WO2020228652A1 - Afi-cha混晶分子筛及以其为载体的nh 3-scr催化剂以及它们的制备方法 - Google Patents

Afi-cha混晶分子筛及以其为载体的nh 3-scr催化剂以及它们的制备方法 Download PDF

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WO2020228652A1
WO2020228652A1 PCT/CN2020/089513 CN2020089513W WO2020228652A1 WO 2020228652 A1 WO2020228652 A1 WO 2020228652A1 CN 2020089513 W CN2020089513 W CN 2020089513W WO 2020228652 A1 WO2020228652 A1 WO 2020228652A1
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afi
cha
molecular sieve
mixed crystal
catalyst
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French (fr)
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徐海迪
林青瑾
陈耀强
王云
冯锡
王健礼
赵明
焦毅
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Sichuan University
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Sichuan University
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Definitions

  • the invention belongs to the technical field of NH 3 -SCR, and specifically relates to an NH 3 -SCR catalyst.
  • Nitrogen oxides (NO x ) emitted by diesel vehicle exhaust is one of the main air pollutants in cities, which can cause acid rain, haze, and photochemical smog. It has become an important cause of cancer and other diseases and is a serious threat to human health.
  • Selective Catalytic Reduction (SCR) was first proposed by Engelhard, and was first used for stationary source denitration by the Kudamatsu power plant in Japan. It uses reducing agent to reduce NO x in exhaust gas to non-toxic N 2 and H 2 O. The choice of reducing agent is very wide. It can be HCs, some alcohols or ethers and other oxygen-containing organics, ammonia or H 2 and so on.
  • HCs as a reducing agent to reduce NO x does not require additional reducing agents and corresponding equipment.
  • HCs are directly derived from fuel oil, so there is a certain cost advantage.
  • NO x conversion efficiency and temperature window of HC-SCR have not been able to obtain satisfactory results, and serious sulfur poisoning and carbon deposition effects may occur, which directly affects the program’s performance on real vehicles. Promotion.
  • the low-temperature NO x conversion effect of H 2 -SCR is better than that of HC-SCR, and the conversion peak is about 150°C. It will not generate carbon, sulfate or nitrate at low temperatures.
  • the NO x conversion rate, temperature window and N 2 selectivity of NH 3 -SCR technology have obvious advantages. This technology was first used for fixed source denitrification, and was later transplanted to mobile sources due to the introduction of mobile source regulations. After years of improvement and development, NH 3 -SCR technology has become a relatively mature and reliable technology, and has been widely used in diesel vehicle exhaust treatment systems. As the core of the NH 3 -SCR, research and development NH 3 -SCR catalyst has become a research focus. However, at present, the NH 3 -SCR catalyst based on V 2 O 5 /WO x -TiO 2 in China has poor low temperature activity, high volatility of vanadium oxide at high temperature, low N 2 selectivity, and low N 2 selectivity. 2.
  • the common types of molecular sieves used in the NH 3 -SCR system mainly include MFI (ZSM-5), BEA (beta) and CHA (SAPO-34 and SSZ-13).
  • transition metal (Fe and Cu) supported molecular sieve catalyst has high activity in the NH 3 -SCR reaction, excellent N 2 selectivity, a wider temperature window, better high-temperature hydrothermal stability, and its abandonment
  • the non-toxicity of the environment has received extensive attention.
  • the NH 3 -SCR catalyst in diesel vehicles is located downstream of the DPF, it is easily affected by its periodic high-temperature regeneration.
  • the temperature during regeneration can be instantly increased to 600°C, or even 800°C, plus the combustion characteristics of diesel engines (Lean burn) also determines that there is always about 10vol.% of water vapor in the exhaust gas, so the high-temperature hydrothermal stability requirements for the NH 3 -SCR catalyst are put forward.
  • the Cu-based catalysts supported by the small-pore molecular sieve (SSZ-13 and SAPO-34) with CHA structure have received extensive attention from researchers in recent years. A large number of experiments have shown that this type of catalyst has relatively excellent activity, and can achieve complete conversion of NO x at a lower temperature and a wider temperature window. But for the Cu/SSZ-13 catalyst, its high temperature hydrothermal aging activity is worse than that of Cu/SAPO-34, and its application in industrial production is further restricted due to the use of expensive template agents.
  • the Cu/SAPO-34 catalyst has become one of the most effective NH 3 -SCR catalysts because of its relatively excellent hydrothermal stability. However, due to the working conditions of diesel vehicles and national standards, the exhaust emissions of diesel vehicles Requirements, its high-temperature hydrothermal stability performance still needs to be further improved.
  • the purpose of the present invention is to provide an AFI-CHA mixed crystal molecular sieve and a preparation method thereof in view of the shortcomings of the prior art, and further improve the catalytic activity and high-temperature hydrothermal stability of the Cu-based molecular sieve NH3-SCR catalyst.
  • SAPO-34 is a typical CHA type small pore molecular sieve, and its skeleton contains an eight-membered ring-shaped ellipsoidal cage structure and a hexagonal structure.
  • SAPO series molecular sieves are very sensitive to the synthesis conditions: the composition of the gel, the crystallization temperature and the crystallization time will all affect the distribution of Si into the molecular sieve.
  • SAPO-5 molecular sieve is SAPO-n series molecular sieve with AFI type structure, which contains two six-membered rings and two four-membered rings with one-dimensional pore structure of twelve-membered ring.
  • SAPO-5 which is also the SAPO series
  • SAPO-5 molecular sieve skeleton has a negative charge, so it has the ability of ion exchange.
  • the structure of AFI molecular sieve is stable. According to the synthesis characteristics of SAPO-n series molecular sieve, the crystallization temperature conditions can be changed to obtain mixed crystal grains of AFI and CHA, thereby improving the high-temperature hydrothermal stability of SAPO-34 molecular sieve.
