A method for producing lubricating base oil by isomerization dewaxing-hydrofining combined process

Abstract

The application discloses a method for producing lubricating oil base oil by using an isodewaxing-hydrofining combined process, which comprises an isodewaxing process catalyzed by an isodewaxing catalyst and a supplementary refining process using a hydrofining catalyst, wherein the isodewaxing catalyst is a single-atom noble metal catalyst supported on a carrier, the refining catalyst is a single-atom noble metal catalyst supported on a carrier, and the carrier is selected from a molecular sieve carrier or an alumina carrier; and the noble metal is selected from one or more of platinum, palladium, ruthenium, rhodium, iridium, gold or silver. Since the single-atom catalyst has the characteristic that metal atoms are highly dispersed in the form of single atoms, the atomic utilization rate reaches 100%, the method can realize efficient catalysis under the condition of a lower noble metal usage amount, and the high-efficiency production of lubricating oil base oil is realized while the usage amount of noble metal is reduced. The single-atom catalyst still exhibits the catalytic performance superior to that of the current commercial nanocrystal catalyst under the condition that the usage amount of noble metal is reduced by about 50% than that of the existing catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the application of single-atom catalyst in the production of lubricating oil base oil, and belongs to the technical field of petroleum chemical industry. BACKGROUND

[0002] The isomerization dewaxing-hydrofining combined process for producing lubricating oil base oil can generate isomeric alkanes by isomerization reaction of straight-chain alkanes with high condensation point in waxy raw material oil including diesel, AGO, VGO, white oil, hydrocracking tail oil and lubricating oil fraction, so as to reduce the pour point of the product and maintain a high yield of lubricating oil base oil. The process has the advantages of great flexibility of raw materials, high base oil yield and high value of by-products.

[0003] The active components of the catalysts used in the isomerization dewaxing and hydrofining two-stage process are noble metals including Pt, Pd, Ru and Rh. In recent years, the price of noble metals has soared, and the investment in noble metals has gradually become a heavy burden for enterprises. Therefore, how to produce high-quality lubricating oil base oil with high efficiency and low noble metal content is of great practical significance to current chemical production enterprises. SUMMARY

[0004] The present application discloses a method for producing lubricating oil base oil by isomerization dewaxing-hydrofining combined process, which comprises an isomerization dewaxing process catalyzed by an isomerization dewaxing catalyst and a supplemental refining process using a refining catalyst. The isomerization dewaxing catalyst is a single-atom noble metal catalyst supported on a carrier, and the refining catalyst is a single-atom noble metal catalyst supported on a carrier. The carrier is selected from a molecular sieve or an alumina carrier. The noble metal is selected from one or more of platinum, palladium, ruthenium, rhodium, iridium, gold or silver.

[0005] The noble metal is preferably platinum, palladium, ruthenium or rhodium.

[0006] The carrier is preferably a molecular sieve or an alumina carrier, such as a TON-type molecular sieve, an MTT-type molecular sieve or γ-Al2O3.

[0007] The single-atom noble metal catalyst supported on the carrier means that the noble metal is supported on the carrier in a single-atom site state. The content of the noble metal is 0.01-2wt%, preferably 0.05-0.5wt%, based on the total weight of the catalyst.

[0008] The isomerization dewaxing catalyst is preferably a supported single-atom platinum catalyst, wherein the carrier is selected from a molecular sieve or alumina, and is further preferably a single-atom platinum metal supported on a ZSM-22-type molecular sieve or a ZSM-23-type molecular sieve.

[0009] The preferred refined catalyst is a supported monatomic platinum palladium catalyst, wherein the support is selected from a molecular sieve or alumina, further preferably a monatomic platinum and palladium metal supported on an alumina support, preferably gamma-Al2O3.

