Thermal Power Station

Increase the heat.

Burn 20% more fuel.

You need a team of experts to evaluate the existing system and make recommendations that would result in a money vs increased output options, then choose the option that meets your goals....

What more can I say?

JR,

There was a bit of whimsy/sarcasm in my answer, I thought about adding an additional 3-5% to account for the increased losses but then I thought that such an unthinking question required an equally unthinking response.

Alan

btw- overall heat-rate tends to go down as plant size increases; i.e., the efficiency gets incrementally better, not worse.

"There was a bit of whimsy/sarcasm in my answer,..."

I understood that, tried to respond in kind, but I can't get emoticons to work on my ad in this site ...

Build it larger in the first place.

Thanks friends for your feedback. And moreover this increase in output falls within the capacity of the plant which i hadn't mentioned previously. anyhow thanks once again to all of you.

Then the brief answer is "increase the load."

PS: You still haven't 'mentioned' the capacity of the plant.

Add a 20 MW Turbine...

There is no brief, accurate answer to this question.

Many engineering laymen do understand that any machine is designed to slightly exceed their specifications in order to meet these specifications. What few laymen understand is when one exceeds the stated specification there is always a price to pay somewhere. How big of a price usually depends on the length of time that one exceeds the specification. If the time period is measured in seconds or fractions of a second then the price can just be the price of replacing machine protection devices.

What baffles many laymen is that a modest boost in performance can be apparently achieved with little immediate impact. Usually the impact happens in the Mean Time Between Failures (MTBF) across the whole machine in this scenario. An apparently modest boost to 10% above rated performance can easily reduce the MTBF to 1/10 of it's previous value. So a machine expected to last 10 years may now fail in only one year.

Dear Friend.

To achieve something you have to sacrifice something .

In the first place, you can increase the combustion rate of fuel by addition of a turbocharger accompanied with Oxygen gas, to be forced into the furnace. this can increase the heating rate of your power station and inturn efficiency.

But the economics of using the turbo charger and oxygen have to be considered and I feel it will solve your problem.

Dear Mr.ravi bagewadi,

I am afraid that mere additional heat release in the furnace alone is not the solution and it will create problem. The heat released should be transferred by the Boiler Tube Heating Surface, which has got a SPECIFIC HEAT TRANSFER RATE and variation will be marginal and it will not handle 20% more as stated in the original post.

If heat is not transferred by the Heating Surface and absorbed by water, the Furnace Temp. will GO UP, Super Heated Temp. of Steam will shoot up, Heat Loss through Stack Gas will go up etc. Higher Furnace Temp. will lead to Travelling/Dumping Grate problem, Melting of Ash etc.will occur.

Possibility of adding ADDITIONAL HEATING SURFACE, ECONOMISER, SUPER HEATER etc. should be studied by a COMPETENT AUTHORITY.

DHAYANANDHAN.S

use waste heat recovery,economiser etc

That would only increase the efficiency, and not the rating.

Read the text that you would have been given for this assignment - or attend more lectures.

Get a bigger/additional boiler.

Good Luck, Old Salt

Dear Mr.shazhadkhan,

Your question and that is " How we can increase the output power of a thermal power station"

It needs a thorough study, on all front including, Boiler, Steam Line Capacity, Turbine Capability, Alternator Capcity,Electrical System, etc., etc.

The lowest capacity in the system will decide the real capacity, if any, available.

DHAYANANDHAN.S

Looking at your post #15, it appears that the problem is that the plant is performing below design specification. Somewhere in the process there is/are one or more bottlenecks. You should be able to check the rate of fuel burn and combustion air delivery against design, pressure and temperature of the main steam line but beyond the obvious, you need experts in the various disciplines.

Have tried asking the operators? they may have the answers, but, I'm sorry to say, managements often think it is below them to ask for knowledge from the people they supervise.

I think it is more complicate.First of all the overload for a limited duration may be permissible for most of turbines and boilers-the generator is built for overload-usually.I don't think you need overloading except in peak hours.I saw for 2-3 hours even 50% overload.

See[for instance]:

http://www.energy.siemens.com/br/pool/hq/power-generation/power-plants/steam-power-plant-solutions/coal-fired-power-plants/USC-Steam-Turbine-technology.pdf

or Google "Turbine and boiler permissible overload"

Instead of a conventional cooling tower that simply consumes auxilliary power, get yourself a real engineer, and build an AVE (atmospheric vortex engine). This can recover energy from low-grade waste heat (hot water from condensing steam for example, and maybe stack heat), generates a stationary vortex (cyclone) that goes way up in the air, generates a great deal of convection of local air at the ground level, and turns wind turbines attached to the AVE structure. You will still get to cool off the process. If the AVE recovers 20% of the waste heat (which is about 60% of the heat used in the first place), then the power output of the plant just went up 30%. Good math.

