5 replies to this topic

[farid.k]

hye all.

 

i planning to construct an liquid ethylene transfer line which estimated length is about 1 km (piping complete with insulation). process information as below

 

fluid: ethylene liquid

transferred flowrate: 8 t/h - 31 t/h

OT: -104 deg. C

OP: 15 barg-10 barg (end point)

Composition, see attached picture.

 

Noted that in the composition is having Max 2ppm of water.

 

based symmetry (process simulation by SLB), there will be no hydrate will be formed. but based on hysys, there will be but didn't mention the amount and i cannot gauge how severe. i trust hysys always conservative in doing calculation and that's why it indicate hydrate formation might occur.

 

i am not sure which one to follow. based on existing transfer line, there is no hydrate formed and i trust, for longer pipeline, it shouldn't too. plus our water content is minimum.

 

Any comment?

Attached Files

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Edited by farid.k, 05 March 2020 - 06:15 PM.

[jayari]

No attachments on the post.

[Bobby Strain]

If a hydrate forms, it would form at the source.

 

Bobby

[farid.k]

No attachments on the post.

thanks. i just upload it again.

[farid.k]

If a hydrate forms, it would form at the source.

 

Bobby

Thanks sir for feedback. say existing facility doesn't have any hydrate concern in the existing piping (from process unit to storage tank which about 800-1000 m), it shouldn't be for new transfer line also isn't?

 

i afraid, the hydrate formation also depending on the transfer piping length and the change of temperature. my new piping will be longer and temperature will drop to certain point and we chill again to get same temperature from the source which is -98 oC which is for me still no reason for hydrate to form.

[PaoloPemi]

supposing  (could be difficult with a 2 ppm fraction) water forms a separate phase, it will be in form of ice or hydrate,

the (lowest)  temperature measurement for C2H4+H2O  hydrate phase which I know is about 200 K (equilibrium pressure about 14000 Pa),

below that (experimental) value one can only guess...

no idea how you can solve phase equilibria including hydrates at  170K  (-104 C)

the software which i utilize (Prode Properties) only allows the range 220-300 K for phase equilibria including hydrates, 

for this range of temperatures  many experimental values are available so you can test the accuracy of models,

outside that range probably you can only guess... 

Edited by PaoloPemi, 06 March 2020 - 05:28 AM.