A method for regeneration of a solid acid catalyst for long chain alkylaromatics synthesis

Abstract

A regeneration method of a solid acid catalyst for long-chain alkyl aromatic hydrocarbon synthesis, characterized in that the deactivated solid acid catalyst is heated to 300-460 DEG C at a heating rate of 1-15 DEG C / min in a hydrogen atmosphere and treated at the temperature and under the conditions of 1.5-3 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 h, wherein the solid acid catalyst contains a Y-type zeolite loaded with a metal component having hydrogenolysis performance, the unit cell of the Y-type zeolite is 2.448-2.457 nm, the ratio of mesopore volume to total pore volume is 0.15-0.29, and the hydrogenolysis performance metal accounts for 0.15-5 wt% of the solid acid catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to a regeneration method of a solid acid catalyst, and more particularly to a regeneration method of a solid acid catalyst loaded with a hydrogenolysis performance metal. BACKGROUND

[0002] Linear alkylbenzene obtained by alkylation of benzene and long chain olefin is an important chemical intermediate for synthesis of washing products, and the intermediate can be obtained by sulfonation, neutralization and other reactions to obtain anionic surfactant-alkyl benzene sulfonate with excellent performance. The alkylation reaction of benzene and long chain olefin lays the foundation for the synthesis of washing products industry.

[0003] At present, 83% of the global linear alkylbenzene production adopts HF process, 9% adopts AlCl3 process, and 8% adopts Detal process.

[0004] Both HF process and AlCl3 process have the disadvantages of high environmental pollution, serious equipment corrosion, difficult product separation, and large cost investment. Detal process is a solid acid process developed by UOP Company of the United States and CEPSA Petroleum Company of Spain, and was industrialized in the mid-1990s. Detal process uses fluorine-containing amorphous silicon aluminum catalyst. Due to the problems of fluorine loss in the running process, discontinuity of alkylation reaction and catalyst regeneration process, high running cost and frequent regeneration, its promotion and development are limited to a certain extent. Therefore, the green and environmentally friendly solid acid alkylation process technology is the development trend.

[0005] In the research of synthesizing linear alkylbenzene from benzene and long chain olefin by solid acid catalyst, molecular sieve and heteropoly acid type solid acid catalyst are mostly used. However, the problems of easy deactivation and short single cycle life have not been effectively solved.

[0006] Current researches are mostly focused on catalytic materials or optimization of process flow to improve single cycle operation time, and there are many problems such as poor effect of catalytic materials, frequent operation of process flow and high cost. For example, CN1043524C discloses a method for benzene alkylation with fluorinated silicon aluminum and linear mono-olefin, in which benzene and C6 to C 20 The benzene is alkylated by contacting linear mono-olefin with a catalyst comprising silica and alumina in a weight ratio of 1:1 to 9:1 and fluorinated silicon aluminum having a fluorine content of 1 to 6 wt%, the method has an olefin conversion rate of 98%, a selectivity of 85% or better for the generated mono-alkylbenzene, and a linearity of at least 90% for the generated mono-alkylbenzene. The conversion rate of the method for olefin is still low, and there is the problem of environmental pollution caused by fluorine ion loss.

[0007] CN101535221B discloses a method for preparing alkylbenzene with low benzene to olefin ratio and low heavy substance generation on a solid acid catalyst. The method uses small crystal, acidic FAU molecular sieve as catalyst under alkylation conditions.

[0008] CN111514924A discloses a catalytic synthesis method of long-chain alkyl aromatic hydrocarbon, which comprises: first, feeding raw aromatic hydrocarbon into a fixed-bed alkylation reactor to fill the reactor; then, feeding raw aromatic hydrocarbon, raw C6-C 24 The mixture of long-chain olefin and additive long-chain alkyl aromatic hydrocarbon solvent or long-chain alkane solvent is input into the fixed-bed reactor to contact with the SBA-15 type mesoporous molecular sieve alkylation solid acid catalyst, and the aromatic hydrocarbon and long-chain olefin alkylation reaction is carried out to generate the product long-chain alkyl aromatic hydrocarbon; part of the alkylation reactor effluent is recycled to the reactor as a circulating fluid, and the other part is separated from the excess raw materials and product effluent fluid in a distillation separation system.

