FR2543567A1 - Process for the treatment of petroleum residues - Google Patents

Abstract

The invention relates to the field of the oil industry. It relates to a process for the treatment of petroleum residues with a relative density lower than 0.9218, containing a high percentage of asphaltic matter, characterised in that it consists in subjecting, under well-determined conditions, the petroleum residues to a viscosity reduction operation, in then subjecting the residue with a reduced viscosity to a deasphalting operation with saturated aliphatic hydrocarbons, and in then subjecting the deasphalted oil to a hydrotreatment with particular catalysts. Application to the treatment of petroleum residues originating especially from atmospheric-pressure or vacuum distillation operations.

Description

Of the conventional processes used to convert high-grade asphalt oil residues into higher-value hydrocarbons, one of these is to first subject these residues to a solvent deasphalting operation and then in a second phase, a hydrotreatment of deasphalted oils (DAO). This process (called process
EP-I) below, is illustrated by the following scheme I:
Scheme I
Treatment diagram I (EP-I)

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<tb><SEP> LIQUID <SEP> (c5 +)
<tb> RESID <SEP> ~ <SEP> EASPHZT
<tb><SEP> 2 \ sPTE
<tb>:: deasphalted oil
HDT: hydrotreatment
For the purpose of this specification, the term "petroleum residues" refers to heavy hydrocarbons having a density of less than 0.9218, derived from atmospheric distillation or under vacuum; this definition also covers heavy or extra-heavy crudes with a density of less than 0.9218, in particular Venezuelan crudes which are characterized in that they have a high content of asphaltic materials.

Deasphalting is an extraction carried out with saturated aliphatic hydrocarbons. In the extraction phase, the deasphalted oils (DAO) are obtained with a significantly reduced content of asphaltenes, metals and Conradson carbon, compared with the refined phase feed, which is mainly composed of asphalts
DAOs are exposed to hydrotreatment at relatively high temperatures and pressures, and in the presence of hydrogen and catalysts. Desulfurization, demetallation, decarbonization, denitrification and viscosity reduction are achieved in this phase.

 The main disadvantage of EP-I is the high production of asphalts with relatively low commercial value.

An alternative treatment for upgrading heavy residues containing asphaltic materials includes the phases of viscosity reduction, deasphalting and hydrotreatment. This process will be called processing diagrams II (EP-II) and is illustrated in the diagram
He following.

Diagram II
Treatment Diagram II (EP-II)

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<tb><SEP> Essence
<tb><SEP> Diesel
<tb> REsIW <SEP> REDUCT (<SEP> FROM <SEP> D
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HDT: hydrotreatment
The literature gives little information on this mode of treatment. U.S. Patent No. 3,132,088 which relates to this diagram claims heptane deasphalting, with a volume ratio of solvent loading of 2: 1, and a two-stage hydrotreatment with pressures of 7 to 14 MPa.

 The fundamental characteristic of the EP-I is the implementation of a first viscosity reduction phase, in which a moderate thermal disintegration of the charge takes place. The latter is heated to about 400-500BC and after phase separation and fractionation, gas, gasoline and gas oil fractions, and a reduced viscosity residue are obtained.

 The EP-II variant considerably reduces the production of asphalts and therefore improves the yield of liquid products which are much more interesting.

 The present invention provides a process for upgrading petroleum residues with a high asphaltic content, which process comprises the viscosity reduction, deasphalting and hydrotreatment phases. One of the aims of the present invention is to determine the influence of the viscosity reduction phase on the yield and quality of the liquid products obtained after the three phases of EP-II. Another aim is to determine how the quality of the deasphalted oils varies with the operating conditions in the deasphalting phase, such as the type of solvent used, the solvent / filler ratio, the temperature and the pressure.

Other objects are apparent from the described description of the present invention.

 The following is a detailed description of the conditions under which the three phases of the process for improving EP-II petroleum residues are carried out, and the properties of the products obtained are commented, with particular emphasis on the positive influence exerted by the initial phase of viscosity reduction on the results obtained.

Viscosity reduction phase
In the viscosity reduction phase, applied to the petroleum residue, the feedstock is introduced into an oven in which it reaches the reaction temperature and is then transferred to the reactor in a rising stream. The conditions under which the reactor operates are as follows
Pressure: 1.0-3.0 MPa
Temperature: 400-5000C
Length of stay: 10-60 minutes.

