A modified catalyst for resisting chloride ion poisoning and its preparation method

Abstract

This invention relates to the field of catalyst technology, and discloses a modified catalyst resistant to chloride ion poisoning and its preparation method. The catalyst has sacrificial sites configured in the nano-adjacent region of the catalytically active metal site and remote curing sites set in the distant region. A low-temperature ion transport channel is constructed between the two through a solid ion conductor. The core of this invention is that a closed-loop protection mechanism is established inside the catalyst, which combines targeted capture of poison, low-temperature transport and remote curing. This decouples the homology between the high activity of the catalyst and its vulnerability to chloride, enabling the catalyst to achieve long-term stable operation throughout the complete industrial operation cycle, including low-temperature start-up.

Description

Technical Field

[0001] This invention relates to a modified catalyst resistant to chloride ion poisoning and its preparation method, belonging to the field of catalyst technology. Background Technology

[0002] Currently, in many key chemical synthesis processes, such as the production of high-value-added chemicals from syngas, the use of supported noble metal or transition metal catalysts to achieve efficient conversion has become a common technical strategy in the industry. This is because the specific metal active sites exposed by these catalysts have the optimal electronic structure required to achieve the target reaction, which is the basis for ensuring high reactivity and selectivity. However, in engineering practice, a long-standing and difficult-to-reconcile fundamental constraint is that the catalytic activity of a catalyst is often negatively correlated with its tolerance to impurities. In particular, for electrophilic species such as chloride ions, the electronic state that endows the metal site with high catalytic activity also makes it exhibit a very strong chemical adsorption affinity for chloride ions. This means that the high efficiency and fragility of a catalyst are essentially of the same origin in physicochemical terms.

[0003] This inherent contradiction makes the problem particularly prominent when the source of raw materials expands from high-purity gases to more economical coke oven gas or biomass gasification syngas. These inexpensive raw materials generally contain trace amounts of persistent chlorides, which are enough to cause irreversible poisoning to the aforementioned high-performance catalysts in a short period of time. To address this challenge, the industry's common practice is to build a complex and expensive dechlorination and purification system upstream of the catalytic reactor, that is, to create a pure operating environment for the fragile catalyst through physical isolation. While this approach can ensure the operation of the catalyst, it also locks its own economics and versatility at a very high cost level, thereby weakening the original intention of using inexpensive raw materials.

[0004] To address this, the industry has attempted to develop catalysts with better tolerance, but the usual result is that improved tolerance often comes at the cost of catalytic activity, reverting to the old trade-off of sacrificing production efficiency for system lifespan. Specifically, existing technologies suffer from the following shortcomings: 1. Catalyst activity and resistance to toxicity are mutually restrictive; high-performance metal catalysts cannot operate stably directly in chlorine-containing environments. 2. Reliance on external purification systems for physical isolation results in high system investment and operating costs, limiting the economical utilization of large quantities of low-cost chlorine-containing feedstocks. 3. Existing technological approaches have failed to address the inherent vulnerability of active sites to chloride ions by addressing the catalyst's own structure. Therefore, the technical problem this invention aims to solve is how to construct a catalyst system that, while maintaining high catalytic activity, no longer relies on external extreme purification but instead resolves the poisoning threat posed by chloride ions entering the catalyst microenvironment through its internal synergistic mechanism. Summary of the Invention

[0005] This invention provides a modified catalyst resistant to chloride ion poisoning and its preparation method. Its main purpose is to solve the problem that existing high-performance catalysts are inherently vulnerable to chloride ions at their active sites, resulting in a mismatch between their high catalytic activity and resistance to chloride poisoning, thus requiring expensive external purification systems.

[0006] To achieve the above objectives, the present invention provides a modified catalyst for resisting chloride ion poisoning, the catalyst comprising a porous support and the following components dispersed on the porous support:

[0007] Catalytically active metal sites;

[0008] The sacrificial site and the catalytically active metal site are distributed adjacent to each other at the nanoscale, and the chemical reaction rate between the sacrificial site and chloride ions is higher than that between the catalytically active metal site and chloride ions.

[0009] Remote curing agent sites are spatially farther away from catalytically active metal sites than sacrificial agent sites.

[0010] The solid ion conductor component forms an ion transport channel that at least partially connects the sacrificial agent site and the remote curing agent site within the microstructure of the porous carrier.

[0011] The ion transport channel captures chloride ions at the sacrificial site, forming a chlorine-containing intermediate species. Under conditions below the threshold temperature at which the chlorine-containing intermediate species undergoes substantial thermal migration, the intermediate species migrates from the sacrificial site to the remote curing agent site and is then chemically reacted with the remote curing agent site to be cured.

[0012] Preferably, the catalyst is obtained by a preparation method comprising the following steps: first, loading a precursor of a solid ion conductor component onto a porous support to form an ion conductor network; second, loading a precursor of a remote curing agent site onto a porous support loaded with the ion conductor network; third, co-impregnating and loading a precursor of a catalytically active metal site and a precursor of a sacrificial agent site onto the porous support after the second step treatment; and fourth, calcining the porous support after the third step treatment.

