3 replies to this topic

[Lucas Chia]

Hi there,

I am a Student doing Final Year Project, which required ethylene as my raw material to produce 1-butene. May I know the typical condition of the ethylene are being supply, and in what ways. it is normal that that ehtylene is being stored at around below -0oC condition, and at high pressure ?

Thank you.

[kkala]

Yes, ethylene is usually stored in liquid form under refrigeration. Look at http://www.cheresour...thylene-storage , mainly post No 5. Kind of storage (bullet, sphere, full refrigeration to atmospheric pressure) depends on the quantity stored.
In case of spheres, optimization of ethylene temperature (kept by refrigeration) resulting in specific material of specific thickness should be elaborted.
A simplified way for a student project is to assume several refrigerated bullets (each of about 220 m3 max capacity) of 250 psig design pressure, as indicated in post No 5 of above mentioned web reference. In case of multiple bullets (say more than 5) you can think of a sphere. See also
http://www.cheresour...19-lpg-terminal .

Edited by kkala, 29 January 2012 - 12:43 PM.

[Lucas Chia]

Thank you for your reply,
However, do Ethylene being store in gaseous phase ? say, it is transfer through pipeline, and has higher temperature (around ambient temperature). If so, normal store in gaseous form, it is in what temeperature and pressure condition ? Thank You.

[Art Montemayor]

Lucas:

You are a Student doing his Final Year Project and it involves your using ethylene as raw material. That means you need to allow for storage of the raw material. Knowing this, it is essential that you grasp that you are dealing with what is a gas at normal conditions and in order to justify storage – both economically and practically – you have to consider storage at the LIQUID phase. This is the part of your education where you have to put on your real-life engineering cap and start thinking in a practical, horse-sense manner. You are now beginning to get away from the theoretical, academic realm where you have been studying these past years and start to use the hard-earned knowledge, but in a practical and financially rewarding manner. You must generate a cost-effective design.

Storing a normally gaseous product as a gas is costly, hazardous, and many times impractical. You require compressors and very high pressure equipment that is very specialized and costly. Storing in a saturated, liquid phase is more effective, cheaper, and operationally more simpler and practical. This is where your studies in phase equilibria (thermodynamics) come into play and you have to resort to applying thermodynamic properties and knowledge on phase changes. For quick help and identification of ethylene thermo properties go to: http://webbook.nist....hemistry/fluid/

There you can find and identify all the temperature and pressure conditions under which you can obtain saturated liquid ethylene (ethene). I have been proposing and recommending all Chemical Engineering students to not only get familiarized with this free thermo web site – but also use it at every available moment – for years now. I which all you students would heed the advice of someone who has had to struggle for many years without the benefit of such excellent resources as you have today. You would all profit very handsomely.

Good Luck.