WO2000067898A1

WO2000067898A1 - Molecular sieve desulfurizers and methods of making them

Info

Publication number: WO2000067898A1
Application number: PCT/CN2000/000109
Authority: WO
Inventors: Jie Zhang; Ke Lin; Zhenyi Liu
Original assignee: Jie Zhang; Ke Lin; Zhenyi Liu
Priority date: 1999-05-11
Filing date: 2000-05-11
Publication date: 2000-11-16
Also published as: AU4534000A; AU5965599A; WO2000067897A1

Abstract

The present invention relates to a molecular sieve desulfurizer for removing organic sulfur compounds contained in liquid petroleum gas or light oil and methods for preparing the same. The main component of the desulfurizer is a X- or Y-molecular sieve exchanged with lanthanum, cerium or mixed light rare earth elements in its high valence state, the percentage of cations exchanged by the high valence metal cation are 70 %-95 %. Particularly, the desulfurizer can be used for directly removing neutral organic sulfur compounds contained in liquid petroleum gas or light oil by physical adsorption process, and has large adsorbing capacity, high percentage of removal, and the features of long regeneration period, easy-to-regenerate, long life period, and repeatable reuse.

Description

Molecular sieve desulfurizer and preparation method thereof

The invention relates to a molecular sieve type desulfurizing agent for removing organic sulfur compounds in liquefied petroleum gas or light oil products, and a preparation method thereof. Background technique

With the development of modern petrochemical technology, many high-efficiency catalysts are increasingly demanding on the sulfur content in the raw materials. On the other hand, environmental protection standards are becoming stricter and stricter requirements are imposed on the total sulfur content in petrochemical products. Sulfur in petrochemical products can be divided into organic sulfur and inorganic sulfur. Inorganic sulfur is mainly hydrogen sulfide, which can be easily removed using different desulfurizing agents and corresponding desulfurization processes. Organic stone fillings include thiol polar organic phosphants and non-polar organic sulfides (or neutral organic sulfides) such as thioether, thiophenol, thiocarbon, carbon disulfide, and thiophene; currently used to remove organic sulfur The methods include hydrodesulfurization method and catalytic oxidation method. The hydrodesulfurization method is to remove the above-mentioned organic ^ L in a hydrocarbon oil (including liquefied petroleum gas, naphtha, catalytic gasoline, aviation kerosene, kerosene, diesel oil) by converting it into an inorganic sulfide, which is relatively expensive. The catalytic oxidation method converts mercaptans into odorless thioethers, disulfides, etc., and extracts them with solvents. However, the accuracy of desulfurization cannot meet the requirements of low sulfur content in raw materials. The US patent US 4204947 introduces a method for fine mercaptan removal, which not only uses high temperature and harsh regeneration conditions, but also can only remove mercaptans, and is incapable of other forms of organic sulfur. Chinese patent CN 8510355.5A describes an iron-manganese-zinc-based desulfurizer. Although it has the advantage of a wide range of organic sulfur removal, the desulfurization activity temperature is greater than 350 ° C. Such a high desulfurization temperature is suitable for the desulfurization of hydrocarbons. It cannot be used.

Molecules have many uses in physical, physical chemistry, and chemical processes, and are most suitable as selective adsorbents to complete the separation of components in a mixture and as a catalyst. The use of X-type molecular sieves to remove H ₂ S and mercaptans from natural gas has been applied, but it cannot be used to remove neutral organic sulfides. U.S. Patent No. 5,146,039 proposes a method for removing low-content sulfides in hydrocarbons using a cation-modified molecular sieve. The molecular sieve used in this method uses copper, silver, and zinc as modified cations of type A, X, or Y molecular sieves. In use, only the sulfur concentration Hydrocarbons below 20 ppm are dehydrated under warming conditions, so their sulfur capacity is small. US5057473 proposes a renewable molecular sieve carrier desulfurization adsorbent, using copper and lanthanum as modified cations of 13X molecular sieve, the contact time for ion exchange is 24 and 48 hours, and the temperature of ion exchange is room temperature and 75 ~ 80 ° C, the molecular sieve obtained after the exchange is used to remove the total ^ L of flowing hydrocarbons including hydrogen, in the experiment of removing the fuel of the internal combustion engine at a temperature of about 250 ° C, after 1 An hour's reflux can remove 60% of the total sulfur; this desorbent uses a chemical adsorption method when removing stone gangue, and a corresponding oxidative regeneration method during regeneration, so the regeneration is complicated and the service life is short. Disclosure of invention

The purpose of the present invention is to provide a molecular sieve desulfurizing agent for directly removing organic sulfur compounds in liquefied petroleum gas or light oil by physical adsorption method with large adsorption capacity, high removal rate, convenient regeneration and long life in use. And its preparation method.

