Improving Condensor Vacuum

Ejectors only remove any air. Condensing pressure is determined by condensing temperature, which is controlled by the cooling water temperature. What is the inlet vs outlet water temperature? How fouled or clean is the cooling water system?

bigg is correct...

The thermodynamic limitations of your plant are controlled by the temperature of your heat sink, the ocean.

Condenser pressure is only an indirect method of measuring this temperature. Reducing the vacuum in the condenser will not improve your thermal performance.

Review details of the Rankine cycle:

http://en.wikipedia.org/wiki/Rankine_cycle

Further, without reducing the temperature of the coolant, reducing the vacuum cannot happen!

I suggest that you develop and implement a thermal monitoring and improvement program for your plant. Tracking and accurately monitoring the heat rate is an important job.

It is my understanding that you have an open loop, seawater cooling cycle.... this is the type of cycle that is prone to bio-fouling.

There are usually several measures that can be taken on the cold end of the cycle to reduce backpressure and improve heat rate:

Some cost effective measures to consider are:

- More frequent cleaning of condenser tubes

- Automatic cleaning devices for condenser tubes. (taprogee and others)

- Extension of the cooling water intake to draw in (deeper)colder water during the summer season.

http://www.lehigh.edu/~inenr/leu/leu_61.pdf

http://www.t.concosystems.com/sites/default/files/userfiles/files/techical-papers/economic-effects-condenser-backpressure-heat-rate-condensate-subcooling-and-feedwater-dissolved-oxyg.pdf

Is there a set of published Steam Tables to hand at that location? Like "Thermodynamic properties of fluids" by Mayhew & Rogers?

If there is, then the only thing that is missing is an Engineer that knows how to use them.

Yes it is sure that heat sink should be at lower as possible.

Is some one using any method to bring down cooling water temperature.

or any method to improve more workdone in condensor

Turbines are notoriously sensitive to rising cooling water temperatures. I wonder if it would be possible to mechanically cool the seawater cooling water a few degrees using a high COP refrigerant like carbon dioxide at a low compression ratio. There would be a good chance that the energy consumed by this cooling cycle would be less than the energy output loss experienced at the turbine due to a reduced vacuum brought about by a high cooling water temperature. When I get a bit more time I may have a look at this. A simpler method may be to allow the cooling water to be exposed to a high vacuum between the intake and the cooling water circulating pump. Warm water with a vapour pressure higher than the vacuum would flash off, thus reducing the water temperature. The very low pressure vapour would be condensed by a high COP refrigeration process which would be seawater cooled.

With best wishes and kind regards

Yours sincerely

Klaas Visser.

What is your boiler feed-water temperature and rate? If it's temperature is substantially less than (very doubtful) seawater and the rate is encouraging, then a heat exchange between them may be studied...

If you are using an open loop, use a closed loop and natural draft cooling towe or induced draft cooling tower for cooling of the cooling water going to condenser which will improve condenser vacuum.

Improve Condenser Performance

My engineering college project was "performance improvement of condenser by optimisation of cooling tower performance and online condenser tube cleaning system" which was conducted at a 1400 MW lignite powered thermal power station.Unfortunately I don't know, where I kept that project report

If it works in winter, then there is no reason to replace it.And you can rectify this problem by using geothermal heatexchanger which will never cost you a lot and can give you stable fluid (water temperature). The refrigeration is not economical and that will raise the production cost.

A good sounding answer, but my brother, the largest geothermal cooling installation I am aware of is not in Dubai, but in Iowa at a University, and there are literally over one thousand drill holes, even with that it does not exceed 6000 tons. For a 300 MW_e thermal plant operating say at 10,000 BTU/kWh, the efficiency is precisely 3412.14/10000= 34.1%. 300 MW output is presumed here, so the thermal power is 879.25 MW_th , thusly we subtract the output to find the waste heat at 579.25 MW_th.

That is the refrigeration equivalent of 1,976,483,041 BTU/hr = 164,707 tons in refrigeration units (12,000 BTU/hr is 1 ton). Therefore your suggestion would be project rivaling the building of the pyramids in immensity, but nevertheless effective.

I concur with Mr. MJ Cronin who suggested to move out to the deep with the intake, even use an undersea tunnel similar to the one in Melbourne, Australia that will be intake for desalination plant there. They are using low velocity intakes to reduce entrapment of marine life.

Beyond lowering the cooling water intake temperature, they plant operators should perform due diligence to prove to themselves nothing is fouled with debris, mussels, fish, etc. And on a unit this size, they really could help themselves by installing a system to monitor temperature of various points within the tube bundles to make sure they are getting no air pockets. Also make sure air ingress sources are investigated and eliminated. I expect they will find nothing other than seawater temperature in the shallows goes up.

I agree with the comments of Mr. Stewart. Geothermal cooling of circulating water is not practical.

As it has always been, the Rankine cycle is a disappointment.

If economical generation of electricity is your goal, best go for the ultimate combination.... the gas fired combined cycle plant..!

What keeps vacuum is the condensation of the spent steam in the condensor. The lower the temperature of the cooling water the higher the vacuum.

The function of the ejector is to remove the noncondensibles that come together with the steam. As long as the existing ejectors are removing all incoming noncondensibles they are doing their duty and there is no improvement in trying to add ejector capacity. Unless you have leaks in the low pressure section of your turbine condenser, adding ejector capacity won't help. The added capacity will start removing steam but never in the amount that will make a difference in the vacuum. And if that would be possible, that would cost you a lot of ejector steam, much more steam than that you are loosing in efficiency due to higher condenser temperature.

Increase your cooling water circulation and/or clean your condeser tubes inside and out to improve your vacuum. That will surely do the job.

he is looking to drop 2 or 3C to reach the desired temperature and that can be solved by getting the water from more depth and by using the geothermal heat sink the internal corrosion removal of the circulation tubes and the heat sink will also help to obtain the best efficiency.just need to monitor the the the water temp difference in summer and winter.

No.2 -he has to arrange the automatic flow booster which will be activated at temperature rise so more flow efficient cooling.

Yes, and pay the auxillary load penalty for extra pumping, but we don't live a free-lunch kind of a world, now do we?

What about using waste stack heat to drive some ammonia-water absorption cycle chillers, very little auxillary cost, and the newest generation of these has COP of >0.9, compared to the old ones at 0.4. OR someone could actually for once try to scale up the Einstein-Svillard (sp?), ternary absorbtion chiller (ammonia-water-isobutane, as I recall. The ternary chiller they made way back when had COP of >1 I think.