(November 21, 2019) — The petrochemical market information provider ICIS reports that a number of flex-feed crackers are likely to continue favoring LPG as a feedstock because costs for propane and butane remain at a relatively small spread to those for ethane, and because of higher coproduct prices for propylene.

This is because there is not currently enough on- purpose propylene production capacity to meet demand, so the industry is dependent on the monomer being created as a coproduct of other chemicals. Therefore, until the arrival of more on-purpose propylene production plants such as propane dehydrogenation (PDH) and metathesis units, heavier feedstocks will continue to see some use in ethylene production. Propylene is produced as a coproduct of ethylene production through the steam cracking, or steam pyrolysis, of hydrocarbon feedstocks. Feedstocks used for steam cracking range from ethane to naphtha and gasoil. Propylene is also produced as a by-product of petroleum refining.

The sustained use of heavier feeds, even with ethane’s considerable cost advantage, is allowing crackers to obtain higher margins. This cost advantage for ethane has encouraged ethylene producers to build steam crackers designed to crack only ethane feedstock.

As of July 2019, a least one quarter of all U.S. cracking capacity was comprised of ethane-only crackers, according to Hodson Report data. Due to ethane’s rise as the preferred ethylene feedstock, propane, butane, and heavier feeds only account for about 25% of the ethylene feed slate, down from nearly 50% a decade ago.

But despite the trend toward ethane crackers, the use of propane, butane, and heavier feeds is still increasing on a volumetric basis, up from 500,000 bbld last summer to more than 600,000 bbld currently, according to figures from Daniel Lippe, managing partner at Petral Consulting.

Ethylene is a key petrochemical feedstock used to make polyethylene, ethylene glycol, and polyvinyl chloride, among other products. Major U.S. ethylene producers include Chevron Phillips Chemical, Dow DuPont, Exxon- Mobil, INEOS Olefins & Polymers, LyondellBasell, and Shell Chemical.

The main outlet for propylene is as a feedstock for polypropylene. Polypropylene is also used to produce acrylonitrile, propylene oxide, a number of alcohols, cumene, and acrylic acid. Major U.S. producers include Chevron Phillips Chemical, Enterprise Products, ExxonMobil, Flint Hills Resources, and Shell Chemical.

(SOURCE: The Weekly Propane Newsletter, November 18, 2019)