The yield of the products leaving the reactors normally varies in the following intervals
% in weight
Gas 1-3
C5 - 200 C 2-5
200 - 3500C 4-9
3500 + 83-93
At the output of the reactors, the products are sent to a primary "flash tower" where the separation between gas and liquid takes place.The liquid is transferred to a secondary "flash tower" where the gas, gasoline, the gas oil and the residue are separated, and the gases leaving the primary "flash tower", they are sent to a fractionation column where gas, gasoline and diesel are separated.

Deasphalting phase
Deasphalting is conducted directly with petroleum residues in EP-I, and with residues whose viscosity has been previously reduced, in EP-II.

When n-butane is used as the solvent, the pressure can be varied between 3.0 and 4.0 MPa, the temperature between 20 and 2000C and the weight ratio of the solvent to the load between 2: 1 and 12. 1. A significant increase in the production of CAD is achieved in
EP-II compared to the production that is obtained according to the EP-I diagram, this improvement being attributable to the initial phase of viscosity reduction.

Therefore, for an identical production of DAO, the deasphalting unit of EP-II must be smaller than that of EP-I, which implies a considerable reduction in investment and operating costs.

 The properties of the DAOs of EP-I and EP-II when using n-butane as the solvent are identical to each other, except for the concentration of the metals (Ni + V) and the viscosity which are in favor of the DAOs of EP-II . For an identical content of metals in both DAO, the deasphalting temperature, all other conditions being equal, is lower for EP-II, which is an advantage in favor of this diagram. Conversely; the amount of asphalt produced is much lower for EP-II than for EP-I, another advantage of EP-II if it is considered that asphalt is a product of relatively low commercial value.

When using n-pentane and n-hexane as solvents, the operation is carried out at a pressure which varies between 0.1 and 4.0 MPa, a temperature which varies between 20 and 2000C and a ratio of the solvent to the charge varies between 2: 1 and 12: 1. With both solvents; deasphalting under the conditions of EP-II gives a slightly lower yield of DAO than under the conditions of EP-I; however, the quality of the DAOs obtained in EP-II is much higher; because of the lower sulfur, metals (Ni + V) and Conradson carbon content, and because the viscosity is much lower. The fact that the metal content of the DAOs from EP-II may be lower than the metal content of DAO's
EP-I offers another advantage in the hydrotreatment phase, where the life of the catalysts depends in a binding measurement of the concentration of metals in the feedstock.

Hydroprocessing phase
This phase, common to EP-I and EP-II, is carried out by passing the feedstock in a fixed bed of "downstream co-current" type catalyst, containing metals of the groups tb and VlIIff with a specific surface area. pores from 150 to 300 m 2 / g and a pore volume of from 0.30 to 1.0 ml / g. The operating conditions can be varied in the following ranges
Pressure: 5.0-14.0 MPa
Temperature: 340-4200C
Space velocity 0.2-4 vol. 1 hr-1
H2- / load ratio 500-200 Nm3 / m3
The hydrotreating unit is fed with the DAOs obtained in the EP-I and EP-II diagrams.

 The products obtained with the two types of DAO have similar properties except the viscosity which is in favor of the product of EP-II, the reduction of the contents of sulfur, metals and nitrogen is similar for the DAOs of EP-I and EP-II, suggesting a very similar reactivity of the two charges. Liquid products (C5 +) obtained after hydrotreating can be used as low sulfur fuels OR for the production of light distillates or gasolines.

 The present invention is illustrated in detail by the following examples, given in a non-limiting manner.

Example 1
A heavy residue from a heavy crude of
Tia Juana, whose properties are shown in the first column of Table I, was subjected to
EP-I and EP-11.

The viscosity reduction phase of EP-II was conducted under the following conditions
Pressure of 1.5 MPa
Temperature: 4400C
Length of stay in the reactor: 15 minutes
The yields and properties of gasoline, gas oil and the reduced viscosity residue resulting from this phase are reproduced, respectively, in the second, third and fourth columns of Table I.

