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Mark Johnson

Jun 17, 2014
02:06

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Stack heat loss is touched on within the below WNA URL. Curious to know the velocity of escaping emissions. Unlike a traditional wind turbine, wonder what the turbine blade count/pitch etc. would be to optimize rotational speed based upon emission velocity. Imbalance possibilities due to residue accumulations not uniformly distributed across all turbine blades which points to recurring maintenance (perhaps there could be a self-cleaning mechanical solution). Thank you for this interesting approach, Mark http://www.world-nuclear.org/info/current-and-future-generation/cooling-power-plants/

Patrick Mcnulty

Jun 17, 2014
03:23

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Yes Mark I was thinking variable pitch blading would work nice throughout all load ranges of the plant..

Patrick Mcnulty

Jun 17, 2014
03:01

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Perhaps a teflon coated blade would prevent build up and or just spray it with water to shock it and it will break off...

Patrick Mcnulty

Jun 17, 2014
03:35

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Although gas plants may not be an issue there since it burns so much cleaner..

Patrick Mcnulty

Jun 17, 2014
03:42

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Also many of the plants have two stacks so you can have two exhausts hitting one turbine keeping it balanced..

Tim Elder

Jun 17, 2014
09:35

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Sounds better to me to put the turbine/windmill just inside the top of the stack with a vertical axis. Any extraction of energy from the flow of gasses will be seen as a restriction to that flow; how will this affect the plant.

Patrick Mcnulty

Jun 17, 2014
10:08

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Thanks Tim your right anywhere inside would create back pressure that's why I have it outside to eliminate that..

Mark Johnson

Jun 17, 2014
10:28

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CycloneBuster - Excellent "What If" scenarios. The turbine at the top of the stack makes sense, but the "restrictive exhaust" back pressures (caused by turbine blade air flow resistance) should be quantified through prototype testing. Seems a confluence of (let us say) 5 turbine blades with increasing blade pitch (low to high) in the stack makes sense. We need an F-35 fighter aircraft engineer! VTOL fighter - Vectored Thrust.

Mark Johnson

Jun 17, 2014
10:51

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Teflon coating on blades is a winner. Disperses residue mass. Great idea. Mark

Mark Johnson

Jun 17, 2014
10:35

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Your ideas/knowledge are aligned with "Clean Coal" benefits - why aren't we considering Clean Coal too? America has over 500 years supply of coal. WV residents will rejoice!!

Tim Elder

Jun 17, 2014
10:50

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Also many of the plants have two stacks so you can have two exhausts hitting one turbine keeping it balanced.. I assume this would be the two stack flows hitting opposite sides of the blades. What do the blades do when they are between the stacks? Are they feathered or what?

Mark Johnson

Jun 18, 2014
09:49

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Combining two stacks seems to me to channel just one airflow across the turbine blades. Feathering would only apply if there is a high air flow to "clean" the main burn box below.....much like Navy ships "blow tubes" to extract and remove carbon residue. Don't get me wrong, I know the damaging effects of coal, but DoE was seriously evaluating the routine use of "clean coal" technologies to make coal use viable. This went up to about 2011. Keep Charging!

Patrick Mcnulty

Jun 18, 2014
09:11

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Perhaps one like this centered above the stack would keep it balanced.. http://assets.inhabitat.com/wp-content/blogs.dir/1/files/2011/11/Ecowhisper-wind-turbine-3.jpg

Tim Elder

Jun 18, 2014
04:53

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In the proposal you say that it will save "7% of 13%." That is .9% = .009. This doesn't seem like much.

Patrick Mcnulty

Jun 18, 2014
05:29

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Good question Tim I have to back and say 7% of the total 100% fuel burned now. Thanks..

Mark Johnson

Jun 18, 2014
09:38

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Do we have a total stack count - throughout the USA? Curious.

Patrick Mcnulty

Jun 19, 2014
03:07

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I haven't clue on that one Mark but I am sure it's in the 1,000's or perhaps 10,000's... :)

Saravanan Dhalavoi Pandian

Jun 19, 2014
04:23

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Hi, Nice concept and innovative thinking. However have you considered the following: 1. Introducing a turbine to recover flue gas velocity (14 to 20 m/s) in a stack height of say 200m will create back pressure for the Induced Draft (ID) Fan of the boiler and will increase the ID fan power consumption. I guess this could be equivalent to the power generated from the turbine that would be introduced in the stack. 2. Could you expand how you could recover the 13% heat loss from the stack flue gas. The flue gas temperature for typical coal based boilers used for power generation would be already at low temperature at 150oC. Many thanks.

Patrick Mcnulty

Jun 19, 2014
05:56

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Since the turbine is above the stack the back pressure would not be as great as if it were in the stack. The rising heat would also help move the turbine as well as the velocity..

Mark Johnson

Jun 19, 2014
05:50

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Hello Saravanan. You seem very knowledgeable per #1 statement above. To perhaps help answer #2, I found a link which I think you'll find insightful. Let us know what you think. Thank you, Mark https://www.carbontrust.com/resources/guides/energy-efficiency/heat-recovery When the above URL opens, look down the page for "Further Guidance" and click the top link "Heat Recovery" which opens an excellent .pdf guide with great content and images.

Chad Knutsen

Jun 19, 2014
06:03

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Consider utilizing the principles of Redirection, rather than Resistance. 1.618... can help to create spirals that will help redirect and intensify the velocity of the escaping gasses/vapors into your turbine. Just an idea. Or perhaps, the heat inside stacks could be used to heat water contained in pipes inside them to generate steam that was then redirected into a turbine and water recatchment/recycling system. another idea. Your general concept of taking advantage of all that wasted heat and velocity is fantastic! There could be many ways indeed to take advantage of that energy!

Tim Elder

Jun 19, 2014
09:47

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Since the turbine is above the stack the back pressure would not be as great as if it were in the stack. The rising heat would also help move the turbine as well as the velocity.. I wondered about this statement when you explained it before. Yes, there will be less back pressure because there will be some "leakage" between the stack and the turbine; but it will not be zero. You are extracting energy from the plume; the energy to turn the turbine to generate electricity will result in increased back pressure (and more leakage!) This increased back pressure will reduce the velocity of gasses in the stack (which reduces the kinetic energy of those stack gasses.)

Patrick Mcnulty

Jun 20, 2014
09:12

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What is the molar mass of those stack gasses compared to the air we breath? Sounds like we can get more bang for our buck.. As far as back pressure a few more watts on the ID fans may well be worth 7 to 10 mega watts from the turbine generator.When we base load the units we are far from red lined anyways.

Climate Colab

Aug 13, 2014
04:20

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While novel, we believe that this idea can be flushed out in a more detailed and comprehensive proposal, which includes pricing, details on emissions averted, and scalability. This may be a good concept to use as a launching point for next year's contest. As you've submitted many proposals, we've elected to advance the proposals of yours that are the most developed.