SEPARATION OF SELECTED ASPHALTENES FROM A HYDROCARBON-CONTAINING FEEDSTOCK

Abstract

Toluene-insoluble hydrocarbon-containing compounds are selectively separated from a hydrocarbon-containing feedstock containing at least 5 wt. % n-heptane insoluble hydrocarbon-containing materials, wherein at least 10 wt. % of the n-heptane insoluble hydrocarbon-containing materials are toluene insoluble hydrocarbon-containing materials, by contacting the hydrocarbon-containing feedstock with a porous silica adsorbent having a median pore size diameter of less than 180 Å at a temperature of from 120° C. to 300° C.

Description

RELATED CASES

This application claims benefit of U.S. Provisional Application No. 61/842,689, filed on Jul. 3, 2013, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to separation of selected hydrocarbon compounds from a hydrocarbon-containing feedstock. In particular, the present invention is directed to separation of at least a portion of toluene insoluble hydrocarbon compounds from a hydrocarbon-containing feedstock.

BACKGROUND OF THE INVENTION

Hydrocarbon compounds and heteroatom-containing hydrocarbonaceous compounds that are insoluble in n-heptane (referred to herein as “n-heptane insoluble compounds”) are typically present in crude oils and may also be formed when thermally cracking, hydrocracking, or hydroprocessing crude oils or crude oil fractions such as atmospheric residues or vacuum residues. These compounds are generally composed of polyaromatic carbon ring units, and may contain oxygen, nitrogen, and sulfur heteroatoms, and are often combined with trace amounts of heavy metals such as vanadium and nickel. These compounds are not composed of a single molecular species, but are a range of molecular species generally having a distribution of molecular masses in the range of 400 to 1500 daltons.

Such compounds often cause problems in oil production, processing, and, transportation due to instability of a portion of the compounds in the oil as the oil undergoes changes in composition, temperature, and pressure. Oil refining or upgrading processes in which oil or a fraction thereof is heated to temperature of 350° C. or above such as thermal cracking, hydrocracking, catalytic cracking, and hydroprocessing processes generate particularly unstable n-heptane insoluble compounds, where a significant portion of the unstable n-heptane insoluble compounds may be toluene insoluble compounds that are not present in the oil or oil fraction prior to processing the oil at a temperature of 350° C. or above. These unstable n-heptane insoluble compounds may flocculate and precipitate to form a separate solid phase in oil. Otherwise stable n-heptane insoluble compounds may combine with the flocculate to produce more solid material. In transport of hydrocarbon fluids, these unstable n-heptane insoluble compounds may induce hydrocarbon precipitation in pipelines, blocking the flow of oil through the pipeline. Furthermore, if oil or an oil fraction containing these compounds is to be processed at temperatures over 350° C., the unstable n-heptane insoluble compounds may act as coke-forming precursors that induce the formation of coke at elevated temperatures.

Various measures have been used to reduce phase instability or coke formation induced by unstable n-heptane insoluble compounds. One such measure involves separation of n-heptane insoluble compounds from a crude oil or a crude oil fraction by deasphalting. Deasphalting processes precipitate n-heptane insoluble compounds from a crude oil or a crude oil fraction by mixing the oil with an excess of n-pentane or n-heptane, where the precipitated compounds are physically separated from the crude oil or crude oil fraction to produce a deasphalted oil. The deasphalted oil may then be processed at elevated temperatures with little or no coke formation or transported with little or no asphaltene precipitation. These measures, however, reduce the overall recovery of valuable hydrocarbons by separating valuable hydrocarbons from the oil along with the undesirable compounds.

Another measure that has been utilized to reduce n-heptane insoluble compound induced phase instability in a hydrocarbon-containing feedstock entails mixing a diluent with the hydrocarbon-containing feedstock to stabilize n-heptane insoluble unstable compounds in the feedstock and thereby inhibit flocculation and precipitation induced by such compounds. The diluents typically contain a significant quantity of aromatic hydrocarbons since n-heptane insoluble compounds are stabilized within a liquid hydrocarbon phase by aromatic hydrocarbons. The diluents may be a fraction of a crude oil such as kerosene, diesel, toluene, or o-xylene, or may be a whole crude oil such as bitumen. For example, the residue stream of hydrocracked vacuum residue may be stabilized for transport by blending the residue stream of the hydrocracked vacuum residue with bitumen. Dilution, however, typically reduces the value of the diluents, where the diluents often are of greater value than the hydrocarbon-containing feedstock containing the unstable n-heptane insoluble compounds.

