CA1246482A - Method to process heavy crude oils - Google Patents
Method to process heavy crude oilsInfo
- Publication number
- CA1246482A CA1246482A CA000468764A CA468764A CA1246482A CA 1246482 A CA1246482 A CA 1246482A CA 000468764 A CA000468764 A CA 000468764A CA 468764 A CA468764 A CA 468764A CA 1246482 A CA1246482 A CA 1246482A
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- Canada
- Prior art keywords
- weight
- residue
- weight percent
- heavy crude
- insolubles
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G53/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes
- C10G53/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only
- C10G53/04—Treatment of hydrocarbon oils, in the absence of hydrogen, by two or more refining processes plural serial stages only including at least one extraction step
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G55/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by at least one refining process and at least one cracking process
- C10G55/02—Treatment of hydrocarbon oils, in the absence of hydrogen, by at least one refining process and at least one cracking process plural serial stages only
- C10G55/06—Treatment of hydrocarbon oils, in the absence of hydrogen, by at least one refining process and at least one cracking process plural serial stages only including at least one catalytic cracking step
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
A METHOD TO PROCESS HEAVY CRUDE OILS
ABSTRACT OF THE INVENTION
The invention relates to a method to process heavy crude oils in atmospheric distillation, vacuum distillation and catalytic cracking units; the method is characterized by a particular stage in which a residue of the primary distillation is fed into a contaminant extraction unit, such residue mainly comprising asphaltenes, sulfur and metals such as Fe, Cu, Ni, and V
by using selective solvents. Once the contaminants are removed, the process is carried out according to the following steps: the extract obtained is fed into a normal vacuum distillation unit; the vacuum gas oil stream is fed into a catalytic cracking unit and the residue is fed from the vacuum unit into processing units such as the viscosity breaking, coking, asphalt and fuel oil preparation units.
ABSTRACT OF THE INVENTION
The invention relates to a method to process heavy crude oils in atmospheric distillation, vacuum distillation and catalytic cracking units; the method is characterized by a particular stage in which a residue of the primary distillation is fed into a contaminant extraction unit, such residue mainly comprising asphaltenes, sulfur and metals such as Fe, Cu, Ni, and V
by using selective solvents. Once the contaminants are removed, the process is carried out according to the following steps: the extract obtained is fed into a normal vacuum distillation unit; the vacuum gas oil stream is fed into a catalytic cracking unit and the residue is fed from the vacuum unit into processing units such as the viscosity breaking, coking, asphalt and fuel oil preparation units.
Description
41~
BACKGROUND OF THE INVENTION
The procedure to handle heavy crude oils with a high content of asphaltenes (over 7 weight ~; not soluble in nC5), is characterized by removing contaminants by means of an extraction stage by selective solvents in order to obtain an extract whose properties are similar to those of an atmospheric light residue (with less contents of asphaltenes) and a stream where crude contaminants known as bottGms are concentrated.
The growing worldwide demand for energy, together with technology breakthroughs, have encouraged the development of more and more complex procedures to integrally recover distillates and residues derived from crude oils.
Over the years, the oil industry needs have undergone many changes; at present, it provides more heavy crude oi~s.
A crude oil is a mixture mainly constituted by several hydrocarbons and in a minor proportion, compounds containing in their molecules elements such as sulfur, nitrogen, oxygen, vanadium, nickel, --iron, and copper, among others. Generally, a crude oil whose specific gravity is high is known as a heavy crude oil, generally signifying that in its composition the low boiling point hydrocarbons are present in a lower proportion than in those oils known as light crudes; however, when defining thus a heavy crude oil, the chemical nature of its compounds is not considered and consequently its quality is not pin-p~i~ted even if in their analysis, data normally determining the crude quality are included.
For the same specific gravity, i.e. API, quality of a crude can vary greatly since the yield of products may be quite different or the availability of some types of products may substantially increase the costs of its process or sometimes they may partially or totally impair the normal refining procedure.
Crude oils present particular behaviors in their various recovery stages, these behaviors depend on the nature and physical and chemical properties of hydrocarbons.
The main stages correspond to production, handling, refining and marketing.
Traditionally, light and middle hydrocarbons have been recovered, and recovery of heavier crudes makes it necessary to develop new technologies for these reserves to be commercia~ly exploitable. Also, light and middle crudes are easily dehydrated and transported through pipes. Heavy crude oils, on the contrary, due to their high viscosity and specific weight are difficult to handle and more costly transportation systems are required.
lS Heavy crude oils, especially those with high contents of asphaltenes, will also require special processin~ plants.
Hence, marketing on a world wide basis of heavy crude oils will also present particular characteristics.
As mentioned, standard techniques are based on the recovery of light and middle consistency hydrocarbons. The refin~ries to process these products are adapted to a typical scheme in order to recoYer fuels generally consistent of the following refining sequence:
atmospheric distillation, vacuum distillation of atmospheric residues, upgrading of gasolines by catalytic cracking of vacuum gas oils and viscosity breaking of vacuum distillation residues.
Applicant has developed a processing scheme for heavy crude oils with a high content of asphaltenes, including the following stages: atmospheric distillation, selective extraction with solvents, vacuum distillation and viscosity breaking. In this process the feed for the extraction unit is bituminous material which is a residue having an initial boiling temperature of 300 to 470C, derived from distilling heavy crude oil.
.
12~
SUMM~RY OF THE I~VE~TION
According to the me~hod of this invention, heavy crude oils containing high levels of asphaltenes and a paraffinic and naphthenic base are processed. The process stages firstly comprise subjecting the crude to a primary distillation under atmospheric pressure, obtaining thus a residue at an initial boiling temperature of 300~-470C.
Immediately thereafter, the process is characterized by the residue being subject to a selective extraction with C4 - C7 aliphatic solvents or a mixture thereof, recovering through the top an extract with properties similar to those of a residue of light crude atmospheric distillation. The extract derived is immediately subject to refining stages such as vacuum distillation; catalytic cracking, and viscosity breaking, coking, preparation of asphalts and fuel oils from vacuum residues. Through the bottom a stream is recovered where the crude contaminants are concentrated.
Therefore, an object of this invention is a method to process heavy crude oils with high contents of asphaltenes allowing the provision of an extract whose asphaltene and metal percentages are similar to those in a light crude residue for further processing in the conversion units, as mentioned.
Another purpose of this invention is to provide a method to process heavy crude oils which allows a comparatively increase in the distillate yields in relation to the conventional heavy crude oil processing.
Another purpose is to provide a heavy crude oil processing method allowing utilization of crude oil and the refining of residues thereof in conventional, easy to operate processing units.
One more purpose of this invention is to provide a new technique to process heavy crude oils to take advantage of the growing reserve of crudes with high contents of asphaltenes and metals.
12~6~32 The present invention resides in a method for processing heavy crude oils, which comprises distilling a 100% heavy crude oil feedstock containing at least 7 weight percent n-pentane insolubles under atmospheric pressure to obtain an atmospheric distillation residue;
contacting said atmospheric distillation residue with a selective solvent comprising a C4 to C7 aliphatic hydrocarbon or mixtures thereof in an extraction column to extract asphaltenes, carbon, sulfur and metals from said atmospheric distillation residue, said extraction column having a top temperature of 50 - 250C, and a bottom temperature of 40 - 230C while being operated under a pressure of 3-40 kg/cm2 with a solvent-hydrocarbon volume ratio of 2:1 to 1OD1; withdrawing an overhead fraction and a residue fraction from said extraction column, said overhead fraction having an API gravity of 10-18, an SSF viscosity at 50C of 100 to 3,500, 1.0-75 weight percent insolubles in n-pentane and 0.20-5.0 weight percent insolubles in n-heptane, a Ramsbottom carbon of 4.0-12.0 weight percent, 2.0 to 5.0 weight percent sulfur and 75 to 250 ppm metals comprising nickel and vanadium;
subjecting said overhead fraction to vacuum distillation in a vacuum distillation column at a temperature of 300C
- 540C to recover a gas oil stream and a residue stream;
catalytically cracking said gas oil stream and feeding said residue stream to a viscosity breaking unit; and viscosity breaking the residue stream.
