Oil & Natural Gas Projects
Exploration and Production Technologies
Conversion Extraction Desulfurization Process
This project was selected in response to DOE's Ultra Clean Fuels solicitation
The goal of this work is to demonstrate the feasibility of using the Conversion
Extraction Desulfurization (CED) process to reduce sulfur in diesel fuels. This
assessment will include both lab and bench-scale experimental work to test technical
feasibility. An economic evaluation of the process also will be carried out
to demonstrate financial viability.
Petro Star Inc.
On September 20, 2001, DOE contracted Petro Star Inc. to develop its CED process
to remove sulfur from diesel. Petro Star, a small Alaskan refiner, joined with
Degussa Corporation to evaluate the technical and financial viability of the
process. Degussa worked extensively on developing process engineering models
of the CED process that were based on realistic feed compositions and thermodynamics.
The CED process development team demonstrated that CED technology is capable
of reducing the sulfur content of light atmospheric gas oil from 5,000 ppm to
less than 10 ppm at the laboratory scale. In continuous flow trials using rented
equipment, the sulfur reaction capability of the process fell short of the 15
ppm goal by producing fuel with about 20 pm of sulfur. As a result, the technical
development for the project was scaled back considerably, while a marketing
study was completed.
Kline Company performed a marketing study to evaluate the possibility of licensing
the CED technology. Kline found that, out of 143 refineries in the United States,
93 have crude oil capacity of less than 150,000 barrels per day and therefore
qualify for various regulatory exceptions to the Environmental Protection Agency's
(EPA) mid-2006 compliance on producing ultralow-sulfur diesel fuel. Kline interviewed
top management in 43 of the 93 refineries. The conclusion from these interviews
was that only 13 refineries harbored an opportunity for the CED process.
Degussa personnel visited 4 of the 13 refineries in December 2002 over a four-day
period. All four refineries were in the Petroleum Administration for Defense
District (PADD) 3 (Gulf Coast States) and 4 (Mountain States) regions of the
US. All of these refineries use moderate-pressure hydrodesulfurization to produce
highway diesel fuel with sulfur content less than 500 ppm. The management of
these refineries had an open mind toward alternate desulfurization technologies,
especially if the technology could produce ultralow-sulfur fuel at a lower operating
cost. Unfortunately, only one of the three refiners was interested in delaying
compliance past mid-2006.
Based on the information in the Kline marketing study and on the four refinery
visits, the research team decided that further investment in the technical development
of the CED process is not warranted.
Petro Star is developing the CED process to compete with standard hydrodesulfurization
technologies. This will be of particular benefit to small and medium-sized refineries
that do not have hydrotreating capability. The CED process does not require
costly hydrogen processing, high temperatures, or high pressures. The process
selectively oxidizes sulfur compounds and removes them at near-ambient conditions.
It also removes nitrogen-containing compounds and aromatics that adversely affect
EPA has ruled that diesel fuel must contain <15 ppm sulfur by 2006 (with
some exceptions). In order to comply with these regulations, refiners will have
to change the processes that they are now using. The primary method for removing
sulfur from distillates is hydrotreating. Hydrodesulfurization (HDS) processes
consume large amounts of hydrogen, require catalysts that are easily poisoned,
and operate under severe temperature and pressure conditions. These conditions
result in expensive capital and operating costs. There are also disposal problems
associated with spent catalysts and the by-product formation of elemental sulfur.
HDS cannot remove sulfur from the more complex thiophenic compounds without
more severe operating conditions than are presently used in most hydrotreaters.
These increased costs may force small and medium-sized refineries out of the
low-sulfur fuel market. Many of these refineries do not have hydrotreaters now
and cannot justify their construction. Others cannot economically make the upgrades
that will be needed. These refiners need a process that is not prohibitively
expensive for them that will remove sulfur to the necessary levels
The following steps were taken to evaluate the technical and economic viability
of the CED process:
- Develop and optimize CED process.
-Pilot-scale process validation tests. The pilot-scale testing was done by
a contractor. Degussa and Petro Star personnel provided information on previous
work, supervised tests, reviewed data, and incorporate the information into
-Continued optimization tests. This entailed continuing laboratory testing
to take advantage of pilot-scale work.
- Economic evaluation.
-Pilot plant conceptual design. Degussa completed the conceptual engineering
design and cost estimate for a 50 barrels per stream-day pilot plant.
-Update market information. A third-party firm was contracted to conduct a
market study. Petro Star and Degussa developed the specifications for this study,
especially those aspects that involve the analysis of competing technologies.
Current Status (October 2005)
This project is complete. It had two major successes. Petro Star and Degussa
were able to reduce the sulfur in diesel from 3,500 ppm to <20 ppm in a bench
pilot plant without process optimization. Then they off-ramped the project,
based on an economic evaluation of developing the process to where it could
be used in a refinery. There was not enough potential for licensing to justify
further development costs.
Petro Star's refinery at Valdez, AK. Photo courtesy of Petro Star.
The final report has been published.
Project Start: September 20, 2001
Project End: December 30, 2004
Anticipated DOE Contribution: $1,296,060
Performer Contribution: $1,100,663 (46% of total)
NETL - Kathy Stirling (email@example.com or 918-699-2008)
Petro Star - James Boltz (JFBoltz@petro-star.com or 907-339-6614)