DESC:FIELD
The present disclosure relates to a process for production of bitumen grade materials and distillates.
DEFINITION
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Middle distillates refer to petroleum products obtained in the “middle” boiling range from about 180°C to 370°C during the process of crude oil distillation.
Pitch refers to a black or dark brown colored residue formed during the process of crude oil distillation or upgradation of heavier hydrocarbons.
Penetration value- Penetration value determines the hardness or softness of bitumen by measuring the distance in millimeter to which a standard loaded needle will penetrate vertically in five seconds while the temperature of the bitumen sample is maintained at 25 oC.
If penetration value is N, Distance penetrated = (N/10) mm.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Refinery processes lead to the formation of vacuum residue towards the end of vacuum distillation process, which is blown in a bitumen blowing unit to make bitumen or further thermally cracked in a visbreaking unit to produce fuel oil. The visbreaking reaction mainly leads to formation of middle distillates such as naphtha, gas oil and visbroken tar.
The visbroken tar does not meet some of the major properties such as penetration, kinematic viscosity, softening point and ductility, in order to be categorized as bitumen grade material. This is mixed with visbroken gas oils and cutter stocks to make fuel oil. The thermal cracking done in a visbreaking unit leads to formation of coke which should be controlled to meet the fuel oil specification. Catalytic visbreaking process is known in the art. This process increases the conversion of vacuum residue to produce increased distillates maintaining the quality of fuel oil. However, this process does not produce the tar that fulfils the criteria for achieving the bitumen properties.
In order to make bitumen, vacuum residue is blown in a bitumen blowing unit. This process, however, does not produce lighter hydrocarbon products and leads to formation of only bitumen which is low value products compared to middle distillates.
There is, therefore, felt a need for a simple and economical process for obtaining bitumen grade product from vacuum residue along with middle distillates, that mitigate the drawbacks mentioned hereinabove.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a simple and effective process for obtaining bitumen grade material from vacuum residue.
Yet another object of the present disclosure is to provide a process for obtaining bitumen grade material with reduced amount of coke formation.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure provides a process for producing bitumen grade materials having a penetration value in the range of 35 to 80, a kinematic viscosity in the range of 250 to 400 centistokes, a softening point in the range of 40 oC to 50 oC and a ductility in the range of 25-75 from vacuum residue. The process comprises obtaining a vacuum residue stream from hydrocarbon feed. The vacuum residue stream is hydrocracked in a mild hydrocracking unit (MHC) (4) at a predetermined conditions for a predetermined time period by using hydrogen gas in the presence of a catalyst to obtain a product mixture comprising a gaseous products, middle distillate, a vacuum gas oil and the bitumen grade materials. The product mixture is fractionated to obtain the separated bitumen grade materials (10) and other distillates.
In an embodiment, the vacuum residue is obtained by separating a hydrocarbon feed (1) in an atmospheric distillation unit (ADU) (2) to obtain an overhead stream and an atmospheric residue stream. The atmospheric residue stream is fractionated in a vacuum distillation unit (VDU) (3) to obtain a vacuum distillate and a vacuum residue stream.
The predetermined conditions include a temperature in the range of 350 oC to 450 oC, a pressure in the range of 1 bar to 80 bar, liquid hourly space velocity (LHSV) in the range of 0.5 h-1 to 12 h-1. The predetermined time period is in the range of 5 minutes to 120 minutes.
The product mixture comprises bitumen grade material in an amount in the range of 55 wt.% to 75 wt.%.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic representation for the flow-path of the process in accordance with the present disclosure.