  • the invention provides an AFI-CHA mixed crystal molecular sieve, which is composed of an AFI-type SAPO-5 molecular sieve and a CHA-type SAPO-34 molecular sieve, and the crystal grains are mixed crystal grains of AFI and CHA.
  • the topological structure code of the framework structure of the new AFI-CHA molecular sieve material is the AFI and CHA molecular sieve proposed by the International Zeolite Federation (IZA).
  • the present invention provides a Cu/AFI-CHA supported molecular sieve catalyst based on the above AFI-CHA mixed crystal molecular sieve, which is characterized in that Cu is supported on the AFI-CHA mixed crystal molecular sieve.
  • the present invention provides a monolithic catalyst, comprising a substrate and Cu/AFI-CHA supported catalyst powder, wherein the Cu/AFI-CHA supported catalyst powder is supported on a cordierite substrate.
  • the present invention provides a method for preparing the above-mentioned AFI-CHA mixed crystal molecular sieve.
  • the molar ratio of the feed is based on the molar ratio of aluminum: phosphorus: silicon: structure directing agent (template): water in the molecular sieve. (0.06 ⁇ 0.10): (0.06 ⁇ 0.10): (0.040 ⁇ 0.050): (0.12 ⁇ 0.35): (0.5 ⁇ 6) for feeding;
  • the molar ratio of the mixed solution according to Al 2 O 3 : P 2 O 5 : SiO 2 : structure directing agent: H 2 O is (0.06 ⁇ 0.10): (0.06 ⁇ 0.10): (0.040 ⁇ 0.050 ): (0.01 ⁇ 0.40): (0.5 ⁇ 6) for feeding.
  • the method includes the following steps:
  • pseudo-boehmite is 8-15 parts by mass
  • phosphoric acid is 13-23 parts by mass
  • Si source is 5-8 parts by mass
  • structure directing agent is 1-41 parts.
  • step (1) when preparing the P/Al oxide mixed gel, stirring for 1-24 hours, and aging at room temperature for 1-24 hours.
  • the heating rate of the temperature in step (2) is 3 to 6° C. ⁇ min -1 .
  • the structure directing agent is triethylamine TEA.
  • the molar ratio of aluminum: phosphorus: silicon: structure directing agent (template): water is (0.06 ⁇ 0.10): (0.06 ⁇ 0.10): (0.040 ⁇ 0.050): (0.01 ⁇ 0.4): (0.5 ⁇ 6) Feeding; three mixed crystal molecular sieve powders of SAPO-34, SAPO-5 and AFI-CHA can be prepared by changing the content of template agent.
  • the ratio of structure directing agent (templating agent) when preparing SAPO ⁇ 34 is 0.35 ⁇ 0.40
  • the ratio of structure directing agent (templating agent) when preparing SAPO ⁇ 5 is 0.01 ⁇ 0.12
  • the structure directing agent when preparing AFI-CHA molecular sieve powder The ratio of (template agent) is 0.12 ⁇ 0.35.
  • the heating rate during the hydrothermal reaction can also be adjusted to synthesize different types of molecular sieve powder: when the heating rate is faster (3 ⁇ 6°C ⁇ min ⁇ 1 ), mixed crystal molecular sieve is easy to form, while the heating rate is slower (1 ⁇ 3°C ⁇ min ⁇ 1 ) easy to produce SAPO-34 and SAPO-5 molecular sieve powder.
  • the present invention provides a method for preparing a Cu-based molecular sieve catalyst using the above-mentioned mixed crystal molecular sieve as a carrier.
  • the copper salt compound is used as the precursor, and the AFI-CHA mixed crystal molecular sieve and the copper salt solution are mixed and stirred until the mixture is viscous.
  • the copper is used in the molecular sieve. Then, the mixture is allowed to stand, dried in a water bath, and calcined in a muffle furnace at 300-600°C for 3-6 hours to obtain Cu/AFI-CHA supported catalyst powder.
  • the copper salt is selected from Cu(NO 3 ) 2 , Cu(Ac) 2 , Cu(COOH) 2 ).
  • the standing time is 1 to 15 hours
  • the temperature of the water bath is 50 to 80° C.
  • the drying time is 1 to 7 hours.
  • the present invention also provides a method for preparing the above-mentioned Cu/AFI ⁇ CHA supported catalyst into a monolithic catalyst: the Cu/AFI ⁇ CHA supported catalyst powder is prepared into a slurry and coated on the cordierite substrate, and the catalyst powder is on the cordierite The upper load is 120 ⁇ 130g/L; then the coated substrate is dried at 70 ⁇ 150°C, and then baked at 300 ⁇ 600°C for 3 ⁇ 6h.
  • cordierite matrix is selected from Corning Corporation, USA, 400 mesh, 2.5 cm 3 .
  • the present invention has the following beneficial effects:
  • Figure 1 shows the XRD patterns of Cu/SAPO-34, Cu/SAPO-5 and Cu/AFI-CHA catalysts
  • Figure 2 shows the SEM images of Cu/SAPO-34, Cu/SAPO-5 and Cu/AFI-CHA catalysts (A-Comparative Example 1, B-Example 1, C-Example 2, D-Example 3, E- Comparative example 2);
  • Figure 3 shows the XRD patterns of Cu/SAPO-34 and Cu/AFI-CHA high temperature hydrothermal aging catalysts
  • Figure 4 is the SEM image of Cu/SAPO-34 and Cu/AFI-CHA fresh and high temperature hydrothermal aging catalysts (A-Comparative Example 3, B-Example 5, C-Comparative Example 4, D-Example 6);
  • Figure 6 SEM images of Cu/SAPO-34 and Cu/AFI-CHA fresh and high temperature hydrothermal aging catalysts.
  • 15g pseudo-boehmite, 17g phosphoric acid and 48g water are mixed uniformly, stirred for 12 hours, and aged at room temperature for 24 hours to prepare a P/Al oxide hybrid gel.
