A VSP2-RCle combined thermal analysis method for determining catalyst deactivation

Abstract

The present invention belongs to the technical field of catalyst thermal safety analysis, and more particularly to a VSP2-RCe combined thermal analysis method for judging catalyst deactivation, including: (a) catalyst and raw material are mixed to prepare material to be tested I and loaded into a discharge design adiabatic calorimeter VSP2 to simulate the reaction process; the highest reaction temperature Tf reached when the reaction is finished is recorded; (b) the material solid-liquid separation after step (a) test is performed, and after obtaining the deactivated catalyst, material to be tested II is prepared and added to the reactor to react; q is obtained by full-automatic reaction calorimeter RLe calorimetric test; (c) material to be tested I is measured and added to the reactor to react, and system calorimetric test is performed to obtain Q and specific heat capacity Cp; the catalyst is judged to be completely deactivated by each step test result, and it is determined that the temperature at which the catalyst is completely deactivated is Tf. The present invention can judge the highest temperature at which the catalyst is completely deactivated, can reduce investment, and has guiding significance for reaction dangerous scenes.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst thermal safety analysis, and in particular relates to a VSP2-RCle combined thermal analysis method for determining catalyst deactivation. Background Art

[0002] The hydrogenation reaction is a highly exothermic reaction process. Usually, during the normal stage, it is necessary to remove some of the heat released by the hydrogenation reaction through cold water in the jacket to achieve the purpose of controlling the reaction temperature. The most important factor affecting the effect of the hydrogenation reaction is the reaction temperature during the reaction process. If the reaction temperature is too high, the reactants will decompose due to local overheating, and other by-products will be produced during the hydrogenation process, reducing product quality. In addition, as the reaction temperature increases, the reaction rate of the main reaction accelerates, accompanied by side reactions such as product decomposition. In particular, the catalytically active catalyst in the reaction system can accelerate the secondary decomposition of the product and produce gas, which can easily lead to serious consequences such as overheating and overpressure of the equipment and even explosion.

[0003] If the timing of when the catalyst activity decreases with increasing temperature until it becomes inactivated can be accurately determined when the reaction is about to get out of control or has already gotten out of control, the severity of the consequences will be greatly reduced. At the same time, by accurately designing the reactor based on the consequences of the runaway reaction, excessive discharge protection design can be effectively avoided, reducing equipment investment.

[0004] Therefore, it is of great practical significance to study whether the catalyst is completely deactivated and the temperature of complete deactivation under runaway reaction conditions.

[0005] At present, the mainstream international equipment used for reaction heat risk assessment mainly includes the fully automatic reaction calorimeter RLe and the vent design adiabatic calorimeter VSP2 (Vent Sizing Package 2).

[0006] RLe is a fully automatic reaction calorimeter developed by Mettler-Toledo. This type of calorimeter uses batch and semi-batch reactors produced in actual process production as models. It can simulate the specific process and detailed steps of the reaction process while controlling the actual process conditions. It can also accurately monitor and test the process parameters of the chemical reaction, such as temperature, pressure, feeding rate, mixing process, reaction heat flow and heat transfer data. The results obtained can be well scaled up to the production conditions of the actual factory.

[0007] VSP2 (Vent Sizing Package 2) is a vent design adiabatic calorimeter developed by FAUSKE. It can be used directly to test the heat release characteristics and gas production behavior under approximately adiabatic conditions encountered in large-scale production processes of pilot or industrial equipment, including: starting heat release temperature, adiabatic temperature rise, heat release rate, and gas production rate. Based on the test data obtained, the maximum temperature rise and maximum pressure in the event of a process equipment failure (such as cooling failure, stirring failure, or feeding error) can be determined. If combined with the emergency relief design method for runaway chemical reactions proposed by DIERS (Design Institute for Runaway Reaction Emergency Relief Systems), it can also be used for the design of relief devices for process equipment.

[0008] At present, there is no public report on the use of thermal risk assessment equipment to determine the complete deactivation of the catalyst and the deactivation temperature under runaway conditions of hydrogenation reactions. Summary of the Invention

[0009] The objective of the present invention is to provide a VSP2-RCe combined thermal analysis method for determining catalyst deactivation, in response to the practical need to address the consequences of runaway hydrogenation reactions and how to avoid them. This method can effectively determine complete catalyst deactivation and the corresponding maximum temperature and pressure, allowing for precise reactor design, effectively avoiding excessive discharge protection design, and reducing equipment investment. This method has important guiding significance for dangerous scenarios where the presence of a catalytically active catalyst can accelerate product decomposition, leading to runaway reactions and excessive temperatures and pressures.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] A VSP2-RCle combined thermal analysis method for determining catalyst deactivation comprises the following steps:

[0012] (a) mixing a fresh hydrogenation catalyst and a hydrogenation reaction raw material to prepare a test material I containing the hydrogenation catalyst and the hydrogenation reaction raw material;

