Sulfex™ – Desulfurization simplified

Stringent EPA and global environmental regulations are demanding dramatic reductions in sulfur levels in fossil fuels to less than 15 parts per million (PPM) from several hundred PPM.  Currently, desulfurization occurs in a process called Hydro-Desulfurization that uses hydrogen gas, high temperatures (300 to 400 degrees Celsius) and high pressures (30 to 130 atmospheres) to modify sulfur bearing compounds so they can be removed.  However, this process is limited to large refineries owned by companies such as BP and Shell as the capital and operating costs are too high for smaller refineries.   In order to meet the needs of small refineries and pipeline end users, AET has investigated methods to provide a cheaper method of reducing the sulfur content of fossil fuels.

AET has shown that its’ leading edge desulfurization technology, Sulfex™, provides a positive method of controlling reagents used in desulfurization and is fully capable of economically achieving the mandated decrease in sulfur. This results in a more valuable fuel with the same hydrocarbon quality as the original high sulfur fuel.  AET has multiple patent-pending processes that combine high sulfur fuel with a fluid containing a catalyst (either solid or liquid), a material such as hydrogen peroxide and other reagents as needed.  The resulting mixture of the fluid-borne reagents and the hydrocarbon forms an emulsion at high mix rates. This emulsion allows the reaction to proceed in a timely and economic fashion. The catalyst serves the dual purpose of a catalyst and a transfer agent, thus increasing the rate of the oxidation of the sulfur-bearing compounds in the fuel.   Once these sulfur compounds are oxidized, the fluid and fuel are separated, and the sulfur is removed from the fuel.

To date, AET’s laboratory, pilot plant, and small scale industrial plants have resulted in as much as 99.9% reductions of all sulfur compounds found in existing high sulfur fuels and middle distillates sourced from various refineries.  AET has treated 20 different types of diesel and gasoline fuels including U.S. Navy JP-5 jet fuel, U.S. Marine F-75 diesel fuel, high sulfur kerosene, and middle distillates. In addition to dramatically decreasing sulfur levels, AET’s process can simultaneously remove other contaminants such as dirt, water and polar chemical contaminants to comply with EPA regulations.

The main cost-saving advantage of AET’s patent pending Sulfex™ approach is that the fuel is not processed under high temperatures and pressures. It also does not need large amounts of ancillary equipment.  These items are both capital and operationally expensive.  Sulfex™ is also operationally much simpler and thus much safer.

Sulfex Intro Video

Question: What makes AET ODS (SULFEXTM) different from the other ODS methods proposed over the past several years.

Answer: AET’s SULFEXTM process is different than other ODS processes in many ways. The first is that it does not utilize ultrasonics, and thus avoids the entire issue of scalability that is inherent in the industrial use of ultrasonics. The second is that AET has developed the understanding of the issues that surround chemical oxidation under these conditions. This understanding has lead to our ability to offer a system that uses near stochiometric amounts of oxidant and very low dosages of the catalyst material and still achieve the oxidation levels required. This understanding is protected both as trade secrets and patents.

Question: What is the main cost-saving advantage of SULFEXTM?

Answer: Unlike the HDS system currently used at refineries to desulfurize distillate fuels, the main cost-saving advantage of Sulfex is that the fuel is not processed under high temperatures and pressures and thus does not need costly high pressure equipment, large amounts of ancillary equipment, or hydrogen, items that are both capital and operationally expensive.  SULFEXTM is operationally much simpler and thus less expensive and much safer to use than the HDS process currently in use around the world.

Question: Can SULFEXTM be used to reduce sulfur content of heavy oil such as bunker fuel or residual oil?

Answer: Yes, SULFEXTM can be used on heavy fuel oils.

Question: Can SULFEXTM be used to reduce sulfur content of distressed distillates which have high sulfur content such as transmix, lube oils or cycle oils?

Answer: Preliminary data shows that modifications to the SULFEXTM process enable the application of this technology to reduce the color and sulfur content.

Question: Given that the SULFEXTM process utilized hydrogen peroxide, please comment on the safety of the technology?

Answer: The hydrogen peroxide used as the feed to the SULFEXTM process is no greater than 50% hydrogen peroxide, a concentration low enough so that any accidental spill of the material does not create an immediate fire hazard if it contacts organic material. The dosage used for 3000 ppm sulfur levels is 5 mls per liter of fuel, which is perfectly safe for direct contact with the fuel. There are, of course, the usual requirements of personnel and environmental safety as with the handling of any chemical reagent, which is reduced to the minimum by the proper design of the plant and the training of the personnel in the applicable Standard Operating Procedures.

Question: Does SULFEXTM increase oxygen content in petroleum products?

Answer: No, this process does not act as an oxygenation process for fuel. After the reaction in complete, there is no residual peroxide.

Question: Does the product property change after oxidative desulfurization (such as acidity, octane or cetane numbers, flash point, cloud point, boiling point ranges)?

Answer: If the fuel starts as a “within specification fuel” (excepting sulfur) it will be a “within specification fuel” at the end, all of the reagents used in the reaction are removed when the oxidized sulfur is removed.

Question: Does the SULFEXTM process produce sulfur-containing pollutants after the reaction?

Answer: There are no pollutants created in this process. There are, however, two byproduct streams produced. One is clean water; the other is a stream that contains a small fraction of fuel and the oxidized sulfur compounds. This byproduct stream can be handled in several fashions without creating a waste stream, and in many places can be made into a profit generating byproduct

Question: What is the yield of the low-sulfur fuel oil derived from oxidation?

Answer: The testing we have done with heavier fuel oils indicates a loss less than 5%; one must remember that if it starts at 3% (by weight sulfur), that material must be removed, so the minimum loss would be 3% by weight. On lighter fuels, losses are typically 0.6% or less.

Question: What is the efficiency of hydrogen peroxide?

Answer: Theoretically, it requires 2 moles of Hydrogen Peroxide to oxidize one mole of Sulfur at perfect efficiency. Our pilot plant has operated very well at 3 moles to 1.5 moles of H2O2 per mole of sulfur, depending on feed composition.

Question: How are the catalyst and residual oxidant separated from the system?

Answer: Whether we use a liquid or solid sorbent to remove the oxidized sulfur, it also removes the catalyst and any residual oxidant from the system.

Question: What are the types of sulfide in the fuel products after the oxidation desulfurization process?

Answer: The sulfur compounds in the fuel are minimum. The sulfur compounds in the byproduct stream are either sulfones or sulfoxides.

Question: Are there presently operational plants that we can visit?

Answer: No, but we have an operating pilot plant and a small batch plant at our Reno facility that can be visited.

Question: How does the cost compare to HDS?

Answer: Although refineries are reluctant to discuss the true costs of HDS, we can comfortably state that SULFEXTM is no more than 1/3 the capital cost and ½ the operating costs of presently operating HDS plants.

Question: What is the Intellectual Property position of AET and SULFEXTM?

Answer: AET has rigorously worked to patent its new technology since the day of the first major breakthroughs we achieved on non ultrasonic based oxidation. To date, 5 patent applications have been filed, and at least two more are planned.