Still other measures for reducing phase instability or reducing the quantity of coke-forming precursors in a hydrocarbon-containing feedstock containing n-heptane insoluble compounds have been effected by contacting the hydrocarbon-containing feed with an adsorbent and separating an oil product from the adsorbent. U.S. Pat. No. 4,624,776 provides a process where an atmospheric or vacuum residuum fraction of oil is contacted with an adsorbent, then the adsorbent is contacted with a solvent having selected solubility characteristics to desorb a first portion of the residuum that is depleted in coke-forming precursors from the adsorbent, then the adsorbent is contacted with a second solvent having different solvation characteristics than the first solvent to desorb a second portion of the residuum that is enriched in coke-forming precursors. This process requires at least two solvents to recover the residuum portions from the adsorbent. U.S. Pat. No. 6,245,223 discloses separation of metals and coke precursors from a hydrocarbon stream by contacting the feedstream with a hydrocarbon insoluble adsorbent such as silica, silica-alumina, acid-treated clays, or activated carbon, at temperatures of up to 200° C. and recovering the oil which does not adsorb, then removing the metals and coke precursors from the adsorbent with a solvent. The hydrocarbon streams treated in this process do not include hydrocarbon feedstocks that have been previously treated at temperatures of at least 350° C. and do not include a significant quantity of toluene insoluble compounds.

It is desirable to provide a process for selectively removing phase unstable n-heptane insoluble compounds from a hydrocarbon-containing feedstock where the n-heptane insoluble compounds are comprised of a significant quantity of toluene insoluble compounds. The hydrocarbon-containing feedstock may have been previously treated at a temperature of at least 350° C.

SUMMARY OF THE INVENTION

The present invention is directed to a process for separating toluene insoluble compounds from a hydrocarbon-containing feedstock, comprising:

providing a hydrocarbon-containing feedstock comprising at least 5 wt. % n-heptane insoluble hydrocarbon-containing materials, wherein at least 10 wt. % of the n-heptane insoluble hydrocarbon-containing materials are toluene insoluble hydrocarbon-containing materials, and wherein n-heptane insoluble hydrocarbon-containing materials are hydrocarbon-containing materials that precipitate from a liquid hydrocarbon-containing material in a 40:1 volume mixture of n-heptane:liquid hydrocarbon material at 25° C. and toluene insoluble hydrocarbon-containing materials are materials that precipitate from a liquid hydrocarbon-containing material in a 40:1 volume mixture of toluene:liquid hydrocarbon material at 25° C.;

contacting the hydrocarbon-containing feedstock with a porous silica adsorbent at a temperature of from 120° C. to 300° C., wherein the silica of the silica adsorbent has a pore size distribution having a median pore size diameter of less than 180 Å as determined by mercury porosimetry;

separating a hydrocarbon-containing product from the silica adsorbent, wherein the hydrocarbon-containing product contains at most 50% of the toluene-insoluble hydrocarbon-containing compounds of the hydrocarbon-containing feedstock.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing is a diagram of a system for practicing the process of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a process for separating toluene insoluble hydrocarbon-containing compounds from a hydrocarbon-containing material, where the toluene insoluble hydrocarbon-containing compounds form a portion of n-heptane insoluble hydrocarbon-containing compounds that are present in the hydrocarbon-containing material. Such toluene insoluble compounds are formed in substantial quantities in a hydrocarbon-containing material by treating a hydrocarbon-containing material at a temperature of at least 350° C., typically from 375° C. to 450° C., in a thermal cracking, hydrocracking, catalytic cracking, or hydroprocessing process. As shown by Schabron in U.S. Pat. No. 6,773,921, these toluene insoluble compounds are particularly responsible for inducing coke formation in a hydrocarbon-containing material relative to other n-heptane insoluble compounds in the hydrocarbon-containing material. Applicants have found that these toluene insoluble compounds, relative to other n-heptane insoluble compounds, are also particularly responsible for inducing phase instability in a liquid hydrocarbon containing-material leading to flocculation and precipitation of hydrocarbon-containing solids.

The process of the present invention preferentially separates a toluene insoluble fraction of an n-heptane insoluble fraction of a hydrocarbon-containing material from a hydrocarbon-containing material. Hydrocarbon compounds and heteroatom-containing hydrocarbonaceous compounds that are less likely to induce coke formation or liquid phase instability may be retained in the hydrocarbon-containing material, including a substantial portion of toluene soluble, n-heptane insoluble compounds. As a result, the process of the present invention specifically targets removal of hydrocarbon-containing compounds from a hydrocarbon-containing material that are most likely to induce coke formation upon processing the hydrocarbon-containing material or that are most likely to induce phase instability in the hydrocarbon-containing material by flocculation and precipitation of hydrocarbon-containing solids from the hydrocarbon containing material.

