[Desmond de Haan]

Hi Joshua,

Can you email me the specific case at: rene.bunskoek@howden.com

I will bring you in contact with my colleague David Kuehl, he is very knowledgable on the Cofimco product.

We at Howden would also like to examine your case and see if we could assist.

Looking forward to your reply.

Rene Bunskoek

[Desmond de Haan]

Causing a turine trip by running your plant too close to tubine backpressure trip levels was referred to as joining the ‘ 100.000 dollar turnine trip club’ at the powergen keynote session lat year
source unknoen, but it was funny.

I am sure that with all of the operators active on this forum there will be a wealth of stories to share, but am curious who is able and willing to share and let others learn from their learning curves.

[Desmond de Haan]

Dan,

Congrats on working through the document, that must have taken some time.

As Celcius and Kelvin have the same sclae, only an offset the delta Temp is the same in C as in K

FYI: Celcius 0 is fres water freezing
while Kelvion 0 is absolute zero degress (273 degrees offset)

[Desmond de Haan]

Dan,
Your personal details are not visible on your profile. Can you please send me an E-mail at Desmond.dehaan <at> Howden.com?

[Desmond de Haan]

The study carried out by John Maulbetsch for the DOE at Caithness touched this subject while searching for parameters.
If memory serves, there was not clear cut parameter or set of parameters that could be used to measure ACC performance as the ACC performance is dependant on a number of variables varying from anything from for for example, surface pollution of the bundles, temperatures, wind, air leakage between cells and from cells to the environment, excessive cooling cooling the condensate too much deceasing the HRSG efficiency etc…
As John put significant effort into this I would advise reaching out to him for advice.
My impression is that there is too much happening in the ACC to have a magic gauge showing efficiency per se, but a balanced verdict must be made based on several parameters

[Desmond de Haan]

Makoi,

Key is to understand how much cooling capacity increase you are looking for.
Are you trying to improve peak performance on hot and windy days only, or do you need to increase your performance in all situations?
Spray systems were recently discussed in a CTI paper (TP18-02 Efficient Water Use to Boost the Air-Cooled Condenser Performance) a very good document to understand the concepts better. Downloads available here:
CTI Thermal Performace papers

You can also increase performance by improving the air flow through the ACC by mitigating wind influences to increase uniformity, cleaning your bundles and of course optimizing your fan system.

Spray systems, especially aftermarket, should be used sparingly as the ACC was probably not designed for high humidity or even wet conditions inside the ACC.
A hybrid cooling system with cooling towers to address peak cooling loads such as at Commanche can have dramatic performance effects, but are of a different investment level than the above options.

[Desmond de Haan]

The above comments about cleaning fins, adding water mist to the air and considering wind screens are all very valid points.

Is your ACC a flat horizontal or a hexacoil system?

You state that your fans are maxed out.
I assume that you mean these are at maximum pitch and/or the amperage draw from the motors is maxed out.
Both of these do not neccesary mean that the aerodynamic performance is maximized.

I would suggest to have the fan performance valuated by having the aerodynmaic performance measured, with clean bundles is best. There may very well be the potential to increase th air flow in the ACC with minimal technical impact and low investment.

[Desmond de Haan]

Marko:
Contamination of the heat transfer surface can indeed influence the efficiency of the system, I assume by the fact you are asking you have doubts about the cleanliness of the system.

Also external factors such as ambient air temperature and wind can influence ACC performance. Warmer air will of course cool less, due to lower temperature differential and lower density. Also wind draws extra load on the fans decreasing static pressure output of the fans into the ACC.

You could consider having your bundles cleaned as this is typically good practice, I know many sights prefer the spring for this to be ready for hot summer weather, also it could be a good idea to have your fan peformance evaluated to see if your ACC is receiving sufficient air flow, or if more air flow is required to meet this new cooling capacity requirement.

Please feel free to send me a PM (desmond_DOT_dehaan@Howden_DOT_com) if you need any local references that we may be able to provide assistance for you.

[Desmond de Haan]

This report may also be interesting for you:

http://www.energy.ca.gov/2016publications/CEC-500-2016-047/

I have some contacts at Caithness if you are interested.
Out of respect of privacy: please send me a PM if you are interested.

[Desmond de Haan]

There is no rule for even or uneven number of blades and there are opinions favoring both options as some say an even number passes the bridge simultaneously and others say an uneven number cause a rocking motion.

Vibration trips indicate something much more intense than a fan passing the bridge IMHO. I would first inspect the blade pitch of the blades my notiong if all blades pass the same point on the fan casing when the fan is spinning very slowly.

Some fans have a tracking adjustment that bring an extra variable to the equation, just to be clear, despite the fact I am mentioning this does not mean that Howden fans require tracking adjustment.

If this does help, a vibrational analysis would seem in order to troubleshoot the issue.

[Desmond de Haan]

What has the manufacturer given as feedback regarding the cause of the failure?

I would be happy to offer our assistance in troubleshooting your issue.

Due dilligence is appropraite for severe failures only three yeard into operation. I am sure the gearbox manufacturer would be interested in helping to identify the root cause.

[Desmond de Haan]

I have sent you a private E-mail and look forward to your response.

[Desmond de Haan]

I know there are dedicated anti-rotational devices available for smaller units, ie ACHE’s. I do not believe there are devices or solution specifically designed for ACC’s.

[Desmond de Haan]

Shameer,
please send me a private message at desmond-dot-dehaan@howden.com

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