(94b) E-FLEX – an Alternative to Increase Propylene to Ethylene Ratio for Liquid Crackers

Since 2000, the majority of plants built in the Middle East and proposed for the US are based on ethane feedstock. In the US, with the implementation of Shale Gas and its inexpensive ethane feed compared to naphtha, many naphtha crackers have been modifying their plants to crack some ethane in addition to their naphtha.  The composition differences between ethane effluent and naphtha effluent from a cracking furnace limit the ethane conversion flexibility to approximately 25% of the fresh feed.  Going beyond 25%, requires extensive investment.  The other impact is a reduction in propylene make which could result in shortages of propylene product with exiting demand.

 The E-Flex process based on a catalytic reaction allows for a lower cost option to modify the cracking effluent from an ethane furnace to make it more similar to the effluent from a naphtha cracking furnace. The E-Flex process, implemented first in an existing facility, will allow a plant to take advantage of the ethane feedstock pricing advantage while keeping both the ethylene and propylene production similar to a naphtha cracker. This can be done without having to make major changes to the cryogenic section of an existing plant. 

 The paper and presentation will explore the new catalyst and process technology; E-Flex and its advantages.  The presenter will also provide data on the yields from the demo plant.  The paper will provide various cases demonstrating the before and after E-Flex material balances. It will provide a comparison of naphtha cracking, naphtha cracking with ethane (ratio 25%) and naphtha cracking with ethane (ratio 25%) using E-Flex process at various severities.  The conclusion will help demonstrate that in cases where the ethylene and propylene ratio should remain constant and is needed, E-Flex technology may be a good fit for naphtha crackers to take advantage and increase their use of the low cost ethane feed.