技术领域technical field
本发明属于氨煤混燃锅炉烟气气体污染物脱除与催化剂材料技术领域，具体涉及一种催化分解N2O耦合催化氧化NH3和CO的复合催化剂制备方法及应用。The invention belongs to the technical field of ammonia-coal co-combustion boiler flue gas pollutant removal and catalyst materials, and specifically relates to a preparation method and application of a composite catalyst for catalytic decomposition ofN2O coupled with catalytic oxidation ofNH3 and CO.
背景技术Background technique
公开该背景技术部分的信息仅仅旨在增加对本发明的总体背景的理解，而不必然被视为承认或以任何形式暗示该信息构成已经成为本领域一般技术人员所公知的现有技术。The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.
NH3选择性催化还原技术(NH3-SCR)是目前工业上最常用的NOx减排技术，可广泛应用于固定源(如各种电厂)和移动源(如柴油发动车)。然而，为了满足日益严格的环保政策对NOx排放浓度的要求，工业界普遍选择增加NH3投入浓度。但这也带来了一个新问题，即NH3的逃逸。此外，由于SCR催化剂本身的N2选择性的限制、SCR反应温度范围的限制以及喷氨均匀性等因素，N2O副产物的生成是不可避免的。另外，燃料如粉煤、柴油等由于燃烧温度、燃料着火方式、氧气浓度等因素的影响，在一定程度上无法完全燃烧，因此会生成CO等小分子碳基副产物。总之，在SCR装置中，实现NOx高效脱除的同时，实现N2O的分解、NH3以及CO的氧化是亟待解决的重要难题。NH3 Selective Catalytic Reduction Technology (NH3 -SCR) is currently the most commonly used NOx emission reduction technology in industry, and can be widely used in stationary sources (such as various power plants) and mobile sources (such as diesel engines). However, in order to meet the increasingly stringent environmental protection policy requirements onNOx emission concentration, the industry generally chooses to increase theNH3 input concentration. But this also brings a new problem, namely the escape of NH3 . In addition, due to the limitations of the N2 selectivity of the SCR catalyst itself, the limitation of the SCR reaction temperature range, and the uniformity of ammonia injection, the formation of N2 O by-products is inevitable. In addition, due to the influence of factors such as combustion temperature, fuel ignition mode, and oxygen concentration, fuels such as pulverized coal and diesel oil cannot be completely combusted to a certain extent, so small molecular carbon-based by-products such as CO will be produced. In short, in the SCR device, it is an important problem to be solved urgently to realize the decomposition of N2 O, the oxidation of NH3 and CO while realizing the efficient removal of NOx .
这些问题在新兴的氨煤混燃锅炉技术中显得尤为突出。氨煤混燃锅炉被视为寻找高效绿色的零碳能源载体来替代传统化石燃料的出色解决方案。然而，氨煤混燃不可避免地导致氨逃逸和燃料不完全燃烧现象的加剧。相比传统NH3选择性催化还原(SCR)过程中NH3过氧化的情况，氨煤混燃引起的NH3燃烧更容易生成高浓度的N2O。因此，业界迫切需要一种能够同时去除N2O、NH3和CO的三效催化剂，尤其是针对氨煤混燃锅炉的应用。这样的三效催化剂可以被设计成在SCR催化剂后添加的一层，最大限度地提高整体系统的净化效率，并满足严格的环保排放要求。These problems are particularly prominent in the emerging ammonia-coal co-fired boiler technology. Ammonia-coal co-fired boilers are regarded as an excellent solution for finding efficient and green zero-carbon energy carriers to replace traditional fossil fuels. However, ammonia-coal co-combustion inevitably leads to the aggravation of ammonia slip and fuel incomplete combustion. Compared with the overoxidation of NH 3in the traditional NH3 selective catalytic reduction (SCR) process, the NH3 combustion caused by ammonia-coal co-combustion is more likely to generate high-concentration N2 O. Therefore, the industry urgently needs a three-way catalyst capable of simultaneously removing N2 O, NH3 and CO, especially for the application of ammonia-coal co-combustion boilers. Such a three-way catalyst can be designed as a layer added after the SCR catalyst to maximize the purification efficiency of the overall system and meet strict environmental protection emission requirements.