  • 8g of 44nm Si sol provided by Shanghai Nalco Company was added as Si source, 35g of structure directing agent TEAOH was added, and the remaining 24g of distilled water was added and mixed uniformly and stirred for 12h, and left standing at room temperature for 12h to obtain a mixed solution.
  • the mixed solution was transferred to a hydrothermal kettle, and placed in an oven at a heating rate of 3°C ⁇ min -1 to 160°C for 20 hours, and then heated to 200°C for 30 hours. After natural cooling to room temperature, centrifuge and wash 5 times.
  • the structure-directing agent was calcined at 600°C for 5 hours to obtain SAPO-34 molecular sieve powder.
  • 8g pseudo-boehmite, 13g phosphoric acid and 12g water are mixed uniformly, stirred for 12h, and aged at room temperature for 12h to prepare a P/Al oxide hybrid gel.
  • 6g of 44nm Si sol provided by Shanghai Nalco Company was added as the Si source, 10g of structure directing agent TEA was added, and the remaining 8g of distilled water was added and mixed uniformly and stirred for 1h, and allowed to stand for 24h at room temperature to obtain a mixed solution.
  • the mixed solution was transferred to a hydrothermal kettle and placed in an oven at a heating rate of 1°C ⁇ min ⁇ 1 to 140°C for 10 hours, and then heated to 200°C for 20 hours. After natural cooling to room temperature, centrifuge and wash twice. Finally, it was calcined at 500°C for 8 hours to remove the structure directing agent to obtain SAPO-5 molecular sieve powder.
  • Example 1-4 and Comparative Example 1-2 were prepared into a supported catalyst according to the following method, and further made into a monolithic catalyst:
  • Use copper salt compounds such as: Cu(NO 3 ) 2 , Cu(Ac) 2 and Cu(COOH) 2 ) as precursors to prepare Cu-supported AFI/CHA mixed crystal molecular sieve catalyst, and dissolve the copper salt compounds in deionized water
  • prepare a certain concentration of metal salt solution respectively weigh 10g prepared SAPO-34, SAPO-5 and AFI-CHA mixed crystal molecular sieves, pour into the copper salt solution and stir for 30 minutes, continue stirring until the mixture is viscous to ensure copper The species are uniformly dispersed in the molecular sieve.
  • the mixture was allowed to stand for 10 hours and then transferred to a water bath at 80°C for drying for 6 hours, and then calcined in a muffle furnace at 500°C for 4 hours to obtain Cu/CHA, Cu/AFI and Cu/AFI-CHA supported catalyst powders.
  • the Cu/SAPO-34, Cu/SAPO-5 and Cu/AFI-CHA molecular sieve-based catalysts were respectively coated on the cordierite carrier (Corning, USA, 400 mesh, 2.5cm 3 ) by the following coating technology to make a monolith
  • the specific method of the catalyst is as follows:
  • the coated substrate is gradually heated from room temperature to 100°C for drying, and then calcined at 500°C4 to obtain monolithic Cu/SAPO-34, Cu/SAPO-5 and Cu/AFI-CHA molecular sieve based catalysts.
  • the copper loading is the same as the loading of the catalyst on the monolithic catalyst.
  • the NH 3 -SCR conversion efficiency test was performed in a self-assembled multi-channel fixed continuous flow micro-reactor in the laboratory.
  • the simulated diesel vehicle exhaust composition and experimental conditions are shown in Table 1.
  • the monolithic catalyst was pretreated at 550°C in the reaction gas (simulated diesel vehicle exhaust). Then, the method of cooling test is adopted, and the activity test is performed after each temperature point is equilibrated. The unconverted NO, NO 2 and N 2 O were tested with a Fourier infrared gas analyzer (Thermol Fisher Scientific).
  • the Cu/AFI-CHA monolithic catalyst prepared in Example 5 was subjected to an activity test after hydrothermal aging at 800°C for 12 hours in flowing air containing 10vol.% H 2 O.
  • the Cu/CHA monolithic catalyst prepared according to Comparative Example 3 will be subjected to activity test after hydrothermal aging at 800°C for different time (24-72h) in flowing air containing 10vol.% H 2 O, reaction gas composition and test method Same as Table 1 and Catalyst Performance Test 1.
  • Figure 6 shows the NH 3 -SCR activity results of the fresh and high-temperature hydrothermal aging catalysts of the molecular sieve of Comparative Example 3 and Example 5. It can be seen from the figure that in the temperature range of 200-450°C, the NO x conversion rates of the two fresh catalysts are very close, and the highest conversion rate is about 90%. In the low temperature section (150-200° C.), the activity of Example 5 is better than that of Comparative Example 3. This may be due to the larger proportion of mesopores in the mixed crystal AFI-CHA, which is beneficial to the diffusion of reaction gas in the low temperature section. In the high temperature section (450-550°C), the catalyst of Comparative Example 3 has better activity.
  • Example 6 After high-temperature hydrothermal aging, the activity retention of Example 6 is better than that of the sample of Comparative Example 4.
  • the maximum NO x conversion rate of the aged catalyst of Example 6 hardly decreases, while the maximum NO x conversion rate of the aged catalyst of Comparative Example 4 decreases. 8%, indicating that the backup catalyst prepared by the method of the present invention has better low-temperature activity and hydrothermal stability.

