Heater Charge Pumps Reliability

[Anonymous]

What is the latest design in heater charge pumps arrangement? I’d like to know about reliability experience between 2-100% vs 3-50 or 60%?

[Lucibar DavalilloParticipant]

I have seemed cavitations problems with both arrangements, as well as with different designs: barrel type pumps (API BB5) and radial split type (API BB2). Anybody with good experience?

[Ken OsmentParticipant]

We operate two separate upgraders, each utilize radial split pumps, one service is single stage the other two stage. The first upgrader is 2 x 100% the second upgrader is growing from 3 x 50% to 5 x 25%. From experience your optimal arrangement is the 3 x 50% arrangement as you do not lose total production in the event of a trip, and you can reduce capacity by shutting down one pump such as in the case of a furnace pigging or partial outage. Reliability takes an exponential decline as additional units are run in parallel, as pump condition is never matched and weaker units are backed out by stronger units. This can be mitigated by a proper control regime consisting of individual recycle loops, but this is rarely ever done due to the added complexity and initial cost. We are also adding a third upgrader and it looks like it will be using a three stage barrel volute design in either 3 x 50% or 4 x 33% operation. I am still hoping for individual recycle lines. 

[Anonymous]

Also, it depends on turndown of the unit, because this it can be fixed by turndown of the furnace (generally greater to 60% of its design) ,  As the discharge pressure in that pumps are over 500 psig, the minimum flow for these pumps are over 60%, Thus 2 pumps designed to  the 100% possibly it makes operating under this condition impossible(turndown condition),  unless that you  install a recirculation line (minimum flow; You have to take care in this design, in order to avoid the high vibration on control valve/RO/etc, depending what are you going to install in order to reduce the differential pressure in these system)
 
In the case that you  install 3 pump to 50% you have to review/to assure that when operating, only one pump, it has the capacity to operate to the minimum flow  of a furnace
 
Also having 2 (50%) pumps operating, in case of fault of one  pump is easier to avoid  the shutdown for low flow in the heater, since in some cases a single pump allows to operate to minimum flow of the furnaces (in the case of the unit it has 2 furnaces)
 
Also it is necessary to consider if they will be electrical or of turbine
 
 I beg you pardon for my English

[antonio saura CebrianParticipant]

Also, it depends on turndown of the unit, because this it can be fixed by turndown of the furnace (generally greater to 60% of its design) ,  As the discharge pressure in that pumps are over 500 psig, the minimum flow for these pumps are over 60%, Thus 2 pumps designed to  the 100% possibly it makes operating under this condition impossible(turndown condition),  unless that you  install a recirculation line (minimum flow; You have to take care in this design, in order to avoid the high vibration on control valve/RO/etc, depending what are you going to install in order to reduce the differential pressure in these system)
 
In the case that you  install 3 pump to 50% you have to review/to assure that when operating, only one pump, it has the capacity to operate to the minimum flow  of a furnace
 
Also having 2 (50%) pumps operating, in case of fault of a pump is easier to avoid  the shutdown for low flow in the heater, since in some cases a single pump allows to operate to minimum flow of the furnaces (in the case of the unit it has 2 furnaces)
 
Also it is necessary to consider if they will be electrical or of turbine
 
 
I beg you pardon for my English

[Lucibar DavalilloParticipant]

I agree on 3-60% as more flexible design; how about the arrangement of 2 electric- 1 turbine? 
 
Thanks all for your valuable responses
 
Lucky 

[antonio saura CebrianParticipant]

Lucky, Having a turbine from the operational point of view during starting of the units, is easier the use in order to handle the low flows than a electric pump, we have this configuration in at least 5 units.  That means that always it would have to be the turbine with an electrical one in operation. This is my opinion
Regards

[Anonymous]

Good Morning All,
 
Does anybody have a 4 stage (or more) heater charge pump ?
 
Thanks

[Lucibar DavalilloParticipant]

Has anybody installed minimum flow bypass for any pump arrangement? If so, does it work? It’d take lot of pressure drop and possibly piping vibration issues with potential leaks; no to mention dealing with preventing plugging issues.
 
Any feedback is highly appreciated
Lucky

[Anonymous]

We are having the individual minimum control valves and its bypass arrangement. But we have faced flange leakage in one of the control valve once from last 3 years.

Please check whether your minimum flow bypass line is designed for minimum pump flow or not?

[Paul R OrlowskiKeymaster]

just doing forum maintenance

[Author]

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