[0013] The prepared test material I was measured and loaded into the test cell of the discharge design adiabatic calorimeter VSP2, and the reaction process of the test material I was simulated; when the reaction exotherm ended, the experiment was stopped and the maximum reaction temperature Tf reached at the end of the reaction was obtained;

[0014] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, and then performing solid-liquid separation to obtain a recovered catalyst, and then mixing the recovered catalyst with the hydrogenation reaction feed to prepare a test material II containing the recovered catalyst and the hydrogenation reaction feed;

[0015] The material II to be tested is measured and added into a high-pressure reactor, and the material II to be tested is reacted after the temperature and pressure are increased; after the reaction is completed, the system is depressurized and the temperature is lowered;

[0016] The reaction system (from the beginning to the end of the reaction) was calorimetrically tested using a fully automatic reaction calorimeter RLe to obtain the specific heat release q.

[0017] (c) re-weighing the prepared test material I and adding it to the autoclave, and reacting the test material I according to the reaction conditions of step (b); after the reaction is completed, the system is depressurized and cooled;

[0018] The reaction system (from the beginning to the end of the reaction) was calorimetrically tested using a fully automatic reaction calorimeter RLe to obtain the specific heat release Q and specific heat capacity Cp of the reaction;

[0019] Based on the test results of steps (a), (b) and (c), it is determined that the hydrogenation reaction catalyst is completely deactivated, and the temperature at which the hydrogenation catalyst is completely deactivated is determined to be the highest reaction temperature Tf reached at the end of the reaction exotherm in step (a).

[0020] According to the method provided by the present invention, in some embodiments, the hydrogenation reaction raw materials are selected from one or more of aniline, p-aminotoluene, m-phenylenediamine, o-phenylenediamine, p-chloroaniline, m-phenylenediamine and p-phenylenediamine, preferably selected from one or more of aniline, p-aminotoluene, m-phenylenediamine, p-chloroaniline and m-phenylenediamine.

[0021] In some embodiments, the hydrogenation catalyst is selected from one or more of Pd / C, Pt / C, Ru / C, Rh / C, Pd / Al2O3, Pt / Al2O3, Ru / Al2O3, Rh / Al2O3, Co / Al2O3 and Ni / Al2O3, preferably selected from one or more of Pd / C, Co / Al2O3, Ru / Al2O3, Pt / Al2O3 and Ni / Al2O3.

[0022] In some embodiments, the content of the hydrogenation catalyst in the material to be tested I is 0.1-0.8 wt% (for example, 0.15 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%), preferably 0.3-0.6 wt%, based on the weight of the hydrogenation reaction raw materials contained in the material to be tested I.

[0023] According to the method provided by the present invention, in some embodiments, the reaction operation steps in step (a) are:

[0024] The material I to be tested is added to a 110 ml test cell in an amount of 20-50 g (for example, 25 g, 28 g, 32 g, 38 g, 45 g), preferably 30-40 g, and then replaced with nitrogen 3-5 times; the system is heated at a temperature rise rate of 2-6 K / min (for example, 2.5 K / min, 4 K / min, 4.5 K / min, 5.5 K / min), preferably 3-5 K / min, to 50-150 ° C (for example, 60 ° C, 70 ° C, 90 ° C, 100 ° C, 110 ° C, 130 ° C), preferably 80 -120°C; when the reaction temperature stabilizes, the system is pressurized to 1-8 MPa (e.g., 1.5 MPa, 2 MPa, 4 MPa, 5 MPa, 7 MPa), preferably 3-6 MPa; the system is then reacted, and heat is released after the reaction begins; when the temperature rise rate is ≤0.2°C / min (e.g., 0.01°C / min, 0.02°C / min, 0.05°C / min, 0.12°C / min, 0.15°C / min), preferably when the temperature rise rate is ≤0.1°C / min, the reaction exotherm ends, the experiment is stopped, and the temperature is cooled to room temperature;

[0025] Obtain the maximum reaction temperature Tf reached by the system at the end of the reaction (hydrogenation catalyst cooling failure).

[0026] In some embodiments, the reaction system is stirred in step (a) using a magnetic stirrer at a stirring speed of 100-500 rpm (e.g., 110 rpm, 150 rpm, 180 rpm, 250 rpm, 300 rpm, 450 rpm), preferably 200-400 rpm.

[0027] In step (a), for example, the reaction temperature and reaction pressure under adiabatic conditions and their changes over time can be obtained by measuring data. Tf can be obtained by recording during the test process of step (a), or by determining the change pattern of the reaction temperature over time obtained by the test.

