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Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Sir,

Maybe you can check out the following aspects to confirm, hope it can help you

1.Exclude the physical and chemical properties of the process medium changes
2. No abnormal operation when starting the pump artificially
3. The motor is connected to the pump only by coupling
4. No abnormalities at all seals
5. No abnormality in motor exclusion
6. Mechanical internal parts are in accordance with the design requirements

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

I am not familiar with naphtha but a few other random thoughts.

With SG increase, you are 1.11 times more BHP to start.

Pump clearances can cause that but you say they have been checked and are correct.

Assume pump turns freely by hand when down and empty.

Check system for any recirculation valves open or leaking by which is not measured flow in system.  Is the flow you list from a flowmeter or from curve or calculation?

Is viscosity in range for design?  Has it changed?

Is issue high power or high amperage?
What is motor voltage?  If line voltage is lower, amps may be higher for same BHP.

Can you check system pressure compared to original design?  Does it match up with your flowrate or motor load?

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Thank You Mr Randy for sharing your feedback.

Yes, we identified that the increase in density is one of the reasons of motor overload. operating liquid density from 646 Kg/cubic m to 720 Kg/Cubic m which corresponds to a significant increase of 11.5%

Recirculation valve isn't passing.

We haven't checked viscosity part

Issue is motor overload trip on FLC (problem is current consumption. Motor is drawing more current even when pump is operated well below rated point. Please refer attached curves.). Current operating point is 96 m3/hr

I am not familiar with naphtha but a few other random thoughts.

With SG increase, you are 1.11 times more BHP to start.

Pump clearances can cause that but you say they have been checked and are correct.

Assume pump turns freely by hand when down and empty.

Check system for any recirculation valves open or leaking by which is not measured flow in system.  Is the flow you list from a flowmeter or from curve or calculation?

Is viscosity in range for design?  Has it changed?

Is issue high power or high amperage?
What is motor voltage?  If line voltage is lower, amps may be higher for same BHP.

Can you check system pressure compared to original design?  Does it match up with your flowrate or motor load?

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Hi Vaibhav,

Please take under consideration how steep is the efficiency curve of your pump. At reduced flow rate the efficiency is dropping hence the power consumption per 1 cubic meter of fluid is increased in relation to Nominal Flow Rate. Another thing is that you run the pump with more dense fluid than rated one - these are two major factor for power increase.

Cheers from Grundfos

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density. 

Hello Sir,

1. Can you check the check valve for any backflow that cause reduced flow rate.

2. Is the strainer is cleaned or the try to replace the strainer?

Greetings Members,

Looking forward for your valuable feedback in resolving a centrifugal pump (API type OH2) high power consumption issue. Service media is naphtha.

Problem Statement: Pump is drawing more power at reduced flow rates. Refer attached pump operating parameters. Current discharge flow rate is 96 m3/hr. However, design flowrate is 124 m3/hr. At 96 m3/hr motor current is reaching FLC.

Findings & Observations:<o:p></o:p>

<o:p> </o:p>

1. Current reported liquid density was checked, and it is averaged to be 720 Kg/cubic m since commissioning.<o:p></o:p>
2. As per the pump performance curve, the pump & motor combination are designed for liquid density of 646 Kg/cubic m .<o:p></o:p>
3. As per the history, the high current is experienced by both the pumps (1 running and 1 stand-by configuration)<o:p></o:p>
4. Motor winding problem is ruled out as the current is balanced in both the motors. <o:p></o:p>
5. As per condition monitoring observation, the motor & the pumps bearing are healthy and its vibrations are within limit.
   6. Pump was overhauled and internal clearances are within design limits,.  <o:p></o:p>

<o:p> </o:p>Members support is requested to identify other potential causes leading to this issue. Please note, operation team informed that there is nothing they can do about the naphtha density.