Urea dewaxing commercial applications

The foregoing shows that the commercial applications of urea dewaxing must lie with lighter waxy cuts because of its selectivity for n-paraffins and their location and distribution in waxy lube cuts. This is indeed the case and it has also been a significant limitation on the application of the technology. Lube refineries normally process a full slate of lubes for economic reasons and the urea technology s inability to handle this meant that its application has been confined to specific feeds. 

In addition to dehazing, the Sonnebom white oil plant also reduced pour point from 4°C to 18°C and cloud point from +4°C to 10°C by removing 3 to 4% wax. This plant was unique in being a batch operation and being the first commercial use of this technology. Here, methanol was used as a promoter for adduct formation. 

Company Location Date Capacity, bpd Products Reference 

Standard Oil Whiting, Indiana 1955 650 Low pour point lubes (— 70°F) for military use in die Arctic and other applications 15, 17, 41 

Deutsche Erdoel AG Heide, West Germany 1955 320 Low pour point diesel and spindle oil 17, 29 

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It should be noted that thiourea, the sulfur analog of urea, also forms clath-rates, but the larger size of the sulfur atom results in larger channels in the adducts which admit compact22 molecules such as branched and cyclic hydrocarbons19 and selectivity is no longer a feature. As a result, no commercial applications of thiourea to dewaxing have been developed. 

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