The purpose of the present invention is to provide a molecular sieve desulfurizing agent for directly removing organic sulfide in liquefied petroleum gas or light oil by physical adsorption method with large adsorption capacity, high removal rate, convenient regeneration and long life in use. The technical solution is: The molecular sieve desulfurizing agent of the present invention is mainly composed of X-type or Y-type molecular sieves modified with high-valent metal cations, and is characterized in that the elements of high-valent metal cations are lanthanum, cerium or mixed light rare earth Element, the degree of exchange of high-valent metal cations is 70% to 95%.

The degree of exchange of the high-valent metal cations of the modified X-type molecular sieve is 82% to 95%. The degree of exchange of the high-valent metal cations of the modified X-type molecular sieve is preferably 82% to 86%.

The degree of exchange of high-valent metal cations of the modified Y-type molecular sieve is 70% to 75%. The degree of exchange of the high-valent metal cations of the modified Y-type molecular sieve is preferably 70% to 73.5%.

The shape of the finished product of the above-mentioned desulfurizing agent is spherical or cylindrical or sheet-shaped or clover-shaped.

The purpose of the present invention is to provide a method for directly removing organic matter from liquefied petroleum gas or light oil by physical adsorption method with large adsorption capacity, high removal rate, convenient regeneration and long life in use. The technical scheme of the method for preparing sulfide molecular sieve desulfurizing agent is as follows: ① Use X-type or Y-type molecular sieve raw powder; ② Prepare lanthanum, cerium or mixed light rare earth elements with a concentration of 0.05 ~ 0.2mol / l An aqueous solution of high-valent metal cations is used as an exchange liquid. ③ The ion exchange method is used to ion-exchange the original molecular sieve powder with an exchange solution until the exchange-modified high-valent metal cations have an exchange rate of 70% to 95%.

The molecular sieve powder used in the above method is X-type raw powder; the ion exchange method is a reflux type atmospheric pressure ion exchange method, and the reflux time is 2 to 6 hours; the exchanged molecular sieve powder is filtered, dried, roasted, and roasted The time is 2-4 hours, and the roasting temperature is 450 ~ 500 ° C. The ion exchange method is used for the second exchange modification, so that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve reaches 82% to 86%. . The exchange modification and roasting are performed alternately, so that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve can reach 86% to 95%.

The molecular sieve powder used in the above method is a Y-type raw powder; the ion exchange method is a reflux type atmospheric pressure ion exchange method, and the reflux time is 2 to 6 hours; the exchanged molecular sieve powder is filtered, baked, roasted, and roasted The time is 2-4 hours, and the roasting temperature is 450 ~ 550 ° C; the roasted molecular sieve powder is cooled and placed in the above-mentioned exchange liquid, and the second exchange modification is performed by using the above-mentioned reflux type atmospheric pressure ion exchange method, so that The modified Y-type molecular sieve has a high-valent metal cation exchange degree of 70% to 73.5%. The exchange modification and roasting are performed alternately, so that the exchange degree of the high-valent metal cations of the modified Y-type molecular sieve can reach 73.6% to 75%.

The ion exchange method used in the above method is a high pressure ion exchange method. The exchange temperature is maintained at 150 ~ 300 ° C in a high pressure vessel, and the exchange time is> 3 ~ 4 hours, so that the degree of exchange of high-valent metal cations reaches 70% to 95%. .

The molecular sieve raw powder used in the above-mentioned high-pressure ion exchange method is X-type raw powder, and the exchange time is 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 82% to 86%.

The molecular sieve raw powder used in the above-mentioned high-pressure ion exchange method is X-type raw powder, and the exchange time is longer than 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 86% to 95%.

The molecular sieve raw powder used in the above-mentioned high-pressure ion exchange method is a Y-type raw powder, and the exchange time is 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 70% to 73.5%.

