Description:TECHNICAL FIELD OF THE INVENTION:
The present invention relates to the field of petroleum refining catalyst. Particularly, the present invention provides a sulfur resistant bimetallic catalyst for complete hydrogenation of polyaromatics in a feed stream, the catalyst comprising one or more metal salts and oxides, a support or structural promoter, an acidic zeolite, and a binder.
BACKGROUND OF THE INVENTION:
Mineral oil lubricants are derived from a diverse range of crude oil sources through various refining processes aimed at obtaining a lubricant base stock with appropriate boiling point, viscosity, pour point, viscosity index (VI) stability, volatility, and other essential characteristics. Typically, the base stock is produced by distilling the crude oil in atmospheric and vacuum distillation towers. Subsequent steps involve the removal of undesirable aromatic components through solvent refining, followed by dewaxing and several finishing procedures.
The selection of crude oil plays a crucial role in the quality of the resulting lubricant. Crudes with low hydrogen content or of asphaltic type are less favoured due to their tendency to yield a minimal quantity of acceptable lube stocks. This is primarily attributed to the significant presence of multi-ring aromatic components, which adversely affect thermal and light stability, color, and viscosity indices. To address these challenges, it is preferable to utilize paraffinic and naphthenic crude stocks. Even with paraffinic and naphthenic crude stocks, some feedstocks may contain polynuclear aromatics, necessitating aromatic treatment procedures. These treatments are essential to eliminate undesirable aromatic components and ensure the production of high-quality lubricants. Overall, the refining process is a carefully orchestrated sequence of steps designed to enhance the performance and characteristics of mineral oil lubricants, ensuring they meet industry standards and user requirements.
Conventional hydrotreating processes are pivotal in refining, widely adopted to achieve specified sulfur and aromatics levels. The focus on enhancing fuel quality extends beyond sulfur reduction, emphasizing the importance of minimizing aromatics. This dual objective not only meets environmental compliance by lowering sulfur but also boosts performance, improving combustion efficiency and overall fuel quality.
Common hydrotreating processes rely on Co-Mo and Ni-Mo sulfide catalysts, typically operating at temperatures exceeding 350 ? under high pressure. Nevertheless, these catalysts face limitations in overcoming the thermodynamic constraints of aromatic hydrogenation due to the preference for lower temperatures in achieving deep aromatic hydrogenation.
EP540123B discloses Composition of matter suitable as catalyst base in hydroprocessing comprising a crystalline aluminosilicate of the zeolite Y type, a binder and a dispersion of silica-alumina in an alumina matrix, wherein the composition comprises less than 25% by weight of the zeolite Y, more than 25% by weight of binder and at least 30% by weight of the dispersion. The invention further relates to hydroconversion catalysts and processes based on such hydroconversion catalysts.
CN101862670B discloses a carrier dry powder impregnation preparation method and application of a lubricating oil hydrogenation catalyst. The carrier dry powder impregnation preparation method is characterized in that: a mixture of a Y-shaped molecular sieve, amorphous silica-alumina, and alumina is adopted as a carrier of the catalyst, and the active ingredients of the catalyst consist of Pd and Pt. The catalyst is prepared by the method of impregnating carrier powder. Compared with the traditional preparation method of molding and impregnating successively, the preparation method for the catalyst decreases a one-time roasting process and protects the superficial area of the catalyst to the maximum, wherein the superficial area of the catalyst is 350 to 500 m<2>/g, and the pore volume is 0.5 to 0.8 ml/g.
WO2001080996A1 discloses a catalyst for the hydrogenation, hydroisomerisation, hydrocracking and/or hydrodesulfurisation, of hydrocarbon feedstocks, said catalyst consisting of a substantially binder free bead type support material obtained through a sol-gel method, and a catalytically active component selected from precious metals, the support comprising 5 to 50 wt. % of at least one molecular sieve material and 50 to 95 wt. % of silica-alumina.
