CN116212866A - A kind of high anti-sulfur CDPF catalyst of low-temperature catalytic soot and preparation method - Google Patents

Abstract

The invention discloses a high-sulfur-resistant CDPF catalyst for low-temperature catalysis of soot and a preparation method thereof. The catalyst comprises: the catalyst is a multi-component active component composite catalyst modified by lanthanum, and the high-sulfur-resistance CDPF catalyst for low-temperature catalysis of soot is The active component of the catalyst is compounded by lanthanum, platinum and palladium, and the platinum-palladium composite base solution is introduced into the lanthanum-modified carrier material made of the lanthanum element salt solution, and the multi-component active component composite type CDPF catalyst is made after drying and roasting . According to the invention, it has excellent low-temperature activity and resistance to sulfur poisoning, significantly reduces the low-temperature light-off temperature T10 of soot by 121°C, and still maintains the advantages of excellent low-temperature activity in a sulfur-containing atmosphere.

Description

A kind of high anti-sulfur CDPF catalyst and preparation method of low-temperature catalytic soot

technical field

The invention relates to the technical field of engine exhaust PM elimination, in particular to a high-sulfur-resistant CDPF catalyst that catalyzes soot at low temperature.

Background technique

Catalyzed diesel particulate filter (CDPF, catalyzed diesel particulate filter) is a passive regeneration technology that reduces the oxidation reaction temperature of particulate matter by coating a catalyst on the wall of diesel particulate filter (DPF, diesel particulate filter). Since precious metals such as Pt and Pd can oxidize NO in engine exhaust to NO2, NO2 is easier to dissociate than O2 to generate active oxygen, and has stronger soot oxidation activity, so it is widely used in CDPF technology. Although CDPF can reduce the regeneration temperature of particulate matter, its regeneration efficiency is generally proportional to the amount of noble metal coating. To obtain better low-temperature soot oxidation activity, the amount of noble metal coating must be increased, resulting in a high cost of the post-treatment system. increase in magnitude.

Patent 202010384153.6 discloses a DPF catalyst with better dispersion. This patent provides a method to make the particle size of the active component of the catalyst smaller, but the active component is one or two of the noble metal platinum and palladium. The problem of precious metal reduction is not addressed.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a high-sulfur-resistant CDPF catalyst for low-temperature catalytic soot and a preparation method thereof, which has excellent low-temperature activity and resistance to sulfur poisoning, and can significantly reduce soot from low-temperature The combustion temperature T10 is reduced by 121°C, and it still maintains the advantages of excellent low-temperature activity in a sulfur-containing atmosphere. In order to realize the above-mentioned purpose and other advantages according to the present invention, a kind of high sulfur resistance CDPF catalyst of low-temperature catalytic soot is provided, comprising:

The active component of the catalyst is compounded by lanthanum, platinum and palladium. The platinum-palladium composite base solution is introduced on the lanthanum-modified carrier material made of lanthanum element salt solution, and the multi-component active component composite CDPF is made after drying and roasting. catalyst.

A kind of preparation method of the high anti-sulfur CDPF catalyst of low-temperature catalytic soot, comprises the following steps:

S1, prepare the lanthanum element salt solution;

S2. Slowly drop the lanthanum element salt solution in step S1 into the carrier powder, so that it is evenly distributed in the porous channels of the carrier;

S3, drying and calcining the lanthanum-modified carrier material in step S2;

S4, further raising the temperature to dry and roast to obtain the lanthanum-modified carrier powder material;

S5, preparation of platinum-palladium composite matrix solution preparation;

S5. Slowly add the platinum-palladium composite base solution to the lanthanum-modified carrier powder material in step S4;

S6. Drying and calcining to obtain a lanthanum-modified multi-component active component composite CDPF catalyst.

Preferably, in step S1, the lanthanum element salt is used as a precursor, and according to requirements, it is added into deionized water at a mass ratio of 0-99%, and the lanthanum element salt solution is prepared after fully stirring and mixing uniformly.

Preferably, in step S3, the drying temperature is 50-100° C., the drying time is 1-6 hours, and the material is dried with moisture.