The original molecular sieve powder used in the above-mentioned high-pressure ion exchange method is a Y-type original powder, which has a large exchange time. Within 3 to 4 hours, the degree of exchange of high-valent metal cations can reach 73.6% to 75%.

The ion exchange method used in the above method is a continuous atmospheric pressure ion exchange method, which allows the exchange solution to flow from top to bottom through a fixed bed filled with molecular sieve raw powder. The fixed bed temperature is 85 to 95 ° C and the time is 3 to 10 days. , So that the degree of exchange of high-valent metal cations reaches 70% to 86%.

The molecular sieve raw powder used in the continuous atmospheric pressure ion exchange method is an X-type raw powder, and the degree of exchange of high-valent metal cations is 82% to 86%.

The original molecular sieve powder used in the above-mentioned continuous atmospheric pressure ion exchange method is a Y-type original powder, and the degree of exchange of high-valent metal cations is 70% to 73.5%.

The preferred concentration of the exchange solution in the above method is 0.05 to 0.09 mol / l.

The present invention has positive effects: (1) Based on the characteristics of molecular sieves capable of physical adsorption, in order to overcome the shortcomings of low adsorption capacity for neutral organic sulfides, on the one hand, the present invention uses high-valent rare earth metal cations to modify molecular sieves. It can increase the strength of the electrostatic field at the local position in the molecular sieve channels, and make the neutral sulfide molecules in the hydrocarbon stream polarized and easily adsorbed. Therefore, the adsorption capacity and adsorption efficiency of organic sulfides are greatly improved. On the one hand, the control and selection of the rare earth metal cations with a high valence state for the degree of exchange of sodium ions to> 70%, and also greatly improve the adsorption capacity and efficiency of molecular sieves for neutral organic sulfides. (2) Because the molecular sieve of the present invention is suitable for large-capacity physical adsorption and desorption of organic sulfur, especially neutral organic sulfides, after application, the desulfurization rate is high, the sulfur capacity is large, the regeneration cycle is long, and the regeneration The process is also relatively convenient, thereby greatly reducing production costs and operating costs, and making industrial applications possible. The desulfurizing agent of the present invention can be widely used for removing organic sulfur from sulfur-containing hydrocarbon oils such as liquefied petroleum gas, gasoline, kerosene, and diesel oil. It has been verified by industrial practice that its permeation sulfur capacity is greater than 1.5 to 2.5% by weight, and it can be repeatedly regenerated more than 1,000 times. (3) Because the present invention solves the bottleneck problem in the prior art that the molecular sieve technology, which has a small sulfur capacity or a short service life, restricts the industrialization of neutral organic sulfide applications in the refining industry; therefore, the present invention Popularization and application will greatly improve the quality of hydrocarbon oil products (also known as oil products), in order to meet the emerging new social needs and environmental protection requirements.

The best way to implement the invention

The purpose, principle, and effect of the present invention are combined with specific examples and desulfurization effect tests below. For further explanation. However, the content of the present invention is not limited to this at all.

In a specific implementation process, the rare earth metal to be exchanged is prepared into a nitrate or a hydrochloride, and the nitrate or the hydrochloride is made into an aqueous solution as an exchange liquid, and the concentration of the exchange liquid is

The concentration is 0.05 to 0.2 mol / L, preferably 0.05 to 0.09 mol / L. Then the molecular sieve powder is contacted with the exchange liquid phase to make the molecular sieve have the properties. The modification method adopts ① reflux type atmospheric pressure ion exchange method: X-type or Y-type molecular sieve is repeatedly refluxed in the exchange solution, and filtered after one exchange. Wash, dry, roast at high temperature, and then perform the second exchange, and then repeat the exchange many times until the desired exchange degree is reached. Exchange and high-temperature roasting are performed alternately, which can improve the degree of exchange and exchange efficiency. ② Continuous atmospheric pressure ion exchange method: The molecular sieve is packed in a packed column or a fixed bed, and the metal salt solution is continuously passed through the molecular sieve for exchange until the degree of exchange reaches the required requirements. In order to increase the degree of exchange, the packed column can be heated by heat conduction to increase the exchange temperature. The preferred exchange temperature is 81 ° C ~ 95 ° C. ③ The high-pressure ion exchange method, that is, the exchange liquid and the molecular sieve are placed in a closed container, and the ion exchange is performed in a closed system. The temperature can rise to about 150 ~ 300 ° C. At the corresponding temperature, the pressure is also increased accordingly. The exchange process was strengthened, and the exchange degree and exchange efficiency were improved.

Example 1.

Weigh 40 g of commercially available X-type molecular sieve powder with a silicon-aluminum ratio of 2.2 to 3.0, place it in a 500 ml mill-mouth triangle burner, and add 250 ml of a 0.09 mol L lanthanum nitrate solution as an exchange solution. To perform the exchange operation using a reflux type atmospheric pressure ion exchange method: Place the Erlenmeyer flask connected with a reflux tube on an electric furnace and reflux for 4 hours. After cooling, it is filtered, washed, dried, and baked at 490 ° C for 2 ~ 4 hours. After cooling, a second exchange operation was performed. After 3 hours of reflux, the analysis showed that the exchange rate of lanthanum reached 86%.

At this time, the exchanged molecular sieve powder is cooled, taken out, filtered, washed, and dried, and baked at a high temperature of 490 ° C for 2 to 4 hours to obtain a finished product eight.

Example 2,

The rest is the same as in Example 1, except that the exchange solution is a 0.1 mol / L cerium nitrate solution, and the exchange rate of cerium reaches 85% to obtain a finished product B.

Example 3

The rest is the same as in Example 1, except that: the exchange solution is 0.15 mol / L mixed lightly diluted Soil nitrate solution to obtain the finished product C with a mixed light rare earth cation exchange rate of 82.5%. The mixed light rare earth is produced by the rare earth plant of Baotou Iron and Steel Company. In the mixed light rare earth nitrate solution, lanthanum nitrate accounts for about 50%, cerium nitrate accounts for about 45%, and thorium nitrate accounts for about 0.175%.

In order to obtain a higher degree of exchange (for example, from 86% to 95%) of the molecular sieve of this nature, the finished product A, B or C obtained through the two-pass two-bake method of the above embodiments 1 to 3 can be pressed again or multiple times. The same process is performed for exchange and baking until a finished product with the required degree of exchange is obtained.

Example 4,

Weigh 50g of commercially available Y-type molecular sieves with a silicon-aluminum ratio of 3.0 to 5.0 into a 500 ml mill-mouthed conical flask, add 300 ml of a 0.09 mol / L lanthanum nitrate solution as an exchange solution, and use the reflux To perform the exchange operation using a normal-pressure ion exchange method: Place the Erlenmeyer flask connected with a reflux tube on an electric furnace and reflux for 5 hours. After cooling, it is filtered, washed, dried, and baked at 530 ° C for 2 to 4 hours. After cooling, a second exchange operation was performed. After 4 hours of reflux, after analysis, the exchange rate of lanthanum was measured to reach 73.5%. At this time, the exchanged molecular sieve powder was cooled, taken out, filtered, washed, and dried, and calcined at a high temperature of 53 CTC for 2 to 4 hours to obtain a finished product 0.

Example 5.

The rest is the same as in Example 4, except that the exchange solution is a 0.1 mol / L cerium nitrate solution, and the exchange rate of cerium reaches 72%, and a finished product 5 is obtained.

Example 6,

The rest is the same as in Example 4, except that the exchange solution is a mixed light rare earth nitrate solution of 0.15 mol / L, and a finished product F having a mixed light rare earth cation exchange degree of 70.5% is obtained. The mixed light rare earth is produced by the rare earth plant of Baotou Iron and Steel Company. In the mixed light rare earth nitrate solution, lanthanum nitrate accounts for about 50%, cerium nitrate accounts for about 45%, and thorium nitrate accounts for about 0.175%.

In order to obtain the molecular sieve with a higher degree of exchange (for example, from 73.6% to 75%), the finished product D, E, or F obtained by the two-pass two-bake method in the above embodiments 4 to 6 can be pressed again or multiple times. The same process is carried out for exchange and roasting, until a mouthful of exchange rate is obtained.