[0013] Preferably, a method for online diagnosis of the remaining amount of sacrificial sites in the catalyst is provided, the method comprising the steps of: introducing a fluid pulse containing probe molecules into a feed stream in contact with the catalyst, the probe molecules undergoing a characteristic endothermic reaction at the sacrificial sites; measuring a temporary decrease in the catalyst bed outlet temperature caused by the characteristic endothermic reaction; and calculating a ratio of the maximum value of the temporary decrease in temperature measured at the current operating time to the maximum value of the temporary decrease in temperature measured at the catalyst under initial operating conditions, the ratio representing the remaining amount of sacrificial sites.

[0014] Preferably, the measurement further includes measuring the dynamic morphological characteristics of the response curve of the temporary decrease in temperature over time, the dynamic morphological characteristics including the peak width and response delay time of the response curve; the method further includes identifying the spatial consumption distribution pattern of sacrificial agent sites based on the dynamic morphological characteristics of the response curve; when the integral area of ​​the response curve decreases and the changes in its peak width and response delay time are within a first predetermined range, it is identified as a chronic uniform poisoning pattern; and when the integral area of ​​the response curve decreases, the decrease in its peak width exceeds a second predetermined threshold, and the increase in its response delay time exceeds a third predetermined threshold, it is identified as an acute local poisoning pattern.

[0015] Preferably, the sacrificial site comprises at least one selected from alkaline earth metal oxides and rare earth metal oxides.

[0016] Preferably, the sacrificial site is lanthanum oxide.

[0017] Preferably, the catalytically active metal site comprises at least one selected from platinum, palladium, rhodium, nickel, and cobalt.

[0018] Preferably, the remote curing agent site comprises at least one selected from alkali metal oxides, alkaline earth metal oxides, alkali metal carbonates and alkaline earth metal carbonates, and the solid ionic conductor component comprises a mesoporous zeolite or a supported solid superacid with proton acidity.

[0019] Preferably, the porous support is alumina, silica, or mesoporous molecular sieve.

[0020] A method for preparing a modified catalyst resistant to chloride ion poisoning, comprising the following steps:

[0021] Step a: Load the precursor of the solid ionic conductor component onto a porous support to form an ionic conductor network;

[0022] Step b: Load the precursor of the remote curing agent site onto a porous support loaded with an ion conductor network;

[0023] Step c: The precursors of the catalytically active metal sites and the precursors of the sacrificial sites are co-impregnated and loaded onto the porous support after the aforementioned steps.

[0024] Step d involves calcining the porous carrier after co-impregnation and loading.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention provides a method for synergistic internal function of a catalyst. By configuring sacrificial sites with higher chemical reaction priority for chloride ions in the nanoscale adjacent region of the catalytically active metal site, chloride ions in the feed stream are preferentially captured and chemically transformed by the sacrificial sites before diffusing to the catalytically active center. This process reconstructs the reaction pathway of chloride ions at the microscale, allowing the two mutually restrictive properties of high catalytic activity and tolerance to chloride-containing impurities to coexist, thereby changing the dependence of such catalysts on the degree of feed purification.

[0027] 2. This invention also provides a mechanism for dealing with sudden fluctuations in chloride ion concentration in raw materials. It constructs spatially separated sacrificial agent sites and remote curing agent sites in the catalyst structure. When a high concentration of chloride ions impacts and causes the sacrificial agent site to form a chloride-containing intermediate species, the intermediate species will migrate from the vicinity of the catalytic active center to the remote curing agent site under the drive of the reaction temperature, and undergo a further, more stable chemical curing reaction with it. This process not only removes the poison from the core functional area, but also allows the sacrificial agent site near the active center to restore its buffering and capturing capacity for subsequent chloride ions, so that the catalyst as a whole can maintain the integrity of its structure and function after being subjected to impurity impacts far exceeding the steady state level.

[0028] 3. This invention provides a method for online determination of the remaining amount of sacrificial agent by reusing the function of catalyst components. When needed, this method introduces a specific probe molecular fluid pulse into the feed gas. This probe molecule is selected to undergo a measurable characteristic endothermic reaction only at sacrificial agent sites in the effective state, while no reaction or negligible reaction occurs at catalytically active sites and deactivated sacrificial agent sites. Therefore, by monitoring the temperature change at the catalyst bed outlet, the invisible chemical state of the internal sacrificial agent can be transformed into an externally measurable physical signal directly related to the remaining amount, providing operators with a direct decision-making basis for judging the remaining protective capacity of the catalyst and the replacement cycle.

[0029] 4. The judgment method of this invention can also provide in-depth information about the consumption mode of the sacrificial agent. Due to the two different processes of chronic uniform poisoning and acute local poisoning, there will be differences in the spatial distribution of effective sacrificial agent sites in the bed. This will directly affect the reaction time and the centroid position of the reaction area when the probe molecule pulse flows through the bed, and will ultimately be reflected in the dynamic morphological characteristics such as the peak width and response delay of the outlet temperature response signal. Therefore, by parallel analysis of the signal morphology, the type of aging process that the catalyst is undergoing can be distinguished, providing process-level information support for fault diagnosis and preventive maintenance of upstream processes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the internal synergistic protection mechanism of the catalyst in this invention;

[0031] Figure 2 This is a comparison of the outlet temperature response curves of the online diagnostic method of the present invention under different poisoning modes;

[0032] Figure 3 This is a logic flowchart of the online diagnostic method of the present invention;

[0033] Figure 4 This is a schematic diagram of the microstructure of the chloride ion poisoning resistant modified catalyst of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. However, those skilled in the art will understand that various modifications or equivalent substitutions can be made to the specific embodiments described herein without departing from the spirit and scope of the present invention, and all such modifications and equivalent substitutions fall within the protection scope of the appended claims.

