Processes for converting hydrocarbon feedstock to pitch compositions suitable for the manufacture of carbon articles

Abstract

Processes comprising: heat treating a heavy hydrocarbon feedstock in a heat treatment unit to produce a first effluent comprising a heat treated product; at least partially removing a mixture of gas and distillate from the first effluent in a first separation unit to produce a second effluent comprising a separation bottom product; deasphalting the second effluent in a second separation unit in the presence of a first solvent to produce: a soluble product fraction comprising a first portion of the first solvent, a deasphalted oil (DAO) product, and a first pitch product; an insoluble product fraction comprising a second portion of the first solvent and a portion of the first pitch product; and at least partially removing the second portion of the first solvent from the first pitch product in a third separation unit to produce a purified pitch product.

What is claimed is: 
     
         1 . A process comprising:
 heat treating a heavy hydrocarbon feedstock in a heat treatment unit to produce a first effluent comprising a heat treated product;   at least partially separating a mixture of gas and distillate from the first effluent in a first separation unit to produce a second effluent;   deasphalting the second effluent in a deasphalter unit in the presence of a first solvent to produce:
 a soluble product fraction comprising a first portion of the first solvent, a deasphalted oil (DAO) product, and a first pitch product portion; 
 an insoluble product fraction comprising a second portion of the first solvent and a portion of the first pitch product; and 
   at least partially separating the insoluble product fraction in a second separating unit to remove the second portion of the first solvent from the portion of the first pitch product to produce an isotropic pitch product.   
     
     
         2 . The process of  claim 1 , wherein the heavy hydrocarbon feedstock comprises a second solvent, wherein the second solvent is selected from the group consisting of: steam cracked gasoil, heavy coker gasoil, heavy vacuum gas oil, heavy extract from lubes production, hydrocracked residue gasoil, steam cracked naphtha, coker naphtha, light cycle oil, reformate, BTX, and any combination thereof. 
     
     
         3 . The process of  claim 1 , wherein the first solvent is selected from the group consisting of: propane, butanes, pentanes, hexanes, heptanes, reformate, furfural, N-methylpyrrolidone, heavy coker gas oil, coker gas oil, light coker gas oil, light cycle oil, and any combination thereof. 
     
     
         4 . The process of  claim 1 , further comprising:
 deasphalting the soluble product fraction in a second deasphalting unit in the presence of a second solvent to produce:
 a second soluble product fraction comprising a first portion of the third solvent, and a deasphalted oil (DAO); 
 a second insoluble fraction comprising a second portion of the third solvent and a second pitch product; and 
   wherein the second solvent has a solubility parameter lower than the first solvent.   
     
     
         5 . The process of  claim 1 , further comprising:
 extracting the insoluble product fraction in the fourth separation unit in the presence of the third solvent to produce:
 a fraction comprising a first portion of the third solvent, and a second purified pitch product; 
 wherein the third solvent has a solubility parameter higher than the first solvent present in the second separation unit. 
   
     
     
         6 . The process of  claim 1 , wherein deasphalting the soluble product fraction provides at least 20% to 25% metals content reduction in the second pitch product. 
     
     
         7 . The process of  claim 1 , further comprising:
 removing particulates from the first effluent by filtration to produce a filtered effluent prior to removing the mixture of gas and distillate in the first separation unit.   
     
     
         8 . The process of  claim 1 , further comprising:
 removing particulates from the soluble product fraction comprising the first portion of the first solvent, the deasphalted oil (DAO) product, and the first pitch product, by filtration prior to deasphalting the soluble product fraction in the fourth separation unit.   
     
     
         9 . The process of  claim 1 , further comprising:
 optionally recycling at least a portion of the second solvent present in the first separation unit to produce a recycled solvent stream;   combining the recycled solvent stream with the heavy hydrocarbon feedstock prior to heat treating in the heat treatment unit or directly in the heat treatment unit.   
     
     
         10 . The process of  claim 1 , wherein heat treating the heavy hydrocarbon feedstock in a heat treatment unit comprise one or more of: a temperature ranging from 350° C. to 550° C.; a pressure ranging from 10 psig to 2000 psig; a residence time of about 5 minutes or greater; and an LHSV in the range of about 0.1 hr −1  to about 12 hr −1 . 
     
     
         11 . The process of  claim 1 , further comprising:
 hydroprocessing or oxidizing, before or after heat treating the heavy hydrocarbon feedstock to reduce sulfur content.   
     