DETAILED DESCRIPTION OF THE INVENTION
_ The reserve of light crude oils at present has been decreasing in several oil producing countries, while the heavy crude oil reserve has increased. Refining these crudes requires several techniques.
Classification of crudes - At present there are several classes. From the commercial point of view, crude oils have been classified according to their API gravity in: light ( > 30 API); middle (20 to 30 API); heavy (10 r ~6~
to 20 API), and superheavy ( < 10 API). There are also classifications that take into account the characterization factor, the correlation index and the viscosity gravity constant this latter defining the prevailing chemica~ composition; within these classifications, crudes with a paraffinic, mixed and naphthenic base are included.
Classifications available so far, do not indicate the use of distillates for each crude nor the degree of refining to be applied for an economical process.
Consequently, an arbitrary classification given from the process viewpoint may be that a heavy crude oil, is that which generates vacuum residua requiring an antieconomical dilution to become commercial fuel oil.
Heavy crude oils. According to the commercial classification, heavy crude oils are those presenting gravities lower than 20 API. Other characteristics ascribable to heavy crude oils are: their high viscosity, high contents of metals, mainly nickel and vanadium; high contents of sulfur and abundant existence of carbon residues consisting of asphaltenes and Ramsbottom or Conradson carbon. It has been observed practically, that all heavy crude oils generate amounts above 35 vol% of fuel oils with a 500 SSF viscosity derived from vacuum distillation residues.
In addition, it can be stated that a heavy crude oil is that which necessarily requires its process scheme to include a secondary refining process, such as extraction using selective solvents to separate asphaltenes and contaminants or catalytic processes to isolate undesirable compounds such as carbon, sulfur and metals.
Contaminants. The presence of these compounds found in heavy crude oils, strongly affects the various refining stages. Thus, sulfur in the primary distillation process restrains the distillate recovery thoroughness due ;4~
to the corrosion caused by some sulfur compounds at high temperatures. In this case, special and expensive alloys are required in process equipment . The presence of these compounds in distillates makes it necessary to further treat them for their isolation as otherwise they will not meet quality specifications.
In the secondary refining system conventionally applie~d to refineries in order to recover additional gasoline volumes, the influence of these contaminants is noticed. Their presence limits the recovery of feedstock, which is to be recycled, since in most cases catalytic agents are used which are easily poisoned and deactivated by the presence of contaminants, especially metals.
Regarding heav~ industrial fuels normally prepared from asphalt residues, the presence of noxious compounds in heavy crude oils is also noticed to attack normal equipment burning heavy fuels. Accelerated corrosive effects are observed as well.
~s for hydrocarbons with a low hydrogen-carbon ratio, it may be mentioned that an indirect measure of the refining system's complexity and severeness to be applied in processing heavy crude oils is given by the asphaltene contents present in crude oils.
Thus, a heavy crude oil with low asphaltene contents is easier to refine than a crude of equal API
gravity but with a high content of asphaltenes.
A behavior measure of crude in processes involving heating in industrial processes, is made by the value of Ramsbottom carbon which for practical purposes may be interpreted as the trend towards carboni~ation.
This means that in spite of a crude having distillable hydrocarbons, when the Ramsbottom carbon is high, many of the above hydrocarbons are not to be derived from distillation since by increasing the temperature to the required level, carbonization will occur.
3~46~
The values obtained when determining insolubles in pentane and heptane are a measure of the asphaltene contents, asphaltenes being compounds of a very high molecular weight made of carbon, hydrogen, nitrogen, oxygen, and metals. As already stated, asphaltenes in a heavy crude oil cause many problems when refining the latter.
Analysis of heavy crude oils furnishes various values as to the asphaltene contents. This is repeated also for Ramsbottom carbon. On the other hand, even though atmospheric distillates from a typical heavy crude oil are comparable to those in light oils insofar as their characteristics related to their use as fuel, a great difference in the vacuum gas oil chemical composition is observed, however; the gas oil derived from heavy crude oils, have a larger amount of aromatics and consequently a higher carbon-hydrogen ratio.
This ratio shows also a trend to carbonization and furthermore, as heavier fractions are analyzedt such ratio continues to increase. This means that even prior to considering asphaltenes, heavy gas oils from heavy crude oils, because of their high carbon hydrogen ratio, are potential products for carbonization presenting also high viscosity since in their chemical composition there is a high lèvel of polyaromatics.
Certain properties of heavy crude oils and their distillates and residues resulting from their normal processing are described below.
CRUDE OIL
A heavy crude oil with a 21.8 API gravity may be considered as a heavy crude oil, intermediate between paraffinic and naphthenic as shown by the characterization factor observed (Kuop = 11.7~. With high contaminant values such as sulfur (3.2 weight ~), Ramsbottom carbon (10.~ weight %), metals Ni + V (350 ppm) and nC5 insolubles (14.7 weigh+ %). As to the recovery of ~!,' !
"~
lZ~6g~
g atmospheric distillates (46 vol %) low yields may be considered.
GASOLI~S
Gasolines recovered from crudes as stated above have high sulfur values (280 to 2800 ppm).
TURBO FUELS
High values of sulfur (2900 to 3800 ppm) and freezing point (-38 to -48C) are observed~ Flash point is good (50 to 70C ) as is the aromatic compound contents (18 to 21 vol %).
KEROSENÆS
These fractions present acceptable values of sulfur ( 0.38 to 0.65 weight ~) and flash point (60 to 89C). Smoke index is low (14 to 15 mm).
DIESEL
High values of sulfur are observed (0.54 to 1.6 weight %) and normal pour point (-42 to 0C). In terms of cetane index (47.5 to 51.5) and carbon residues (0.017 to 0~060 weight %) these fractions are of good quality.
HEAVY DISTILLATES
Metal contents is low (Ni + V = ppm) as opposed to sulfur (2.2 to 2.9 weight %). Viscosity index (60 to 69) suggest the possibility to recover paraffinic lube oils.
RESIDUES
Residues recovered from vacuum distillation have high levels of sulfur (3.8 to 5.0 weight %), metals (~i +
V = 500 - 800 ppm), insolubles in pentane (20-33 weight %) and viscosi~y at 98.9C (340 - 50,000 cs).
Based on the above, one comes to the conclusion that a heav~ crude oil, due to its chemical characteristics, is a crude oil with a tendency to carbonization in industrial refining operations and because of its high contents of metals, it will produce vacuum gas oil with high concentrations thereof which will affect the proper operation of catalytic cracking plants.
~Z~
Consequentlyl the object of this lnvention is to provide a method to eliminate the products mentioned from heavy crude oils, i.e. those with high values of Ram~bottom carbon, asphaltenes and metals so that the processes to which the crude oil is subject during its refining, may operate with a proper efficiency as will a typical light crude oil.
