Gasoline engine particle trap with low backpressure amplification and narrow pore size distribution and preparation method thereof

Abstract

The invention discloses a gasoline engine particle trap with low back pressure amplification and narrow pore size distribution and a preparation method thereof, and belongs to the technical field of gasoline engine tail gas emission treatment. The preparation method comprises the following steps: mixing an inorganic raw material, a pore-forming agent, a binder and water to prepare a pug, carrying out pugging, extrusion molding, microwave drying and high-temperature sintering to prepare a ceramic matrix, and carrying out pore plugging and catalyst coating on the ceramic matrix to prepare the gasoline engine particle trap. Wherein the median particle size D50 of a mixture formed by mixing the inorganic raw materials, the pore forming agent and the binder is controlled to be within the range of 20-26 microns, the span (D90-D10) / D50 is smaller than 1.4, and the gasoline engine particle trap with the back pressure amplification being 13-56% is obtained. According to the method, the pore size distribution condition of the ceramic matrix can be pre-judged in actual production, so that particle distribution adjustment of raw materials is carried out, and the pore size consistency of gasoline engine particle traps produced in batches is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of gasoline engine tail gas emission control, and more specifically, relates to a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution and a preparation method thereof. Background Art

[0002] As emission regulations become increasingly stringent, the newly promulgated "National VI" emission standards have lower limits on various pollutants compared to the current "National V" emission standards; for gasoline engines, new PN limit requirements have been added, which are more stringent on the cleanliness of exhaust emissions; most OEMs use particulate filters to filter carbon soot particles in exhaust gas for post-treatment of diesel engines, so that the exhaust emissions meet the requirements of emission regulations; compared with diesel engines, gasoline engines have higher speeds and require smoother exhaust, thereby reducing the impact on engine power. In this way, the requirements for gasoline engine particulate filters must meet the PN limit of 6.0×1011 pieces / km and meet a smaller exhaust back pressure. For gasoline engine particulate filters under such use conditions, high porosity, suitable pore size, and narrow pore size distribution are required, and mechanical strength that meets the requirements of assembly and use is also required.

[0003] The porosity of diesel engine particulate filters is generally 40% to 50%, the median pore size is generally 8 to 15μm, the strength required for assembly is generally greater than 1.0Mpa, and the strength of diesel engine particulate filters is generally 3 to 5Mpa; the porosity of gasoline engine particulate filters is generally 60 to 70%, the median pore size is generally 16 to 23μm, and the mechanical strength is generally 1.5 to 3MPa.

[0004] During the use of gasoline engine particulate filters, especially in the catalyst coating process, the narrower the pore size distribution of the ceramic substrate, the smaller the increase in back pressure of the gasoline engine particulate filter after loading the catalyst; therefore, for the National VI gasoline engine after-treatment system, a particulate filter with high porosity and narrow pore size distribution is currently required to minimize the impact on engine exhaust resistance while meeting the National VI emission standards.

[0005] Patent CN113860852A discloses a cordierite gasoline engine particulate filter and a preparation method thereof, wherein the main raw materials include: 37-43wt% talc, 12-25wt% kaolin, 0.1-30wt% alumina, 0.1-20wt% silicon oxide, 0.01-5wt% cordierite powder; based on the main material as 100wt%, the auxiliary materials include: 0-5wt% dispersant, 0-10wt% extrusion aid, 0-10wt% adhesive + plasticizer, 0-65wt% pore former, and 22-26wt% water. This patent uses raw materials commonly used in cordierite ceramics, and the proportions are calculated based on cordierite as the target for calculating the amounts of various raw materials. Although there are requirements for the particle sizes of various raw materials, there are no requirements for the particle size of the pore-forming agent used. There are no requirements for the pore-forming agent, which is the main factor that determines the narrow pore size distribution of the final ceramic carrier. Therefore, changes in the particle size of the pore-forming agent will make it difficult for the final ceramic carrier to achieve the required narrow pore size distribution.