 The deasphalting of the residue under vacuum and the residue of reduced viscosity was carried out in a continuous pilot plant equipped with heating, stirring and pressure control means. N-Butane was used as the solvent, the temperature was 1200C, the pressure 3.3 MPa and the weight ratio of n-butane to the feed was 2: 1. The properties of the DAOs, in both cases, are reproduced in Table II. The higher DAO yield of EP-II (55.8% by weight relative to the deasphalting stage load) compared to the DAO of EP-I (38.7% by weight) is particularly remarkable. Table II that the yield of asphaltenes of EP-II is only 46.2% with reference to the residue at reduced viscosity (40.9% with respect to the residual charge), compared with the value of 61.3% obtained using EP-I.

Both DAOs were subjected to hydrotreatment at a temperature of 4000C, at a pressure of 10.2 MPa, at a space velocity of 2 vol.vol. -1 pm, a report
H2: feed of 800 Nm3 / m3, using a Co / Mo catalyst fixed on alumina, with 5.0% by weight of CoO, 16.2% by weight of MoO3 and a mean pore diameter 9.3 nm. The results are shown in Table III. For both diagrams, it can be seen that the yield is 98% and that the properties of the two products are similar except for the viscosity, which is lower for the EP-II product.

 The following diagrams 3 and 4 illustrate the mass balance corresponding to example 1 for EP-I and EP-II respectively e in these reports, one omitted the hydrogen which is used in the hydrotreatment phase.

Example 2
A vacuum residue from Tia Juana heavy crude, whose properties are indicated in the first column of Table I, was subjected to the viscosity reduction and deasphalting phases of EP-11.

 The viscosity reduction was carried out under the conditions described in Example 1, and the yields and properties of the products are shown in Table I.

Figure 3

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TABLE I
PROPERTIES OF THE LIQUID PRODUCTS OF THE PHASE
VISCOSITY REDUCTION
Residue of Dis Products
tillation under Screw residue
empty Gasoline Gasoline reduced cosity
Yield,% by weight 100 1.9 8.0 88.5
Density API 8.3 60.0 31.0 6.5
Density at 15.6 C / 15.6 C 1.012 0.739 0.870 1.025
Sulfur,% by weight 3.10 0.25 1.3Q 3.05
Nickel, ppm 81 - - 77
Vanadium, ppm 630 - - 643
Nitrogen, ppm 5161 - - 5061
Conradson Carbon,%
by weight 19.7 - 21.4
Asphaltenes,% by weight 11,5 - - 17,5
Kinematic viscosity,
10-6 m2 / s
at 37.8 C - - 6.3
to 600C - - - 18271
at 98.90C 4344 - - 644
ASTM initial temperature C - 87 160
Final temperature, C - 175 400
TABLE II
PROPERTIES OF DESASPHALTEES OILS (DAO)
Solvent: n-butane
Weight ratio
n-butane: 2: 1 charge
Temperature: 120 C
Pressure: 3.3 MPa
EP-I DAO DAO from EP-II
(DAO from (DAO from
from the residue under residue to
empty) reduced viscosity)
Yields in weight (1) 38.7 53.8
Density API 15.3 16.5
Density at 15.6 C / 15.6 C 0.964 0.956
Sulfur,% by weight 2.38 2.33
Nickel, ppm 8 6
Vanadium, ppm 68 58
Nitrogen, ppm 2615 2648
Conradson Carbon,% by weight 5.8 6.1
Asphaltenes,% by weight 0.05 0.09
Kinematic viscosity, 10-6 m2 / s
at 37.80C 15933990
at 600C 1860 197
at 98,9 C 158 28 (1) In relation to the load at the deasphalting stage
TABLE III
PROPERTIES OF HYDROTREATING PRODUCTS
Pressure: 10.2 MPa
Temperature: 4000C Space velocity 2 vol @ .h-1
H2 ratio: 800 Nm3 load: m3
EP-I EP-II DIAGRAM
Yield,% by weight (1) 98 98
Density API 19.0 20.8
Density at 15.60C / 15.60C 0.940 0.929
Sulfur,% by weight 0.58 0.56
Desulfurization,% by weight 75 76
Vanadium, ppm 4.6 4.2
Vanadium removal,%
by weight 93 93
Nitrogen, ppm 1890 1979
Denitrification,% by weight 28 25
Carbon Conradeon,% by weight 2,4 3,3
Reduction of the content
Conradson carbon,% by weight 60.5 45.3
Kinematic viscosity, 10-6 m2 / s
at 37.8 C 1450 316
at 93.3 C 41 16 (1) Refers to the charge at the hydrotreatment stage
The deasphalting of the residue of reduced viscosity was carried out in a continuous pilot plant, equipped with means of heating, stirring and pressure control. N-Butane was used as a solvent, the temperature was 1000 ° C. and the pressure 3.3 MPa.