The main characteristics of a heavy crude oil subject to treatment under this invention are described below:
CRUDE OIL ANALYSIS
Specific ~eight 0.918 API gravity 21.8 Sulfur, weight ~ 3.2 Viscosity at 37.8C, SSU 370 Ramsbottom Carbon, weiyht ~ 10.4 Asphaltenes, weight % 14.7 Vanadium, ppm 270 ~ickel ppm 48 20 Kuop (characterization factor) 11.7 Processing a typical crude oil hereunder is carried out in the following stages:
A 100% crude oil stream is treated by distillation. A stream of gas and distillate fractions with the following characteristics is obtained:
DEGREE OF FRACTIO~ YIELDAPI GRAVITY
VOL.%
Gas (IBT-5C) 1.0 Gasoline (50-210C) 19.5 57.7 30 Kerosene (210-290C) 10.5 38.8 - Diesel (290-400C) 15~5 27.5 Heavy gas oil (400-470C) 7.5 27.1 From atmospheric distillation bottoms a residue with a yield of 53.5 volume ~ and a 400C IBT tInitial Boiling Temperature) is obtained. The residue is composed as follows:
ILZ~4~2 COMPOSITION
Ramsbottom carbon, weight % 19.7 Viscosity, SSF at 50C 70,000 Specific weight, 20/4C 1,026 API gravity 6.0 Metals, Fe, ppm 27 Metals, Cu ppm 2 The extract produced under these conditions has the following characteristics:
EXTRACTEXTRACT
(1) (2) API gravity 12.113.5 Viscosity, SSF at 50C 381 732 nC5 insolubles, weight % 2.2 3.2 nC7 insolubles, weight % 0.9 0.4 Ramsbottom Carbon, weight % 7.5 7.9 Sulfur, weight % 3.53.9 Metals (Ni ~ V), ppm 120 131 Yield, vol. % 65.4-67.3 63.0-69.6 The residues produced at 400C and 470C from the extraction of bottoms after treatmant with solvents, has the following characteristics:
BOTTOMSBOTTOMS
(1) (2) Density (Beckman) 1.0711.13 Ramsbottom carbon, weight ~ 40.0 42.1 nC5 insolubles, weight % 70.2 77.2 nC7 insolubles, weight ~ 60.0 63.6 Qils, weight ~ 16.5 9.3 Resins, weight % 13.9013.6 Metals, (Ni + V), ppm 1574 1899 Sulfur, weight % 6.7 7.0 Carbon/Hydrogen, weight ~ 8~96 10.76 Gross Heat value (BTU/lb) 16,811 16,341 Melting point, C 153 160 Yield, vol. % 34.035.0 `:~
12~6~2 The extract derived from the extraction treatment with solvents is immediately subject to conventional vacuum distillation, catalytic cracking and viscosity breaking stages.
During the vacuum distillation a gas oil fraction with a 540C IBT (Initial Boiling Temperature) and a 40-41 volume ~ (1) and 36-38 volume ~ (2) yield is produced.
Comparative characteristics of a feedstock (vacuum gas oil of catalytic cracking from a light crude, with feedstock into catalytic cracking from a light crude, with feedstock into catalytic cracking from heavy crude oil extracts treated with this method) are described in Table 1.
VACUUM GAS OIL
LIGHT CRUDE EXTRACT EXTRACT
(1) (2) API gravity 25.5 19.6 18.9 Ramsbottom carbon, weight % 0.4 0.3 0.3 nC5 insolubles, weight % 0 0 0 Sulfur, weight % 2.0 2.5 2.7 Viscosity, SSU, 98.9C 36 52 55 Metals (Ni + V), ppm 0.6 1.4 1.5 Metal factor 3.0 4.2 5.4 Residue in the vacuum distillation unit with a 540C FBP (Final Boiling Point) has a 59-60 volume % (1) and 62-64 volume % (2) yield.
According to the results shown on the above table, it may be seen that extracts from vacuum distillation produced by the technique to process heavy crude oils under this invention, virtually exhibit the same major characteristics of a vacuum extract derived from light crude oils. Among these characteristics a trend to carbonization is noticed in both cases with very similar values, i.e.:
~t;4~3~
LIGHT CRUDEEXTRACT EXTRACT
(1) (2) Ramsbottom carbon weight % 0.4 0.3 0.3 Likewise, it may be seen in the table that the asphaltene contents is nil in both cases, that is:
LIGHT CRUDE EXTRACT EXTRACT
(1) (2) nC5 insolubles, weight 0 0 0 In order to better illustrate the invention, in the following examples the various modes to carry out the heavy crude oil processing are described. Of course this does not limit the scope of the invention.
A 100~ feedstock with heavy crude oil is prepared. It has the following characteristics.
Specific weight, 20/4C 0.920 API gravity 22.6 Sulfur, weight ~ 3.1 Viscosity at 37.8~C, SSU 380 20 Ramsbottom carbon, weight % 10.7 Asphaltenes, weight % 14.7 Vanadium, ppm 283 Nickel, ppm 51 Kuop 11.7 This feedstock is immediately subject to atmospheric distillation to obtain a stream with gas and distillate fractions having the following characteristics:
DEGREE OF STRIPPING FRACTIONPRODUCT YIELD
VOL. %
30 Gas (IBT 50C) 1.0 Gasoline (50-210C) 19.5 Kerosene (210-290C) 10.5 Diesel (290-400C) 15.5 Heavy gas oil (400-470C) 7.5 Residuum ~70C + 46.0 ;~
~.
6~32 With selective solvents comprising an isopentane (iC5) and normal pentane (nC5) mixture, the resulting residue is immediately trea~ed, to extract asphaltenes, carbon, sulfur, and metals, under the following conditions:
Top temperature, C 138-142C
Bottom temperature, C 118-122C
Solvent/Hydrocarbon Ratio, vol/vol 4:1-7:1 Pressure, Kg/cm2 22-24 The results obtained and the feedstock and product properties in this extraction stage are listed below:
FEEDSTOCK RESIDUE EXTRACT BOTTOMS
IBT:470C
Yield, vol. % 100.0 64.0 36.0 API gravity 4.92 12.9 __ Specific weight, 20/4C 1.0342 0.977 1.130 Viscosity SSF C 504 x 105 828 --82.2 8,850 100 --98.9 1,980 -- --Total sulfur, weight % 4.7 4.2 6.7 Ramsbotton carbon, weight % 19.9 7.9 39.3 Water and sediment, Vol. % 0.3 0.2 -~
nC5 insolubles, weight % 28.3 1.1 76.3 nC7 insolubles, weight % 20.9 0.4 60.0
BACKGROUND OF THE INVENTION
The procedure to handle heavy crude oils with a high content of asphaltenes (over 7 weight ~; not soluble in nC5), is characterized by removing contaminants by means of an extraction stage by selective solvents in order to obtain an extract whose properties are similar to those of an atmospheric light residue (with less contents of asphaltenes) and a stream where crude contaminants known as bottGms are concentrated.
The growing worldwide demand for energy, together with technology breakthroughs, have encouraged the development of more and more complex procedures to integrally recover distillates and residues derived from crude oils.
Over the years, the oil industry needs have undergone many changes; at present, it provides more heavy crude oi~s.
A crude oil is a mixture mainly constituted by several hydrocarbons and in a minor proportion, compounds containing in their molecules elements such as sulfur, nitrogen, oxygen, vanadium, nickel, --iron, and copper, among others. Generally, a crude oil whose specific gravity is high is known as a heavy crude oil, generally signifying that in its composition the low boiling point hydrocarbons are present in a lower proportion than in those oils known as light crudes; however, when defining thus a heavy crude oil, the chemical nature of its compounds is not considered and consequently its quality is not pin-p~i~ted even if in their analysis, data normally determining the crude quality are included.
For the same specific gravity, i.e. API, quality of a crude can vary greatly since the yield of products may be quite different or the availability of some types of products may substantially increase the costs of its process or sometimes they may partially or totally impair the normal refining procedure.
Crude oils present particular behaviors in their various recovery stages, these behaviors depend on the nature and physical and chemical properties of hydrocarbons.
The main stages correspond to production, handling, refining and marketing.
