DE2050940A1 - Solvent for deasphalting - Google Patents

Description

Solvent for deasphalting

The invention relates to a method and a contact device for separating a conveyed material containing a petroleum residue into asphalt and deasphalted oil. In the method according to the invention and by means of the device according to the invention, asphalt-containing material to be conveyed is treated by introducing high-molecular hydrocarbon solvent into a compact tower divided into compartments under the asphalt-containing material and by introducing a low-molecular hydrocarbon solvent above the asphalt-containing material to be conveyed. The high molecular weight solvent is an alkane hydrocarbon or an alkene hydrocarbon containing three to seven carbon atoms, and the low molecular weight solvent is an alkane hydrocarbon or an alkene hydrocarbon containing

109818 / 189t

2Q5Q94Q

contains two to six carbon atoms, the
low molecular weight solvent has at least one carbon atom less than the high molecular weight solvent ₀

The residue in petroleum or crude oil consists of
asphalt-like components and non-asphalt-like
Ingredients commonly referred to as asphalt and de-peeled oil. The separation of the deasphalted oil from the asphalt is generally achieved through the use of light hydrocarbon solvents, which preferably dissolve the deasphalted oil.The separation is carried out in contact devices in which the solvent and the petroleum residue are in countercurrent contact in several stages to be brought. A wide variety of devices are used for the separation or separation.
Impact towers, centrifuging contact device, bowl towers and mechanical stirring devices. This kind of
Separation is generally referred to as
Desajrphalting, decarbonising, de-resinising or de-peeling. The present process according to the invention can be cited above in connection with the most varied
Contact devices are carried out in which can be deasphalted.

It is known that deasphalting solvents derived from alkane hydrocarbons have heretofore been used
or alkene hydrocarbons and contain two to seven carbon atoms. The choice of solvent
for the corresponding deasphalting process
usually on the basis of deasphalting yield. , For example, propane is generally used when _s

1Q9Ö13 / 1891

a relatively low yield of a deasphalted oil having a low viscosity is required, while butane is generally used when higher yields of a deasphalted oil having a greater viscosity are required. Mixtures of propane and butane are used when corresponding deasphalting products are to be obtained which have both of the properties mentioned above. The change in the composition of the solvents used according to the deasphalting yield results from the properties of the light hydrocarbon solvent, ie _o if the density of the light hydrocarbon solvent is increased, then more deasphalted oil, which is progressively more aromatic and {has a higher molecular weight, in Solution, and as the density of the light hydrocarbon solvent is lowered, progressively deasphalted oil will go into solution, which is less aromatic and has a lower molecular weight. From this it can be seen that the density of the light hydrocarbon solvent must be controlled and regulated if a particular deasphalted oil is to be produced. It should be noted that the temperature cannot be varied without substantially changing the physical properties. When the temperature is decreased to the density of the light hydrocarbons like material solvent to increase in order to increase the yield of deasphalted "oil, then the viscosity of the oil residue phase increases rapidly, and thereby the mass transfer coefficient is decreased As a result, the viscosity of the oil residue layer is in fact so high that it approaches the solid state and extraction of the deasphalted oil becomes impossible. In order to overcome these difficulties, a wide variety of solutions were

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medium mixes and compositions used, where a pressure at the upper limit of the device and left constant has been used, you slight Hydrocarbon solvent mixture will normally be chosen so that the temperature is suitable for the desired yield a petroleum residue phase on deasphalting products which has a sufficiently low viscosity to allow a satisfactory amount of mass transfer will.

Although the change in the composition of the solvents was found to be an important factor this procedure has not proven to be entirely satisfactory. For example, it becomes pure If propane is used, temperatures will generally be obtained which are too low. If pure butane is used, temperatures are then generally obtained which are too high, the high temperature being limited to the level which can be generated economically by steam. Therefore, one went to mixtures of propane and Butane over, which also have not proven to be completely satisfactory, since the butane is constant being depleted by contamination in the stripped deasphalted oil and asphalt. Hence, maintenance is a certain fixed composition or mixture of light hydrocarbon solvents a continuing problem as the butane losses must be replenished and replaced. Big changes in the composition of the light hydrocarbon solvents caused by the change in the yield of deasphalting is determined, are made extremely difficult since large solvent losses in general the commercially available deasphalting units.

