5 replies to this topic

[Araboni]

Dear all

We intend to import ethylene gas stored in 80 lit cylinders into our factory and with the aim of compressor and condenser (equipped with propane refrigerant at 5 °C and pressure of 55 barg ) make it condense and then send it to a horizontal cylindrical tank.

As you know, the critical temperature and press of ethylene is 9.5 °C and 50 bar , respectively. So, the question I have is whether, or not the liquefaction of ethylene at 5 °C and 55 barg is feasible. Have you ever had any experiences of liquefying ethylene in such a situation? Please note that we do not intend to store ethylene in atmospheric press and temperatures of -100 °C.

I was wondering if anybody can help me.

Regards

Araboni

Edited by Araboni, 16 November 2021 - 01:47 AM.

[Pilesar]

I have experience liquefying ethylene, but not in such a situation. I will comment on a few things. 'Propane refrigerant at 5 °C and pressure of 55 barg' is probably not in a closed-loop refrigeration system. If this is to be a commercial-sized unit, investigate whether there might be an advantage to reducing the propane pressure in a turbine instead of across a valve. Consider the terminal pressure needed for the propane.

  Ethylene gas safely stored in cylinders is already at very high pressure. I would look at using it from the cylinders instead of transferring it to other storage. Ethylene can exist at 5 °C and 55 barg but there would be no liquefaction since two phases are not distinguishable at these conditions. I would consider keeping the ethylene stored at high pressure in ambient conditions and just cooling it when required for processing if it is needed at lower temperature..

[Araboni]

Pilesar

Thank you for the respond. Please note that the propane refrigeration cycle works in subzero temperature conditions. If we want to use directly ethylene gas cylinders, due to the high consumption of this feed, a large quantity of cylinders are needed per hour, which is not logical at all. So we have to store ethylene in liquid conditions, but not at temperatures near -100 °C. Considering that the critical temperature of ethylene is 9.6 °C, at 5 °C and pressure above critical pressure, Shouldn't it be completely a saturated liquid?

Edited by Araboni, 16 November 2021 - 07:48 AM.

[Bobby Strain]

Check a Mollier diagram. Sounds like cylinder gas supply is not workable. Look to receiving liquid ethylene in iso containers. And a vaporizer system.

 

Bobby

Edited by Bobby Strain, 16 November 2021 - 10:23 AM.

[Araboni]

Bobby thank you...

Regarding the type of Shell and Tube Steam vaporizer for liquid Ethylene, Do you have any idea for the proper TEMA type of exchanger?

Regards

[Bobby Strain]

You should look to a system supplier for the complete system. It's not something you should consider designing yourself. Talk to your potential  ethylene suppliers. Where is your plant located? Use your favorite web search engine. You should find Chart Industries among suppliers.

 

Bobby

Edited by Bobby Strain, 17 November 2021 - 01:16 PM.