Traditionally, light and middle hydrocarbons have been recovered, and recovery of heavier crudes makes it necessary to develop new technologies for these reserves to be commercia~ly exploitable. Also, light and middle crudes are easily dehydrated and transported through pipes. Heavy crude oils, on the contrary, due to their high viscosity and specific weight are difficult to handle and more costly transportation systems are required.
lS Heavy crude oils, especially those with high contents of asphaltenes, will also require special processin~ plants.
Hence, marketing on a world wide basis of heavy crude oils will also present particular characteristics.
As mentioned, standard techniques are based on the recovery of light and middle consistency hydrocarbons. The refin~ries to process these products are adapted to a typical scheme in order to recoYer fuels generally consistent of the following refining sequence:
atmospheric distillation, vacuum distillation of atmospheric residues, upgrading of gasolines by catalytic cracking of vacuum gas oils and viscosity breaking of vacuum distillation residues.
Applicant has developed a processing scheme for heavy crude oils with a high content of asphaltenes, including the following stages: atmospheric distillation, selective extraction with solvents, vacuum distillation and viscosity breaking. In this process the feed for the extraction unit is bituminous material which is a residue having an initial boiling temperature of 300 to 470C, derived from distilling heavy crude oil.
.
12~
SUMM~RY OF THE I~VE~TION
According to the me~hod of this invention, heavy crude oils containing high levels of asphaltenes and a paraffinic and naphthenic base are processed. The process stages firstly comprise subjecting the crude to a primary distillation under atmospheric pressure, obtaining thus a residue at an initial boiling temperature of 300~-470C.
Immediately thereafter, the process is characterized by the residue being subject to a selective extraction with C4 - C7 aliphatic solvents or a mixture thereof, recovering through the top an extract with properties similar to those of a residue of light crude atmospheric distillation. The extract derived is immediately subject to refining stages such as vacuum distillation; catalytic cracking, and viscosity breaking, coking, preparation of asphalts and fuel oils from vacuum residues. Through the bottom a stream is recovered where the crude contaminants are concentrated.
Therefore, an object of this invention is a method to process heavy crude oils with high contents of asphaltenes allowing the provision of an extract whose asphaltene and metal percentages are similar to those in a light crude residue for further processing in the conversion units, as mentioned.
Another purpose of this invention is to provide a method to process heavy crude oils which allows a comparatively increase in the distillate yields in relation to the conventional heavy crude oil processing.
Another purpose is to provide a heavy crude oil processing method allowing utilization of crude oil and the refining of residues thereof in conventional, easy to operate processing units.
One more purpose of this invention is to provide a new technique to process heavy crude oils to take advantage of the growing reserve of crudes with high contents of asphaltenes and metals.
12~6~32 The present invention resides in a method for processing heavy crude oils, which comprises distilling a 100% heavy crude oil feedstock containing at least 7 weight percent n-pentane insolubles under atmospheric pressure to obtain an atmospheric distillation residue;
contacting said atmospheric distillation residue with a selective solvent comprising a C4 to C7 aliphatic hydrocarbon or mixtures thereof in an extraction column to extract asphaltenes, carbon, sulfur and metals from said atmospheric distillation residue, said extraction column having a top temperature of 50 - 250C, and a bottom temperature of 40 - 230C while being operated under a pressure of 3-40 kg/cm2 with a solvent-hydrocarbon volume ratio of 2:1 to 1OD1; withdrawing an overhead fraction and a residue fraction from said extraction column, said overhead fraction having an API gravity of 10-18, an SSF viscosity at 50C of 100 to 3,500, 1.0-75 weight percent insolubles in n-pentane and 0.20-5.0 weight percent insolubles in n-heptane, a Ramsbottom carbon of 4.0-12.0 weight percent, 2.0 to 5.0 weight percent sulfur and 75 to 250 ppm metals comprising nickel and vanadium;
subjecting said overhead fraction to vacuum distillation in a vacuum distillation column at a temperature of 300C
- 540C to recover a gas oil stream and a residue stream;
catalytically cracking said gas oil stream and feeding said residue stream to a viscosity breaking unit; and viscosity breaking the residue stream.
DETAILED DESCRIPTION OF THE INVENTION
_ The reserve of light crude oils at present has been decreasing in several oil producing countries, while the heavy crude oil reserve has increased. Refining these crudes requires several techniques.
Classification of crudes - At present there are several classes. From the commercial point of view, crude oils have been classified according to their API gravity in: light ( > 30 API); middle (20 to 30 API); heavy (10 r ~6~
to 20 API), and superheavy ( < 10 API). There are also classifications that take into account the characterization factor, the correlation index and the viscosity gravity constant this latter defining the prevailing chemica~ composition; within these classifications, crudes with a paraffinic, mixed and naphthenic base are included.
Classifications available so far, do not indicate the use of distillates for each crude nor the degree of refining to be applied for an economical process.
Consequently, an arbitrary classification given from the process viewpoint may be that a heavy crude oil, is that which generates vacuum residua requiring an antieconomical dilution to become commercial fuel oil.
Heavy crude oils. According to the commercial classification, heavy crude oils are those presenting gravities lower than 20 API. Other characteristics ascribable to heavy crude oils are: their high viscosity, high contents of metals, mainly nickel and vanadium; high contents of sulfur and abundant existence of carbon residues consisting of asphaltenes and Ramsbottom or Conradson carbon. It has been observed practically, that all heavy crude oils generate amounts above 35 vol% of fuel oils with a 500 SSF viscosity derived from vacuum distillation residues.
In addition, it can be stated that a heavy crude oil is that which necessarily requires its process scheme to include a secondary refining process, such as extraction using selective solvents to separate asphaltenes and contaminants or catalytic processes to isolate undesirable compounds such as carbon, sulfur and metals.
Contaminants. The presence of these compounds found in heavy crude oils, strongly affects the various refining stages. Thus, sulfur in the primary distillation process restrains the distillate recovery thoroughness due ;4~
to the corrosion caused by some sulfur compounds at high temperatures. In this case, special and expensive alloys are required in process equipment . The presence of these compounds in distillates makes it necessary to further treat them for their isolation as otherwise they will not meet quality specifications.
In the secondary refining system conventionally applie~d to refineries in order to recover additional gasoline volumes, the influence of these contaminants is noticed. Their presence limits the recovery of feedstock, which is to be recycled, since in most cases catalytic agents are used which are easily poisoned and deactivated by the presence of contaminants, especially metals.
Regarding heav~ industrial fuels normally prepared from asphalt residues, the presence of noxious compounds in heavy crude oils is also noticed to attack normal equipment burning heavy fuels. Accelerated corrosive effects are observed as well.
~s for hydrocarbons with a low hydrogen-carbon ratio, it may be mentioned that an indirect measure of the refining system's complexity and severeness to be applied in processing heavy crude oils is given by the asphaltene contents present in crude oils.
Thus, a heavy crude oil with low asphaltene contents is easier to refine than a crude of equal API
gravity but with a high content of asphaltenes.
A behavior measure of crude in processes involving heating in industrial processes, is made by the value of Ramsbottom carbon which for practical purposes may be interpreted as the trend towards carboni~ation.
This means that in spite of a crude having distillable hydrocarbons, when the Ramsbottom carbon is high, many of the above hydrocarbons are not to be derived from distillation since by increasing the temperature to the required level, carbonization will occur.
3~46~
The values obtained when determining insolubles in pentane and heptane are a measure of the asphaltene contents, asphaltenes being compounds of a very high molecular weight made of carbon, hydrogen, nitrogen, oxygen, and metals. As already stated, asphaltenes in a heavy crude oil cause many problems when refining the latter.