Certain terms used herein are defined as follows:

“Hydrocarbon-containing” compound is a compound comprised of carbon and hydrogen atoms. A hydrocarbon-containing compound may be a hydrocarbon or may be a heteroatom-containing compound comprised of carbon and hydrogen atoms in combination with one or more heteroatoms.
“n-Heptane insoluble material or compound” is defined as a material or a compound, respectively, that precipitates from a liquid hydrocarbon-containing material in a 40:1 volume mixture of n-heptane:liquid hydrocarbon material at 25° C.;
“Toluene insoluble material or compound” is defined as a material or a compound, respectively, that precipitates from a liquid hydrocarbon-containing material in a 40:1 volume mixture of toluene:liquid hydrocarbon-containing material; and
“Uncalcined” material or substance is defined as a material or substance that has not been oxidized as a result of heating to a temperature of at least 350° C.

In the process of the present invention, a hydrocarbon-containing feedstock that is comprised of at least 5 wt. % n-heptane insoluble hydrocarbon-containing materials of which at least 10 wt. % are toluene insoluble hydrocarbon-containing materials is contacted with a porous silica adsorbent at a temperature of from 120° C. to 300° C. The porous silica adsorbent has a pore size distribution having a median pore size diameter of less than 180 Å as determined by mercury porosimetry. A hydrocarbon-containing product is separated from the silica adsorbent, where the hydrocarbon-containing product contains at most 50 wt. % of the toluene-insoluble materials of the hydrocarbon-containing feedstock.

The hydrocarbon-containing feedstock that is comprised of at least 5 wt. % n-heptane insoluble hydrocarbon-containing materials of which at least 10 wt. % are toluene insoluble hydrocarbon-containing materials may be a hydrocarbon-containing material, or a portion thereof, that has been treated at a temperature of at least 350° C. The hydrocarbon-containing feedstock may contain at least 10 wt. % n-heptane insoluble hydrocarbon-containing materials. The hydrocarbon-containing feedstock may be a liquid residual fraction from a thermal cracking, a hydrocracking, or a catalytic cracking process. The hydrocarbon-containing feedstock may be heavy oil stripper bottoms from an LC Fining or H-Oil process for upgrading an atmospheric residue fraction of a crude oil or a vacuum residue fraction of a crude oil.

The hydrocarbon-containing feedstock is contacted with a porous silica adsorbent to separate a hydrocarbon-containing product from a toluene insoluble compound-rich material, where the porous silica adsorbent preferentially adsorbs n-heptane insoluble, toluene insoluble hydrocarbon-containing materials from the hydrocarbon-containing feedstock and preferentially does not adsorb other components of the hydrocarbon-containing feedstock including n-heptane insoluble, toluene soluble hydrocarbon-containing materials. The porous silica adsorbent may be comprised of silica particles. The porous silica adsorbent may be a silica gel. The porous silica adsorbent has a pore size distribution, where the median pore size diameter of the pore size distribution is less than 180 Å as determined by mercury porosimetry. The porous silica adsorbent may have a pore size distribution having a median pore size diameter of from 50 Å to 150 Å. The porous silica adsorbent may not be oxidized as a result of heating the silica adsorbent to a temperature of at least 350° C. or at least 500° C.—ie. the silica adsorbent may be uncalcined. The porous silica adsorbent may have a surface area of at least 100 m²/g or at least 150 m²/g. The porous silica adsorbent may have a moisture content of from 1 wt. % to 5 wt. % water, or the porous silica adsorbent may be dry.

Referring now to FIG. 1, the hydrocarbon-containing feedstock may be contacted with the porous silica adsorbent in a contacting vessel 101 containing the adsorbent. The hydrocarbon-containing feedstock may be fed to the contacting vessel 101 through conduit 103. The contacting vessel 101 containing the porous silica adsorbent may be any conventional contacting vessel structured and arranged to facilitate contact of a liquid feed with a particulate solid. The porous silica adsorbent may be disposed within the contacting vessel in a fixed bed through which the hydrocarbon-containing feed is dispersed for contact with the silica. Alternatively the porous silica adsorbent may be disposed within the contacting vessel in an ebullating bed or a slurry bed, where the silica forms an ebullating bed or a slurry bed in liquid introduced into the contacting vessel 101.