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20509A0

The invention was based on the object of an improved method for separating a petroleum residue containing material in asphalt and deasphalted oil and to develop a corresponding device.

The invention is based on the knowledge that alkane hydrocarbons, such as ethane, propane, butane, pentane, hexane and heptane as well as alkene hydrocarbons such as Athens, propene, butene, pentene, witches and heptene, which are normally used as solvents used in deasphalting petroleum residues, in addition to their well-known property of being high molecular weight Hydrocarbons based on molecular size back- | assign also high molecular weight aromatic compounds reject with preference of non-aromatic compounds (paraffins-naphthenes) of the same molecular weight. It was also found that the separation can be carried out very precisely if this easy hydrocarbon compounds among the appropriate ones Process conditions are used.

In the deasphalting process, it is common to use a steam coil _or a steam pipe coil on the upper part of the contact tower in order to generate a thermal reflux. By increasing the temperature of the |

Material at the top of the contact tower will lower its density and some of the hydrocarbon material is deposited and returned (rejected). A separate thermally induced reflux at the top of the column can be completely eliminated according to the method of the invention by using a high molecular weight solvent is introduced below the fed in conveyed material and a low molecular weight solvent above the fed in Conveyed material. In this way it is possible to have a reflux

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20509AO

along the entire height of the column itself, eliminating the need for a heating section is eliminated at the top of the column or tower. The heavy solvent is introduced in the bottom part of the tower, as it is desirable to get more material into solution at this point. A high molecular weight solvent is used to bring a larger amount of the material into solution. At the top of the tower is supposed to be the one Material will be rejected, deposited and recycled due to the introduction of the light solvent is delivered.

The device according to the invention for separating a conveyed material containing a petroleum residue into Asphalt and a deasphalted oil consists of a contact tower · This contact tower has the shape of a long one Column with an inner chamber. Several annular stator rings are attached to the inner chamber and form one Series of horizontally arranged compartments. A rotor with a series of blades is mounted in the inner chamber so that that each rotor blade is within a compartment. The conveyed goods are conveyed through a corresponding supply line fed into one of the compartments. For feeding the high molecular weight solvent into one of the compartments a device is arranged under the compartment into which the conveyed material is fed. The high molecular solvent consists of a hydrocarbon such as an alkane hydrocarbon or an alkene hydrocarbon, which have three to seven carbon atoms. To get a low molecular weight solvent in one of the compartments feed, a device is arranged above the compartment into which the conveyed material is fed. That low molecular weight solvent consists of a carbon

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hydrogen such as an alkane hydrocarbon substance or an alkene hydrocarbon and has two to six carbon atoms or mixtures thereof, wherein the low molecular weight solvent has at least one carbon atom less than the high molecular weight solvent. In this way, the high molecular weight solvent brings a relatively large proportion of the deasphalted Oil in the bottom part of the inner chamber in solution, and the low molecular weight solvent has due to its The lower density removes some of this deasphalted oil so that it creates a reflux at the top of the tower will.

According to the method according to the invention, a material to be conveyed containing a petroleum residue is in one Contact tower in asphalt and a deasphalted oil separated. The method of the invention is described in the following Steps carried out: The material to be conveyed is fed into the contact tower, a high-molecular solvent is in fed into one of the compartments located below the compartment in which the conveyed goods are fed, a low molecular weight solvent is fed into one of the compartments located above the compartment in which the material to be conveyed or the starting material is fed in. The light and heavy solvents have the molecular structures given above.

In the following description the method and the device according to the invention are explained in detail.

