CN111655823A

CN111655823A - Process and apparatus for deasphalting and asphalt conversion

Info

Publication number: CN111655823A
Application number: CN201980010250.4A
Authority: CN
Inventors: 贾甘纳坦·戈文达坎南; 汉斯·G·列斐伏尔
Original assignee: UOP LLC
Current assignee: Honeywell UOP LLC
Priority date: 2018-01-31
Filing date: 2019-01-30
Publication date: 2020-09-11
Also published as: EP3746524A4; US20190233746A1; WO2019152510A1; EP3746524A1

Abstract

Solvent Deasphalting (SDA) is disclosed for the continuous extraction of deasphalted oil from heavier hydrocarbons. The pitch stream from solvent deasphalting is calcined to recover volatile hydrocarbon vapor products and calcined solids. The hydrocarbon vapors may be fractionated to recover valuable transport distance fuel products. The bitumen stream may first be fed to a fractionation column prior to calcination.

Description

Process and apparatus for deasphalting and asphalt conversion

Technical Field

The art relates to methods and apparatus for separating heavy hydrocarbon feeds into lighter hydrocarbon streams by solvent deasphalting.

Background

As reserves of conventional crude oil decline, heavy oil must be upgraded to meet market demand. Crude oil is typically first processed in an atmospheric crude distillation tower to provide fuel products, including naphtha, kerosene, and diesel. The atmospheric crude distillation residue bottoms stream is typically taken to a vacuum distillation column to obtain Vacuum Gas Oil (VGO), which may be a feed to an FCC unit or hydrocracking unit and Vacuum Residue (VR).

Solvent Deasphalting (SDA) generally refers to a refining process that uses extraction in the presence of a solvent to upgrade a hydrocarbon fraction. The hydrocarbon fraction is typically obtained from the distillation of crude oil and includes hydrocarbon residue or gas oil from atmospheric or vacuum column distillation. SDA permits the actual recovery of higher quality oil at relatively low temperatures without cracking or degrading the heavy hydrocarbons. SDA separates hydrocarbons based on their solubility in liquid solvents rather than their volatility in distillation. The lower molecular weight components and most of the aliphatic components are preferentially extracted. The least soluble species are high molecular weight and are primarily aromatic and polar components. This allows deasphalted oil (DAO) to extract light and aliphatic oils, and bitumen raffinates are also known as bitumen, heavy oil, and aromatic oil. Suitable solvents for the SDA include, for example, propane and higher molecular weight paraffin waxes, such as butane and pentane. The bitumen stream generally contains metal compounds as well as high molecular weight hydrocarbons.

SDA typically recovers no more than 40 wt.% of the product. Therefore, further recovery is highly desirable in SDA to make it valuable. Once the SDA pitch stream is stripped to remove residual solvent, a cost-effective outlet for the stripped pitch is found to be challenging for the refiner. The use of stripped bitumen to prepare bitumen (asphal) is not always a viable option. Burning the stripped bitumen along with the necessary gas treatment is a very expensive solution. Micronization of the stripped bitumen is also an expensive solution and micronized bitumen may re-agglomerate during transport.

There is a continuing need to improve the conversion and disposal of bitumen from deasphalting processes and equipment to increase recovery.

Disclosure of Invention

A process and apparatus for improving the recovery of valuable hydrocarbons from solvent deasphalting has been discovered. The SDA pitch stream is delivered to a calciner that gasifies the smaller hydrocarbons and thermally cracks the larger hydrocarbons, producing a vapor product stream while leaving a stream of calcined solids. The vapor product stream may be separated in the same separator to which the bitumen stream is fed for heating. The separator can recover at least one hydrocarbon product stream.

Definition of

As used herein, the term "communicate" means operatively permitting a flow of a substance between enumerated components.

As used herein, the term "downstream communication" means that at least a portion of a substance flowing in the downstream communication to a component is capable of operably flowing from the component with which it is in communication.

As used herein, the term "upstream communication" means that at least a portion of a substance flowing from a component in upstream communication is capable of operably flowing to the component with which it is in communication.

The term "in direct communication" means that the stream from an upstream component enters a downstream component without passing through a fractionation or conversion unit and without undergoing a compositional change due to physical fractionation or chemical conversion.

