I'm building the model of a Boiler Feedpump driven by a Backpressure Steam Turbine (unfortyunately looks I cannot attach it...).
I would like to calculate the amount of steam needed by the steam turbine to generate the power required by the pump.
I have inserted an Adjust between the steam to the turbine and the power produced, but now I don't know how to established the setpoint (i.e. the power required by the pump).
I presume this should be given by the 'Use as reference Object' of the Adjust, but by opening it shows me always an empty list.
Thanks for any help.
Luca
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Daniel,
thanks for the model and for the nice solution to the problem.
Unfortunately I am not able to make it to converge.
If I change the feedwater rate to the pump, the steam to the turbine remains unchanged.
Some change appear opening the Adjust panel, but it does not reach the solution.
Once you change the steam flow rate, the Adjust will automatically change it in order to set the pump outlet pressure to 65 bar. There's no need to open its control panel. This is because it is linked to the flowsheet solver (simultaneous adjust solver).
Regards
Daniel
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thanks for the new release. With this it behaves much better.
I had to make a couple of changes in the Adjust in order to have the model to converge: (a) change the Controlled Variable to pumps DeltaP (instead of P discharge); (b) set to 'Yes' the Simultanoeus Adjust (why?). Having done it, it works very well.
I have then added on the steam turbine discharge line the model of a Desuperheater as a subflowsheet (with an UO). It works well and the calculation of the water flow made by the script is correct. But I am not able to get the Streams Table with the right values of the water flow (it's wrong also in the subflo).
I tried a script to put the right values, without luck.
What am I doing wrong?
Finally I wanted to make a link between the pressure on the pump discharge and that of the water to the desuprheater. I used a Spec controller, but it does not work. Why?
In general what is the method for transferring all properties from one stream to another (with Spec only one parameter can be transferred, right?)?
See if this works. There is a problem with compound mapping in the Flowsheet UO but your simulation should work with build 5730. I'll upload a new installer if I have some time tonight .
Mass balance won't close in the subflowsheet because you're setting the mass flow of an inlet stream.
To transfer all properties from a stream to another, use a script UO and the Assign() function. Or you could just connect the stream to the downstream block. If you need the same stream in multiple blocks, then clone it using the procedure I described first.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello everybody,
I'm building the model of a Boiler Feedpump driven by a Backpressure Steam Turbine (unfortyunately looks I cannot attach it...).
I would like to calculate the amount of steam needed by the steam turbine to generate the power required by the pump.
I have inserted an Adjust between the steam to the turbine and the power produced, but now I don't know how to established the setpoint (i.e. the power required by the pump).
I presume this should be given by the 'Use as reference Object' of the Adjust, but by opening it shows me always an empty list.
Thanks for any help.
Luca
Here is the attachment
Hi Luca,
Your simulation will work with this build: http://sourceforge.net/projects/dwsim/files/DWSIM/DWSIM%203.4/build5730.rar/download
Unrar it, and replace the existing files in DWSIM directory.
Use the simulation file below. Remember to save it in DWXML format when possible, it is easier to recover data if the file is corrupted this way.
Regards
Daniel
Thanks Daniel, but after downloading the b5730, my computer says that the file has not the correct rar format. Is a problem at my side?
Luca
Use the latest WinRar version, the file format is RAR5.
Daniel,
thanks for the model and for the nice solution to the problem.
Unfortunately I am not able to make it to converge.
If I change the feedwater rate to the pump, the steam to the turbine remains unchanged.
Some change appear opening the Adjust panel, but it does not reach the solution.
Luca
Hi Luca,
Sorry, I found a few more bugs and corrected them, please try this new build: http://sourceforge.net/projects/dwsim/files/DWSIM/DWSIM%203.4/DWSIM_bin_v34_b5730_beta.exe/download
Once you change the steam flow rate, the Adjust will automatically change it in order to set the pump outlet pressure to 65 bar. There's no need to open its control panel. This is because it is linked to the flowsheet solver (simultaneous adjust solver).
Regards
Daniel
Daniel,
thanks for the new release. With this it behaves much better.
I had to make a couple of changes in the Adjust in order to have the model to converge: (a) change the Controlled Variable to pumps DeltaP (instead of P discharge); (b) set to 'Yes' the Simultanoeus Adjust (why?). Having done it, it works very well.
I have then added on the steam turbine discharge line the model of a Desuperheater as a subflowsheet (with an UO). It works well and the calculation of the water flow made by the script is correct. But I am not able to get the Streams Table with the right values of the water flow (it's wrong also in the subflo).
I tried a script to put the right values, without luck.
What am I doing wrong?
Finally I wanted to make a link between the pressure on the pump discharge and that of the water to the desuprheater. I used a Spec controller, but it does not work. Why?
In general what is the method for transferring all properties from one stream to another (with Spec only one parameter can be transferred, right?)?
Thnaks again.
Luca
Hi Luca,
The attached simulation has a subflowsheet on it, can you attach the referenced file too?
Oops .. here it .is
Luca
See if this works. There is a problem with compound mapping in the Flowsheet UO but your simulation should work with build 5730. I'll upload a new installer if I have some time tonight .
Mass balance won't close in the subflowsheet because you're setting the mass flow of an inlet stream.
Regards,
Daniel
To transfer all properties from a stream to another, use a script UO and the Assign() function. Or you could just connect the stream to the downstream block. If you need the same stream in multiple blocks, then clone it using the procedure I described first.
Here's the new build: http://sourceforge.net/projects/dwsim/files/DWSIM/DWSIM%203.4/DWSIM_bin_v34_b5731_beta.exe/download