Regenerable fine SCR (Selective Catalytic Reduction) denitration catalyst system

Abstract

The present application relates to a repeatedly renewable fine SCR denitration catalyst system, comprising: a catalyst module suitable for replacement, comprising a renewable low temperature SCR denitration catalyst, the working temperature of which is below 300 DEG C; a reactor for accommodating the catalyst module; the injection system is used for injecting a reducing agent into the reactor, and the renewable low-temperature SCR denitration catalyst comprises a carrier framework formed by thermoplastic plastic; the low-temperature SCR denitration catalytic active component is compounded in the carrier framework and is supported by the carrier framework; the deactivated catalyst module is detached and replaced with a new catalyst module or a regenerated catalyst module, so that the fine SCR denitration catalyst system is quickly regenerated and recycled; the regenerated catalyst module is obtained by re-forming and regenerating the renewable low-temperature SCR denitration catalyst in the inactivated catalyst module; the reproducible low-temperature SCR denitration catalyst can be regenerated through the re-forming of the carrier framework of the thermoplastic plastic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of SCR catalyst, and particularly to the structure and configuration of a fine SCR denitration catalyst system for nitrogen oxides (NO x ).

[0002] More particularly, the present application relates to a fine SCR denitration catalyst system capable of multiple regeneration, which is suitable for but not limited to a wide range of application scenarios such as industrial flue gas denitration applications, ship and automobile exhaust treatment, thermal power plants, incineration plants, cement plants, gas scrubbing equipment, etc. BACKGROUND

[0003] Nitrogen oxides (NO x ) are one of the most important atmospheric pollutants at present, and their excessive emission not only seriously threatens human health, but also causes a series of environmental problems. At present, the proportion of flue gas NO x emission in non-electricity industries in China is increasing year by year, and the realization of flue gas emission reduction in non-electricity industries is the focus of atmospheric pollution prevention and control work at the present stage.

[0004] Research and practice have found that ammonia-selective catalytic reduction (NH3-SCR) is the most mature technology for controlling NO x emission at present, and is one of the best technologies for controlling NO x emission, and the catalyst is the core of the SCR technology.

[0005] At present, the mainstream commercialized SCR denitration catalyst is a vanadium-based monolithic honeycomb catalyst (V2O5-WO3-TiO2), and its catalyst forming technology includes monolithic honeycomb, plate and corrugated plate forming, which is mainly prepared by using titanium dioxide as the paste material. The preparation process is not only complex, but also cannot tolerate errors. Once the forming process deviates from the best working condition of the forming process, the catalyst will be discarded because it cannot meet the use requirements. Moreover, the catalyst is prone to breakage during transportation, resulting in product loss. In addition, due to the large density of this type of vanadium-based catalyst, it is difficult to apply it in equipment scenarios such as ships and automobiles, which have strict requirements on the weight of the catalyst.

[0006] In addition, the desired denitration temperature of flue gas of large-scale non-fire power plant, cement kiln, industrial boiler and the like is mostly below 300°C. The existing low-temperature denitration catalyst is easily affected by fly ash, SO2, H2O and the like in the actual production operation process, leading to rapid deactivation of the catalyst and inability to be used normally for a long time. The used catalyst (which cannot meet the denitration requirements due to wear or deactivation and the like) is generally discarded directly, which not only wastes resources but also easily causes environmental pollution by being discarded at will. Although there are currently some studies on cleaning and regeneration of the catalyst, such as cleaning by ultrasonic cleaning and then acid / alkali washing and the like to restore the activity. However, in the production process of the existing technology, on the one hand, the cost of cleaning and regeneration of the catalyst is relatively high (about 40% of the price of a new catalyst, and the chemical life is 80% of that of a new catalyst), and the catalyst after multiple services cannot be recycled, which is not a recycling method with economic and environmental benefits. On the other hand, the chemical cleaning process generally inevitably causes pollution. In other words, the disposal and recycling of the catalyst also causes more costs, more complex post-treatment and more serious environmental pollution and the like.

[0007] The technology of loading a catalyst with a noble metal base by impregnation method, although it is beneficial to the recovery and utilization of the noble metal component to a certain extent, still has other losses in the extraction and filtration process, so that the noble metal active substance cannot be completely recovered. Moreover, the recovery process still causes a large amount of wastewater, some toxic gases and only a low recovery rate, and the process method needs to be further improved.

[0008] The existing vanadium-based catalyst (V2O5-WO3TiO2) has problems of complex preparation process (calcination for 20-30 days is required), low mechanical strength (easy to be broken during transportation), difficulty in regeneration (acid / alkali washing is required, and the cost is high) and environmental pollution and the like. In addition, the low-temperature denitration catalyst is easily poisoned by SO2 and H2O, and the disposal cost of the discarded catalyst is high and the environment is polluted.

[0009] The advanced preparation technology and regeneration technology of the industrial denitration catalyst after deactivation are still a big problem to be solved for the denitration catalyst at present.

[0010] In actual production and application of enterprises, the yield of catalyst preparation, breakage during transportation and deactivation of the catalyst in the actual working environment are difficult to avoid, and there is a long-term demand in the industry that the catalyst can be operated stably, with high performance and high reliability, for a longer time at a lower price. However, the current preparation and regeneration technology cannot make the catalyst operate at a relatively low operating cost and always maintain a relatively high catalytic activity.

[0011] Moreover, the discarded catalysts cannot be easily disposed of in an environmentally friendly manner because they contain harmful substances such as heavy metals, which can easily enter the environment during loading, transportation, storage, and disposal, and then harm the environment and the health of living beings (including humans) through contact, inhalation, and food chain, and even cause cancer. Some discarded catalysts also contain toxic components such as arsenic trioxide, arsenic pentoxide, chromium trioxide (as an example, not a common toxic component in denitration catalysts, can be replaced by vanadium pentoxide, a common component in denitration catalysts), and the like. If not properly disposed of, they will occupy space, pollute water and soil, release harmful gases, and increase air particulate matter. If properly disposed of to meet environmental and legal requirements, the high cost of materials, equipment, and processes required to dispose of the waste makes it essentially impractical for industrial use. The above chemical waste catalysts, including the above-mentioned discarded catalysts, cannot be treated as general solid waste and must be entrusted to professional units with hazardous waste operating permits for recycling, utilization, and disposal to prevent environmental risks and ensure health and safety.

[0012] A Chinese patent application for invention with publication number CN117019136A, filed by the same inventor as this application on July 28, 2023, discloses a monolithic low-temperature manganese / cerium honeycomb denitration catalyst, which is prepared by using cerium dioxide (CeO2) and manganese oxide (MnO x ) as the main active components, titanium dioxide (TiO2) as the paste material, and adding a structure aid, and using an extrusion method. The catalyst was evaluated for catalytic activity and SO2 poisoning resistance by simulating the test environment of actual industrial flue gas. Experimental data show that the catalyst exhibits excellent low-temperature denitration activity and SO2 poisoning resistance, and can achieve removal of nitrogen oxides in low-temperature flue gas in actual industrial applications.

[0013] However, the existing catalyst preparation process uses inorganic materials such as TiO2 as the paste material, which is prone to sintering and will lose its adhesion after multiple calcinations, making it impossible to use normally; the yield of the catalyst, damage during transportation, and deactivation of the catalyst in actual working conditions are difficult to avoid. The TiO2 material after multiple calcinations will reduce the mechanical strength of the catalyst and damage its structure, resulting in the catalyst being scrapped due to its inability to be used. Moreover, the mechanical strength of the catalyst prepared using TiO2 as the paste material is limited, and it is brittle, which makes it prone to damage and breakage during transportation and use.

[0014] In addition, during the recycling and disposal of catalysts after deactivation, such as catalyst regeneration and hazardous waste disposal, the recovery of active components from a large amount of TiO2 requires a large amount of energy, resulting in a large amount of energy waste and environmental pollution problems.

[0015] In summary, the catalyst regeneration and recycling treatment technology in the prior art has high difficulty and cost, and the technical effect and economic benefit are not good, so it is not widely used and has a bleak prospect; the treatment of hazardous waste catalyst in the prior art is easy to cause resource waste and environmental pollution; the active substance extraction technology of the catalyst in the prior art, such as hydrometallurgy, pyrometallurgy and the like, has a complicated process, high energy consumption and long time consumption; the cleaning and active substance reloading (packing) of the catalyst in the prior art during regeneration not only has a complicated process step, but also greatly reduces the mechanical strength of the final regenerated catalyst product and the regenerated catalytic performance; the paste remolding of the catalyst in the prior art in terms of regeneration and waste treatment affects the mechanical strength, and the hazardous waste needs special treatment.