List of Reference Numerals
Hydrocarbon feed 1
Atmospheric Distillation Unit (ADU) 2
Vacuum Distillation Unit (VDU) 3
Mild Hydrocracking unit (MDH) 4
Catalyst 5
Hydrogen 6
Fractionation unit 7
Middle distillates 8
Bitumen grade material 10

DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
Conventionally the vacuum residue can be thermally cracked in the presence or absence of catalyst in a visbreaking unit to obtain less viscous heavy material such as visbroken tar. This heavy material itself does not find an application; however, it can be blended with other lighter distillates to produce fuel oil, which is well known in the art.
Vacuum residue from vacuum distillation column bottoms can also be processed in bitumen blowing unit to make various grades of bitumen. However, high value products such as lighter distillates cannot be produced by these processes. In order to produce lighter distillates, the vacuum residue can be cracked thermally or catalytically similar to visbreaking process. The bitumen grade material obtained by cracking the vacuum residue should satisfy certain properties such as penetration, kinematic viscosity, softening point and ductility, in order to be categorized as bitumen grade material. The simultaneous production of both distillates as well as bitumen from a single process could lead to flexibility in operations based on demand.
The present disclosure provides a process for producing bitumen grade material in addition to other distillates. The process results in comparatively higher yields of bitumen grade materials with reduced coke formation.
The present disclosure provides a process for obtaining bitumen grade materials having a penetration value in the range of 35 to 80, a kinematic viscosity in the range of 250 to 400 centistokes, a softening point in the range of 40 oC to 50 oC and a ductility in the range of 25-75 from vacuum residue.
The process is described in details as:
? Obtaining a vacuum residue stream from hydrocarbon feed.
? Further, the vacuum residue stream is hydrocracked in a mild hydrocracking unit (MHC) (4) at a predetermined conditions for a predetermined time period by using hydrogen gas in the presence of a catalyst to obtain a product mixture comprising a gaseous products, middle distillate, a vacuum gas oil and the bitumen materials.
In accordance with one embodiment of the present disclosure, the vacuum residue is obtained by following steps:
? In a first step, a hydrocarbon feed (1) is separated in an atmospheric distillation unit (ADU) (2) to obtain an overhead stream and an atmospheric residue stream.
? Next, the atmospheric residue is fractionated in a vacuum distillation unit (VDU) (3) to obtain a vacuum distillate and a vacuum residue stream.
In accordance with the embodiment of the present disclosure, the predetermined conditions include a temperature in the range of 350 oC to 450 oC, a pressure in the range of 1 bar to 80 bar, liquid hourly space velocity (LHSV) in the range of 0.5 h-1 to 12 h-1. In an exemplary embodiment, the temperature is 410 oC, the pressure is 15 bar.
The predetermined time period is in the range of 5 minutes to 120 minutes. In an exemplary embodiment, the time period is 20 mins.
In accordance with the present disclosure, the catalyst is introduced in at least one form selected from the group consisting of colloidal dispersed form, slurry phase dispersed form, extrudate form, water soluble form and oil soluble catalyst form. In an exemplary embodiment, the catalyst is in the form of slurry phase dispersed catalyst.
In accordance with the embodiments of the present disclosure, the catalyst comprises at least one transition metal selected from the group consisting of iron, cobalt, nickel, molybdenum, tungsten and tin.
