Want to get rid of steam turbine pump.?? 1

[Vaione]

hey guys how are u all?

Hey we have steam turbine pump at cooling tower and now we wanna switch to electric motor driven pump. we are plannin to put 75 HP motor and wanna hook up our motor to generator, but now question arise, our generator capasity is 55 KW and when i counted Kw for 75 HP motor it comes to around 66. now suggest me wat are the possible way i have.?? how can i get rid of steam turbine pump and use electric motor driven pump???

 

[MartinSr00]

It looks like your short generator capacity. You need to either get some more generating capacity from somewhere, (maybe even from an electric utility) or find a way to reduce the pump energy requirements.

 

[steamdog]

Why not use the steam you are not using in the pump to run a turbine driven generator??

 

[Vaione]

Its a spare one. i dont know why my boss wanted to get rid of steam turbine. but he has idea about electric motor driven pump and want to hook up generator so when electricity gonna down we can esialy run our pump using generator.

 

[waross]

You should be looking at a larger generator. I would use 175 KVA to 225 KVA standby rated to start that motor.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Vaione]

ok waross.. thanks for suggesting this, but still any other way around that we can change pumping rate or somthin??

 

[waross]

Well you could direct connect the motor to a dedicated generator.
You could probably drive a 50 Hp or 60 Hp motor with a direct connection.
There are a few issues.
>The motor should be connected to the generator before the generator is started, and if the motor is stopped the generator should be stopped before restarting the generator.
>The motor control and protection must be arranged for a ramping voltage start.
> A Variable Frequency Drive is a good choice for starting motors on a weak source, EXCEPT for generators. Many VFDs send a lot of harmonics back to the source and generators and particularly the Automatic Voltage Regulators on generators don't like harmonics.
Recommended generator sizes for motor starting.
Direct On Line motor starting with other loads. Base loads plus 3 KVA per Hp. see note #1
Direct On Line motor starting with no other loads or other loads able to accept voltage dips. Base load plus 2.5 KVA per Hp. see note #1
VFD motor control. Base load plus 2 KVA per Hp.
Generator starting with direct connected motor. 1.25 to 1.5 KVA per Hp.
If there is more than one motor, all except the largest motor may be considered as part of the base load.
When the boiler is up to pressure, use the steam turbine. For black starts use a high volume, lower pressure pump to charge the boiler. Possibly add a second small high pressure pump to maintain the boiler level until there is enough pressure to run the steam turbine pump.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[TBP]

The electrical equipment to drive this little pump is snowballing pretty fast. What kind of payback are you looking at for this adventure?

 

[waross]

What equipment do you have on hand now? You may be able to kludge something together that will do the job.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

"The electrical equipment to drive this little pump is snowballing pretty fast. What kind of payback are you looking at for this adventure?"

The generator isn't big enough. Buy a bigger generator.


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If we learn from our mistakes I'm getting a great education!

 

[TBP]

ScottyUK - How does factoring-in the cost of buying & installing a bigger generator help with the payback?

 

[ScottyUK]

Well, it injects a dose of reality into what is fast becoming a ridiculous thread. Reality is always a good starting point in solving problems. A diesel set of that sort of size from one of the better manufacturers is going to work out in the £35k area, at least on the UK pricing structure.


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If we learn from our mistakes I'm getting a great education!

 

[waross]

Well if the generator and pump are on site, there may be a solution.
The controls must be modified to run fro an external source, possibly batteries or batteries and an invertor.
The pump may be permanently connected to the generator. If the load o the pump exceeds the power of the diesel, the diesel will slow until enough load is shed to maintain equilibrium. The generator will be unsuitable for other loads.
The maximum current must be checked carefully. The dead rack may have to be adjusted on the diesel to avoid overcurrent in the generator. I would not design such a system from scratch for such a small application, but if the equipment was to hand I would invest the time to give it a try. System performance will be similar to a VFD with a power limit set at less than 100% of the motor rating. The speed torque curve of a centrifugal pump should make this doable. As the boiler pressure rises, the load on the pump motor will drop with may pump curves.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rmw]

Yes, Scotty, this one is a strange one. Obviously the OP has some electricity at site because he/she was able to get on the Internet and post the OP. Now, how it is that he/she can pipe steam out to this cooling tower but can't get enough electricity out there to run this pump? I think we need to know more about the plant, its layout and the overall application before we all go off half cocked and propose all kinds of pie in the sky. Is all this steam and whatever the cooling water is used for generated without electricity as well?

rmw

 

[ScottyUK]

I have so far resisted the temptation to suggest removing the alternator from the genny and direct coupling the engine to the pump. The engine will have a better chance on its own than using the undersized generator as an intermediary.


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If we learn from our mistakes I'm getting a great education!

 

[Vaione]

hey guys thanks for all repiles. I was out of town for last 2 days.We have generator and Pump both at plant. now we looked into wiring and other consideration. we can hook up our pump with our generator. But we need to put out 15000 GPM water. Now only 75 hp motor we help woth this and lower Hp motor mgiht not gonna do that. and KW for 75 Hp is more than our generator capacity. We have total two Pump one is steam and one is electric drive now we want to put one or both electric drive pump. previously when one was working one was in spare.right now we have only one pump and that is steam turbine. we sent our other pump for repair. once we gonna get it we are going to put that pump and hook up generator with that. but the porblem which i told u guys is goign to be there. can i run both pump and share load or somthin?

 

[TBP]

Will your piping system handle 15,000 GPM?

I'm sure that there are factors of which I'm unaware, but from the info - as I understand it - Rube Goldberg would be proud.

 

[Vaione]

hey man sorry i miss printed this its not 15000 it is 1500..

 

[ScottyUK]

Hey, just go ahead and try it. I think you're going to anyway. Video it and if anything exciting happens, like the alternator catching fire, then put it on You-Tube.


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If we learn from our mistakes I'm getting a great education!

 

[waross]

Good call on direct driving the pump with the diesel, Scotty.

Bill
--------------------
"Why not the best?"
Jimmy Carter