CN111085189B

CN111085189B - Sulfur-tolerant shift methanation bifunctional catalyst and preparation method thereof

Info

Publication number: CN111085189B
Application number: CN201811243250.2A
Authority: CN
Inventors: 白志敏; 赵庆鲁; 余汉涛; 李文柱; 田兆明; 齐焕东; 王昊; 姜建波; 薛红霞; 陈依屏
Original assignee: China Petroleum and Chemical Corp; Qilu Petrochemical Co of Sinopec
Current assignee: China Petroleum and Chemical Corp; Qilu Petrochemical Co of Sinopec
Priority date: 2018-10-24
Filing date: 2018-10-24
Publication date: 2022-10-14
Anticipated expiration: 2038-10-24
Also published as: CN111085189A

Abstract

The invention belongs to the field of sulfur tolerant shift and methanation reactions, and particularly relates to a sulfur tolerant shift methanation bifunctional catalyst, and a preparation method and application thereof. According to the preparation method of the catalyst provided by the invention, the oxides of Al, si and Ba in the carrier are mainly from the waste catalytic cracking catalyst, the waste catalytic cracking catalyst can partially replace the commonly used alumina or aluminum-containing compound in the bifunctional catalyst after being treated, and meanwhile, the titanium-containing compound is added by adopting a proper method, so that the catalyst has stronger strength and strength stability. The catalyst provided by the invention adopts Mo as an active component, and the active component is well dispersed on the surface of the carrier and is not easy to run off by selecting a proper active component adding mode, so that the structure and activity stability of the catalyst are good. On the catalyst of the invention, two reactions of methanation and CO transformation can be carried out simultaneously, the selectivity of the methanation reaction is not lower than 90%, the catalyst can be activated when the temperature is lower than 300 ℃, and the service life is longer.

Description

Sulfur-tolerant shift methanation bifunctional catalyst and preparation method thereof

Technical Field

The invention belongs to the field of sulfur tolerant shift and methanation reactions, and particularly relates to a sulfur tolerant shift methanation bifunctional catalyst, and a preparation method and application thereof.

Background

The utilization of the coal gasification hydrogen production device by-product small amount of low heat value fuel gas is generally set with a conversion line and a non-conversion line to respectively satisfy the hydrogen and fuel gas (CO + H) of the refinery ₂ ) But the investment of the device is large, the heat value of the fuel gas is low, and the requirements of hydrogen and the fuel gas cannot be flexibly switched. If through embedding methanation process in the transform workshop section, cancel non-transform line to shift and methanation reaction simultaneously, after purifier desorption acid gas, separate out pure hydrogen by PSA, the by-product desorption gas sends into the pipe network as high calorific value fuel gas, then can satisfy the demand to hydrogen and fuel gas simultaneously, improves the reliability, flexibility and the economic nature of device by a wide margin. The prior art mainly focuses on sulfur-tolerant methanation reaction, and the research on the methanation reaction of the synthesis gas mainly comprises two process routes: one is Ni/Al which is extremely sensitive to hydrogen sulfide ₂ O ₃ A system-catalyzed non-sulfur tolerant methanation process; another process route is the sulfur tolerant methanation process catalyzed by molybdenum based catalysts. The sulfur-tolerant methanation has certain cost advantage because the fine desulfurization treatment of the raw material gas is not needed, and the process can be simplified. However, relatively little research has been done on both the sulfur tolerant shift and methanation reactions.

The catalytic cracking (FCC) catalyst in an oil refinery is the catalyst with the largest application amount in the oil refinery process, the annual amount of the catalyst used in China exceeds 100kt, and the amount of the waste agent generated after the catalyst is used is gradually increased along with the increase of the scale of the FCC, so that the catalyst is not only an economic problem, but also is more mainly an environmental protection problem. This type of waste agent has low activity, and also contains a certain amount of heavy metals or nonvolatile carbon-like substances, mainly Ni, V, fe, cu, etc., and how to treat it has been one of the topics to which the skilled person is concerned.