In accordance with the embodiments of the present disclosure, the amount of catalyst is in the range of 10 ppm to 15000 ppm. In an embodiment the amount of catalyst is in the range of 50 ppm to 2000 ppm. In an exemplary embodiment, the amount of catalyst is 500 ppm.
In accordance with the embodiments of the present disclosure, the volume ratio at normal condition of hydrogen to the vacuum residue stream is in the range of 50 to 1000. In an embodiment, the volume ratio of ratio of hydrogen to the vacuum residue stream is in the range of 100 to 800. In an exemplary embodiment, the volume ratio is 400. The gaseous products in the hydrocracked product mixture can be at least one alkane selected from the group consisting of methane, ethane, propane and butane.
The mild hydrocracking unit (MHC) comprises bubble column reactors and ebullated bed reactors. In an exemplary embodiment, the mild hydrocracking unit bubble column reactor.
The product mixture is fractionated to obtain the separated bitumen grade materials (10) and other distillates.
The distillate yield from hydrocracking is in the range of 25 wt% - 45 wt%.
In accordance with the embodiments of the present disclosure, the product mixture comprises bitumen grade material in an amount in the range of 55 wt% to 75 wt%. In an exemplary embodiment, the amount is 66 wt.%
In accordance with the embodiments of the present disclosure, the bitumen grade materials have a penetration value in the range of 35 to 80, a kinematic viscosity in the range of 250 to 400 centistokes, a softening point in the range of 40 oC to 50 oC and a ductility in the range of 25-75 from vacuum residue. In an exemplary embodiment, the penetration value is 58, the kinematic viscosity is 344.4 centistokes, the softening point is 49.6 oC and ductility is 59.
In accordance with the embodiments of the present disclosure, the distillate yield from hydrocracking is in the range of 25 wt% - 45 wt%.
In accordance with the embodiments of the present disclosure, the process can be a continuous process or a batch process.
The bitumen grade material is tested for properties such as penetration, kinematic viscosity, softening point and ductility and found desired quality.
In one embodiment, Figure 1 illustrates a schematic representation for the flow-path of the process in accordance with the present disclosure. A hydrocarbon tank is connected to an atmospheric distillation unit (2) for distilling the hydrocarbon mixture. The atmospheric distillation unit (2) is connected to a vacuum distillation unit (3) for fractionating heavier fraction mixture (bottom fraction) from the atmospheric distillation unit (2) to obtain a vacuum distillate and a vacuum residue stream. The vacuum distillation unit (3) is connected to a mild hydrocracking unit (4) for hydrocracking the vacuum residue stream obtained from the vacuum distillation unit (3). The mild hydrocracking unit (4) is connected to a catalyst storage tank (5) and a hydrogen storage tank (6). The catalyst storage tank (5) is configured to store catalyst and the hydrogen storage tank (6) is configured to store hydrogen for hydrocracking reaction.
In an embodiment, the hydrogen storage tank (6) is connected to a hydrogen generating unit.
The mild hydrocracking unit (4) is further attached to a fractionation unit (7) for fractionating product mixture obtained after the hydrocracking reaction.
The present disclosure provides a simple and efficient process for obtaining bitumen grade material from vacuum residue. The process results in relatively higher amount of distillates and bitumen grade materials in comparison to the conventional processes along with reduction in the coke formation.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment 1: Process for production of bitumen grade material by hydrocracking of Basrah vacuum residue:

