[thackney]

But ethane is the feedstock to make ethylene.

I took that as the part of the process being replaced since the referenced a refinery and not a chemical plant

[Ben Ficklin]

If you steam crack naptha(a liquid) you get ethylene, propylene, and other compounds.

The advantage of using naptha over natural gas is you are not exposing yourself to wide swings in the price of natural gas. In the last 10 years we have had two bouts with natural gas shortages and resulting price spikes. Post Katrina price increases never went down until the economy collapsed. We get most of our oil from the world supply but our nat gas comes from the domestic supply.

Now, the nat gas supply is stable and abundant so using nat gas is preferable. But, Katrina's little sister could come thru the gulf next year