2 replies to this topic

[syamsundar_menon]

Hi, 

 

I'm a 4th year chemical engineering undergraduate student. I have a design project this year where I have to design a unit operation in a power plant. I've chosen a waste heat boiler as my unit operation. The waste heat boiler essentially recovers exhaust heat from the flue gases that are produced from the combustion in the furnace. However, there is a problem that I'm facing. The course outline of my university says that a good choice of a unit operation should contain at least two (2) of the following elements:

 

•           Mass transfer

•           Heat Transfer

•           Reactions

•           Particle technology aspects such as settling velocities, or population balance models.

 

The problem is, the overwhelming part of the design of the waste-heat boiler is in relation heat transfer, while mass transfer is only a very small aspect of it. I need to have a design that has a balance of two elements from the four elements mentioned above. Is there any way around this? Am I wrong about the fact that mass transfer only plays a small part in the design in comparison to the heat transfer?

 

[breizh]

https://www.cheresou...-boiler-design/

 

https://www.epa.gov/...wer_systems.pdf

 

 

 

Hi ,

let you consider the resource above , you may find pointers. Many more using your favorite engine.

 

Breizh

Edited by breizh, 01 July 2018 - 02:47 AM.

[Saml]

Yes...

 

you can simulate the gas turbine as

- an air adiabatic compressor to 16 to 20 barg (polytropic efficiency from 0.8 to 0.9)

- then mix it with natural gas in an RGibbs  reactor adiabatic and zero delta P (if you are using  Aspen) to produce CO2 and Water (you have to define the reactions)

- then simulate a gas expander from the outlet of the RGIbss to atmospheric again (adiabatic efficiency from 0.8 to 0.9)

 

Vary the air flow, the compression ratio and the efficiencies to match the performance of a commercial turbine (they are published as heat unit of power and mass of flue gas). Also the combustion chamber should be in the range of  1150 °C to  1200°C

 

Use air components (N2, O2, Argon). Do not use the pseudocomponent "Air".

 

Now you have the "reaction" content you were looking for to add in your project. If you do your work carefully, you should obtain an acceptable approximation of actual turbine performance.