The hydrocarbon feed consist of about 86 wt% of hydrocarbons boiling above 540 °C which was distilled in ADU followed fractionating VDU to obtain vacuum residue.
Firstly, a mild hydrocracking unit was loaded with 1000 gram of Basrah vacuum residue along with catalyst concentration of 500 ppm of molybdenum oil soluble catalyst. Then the reactor was purged with nitrogen and later was pressurized with Hydrogen of 15 bar. volume ratio of hydrogen to vacuum residue is 400. The mixture of vacuum residue, catalyst and hydrogen gas was heated to 410 oC under constant stirring of 500 rpm. Hydrocracking reactions started when the reactor temperature reaches 350 oC in presence of hydrogen. The reaction was carried out for a period of 20 minutes maintaining the reaction temperature at 410 oC to form the product mixture comprising gaseous products, middle distillates, VGO, and bitumen. After 20 minutes, the product mixture was cooled by circulating chilled water to bring down the temperature below 30 oC. The gaseous products were analyzed using Gas Chromatograph for its composition. The liquid sample was collected and analyzed in GC-SIMDIST as per ASTM D-7169. The product mixture was fractionated in Minipotstill apparatus to get the individual product cuts. The bitumen grade material cut boiling above 540 oC was further characterized for bitumen properties.

Table 1: Composition of the product mixture
Vacuum reside Hydrocracking at mild severity
Yields (Wt%)
Gas 3.8
LPG 0.3
Naphtha (<180 oC) 3.5
Distillates (180-370 oC) 4.2
VGO (370-540 oC) 14 22.5
Unconverted Residue (540 oC+), Bitumen range material 86 65.6
Conversion % 35

Table 1 shows the comparison of yields of different cuts resulting from hydrocracking of Basrah vacuum residue at milder conditions. Mild hydrocracking resulted in increasing distillate (C5 – 540 oC) cut yields of 30.2% and the bitumen grade material cut yield of 66.5% resulting from mild hydrocracking process meets desired bitumen specifications. At low severity of hydrocracking conditions, the conversion obtained in this process is about 35 wt%.

.

Table 2: Properties of Bitumen grade materials
For Feed Vacuum residue Bitumen grade materials from the mild hydrocracking process
Property
Penetration at 25oC, Min 27 58
Kinematic Viscosity, cSt, Min 428.8 344.3
Softening Point, oC, Min 47 49.6
Ductility, Min - 59

Table 2 shows the different properties of bitumen resulting from the bitumen grade material boiling above 540 oC. The bottom fraction is characterized for important bitumen properties such as softening point, ductility, penetration point and kinematic viscosity
From the above experiments, it is concluded that the properties of bitumen grade materials are in closely matching with the viscosity grade bitumen.
It is further to be observed upon blending with lighter fractions, the properties of bitumen can be varied between viscosity grade 10 – viscosity grade 40 grade bitumen specifications.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for production of distillates and bitumen grade materials from vacuum residue that:
? is simple and efficient;
? provides significant amount of bitumen grade material; and
? reduces coke formation.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure, as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A process for producing bitumen grade materials having a penetration value in the range of 35 to 80, a kinematic viscosity in the range of 250 to 400 centistokes, a softening point in the range of 40 oC to 50 oC and a ductility in the range of 25-75, said process comprising the following steps:
a) obtaining a vacuum residue stream;;
b) hydrocracking said vacuum residue stream in a mild hydrocracking unit (MHC) (4) at a pre-determined conditions for a pre-determined time period by using hydrogen gas in the presence of a catalyst to obtain a product mixture comprising a gaseous products, middle distillate, a vacuum gas oil and bitumen materials;
c) fractionating said product mixture to obtain said bitumen grade materials (10).

2. The process as claimed in claim 1, wherein said vacuum residue stream is obtained by following steps:
a) separating a hydrocarbon feed in an atmospheric distillation unit (ADU) (2) to obtain an overhead stream and an atmospheric residue stream; and
b) fractionating said atmospheric residue stream in a vacuum distillation unit (VDU) (3) to obtain a vacuum distillate and a vacuum residue stream;
3. The process as claimed in claim 1, wherein said pre-determined conditions include a temperature in the range of 350 oC to 450 oC, a pressure in the range of 1 bar to 80 bar, liquid hourly space velocity (LHSV) in the range of 0.5 h-1 to 12 h-1.

4. The process as claimed in claim 1, wherein said pre-determined time period is in the range of 5 minutes to 120 minutes.

5. The process as claimed in claim 1 wherein the catalyst dosage rate is in the range of 10 ppm to 15,000 ppm.
6. The process as claimed in claim 1, wherein said catalyst is introduced in at least one form selected from the group consisting of colloidal dispersed form, slurry phase dispersed form, extrudate form, water soluble form and oil soluble catalyst form.

7. The process as claimed in claim 1, wherein said catalyst comprises at least one metal selected from the group consisting of molybdenum, iron, nickel, cobalt, and tungsten.

8. The process as claimed in claim 1, wherein the weight ratio of hydrogen to said vacuum residue stream is in the range of 50 to 1000.

9. The process as claimed in claim 1, wherein said mild hydrocracking unit comprises bubble column reactors and ebullated bed reactors.

10. The process as claimed in claim 1, wherein said product mixture comprises bitumen grade materials in an amount in the range of 55 wt.% to 75 wt.%.
Dated this 4th Day of July, 2020

MOHAN RAJKUMAR DEWAN
of R.K. DEWAN & COMPANY
IN/PA-25
APPLICANT’S PATENT ATTORNEY