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Post Hydro-Desulfurization (HDS) Diesel “Finishing”
A significant amount of hydrogen is consumed in the hydro-desulfurization (HDS) or hydrotreating process to remove the final 30-200 ppm of sulfur compounds to meet ultra-low sulfur diesel (ULSD) specifications. The most refractory sulfur compounds almost exclusively belong to one class of sulfur compounds called alkyl-substituted dibenzothiophenes (DBTs). In contrast to the hydrotreating process, these DBTs have shown high reactivity towards the oxidative desulfurization (ODS) process. The primary benefits in this application are significant hydrogen consumption savings and milder operating conditions of the hydrotreater ahead of SulphCo’s Sonocracking™ process resulting in significantly improved catalyst life and lower utility costs. All of these benefits translate directly to a lower carbon footprint, an important issue for customers in the European Union and a growing concern in the U.S. The carbon footprint on the ultrasound-assisted ODS technology is calculated to be significantly lower as the process conditions require significantly less energy than the HDS process and the oxidation reaction with the alkylated DBTs proceeds efficiently.
When an investment decision is involved, the cost-benefit equation becomes even more favorable for SulphCo’s Sonocracking™ process as a diesel stream finishing option. For refineries that are forced to invest in a new hydrotreater or have to upgrade from a low-pressure to a high-pressure hydrotreater to achieve ULSD regulatory limits, SulphCo’s Sonocracking™ technology may be an attractive alternative as a comparatively low capital investment is required.
Other Distillate Streams
In addition, there are a variety of customers that deal with “off-spec” diesel streams and pipeline interface or “transmix” that face more stringent regulation in mid-2010. In most cases, these companies do not have access to hydrotreating capacity and an investment in a hydrotreater is cost prohibitive due to a lack of scale. SulphCo’s Sonocracking™ technology can be the economic solution to protect profitability, remain in business and create additional value.
Other Petroleum Streams
Other opportunities for sulfur reduction using SulphCo’s Sonocracking™ technology in a variety of streams such as natural gasolines and naphthas are being investigated. Initial indications are that Sonocracking™ is an efficient method to reduce sulfur in these streams which may be used as components of the gasoline pool.
Condensates
Certain condensate streams contain specific mercaptan sulfur compounds that respond well to SulphCo’s Sonocracking™ technology, which could provide a cost effective method to allow these streams to meet pipeline specifications, thereby enhancing value and saving transportation costs.
Crude Oil
SulphCo’s Sonocracking™ technology has the potential to create substantial value when applied to crude oils. The drastically increased boiling point of sulfones and sulfoxides compared to their sulfidic analogs allow a redistribution of sulfur species from lower boiling, higher value fractions into higher boiling, lower value fractions in the straight run distillation of the crude oil.
SUMMARY
While SulphCo’s Sonocracking™ process benefits are application specific, there are numerous significant advantages to the process technology as outlined below.
Sonocracking™ can:
• avoid the need for high pressure HDS in the production of ULSD
• reduce or eliminate incremental hydrogen production due to lower HDS requirements
• increase HDS catalyst life by allowing operation at lower temperatures and pressures
resulting in fewer turnarounds and downtime
• debottleneck existing HDS units leading to increased throughput and lower unit cost
• be a lower cost alternative to HDS for low volume applications or CAPEX constrained
projects
• upgrade off-road diesel and heating oil to higher value ULSD
• reduce the volume of high sulfur diesel downgraded to residual fuel
• decrease the requirements for expensive blending components such as biodiesel
• increase the flexibility of crude oil feed slates by providing the ability to use lower
quality crude oils to produce on-spec product
• reduce the carbon footprint because less hydrogen is required and produced
• further reduce carbon emissions due to the lower HDS operating temperatures and
pressures than high pressure HDS operations require
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