[0035] This invention provides a modified catalyst for resisting chloride ion poisoning and its preparation method. The catalyst contains a protective mechanism comprised of sacrificial sites, remote curing agent sites, and a solid ion conductor component working synergistically. This mechanism enables targeted capture, low-temperature transport, and remote curing of chloride species. Furthermore, it allows for the establishment of an online diagnostic method for its protective capabilities and health status by utilizing the functional properties of its components. The catalyst system mainly comprises a porous support, and four functional units dispersed and loaded on the porous support: catalytically active metal sites, sacrificial sites, remote curing agent sites, and a solid ion conductor component. These units work together through a specific spatial arrangement and chemical property matching to achieve their functions.

[0036] In an application scenario where chlorinated syngas is used as a feedstock to produce chemicals, the persistent ppm-level chloride in the feedstock gas is a key technical obstacle leading to the deactivation of high-performance noble metal or transition metal catalysts. To address this problem, the catalyst of this invention treats chloride ions within the catalyst microenvironment through the synergistic effect of its internal functional components. Specifically, this is achieved by firstly, in the catalyst structure, sacrificial sites, for example, composed of lanthanum oxide (… Nanoclusters formed by ) are configured to interact with platinum ( ) or nickel ( Catalytically active metal sites, such as those for metals, are closely distributed at the nanoscale. As a basic oxide, it reacts with hydrogen chloride ( ) molecules undergo acid-base reactions ( The activation energy of the chemical reaction is lower than that of the chemisorption of chloride ions on noble metal sites, and the reaction kinetic rate is higher. Therefore, when the chlorine-containing reactant stream diffuses into the interior of the catalyst channels, Molecules will be Site-preferential interception and in-situ conversion into chemically stable lanthanum chloride ( This allows the chlorine species to be captured and transformed before the catalytically active metal sites are poisoned, enabling the high activity of the catalyst and its resistance to chlorine poisoning to coexist in the same system.

[0037] Furthermore, considering that fluctuations in upstream gas supply may cause sudden spikes in chloride ion concentration in raw materials during industrial operations, such spikes can quickly consume sacrificial agents adjacent to active sites; to address this situation, the catalyst system of this invention further incorporates spatially separated remote curing agent sites and solid ion conductor components, wherein the remote curing agent sites, for example, potassium carbonate ( ) or calcium oxide ( Its alkalinity and final curing ability against chlorine are higher than those of the sacrificial agent site. Furthermore, through a preparation process, these components are enriched in the outermost layer or macropores of the catalyst particles; simultaneously, solid ion conductor components, such as mesoporous zeolite H-ZSM-5 with proton acidity or supported solid superacids, are also incorporated. An ion transport channel connecting the sacrificial agent site and the remote curing agent site was constructed in the microstructure. During the low-temperature phase of the reaction process, such as the cold start region, ion transport channels are formed. Chlorine-containing intermediates formed after capturing chloride ions (such as...) The thermally induced surface migration rate is low, and the proton environment of this ion transport channel promotes... Dissociation forms mobile lanthanum chloride complex ions (such as...) Driven by a chemical potential gradient, it is transported to the remote curing agent site via ion exchange mechanism and cured through a chemical reaction. During the high-temperature steady-state stage of the reaction process, the surface thermal diffusion mechanism and the ion transport mechanism work together. This synergistic mechanism of buffering-transport-solidification enables the sacrificial agent sites to recover their capture ability through poison migration after being subjected to poisoning shock. This allows the catalyst to effectively cope with fluctuations in impurity concentration throughout the complete operating cycle, including low-temperature start-up.

[0038] To obtain a catalyst possessing the aforementioned specific spatial configuration and function, a three-step ordered impregnation combined with co-impregnation procedure is employed for its preparation. Taking a catalyst as an example, its initial state is defined as: the object of action is a surface area of... Average aperture is spherical Porous carrier; the equipment used was standard wet chemical impregnation and calcination equipment, including a rotary evaporator and a programmable temperature-controlled muffle furnace; the first step was to load the precursor of the solid ionic conductor component, such as a nanocrystalline aqueous dispersion of H-ZSM-5 zeolite, onto a porous carrier using an equal-volume impregnation method. On the carrier, after drying, a preliminary ion conductor network is formed; in the second step, a precursor with a concentration of [missing information] is applied to the remote curing agent sites. potassium nitrate ( (Aqueous solution, by controlling the volume of the impregnation liquid to be less than the total pore volume of the carrier) The pores are impregnated in this manner, so that... The particles are enriched in the outer layer and macropores, followed by preliminary calcination; in the third step, the precursors of the catalytically active metal sites (such as chloroplatinic acid) are added. ) and precursors at sacrificial sites (such as lanthanum nitrate) The components are dissolved together in deionized water to prepare a mixed impregnation solution, which is then loaded onto the porous support treated in the previous steps using an equal-volume co-impregnation method; in the fourth step, the finally impregnated support is subjected to... Drying and High-temperature roasting Within hours, all precursors decompose in situ, eventually forming on the carrier surface. Nanoparticles and The nanoclusters are distributed in close proximity, and both are remotely connected. The ordered spatial structure between the curing traps, connected by an H-ZSM-5 network, utilizes wet chemical methods to achieve a specific arrangement of functional components at the nano and micro scales by controlling the impregnation sequence and conditions.