The waste catalytic cracking catalyst mainly comprises Al ₂ O ₃ 、SiO ₂ Clay and BaCO ₃ Prepared by mixing Al as a carrier ₂ O ₃ And SiO ₂ The content can reach about 95 percent (w), because the oxides can be used as the basic raw materials of the catalyst, in addition, most heavy metals such as Ni, V, fe and Cu contained in the waste agent have activity to certain reactions or can increase the reaction activity, and meanwhile, the catalyst prepared by taking the waste catalytic cracking catalyst as the raw material can not only reduce the preparation cost, but also find an effective utilization way for the waste catalytic cracking catalyst with wide sources and low cost, and relieve the huge pressure of the treatment of the waste catalytic cracking catalyst to the ecological environment. At present, the method which has a more successful result is to recycle the waste agent part and reduce the amount of discarded treatment, and the method mainly comprises the steps of recycling by a magnetic separation technology, using the waste agent as a cement substitute material, using the waste agent as a flame retardant and a microorganism growth inhibitor, recrystallizing the waste agent into a catalyst and the like, but related research and reports applied to the field of molybdenum-series sulfur-tolerant shift methanation dual-function catalysts are not found.

Chinese patent application CN106140296A discloses a method for recycling catalytic cracking waste catalyst, in which catalytic cracking waste catalyst is used as main aluminum source and part of silicon source, and fresh catalytic cracking catalyst is prepared by in-situ crystallization method. However, the document does not mention how to further adjust the composition of the catalytic cracking spent catalyst based on the catalytic cracking spent catalyst so as to make the catalyst suitable as a carrier of the sulfur-tolerant shift methanation dual-function catalyst.

Chinese patent application CN108097264A discloses a method for preparing a catalytic cracking combustion improver, selecting waste agent (i.e. FCC waste catalyst) residue with platinum content of 0.06-0.1% as raw material, pulverizing to particle size less than 30 μm with a pulverizer, mixing and stirring with inorganic acid solution with pH value of 3-4, stirring at normal temperature for 10-12 hours, adding organic acid, stirring for 1-2 hours, standing for 6-8 hours, drying at 110 ℃ for 2-5 hours, and calcining at 350-750 ℃ for 1-3 hours to obtain the catalyst, wherein the inorganic acid solution: organic acid solution: the weight ratio of the waste agent residue with the platinum content of 0.06-0.1% is (5-8): 2-4): 1; then the calcined catalyst is used as a carrier. However, the spent FCC catalyst in this document must be subjected to an acid treatment, i.e. calcination, before it can be used as a support for a combustion improver, and there is no mention of how to further adjust the composition of the spent FCC catalyst on the basis of the spent FCC catalyst to make it suitable as a support for a sulfur-tolerant shift methanation dual-function catalyst.

Disclosure of Invention

In order to solve the problems, the application tries to develop a sulfur-resistant conversion methanation dual-function catalyst by taking catalytic cracking (FCC) catalyst waste agent as a carrier part material, adding a proper amount of alumina and titanium oxide materials and adding a molybdenum salt active component and a preparation method thereof ₂ -SiO ₂ -Al ₂ O ₃ The catalyst is the main part of the carrier, is prepared by adopting a kneading process, and has simple and feasible process and good stability of catalyst structure and activity. On the catalyst, methanation and CO conversion reactions can be carried out simultaneously, the methanation reaction has high selectivity, and the catalyst can be activated when the temperature is lower than 300 ℃. The catalyst provides possibility for a coal gasification hydrogen production device to produce a byproduct of low-heat-value fuel, creates a new route for co-production of fuel gas from coal to hydrogen, and greatly improves the reliability, flexibility and economy of the coal gasification hydrogen production device.

Therefore, the technical problem to be solved by the invention is as follows: a sulfur-tolerant shift methanation dual-function catalyst and a preparation method thereof are provided, two reactions of methanation and CO shift can be simultaneously carried out on the catalyst, the selectivity of the methanation reaction is high, the catalyst can be activated when the temperature is lower than 300 ℃, and the service life is long. And how to use the waste catalytic cracking catalyst, such as FCC spent catalyst, as the component of the catalyst carrier, partially replace the current catalyst carrier material, thereby achieving the purpose of reducing the production cost of the catalyst, finding a more effective treatment and utilization approach for the waste catalytic cracking catalyst with wide sources and low cost, relieving the huge pressure of the waste catalytic cracking catalyst on the ecological environment, and leading the production process of the catalyst to have good economic benefit and environmental protection benefit.

In order to solve the technical problems, the invention provides a sulfur-tolerant shift methanation dual-function catalyst and a preparation method thereof, wherein a carrier of the sulfur-tolerant shift methanation dual-function catalyst is a composite oxide formed by oxides of Al, si, ti and Ba, mo is used as an active component, and the content of Mo is 13.0-30.0 wt%, preferably 16.5-25.0 wt%, calculated by molybdenum oxide.

