Notwithstanding reduced purity of products, is it possible to improvise a fixed bed reactor (see attached file) by simply mixing the CaO with terephthalic acid in a test tube such as the one in the video link?
https://www.youtube.com/watch?v=JhUxaNesnxs
For demonstration purposes, the compounds in the video are poly(ethylene) terephthalate (PET) and NaOH -- not the ones I'm proposing to use. However, pyrolysis is the process to be employed in producing benzene.
Thanks in advance.
TPA can be decarboxylated in the presence of calcium oxide (CaO) to obtain benzene as the main product. However, high concentrations of TPA cause the formation of large char fractions, reducing the yield of desired products. In this investigation, TPA can be decarboxylated using a fixed-bed reactor filled with CaO. To increase the yield of benzene and reduce the carbonaceous residue, the effects of pyrolysis temperature and TPA feed rate must be investigated. The best results will be achieved at 500 °C and a TPA feed rate of 51 mg L−1, yielding 67% benzene with a purity of 99.2% and a carbonaceous residue containing 18% of the initial carbon, according to recent studies.
Dear Tristan,
It is a very interesting process. Industrially it is rather complicated to carry out in a fixed bed. I suggest to use a fluid bed for contacting and reaction. The process would open up different fluid bed tyoe of operation, from batch or semibatch to continuous.
Regards
In my opinion, it depends. If you would like to get information on the chemistry, you could improvise the fixed bed by simple mixing, but I would rather call it then stirred reactor. If you would like to examine heat and mass transfer, simple mixing would not get you anywhere.
I agree with Dr Reif´s opinion. Let me add the following thoughts. Of course, kinetics should be studied in a differential packed bed in which ppint rates could be measured and regressed. Or else an equivalent equivalent CSTR reactor, where mass transfer effects could be figured out. Then integral fixed bed reactor runs, can be done to ascertain kinetics.
With the kinetic knowledge, fluid bed should be considered when going to an industrial reactor at a bench scale/pilot scale. Not a fixed-bed process.
Regards
Francesc Recasens (UPC, Barcelona)
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