[0016] Therefore, based on at least the above, there is a continuous need in the industry to innovate and create in the related preparation, material, structure, molding, regeneration and the like of the SCR catalyst, and to improve the existing catalyst molding and the like technical mode. It is desirable to innovatively improve or realize a remoldable, easy-to-treat and material-recyclable, regenerated and recycled molded catalyst and system, to alleviate or even overcome the defects of the prior art, and to realize more beneficial technical effects and technical progress. SUMMARY

[0017] The present application is proposed in view of the above and other more ideas.

[0018] The inventors of the present application surprisingly found through research and repeated experiments and test verifications that the catalyst supported by the polymer (as a substrate / carrier / skeleton) can be regenerated and reused. The present application proves through research and tests that the catalyst of the polymer substrate (or carrier / skeleton) can be regenerated by a simplified remolding process suitable for industrialized scale production, realize multiple uses, greatly reduce the material and production cost, and greatly reduce or even substantially eliminate the negative impact on the environment.

[0019] One of the purposes of the present application is to provide a fine SCR denitration catalyst system capable of remolding and multiple regeneration, and a replaceable / remoldable regenerated low-temperature SCR catalyst module, which uses a thermoplastic plastic as a carrier skeleton and contains a low-temperature SCR catalytically active component dispersed and supported in the carrier skeleton formed by the thermoplastic plastic. Thus, through the preparation, remolding and regeneration of the low-temperature SCR catalyst, the fine SCR denitration catalyst system of the present application can also be remolded and regenerated multiple times, and through the segmented configuration of the catalyst module but not limited to it, easier replacement / remolding and regeneration, and fine SCR denitration are realized.

[0020] The inventors of the present application surprisingly found that the thermoplastic catalyst molding process of the present application can use thermoplastic materials instead of TiO2or the like as the skeleton (carrier) material of the catalyst; at the same time, the powder catalyst component can be used as a binder for thermoplastic materials to help the various components / structures of the molded thermoplastic SCR catalyst to be better bonded and combined together. Finally, through the concept and technology of the present application, the powder catalyst thermoplastic is first molded and repeatedly molded into an industrial catalyst with substantially stable and unchanged catalyst activity, stable surface physical and chemical properties, strong and light, and can be repeatedly molded and regenerated, which can replace the existing low-temperature denitration catalyst, and can be applied to a wide range of applications including ships, automobiles, thermal power plants, incineration plants, cement plants, gas scrubbing equipment, etc. which require lightweight catalysts.

[0021] According to an aspect of the basic application concept of the present application, a low-temperature SCR catalyst is provided, in which thermoplastic plastic is used instead of traditional carrier materials such as TiO2as a traditional skeleton (carrier) material, the preparation process is simplified by molding processes such as thermoplastic / thermopressing / extrusion, etc., and the pore / channel structure of the catalyst can be selectively increased by pore-forming agents. The low-temperature SCR catalyst can be regenerated by remolding after crushing after deactivation, realizing regeneration and recycling.

[0022] Some important aspects of the inventive concept of the present application are further described as follows:

[0023] (1) Thermoplastic plastic can be used instead of traditional carrier materials such as TiO2as a catalyst carrier skeleton material, simplifying and facilitating the preparation process and regeneration process of the catalyst.

[0024] Industrial denitration catalysts (nitrogen oxides (NO xGenerally, TiO2 and other materials are used as the main paste material, and active components are mixed into the mud during the molding process or are impregnated into the support material after the preparation of the support material, and then the finished catalyst is obtained after calcination and cutting. The calcination process causes the active substance to precipitate from the solution and also causes the support material to sinter and thus adhere more closely together. The production of a batch of catalysts requires processes such as mixing, kneading, aging, extrusion, drying, calcination, and cutting, which takes about 20-30 days. The present application uses thermoplastic plastic as the carrier skeleton material instead of the existing process, which only needs to mix thermoplastic powder and catalyst powder, and then perform a thermoplastic process in a mold. Due to the special surface properties of the plastic material, there is almost no mold sticking, and the desired monolithic catalyst material can be obtained from the raw materials in a very short time. The preparation by hot pressing method requires even shorter time. The method reported in the present application is limited by the hot melting temperature of the plastic material, which is lower than the calcination temperature of TiO2 material, and the heating time is shorter, and there is no need for a drying process, and the integrated rapid forming is achieved.

[0025] (2) The low-temperature denitration catalyst is loaded on the polymer material (i.e. thermoplastic plastic material) to perform integrated monolithic forming, thereby improving the mechanical strength of the monolithic catalyst.

[0026] The industrial catalyst prepared by the traditional process generally uses TiO2 and other materials as the main paste material, which has a certain mechanical strength. However, different denitration catalysts use different active components, and the addition of active components can improve the catalytic activity of the catalyst, but too much active component will reduce the adhesion of the TiO2 paste, resulting in embryo breakage, damage, etc. during the drying process. Even if there is no breakage or cracking during the preparation process, there is also a probability of catalyst breakage and damage after calcination due to uneven heating and excessive active component in some areas. More likely, the catalyst prepared from TiO2 and other materials is prone to extrusion and collision during transportation, causing breakage and damage. In addition, the catalyst with insufficient mechanical strength will collapse and break due to excessive flue gas flow rate during use, and can no longer be used.

[0027] The preparation method using thermoplastic plastic as the carrier skeleton material introduced in the present application can use thermoplastic plastic material as the main body of the catalyst, which has stable physical and chemical properties and excellent mechanical strength. The catalyst can maintain the integrity of the catalyst during normal transportation and use, and can withstand greater flue gas pressure drop. In addition, the preparation process does not require long-time drying and calcination, but only one thermoplastic process, which greatly simplifies the process flow, reduces the possibility of low yield caused by process flow, and waste catalyst caused by misoperation can be remolded, saving resources.

[0028] In addition, various thermoplastics can be used to support the catalyst material stably and smoothly because their softening temperatures are higher than the working temperature window of the catalyst.

[0029] (3) The addition of pore-forming agents provides more pore structures for the catalyst

[0030] During the thermoplastic molding process, bubbles and cavities are generated due to uneven heating in the mold, which is undesirable in the preparation of plastic parts, but is desirable in the preparation of catalysts. The bubbles and channel structures can effectively increase the specific surface area and expose more catalyst active sites, thereby improving the catalytic activity. On this basis, we added a pore-forming agent during the thermoplastic process and increased the water washing / solution immersion process to remove it (e.g., by dissolution), so that the final product can have more pore structures.

[0031] (4) Simplify the catalyst regeneration process and make the catalyst recyclable.

[0032] The main reasons for catalyst deactivation are fly ash clogging the catalyst pores and the catalyst being affected by SO2 and H2O, which leads to catalyst deactivation. For deactivated catalysts, we can simply clean them by washing off the fly ash and deposited ammonium sulfate salt components on the surface of the catalyst, then physically crush the molded catalyst into powder, and then perform the thermoplastic molding process again. During the crushing process, all the crushed powder samples are collected, and during the reshaping process, only a small amount of catalyst powder needs to be added. After reshaping, the sample size hardly changes, the catalytic activity does not decrease, and the catalyst can almost be recycled.

[0033] (5) Change of substrate material to make the catalyst resistant to water poisoning.

[0034] Polymer materials can be used as catalyst carriers to solve the problem of water poisoning due to their stable physical and chemical properties and non-wetting surfaces. In other catalytic reactions, polymer substrates can effectively promote the rapid departure of water and improve reaction activity. Physical mixing of catalyst powder and hydrophobic polymer materials has been proven to improve the water poisoning resistance of the catalyst. This application uses thermoplastics as catalyst carrier materials. After the catalyst powder and thermoplastics are thoroughly mixed, for example, thermoplastic molding, there may be an immersion process during preparation, but it does not affect the catalytic activity of the catalyst because the hydrophobic polymer matrix material enables the catalyst to have good water poisoning resistance.

