SulphCo’s Sonocracking™ technology employs high power ultrasound to accelerate oxidative desulfurization (“ODS”), an attractive alternative to hydrodesulfurization (“HDS”), the currently practiced method of desulfurization.  In order to meet stringent regulatory limits for ultra low sulfur diesel (ULSD), the HDS process requires extremely high hydrogen and energy consumption operating conditions to treat the most refractory sulfur compounds.  Figure 1 graphically portrays the level of hydrogen consumption as a function of sulfur removal from a typical diesel feed during the HDS process.

         _{Figure 1.  Hydrogen consumption as a function of sulfur removal during hydrodesulfurization.
                            Removal of the last 1% of sulfur required 40% of total hydrogen for a
                            representative diesel stream with 3200 ppm sulfur content.} 

In contrast, the ultrasound-assisted ODS process allows comparably mild reaction conditions such as ambient temperatures and mild pressures.  Ultrasound accelerates chemical reactions by inducing cavitation, which results in strong mixing, high shear and mass transport (Figure 2).

_{Figure 2.  Ultrasound induced cavitation stages from the generation of a bubble (a) through its
                   unstable through its ugrowth (b and c) to the implosion resulting (d) in the release of
                   localized energy.}

SulphCo’s ultrasound assisted ODS Sonocracking™ technology is a potentially more cost effective and energy efficient alternative to HDS. The lower capital cost and smaller equipment footprint suggest a multitude of potential placement options in refinery or other operating settings (Figure 3).

 

_{Figure 3.  Potential placement options of SulphCo’s Sonocracking™ technology in a refinery.
  Cost/benefit analysis suggest diesel finishing as the primary focus area.}

The most attractive deployment of the Sonocracking™ technology exploits the advantages of both processes (HDS and ODS) due to the fact that ODS technology works efficiently on the most refractory sulfur compounds. It is important to note that SulphCo’s desulfurization process consists of two steps, the ultrasound assisted conversion of the sulfur compounds to their oxidized analogs (step 1) and the subsequent removal of these oxidized compounds by a separation technique such as adsorption (step 2).

In addition, there are a variety of customers that deal with off-spec diesel, transmix, natural gas condensate and other streams that face more stringent sulfur level regulations in the near future.  These companies typically do not have access to any hydrotreating capacity and a new investment in a hydrotreater is cost prohibitive.  SulphCo’s Sonocracking™ technology may be an attractive economic solution to create additional value from these streams.

Ultimately, 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 allows 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.  Figure 4 demonstrates the conversion of sulfur compounds during the Sonocracking™ process on treated crude oil.  

                                   _{Figure 4.   Sulfur species distribution of untreated and treated crude oil.
                                                       The oxidized sulfur compounds exhibit significantly increased
                                                        boiling points.}