The term "indirect communication" means that a stream from an upstream component, after passing through a fractionation or conversion unit, enters a downstream component and undergoes a compositional change due to physical fractionation and/or chemical conversion.

As used herein, the term "rich component stream" means that the rich stream exiting the separator vessel has a greater concentration of components than the feed to the separator vessel.

As used herein, the term "lean component stream" means that the lean stream exiting the separator vessel has a lower concentration of components than the feed to the separator vessel.

The term "column" means one or more distillation columns for separating the components of one or more different volatile substances. Unless otherwise specified, each column includes a condenser at the top of the column for condensing a portion of the top stream and refluxing it back to the top of the column, and a reboiler at the bottom of the column for vaporizing a portion of the bottom stream and returning it to the bottom of the column. The feed to the column may be preheated. The top pressure is the pressure of the overhead vapor at the vapor outlet of the column. The bottom temperature is the liquid bottom outlet temperature. Overhead and bottoms lines refer to the net lines to the column from any column downstream of reflux or reboiling. The stripper column may omit a reboiler at the bottom of the column and instead provide the heating requirements and separation power for the liquefied inert medium (such as steam). The stripper is typically fed from a top tray and the main product is withdrawn from the bottom.

As used herein, the term "true boiling point" (TBP) means a test method corresponding to ASTM D-2892 for determining the boiling point of a material used to produce standardized masses of liquefied gases, fractions and residues from which analytical data can be obtained, and determining the yields of such fractions by both mass and volume from which a plot of distillation temperature versus mass% is obtained in a column having a reflux ratio of 5:1 using fifteen theoretical plates.

As used herein, the term "initial boiling point" (IBP) means the temperature at which a sample begins to boil, as determined using ASTM D-7169 or TBP, as the case may be.

As used herein, the term "T5", "T70", or "T95" means the temperature at which a 5, 70, or 95 mass percent (as the case may be) sample boils, as derived using astm d-7169 or TBP (as the case may be).

As used herein, the term "separator" means a vessel having an inlet and at least one overhead vapor outlet and one bottom liquid outlet, and may also have an outlet for an aqueous stream from a storage tank (boot). The flash tank is a separator that may be in downstream communication with the separator, which may operate at a higher pressure.

Drawings

FIG. 1 is a schematic diagram of a method and apparatus.

Fig. 2 is a schematic diagram of an alternative embodiment of the method and apparatus of fig. 1.

Detailed Description

Embodiments of the invention relate to the use of SDA to produce a heavy hydrocarbon feedstock for upgrading. According to one embodiment, for example, a heavy hydrocarbon feedstock comprises a residual oil such as an atmospheric resid having an IBP of at least 232 ℃ (450 ° f), 288 ℃ (550 ° f) and 392 ℃ (700 ° f), a T5 generally not exceeding 343 ℃ (650 ° f), and a T95 obtained from the bottom of an atmospheric crude distillation column between 510 ℃ (950 ° f) and 700 ℃ (1292 ° f). Another heavy hydrocarbon feedstock is a vacuum residuum having an IBP of at least 500 ℃ (932 ° f). Tar, bitumen, kerosene and shale oil may be additional heavy hydrocarbon feedstocks. Other asphaltene-containing materials such as whole petroleum crude oil or topped petroleum crude oil (including heavy crude oil) may also be used as a component for processing by SDA. In addition to asphaltenes, these other possible components of heavy hydrocarbon feedstocks, as well as other components, generally contain significant metal contaminants such as nickel, iron, and vanadium, high levels of organic sulfur and nitrogen compounds, and high conradson carbon residue. The metal content of such components may be, for example, 100ppm to 1,000ppm (by weight), the total sulfur content may be in the range of 1% to 7% (by weight), and the API gravity may be in the range of-5 ° to 35 °. The conradson carbon residue of such components is generally at least 5%, and typically 10% to 30% (by weight).