[0035] According to the concept of one aspect of the present application, there is provided a fine SCR De-NOx catalyst system capable of being reshaped and regenerated multiple times, comprising: a catalyst module configured to be replaceable, which contains a regenerable low-temperature SCR De-NOx catalyst, wherein the low-temperature SCR catalyst has an operating temperature of 300°C or less; a reactor for accommodating the catalyst module; a spraying system for spraying a reducing agent into the reactor, wherein the regenerable low-temperature SCR De-NOx catalyst comprises: a carrier skeleton formed of a thermoplastic plastic; and a low-temperature SCR De-NOx catalytically active component complexed in and supported by the carrier skeleton; the fine SCR De-NOx catalyst system is configured to facilitate removal of an inactivated catalyst module and replacement of a new catalyst module and / or a regenerated catalyst module; wherein the regenerated catalyst module is a catalyst module obtained by regenerating and reloading the regenerable low-temperature SCR De-NOx catalyst after being taken out of the inactivated catalyst module; and the regenerable low-temperature SCR De-NOx catalyst is capable of being regenerated by reshaping of the carrier skeleton of the thermoplastic plastic.

[0036] According to one embodiment, a plurality of catalyst modules are arranged inside the reactor in multiple layers spaced apart from each other.

[0037] According to one embodiment, the shape of the carrier skeleton is selected from at least one of a flat plate, a corrugated plate, a honeycomb, a particle, a cloth, a tube, a rod, a mesh, and a porous sponge.

[0038] According to one embodiment, the carrier skeleton has a porous configuration.

[0039] According to one embodiment, the thermoplastic plastic is selected from at least one of PEEK, PFA, PPS, PTFE, PBT, PEI, PES, PCTFE, ETFE, PAI, PBI, PI, FEP, PPA, PSU, PPSU, PE, PP, fluoro rubber (FKM), silicone rubber (VMQ), and nylon (PA).

[0040] According to one embodiment, the carrier skeleton has a self-supporting configuration both before and after reshaping, whereby the regenerable low-temperature SCR De-NOx catalyst has a self-supporting configuration without the need for external support.

[0041] According to one embodiment, the reactor is provided with at least one of a homogenizer, a pressure equalization device, a flue gas temperature regulator, a temperature sensor, and a pressure sensor.

[0042] According to one embodiment, the spraying system comprises: a reducing agent spraying system for spraying a reducing agent or a reducing agent solution into the reactor; and a reducing agent supply and storage system for storing and delivering the reducing agent to the spraying system.

[0043] According to one embodiment, the low-temperature SCR catalyst has an operating temperature of 250°C or less.

[0044] According to an embodiment, the catalyst module is a segmented catalyst module comprising a plurality of catalyst module segments spaced apart from each other.

[0045] According to an embodiment, the plurality of catalyst module segments comprises at least two of a plate catalyst module segment, a honeycomb catalyst module segment and a pellet catalyst module segment.

[0046] According to an embodiment, the segmented catalyst module is arranged in the order of the plate catalyst module segment, the honeycomb catalyst module segment and the pellet catalyst module segment along the flue gas flow direction. In this order, as the flue gas flows through the plate catalyst module segment, the honeycomb catalyst module segment and the pellet catalyst module segment in sequence, due to the internal structure of the three catalyst module segments, the flow rate of the flue gas naturally and spontaneously decreases in this order, thereby effectively removing, in sequence, the nitrogen oxides (NOx) in the flue gas according to the three catalyst module segments, reducing the NOx content and achieving fine denitration in stages.

[0047] According to an embodiment, further comprising a control system for monitoring and / or adjusting the fine SCR denitration catalyst system reaction conditions.

[0048] According to an embodiment, the shape of the reshaped carrier skeleton is selected from at least one of a flat plate, a corrugated plate, a honeycomb, a pellet, a cloth, a tube, a rod, a mesh and a porous sponge.

[0049] According to an embodiment, the low-temperature SCR denitration catalytically active component comprises at least one of a Mn / Ce catalytic material, a V-based catalytic material or a Cu-based catalytic material.

[0050] According to an embodiment, the carrier skeleton has an internal porous structure.

[0051] According to an embodiment, the internal porous structure accounts for more than 10% of the volume percentage of the carrier skeleton.

[0052] According to an embodiment, the reshaping is thermoplastic molding.

[0053] According to an embodiment, the thermoplastic plastic suitable for thermoplastic molding is selected from at least one of PEEK, PFA, PPS, PTFE, PBT, PEI, PES, PCTFE, ETFE, PAI, PBI, PI, FEP, PPA, PSU, PPSU, PE, PP, fluororubber (FKM), silicone rubber (VMQ) and nylon (PA).

[0054] According to an embodiment, the reshaping is hot-press molding.

[0055] According to an embodiment, the thermoplastic suitable for hot press forming is selected from at least one of ETFE, PFA, FEP, PPS, PBT, PBI, PEI, PSU, PEEK, fluoro rubber (FKM), silicone rubber (VMQ) and nylon (PA).

[0056] According to an embodiment, the carrier skeleton has a self-supporting configuration before and after reshaping, thereby enabling the regenerable low-temperature SCR denitration catalyst to have a self-supporting configuration without external support.

[0057] According to an embodiment, a plurality of layers of catalyst modules are arranged inside the reactor and spaced apart from each other.

[0058] According to an embodiment, the reactor is configured with at least one of a homogenizer, a pressure balancing device, a flue gas temperature regulator, a temperature sensor and a pressure sensor.

[0059] According to an embodiment, the injection system comprises: a reducing agent injection system for injecting a reducing agent or a reducing agent solution into the reactor; and a reducing agent supply and storage system for storing and delivering the reducing agent to the injection system.

[0060] According to an embodiment, the low-temperature SCR catalyst has an operating temperature of 250°C or lower.

[0061] According to an embodiment, the low-temperature SCR catalyst further comprises a pore-forming agent and / or a foaming agent for forming an internal porous structure.

[0062] According to an embodiment, the internal porous structure accounts for 10% or more of the volume percentage of the carrier skeleton of the low-temperature SCR catalyst.

[0063] The application also discloses a low-temperature SCR catalytic denitration application of the above-mentioned fine SCR denitration catalyst system capable of reshaping and multiple regeneration in flue gas denitration of thermal power plants, incineration plants, cement plants and gas scrubbing equipment or exhaust gas treatment of internal combustion engine driven motor vehicles.

[0064] According to another aspect of the present application, there is provided a recycling method of a regenerable fine SCR De-NOx catalyst system, the regenerable fine SCR De-NOx catalyst system comprising: a catalyst module comprising a regenerable low-temperature SCR De-NOx catalyst, wherein the low-temperature SCR catalyst has an operating temperature of 300°C or lower; a reactor for accommodating the catalyst module; and a spray system for spraying a reducing agent into the reactor, the regenerable low-temperature SCR De-NOx catalyst comprising: a carrier framework formed of a thermoplastic plastic; and a low-temperature SCR De-NOx catalytically active component compounded in and supported by the carrier framework, the recycling method comprising: removing the deactivated catalyst module from the reactor; pre-treating the low-temperature SCR De-NOx catalyst of the deactivated catalyst module before regeneration; re-shaping the pre-treated low-temperature SCR De-NOx catalyst, wherein the regeneration of the low-temperature SCR De-NOx catalyst is achieved simultaneously with the re-shaping; and loading the regenerated low-temperature SCR De-NOx catalyst back into the catalyst module, and then re-loading the catalyst module back into the reactor, thereby achieving the recycling of the fine SCR De-NOx catalyst system.

[0065] According to an embodiment, the pre-treatment comprises the following steps: crushing the low-temperature SCR De-NOx catalyst of the deactivated catalyst module to obtain a regenerated powder within a desired size range. The low-temperature SCR De-NOx catalyst of the deactivated catalyst module is cleaned before or after the crushing. A screening process is performed after the crushing. At least one of a thermoplastic plastic powder and a low-temperature SCR De-NOx catalytically active component powder is added to the regenerated powder.

[0066] According to an embodiment, at least one of a pore-forming agent, a foaming agent, and a plasticizer is added to the regenerated powder.

[0067] According to an embodiment, the re-shaping of the regenerated powder is selected from at least one of the following processes: thermoforming, hot-pressing, extrusion, 3D printing, electrospinning, spray coating, injection molding, die molding, blow molding, calendering, rotational molding, suction molding, slush molding, casting, tape casting, foaming, transfer molding, and winding.

[0068] According to an embodiment, the re-shaping process of the regenerated powder is the same as the shaping process of the powder of the low-temperature SCR De-NOx catalyst before regeneration.

[0069] According to an embodiment, the finished shape of the re-shaped regenerated low-temperature SCR De-NOx catalyst is selected from at least one of the following: a flat plate, a corrugated plate, a honeycomb, a particle, a cloth, a tube, a rod, a mesh, and a porous sponge.

[0070] According to an embodiment, the finished shape of the re-shaping of the regenerated powder is the same as the shape of the low-temperature SCR De-NOx catalyst before regeneration.