[0039] This invention also provides a method for online determination of the remaining sacrificial agent content within the catalyst and identification of its consumption mode, the method utilizing sacrificial agent sites. The catalytic activity of a specific probe reaction; at a point where the health status of the catalyst needs to be diagnosed, the operating procedure is determined as follows: a fluid pulse containing specific probe molecules is introduced into the feed stream in contact with the catalyst via a precision metering pump and valve system connected in parallel with the main feed line, the probe molecules being selected as a sacrificial site in an effective state ( Characteristic endothermic reactions can occur at the catalytic active site ( ) and inactive sacrificial agent sites ( Substances that do not react or react negligibly, such as isopropanol; when isopropanol molecules flow through healthy... At the catalyst bed outlet, an endothermic dehydration reaction occurs, producing propylene and water, resulting in a measurable temporary decrease in the catalyst bed outlet temperature. This process is quantified by monitoring the temperature change in real time using a type K thermocouple located at the catalyst bed outlet and recording the maximum value of the temporary decrease in catalyst bed outlet temperature caused by the characteristic endothermic reaction. To establish a deterministic calibration baseline, under the initial operating conditions of the catalyst (running time)... First, a probe pulse injection is performed, and the maximum value of the initial temporary temperature decrease is measured. For example, measured After the catalyst has been running for a period of time t, the same probe injection procedure is executed again, and the maximum value of the current temporary temperature decrease is measured. For example, in Hours later, it was measured Finally, the remaining amount of sacrificial agent at the site is characterized by the ratio of the maximum value of the temporary temperature decrease measured at the current operating time to the value measured under initial operating conditions. In this example, That is, the remaining effective amount of the sacrificial agent This method transforms the internal chemical state into an externally measurable physical signal related to the remaining quantities, providing operators with a basis for predicting the remaining protective life of the catalyst and determining replacement cycles.

[0040] Furthermore, to diagnose the sacrificial agent consumption pattern, the measurement also includes analyzing the dynamic morphological characteristics of the response curve of the temporary temperature decrease over time. These dynamic morphological characteristics mainly include the peak width of the response curve, such as the half-maximum width (WHM) and the response delay time from probe injection to the occurrence of the lowest temperature point. The diagnostic logic is based on the principle that different poisoning patterns lead to differences in the spatial distribution of effective sacrificial agent sites within the bed, thus affecting the mass transfer and reaction behavior of probe molecules as they pulse through the bed. The judgment procedure is quantified as follows: when the integral area of ​​the response curve decreases, and the changes in its peak width and response delay time are within a first predetermined range (e.g., the rate of change is less than a certain value), the overall situation is as follows: When the system identifies a chronic uniform poisoning mode, this corresponds to a situation where the persistently low concentration of chlorine in the raw material leads to the slow and uniform consumption of the sacrificial agent throughout the bed. When the integral area of ​​the response curve decreases, and the decrease in its peak width exceeds a second predetermined threshold, for example, a decrease exceeding... Furthermore, the increase in its response latency exceeds a third predetermined threshold, for example, an increase exceeding... If the situation is identified as acute local poisoning, it corresponds to a high concentration of chlorine shock that causes the sacrificial agent in the front section of the catalyst bed to be rapidly saturated and ineffective, causing the effective reaction zone to move downstream, thus providing process-level information support for fault diagnosis and preventive maintenance of the upstream process.

[0041] In a specific embodiment of the present invention, in order to achieve a synergistic effect and optimized balance between catalytic activity, chlorine poisoning resistance and ion transport efficiency, the loading amount of each functional component on the porous support is one of the key technical features for achieving the beneficial effects of the present invention. Based on the total mass of the catalyst, the loading amount of the catalytically active metal sites is typically 0.1-5.0 wt%; the loading amount of the sacrificial agent sites is 1.0-20.0 wt%; the loading amount of the remote curing agent sites is 0.5-10.0 wt%; and the loading amount of the solid ion conductor component is 1.0-30.0 wt%. Within this range, the proportions ensure that each functional unit possesses the necessary basic material quantity to function effectively and forms an effective spatial synergistic structure. As a preferred embodiment of the invention, to maximize the catalyst's anti-poisoning lifetime and impurity impact tolerance while ensuring high catalytic activity, the loading amounts of each component are further preferably: 0.5-2.0 wt% for the catalytically active metal sites; 3.0-10.0 wt% for the sacrificial agent sites; 1.0-5.0 wt% for the remote curing agent sites; and 5.0-15.0 wt% for the solid ion conductor component. When the content of each component is within this preferred range, the catalytically active metal sites can be fully exposed, while the sacrificial agent sites in their nano-adjacent regions are sufficient to form an effective preferential adsorption barrier, and the remote curing agent and ion conductor network can also provide sufficient poison migration and curing capabilities. From the perspective of atom economy and functional site interaction, the molar ratio between the sacrificial agent sites and the catalytically active metal sites is also a core parameter affecting catalyst performance. Preferably, the molar ratio of the sacrificial metal element to the catalytically active metal element ranges from 5:1 to 50:1. This molar ratio ensures that there are a sufficient number of sacrificial sites around each catalytic active site to form local protection, thereby effectively intercepting diffused chlorine species, but without causing physical coverage or electronic modification effects on the active sites due to excessive accumulation of sacrificial agents, thus maintaining the inherent high reactivity of the catalyst.

