The Ultrex® Process oxidises the sulphur-containing hydrocarbon compounds present in diesel without removing the sulphur from the compound. Having oxidised the sulphur-containing hydrocarbon compounds to form sulphones, the Ultrex® Process then removes the sulphones from the diesel using filtration techniques, leaving ultra low sulphur diesel. Depending on the process by which the sulphones are removed from the diesel, the sulphones may be sold to the chemical industry (if practicable) or else further processed to separate the hydrocarbon compounds from the sulphur compounds with the former being included in the ultra low sulphur diesel to increase the volume of ultra low sulphur diesel returned to the customer.
The Ultrex® Process is undertaken as a separate process after the process of refining crude oil. The Ultrex® Process does not change the diesel’s properties, with the exception of:
- the reduction of the total sulphur content; and
- minor concomitant changes including:
- a slight reduction in lubricity (as sulphur is a lubricant) but not to the same degree as comparable processing by a hydrotreater. Reduced lubricity is easily corrected by using an additive in blending and terminal operations; and
- a slight increase in cetane (which is a desirable characteristic because it provides ignition benefits) as a direct consequence of the removal of sulphur-containing hydrocarbons and this increase in cetane will be greater the higher the initial sulphur content.
The patents filed following final research and development on the Ultrex® Process may be viewed here.
The chemicals used by Ultraclean Fuel to apply the Ultrex® Process are recycled and reused. As part of the registration process for Ultraclean Fuel’s proprietary chemical, Ultraclean Fuel provided analysis to the satisfaction of the USA Environmental Protection Agency in the context of the existing Ultrex® Unit in New Mexico that there is no residue or other by-product from the Ultrex® Process present in the ultra low sulphur diesel produced. This analysis was undertaken by SGS, a leading inspection, verification, testing and certification company.
The amount of energy used by the Ultrex® Process depends on the temperature of the feedstock.If the feedstock is delivered directly from a refinery, then it may need to be cooled to meet the reaction conditions of the Ultrex® Unit. Alternatively, if the Ultrex® Unit receives feedstock from tank storage then the feedstock will need to be heated to meet the reaction conditions.
Ultrex® Units will incorporate a dual redundant mechanical system that is fully automated to IEC 61508/ 61511 SIL2. The estimated life of an Ultrex® Unit is ten years, assuming 350 days of operation each year. This allows 15 days each year for repairs and maintenance. The dual redundancy design methodology of the mechanical system is expected to result in virtually no unplanned down time in a year. This is achievable through remote monitoring of all the mechanical elements of each Ultrex® Unit by reference to mean-time-to-failure data along with algorithms that monitor the performance of the Ultrex® Unit. This combination ensures that if the performance of any component deviates from its long-term average, then preventative maintenance can be performed before the component actually fails or, in the event of a failure, the Ultrex® Process switches to the back-up component. A maintenance team will then take the component off-line and address the problem before it impacts the performance of the Ultrex® Unit.
It is intended to manufacture Ultrex® Units in two standard sizes of 5,000 or 10,000 barrels per day processing capacity. Ultraclean Fuel will provide multiple Ultrex® Units to a customer’s site in a suitable combination of sizes to meet the customer’s needs.
An Ultrex® Unit can be located within a refinery precinct or at a tank farm or pipeline terminal. In any case the Ultrex® Unit will be located within a bunded area for secondary containment with the Ultrex® Unit’s skid mounting providing the primary containment for spillage.
Processing of diesel to produce ultra low sulphur diesel by applying the Ultrex® Process has a significantly lower environmental impact than producing the same result using a hydrotreater. For example, according to publicly available information, Ultraclean Fuel understands that a USA refinery hydrotreating diesel from 350 ppm to 10 ppm would result in an emissions footprint = 28.98kg CO2/barrel compared with 0.74 kg CO2/barrel for an Ultrex® Unit. For those refineries operating in jurisdictions where there is a cost of carbon levied on the business, integration of Ultrex® Units into the refinery to complete the removal of sulphur from (for example) 500 ppm to 10 ppm would allow the hydrotreater to operate at less severe conditions and therefore reduce not only the costs of operation but also the carbon footprint of the refinery.