[0071] According to another aspect of the present application, there is provided a low-temperature SCR catalyst capable of being reshaped for regeneration, comprising: a carrier skeleton of thermoplastic plastic, wherein the shape of the carrier skeleton of thermoplastic plastic is selected from at least one of the following: flat plate, corrugated plate, honeycomb, granular, cloth, tubular, rod, mesh and porous sponge; a low-temperature SCR catalyst active part compounded on or in the carrier skeleton and supported thereby; wherein the low-temperature SCR catalyst is capable of being regenerated by reshaping the carrier skeleton of thermoplastic plastic into one of the following shapes: flat plate, corrugated plate, honeycomb, granular, cloth, tubular, rod, mesh and porous sponge.

[0072] According to an embodiment, the low-temperature SCR catalyst active part comprises a low-temperature denitration catalytically active material.

[0073] According to an embodiment, the low-temperature denitration catalytically active material comprises at least one of Mn / Ce catalytic material, V-based catalytic material or Cu-based catalytic material.

[0074] According to an embodiment, the carrier skeleton has an internal porous structure.

[0075] According to an embodiment, the low-temperature SCR catalyst active part is compounded in the carrier skeleton in the form of dispersed particles.

[0076] According to an embodiment, the low-temperature SCR catalyst active part is compounded on the carrier skeleton in the form of a thin film.

[0077] According to an embodiment, the working temperature of the low-temperature SCR catalyst is below 300°C.

[0078] According to an embodiment, the carrier skeleton of the low-temperature SCR catalyst has a self-supporting configuration both before reshaping and after reshaping, thereby enabling the low-temperature SCR catalyst to have a self-supporting configuration without external support within a set working temperature range.

[0079] The present application overcomes many inherent technical defects of conventional technologies, including: overcoming the huge waste and high cost of catalyst modules caused by the easy deactivation, inability to be reshaped and regenerated of conventional catalysts / modules; the environmental negative impact and environmental pollution caused by the disposal of conventional catalysts / modules; overcoming the length, complexity and high cost of the conventional production process and steps of conventional catalysts / modules; the lightweight of the catalyst modules of the present application replacing the bulkiness of conventional catalysts / modules, reducing the difficulty of disassembly and transportation of conventional catalysts / modules, etc. BRIEF DESCRIPTION OF DRAWINGS

[0080] The above-described features and advantages of these embodiments, as well as other features and advantages, and the ways in which they are implemented, will become more apparent from the following description in conjunction with the accompanying drawings, and embodiments of this application can be better understood.

[0081] Figure 1A and Figure 1B These are, respectively, honeycomb catalyst products and granular catalyst products prepared by thermoplastic molding according to an embodiment of this application.

[0082] Figure 2A and Figure 2B These are three-dimensional schematic diagrams of industrial products of plastic honeycomb catalysts prepared by thermoplastic molding, for example, according to an embodiment of this application. Figure 2A ), and cross-sectional schematic diagram ( Figure 2B ),in Figure 2B The diagram schematically illustrates the presence of numerous pore structures in the flue gas channels of this thermoplastic honeycomb catalyst product.

[0083] Figure 3A A front view photograph of a plate-shaped catalyst product prepared by hot pressing according to an embodiment of this application is shown.

[0084] Figure 3B A perspective view of a thermoplastic plate catalyst product prepared by hot pressing according to an embodiment of this application is schematically shown.

[0085] Figure 3C schematically shown Figure 3A The image shown is an enlarged schematic of a single thermoplastic plate catalyst product, demonstrating the presence of numerous porous structures on the surface of the plate catalyst.

[0086] Figure 4 A schematic diagram of an activity evaluation apparatus for testing and evaluating the catalytic activity of the honeycomb low-temperature SCR catalyst of this application is shown.

[0087] Figure 5 This illustration schematically demonstrates a performance comparison between a PEEK-based catalyst prepared by thermoplastic molding according to an embodiment of this application and an industrial catalyst.

[0088] Figure 6 The illustration schematically shows a performance comparison between PEEK, PFA, and PPS-based catalysts prepared by thermoplastic molding according to an embodiment of this application and industrial catalysts.

[0089] Figure 7 The illustration schematically demonstrates a performance comparison of different plastic-based catalysts prepared by hot pressing according to an embodiment of this application.

[0090] Figure 8 Exemplary PEEK-based catalyst SO2 poisoning performance test results and PEEK-based catalyst performance test results after reforming of used deactivated PEEK-based catalyst according to an embodiment of the present application are shown schematically.

[0091] Figure 9 Data showing performance recovery of PEEK-based catalyst after SO2 poisoning and regeneration according to an embodiment of the present application is shown schematically.

[0092] Figure 10 Exemplary PEEK-based catalyst performance test results at predetermined reasonable operating temperatures after multiple reforming of PEEK-based catalyst according to an embodiment of the present application are shown schematically.

[0093] Figure 11 Exemplary thermoplastic forming process for preparing low temperature SCR catalyst according to an embodiment of the present application is shown schematically.

[0094] Figure 12 Exemplary fine SCR DeNOx catalyst system capable of multiple regeneration according to an embodiment of the present application is shown schematically for exemplarily showing and describing the segmented catalyst (module / segment) arrangement of the present application for fine SCR DeNOx and its general configuration. DETAILED DESCRIPTION

[0095] The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the application will be apparent from the description and drawings, and from the claims.

[0096] Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The application will be more fully understood and appreciated by

[0097] Generally speaking, the working principle of selective catalytic reduction (SCR) DeNOx catalysts involves mainly the following steps:

[0098] (i) External diffusion process: the process of diffusion of nitrogen oxides and ammonia from the gas phase bulk to the outer surface of the catalyst;

[0099] (ii) Internal diffusion process: diffusion of reactants from the outer surface to the inner surface of the catalyst, reaction at the active center;

[0100] (iii) Adsorption process: adsorption of reactants at the active center;

[0101] (iv) Catalytic reaction: at the catalyst active center and at a certain temperature, adsorbed nitrogen oxides (NO x) and ammonia gas to generate nitrogen and water;

[0102] (v) desorption process: reaction products are desorbed from active centers; and

[0103] (vi) internal diffusion process: after the reaction products are desorbed from the active centers, they diffuse from the inner surface to the outer surface of the catalyst.

[0104] Low-temperature SCR denitration systems generally include devices for storing and injecting a reducing agent such as ammonia NH3 or urea CO(NH2)2, an SCR control unit, and an SCR catalyst. Urea is hydrolyzed and decomposed to generate ammonia. At a suitable low-temperature condition (generally about 200-300°C or less), an ammonia-selective catalytic reduction (NH3-SCR) agent can directly catalyze the reaction of nitrogen oxides (NOx) in flue gas with ammonia to generate harmless nitrogen and water, while absorbing harmful flue gas particles. The corresponding reaction formula is as follows: x

[0105] CO(NH2)2+ H2O = CO2↑+ 2NH2↑

[0106] 4NH3+ 4NO + O2=> 4N2+ 6H2O

[0107] 4NH3+ 2NO2+ O2=> 3N2+ 6H2O

[0108] In terms of conventional technology, TiO2-based catalysts gradually replace Pt-Rh and Pt series catalysts. The composition of such catalysts has V2O5 as the main active component and WO3, MoO3 as the anti-oxidation and anti-poisoning auxiliary components, for example, mainly composed of V2O5(WO3), Fe2O3, CuO, CrO x , MnO x , MgO, MoO3, NiO, etc. metal oxides or mixed compounds for coordination, usually taking TiO2, Al2O3, ZrO2, SiO2, activated carbon (AC), etc. as carriers, and having a reducing reaction with liquid ammonia or urea reducing agent in the SCR system, becoming the mainstream catalyst product for power plant SCR denitration engineering applications.

[0109] ​The inventors of the present application have found that in the field of catalysts, polymer supported nano-catalytic particles as carrier materials can achieve rejuvenation and recycling, which makes it possible for nano-catalytic particles after service to be regenerated and reused in new or regenerated catalysts, and this recyclable feature makes it possible for the pollutants generated in the process of catalyst production not to flow back into the environment to cause pollution. The organic polymer carrier (or base, skeleton, etc.) of the catalyst, due to its small surface area, generally has a relatively low degree of active site exposure, so other aids need to be added to help generate a large number of pore structures to improve its specific surface area; in addition, this method accelerates the diffusion of water out of the catalyst, which helps to achieve high activity and long-term stability of the catalyst.