As shown in fig. 1, a method and apparatus 10 for extracting lighter hydrocarbons from heavier hydrocarbons is illustrated by a solvent deasphalting unit 12. The heavy hydrocarbon feedstream in the heavy feed line 20 can be passed to the solvent deasphalting unit 12. In the SDA process, the heavy hydrocarbon feed stream in the heavy feed line 20 is pumped and blended with the mixed solvent stream in the mixed solvent line 22 before entering the extraction column 24. An additional solvent stream, for example in an additional solvent line 28, may be added to the lower end of extraction column 24 through an additional solvent inlet 28 i. An extractor inlet line 26 in downstream communication with the heavy feed line 20 and the mixed solvent line 22 may deliver the mixed feed to the extraction column 24, and thus to the mixed inlet 26i, through the extractor inlet line. The solvent (typically propane or butane or a mixture thereof) dissolves the lighter aliphatic hydrocarbon materials in the heavy hydrocarbon feed. Trays or packing may be utilized above each solvent inlet 26i, 28i in the extraction column 24 to separate asphaltenic compounds from the dissolved deasphalted oil rising from the column. The DAO stream is extracted from the heavy hydrocarbon feedstream and exits the extractor 24 in a DAO line 30 extending from the top of the extractor 24. The heavier aromatic and polar components in the feed are insoluble in the solvent and precipitate out as asphaltenes or bitumen streams in a bitumen line 32 extending from the bottom of the extraction column 24. Extraction column 24 can typically operate at 70 ℃ (158 ° f) to 204 ℃ (400 ° f) and 3.8MPa (550psia) to 5.5MPa (800 psia).

The DAO stream in DAO line 30 has a greater concentration of aliphatics than the heavy hydrocarbon feedstream in heavy feed line 20. The DAO stream is heated to the supercritical temperature of the solvent by indirect heat exchange with the separated solvent stream in a heat exchanger and a separate solvent line 36 in a subsequent heater or additional heat exchanger, and is fed to the DAO separator column 40 through DAO inlet 30 i. The supercritical heated solvent is separated from the DAO in a DAO separator column 40, which DAO separator column 40 is in downstream communication with a DAO line 30 from the top of the extraction column 24. The DAO separator column 40 may be in downstream communication with the DAO line 30 of the extraction column 24. The separated solvent stream exits the DAO separator column 40 in a separator solvent line 36 extending from the top of the DAO separator column 40. Packing or trays in the DAO separator column above DAO inlet 30i may facilitate separation. The separated DAO stream exits in a separated DAO line 42 extending from the bottom of the DAO separator column 40. The solvent recycle stream is condensed by indirect heat exchange in a heat exchanger with the DAO stream in DAO line 30 and a condenser. The DAO separator column 40 will typically operate at 177 ℃ (350 ° f) to 287 ℃ (550 ° f) and 3.8MPa (550psia) to 5.5MPa (800 psia).

The bitumen stream in bitumen line 32 contains a greater concentration of aromatic compounds than the heavy feed stream in heavy feed line 20. The bitumen stream in bitumen line 32 is heated in a heater or by heat exchange and fed to bitumen stripper column 50 through a bitumen inlet 32i above the inlet of inert gas line 52 and in downstream communication with the bitumen line 32 to produce a solvent recovery stream in a solvent recovery line 54 extending from the top of bitumen stripper column 50 and a stripped bitumen stream lean in solvent in a stripped bitumen line 56 extending from the bottom of bitumen stripper column 50. An inert gas, such as steam from line 52, distributed below bitumen inlet 32i may be used as stripping fluid in bitumen stripper column 50. The bitumen stripper column 50 will typically operate at 204 ℃ (400 ° F) to 299 ℃ (570 ° F) and 344kPa (50psia) to 1,034kPa (150 psia).