Lately, noble metal catalysts have exhibited significant catalytic activity at low temperatures in deep hydrogenation. However, a notable drawback is their susceptibility to rapid deactivation, particularly when exposed to trace sulfur levels. Consequently, current hydrotreating processes involving noble metal catalysts necessitate ultra-deep hydrodesulfurization and multi-stage treatments to counteract sulfur-induced deactivation. Extensive research has focused on creating sulfur-resistant noble metal catalysts, with two prominent approaches for enhancing sulfur resistance. One avenue makes the noble metal particles more electron-deficient. This electron deficiency causes weaker sulfur-metal bonding and improves sulfur tolerance of the highly acidic supported noble metal catalyst.
SUMMARY OF THE INVENTION:
The present invention provides a sulfur-resistant bimetallic catalyst for the hydrogenation of polyaromatics comprising:
a. 0.1-2 wt% of metal salts and oxides;
b. 50-95 wt% of a support or structural promoter;
c. 5-25 wt% of a binder;and
d. 1-10 wt% w/w of an acidic zeolite,
wherein the catalyst is in an extrudate form.
DETAILED DESCRIPTION OF THE INVENTION:
For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in light of the remainder of the disclosure and understood as by a person of skill in the art.
The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below. The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.
The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. The term "at least one" is used to mean one or more and thus includes individual components as well as mixtures/combinations. Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps. The term “including” is used to mean “including but not limited to”. “including” and “including but not limited to” are used interchangeably.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described.
The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.
The term “LHSV” as defined herein is the liquid hourly space velocity, which is the ratio of liquid volume flow per hour to catalyst volume.
The term “Peptizing agent” as defined herein is an electrolyte that decreases the pH of the extrudate paste in relation to its point of zero charge breaking the agglomerates and improving the flow properties during extrusion. Peptizing agents typically have surfactant-like properties that help to disperse the solid particles evenly throughout the mixture. They work by reducing the surface tension between the solid particles and the surrounding liquid phase, thereby preventing agglomeration and promoting the formation of a stable suspension. This ensures that the catalyst extrudates have consistent composition and properties, leading to improved performance in catalytic processes. Common peptizing agents used in catalyst extrusion include organic compounds such as acids, bases, salts, and surfactants. These agents not only facilitate the extrusion process but also help in achieving the desired catalytic activity, selectivity, and stability of the final catalyst material.
In the present invention, diesel and lubricant properties have been emulated by creating a model feed comprising phenanthrene (polyaromatic) and dibenzothiophene (sulphur moiety) dissolved in dodecane solvent. All experiments were conducted in both batch and continuous modes. A noble metal-based catalyst was developed for the profound and selective hydrogenation of phenanthrene in the presence of 150 ppm sulfur at a low temperature of 220°C and at 70 bar H2 pressure. In-house, highly acidic amorphous alumina silicates were synthesized for the catalyst formulation, resulting in a remarkable 99% conversion without any dodecane cracking.
The present invention provides a sulfur-resistant bimetallic catalyst for the hydrogenation of polyaromatics, wherein the catalyst comprises:
a. 0.1-2 wt% of metal salts and oxides;
b. 50-95 wt% of a support or structural promoter;
c. 5-25 wt% of a binder;and
d. 1-10 wt% of an acidic zeolite,
wherein the catalyst is in an extrudate form.