Preferably, in step S4, the temperature of the oven is increased to above 500° C. and baked for 1 to 6 hours.

Preferably, in step S5, platinum (Pt) and palladium (Pd) salts are used as precursors. According to preset requirements, after calculating and adjusting the ratio of platinum and palladium, the range includes 0 to 1, and accurately measure the corresponding mass of platinum and palladium. Palladium salt, which were added to deionized water in turn, and stirred thoroughly to make it evenly mixed.

Preferably, the lanthanum element salt is lanthanum nitrate, and the lanthanum element salt solution is a lanthanum nitrate solution.

Preferably, the support material is alumina.

Preferably, the salts of platinum (Pt) and palladium (Pd) are platinum nitrate and palladium nitrate.

The present invention compares with prior art, and its beneficial effect is:

(1) The high-sulfur-resistant CDPF catalyst for low-temperature catalytic soot of the present invention has more excellent low-temperature soot catalytic activity and anti-sulfur poisoning than traditional noble metal catalysts. The problem of noble metal reduction in system catalysts offers a solution.

(2) The high-sulfur-resistant CDPF catalyst active component of this kind of low-temperature catalytic soot of the present invention is composed of lanthanum, platinum and palladium, and is introduced into a platinum-palladium composite base on the lanthanum-modified carrier material made from the lanthanum element salt solution The solution is dried and calcined to make a multi-component active component composite CDPF catalyst.

(3) By modifying the platinum-palladium composite-based CDPF catalyst with different proportions of lanthanum, the content of precious metals in the CDPF catalyst can be reduced, and the amount of precious metals can be reduced, providing a solution to the problem of high cost of precious metals in the engine aftertreatment system.

Description of drawings

Fig. 1 is the flowchart according to the high anti-sulfur CDPF catalyst of low-temperature catalytic soot of the present invention and preparation method;

Fig. 2 is a comparative example of a high-sulfur-resistant CDPF catalyst for low-temperature catalytic soot and a preparation method according to the present invention, and a diagram of SEM test results of CDPF catalysts of various embodiments.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Referring to Figure 1-2, a high-sulfur-resistant CDPF catalyst that catalyzes soot at low temperature includes:

The active component of the catalyst is compounded by lanthanum, platinum and palladium. The platinum-palladium composite base solution is introduced on the lanthanum-modified carrier material made of lanthanum element salt solution, and the multi-component active component composite CDPF is made after drying and roasting. catalyst.

A kind of preparation method of the high anti-sulfur CDPF catalyst of low-temperature catalytic soot, comprises the following steps:

S1. Preparation of lanthanum element salt solution: use lanthanum element salt as a precursor, add deionized water according to a certain mass ratio (including 0-99%) according to requirements, stir and mix well to make lanthanum element salt solution ;

S2. Preparation of lanthanum-modified carrier powder: slowly drop the lanthanum element salt solution prepared in the above step S1 into the carrier powder so that it is evenly distributed in the porous channels of the carrier.

S3. Put the lanthanum-modified carrier material dropwise added with the lanthanum element salt solution in step S2 into an oven, the drying temperature is 50-100°C, the drying time is 1-6 hours, and the material is dried;

S4, raising the temperature of the oven in step S3 to above 500° C. and roasting for 1 to 6 hours to obtain the lanthanum-modified carrier powder material;

S5. Platinum-palladium composite base solution preparation: use platinum (Pt) and palladium (Pd) salts as precursors, calculate and adjust the platinum-palladium ratio (ranging from 0 to 1) according to the preset requirements, and then measure it accurately Platinum and palladium salts of corresponding quality are added into deionized water in turn, fully stirred, and mixed evenly;

S6. Slowly add the platinum-palladium composite salt solution obtained in step S5 to the lanthanum-modified carrier powder material obtained in step S4, so that it is evenly distributed in the porous channels of the lanthanum-modified carrier powder material;

S7. Place the lanthanum-modified carrier material obtained in the above step S6 and added dropwise the platinum-palladium compound salt solution in an oven, the drying temperature is 50-100°C, and the drying time is 1-6 hours, the purpose is to dry the material moisture;

S8. Elevate the temperature of the oven to above 500° C. and bake for 1 to 6 hours to finally obtain a lanthanum-modified multi-component active component composite CDPF catalyst.