[0009] US5648579A discloses a method for alkylation reaction of benzene and 1-dodecene by pulse feeding. In the method, benzene is always fed, and the olefin is stopped feeding every certain time, so as to realize pulse feeding, the molar ratio of benzene and olefin is between 8 and 20, the carbon number of linear olefin ranges from 10 to 14, and the pulse feeding interval time is 10-60 minutes.

[0010] At present, the regeneration technology of alkylation catalysts mostly adopts solvent elution, which has many problems such as poor regeneration effect, frequent operation of regeneration process and high cost. SUMMARY

[0011] The purpose of the present application is to provide a regeneration method for a specific solid acid catalyst for long-chain alkyl aromatic hydrocarbon synthesis, which can efficiently and stably restore the activity of the catalyst.

[0012] In order to achieve the above-mentioned purpose, the present application provides a regeneration method for a solid acid catalyst for long-chain alkyl aromatic hydrocarbon synthesis, characterized in that the deactivated solid acid catalyst is heated to 300-460℃ at a hydrogen heating rate of 5-15℃ / min in a hydrogen atmosphere and treated at this temperature and 1.5-3MPa, hydrogen flow rate of 150-500mL / min / g for at least 5h, wherein the solid acid catalyst contains Y-type zeolite loaded with hydrogenolysis metal component, the unit cell of the Y-type zeolite is 2.448-2.457nm, the ratio of mesopore volume to total pore volume is 0.15-0.29, and the hydrogenolysis metal component accounts for 0.15-5wt% of the solid acid catalyst.

[0013] The inventors have found that the solid acid catalyst obtained by loading metal components with hydrogenolysis activity on a solid acid with specific physical and chemical characteristics has longer catalyst life and linear aromatic selectivity when used in long-chain alkyl aromatic hydrocarbon synthesis reactions. The catalyst obtained by loading metal components with hydrogenolysis activity on a solid acid with specific physical and chemical characteristics can maintain good selectivity and catalyst life after multiple regenerations when specific hydrogen regeneration conditions are selected.

[0014] In the present application, the content of the solid acid Y-type zeolite is 40-95 wt% based on the solid acid catalyst. It has been found that alkylation reactions can be catalyzed not only by B acid but also by L acid. Therefore, controlling the unit cell of Y-type zeolite can ensure the integrity of the crystal structure and sufficient B acid active sites for the reaction. Therefore, in the present application, the unit cell of the Y-type zeolite is 2.448-2.457 nm, preferably 2.452-2.455 nm.

[0015] It has also been found that the deactivation of aromatic hydrocarbon and long-chain olefin alkylation reactions is caused by the blockage of catalyst pores by heavy alkyl aromatic hydrocarbons generated during the reaction. Since heavy alkyl aromatic hydrocarbons are the key to catalyst deactivation, a certain proportion of mesopores can promote the timely diffusion of macromolecules such as heavy alkyl aromatic hydrocarbons from the pores, delaying catalyst coking. Therefore, in the present application, the ratio of mesopore volume to total pore volume of the Y-type zeolite is 0.15-0.29, and the preferred ratio of mesopore volume to total pore volume is 0.18-0.26. The mesopore volume and total pore volume are determined by static low-temperature nitrogen adsorption capacity (BET). The determination is performed using an ASAP2420 adsorber from Micromeritics, USA. The determination process is as follows: the sample is first dried at 110°C for 2 h to remove surface water, then a certain amount of sample is weighed and placed in a degassing unit, vacuumed to a vacuum degree of less than 1.33 Pa, treated at 90°C for 1 h, then heated to 330°C for 9-10 h. The sample is subjected to nitrogen adsorption-desorption testing under liquid nitrogen cooling conditions to obtain the adsorption-desorption curve, and the specific surface area and pore volume are calculated by the BET formula.