Analysis of heavy crude oils furnishes various values as to the asphaltene contents. This is repeated also for Ramsbottom carbon. On the other hand, even though atmospheric distillates from a typical heavy crude oil are comparable to those in light oils insofar as their characteristics related to their use as fuel, a great difference in the vacuum gas oil chemical composition is observed, however; the gas oil derived from heavy crude oils, have a larger amount of aromatics and consequently a higher carbon-hydrogen ratio.
This ratio shows also a trend to carbonization and furthermore, as heavier fractions are analyzedt such ratio continues to increase. This means that even prior to considering asphaltenes, heavy gas oils from heavy crude oils, because of their high carbon hydrogen ratio, are potential products for carbonization presenting also high viscosity since in their chemical composition there is a high lèvel of polyaromatics.
Certain properties of heavy crude oils and their distillates and residues resulting from their normal processing are described below.
CRUDE OIL
A heavy crude oil with a 21.8 API gravity may be considered as a heavy crude oil, intermediate between paraffinic and naphthenic as shown by the characterization factor observed (Kuop = 11.7~. With high contaminant values such as sulfur (3.2 weight ~), Ramsbottom carbon (10.~ weight %), metals Ni + V (350 ppm) and nC5 insolubles (14.7 weigh+ %). As to the recovery of ~!,' !
"~
lZ~6g~
g atmospheric distillates (46 vol %) low yields may be considered.
GASOLI~S
Gasolines recovered from crudes as stated above have high sulfur values (280 to 2800 ppm).
TURBO FUELS
High values of sulfur (2900 to 3800 ppm) and freezing point (-38 to -48C) are observed~ Flash point is good (50 to 70C ) as is the aromatic compound contents (18 to 21 vol %).
KEROSENÆS
These fractions present acceptable values of sulfur ( 0.38 to 0.65 weight ~) and flash point (60 to 89C). Smoke index is low (14 to 15 mm).
DIESEL
High values of sulfur are observed (0.54 to 1.6 weight %) and normal pour point (-42 to 0C). In terms of cetane index (47.5 to 51.5) and carbon residues (0.017 to 0~060 weight %) these fractions are of good quality.
HEAVY DISTILLATES
Metal contents is low (Ni + V = ppm) as opposed to sulfur (2.2 to 2.9 weight %). Viscosity index (60 to 69) suggest the possibility to recover paraffinic lube oils.
RESIDUES
Residues recovered from vacuum distillation have high levels of sulfur (3.8 to 5.0 weight %), metals (~i +
V = 500 - 800 ppm), insolubles in pentane (20-33 weight %) and viscosi~y at 98.9C (340 - 50,000 cs).
Based on the above, one comes to the conclusion that a heav~ crude oil, due to its chemical characteristics, is a crude oil with a tendency to carbonization in industrial refining operations and because of its high contents of metals, it will produce vacuum gas oil with high concentrations thereof which will affect the proper operation of catalytic cracking plants.
~Z~
Consequentlyl the object of this lnvention is to provide a method to eliminate the products mentioned from heavy crude oils, i.e. those with high values of Ram~bottom carbon, asphaltenes and metals so that the processes to which the crude oil is subject during its refining, may operate with a proper efficiency as will a typical light crude oil.
The main characteristics of a heavy crude oil subject to treatment under this invention are described below:
CRUDE OIL ANALYSIS
Specific ~eight 0.918 API gravity 21.8 Sulfur, weight ~ 3.2 Viscosity at 37.8C, SSU 370 Ramsbottom Carbon, weiyht ~ 10.4 Asphaltenes, weight % 14.7 Vanadium, ppm 270 ~ickel ppm 48 20 Kuop (characterization factor) 11.7 Processing a typical crude oil hereunder is carried out in the following stages:
A 100% crude oil stream is treated by distillation. A stream of gas and distillate fractions with the following characteristics is obtained:
DEGREE OF FRACTIO~ YIELDAPI GRAVITY
VOL.%
Gas (IBT-5C) 1.0 Gasoline (50-210C) 19.5 57.7 30 Kerosene (210-290C) 10.5 38.8 - Diesel (290-400C) 15~5 27.5 Heavy gas oil (400-470C) 7.5 27.1 From atmospheric distillation bottoms a residue with a yield of 53.5 volume ~ and a 400C IBT tInitial Boiling Temperature) is obtained. The residue is composed as follows:
ILZ~4~2 COMPOSITION
Ramsbottom carbon, weight % 19.7 Viscosity, SSF at 50C 70,000 Specific weight, 20/4C 1,026 API gravity 6.0 Metals, Fe, ppm 27 Metals, Cu ppm 2 The extract produced under these conditions has the following characteristics:
EXTRACTEXTRACT
(1) (2) API gravity 12.113.5 Viscosity, SSF at 50C 381 732 nC5 insolubles, weight % 2.2 3.2 nC7 insolubles, weight % 0.9 0.4 Ramsbottom Carbon, weight % 7.5 7.9 Sulfur, weight % 3.53.9 Metals (Ni ~ V), ppm 120 131 Yield, vol. % 65.4-67.3 63.0-69.6 The residues produced at 400C and 470C from the extraction of bottoms after treatmant with solvents, has the following characteristics:
BOTTOMSBOTTOMS
(1) (2) Density (Beckman) 1.0711.13 Ramsbottom carbon, weight ~ 40.0 42.1 nC5 insolubles, weight % 70.2 77.2 nC7 insolubles, weight ~ 60.0 63.6 Qils, weight ~ 16.5 9.3 Resins, weight % 13.9013.6 Metals, (Ni + V), ppm 1574 1899 Sulfur, weight % 6.7 7.0 Carbon/Hydrogen, weight ~ 8~96 10.76 Gross Heat value (BTU/lb) 16,811 16,341 Melting point, C 153 160 Yield, vol. % 34.035.0 `:~
12~6~2 The extract derived from the extraction treatment with solvents is immediately subject to conventional vacuum distillation, catalytic cracking and viscosity breaking stages.
During the vacuum distillation a gas oil fraction with a 540C IBT (Initial Boiling Temperature) and a 40-41 volume ~ (1) and 36-38 volume ~ (2) yield is produced.
Comparative characteristics of a feedstock (vacuum gas oil of catalytic cracking from a light crude, with feedstock into catalytic cracking from a light crude, with feedstock into catalytic cracking from heavy crude oil extracts treated with this method) are described in Table 1.
VACUUM GAS OIL
LIGHT CRUDE EXTRACT EXTRACT
(1) (2) API gravity 25.5 19.6 18.9 Ramsbottom carbon, weight % 0.4 0.3 0.3 nC5 insolubles, weight % 0 0 0 Sulfur, weight % 2.0 2.5 2.7 Viscosity, SSU, 98.9C 36 52 55 Metals (Ni + V), ppm 0.6 1.4 1.5 Metal factor 3.0 4.2 5.4 Residue in the vacuum distillation unit with a 540C FBP (Final Boiling Point) has a 59-60 volume % (1) and 62-64 volume % (2) yield.
According to the results shown on the above table, it may be seen that extracts from vacuum distillation produced by the technique to process heavy crude oils under this invention, virtually exhibit the same major characteristics of a vacuum extract derived from light crude oils. Among these characteristics a trend to carbonization is noticed in both cases with very similar values, i.e.:
~t;4~3~
LIGHT CRUDEEXTRACT EXTRACT
(1) (2) Ramsbottom carbon weight % 0.4 0.3 0.3 Likewise, it may be seen in the table that the asphaltene contents is nil in both cases, that is:
LIGHT CRUDE EXTRACT EXTRACT
(1) (2) nC5 insolubles, weight 0 0 0 In order to better illustrate the invention, in the following examples the various modes to carry out the heavy crude oil processing are described. Of course this does not limit the scope of the invention.