[0110] One of the main ideas of the present application is to preferably use a hydrophobic organic polymer, in particular a hydrophobic thermoplastic, as a carrier skeleton of a low-temperature SCR catalyst, which on the one hand can achieve the above technical advantages and can be technically applied to the application occasions of low-temperature SCR catalysts (here "low-temperature" refers to the normal working temperature of the SCR catalyst generally below 300°C, more preferably below 250°C), and on the other hand the thermoplasticity of such plastics makes it possible to realize the large-scale process method of reshaping and regeneration of the low-temperature SCR catalyst.

[0111] Of course, those skilled in the art can understand that using thermoplastic plastics (such as but not limited to PPS, PEEK, PBT, etc.) as low-temperature SCR catalyst carrier / base materials can achieve more technical advantages and benefits, including but not limited to: convenient cleaning, crushing processing and reshaping after sulfur (for example, SO2) poisoning and deactivation (ammonium sulfate salt deposition); can be conveniently used in a wide range of application environments including low ash areas, and is easy to clean and regenerate; the characteristics of thermoplastic plastics make the low-temperature SCR catalyst product lightweight, convenient to transport and install, and less brittle, not easy to be damaged during transportation, installation and use; wide availability, easy availability and low cost of the material; non-toxicity and environmental friendliness of the material; extremely high yield (theoretical yield 100%, no inferior products); extremely high recycling rate (theoretical recycling rate close to 100%).

[0112] The inventors of the present application have found that the carrier / base material suitable for low-temperature SCR catalysts can be selected to use thermoplastic plastic materials with relatively high plasticizing molding temperature (for example, the molding temperature thereof is generally above about 200°C) as carrier skeleton molding agents, such as but not limited to PBI; PI; TPI; PAI; PEEK; PPS; PTFE; PFA; ETFE; PCTFE, etc. The normal working temperature of such thermoplastic plastic-based "low-temperature" SCR catalyst is generally below 300°C, more preferably below 250°C.

[0113] The molding process of the thermoplastic plastic material in the preparation of the low-temperature SCR catalyst of the present application can include but is not limited to: thermoforming, hot-pressing molding, extrusion molding, 3D printing molding, electrospinning molding, spray molding, injection molding, die molding, blow molding, calendering molding, rotational molding, vacuum molding (blister molding), casting molding (injection molding), slush molding, flow casting molding, foaming molding, transfer molding (compression molding), winding molding, etc.

[0114] The shape (configuration) of the product molded after the preparation of the low-temperature SCR catalyst of the present application can include but is not limited to: honeycomb catalyst product, plate catalyst product, corrugated plate catalyst product, tubular catalyst product, rod catalyst product, granular catalyst product, mesh catalyst product, porous solid foam catalyst product, etc. According to the above concepts and features of the present application, these catalyst products can be remolded and regenerated after use.

[0115] According to the concept of one aspect of the present application, the thermoplastic molding of the low-temperature SCR catalyst of the present application can effectively perform rapid thermoplastic molding with polymeric thermoplastic plastic as the carrier material of the catalyst; the combination effect is better after adding catalyst powder (which can act as a binder), and the molding effect is better; the large number of pore structures generated during the thermoplastic process can make the molded catalyst have a larger specific surface area, thereby improving the catalytic activity; the performance of the catalyst is directly related to the content of the catalyst during the molding process, and the thermoplastic molded low-temperature SCR catalyst of the present application has a larger proportion of catalyst components, so its catalytic performance is better than that of existing catalysts under the same test conditions.

[0116] The thermoplastic polymer materials suitable for use in the thermoplastic molding and extrusion molding of the low-temperature SCR catalyst of the present application include: PEEK, PFA, PPS, PTFE, PBT, PEI, PES, PCTFE, ETFE, PAI, PBI, PI, FEP, PPA, PSU, PPSU, PE, PP, fluororubber (FKM), silicone rubber (VMQ), nylon (PA), etc. These materials are all polymer materials with rapid thermoplastic ability and stable physical and chemical properties.

[0117] In this embodiment, the catalyst powder used is selected from catalyst materials with good low-temperature denitration performance, such as: Mn / Ce low-temperature denitration catalyst, V-based catalyst, Cu-based catalyst, etc.

[0118] For detailed introduction and formula-related content of the Mn / Ce low-temperature denitration catalyst, please refer to the Chinese Invention Patent Application CN117019136A filed by the inventor of the present application on July 28, 2023. The relevant content of this Chinese Invention Patent Application is incorporated herein by reference.

[0119] Examples of low temperature SCR catalysts

[0120] Figure 1A and Figure 1B as well as Figure 2A and Figure 2B The illustration shows the catalyst product prepared by the thermoplastic molding method of this application. Among them, Figure 1A and Figure 1B These are, respectively, honeycomb catalyst products and granular catalyst products prepared by thermoplastic molding according to an embodiment of this application. Figure 2A and Figure 2B These are three-dimensional schematic diagrams of industrial products of plastic honeycomb catalysts prepared by thermoplastic molding, for example, according to an embodiment of this application. Figure 2A ), and cross-sectional schematic diagram ( Figure 2B ),in Figure 2B The illustration schematically demonstrates the presence of numerous pore structures within the flue gas channels of this thermoplastic honeycomb catalyst product, formed by the addition of a pore-forming agent. Those skilled in the art will understand that, as described above, the preparation of such low-temperature SCR catalysts (including but not limited to honeycomb structures) mentioned in this application can also be carried out using other molding processes disclosed in this application, and is not limited to thermoplastic molding.

[0121] Thermo plastic molding of low temperature SCR catalysts

[0122] Figure 11 The illustration shows an example of a thermoplastic molding process for preparing the low-temperature SCR catalyst of this application according to an embodiment of the present application.

[0123] The following uses PEEK material as an example, combined with the attached... Figure 11 As shown, the thermoplastic molding process of the low-temperature SCR catalyst of this application is further described.

[0124] 1) Mix 200-mesh Mn / Ce catalyst powder (8 parts by weight) with PEEK powder (20 parts by weight), add NaCl, CaSO4, (NH4)2CO3, carbon powder, etc. as pore-forming agents (10 parts by weight), mix thoroughly and place in a cylindrical stainless steel mold.

[0125] 2) Seal the stainless steel mold with a stainless steel press, place it in a muffle furnace and heat it at 300-320℃ and about 10.0MPa pressure for 6 hours to plasticize and form it.

[0126] 3) After water cooling, soak for 1-24 hours to remove the pore-forming agent, and dry to obtain a cake-shaped thermoplastic catalyst. Perform pore-drilling on a CNC machine tool to obtain a honeycomb-shaped low-temperature SCR catalyst product, for example... Figure 1A andFigure 2A and Figure 2B as shown.

[0127] Hot pressed molding of low temperature SCR catalysts

[0128] Figure 3A A front view photo of a plate catalyst product prepared by hot compression molding method according to an embodiment of the present application is shown. Figure 3B A perspective view schematic diagram of a thermoplastic plate catalyst product prepared by hot compression molding method according to an embodiment of the present application is shown schematically. Figure 3C A photo of a single thermoplastic plate catalyst of the thermoplastic plate catalyst product shown in Figure 3A

[0129] The thermoplastic polymer materials suitable for use in hot compression molding of the low temperature SCR catalyst of the present application include:

[0130] ETFE, PFA, FEP, PPS, PBT, PBI, PEI, PSU, PEEK, fluoro rubber (FKM), silicone rubber (VMQ), nylon (PA), etc. These polymer materials are selected to have suitable softening temperature, almost no flow in molten state, good surface wettability and stable physical and chemical properties.

[0131] Regeneration of low temperature SCR catalysts

[0132] An important inventive concept and key advantage of the present application is that the low temperature SCR catalyst of the present application can be conveniently regenerated by a re-molding process.

[0133] The process method for regeneration of the low temperature SCR catalyst of the present application is further introduced below by taking the PEEK-based low temperature SCR catalyst of the present application as an example.

[0134] 1) The deactivated (e.g. deactivated due to sulfur poisoning) PEEK-based thermoplastic molded catalyst is optionally first cleaned, for example, the surface fly ash and ammonium sulfate deposits are washed away by ultrasonic cleaning, dried and then put into a clean crusher for crushing treatment, for example, after crushing, the product is passed through a 10 mesh sieve to obtain a regenerated powder for re-molding.

[0135] 2) The above regenerated powder is mixed with a suitable proportion of pore-forming agent (see previous embodiments) and then placed in a mold.