传统的N2O分解与NH3-SCO催化剂中，贵金属，如铂、银、金、铑等，在低温下具有高活性，但由于对N2的选择性差，容易形成NOx副产物，以及高昂的成本使其应用受到阻碍。过渡金属氧化物尽管成本低、N2选择性好，但前期在低温下的活性与贵金属相比相对较低。综合来看都不太能满足实际工厂需要。最近，分子筛型催化剂由于特殊性质，引起人们关注。In traditional N2 O decomposition and NH3 -SCO catalysts, noble metals, such as platinum, silver, gold, rhodium, etc., have high activity at low temperatures, but are prone to form NOx by-products due to poor selectivity to N2 , and The high cost hinders its application. Transition metal oxides, despite their low cost and goodN2 selectivity, have relatively low early activity at low temperatures compared to noble metals. On the whole, they are not able to meet the needs of actual factories. Recently, molecular sieve-type catalysts have attracted people's attention due to their special properties.
分子筛是硅铝酸盐物质，它在结构上有许多孔径均匀的孔道和排列整齐的孔穴，具有酸性可调、水热稳定性强等性质，因此是一种优异的载体材料。但对于混氨燃烧锅炉极端工况，金属离子引入后的分子筛氧化还原能力仍显不足，需引入更多的金属活性中心以满足多污染物协同脱除需求。Molecular sieve is an aluminosilicate material. It has many pores with uniform pore size and neatly arranged pores in its structure. It has properties such as adjustable acidity and strong hydrothermal stability, so it is an excellent carrier material. However, for the extreme working conditions of mixed ammonia combustion boilers, the redox ability of molecular sieves after the introduction of metal ions is still insufficient, and more metal active centers need to be introduced to meet the demand for synergistic removal of multiple pollutants.
发明内容Contents of the invention
为了解决上述问题，本发明提供一种可适用于氨煤混燃锅炉烟气中N2O、NH3、CO协同脱除的三效催化剂。具体地涉及金属氧化物-分子筛型催化剂用于氨煤混燃锅炉烟气N2O-NH3-CO协同脱除。In order to solve the above problems, the present invention provides a three-way catalyst applicable to the synergistic removal of N2 O, NH3 , and CO in flue gas of an ammonia-coal co-combustion boiler. Specifically, it relates to a metal oxide-molecular sieve catalyst used for synergistic removal of N2 O-NH3 -CO from ammonia-coal co-combustion boiler flue gas.
为了实现上述目的，本发明采用如下技术方案：In order to achieve the above object, the present invention adopts the following technical solutions:
本发明的第一个方面，提供了一种多污染物协同去除的三效催化剂制备方法，包括：The first aspect of the present invention provides a method for preparing a three-way catalyst for synergistic removal of multi-pollutants, including:
将分子筛进行酸性处理，选择性地脱除非骨架铝，得到脱铝分子筛；Acidic treatment of molecular sieves to selectively remove non-framework aluminum to obtain dealuminated molecular sieves;
将所述脱铝分子筛浸入铁盐或铜盐溶液中，采用离子交换法，获得改性分子筛；Immersing the dealuminated molecular sieve into an iron salt or copper salt solution, and adopting an ion exchange method to obtain a modified molecular sieve;
将所述改性分子筛浸入添加粘合剂的金属前驱体中，50～60℃下浸渍5～8h，于60-100℃下干燥5-12h，于450-550℃下，煅烧5-7h，得到三效催化剂；The modified molecular sieve is immersed in the metal precursor with a binder, immersed at 50-60°C for 5-8 hours, dried at 60-100°C for 5-12 hours, and calcined at 450-550°C for 5-7 hours, A three-way catalyst is obtained;
所述金属前驱体为过渡金属或稀土金属中的至少一种。The metal precursor is at least one of transition metals or rare earth metals.
本发明结合离子交换和浸渍法特点，基于分子筛限域效应，实现多金属活性位点同时出现在分子筛孔道，保证分子筛酸性的同时提升氧化还原能力。同时多类型活性中心，可保证N2O、NH3、CO等反应物分子可定向吸附活化，竞争吸附效果削弱。实现N2O分解、NH3-CO氧化、NH3/CO选择性催化还原N2O等多种反应路径协同进行，展现出良好的反应活性与无害化产物选择性。The present invention combines the characteristics of the ion exchange and impregnation methods, and based on the confinement effect of the molecular sieve, realizes the simultaneous appearance of multi-metal active sites in the pores of the molecular sieve, so as to ensure the acidity of the molecular sieve and improve the redox capacity at the same time. At the same time, multiple types of active centers can ensure that reactant molecules such as N2 O, NH3 , and CO can be adsorbed and activated in a directional manner, and the competitive adsorption effect is weakened. Realize the synergy of various reaction pathways such as N2 O decomposition, NH3 -CO oxidation, NH3 /CO selective catalytic reduction of N2 O, etc., showing good reactivity and selectivity of harmless products.
