Industrial Pump Incident

[Inchtain]

Hello,

We have two vertical pump installed (one is stand-by) at an API Separator to transfer the recovered crude oil back to the production separators, where the suction section is submersed in the oil.

Few days ago, when the operator was ordered to switch off the working pump and start up the other, he noticed some vapors coming from the part below the liquid, just after pressing the ON button. He immediately turned the pump off and reported the situation to HSEQ.

I know that it is much more reasonable if smokes seen at the pump motor. So, can anyone tell the possible causes of such situation, before pulling out the pump for general check and maintenance?

Bearing in mind that the pump was working smooth before this issue.

Technical Date:
Max. crude oil temp: 80 degrees Celsius
Ambient Temperature Range: 0 to 55 degrees Celsius
Pump is certified for sour, corrosive and ATEX environment
Flanged mounting
API seals
Pump max. flowrate: 108 m3/hr
Pump Max. differential Pressure: 24 bar
Pump max fluid temperature: 130 degrees Celcius
Pump min fluid temperature: -12 degrees Celcius
Pump Ambient Temperature range: -40 to +55 Degrees Celcius
Pump Max speed: 310 rpm
Pump approximate dimensions LXWXH: 8.3X1X1.1 meters
Main Connections: Suction 8"/Discharge 8"
Pump Max fluid viscosity: 10000 cP

Thanks,

 

[LittleInch]

Need a sectional drawing of the pump and how far above the inlet was the liquid level.

Max viscosity 10,000 cP??? That's treacle.

Crude at 80C - really? in a separator oil tank?

I'm assuming here that an "API separator" is a gravity oil / water interceptor type or something else?

I can only think there was some sort of vapour backflow, but difficult to guess based on words alone.

 

[goutam_freelance]

Please check whether there is a slug stuck in the pump bowl. This will generate heat and liquid may vaporize.

 

[Inchtain]

Please see the Pump Drawing

Correction of some design data:
Pump Flow Rate: 150 m3/hr
Head 30 meters
RPM: 1465
Single Stage
It is installed at a covered Oily-Water Pit where 20 cm space left from the pump to the base and the liquid covers at least 1.2 meters of the down part of the pump
The pump is designed to handle the sludgy and hot mixure.

Thanks

 

[lucky-guesser]

he noticed some vapors coming from the part below the liquid, just after pressing the ON button.

What is "just after"?

Some sort of blockage could disturb fluid flow and cause something similar.

What comes to my mind as worst case, is if your vapors are from boiling off fluid, but that heat would have to be from a bearing failure at the bottom of the column. Which brings me back to my question, as it will take some time for that bearing to get hot enough to start boiling fluid.

 

[georgeverghese]

Thick sludge in this sump pump pit ? Must have bunged up the intake with no flow while pump is running. Overheated oily sludge. Time to clean out this pit. See if you can raise this pump from 200mm above pit bottom to say 500mm to give you a bit more room to hold semi solid sludge before it gets into the pump suction.
Install FSLL ( or similar) on this pump discharge to trip pump - FE should be tolerant to suspended solids and wax in feed. Or else install an online liquid level profiler or similar in this pit.