Lean solvent DAO vapor exits DAO separator column 40 in separated DAO line 42 and enters DAO stripper column 60 through DAO stripper inlet 42i in downstream communication with separated DAO line 42. DAO stripper column 60 also separates a stripper solvent stream in stripper solvent line 64 extending from the top of the DAO stripper column from a deasphalted stream in DAO product line 66 by: the solvent is stripped from the DAO at low pressure using inert gas from line 62 having an inlet below DAO stripper inlet 42 i. Steam in line 62 may be used as stripping fluid in the DAO stripper column 60. The DAO stripper column 60 will typically operate at 149 ℃ (300 ° f) to 260 ℃ (500 ° f) and 344kPa (50psia) to 1,034kPa (150 psia). Additional solvent recovery stream remains in stripper solvent line 64 and combines with the recovered solvent in solvent recovery line 54, and is then condensed by a cooler and received in solvent reservoir 68, which solvent reservoir 68 may include a reservoir for removing water. Recovered solvent is pumped from reservoir 68 through solvent recycle line 70 as needed to replenish separated solvent in separated solvent line 36 to facilitate extraction in extraction column 24. Make-up solvent may be added at make-up line 72. Substantially solvent-free DAO is provided in line 66 comprising from 30 wt% to 50 wt% of the heavy feed in heavy feed line 20.

The stripped pitch stream in the stripped pitch line 56 may be calcined in the calciner 80 to produce more hydrocarbon product. In the calciner 80, the smaller hydrocarbons are vaporized and the larger hydrocarbons are thermally cracked to produce a volatile vapor product stream in a vapor product line 82 and leave a stream of calcined solids in a calcined solids line 84. A portion of the calcined solids may be recycled to the inlet of the calciner 80 in a recycle line 86.

The calciner 80 may comprise an elongate horizontally oriented vessel having a width greater than its height. The calciner 80 includes an inlet end 81 that receives the pitch stream. The calciner 80 may be in downstream communication with the pitch line 32 and the stripped pitch line 56. The calciner 80 may have rotating equipment, such as rotating drums or baffles or paddles, which mechanically move the pitch stream generally horizontally from the inlet end 81 to the outlet end 83 under heat. Calcined solids line 84 can extend from at or near outlet end 83. The vapor product stream may exit at or near the top 85 of the calciner in a vapor product line 82, which vapor product line 82 may extend from the top of the calciner 80. The calciner 80 may have a generally cylindrical configuration and may be tapered or inclined from the inlet end 81 toward the outlet end 83 to allow gravity to assist the stripped pitch stream to move from the inlet end to the outlet end.

The calciner 80 may comprise a rotary calciner, a fired rotary calciner, or other substantially similar equipment. The fired calciner is preferably fired indirectly. A jacket 87 surrounding the calciner 80 may receive a hydrocarbon stream in a fuel line 88 that is combusted to indirectly heat the calciner 80. The atmosphere in the calciner 80 is inert, such as under nitrogen, preferably an oxygen-free nitrogen atmosphere, but it may be any other inert non-oxidizing atmosphere or under vacuum. The calcination may be conducted at a temperature of 450 ℃ (842 ° f) to 649 ℃ (1200 ° f), preferably 500 ℃ (932 ° f) to 600 ℃ (1112 ° f), and a pressure of 4kPa (0.6psia) to 344kPa (50psia), which may be maintained for a sufficient residence time to produce a calcined solid in a calcined solid line 84 extending from or in communication with the outlet end 83 and a hot volatile vapor product stream in the vapor product line 82. The calcined solid has the composition of petroleum coke and can be disposed of, used as a fuel, further processed to recover metals, or used as a fuel in cement production, or used as a material for carbon, carbon black, or metallurgical coke production.

The volatile hydrocarbon product stream in vapor product line 82 can be fed to separator 140 to separate at least one hydrocarbon product stream. The separator 140 may be in downstream communication with the calciner 80. The separator 140 can be a fractionation column 140 that fractionates the vapor product stream to provide a plurality of product streams including an exhaust stream in an exhaust line 142, a naphtha stream in a clean naphtha line 144, a diesel stream in a diesel line 146, and a gas oil stream in a gas oil line 148. A portion of the gas oil stream in gas oil line 148 may be cooled and pumped back around the column 140 and sprayed over the rising vapor to flush entrained heavier hydrocarbons into the liquid stream in the bottom of the column. An inert gas, such as steam from inert gas line 91, may be used to provide heat and stripping gas to the fractionation column 140. An overhead stream may be taken from the overhead line of the fractionation column 140, condensed and separated in a receiver to provide an off-gas stream in an off-gas line 142 and a net naphtha stream in a net naphtha line 144 and returned to the column.

