4 replies to this topic

[Vegeta]

Dears,

 

Attached is a schematic drawing of a loading facility.  We are working to install minimum recycle lines for each pump. My question is that: is the configuration I have in the drawing ( having two header, one for each three pumps) is preferable over having one header for all pump? or vise versa? considering the scenario that this facility have of operating three pumps in one set vs. one pump in the other set and the long 14" discharge headers, the three pumps will have their operating point close to the MCSF on the pump curve and the pump that is on alone on the other set will have its operating point shifted toward the right of the pump curve. This will make the power loading on the pumps that is on alone higher than the three.

Also, what could cause the flow to go down?

 

 

Another question,

 

What is the typical bulk modulus of diesel, gasoline and fuel oil?

 

Regards,

Attached Files

•  Loading Facility.JPG   71.6KB   4 downloads

[ankur2061]

Vegeta,

 

If your six pumps are considered as two sets of 3 pumps and as per the operating philosophy of each set of 3 pumps operating independently with individual discharge headers, then the minimum recycle scheme as shown in the sketch is perfectly OK. Make sure that while specifying the control valves in the minimum safe recycle line, you correctly specify the control valve inlet and outlet pressures including the static head and the line friction loss.

 

For bulk modulus, refer the chart in the link below:

 

http://www.cheresour...pipeline-surge/

 

Regards,

Ankur.

[Vegeta]

ankur,

 

Thank you for your reply.

the system as I said can have one complete set of three pumps running and one on the other set: a total of four running pumps at a time. This is dependent on how many trucks are waiting to be loaded at a time: there may be one, two, three, four, five, or six. when there are five there must be 5 pumps operating as the client specified & this will be 2 vs. 3.

Is there a drawback of having one header for the minimum recycle lines?

 

Regards,

[ankur2061]

Is there a drawback of having one header for the minimum recycle lines?

 

 

Vegeta,

 

Combining individual pump minimum recycle lines into a common header for multiple parallel pumps is an established design practice. The one design aspect that should be given due care is to size the common header considering the maximum flow based on the philosophy of the maximum number of pumps operating simultaneously in a given set of parallel pumps. This should be discussed and frozen with the client to avoid any design issues related to the pipe sizing.

 

BTW, did you find the chart for bulk modulus useful in the link I had provided.

 

Regards,

Ankur

[Vegeta]

Ankur,

Thank you for your reply.
To do a hydraulic calculation, you need the source pressure (the pump discharge pressure at MCSF which can be assumed as it is at its shut off), the line loses, static pressure difference, the destination pressure and the rest available pressure will be for the control valve. In my situation, what will be the destination pressure in the main suction line?

I like the chart of bulk modulus, as it relates it to the density which is normally known!

Regards,