Ethylene Storage

http://www.google.co.uk/search?sourceid=navclient&ie=UTF-8&rlz=1T4RNWN_enGB325GB320&q=ethylene+storage

See CR4 Thread Ethylene Storage and Transportation.

Ethylene is extremely difficult to handle it is very unstable and under lower pressures does not want to be either a liquid or a gas. Systems utilised in the old ICI Chemicals were designed around a 1000bar pressure control fed from a Trans Penine pipeline which supplied Ethylene from Wilton on the East coast to Runcorn / Shell Oil refinery on the West coast of Britain. Commissioning of ethylene pipelines has to be rigourously controlled to prevent rapid pressure changes which can lead to two scenarios:

1.American effect ~ Self ignition of ethylene within a pipeline due to decomposition of the ethylene as it becomes etremely unstable at rapid pressure change.

2.Snowstorm effect ~ This is when during pipeline pressure changes the ethylene sub cools the pipework and embrittles it to the extent it will fracture with the least vibration / impact.

In closing I would not recommend trying to store ethylene unless you have the required pressure control systems and metering equipment.

Your post has to be the second biggest set of old wives tales ever. Ethylene is no different than any gas or liquid. It has a criticle pressure and criticle temperature. It obeys the gas laws, yeah it deviates from ideal gas more than say ethane.

If you try to handle C2+ near 800 psia and 50F, you are near the criticle point and it will change phase, gas to liquid to supercritle fluid. So what, it's not it will do anything harmful. Ethylene in that pipeline is transported above it's critical point, so it runs 800 psig to 2200 psig, thats what 55 bar to 160 bar. It is compressed and sent the LDPE reactors at 1000 bar.

The american effect? Lets see, it was a chem plant in Europe that blewup because a pressure gauge inerted with N2 was compressed rapidly and the N2 heat of compression started a run away decomposition. Ethylene by its self can be compressed fast, elese, how would a 300 rpm compressor not blow up going from 800 psi to 15000 psig? No, ethylene becomes a candidate for a decomp because of temperature, not compression.

Pipelines do not fail from the method you stated. I had a 2200 psig line cut and the line depressured. It took us two days to thaw out the ground where the pipe was cut. We installed about 10 feet of pipe. Brought the line back, no embrittlement failures, yep, plain ol carbon steel, -150F, no problemo.

Pressure control or temp control maybe, but metering, what does that have to do with safely storing ethylene?

Now for the op's question. Ethylene is also transported and stored at 200 psig to 250 psig and -40F in the liquid phase. We also stored in in our cascade refrigeration system at -20F and 275 psig. Our system was all rated to 350 psig which allowed the temp to rise to about 0 F if the propane refrigeration loop shutdown.

The other link was full of wives tales on ethylene too. How do I know all this, I published a paper in the early 90's on all this.