In one aspect, the stripped pitch stream in the stripped pitch line 56 can be fed to the separator 140 and then to the calciner 80. The stripped pitch stream may cool the bottom of the separator 140, particularly when the separator is a fractionation column, to prevent coking of hydrocarbons entering the bottom of the column at high temperatures. In separator 140, the stripped pitch stream will be heated by absorbing heat from the hot mass in the column to preheat the stripped pitch stream. The preheated stripped pitch stream may exit the bottom of the separator 140 in a bottom line 150 and feed the calciner 80 at the inlet end 81. The calciner 80 may be in downstream communication with the bottom line 150 of the separator 140. When the separator is a fractionation column, it can be operated at a top pressure of 7kPa (g) (1psig) to 345kPa (g) (50psig) and a bottom temperature of 260 ℃ (500 ° F) to 399 ℃ (750 ° F).

Fig. 2 shows an alternative embodiment of the process and apparatus 10' of fig. 1 having a second stage 14 of solvent deasphalting. Elements in fig. 2 having the same configuration as in fig. 1 will have the same reference numerals as in fig. 1. Elements in fig. 2 that have a different configuration than the corresponding elements in fig. 1 will have the same reference numeral but be indicated with a prime ('). Elements mentioned in fig. 2 in the first stage 12' of solvent deasphalting having the same configuration as the corresponding elements in fig. 1 will have the same reference numerals but will be started as first hereinafter to distinguish them from the second such elements in the second stage 14 of solvent deasphalting. The configuration and operation of the embodiment of fig. 2 is similar to that of fig. 1, with the exception noted below.

The first stripped asphalt stream lean in solvent in stripped asphalt line 56', including asphaltenes in the first asphalt stream in first asphalt line 32, can be transported from the first stage of solvent deasphalting 12' to the second stage of solvent deasphalting 14. In the SDA method and apparatus 10', the solvent-lean first stripped pitch stream in the first stripped pitch line 56' is pumped and blended with the second mixed solvent stream in the second mixed solvent line 82 before entering the second extraction column 84. An additional second solvent stream, such as in an additional second solvent line 88, can be added to the lower end of the second extraction column 84 through an additional solvent inlet 88 i. A second extraction inlet line 86 in downstream communication with the first stripped pitch line 56' and the first pitch line 32 and the second mixed solvent line 82 may deliver the mixed feed streams together to the second extraction column 84 and to a second mixed inlet 86 i. A second solvent heavier than the first solvent (typically butane or pentane or a mixture thereof) dissolves aliphatic and lighter hydrocarbon materials in the first bitumen stream to provide a second bitumen stream in a second bitumen line 92 that is heavier than the first bitumen stream in the first bitumen line 32. Trays or packing may be utilized in the second extraction column 84 above each solvent inlet 86i, 88i to separate asphaltic material from dissolved deasphalted oil rising in the column. A second DAO stream is extracted from the first pitch stream and exits the second extraction column 84 in a second DAO line 90 extending from the overhead of the second extraction column 84. The heavier and aromatic portions of the bitumen stream are insoluble in the heavier solvent and precipitate out as a second asphaltene or bitumen stream in a second bitumen line 92 extending from the bottom of the second extraction column 84. The second extraction column 84 can typically operate at 93 ℃ (200 ° f) to 204 ℃ (400 ° f) and 3.8MPa (550psia) to 5.5MPa (800 psia).

The second DAO stream in the second DAO line 90 has a greater concentration of aliphatic compounds than the first pitch stream in the first stripped pitch line 56'. The second DAO stream is heated to the supercritical temperature of the second solvent by indirect heat exchange with the second separated solvent stream in the second separated solvent line 96 in a heat exchanger and in a subsequent heater or additional heat exchanger, and is fed to the second DAO separator column 100 through a second DAO inlet 90 i. The supercritical heated solvent is separated from the DAO in a second DAO separator column 100, the second DAO separator column 100 being in downstream communication with the second DAO line 90 of the second extraction column 84. The second DAO separator column 100 can be in downstream communication with the second DAO line 90 of the second extraction column 84. The second separated solvent stream exits the second DAO separator column 100 in a second separator solvent line 96 extending from the top of the second DAO separator column 100. Packing or trays in the second DAO separator column above the second DAO inlet 90i can facilitate separation. The second separated DAO stream exits in a second separated DAO line 102 extending from the bottom of the second DAO separator column 100. The second separated solvent stream in the second separator solvent line 96 is condensed by indirect heat exchange in a heat exchanger with the second DAO stream in the second DAO line 90 and a condenser. The DAO separator column 100 will typically operate at 177 ℃ (350 ° f) to 287 ℃ (550 ° f) and 3.8MPa (550psia) to 5.5MPa (800 psia).