The hydrocarbon-containing feedstock is contacted with the porous silica adsorbent at a temperature of from 120° C. to 300° C. The hydrocarbon-containing feedstock may be contacted with the porous silica adsorbent at a temperature of from 150° C. to 250° C. The hydrocarbon-containing feedstock may be heated prior to being contacted with the porous silica adsorbent, or the hydrocarbon-containing feedstock may be heated while contacting the porous silica adsorbent. In one embodiment, the contacting vessel 101 may comprise a heating element to heat the hydrocarbon-containing feedstock while the hydrocarbon-containing feedstock contacts the porous silica adsorbent.

The hydrocarbon-containing feedstock may be contacted with the porous silica adsorbent at a temperature of 120° C. to 300° C. for a period of time sufficient to adsorb at least a portion of the toluene-insoluble hydrocarbon-containing materials of the n-heptane insoluble hydrocarbon-containing materials of the hydrocarbon-containing feed on the silica adsorbent. The hydrocarbon-containing feedstock may be contacted with the porous silica adsorbent for a time period of at least 15 minutes, or at least 1 hour, or from 15 minutes to 24 hours, or from 1 hour to 6 hours to adsorb toluene-insoluble hydrocarbon-containing materials of the n-heptane insoluble hydrocarbon-containing materials of the hydrocarbon-containing feedstock on the silica adsorbent.

The volume of hydrocarbon-containing feedstock relative to the volume of porous silica adsorbent may be selected to ensure adsorption of at least a portion of the toluene insoluble hydrocarbon-containing materials of the hydrocarbon-containing feedstock onto the porous silica adsorbent. The volume of hydrocarbon-containing feedstock to the volume of porous silica adsorbent may be at most 10:1, or at most 5:1, or at most 2:1, or may be from 0.01 to 1.5, or from 0.1 to 1.

A liquid hydrocarbon-containing product may be separated from the porous silica material and from the contacting vessel 101 by removing the liquid hydrocarbon-containing product from the solid porous silica material and producing the liquid hydrocarbon-containing product from the contacting vessel through conduit 105. The liquid hydrocarbon-containing product contains at most 50 wt. % of the toluene-insoluble compounds of the n-heptane insoluble compounds of the hydrocarbon-containing feedstock. The liquid-hydrocarbon containing product may contain at most 30 wt. %, or at most 20 wt. %, of the toluene-insoluble hydrocarbon-containing compounds of the n-heptane insoluble hydrocarbon-containing compounds of the hydrocarbon-containing feedstock. The liquid hydrocarbon-containing product may retain a significant portion of the n-heptane insoluble hydrocarbon-containing compounds of the hydrocarbon-containing feedstock, where the retained n-heptane insoluble hydrocarbon-containing compounds may be soluble in toluene. The liquid hydrocarbon-containing product may contain at least 40 wt. % or at least 50 wt. % of the n-heptane insoluble hydrocarbon-containing compounds of the feedstock.

The liquid hydrocarbon-containing product may have one or more improved characteristics relative to the feedstock due to separation of the toluene-insoluble hydrocarbon-containing materials of the n-heptane insoluble hydrocarbon-containing materials from the feedstock by the adsorbent. The liquid hydrocarbon-containing product may have fewer coke precursors therein relative to the feedstock. In one embodiment of the process of the present invention, the separated liquid hydrocarbon-containing product may be thermally cracked, hydrocracked, or catalytically cracked to produce a cracked product. The liquid hydrocarbon containing-product may contain fewer compounds that induce phase instability in the liquid product. In another embodiment of the process of the present invention, the separated liquid hydrocarbon-containing product may be blended with another hydrocarbon-containing composition. The separated liquid hydrocarbon-containing product may have a dynamic viscosity that is at most 50% of the isothermic dynamic viscosity of the hydrocarbon-containing feedstock.

Referring again to FIG. 1, the porous silica adsorbent from which the liquid hydrocarbon-containing product has been separated may be washed with a solvent to separate the materials adsorbed onto the silica from the silica to regenerate the silica adsorbent. Solvent may be provided to the contacting vessel 101 through conduit 107 and may be contacted with the silica adsorbent therein. The solvent containing the compounds washed off of the silica adsorbent may be separated from the silica adsorbent, for example, by removing the solvent containing the separated compounds from the contacting vessel 101 through conduit 109. The solvent may contact the silica adsorbent for a time period sufficient to remove a substantial portion of the compounds adsorbed to the silica from the silica and thereby regenerate the silica. The time required for the solvent to remove a substantial portion of the compounds adsorbed to the silica from the silica may be dependent on the solvent and the compounds to be removed from the silica, however, the time required may range from 30 minutes to 4 days. One of ordinary skill in the art may determine the appropriate time to contact the solvent with the silica adsorbent to remove the compounds from the silica by routine experimentation.