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Abstract

一种AFI-CHA混晶分子筛及以其为载体的NH 3-SCR催化剂以及它们的制备方法。所述AFI-CHA混晶分子筛，由AFI型的SAPO-5分子筛和CHA型的SAPO-34分子筛组成，其晶粒为AFI和CHA的混合晶粒。该混晶分子筛采用水热合成法合成，在制备过程中可通过改变结构导向剂，升温速率以及焙烧温度等得到。在此混晶分子筛的基础上负载铜制备成铜基NH 3-SCR催化剂和相应的整体式催化剂，混晶分子筛显著提高了催化剂的催化活性和水热稳定性。

Description

AFI-CHA混晶分子筛及以其为载体的NH 3-SCR催化剂以及它们的制备方法 技术领域
本发明属于NH 3-SCR技术领域，具体涉及一种NH 3-SCR催化剂。
背景技术
柴油车尾气排放的氮氧化物(NO x)是城市主要大气污染物之一，会造成酸雨和雾霾以及光化学烟雾等问题，已经成为诱发癌症等疾病的重要原因，严重威胁着人类的健康。选择性催化还原技术(SCR)是由Engelhard公司首先提出，由日本Kudamatsu发电厂首先用于固定源的脱硝。它是利用还原剂将尾气中的NO x还原为无毒的N 2和H 2O。还原剂的选择非常广泛，既可以是HCs，也可以是某些醇类或者醚类等含氧有机物以及氨气或者H 2等。以HCs作为还原剂来还原NO x不需要额外添加还原剂和相应的设备，HCs直接来源于燃油，因此在成本上有一定的优势。然而经过多年的研究，HC-SCR的NO x转化效率以及温度窗口等问题一直无法得到满意的效果，而且还有可能发生严重的硫中毒和积碳效应，直接影响了该方案在实车上的推广。H 2-SCR的低温NO x转化效果比HC-SCR要理想，转化顶峰在150℃左右。它在低温下不会有积碳、硫酸盐或者硝酸盐等生成。但是，该技术对H 2的消耗量过大(H 2/NO＝2)，而且N 2O选择性也比较高，加上该技术尚处于起步阶段，目前对其认识还远远不够，因此要想商业应用，其可行性和商业化的时间都还不确定。相对于以上两种方案，NH 3-SCR(NH 3选择性催化还原)能够有效地净化NO x，已经成为治理柴油车尾气污染的最有效的技术之一。
NH 3-SCR技术的NO x转化率和温度窗口以及N 2选择性都有明显的优势。该技术最先用于固定源脱硝，后因移动源法规的出台又将其移植到了移动源上。经过多年的改进和发展，NH 3-SCR技术已经成为了比较成熟可靠的技术，并且已经广泛应用于柴油车尾气处理系统。作为NH 3-SCR的核心部分，NH 3-SCR催化剂的研究和开发也成为了研究热点。但是目前我国以V 2O 5/WO x-TiO 2为主的NH 3-SCR催化剂存在有较差的低温活性、高温下钒氧化物的易挥发性、较低的N 2选择性以及对SO 2的强氧化性的缺点，这限制了其进一步的发展。自从1991 年具有大孔的ZSM-5分子筛用于NH 3-SCR领域以来，分子筛就因其具有环境友好、大比表面积和孔道复杂有序等特点，有利于金属物种在其表面和孔道内的分散，也有利于气体分子在孔道内的扩散，现已逐步成为NH 3-SCR催化剂的主流材料之一。而用于NH 3-SCR体系的常见分子筛类型主要包括MFI(ZSM-5)、BEA(beta)和CHA(SAPO-34和SSZ-13)等。而由于过渡金属(Fe和Cu)负载的分子筛催化剂在NH 3-SCR反应中具有高活性、优异的N 2选择性、较宽的温度窗口、较好的高温水热稳定性以及其废弃后对环境的无毒性，受到了广泛的关注。
此外，由于柴油车中NH 3-SCR催化剂位于DPF的下游，容易受到其周期性高温再生的影响，其再生时温度可以瞬间提高到600℃，甚至可能达到800℃，再加上柴油机的燃烧特点(稀燃)又决定了尾气中始终存在着10vol.％左右的水汽，因此对于NH 3-SCR催化剂又提出了高温水热稳定性的要求。
在所有的分子筛基催化剂中，又尤以具有CHA结构的小孔分子筛(SSZ-13和SAPO-34)负载的Cu基催化剂近年来受到研究学者的广泛关注。大量实验表明该类型催化剂具有较为优异的活性，并且能够在较低温度和较宽的温度窗口实现NO x的完全转化。但对于Cu/SSZ-13催化剂而言，其高温水热老化活性差于Cu/SAPO-34，而且还因需使用昂贵的模板剂而进一步限制了其在工业生产上的应用。而Cu/SAPO-34催化剂虽然因其有着相对较为优异的水热稳定性，已成为了最有效的NH 3-SCR催化剂之一，但由于柴油车工作条件要求和国家标准对柴油车尾气排放的要求，其高温水热稳定性能仍然有待进一步提升。
发明内容
本发明的目的在于针对现有技术的不足，提供一种AFI-CHA混晶分子筛及其制备方法，进一步提高Cu基分子筛NH3-SCR催化剂的催化活性和高温水热稳定性。
SAPO-34作为一种典型的CHA型小孔分子筛，骨架中含有八元环形的椭球形状的笼结构和六方体结构。SAPO系列分子筛对于合成的条件十分敏感：凝胶的组成、晶化温度和晶化时间都会对Si进入分子筛的分布产生影响，在SAPO-34的合成过程中，因为合成条件的改变，产品中往往伴随有SAPO-5。SAPO-5分子筛是具有AFI型结构的SAPO-n系列分子筛，其中含有二个六元环和二个四元环构成的十二元环一维孔道结构，在异构化、催化裂解、羰基化和羟基化等反应 中表现出了良好的催化效果。而同样是SAPO系列的SAPO-5在NH 3-SCR领域鲜有相关报道。在Si取代AlPO-5骨架原子后，SAPO-5分子筛骨架带有负电荷，因此具有离子交换的能力。而且AFI分子筛结构稳定，根据SAPO-n系列分子筛的合成特性，可以变化晶化温度条件得到AFI和CHA的混合晶粒，进而提高SAPO-34分子筛的高温水热稳定性。
本发明提供一种AFI-CHA混晶分子筛，由AFI型的SAPO-5分子筛和CHA型的SAPO-34分子筛组成，其晶粒为AFI和CHA的混合晶粒。