Example 7,

Weigh 40 g of X-type molecular sieve powder, add it to a 500 ml autoclave, and add 0.11 mol / L 250 ml of lanthanum nitrate solution, the temperature rises to about 250 ° C, the ion exchange takes place in a closed system, and the pressure is correspondingly increased at the corresponding temperature. The exchange time is 4 hours. After natural cooling, filtering, washing, drying, After firing at 480 ° C for 2 hours, the finished product G was obtained. It was determined that the exchange rate of high-valent lanthanum ions for sodium ions reached 88%.

Example 8.

Weigh 40g of Y-type molecular sieve powder, add it to a 500 ml autoclave, add 0.06 mol / L lanthanum nitrate solution 350 ml, the temperature rises to about 250 ° C, ion exchange is performed in a closed system, at the corresponding temperature, The pressure was also increased accordingly. The exchange time was 3.5 hours. After natural cooling, it was filtered, washed, dried, and baked at 550 ° C for 2 hours to obtain the finished product H. It was determined that the exchange rate of high-valent lanthanum ions for sodium ions reached 72%.

Example 9,

Weigh 50g of X-type molecular sieve powder, load the molecular sieve powder in a packed column, and increase the exchange temperature by energizing a heating wire wound outside the packed column (or fixed bed). Control The molecular sieve exchange temperature is around 90 ° C. A 0.06 mol / L lanthanum nitrate solution was prepared, and the lanthanum nitrate solution was continuously dropped into the molecular sieve from top to bottom for exchange. The exchange was continued for 5 days. It was determined that the exchange rate of the high-valent lanthanum ions for sodium ions reached 83%.

Example 10,

Weigh 50g of Y-type molecular sieve powder, load the molecular sieve powder in a packed column, and increase the exchange temperature by energizing a heating wire wound outside the packed column. Control the exchange temperature of the molecular sieve to around 90 ° C. A 0.08 mol / L lanthanum nitrate solution was prepared, and the lanthanum nitrate solution was continuously dropped into the molecular sieve from top to bottom for exchange. The exchange was continued for 6 days. It was determined that the exchange rate of high-valent lanthanum ions for sodium ions reached 70%.

Examples 11 to 16,

Relevant temperature, time, and concentration conditions are the same as those in Embodiments 1 to 6, except that the relevant equipment and material consumption are enlarged by 10 to 100 times. When the second exchange operation is carried out, it is measured that the degree of exchange of high-valent metal ions reaches the required value, and then the cooled molecular sieve powder is taken out, filtered, washed, and baked to about 20% of water, and processed into the required mechanical strength. Spherical, cylindrical, flaky or clover-shaped shapes, and then roasted, can be shipped out of the factory to remove organic sulfur (especially neutral organic phosgene) in the petroleum refining process. Examples 17 to 18,

Relevant temperature, time, and concentration conditions are the same as those in Embodiments 7 to 8, except that the relevant equipment and material consumption are enlarged by 10 to 100 times. When the exchange operation is performed, it is measured that the degree of exchange of the high-valent metal ions reaches the required value, and then the cooled molecular sieve powder is taken out, filtered, washed, and dried to about 20% of water, and processed into a spherical and cylindrical shape with the required mechanical strength. Shape, flake shape, or clover shape, and then roasted to leave the factory for removal of organic stone (especially neutral organic compounds) in the petroleum refining process.

In order to obtain a larger adsorption capacity and a better adsorption effect, the following points should be noted when preparing the desulfurizing agent of the present invention:

① The molecular sieve should be preferably X-type molecular sieve. Compared with X-type and Y-type molecular sieve, X-type molecular sieve has a lower silicon-aluminum ratio and more cations can be exchanged than Y-type molecular sieve. The X-type molecular sieve exchanges more high-valent cations than the Y-type, so the adsorption capacity of the modified X-type molecular sieve is larger than that of the Y-type molecular sieve.

② La ³⁺ is preferred as the exchange ion. Among the high-valent cations used for modification, the molecular sieve after La ³⁺ ion exchange has the strongest polarity, so the adsorption capacity is large.

③ After the exchange, the exchange degree of the X-type molecular sieve is required to be> 82%, and the exchange degree of the Y-type molecular sieve is required to be> 70%. The modified molecular sieve is further processed into a spherical, cylindrical, sheet or clover-shaped desulfurization adsorbent with the required mechanical strength. In order to increase the strength of the desulfurizing agent of the finished product, an appropriate amount of a binder such as sheep glycyrrhizin may be added to the modified molecular sieve powder, and the amount of addition is not more than 30% (wt) of the total weight of the desulfurizing agent.