The solvent utilized to wash the porous silica adsorbent to remove the compounds adsorbed onto the silica is a solvent in which the toluene-insoluble hydrocarbon-containing materials from the n-heptane insoluble hydrocarbon-containing materials of the feedstock are soluble. The solvent utilized to wash the silica adsorbent to remove the materials adsorbed onto the silica may be a relatively polar solvent. The solvent may be selected from the group consisting of toluene:ethanol (85:15 vol %), ethanol:water (95:5 vol.%); methylene chloride; methylene chloride:methanol (79:21 vol %); methylene chloride:acetone (79:21 vol %); carbon disulfide; dimethyl sulfide; N-methyl-2-pyrrolidone (NMP); pyridine; diglyme; furfural; dimethylformamide (DMF); dimethylsulfoxide; 1,2-dichlorobenzene; acetonitrile; ethylene glycol:methylene chloride (50:50 vol.%); 2-fluorophenol; acetylacetone; tetrahydrofuran (THF); benzonitrile; and mixtures thereof. In a preferred embodiment, the solvent may be pyridine.

The solvent containing the toluene-insoluble hydrocarbon-containing materials may be separated and recovered from such materials. The solvent containing the toluene-insoluble hydrocarbon-containing materials may be provided to a separator 111, which may be a distillation column or a flash separator. The solvent may be separated from the toluene-insoluble hydrocarbon-materials by distillation or by flashing, and may be removed from the separator 111 as an overhead gas stream 113. The gas stream 113 may be cooled in a heat exchanger 115 to recover liquid solvent, which may be fed back to the contacting vessel 111 to separate further toluene-insoluble hydrocarbon-containing materials from the silica adsorbent.

The toluene-insoluble hydrocarbon-containing materials may be recovered from the separator 111 as a bottoms stream 117. The toluene-insoluble hydrocarbon-containing materials may be provided to a coker to recover light hydrocarbons and produce petroleum coke.

Valves 119 and 121 may control the flow of the hydrocarbon-containing feedstock and the solvent into the contacting vessel 101. The hydrocarbon-containing feedstock and the solvent may be fed in alternating slugs into the contacting vessel, where the silica adsorbent first adsorbs toluene insoluble hydrocarbon-containing materials from the hydrocarbon-containing feedstock, then the solvent washes the toluene insoluble hydrocarbon-containing materials from the silica adsorbent. Valves 123 and 125 may control the flow of the hydrocarbon-containing product and the mixture of solvent and toluene insoluble hydrocarbon-containing materials from the contacting vessel 101.

In another embodiment, not shown, the porous silica adsorbent may be located in two or more separate contacting vessels. Hydrocarbon-containing feedstock may be fed to one of the contacting vessels to separate the toluene insoluble hydrocarbon-containing materials and to produce the hydrocarbon-containing product while the solvent is fed to another contacting vessel to wash toluene insoluble hydrocarbon-containing materials from the adsorbent. After a period of time, the feeds to the contacting vessels may be switched to provide the hydrocarbon-containing feedstock to the washed porous silica adsorbent and to provide the solvent to the adsorbent containing toluene insoluble hydrocarbon-containing materials separated from the hydrocarbon-containing feedstock. The feeds to the contacting vessels may be alternated as desired to maintain a continuous separation of the toluene insoluble hydrocarbon-containing materials from the hydrocarbon-containing feedstock.

To facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are given. In no way should the following examples be read to limit, or define, the scope of the invention.

Example 1

The selectivity of 3 adsorption candidates for adsorbing toluene insoluble, methylene chloride soluble compounds relative to n-heptane insoluble, cyclohexane soluble compounds from a cracked vacuum residue bottoms feedstock was measured. As described in detail in U.S. Pat. No. 8,367,425, the ratio of the n-heptane insoluble, cyclohexane soluble compounds to toluene insoluble, methylene chloride soluble compounds in the feedstock and in the product resulting from separation of the non-adsorbed hydrocarbon liquid from the adsorption media provides a coking index that is predictive of the feedstock and product to form coke when subject to further processing at temperatures of 350° C. or greater.