新型AFI-CHA分子筛材料骨架结构拓扑学结构代码为国际沸石联合会(IZA)提出AFI和CHA分子筛。
本发明提供一种基于上述AFI-CHA混晶分子筛的Cu/AFI-CHA负载型分子筛催化剂，其特征在于Cu负载在AFI-CHA混晶分子筛上。
本发明提供一种整体式催化剂，包括基体和Cu/AFI-CHA负载型催化剂粉末，其中Cu/AFI-CHA负载型催化剂粉负载在堇青石基体上。
本发明提供上述AFI-CHA混晶分子筛的制备方法，通过水热合成法合成合成过程中，投料摩尔比按照分子筛中，铝：磷：硅：结构导向剂(模板剂)：水的摩尔比为(0.06～0.10)：(0.06～0.10)：(0.040～0.050)：(0.12～0.35)：(0.5～6)进行投料；
也即，合成过程中，混合溶液按照Al 2O 3:P 2O 5:SiO 2:结构导向剂:H 2O的摩尔比为(0.06～0.10)：(0.06～0.10)：(0.040～0.050)：(0.01～0.40)：(0.5～6)进行投料。
进一步地，所述方法包括以下步骤：
(1)将拟薄水铝石、磷酸和总用水量中的一部分水混合均匀，搅拌并常温老化制备成P/Al氧化物混合凝胶，再向混合凝胶中添加Si源、结构导向剂和剩余的水，常温静置老化得到混合溶液；
(2)将混合溶液在120～160℃保温2～20h，再加热到190～210℃保温5～30h，自然冷却到室温后分离出固体，再在500～600℃焙烧5～8h烧除结构导向剂得到AFI～CHA混晶分子筛粉末。
进一步地，拟薄水铝石为8～15质量份，磷酸13～23质量份，Si源5～8质量份，结构导向剂1-41份。
进一步地，步骤(1)制备P/Al氧化物混合凝胶时搅拌1～24h，常温老化1～24h。
进一步地，步骤(2)所述温度的升温速率为3～6℃·min ～1。
进一步地，所述结构导向剂为三乙胺TEA。
在制备过程中可通过改变结构导向剂含量来合成一系列所需分子筛粉末：
按照分子筛中，铝：磷：硅：结构导向剂(模板剂)：水的摩尔比为(0.06～0.10)：(0.06～0.10)：(0.040～0.050)：(0.01～0.4)：(0.5～6)进行投料；可通过改变模板剂含量制备出SAPO-34，SAPO-5和AFI-CHA三种混晶分子筛粉末。制备SAPO～34时的结构导向剂(模板剂)比例为0.35～0.40，制备SAPO～5时的结构导向剂(模板剂)比例为0.01～0.12，而制备AFI-CHA分子筛粉末时的结构导向剂(模板剂)比例为0.12～0.35。也可调节水热反应时的升温速率来合成不同类型的分子筛粉末：升温速率较快(3～6℃·min ～1)时易生成混晶分子筛，而升温速率较慢(1～3℃·min ～1)时易生成SAPO-34和SAPO-5分子筛粉末。
本发明提供以上述混晶分子筛作为载体制备Cu基分子筛催化剂的方法，用铜盐化合物为前驱体，将AFI-CHA混晶分子筛与铜盐溶液混合搅拌至混合物呈现粘稠状，使用铜在分子筛中均匀分散；然后将混合物静置、水浴干燥后，在马弗炉中300～600℃焙烧3～6h，得Cu/AFI～CHA负载型催化剂粉末。
进一步地，所述铜盐选自Cu(NO 3) 2、Cu(Ac) 2、Cu(COOH) 2)。
进一步地，静置时间为1～15h，水浴干燥水浴温度为50～80℃，干燥时间为1～7h。
本发明还提供将上述Cu/AFI～CHA负载型催化剂制备成整体式催化剂的方法：将Cu/AFI～CHA负载型催化剂粉末配成浆料涂覆在堇青石基体上上，催化剂粉末在堇青石上的上载量为120～130g/L；然后将涂覆好的基体于70～150℃干燥，再在300～600℃下焙烧3～6h。
进一步地，所述堇青石基体选自美国Corning公司，400目，2.5cm 3。
与现有技术相比，本发明具有以下有益效果：
通过合成新型AFI-HA结构的混晶分子筛提高了Cu-CHA催化剂的NH3～SCR活性，并且更加稳定的结构促使其拥有比Cu分别负载于纯载体CHA和AFI分子筛更好的水热稳定性(见实施例和对比例)。
附图说明
图1为Cu/SAPO-34，Cu/SAPO-5和Cu/AFI-CHA催化剂XRD图；
图2为Cu/SAPO-34，Cu/SAPO-5和Cu/AFI-CHA催化剂SEM图(A-对比例1，B-实施例1，C-实施例2，D-实施例3，E-对比例2)；
图3为Cu/SAPO-34和Cu/AFI-CHA高温水热老化催化剂XRD图；
图4为Cu/SAPO-34和Cu/AFI-CHA新鲜及高温水热老化催化剂SEM图(A-对比例3，B-实施例5，C-对比例4，D-实施例6)；
图5 Cu/SAPO-34，Cu/SAPO-5和Cu/AFI-CHA催化剂NH 3-SCR活性图；
图6 Cu/SAPO-34和Cu/AFI-CHA新鲜及高温水热老化催化剂SEM图。
具体实施方式
下面结合具体实施方式对本发明做进一步说明。下面通过具体实施方式对本发明所述方法做进一步说明。以下实施方式仅作为本发明的一个实施案例，而不是全部的实施例。基于本实用新型中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本实用新型保护的范围。
实施例1
将15g拟薄水铝石、23g磷酸和72g的水混合均匀，搅拌12h，常温老化12h，制备成P/Al氧化物混合凝胶。加入6g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入20g结构导向剂TEA，并加入剩余的36g蒸馏水混合均匀并搅拌24h，常温静置老化12h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以5°·min ～1的升温速率升温至160℃保持10h，再加热到200℃反应20h。自然冷却到室温后离心洗涤4次。最后在550℃焙烧6h烧除结构导向剂得到SAPO-34、SAPO-5混合的AFI-CHA分子筛粉末，根据XRD中SAPO-5和SAPO-34的衍射主峰强度计算SAPO-5/SAPO-34为3.16。