The contact tower 10 shown schematically in the accompanying figure is advantageously suitable for treatment a conveyed material containing a petroleum residue. The contact tower 10 has the shape of an elongated column and

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has an inner chamber 12 which is formed by a cylindrical wall 14, a bottom wall 16 and a top wall 18. A plurality of annular stator rings 20 are mounted in the inner chamber 12 on the cylindrical wall 14 and form a series of vertically arranged compartments 22 within the inner chamber 12. An upper calming grid 24 and a lower calming grid 26 are attached to the cylindrical wall Ik and support assemblies are attached to the calming grids. In the carrier arrangements 28, a rotor 30 is rotatably arranged, which consists of a shaft 32 and a series of rotor blades 3k which are attached along the shaft. Each of the rotor blades 3k is located in one of the compartments 22 _S so that the rotor blades 3k are arranged in the middle along the length of the compartments 22. A variable speed geared motor 36 is coupled to the shaft 32 to rotate the rotor blades 3k.

The conveyed material or starting material F is fed into one of the compartments 22 by means of a line 38 or initiated. A high molecular weight hydrocarbon solvent, labeled H, is placed in one of the compartments 22, which is located below the compartment into which the conveyed material F is fed. The high molecular one Solvent is introduced through the solvent line 40. A low molecular weight hydrocarbon solvent, which is denoted by L, is fed into one of the compartments 22, which is located above the compartment is located in which the conveyed F is introduced.

In order to allow flexibility in the generation of the reflux, a line system 42 is for the low molecular weight Solvent available, the three lines 43,

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44 and 46 for the low molecular weight solvent, each line having a valve 48 to To be able to set optimal procedural conditions · Having set an optimal procedural condition has been, two of the valves 48 are closed and the optimal line for the supply of the low molecular weight Solvent is put into operation.

The high molecular weight solvent H consists of alkane and / or alkene hydrocarbons with three to seven carbon atoms or mixtures thereof. The low molecular weight solvent consists of alkane and / or alkene-I hydrocarbons of two to six carbon atoms including mixtures thereof. The low molecular weight Solvent L has at least one carbon atom less than the high molecular weight solvent H.

A solution of solvent and deasphalted oil, designated F, is removed from the interior chamber via solution line 50 connected to top wall 18. The line 50 leads to a recovery system which is not shown here. A solvent-asphalt mix line 52 connected to the bottom wall ± 6 removes the asphalt \

mixture, which is designated by the letter M, to a recovery system, which is not shown here is.

According to the method according to the invention, the conveyed material F containing a crude oil residue is introduced into one of the compartments 22 of the inner chamber 12 in order to effect a separation of deasphalting _P the high molecular weight

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Solvent H is fed into one of the compartments 22 located at the bottom of the inner chamber 12 and under the compartment 22 in which the conveyed material F is introduced. The low molecular weight solvent L becomes introduced into one of the compartments 22 in the upper part of the inner chamber 12, this compartment being above the Compartment 22 is located, into which the conveyed material F is fed. The high molecular weight solvent H dissolves in everyone given temperature on more material than the low molecular weight solvent L. In this way is in the inner chamber 12 both stripped and rectified. During the stripping process, the oil is removed from the conveyed material F transferred into the high molecular weight solvent II. When rectifying, the oil is rising between the heavy solvent H and the downward flowing reflux exchanged. In this way it becomes high molecular weight Solvent H used in the asphalt stripping section of the contact tower 10 and the low molecular weight solvent L in the rectifying section for the deasphalted oil in the contact tower 10. This way of using the both solvents gives great flexibility in the total consumption of solvents and a much improved one Stripping or stripping and rectifying.

According to the method of the invention, the high molecular solvent H and the low molecular solvent Solvent L introduced into the corresponding parts of the contact tower 10 to optimal process conditions to achieve »The low molecular weight solvent is introduced into the upper part of the inner chamber 12, whereby Material is returned. The heavy solvent H is introduced into the bottom part of the inner chamber 12, to bring a relatively larger amount of material into solution.

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-I-

Various devices known to be used in Deasphalting are used, have not been shown in the present drawing. Such are for example a recovery device for the deasphalted oil, for the asphalt and the solvents as well as heating, cooling and pumping devices to maintain the desired operating conditions within of the contact tower 10 to reach.

From the above it can be seen that the method and the device for deasphalting by means of Solvent leads to a uniform dispersion in a multi-stage countercurrent extraction process, whereby the heavy solvent H has a relatively large proportion of the material at the bottom of the inner chamber 12 in solution brings.