[0028] According to the method provided by the present invention, in some embodiments, the reaction operation steps in step (b) are:

[0029] The material II to be tested is added to a 2L autoclave in an amount of 500-1000 g (for example, 550 g, 650 g, 700 g, 750 g), preferably 600-800 g; then the autoclave is replaced with nitrogen 3-5 times; the system is heated to 50-150°C (for example, 60°C, 70°C, 90°C, 100°C, 110°C, 130°C), preferably 80-120°C; when the reaction temperature is stable, a pre-calibration is performed, and then the system is pressurized to 2-8 MPa (for example, 2.5 MPa, 3 MPa, 4.5 MPa, 5 MPa, 7 MPa), preferably 4-6 MPa; then the system is reacted for 2-6 h (for example, 2.5 h, 3.5 h, 4 h, 5.5 h), preferably 3-5 h. After the reaction is completed, a post-calibration is performed, and finally the temperature is reduced and the pressure is released, and the experiment is stopped.

[0030] In some embodiments, step (b) uses a self-priming stirring paddle to stir the reaction system, and the stirring speed is 600-1200 rpm (for example, 650 rpm, 750 rpm, 900 rpm, 1100 rpm), preferably 800-1000 rpm.

[0031] In some embodiments, the content of the recovered catalyst in the test material II prepared in step (b) is in the range of 0.1-0.8 wt% (for example, 0.15 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%), preferably 0.3-0.6 wt%, based on the weight of the hydrogenation reaction raw materials contained in the test material II.

[0032] In step (c), the reaction operation process and condition setting of the system can refer to step (b), for example.

[0033] In step (b) and step (c), after the reaction is completed, the raw material conversion rate and product selectivity can be measured by gas chromatography to assist in determining the properties of the reaction products and the state of the catalyst (such as whether it is deactivated or the degree of deactivation).

[0034] In some embodiments, the step of determining that the hydrogenation reaction catalyst is completely deactivated comprises:

[0035] (1) Calculate the adiabatic temperature rise based on the highest reaction temperature Tf reached by the system at the end of the reaction measured in step (a):

[0036] Adiabatic temperature rise = Tf - Tp, where Tp is the reaction temperature in step (a);

[0037] (2) calculating the ratio q / Q of the reaction specific exotherm q and the reaction specific exotherm Q measured in steps (b) and (c);

[0038] (3) Calculate the adiabatic temperature rise of the main reaction based on the reaction specific heat release Q and specific heat capacity Cp measured in step (c):

[0039] Adiabatic temperature rise of the main reaction = Q / Cp;

[0040] (4) When Tf - Tp ≤ Q / Cp and q / Q ≤ 2% (for example, 0.01%, 0.05%, 0.1%, 0.5%, 1.5%), preferably Tf - Tp ≤ Q / Cp and q / Q ≤ 1%, it is determined that the hydrogenation catalyst has been completely deactivated. The temperature at which the hydrogenation catalyst is completely deactivated is determined to be the highest reaction temperature (the highest temperature reached by the reaction when the catalyst cooling fails) Tf reached at the end of the reaction exotherm.

[0041] In the present method, the reaction process is first simulated using a VSP2 adiabatic calorimeter with a venting design. This allows the temperature and pressure from the reaction to the cooling failure condition, as well as the maximum temperature Tf, that the system can reach, to be measured. Secondly, a reaction calorimetry test is performed on the recovered catalyst after the VSP2 test using a fully automated reaction calorimeter (RCe), to determine the specific heat release (q). Finally, a reaction calorimetry test is performed on the fresh hydrogenation catalyst using the fully automated reaction calorimeter (RCe) under the same conditions, to determine the specific heat release (Q) and specific heat capacity (Cp). When certain conditions are met, such as Tf - Tp ≤ Q / Cp and q / Q ≤ 2%, the catalyst is considered completely deactivated. Furthermore, the temperature at which the catalyst is completely deactivated is determined to be the maximum temperature Tf reached during the cooling failure condition.

[0042] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0043] The combined thermal analysis method of the present invention can ensure that the results of determining catalyst deactivation are accurate and reliable, and has a certain degree of universality, providing effective technical support for judging the complete deactivation degree and deactivation temperature of hydrogenation catalysts in various hydrogenation reactions; the temperature at which the catalyst is completely deactivated is obtained through the combined thermal analysis method, which can be used to accurately design the reactor, effectively avoid excessive temperature protection design, and reduce equipment investment. It is of great significance, in particular, for dangerous scenarios in which the presence of a catalytically active catalyst can accelerate product decomposition, leading to runaway reactions and overtemperature and overpressure. DETAILED DESCRIPTION

[0044] In order to understand the technical features and content of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0045] <Source of raw materials>

[0046] Aniline, p-aminotoluene, m-phenylenediamine, p-chloroaniline, m-phenylenediamine, content ≥99.8wt%, Shanghai Taihe Chemical Co., Ltd.

[0047] Catalysts Pd / C, Ru / Al2O3, and Pt / Al2O3, each containing 5% precious metal, are from Xi'an Kaili New Materials Co., Ltd.

[0048] Catalyst Co / Al2O3, catalyst Ni / Al2O3, wherein the metal content is 10%, Xi'an Kaili New Materials Co., Ltd.