Wow James, why don't you just put a turbine in the stack and use the flow of hot air to turn a turbine?? Aw shucks, that would cause a restriction in the stack and increase the back pressure into the boiler which would upset the mass flow rate through the boiler and cause problems with the fuel management/pollution control computers, etc.

Seriously though, if you use hyperbolic cooling towers the only auxiliary power required is to pump the water through it, the shape of the tower creates a totally "free" convective flow of air, something that would be severely curtailed if you placed any restriction (your turbine) at the outlet.

Utility engineers have studied these type of problems for years, and are pretty damned good at getting the most bang for the buck. After all, when you design something to operate 250,000 hours you really do try to reduce your hourly operating costs.

It always angers me to see how much waste heat is produced in a typical plant, but the laws of physics and thermodynamics usually make it uneconomic to go chasing all those low-grade BTUs (but I do like combined cycle plants).

I don't think you should laugh at the AVE idea too much. I agree this is new stuff, and maybe not mature enough to be out there yet, but there are plans (I have seen them) for such a critter to be installed on the cooling side. Since the AVE creates a local vacuum (tornado like vortex), I doubt there will be a performance problem, since I have been aware for a long time "there is no gravity, the earth sucks". That's a joke, son.

If steam turbine back-pressure increased by 0.5" Hg by using this AVE device (I have no idea that it would be this much if at all), steam turbine output would suffer some small percentage, but if you get back +30%, then you have a wild increase possible in plant output, without installing a new unit.

James,

Yes, the AVE is an interesting concept, but no, it has not been proven that the vortex will continue once any restriction is put on the inlet air. All the modeling and testing "prove" what is already known, that convection creates rising air currents, the "twist" here (pun intended) is that instead of smooth laminar flow, a vortex is created.

As I said earlier, hyberbolic cooling towers do the same thing without the vortex. Any restriction at the cooling air inlet reduces the velocity of the air through the tower. Put a fan down there and it will turn, try and take and take power off that fan/turbine and it will slow down as it is loaded up. That restriction will reduce the amount of air passing through the tower and its effect will ripple back through the boiler system. It appears they are accounting for this, that's why they have set their goal at 20% recovery.

But just remember, if they draw off 20% of the cooling flow, then the energy for that 20% gain has to come from somewhere, and that "somewhere" is the fuel that made the water hot in the first place. The forces moving the air do not magically come out of the atmosphere, they come out of the temperature difference in the air column, and that comes from the heat input from the fuel that was burned. There are no free lunches at the Carnot Cycle shop, sorry, dad.

Alan

When waste heat can be used as is then co-generation uses can be beneficial. The classic example is the heater core of an automobile in winter.

Red,

"...The classic example is the heater core of an automobile in winter...", that's simply rejecting the heat in a different place. On the other hand if you were to try and use that heat to drive an ORC (Organic Rankine Cycle) turbine and generate additional power for the batteries in your hybrid, that would be a fine example of co-generation.

Alan

When and if....cogeneration....district heating.... all of these are noteworthy ideas, but it is extremely site specific as to the relevance or potential for success.

AVE - the idea is not to restrict air flow, and the vortex will still operate off 80% of the waste energy not recovered. Hey even if they can only do 10% (way conservative estimate), then the power plant will still gain in production by 15%:

10% of 60% is 6%. 6%/40% = 15%. We can all take a deep breath, and relax, and see if anything comes from it.

BTW - check out RAMGEN's new constant volume cycle gas turbine. (off topic, but a valiant step in making generation more affordable/efficient. Also will run off dilute sources of methane (lean premix, operates near the burn instability point more easily than normal Brayton cycle).

James, It appears that you're well intentioned and familiar with technology, but when you say "...the idea is not to restrict air flow..." I'd like to know how it extracts energy from the air flow. Once you put anything, your hand, you, a fan, in the path of moving air (or any medium for that matter), you have altered the air flow, and if work is extracted from the turning fan, then the air has to give up some energy to do some work overcome the restriction. In the case of the AVE, the "thing" that makes the air move is the change in temperature from the bottom to the top of the vortex, and that change in temperature comes from the fuel source that is feeding it. Unfortunately reducing the air flow makes the temperature of the water returning to the condenser go up which makes the vacuum go down and the output of the turbine goes down as well. I'll check out RAMGEN (I wonder why I like the name) when I have a better internet connection, thanks for the lead. Alan

Still remains to be seen how plant cooling efficiency is affected (good or bad), as a better designed cooling tower may be in the offing for plants that would consider this.

Yes, there is a loss of the potential, but that is what happens to any energy conversion from thermal to mechanical to electrical. Nature of the beast. IF the turbine (steam side) loses 1-2% as output, but the overall plant gains 15-30% total output, how is that a bad thing?

If the RAMGEN thing works out, it might well be moot to be discussing (1) cooling towers at all, or (2) combined cycles, or (3) cogeneration...maybe.