Preferred embodiments of the method according to of the invention are given in the following examples,

EXAMPLE I
TABLE I.

KUWAIT RAW OIL 1,000 ° Ft VACUUM RESIDUE

Investigation results

specific Weight, ⁰ API 6.7

Viscosity SSU at 99 ° C 8420

Ramsbottom carbon residue, wt% 21

Nickel, ppm. 30th

Vanadium, ppm. 100

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Table I shows the physical properties of a sample obtained from the vacuum residue from a Kuwai crude consists. This petroleum residue sample was in a laboratory bomb Treated for deasphalting to the effect of high molecular weight and low molecular weight solvents to explain in detail if this is applied in accordance with the method according to the invention in the case of a petroleum backlog will.

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EXAMPLE II TABLE II

DEASPHALTATION WITH A LABORATORY CURGEN BOMB

Procedure

1. Stripping 2. Rectification

Injected material

Kuwait oil solvent oil vacuum residue phase from oper.

Operating conditions:

Solvent type

Solvent treatment VoI .- ^ fed on Vacuum residue

Bomb pressure, psig, bomb temperature, ⁰ C

1, ΟΟΟ ^υ F 65% C / 350

600

600

80% C- / 20% C _i

600 600

74

Solvent-free products Extracted back-
Oil wt.
asphalt 64.04 71 extra.
deasph.
oil reclaimed
oil - Exploit· - Vol .-% on fed
Vacuum residue 35.96 1.1 21.40 14.56 - Investigations: 1.0671 - Pregnancy, ⁰ API 18.3 - 20.3 15.3 spec. Weight, 6q6O ° F 0.9446 - 0.9321 0.9639 Viscosity SSU at 99 ° C 262.4 - 178 478 Ramsb. Carbon rticks fcand,
Wt%
Color, ASTM 3.16
5.50 - 1.69
6.0 Nickel, ppm. 0.7 0.2 Vanadium, ppm. 1.3 0.5 Softening point R&B ⁰ C - -

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Table II shows the operating conditions and the results of these laboratory tests. The procedure was carried out as follows:

1. A sample of vacuum residue was placed in the batch bomb given by Kuwaltöl.

2. High molecular weight solvent was introduced into the batch bomb to post-solvent treatment Table II, Procedure i. To perform.

3. The batch bomb was brought to operating temperature according to Table II, Procedure 1.

k. The contents of the batch bomb were agitated until equilibrium was reached.

5. The phases in the batch bomb were allowed to separate completely.

6. The extracted oil phase became from the batch bomb removed and the solvent stripped off.

7. The asphalt phase was removed from the batch bomb and the solvent stripped off.

8. The batch bomb was reloaded with a portion of the solvent-free extracted oil from step 6.

9. High molecular solvent got into the batch bomb given to achieve the same solvent-to-oil ratio as the extracted oil phase present in the bomb was after the asphalt phase was removed in stage 6.

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10. The batch bomb was loaded with low molecular weight solvent in order to carry out the solvent treatment according to table

11, procedure 2 ·.

11. Steps 3, 3 and 5 were repeated.

12. The deasphalted oil phase became from the batch bomb removed and the solvent stripped off

13. The rejected oil phase was removed from the batch bomb and the solvent stripped off.

The results of this procedure convincingly demonstrate the advantageous stripping of the high molecular weight solvent and the generation of reflux by the low molecular weight solvent. These effects of the two solvents are the basis of the present invention. It should be noted that reflux or rejection of the oil was achieved even when the sequence of operations was isothermal. With a single solvent, a reflux or a rejection of the oil in this order can not be achieved _o

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Claims (10)