[0049] <Test Method>

[0050] Gas chromatograph: Shimadzu GC-2014 (FID) detector, SE-30 capillary column (φ0.30 mm×30 m), inlet temperature of 280°C, detector temperature of 280°C; heating program: 60°C, constant temperature for 2 min, then increased to 280°C at a rate of 30°C / min and held for 5 min.

[0051] Example 1

[0052] The VSP2-RCle combined thermal analysis method for determining catalyst deactivation and its corresponding deactivation temperature comprises the following steps:

[0053] (a) A fresh hydrogenation catalyst Pd / C was mixed with aniline raw material to prepare a test material I; the Pd / C content in the test material I was 0.3 wt% based on the weight of aniline;

[0054] 30 g of the prepared test material I was measured and loaded into the 110 ml test cell of the discharge design adiabatic calorimeter VSP2. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a magnetic stirrer at 100 rpm. The temperature of the system was raised to 50°C at a temperature rise rate of 3 K / min. When the reaction temperature stabilized, the hydrogen pressure in the system was raised to 2 MPa. The reaction began to release heat. When the temperature rise rate reached 0.2°C / min, the reaction exotherm ended, the experiment was stopped, and the temperature was cooled to room temperature.

[0055] It was recorded that the highest reaction temperature Tf reached at the end of the reaction exotherm was 254°C, and the normal process temperature Tp was 50°C, so the adiabatic temperature rise Tf-Tp was 204°C.

[0056] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, performing solid-liquid separation to obtain a recovered catalyst Pd / C, and then mixing the recovered catalyst Pd / C with aniline to prepare a test material II; the recovered catalyst Pd / C content in the test material II is 0.3 wt % based on the weight of aniline;

[0057] Measure 600 g of the prepared test material II and add it to a 2 L autoclave. Replace the atmosphere with nitrogen 3-5 times. Stir the reaction system with a self-priming stirring paddle at 800 rpm. Raise the temperature of the system to 50°C. When the reaction temperature stabilizes, perform a pre-calibration and then increase the hydrogen pressure in the system to 2 MPa. After the system reacts for 6 h, perform a post-calibration and finally cool and release the pressure before stopping the experiment.

[0058] The process from the beginning to the end of the reaction was calorimetrically tested using a fully automatic reaction calorimeter RLe, and the specific heat release q of the reaction system was measured to be 5.0 J / g; the raw material conversion rate was measured to be 0.53% and the product selectivity was 100% by gas chromatography.

[0059] (c) 600 g of the prepared test material I containing fresh catalyst Pd / C and aniline was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 800 rpm. The system was heated to 50°C. After the reaction temperature stabilized, a pre-calibration was performed. The hydrogen pressure in the system was then increased to 2 MPa. After the system reacted for 6 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0060] The reaction was calorimetrically tested from the start to the end using a fully automatic reaction calorimeter (RCe). The specific heat release Q of the reaction system was measured to be 910 J / g, the specific heat capacity Cp was 2.4 J / g / °C, and the adiabatic temperature rise Q / Cp of the main reaction was 379.2°C. Gas chromatography determined that the raw material conversion rate was 100% and the product selectivity was 99.9%.

[0061] According to the experimental data obtained in steps (a), (b) and (c), Tf-Tp=204°C<Q / Cp=379.2°C and q / Q=0.55%<1%, it can be determined that the Pd / C catalyst has been completely deactivated. The temperature at which the catalyst is completely deactivated is the highest reaction temperature of 254°C reached when cooling fails.

[0062] Example 2

[0063] The VSP2-RCle combined thermal analysis method for determining catalyst deactivation and its corresponding deactivation temperature comprises the following steps:

[0064] (a) fresh hydrogenation catalyst Ru / Al2O3 was mixed with para-aminotoluene raw material to prepare a test material I; the test material I had a Ru / Al2O3 content of 0.5% based on the weight of para-aminotoluene;

[0065] 35 g of the prepared test material I was measured and loaded into the 110 ml test cell of the discharge design adiabatic calorimeter VSP2. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a magnetic stirrer at 200 rpm. The temperature of the system was raised to 80°C at a temperature rise rate of 4 K / min. After the reaction temperature stabilized, the hydrogen pressure in the system was raised to 4 MPa. The reaction began to release heat. When the temperature rise rate reached 0.1°C / min, the reaction exotherm ended, the experiment was stopped, and the temperature was cooled to room temperature.

[0066] It was recorded that the highest reaction temperature Tf reached at the end of the reaction exotherm was 220°C, and the normal process temperature Tp was 80°C, so the adiabatic temperature rise Tf-Tp was 140°C.

[0067] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, performing solid-liquid separation to obtain a recovered Ru / Al2O3 catalyst, and then mixing the recovered Ru / Al2O3 catalyst with para-aminotoluene to prepare a test material II; the recovered Ru / Al2O3 catalyst content in the test material II is 0.5% based on the weight of para-aminotoluene;

[0068] 700 g of the prepared test material II was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 1000 rpm. The system was heated to 80°C. When the reaction temperature stabilized, a pre-calibration was performed, and then the hydrogen pressure in the system was increased to 4 MPa. After the system reacted for 5 h, a post-calibration was performed, and finally the temperature was reduced and the pressure was released, and the experiment was stopped.