[0006] Patent CN112047720A discloses a method for preparing a high-porosity particle collector, which is made by the following steps: 10-60% starch-based pore-forming material, 0.1-30% organic ball pore-forming material, and 5-30% carbon source pore-forming material are mixed to form a pore-forming material; 40-45% talc, 10-20% kaolin, 20-30% alumina, and 10-15% silicon oxide are mixed to form an inorganic raw material; then the inorganic raw material and the pore-forming material are mixed in a ratio of 10:2-5, and 6-10% of a binder and 1-2% of a lubricant are added, and then 20-30% of water is added and stirred thoroughly; the above materials are extruded through an extruder; the honeycomb ceramic embryo is dried through a dryer; the dried honeycomb ceramic embryo is placed in a sintering furnace, the temperature is gradually increased from room temperature to 1420°C, the temperature is increased by 30°C per hour, and then the temperature is kept constant at 1420°C for 8 hours. This patent does not provide any selection of raw materials and particle collectors, and does not provide any preparation of particle collectors with narrow pore distribution.

[0007] Patent CN109796221A discloses a gasoline engine exhaust particulate filter, including a main material and a sealing material, wherein both the main material and the sealing material include alumina, talc, aluminum hydroxide, kaolin, quartz powder, pore formers and water, and the pore former content of the sealing material is 1.05 to 1.10 times the pore former content of the main material. The main material is mixed in a weight ratio of 15 to 20:15 to 25:35 to 45:15 to 20:10 to 20:10 to 20. The pore former includes at least one of organic resin microspheres and graphite, and the particle size is 3 to 10 μm. The patent prepares a highly porous ceramic matrix, but does not test the back pressure of its product. Summary of the invention

[0008] In view of the above-mentioned problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution, by controlling the particle size and particle size distribution of the mixture after mixing the inorganic raw material, pore-forming agent and binder, a ceramic matrix of the particulate filter with optimal pore size distribution is obtained, and then a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution is obtained; another technical problem to be solved by the present invention is to provide a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution prepared by the preparation method.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0010] A preparation method for a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution, comprising: mixing an inorganic raw material, a pore former, a binder and water to obtain a mud material, kneading the mud, extruding, microwave drying and high-temperature sintering to obtain a ceramic matrix, and plugging the pores of the ceramic matrix and coating the catalyst to obtain a gasoline engine particulate filter; wherein, by controlling the median particle size D50 of the mixture after the inorganic raw material, the pore former and the binder are mixed within the range of 20 to 26 μm and the span (D90-D10) / D50 < 1.4, a gasoline engine particulate filter with a back pressure increase of 13 to 56% is obtained.

[0011] The median particle size D50 of the mixture = [0.729×inorganic raw material D50+0.65×pore former D50×pore former wt%] / 0.898.

[0012] Preferably, the porosity of the ceramic matrix is ​​50-70%, the pore volume is 0.50-0.75 mL / g, the median particle size D50 is 16-22 μm, the pore size distribution of less than 5 μm accounts for less than 1%, the pore size distribution of not less than 40 μm accounts for 7-10%, the pore size distribution of 10-30 μm accounts for 80-85%, and the pore size D[4,3] is equal to 0.90-1.0 times D50.

[0013] The ceramic matrix consists of inorganic raw materials, pore-forming agent, binder and water.

[0014] Preferably, the median particle size D50 of the inorganic raw material is 13-16 μm, and the span (D90-D10) / D50 is less than 1.5.

[0015] Preferably, the median particle size D50 of the pore-forming agent is 35-40 μm, and the span (D90-D10) / D50 is less than 0.9.

[0016] Preferably, the inorganic raw materials consist of talc, kaolin, alumina, quartz powder and activated alumina.

[0017] Preferably, the pore-forming agent is selected from one or more of starch, graphite, carbon powder, and organic plastic particles; the binder is selected from one or more of cellulose ether, HPMC, CMC, CMMC, and PVA.

[0018] A method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution comprises the following steps:

[0019] 1) Mixing the inorganic raw materials, pore-forming agent, binder and water in a mixer to obtain a mud material;

[0020] 2) The clay obtained in step 1) is kneaded, extruded, microwave dried, and sintered at high temperature to obtain a ceramic substrate with a diameter of 132 mm, a length of 127 mm, a pore density of 300 holes, and a wall thickness of 0.2 mm;

[0021] 3) cross-blocking the honeycomb holes at both ends of the ceramic substrate obtained in step 2), wherein the mud used for blocking the holes is composed of cordierite powder, quartz powder and silica sol, to obtain a blank gasoline engine particulate filter;

[0022] 4) The blank gasoline engine particulate filter obtained in step 3) is coated with 120 g / L of catalyst to obtain a gasoline engine particulate filter.