In an embodiment of the present invention, the metals are selected from the group of Pt, Pd, Ni, Ru, Rh, Cu, Mo and W.
In an embodiment of the present invention, the metals are Platinum and Palladium, wherein Platinum is in a range of 0.1 to 1 wt% and Palladium is in a range of 0.1 to 1 wt%.
In an embodiment of the present invention, the support is selected from the group of Silica (SiO2), amorphous Alumina-Silica (Al2O3-SiO2), Alumina (Al2O3), Magnesium silicate (Talc), Zirconia (ZrO2), ZSM-5 or a combination thereof.
In an embodiment of the present invention, the support comprises amorphous Alumina-Silica (Al2O3-SiO2) present in a range of 70 to 90 wt% and Alumina (Al2O3) present in a range of 10 to 15 wt%.
In an embodiment of the present invention, the binder is selected from the group consisting of Pseudo boehmite, ludox silica, precipitated silica, Hydroxy propyl methyl cellulose.
In an embodiment of the present invention, the binder is Al2O3 and is present in a range of 10 to 15 wt%.
In an embodiment of the present invention, the acidic zeolite is selected from the group consisting of HY zeolite, mesoporous zeolite, beta zeolite, ZSM-5, ZSM-48, Mordenite.
In an embodiment of the present invention, the acidic zeolite is HY zeolite present in a range of 1 to 8 wt%.
In an embodiment of the present invention, the peptizing agent is selected from HNO3 and acetic acid.
In another embodiment of the present invention, the peptizing agent is HNO3.
In another embodiment of the present invention, the catalyst comprises Platinum in a range of 0.1-1 wt% and palladium in a range of 0.1-1 wt%, amorphous silica alumina (ASA) in a range of 70 to 90 wt% and alumina (Al2O3) in a range of 10 to 15 wt %, solid acid zeolite HY in a range of 1 to 8 wt%.
In another embodiment of the present invention, the catalyst conversion of polyaromatics is in a range of 99 to 100%. wherein a feed stream has 140 to 170 ppm sulphur impurities, preferably 150 to 154 ppm.
In another embodiment of the present invention, the catalyst is prepared by incipient impregnation method, or wet impregnation method.
The bimetallic catalyst composition is prepared in extrudate form using alumina as binder and used for the catalyst evaluation.
In an embodiment of the present invention, the feed stream comprises 3 wt.% Phenanthrene in the presence of 140 to 170 ppm of sulfur impurities.
In another embodiment of the present invention, the feed stream comprises 3 wt.% Phenanthrene in the presence of 150 to 160 ppm of sulfur impurities.
In another embodiment of the present invention, the feed stream comprises 3 wt.% Phenanthrene in the presence of 150 to 154 ppm of sulfur impurities.
In an embodiment of the present invention, alumina (Al2O3) is used both as a binder and a support.
In an embodiment of the present invention, pre-treatment of the catalyst is carried out at temperature in the range of 150 to 500°C and H2 pressure in the range of 2 to 15 bar.
In an embodiment of the present invention, catalyst pretreatment is done at temperature of 500 °C and under H2 pressure of 7 bars.
In an embodiment of the present invention, the hydrogenation reaction is carried out at temperature in the range of 150 - 250 °C; H2 pressure in the range of 60-150 bar; H2 flow 15-30 mL; LHSV in the range of 1-3 and Feed flow in the range of 0.33-0.66 mL/min.
EXAMPLES:
The disclosure will now be illustrated with working examples, which are intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure.
Example 1: Materials used in preparing the Hydrogenation catalyst in extrudate form.
The materials used in the preparation of the Hydrogenation catalyst in extrudate form is tabulated below in table. 1.
Table 1. List of materials used in preparing the Hydrogenation catalyst in extrudate form
S. No. List of Materials wt% ranges
1 Metal salts and their oxide:
Pt, Pd, Ni, Ru, Rh, Cu, Mo and W 0.1 - 2
2 Support/Structural Promoter:
Silica (SiO2), Alumina-Silica (Al2O3-SiO2), Alumina (Al2O3), Magnesium silicate (Talc), Zirconia (ZrO2), ZSM-5 50 – 95
3 Binder:
Pseudo boehmite, ludox silica, precipitated silica, Hydroxy propyl methyl cellulose 5 – 25
4. Acidic Zeolite:
HY zeolite, mesoporous zeolite, beta zeolite, ZSM-5, ZSM-48, Mordenite 1 – 10
5. Peptizing agent:
HNO3, acetic acid 1 – 25