A 100~ feedstock with heavy crude oil is prepared. It has the following characteristics.
Specific weight, 20/4C 0.920 API gravity 22.6 Sulfur, weight ~ 3.1 Viscosity at 37.8~C, SSU 380 20 Ramsbottom carbon, weight % 10.7 Asphaltenes, weight % 14.7 Vanadium, ppm 283 Nickel, ppm 51 Kuop 11.7 This feedstock is immediately subject to atmospheric distillation to obtain a stream with gas and distillate fractions having the following characteristics:
DEGREE OF STRIPPING FRACTIONPRODUCT YIELD
VOL. %
30 Gas (IBT 50C) 1.0 Gasoline (50-210C) 19.5 Kerosene (210-290C) 10.5 Diesel (290-400C) 15.5 Heavy gas oil (400-470C) 7.5 Residuum ~70C + 46.0 ;~
~.
6~32 With selective solvents comprising an isopentane (iC5) and normal pentane (nC5) mixture, the resulting residue is immediately trea~ed, to extract asphaltenes, carbon, sulfur, and metals, under the following conditions:
Top temperature, C 138-142C
Bottom temperature, C 118-122C
Solvent/Hydrocarbon Ratio, vol/vol 4:1-7:1 Pressure, Kg/cm2 22-24 The results obtained and the feedstock and product properties in this extraction stage are listed below:
FEEDSTOCK RESIDUE EXTRACT BOTTOMS
IBT:470C
Yield, vol. % 100.0 64.0 36.0 API gravity 4.92 12.9 __ Specific weight, 20/4C 1.0342 0.977 1.130 Viscosity SSF C 504 x 105 828 --82.2 8,850 100 --98.9 1,980 -- --Total sulfur, weight % 4.7 4.2 6.7 Ramsbotton carbon, weight % 19.9 7.9 39.3 Water and sediment, Vol. % 0.3 0.2 -~
nC5 insolubles, weight % 28.3 1.1 76.3 nC7 insolubles, weight % 20.9 0.4 60.0
2~ Oils, weight % 42.0 64.9 10.3 Resins, weight % 29.7 34.0 13.4 Metals, ppm Fe 45 16.2 --Cu 1.0 0.3 --Ni 108 14.2 275 Ductility, cm 150 Softening point, C 50 -- 150 Penetration 100/5/25, 0.1 mm 0 Pour point, C -- +12 --Carbon, weight % 82.2 83.1 82.2 Hydrogen, weight % 9.3 10.2 9.5 ~r ~Z46~
~itrogen, weight % 1.0 0.5 0.5 Basic nitrogen, ppm 1600 987 2473 Benzene insolubles, weight % 0.0 0.0 0.0 Polars, weight ~ 29.7 34O0 13.4 Saturates, weight ~ 13.6 19.6 2.8 Aromatics, weight ~ 28.3 45.2 7.5 Fixed carbon, weight %10.5 0.30 28.9 Ash, weight % 0.10 0.04 0.20 Gross heat value, BTU/lb 17,41618,584 16,175 Cal/g 9,68210,331 8,992 Thereafter, the extract obtained continues its refining processing in vacuum distillation, catalytic cracking, and viscosity breaking units, and the coking, asphalt preparation and fuel oil units.
Vacuum Distillatio~. In this stage a gas oil is pro~uced (FBT-540C) with a 37.8 v~l. yield and a 62.9 vol. % residue (IBT-540C).
Following below are the major characteristics of gas oils and residues derived from this stage.
TYPE OF FEEDSTOCKGAS OIL RESIDUE
CHARACTERISTICS
API gravity 18.58 7.2 Specific weight 20/4C0.938 1.0173 Viscosity, 37.8Cgoo,ooo Viscosity, 98.9C 55 7,950 Total sulfur, weight % 2.7 4.5 Ramsbottom carbon, weight ~ 0.3 15.3 nCs insolubles, weight % 0.0 8.6 Metals, ppm Fe 0.8 1.7 Cu 0.05 9.8 ~i 10~3 36 V 1.2 199 lZ9~4~;~
Flash point, C 204 ~~
Aniline point, C 72 --Benzene insolubles, weight % -- 0-07 Ash, weight ~ 0.06 0.07 Following the same technique as in example 1, the resultant atmospheric residue is treated with a different aliphatic hydrocarbon, such as normal pentane to extract asphaltenes, carbon, sulfur and metals and the following results are obtained:
c5 TYPE OF SOLVENTFEEDSTOCKEXTRACT BOTTOMS
Yield t vol. ~ 100~0 71.3 28.7 API gravity 4.92 11.8 --Specific weight, 20/4C 1.0342 0.985 1.150 Viscosity, SSF C 504 x 105 -- --82.2 8,850 --- --98.g 1,980 -- --Total sulfur, Weight % 4.7 4.4 6.8 Ramsbottom carbon, weight ~ 19.9 10.6 40.6 Water and sediments, vol. % 0.3 0.1 --nCs insolubles, weight ~ 28.3 7.7 79.4 nC7 insolubles, weight % 20.9 4.3 62.1 Oils, weight ~ 42.0 59.1 9.4 Resins, weight ~29.7 33.2 11.2 Metals, ppm Fe 45 7.5 --~t;4~;~Z
Cu 1.0 0.5 --Ni 108 25 300 ~ 642 130 1900 Ductility, cm 150 -- --Softening point 50 -- MI
Penetration 100/5/25, 0.1 mm 380 10 Pour point, C -- +12 __ Carbon, weight % 82.2 81.0 81.9 Hydrogen, weight % 9.3 10.3 10.3 Nitrogen, weight % 1.0 0.5 0.5 Basic nitrogen, ppm1600 1077 2550 Benzene insolubles, weight % o.o o.o o.o Polars, weight % 29.7 33.2 11.2 Saturates, weight %13.6 17.5 3.6 Aromatics, weight ~28.3 41.6 5.8 Fixed carbon, weight %10.5 0.7 34.4 Ash, weight % 0.10 0.03 0.30 Gross heat value, BTU/lb 17,416 18,450 17,244 CAL/g 9,682 10,257 9,586 The extract derived continues being processed into the following stages of vacuum distillation, catalytic cracking, viscosity breaking, coking, asphalt preparation, and fuel oils..
Following the same techniques as in example 1, the atmospheric residue is treated with an aliphatic solvent such as normal hexane, nC5 with the following results:
~2~69182 TYPE OF SOLVENTFEEDSTOCK EXTRACT BOTTOMS
Yield, vol.% 100.0 74.9 25.1 API gravity 4.92 11.2 --Specific weight, 20/4C 1,0342 0.989 l.l70 Viscosity, SSF, C 504 x 105 2370 --82.28,850 234 --98.91,980 --Total sulfur, weight ~4.7 4.45 6.9 Ramsbottom carbon, weight % 19.9 11.4 42.4 Water and sediments, ~ol. % 0.3 0.1 --nCs insolubles, weight % 28.3 10.3 82.0 nC7 insolubles, 20 weight % 20.9 6.0 65.4 Oils, weight ~ 42.0 56.4 8.9 Resins, weight % 29.7 33.3 9.1 Metals, ppm Fe 45 6.0 --Cu 1.0 1.3 __ Ni 108 31 330 Ductility, cm 150 -- --30 Softening point, C 50 -~ --Penetration l00/5/25, 0.1 mm 380 -- --Pour point, C -- +15 --35 Carbon, weight % 82.2 82.8 81.8 `i~
- 19 ~Z46~8~
Hydrogen, weight %9.3 10,2 9 0 ~itrogen, weight %loO 0~5 0~5 Basic nitrogen, ppm1600 1255 2689 Benzene insolubles, weight ~ 0.0 0.0 0.0 Polars, weight % 29~7 33~3 9~1 Saturates, weight %13~6 15~2 3~3 Aromatics, weight ~28~3 41~4 5~6 Fixed carbon, weight % 10~5 2~1 36~8 Ash, weight % 0.10 0. 04 0~37 Gross heat value, BTU/lb 17~416 18~154 16~905 CAL/g 9, 682 10,092 9~398 Extract continues its processing into the following stages: vacuum distillation, catalytic cracking, and viscosity breaking.