PATENT CLAIMS (lj method for separating a conveyed material containing a petroleum residue into asphalt and a deasphalted oil in a contact device, characterized in that the conveyed material is fed into the contact device, a high molecular solvent is fed into the contact device at a level which is below the level of the feed of the conveyed material, the high molecular weight solvent consisting of alkane hydrocarbons or alkene hydrocarbons with three to seven carbon atoms or mixtures thereof, a low molecular weight solvent is fed into the contact device at a level which is arranged above the level of the feed of the conveyed material, the low molecular weight solvent from Alkane hydrocarbons and alkene hydrocarbons having two to seven carbon atoms or mixtures thereof and at least one carbon atom less than the high molecular weight solvent, and that the För dergut and the solvents are stirred and mixed in the contact device, whereby the high molecular weight solvent brings a relatively large proportion of the deasphalted oil in the bottom part of the contact device in solution and the low molecular weight solvent brings a relatively small proportion of the deasphalted oil in the upper part of the contact device in solution. 2. The method according to claim 1, characterized in that the asphalt and the deasphalted oil are withdrawn from the contact device together with the solvents. 109818/1891 3. The method according to claim 1, characterized in that that the inner part of the contact device is heated, in order to generate a temperature gradient running perpendicular to the device within the contact device. k, The method according to claim 1, characterized in that the high molecular weight solvent has a molecular weight of 52 to 100 and the low molecular weight solvent has a molecular weight of Ik to k2 less than the molecular weight of the high molecular weight solvent. 5. The method according to claim 1, characterized in that that the solvent in the contact device is recycled Ä. 6. The method according to claim 1, characterized in that the method is carried out in a contact tower, the one inner chamber with a stripping area and has a rectification area, the Pördorgut is fed into the inner chamber, the high molecular weight Solvent in the stripping area, the low molecular weight solvent in the electifying area and the conveyed material and stirring the solvents in the inner chamber. 7. The method according to claim 1, characterized in that the method is carried out in a contact tower, which contains an inner chamber which has a series of vertically arranged compartments and a rotor with a Series of leaves within each compartment are arranged, wherein the conveyed is fed into one of the compartments, the high molecular weight solvent in one of the compartments is fed, which is below the 109818/1891 The compartment into which the conveyed material is fed is located, the low molecular weight solvent in one of the compartments is fed, which is above the compartment into which the conveyed material is fed, and the conveyed material and the solvents are mixed in the inner chamber. 8. Contact device for separating a conveyed material containing a petroleum residue in asphalt and a deasphalted oil, characterized by an elongated column (10) with an inner chamber (12), a device (38) for feeding the conveyed material into the inner chamber, a device (40) for feeding in a high molecular weight Hydrocarbon solvent into the inner chamber below the level of the feed being fed in, the high molecular weight hydrocarbon solvents made from alkane hydrocarbons and / or alkene hydrocarbons having three to seven carbon atoms or mixtures thereof consists, a device (43) for feeding a low molecular weight hydrocarbon solvent into the inner Chamber above the level of the infeed of the conveyed material, the low molecular weight solvent being made up of alkane hydrocarbons and / or alkene hydrocarbons having two to seven carbon atoms or mixtures thereof and wherein the low molecular weight solvent has at least one carbon atom less than the high molecular weight Solvent, and a device (30) for mixing the conveyed material and the solvent, whereby the high molecular weight Hydrocarbon solvents a relative large proportion of the deasphalted (ils on the bottom of the inner chamber brings into solution and the low molecular weight Hydrocarbon solvent has a relatively low proportion of the deasplmltierton (ils on the upper part of the inner chamber brings into solution. 109818/1891 9. Contact device according to claim 8, characterized in that the high molecular weight solvent has a molecular weight of 52 to 100 and the low molecular weight solvent has a molecular weight of 14 to k2 lower than the molecular weight of the high molecular weight solvent. 10. Contact device according to claim 8, characterized by a contact tower with a plurality of annular stator rings (20) which are mounted in the inner chamber and form a series of vertically arranged compartments ^ 22), a rotor (30) with a shaft (32), which is rotatably arranged in the inner chamber and to which a plurality of rotor blades (34) are attached, so that each rotor blade is located within a compartment, the device for feeding the conveyed material (38) into one of the compartments, the device for feeding the high molecular weight hydrocarbon solvent (40) leads into one of the compartments which is located below the compartment into which the conveyed material is introduced, and wherein the device for feeding the low molecular weight hydrocarbon solvent (43 »44, 46) leads into one of the compartments which is above the Is arranged compartment into which the conveyed material is introduced. 109818/1891 10. Blank page