[0010] The preparation steps of the supported monatomic catalyst of the present application are as follows:

[0011] Step A: loading a noble metal precursor onto a support according to the designed loading amount to form a noble metal monatomic catalyst precursor;

[0012] Step B: treating the noble metal monatomic catalyst precursor with a nitrogen-containing compound, wherein the precursor is a noble metal monatomic catalyst precursor;

[0013] Step C: calcining the catalyst precursor to obtain a noble metal monatomic catalyst.

[0014] The noble metal precursor is a soluble noble metal inorganic salt, or a noble metal organic salt, or a noble metal complex. Preferably, a nitrate salt, a chloride salt, a sulfate salt, an acetate salt, an acetylacetone salt, a chloride complex, an ammonia complex, or a phosphorus complex, preferably chloroplatinic acid, chloroplatinic acid salt, chloropalladic acid, chloropalladic acid salt, platinum acetylacetone, palladium acetylacetone, platinum acetate, palladium acetate, platinum nitrate, palladium nitrate, and ammonia complexes of the above compounds. The soluble means soluble in water or alcohol, wherein the alcohol is methanol or ethanol; the noble metal is selected from one or more of platinum, palladium, ruthenium, rhodium, iridium, gold, or silver, preferably the noble metal is selected from platinum or palladium, or a mixture of the two.

[0015] The support is selected from a molecular sieve or alumina, further selected from a TON-type molecular sieve, a MTT-type molecular sieve, or gamma-Al2O3, preferably a ZSM-22-type molecular sieve, a ZSM-23-type molecular sieve, or gamma-Al2O3.

[0016] The noble metal is dispersed on the support in a monatomic site state, and the loading amount of the noble metal on the support is 0.01-2wt% (relative to the total weight of the catalyst), preferably 0.05-0.5wt%.

[0017] The nitrogen-containing compound is NH3, dimethylformamide, urea, C 1-20 alkane amine, C 2-20 olefin amine, C 1-20 alkane diamine, C 1-20 alkane triamine, C 6-20 aromatic amine; preferably NH3, dimethylformamide, urea, C 1-6 alkane amine, C 1-6 alkane diamine, C 6-20Aromatic amine, more preferably NH3, ethylenediamine, triethylamine, n-butylamine or dimethylformamide; aqueous or alcoholic solution of nitrogen-containing compound can be used, wherein the alcoholic solution is methanol or ethanol solution.

[0018] In step A, loading can be carried out by any known means in the art, including impregnation, adsorption, ion exchange, incipient wetness, precipitation, spray drying and the like, and the present application uses impregnation method for loading. The carrier is mixed with the noble metal salt solution to obtain the noble metal loaded catalyst precursor by separation;

[0019] In step B, the catalyst precursor is soaked or washed with the nitrogen-containing compound, and then solid-liquid separation is carried out to obtain the solid catalyst precursor;

[0020] Before step C, the solid catalyst precursor can be dried as needed, and the calcination is carried out at 200-600℃, preferably 300-500℃.

[0021] The hydrogen isomerization agent is prepared using platinum metal, and the carrier uses ZSM-22 and ZSM-23 molecular sieves.

[0022] The supplemental refining agent is prepared using platinum and palladium metals, and using γ-Al2O3 carrier.

[0023] Glossary:

[0024] TON type molecular sieve is a crystalline material with one-dimensional 10-membered ring channel. Examples of TON framework type molecular sieves include ISI-1, KZ-2, NU-10, Theta-1 and ZSM-22, and the present application implements ZSM-22 molecular sieve.

[0025] MTT type molecular sieve is a crystalline material with one-dimensional five-membered ring, six-membered ring and ten-membered ring parallel pore structure. Examples of MTT framework type molecular sieves include KZ-1, ISI-4, EU-13 and ZSM-23, and the present application implements ZSM-23 molecular sieve.