Comparative example 1

13) In this comparative example, without lanthanum doping, according to the above steps 6) to step 12) to prepare a platinum-palladium composite base CDPF catalyst without lanthanum doping;

14) In this comparative example, the mass ratio of platinum to palladium is 5:1;

15) Table 1 shows the fresh state and sulfurized state activity evaluation test results of the comparative examples obtained by the test of the present invention, and the CDPF catalysts of each embodiment.

16) As shown in Table 1, the characteristic temperatures T10, T50 and T90 of the fresh state lanthanum-free modified platinum-palladium composite base CDPF catalyst are 297 ° C, 393 ° C and 448 ° C, respectively, and the sulfurized state of the non-lanthanum modified platinum-palladium complex base CDPF catalyst The characteristic temperatures T10, T50, and T90 are 413°C, 489°C, and 559°C, respectively. That is to say, after sulfidation, the activity of CDPF catalysts without lanthanum-modified platinum-palladium composite bases is seriously degraded, and the characteristic temperature increases by more than 96°C.

17) Wherein, T10, T50 and T90 refer to the corresponding oxidation characteristic temperature when the soot oxidation rate is 10%, 50% and 90% respectively, which are used to characterize the CDPF catalyst activity, and the lower the value, the better the activity (appears below Its symbolic meaning is the same, so it will not be described again).

18) Fig. 2 shows the SEM test result of comparative example 1 of the present invention and each embodiment CDPF catalyst;

19) As shown in Figure 2, the particle size of the CDPF catalyst in Comparative Example 1 is relatively large, and the degree of dispersion is relatively poor.

Example 1

20) In this preferred embodiment, the mass ratios of the lanthanum and aluminum oxide are respectively 5%:95%;

21) In this preferred embodiment, the mass ratio of platinum to palladium is consistent with Comparative Example 1, adopting 5:1;

22) It can be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 1 modified by 5% lanthanum in the fresh state are 302°C, 402°C and 458°C respectively, that is to say, compared with Comparative Example 1, the characteristic values of Example 1 The temperature increases slightly, and the increase is less than 10°C;

23) It can also be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 1 modified by 5% lanthanum in the sulfide state are 372°C, 493°C and 600°C respectively. Compared with Comparative Example 1, the characteristic temperature T10 of Example 1 is lower That is to say, the low-temperature catalytic activity of Example 1 modified by 5% lanthanum is slightly reduced, but the sulfided sample after being poisoned by 100ppmSO2 atmosphere shows excellent low-temperature soot catalytic oxidation activity.

24) As can be seen from Figure 2, the CDPF catalyst of Example 1 has a smaller particle size than the comparative example 1 without lanthanum modification, and better dispersion and particle size uniformity.

Example 2

25) In this preferred embodiment, the mass ratios of the lanthanum and alumina are respectively 10%:90%;

26) In this preferred embodiment, the mass ratio of platinum to palladium is consistent with Comparative Example 1, adopting 5:1;

27) It can be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 2 modified by 10% lanthanum in the fresh state are 292°C, 403°C and 458°C respectively, that is to say, compared with Comparative Example 1, the fresh state of Example 2 The eigenvalue temperature T10 decreased by 5°C, showing excellent low-temperature soot catalytic activity;

28) It can also be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 2 modified with 10% lanthanum in the sulfide state are 398°C, 504°C and 599°C, respectively. Compared with Comparative Example 1, the characteristic temperature in the sulfide state of Example 2 T10 was lowered by 15°C, and it still showed good low-temperature soot catalytic activity. That is to say, the fresh state and the sulfurized state of Example 2 modified by 10% lanthanum all show excellent low-temperature catalytic activity compared with Comparative Example 1;

29) As can be seen from Figure 2, the CDPF catalyst of Example 2 has a smaller particle size than the comparative example 1 without lanthanum modification, and the degree of dispersion and particle size uniformity are significantly improved.