Example 2: HP-CAT-1 catalyst.
HP-CAT-1, a monometallic catalyst prepared using 0.1-1 wt% Pt impregnated on Al2O3 alumina support. It is observed that, polyaromatic conversion was 57% only (table. 2).
Table 2. Hydrogenation of polyaromatics using HP-CAT-1 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-1-6H 7034 12685 13411 57.13
HP-CAT-1-12H 7034 12685 13411 57.13
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 H=Hour
Example 3: HP-CAT-2 catalyst.
HP-CAT-2, a bimetallic catalyst prepared using Pd (0.1 to 1 wt%) and Pt (0.1 to 1 wt%) impregnated on alumina (Al2O3) support. It is observed that, polyaromatic hydrogenation increased compared to earlier experiment whereas mono aromatics and diaromatics are still present in reaction mixture. All polyaromatics are converted to mono and di aromatic (table. 3).
Table 3. Hydrogenation of polyaromatics using HP-CAT-2 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-2-6H 17000 39000 3609 88.9
HP-CAT-2-12H 34000 89000 2295 92.9
HP-CAT-2-18H 45000 82000 205 99.3
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 H=Hour
Example 4: HP-CAT-3 catalyst.
HP-CAT-3 is a bimetallic catalyst prepared using Pt (0.1-1 %) and Pd (0.1-1%) impregnated on Al2O3 (95%) + HY (5%) Zeolite extrudes prepared in the ratio 95:5., using 0.1M HNO3 in 15-25 wt % as peptizing agent. The conversion of polyaromatic is 75.5% after 18 hours, but di and mono aromatic conversion is more as compared to earlier experiments (table. 4).
Table 4. Hydrogenation of polyaromatics using HP-CAT-3 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-3-6H 21000 12000 16000 51.0
HP-CAT-3-12H 27000 16000 11000 66.3
HP-CAT-3-18H 32000 18000 8000 75.5
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 H=Hour
Example 5: HP-Cat-4 catalyst.
HP-CAT-4 is a bimetallic catalyst prepared using Pt (0.1-1 %) and Pd (0.1-1%) impregnated on Al2O3 (95%) + ZSM-48 (5%) Zeolite extrudes prepared in the ratio 95:5. and, using 0.1M HNO3 in 15-25 wt % as peptizing agent. The conversion of polyaromatic is 99% after 18 hours, but di and mono aromatics are present in feed. While polyaromatic conversion reaches 99%, it's crucial to note that the presence of mono and di-aromatic compounds in the lube should ideally be minimized to parts per million (ppm) levels. Failure to maintain such low levels could compromise oxidation stability and color standards (table. 5).
Table 5. Hydrogenation of polyaromatics using HP-CAT-4 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-4-6H 50000 34000 9150 71
HP-CAT-4-12H 25000 3022 154 99
HP-CAT-4-18H 1.70 712 21 99
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 H=Hour
Example 6: HP-CAT-5 catalyst.
HP-CAT-5 is a bimetallic catalyst prepared using Pt (0.1-1 %) and Pd (0.1-1%) impregnated on amorphous silica alumina ASA support +Al2O3+ HY Zeolite extrudes prepared in the ratio ASA (50-90 wt%), HY (1-8 wt%) and Al2O3 (10-25wt%) using 0.1M HNO3 in 15-25 wt % as peptizing agent. The conversion of polyaromatic is 99% after 18 hours, but still monoaromatic content is high in product. While polyaromatic conversion reaches 99%, it's crucial to note that the presence of mono and di-aromatic compounds in the lube should ideally be minimized to parts per million (ppm) levels. Failure to maintain such low levels could compromise oxidation stability and colour standards. Here, mono aromatic is not in ppm or trace level (table. 6).
Table 6. Hydrogenation of polyaromatics using HP-CAT-5 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-5-6H 40000 5609 540 95
HP-CAT-5-18H 7000 223 59 99
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 H=Hour
Example 7: HP-CAT-6 catalyst.
HP-CAT-6 is a bimetallic catalyst prepared using Pt (0.1-1 %) and Pd (0.1-1%) impregnated on amorphous silica alumina (ASA) +Al2O3+ HY Zeolite extrudes prepared in the ratio ASA (50-90 wt%), HY (1-8 wt%) and Al2O3 (10-25wt%) using 0.1M HNO3 in 15-25 wt % as peptizing agent. In HP-CAT-6 amorphous silica alumina support content is more as compared to HP-CAT-5. Specifically, in HP-CAT-6: ASA is 88 wt% and Al2O3 is 10 % and HY zeolite is 2 %. The conversion of polyaromatic is 99% after 18 hours. This is complete hydrogenation of polyaromatic compound (table. 7). The HP-CAT-6 catalyst was evaluated in a continuous reactor and the results are tabulated in table. 8. Further, the result of Hydrogenation reaction using the HP-CAT-6 catalyst is shown in table. 9.
Table 7. Hydrogenation of polyaromatics using HP-CAT-6 catalyst
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-6-6H - - -
HP-CAT-6-12H - - -
HP-CAT-6-18H 1050 ND* ND 99
Reaction condition: Temp: 220 °C, P: 70 bars, rpm: 400 ND= Not determine from HPLC analysis or Negligible H=Hour
Table 8. Evaluation of HP-CAT-6 catalyst in a Continuous reactor
SAMPLE NAME MONO AROMATIC (PPM) DI AROMATIC (PPM) POLY AROMATIC (PPM) CONVERSION (%)
FEED 1912 384 32664 -
HP-CAT-6-6H 318 327 597 98.1
HP-CAT-6-12H ND 193 223 99.3
HP-CAT-6-18H ND 136 148 99.5
HP-CAT-6-24H ND 139 106 99.6
HP-CAT-6-30H ND 125 81 99.7
HP-CAT-6-36H ND 97 78 99.8
HP-CAT-6-42H 35 94 106 99.6
HP-CAT-6-48H ND 98 55 99.9
Reaction condition: Temp: 220 °C, P: 120 bar, 15 (ml/min) H2 flow, 1 LHSV (h-1), 0.033 Feed Flow (ml/min)
Table 9. Hydrogenation reaction results for HP-CAT-6 catalyst
S.No Properties Feed Product
1. Mono aromatic, ppm 1912 1055
2. Di aromatic, ppm 384 ND
3. Poly aromatic, ppm 32664 ND
4. Total Aromatic, wt% 3 -
5. Density, (g/cc) 0.7650 0.7592
6. Sulfur, ppm 150 - 154 12.3

