Condensate Extraction Pump Going Horizontal

[StressReversal]

Hello Forum members,

Does anybody have experience with horizontal centrifugal pumps for condensate service in a Combined Cycle Power Plant utilizing an Air Cooled Condenser?

This is really a rare design and I would like to know if someone has experience with it and how it works out.

Thanks for your time.

 

[GHartmann]

I am not understanding your concerns or question.

Horizontal centrifugal pumps have certainly been used in low NPSH condensate pumping applications. The use of vertical turbine pumps for certain "physical" plant arrangements (condensate "hot well" close to ground) does obtain the necessary pump NPSHr somewhat more readily.

 

[LittleInch]

Post an example or a link to an example. By condensate do you mean water? It's commonly used to describe hydrocarbons as well!

Sump pumps and similar are often shaft driven "horizontal" pumps.

Need more details (size and head e.g.)and what your issues are.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[JJPellin]

We do not have a Combined Cycle Power Plant. But, we have a number of large, condensing steam turbines that use air cooled overhead condensers. Of these, only one uses horizontal condensate pumps. These pumps are API, single stage, overhung centrifugal pumps. They work very well and have had good reliability.

Johnny Pellin

 

[StressReversal]

Thank you all for your responses.

GHartmann and LittleInch,
There is no specific issue I am having with any pump. I was just asking if more experienced engineers had experience with "horizontal pumps for condensate service in a Combined Cycle Power Plant utilizing an Air Cooled Condenser". I wanted to know their experience with them and how they are performing, if there are any special design considerations to pay attention to, operational problems, etc.

Thank you JJPellin for sharing that with me. That is exactly what I wanted to know. It's only because it's the first time for me to see horizontal pumps in water condensate service (Power Plants) that I wanted to know the experience others have with this arrangement.

One project I am working on utilizes a Condensate Tank with 11.5 meters height elevation; hence, there is sufficient NPSHa for the pumps to work in a horizontal position rather than vertical, but the surface pressure is vacuum pressure. The pump rated flow/head is around 500 m3/hr / 300 m. Some questions would be:

* Is there a need to have the pumps designed to take Full Vacuum, even though they will always have a column of water maintaining positive pressure?
* Do these pumps have to be API or is that considered overdesign for this service?

 

[GHartmann]

In my opinion there is no need for these pumps to be API design. I believe the ANSI B73.1 should suffice.

However, if every other pump in the facility is API 610, then you may want to have the same style and manufacturer for common spares where possible.

Now for your specific application you will more than likely require a multistage pump to achieve your required head.

I don't know that your pumps need to specified for vacuum, but perhaps some consideration made to the seal design. The ultimate decision should be based on a quick HAZOP of the system (low level, high vacuum at pumps as a result of some system fault) with your project design peers.

 

[JJPellin]

I would not require API pumps for this service. There is nothing in the design that I would change for full vacuum as compared to partial vacuum. The seal would be capable of full vacuum. The case would be capable of full vacuum.

Only two of our condensate pumps are API design. All of the others are vertical turbine pumps that are not API.

Johnny Pellin

 

[LittleInch]

Stress reversal,

I misunderstood what you meant by horizontal pumps - my error. The thing is the pump doesn't know what it is connected to, it just sees fluid at a certain head and flow. The question you really need to ask should be based around the process conditions, i.e. this much NPSHA, temperature, flow, type of fluid..

With 11.5m of head, if indeed this is the case, standard horizontal pumps are very common.

I agree with others, API pumps are probably a bit OTT for this sort of duty but it all goes on the process conditions. Actual design of any condenser set-up, elevation, access will be different and hence different pumps used.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way