Solvent refining processes

The major solvent refining processes include solvent deasphalting, solvent dewaxing, lube oil solvent refining, aromatic extraction, and butadiene extraction. These processes are briefly described below. 

Considerable data have been published and additional unpublished confirmatory data have been collected which indicate that for a given degree of refinement, measured by increased viscosity index or decreased viscosity gravity constant, the quality of refined oils produced by all popular solvent refining processes is so nearly equivalent that there is no clear-cut generalization possible which would favor one process over another. From the point of view of economy, two other considerations are important—namely, selectivity and... 

Raffinate that portion of the oil that remains undissolved in a solvent refining process. 

Other than a slight reduction in sulfur content the filtrate appeared to be thermally stable. Heptane insolubles showed little consistent change. This would be expected since these conditions are very similar to the solvent-refining process environment. 

The important commercial solvent-refining processes are covered every other year in a special Refining Handbook which appears in a monthly issue of... 

Hydrocarbon Processing. In this handbook many licensors of currently available processes present a description of their process along with operating conditions and yields. Numerous solvent-refining processes, including those described below, are covered in this handbook. ... 

Several companies have commercialized lubetreating processes that they now offer for licensing by others. For example, Bechtel offers a process based on the solvent n-methyl-2-pyrrolodine. In their literature, they offer the process flow diagram shown in Fig. 1. Most of the process equipment in Fig. 1 is downstream of the extraction tower, illustrating the effort involved in recovering product and clean solvent for recycle. A major part of the expense associated with this and most solvent-refining processes is the energy... 

Separation processes are often depicted as conventional technologies and these solvent refining processes currently account for about 75% of the world s... 

The raffinate hydroconversion process, developed by Exxon Research and Engineering,30 was developed to upgrade the solvent refining process at Exxon s... 

Figure 6 shows the selective depletion of aliphatic carbons in a coal sample that has been heated at 450 C.9 Similar aliphatic carbon depletions have been noted in 13C CP/MAS studies of reverse combustion and solvent refining processes,9e as seen in Figures 7 and 8. Zilm and coworkers have made extensive use of 13c CP/MAS nmr in a detailed study of a coal liquification... 

The major wastewater from the alkylation process is the spent caustic from the neutralization of the hydrocarbon stream from the reactor. Even though the spent acids are recovered as salable by-product, leaks and spills of acid catalysts could reach the sewer lines. The major pollutants from the solvent refining processes include solvents such as phenols, glycols, and amines. Other processes for the manufacture of waxes and asphalt, and for finishing and blending of gasoline, produce relatively low volumes of dilute wastewater. 

Coal-derived pitch, prepared by a solvent-refining process, was used as a carbon fiber precusor for a short time by Britain s National Coal Board [27]. The process depended upon extensive filtration to remove mineral matter which would otherwise harm the carbon fiber s tensile strength this fact may explain why the process never reached commercialization. Other coal-based processes have been recently reported in Japan, slated for commercialization in 1986 or 1987. 

An ExxonMobil extraction process used to extract aromatics from lube feedstocks to improve the viscosity index and quality of lubricating oil base stocks, integrated with HYDROFINING In solvent refining processes, that portion of the oil which is dissolved in and removed by the selective solvent the solvent rich phase. Contains a low percentage of oil which is typically high in aromatic content. 

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