[0136] ​The pore-forming agent is, for example, NaCl, CaSO4, (NH4)2CO3, carbon powder, etc., and the addition ratio is, for example, 10% to 150% by weight of the regenerated powder. The addition ratio of an example of the pore-forming agent, NaCl, is, for example, between 50% and 120% by weight of the regenerated powder.

[0137] 3) The mixed powder is added to a cylindrical mold, the mold is sealed with a press and placed in a muffle furnace for heating and thermoplastic forming, and the thermoplastic forming is performed at a heating temperature of 300 to 320°C and a pressure of 1 MPa to 5 MPa for 2 to 12 hours. If the particles of the regenerated powder are larger, the forming time of the remolding process step can be appropriately extended.

[0138] 4) After the thermoplastic forming, the mold is water-cooled / air-cooled for cooling, and after cooling to room temperature, the catalyst is taken out of the mold, water-cooled again, and after completely cooling to room temperature, it is taken out and transferred to a cleaning solution to wash away the pore-forming agent. The soaking time in the cleaning solution is 1 to 12 hours, and the cleaning solution can be one or more of ammonia, sodium bicarbonate, ammonium carbonate, and trisodium phosphate solution, and the solution PH value can be maintained at 5 to 8. After that, punching processing is performed on a numerical control machine tool to obtain a honeycomb-shaped low-temperature SCR catalyst.

[0139] In this regard, those skilled in the art can understand that in the above process step 1), a certain proportion of catalyst powder (for example, 10% of Mn / Ce powder) and / or PEEK powder can be selectively supplemented in the above regenerated powder to make up for possible composition and performance loss. Of course, this is not necessary, and test studies have shown that without supplementing catalyst and / or polymer powder, the low-temperature SCR catalyst of the present application can still be successfully remolded and regenerated without substantially affecting its catalytic performance. Experimental data show that the denitration efficiency of the low-temperature SCR catalyst of the present application after regeneration is comparable to that of existing industrial catalysts, and its activity can be maintained at least 80% or more, as described in detail below.

[0140] Those skilled in the art can understand that the above honeycomb-shaped low-temperature SCR catalyst can be remolded into other shapes as needed during remolding and regeneration, such as rod-shaped, pellet-shaped low-temperature SCR catalysts, etc., and it is not necessary to be remolded into a honeycomb-shaped low-temperature SCR catalyst.

[0141] Those skilled in the art can also understand that the reshaping and regeneration of the above low-temperature SCR catalyst can also be performed by other suitable and applicable process methods other than hot plastic molding and hot extrusion molding, such as but not limited to: hot extrusion molding, 3D printing molding, electrostatic spinning molding, spray molding, cold extrusion molding, die molding, blow molding, calender molding, rotational molding, vacuum molding (blister molding), casting molding (injection molding), slush molding, flow casting molding, foaming molding, press injection molding, winding molding, etc., which can be determined according to the material type of the thermoplastic plastic skeleton, the catalyst active ingredient and parameters, the shape of the required low-temperature SCR catalyst, the needs of the application, etc.

[0142] Fine SCR DeNOx catalyst system capable of multiple regeneration and operation thereof

[0143] Figure 12 An example of a fine SCR denitration catalyst system capable of multiple regeneration according to an embodiment of the present application is schematically shown for exemplarily showing and describing the system of the segmented catalyst (module / segment) arrangement of the present application for fine SCR denitration and its general configuration.

[0144] According to the present embodiment, a low-temperature selective catalytic reduction (SCR) system for flue gas denitration is introduced, which contains the low-temperature SCR catalyst of the present application, such as the catalyst module prepared by hot plastic molding and extrusion molding process.

[0145] The fine SCR denitration catalyst system of the present application has better performance in the molding process, catalytic activity and mechanical strength of the low-temperature SCR catalyst, such as providing higher catalytic activity and better mechanical strength.

[0146] In the present embodiment, the fine SCR denitration catalyst system can be composed of several main parts:

[0147] (1) Catalyst module suitable for replacement: can contain a plurality of (such as multiple layers) regenerated low-temperature SCR denitration catalyst products of the present application, such as plate-shaped, honeycomb-shaped and / or granular catalysts spaced apart from each other, for providing a segmented / staged low-temperature SCR denitration process, such as below 300°C.

[0148] Preferably, as introduced above, the regenerable low-temperature SCR De-NOx catalyst can include: a thermoplastic plastic formed carrier skeleton; a low-temperature SCR De-NOx catalytically active component compounded in and supported by the carrier skeleton. The fine SCR De-NOx catalyst system is configured to facilitate the removal of the deactivated catalyst module and the replacement of a new catalyst module and / or a regenerated catalyst module, which is a catalyst module obtained by regenerating and reloading the regenerable low-temperature SCR De-NOx catalyst taken out from the deactivated catalyst module after the regeneration of the regenerable low-temperature SCR De-NOx catalyst capable of being regenerated by reshaping the thermoplastic plastic carrier skeleton.

[0149] For example, the plurality of catalyst module segments includes at least two of a plate catalyst module segment, a honeycomb catalyst module segment, and a pellet catalyst module segment.

[0150] According to a preferred example, the segmented catalyst module is arranged in the order of the plate catalyst module segment, the honeycomb catalyst module segment, and the pellet catalyst module segment along the direction of the flue gas flow. In this order, as the flue gas flows through the plate catalyst module segment, the honeycomb catalyst module segment, and the pellet catalyst module segment in turn, due to the internal structure of the three catalyst module segments, the flow rate of the flue gas naturally and spontaneously decreases in this order, thereby effectively removing, in turn, step by step, the nitrogen oxides (NOx) in the flue gas according to the three catalyst module segments, for example, by reducing the content of NOx, to achieve fine De-NOx. x x

[0151] (2) Reactor: for accommodating the catalyst module and providing a suitable SCR De-NOx reaction environment.

[0152] The reactor can generally be made of stainless steel (such as 316L or 304) or carbon steel (surface coated with high-temperature resistant anticorrosive coating) and have a cylindrical or cuboid shape with specific dimensions designed according to the flue gas treatment capacity (for example, diameter 2-5 meters, length 5-15 meters). The reactor can be internally provided with multiple layers of catalyst modules (for example, arranged in the order of plate catalyst module, honeycomb catalyst module, and pellet according to the direction of flue gas flow), and the thickness of the catalyst layer can be 300-500 mm or more, and the layer spacing can be 50-100 mm to optimize airflow distribution and reaction efficiency. A homogenizer (such as a flow guide plate or a static mixer) can be configured at the inlet of the reactor to ensure uniform mixing of the flue gas and ammonia gas, and a pressure balancing device can be provided at the outlet to avoid airflow disturbance.

[0153] The reactor can be equipped with a flue gas temperature regulation system (such as a heat exchanger or a heater) to maintain the reaction temperature in the range of, for example, 200-300°C to meet the needs of low-temperature SCR catalysts.

[0154] ​​The reactor can be equipped with temperature sensors (e.g., thermocouples or infrared thermometers) and pressure sensors to monitor the operating conditions in real time and automatically adjust through the control system.

[0155] For example, commercially available reactors include the SCR-EE-LA / UR type produced by Hebei Chengyue Environmental Engineering Co., Ltd., which supports low-temperature denitrification and is designed in a modular manner suitable for boiler flue gas treatment; the double-path vertically arranged reactor produced by Shandong Shoufeng Intelligent Environmental Protection Equipment Co., Ltd., which can be applied to various dust flue gas conditions; the honeycomb catalyst integrated reactor provided by Yuanchen Environmental Protection Technology Co., Ltd., etc.

[0156] (3) Injection system: used to inject reducing agents (e.g., ammonia water or urea solution) into the reactor.

[0157] The injection system can generally include:

[0158] The ammonia / ammonia water injection system can use stainless steel (e.g., 316L) or ceramic nozzles, and the structure can be a multi-hole atomizing type or a fan-shaped injection type with a pore size of 0.5-2 mm and an adjustable injection angle of 30-90° to ensure sufficient mixing of ammonia gas and flue gas. The nozzles can be evenly distributed along the flue cross-section with a spacing of, for example, 200-500 mm, and the injection direction can be arranged in counterflow or co-flow with the flue gas flow direction to enhance the mixing effect. The injection pressure and flow rate of ammonia / ammonia water: working pressure 0.3-0.8 MPa, flow rate range 50-500 L / min (which can be adjusted according to the NOx concentration of the flue gas). x Dynamic adjustment); and

[0159] The ammonia supply and storage system can include a storage tank and a conveying device. The storage tank can be, for example, a stainless steel tank with a volume of 10-50 m 3 , equipped with a liquid level gauge, a safety valve, and a leak detection device, and designed with a pressure of 1.5 MPa. The conveying device can use, for example, a corrosion-resistant centrifugal pump (e.g., Grundfos CR series) or a screw pump with a flow accuracy of ±2% and supporting PLC remote control.