④ Modification can also use the well-known isomorph substitution method.

Evaluation Trial

Evaluation of desulfurization effect:

The evaluation test of the test desulfurizing agent was performed in a pressure evaluation device. The diameter of the reaction tube was 13 mm, the particle size of the desulfurizing agent was 40 mesh, and the loading amount was 10 ml.

Test conditions: Airspeed: 2h; Temperature: 20 ~ 25 ° C; Pressure: 10 Kgf / cm ² .

Analytical instrument: Microcoulometer (minimum detection amount 0.2ppm).

Experimental raw materials: Mixed carbon four from a refinery was used, with a total sulfur content of 40 ppm, of which H ₂ S content was 3 ppm, and organic sulfur content was 37 ppm. The composition of organic sulfur is: CH ₃ SH, CH ₃ CH; 2SH, C ₃ H ₆ S, C ₄ H ₁₀ S> C ₄ H ₈ S, C ₅ H ₁₂ S, C ₂ H ₆ S ₂ ^ C ₅ H ₁₂ S, C ₃ H ₈ S2, C ₆ H ₁₄ S, C ₇ H ₁₆ S, C ₄ H ₁₀ S ₂ , C ₂ H ₆ S ₃ , C ₄ H ₇ NS, C ₅ H ₁₂ S ₂ . Talented;. G of _{_{_{C 2 H 6 S 2 72%}}} , C 3 H 8 S 2 «8%, C 2 H 6 S 3 - 14% remaining" 6%.

The test results are shown in Table 1.

Table 1: Comparison of removal effect

The evaluation test mainly examines the comparison of the desulfurization effect between different modified samples and the unmodified X-type and Y-type molecular sieves, and the effect of regeneration on the desulfurization effect of the desulfurizer. During the test, when sulfur is detected at the outlet, the desulfurizing agent is considered to have penetrated, and the sulfur capacity at this time is the penetrating sulfur capacity.

From the data in Table 1, it can be seen that the modified molecular sieve has a 5- to 10-fold higher sulfur capacity than the original powder of X-type or Y-type molecular sieve.

Regeneration experiment: Samples A, B, C, D, E, F, G, and H containing stone grams were regenerated with a high-temperature nitrogen purge at 300 ° C. The regeneration space velocity was 500 h " ¹ , and the stones were removed after 50 regenerations. The gram efficiency is still more than 95% of the initial state.

The present invention relates to a molecular sieve type adsorbing and removing agent for finely removing organic sulfides in liquid hydrocarbons, and Its preparation method. The main components of the adsorption desulfurizing agent are modified by high-valent metal cations.

X or Y molecular sieve. The remover can be widely used to remove organic sulfur from various sulfur-containing materials such as liquid hydrocarbons, steam, coal, and diesel. It has been confirmed by industrial experiments that its permeation sulfur capacity is greater than 1.5 to 2.5% (wt), which can be repeatedly regenerated more than 1,000 times. It has the characteristics of high desulfurization accuracy, large capacity, long regeneration period, and long life of desulfurizer, which can greatly reduce Production costs and operating expenses.

Claims

Profit requirements

1. A molecular sieve desulfurizing agent, whose main component is X-type or Y-type molecular sieve modified by high-valent metal cations.

It is characterized in that the element of the high-valent metal cation is lanthanum, cerium or a mixed light rare earth element, and the degree of exchange of the high-valent metal cation is 70% to 95%.

2. The molecular sieve desulfurizing agent according to claim 1,

It is characterized in that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve is 82% to 95%.

3. The molecular sieve desulfurizing agent according to claim 2,

It is characterized in that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve is 82% to 86%.

4. The molecular sieve desulfurizing agent according to claim 1,

It is characterized in that the degree of exchange of high-valent metal cations of the modified Y-type molecular sieve is 70% to 75%.

The molecular sieve desulfurizing agent according to claim 4,

It is characterized in that the degree of exchange of high-valent metal cations of the modified Y-type molecular sieve is 70% to 73.

5%.

