sizing turbine 1

[NTRSwamy]

How do turbine manufacturers decide the size of a turbine, for a particular capacity (MW)specified by client ??
For example, if I am specifying the steam conditions as 390 degree centigrade and pressure of 90 bar. the size of turbine will be different for 50 MW or 100 MW capacity.
How is it done??

please share your knowledge

If you cannot explain it simply,you do not understand it well enough.- AE

 

[racookpe1978]

You're confusing and accumulating waaaaay too many different these here - and, indeed, if as you claim "If you cannot ask it simply, you do not understand it well enough ... to be taught easily." 8<)

One. From an (assumed) maximum (or average ?) steam conditions of 390 C at 90 bar, you "might" theorectically be able to calculate the maximum size "perfect" steam turbine that, "might" be able some calculated energy under ideal conditions IF you also gave us the available cooling water flow, cooling water temperature, heat exchanger assumed efficiency (under average conditions, worst-case conditions, and best case conditions) and expected condenser vacuum conditions.

Or, for that assumed steam pressure and temperature, we could assume some atmospheric conditions or some "vented steam" conditions for those cases where you did not want to completely cool the steam to the condenser. The difference in heat energy, plus the assumed efficiencies of the turbine, turbine-to-generator, and generator efficiency could let us calculate what energy "might" be able to be created as a co-gen facility whose output ( steam, electricity, and low-grade heating steam) might be useful.

Or, if you gave us a required output of EITHER 50 Megawatt or 100 Megawatt electrical (?) and those steam conditions AND some assumed condenser properties, then we could calculate whether that much power could be generated at all. (Or, if that much electric could be generated from those conditions, how much steam flow would be required into what sized turbine given some assumed condenser properties.)

Or, let's say you (the customer) already had a 50 (or a 100) Megawatt turbine sitting in your parking lot. (It does happen you know.) Further, let's assume you (the customer) already has steam available at 390 deg C at 90 bar. Then, the question becomes: "How much (electrical) power can I generate using this established equipment from that much established steam properties (and at some assumed flow!) into some assumed condenser properties of cooling water temperature, cooling water flow, heat exchanger efficiency and vacuum."

But without steam flow, steam conditions, and condenser properties we are just guessing.

So, how do real engineers determine what size turbine is required? You (the customer) tells us what he or she wants. Then we (the real engineers) determine what is needed to generate that much under the real-world conditions of that particular power plant during each month (or day) of the year. Needing more information than what you provided.

 

[NTRSwamy]

i understand, that the information was too less to decide the size of turbine.
i am interested in knowing, how different an 50 MW and 100 MW turbine would be ??
what are the parameters considered ??

 

[willard3]

I'll guess that the 100 MW is larger than the 50 MW.

 

[racookpe1978]

Well, if you're looking for sizes, read the following for various low power options at various saturated steam inlet conditions. Remember, 50 MegWatt is a fairly low power turbine.

Note that, at higher steam pressures, and at superheated steam conditions in particular, you can use smaller turbine blades to get the power out.

http://www.energy.siemens.com/us/po...m-turbines-for-geothermal-power-plants_en.pdf

 

[EdStainless]

As has been stated, the turbine is just one piece of the cycle.
Roughly you start with desired generation output, adjust for efficiency, estimate condenser performance, and then you know inlet steam energy (enthalpy and flow). With a small unit there is probably no reheat, or HP/LP staging. So it is a matter of sizing the turbine for the flow needed.
As power goes up turbines get larger and turn slower. Look at the LPs in a NUC plant, they are huge.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[katmar]

In that size range the flow of steam per MW is roughly the same, although the larger unit may be marginally more efficient. So the 100 MW unit will require close to twice the steam flow as the 50 MW unit. Sometimes the client has spare steam and the turbine is sized to use that steam and generate whatever electricity it can. Other times the client has a need for an amount of electricity and then the boiler is sized to generate the required steam.

You can download a free Windows turbine sizing program from my web site. See signature beolw.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[hermit47]

As output power is a production of heat drop to mass flow then if you want to increase power twice you wil need to increase flow rate too. This way the flow path area of each blade row should be doubled. Very rough estimation tells that size will increcsed by 1.44 (sqrt(2)