本发明的第二个方面，提供了上述的方法制备的三效催化剂。The second aspect of the present invention provides the three-way catalyst prepared by the above method.
本发明的第二个方面，提供了上述的三效催化剂在氨煤混燃锅炉烟气气体污染物脱除中的应用。可同时实现N2O分解、NH3氧化、CO氧化。The second aspect of the present invention provides the application of the above-mentioned three-way catalyst in the removal of flue gas pollutants from ammonia-coal co-combustion boilers. N2 O decomposition, NH3 oxidation, and CO oxidation can be realized simultaneously.
本发明的有益效果Beneficial effects of the present invention
(1)本发明在分子筛载体上通过简单的离子交换和粘合浸渍法，实现了多种外来金属位点高度分散，团簇与颗粒大小与显著减少。在保证分子筛本身酸性的同时，氧化还原性提高。多位点的高度分散引入，增强定向吸附与活化，显著减少了竞争吸附，各反应协同效果提升，NH3和CO被氧气氧化的同时可以作为还原剂提高N2O分解活性，同一流程内实现多污染物深度协同治理。(1) The present invention achieves a high degree of dispersion of various foreign metal sites through simple ion exchange and bonding impregnation methods on the molecular sieve carrier, and the size of clusters and particles is significantly reduced. While ensuring the acidity of the molecular sieve itself, the redox property is improved. Highly dispersed introduction of multiple sites, enhanced directional adsorption and activation, significantly reduced competitive adsorption, improved synergistic effect of each reaction, NH3 and CO can be used as reducing agents to improve N2 O decomposition activity while being oxidized by oxygen, realized in the same process In-depth collaborative governance of multiple pollutants.
(2)本发明以酸性分子筛为载体，非贵金属氧化物纳米颗粒为活性组分，酸性与还原性协同耦合，实现N2O分解与NH3-CO氧化协同反应效应。(2) The present invention uses acidic molecular sieves as the carrier and non-noble metal oxide nanoparticles as the active component, and acidity and reduction are synergistically coupled to realize the synergistic reaction effect of N2 O decomposition and NH3 -CO oxidation.
(3)本发明制备方法简单、实用性强，易于推广。(3) The preparation method of the present invention is simple, practical and easy to popularize.
附图说明Description of drawings
构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示例性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute improper limitations to the present invention.
图1为实施例1制得的三效催化剂的反应活性曲线，包括NH3转化率、CO转化率及N2O转化率。Fig. 1 is the reaction activity curve of the three-way catalyst prepared in Example 1, including NH3 conversion rate, CO conversion rate and N2 O conversion rate.
图2为固定床脱硝反应实验台，反应条件如下：模拟烟气流量为2000mL/min，其中N2O、NH3、CO、O2的百分含量分别为：0.05％、0.1％、0.1％、3.0％，N2作平衡气体，空速比(GHSV)设定为30,000h-1。催化反应测试的温度区间为200-500℃。Figure 2 is a fixed bed denitrification reaction test bench, the reaction conditions are as follows: the simulated flue gas flow rate is 2000mL/min, and the percentages of N2 O, NH3 , CO, and O2 are respectively: 0.05%, 0.1%, and 0.1% , 3.0%, N2 was used as the balance gas, and the space velocity ratio (GHSV) was set at 30,000h-1 . The temperature range of the catalytic reaction test is 200-500°C.
其中：1、质量流量计；2、气体预混器；3、烟气预热段；4、温控仪；5、固定床石英反应器；6、浓磷酸；7、干燥瓶；8、烟气分析仪。Among them: 1. Mass flow meter; 2. Gas premixer; 3. Flue gas preheating section; 4. Temperature controller; 5. Fixed bed quartz reactor; 6. Concentrated phosphoric acid; 7. Drying bottle; 8. Smoke gas analyzer.