实施例2
将15g拟薄水铝石、23g磷酸和72g的水混合均匀，搅拌12h，常温老化12h，制备成P/Al氧化物混合凝胶。加入6g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入35g结构导向剂TEA，并加入剩余的36g蒸馏水混合均匀并搅拌24h，常温静置老化12h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以4°·min ～1的升温速率升温至160℃保持10h，再加热到200℃反应20h。自然冷却到室温后离心洗涤4次。最后在550℃焙烧6h烧除结 构导向剂得到AFI～CHA分子筛粉末。
实施例3
将15g拟薄水铝石、23g磷酸和54g的水混合均匀，搅拌12h，常温老化12h，制备成P/Al氧化物混合凝胶。加入6g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入20g结构导向剂TEA，并加入剩余的54g蒸馏水混合均匀并搅拌24h，常温静置老化12h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以6℃·min ～1的升温速率升温至160℃保持10h,再加热到200℃反应20h。自然冷却到室温后离心洗涤4次。最后在550℃焙烧6h烧除结构导向剂得到AFI～CHA分子筛粉末。
实施例4
将15g拟薄水铝石、23g磷酸和72g的水混合均匀，搅拌12h，常温老化12h，制备成P/Al氧化物混合凝胶。加入6g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入12g结构导向剂TEA，并加入剩余的36g蒸馏水混合均匀并搅拌24h，常温静置老化12h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以3℃·min ～1的升温速率升温至160℃保持10h，再加热到200℃反应20h。自然冷却到室温后离心洗涤4次。最后在550℃焙烧6h烧除结构导向剂得到AFI-CHA分子筛粉末。
对比例1
将15g拟薄水铝石、17g磷酸和48g的水混合均匀，搅拌12h，常温老化24h，制备成P/Al氧化物混合凝胶。加入8g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入35g结构导向剂TEAOH，并加入剩余的24g蒸馏水混合均匀并搅拌12h，常温静置老化12h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以3℃·min ～1的升温速率升温至160℃保持20h,再加热到200℃反应30h。自然冷却到室温后离心洗涤5次。最后在600℃焙烧5h烧除结构导向剂得到SAPO-34分子筛粉末。
对比例2
将8g拟薄水铝石、13g磷酸和12g的水混合均匀，搅拌12h，常温老化12h，制备成P/Al氧化物混合凝胶。加入6g上海纳尔科公司提供的44nm大小Si溶胶作为Si源，加入10g结构导向剂TEA，并加入剩余的8g蒸馏水混合均 匀并搅拌1h，常温静置老化24h得到混合溶液。将混合溶液转移到水热釜中，置于烘箱中以1℃·min ～1的升温速率升温至140℃保持10h,再加热到200℃反应20h。自然冷却到室温后离心洗涤2次。最后在500℃焙烧8h烧除结构导向剂得到SAPO-5分子筛粉末。
按照以下方法将实施例1-4和对比例1-2制备的分子筛制备成负载型催化剂，进一步制作成整体式催化剂：
用铜盐化合物(如：Cu(NO 3) 2、Cu(Ac) 2和Cu(COOH) 2)为前驱体制备Cu负载型AFI/CHA混晶分子筛催化剂，将铜盐化合物溶于去离子水中配成一定浓度的金属盐溶液，分别称取10g制备好的SAPO-34，SAPO-5和AFI-CHA混晶分子筛倒入铜盐溶液中搅拌30min，连续搅拌至混合物呈现粘稠状以保证铜物种在分子筛中均匀分散。将此混合物静置10h后转移至80℃水浴上干燥6h，然后在马弗炉中500℃焙烧4h，得到Cu/CHA、Cu/AFI和Cu/AFI-CHA负载型催化剂粉末。
将Cu/SAPO-34，Cu/SAPO-5和Cu/AFI-CHA分子筛基催化剂分别通过以下涂覆技术涂覆在堇青石载体上(美国Corning公司，400目，2.5cm 3)制作成整体式催化剂，具体方法如下：
a)将所得Cu/SAPO-34，Cu/SAPO-5和Cu/AFI-CHA分子筛基催化剂粉末分别与醋酸锆、醋酸混合均匀制成涂覆浆液，并控制浆料固含量为45％，浆料中醋酸锆含量为3％，醋酸含量为3％；
b)将涂覆在堇青石蜂窝陶瓷基体上，控制催化剂的上载量180g/L；
c)将涂覆好的基体由室温逐步升温至100℃进行干燥，然后在500℃焙烧4，得到整体式Cu/SAPO-34、Cu/SAPO-5和Cu/AFI-CHA分子筛基催化剂。
上述在负载铜和制备成整体式催化剂是，铜负载量和整体式催化剂上催化剂的上载相同。
采用XRD分析实施例1-4和对比例1-2制备的分子筛的结构，结果如图1所示。可以发现合成了CHA结构的SAPO-34和AFI结构的SAPO-5，以及不同AFI-CHA比例的混晶分子筛。
采用SEM表征单晶和混晶SAPO-n的形貌特征，结果如图2所示。从图中可以看到SAPO-34样品的晶粒呈现出立方块状，与文献报道的SAPO-34典型的 形貌特征相一致。而图中显示AFI-CHA混晶除了有立方块状的晶粒，还出现了六棱柱状的晶粒，这是SAPO-5的典型形貌特征。
催化剂性能测试一：
在实验室自组装的多路固定连续流动的微型反应器中进行NH 3-SCR转化效率测试，模拟的柴油车尾气组成和实验条件见表1。测试之前，先将整体式催化剂在反应气(模拟柴油车尾气)中550℃进行预处理。然后采用降温测试的方法，在每个温度点平衡后进行活性测试。未转化的NO、NO 2和N 2O采用傅立叶红外气体分析仪(Thermol Fisher Scientific)进行测试。