The same technique as in example 2~ The atmospheric residuum is treated with an aliphatic solvent, such as a normal heptane nC7 with the following results:
TYPE OF SOLVENTFEEDSTOCK EXTRACT BOTTOMS
Yield, vol. % 100.0 78~6 21~4 API gravity 4~92 10.5 ~~
Specific weight, 20/4C 1~0342 0~994 1~182 Viscosity, SSF C 504 x 105 3270 82~28~850 285 ~~
98~91,980 118 ~~
Total sulfur, weight % 4~7 4~5 7~0 Ramsbottom carbon weight ~ 19.9 11. 8 44~3 64~2 Water and sediments, vol.~ 0.3 0.1 ~~
nCs insolubles, weight % 28.3 12.1 87.8 nC7 insolubles, weight % 20 9 6.7 72.4 Oils, weight % 42.0 55.7 6.7 Resins, weight % 29.7 32.2 5.5 Metals, ppm Fe 45 11.0 --Cu 1.0 0.5 --Ni 108 37 360 Ductility, cm 150 Softening point, C 50 -- --Penetration 100/5/25, 0.1 mm 380 -- --Pour point, C -- ~21 --Carbon, weight % 82.2 83.3 83.7 20 Hydrogen, weight % 9.3 10.8 9.3 Nitrogen, weight ~ 1.0 0.5 0.5 Basic nitrogen, ppm1600 1343 2700 Benzene insolubles, 25 weight % 0 0 0 0 0 0 Polars, weight % 29.7 -- --Saturates, weight %13.6 -- 2.7 Aromatics, weight %28.3 -- 4.1 30 Fixed carbon, weight %10.5 -- --Ash, weight % 0.10 0.03 0.4 Gross heat value BTU/lb 17,416 18,148 16,984 CAL/g 9,682 10,089 9,442 ~ ~.
~6~3Z
Extract produced continues its processing into the following stages; vacuum distillation, catalytic cracking and viscosity breaking.
" , . ,~
.
~itrogen, weight % 1.0 0.5 0.5 Basic nitrogen, ppm 1600 987 2473 Benzene insolubles, weight % 0.0 0.0 0.0 Polars, weight ~ 29.7 34O0 13.4 Saturates, weight ~ 13.6 19.6 2.8 Aromatics, weight ~ 28.3 45.2 7.5 Fixed carbon, weight %10.5 0.30 28.9 Ash, weight % 0.10 0.04 0.20 Gross heat value, BTU/lb 17,41618,584 16,175 Cal/g 9,68210,331 8,992 Thereafter, the extract obtained continues its refining processing in vacuum distillation, catalytic cracking, and viscosity breaking units, and the coking, asphalt preparation and fuel oil units.
Vacuum Distillatio~. In this stage a gas oil is pro~uced (FBT-540C) with a 37.8 v~l. yield and a 62.9 vol. % residue (IBT-540C).
Following below are the major characteristics of gas oils and residues derived from this stage.
TYPE OF FEEDSTOCKGAS OIL RESIDUE
CHARACTERISTICS
API gravity 18.58 7.2 Specific weight 20/4C0.938 1.0173 Viscosity, 37.8Cgoo,ooo Viscosity, 98.9C 55 7,950 Total sulfur, weight % 2.7 4.5 Ramsbottom carbon, weight ~ 0.3 15.3 nCs insolubles, weight % 0.0 8.6 Metals, ppm Fe 0.8 1.7 Cu 0.05 9.8 ~i 10~3 36 V 1.2 199 lZ9~4~;~
Flash point, C 204 ~~
Aniline point, C 72 --Benzene insolubles, weight % -- 0-07 Ash, weight ~ 0.06 0.07 Following the same technique as in example 1, the resultant atmospheric residue is treated with a different aliphatic hydrocarbon, such as normal pentane to extract asphaltenes, carbon, sulfur and metals and the following results are obtained:
c5 TYPE OF SOLVENTFEEDSTOCKEXTRACT BOTTOMS
Yield t vol. ~ 100~0 71.3 28.7 API gravity 4.92 11.8 --Specific weight, 20/4C 1.0342 0.985 1.150 Viscosity, SSF C 504 x 105 -- --82.2 8,850 --- --98.g 1,980 -- --Total sulfur, Weight % 4.7 4.4 6.8 Ramsbottom carbon, weight ~ 19.9 10.6 40.6 Water and sediments, vol. % 0.3 0.1 --nCs insolubles, weight ~ 28.3 7.7 79.4 nC7 insolubles, weight % 20.9 4.3 62.1 Oils, weight ~ 42.0 59.1 9.4 Resins, weight ~29.7 33.2 11.2 Metals, ppm Fe 45 7.5 --~t;4~;~Z
Cu 1.0 0.5 --Ni 108 25 300 ~ 642 130 1900 Ductility, cm 150 -- --Softening point 50 -- MI
Penetration 100/5/25, 0.1 mm 380 10 Pour point, C -- +12 __ Carbon, weight % 82.2 81.0 81.9 Hydrogen, weight % 9.3 10.3 10.3 Nitrogen, weight % 1.0 0.5 0.5 Basic nitrogen, ppm1600 1077 2550 Benzene insolubles, weight % o.o o.o o.o Polars, weight % 29.7 33.2 11.2 Saturates, weight %13.6 17.5 3.6 Aromatics, weight ~28.3 41.6 5.8 Fixed carbon, weight %10.5 0.7 34.4 Ash, weight % 0.10 0.03 0.30 Gross heat value, BTU/lb 17,416 18,450 17,244 CAL/g 9,682 10,257 9,586 The extract derived continues being processed into the following stages of vacuum distillation, catalytic cracking, viscosity breaking, coking, asphalt preparation, and fuel oils..
Following the same techniques as in example 1, the atmospheric residue is treated with an aliphatic solvent such as normal hexane, nC5 with the following results:
~2~69182 TYPE OF SOLVENTFEEDSTOCK EXTRACT BOTTOMS
Yield, vol.% 100.0 74.9 25.1 API gravity 4.92 11.2 --Specific weight, 20/4C 1,0342 0.989 l.l70 Viscosity, SSF, C 504 x 105 2370 --82.28,850 234 --98.91,980 --Total sulfur, weight ~4.7 4.45 6.9 Ramsbottom carbon, weight % 19.9 11.4 42.4 Water and sediments, ~ol. % 0.3 0.1 --nCs insolubles, weight % 28.3 10.3 82.0 nC7 insolubles, 20 weight % 20.9 6.0 65.4 Oils, weight ~ 42.0 56.4 8.9 Resins, weight % 29.7 33.3 9.1 Metals, ppm Fe 45 6.0 --Cu 1.0 1.3 __ Ni 108 31 330 Ductility, cm 150 -- --30 Softening point, C 50 -~ --Penetration l00/5/25, 0.1 mm 380 -- --Pour point, C -- +15 --35 Carbon, weight % 82.2 82.8 81.8 `i~
- 19 ~Z46~8~
Hydrogen, weight %9.3 10,2 9 0 ~itrogen, weight %loO 0~5 0~5 Basic nitrogen, ppm1600 1255 2689 Benzene insolubles, weight ~ 0.0 0.0 0.0 Polars, weight % 29~7 33~3 9~1 Saturates, weight %13~6 15~2 3~3 Aromatics, weight ~28~3 41~4 5~6 Fixed carbon, weight % 10~5 2~1 36~8 Ash, weight % 0.10 0. 04 0~37 Gross heat value, BTU/lb 17~416 18~154 16~905 CAL/g 9, 682 10,092 9~398 Extract continues its processing into the following stages: vacuum distillation, catalytic cracking, and viscosity breaking.