[0023] Preferably, in step 3), the plugging depth is 3 to 10 mm.

[0024] The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution can prepare a gasoline engine particulate filter.

[0025] The gasoline engine particulate collector has a porosity of 53-63%.

[0026] The present invention uses talc, kaolin, alumina, quartz powder and activated alumina as raw materials. Cordierite (2MgO·2Al2O3·5SiO2) is used as the theoretical ratio, and the amount of various raw materials is calculated according to the mass percentage of the constituent elements of cordierite (MgO: 13.7Wt%, Al2O3: 34.9Wt%, SiO2: 51.4Wt%). Talc is used to provide magnesium in cordierite, kaolin can improve the plasticity of the mud material and facilitate molding, activated alumina can improve the reaction activity of the mixed raw materials during firing and facilitate firing, and quartz and alumina are used to make up for the missing elements.

[0027] Taking the mass percentage of cordierite components (MgO: 13.7Wt%, Al2O3: 34.9Wt%, SiO2: 51.4Wt%) as the target ratio, according to the characteristics of the chemical composition of various raw materials, and the physical properties of various raw materials and the preparation process characteristics within the scope of this technology, the basic formula is generally prepared as follows: talc 38.6Wt%, kaolin 9.5Wt%, aluminum hydroxide 18.7Wt%, aluminum oxide 15.1Wt%, quartz 18.1Wt%. The prepared inorganic raw materials are mixed with pore-forming agents, adhesives, and water to form a mud material, and then the semi-finished mud blank is obtained through mud kneading, extrusion molding, and drying, and then the ceramic matrix is ​​obtained through sintering and high-level processing.

[0028] The porosity and pore size distribution in the ceramic matrix of gasoline engine particulate filter are mainly formed by two parts, one is formed by inorganic raw material powder during sintering, and the other is formed by organic pore formers. In the formulation of the ceramic matrix, the porosity and pore size distribution formed by the inorganic raw materials as well as the porosity and pore size distribution formed by the pore formers must be considered, and the matching relationship between the porosity and pore size distribution formed by the two must also be taken into account; in order to obtain a ceramic matrix with high porosity, suitable pore size, and narrow pore size distribution.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1) The present invention can control the pore size distribution of the ceramic matrix by adjusting the gradation relationship between the particle distribution of the inorganic mixed raw material and the particle size distribution of the organic pore-forming agent; finally, the relationship between the particle distribution of the inorganic mixed material and the particle distribution of the pore-forming agent and the dosage is fitted, and the pore size distribution of the ceramic matrix can be pre-determined in actual production, so as to adjust the particle distribution of the raw material to ensure the consistency of the pore size of gasoline engine particulate filters produced in batches;

[0031] 2) The present invention adjusts and controls the particle size and particle distribution of the ridge raw material in the inorganic raw material to obtain a better inorganic ceramic blank matrix; and then adjusts and controls the particle size and particle distribution of the pore-forming agent in combination with the inorganic formula to obtain a ceramic matrix of the particle collector with the optimal pore size distribution;

[0032] 3) The present invention can control the pore size distribution of the ceramic matrix by adjusting the relationship between the inorganic raw material and the pore-forming agent, reduce the proportion of fine pores and macropores, increase the proportion of effective porosity, and obtain a ceramic matrix with narrower pore distribution;

[0033] 4) The present invention can predict the pore size distribution of the ceramic matrix made from the mixture through the particle size and particle size distribution, thereby shortening the research and development cycle, determining the feasibility of the formula more quickly, and reducing research and development costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1This is a schematic diagram of the product structure prepared in Example 3 of the present invention;

[0035] Figure 2 The relationship between the particle size of the mixed materials and the pore size of the ceramic matrix of Examples 1 to 19 and Comparative Examples 1 to 8;

[0036] Figure 3 The relationship diagram between the particle size distribution of the mixture and the pore size distribution of the ceramic matrix of Examples 1 to 19 and Comparative Examples 1 to 8;

[0037] Figure 4 It is a relationship diagram between the pore size distribution of the ceramic substrate and the collector back pressure increase of Examples 1 to 19 and Comparative Examples 1 to 8. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. In the following examples, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0039] In the following examples, the particle size and distribution of the raw materials used are shown in the following table (the following data are measured by a laser particle size analyzer):

[0040]

[0041]

[0042] Chemical composition of raw materials used:

[0043]

[0044] The inorganic raw material components in the formula used are shown in the following table:

[0045]

[0046] The particle size and distribution of the inorganic mixed mud used are shown in the following table:

[0047] Recipe Number D10(μm) D50(μm) D90(μm) Span 1# 3.15 12.41 23.56 1.64 2# 4.15 12.94 23.75 1.51 3# 4.87 13.25 24.24 1.46 4# 4.57 13.06 24.02 1.49 5# 5.87 15.54 28.84 1.48 6# 6.21 15.27 28.16 1.44 7# 6.22 16.89 33.58 1.62 8# 6.99 16.11 33.15 1.62

[0048] Example 1

[0049] A method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution comprises the following steps:

[0050] 1) 38.6wt% of talc-A, 9.5wt% of kaolin, 18.7wt% of aluminum hydroxide, 15.1wt% of aluminum oxide-A, and 18.1wt% of quartz-B are mixed in a mixer to form an inorganic raw material (6#); 7.5wt% of cellulose ether and 38wt% of starch-1 are added on the basis of the weight of the inorganic raw materials to mix and obtain ingredients; and 22wt% of deionized water is added on the basis of the total weight of the ingredients to form a slurry;

[0051] 2) The clay obtained in step 1) is subjected to vacuum kneading with a vacuum degree of less than -95 Kpa, extruded at an extrusion pressure of 15 to 25 MPa, microwave dried until the moisture content of the clay is less than 1%, and calcined at a high temperature at 1420° C. for 15 hours to obtain a gasoline engine particulate filter ceramic matrix with a diameter of 132 mm, a length of 127 mm, a pore density of 300 pores, and a wall thickness of 0.2 mm;

[0052] 3) plugging the pores of the gasoline engine particulate filter ceramic substrate obtained in step 2) by using cordierite powder, quartz powder and silica sol to prepare a plugging mud material, wherein the viscosity of the mud material is 80000-100000 mPa·s, and cross-plugging is performed on both ends of the ceramic substrate, and the plugging depth is 5 mm, thereby obtaining a blank gasoline engine particulate filter;

[0053] 4) The blank gasoline engine particulate filter obtained in step 3) is coated with 120 g / L of LaO rare earth metal catalyst to obtain a gasoline engine particulate filter.

[0054] Example 2

[0055] When preparing a gasoline engine particulate filter, the amount of starch-1 added in step 1) is 40 wt %, and the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0056] Example 3

[0057] When preparing a gasoline engine particulate filter, the amount of starch-1 added in step 1) is 42 wt %, and the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0058] Example 4

[0059] When preparing a gasoline engine particulate filter, the amount of starch-1 added in step 1) is 44 wt %, and the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0060] Example 5

[0061] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-2, and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0062] Example 6

[0063] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-3, and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0064] Example 7

[0065] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-4, and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0066] Example 8

[0067] When preparing a gasoline engine particulate filter, the preparation process of the inorganic raw material in step 1) is: 38.6Wt% talc-B, 9.5Wt% kaolin, 18.7Wt% aluminum hydroxide, 15.1Wt% alumina-A, and 18.1Wt% quartz-A are mixed by a mixer to form an inorganic raw material (3#), and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0068] Example 9

[0069] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-2, and the remaining preparation methods and parameters are the same as those in Example 8 to obtain a gasoline engine particulate filter.

[0070] Example 10

[0071] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-3, and the remaining preparation methods and parameters are the same as those in Example 8 to obtain a gasoline engine particulate filter.

[0072] Embodiment 11

[0073] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-4, and the remaining preparation methods and parameters are the same as those in Example 8 to obtain a gasoline engine particulate filter.

