James M United States

The two patents awarded to Valentine [26,27] concern with desulfurization and both are applicable to the biotreatment of bitumen fuels. The first one deals with desulfurization of Orimulsion , which is a bitumen derived fuel in an O/W emulsion form. Therefore, it seems than the inventor wanted to take the advantage of having the water already incorporated in the feedstock and alleviate the mass transfer limitations of the biotreatment. The second one deals with bitumens in general. 

In these inventions, R. rhodochrous IGTS8 ATCC 53968 [67] can be used, as well as a list of some other patented biocatalysts, such as Pseudomonas sp. CB1 ATCC No. 39381 [7], Acinetobacter sp. CB2 ATCC No. 53515 [8], B. Sulfasportare [16], B. sphaericus IGTS9 ATCC No. 53969 [91], the mixed cultures ATCC No. 39327 [159] and those described in Ref. [160], Valentine discloses the use of all possible biocatalyst types, namely cell cultures (free, immobilized or fragmented), cell extracts, enzyme mixtures (extracted or synthesized) or mixtures of all of them. 

The innovating features of his disclosure are the incorporation of SOx sorbent within the catalytic system to separate the oxisulfides from the reaction medium and the inclusion of more than one biocatalytic stages with intermediate emulsion break-ing/making steps. 

The desulfurization process can be carried out either, in a dedicated reactor, or within a simple storage vessel, or during transportation (in pipelines) or intermediate processing vessels. Nutrients addition, pH, and aeration are adjusted as necessary. Multiple stages can be added to the reaction to enhance the sulfur removal process and decrease the reaction time below the probable 300 h required. The produced sulfates are removed by the addition of agents such as alkaline calcium, magnesium, aluminum, barium, and metal compounds such as oxides, hydroxides, and carbonates. 

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