The preparation process of the catalyst of the invention is as follows:

raw material treatment:

a certain amount of waste catalytic cracking catalyst is firstly roasted at high temperature, crushed and sieved;

silica (SiO) in spent catalytic cracking catalyst ₂ ) And alumina (Al) ₂ O ₃ ) The total content should not be less than 85wt.%, based on the weight of the spent catalytic cracking catalyst; the dosage of the waste catalytic cracking catalyst accounts for 20-50 wt% of the weight of the catalyst; the crushed waste catalytic cracking catalyst is sieved by a 200-mesh sieve.

The roasting temperature for treating the waste catalytic cracking catalyst is 550-800 ℃, preferably 650 ℃, and the roasting time is 2-10 hours, preferably 4-6 hours.

The particle size of the treated waste catalytic cracking catalyst is 200 meshes, preferably 220 meshes.

Preparing an active component solution:

dissolving a certain amount of soluble molybdenum salt by using deionized water to obtain a solution A; preferably, the molybdenum salt is dissolved in water by heating, and a proper amount of ethylenediamine is added to obtain a stable molybdenum salt aqueous solution; ethylenediamine is preferably added dropwise in an amount of 1-3 (ml ethylenediamine): 10-40 (g molybdenum salt); the molybdenum salt is preferably ammonium heptamolybdate.

The catalyst forming and active component loading process comprises the following steps:

uniformly mixing the weighed waste catalytic cracking catalyst with a certain amount of powdery solid compound containing aluminum and powdery solid compound containing titanium, a pore-enlarging agent and a binder, adding the solution A, uniformly kneading, and preparing a catalyst finished product after molding, drying and roasting.

The aluminum-containing powdery solid compound is selected from pseudo-boehmite, alumina gel, aluminum nitrate and aluminum acetate, and preferably pseudo-boehmite; the content is 5-15 wt.% (m/m) calculated by alumina.

The powdery solid compound containing titanium is selected from metatitanic acid and titanium oxide, and preferably metatitanic acid in terms of titanium oxide; the content is 15-40 wt.% (m/m).

The pore-expanding agent is selected from sesbania powder, citric acid, starch and sucrose, and is preferably sesbania powder; the content thereof is 2 to 5wt.% (m/m), preferably 3 to 4wt.% (m/m).

The binder is selected from acetic acid, citric acid, oxalic acid and nitric acid, preferably nitric acid; the content thereof is 1 to 6wt.% (m/m), preferably 2 to 4wt.% (m/m).

The calcination temperature for the catalyst molding is 500 to 650 ℃, preferably 560 ℃.

The pore volume of the catalyst is preferably greater than 0.2cm ³ In g, more preferably greater than 0.3cm ³ (iv) g. The specific surface area is preferably more than 80m ² A/g, more preferably more than 100m ² /g。

The active component in the catalyst is molybdenum, wherein the content of molybdenum is 13.0-30.0 wt.% (m/m), preferably 16.5-25.0 wt.% (m/m) calculated by molybdenum oxide.

The catalyst has a composition of 20% (v/v) CO in the inlet gas, CO ₂ 25% (v/v), 0.2% sulfur, and the balance H ₂ At the time of the reaction, the inlet pressure is 3.5MPa, and the dry gas space velocity is 2000h ^-1 And under the condition of water-gas ratio of 0.1, the CO outlet of the methanation outlet of the sulfur-tolerant part is less than 12 percent, and the CH is ₄ The content is more than 4.0 percent. The inlet gas may be derived from a process for producing syngas from heavy feedstocks such as residuum, heavy oil, petroleum coke, coal, and the like.

The sulfur-tolerant shift methanation bifunctional catalyst has the following advantages:

1. the catalyst of the invention has higher strength, good stability of structure and activity, low loss rate of active components and longer service life. The Al, si and Ba oxides in the carrier are mainly from the waste catalytic cracking catalyst, the waste catalytic cracking catalyst can partially replace the common alumina or aluminum-containing compound in the bifunctional catalyst after being treated, and meanwhile, a titanium-containing compound is added by adopting a proper method, so that the catalyst has stronger strength and strength stability. The catalyst provided by the invention adopts Mo as an active component, and the active component is well dispersed on the surface of the carrier and is not easy to run off by selecting a proper active component adding mode, so that the structure and activity stability of the catalyst are good.

2. On the catalyst of the invention, two reactions of methanation and CO transformation can be carried out simultaneously, the selectivity of the methanation reaction is not lower than 90%, the catalyst can be activated when the temperature is lower than 300 ℃, and the service life is longer.

3. The preparation method of the catalyst is simple, and meanwhile, the catalyst raw material adopts the waste catalytic cracking catalyst with low cost, so that the preparation cost of the catalyst is greatly reduced, an effective way is found for the comprehensive utilization of the waste catalytic cracking catalyst, and the catalyst has good economic benefit and environmental protection benefit.

Drawings

In order that the manner in which the disclosure of the present invention is attained and can be more readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, wherein,

the device used by the invention is used for simulating industrial conditions, measuring the concentration change conditions of the 'original particle size' catalyst under different conditions, investigating the performances of the catalyst such as conversion activity, stability and the like, and comprehensively evaluating various performances of the catalyst. The process comprises the steps of adding a certain amount of water according to the requirements of different water-gas ratios, gasifying the water at high temperature, feeding the water and the feed gas into a reaction tube together for water gas shift and methanation reaction, and analyzing tail gas after the reaction by using a chromatographic method, wherein FIG. 1 is a schematic flow diagram of a pressurization evaluation device.

The reference numbers in the figures denote: 1. a raw material purifier; 2. a pressure reducer; 3. a mixer; 4. a pressure gauge; 5. a shutdown valve; 6. heating furnace; 7. a reaction tube; 8. a thermocouple tube in the tube; 9. a condenser; 10. a separator; 11. a liquid discharge device; 12. a wet flow meter; 13. a vaporizer; 14. a water tank; 15. a water metering pump.

Detailed Description

Example 1

The waste catalytic cracking catalyst is roasted for 5 hours at the temperature of 650 ℃, and then crushed and sieved by a 220-mesh sieve.

Dissolving 24.5g of ammonium heptamolybdate with 40.0ml of deionized water, and adding 1ml of ethylenediamine to obtain a stable molybdenum salt aqueous solution A; 3.0g of citric acid and 1.0g of oxalic acid in deionized water were dissolved to give solution B.

Weighing 45.0g of the treated waste catalytic cracking catalyst, 7.2g of pseudo-boehmite, 40.0g of metatitanic acid, 3.0g of sesbania powder and 1g of starch, uniformly mixing, adding the solution A, uniformly kneading, adding the solution B, uniformly kneading to form a phi 3 strip, naturally drying, roasting at 560 ℃ for 3 hours, and naturally cooling to room temperature. Thus obtaining the finished product catalyst C-1. The strength and activity results are shown in Table 1.

Example 2

The waste catalytic cracking catalyst is roasted for 2 hours at the temperature of 800 ℃, and then is crushed and sieved by a 200-mesh sieve.

30.7g of ammonium heptamolybdate was dissolved in 45.0ml of deionized water, and 1ml of ethylenediamine was added to obtain a stable aqueous solution a of molybdenum salt; weighing 30.0g of the treated waste catalytic cracking catalyst, 20.0g of alumina gel, 35.0g of titanium oxide, 2.0g of starch and 2.0g of cane sugar, uniformly mixing, adding the solution A, kneading, forming into phi 3 strips, naturally drying, roasting at 530 ℃ for 4 hours, and naturally cooling to room temperature. Thus obtaining the finished product catalyst C-2. The strength and activity results are shown in Table 1.

Example 3

The waste catalytic cracking catalyst is roasted for 10 hours at the temperature of 550 ℃, and then crushed and sieved by a 230-mesh sieve.

Dissolving 16.0g of ammonium heptamolybdate with 40.0ml of deionized water, and adding 1ml of ethylenediamine to obtain a stable molybdenum salt aqueous solution A; weighing 50.0g of the treated waste catalytic cracking catalyst, 204.0g of aluminum nitrate nonahydrate, 22.0g of titanium oxide, 4.0g of sesbania powder and 2g of starch, uniformly mixing, adding the solution A, uniformly kneading to form a phi 3 strip, naturally drying, roasting at 600 ℃ for 2 hours, and naturally cooling to room temperature. Thus obtaining the finished product catalyst C-3. The strength and activity results are shown in Table 1.

Example 4

The waste catalytic cracking catalyst is roasted for 3 hours at the temperature of 700 ℃, and then is crushed and sieved by a 250-mesh sieve.

Dissolving 36.8g of ammonium heptamolybdate with 60.0ml of deionized water, and adding 1ml of ethylenediamine to obtain a stable molybdenum salt aqueous solution A; weighing 20.0g of the treated waste catalytic cracking catalyst, 75.0g of aluminum acetate, 53.0g of metatitanic acid, 2g of oxalic acid, 2.0g of sucrose and 3.0g of sesbania powder, uniformly mixing, adding the solution A, uniformly kneading to form a phi 3 strip, naturally airing, roasting at 650 ℃ for 2 hours, and naturally cooling to room temperature. Thus obtaining the finished product catalyst C-4. The strength and activity results are shown in Table 1.

Example 5

The waste catalytic cracking catalyst is roasted for 8 hours at the temperature of 550 ℃, and then crushed and sieved by a 220-mesh sieve.

Firstly, 27g of ammonium heptamolybdate is dissolved by 45.0ml of deionized water, and 1ml of ethylenediamine is added to obtain a stable molybdenum salt aqueous solution A;

weighing 40.0g of the treated waste catalytic cracking catalyst, 13.6g of aluminum nitrate, 30.0g of titanium oxide, 5.0g of sesbania powder and 3g of sucrose, uniformly mixing, adding the solution A, adding 5.0ml of dilute nitric acid, uniformly kneading to form a phi 3 strip, naturally airing, roasting at 500 ℃ for 5 hours, and naturally cooling to room temperature. Thus obtaining the finished product catalyst C-5. The strength and activity results are shown in Table 1.

Example 6

The waste catalytic cracking catalyst is roasted for 6 hours at the temperature of 600 ℃, and then crushed and sieved by a 240-mesh sieve.

Firstly, 36.8g of ammonium heptamolybdate is dissolved by 60.0ml of deionized water, and 1ml of ethylenediamine is added to obtain a stable molybdenum salt aqueous solution A; weighing 42.0g of the treated waste catalytic cracking catalyst, 18.6g of pseudo-boehmite, 20.0g of metatitanic acid, 4.0g of sesbania powder and 2g of citric acid, uniformly mixing, adding the solution A, uniformly kneading, adding 3.0ml of acetic acid, kneading to form a phi 3 strip, naturally drying, roasting at 550 ℃ for 3 hours, and naturally cooling to room temperature. Thus obtaining the finished product of the catalyst C-6. The strength and activity results are shown in Table 1.

Comparative example 1

Silicon dioxide (SiO) ₂ ) And alumina (Al) ₂ O ₃ ) The spent catalytic cracking catalyst with a total content of 80% was prepared according to the protocol of example 1 to obtain the finished product catalyst D-1. The strength and activity results are shown in Table 2.

Comparative example 2

The waste catalytic cracking catalyst is roasted for 10 hours at the temperature of 500 ℃, and then is crushed and sieved by a 180-mesh sieve.

Firstly, dissolving 18.4g of ammonium heptamolybdate by 50.0ml of deionized water, and adding 1ml of ethylenediamine to obtain a stable molybdenum salt aqueous solution A; weighing 60.0g of the treated waste catalytic cracking catalyst, 7.1g of pseudo-boehmite, 26.7g of metatitanic acid, 2.0g of sesbania powder and 2.0g of citric acid, uniformly mixing, adding the solution A, uniformly kneading, adding 3.0ml of acetic acid and 3.0g of citric acid, kneading to form a phi 3 strip, naturally airing, roasting at 650 ℃ for 3 hours, and naturally cooling to room temperature. Thus obtaining the finished product of the catalyst D-2. The strength and activity results are shown in Table 2.

Comparative example 3

The waste catalytic cracking catalyst is roasted for 8 hours at the temperature of 700 ℃, and then is crushed and sieved by a 220-mesh sieve.

Firstly, dissolving 12.3g of ammonium molybdate by using 40.0ml of deionized water, and adding 1ml of ethylenediamine to obtain a stable molybdenum salt aqueous solution A; weighing 70.0g of the treated waste catalytic cracking catalyst, 68.0g of aluminum nitrate nonahydrate, 15.0g of titanium oxide and 4.0g of sesbania powder, uniformly mixing, adding the solution A, kneading uniformly to form a phi 3 strip, naturally drying, roasting at 600 ℃ for 3 hours, and naturally cooling to room temperature. Thus obtaining the finished product of the catalyst D-3. The strength and activity results are shown in Table 2.

Comparative example 4

Firstly, 36.8g of ammonium heptamolybdate is dissolved by 60.0ml of deionized water, and 1ml of ethylenediamine is added to obtain a stable molybdenum salt aqueous solution A; weighing 52.0g of the treated waste catalytic cracking catalyst, 24.3g of pseudo-boehmite, 4.0g of sesbania powder and 2g of citric acid, uniformly mixing, adding the solution A, uniformly kneading, adding 3.0ml of acetic acid, kneading into a phi 3 strip shape, naturally drying, roasting at 550 ℃ for 3 hours, and naturally cooling to room temperature. Thus obtaining the finished product of the catalyst D-4. The strength and activity results are shown in Table 2.

The sulfur-tolerant shift activity and methanation selectivity of the catalysts of the examples of the present invention and the comparative examples were measured by using a pressure evaluation apparatus, and the results are shown in tables 1 and 2.

Wherein the raw material gas comprises the following components: content of CO: 20.0 percent; CO 2 ₂ The contents are as follows: 25.0 percent;

H ₂ and (2) S content: more than 0.2 percent; and the balance: h ₂ ；

Catalyst loading: 60mL;

vulcanization conditions are as follows:

temperature: 250 ℃; pressure: 2.0MPa; dry gas space velocity: 2000h ^-1 ；H ₂ And (2) S content: 0.3 percent;

time: 20h;

initial evaluation conditions for catalyst pressurization:

inlet temperature: 300 ℃; pressure: 3.5MPa; water/gas: 0.1;

dry gas space velocity: 2000h ^-1 ；H ₂ And (2) S content: 0.2 percent; time: and (4) 40h.

TABLE 1 strength and pressure activity of catalysts of the present application

TABLE 2 strength and pressure activity of the comparative example catalysts

As can be seen from the evaluation results of tables 1 and 2, the catalyst of the present application has a significantly better combination of sulfur shift resistance activity and methanation selectivity than the comparative example.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications derived therefrom are intended to be within the scope of the invention.

Claims

1. The application of the sulfur-tolerant shift methanation dual-function catalyst in catalyzing two reactions of methanation and sulfur-tolerant shift at the same time is characterized in that the preparation method of the sulfur-tolerant shift methanation dual-function catalyst comprises the following steps:

(1) Raw material treatment:

silicon dioxide (SiO) in the spent catalytic cracking catalyst ₂ ) And alumina (Al) ₂ O ₃ ) The total content is not lower than 85wt.%, and the dosage of the waste catalytic cracking catalyst accounts for 20-50 wt.% of the weight of the catalyst; sieving the crushed waste catalytic cracking catalyst with a 200-mesh sieve; the roasting temperature is 550-800 ℃, and the roasting time is 2-10h;

(2) Preparing an active component solution:

dissolving a certain amount of soluble molybdenum salt by using deionized water, and adding a proper amount of ethylenediamine to obtain a stable molybdenum salt aqueous solution A;

(3) The catalyst forming and active component loading process comprises the following steps:

uniformly mixing the weighed waste catalytic cracking catalyst powder with a certain amount of aluminum-containing powdery solid compound, titanium-containing powdery solid compound, pore-enlarging agent and binder, adding the solution A, kneading uniformly, and forming, drying and roasting to obtain a catalyst finished product.

2. The use according to claim 1, wherein in step (1), the calcination temperature of the spent catalytic cracking catalyst treatment is 650 ℃ and the calcination time is 4-6h.

3. The use of claim 1, wherein in step (1), the crushed spent catalytic cracking catalyst is passed through a 220 mesh screen.

4. The use according to claim 1, wherein in step (2), the molybdenum salt is dissolved by heating in water to obtain an aqueous solution of molybdenum salt, the molybdenum salt being ammonium heptamolybdate.

5. Use according to claim 1, wherein in step (3), the powdered solid compound containing aluminium is selected from the group consisting of pseudoboehmite, alumina gel, aluminium nitrate, aluminium acetate; the content is 5-15 wt.% (m/m) calculated by alumina.

6. Use according to claim 1, characterized in that in step (3) the titanium-containing powdery solid compound is selected from metatitanic acid, titanium oxide in an amount of 15-40 wt.% (m/m) based on titanium oxide.

7. The use of claim 1, wherein in step (3), the pore-enlarging agent is selected from sesbania powder, citric acid, starch, sucrose; the content is 2-5 wt.% (m/m); the binder is selected from acetic acid, citric acid, oxalic acid and nitric acid; its content is 1-6 wt.% (m/m).

8. The use according to any one of claims 1 to 7, wherein the sulfur-tolerant shift methanation dual-function catalyst prepared by the preparation method contains an active component of molybdenum, wherein the content of molybdenum is 13.0-30.0 wt.% calculated by molybdenum oxide.

9. Use according to claim 8, characterized in that the support is a composite oxide consisting of oxides of Al, si, ti and Ba.