     
         12 . The process of  claim 1 , further comprising:
 hydrotreating (HDT) the separation bottom product in a hydrotreater unit, prior to deasphalting the second effluent, to produce a hydroteated product;   at least partially removing a mixture of gas and heteroatoms contaminants, oxygenates, and metals from the hydroteated product to produce an effluent comprising a purified hydrotreated product that is lower in sulfur, nitrogen and metals than the heavy hydrocarbon feedstock.   
     
     
         13 . The process of  claim 1 , further comprising:
 heat treating the first pitch product and/or the isotropic pitch product to produce a mesophase pitch.   
     
     
         14 . The process of  claim 1 , further comprising:
 optionally sparging a gas through the first pitch product and/or the isotropic pitch product to produce a mesophase pitch.   
     
     
         15 . The process of  claim 1 , further comprising:
 producing a fiber from the first pitch product, the second pitch product, the purified pitch product, the second purified pitch product, or the mesophase pitch product, wherein the fiber is an oxidized fiber, carbonized fiber, graphitized fiber, fiber web, oxidized fiber web, carbonized fiber web, or graphitized fiber web.   
     
     
         16 . A process comprising:
 heat treating a heavy hydrocarbon feedstock in a heat treatment unit to produce a first effluent comprising a heat treated product comprising a gas, a distillate, and a product;   at least partially separating a mixture of gas and distillate from the first effluent in a first separation unit to produce a second effluent;   hydrotreating the second effluent to produce a hydrotreated product;   at least partially separating any gas or distillate from the hydrotreated product in a second separation unit to produce a third effluent;   deasphalting the third effluent in a first deasphalter unit in the presence of a first solvent to produce:
 a first soluble fraction comprising a first portion of the first solvent, a deasphalted oil (DAO) product, and a first pitch product; 
 a first insoluble product fraction comprising a second portion of the first solvent and a portion of the first pitch product; and 
   at least partially separating a mixture of gas and distillate from the first insoluble fraction in a third separation unit to produce a fourth effluent  344  comprising a first isotropic pitch;   deasphalting the first soluble product fraction in a second deasphalter unit in the presence of a second solvent to produce: a second soluble portion and second insoluble portion;
 the second soluble portion comprising a first isotropic pitch, a deasphalted oil product, and a first portion of the second solvent; 
 the second insoluble product fraction comprising a second isotropic pitch and a second portion of the second solvent; and 
   optionally heat treating the first and/or the second isotropic pitch to produce a mesophase pitch product having a mesophase content from about 5 vol. % to 100 vol. %, based on the total volume of the mesophase pitch product, an MCR in the range of about 50 wt % to about 95 wt %, based on the total weight of the mesophase pitch product(s), and a softening point Tp in the range of about 200° C. to about 400° C., wherein the mesophase pitch product is suitable for spinning into carbon articles.   
     
     
         17 . The process according of  claim 16 , wherein either
 (i) the first solvent has a higher solubility parameter than the second solvent, and wherein the soluble fraction from the first deasphalting unit is sent to the second stage deasphalter, and the second insoluble product is a product pitch, or   (ii) the first solvent has a lower solubility parameter than the second solvent, and wherein the insoluble fraction from the first deasphalting unit is sent to the second stage deasphalter, wherein the second pitch is extracted from the first pitch, and the second soluble product is a product pitch after solvent removal.   
     
     
         18 . The process of  claim 16 , wherein the first and the second solvents are both selected from the group consisting of: propane, butanes, pentanes, hexanes, heptanes, reformate, toluene, xylenes, naphthalene, methylnaphthalenes, pyridine, quinoline, furfural, N-methylpyrrolidone, heavy coker gas oil, coker gas oil, light coker gas oil, light cycle oil, and any combination thereof. 
     
     
         19 . The process of  claim 16 , further comprising:
 removing particulates by filtration or centrifugation from:
 the first effluent to produce a filtered effluent by filtration prior to removing the mixture of gas and distillate in the first separation unit; and 
 the soluble product fraction produced in the first deasphalting unit prior to deasphalting the soluble product fraction in the second deasphalter unit. 
   
     
     
         20 . A pitch composition suitable for spinning comprising:
 a pitch having a mesophase content from 5 vol. % to 100 vol. %, based on the total volume of the pitch product, an MCR in the range of about 50 wt. % to about 95 wt. %, based on the total weight of the pitch, and a softening point T sp  in the range of about 10° C. to about 400° C.