3 replies to this topic

[Jeexl]

Dear reader,

I'm a student from the Technical University of Delft in the Netherlands studying marine engineering (system integration on ships).
For my master thesis I'm researching the possibility of a nuclear reactor in a Short Sea Shipping Container Vessel. The idea is to couple a HTR (High Temperature Reactor) to a open loop gasturbine. I have a closed loop runing through the reactor 40 Bar Helium with reactor inlet temperature of 450 °C and a reactor outlet temperature of 950 °C.
The another closed loop filled with nitrogen which I can vary in all properties.
And at the end a open loop gasturbine (running on normal air) heated by the heatexchangers between these loops. The gastrubine has a temperature of 400 °C and a pressure of 12.5 bar after the compressor and needs a temperature as high as possible at the turbine to maintain a decent efficiency.
These loops are all divided into two seperate loops for redundance and lead to 2 gasturbines. The thermal heat transferred is 42 MW.

I thought the nitrogen loop to be in between the 12.5 and 40 bar to keep the stresses in the heat exchanger as low as possible. Plate heatexchangers are not yet develloped for these temperatures
so Shell and Tube is the only solution.

The material I found that could handle these high temperatures was 2111HTR or S30815, the only problem is that I'm having a hard time finding the ultimate stresses at these high temperatures.

I used a linear heattransfer coefficient to calculate the heat in the tubes. I divided one heatexchanger into 15 parts to simulate the baffles. And I calculated the stresses at the inner surface of the tubes.
I assumed a surface packingfraction to estimate the diameter of the whole vessel.

I included my excell sheet.

Now the question is: Is this the right path to estimate the heatexchanger, is approximately 15 ton weight a proper estimate for such a heatexchanger?

Thanks in Advance for the help and interest!

Attached Files

•  Heatexchanger.xls   84.5KB   92 downloads

[Jeexl]

I forgot to tell the temperature difference in the different parts of the heat exchangers drops to 3.8 degrees difference assuming a 95 % efficiency on ideal mixing, is this possible?

[process equipment]

hi,

do you have a drawing or a p&id to get a better view on your problem. Is this a heatexchange problem or a stress problem ?

[Jeexl]

Here is a schematic and a sketch of the situation probably applicable.
I also updated my sheet but by now it is soo large, someone who didnt write it will need days to figure out how to use it. The basis is still the same though.

The problem is bothways, is a linear model sufficient to describe a tube and shell HE. And for stresses: what are the material properties in the higher ranges. I only got the properties of the material up to 700 degrees celcius.

hi,

do you have a drawing or a p&id to get a better view on your problem. Is this a heatexchange problem or a stress problem ?

Attached Files

•  Schema.jpg   45.04KB   46 downloads
•  Reactorcompartiment.jpg   279.54KB   48 downloads