Grace P543 silica gel, spent residue hydrocracking catalyst, and glass beads were selected as adsorption media. 25 ml of each adsorption media sample was dried in a vacuum oven at 105-110° C. for 18-24 hours under dynamic vacuum, then cooled to ambient temperature while still under vacuum. The dried Grace P543 silica gel had a pore size distribution with a median pore diameter of 86.0 Å as determined by mercury porosimetry, and a surface area of 365 m²/g/. After cooling, the samples were placed under argon by backfilling the vacuum oven with argon.

Each adsorption media sample was then placed in its own 50 ml stainless steel batch reactor along with 25 ml of the cracked vacuum residue bottoms feedstock to provide a 1:1 volume ratio of the adsorption media sample to the feedstock. Characteristics of the vacuum residue bottoms feedstock are provided in Table 1 below.

TABLE 1
Cracked Vacuum Residue Bottoms
Hydrogen, % w            9.397
Carbon, % w              87.08
Nitrogen, % w            0.8762
Sulfur, % w              2.28
Oxygen, % w              n.d.
Vanadium, ppmw           98
Nickel, ppmw             70
Density, g/ml            1.0365
Viscosity@ 100° C., cS   174
C5-asphaltenes, % w      16.0
C7-asphaltenes, % w      11.7
Microcarbon Residue, % w 20.3

A separate control reactor was filled with 50 ml of the feedstock only, with no adsorption media sample therein. The reactors were sealed and then mechanically agitated in a heated fluidized sand bed at a temperature of 150° C. for four hours. The reactors were then cooled with a fan to room temperature, reaching room temperature in 20-25 minutes. The reactors were then opened, and liquid product and solid sorbent were separated over a 60 mesh screen, except for the control which contained only liquid product. This experiment was repeated at selected temperatures of 200° C., 250° C. and 300° C. for each adsorbent media sample.

The relative quantities of all n-heptane insoluble hydrocarbon-containing compounds of the samples and the relative quantities of the toluene insoluble, methylene chloride soluble compounds and n-heptane insoluble, cyclohexane soluble compounds of the samples were determined by solvent separation in a packed polytetrafluoroethylene column in accordance with the Four Solvent Separation Conditions analysis as set forth in U.S. Pat. No. 8,367,425 using methylene chloride as the fourth solvent, where the detector utilized was an evaporative light scattering detector (ELSD).

The percent change of all n-heptane insoluble hydrocarbon-containing compounds in each sample relative to the cracked vacuum residue bottoms feedstock is shown in Table 2.

TABLE 2
% Change of n-heptane insoluble hydrocarbon-containing compounds
relative to cracked vacuum residue bottoms feedstock
			Dried P543
			Silica Gel	Spent Residue
			(median pore	Hydrocracking
	Control	Glass Beads	diameter 86 Å)	Catalyst
150° C.	0	−1	−46	8
200° C.	−2	−4	−54	−1
250° C.	0	−1	−53	9
300° C.	−5	−4	−50	10

The percent change of toluene insoluble hydrocarbon-containing compounds that are soluble in methylene chloride in each sample relative to toluene insoluble hydrocarbon-containing compounds in the feedstock is shown in Table 3.

TABLE 3
% Change of toluene insoluble and methylene chloride
soluble hydrocarbon-containing compounds relative
to toluene insoluble hydrocarbon-containing compounds
in cracked vacuum residue bottoms feedstock
			Dried P543
			Silica Gel	Spent Residue
			(median pore	Hydrocracking
	Control	Glass Beads	diameter 86 Å)	Catalyst
150° C.	0	−13	−81	3
200° C.	−2	−14	−88	−10
250° C.	−5	−16	−86	2
300° C.	−12	−20	−80	−16

The data shown in Tables 2 and 3 indicate that the dried silica gel was effective at adsorbing n-heptane insoluble hydrocarbon-containing compounds from the feedstock, and more selectively adsorbed toluene insoluble/methylene chloride soluble hydrocarbon-containing compounds relative to other n-heptane insoluble hydrocarbon-containing compounds, removing at least 50% of such compounds at 200° C.

A coking index was determined for each adsorbent media sample at each of the selected temperatures, where the coking index was determined by calculating the ratio of the area of a cyclohexane ELSD peak (2d peak) to the area of a methylene chloride ELSD peak (4^th peak) [(C₆H₁₂)/(CH₂C₁₂)]. The coking index is predictive of the stability of a sample against coke formation or flocculation, as discussed in detail in U.S. Pat. No. 8,367,425 and U.S. Pat. No. 6,773,921—where a coking index of >1 indicates a stable oil sample. The calculated coking index for the samples is provided in Table 4.