[0074] Example 12

[0075] When preparing a gasoline engine particulate filter, the preparation process of the inorganic raw material in step 1) is: 38.6Wt% talc-B, 9.5Wt% kaolin, 18.7Wt% aluminum hydroxide, 15.1Wt% alumina-B, and 18.1Wt% quartz-A are mixed by a mixer to form an inorganic raw material (4#), and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0076] Embodiment 13

[0077] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-2, and the remaining preparation methods and parameters are the same as those in Example 12 to obtain a gasoline engine particulate filter.

[0078] Embodiment 14

[0079] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-3, and the remaining preparation methods and parameters are the same as those in Example 12 to obtain a gasoline engine particulate filter.

[0080] Embodiment 15

[0081] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-4, and the remaining preparation methods and parameters are the same as those in Example 12 to obtain a gasoline engine particulate filter.

[0082] Example 16

[0083] When preparing a gasoline engine particulate filter, the preparation process of the inorganic raw material in step 1) is: 38.6Wt% talc-A, 9.5Wt% kaolin, 18.7Wt% aluminum hydroxide, 15.1Wt% alumina-B, and 18.1Wt% quartz-B are mixed by a mixer to form an inorganic raw material (5#), and the remaining preparation methods and parameters are the same as those in Example 3 to obtain a gasoline engine particulate filter.

[0084] Embodiment 17

[0085] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-2, and the remaining preparation methods and parameters are the same as those in Example 16 to obtain a gasoline engine particulate filter.

[0086] Embodiment 18

[0087] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-3, and the remaining preparation methods and parameters are the same as those in Example 16 to obtain a gasoline engine particulate filter.

[0088] Embodiment 19

[0089] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-4, and the remaining preparation methods and parameters are the same as those in Example 16 to obtain a gasoline engine particulate filter.

[0090] Comparative Example 1

[0091] When preparing a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-B are mixed by a mixer to form an inorganic raw material (2#); 7.5 wt% cellulose ether and 42 wt% starch-1 are added on the basis of the weight of the inorganic raw materials and mixed to obtain ingredients; 22 wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0092] Comparative Example 2

[0093] When preparing a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-B are mixed by a mixer to form an inorganic raw material (2#); 7.5 wt% cellulose ether and 42 wt% starch-2 are added on the basis of the weight of the inorganic raw materials to mix and obtain ingredients; 22 wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0094] Comparative Example 3

[0095] When preparing a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-B are mixed by a mixer to form an inorganic raw material (2#); 7.5 wt% cellulose ether and 42 wt% starch 3- are added on the basis of the weight of the inorganic raw materials to mix and obtain ingredients; 22 wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0096] Comparative Example 4

[0097] When preparing a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-B are mixed by a mixer to form an inorganic raw material (2#); 7.5 wt% cellulose ether and 42 wt% starch-4 are added on the basis of the weight of the inorganic raw materials and mixed to obtain ingredients; 22 wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0098] Comparative Example 5

[0099] When preparing a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-A, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-A are mixed by a mixer to form an inorganic raw material (7#); 7.5 wt% cellulose ether and 42 wt% starch-1 are added on the basis of the weight of the inorganic raw materials to mix and obtain ingredients; 22 wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a gasoline engine particulate filter.

[0100] Comparative Example 6

[0101] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-2, and the remaining preparation methods and parameters are the same as those in comparative example 5 to obtain a gasoline engine particulate filter.

[0102] Comparative Example 7

[0103] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-3, and the remaining preparation methods and parameters are the same as those in comparative example 5 to obtain a gasoline engine particulate filter.

[0104] Comparative Example 8

[0105] When preparing a gasoline engine particulate filter, the pore-forming agent selected in step 1) is starch-4, and the remaining preparation methods and parameters are the same as those in comparative example 5 to obtain a gasoline engine particulate filter.

[0106] Comparative Example 9

[0107] When preparing a ceramic matrix for a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-B, and 18.1 wt% quartz-B are mixed in a mixer to form an inorganic raw material (1#); 7.5 wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain a batch; 22 wt% deionized water is added on the basis of the total weight of the batch to form a mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a ceramic matrix for a gasoline engine particulate filter.

[0108] Comparative Example 10

[0109] When preparing the ceramic matrix of the gasoline engine particulate filter, the preparation process of the mud in step 1) is: 38.6wt% talc-B, 9.5wt% kaolin, 18.7wt% aluminum hydroxide, 15.1wt% aluminum oxide-A, and 18.1wt% quartz-B are mixed by a mixer to form an inorganic raw material (2#); 7.5wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain ingredients; 22wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain the ceramic matrix of the gasoline engine particulate filter.