[0016] The metal component with hydrogenolysis performance accounts for 0.15-5 wt% of the solid acid catalyst, preferably 0.2-2 wt%, and more preferably 0.4-1 wt%. The metal component with hydrogenolysis performance is loaded on the Y-type zeolite and has strong synergistic catalysis with B acid sites, which has better alkylation activity and selectivity under the reaction conditions of the present application. The metal component with hydrogenolysis performance is selected from one or more of Group VIB, VIIB and VIII metals. The Group VIII metal is selected from one or more of Pt, Pd and Ru, and Pt is preferred. Pt can produce synergistic effects with B acid and also serve as a source of part of the L acid center, thereby improving catalyst life.

[0017] In the present application, the solid acid catalyst further comprises an inorganic oxide matrix. The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide.

[0018] In the present application, preferably, the conditions of the regeneration process are as follows: heating at a hydrogen heating rate of 1-10℃ / min to 340-420℃ and treating at this temperature and 2.0-2.8MPa, hydrogen flow rate of 150-400mL / min / g for at least 5h. In one embodiment of the present application, the deactivated solid acid catalyst is heated in a hydrogen atmosphere at a hydrogen heating rate of 2-8℃ / min to 340-360℃ and treated at this temperature and 2.0-2.6MPa, hydrogen flow rate of 200-400mL / min / g for 6h.

[0019] The deactivation of the solid acid catalyst in the alkylation reaction of aromatics and long-chain olefins is caused by the blocking of the pore channels of the solid acid catalyst by the heavy alkylated aromatics generated in the reaction. The hydrogen regeneration can dissociate hydrogen into hydrogen atoms in a hydrogen environment by using noble metals, and then the hydrogen atoms can react with the carbon deposition components to restore the activity of the catalyst. The present application can regenerate the catalyst with special cell constants and specific mesopore ratios of Y-type zeolite as the solid acid catalyst by matching the parameters of temperature, pressure, hydrogen flow rate, heating rate and constant temperature time, and the regenerated catalyst can still maintain the initial life of the solid acid catalyst and high LAB selectivity and 2-LAB selectivity.

[0020] The regeneration method provided by the present application is suitable for the regeneration of solid acid catalysts with specific physical and chemical parameters in the alkylation reaction of long-chain olefins and aromatics. The long-chain olefins include one or more of C 10 ~C 14 , such as decene, undecene, dodecene, tridecene, tetradecene and their respective isomers. The aromatics are one or more of monocyclic or polycyclic aromatic hydrocarbons, such as benzene, naphthalene, toluene, xylene, diethylbenzene, trimethylbenzene, triethylbenzene, tetramethylbenzene and their respective isomers. Preferably, the aromatics are monocyclic or bicyclic aromatic hydrocarbons, and more preferably the aromatics are benzene or toluene. The alkylation reaction of long-chain olefins and aromatics is carried out at a temperature of 70-280℃, a pressure of 1.5-4MPa and a raw material mass space velocity of 1-20.

[0021] The regeneration method provided by the present application can be implemented in various reaction devices, such as fluidized bed, fixed bed and slurry bed. In one embodiment of the present application, the regeneration operation is carried out in a fixed bed. The regeneration method provided by the present application can effectively remove the coking components of the solid acid catalyst for specific solid acid catalysts, thereby ensuring the long-term operation of the catalyst.

