1 reply to this topic

[simadri]

Hi All,

There is an existing facility with a liquid sulphur storage tank transferring liquid sulphur to destination by one duty (and one standby) centrifugal pump.  Please find the attached sketch for the schematic diagram.

 

Pump Capacity: 120 m3/h

Suction & Discharge line size: 200 NB

Liquid Sulphur Density: 1800 kg/m3

Viscosity: 10 CP

 

In the existing facility, the pressure drop per  is about 0.13 bar/100 m. Liquid velocity is 1.13 m/s.

 

Now, we need to run both the pumps simultaneously. Combined capacity of both the pumps is 240 m3/h. This will cause 2.26 m/s of liquid velocity with around 0.5 bar/100 m pressure drop. Both the velocity and pressure drop are considered as high for pump suction line. 

 

My query is both the pumps will pump 240 m3/h of liquid sulphur causing possible vibration/ cavitation or the system curve will adjust automatically resulting into lower flow to destination.

Attached Files

•  Liquid sulphur transfer.pdf   40.47KB   22 downloads

[Saml]

"Both the velocity and pressure drop are considered as high for pump suction line"

You already have the answer. 

If you checked that there is not enough NPSH or there are other issue that prevents that velocity in suction, then you cannot pump.

 

"system curve will adjust automatically"

The system  will operate at the point where the parallel pumps curve and system curve meet. The usual thing you adjust to change the system curve is the opening of valves (normally a control valve), unless you have variable speed pumps.