Steam Turbine Heat Balance

[Kypros]

Greedings everybody,
I am looking for a spreadsheet or other computer code to do a heat balance on a steam turbine. Does anyone have any idea where I can find one?

Thanks

 

[rmw]

You need to be more explicit as to what you are trying to do. If your application is simple-that is non compound or extraction, I can send you to a couple of good sites.

If you are trying to do a LST then you are going to have to fork over the bucks for a Thermoflow or Gate Cycle or General Physics program and those aren't cheap.

rmw

 

[Kypros]

Our turbines are 30 MW units with 5 point extraction,i.e. 2 Low and 3 High Pressure heaters.

I am not sure I know what you mean by LST.

We are trying to do overall studies on the efficiency of our plant (6x30 MW, range system). Our main problem is lack of accurate flow measurement data, rather, unknown accuracy data.

Thanks

 

[dcasto]

I found a freeware with google. If you go to

http://www.winsim.com,

you can download the steam tables in excel and make your own sheet.

 

[davefitz]

regarding test data accuracy, see the writeups that ASME has as part of the Power Test Codes PTC. Most of the steam turbine performance data to be taken involves enthalpy gains across the feedwater heaters, and flow data might be limited to feedwater or condensate flow. Accurate T + P data at each extraction and admission point would be required, of course.

The use of your own excel table with steam properties may help, but if you do not have the correct procedure , I'm not sure where it will get you. The basis of most simulations of steam turbine performance was the ASME tech papers by Spencer and Cotton , published in the early 1960's. These include curves for predicting or correcting for leakages and expansion line end losses. The main precaution to using these old correlations is that they do not apply to newer LP turbine blades that were designed using 3d CFD and machined using 3d NC machines, in the case of predicting stage efficiency. But if you are only interested in computing test performance, it won't matter.

 

[dcasto]

if the turbine is non condensing you only need 4 pieces of data to get efficency. T&P in T&P out. If you want mechanical efficency, you'll need steam flow and power output.

 

[stgrme]

Perhaps the simplest way to determine efficiency is to measure Heat In versus Power Out. The Heat Rate is the ratio of Heat In over Power Out.

If you can measure the fuel consumed over a specific time period and know the heating value per unit of consumption, you can determine the Heat In.

Most power generating facilities include watt-hour meters for measuring power. These devices are inherently very accurate. If you count the revolutions of the meter over the same specific period of time, used for measuring fuel consumption, and apply a factor for the particular meter you can determine the average Power Out in kilowatts.

Using the Heat In and Power Out calculate the Heat Rate. Compare this measured heat rate to the original design value. In this way, Heat Rate may be determined for the entire plant or for individual units, depending on the plant configuration.

Divide the calculated Heat Rate into 3412.14 Btu/kW-hr (or 3600 kJ/kW-hr) and multiply by 100% to obtain the Thermal Efficiency. Again, compare this measured Thermal Efficiency to the original design value.

Unfortunately, this method will not point to components, which are not performing well.

Good luck with your study!

 

[Berengin]

We develop and supply an on-line calculation software for any integrative turbine parameter. Our experience is based on 525 MWT unit. We supply the packages for Heat Rate, Inernal Efficiency and In- and Out-of-Range calculations. Our methods are based on mathematical (statistical) models preparing for each specific turbine. We have to have any data. Preliminary analysis can show how proper the data is and is it acceptable to define a mathematical model or not. Such analysis is not expensive. Calculation package cost depends on the data available and the specific customer requirements. Any requested information is available by mail - moberman1947@gmail.com

 

[athomas236]

I have tried in the past to use the Spencer, Cotton and Cannon methods (1963 and 1974)to estimate steam turbine performance and have always found them daunting to say the least.

Superficially at least these methods seem to require information about the turbines that may only be available to the supplier. There is also the complication that the predictions are applicable to 60Hz systems and do not appear to give any guidance for 50Hz systems.

For a very simple steam turbine the following link may be useful.

http://www.sugartech.co.za/turbinecalcs/index.php

athomas236

 

[athomas236]

Sorry forgot to mention that there is a UK equivalent of Spencer Cotton and Cannon. It is called "Performance estimation of axial flow flow turbines" and was published in 1070-71 IMechE proceedings.

athomas236