[0026] Complexes are also known as complexes, including complexes of noble metals or transition metals with ligands, common ligands include halogen (fluorine, chlorine, bromine, iodine), nitro, nitroso, cyanide, ammonia, water molecules or organic groups, common complexes include chloride complexes, ammonia complexes, cyanide complexes, etc., including chloroplatinic acid, chloroplatinic acid salt, chloroplatinic acid hydrate. Please refer to "Handbook of Noble Metal Compounds and Complexes Synthesis" (Yujianmin, 2009, Chemical Industry Press).

[0027] Beneficial effects:

[0028] Due to the single-atom catalyst has the characteristics of highly dispersed metal atoms in the form of single atoms, the atom utilization rate reaches 100%, this method can realize efficient catalysis under the condition of low noble metal usage, realize efficient production of lubricating oil base oil while reducing the usage of noble metal. Using the single-atom catalyst still shows similar or even slightly higher than the commercial nanocrystalline catalyst under the condition of reducing the amount of noble metal by nearly 50%, indicating that the single-atom catalyst has more excellent catalytic performance, which can effectively reduce the usage of noble metal. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 : Aberration-corrected transmission electron microscopy image of isomerization catalyst in Example 1, the bright spots in the figure are Pt single atoms

[0030] Figure 2 : Aberration-corrected transmission electron microscopy image of refining catalyst in Example 1, the bright spots in the figure are Pt atoms and / or Pd single atoms DETAILED EMBODIMENTS

[0031] Example 1

[0032] Isomerization catalyst preparation: 100 g of shaped clover ZSM-22 carrier was weighed, and an equal volume of chloroplatinic acid was impregnated (Pt loading was 0.2%). The impregnated catalyst precursor was dried at 120°C overnight (12 h). The dried sample was soaked in 2wt% ammonia water for one day (24 h), and the obtained catalyst was separated by solid-liquid separation, dried at 120°C overnight (12 h) and calcined at 400°C for 1 h to obtain the isomerization catalyst.

[0033] Refining catalyst preparation: 100 g of shaped clover γ-Al2O3 carrier was weighed, and an equal volume of chloroplatinic acid and sodium chloropalladate was impregnated (Pt loading was 0.1%; Pd loading was 0.15%, and the rest was the carrier). The impregnated catalyst precursor was dried at 120°C overnight (12 h). The dried sample was soaked in 2wt% ammonia water for one day, and the obtained catalyst was separated by solid-liquid separation, dried at 120°C overnight (12 h) and calcined at 400°C for 1 h to obtain the refining catalyst.

[0034] Example 2

[0035] Isomerization catalyst preparation: 100 g of shaped clover ZSM-23 carrier was weighed, and an equal volume of chloroplatinic acid was impregnated (Pt loading was 0.2%). The impregnated catalyst precursor was dried at 120°C overnight (12 h). The dried sample was soaked in 2wt% ammonia water for one day (24 h), and the obtained catalyst was separated by solid-liquid separation, dried at 120°C overnight and calcined at 400°C for 1 h to obtain the isomerization catalyst.

[0036] Refined catalyst preparation: 100 g of shaped clover γ-AI2O3 support was impregnated with equal volume of chloroplatinic acid and sodium chloropalladate (Pt loading of 0.1 %; Pd loading of 0.15 %, rest being the support). The impregnated catalyst precursor was dried at 120 °C for overnight (12 h). The dried sample was soaked in 2 wt% ammonia water for one day (24 h). The obtained catalyst after solid-liquid separation was dried at 120 °C for overnight (12 h) and calcined at 400 °C for 1 h to obtain the refined catalyst.

[0037] Example 3

[0038] Isomerization catalyst preparation: 100 g of ZSM-22 powder support was impregnated with equal volume of chloroplatinic acid (Pt loading of 0.25 %). The impregnated catalyst precursor was dried at 120 °C for overnight (12 h). The dried sample was soaked in 2 wt% ammonia water for one day (24 h). The powder isomerization catalyst was dried at 120 °C for overnight and calcined at 400 °C for 1 h. The catalyst was shaped into clover shaped catalyst by extrusion before testing.