[0160] Examples of commercially available injection systems include, for example, the SNCR-EE-LA / UR type provided by Hebei Chengyue Environmental Engineering Co., Ltd., equipped with high-pressure atomizing nozzles and a redundant safety system; the "double-path ammonia injection system" of Shandong Shoufeng Intelligent Environmental Protection Equipment Co., Ltd. (adapted for high-dust flue gas), etc., which can integrate a steam carrier gas device to enhance penetration.

[0161] (4) Optional control system: used to monitor and / or adjust the SCR reaction conditions, such as temperature, pressure, and reducing agent injection amount, etc.

[0162] The control system can be used as a component of the fine SCR De-NOx catalyst system, or integrated into the control system of the application site or equipment of the fine SCR De-NOx catalyst system, such as a factory, a workshop, a waste gas treatment section, a ship, a car, etc.

[0163] As an example, the control system can be an automation system based on PLC (such as Siemens S7-1200), integrated with an ammonia flow meter (such as a mass flow meter), a NOx concentration sensor (such as an ultraviolet analyzer), and a temperature feedback module, to achieve closed-loop control of the ammonia-to-NOx molar ratio (NH3 / NOx, target value 0.8-1.2). In addition, an ammonia shut-off valve (such as an ASCO solenoid valve) can be triggered in an emergency, with a response time <1 second. x As an example, the control system can be an automation system based on PLC (such as Siemens S7-1200), integrated with an ammonia flow meter (such as a mass flow meter), a NOx concentration sensor (such as an ultraviolet analyzer), and a temperature feedback module, to achieve closed-loop control of the ammonia-to-NOx molar ratio (NH3 / NOx, target value 0.8-1.2). In addition, an ammonia shut-off valve (such as an ASCO solenoid valve) can be triggered in an emergency, with a response time <1 second. x

[0164] In this embodiment, the general operation of the fine SCR De-NOx catalyst system is as follows:

[0165] (1) System startup: After the system is started, the control system can automatically or manually adjust the reaction condition parameters in the reactor, such as the reaction temperature, pressure, and reducing agent injection amount, etc., according to the flue gas conditions.

[0166] (2) SCR catalytic De-NOx reaction: The injection system injects reducing agent into the reactor, which reacts with NOx in the flue gas on the surface of the low-temperature SCR De-NOx catalyst of the present application to generate nitrogen and water.

[0167] (3) Monitoring and adjustment: The control system monitors the reaction efficiency in real time, and adjusts the reaction conditions such as the reaction temperature, pressure, reducing agent injection amount, and / or reaction time, etc. as needed.

[0168] (4) Regeneration of the fine SCR De-NOx catalyst system: After a period of time or a predetermined service period, the low-temperature SCR De-NOx catalyst product is removed from the catalyst module, and the low-temperature SCR De-NOx catalyst is subjected to the reshaping regeneration treatment according to the regeneration method of the present application (for example, the regeneration of the low-temperature SCR catalyst is described above), and the regenerated low-temperature SCR catalyst is reinstalled into the catalyst module, thereby completing the regeneration of the fine SCR De-NOx catalyst system. Thus, the regenerated fine SCR De-NOx catalyst system can be reused and used normally.

[0169] More specifically, according to an example, the recycling method of the fine SCR De-NOx catalyst system capable of multiple regenerations can include the following steps:

[0170] removing the deactivated catalyst module from the reactor;

[0171] pre-treating the low-temperature SCR De-NOx catalyst of the deactivated catalyst module before regeneration; ​

[0172] The pre-processed low-temperature SCR denitration catalyst can be re-shaped, and the regeneration of the low-temperature SCR denitration catalyst can be realized at the same time of re-shaping;

[0173] The regenerated low-temperature SCR denitration catalyst is loaded back into the catalyst module, and then the catalyst module is reloaded into the reactor, thereby realizing the recycling use of the fine SCR denitration catalyst system.

[0174] The pre-treatment can include the following steps: crushing the low-temperature SCR denitration catalyst of the deactivated catalyst module to obtain regenerated powder in a desired size range. Before or after the crushing treatment, the low-temperature SCR denitration catalyst of the deactivated catalyst module can be cleaned. After the crushing treatment, a screening treatment can also be performed.

[0175] The regenerable fine SCR denitration catalyst system of the embodiment adopts the re-shapeable and regenerated low-temperature SCR denitration catalyst of the application, has lower cost, very simple and efficient re-shaping and regeneration process, almost 100% regenerability, almost no loss of catalytic activity, and better mechanical strength than existing catalyst products, can be effectively recycled for reducing NOx emissions in flue gas, reducing energy consumption, reducing pollution, reducing waste, re-shaping and recycling, low maintenance cost, light weight of catalyst (module) and convenient installation and transportation, etc., and meets strict environmental protection and regulatory requirements. x

[0176] Testing and evaluation of low temperature SCR catalysts

[0177] Figure 4 A schematic diagram of an activity evaluation device for testing and evaluating the catalytic activity of the honeycomb low-temperature SCR catalyst of the application is schematically shown. Through the activity evaluation device, the catalytic activity of the honeycomb low-temperature SCR catalyst of the application, such as MnO x / CeO2 catalyst composition, can be tested and evaluated, wherein the reaction gas can be mixed in the gas mixing tank via the mass flow meter to control the gas flow, and after the catalytic reaction treatment of the low-temperature SCR catalyst of the application, the flue gas NOx content can be tested at the tail gas end. x

[0178] Figure 5 The performance comparison between the PEEK catalyst prepared by the thermoforming method according to an embodiment of the application (i.e., the PEEK-based low-temperature SCR catalyst of the application) and the industrial catalyst is schematically shown. In the test, the test carrier gas is N2, the gas flow rate is 2.1 m / s, NO: 500 ppm, NH3: 500 ppm, O2: 5%, and the volume space velocity GHSV is 6000 h -1 ​​The test is the performance test result of the catalytic activity of the PEEK catalyst, the industrial small-scale catalyst and the industrial catalyst under the same size and the same test condition. The test result shows that the low-temperature SCR catalyst prepared by taking the PEEK plastic as the carrier material has higher catalytic activity and is close to the performance of the industrial catalyst.

[0179] Figure 6 The performance comparison of the PEEK, PFA and PPS-based catalysts prepared by the thermoforming method according to an embodiment of the application and the industrial catalyst is schematically shown. In the test, the carrier gas is N2, the gas flow rate is 2.1 m / s, NO is 500 ppm, NH3 is 500 ppm, O2 is 5%, the volume space velocity GHSV is 6000 h-1, and the temperature is 150-200℃. -1 The test is the performance test result of the catalysts prepared by thermoforming different materials under the same size and the same test condition, and the industrial catalyst. The content in the brackets after the material indicates the mass ratio of the active component of the catalyst in the carrier material. It can be seen that the catalytic performance of the formed catalyst prepared by taking the PEEK and PFA materials as the base materials is almost the same as that of the industrial catalyst in the temperature range of 150-200℃.

[0180] Figure 7 The performance comparison of the different plastic-based catalysts prepared by the thermoforming method according to an embodiment of the application is schematically shown. In the test, the carrier gas is N2, the gas flow rate is 2.1 m / s, NO is 500 ppm, NH3 is 500 ppm, O2 is 5%, the volume space velocity GHSV is 1500 h-1, and the temperature is 150-200℃. -1 The performance of the plate catalyst product of the application prepared according to three different catalyst skeleton materials is close to the performance of the industrial catalyst.

[0181] Figure 8 The SO2 poisoning performance test of the PEEK-based catalyst according to an embodiment of the application and the SO2 poisoning performance test result of the PEEK-based catalyst remolded after use are schematically shown. In the test, the carrier gas is N2, the gas flow rate is 2.1 m / s, NO is 500 ppm, NH3 is 500 ppm, O2 is 5%, SO2 is 200 ppm, the volume space velocity GHSV is 9000 h-1, and the temperature is 150-200℃. -1In this comparative experiment, the performance of the shaped catalyst prepared with PEEK material was tested under a higher SO2 concentration of 200 ppm. The catalyst activity decreased slightly within 24 h but stabilized at about 80% and did not change any more. After 24 h of testing, the catalyst was taken out and reshaped. The reshaped catalyst was subjected to the same anti-poisoning experiment. The results showed that the catalyst performance remained above 80% and did not decrease in the next 24 h of SO2 poisoning test. This indicates that the reshaping process does not affect the catalyst activity.

