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Process For Methane To Methanol


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#1 chemical_teo

chemical_teo

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Posted 18 December 2018 - 03:34 PM

Hi all, 

 

I am currently at the process related aspects of methane to methanol process using zeolites as catalysts. As you may know, zeolites are porous materials in which the methanol mostly stays inside the pores of the catalyst. 

 

As a consequence, I was trying to find ideas to take off all this methanol in the pores. One of my ideas was to apply a vaccum. I have no clue if this is a good idea but I would do it using two reactors with two different pressures, a bit like in PSA but for reactors. Then I would put heat recovery and a condenser to take off all the MeOH. 

 

What do you think? Any other ideas ? 

 

Thanks!

 

Simplifistic proposed flowsheet: 

 

Attached File  Draw03.png   38.94KB   1 downloads


Edited by chemical_teo, 19 December 2018 - 04:17 AM.


#2 Art Montemayor

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Posted 18 December 2018 - 08:12 PM

chemical_teo:

 

My first suggestion and comment to you is to learn how to communicate your thoughts effectively.

You state you are dealing with a process that converts methane to methanol using zeolites as a catalyst.  Fine.  That part communicates OK.  However, you don’t identify the name of the process nor do you describe the reaction type or equipment used - such as drawing a simple process flow diagram.  I don’t think we all know that methanol stays inside the pores of the catalyst.  I thought it was the methane that was the smallest molecule and therefore had access to entering the pores.  Please tell us the name of the process and where we can find details on it, if you can't describe it accurately.

 

Anyway, why are you using/proposing/ an adsorptive catalyst that “traps” your product methanol?  That doesn’t seem to be very practical.  Why not just employ a catalyst that allows free entrance and exit of both the reactants and products?  You fail to explain this query.

 

Consequently, you infer you are trying to “strip” the catalyst of the entrapped methanol product.  Is that what you mean to state?  Does your process design allow for this?  What I mean is that you are imposing a batch type of operation that is not steady state.  You have to have your reactor bed isolated for regeneration and consequently your methanol production is 100% stopped during that period.  Is that what you want?

 

You mention PSA adsorption as an example.  You are totally mixed up with how an adsorption process works.  PSA works only with a pressurized process.  Is your process pressurized? 

 

Please tell our members exactly - and in detail - what you are proposing, together with a flow diagram at least of how the process is supposed to operate.  No process design engineer I know would propose a process where the catalyst would act as a containment trap for the resulting product.  Catalysts become tainted, clogged, worn, and spent after their effective life ceases.  They then are discarded or regenerated - but they are not allowed to get poisoned by the very product they help to produce.  That just doesn’t make much sense.



#3 chemical_teo

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Posted 19 December 2018 - 04:18 AM

Thanks for your reply. We use a catalyst that partially traps methanol simply because it is the most efficient for the moment. Obviously, we would prefer to use a catalyst where the desired product doesn't stay in the pores but we don't have any other solution nowadays. The process I am describing doesn't exist for zeolites (at least for my searches) but I am trying to design a possibility. Therefore, I drew this small simplistic flowsheet (see initial message). Yes, my process is for sure pressurized (around 7-10 MPa). The process however needs to be isothermal. 

 

For the moment I have a distallation column for the separation but maybe a condenser would be enough to condense all the methanol (liquid at room temperature) ?  

 

The proposed reactor is based on a patent I've seen (see Patent RU, 2200731, 2001) .

 

It's basically a PFR with multiple inlets for oxygen... (only one inlet of methane)



#4 Art Montemayor

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Posted 19 December 2018 - 11:27 AM

chemical_teo:

 

I don't think you are telling us all of the "story".  You are a student and you are basing yourself on a partial oxidation process patented by somebody else - but as yet, not operational in the industrial world (for obvious reasons).  Why are you doing this - as a curiosity item?  as an assignment?  as a dare?  It is important to know this in order to determine how much effort can be justified into resolving a lot of the many problems this partial oxidation idea contains.  Refer to my comments in the attached.  Also note that you could have done the same reactor sketch downloading I did - which details more than yours - but you didn't bother.

 

Please answer my questions.

  • How have you come to identify the catalyst as a zeolite that adsorbs methanol?
  • What are the conditions and flows of the process?
  • If you intend to propose a replacement for a syn gas reactor, you are confronting the design of equipment that is going to be formidable in weight and size.  What is the advantage of doing this?
  • How much methanol do you propose to produce?
  • How would you handle the isolation and regeneration of each reactor?
  • Are you restricted to using only zeolite catalyst of a certain pore size that captures methanol?
  • Is no other zeolite pore size applicable?  I may be wrong, but that doesn't sound natural for catalyst action.
  • What would you do with batch-wise produced steam?

 

Attached File  Methane Partial Oxidation Process for Methanol.docx   46.92KB   6 downloads






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