Petrochemicals Without Refining? New
Process Allows the Production of Ethylene Directly from Crude
Exxon Mobil's Singapore chemicals plant, a favorable
location for the new oil to chemicals process, thanks to ist access to light
and sweet crudes. (Picture: Exxon Mobil)
Bye-bye, naphtha cracker: A new steam
cracking process allows petrochemical producers to skip the refining stage in
the production of ethylene – with potential cost benefits of hundreds of
dollars per ton.
Houston, Texas USA– Two new steam-cracking processes developed by
Exxon Mobil and Saudi Aramco, respectively, allow petrochemical producers to
essentially skip the refining process in converting crude oil directly to light
olefins. These new processes could potentially save refiners as much as
$200-per-ton of ethylene produced, according to a comprehensive engineering
analysis conducted by IHS (NYSE: IHS), the leading global source of critical
information and insight.
“In 2014, Exxon Mobil commissioned a world-scale facility in
Singapore that produces 1 million tons per year of ethylene directly from crude
oil,” said Anthony Pavone, director of engineering at IHS Chemical. “We at IHS
Chemical believe this process nets Exxon Mobil about $100 to $200 per metric
ton above traditional naphtha cracking.”
“This new crude-to-olefins process is about production cost
savings, and takes advantage of the premium that naphtha commands over crude
oil in Southeast Asia. It is this ‘feedstock spread’ that contributes most of
the cost-savings advantage,” Pavone said.
Crude to Olefins: How the Saudis enter
the Next Petro-Level
The Exxon Mobil process completely bypasses the traditional
naphtha cracking process. Saudi Aramco has its own process for crude oil to
olefins, and in June 2016, Aramco announced a joint venture with Sabic to study
building a ‘crude oil-to-chemicals’ complex in Saudi Arabia. Though the exact
process configuration for the potential joint-venture was not disclosed, it is
possible this complex will employ the Aramco process, at least in part.
According to the IHS report, the Exxon Mobil process completely
bypasses the refinery and feeds crude oil to the cracking furnaces. These have
each been modified to include a flash pot between the convective and radiant
sections of the furnaces. Next, the crude oil is pre-heated and then flashed,
IHS said, essentially ‘topping’ the lighter components from the crude.
Favorable Locations: Light and Sweet
Crude Required
This extracted vapor, the IHS report said, is then fed back into
the furnace’s radiant coils and cracked in the usual fashion. The heavier
liquid that collects at the bottom of the flash pot is either transferred to
the adjacent Exxon Mobil refinery, or sold into the merchant market.
“This analysis was conducted at a $50 per barrel cost for crude
oil,” Pavone said. “As you might expect for Singapore, this process requires
the local availability of light, sweet crude.”
The Aramco process, IHS said, works along an entirely different
concept from that of the Exxon Mobil crude-to-olefins process. As of yet, IHS
cautioned, the Aramco process is still only a proposed project; no facility
actually has been built to test the process.
The IHS report said the Aramco process begins by feeding the whole
barrel of crude to a hydrocracking unit, which removes sulfur and shifts the
boiling point curve significantly toward lighter compounds. The gas-oil and
lighter products are sent to a traditional steam cracker, while the heavier
products are sent to a proprietary, Aramco-developed deep-fluid catalytic
cracking unit (FCC) that maximizes olefin output.
A 200 Dollar per Ton
Benefit
“We at IHS Chemical estimate the cash-cost for this Aramco
crude-to-olefins process would be $200-per-ton cheaper than for a naphtha
cracker,” Pavone said. “The hydrocracker and deep-fluid catalytic cracker add
significant capital costs, though, so at 15 percent pre-tax return on
investment (ROI), we estimate the Aramco process would pencil in at roughly
equivalent costs to naphtha cracking in Saudi Arabia.”
The IHS report is based upon a “bottoms-up” Class-3 process design
and proprietary steam cracking kinetic reaction software simulation of both the
Exxon Mobil and Saudi Aramco crude-to-olefins processes. “To the best of our
knowledge,” Pavone said, “our IHS Chemical analysis is the first in-depth
independent analysis of these new crude-to-olefins technologies.”
Editor: Dominik Stephan
http://www.process-worldwide.com/petrochemicals-without-refining-new-process-allows-the-production-of-ethylene-directly-from-crude-a-541196/l
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