[0022] Based on the regeneration method, the application further provides a long-chain alkyl aromatic hydrocarbon synthesis method, characterized by comprising a long-chain alkene and aromatic hydrocarbon alkylation reaction process and a solid acid catalyst regeneration process. In the long-chain alkene and aromatic hydrocarbon alkylation reaction process, the alkylation reaction conditions are 90-180℃ of temperature, 2.0-4.5 MPa of pressure, and 1-30 of raw material mass space velocity. The solid acid catalyst is Y zeolite loaded with metal components having hydrogenolysis performance. The unit cell of the Y zeolite is 2.448-2.457 nm, the ratio of mesopore volume to total pore volume is 0.15-0.29, and the metal components having hydrogenolysis performance account for 0.2-2 wt% of the solid acid catalyst. The regeneration process of the solid acid catalyst is to heat the solid acid catalyst to 300-460℃ at a heating rate of 5-15℃ / min in a hydrogen atmosphere and treat the solid acid catalyst at the temperature and 1.5-3 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 h.

[0023] In the application, the performance of the alkylation reaction is evaluated by using the two indexes of cycle life and product distribution. The cycle life is based on the conversion rate of olefins being greater than 99%, the product distribution is based on linear alkylbenzene (LAB) and 2-LAB, and the products are analyzed by gas chromatography. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values claimed herein are not to be understood as being limited to the exact values recited as implicitly disclosed by the above description. Ranges can be expressed as from one value in the range to another value in the range. When, in this specification, values of ranges are expressed as from the lower limit, through the upper limit, in some embodiments each intermediate value of the interval between the lower and the upper limit are also specifically disclosed. Each intermediate value of this interval is discretely and independently disclosed in addition to the interval itself. For values and steps which are expressed as about a given value, the term is intended to encompass both values approximating the given value (both higher and lower), along with the given value itself.

[0025] The application will be described in detail below with examples. It should be understood that the specific embodiments described herein are merely illustrative and are not to be taken as limiting the application.

[0026] Example 1

[0027] This example is used to illustrate the alkylation reaction-regeneration method of the solid acid catalyst of the application.

[0028] The solid acid catalyst is prepared by mixing Y zeolite (purchased from the Catalyst Branch of SINOPEC) and alumina at a weight ratio of 4:1, uniformly, and then loading 0.4 wt% of Pt by impregnation. The unit cell constant of the Y zeolite is 2.453 nm, and the ratio of mesopore volume to total pore volume is 0.22. The obtained solid acid catalyst is numbered as A1.

[0029] The specific physicochemical properties of A1 and the hydrogen regeneration conditions are shown in Table 1.

[0030] The alkylation reaction was carried out in a fixed bed high pressure micro-reaction experimental device. The raw materials of the alkylation reaction were benzene and n-dodecene, 5 g of alkylation catalyst A1 was loaded in a fixed bed reactor with an inner diameter of 10 mm and a length of 1 m, the reaction temperature was 120 ℃, the reaction pressure was 3 MPa, the mass space velocity of the raw materials was 7 h -1 (benzene to olefin molar ratio was 40).

[0031] The life of the catalyst was determined by the olefin breakthrough time in the product, and the life of the catalyst referred to the time (h) when the conversion rate of n-dodecene in the linear alkylbenzene product was less than 99% after chromatography.

[0032] The alkylation reaction-regeneration results are shown in Table 2. In Table 2, LAB, 2-LAB refer to the selectivity of linear alkylbenzene and 2-LAB in the product. The components in the linear alkylbenzene product were analyzed by an online chromatographic analyzer (GC-7890B of Agilent).

[0033] Comparative Example 1

[0034] This comparative example is used to illustrate the alkylation reaction-regeneration method of the catalyst under the condition of higher regeneration temperature.

[0035] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogen regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0036] Comparative Example 2

[0037] This comparative example is used to illustrate the alkylation reaction-regeneration method of the catalyst under the condition of higher regeneration pressure.

[0038] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogen regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0039] Comparative Example 3

[0040] This comparative example is used to illustrate the alkylation reaction-regeneration method of the catalyst under the condition of higher regeneration pressure.

[0041] The solid acid is prepared by uniformly mixing Y zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, wherein the unit cell constant of the Y zeolite is 2.446 nm, the ratio of mesopore volume to total pore volume is 0.13, and the obtained solid acid catalyst is marked as B1.