Second lean solvent DAO vapor exits second DAO separator column 100 in a second separated DAO line and enters second DAO stripper column 120 through a second DAO stripper inlet 102i in downstream communication with second separated DAO line 102. Second DAO stripper column 120 further separates a second stripper solvent stream in a second stripper solvent line 124 extending from the top of the DAO stripper column from a second deasphalted stream in a second deasphalted line 126 extending from the bottom of the second DAO stripper column, stripping solvent from the DAO component at low pressure using inert gas from line 122 having an inlet below DAO stripper inlet 102 i. Steam in line 122 may be used as stripping fluid in the second DAO stripper column 120. The second DAO stripper column 120 will typically operate at 149 ℃ (300 ° f) to 260 ℃ (500 ° f) and 344kPa (50psia) to 1,034kPa (150 psia). The second solvent stream remains in the second stripper column solvent line 124 and is combined with the second recovered solvent stream in the second solvent recovery line 114, and then condensed by a cooler and received in a solvent reservoir 128, which solvent reservoir 128 may include a reservoir for removing water. Recovered solvent is pumped from reservoir 128 through solvent recycle line 130 as needed to replenish the second separated solvent stream in second separated solvent line 96 to facilitate extraction in second extraction column 84. Make-up second solvent may be added through second make-up line 132. Essentially, a second solvent-free DAO stream is provided in a second deasphalting line 126 comprising from 10 wt% to 30 wt% of the heavy feed in the heavy feed line 20, resulting in an overall DAO recovery of from 40 wt% to 80 wt% of the heavy feed in the heavy feed line.

The second bitumen stream in the second bitumen line 92 contains a greater concentration of aromatic compounds than in the first stripped bitumen stream in the first stripped bitumen line 56' or than in the first bitumen stream in the first bitumen line 32 (except for the solvent in the second bitumen stream). However, the second pitch stream comprises the second solvent that must be removed. The second bitumen stream in second bitumen line 92 is heated in a heater or by heat exchange and fed to second bitumen stripper 110 through a first bitumen inlet 92i above the inlet of inert gas line 128 and in downstream communication with said second bitumen line 92 to produce a second solvent recovery stream in a second solvent recovery line 114 extending from the top of second bitumen stripper column 110 and a second solvent-depleted stripped bitumen stream in a second stripped bitumen line 116 extending from the bottom of second bitumen stripper column 110. An inert gas, such as steam from line 112, distributed below second pitch inlet 92i can be used as the stripping fluid in second pitch stripper column 118. Second bitumen stripper column 110 will typically operate at 204 ℃ (400 ° f) to 299 ℃ (570 ° f) and 344kPa (50psia) to 1,034kPa (150 psia).

Stripping the second asphalt stream in the second asphalt stripper column 110, as performed in the first stage of solvent deasphalting 12, can produce a second stripped asphalt stream that can be reprinted and that appears difficult to consistently remove from the second asphalt stripper. Thus, a portion of the product stream from the fractionation column 140 is mixed with the second stripped pitch stream in the bottom of the second pitch stripper column 110 to facilitate conveying the second pitch stream to the calciner 80. In one aspect, the product stream that cuts the second bitumen stream can be gas oil that is withdrawn from gas oil line 148' and sent in cutter line 132 to second bitumen stripper column 110. The product stream may enter second bitumen stripper column 110 at an inlet located at or below the inlet for stripping inert gas from line 112. The stripped pitch stream cut from the product stream from the cutter line 132 may be conveyed to the calciner 80 in a second stripped pitch line 116. In one aspect, the stripped pitch stream cut from the product stream in the second stripped pitch line 116 can be sent to the fractionation column 140 in the second stripped pitch line 116, where a majority of the product stream will flash off as a result of the fractionation column 140 operating hotter than the second pitch stripper 110. The fractionation column 140 will be operated to allow the second pitch stream to enter the bottoms line 150 and be transported in the bottoms line 150 from the fractionation column 140 to the calciner 80.