The results are shown in Table IV. It should be noted that the metal content (Ni + V) obtained in the DAO is 71 ppm, which is of the same order of magnitude as the 76 ppm of metals found in the DAO produced by treatment of the vacuum residue of Tia Juana heavy crude (EP-I diagram) with nbutane, at a ratio of butane to feed of 2: 1, at a pressure of 3.3 MPa but at 1200C, as observed in Table II. However, the yield of DAO rises from 38.7%, when there is no prior reduction in viscosity, to 63.3% in the case of the present example, the two percentages referring to the feedstock load. deasphalting stage, which is a clear advantage of
EP-II on EP-I.

Example 3
A vacuum residue from Tia Juana heavy crude, whose properties are shown in the first column of Table I, was subjected to direct deasphalting (first phase of EPI) and to a viscosity reduction followed by deasphalting. (first and second phases of EP-II).

 The viscosity reduction phase of EP-II was carried out under the conditions described in Example 1, and the yields and properties of the products are shown in Table I.

The deasphalting of the residue under vacuum (first stage of EP-I) and the residue of reduced viscosity (second stage of EP-II) was carried out with n-pentane, with a n-pentane: charge ratio of 8: 1, at 200C and at atmospheric pressure. The results obtained and the properties of the DAOs are reproduced in Table V. It may be noted that the yield of DAO of EP-I is 79.0% against 74.3% in EP-TI, the two percentages referring to the charge at the deasphalting stage; however, the properties of the EP-II DAO are much higher than those of BP-I because of the lower carbon content
Conradson, the lowest viscosity and especially the lowest vanadium content (172 ppm vanadium for EP-I against 79 ppm for EP-II).

Example 4
A vacuum residue from Tia Juanat heavy crude oil, whose properties are reproduced in the first column of Table I, was subjected to direct deasphalting (first phase of EP-I) and to viscosity reduction followed by deasphalting ( first and second phases of EP-II) o
The viscosity reduction phase of EP II was carried out under the conditions described in Example 1, and the yields and properties of the products are shown in Table I.

 The deasphalting of the residue under vacuum (first stage of EP-I) and the residue of reduced viscosity (second stage of EP-II) was carried out with n-hexane at a n-hexane: charge ratio of 8: 1 to 200 ° C. and at atmospheric pressure. The results obtained and the properties of the DAOs are shown in Table VI. It should be noted that the DAO yield of EP-I is 86.5% and that of EP-II is 78.9%, these two percentages referring to the charge at the deasphalting stage, however, the properties of the EP-II DAOs are much higher than those of the BP-I DAOs, notably because of the lower Conradson carbon content, the lower viscosity and in particular because of the lower metal content (315 ppm vanadium for EP-I vs. 132 ppm vanadium for EP-II).

TABLE IV
PROPERTIES OF DESASPHALTEE OIL (DAO)
O-butane solvent
Weight ratio
n-butane load 2: 1
Temperature: 100 C
Pressure: 3.3 MPa
Yield,% by weight (1) 63.3
Density API 15.2
Density at 15.6 C / 15.6 C 0.965
Sulfur,% by weight 2.28
Nickel, ppm 7
Vanadium, ppm 64
Nitrogen, ppm 2782
Conradson Carbon,% by weight
Asphaltenes,% by weight 0.11
Kinematic viscosity,
10-6 m2 / s
at 60 C 138
at 98.90C 27.9 (1) Reported to load at the stage of DAO of EP-II
(DAO of the residue
viscosity deasphalting
scaled down)
TABLE V
PROPERTIES OF DESASPHALTEES OILS (DAO)
Solvent: n-pentane
Weight ratio
n-pentane: charge 8: 1
Temperature 200C
Atmospheric pressure
EP-I DAO DAO from EP-II
(DAO of the residue (DAO of the residue
vacuum) with viscosity
scaled down)
Yield,% by weight (1) 79.0 74.3
Density API 12.1 13.2
Density at 15.60C / 15.60C 0.985 0.978
Sulfur,% by weight 2.94 2.58
Vanadium, ppm 172 79
Conradson Carbon,% by weight 11.0 9.9
Asphaltenes,% by weight 0.36 0.45
Kinematic viscosity, 1 m2 / s
at 37.80C 7659 941
at 98.90C 386 88 (1) Relative to the load at the deasphalting stage
TABLE VI
PROPERTIES OF DESASPHALTEES OILS (DAO)
Solvent: n-hexane
Weight ratio
n-hexane: 8: 1 charge
Temperature 200C
Atmospheric pressure
EP-I DAO DAO from EP-II
(DAO of the residue (DAO of the residue
vacuum) with reduced viscosity
Yield,% by weight (1) 86.5 78.9
Density API 12.1 13.2
Density at 15,60Cj15,60C 0,985 0,978
Sulfur,% by weight 2.92 2.61
Vanadium, ppm 315 132
Conradson Carbon,% by weight 13.4 10.1
Asphaltenes,% by weight 1.31 0.90
Kinematic viscosity,
10- @ m2 / s
at 37.80C 5331 1002
at 98.90C 431 110 (1) Relative to the load at the deasphalting stage

Claims (6)

 1. A process for the treatment of petroleum residues with a density of less than 0.9218 (22 API), containing a high percentage of asphaltic materials, characterized in that it consists of a) subjecting the petroleum residues to an operation of  viscosity reduction under the following conditions  Pressure: 1.0-3.0 MPa  Temperature: 400-S000C  Length of stay in the reactor: 10-60 minutes  with obtaining fraction-s of gas, gasoline and  diesel fuel and a residue with reduced viscosity.  (DAO) and asphalt.  at 12: 1, so as to obtain a deasphalted oil  with a weight ratio of solvent to 2: 1  at a pressure ranging from 0 to 4.0 MPa,  saturated at a temperature ranging from 20 to 2000C,  deasphalting with aliphatic hydrocarbons (b) To subject the residue of reduced viscosity to an op-  light or gasoline.  in sulfur or as a base for obtaining distillates  can be used as low grade fuels  in order to obtain the liquid products (C5 +) which  H2 ratio: load: 500-2000 Nm3 / m3  Space velocity: 0.2-4 vol.vol.-1h-1  Temperature: 340-4200C  Pressure: 4.0-14.0 MPa  of the Periodic Table, under the following conditions  lysers containing Group VIb and VIII metals c) To subject the DAO to a hydrotreatment with cata  2. Method according to claim 1, characterized in that for the deasphalting phase of n-butane is used as a solvent, and in that the operating conditions vary in the following intervals Weight ratio: load 2: 1 to 8: 1 Temperature: 60-1500C Pressure: 3.0-4.0 MPa  3. Process according to claim 1, characterized in that n-pentane is used as solvent in the deasphalting phase, the conditions varying in the following intervals. Solvent weight ratio: 2: 1 to 12: 1 load Temperature: 20-200 C Pressure: Atmospheric to 4.0 MPa  4.Procédé according to claim 1, characterized in that in the deasphalting phase, n-hexane is used as a solvent and the conditions vary in the following ranges Solvent weight ratio: 2: 1 to 12: 1 load Temperature e 20-2000C Pressure: Atmospheric to 4.0 MPa  5. Process according to claim 1, characterized in that the catalyst used in the hydrotreating phase contains metals of groups VIb and VIII of the Periodic Table, fixed on alumina, silica or a silica-alumina mixture and has the following properties Specific surface 150-300 m2 / g Pore volume 0.30-1.00 ml / g Group VI metal content as oxide 10-20% by weight Group VIII metal content as oxide 2-5% by weight  6. Process according to one of claims 1 and 5, characterized in that the metal of group VIb is molybdenum and the metal of group VIII is cobalt.