Low-cost and high-performance cordierite honeycomb ceramic carrier and preparation method thereof

Abstract

The invention relates to the technical field of ship tail gas treatment, in particular to a low-cost and high-performance cordierite honeycomb ceramic carrier and a preparation method thereof. The cordierite honeycomb ceramic carrier is prepared from cordierite honeycomb ceramic carrier green body waste, a binder, an organic pore-forming agent, water and a lubricant. The green body waste of the cordierite honeycomb ceramic carrier is waste which is subjected to microwave treatment and is not subjected to high-temperature sintering; the organic pore-forming agent comprises one or more of expanded microspheres, expanded resin and potato starch. According to the method, the raw material cost can be reduced, the solid waste can be reasonably used, and the obtained honeycomb ceramic carrier has a good radial shrinkage effect; the method can be applied to ship tail gas treatment, so that the treated ship tail gas meets the emission standard.

Description

Technical Field

[0001] The invention relates to the technical field of ship exhaust treatment, and in particular to a low-cost, high-performance cordierite honeycomb ceramic carrier and a preparation method thereof. Background Art

[0002] With the continuous development of international trade, more and more goods are transported between countries. Ship transportation plays an important role in the entire transportation system due to its advantages such as large transportation volume, long-distance transportation and low cost. Most commercial ships on the market use diesel engines as energy. Diesel will produce a large amount of pollutants during the combustion process, such as particulate matter, CO, NOx, SO2, HC, etc. These pollutants are not only harmful to the environment, but also to people's physical and mental health. At present, the NOx in the exhaust gas is mainly treated by selective catalytic reduction SCR, which mainly reacts with NOx in the exhaust gas at a certain temperature by injecting ammonia or urea through the action of a catalyst to generate pollution-free N2 and water, thereby reducing the NOx content in the exhaust gas.

[0003] As regulations become increasingly stringent, countries have also strengthened their requirements for ship exhaust emissions. In order to achieve a higher conversion efficiency for exhaust gas, the honeycomb ceramic carrier is required to have a sufficiently large specific surface area to increase the catalyst loading, which requires the honeycomb ceramic carrier to have a sufficient median pore size and porosity. At the same time, the SCR ceramic honeycomb carrier used in ships is generally a 150*150*300-450mm skinned product, and there is no finishing process after sintering, so the product size is difficult to control. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a low-cost, high-performance cordierite honeycomb ceramic carrier and a preparation method thereof.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: The present invention provides a method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier, which is prepared by using cordierite honeycomb ceramic carrier green body waste, a binder, an organic pore-forming agent, water and a lubricant; The cordierite honeycomb ceramic carrier green body waste is waste that has been subjected to microwave treatment but not subjected to high-temperature sintering; the organic pore-forming agent includes one or more of expanded microspheres, expanded resin, and potato starch.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the organic pore-forming agent is potato starch, and the particle size D of the potato starch is 50 35-42μm.

[0008] Furthermore, in the cordierite honeycomb ceramic carrier green body waste, the mass percentage of each component is SiO2≥48%, Al2O3≥32%, MgO≥11%, and also includes acceptable impurities, and the total mass percentage of each component and impurities is 100% of the organic pore-forming agent.

[0009] Furthermore, the cordierite honeycomb ceramic carrier green body waste includes sintering expansion waste and sintering shrinkage waste, the sintering expansion waste accounts for 10% to 50% of the total mass of the cordierite honeycomb ceramic carrier green body waste, and the sintering shrinkage waste accounts for 50% to 90% of the total mass of the cordierite honeycomb ceramic carrier green body waste.

[0010] Furthermore, the sintering expansion waste is waste that expands in volume after high-temperature sintering, and the sintering shrinkage waste is waste that shrinks in volume after high-temperature sintering.

[0011] Further, the following steps are included: S1, crushing the sintering expansion waste and the sintering shrinkage waste respectively, sieving and mixing them to obtain a first material; S2, mixing the binder, the organic pore-forming agent and the first material to obtain a second material; S3, kneading the second material, and adding water and the lubricant to obtain a mud segment; S4, screening, extruding and microwave treating the mud segments to obtain a ceramic blank; S5, sintering the ceramic green body to obtain the low-cost, high-performance cordierite honeycomb ceramic carrier.

[0012] Furthermore, in step S2, based on the mass of the first material being 100%, the mass percentage of the binder is 3-6wt%, and the mass percentage of the organic pore-forming agent is 20-30wt%.

[0013] Furthermore, in step S3, based on the mass of the second material being 100%, the mass percentage of water is 25-30wt%, and the mass percentage of the lubricant is 2-4wt%.

[0014] Further, in step S5, during the sintering process, the temperature rise program is: The temperature range of the first heating stage is from room temperature to 500°C, and the heating rate is less than 30°C / h. The temperature range of the second heating stage is 500℃ to 1000℃, and the heating rate is less than 40℃ / h. The temperature range of the third heating stage is from 1000°C to the holding temperature, the heating rate is less than 70°C / h, and the holding time is 8 to 16 hours; Wherein, the normal temperature is 20°C-30°C, and the insulation temperature is 1370°C-1400°C.

[0015] The present invention also provides a low-cost, high-performance cordierite honeycomb ceramic carrier, which is prepared by the above method.

[0016] The beneficial effects of the present invention are: (1) The low-cost, high-performance cordierite honeycomb ceramic carrier preparation method of the present invention uses the cordierite honeycomb ceramic carrier green body waste as raw material, which can not only reduce the raw material cost, but also reasonably use the solid waste. At the same time, the waste is directly used as the raw material, and there is no need to mix the original raw material in terms of composition and particle size, which effectively improves the preparation efficiency; (2) The low-cost, high-performance cordierite honeycomb ceramic carrier preparation method of the present invention reasonably matches the sintering expansion waste and the sintering shrinkage waste, so that the obtained honeycomb ceramic carrier has a good radial shrinkage effect; (3) The low-cost, high-performance cordierite honeycomb ceramic carrier preparation method of the present invention uses an organic pore-forming agent with an expansion effect. By utilizing its dimensional expansion property at low temperatures, it can offset part of the dimensional shrinkage of the product during high-temperature sintering, thereby achieving low shrinkage or even zero shrinkage during high-temperature sintering; (4) The low-cost, high-performance cordierite honeycomb ceramic carrier of the present invention has both high-medium pore diameter and high porosity, which can effectively increase the coating amount of the catalyst; (5) The low-cost, high-performance cordierite honeycomb ceramic carrier of the present invention can be applied to ship exhaust treatment, so that the treated ship exhaust meets the emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The preparation method of the cordierite honeycomb ceramic carrier of the present invention is a SEM image of the wall surface of the cordierite honeycomb ceramic carrier of Example 3; Figure 2 This is a SEM image of the cross section of the cordierite honeycomb ceramic carrier wall of Example 3 according to the method for preparing the cordierite honeycomb ceramic carrier of the present invention. DETAILED DESCRIPTION

[0018] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0019] The low-cost, high-performance cordierite honeycomb ceramic carrier preparation method of the present invention adopts cordierite honeycomb ceramic carrier green body waste, binder, organic pore-forming agent, water and lubricant for preparation; wherein, the cordierite honeycomb ceramic carrier green body waste is waste that has been subjected to microwave treatment but not subjected to high-temperature sintering; wherein, the cordierite honeycomb ceramic carrier green body waste is waste that has been subjected to microwave treatment but not subjected to high-temperature sintering; the organic pore-forming agent includes one or more of expanded microspheres, expanded resin and potato starch.

[0020] The low-cost, high-performance preparation method of the cordierite honeycomb ceramic carrier of the present invention uses the green waste of the cordierite honeycomb ceramic carrier as raw material, which can not only reduce the raw material cost, but also reasonably use solid waste. At the same time, the green waste is directly used as the raw material, and there is no need to mix the components and particle size of the original raw material, which effectively improves the preparation efficiency; the reasonable combination of sintering expansion waste and sintering shrinkage waste can make the obtained honeycomb ceramic carrier have a good radial shrinkage effect. The pore former used in the method of the present invention is an expansion type pore former. These organic pore formers have an expansion effect. By utilizing their dimensional expansion properties at low temperatures, they can offset the partial dimensional shrinkage of the product during high-temperature sintering, thereby achieving low shrinkage or even zero shrinkage during high-temperature sintering. In this way, during sintering, the size of the product can be effectively controlled to prevent the product from being over-expanded, resulting in the product size being difficult to control. At the same time, the pore former of the present invention can also ensure that the performance indicators such as the porosity and median pore size of the product meet the requirements.

[0021] The reason why the preparation method of the present invention uses green waste as raw material is that the green waste has not yet synthesized the cordierite phase and is in the form of flaky powder. The raw material can also be oriented in a certain way to reduce the CTE of the product. In addition, the green waste is basically a flaky structure, which is more conducive to extrusion. If it is a cooked waste, cordierite has been synthesized, and the CTE of the product will increase. In addition, the cooked waste has a certain strength and needs to be crushed. The microscopic morphology of the raw material after crushing is irregular granular, which is not conducive to extrusion molding.

[0022] Preferably, the organic pore-forming agent is potato starch, and the particle size D of the potato starch is 50 35-42μm.

[0023] Preferably, the cordierite honeycomb ceramic carrier green body waste includes sintering expansion waste and sintering shrinkage waste, the sintering expansion waste accounts for 10% to 50% of the total mass of the cordierite honeycomb ceramic carrier green body waste, and the sintering shrinkage waste accounts for 50% to 90% of the total mass of the cordierite honeycomb ceramic carrier green body waste.

[0024] Preferably, the cordierite honeycomb ceramic carrier green waste used in the present invention is a waste of honeycomb ceramic carrier that meets the National VI Standard, and the mass percentage of each component is SiO2≥48%, Al2O3≥32%, MgO≥11%, and the remainder is acceptable impurities.

[0025] Preferably, sintering expansion waste specifically refers to waste material whose volume will expand during high-temperature sintering, and sintering shrinkage waste specifically refers to waste material whose volume will shrink during high-temperature sintering; sintering expansion waste and sintering shrinkage waste are waste materials that can be clearly obtained by technical personnel in this field.

[0026] Preferably, the binder is one or more selected from methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and polyvinyl alcohol (PVA).

[0027] Preferably, the lubricant is one or more of calcium stearate, white oil, base oil, glycerol, polyethylene glycol, synthetic fatty acid, and water-soluble polyamide.

[0028] The method for preparing the low-cost, high-performance cordierite honeycomb ceramic carrier of the present invention comprises the following steps: S1. Sintering expansion waste and sintering shrinkage waste are crushed and sieved respectively and then mixed to obtain a first material.

[0029] Preferably, the crushing time is 20-40 min and the sieve mesh number is 60 meshes.

[0030] S2. Mixing a binder, an organic pore-forming agent and the first material to obtain a second material.

[0031] Preferably, based on 100% of the mass of the first material, the mass percentage of the binder is 3-6wt%, and the mass percentage of the organic pore former is 20-30wt%.

[0032] S3, kneading the second material, and adding water and a lubricant to obtain a mud segment.

[0033] Preferably, based on 100% of the mass of the second material, the mass percentage of water is 25-30wt%, and the mass percentage of the lubricant is 2-4wt%.

[0034] S4, screening, extruding and microwave treating the mud segments to obtain a ceramic blank; S5. Sintering the ceramic green body to obtain a low-cost, high-performance cordierite honeycomb ceramic carrier.

[0035] Preferably, during the sintering process, the heating program is: The temperature range of the first heating stage is from room temperature to 500°C, and the heating rate is less than 30°C / h; The temperature range of the second heating stage is 500°C to 1000°C, and the heating rate is less than 40°C / h; The temperature range of the third heating stage is from 1000°C to the holding temperature, the heating rate is less than 70°C / h, and the holding time is 8 to 16 hours.

[0036] Among them, the normal temperature is 20℃-30℃, and the insulation temperature is 1370℃-1400℃.

[0037] In the above sintering process, the heating rate of the second heating stage can be lower than that of the first stage, but this will lead to waste of gas and high preparation cost. The heating rate of the third heating stage is similar.

[0038] Therefore, it is further preferred that the heating rate in the second heating stage is greater than 30°C / h and less than 40°C / h, and the heating rate in the third heating stage is greater than 40°C / h and less than 70°C / h.

[0039] The low-cost, high-performance cordierite honeycomb ceramic carrier of the present invention is prepared by the above method.

[0040] Preferably, the low-cost, high-performance cordierite honeycomb ceramic substrate of the present invention can be applied to ship exhaust treatment, so that the treated ship exhaust meets the emission standards.

[0041] The present invention is illustrated below by means of specific examples.

[0042] The sintering shrinkage waste and sintering expansion waste used in Examples 1 to 5 and Comparative Examples 1 to 2 are both green waste of honeycomb ceramics that meet the National VI standard, and the component compositions are the same, specifically: SiO2: 51.3% ± 2.5%, Al2O3: 34.9% ± 2.5%, MgO: 13.8% ± 2.0%, and the total mass percentage of each component is 100%.

[0043] The specific preparation process of each embodiment and comparative example is as follows: S1. The sintering expansion waste and the sintering shrinkage waste are crushed and sieved respectively and then mixed to obtain a first material. The crushing time is 30 minutes and the sieve mesh number is 60 meshes.

[0044] S2, mixing a binder, an organic pore-forming agent and the first material to obtain a second material.

[0045] S3, kneading the second material, and adding water and a lubricant to obtain a mud segment.

[0046] S4, screening, extruding and microwave treating the mud segments to obtain a ceramic blank; S5. Sintering the ceramic blank to obtain a low-cost, high-performance cordierite honeycomb ceramic carrier. During the sintering process, the heating program is: 25°C to 500°C, the heating rate is 25°C / h, 500°C to 1000°C, the heating rate is 35°C / h, 1000°C to 1400°C, the heating rate is 65°C / h, and the insulation time is 12 hours.

