Process and apparatus for deasphalting and pitch conversion

Abstract

Solvent deasphalting (SDA) is used to extract deasphalted oil from heavier hydrocarbons in series. The pitch stream from solvent deasphalting is calcined to recover volatile hydrocarbon vapor products and calcined solids. The hydrocarbon vapors can be fractionated to recover valuable transportation range fuel products. The pitch stream can be first fed to the fractionation column before calcination.

1 . A process for extracting lighter hydrocarbons from heavier hydrocarbons comprising:
 deasphalting a heavy hydrocarbon feed stream with a solvent stream to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream;   calcining the pitch stream to produce a vapor product stream and provide a calcined solid stream; and   separating said vapor product stream to provide a product stream.   
     
     
         2 . The process of  claim 1  further comprising feeding said pitch stream to a separator before calcining said pitch stream. 
     
     
         3 . The process of  claim 2  further comprising feeding said vapor product stream to said separator. 
     
     
         4 . The process of  claim 3  wherein said separator is a fractionation column and pitch stream absorbs heat from said fractionation column. 
     
     
         5 . The process of  claim 2  further comprising stripping said pitch stream to separate a solvent recovery stream from said pitch stream to provide a stripped pitch stream which is calcined. 
     
     
         6 . The process of  claim 1  wherein said heavy hydrocarbon feed stream is a first pitch stream, said solvent stream is a second solvent stream, said deasphalted oil stream is a second deasphalted oil stream and said pitch stream is a second pitch stream and further comprising:
 deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide said first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. 
 
     
     
         7 . The process of  claim 6  further comprising stripping said pitch stream to separate a solvent recovery stream from said pitch stream to provide a stripped pitch stream, calcining said stripped pitch stream and mixing said product stream with said stripped pitch stream prior to calcining. 
     
     
         8 . The process of  claim 1  wherein said calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated. 
     
     
         9 . The process of  claim 1  further comprising fractionating said vapor product stream to provide a plurality of product streams. 
     
     
         10 . The process of  claim 5  further comprising separating a deasphalted oil stream into a separated solvent stream and a separated deasphalted oil stream and stripping said separated deasphalted oil stream to provide a stripper solvent stream and a deasphalted stream and recycling the solvent recovery stream, the separated solvent stream and the stripper solvent stream to the deasphalting step. 
     
     
         11 . An apparatus for solvent deasphalting comprising:
 an extraction column having a heavy feed inlet and a solvent inlet, a deasphalted oil line extending from an overhead of the first extraction column and a pitch line extending from a bottom of said extraction column;   a calciner in downstream communication with said pitch line; and   a separator in downstream communication with said calciner.   
     
     
         12 . The apparatus of  claim 11 , wherein said calciner has an inlet end and an outlet end and a calcined solids line extending from the outlet end and a vapor product line extending from a top of the calciner. 
     
     
         13 . The apparatus of  claim 11  wherein said separator is in downstream communication with said pitch line and said calciner is in downstream communication with said separator. 
     
     
         14 . The apparatus of  claim 11  further comprising a pitch stripper column comprising a pitch inlet above an inert gas inlet and in downstream communication with said pitch line, and a solvent recovery line extending from an overhead of said pitch stripper column and a stripped pitch line extending from a bottom of the pitch stripper column wherein said calciner is in downstream communication with said pitch stripper line. 
     
     
         15 . The apparatus of  claim 11  further comprising a second extraction column in communication with said pitch line, said second extraction column having a second heavy feed inlet and a second solvent inlet, a second deasphalted oil line extending from an overhead of the second extraction column and a second pitch line extending from a bottom of said second extraction column and said calciner is in downstream communication with said second pitch line. 
     
     
         16 . The apparatus of  claim 11  further comprising a deasphalted oil separator having a separator solvent line extending from an overhead of said deasphalted oil separator and a separator DAO line extending from a bottom of said deasphalted oil separator and a deasphalted oil stripper column having a deasphalted oil stripper inlet above an inert gas inlet and in downstream communication with the separator DAO line and said deasphalted oil stripper column having a stripper solvent line extending from an overhead of said deasphalted oil striper column and a DAO product stream extending from a bottom of the deasphalted oil stripper column. 
     
     
         17 . A process for extracting lighter hydrocarbons from heavier hydrocarbons comprising:
 deasphalting a heavy hydrocarbon feed stream with a solvent to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feed stream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feed stream;   passing said pitch stream to a fractionation column; and   calcining the pitch stream from the fractionation column to vaporize light hydrocarbons and crack heavier hydrocarbons.   
     
     
         18 . The process of  claim 17  further comprising fractionating a vapor product stream from said calciner in said fractionation column. 
     
     
         19 . The process of  claim 17  wherein said heavy hydrocarbon feed stream is a first pitch stream, said solvent stream is a second solvent stream, said deasphalted oil stream is a second deasphalted oil stream and said pitch stream is a second pitch stream and further comprising:
 deasphalting a first heavy hydrocarbon stream with a first solvent stream to extract a first deasphalted oil stream containing a greater concentration of aliphatic compounds than in the first heavy hydrocarbon stream and provide said first pitch stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. 
 
     
     
         20 . The process of  claim 17  wherein said calcining step is conducted in an elongated vessel in which the pitch stream is moved horizontally from an inlet end to an outlet end as it is heated.