Plants Conventional Solvent Lube

KEY POINTS IN TYPICAL CONVENTIONAL SOLVENT LUBE PLANTS... 

Depending upon the specific needs, conventional plants may be converted to hybrid plants to improve capacity and/or product quality. An example of a hybrid configuration is used by Shell to manufacture their XHVI. In this particular case, the plant couples a lube hydrocracker with a solvent dewaxing unit. There are several modifications or improvements of known technologies that can be used as a Mix and Match to Needs to upgrade existing plants. 

The extraction process is a physical separation that is used in all conventional lube plants. The solvent is added to the distillate and then separated to produce a raffinate (the desired product) and an extract that contains a higher percentage of aromatics and impurities. Typical solvents used are N-methyl-2-pyrrolidone, furfural, and phenol. Properties of the solvents are shown in Figure 11. 

There are several types of continuous treater tower designs used in conventional lube plants. These include trayed towers, packed towers and rotating disc contactors (see Figure 13). The treater tower internals are designed to promote contact and separation of the oil and the solvent phases. 

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