[0042] The specific physical and chemical properties and the hydrogen regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0043] Comparative Example 4

[0044] This comparative example is to illustrate the alkylation reaction-regeneration process of the catalyst under lower regeneration temperature condition.

[0045] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogenation regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0046] Comparative Example 5

[0047] This comparative example is to illustrate the alkylation reaction-regeneration process of the catalyst under lower regeneration pressure condition.

[0048] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogenation regeneration conditions are shown in Table 1, the alkylation reaction-regeneration is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0049] Comparative Example 6

[0050] This comparative example is to illustrate the alkylation reaction-regeneration process of the catalyst under lower hydrogen flow condition.

[0051] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogenation regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0052] Comparative Example 7

[0053] This comparative example is to illustrate the alkylation reaction-regeneration process of the catalyst under higher hydrogen temperature rising rate condition.

[0054] The specific physical and chemical properties and the hydrogenation regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0055] Comparative Example 8

[0056] This comparative example is to illustrate the alkylation reaction-regeneration process of the catalyst under shorter hydrogen constant temperature treatment time condition.

[0057] The solid acid is the same as in Example 1, the specific physical and chemical properties and the hydrogenation regeneration conditions are shown in Table 1, the alkylation reaction is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0058] Table 1

[0059]

[0060] Table 2

[0061]

[0062] From the result data of Table 2, it can be seen that the regeneration method of the present application, strictly controlling the regeneration conditions of the regeneration temperature, pressure, hydrogen flow rate, temperature rising rate and constant temperature time, can completely restore the activity of the solid acid catalyst, the catalyst life after six times of regeneration can still maintain the initial life of 42h, the LAB selectivity and 2-LAB selectivity are as high as 91.2% and 26.2% respectively; while any one of the above regeneration conditions does not meet the conditions of the present application, for example, the comparative example, the activity of the solid acid catalyst cannot be completely restored, the catalyst life is shortened after six times of regeneration, between 16-36h, and the LAB selectivity and 2-LAB selectivity are between 74.5%-90.5% and 19.5%-25.7% respectively.

[0063] Example 2

[0064] This example is used to illustrate the regeneration method of the alkylation reaction of the solid acid catalyst of the present application.

[0065] The solid acid is prepared by uniformly mixing Y zeolite (purchased from Sinopec Catalyst Branch) and zirconium oxide in a weight ratio of 4:1, wherein the unit cell constant of the Y zeolite is 2.448 nm, the ratio of mesopore volume to total pore volume is 0.15, and the obtained solid acid catalyst is marked as A2. The specific physicochemical properties and hydrogen regeneration conditions are shown in Table 1, the alkylation reaction-regeneration is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0066] Example 3

[0067] This example is used to illustrate the regeneration method of the alkylation reaction of the solid acid catalyst of the present application.

[0068] The solid acid is prepared by uniformly mixing Y zeolite (purchased from Sinopec Catalyst Branch) and aluminum oxide in a weight ratio of 4:1, wherein the unit cell constant of the Y zeolite is 2.457 nm, the ratio of mesopore volume to total pore volume is 0.29, and the obtained solid acid catalyst is marked as A3. The specific physicochemical properties and hydrogen regeneration conditions are shown in Table 1, the alkylation reaction-regeneration is the same as in Example 1, and the alkylation reaction-regeneration results are shown in Table 2.

[0069] Table 3

[0070]

[0071] Table 4

[0072]

Claims

1. A method for regenerating a solid acid catalyst used in the synthesis of long-chain alkyl aromatics, characterized in that, The deactivated solid acid catalyst was heated to 300-460°C in a hydrogen atmosphere at a heating rate of 1-15°C / min and treated at this temperature and under conditions of 1.5-3 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 h. The solid acid catalyst contained Y-type zeolite with a metal component supported on it for hydrogenolysis. The Y-type zeolite had a cell size of 2.448-2.457 nm and a mesopore volume to total pore volume ratio of 0.15-0.

