief Valves (2 installed in each tank) I found some calculation steps on the internet but they require the Discharge Coefficient, I also read that a typical value for this coefficient is 0.65. I also need to determine the proper size for these elements. Any advise whit this issue?

 

The last device I need to size is the Emergency Relief Vent (with vacuum). With this device, I think, the first step is to to determine the emergency venting requirements for fire exposure. (following the Table 7/8 from API 2000). Besides the emergency venting requirements, what's next in order to calculate the proper size of this device? 

 

I have to deliver a Calculation Report for each device so it will be very helpful a couple of advises (or more).

 

Thanks in advance for your time.

 

Regards

 

Julio

[fallah]

Julio,

 

For all blanketing regulators, PVRV's and EV's you need to report the pressure/vacuum relief loads including in relevant data sheets and leave the sizing to be done by reputable vendor(s)...

Edited by fallah, 09 April 2016 - 04:02 AM.

[Art Montemayor]

Julio:

 

The expert advice that Fallah has given is the standard procedure(s) followed by practically all process design engineers.  The actual sizing and type of relief device to be employed on storage tanks is left up to the device manufacturer who is in a better position to analyze and judge what device fits the application based on the basic data supplied and the devices available.

 

What is important is that you furnish the manufacturer(s) with a detailed Data Sheet citing all the important basic data regarding the application.

 

There is a lot of information regarding this topic in many threads found in our Search Engine.  Additionally, I am furnishing some documents that may be useful for you - especially a series of excellent articles authored by no other than our expert tank venting specialist PAUL OSTAND.   Paul is well-known in the industry and, as you can see, patented an excellent tank inert gas regulator device.  I have personally bought and installed a lot of his valves and they worked perfectly and flawlessly on many tanks.  Paul heads up our Tank Venting Forum and can probably help you further - if need be.

 Paul Ostand Tank Blanketing Patent.pdf   127.14KB   77 downloads

 Tank Blanketing Guide - Paul Ostand.doc   141KB   77 downloads

 Venting Aboveground Tanks.doc   373.5KB   51 downloads

[breizh]

Julio ,

 

A lot of good stuff in this link , free download :

 

http://www.leser.com...ngineering.html

 

Good luck

 

Breizh

[jcrivasplata]

Julio,

 

For all blanketing regulators, PVRV's and EV's you need to report the pressure/vacuum relief loads including in relevant data sheets and leave the sizing to be done by reputable vendor(s)...

 

I told the same to my client, but he insisted!. The customer is not always right. But let's just keep that between you and me, shall we? 

I really appreciate your time!

Edited by jcrivasplata, 22 April 2016 - 11:31 PM.

[jcrivasplata]

 

Art,

 

Thanks for the very useful documents you attached.

I finally developed a couple of spreadsheets based on API 2000 and a manufacture's software (Pentair PRV²SIZE). I'm not able to upload any file to the forum but you can find these files in this link .

I really appreciate your time.

 

Regards,

 

Julio

[jcrivasplata]

 

Breizh,

 

Thanks for your advise, I developed some spreadsheets by my own based on API 2000, you can check them out in the following link. (Google drive)