具体实施方式Detailed ways
应该指出，以下详细说明都是示例性的，旨在对本发明提供进一步的说明。除非另有指明，本发明使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
一种多污染物协同去除的三效催化剂制备方法，包括：A method for preparing a three-way catalyst for synergistic removal of multiple pollutants, comprising:
将分子筛进行酸性处理，选择性地脱除非骨架铝，得到脱铝分子筛；Acidic treatment of molecular sieves to selectively remove non-framework aluminum to obtain dealuminated molecular sieves;
将所述脱铝分子筛浸入铁盐或铜盐溶液中，采用离子交换法，获得改性分子筛；Immersing the dealuminated molecular sieve into an iron salt or copper salt solution, and adopting an ion exchange method to obtain a modified molecular sieve;
将所述改性分子筛浸入添加粘合剂的金属前驱体中，50～60℃下浸渍5～8h，于60-100℃下干燥5-12h，于450-550℃下，煅烧5-7h，得到三效催化剂；The modified molecular sieve is immersed in the metal precursor with a binder, immersed at 50-60°C for 5-8 hours, dried at 60-100°C for 5-12 hours, and calcined at 450-550°C for 5-7 hours, A three-way catalyst is obtained;
所述金属前驱体为过渡金属或稀土金属中的至少一种。The metal precursor is at least one of transition metals or rare earth metals.
为了实现NH3、N2O、CO等多分子的不同位点定向吸附，必须要求有不同的活性位点，对于分子筛，可通过引入两种或三种外来金属构建不同的活性位点。离子交换法是最常用的引入金属的方法，但是当需要两种或三种同时引入时，若是只使用离子交换法，由于不同金属离子具有不同的尺寸和化学性质，会出现竞争交换等作用，相互影响各自的引入。为此，本发明经过长期实验摸索和系统的研究发现：在离子交换法的基础，结合浸渍法和粘结剂，可以避免由于结合力弱，可能会出现较大的团簇的问题，使金属更加分散。结合这两种方法，实现多金属的高分散的引入。In order to realize the directional adsorption of NH3 , N2 O, CO and other multi-molecules at different sites, different active sites must be required. For molecular sieves, different active sites can be constructed by introducing two or three foreign metals. Ion exchange method is the most commonly used method to introduce metals, but when two or three kinds of metals are required to be introduced at the same time, if only ion exchange method is used, since different metal ions have different sizes and chemical properties, there will be effects such as competitive exchange, Interact with each other's imports. For this reason, the present invention has found through long-term experimental exploration and systematic research: on the basis of the ion exchange method, combined with the impregnation method and the binder, the problem of larger clusters that may occur due to weak binding force can be avoided, and the metal more scattered. Combining these two methods, a highly dispersed introduction of polymetallics is achieved.
本发明提供了一种适用于氨煤混燃锅炉的N2O-NH3-CO协同脱除工况的催化剂制备方法，催化剂包括改性分子筛载体、负载金属活性组分等。通过对商业购买的分子筛载体脱铝处理掉骨架外Al，并结合离子交换改变分子筛内部负电荷，使其出现更多的酸，提高分子筛载体的酸性。同时使用简便的湿式浸渍结合络合剂法将过渡金属或稀土元素等高度分散在分子筛孔道内部，使氧化还原性能显著提升。The invention provides a catalyst preparation method suitable for the N2 O-NH3 -CO synergistic removal working condition of an ammonia-coal co-combustion boiler. The catalyst includes a modified molecular sieve carrier, a loaded metal active component, and the like. Dealing with commercially purchased molecular sieve supports to remove the Al outside the framework, combined with ion exchange to change the negative charge inside the molecular sieve, making it appear more Acid, improve the acidity of the molecular sieve carrier. At the same time, transition metals or rare earth elements are highly dispersed in the pores of molecular sieves by using a simple wet impregnation method combined with a complexing agent, which significantly improves the redox performance.
具体地，本发明的制备方法如下：Specifically, the preparation method of the present invention is as follows:
步骤1，将成型商业分子筛进行酸性处理，通过控制酸性溶液的性质和用量，选择性的脱除非骨架铝，得到酸处理后的脱铝分子筛。In step 1, acid treatment is carried out on the formed commercial molecular sieve, and the non-framework aluminum is selectively removed by controlling the nature and dosage of the acid solution to obtain the dealuminated molecular sieve after acid treatment.