The same technique as in example 2~ The atmospheric residuum is treated with an aliphatic solvent, such as a normal heptane nC7 with the following results:
TYPE OF SOLVENTFEEDSTOCK EXTRACT BOTTOMS
Yield, vol. % 100.0 78~6 21~4 API gravity 4~92 10.5 ~~
Specific weight, 20/4C 1~0342 0~994 1~182 Viscosity, SSF C 504 x 105 3270 82~28~850 285 ~~
98~91,980 118 ~~
Total sulfur, weight % 4~7 4~5 7~0 Ramsbottom carbon weight ~ 19.9 11. 8 44~3 64~2 Water and sediments, vol.~ 0.3 0.1 ~~
nCs insolubles, weight % 28.3 12.1 87.8 nC7 insolubles, weight % 20 9 6.7 72.4 Oils, weight % 42.0 55.7 6.7 Resins, weight % 29.7 32.2 5.5 Metals, ppm Fe 45 11.0 --Cu 1.0 0.5 --Ni 108 37 360 Ductility, cm 150 Softening point, C 50 -- --Penetration 100/5/25, 0.1 mm 380 -- --Pour point, C -- ~21 --Carbon, weight % 82.2 83.3 83.7 20 Hydrogen, weight % 9.3 10.8 9.3 Nitrogen, weight ~ 1.0 0.5 0.5 Basic nitrogen, ppm1600 1343 2700 Benzene insolubles, 25 weight % 0 0 0 0 0 0 Polars, weight % 29.7 -- --Saturates, weight %13.6 -- 2.7 Aromatics, weight %28.3 -- 4.1 30 Fixed carbon, weight %10.5 -- --Ash, weight % 0.10 0.03 0.4 Gross heat value BTU/lb 17,416 18,148 16,984 CAL/g 9,682 10,089 9,442 ~ ~.
~6~3Z
Extract produced continues its processing into the following stages; vacuum distillation, catalytic cracking and viscosity breaking.
" , . ,~
.
Claims (5)
1. A method for processing heavy crude oils, which comprises distilling a 100% heavy crude oil feedstock containing at least 7 weight percent n-pentane insolubles under atmospheric pressure to obtain an atmospheric distillation residue; contacting said atmospheric distillation residue with a selective solvent comprising a C4 to C7 aliphatic hydrocarbon or mixtures thereof in an extraction column to extract asphaltenes, carbon, sulfur and metals from said atmospheric distillation residue, said extraction column having a top temperature of 50° - 250°C, and a bottom temperature of 40°C - 230°C. while being operated under a pressure of 3-40 kg/cm2 with a solvent-hydrocarbon volume ratio of 2:1 to 10:1; withdrawing an overhead fraction and a residue fraction from said extraction column, said overhead fraction having an API gravity of 10-18, an SSF viscosity at 50°C. of 100 to 3,500, 1.0 - 75 weight percent insolubles in n-pentane and 0.20 - 5.0 weight percent insolubles in n-heptane, a Ramsbottom carbon of 4.0 - 12.0 weight percent, 2.0 to 5.0 weight percent sulfur and 75 to 250 ppm metals comprising nickel and vanadium; subjecting said overhead fraction to vacuum distillation in a vacuum distillation column at a temperature of 300°C. to 540°C. to recover a gas oil stream and a residue stream; catalytically cracking said gas oil stream and feeding said residue stream to a viscosity breaking unit; and viscosity breaking the residue stream.
2, The method of claim 1, wherein said atmospheric distillation residue is a bituminous material having an initial boiling temperature of from 300° to 400°C.
3. The method of claim 1, wherein said aliphatic solvent is normal pentane, normal hexane, or normal heptane.
4. The method of claim 1, wherein said residue fraction from said extraction column contains 750 - 3000 ppm metals comprising nickel and vanadium.
5. The method of claim 4, wherein said residue fraction from said extraction column has a density of 0.9 -1.4, a Ramsbottom carbon of 30 - 50 weight percent, 60 - 90 weight percent n-pentane insolubles, 50 - 80 weight percent n-pentane insolubles, 5-8 weight percent sulfur and a melting point of 120° - 200°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MX199652A MX164713B (en) | 1983-12-07 | 1983-12-07 | A METHOD FOR PROCESSING HEAVY RAW |
| MX199652 | 1983-12-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1246482A true CA1246482A (en) | 1988-12-13 |
Family
ID=19748543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000468764A Expired CA1246482A (en) | 1983-12-07 | 1984-11-28 | Method to process heavy crude oils |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS60186590A (en) |
| AR (1) | AR242820A1 (en) |
| BR (1) | BR8406367A (en) |
| CA (1) | CA1246482A (en) |
| DE (1) | DE3444721A1 (en) |
| ES (1) | ES8602913A1 (en) |
| FR (1) | FR2556361B1 (en) |
| IT (1) | IT1180497B (en) |
| MX (1) | MX164713B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002066583A1 (en) * | 2001-02-20 | 2002-08-29 | Jgc Corporation | Method of refining heavy oil and refining apparatus |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1118914B (en) * | 1954-06-03 | 1961-12-07 | Kellogg M W Co | Process for making a catalytic cracking feed |
| US3380912A (en) * | 1967-03-01 | 1968-04-30 | Chevron Res | Combination extraction-demetalation process for heavy oils |
| US3775292A (en) * | 1972-08-01 | 1973-11-27 | Universal Oil Prod Co | Combination process for the conversion of hydrocarbonaceous black oil |
| NL190816C (en) * | 1978-07-07 | 1994-09-01 | Shell Int Research | Process for the preparation of gas oil. |
-
1983
- 1983-12-07 MX MX199652A patent/MX164713B/en unknown
-
1984
- 1984-11-28 CA CA000468764A patent/CA1246482A/en not_active Expired
- 1984-12-03 AR AR84298813A patent/AR242820A1/en active
- 1984-12-04 FR FR8418438A patent/FR2556361B1/en not_active Expired
- 1984-12-05 ES ES538286A patent/ES8602913A1/en not_active Expired
- 1984-12-06 JP JP59258423A patent/JPS60186590A/en active Pending
- 1984-12-07 IT IT12651/84A patent/IT1180497B/en active
- 1984-12-07 DE DE19843444721 patent/DE3444721A1/en not_active Ceased
- 1984-12-10 BR BR8406367A patent/BR8406367A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002066583A1 (en) * | 2001-02-20 | 2002-08-29 | Jgc Corporation | Method of refining heavy oil and refining apparatus |
| US7857964B2 (en) | 2001-02-20 | 2010-12-28 | Jgc Corporation | Method of refining heavy oil and refining apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| ES538286A0 (en) | 1985-12-01 |
| AR242820A1 (en) | 1993-05-31 |
| IT1180497B (en) | 1987-09-23 |
| ES8602913A1 (en) | 1985-12-01 |
| FR2556361A1 (en) | 1985-06-14 |
| DE3444721A1 (en) | 1985-06-20 |
| IT8412651A0 (en) | 1984-12-07 |
| JPS60186590A (en) | 1985-09-24 |
| BR8406367A (en) | 1985-10-08 |
| FR2556361B1 (en) | 1989-06-02 |
| MX164713B (en) | 1992-09-18 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |