Enhanced process for the hydroconversion of heavy oils through ebullated-bed systems

Abstract

Process for the hydroconversion of heavy oils, selected from crude oils, heavy crude oils, bitumens from tar sands, distillation residues, distillation heavy cuts, distillation deasphalted residues, vegetable oils, oils from coal and oil shale, oils from the thermodecomposition of waste material, polymers, biomasses, comprising sending the heavy oil to a hydroconversion area, effected in one or more ebullated bed reactors, wherein hydrogen is introduced, in the presence of a suitable heterogeneous, supported, hydroconversion catalyst, in addition to a suitable hydrogenation catalyst, nano-dispersed in said heavy oil, and sending the stream coming from the hydroconversion area to a separation area, in which the separated liquid fraction, containing the nano-dispersed catalyst, is recycled to the ebullated bed reactor(s).

1 . A process for the hydroconversion of heavy oils, selected from crude oils, heavy crude oils, bitumens from tar sands, distillation residues, distillation heavy cuts, distillation deasphalted residues, vegetable oils, oils from coal and oil shale, oils from the thermo-decomposition of waste material, polymers, biomasses, comprising sending the heavy oil to a hydroconversion area, effected in one or more ebullated-bed reactors, wherein hydrogen is introduced, in the presence of a suitable heterogeneous, supported hydroconversion catalyst, and also a suitable hydrogenation catalyst, nano-dispersed in said heavy oil, and sending the stream coming from the hydroconversion area to a separation area, in which the liquid fraction separated, containing the nano-dispersed catalyst, is recycled to the ebullated-bed reactor(s). 
     
     
         2 . The process according to  claim 1 , wherein the separation area to which the effluent stream from the hydroconversion area is sent, if it is in liquid or mixed liquid/vapour phase, comprises one or more atmospheric and/or vacuum distillation and/or one or more flash steps, whereby the separation is effected of the different fractions coming from the hydroconversion reaction, from the distillation residue or from the liquid leaving the sole or last flash step, which is recycled to the ebullated-bed reactor(s). 
     
     
         3 . The process according to  claim 1 , wherein the separation area to which the effluent stream from the hydroconversion area is sent, if it is in vapour phase, comprises one or more high-pressure separators. 
     
     
         4 . The process according to  claim 1 , wherein a purging is effected on the liquid fraction separated containing the nano-dispersed catalyst, recycled to the ebullated-bed reactor(s). 
     
     
         5 . The process according to  claim 1 , wherein the nano-dispersed hydrogenation catalyst is based on Mo or W sulphide. 
     
     
         6 . The process according to  claim 5 , wherein the nano-dispersed hydrogenation catalyst can be formed in-situ starting from a decomposable oil-soluble precursor, or ex-situ. 
     
     
         7 . The process according to  claim 5 , wherein the nano-dispersed hydrogenation catalyst additionally contains one or more other transition metals. 
     
     
         8 . The process according to  claim 5 , wherein the concentration of the hydrogenation catalyst, nano-dispersed in the feedstock, comprising the recycled stream, fed to the hydroconversion area, defined on the basis of the concentration of metal(s) present, ranges from 10 to 30,000 ppm. 
     
     
         9 . The process according to  claim 8 , wherein the concentration of the hydrogenation catalyst, nano-dispersed in the feedstock, comprising the recycled stream, fed to the hydroconversion area, ranges from 3,000 to 20,000 ppm. 
     
     
         10 . The process according to  claim 1 , wherein the supported heterogeneous hydrogenation catalyst is made up of a carrier and an active phase consisting of a mixture of sulphides, one of which deriving from a metal belonging to group VIB and at least one deriving from a metal belonging to group VIII. 
     
     
         11 . The process according to  claim 10 , wherein the metal belonging to group VIB is molybdenum. 
     
     
         12 . The process according to  claim 10 , wherein the metal belonging to group VIII is selected from Ni and Co. 
     
     
         13 . The process according to  claim 10 , wherein the active phase consists of a mixture of sulphides, one of which deriving from molybdenum and one deriving from Ni or Co. 
     
     
         14 . The process according to  claim 10  or  13 , wherein the active phase also consists of acidic sites introduced by either suitably regulating the composition of the carrier or by adding a second phase to the carrier. 
     
     
         15 . The process according to  claim 1 , wherein the hydroconversion reactions in ebullated beds take place at temperatures ranging from 360 to 480° C. and pressures ranging from 100 to 200 atmospheres. 
     
     
         16 . The process according to  claim 2 , wherein the distillation steps are carried out at reduced pressure ranging from 0.001 to 0.5 MPa. 
     
     
         17 . The process according to  claim 17 , wherein the distillation steps are carried out at reduced pressure ranging from 0.01 to 0.3 MPa.