[0069] The reaction process was calorimetrically tested from the beginning to the end using a fully automatic reaction calorimeter (RCe), and the specific heat release q of the reaction system was measured to be 8.0 J / g. Gas chromatography revealed a raw material conversion rate of 1.21% and a product selectivity of 100%.

[0070] (c) 700 g of the prepared test material I containing fresh catalyst Ru / Al2O3 and p-aminotoluene was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 1000 rpm. The system was heated to 80°C. After the reaction temperature stabilized, a pre-calibration was performed. The hydrogen pressure in the system was then increased to 4 MPa. After the system reacted for 5 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0071] The reaction was calorimetrically tested from the start to the end using a fully automatic reaction calorimeter (RCe). The specific heat release Q of the reaction system was measured to be 654 J / g, the specific heat capacity Cp was 2.8 J / g / °C, and the adiabatic temperature rise Q / Cp of the main reaction was 233.6°C. Gas chromatography determined that the raw material conversion rate was 100% and the product selectivity was 99.5%.

[0072] According to the experimental data obtained in steps (a), (b) and (c), Tf-Tp=140°C<Q / Cp=233.6°C, and q / Q=1.22%<2%, it can be determined that the Ru / Al2O3 catalyst has been completely deactivated. The temperature at which the catalyst is completely deactivated is the highest reaction temperature of 220°C reached when cooling fails.

[0073] Example 3

[0074] The VSP2-RCle combined thermal analysis method for determining catalyst deactivation and its corresponding deactivation temperature comprises the following steps:

[0075] (a) Mixing a fresh catalyst containing Co / Al2O3 with a raw material of m-phenylenediamine to prepare a test material I; the test material I has a Co / Al2O3 content of 0.6% based on the weight of m-phenylenediamine;

[0076] 40 g of the prepared test material I was measured and loaded into the 110 ml test cell of the discharge design adiabatic calorimeter VSP2. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a magnetic stirrer at 300 rpm. The temperature of the system was raised to 100°C at a temperature rise rate of 5 K / min. After the reaction temperature stabilized, the hydrogen pressure of the system was increased to 6 MPa. The reaction began to release heat. When the temperature rise rate reached 0.15°C / min, the reaction exotherm ended, the experiment was stopped, and the temperature was cooled to room temperature.

[0077] It was recorded that the highest reaction temperature Tf reached at the end of the reaction exotherm was 322°C, and the normal process temperature Tp was 100°C, so the adiabatic temperature rise Tf-Tp was 222°C.

[0078] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, and performing solid-liquid separation to obtain a recovered catalyst Pd / C, and then mixing the recovered catalyst Co / Al2O3 with m-phenylenediamine to prepare a test material II; the recovered catalyst Co / Al2O3 content in the test material II is 0.6% based on the weight of m-phenylenediamine;

[0079] 800 g of the prepared test material II was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 1200 rpm. The system was heated to 100 ° C. When the reaction temperature stabilized, a pre-calibration was performed. Then, the hydrogen pressure in the system was increased to 6 MPa. After the system reacted for 4 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0080] The reaction process was calorimetrically tested from the beginning to the end using a fully automatic reaction calorimeter (RCe), and the specific heat release q of the reaction system was measured to be 6.5 J / g. Gas chromatography revealed a raw material conversion rate of 0.92% and a product selectivity of 99.9%.

[0081] (c) 800 g of the prepared test material I containing fresh catalyst Co / Al2O3 and m-phenylenediamine was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 1200 rpm. The system was heated to 100°C. After the reaction temperature stabilized, a pre-calibration was performed. The hydrogen pressure in the system was then increased to 6 MPa. After the system reacted for 4 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0082] The reaction was calorimetrically tested from the start to the end using a fully automatic reaction calorimeter (RCe). The specific heat release Q of the reaction system was measured to be 735 J / g, the specific heat capacity Cp was 2.2 J / g / °C, and the adiabatic temperature rise Q / Cp of the main reaction was 334.1°C. Gas chromatography determined that the raw material conversion rate was 100% and the product selectivity was 99.8%.

[0083] According to the experimental data obtained in steps (a), (b) and (c), Tf-Tp=222°C<Q / Cp=334.1°C, and q / Q=0.88%<1%. It can be determined that the Co / Al2O3 catalyst has been completely deactivated. The temperature at which the catalyst is completely deactivated is the highest reaction temperature of 322°C reached when cooling fails.