With these noted exceptions, the embodiment of fig. 2 operates as the embodiment in fig. 1.

Examples

The stream of stripped solvent deasphalted pitch at 70% lift was subjected to rotary calcination using indirect heating in a self-inerting environment at a pressure of 48kPa (absolute) and within the temperature range shown in the table below. The calcined solid was recovered from the calcination and subjected to crucible heating at 950 ℃ to determine a residue of volatile hydrocarbons that were not recovered according to ASTM D3175. The fraction of volatile hydrocarbons in the calcined solid stream that were not recovered from the stripped pitch feed is indicated in the table.

Run number	Mode of operation	Temperature range of from DEG C	Volatile hydrocarbon, wt.%
				1	DC (once-through)	403-503	12.2
2	Direct current	420-529	11.7
				3	Dry solids recycle	425-506	8.0

Calcination leaves very little volatile hydrocarbons unrecovered. Solids recycle further minimizes the presence of volatile hydrocarbons on the calcined solids.

Detailed description of the preferred embodiments

While the following is described in conjunction with specific embodiments, it is to be understood that this description is intended to illustrate and not limit the scope of the foregoing description and the appended claims.

A first embodiment of the invention is a process for extracting lighter hydrocarbons from heavier hydrocarbons, the process comprising deasphalting a heavy hydrocarbon feedstream with a solvent stream to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feedstream, and providing a pitch stream containing a greater concentration of aromatic compounds than in the feedstream; calcining the pitch stream to produce a vapor product stream and provide a calcined solid stream; and separating the vapor product stream to provide a product stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, further comprising feeding the pitch stream to a separator and then calcining the pitch stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, wherein the process further comprises feeding the vapor product stream to the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the separator is a fractionation column and the bitumen stream absorbs heat from the fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, further comprising stripping the pitch stream to separate a solvent recovery stream from the pitch stream to provide a calcined stripped pitch stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the heavy hydrocarbon feed stream is a first bitumen stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream, and the bitumen stream is a second bitumen stream, and the process further comprises deasphalting the first heavy hydrocarbon stream with the 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 providing the first bitumen stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, further comprising stripping the pitch stream to separate a solvent recovery stream from the pitch stream to provide a stripped pitch stream, calcining the stripped pitch stream, and mixing the product stream with the stripped pitch stream prior to calcining. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the calcining step is performed in an elongated vessel wherein the stream of pitch moves horizontally from an inlet end to an outlet end while being heated. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, wherein the process further comprises fractionating the vapor product stream to provide a plurality of product streams. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, the method further comprising separating a deasphalted oil stream into a separated solvent stream and a separated deasphalted oil stream, and stripping the separated deasphalted oil stream to provide a stripper solvent stream and a deasphalted stream, and recovering the solvent recovery stream, the separated solvent stream and the stripper solvent stream to the deasphalting step.

A second embodiment of the invention is an apparatus for solvent deasphalting comprising an extraction column having a heavy feed inlet and a solvent inlet, a deasphalted oil line extending from the top of the first extraction column and a pitch line extending from the bottom of the extraction column; a calciner in downstream communication with the bitumen line; and a separator in downstream communication with the calciner. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the 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 the top of the calciner. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the separator is in downstream communication with the pitch line and the calciner is in downstream communication with the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph, the plant further comprising a pitch stripper column comprising a pitch inlet above the inert gas inlet and in downstream communication with the pitch line, and a solvent recovery line extending from an overhead of the pitch stripper column and a stripped pitch line extending from a bottom of the pitch stripper column, wherein the calciner is in downstream communication with the pitch stripper line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph, the plant further comprising a second extraction column in communication with the pitch line, the second extraction column having a second heavy feed inlet and a second solvent inlet, a second deasphalted oil line extending from the top of the second extraction column and a second pitch line extending from the bottom of the second extraction column, and the calciner is in downstream communication with the second pitch line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph, wherein the apparatus further comprises: a deasphalted oil separator having a separator solvent line extending from the overhead of the deasphalted oil separator and a separator DAO line extending from the bottom of the deasphalted oil separator; and a deasphalted oil stripper column having a deasphalted oil stripper inlet above the inert gas inlet and in downstream communication with the separator DAO line, and having a stripper solvent line extending from the top of the deasphalted oil stripper column and a DAO product stream extending from the bottom of the deasphalted oil stripper column.

