1 reply to this topic

[sood]

Iam having one demethaniser reboiler operating at 21 degC. What could be the heating media to be used for the reboiler. Normally feed gas after dehydration is used, but in our case no feed is available for the same. Duty is around 5.5 MMKcal/hr. Can we route Propylene Compressor discharge vapors before condenser to provide the duty. Or is it better to install a Low temp Hot oil system for a single Reboiler. Pl help with design.

[pavanayi]

Sood,
We have no idea what plant you are talking about.
We have no idea what streams/ temperatures are available for the case you are talking.
We have no idea about anything regarding the configration of the said propylene compressor..neither about its discharge temperature, nor its discharge flow rate,
We have no idea what desuperheating arrangements you have at the moment for propylene compressor
We have no idea what minimum approach temperature has been established for the plant.
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In short we have no idea about anything.

So it will be with lots of assumptions anyone might be able to help you (which might be applicable, which might not be applicable)


Taking into mind all that,

I will go for a hot oil network only as a last option.
I might not tamper with the refrigeration network until I am very sure what I am doing. Yes the option you mentioned might be a candidate option, but you have to see the existing desuperheating arrangements.
Is the refrigeration compressor having intermediate pressure level discharges that might be suitable?
What temperature is your cooling water supply and return? Can it be used as a heat source?
Is there any existing hot oil/ hot water network?
Is there any option within the process itself to meet your heat demand?

As I said earlier, there is a limit to which we can imagine your system..