, Claims:1. A sulfur-resistant bimetallic catalyst for the hydrogenation of polyaromatics, wherein the catalyst comprises:
a. 0.1-2 wt% of metal salts and oxides;
b. 50-95 wt% of a support or structural promoter;
c. 5-25 wt% of a binder; and
d. 1-10 wt% of an acidic zeolite,
wherein the catalyst is in an extrudate form.

2. The catalyst as claimed in claim 1, wherein the metals are selected from the group of Pt, Pd, Ni, Ru, Rh, Cu, Mo and W.

3. The catalyst as claimed in claim 2, wherein the metals are Platinum and Palladium, wherein Platinum is in a range of 0.1 to 1 wt% and Palladium is in a range of 0.1 to 1 wt%.

4. The catalyst as claimed in claim 1, wherein the support is selected from the group of Silica (SiO2), amorphous Alumina-Silica (Al2O3-SiO2), Alumina (Al2O3), Magnesium silicate (Talc), Zirconia (ZrO2), ZSM-5 or a combination thereof.

5. The catalyst as claimed in claim 4, wherein the support comprises amorphous Alumina-Silica (Al2O3-SiO2) present in a range of 70 to 90 wt% and Alumina (Al2O3) present in a range of 10 to 15 wt%.

6. The catalyst as claimed in claim 1, wherein the binder is selected from the group consisting of Pseudo boehmite, ludox silica, precipitated silica, Hydroxy propyl methyl cellulose.

7. The catalyst as claimed in claim 6, wherein the binder is Al2O3 and is present in a range of 10 to 15 wt%.

8. The catalyst as claimed in claim 1, wherein the acidic zeolite is selected from the group consisting of HY zeolite, mesoporous zeolite, beta zeolite, ZSM-5, ZSM-48, Mordenite.
9. The catalyst as claimed in claim 8, wherein the acidic zeolite is HY zeolite present in a range of 1 to 8 wt%.

10. The catalyst as claimed in claim 1, wherein the peptizing agent is selected from HNO3 and acetic acid.

11. The catalyst as claimed in claim 10, wherein the peptizing agent is HNO3.

12. The catalyst as claimed in claim 1, wherein the catalyst comprises Platinum in a range of 0.1-1 wt% and palladium in a range of 0.1-1 wt%, amorphous silica alumina (ASA) in a range of 70 to 90 wt% and alumina (Al2O3) in a range of 10 to 15 wt %, solid acid zeolite HY in a range of 1 to 8 wt%.

13. The catalyst as claimed in claim 12, wherein the catalyst conversion of polyaromatics is in a range of 99 to 100%, wherein a feed stream has 140 to 170 ppm sulphur impurities, preferably 150 to 154 ppm.

14. The catalyst as claimed in claim 1, wherein the catalyst is prepared by incipient impregnation method, or wet impregnation method.