Equations of residence time can be derived for batch reactor, CSTR and PFR easily by using first principles. But is there any particular method to find residence time of screw conveyor (auger) reactor. I have searched a lot. But I still couldn't be able to find a proper method.
Reactor type - Screw Conveyor
Reaction - Torrefaction (Mild form of pyrolysis)
http://www2.hcmuaf.edu.vn/data/dangnh/file/5_Fenner%20Dunlop_%202009_%20Conveyor%20Handbook.pdf
Abooali Golzary thank you very much for the answer. But I want design facts of Screw Conveyor Reactor. This pdf is only about belt conveyors, not reactors.
Presumably, it can be approximated with the cascade of CSTR, but verification based on dynamic tests will be needed. Regards,
Capcity of screw conveyor reactor will give quanty of materials dicharged per hour. It is nothing but residence time for qunatity of materials discharged by the screw conveyor.
We can increase or decrease the residence time by varying rpm of screw shaft.
In other words, residence time nothing but time taken for traveling of materials from feeding point to outlet point. Less rpm discharge low volume and vice versa..
Mirosław Grzesik Thank you very much for the answer.
But is it accurate to presume a screw conveyor reactor as cascade of CSTRs since screw conveyor reactor has no back mixing?
And also how to determine no of CSTRs if we presume as you told?
Desikan Ramesh Thank you very much for the answer. So are you telling that first I should fix a particular rpm value for screw conveyor as I like and then decide the residence time?
No CSTR, no PFR. But probably closer to the CSTR due to additional mixing. The degree of mixing increases gradually along the tube. So maybe a CSTR cascade with changing ? (decreasing?) residence time. But this is just approximation (model), which has nothing to do with back mixing. Of course, the verification of model based of experiment is neeed. to find the number of reactors and residence time/s. One can also consider as a model, PFR and CSTR connected in parallel. The CFD approach is obviously an alternative Regards
Mirosław Grzesik Thank you very much. Yeah I agree with you. I'll consider this for my design of screw conveyor reactor.
It's just guessing. To be sure, a test should be performed, with an input in the form of a step, impulse or harmonic signal. And then compare the output with the solution of the model's equations. One can further guess and imagine several connected in a series systems: PFR in parallel with the CSTR. Regards,
Mirosław Grzesik Yeah it's true . But for my project, we couldn't do any test regarding for this reactor. So at this stage, we have to review literature and do this design based on other's researches. Therefore some calculations may be bit hypothetical. But your answer would be really helpful and also I have read a report in which they have assumed their screw conveyor reactor as a CSTR for their design. So thank you for answer.
If we take into account only input and output and what it is inside as a black box , it is possible to treat such system as CSTR but probably with no ideal mixing. There are such models. Regards,
There were some magazine articles about it about 40 years ago, when I was working on it.
Mirosław Grzesik Yes, it's true. Therefore more assumptions has to be taken and so the accuracy can be less. I'll consider it. Thank you very much!
Jerry Decker , Is it so. Nice to hear so from an experienced person. Did you have to design it or purchase a designed screw conveyor reactor?
Desikan Ramesh Thank you very much. I'll refer this for my design.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Energy