步骤2，将酸处理后的脱铝分子筛浸入金属前驱体中，利用离子交换法，获得金属与分子筛骨架紧密相连的改性分子筛。In step 2, the acid-treated dealuminated molecular sieve is immersed in a metal precursor, and an ion exchange method is used to obtain a modified molecular sieve in which the metal and the molecular sieve framework are closely connected.
步骤3，将步骤2获得的分子筛浸入添加粘合剂的不同于步骤2中的金属前驱体当中，利用浸渍法，获得金属纳米颗粒均匀分散在分子筛孔道内的催化剂。Step 3, immersing the molecular sieve obtained in step 2 into a metal precursor different from that in step 2 with the addition of a binder, and using an impregnation method to obtain a catalyst in which metal nanoparticles are uniformly dispersed in the pores of the molecular sieve.
在一些实施例中，所述商业分子筛可包括常见用于气体污染物脱除领域的商业分子筛，如MFI型ZSM-5、CHA型SSZ-13、Beta型、HY型等，优选的为ZSM-5型分子筛。In some embodiments, the commercial molecular sieves may include commercial molecular sieves commonly used in the field of gas pollutant removal, such as MFI type ZSM-5, CHA type SSZ-13, Beta type, HY type, etc., preferably ZSM- Type 5 molecular sieve.
在一些实施例中，所述分子筛中的硅铝比为15～100。In some embodiments, the silicon-aluminum ratio in the molecular sieve is 15-100.
在一些实施例中，所述酸处理采用硝酸，酸的浓度为0.2～1.0mol/L；In some embodiments, nitric acid is used for the acid treatment, and the concentration of the acid is 0.2-1.0 mol/L;
选择硝酸主要是因为在抽滤过程中可以洗掉大量的硝酸根离子，且即使在催化剂的表面上仍有硝酸根的残留，也可在煅烧过程中分解掉、挥发掉。但是使用盐酸沉积的氯离子，或者使用硫酸沉积的硫酸根离子，都不能得到很好的去除。The main reason for selecting nitric acid is that a large amount of nitrate ions can be washed off during the suction filtration process, and even if there are still nitrate residues on the surface of the catalyst, they can be decomposed and volatilized during the calcination process. However, chloride ions deposited with hydrochloric acid, or sulfate ions deposited with sulfuric acid, cannot be removed well.
在一些实施例中，酸的用量与分子筛质量比为1～30:1。In some embodiments, the mass ratio of the amount of the acid to the molecular sieve is 1-30:1.
在一些实施例中，所述铁盐或铜盐选自硝酸铜、硝酸铁、氯化铜、氯化铁。In some embodiments, the iron or copper salt is selected from copper nitrate, ferric nitrate, copper chloride, ferric chloride.
在一些实施例中，所述离子交换法的具体步骤包括：将所述脱铝分子筛浸入铁盐或铜盐溶液中，固液比为1:3-5g/mL，搅拌3～5小时，抽滤洗涤并在60-100℃下干燥5-6h，450-550℃下煅烧5-7h，得到改性分子筛。In some embodiments, the specific steps of the ion exchange method include: immersing the dealuminated molecular sieve in an iron salt or copper salt solution with a solid-liquid ratio of 1:3-5g/mL, stirring for 3-5 hours, and pumping Filter and wash, dry at 60-100°C for 5-6h, and calcinate at 450-550°C for 5-7h to obtain a modified molecular sieve.
在一些实施例中，用粘合浸渍的金属前驱体为锰、钴、铈、铼、钼等过渡金属或稀土金属中一种或多种的常规使用的前驱体，如硝酸盐、碳酸盐、氯化盐、醋酸盐等。优选的为，硝酸锰与硝酸铈。In some embodiments, the metal precursor impregnated with bonding is a conventionally used precursor of one or more transition metals such as manganese, cobalt, cerium, rhenium, molybdenum or rare earth metals, such as nitrate, carbonate , Chloride, acetate, etc. Preferred are manganese nitrate and cerium nitrate.
在一些实施例中，所述改性分子筛与金属前驱体的固液比为1:5-10g/mL。In some embodiments, the solid-to-liquid ratio of the modified molecular sieve to the metal precursor is 1:5-10 g/mL.