[0039] Refined catalyst preparation: 100 g of shaped clover γ-AI2O3 support was impregnated with equal volume of chloroplatinic acid and sodium chloropalladate (Pt loading of 0.1 %; Pd loading of 0.15 %, rest being the support). The impregnated catalyst precursor was dried at 120 °C for overnight (12 h). The dried sample was soaked in 2 wt% ammonia water for one day (24 h). The obtained catalyst after solid-liquid separation was dried at 120 °C for overnight and calcined at 400 °C for 1 h to obtain the refined catalyst.

[0040] Comparative Example 1

[0041] Commercial isomerization catalyst (Pt loading of 0.35 %, support being clover shaped ZSM-22 support) and commercial refined catalyst (Pt loading of 0.2 %; Pd loading of 0.3 %, support being cylindrical γ-AI2O3) were used for catalytic evaluation. The noble metals in the purchased commercial catalysts were in the form of nanoparticles.

[0042] Test experiments and data

[0043] Isomerization and hydrogenation performance test:

[0044] Isomerization and hydrogenation performance test was performed using the following hydrocracking tail oil (feed oil), oil composition is shown in Table 1.

[0045] Test experiments were performed on a dual fixed bed reactor in series, where the first reactor was packed with isomerization catalyst and the second reactor was packed with refined catalyst. The reaction temperature of the first reactor and the second reactor was 350 °C and 220 °C, respectively, the reaction pressure was 16 MPa, and the space velocity was 1 h -1, the volume ratio of hydrogen oil (hydrogen and raw oil) is 1000:1, after isomerization hydrofining, different fraction products are collected, see the test results in Table 2. Among them, the two-stage catalyst is activated for 30h under hydrogen atmosphere before catalytic evaluation.

[0046]

[0047]

[0048] Table 1: Properties of hydrocracking tail oil (raw oil)

[0049] The present application tests different catalysts of Examples 1-3 and Comparative Example 1 under the same conditions, and the evaluation results are as follows:

[0050]

[0051] Table 2: Test data

[0052] Conclusion:

[0053] Compared with nano catalysts, the present application shows that the single-atom catalyst has similar or even higher catalytic performance under the condition of low noble metal usage (noble metal usage is reduced by nearly 50%), lower use cost, and high industrial application prospect.

Claims

1. A method of producing a lubricating oil base stock in an isodewaxiing- hydrofmishing combined process, the method comprising an isodewaxing process catalyzed using an isodewaxing catalyst and a supplemental finishing process using a hydrofmishing catalyst, wherein, The isodewaxing catalyst is a single-atom noble metal catalyst supported on a carrier, and the hydrofining catalyst is a single-atom noble metal catalyst supported on a carrier, the carrier being selected from a molecular sieve carrier or an alumina carrier; The content of the noble metal is 0.01-2 wt% based on the total weight of the catalyst, and the noble metal is supported on the carrier in a single-atom site state; The isodewaxing catalyst is a single-atom platinum catalyst supported on a carrier, and the hydrofining catalyst is a single-atom platinum-palladium catalyst supported on a carrier.

2. The method of claim 1, wherein, The content of the noble metal is 0.05-0.5 wt% based on the total weight of the catalyst; the molecular sieve is selected from a TON-type molecular sieve or a MTT-type molecular sieve, and the alumina carrier is γ-Al2O3.

3. The method of claim 1 or 2, wherein the isodewaxing catalyst is a single-atom platinum metal supported on a ZSM-22-type molecular sieve, a ZSM-23 molecular sieve or a ZSM-48-type molecular sieve.

4. The method of claim 1 or 2, wherein, The hydrofining catalyst is a single-atom platinum and palladium metal supported on a γ-Al2O3 carrier.

5. The method of claim 1 or 2, wherein the molecular sieve or alumina carrier used is an industrial shaped carrier.

6. The method of claim 5, wherein, The carrier is a powder carrier, which is shaped into a strip after being loaded with the noble metal.