[0084] Example 4

[0085] The VSP2-RCle combined thermal analysis method for determining the catalyst and its corresponding deactivation temperature comprises the following steps:

[0086] (a) A fresh hydrogenation catalyst Ni / Al2O3 was mixed with a p-chloroaniline raw material to prepare a test material I; the test material I had a Ni / Al2O3 content of 0.1% based on the weight of p-chloroaniline;

[0087] 20 g of the prepared test material I was measured and loaded into the 110 ml test cell of the discharge design adiabatic calorimeter VSP2. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a magnetic stirrer at 400 rpm. The temperature of the system was raised to 120°C at a temperature rise rate of 6 K / min. After the reaction temperature stabilized, the hydrogen pressure in the system was increased to 8 MPa. The reaction began to release heat. When the temperature rise rate reached 0.05°C / min, the reaction exotherm ended, the experiment was stopped, and the temperature was cooled to room temperature.

[0088] It was recorded that the highest reaction temperature Tf reached at the end of the reaction exotherm was 289°C, and the normal process temperature Tp was 120°C, so the adiabatic temperature rise Tf-Tp was 169°C.

[0089] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, performing solid-liquid separation to obtain a recovered Ni / Al2O3 catalyst, and then mixing the recovered Ni / Al2O3 catalyst with p-chloroaniline to prepare a test material II; the recovered Ni / Al2O3 catalyst content in the test material II is 0.1% based on the weight of p-chloroaniline;

[0090] 500 g of the prepared test material II was measured and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 600 rpm. The system was heated to 120 ° C. When the reaction temperature stabilized, a pre-calibration was performed. Then, the hydrogen pressure in the system was increased to 8 MPa. After the system reacted for 3 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0091] The reaction process was calorimetrically tested from the beginning to the end using a fully automatic reaction calorimeter (RCe), and the specific heat release q of the reaction system was measured to be 4.6 J / g. Gas chromatography revealed a raw material conversion rate of 0.61% and a product selectivity of 99.8%.

[0092] (c) Re-measure 500 g of the prepared test material I containing fresh catalyst Ni / Al2O3 and p-chloroaniline, add it to a 2 L autoclave, and replace it with nitrogen 3-5 times; use a self-priming stirring paddle to stir the reaction system at 600 rpm, and heat the system to 120 ° C. When the reaction temperature stabilizes, perform a pre-calibration, then increase the hydrogen pressure in the system to 8 MPa. After the system reacts for 3 h, perform a post-calibration, and finally cool and release the pressure, and stop the experiment;

[0093] The reaction process was calorimetrically tested from the start to the end using a fully automatic reaction calorimeter (RCe). The specific heat release Q of the reaction system was measured to be 820 J / g, the specific heat capacity Cp was 2.7 J / g / °C, and the adiabatic temperature rise Q / Cp of the main reaction was 303.7°C. Gas chromatography determined that the raw material conversion rate was 100% and the product selectivity was 99.6%.

[0094] According to the experimental data obtained in steps (a), (b) and (c), Tf-Tp=169°C<Q / Cp=303.7°C and q / Q=0.56%<1% are satisfied. It can be determined that the Ni / Al2O3 catalyst has been completely deactivated. The temperature at which the catalyst is completely deactivated is the highest reaction temperature of 289°C reached when cooling fails.

[0095] Example 5

[0096] The VSP2-RCle combined thermal analysis method for determining catalyst deactivation and its corresponding deactivation temperature comprises the following steps:

[0097] (a) A fresh hydrogenation catalyst Pt / Al2O3 was mixed with a meta-xylylenediamine raw material to prepare a test material I; the test material I had a Pt / Al2O3 content of 0.8% based on the weight of the meta-xylylenediamine;

[0098] 50 g of the prepared test material I was measured and loaded into the 110 ml test cell of the discharge design adiabatic calorimeter VSP2. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a magnetic stirrer at 500 rpm. The temperature of the system was raised to 150°C at a temperature rise rate of 4.5 K / min. After the reaction temperature stabilized, the hydrogen pressure in the system was increased to 5 MPa. The reaction began to release heat. When the temperature rise rate reached 0.01°C / min, the reaction exotherm ended, the experiment was stopped, and the temperature was cooled to room temperature.

[0099] It was recorded that the highest reaction temperature Tf reached at the end of the reaction exotherm was 225°C, and the normal process temperature Tp was 150°C, so the adiabatic temperature rise Tf-Tp was 75°C.

[0100] (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, performing solid-liquid separation to obtain recovered Pt / Al2O3 catalyst, and then mixing the recovered Pt / Al2O3 catalyst with m-xylylenediamine to prepare test material II; the content of the deactivated Pt / Al2O3 catalyst in test material II is 0.8% based on the weight of m-xylylenediamine;

[0101] 1000 g of the prepared test material II was measured and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 900 rpm. The system was heated to 150°C. When the reaction temperature stabilized, a pre-calibration was performed, and then the hydrogen pressure in the system was increased to 5 MPa. After the system reacted for 2 h, a post-calibration was performed, and finally the temperature was reduced and the pressure was released, and the experiment was stopped.