表1：模拟尾气条件
Figure PCTCN2020089513-appb-000001
Cu/CHA、Cu/AFI和Cu/AFI-CHA分子筛催化剂NH 3-SCR活性结果如图5所示。从图5中可以发现，具有AFI结构的对比例2的催化剂表现出较差的NH 3-SCR活性，最高转化率仅在450℃达到65％；实施例2和实施例3的活性与具有CHA结构的对比例1相差不大，而实施例1Cu/AFI-CHA新鲜活性明显高于对比例1，在300-150℃的温度区间内，其最大NO x转化率均相差约13％。
实施例5
为考察AFI-CHA混晶结构对整体式Cu/AFI-CHA催化剂水热稳定性的影响。取10g本发明制备的具有AFI-CHA结构的混晶分子筛按照上述相同方法(等体积浸渍法)制备Cu/AFI-CHA分子筛催化剂。
实施例6
为考察AFI-CHA混晶结构对整体式Cu/AFI-CHA催化剂水热稳定性的影响。将实施例5制备的Cu/AFI-CHA整体式催化剂，在含10vol.％H 2O的流动空气中，800℃水热老化12h后进行活性测试，反应气组成与测试方法与催化剂性能测试一中相同。
对比例3
为考察CHA结构的SAPO-34结构对整体式Cu/CHA催化剂水热稳定性的影响。取10g本发明制备的具有CHA结构的SAPO-34分子筛按照上述相同的等体 积浸渍法制备Cu/CHA分子筛催化剂作为参比催化剂3。然后根据相应的涂覆方法，将得到的Cu/CHA催化剂粉末涂覆到堇青石蜂窝陶瓷基体上，最终得到得Cu/CHA整体式柴油车用NH 3-SCR催化剂。
对比例4
将根据对比例3制备的Cu/CHA整体式催化剂，在含10vol.％H 2O的流动空气中，800℃水热老化不同时间(24～72h)后进行活性测试，反应气组成与测试方法与表1与催化剂性能测试一中相同。
从图3 XRD中可以看到实施例3样品与文献中报道的典型SAPO-34结构衍射峰相符。而实施例5的AFI-CHA混晶分子筛中除了出现SAPO-34结构的XRD衍射峰，也出现了SAPO-5的特征衍射峰。经过高温水热老化后，两个样品的SAPO-34结构衍射峰强都减弱了，但是对比例4单晶样品的SAPO-34衍射峰强减弱的比实施例6混晶样品更加明显。此外，混晶样品中的SAPO-5特征衍射峰在高温水热老化后强度增加了。从XRD的分析结果可知，AFI-CHA混晶样品在高温水热后保持更好的结晶度。
从图4中可以发现两个新鲜样品中的SAPO-34晶粒粒径大小相似，皆为2-5μm。高温水热老化后，Cu/SAPO-34样品中晶粒的形貌遭到了很明显的破坏，大部分立方块状结构遭受破坏，出现无定型结构。反观老化后的Cu/AFI-CHA样品，结构保持的比SAPO-34完整。结果说明混晶Cu/AFI-CHA在高温水热后保持更好的结构完整性，稳定的结构有利于其拥有更优的高温水热稳定性。
图6为对比例3和实施例5分子筛新鲜和高温水热老化催化剂NH 3-SCR活性结果。从图中可以看到在200～450℃的温度区间内，两个新鲜催化剂的NO x转化率很接近，最高转化率约为90％。在低温段(150～200℃)，实施例5的活性比对比例3更好，这是可能是由于混晶AFI-CHA中介孔的比例更大，有利于低温段反应气体的扩散。在高温段(450～550℃)，对比例3催化剂的活性更好。经过高温水热老化后，实施例6的活性保持的比对比例4样品好，实施例6老化催化剂的最高NO x转化率几乎没有下降，而对比例4老化催化剂的最高NO x转化率下降了8％，说明本发明方法制备份催化剂低温活性和水热稳定性更好。
此外，从催化剂N 2O的生成结果可以看到四种催化剂水热老化前后催化剂的N 2O副产物生成量都低于3ppm，说明催化剂在老化前后的N 2选择性都很高。

Claims (10)

  1. 一种AFI-CHA混晶分子筛，其特征在于，由AFI型的SAPO-5分子筛和CHA型的SAPO-34分子筛组成，其晶粒为AFI和CHA的混合晶粒。
  2. 一种基于AFI-CHA混晶分子筛的Cu/AFI-CHA负载型分子筛催化剂，其特征在于，Cu负载在AFI-CHA混晶分子筛上，所述AFI-CHA混晶分子筛由AFI型的SAPO-5分子筛和CHA型的SAPO-34分子筛组成，其晶粒为AFI和CHA的混合晶粒。
  3. 一种整体式催化剂，包括基体和Cu/AFI-CHA负载型催化剂粉末，其中Cu/AFI-CHA负载型催化剂粉负载在堇青石基体上，所述Cu/AFI-CHA负载型催化剂的载体为AFI-CHA混晶分子筛，所述AFI-CHA混晶分子筛由AFI型的SAPO-5分子筛和CHA型的SAPO-34分子筛组成，其晶粒为AFI和CHA的混合晶粒。
  4. 权利要求1所述AFI-CHA混晶分子筛的制备方法，其特征在于，通过水热合成法合成，合成过程中，投料摩尔比按照分子筛中铝：磷：硅：结构导向剂(模板剂)：水的摩尔比为(0.06～0.10)：(0.06～0.10)：(0.040～0.050)：(0.12～0.35)：(0.5～6)进行投料。
  5. 根据权利要求4所述方法，其特征在于，包括以下步骤：
    (1)将拟薄水铝石、磷酸和总用水量中的一部分水混合均匀，搅拌并常温老化制备成P/Al氧化物混合凝胶，再向混合凝胶中添加Si源、结构导向剂和剩余的水，常温静置老化得到混合溶液；
    (2)将混合溶液在120～160℃保温2～20h，再加热到190～210℃保温5～30h，自然冷却到室温后分离出固体，再在500～600℃焙烧5～8h烧除结构导向剂得到AFI～CHA混晶分子筛粉末；
    步骤(1)和步骤(2)中通过改变结构导向剂的投料比例、混合溶液的保温和焙烧温度以及所述温度的升温速率，得到不同AFI/CHA混晶比例的分子筛。
  6. 根据权利要求5所述方法，其特征在于，拟薄水铝石为8～15质量份，磷酸13～23质量份，Si源5～8质量份，结构导向剂1-41质量份。
