combined cycle , turbine 3

[rabeh]

hello i m student in an internship
i am demanded from my company to study scientifacly and financialy the idea of adding a steam turbine to a gaz turbine to produce more electricity ( combined cycle) and increase performance of the powerplant
whats the steps that i should do ?
thank you very much

 

[farale]

Steam turbines are not available in every requested size. Please estimate suitable rating of the steam turbine by dividing the gas turbine MW by 2. Then find a similar rating on GE products.
Meanwhile study about HRSG.
In addition to the steam turbine and the HRSG, you need an alternator and probably a unit transformer.

 

[crshears]

In my opinion, your company is being quite unfair to you by asking an intern to do a consultant's job; not only would your career path development and knowledge be greatly enhanced if you had the opportunity to work under a fully competent, experienced and qualified person in properly assessing this scenario, but your company would also have a justifiably trustworthy report in hand to use in evaluating any final decision to proceed.

Remember that we all start out ignorant; I know that I certainly did!

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[rabeh]

i want to know how to calculate the thermal power from the exhaust gases of the gas turbine
after doing biblio resaerch i found that it could be calculated by this formula ( W=m*Cp*T ) m=exhaust flow ; Cp=calorific value ; T=temperature of exhaust gases
is this true ?

 

[BrianPetersen]

Of course, the heat rate of the exhaust gas is straightforward to calculate with that formula. But life is not that simple.

The boiler for the bottoming Rankine cycle won't be 100% efficient - probably far from it.

Whatever you use to turn the heat into power, will have a thermal efficiency of some sort. If the original designer of the gas turbine did a good job, then there won't be much left for the bottoming Rankine cycle to work with, so this could possibly be rather low. The Rankine cycle will have a thermal efficiency that is dependent on the hot-side and cold-side conditions and on the efficiency of the turbine itself and the generating equipment. The thermodynamics textbooks plus literature from equipment suppliers will allow you to estimate what the operating conditions of the Rankine cycle will be, and thus its maximum efficiency. (The real efficiency will probably be lower!)

You will need someplace to reject the low-grade heat from the condenser of the Rankine cycle. Sometimes this is easy ... sometimes it isn't. It is probably associated with a power demand for operating pumps and fans, and watch out for environmental side effects. If you affect the local fish hatchery, look out. If you spread fog over a major motorway next door and there is a major collision with the finger pointed in your direction for producing that fog ... look out. It HAS happened.

You were asked to study the finances. Make sure you consider ALL of the costs and side effects that you possibly can think of, and be aware that there are probably going to be things that you haven't thought of.

 

[crshears]

Agreed, BP, hence my recommendation that such an analysis be undertaken by a competent, qualified and experienced consultant. I was also concerned the OP could be opening a door to a world of hurt; say work product is used, something somewhere goes wrong, and the OP gets named in a lawsuit...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[rabeh]

thank you mister brian peterson for advices
i have all data on the gas turbine , so i take ehaust data of gas turbine and i consider it as an input for the steam turbine that going to be installed then i calculate thermal power with that formula and i search on internet PDFs of companies that shows how much they can produce electricity from this thermal power , efficiency , how much it cost ...and i give that to my company and they make the decision
according to you :
am i doing the right thing ?
am i supposed to know all the small details of the components (because i think its the job of the company whose going to install the steam turbine so the technics that will be used and the characteristics of the components it not really my job) ?
i think my real role here is to find companies and i find how much it cost , how much i can produce electricity ... am i right ?
thanks for your opinion

 

[BrianPetersen]

Only you can know the scope of the project to which you were assigned. The rest of us missed that meeting.

 

[rabeh]

i ve found difficulty finding a website or platform which i can found a PDFs or documents on companies that present information , data (tables,figure...) about installing steam turbines , efficiencies , financial details

if any one know a website or something it will be very helpful for me

thank you

 

[Sazirul]

Why don't you ask your company to provide you the necessary documents that you need. Please let me know how you solve this problem?
Thanks

Wilcox Boiler | LED | Fuse Properties

 

[waross]

Find a company that supplies and installs steam turbines and HRSGs. They will be able to give you all the information that you need.
That company can probably recommend reading and websites on the issue.
You should have a load profile of your gas turbines. As the load on the gas turbines is reduced, the steam output will also be reduced.
If you do your calculations based on 100% output from the gas turbines and then the output is less than 100% you may be in for an expensive surprise.

Bill
--------------------
"Why not the best?"
Jimmy Carter