Example 3

In this preferred embodiment, the mass ratios of the lanthanum and alumina are respectively 20%:80%;

In this preferred embodiment, the mass ratio of platinum to palladium is consistent with Comparative Example 1, adopting 5:1;

It can be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 3 modified by 20% lanthanum in the fresh state are 176°C, 383°C and 620°C respectively, that is to say, compared with Comparative Example 1, the characteristic temperature of Example 3 is significantly Reduced, T10 decreased by 121°C, T50 decreased by 10°C, showing excellent low-temperature soot catalytic activity;

It can also be seen from Table 1 that the characteristic temperatures T10, T50 and T90 of Example 3 modified with 20% lanthanum in the sulfide state are 403°C, 499°C and 595°C, respectively. That is to say, the catalytic oxidation activity of the low-temperature soot in the sulfide state of Example 3 after being poisoned by 100ppm SO2 atmosphere is still better than that of Comparative Example 1.

It can be seen from FIG. 2 that the CDPF catalyst of Example 3 is better in particle size, dispersion and particle size uniformity than Comparative Example 1 without lanthanum modification.

The CDPF catalyst fresh state of table 1 comparative example, each embodiment and sulfurized state characteristic temperature value

The number of devices and processing scale described here are used to simplify the description of the present invention, and the application, modification and variation of the present invention will be obvious to those skilled in the art.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Further modifications can be effected, so the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (9)

1. a kind of high anti-sulfur CDPF catalyst of low-temperature catalytic soot, it is characterized in that, comprises: The active component of the catalyst is compounded by lanthanum, platinum and palladium. The platinum-palladium composite base solution is introduced on the lanthanum-modified carrier material made of lanthanum element salt solution, and the multi-component active component composite CDPF is made after drying and roasting. catalyst. 2. the preparation method of the high anti-sulfur CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 1, is characterized in that, comprises the following steps: S1, prepare the lanthanum element salt solution; S2. Slowly drop the lanthanum element salt solution in step S1 into the carrier powder, so that it is evenly distributed in the porous channels of the carrier; S3, drying and calcining the lanthanum-modified carrier material in step S2; S4, further raising the temperature to dry and roast to obtain the lanthanum-modified carrier powder material; S5, preparation of platinum-palladium composite matrix solution preparation; S5. Slowly add the platinum-palladium composite base solution to the lanthanum-modified carrier powder material in step S4; S6. Drying and calcining to obtain a lanthanum-modified multi-component active component composite CDPF catalyst. 3. The high sulfur resistance CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 2, it is characterized in that, in step S1, lanthanum element salt is used as precursor, according to demand, by the mass ratio of 0～99% Add it into deionized water, stir well and mix evenly to make a lanthanum element salt solution. 4. the high sulfur resistance CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 3, it is characterized in that, in step S3, drying temperature is 50～100 ℃, and drying time is 1～6 hours, and material moisture drying. 5 . A high-sulfur-resistant CDPF catalyst that catalyzes soot at low temperature as claimed in claim 4 , characterized in that, in step S4, the temperature of the oven is increased to above 500° C. and roasted for 1 to 6 hours. 6 . 6. the high anti-sulfur CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 5, is characterized in that, step S5 uses platinum (Pt) and palladium (Pd) salt material as precursor, according to preset Requirements, after calculating and adjusting the ratio of platinum and palladium, the range includes 0 to 1, accurately measure the corresponding mass of platinum and palladium salts, add them to deionized water in turn, and stir well to make them evenly mixed. 7. The high sulfur-resistant CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 6, is characterized in that, the lanthanum element salt class material adopts lanthanum nitrate, and the lanthanum element salt solution is a lanthanum nitrate solution. 8. the high sulfur resistance CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 7, it is characterized in that, support material is aluminum oxide. 9. the high anti-sulfur CDPF catalyst of a kind of low-temperature catalytic soot as claimed in claim 8, is characterized in that, platinum (Pt) and palladium (Pd) salts are platinum nitrate, palladium nitrate.

Images