TABLE 4
Coking Index
			Dried P543
			Silica Gel	Spent Residue
			(median pore	Hydrocracking
	Control	Glass Beads	diameter 86 Å)	Catalyst
150° C.	0.53	0.65	2.17	0.65
200° C.	0.46	0.50	2.67	0.61
250° C.	0.24	0.30	1.22	0.31
300° C.	0.24	0.31	0.91	0.38

As shown in Table 2, the products from the cracked vacuum residue bottoms contacted with the dried silica gel at a temperature of from 150° C. to 300° C., and particularly at a temperature of from 150° C. to 250° C., were significantly stabilized relative to a cracked vacuum residue bottoms feedstock control and the other adsorbent samples as measured by the coking index.

Example 2

The adsorption capacity of a number of adsorption candidates for adsorbing toluene insoluble, methylene chloride soluble hydrocarbon-containing compounds from a cracked vacuum residue bottoms feedstock was measured. The adsorption capacity of the adsorption candidates was measured at 200° C. The characteristics of the cracked vacuum residue bottoms feedstock are shown in Table 1 above. The procedure utilized to measure the adsorption capacity of each sample is the same procedure as set forth in Example 1. The percent change of toluene insoluble, methylene chloride soluble hydrocarbon-containing compounds relative to toluene insoluble compounds in the cracked vacuum residue bottoms feedstock are shown in Table 5.

TABLE 5
% Change of toluene insoluble/methylene soluble
hydrocarbon-containing compounds relative to
cracked vacuum residue bottoms feedstock
                                 Toluene insoluble/methylene
                                 chloride soluble compounds
                                 (% change relative to toluene
                                 insoluble compounds in
                                 feedstock)
Control                          −2
Grace P543 Silica Gel (dried) (median −88
pore diameter = 86 Å)
Spent Residue Hydrocracking Catalyst −10
Grace P543 Silica Gel (undried)  −86
Small Glass Beads                −14
Sorbead H                        −21
Active Carbon (Chemviron)        3
Steel Shot                       3
Alumina Dynocel 628              −61
Alumina WR-354A                  −52
Alumina SAS 451                  −52
Active Carbon (Norit)            19
Iron Silicate Powder             −73
Stainless Steel Powder           −27
Alumina Extrudate KL5890         −59
Alumina Extrudate AX300          −38
Alumina Extrudate AX430          −75
Alumina Extrudate KL5860         −70
Petroleum Coke                   −22
Toluene Extracted Oil Sand       −30
Heli-pak, Size A                 3
Nickel Powder                    −3
Torrified Poplar Wood            31

As shown in Table 3, silica gel, both dried and undried, was highly effective for selectively separating toluene insoluble/methylene chloride soluble hydrocarbon-containing compounds from the feedstock.

Example 3

The effect of pore size on n-heptane insoluble hydrocarbon-containing compound adsorption for silica substrates was examined. The n-heptane insoluble compound adsorption and the toluene insoluble/methylene chloride soluble compound adsorption of an uncalcined silica gel, dried at a temperature of 100° C. under vacuum for 18-24 hours, and silica gels calcined at temperatures of 500° C., 600° C., 700° C., 800° C., 900° C., and 1000° C. were measured at 200° C. according to the procedure set forth in Example 1. The surface area, pore volume, and median pore diameter of the samples were also measured. The results are shown in Table 6.

	TABLE 6
					Toluene
				n-heptane	insoluble/methylene
	Surface		Median Pore	insolubles (%	chloride soluble (%
	Area	Pore Volume	Diameter (Å)	change from	change relative to
	(m2/g) Hg	(cc/g) Hg	Hg	feedstock)	toluene insolubles)
Grace P543	365	1.060	86.0	−54	−88
Silica Gel
Silica calcined	346	1.318	205.3	−28	−53
at 500° C.
Silica calcined	337	1.296	208.6	−28	−58
at 600° C.
Silica calcined	326	1.277	212.3	−28	−56
at 700° C.
Silica calcined	268	1.193	229.2	−25	−52
at 800° C.
Silica calcined	169	1.080	286.9	−23	−55
at 900° C.
Silica calcined	84	0.645	330.2	−15	−42
at 1000° C.

As shown in Table 3, uncalcined silica gel having a relatively small median pore diameter was significantly more effective at adsorbing and removing toluene insoluble n-heptane insoluble hydrocarbon-containing compounds from the feedstock than calcined silicas having a median pore diameter of greater than 200 Å.