[0042] Example 1: In a continuous operation using coke oven gas as feedstock for Fischer-Tropsch synthesis via a fixed-bed reactor, the chloride ion concentration of the feedstock gas is controlled below 1 ppm after treatment by an upstream purification unit. When this purification unit experiences a brief 30-minute malfunction, a pulse of hydrogen chloride at a concentration of 50 ppm enters the reactor containing the gas described in the aforementioned specific embodiment. When the modified catalyst is in the reactor, the synergistic protection mechanism inside the catalyst is triggered.

[0043] When the poisoning pulse reaches the front section of the catalyst bed, a high concentration of... Molecular orientation towards catalytically active metal sites Diffusion, but due to its proximity to the sacrificial site at the nanoscale. The chemical reactions between them have a higher priority, most of them When molecules come into contact with Before the site was Capture and transform into chlorine-containing intermediate species This process enables the core of the catalytic reaction to... The site retains its structure and function in the initial stages of the poisoning shock; because Concentrations far exceeded steady-state levels, in the front section of the bed. The sacrificial agent sites tend to saturate within a short time. Under these conditions, the interaction between the remote curing agent sites and the solid ionic conductor components begins to maintain the overall function of the catalyst. At the reaction temperature, the previously... Chlorine-containing intermediate species formed by site capture It begins to migrate from the vicinity of the catalytic active site and, through the ion transport channels constructed by the solid ion conductor component H-ZSM-5, moves to the remote curing agent sites that are spatially farther away from the active site. The location shifted, and this migration process was for the subsequent attack. The molecule frees up new sacrificial sites, forming a dynamic buffer capacity. Simultaneously, through the active transfer of toxins, it avoids excessive accumulation of chlorine-containing species in the active region. When the migrating chlorine-containing intermediate species reaches the remote curing agent site, a chemical curing reaction occurs, ultimately releasing the chloride ions... The form is fixed in a region far from the catalytic core. This process combines the high reaction kinetics of the sacrificial agent site with the high capacity and high stability of the remote curing agent site, allowing the high activity and anti-poisoning durability of the catalyst to coexist in the same system.

[0044] After the 30-minute poisoning pulse passed through the entire catalyst bed, the upstream purification unit returned to normal, and the chloride ion concentration in the feed gas dropped to below 1 ppm. Online monitoring data showed that the total conversion rate of the catalyst only experienced a slight and temporary decrease, and recovered to more than 98% of the level before the poisoning impact within a few hours. This avoided the formation of uncontrolled hot spots in the reaction zone and unplanned shutdowns that could have been caused by the rapid failure of the front section of the bed. The entire catalyst system maintained the continuity and stability of operation after the sudden fluctuation in the concentration of impurities in the feed.

[0045] Example 2: To quantitatively evaluate the performance of the aforementioned technical solution under continuous chlorine-containing environment and instantaneous high-concentration chlorine shock, this example established a catalyst performance evaluation test platform. The core of this platform is an atmospheric pressure fixed-bed quartz microreactor system with a reaction tube inner diameter of 10 mm. Temperature control is achieved using a programmable temperature-controlled electric heater and a K-type armored thermocouple, with an accuracy of ±1°C. The flow rates of the feed gas and chlorine-containing gas are controlled by a multi-channel mass flow controller with a full-scale accuracy of ±1%. The reactor outlet gas components are analyzed using an online gas chromatograph to calculate the carbon monoxide conversion rate in the feed gas. This conversion rate serves as an indicator for evaluating catalyst activity. Three catalyst sample groups were prepared for comparative evaluation in this experiment. Control group A contained no anti-toxic functional components. Catalyst; Control group B contains only sacrificial sites. Catalyst; the sample group of this invention is prepared according to the method in the specific embodiments, and completely includes catalytically active metal sites, sacrificial agent sites, remote curing agent sites, and solid ion conductor components. Modified catalyst; all experiments were conducted under the following reaction conditions: reaction temperature 400°C. The reaction pressure was 0.1 MPa, and the simulated syngas volume hourly space velocity was... The raw gas composition is .

