Home › Forums › Coking › Maintenance › Pumps, Valves, Rotary Joints, Cranes › Pumps › Heater Charge Pumps Reliability
This topic contains 10 replies, has 6 voices, and was last updated by Paul R Orlowski 7 years, 4 months ago.
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February 2, 2007 at 8:22 am #4059
AnonymousWhat 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%?
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February 2, 2007 at 8:51 am #7467
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?
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February 2, 2007 at 9:55 am #7466
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.
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February 5, 2007 at 5:25 am #7462
AnonymousAlso, 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 -
February 5, 2007 at 5:29 am #7461
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 -
February 6, 2007 at 11:02 am #7458
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 -
February 8, 2007 at 2:54 am #7454
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 -
January 21, 2008 at 8:46 am #7091
AnonymousGood Morning All,
Does anybody have a 4 stage (or more) heater charge pump ?
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January 6, 2011 at 7:58 am #5349
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 -
April 12, 2014 at 4:59 am #12663
AnonymousWe 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?
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October 5, 2015 at 11:38 pm #18840
just doing forum maintenance
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