6. The molecular sieve desulfurizing agent according to any one of claims 1 to 5,

It is characterized in that the shape of the finished product is spherical or cylindrical or sheet-shaped or clover-shaped.

7. The method for preparing a molecular sieve desulfurizing agent according to claim 1, comprising the following steps: ① selecting X-type or Y-type molecular sieve raw powder; ② preparing lanthanum, cerium or mixed light rare earth with a concentration of 0.05 to 0.2 mol / 1 An aqueous solution of the element's high-valent metal cation is used as the exchange liquid; ③ The ion exchange method is used to ion-exchange the molecular sieve raw powder until the exchange-modified high-valent metal cation has an exchange degree of 70% to 95%.

8. The preparation method according to claim 7,

It is characterized in that: the molecular sieve powder used is X-type raw powder; the ion exchange method is a reflux type atmospheric pressure ion exchange method, and the reflux time is 2 to 6 hours; the exchanged molecular sieve powder is filtered, dried, roasted, and roasted The time is 2 to 4 hours, and the roasting temperature is 450 to 500 ° C; The calcined molecular sieve powder is cooled and put into the above-mentioned exchange liquid, and the second exchange modification is performed by using the above-mentioned reflux type atmospheric pressure ion exchange method, so that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve reaches 82%. ~ 86%.

9. The preparation method according to claim 8,

It is characterized by alternately carrying out exchange modification and roasting, so that the degree of exchange of high-valent metal cations of the modified X-type molecular sieve reaches 86% to 95%.

10. The preparation method according to claim 7,

It is characterized in that: the molecular sieve powder used is a Y-type raw powder; the ion exchange method is a reflux type atmospheric pressure ion exchange method, and the reflux time is 2 to 6 hours; the exchanged molecular sieve powder is filtered, dried, roasted, and roasted The time is 2 to 4 hours, and the calcination temperature is 450 to 550 ° C; the calcined molecular sieve is cooled and placed in the exchange liquid, and the second exchange modification is performed by the above-mentioned reflux type atmospheric pressure ion exchange method. The degree of exchange of high-valent metal cations of the modified Y-type molecular sieve can reach 70% to 73.5%.

11. The preparation method according to claim 10,

It is characterized by alternately carrying out exchange modification and roasting, so that the degree of exchange of high-valent metal cations of the modified Y-type molecular sieve reaches 73.6% to 75%.

12. The preparation method according to claim 7,

It is characterized in that the ion exchange method used is a high-pressure ion exchange method, which keeps the exchange temperature in a high-pressure vessel at 150 ~ 300 ° C, and the exchange time is> 3 ~ 4 hours, so that the degree of exchange of high-valent metal cations reaches 70%-95 %,

13. The preparation method according to claim 12,

It is characterized in that the molecular sieve raw powder is X-type raw powder, and the exchange time is 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 82% to 86%.

14. The preparation method according to claim 12,

It is characterized in that the original molecular sieve powder is X-type original powder, and the exchange time is greater than 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 86% to 95%.

15. The preparation method according to claim 12,

It is characterized in that: the original molecular sieve powder is a Y-type original powder, and the exchange time is 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 70% to 73.5%.

16. The preparation method according to claim 12,

It is characterized in that: the original molecular sieve powder is a Y-type original powder, and the exchange time is greater than 3 to 4 hours, so that the degree of exchange of high-valent metal cations reaches 73.6% to 75%.

17. The preparation method according to claim 7,

It is characterized in that the adopted ion exchange method is a continuous atmospheric pressure ion exchange method, so that the exchange liquid flows from the top to the bottom through a fixed bed containing molecular sieve raw powder, the fixed bed temperature is 85 to 95 ° C, and the time is 3 to 10 It can make the degree of exchange of high-valent metal cations reach 70% to 86%.

18. The preparation method according to claim 17,

It is characterized in that: the original molecular sieve powder is X-type original powder, and the degree of exchange of high-valent metal cations is 82% to 86%.

19. The preparation method according to claim 17,

It is characterized in that: the original molecular sieve powder is a Y-type original powder, and the degree of exchange of high-valent metal cations is 70% to 73.5%.

20. The preparation method according to any one of claims 7 to 19,

It is characterized by: The concentration of the exchange solution is 0.05 ~ 0.09 mol / l.