[0102] The process from the beginning to the end of the reaction was calorimetrically tested using a fully automatic reaction calorimeter RLe, and the specific heat release q of the reaction system was measured to be 2.5 J / g; the raw material conversion rate was measured to be 0.35% and the product selectivity was 100% by gas chromatography.

[0103] (c) 1000 g of the prepared test material I containing fresh catalyst Pt / Al2O3 and m-xylenediamine was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 900 rpm. The system was heated to 150°C. After the reaction temperature stabilized, a pre-calibration was performed. The hydrogen pressure in the system was then increased to 5 MPa. After the system reacted for 2 h, a post-calibration was performed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0104] The reaction process was calorimetrically tested from the start to the end using a fully automatic reaction calorimeter (RCe). The specific heat release Q of the reaction system was measured to be 760 J / g, the specific heat capacity Cp was 3.1 J / g / °C, and the adiabatic temperature rise Q / Cp of the main reaction was 245.2°C. Gas chromatography determined that the raw material conversion rate was 100% and the product selectivity was 99.7%.

[0105] According to the experimental data obtained in steps (a), (b) and (c), Tf-Tp=75°C<Q / Cp=245.2°C and q / Q=0.33%<1%. It can be determined that the Pt / Al2O3 catalyst has been completely deactivated. The temperature at which the catalyst is completely deactivated is the highest reaction temperature of 225°C reached when cooling fails.

[0106] Comparative Example 1

[0107] Through the continuous application mode of catalyst, the raw material conversion rate and product selectivity are used as the benchmark to determine whether the catalyst has been deactivated. The specific steps are as follows:

[0108] (1) Fresh hydrogenation catalyst Pd / C was mixed with aniline raw material to prepare a test material I; the Pd / C content in the test material I was 0.3 wt% based on the weight of aniline;

[0109] 600 g of the prepared test material I was weighed and added to a 2 L autoclave. The atmosphere was replaced with nitrogen 3-5 times. The reaction system was stirred with a self-priming stirring paddle at 800 rpm. The system was heated to 50°C. When the reaction temperature stabilized, the hydrogen pressure in the system was increased to 2 MPa. After the system reacted for 6 h, the temperature was lowered and the pressure was released, and the experiment was stopped.

[0110] Gas chromatography revealed a feed conversion of 100% and a product selectivity of 99.9%.

[0111] (2) The material after the test was removed from the 2 L autoclave, and then subjected to solid-liquid separation to recover the partially deactivated catalyst Pd / C, which was then mixed with aniline to prepare the test material II; the content of the partially deactivated catalyst Pd / C was 0.3% based on the weight of aniline;

[0112] Measure 600 g of the prepared test material II and add it to a 2 L autoclave. Repeat the above experiment according to step (1);

[0113] Repeat 30-50 times. When the raw material conversion rate is lower than 95%, the product conversion rate and selectivity indicators are unqualified. At this time, it is judged that the catalyst has reached a certain degree of deactivation and cannot be used further. Fresh catalyst needs to be replaced.

[0114] The method of this comparative example can only determine that the catalyst has been partially deactivated rather than completely deactivated, and cannot obtain the temperature corresponding to the complete deactivation of the catalyst.

[0115] While some embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A VSP2-RCe combined thermal analysis method for determining catalyst deactivation, characterized in that: The following steps are involved: (a) mixing a fresh hydrogenation catalyst and a hydrogenation reaction raw material to prepare a test material I containing the hydrogenation catalyst and the hydrogenation reaction raw material; The prepared test material I was measured and loaded into the test cell of the discharge design adiabatic calorimeter VSP2, and the reaction process of the test material I was simulated; when the reaction exotherm ended, the experiment was stopped and the maximum reaction temperature Tf reached at the end of the reaction was obtained; (b) removing the material after the test in step (a) from the discharge-design adiabatic calorimeter VSP2, performing solid-liquid separation to obtain a recovered catalyst, and then mixing the recovered catalyst with the hydrogenation reaction feed to prepare a test material II containing the recovered catalyst and the hydrogenation reaction feed; The material II to be tested is measured and added into a high-pressure reactor. After the temperature and pressure are increased, the material II to be tested reacts. After the reaction is completed, the system is depressurized and cooled. The reaction system was calorimetrically tested using a fully automatic reaction calorimeter RLe to obtain the specific heat release q of the reaction; (c) re-weighing the prepared test material I and adding it to the autoclave, and reacting the test material I according to the reaction conditions of step (b); after the reaction is completed, the system is depressurized and cooled; The reaction system was calorimetrically tested using a fully automatic reaction calorimeter RLe to obtain the specific heat release Q and specific heat capacity Cp. Based on the test results of steps (a), (b) and (c), it is determined that the hydrogenation reaction catalyst is completely deactivated. The temperature at which the hydrogenation catalyst is completely deactivated is determined to be the highest reaction temperature Tf reached at the end of the reaction exotherm in step (a).