Example 4

The effect on viscosity induced by contacting cracked vacuum residue bottoms with a silica gel adsorbent having a median pore diameter of 86 Å was determined. The dynamic shear viscosity of the cracked vacuum residue bottoms, the control produced by heating the cracked vacuum residue bottoms at 200° C. for 4 hours in Example 1, and product produced by contacting the cracked vacuum residue bottoms with Grace P543 silica gel at 200° C. in Example 1 was measured at 60° C. The results are set forth in Table 7.

	TABLE 7
	Temperature	Dynamic Shear
	(° C.)	Viscosity (Pa-s)
Cracked vacuum residue	60	4.07
bottoms
Control (200° C.-4 hrs)	60	4.04
Grace P543 Silica Gel contact	60	1.45
product (200° C.-4 hrs)

As shown in Table 7, the product produced by contacting the feedstock with silica gel at 200° C. had significantly reduced dynamic shear viscosity relative to a control treated at the same temperature and relative to the feedstock.

The present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. While systems and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from a to b,” or, equivalently, “from a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Whenever a numerical range having a specific lower limit only, a specific upper limit only, or a specific upper limit and a specific lower limit is disclosed, the range also includes any numerical value “about” the specified lower limit and/or the specified upper limit. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an”, as used in the claims, are defined herein to mean one or more than one of the element that it introduces.

Claims

1. A process for separating toluene insoluble compounds from a hydrocarbon-containing feedstock, comprising:

providing a hydrocarbon-containing feedstock comprising at least 5 wt. % n-heptane insoluble hydrocarbon-containing materials, wherein at least 10 wt. % of the n-heptane insoluble hydrocarbon-containing materials are toluene insoluble hydrocarbon-containing materials, and wherein n-heptane insoluble hydrocarbon-containing materials are hydrocarbon-containing materials that precipitate from a liquid hydrocarbon-containing material in a 40:1 volume mixture of n-heptane:liquid hydrocarbon material at 25° C. and toluene insoluble hydrocarbon-containing materials are materials that precipitate from a liquid hydrocarbon-containing material in a 40:1 volume mixture of toluene:liquid hydrocarbon material at 25° C.;

contacting the hydrocarbon-containing feedstock with a porous silica adsorbent at a temperature of from 120° C. to 300° C., wherein the silica of the silica adsorbent has a pore size distribution having a median pore size diameter of less than 180 Å as determined by mercury porosimetry;

separating a hydrocarbon-containing product from the silica adsorbent, wherein the hydrocarbon-containing product contains at most 50% of the toluene-insoluble hydrocarbon-containing compounds of the hydrocarbon-containing feedstock.

2. The process of claim 1 wherein the hydrocarbon-containing product contains at least 50% less, or at least 70% less, or at least 80% less of the toluene insoluble compounds of the n-heptane insoluble compounds relative to the hydrocarbon-containing feedstock.

3. The process of claim 1 wherein the silica adsorbent is a silica gel that has not been heated to a temperature of at least 500° C.

4. The process of claim 1 wherein the pore size distribution of the silica of the silica adsorbent has a median pore size diameter of from 50 Å to 150 Å.

5. The process of claim 1 wherein the silica of the silica adsorbent has a surface area of at least 100 m2/g.

6. The process of claim 1 wherein the silica adsorbent has a moisture content of from 2 wt. % to 5 wt. % water.

7. The process of claim 1 wherein the hydrocarbon-containing feedstock and the silica adsorbent are contacted at a temperature of from 150° C. to 250° C.

8. The process of claim 1 further comprising the steps of:

contacting the silica adsorbent with a solvent effective to solvate the toluene insoluble compounds after separating the hydrocarbon-containing product from the silica adsorbent; and

separating the solvent and at least a portion of the toluene insoluble compounds from the silica adsorbent.

9. The process of claim 8 wherein the solvent is selected from the group consisting of pyridine, n-pyrrolidone, dichloromethane, methanol, and a mixtures thereof.

10. The process of claim 1 further comprising cracking the separated hydrocarbon-containing product.

11. The process of claim 1 further comprising the step of blending the separated hydrocarbon-containing product with a hydrocarbon-containing liquid.

12. The process of claim 11 wherein the hydrocarbon-containing liquid with which the separated hydrocarbon-containing product is blended is comprised of at least 10 wt. % n-heptane insoluble compounds.

13. The process of claim 1 wherein the contacting temperature and time are controlled such that the hydrocarbon-containing product has a dynamic viscosity at 25° C. that is at most 50% of the dynamic viscosity of the hydrocarbon-containing feed at 25° C.