[0182] Figure 9 The data of performance recovery of the PEEK-based catalyst after SO2 poisoning and regeneration according to an embodiment of the present application are schematically shown.

[0183] Figure 10 The performance test results of the PEEK-based catalyst after multiple reshaping and working at a predetermined reasonable working temperature according to an embodiment of the present application are schematically shown. A small amount of broken powder is inevitably lost during the reshaping process. Therefore, catalyst powder or thermoplastic powder can be appropriately added during the reshaping process to make the size of the reshaped catalyst and the size before breaking basically consistent. In general, the amount added is preferably less than about 30% of the total catalyst amount before breaking. Excessive amount of active component will result in a smaller specific gravity of the thermoplastic material, a weak bonding effect between the active components, and difficulty in shaping.

[0184] Introduction of some technical effects of low temperature SCR catalysts

[0185] In the technical content of the present application, the thermoplastic material can be used as a carrier (or matrix, skeleton, carrier skeleton, etc.) material of the catalyst to replace the existing TiO2 and other conventional materials, thereby simplifying the integrated shaping process of the catalyst and the regeneration process (such as through reshaping) of the catalyst. The polymer thermoplastic is used as a carrier material, and the catalyst powder is used as an inorganic binder of the thermoplastic, so that the two are tightly combined during the thermoplastic shaping process, improving the mechanical strength of the overall catalyst and avoiding the leaching of the active component of the catalyst. The addition of the pore-forming agent enables the monolithic catalyst to have more fine pore structures during preparation, thereby improving the specific surface area of the catalyst. The use of thermoplastic as a base material enables the catalyst to be reused, and the regeneration process is simple and fast, which can avoid energy waste and environmental pollution in the traditional regeneration process, and greatly prolongs the service life of the catalyst.

[0186] The application is proved by experiments that the catalyst prepared by the preferred formula of the application has similar denitration activity to traditional industrial catalysts under the same size and the same test conditions at 200℃, 150℃ and 100℃; under the preferred catalyst formula of the application, the performance of the catalyst remains above 80% without decline under long-time continuous operation at 200ppm SO2; after cleaning and reshaping of the poisoned catalyst by the regeneration method introduced in the application, the activity of the catalyst remains basically the same as the performance before reshaping under the tests at 200℃, 150℃ and 100℃; after multiple reshaping of the catalyst by the regeneration method introduced in the application, the activity of the catalyst remains basically the same as the performance before the first reshaping under the tests at 200℃, 150℃ and 100℃.

[0187] The foregoing description of the embodiments of the application is presented for purposes of illustration. It is understood that the scope of the application is defined by the appended claims.

Claims

1. A fine SCR De-NOx catalyst system which is capable of being regenerated multiple times, characterized by, Comprising: a catalyst module configured to be replaceable, which contains a low-temperature SCR denitration catalyst capable of being regenerated by reshaping for multiple passes, wherein the low-temperature SCR catalyst has an operating temperature of 300℃ or lower; a reactor for accommodating the catalyst module; and a spray system for spraying a reducing agent into the reactor, wherein the low-temperature SCR denitration catalyst capable of being regenerated by reshaping for multiple passes comprises: a carrier skeleton formed of a thermoplastic plastic; and a low-temperature SCR denitration catalytically active component compounded in and supported by the carrier skeleton; and wherein the fine SCR denitration catalyst system is rapidly regenerated and recycled by removing the deactivated catalyst module and replacing it with a new catalyst module or a regenerated catalyst module; and wherein the regenerated catalyst module is obtained by reshaping and regenerating the low-temperature SCR denitration catalyst in the deactivated catalyst module; and wherein the low-temperature SCR denitration catalyst capable of being regenerated is capable of being regenerated by reshaping of the carrier skeleton of the thermoplastic plastic.

2. The fine SCR De-NOx catalyst system according to claim 1, characterized by, The catalyst module is a segmented catalyst module comprising a plurality of catalyst module segments spaced apart from each other.

3. The fine SCR DeNOx catalyst system according to claim 2, characterized in that, The plurality of catalyst module segments comprises at least two of a plate catalyst module segment, a honeycomb catalyst module segment, and a pellet catalyst module segment.

4. The fine SCR De-NOx catalyst system according to claim 3, characterized by The segmented catalyst module arranges the plate catalyst module segment, the honeycomb catalyst module segment, and the pellet catalyst module segment in sequence along a flue gas flow direction.

5. The fine SCR deNOx catalyst system of claim 1, wherein, Further comprising a control system for monitoring and / or adjusting reaction conditions of the fine SCR denitration catalyst system.

6. The fine SCR deNOx catalyst system of claim 1, wherein, The carrier skeleton has a shape selected from at least one of a flat plate, a corrugated plate, a honeycomb, a particle, a cloth, a tube, a rod, a mesh, and a porous sponge.

7. The fine SCR DeNOx catalyst system of claim 6, wherein, The reshaped carrier skeleton has a shape selected from at least one of a flat plate, a corrugated plate, a honeycomb, a particle, a cloth, a tube, a rod, a mesh, and a porous sponge.

8. The fine SCR DeNOx catalyst system of claim 1, wherein, The low-temperature SCR denitration catalytically active component comprises at least one of a Mn / Ce-based catalytic material, a V-based catalytic material, or a Cu-based catalytic material.

9. The fine SCR deNOx catalyst system of claim 1, wherein, The carrier skeleton can have an internal porous structure.

10. The fine SCR DeNOx catalyst system of claim 9, wherein, The internal porous structure accounts for 10% or more of the volume percentage of the carrier skeleton.

11. The fine SCR DeNOx catalyst system according to any one of claims 1 to 10, characterized in that, The reshaping is thermoplastic forming.

12. The fine SCR DeNOx catalyst system of claim 11, wherein, The thermoplastic plastic suitable for thermoplastic forming is selected from at least one of PEEK, PFA, PPS, PTFE, PBT, PEI, PES, PCTFE, ETFE, PAI, PBI, PI, FEP, PPA, PSU, PPSU, PE, PP, fluororubber (FKM), silicone rubber (VMQ), and nylon (PA).

13. The fine SCR DeNOx catalyst system according to any one of claims 1 to 10, characterized in that, The reshaping is hot-press forming.

14. The fine SCR DeNOx catalyst system of claim 13, wherein, The thermoplastic plastic suitable for hot-press forming is selected from at least one of ETFE, PFA, FEP, PPS, PBT, PBI, PEI, PSU, PEEK, fluororubber (FKM), silicone rubber (VMQ), and nylon (PA).

15. The fine SCR deNOx catalyst system of any one of claims 1-10, wherein, The carrier skeleton has a self-supporting configuration before and after the reshaping, thereby making the regenerable low-temperature SCR denitration catalyst have a self-supporting configuration without external support.

16. The fine SCR deNOx catalyst system of any one of claims 1-10, wherein, The reactor is arranged with multiple layers of the catalyst modules spaced apart from each other inside the reactor.

17. The fine SCR deNOx catalyst system of any one of claims 1-10, wherein, The reactor is configured with at least one of a homogenizer, a pressure balancing device, a flue gas temperature regulator, a temperature sensor, and a pressure sensor.

18. The fine SCR de-NOx catalyst system according to any one of claims 1 to 10, characterized in that, The injection system comprises a reducing agent injection system for injecting a reducing agent or a reducing agent solution into the reactor; and a reducing agent supply and storage system for storing and delivering the reducing agent to the injection system.

19. The fine SCR deNOx catalyst system of any one of claims 1-10, wherein, The low-temperature SCR catalyst has an operating temperature of 250°C or below.

20. The fine SCR deNOx catalyst system of claim 9 or 10, wherein, The low-temperature SCR catalyst can further comprise a pore-forming agent and / or a foaming agent for forming the internal porous structure.

21. The fine SCR de-NOx catalyst system of claim 20, wherein, The internal porous structure accounts for 10% or more of the volume percentage of the carrier skeleton of the low-temperature SCR catalyst.

22. Use of the regenerable fine SCR denitration catalyst system according to any one of claims 1-21 for low-temperature SCR catalytic denitration in flue gas denitration of thermal power plants, incineration plants, cement plants, and gas scrubbing equipment, or exhaust gas treatment of internal combustion engine driven motor vehicles.

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