Propane deasphalting process

Table 3. Typical Yields and Characteristics of Products Obtained from the Propane Deasphalting Process...

Solvent separation, using the propane deasphalting process, is another procedure by which asphalts of the straight reduced type may be manufactured. This is a physical separation process used to recover high viscosity lube fractions from a given vacuum residuum. When mixed with the residuum, the solvent preferentially dissolves the oil and precipitates the asphalt. 

The most outstanding development resulting from these investigations is the use of liquid propane for the selective precipitation of resins and asphalts. The development of the propane deasphalting process is a very important contribution to petroleum technology in the refining of residual oils and provides a method for substantially complete separation of lubricating oils from the asphaltic materials contained in the residua derived from any crude source. 

The theoretical aspects and operating features of the propane deasphalting process have been described fully (12, 14, 89). 

Within the past five years, the propane deasphalting process has found a place in the recovery of high boiling, desirable catalytic cracking feed stocks with a relatively low carbon content from petroleum residua (57). 

The Demex process is an extension of the propane deasphalting process and employs a less selective solvent to recover not only the high quality oils but also higher molecular weight aromatics and other processable constituents present in the feedstock. Furthermore, the Demex process requires a much less solvent circulation in achieving its objectives, thus, reducing the utility costs and unit size significantly. 

Before explaining the thermodynamic framework of the propane deasphalting process, we present several paragraphs from the 1936 paper by Wilson, Keith, and Haylett to highlight what was known fifty years ago about near-critical and supercritical fluid processing. 

The underlying thermodynamic principles for this process are identical to those exhibited for the propane deasphalting process. This process is yet another example of the use of the unique solvent characteristics of near-critical and supercritical fluids developed some forty years ago. 

This is the oldest patent discussed in this appendix, which was filed in 1927. When we covered the propane deasphalting process in (Chapter 7, we selected some paragraphs from a literature reference that accurately described the technical facets of the process as well as the excitement of the researchers who reported the results (Wilson, Keith, and Haylett, 1936). We have selected a few paragraphs from this patent fw the same purpose the patentee writes,... 

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