在一些实施例中，所述粘结剂为柠檬酸；其酸性不足于对分子筛载体上的活性位点产生影响，但可以均匀地粘结如Mn，Ce等纳米颗粒于分子筛孔道内，阻止颗粒聚集成大尺寸氧化物，保证催化反应活性。与未加粘结剂的催化剂相比，活性纳米颗粒分散度显著提升，活性稳定性也有较大的提升。In some embodiments, the binder is citric acid; its acidity is not enough to affect the active sites on the molecular sieve carrier, but it can evenly bind nanoparticles such as Mn and Ce in the pores of the molecular sieve, preventing the particles from Aggregate into large-sized oxides to ensure catalytic activity. Compared with the catalyst without binder, the dispersion of active nanoparticles is significantly improved, and the activity stability is also greatly improved.
在一些实施例中，所述粘结剂与改性分子筛的质量比为0.5～2:1。In some embodiments, the mass ratio of the binder to the modified molecular sieve is 0.5˜2:1.
下面结合具体的实施例，对本发明做进一步的详细说明，应该指出，所述具体实施例是对本发明的解释而不是限定。The present invention will be described in further detail below in conjunction with specific examples. It should be pointed out that the specific examples are to explain rather than limit the present invention.
实施例1Example 1
取一定量的商用ZSM-5型分子筛，Si/Al＝40，与0.2mol/L的硝酸溶液混合(两者质量比为10:1)，在50℃下搅拌3小时，抽滤洗涤并在100℃下干燥5h，获得脱铝分子筛ZSM-5-Al。之后取一定量的ZSM-5-Al依次放入硝酸铵、硝酸铜溶液中(固液比为1:3)，各磁力搅拌3小时，抽滤洗涤并在100℃下干燥5h，500℃煅烧得到Cu-ZSM-5催化剂。最后，将一定量地Cu-ZSM-5研磨后再次浸入硝酸锰溶液中(固液比为1:5)，同时加入柠檬酸(柠檬酸与分子筛载体质量比为2:1)，50℃下持续搅拌5小时，抽滤洗涤并在100℃下干燥5h，500℃煅烧后获得所需产物MnCe/Cu-ZSM-5。Take a certain amount of commercial ZSM-5 type molecular sieve, Si/Al=40, mix with 0.2mol/L nitric acid solution (the mass ratio of the two is 10:1), stir at 50°C for 3 hours, wash with suction and put in Dry at 100°C for 5 hours to obtain dealuminated molecular sieve ZSM-5-Al. After that, take a certain amount of ZSM-5-Al and put it into ammonium nitrate and copper nitrate solution (solid-to-liquid ratio: 1:3), each magnetically stirred for 3 hours, filtered and washed, dried at 100°C for 5h, and calcined at 500°C A Cu-ZSM-5 catalyst was obtained. Finally, a certain amount of Cu-ZSM-5 was ground and then immersed in manganese nitrate solution (solid-to-liquid ratio: 1:5), while adding citric acid (mass ratio of citric acid to molecular sieve carrier: 2:1), at 50°C Stir continuously for 5 hours, wash with suction and dry at 100°C for 5h, and calcined at 500°C to obtain the desired product MnCe/Cu-ZSM-5.
通过活性测试与表征可以发现该催化剂协同脱除效果良好，N2O转化率可在350℃以上时保持在90％以上，NH3在300-450℃范围内保持在90％以上，CO转化率可在200℃以上均保持100％。如图1所示。Through the activity test and characterization, it can be found that the catalyst has a good synergistic removal effect. The conversion rate of N2 O can be maintained above 90% at 350°C, and the conversion rate of NH3 can be maintained above 90% in the range of 300-450°C. The conversion rate of CO It can maintain 100% above 200°C. As shown in Figure 1.
实施例2Example 2
与实施例1的不同之处在于，采用硝酸铁溶液替代硝酸铜溶液。The difference from Example 1 is that ferric nitrate solution is used instead of copper nitrate solution.
实施例3Example 3
与实施例1的不同之处在于，采用硝酸铈溶液替代硝酸锰溶液。The difference from Example 1 is that cerium nitrate solution is used instead of manganese nitrate solution.
实施例4Example 4
与实施例1的不同之处在于，采用硝酸铈和硝酸锰溶液(锰铈前驱体比例为1:1)替代硝酸锰溶液。The difference from Example 1 is that the manganese nitrate solution is replaced by cerium nitrate and manganese nitrate solution (the ratio of manganese cerium precursor is 1:1).
实施例5Example 5
与实施例1的不同之处在于，采用硝酸钴溶液替代硝酸锰溶液。The difference from Example 1 is that cobalt nitrate solution is used instead of manganese nitrate solution.
