8 replies to this topic

[wingsofdreams]

hi....

I want to read some literature on Ethylene process......Perticularly the available processses,economic process out of it, process description, main equipments and description of it,process flow sheet etc......

Thank you

[ankur2061]

wings,

Did you look up the wikipedia article on ethylene and the various references given in it? There is simply tons of information on ethylene on the internet. What is required is patient searching using google or any other serach engine using various key words about which you ar lloking for information.

BTW, the wikipedia article says that ethylene is the "most produced organic compound in the world".

Regards,
Ankur.

[wingsofdreams]

hi..Mr Ankur...

I already go through that material which is available on wiki or google....I am sorry.....I was expecting something more from the cheresources.....specially a veteran like you.....

Thank you

[robjul]

Hi Wingsofdreams,

I had also been interested and had posted (since last year) about Ethylene but on the other aspect. In particular, it is about a decommissioning procedure on how to evacuate Ethylene from a double-walled cryogenic tank. I know that it's not an easy procedure hence, my request but, am still unlucky till this new year already. Please advise me if ever you found one. Thanks.

[aransari85]

Hi Wingsofdream and robjul,

Happy to see your interest in the ethylene process...

I understand gravity of the subject, etheylene plant is mother of petrochemical complex..

I got a chance to work on ethylene process before in one of the project, where i have to build ethylene process dynamic simulation model, which is used for training purpose and operator effectiveness..

We were having 2 projects running simultanious for ethylene, one was old plant based on B&R technology and one was new plant with latest technology by linde..

Ethylene process varies with licensors, It basically have HOT SIDE and COLD SIDE.

Raw material is ethane, fresh and recycle ethane are cracked in the furncae at about 850deg C, in presence of steam, about 1/3 ratio. furnace is critical operation in the hot side. In the furnace, radient zone is used for the reaction, shield and convection zone is used for feed, BFW heating and HP steam super heating purpose. Hot cracked gased have to be cooled down in short time to avoid side reactions reactions.Reaction time is roughly 0.65sec, outlet of reactor is colled from 850 to 350 deg C in milliseconds in TLE exchangers where HP steam is generated. Outlet of the TLE is used for BFW preheating and at about 150 C just above the dew point of the gas at 2 barg it is fed to quench column where side product fuel oil and steam is condensed and separated. Water is used as reflux in the quench column where multiple entry at different temperature is done to the column. Top of the quench column is at 1.7 bar and about 25 C, send to 6 stage compressor where pressure is increased to 35barg, purpose is to achieve separation between lighters methane, hydrogen, heaviers(propane, C4, C5) in the cold section in the downstream.

Before this gas fed to the cold side it has to be sulfur and water free. to remove sulfur it is contacted with cuastic in caustic tower and dehydrated in molecular seive bed.

Cold Side: to remove methane and hydrogen creacked gas is to cool down to about -100 deg C at demethanizer top and further to -160 C to remove almost all C2 from the ligh gas which we will be feeding as Fuel gas to furnaces. ethylene and propylene refrigeration systems are used,before demethanizer there is complex heat integration scheme having plenty of LNG exchangers.Bottom of demethanizer is feed to de-ethanizer where C3 and heaviers are seperated from bottom and C2 from top having acetylene, ethylene and ethane. acetylene is not acceptable in ethylene so it has to be hydrogenated then feed to C2 Splitter. where side cut from 10 trays from top is taken as pure ethylene having about 300-500ppm ethane. and bottom product ethane is recycled to creacking furnaces. ethylene is further cooled to -100 deg C and sent for storage.

C2 splitter in both projects were different, one is closed circuit using propylene refrigeration and other was open system where top vapors are compressed and cooled and then condensed in the reboiler and feed as reflux. This scheme is for heat integration, which will reduce load on C3 refrigeration compressor.

Ethyelen storage is double walled big tank normally operaing at 10Kpag, at bottom heating arrangement to maintain the bottom sand temperature hot to avoide ice formation. tank having HP pumps to the ethylene vaporizer to feed to downsteam EB/styrene units. Please find some decription about the storage tanks.

This was very brief about the ethylene process.. I dont know what you read in Wiki is more than this?

This was some realistic experiece sharing and i liked to share, i hope this will help you for further knowlege upgrading about ethylene.

If you want some specific details about some unit operation in ethyelen please let me know, i will share as best i can..

Regards,
ARA

Attached Files

•  DOC1.doc   29KB   194 downloads

[wingsofdreams]

Mr ARA,

thanks for sharing a very nice overview of ethylene process....

[kkala]

Thanks Ara for the useful description on ethylene production. As students in 1971 we elaborated a polyethylene (PE) plant feasibility study , so we initially thought of including an ethylene plant from naphtha cracking. The task was limited to low density PE, as soon as complexity of ethylene plant was sensed, http://www.cheresour...l-year-project/ / post No 2. Following notes from that time might be helpful.
1. Ethylene production flow sheets (indicating different processes) were found (and forgotten). Hydrocarbon Processing magazine may be a good source for such flow sheets, accompanied with a description of the process. Characteristics of each process is expected to be reported too.
Note: Chemical age magazine was used to a very limited extent for commercial affairs.
2. Ethylene purification seems an important task. Six distillation columns* are reported to purify ethylene enough for PE production. Absorber, De-ethanizer, Demethanizer, Ethylene fractionator uper section, fractionator lower section, Depropanizer. Photograph / data is given, not flow rates, in "Principles of Unit Operators" by A Foust, L Wenzel, C Clump, etc, John Wiley 1960, Chapter 6 - Countercurrent multistage operations with reflux, p. 52 - 53. Data is presented in attached "Ethylpure.xls" for reference, probably useful if some simulation is tried later on.
3. Steam cracker (http://en.wikipedia....%28chemistry%29) produces additional compounds (beside ethylene) to be commercially optimized.
4. Concerning ethylene storage, you can also look at http://www.cheresour...hylene-storage/.
* some similarity to those mentioned in wikipedia, http://en.wikipedia.org/wiki/Ethylene, Production, para 9 and on.

Attached Files

•  Ethylpure.xls   21KB   162 downloads

Edited by kkala, 26 January 2012 - 05:19 PM.

[Absolute Zero]

Also have a look at Encyclopedia of Chemical Technology

[dkd]

Does anyone have the most common stream compositions in this process? Would like to see it as reference for some simulations.