7. A method for preparing the single-atom supported catalyst for isodewaxing-hydrofining combined process for preparing lubricating oil base oil according to any one of claims 1-6, the steps of which are as follows: Step A: loading a noble metal precursor on a carrier according to the designed loading amount to form a noble metal single-atom catalyst precursor; Step B: treating the noble metal single-atom catalyst precursor with a nitrogen-containing compound, the precursor being a noble metal single-atom catalyst precursor; Step C: calcining the catalyst precursor to obtain a noble metal single-atom catalyst, wherein the isodewaxing catalyst is a single-atom platinum catalyst supported on a carrier, and the hydrofining catalyst is a single-atom platinum-palladium catalyst supported on a carrier; The noble metal precursor for preparing the isodewaxing catalyst is selected from chloroplatinic acid, chloroplatinic acid salt, platinum acetylacetonate, platinum acetate, platinum nitrate and ammonia complexes of the above compounds; the noble metal precursor for preparing the hydrofining catalyst is selected from chloroplatinic acid, chloroplatinic acid salt, chloropalladic acid, chloropalladic acid salt, platinum acetylacetonate, palladium acetylacetonate, platinum acetate, palladium acetate, platinum nitrate, palladium nitrate and ammonia complexes of the above compounds; The carrier is selected from a molecular sieve or alumina, The noble metal is dispersed on the carrier in a single-atom site state, The nitrogen-containing compound is NH3, dimethylformamide, urea, C 1-20 alkane amines, C 2-20 alkene amines, C 1-20 alkane diamines, C 1-20 alkane triamines, or C 6-20 aromatic amines.

8. The method of claim 7, wherein, In step A, the noble metal is loaded using impregnation, adsorption, ion exchange, incipient wetness impregnation, precipitation or spray drying.

9. The method of claim 8, wherein in step A, the loading is performed using impregnation.

10. The method of claim 7, wherein in step B, the catalyst precursor is soaked or rinsed with a nitrogen-containing compound, and then a solid catalyst precursor is obtained; the nitrogen-containing compound is NH3, dimethylformamide, urea, C 1-6 alkane amine, C 1-6 alkane diamine, or C 6-20 aromatic amine.

11. The method of claim 10, wherein, The nitrogen-containing compound is NH3, ethylenediamine, triethylamine, n-butylamine or dimethylformamide.

12. The method of claim 10, wherein, An aqueous solution or an alcoholic solution of the nitrogen-containing compound is used, wherein the alcoholic solution is a methanol or ethanol solution.

13. The method of any one of claims 7-12, wherein before step C, the solid catalyst precursor is dried, and the calcination is performed at 200-600℃.

14. The method of claim 13, wherein, The calcination is performed at 300-500℃.

15. The method of any one of claims 7-12, wherein, The isodewaxing catalyst is prepared using platinum metal, and the support uses ZSM-22 or ZSM-23 molecular sieve; the hydrofining catalyst is prepared using platinum and palladium metal, and the support uses a γ-Al2O3 carrier.

16. A method for producing lubricating base oil by an isodewaxing-hydrofining combined process, the method comprising an isodewaxing process catalyzed by an isodewaxing catalyst and a supplemental refining process using a hydrofining catalyst, wherein, The isodewaxing catalyst is a single-atom noble metal catalyst supported on a carrier, and the hydrofining catalyst is a single-atom noble metal catalyst supported on a carrier, and the carrier is selected from a molecular sieve or an alumina carrier; the content of noble metal is 0.01-2 wt% based on the total weight of the catalyst, and the noble metal is supported on the carrier in the form of single-atom sites; The isodewaxing catalyst is a supported single-atom platinum catalyst, and the hydrofining catalyst is a supported single-atom platinum-palladium catalyst; The isodewaxing catalyst and the hydrofining catalyst are prepared by the method of any one of claims 7-15.

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