实施例6Example 6
与实施例1的不同之处在于，采用硝酸铼溶液替代硝酸锰溶液。The difference from Example 1 is that rhenium nitrate solution is used instead of manganese nitrate solution.
实施例7Example 7
与实施例1的不同之处在于，采用钼酸铵溶液替代硝酸锰溶液。The difference from Example 1 is that ammonium molybdate solution is used instead of manganese nitrate solution.
对比例1Comparative example 1
与实施例1的不同之处在于，未进行“离子交换处理”，未负载铜。The difference from Example 1 is that "ion exchange treatment" was not performed, and copper was not supported.
对比例2Comparative example 2
实施例1中“离子交换处理”制备的Cu-ZSM-5催化剂。The Cu-ZSM-5 catalyst prepared by "ion exchange treatment" in Example 1.
对比例3Comparative example 3
与实施例1的不同之处在于，未进行“离子交换处理”，采用浸渍法同时负载铜和锰。The difference from Example 1 is that the "ion exchange treatment" is not carried out, and the impregnation method is used to simultaneously support copper and manganese.
采用固定床脱硝反应实验台(图2)，对催化剂的性能进行测试，反应条件如下：模拟烟气流量为2000mL/min，其中N2O、NH3、CO、O2的百分含量分别为：0.05％、0.1％、0.1％、3.0％，N2作平衡气体，空速比(GHSV)设定为30,000h-1。催化反应测试的温度区间为200-500℃。各实施例和对比例在300℃下的转化率如表1所示。The performance of the catalyst was tested using the fixed bed denitrification reaction test bench (Fig. 2). The reaction conditions were as follows: the simulated flue gas flow rate was 2000mL/min, and the percentage contents of N2 O, NH3 , CO, and O2 were respectively : 0.05%, 0.1%, 0.1%, 3.0%, N2 is used as the balance gas, and the space velocity ratio (GHSV) is set to 30,000h-1 . The temperature range of the catalytic reaction test is 200-500°C. The conversion rates at 300° C. of various examples and comparative examples are shown in Table 1.
表1Table 1
*烟气流量为2000mL/min，其中N2O、NH3、CO、O2的百分含量分别为：0.05％、0.1％、0.1％、3.0％，N2作平衡气体，空速比(GHSV)为30000h-1。反应温度为300℃。* The flue gas flow rate is 2000mL/min, and the percentage contents of N2 O, NH3 , CO, and O2 are respectively: 0.05%, 0.1%, 0.1%, and 3.0%, and N2 is used as the balance gas, and the space velocity ratio ( GHSV) is 30000h-1 . The reaction temperature was 300°C.
由实施例1和对比例1的对比可知，“未负载铜”的催化剂不能对N2O进行分解，NH3和CO转化率也下降明显。From the comparison of Example 1 and Comparative Example 1, it can be seen that the "unsupported copper" catalyst cannot decompose N2 O, and the conversion rates of NH3 and CO also drop significantly.
由实施例1和对比例2的对比可知，与Cu-ZSM-5催化剂相比，多种外来金属位点高度分散引入，增强定向吸附与活化，显著减少了竞争吸附，各反应协同效果提升，NH3和CO被氧气氧化的同时可以作为还原剂提高N2O分解活性，同一流程内实现多污染物深度协同治理。From the comparison of Example 1 and Comparative Example 2, it can be seen that compared with the Cu-ZSM-5 catalyst, a variety of foreign metal sites are highly dispersed and introduced, which enhances directional adsorption and activation, significantly reduces competitive adsorption, and improves the synergistic effect of each reaction. When NH3 and CO are oxidized by oxygen, they can be used as reducing agents to improve the decomposition activity of N2 O, and achieve multi-pollutant deep synergistic treatment in the same process.
由实施例1和对比例3的对比可知，单纯的浸渍法负载多金属，会出现不同金属位点的分散不均匀，团簇与颗粒大小显著增大，竞争吸附作用较强，N2O、NH3、CO同时脱除效果较差。From the comparison of Example 1 and Comparative Example 3, it can be seen that the simple impregnation method for loading multi-metals will lead to uneven dispersion of different metal sites, a significant increase in the size of clusters and particles, strong competitive adsorption, and N2 O, The simultaneous removal of NH3 and CO is poor.
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
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