[0110] Comparative Example 11

[0111] When preparing a ceramic matrix for a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-A are mixed in a mixer to form an inorganic raw material (3#); 7.5 wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain a batch; 22 wt% deionized water is added on the basis of the total weight of the batch to form a mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a ceramic matrix for a gasoline engine particulate filter.

[0112] Comparative Example 12

[0113] When preparing a ceramic matrix for a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-B, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-B, and 18.1 wt% quartz-A are mixed in a mixer to form an inorganic raw material (4#); 7.5 wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain a batch; 22 wt% deionized water is added on the basis of the total weight of the batch to form a mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a ceramic matrix for a gasoline engine particulate filter.

[0114] Comparative Example 13

[0115] When preparing the ceramic matrix of the gasoline engine particulate filter, the preparation process of the mud in step 1) is: 38.6wt% talc-A, 9.5wt% kaolin, 18.7wt% aluminum hydroxide, 15.1wt% aluminum oxide-B, and 18.1wt% quartz-B are mixed by a mixer to form an inorganic raw material (5#); 7.5wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain ingredients; 22wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain the ceramic matrix of the gasoline engine particulate filter.

[0116] Comparative Example 14

[0117] When preparing a ceramic matrix for a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-A, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-B are mixed in a mixer to form an inorganic raw material (6#); 7.5 wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain a batch; 22 wt% deionized water is added on the basis of the total weight of the batch to form a mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a ceramic matrix for a gasoline engine particulate filter.

[0118] Comparative Example 15

[0119] When preparing a ceramic matrix for a gasoline engine particulate filter, the preparation process of the mud in step 1) is as follows: 38.6 wt% talc-A, 9.5 wt% kaolin, 18.7 wt% aluminum hydroxide, 15.1 wt% alumina-A, and 18.1 wt% quartz-A are mixed in a mixer to form an inorganic raw material (7#); 7.5 wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain a batch; 22 wt% deionized water is added on the basis of the total weight of the batch to form a mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain a ceramic matrix for a gasoline engine particulate filter.

[0120] Comparative Example 16

[0121] When preparing the ceramic matrix of the gasoline engine particulate filter, the preparation process of the mud in step 1) is: 38.6wt% talc-A, 9.5wt% kaolin, 18.7wt% aluminum hydroxide, 15.1wt% aluminum oxide-B, and 18.1wt% quartz-A are mixed by a mixer to form an inorganic raw material (8#); 7.5wt% cellulose ether is added on the basis of the weight of the inorganic raw materials and mixed to obtain ingredients; 22wt% deionized water is added on the basis of the total weight of the ingredients to form mud; the remaining preparation methods and parameters are the same as those in Example 1 to obtain the ceramic matrix of the gasoline engine particulate filter.

[0122] The porosity and pore size distribution of the gasoline engine particulate filter ceramic substrates prepared in Examples 1-19 and Comparative Examples 1-16 were tested using a mercury intrusion instrument to determine the quality of their formulation porosity and pore size distribution. The back pressure of the gasoline engine particulate filter prepared in Examples 1-19 and Comparative Examples 1-8 before and after the catalyst was coated was measured using a back pressure measuring instrument to determine the back pressure increase of the particulate filter. The results are shown in Tables 1 to 7 below.

[0123] Table 1 Particle size distribution results of the ceramic matrix of gasoline engine particulate filter prepared in Examples 1-10

[0124]

[0125] Table 2 Particle size distribution results of the ceramic matrix of gasoline engine particulate filter prepared in Examples 11-19

[0126]

[0127]

[0128] Table 3 Particle size distribution results of the ceramic matrix of gasoline engine particulate filter prepared in Comparative Examples 1-8

[0129]

[0130] Table 4 Porosity and pore size distribution results of the ceramic matrix of gasoline engine particulate filter prepared in Comparative Examples 9-16

[0131]

[0132] Table 5 Porosity and pore size distribution and back pressure test results of the gasoline engine particulate filter ceramic substrate prepared in Examples 1-10

[0133]

[0134]

[0135] Table 6 Porosity and pore size distribution and back pressure test results of the gasoline engine particulate filter ceramic substrate prepared in Examples 11-19

[0136]

[0137]

[0138] Table 7 Porosity and pore size distribution and back pressure test results of gasoline engine particulate filter ceramic substrates prepared in Comparative Examples 1-8

[0139]

[0140]

[0141] It can be seen from Tables 1-7 that by controlling the relationship between the particle size distribution of the inorganic mixture and the particle size distribution of the pore-forming agent, a carrier for a gasoline engine particulate filter with a lower back pressure increase can be prepared.

