Cooling Water Supply Pump Challenge! 1

[francis_mechanical]

I was sizing a pump that will supply cooling water to 26 diesel engines.

The capacity of the pump is near 2600 GPM

(Im new in sizing pumps)

I was searching the internet to get a physical feel on how big this pump is. And 2600 GPM pumps are quite big (for me)

The estimated size of the discharge is 12in! Maybe this figures are realistic but I don't want pump discharge this big.

I'm planning to install 2 set of pumps instead of one to reduce the size of the pump. so 1 set of pumps for 13 engines, and other set of pumps to the remaining 13 engines.

Is this a good design?

 

[georgeverghese]

As hinted at, check if you need to have one dedicated diesel engine driven CW pump ( or connected to external power supply) for blackstart ops. And the UPS with battery backup for 110V control power for blackstart. May be you can manage without blackstart critical power supply to the air cooler - here the blackstart heat rejection load should be enabled without the fans running (ie. on pure natural convection mode).
A crude orifice plate type FE with dp guage may be all that is required to set the butterfly valves on each supply line.
Check if temp control on air cooler exit is required. Options are to put some fans on VFD or run an air cooler temp bypass line.
N2 blanketing of the CW expansion drum would be a good idea for corrosion management. CI injection lines required for oxygen scavenger / biocide. Use demin or low chloride RO water for topping up at the expansion drum.
Watch out for end of curve runout when the standby pump starts up - this will affect pump motor hp.

 

[LittleInch]

francis - too many variables to make even a guess.

Many/most engines contain thermostatic valves in the engine which shut off cooling water supply until the engine reaches operating temp (90C), then controls the water to maintain that as a minimum temperature leaving the engine.

Some of the variables include:
How many engines?
How long does it take each to reach op temp (lots of metal involved as well as water)
How much volume in the loop?
What flow velocity?
Is the cooling system turned on?

My estimate is somewhere between 10 minutes and 30 minutes.

LI


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

One issue not discussed so far is cooling water thru' the engines. Do you intend regulating and controlling flow via the supply system you are considering to effect cooling, or supplying water to the engines at low pressure and relying on the engine water pumps and thermostats to control and regulating cooling as required ?
I think you have a lot of decisions to make as to the operating conditions before worrying about pump/'s, pipeline sizes etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[LittleInch]

You might find that the engines cooling system is actually self contained and what you're doing is sending water through a heat exchanger - what the article here

http://www.onsitepoweradvisor.com/2011/09/25/engine-cooling-systems/

calls "a dual-loop remote radiator cooling package"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

Have you looked at gravity feed to the engines with a pump return system to a cooling tower.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[MikeHalloran]

I'd like to post the diagram here but I don't want the topic to be diverted to other issues that people might see on the diagram. For now, is for the supply system of the cooling water, its sizing and arrangement.

Yeah, about that.

By being coy about the overall system architecture, you have caused a bunch of very smart people to waste their very valuable time chasing rainbows of conjecture.

Go help yourself.


Mike Halloran
Pembroke Pines, FL, USA

 

[georgeverghese]

The country of origin acronym for the OP is too abbreviated in many cases to tell where the OP is from : Can we get the folks running this website to add on a few more letters to reduce guessing?

 

[Artisi]

Knowing what / where the OP originates from won't make much difference, time wasters,wheel-spinners and users will still waste people's time with insufficient half-arsed information.




It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[francis_mechanical]

Hi! I'll be posting the whole system, PID and Layout here, so that everyone will have fun. SOON, but for now.

This power plant anyway will be very helpful to my community since we have a massive power shortage here.

The plant will be run by hydrogen internal combustion engines.

@curtis2004
"So you probably will have 5 psi pressure drop across each engine"

To be honest, as for now I can't have the manufacturer data for the estimated cooling water pressure drop. I now have multiple sources in my hand, but I still want to know is this a rule of thumb value? the 5 psi? Thanks.

@georgeverghese
"blackstart"

I guess this will not be a problem coz we will be having an external transmission network for the initial power supply.

The question for this thread is whether using multiple circuit for a cooling system is a good engineering design, and it seems that this is already answered. So thanks for that.

The thread also generated multiple useful ideas. Those are bonus, especially curtis2004 & littleinch!

PS, "I can't, for now,. maybe a couple of weeks from now due to contract and papers issues. Anyway, we are proceeding with the design." - This is my answer If ever you ask why I dont have data and keep on asking for suggestion here :-D

 

[lilliput1]

To increase efficiency you should incorporate heat recovery instead of just rejecting it to atmosphere. You can only get about 35% efficiency in the conversion to electricity. Try to recover 45% more. Consider domestic hot water heating, reheat water heating or for use by absorption chillers for cooling.