A third embodiment of the invention is a process for extracting lighter hydrocarbons from heavier hydrocarbons, the process comprising deasphalting a heavy hydrocarbon feedstream with a solvent to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feedstream, and providing a pitch stream containing a greater concentration of aromatic compounds than in the feedstream; passing the bitumen stream to a fractionation column; and calcining the bitumen stream from the fractionation column to gasify light hydrocarbons and crack heavier hydrocarbons. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph, wherein the process further comprises fractionating the vapor product stream from the calciner in the fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the heavy hydrocarbon feed stream is a first bitumen stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream, and the bitumen stream is a second bitumen stream, and the process further comprises deasphalting the first heavy hydrocarbon stream with the 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 providing the first bitumen stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the calcining step is conducted in an elongated vessel wherein the stream of pitch moves horizontally from the inlet end to the outlet end while being heated.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent and can readily ascertain the essential characteristics of the present invention without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. Accordingly, the foregoing preferred specific embodiments are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever, and is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

In the foregoing, all temperatures are shown in degrees celsius and all parts and percentages are by weight unless otherwise indicated.

Claims

1. A method for extracting lighter hydrocarbons from heavier hydrocarbons, the method comprising:

deasphalting a heavy hydrocarbon feedstream with a solvent stream to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feedstream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feedstream;

calcining the pitch stream to produce a vapor product stream and provide a calcined solid stream; and

separating the vapor product stream to provide a product stream.

2. The method of claim 1, further comprising feeding the pitch stream to a separator prior to calcining the pitch stream.

3. The process of claim 2, further comprising feeding the vapor product stream to the separator.

4. The process of claim 1, wherein the heavy hydrocarbon feed stream is a first bitumen stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream, and the bitumen stream is a second bitumen stream, and the process further comprises:

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 providing the first asphalt stream containing a greater concentration of aromatic compounds than in the first heavy hydrocarbon stream.

5. An apparatus for solvent deasphalting, the apparatus comprising:

an extraction column having a heavy feed inlet and a solvent inlet, a deasphalted oil line extending from the top of the first extraction column, and a pitch line extending from the bottom of the extraction column;

a calciner in downstream communication with the pitch line; and

a separator in downstream communication with the calciner.

6. The plant of claim 5 wherein the 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 the top of the calciner.

7. The plant of claim 5 further comprising a pitch stripper column comprising a pitch inlet above the inert gas inlet and in downstream communication with the pitch line, and a solvent recovery line extending from the top of the pitch stripper column and a stripped pitch line extending from the bottom of the pitch stripper column, wherein the calciner is in downstream communication with the pitch stripper line.

8. The plant of claim 5 further comprising a second extraction column in communication with the pitch line, the second extraction column having a second heavy feed inlet and a second solvent inlet, a second deasphalted oil line extending from the top of the second extraction column and a second pitch line extending from the bottom of the second extraction column, and the calciner being in downstream communication with the second pitch line.

9. A method for extracting lighter hydrocarbons from heavier hydrocarbons, the method comprising:

deasphalting a heavy hydrocarbon feedstream with a solvent to extract a deasphalted oil stream containing a greater concentration of aliphatic compounds than in the feedstream and provide a pitch stream containing a greater concentration of aromatic compounds than in the feedstream;

passing the bitumen stream to a fractionation column; and

calcining the pitch stream from the fractionation column to gasify light hydrocarbons and crack heavier hydrocarbons.

10. The process of claim 9, wherein the heavy hydrocarbon feed stream is a first bitumen stream, the solvent stream is a second solvent stream, the deasphalted oil stream is a second deasphalted oil stream, and the bitumen stream is a second bitumen stream, and the process further comprises: