A method for preparing an L-type low-temperature shift catalyst and its application

Abstract

This invention provides a method for preparing an L-type low-temperature shift catalyst and its application. In an alumina sol system, precursors of active materials Cu, Zn, and zirconium, along with auxiliary inorganic salts, are added. The mixture is thoroughly mixed, sheared, and dispersed using a twin-screw reactive extruder to form a slurry. A molding lubricant is added to the mixed material, which is then dried at 300℃-350℃. The material after intermediate phase decomposition is directly pre-pressed into tablets; these tablets are then crushed and shaped to obtain a finished catalyst that does not require calcination. This catalyst improves the dispersion of active copper microcrystals on the support, and the crystals do not easily grow under high temperatures, maintaining the catalyst's thermal stability during use. Its heat resistance temperature is more than 10℃ higher than that of ordinary shift catalysts. Due to the addition of auxiliary agents, the methanol content of the byproduct after the shift reaction is less than 300ppm. The catalyst's bulk density is less than 1.25 g / cm³. 3 Specific surface area greater than 100cm² 2 / g. Primarily used for deep conversion of low-CO content (2-7%), with a conversion rate exceeding 95% and an outlet CO content below 0.2%. After 4 hours of heat treatment at 400℃, the active CO conversion rate is greater than 80%, and the copper crystal size is less than 8nm, extending the catalyst's lifespan from 3 years to over 4 years.

Description

Technical Field

[0001] This invention relates to a method for preparing an L-type low-temperature shift catalyst and its application, particularly suitable for low-temperature shift in ammonia synthesis processes, achieving deep conversion of CO content from 2% to 7%, and can also be used for methanol synthesis in alcohol synthesis. The process is characterized by a short, stable, reliable flow, no calcination required, and low cost. The catalyst prepared by this special process has a low bulk density, small copper crystal size, large specific surface area, high conversion rate, and maintains high activity even after heat treatment, extending the catalyst's lifespan from 3 years to over 4 years. Background Technology

[0002] Currently, the main method for preparing low-temperature shift catalysts is co-precipitation. Copper and zinc nitrates react with a precipitant to form a binary slurry after co-precipitation, which is then loaded onto an aluminum substrate and subjected to washing, filtration, drying, granulation, calcination, and tableting processes. This process results in a long production cycle and high equipment investment costs. In addition, the prepared catalysts have problems such as high bulk density, large initial particle size of active copper microcrystals, small specific surface area, poor heat resistance, and short lifespan. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an L-type low-temperature shift catalyst and its application, which solves the problems of long preparation process, high cost, high bulk density, large catalyst loading, large original particle size of active copper microcrystals, easy fusion and growth under high load, and short service life of current low-temperature shift copper catalysts.

[0004] This invention discloses a method for preparing an L-type low-temperature shift catalyst and its application. The method mainly involves adding precursors of active materials Cu, Zn, and zirconium, along with auxiliary inorganic salts, to an alumina sol system at 80°C. The mixture is then thoroughly mixed, sheared, and dispersed using a twin-screw reactive extruder to form a slurry. A molding lubricant is added to the mixed material, which is then pumped into a flash dryer for heat exchange with hot air. The dried and decomposed material is pre-pressed, crushed, and reshaped to obtain a finished catalyst that does not require calcination.

[0005] The main technical solution of this invention is a method for preparing an L-type low-temperature shift catalyst, characterized by using a catalyst formulation containing copper, zinc, and zirconium. In an aluminum sol system, precursors of active substances Cu, Zn, and zirconium, along with auxiliary inorganic salts, are added at 70-80°C. The mixture is then thoroughly mixed, sheared, and dispersed using a twin-screw reactive extruder to form a slurry. After mixing, a molding lubricant is added to the material for drying. The material is then placed in a flash dryer for heat exchange with hot air. The dried and decomposed material is pre-pressed, crushed, and reshaped to obtain a finished catalyst that does not require calcination.

[0006] Furthermore, Al in aluminum sol 3+The concentration is not greater than 50 g / L, and the preferred concentrations are 5, 15, 25, and 35 g / L; the preferred inorganic aluminum salt for aluminum sol is Al(NO3)3·9H2O.

[0007] The aluminum sol is prepared by a powder dispersion method, an inorganic salt raw material method, an organic salt hydrolysis method, or an aluminum-hydrochloric acid method, with the inorganic salt raw material method being preferred.

[0008] The precursor of Cu is derived from one or more of the inorganic salts, complex salts, and complexed copper.

[0009] Preferably, the source of Cu is Cu(OH)2 solution, and the concentration is controlled at 20-40 g / L.

[0010] The Zn precursor is derived from one or more of the inorganic salts, complex salts, and zinc complexes of Zn.

[0011] Preferably, the Zn source is a Zn2(OH)2CO3 solution with a concentration controlled at 20-40 g / L.

[0012] The zirconium precursor is derived from Zr nitrate, preferably Zr(NO3)4·5H2O, with a concentration controlled at 5-25 g / L.

[0013] The inorganic salt of the auxiliary agent is a carbonate or nitrate, preferably KHCO3, and the concentration is controlled at 2-8 g / L.

[0014] In the preparation method of the present invention, the front end of the twin-screw reactive extruder is provided with multiple feed ports for inorganic aluminum salt, precipitant, and nitric acid; the middle end is provided with multiple feed ports for Cu precursor, Zn precursor, zirconium precursor, and auxiliary inorganic salt; the end is provided with an exhaust port; a weir plate of a certain height is provided in front of the middle end to enhance material mixing; the twin-screw reactive extruder adopts an electric heating module as a whole, with zoned and segmented heating, and a temperature adjustment range of 20-500℃; preferably, the twin-screw reactive extruder is provided with automatic weighing, automatic metering, and automatic continuous operation facilities.

[0015] The molding lubricant is any one of alcohol, ester and graphite, preferably graphite, and the amount added is no more than 10 wt%.

[0016] The material is instantly dried and calcined after exchanging heat with hot air at 300℃-350℃ in a flash dryer, and the output state is powder.

[0017] The material pressed out by the pre-compressed sheet has either a strip structure or a circular structure, preferably a strip structure, with dimensions of 2.0~5.0mm*2.0~5.0mm*0.5~2mm.

[0018] The L-type low-temperature shift catalyst prepared by the method of this invention is mainly used for low-temperature shift in ammonia synthesis processes, for deep conversion of CO content of 2-7%, or for methanol synthesis in combined alcohol production.

[0019] In this invention, the "L" in L-type low-temperature shift catalyst indicates low bulk density; for details, please refer to the enterprise standard Q / SH 1170083-2022 "B207-L-type carbon monoxide low-temperature shift catalyst".

[0020] The L-type low-temperature shift catalyst provided by this invention improves the dispersion of active copper microcrystals on the support and prevents crystal growth under high-temperature conditions, thus maintaining the thermal stability of the catalyst during use. Its heat resistance temperature is more than 10°C higher than that of ordinary shift catalysts. Due to the addition of additives, the methanol content of the byproduct after the shift reaction is less than 300 ppm. The catalyst's bulk density is less than 1.25 g / cm³. 3 Specific surface area greater than 100cm² 2 / g. Primarily used for deep conversion of low-CO content (2-7%), with a conversion rate exceeding 95% and an outlet CO content below 0.2%. After 4 hours of heat treatment at 400℃, the active CO conversion rate is greater than 80%, and the copper crystal particle size is less than 8nm, extending the catalyst's lifespan from 3 years to over 4 years. Implementation

[0021] The present invention will be described in detail below through embodiments. These embodiments are only for further explaining the content and effects of the present invention, and the effects of the method of the present invention are not limited thereto. Example

[0022] In the embodiment, aluminum sol is prepared at the front end of the twin-screw reactive extruder. Al(NO3)3·9H2O and precipitant NaOH are added to the parallel feed ports A and B at the front end, respectively. Feed port C is provided in the check section for adding acid to adjust the pH and control the pH of the aluminum sol between 6.8 and 7.2. Active substances Cu, Zn, zirconium precursors and auxiliary inorganic salts are added to the four sets of parallel feed ports D, E, F and G in the middle section, respectively.

[0023] In this embodiment, a twin-screw extrusion process is used to replace the traditional mechanical stirring, thereby achieving continuous production of the catalyst. The shearing, mixing, and dispersing effects of the twin screw and weir plate are utilized to enhance the mixing effect between materials.

[0024] In this embodiment, after the slurry is mixed with the molding lubricant, it enters a flash dryer through a metering pump. In the dryer, it exchanges heat with hot air at 300℃-350℃. During the drying process, the material after the intermediate phase decomposition can be directly pre-pressed into sheets. The pre-pressed sheets are strip-shaped with dimensions of 2.0~5.0mm in length, 2.0~5.0mm in width, and 0.5~2mm in thickness. The pre-pressed sheets are crushed, sieved through a 100-mesh sieve, and then formed into sheets to obtain a finished catalyst that does not require calcination. Example 1

[0025] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum sol with a concentration of 5 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 5 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite, a molding lubricant, was added. After flash evaporation, pre-pressing, crushing and molding, the finished catalyst CAT-1 was obtained. Example 2

[0026] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 15 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 5 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G in the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-2 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 3

[0027] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 5 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-3 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 4

[0028] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 35 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 5 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of lubricant graphite was added, and the catalyst product CAT-4 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 5

[0029] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 2 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-5 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 6

[0030] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G in the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-6 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 7

[0031] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 30 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of lubricant graphite was added, and the catalyst product CAT-7 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 8

[0032] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 20 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of lubricant graphite was added, and the catalyst product CAT-8 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 9

[0033] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 30 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G in the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-9 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 10

[0034] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 20 g / L Zn2(OH)2CO3, 15 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G in the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-10 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 11

[0035] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al... 3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 10 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G at the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-11 was obtained by flash evaporation, pre-pressing, crushing and molding. Example 12

[0036] Al(NO3)3·9H2O and a 1 mol / L NaOH precipitant solution were added to parallel feed ports A and B at the front end of a twin-screw reactive extruder, respectively. Thorough mixing was achieved using the shearing and mixing action of the twin screws and weir plates. Acid was added to the subsequent feed port C to adjust the pH of the aluminum sol to 6.8-7.2, and the temperature was controlled at 75-78℃ to obtain Al...3+ Aluminum glue with a concentration of 25 g / L was prepared by adding 40 g / L Cu(OH)2, 40 g / L Zn2(OH)2CO3, 5 g / L Zr(NO3)4·5H2O and 8 g / L KHCO3, respectively, to four parallel feed ports D, E, F and G in the middle of the extruder to form a slurry. Then, 0.5-2 wt% of graphite lubricant was added, and the catalyst product CAT-12 was obtained by flash evaporation, pre-pressing, crushing and molding.

[0037] Comparison sample

[0038] A commercially available B207 type low-temperature shift catalyst was used as a control sample and named CAT-Sample.

[0039] Sample testing

[0040] Catalyst samples: particle size 0.425~1.180 mm.

[0041] Activity testing before heat resistance:

[0042] The activity assay conditions were as follows: a double-tube (or single-tube) reactor with an inner diameter of 24 mm was used; the catalyst loading was 30 mL; the activity assay pressure was 2.0 MPa ± 0.02 MPa; and the activity assay space velocity was 4000 h⁻¹. -1 ±50h -1 Activity assay temperature: 200℃±1℃; Water vapor to raw material gas volume ratio: 0.33±0.02; Raw material gas composition (by volume fraction): carbon monoxide (2.5%~4.0%), carbon dioxide (14.0%~20.0%), and the remainder is composed of hydrogen and nitrogen (3:1).

[0043] Activity testing after heat resistance:

[0044] The reactor pressure was increased to 2.0 MPa and the space velocity was increased to 4000 h⁻¹ within 0.5 h. -1 The reactor temperature is raised to 400℃ within 1 hour and maintained for 4 hours, then rapidly cooled to 200℃. Simultaneously, the insulated pipe vaporizer is heated, with the insulated pipe temperature controlled at approximately 150℃ and the vaporizer temperature at approximately 250℃. The horizontal flow pump is started, and after the reactor pressure, temperature, feed gas space velocity, water-to-vapor ratio, and vaporizer temperature stabilize for 2-3 hours, the volume fraction of carbon monoxide in the feed gas and shift gas is analyzed using a gas chromatograph (or other carbon monoxide analyzer), and the carbon monoxide conversion rate is calculated. Analysis is then performed every 1-1.5 hours. The experiment can be terminated when the absolute difference between three consecutive carbon monoxide conversion rate measurements is less than or equal to 2%.

[0045] The activity test results are shown in Table 1. Among them, catalyst samples CAT-1, CAT-2, CAT-3, CAT-4, CAT-5, CAT-6, CAT-7, CAT-8, CAT-9, CAT-10, CAT-11, and CAT-12 were prepared in this invention.

[0046] Table 1. Activity test results

[0047] .

[0048] The activity of the above catalysts was evaluated after heat resistance, and the results are shown in Table 2.

[0049] Table 2. Results of bulk density measurement

[0050] .

[0051] As can be seen from Tables 1 and 2, the specific gravity of the low-temperature shift catalyst prepared using this invention is less than 1.25 g / cm³. 3 The specific surface area is higher than that of the comparative catalyst, the copper crystal particle size is less than 8nm, the active material is more uniformly dispersed, the methanol content of the by-product is less than 300ppm, the selectivity is higher, the CO conversion rate is higher than 95%, and the activity is still greater than 80% after 4h of heat resistance at 400℃. This shows that the present invention has obvious advantages over the existing catalyst production methods and has broad market prospects.

Claims

1. A method for preparing an L-type low-temperature shift catalyst, characterized in that... A catalyst formulation containing copper, zinc, and zirconium is used. In an aluminum sol system, precursors of active substances Cu, Zn, and zirconium, along with auxiliary inorganic salts, are added at 70-80℃. The mixture is thoroughly mixed, sheared, and dispersed using a twin-screw reactive extruder to form a slurry. After mixing, a molding lubricant is added, and the mixture is dried. It then enters a flash dryer for hot air heat exchange. The dried and decomposed material is pre-pressed, crushed, and reshaped to obtain a finished catalyst that does not require calcination. The aluminum sol contains Al... 3+ The concentration is not greater than 50 g / L; the Cu precursor is Cu(OH)2 solution with a concentration controlled at 20-40 g / L; the Zn precursor is Zn2(OH)2CO3 solution with a concentration controlled at 20-40 g / L; the zirconium precursor is Zr(NO3)4·5H2O with a concentration controlled at 5-25 g / L.

2. The preparation method according to claim 1, characterized in that... Al in aluminum sol 3+ The concentrations are 5, 15, 25, and 35 g / L; the inorganic aluminum salt of the aluminum sol is Al(NO3)3·9H2O.

3. The preparation method according to claim 1 or 2, characterized in that... Aluminum sol can be prepared by powder dispersion, inorganic salt raw material method, organic salt hydrolysis method or aluminum-hydrochloric acid method.

4. The preparation method according to claim 3, characterized in that... Aluminum sol is prepared by the inorganic salt raw material method.

5. The preparation method according to claim 1, characterized in that... The inorganic salts used in the additives are carbonates or nitrates.

6. The preparation method according to claim 1 or 5, characterized in that... The inorganic salt of the auxiliary agent is KHCO3 3， The concentration should be controlled between 2-8 g / L.

7. The preparation method according to claim 1, characterized in that... The twin-screw reactive extruder has multiple feed ports at the front end for inorganic aluminum salts, precipitants, and nitric acid; multiple feed ports in the middle for Cu precursors, Zn precursors, zirconium precursors, and inorganic salt additives; and an exhaust port at the end. A weir plate of a certain height is installed in front of the middle end to enhance material mixing. The twin-screw reactive extruder adopts an electric heating module throughout, with zoned and segmented heating and a temperature adjustment range of 20-500℃.

8. The preparation method according to claim 7, characterized in that... The twin-screw reactive extruder is equipped with automatic weighing, automatic metering, and automatic continuous operation facilities.

9. The preparation method according to claim 1, characterized in that... The molding lubricant is any one of alcohol, ester, and graphite.

10. The preparation method according to claim 1 or 9, characterized in that... The molding lubricant is graphite, and the amount added is no more than 10 wt%.

11. The preparation method according to claim 1, characterized in that... After the material is heated by a flash dryer with hot air at 300℃-350℃, it is instantly dried and calcined, and the output state is powder.

12. The preparation method according to claim 1, characterized in that... The material extruded from the pre-compressed tablets can be either strip-shaped or circular.

13. The preparation method according to claim 1 or 12, characterized in that... The material extruded from the pre-compressed sheet is a strip structure with dimensions of 2.0~5.0mm in length, 2.0~5.0mm in width, and 0.5~2mm in thickness.

14. An application of an L-type low-temperature shift catalyst prepared by the method according to any one of claims 1-13, characterized in that: It can be used for low-temperature conversion in ammonia synthesis processes, for deep conversion with CO content of 2-7%, or for methanol synthesis in combined alcohol production.