  7. 根据权利要求5或6所述方法，其特征在于，步骤(2)所述温度的升温速率为3～6℃·min ～1。
  8. 根据权利要求5或6所述方法，其特征在于，所述结构导向剂为三乙胺或四乙基氢氧化铵。
  9. 权利要求1所述混晶分子筛作为载体制备Cu基分子筛催化剂的方法，其特征在 于，用铜盐化合物为前驱体，将AFI-CHA混晶分子筛与铜盐溶液混合搅拌至混合物呈现粘稠状，使用铜在分子筛中均匀分散；然后将混合物静置、水浴干燥后，在马弗炉中300～600℃焙烧3～6h，得Cu/AFI-CHA负载型催化剂粉末。
  10. Cu/AFI-CHA负载型催化剂制备成整体式催化剂的制备方法，其特征在于，将权利要求2所述Cu/AFI～CHA负载型催化剂粉末配成浆料涂覆在堇青石基体上上，催化剂粉末在堇青石上的上载量为120～130g/L；然后将涂覆好的基体于70～150℃干燥，再在300～600℃下焙烧3～6h。
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CN114832853B (zh) * 2022-04-29 2023-06-23 四川大学 一种Cu基混晶分子筛NH3-SCR催化剂及其制备方法
CN114733563B (zh) * 2022-05-10 2023-06-16 中国科学院生态环境研究中心 一种Cu-CHA与H-AEI的复合催化剂及其制备方法与应用
CN114733564B (zh) * 2022-05-10 2023-06-23 中国科学院生态环境研究中心 一种复合沸石scr催化剂及其制备方法与应用
CN117963945A (zh) * 2022-10-24 2024-05-03 中国科学院大连化学物理研究所 一种纳米共晶磷酸硅铝分子筛的制备方法及其应用
CN116078425A (zh) * 2022-12-25 2023-05-09 浙江环化科技有限公司 一种金属杂化共生分子筛及其水热合成方法
CN116532150B (zh) * 2023-04-04 2025-04-11 东南大学 一种糠醛水相加氢反应双构型催化剂及其制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101983103A (zh) * 2008-01-31 2011-03-02 巴斯夫公司 利用具有cha晶体结构的非沸石的含金属分子筛的催化剂、系统和方法
WO2011061835A1 (ja) * 2009-11-19 2011-05-26 イビデン株式会社 ハニカム構造体及び排ガス浄化装置
CN104828842A (zh) * 2014-12-18 2015-08-12 神华集团有限责任公司 一种sapo-5和sapo-34共生的复合分子筛的制备方法
CN106607087A (zh) * 2015-10-21 2017-05-03 中国石油化工股份有限公司 一氧化碳催化转化含氮化合物的催化剂
CN107744830A (zh) * 2017-11-06 2018-03-02 南京工业大学 一步法制备Cu基分子筛SCR催化剂的方法
CN110227540A (zh) * 2019-05-10 2019-09-13 四川大学 Afi-cha混晶分子筛及以其为载体的nh3-scr催化剂以及它们的制备方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060079397A1 (en) * 2004-10-12 2006-04-13 Mertens Machteld M Catalyst and process for the conversion of oxygenates to olefins
US10118166B2 (en) * 2014-06-06 2018-11-06 Uop Llc Zeolitic materials with modified surface composition, crystal structure, crystal size, and/or porosity, methods for making the same, and methods for converting oxygenates to olefins via reactions catalyzed by the same
WO2018172940A1 (en) * 2017-03-20 2018-09-27 Basf Corporation Selective catalytic reduction articles and systems

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101983103A (zh) * 2008-01-31 2011-03-02 巴斯夫公司 利用具有cha晶体结构的非沸石的含金属分子筛的催化剂、系统和方法
WO2011061835A1 (ja) * 2009-11-19 2011-05-26 イビデン株式会社 ハニカム構造体及び排ガス浄化装置
CN104828842A (zh) * 2014-12-18 2015-08-12 神华集团有限责任公司 一种sapo-5和sapo-34共生的复合分子筛的制备方法
CN106607087A (zh) * 2015-10-21 2017-05-03 中国石油化工股份有限公司 一氧化碳催化转化含氮化合物的催化剂
CN107744830A (zh) * 2017-11-06 2018-03-02 南京工业大学 一步法制备Cu基分子筛SCR催化剂的方法
CN110227540A (zh) * 2019-05-10 2019-09-13 四川大学 Afi-cha混晶分子筛及以其为载体的nh3-scr催化剂以及它们的制备方法

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