[0046] The experimental procedure consisted of two phases. The first phase was a chronic poisoning test lasting 100 hours, in which a concentration of 2 ppm was continuously introduced into the raw material gas under standard reaction conditions. The second stage is an acute poisoning shock test, at the 100th hour, the raw gas... The concentration was increased to 50 ppm and maintained for 1 hour, then reduced to 2 ppm and continued for 200 hours. During the experiment, the carbon monoxide conversion rate of each group showed different trends over time. In the early stage of chronic poisoning, all three groups showed an initial conversion rate of approximately 99%. As time progressed, the conversion rate of control group A decreased significantly, dropping to 38.5% after 100 hours, while control group B and the group of this invention maintained high stability, with conversion rates remaining at 96.1% and 97.5%, respectively. This phenomenon indicates that the introduction of sacrificial agent sites delayed the catalyst's degradation at low concentrations. Inactivation under chlorine conditions; after an acute poisoning shock at 100 hours, the performance of each group showed further differentiation; specifically, the conversion rate of control group B decreased from 96.1% before the shock to 25.3% within 1 hour of the shock, and failed to recover during the subsequent recovery phase, reaching 24.1% by the end of 200 hours. This indicates that its sacrificial sites were saturated when faced with a high concentration of chlorine shock, leading to irreversible poisoning of the catalytic active sites; in contrast, the conversion rate of the sample group of this invention, after experiencing the same shock, only temporarily decreased from 97.5% before the shock to 89.5%, and... After the concentration was restored to 2 ppm, its activity showed recovery ability. At the end of the total 200-hour operation time, the conversion rate was still maintained at 94.2%. The mechanism of this difference is that the buffer-transport-solidification synergistic mechanism inside the sample of the present invention can migrate the chlorine species temporarily captured by the sacrificial agent site to the remote solidifying agent site for storage when facing the poisoning peak, thereby restoring the protective ability of the sacrificial agent site adjacent to the active center. The test results show that compared with catalysts without anti-poisoning components or containing only a single sacrificial agent component, the multifunctional synergistic catalyst provided by the present invention, which includes sacrificial agent sites, remote solidifying agent sites and solid ion conductor components, shows higher stability in long-term chlorine-containing operating environments and has tolerance and performance recovery ability to sudden increases in chloride concentration in the raw materials.

[0047] Example 3: This example combines Figures 1 to 3 This document describes a modified catalyst resistant to chloride ion poisoning and its preparation method. Figure 1 As shown in the figure, solid arrows represent the direction of process progression, dashed boxes are used to distinguish between the two working states of effective and saturated sacrificial sites, and dashed arrows indicate the maintenance or protection of the state. When chlorine-containing feed gas enters the catalyst, hydrogen chloride molecules diffuse close to the functional sites. When the sacrificial site is effective, it will preferentially capture hydrogen chloride and form lanthanum chloride, thereby protecting the catalytically active metal site. This allows the clean feed gas to continue to react and be normally catalytically converted, maintaining high activity and generating the main reaction product. However, when the sacrificial site is saturated, hydrogen chloride molecules will directly contact the catalytically active metal site, leading to the risk of poisoning and deactivation and reducing its activity, ultimately affecting the product outflow from the reactor.

[0048] like Figure 2 As shown, this figure is a comparison of the outlet temperature response curves of the online diagnostic method under different poisoning modes. The horizontal axis represents time (in seconds), and the vertical axis represents the temperature decrease (in units of time). The figure shows the response curves under three conditions. The initial state curve shows the deepest temperature decrease. The temperature decrease of the chronic uniform poisoning curve is reduced, but the overall shape is similar to that of the initial state. The temperature decrease of the acute local poisoning curve is reduced more significantly, and its response peak shape is also significantly changed.

[0049] like Figure 3 As shown, this figure begins with the introduction of probe molecular pulses, followed by monitoring of the outlet temperature change caused by the characteristic endothermic reaction, and analysis of the dynamic morphology of the response curve. On the one hand, this analysis can directly output the sacrificial agent balance, providing a basis for subsequent replacement decisions. On the other hand, by judging whether the peak width and delay time changes are within a first predetermined range, the specific consumption mode can be identified. If it is judged to be yes, it is identified as a chronic uniform poisoning mode in which the sacrificial agent in the entire bed is slowly and uniformly consumed. If it is judged to be no, it is identified as an acute local poisoning mode in which the sacrificial agent in the front section of the bed is rapidly saturated and ineffective. The identification results of both modes can be used as outputs to provide information support for fault diagnosis and preventive maintenance of upstream processes.

[0050] like Figure 4 As shown in the schematic diagram, this structure illustrates the various functional components within a porous carrier (such as...). The spatial arrangement of the components is shown in the diagram, where solid arrows represent diffusion paths of chemical species, dashed arrows represent migration paths of chlorine-containing intermediates in ion transport channels, and the interactions between functional units; catalytic active regions (such as...) ) and sacrificial site (e.g. They are distributed close together at the nanoscale, and are transported by ion channels (such as...) ) is connected to spatially separated remote curing regions, which contain remote curing agent sites (such as This configuration allows for the diffusion of chlorinated species (such as...) ) are preferentially captured by sacrificial agent sites and transformed into chlorine-containing intermediates (such as The light gray lines next to it represent the intermediate species that subsequently migrates to the remote curing zone via ion transport channels, undergoes a curing reaction, and is ultimately fixed into a stable compound (such as...). This allows the sacrificial sites adjacent to the catalytic active region to be regenerated, thereby achieving closed-loop protection of the catalyst.