[0142] Depend on Figure 2 It can be seen that the particle size of the mixture is linearly related to the pore size of the ceramic substrate. When the mixture is within a certain range, the pore size of the ceramic carrier can be predicted.

[0143] Depend on Figure 3It can be seen that the lower the particle size distribution of the mixture is, the lower the pore size distribution of the ceramic matrix can be obtained. When the particle size distribution of the mixture is within a certain range, the pore size distribution of the ceramic carrier made therefrom can be determined.

[0144] Depend on Figure 4 It can be seen that when the pore size distribution of the ceramic carrier is close to 1, the back pressure after coating the catalyst is lower. When preparing a ceramic matrix with a lower back pressure increase, it can be predicted by the pore size distribution of the ceramic matrix.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution, characterized in that: An inorganic raw material, a pore-forming agent, a binder and water are mixed to obtain a mud material, which is then kneaded, extruded, microwave dried and sintered at high temperature to obtain a ceramic matrix, which is then plugged and coated with a catalyst to obtain a gasoline engine particulate filter; wherein, by controlling the median particle size D50 of the mixture after the inorganic raw material, the pore-forming agent and the binder are mixed within the range of 20 to 26 μm and the span (D90-D10) / D50 < 1.4, a gasoline engine particulate filter with a back pressure increase of 13 to 56% is obtained.

2. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 1, characterized in that: The porosity of the ceramic matrix is ​​50-70%, the pore volume is 0.50-0.75 mL / g, the median pore diameter D50 is 16-22 μm, the pore diameter with a pore diameter distribution of less than 5 μm accounts for less than 1%, the pore diameter with a pore diameter distribution of not less than 40 μm accounts for 7-10%, and the pore diameter with a pore diameter distribution of 10-30 μm accounts for 80-85%.

3. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 1, characterized in that: The median particle size D50 of the inorganic raw material is 13-16 μm, and the span (D90-D10) / D50 is less than 1.

5.

4. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 1, characterized in that: The median particle size D50 of the pore former is 35-40 μm, and the span (D90-D10) / D50 is less than 0.

9.

5. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 1, characterized in that: The inorganic raw materials consist of talc, kaolin, alumina, quartz powder and activated alumina.

6. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 1, characterized in that: The pore-forming agent is selected from one or more of starch, graphite, carbon powder, and organic plastic particles; the binder is selected from one or more of cellulose ether, HPMC, CMC, CMMC, and PVA.

7. A method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution, characterized in that: The specific steps include: 1) Mixing the inorganic raw materials, pore-forming agent, binder and water in a mixer to obtain a mud material; 2) The clay obtained in step 1) is kneaded, extruded, microwave dried, and sintered at high temperature to obtain a ceramic substrate with a diameter of 132 mm, a length of 127 mm, a pore density of 300 holes, and a wall thickness of 0.2 mm; 3) cross-blocking the honeycomb holes at both ends of the ceramic substrate obtained in step 2), wherein the mud used for blocking the holes is composed of cordierite powder, quartz powder and silica sol, to obtain a blank gasoline engine particulate filter; 4) The blank gasoline engine particulate filter obtained in step 3) is coated with 120 g / L of catalyst to obtain a gasoline engine particulate filter.

8. The method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution according to claim 7, characterized in that: In the step 3), the plugging depth is 3 to 10 mm.

9. A method for preparing a gasoline engine particulate filter with low back pressure increase and narrow pore size distribution as claimed in any one of claims 1 to 8, wherein the gasoline engine particulate filter is prepared.

10. The gasoline engine particulate filter according to claim 9, characterized in that: The porosity of gasoline engine particulate filter is 53-63%.

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