[0047] The specific compositions and parameters of each embodiment and comparative example are shown in Table 1, wherein the content of each component is calculated in wt%.

[0048] Table 1 The wall surface SEM image and wall cross-section SEM image of the cordierite honeycomb ceramic carrier of Example 3 are shown as follows: Figure 1 and 2 shown.

[0049] according to Figure 1~2 As can be seen from Table 1, by comparing Examples 1-3 and Examples 4-5, it can be found that by reasonably matching the ratio of National VI sintering shrinkage green waste, National VI sintering expansion green waste and pore-forming agent, the product size shrinkage can be ensured to be small and the physical size of the product can be guaranteed.

[0050] By comparing Example 2 with Examples 4-5, it can be found that the more potato starch is added, the greater the size expansion of the product, indicating that its expansion effect plays a certain role in the size control of the product, and potato starch has a strong pore-forming ability. As its addition amount increases, the median pore diameter and porosity increase significantly. Although the median pore diameter and porosity of Example 5 are higher, which is more conducive to increasing the coating amount of the catalyst, its size expansion is too large, which is not conducive to size control.

[0051] It can be seen from Comparative Example 1 that although low-shrinkage products can be obtained by combining National VI sintering shrinkage green waste and National VI sintering expansion green waste, the median pore size and porosity are relatively low, and the catalyst coating amount cannot be increased.

[0052] It can be seen from Comparative Example 2 that although the performance of the product can meet the requirements of use when using shrinkable fruit shell as a pore-forming agent, its radial shrinkage is large because its low-temperature decomposition process is a shrinkage process, which is not conducive to controlling the size of the product.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier, characterized in that: The method is prepared by using cordierite honeycomb ceramic carrier green body waste, a binder, an organic pore-forming agent, water and a lubricant; Among them, the cordierite honeycomb ceramic carrier green waste is waste that has been subjected to microwave treatment but not subjected to high-temperature sintering, and the cordierite honeycomb ceramic carrier green waste includes sintering expansion waste and sintering shrinkage waste; the organic pore-forming agent includes one or more of expanded microspheres, expanded resin, and potato starch.

2. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 1, characterized in that: The organic pore-forming agent is potato starch, and the particle size of the potato starch is 50 35-42μm.

3. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 2, characterized in that: The mass percentage of each component in the cordierite honeycomb ceramic carrier green body waste is SiO2≥48%, Al2O3≥32%, MgO≥11%, and also includes acceptable impurities, and the total mass percentage of each component and impurities is 100%.

4. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 3, characterized in that: The sintering expansion waste accounts for 10% to 50% of the total mass of the cordierite honeycomb ceramic carrier green waste, and the sintering shrinkage waste accounts for 50% to 90% of the total mass of the cordierite honeycomb ceramic carrier green waste.

5. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 4, characterized in that: The sintering expansion waste is waste whose volume expands after high-temperature sintering, and the sintering shrinkage waste is waste whose volume shrinks after high-temperature sintering.

6. A method for preparing a low-cost, high-performance cordierite honeycomb ceramic substrate according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, crushing the sintering expansion waste and the sintering shrinkage waste respectively, sieving and mixing them to obtain a first material; S2, mixing the binder, the organic pore-forming agent and the first material to obtain a second material; S3, kneading the second material, and adding water and the lubricant to obtain a mud segment; S4, screening, extruding and microwave treating the mud segments to obtain a ceramic blank; S5, sintering the ceramic green body to obtain the low-cost, high-performance cordierite honeycomb ceramic carrier.

7. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 6, characterized in that: In step S2, based on the mass of the first material being 100%, the mass percentage of the binder is 3-6wt%, and the mass percentage of the organic pore-forming agent is 20-30wt%.

8. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 6, characterized in that: In step S3, based on the mass of the second material being 100%, the mass percentage of water is 25-30wt%, and the mass percentage of the lubricant is 2-4wt%.

9. The method for preparing a low-cost, high-performance cordierite honeycomb ceramic carrier according to claim 6, characterized in that: In step S5, during the sintering process, the temperature rise program is: The temperature range of the first heating stage is from room temperature to 500°C, and the heating rate is less than 30°C / h. The temperature range of the second heating stage is 500℃ to 1000℃, and the heating rate is less than 40℃ / h. The temperature range of the third heating stage is from 1000°C to the holding temperature, the heating rate is less than 70°C / h, and the holding time is 8 to 16 hours; Wherein, the normal temperature is 20°C-30°C, and the insulation temperature is 1370°C-1400°C.

10. A low-cost, high-performance cordierite honeycomb ceramic carrier, characterized in that: The method is prepared by any one of claims 1 to 9.

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