29. The metal component for hydrogenolysis accounted for 0.15-5 wt% of the solid acid catalyst. The long-chain alkyl aromatic hydrocarbon was obtained by alkylation of an aromatic hydrocarbon and a long-chain olefin, wherein the long-chain olefin included C... 10 ~C 14 One or more of the long-chain olefins, wherein the aromatic hydrocarbon is one or more of monocyclic or polycyclic aromatic hydrocarbons.

2. The regeneration method according to claim 1, characterized in that, The solid acid catalyst also includes an inorganic oxide matrix.

3. The regeneration method according to claim 2, characterized in that, The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

4. The regeneration method according to claim 1, characterized in that, The Y-type zeolite is based on a solid acid catalyst and has a content of 40–95 wt%.

5. The regeneration method according to claim 1, characterized in that, The Y-type zeolite has a cell size of 2.452–2.455 nm.

6. The regeneration method according to claim 1, characterized in that, The Y-type zeolite has a mesopore volume to total pore volume ratio of 0.18 to 0.

26.

7. The regeneration method according to claim 1, characterized in that, The metal component responsible for hydrogenolysis accounts for 0.2–2 wt% of the solid acid catalyst.

8. The regeneration method according to claim 1, characterized in that, The metal component responsible for hydrogenolysis accounts for 0.4 to 1 wt% of the solid acid catalyst.

9. The regeneration method according to claim 1, characterized in that, The metal component with hydrogenolysis performance is selected from one or more metals of Groups VIB, VIIB and VIII.

10. The regeneration method according to claim 9, characterized in that, The group VIII metal is selected from one or more of Pt, Pd, and Ru.

11. The regeneration method according to claim 1, characterized in that, The aromatic hydrocarbon is benzene or toluene.

12. The regeneration method according to claim 1, characterized in that, The long-chain olefin is C 10 ~C 14 One or more of the long-chain olefins.

13. The regeneration method according to claim 1 or 12, characterized in that, The long-chain olefins are selected from decene, undecene, dodecene, tridecene, tetradecene and their isomers.

14. The regeneration method according to claim 1, characterized in that, The deactivated solid acid catalyst was heated to 350-420℃ in a hydrogen atmosphere at a heating rate of 1-7℃ / min and treated at this temperature and under the conditions of 2.0-2.5MPa and a hydrogen flow rate of 180-300mL / min / g for at least 5h.

15. A method for synthesizing long-chain alkyl aromatics, characterized in that, The process includes the alkylation reaction of long-chain olefins and aromatics and the regeneration process of a solid acid catalyst. The long-chain alkyl aromatics are obtained by the alkylation reaction of aromatics and long-chain olefins, wherein the long-chain olefins include C... 10 ~C 14 The alkylation reaction involves one or more long-chain olefins, wherein the aromatic hydrocarbon is one or more monocyclic or polycyclic aromatic hydrocarbons; during the alkylation reaction of the long-chain olefin and the aromatic hydrocarbon, the alkylation reaction conditions are a temperature of 90–180 °C, a pressure of 2.0–4.5 MPa, and a feed mass hourly space velocity of 1–30 h⁻¹. -1 The solid acid catalyst is a Y-type zeolite supported with a metal component having hydrogenolysis properties. The Y-type zeolite has a cell size of 2.448–2.457 nm and a mesopore volume to total pore volume ratio of 0.15–0.

29. The metal component having hydrogenolysis properties accounts for 0.15–5 wt% of the solid acid catalyst. The regeneration process of the solid acid catalyst involves heating the solid acid catalyst to 300–460 °C in a hydrogen atmosphere at a heating rate of 1–15 °C / min and treating it at this temperature and under conditions of 1.5–3 MPa and a hydrogen flow rate of 150–500 mL / min / g for at least 5 h.

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