[0051] Example 4: This example provides an engineering procedure for calibrating the aforementioned online diagnostic method, used to establish a quantitative correspondence between the online diagnostic signal and the actual remaining protective capacity of the catalyst; before an industrial reactor loaded with the modified catalyst of this invention is put into operation, the maximum value of the temporary decrease in catalyst bed outlet temperature measured by the probe molecule pulse injection method needs to be determined. This was converted into a quantitative assessment of the remaining amount of sacrificial agent sites in the catalyst. To establish this quantitative relationship, an offline experimental calibration procedure was performed. The initial state of this procedure was defined as follows: the subjects were five unused catalyst samples from the same batch as the catalyst loaded in the main reactor, each sample weighing 10.0 g; the enabling environment was a laboratory-scale fixed-bed microreactor system with specifications consistent with that in Example 2, which was equipped with a controllable... A metering device for the total amount of gas injected; in this embodiment, the sacrificial component in the catalyst sample group used. The loading rate is 5.0 wt%, based on which its theoretical maximum chlorine capture capacity is calculated to be The calibration process begins by establishing a baseline point. The first catalyst sample is assembled into a microreactor and tested under standard reaction conditions (400...). At a pressure of 0.1 MPa, a single pulse injection of the probe molecule isopropanol was performed, and the maximum value of the transient temperature decrease in its initial state was measured. This value corresponds to 100% of the effective amount of the sacrificial agent.

[0052] Subsequently, by constructing correlated data points through a step-by-step controlled poisoning experiment, the second catalyst sample was assembled into a microreactor, and under standard reaction conditions, a known concentration of [a specific substance] was continuously introduced into the feed gas. The gas was subjected to the process until the total amount of chloride ions absorbed by the sample reached its theoretical maximum chloride capture capacity. 20% of After that, access was stopped. The gas was stabilized in a pure feed gas environment, and then a probe molecular pulse injection was performed again. The maximum value of the temporary temperature decrease at this point was measured. Using the same operating procedures, the third, fourth, and fifth catalyst samples were pre-poisoned to 40%, 60%, and 80% of their theoretical maximum chlorine capture capacity, respectively, and the corresponding values ​​were measured. , and The remaining effective amount of sacrificial agent (100%, 80%, 60%, 40%, 20%, respectively) was compared with the normalized temperature signal. By establishing a correlation, a calibration curve for this specific catalyst system can be plotted. This calibration procedure allows for a quantitative correlation between an in-situ measured physical signal and the intrinsic chemical state of the catalyst. The results of this calibration experiment show an approximately linear relationship between the two, based on which a conversion model can be established, such as: the remaining effective amount of sacrificial agent (%). ,in, These are calibration coefficients obtained by fitting experimental data; thus, operators in the industrial field can use this calibration curve or conversion model to adjust the values ​​measured online from the main reactor. The value is converted into a quantitative prediction of the catalyst's remaining protection capability, providing a data basis for formulating preventive maintenance and optimizing operating cycles.

[0053] Example 5: During the initial start-up and commissioning of a reactor for processing chlorinated syngas, to verify the poison migration capability of the modified catalyst under low-temperature conditions, the reactor bed loaded with the catalyst sample of this invention was programmed to rise to a specific temperature and maintained at 200°C. This temperature is below the threshold for significant thermal migration of chlorine-containing intermediates. Under these conditions, the catalytically active metal sites have no significant catalytic activity for the main reaction, but the sacrificial sites do. Chemical adsorption can be carried out effectively.

[0054] At this temperature, a known total amount of... The pulse, the total amount of which is set to allow the sacrificial sites in the first 10% region of the catalyst bed to reach 50% of their theoretical saturation capacity, is stopped after injection. And continue in 200 The bed was kept in a pure feed gas atmosphere for 2 hours; then, isopropanol probe molecular pulses were injected and the bed outlet was measured. The measured The values ​​were converted using a pre-established calibration relationship. The results showed that the effective residual amount of sacrificial sites in the front section of the bed was higher than 50%, indicating that the chloride species previously captured by the sacrificial sites had migrated from the front to the back of the catalyst bed through the ion transport channels mediated by the solid ion conductor component. The results of this procedure show that the catalyst's protection mechanism is effective under low-temperature start-up conditions and can protect the catalytic active sites before entering the high-temperature reaction zone.

[0055] Example 6: This example provides a standardized engineering procedure for constructing a baseline response model for the aforementioned online diagnostic system. Before an industrial reactor loaded with the modified catalyst of this invention is put into formal operation, a baseline model containing standard excitation signal parameters and characteristic state response signal morphology needs to be established for the diagnostic system. This model will serve as a reference for subsequent online monitoring and state assessment. The procedure first involves determining the standard excitation signal, i.e., the injection parameters of the probe molecules. When the reactor is in standby mode and only pure feed gas passes through the catalyst bed at standard space velocity, an isopropanol probe molecule pulse is injected into the feed gas with an initial total injection amount, i.e., the total molar amount is 0.01% of the theoretical total molar amount of the bed sacrificial agent, and the signal-to-noise ratio of the bed outlet temperature response signal is measured. Subsequently, the total injection amount of the probe molecules is increased in a stepwise manner until the signal-to-noise ratio of the temperature response signal reaches a preset level that can be stably analyzed, i.e., greater than 20, and the analysis of the outlet gas components confirms that no by-products are generated. At this time, the corresponding total injection amount of probe molecules and the injection time are determined as the standard excitation signal parameters for constructing the baseline model.