2. The method according to claim 1, characterized in that The hydrogenation reaction raw materials are selected from one or more of aniline, p-aminotoluene, m-phenylenediamine, o-phenylenediamine, p-chloroaniline, m-phenylenediamine and p-phenylenediamine.

3. The method according to claim 2, characterized in that The hydrogenation reaction raw materials are selected from one or more of aniline, p-aminotoluene, m-phenylenediamine, p-chloroaniline and m-xylylenediamine.

4. The method according to claim 1, wherein The hydrogenation catalyst is selected from one or more of Pd / C, Pt / C, Ru / C, Rh / C, Pd / Al2O3, Pt / Al2O3, Ru / Al2O3, Rh / Al2O3, Co / Al2O3 and Ni / Al2O3.

5. The method according to claim 4, characterized in that The hydrogenation catalyst is selected from one or more of Pd / C, Co / Al2O3, Ru / Al2O3, Pt / Al2O3 and Ni / Al2O3.

6. The method according to claim 1, characterized in that In the material to be tested I, the content of the hydrogenation catalyst is 0.1-0.8wt%, based on the weight of the hydrogenation reaction raw materials contained in the material to be tested I.

7. The method according to claim 6, characterized in that In the material to be tested I, the content of the hydrogenation catalyst is 0.3-0.6wt%, based on the weight of the hydrogenation reaction raw materials contained in the material to be tested I.

8. The method according to claim 1, characterized in that The reaction steps in step (a) are: Add 20-50 g of the test material I to a 110 ml test cell, then replace the gas with nitrogen 3-5 times; heat the system at a rate of 2-6 K / min to 50-150° C.; when the reaction temperature stabilizes, pressurize the system to 1-8 MPa of hydrogen; then allow the system to react, releasing heat upon initiation; when the rate of temperature rise is ≤0.2° C. / min, the reaction exotherm ends, and the experiment is stopped, with the temperature cooled to room temperature; Obtain the maximum reaction temperature Tf reached by the system at the end of the reaction.

9. The method according to claim 8, characterized in that In step (a), the amount of the material I to be tested is 30-40 g; The temperature rise rate of the system is 3-5K / min; Heat the system to 80-120°C; When the system is pressurized, the hydrogen pressure rises to 3-6 MPa; When the temperature rise rate is ≤0.1℃ / min, the reaction exotherm ends and the experiment is stopped.

10. The method according to claim 8, characterized in that In step (a), the reaction system is stirred using a magnetic stirrer at a stirring speed of 100-500 rpm.

11. The method according to claim 10, characterized in that In step (a), the reaction system is stirred using a magnetic stirrer at a stirring speed of 200-400 rpm.

12. The method according to claim 1, characterized in that The reaction steps in step (b) are: The material II to be tested was added into a 2L autoclave in an amount of 500-1000 g; the atmosphere was then replaced with nitrogen 3-5 times; the system was heated to 50-150°C; when the reaction temperature stabilized, a pre-calibration was performed, and then the system was pressurized to 2-8 MPa of hydrogen; the system was then reacted for 2-6 h, and a post-calibration was performed after the reaction was completed. Finally, the temperature was lowered and the pressure was released, and the experiment was stopped.

13. The method according to claim 12, characterized in that In step (b), the amount of the test material II added is 600-800 g; When heating the system, the temperature is raised to 80-120°C; When the system is pressurized, the hydrogen pressure rises to 4-6 MPa; The reaction time of the system is 3-5h.

14. The method according to claim 12, characterized in that In step (b), the reaction system is stirred using a self-priming stirring paddle at a stirring speed of 600-1200 rpm.

15. The method according to claim 14, characterized in that In step (b), the reaction system is stirred using a self-priming stirring paddle at a stirring speed of 800-1000 rpm.

16. The method according to any one of claims 1 to 15, characterized in that The steps for determining whether the hydrogenation reaction catalyst is completely deactivated include: (1) Based on the highest reaction temperature Tf reached by the system at the end of the reaction measured in step (a), calculate the adiabatic temperature rise: Adiabatic temperature rise = Tf - Tp, where Tp is the reaction temperature in step (a); (2) Calculating the ratio q / Q of the reaction specific heat release q and the reaction specific heat release Q measured in steps (b) and (c); (3) Based on the reaction specific heat release Q and specific heat capacity Cp measured in step (c), calculate the adiabatic temperature rise of the main reaction: Adiabatic temperature rise of the main reaction = Q / Cp; (4) When Tf-Tp≤Q / Cp and q / Q≤2%, it is judged that the hydrogenation catalyst has been completely deactivated. The temperature at which the hydrogenation catalyst is completely deactivated is determined to be the highest reaction temperature Tf reached at the end of the reaction exotherm.

17. The method according to claim 16, characterized in that In step (4), when Tf-Tp≤Q / Cp and q / Q≤1%, it is determined that the hydrogenation catalyst has been completely deactivated, and the temperature at which the hydrogenation catalyst is completely deactivated is determined to be the highest reaction temperature Tf reached when the reaction exotherm ends.