[0056] Secondly, the response signal of the characteristic state is acquired and solidified. This step is carried out in a pilot test unit loaded with the same batch of catalyst, parallel to the main reactor. First, 2 ppm of [catalyst name missing] is continuously introduced into the pilot unit. Gas is introduced until the theoretical consumption of the catalyst sacrificial site reaches 10%. At this point, a standard excitation signal injection is performed, and the recorded changes in the peak width and response delay time of the temperature response curve relative to the initial state are stored in the baseline model as the first predetermined range defining the chronic uniform poisoning mode. Subsequently, a high concentration of 50 ppm gas is introduced into a new batch of the same catalyst. The pulse is applied, and the total amount injected is controlled to ensure that the theoretical consumption of the sacrificial agent site reaches 10%. The standard excitation signal is injected again, and the recorded decrease in peak width and increase in response delay time are taken as 50% of their respective changes. These are used as the second and third predetermined thresholds for identifying acute local poisoning patterns and stored in the benchmark model. Through this procedure, a benchmark response model containing standard excitation parameters and quantitative decision thresholds is established, enabling the online diagnostic system to be put into operation.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A modified catalyst resistant to chloride ion poisoning, characterized in that, The catalyst comprises a porous support, and the following components dispersed on the porous support: Catalytically active metal site; the catalytically active metal site is Pt; The sacrificial site is located adjacent to the catalytically active metal site at the nanoscale, and the chemical reaction rate between the sacrificial site and chloride ions is higher than that between the catalytically active metal site and chloride ions; the sacrificial site is La2O3. The remote curing agent site is spatially farther away from the catalytically active metal site than the sacrificial agent site; the remote curing agent site is K2CO3; The solid ion conductor component forms an ion transport channel that at least partially connects the sacrificial agent site and the remote curing agent site within the microstructure of the porous carrier; the solid ion conductor component is H-ZSM-5. The ion transport channel captures chloride ions at the sacrificial site, forming a chlorine-containing intermediate species. Under conditions below the threshold temperature at which the chlorine-containing intermediate species undergoes substantial thermal migration, the intermediate species migrates from the sacrificial site to the remote curing agent site and is then chemically reacted with the remote curing agent site to be cured.

2. The chloride ion poisoning resistant modified catalyst according to claim 1, characterized in that, The catalyst is obtained by a preparation method comprising the following steps: first, loading a precursor of a solid ion conductor component onto a porous support to form an ion conductor network; second, loading a precursor of a remote curing agent site onto a porous support loaded with the ion conductor network; third, co-impregnating and loading a precursor of a catalytically active metal site and a precursor of a sacrificial agent site onto the porous support after the second step treatment; and fourth, calcining the porous support after the third step treatment.

3. The chloride ion poisoning resistant modified catalyst according to claim 1, characterized in that, The porous support is alumina, silica, or mesoporous molecular sieve.

4. A method for online diagnosis of the remaining amount of sacrificial sites in a catalyst as claimed in claim 1, the method comprising the steps of: introducing a fluid pulse containing probe molecules into a feed stream in contact with the catalyst, the probe molecules undergoing a characteristic endothermic reaction at the sacrificial sites; measuring a temporary decrease in the catalyst bed outlet temperature caused by the characteristic endothermic reaction; and calculating a ratio of the maximum value of the temporary decrease in temperature measured at the current operating time to the maximum value of the temporary decrease in temperature measured at the catalyst under initial operating conditions, the ratio representing the remaining amount of sacrificial sites.

5. The method according to claim 4, characterized in that, The measurement also includes the dynamic morphological characteristics of the response curve of the temporary decrease in temperature over time, including the peak width and response delay time of the response curve; the method also includes identifying the spatial consumption distribution pattern of sacrificial agent sites based on the dynamic morphological characteristics of the response curve; when the integral area of ​​the response curve decreases and the changes in its peak width and response delay time are within a first predetermined range, it is identified as a chronic uniform poisoning pattern; and when the integral area of ​​the response curve decreases, the decrease in its peak width exceeds a second predetermined threshold, and the increase in its response delay time exceeds a third predetermined threshold, it is identified as an acute local poisoning pattern.

6. The preparation method of the chloride ion poisoning resistant modified catalyst as described in claim 1, characterized in that, The method includes the following steps: Step a: Load the precursor of the solid ion conductor component onto a porous support to form an ion conductor network; Step b: Load the precursor of the remote curing agent site onto a porous support loaded with an ion conductor network; Step c: The precursors of the catalytically active metal sites and the precursors of the sacrificial sites are co-impregnated and loaded onto the porous support after the aforementioned steps. Step d involves calcining the porous carrier after co-impregnation and loading.

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