JP6565237B2 - Method for analyzing catalyst performance over time and device for analyzing catalyst performance over time - Google Patents

Description

  In the present invention, in a chemical reaction process using a catalyst, the change in the activation energy is calculated based on the total amount of the target product during the catalyst use period, and the change in the catalyst performance with time is analyzed. The present invention relates to a catalyst performance aging analysis method and a catalyst performance aging analysis apparatus that can be used.

  Among the methods for producing vinyl chloride monomer (VCM), a method called a balanced oxychlorination process, that is, (1) production of 1,2-dichloroethane (EDC) by direct chlorination of ethylene, (2) A process comprising VCM production by EDC thermal decomposition reaction and (3) EDC production by ethylene oxychlorination reaction is widely adopted in the petrochemical industry.

  Among these, the EDC production method by the oxychlorination reaction of ethylene is a chemical reaction process using a catalyst. The air method uses air as the oxygen raw material used for the reaction, and a small amount of molecular oxygen is added to the air. An oxygen enrichment method to be used and an oxygen method using molecular oxygen as an oxygen source are known.

  In general, the performance (activity) of a catalyst decreases with time. Therefore, in a chemical reaction process using a catalyst composed of a fixed bed flow type reaction tower, it is necessary to replace all of the catalyst at a stage where the activity of the catalyst has been reduced to a necessary minimum level.

  Usually, the catalyst replacement time is determined in advance, and the production is continued with the catalyst whose performance has deteriorated without performing the catalyst replacement during the planned production period. This is because unplanned catalyst replacement is very costly and labor-intensive for replacement work, and the loss due to production cuts while the equipment is stopped. Therefore, it is an important technical problem to make a production plan so that the catalyst activity does not decrease to the minimum necessary level until the planned replacement time is reached and the maximum catalyst performance is exhibited.

  It is disclosed that a simulation technique is used for this problem.

  For example, a simulation method for hydrodesulfurization reaction is disclosed (see Patent Document 1). However, in this method, since a factor is experimentally determined for the deterioration of the catalyst, the life of the catalyst cannot be predicted with high accuracy when the operating conditions change.

  Also, a reformer simulator is disclosed (see Patent Document 2). This method is a simulator that takes into account the deterioration of the life of the catalyst, but this simulator is for training the operator and does not predict the actual operating state of the apparatus.

  A method by simulation is disclosed for the purification process (Patent Documents 3 to 4). This method is a method for optimizing the purification conditions by paying attention to the deterioration phenomenon of the catalyst due to the deposition of carbon and metal in the catalyst pores in the hydrorefining reaction. However, it is not effective at all for reactions where the volume of carbonaceous and metal is not responsible for catalyst degradation.

  Since the oxychlorination catalyst reaction is an exothermic reaction, the temperature of the catalyst layer increases with the generation of heat, and a rapid decrease in catalyst performance occurs particularly at hot spots where the temperature has increased.

  As a method of analyzing thermal degradation, a method by simulation is disclosed for an exhaust gas purification catalyst of an automobile (Patent Documents 5 to 6). In order to analyze the thermal deterioration of the catalyst, these are methods in which the time during which the catalyst is exposed to a high temperature and the degree of deterioration are correlated in advance and analyzed as the deterioration rate of the catalyst. The deterioration rate obtained by this method is an average value obtained by collectively analyzing the decrease in the overall catalyst performance from the inlet to the outlet.

  In a fixed bed flow reaction tower such as a chemical reaction process using an oxychlorination catalyst, temperature distribution is generated in the catalyst layer due to heat generation from the reaction bed inlet to the outlet, which is not uniform. Therefore, the performance degradation of the catalyst is not uniform from the inlet to the outlet. Using such a catalyst whose performance deterioration varies depending on the position of the catalyst layer and optimizing the production by performing simulation technology to optimize the operating conditions cannot meet the requirement at all with the information on the average value of the catalyst performance.

  Like the chemical reaction process using a catalyst consisting of such a fixed bed flow type reaction tower, even if the catalyst performance drop is different at the position of the catalyst layer, the performance of the catalyst at each position can be analyzed accurately. There is a need for a time-change analysis method and a catalyst performance time-change analysis apparatus that optimizes operating conditions and enables production adjustment.

US Pat. No. 5,341,313 Japanese Examined Patent Publication No. 7-108372 Japanese Patent No. 3,931,083 Japanese Patent No. 4,612,006 Japanese Patent No. 3,135,499 Japanese Patent No. 4,747,984

  Even if the performance degradation of the catalyst is not uniform at the position of the catalyst layer as in the chemical reaction process using a catalyst consisting of a fixed bed flow type reaction tower, the catalyst performance at each position is analyzed Until the planned replacement time is reached, the catalyst activity will not decrease to the minimum required level, and the operating conditions will be optimized so that the maximum catalyst performance will be exhibited, allowing the production to be adjusted over time. It is an object of the present invention to provide an analysis method and a catalyst performance aging analysis apparatus.

  As a result of intensive studies to solve the above problems, the present inventors have found that the amount of change in activation energy based on the total amount of the target product within the catalyst use period in the chemical reaction process using the catalyst. As a result, the inventors have found a catalyst performance aging analysis method and a catalyst performance aging analysis apparatus that can analyze the catalyst performance aging from the activation energy change amount, and have completed the present invention.

  That is, according to the present invention, in a chemical reaction process using a catalyst, the amount of change in activation energy is calculated based on the total amount of the target product within the period of use of the catalyst, and the catalyst performance is calculated from the amount of change in activation energy. The present invention relates to a catalyst performance aging analysis method and a catalyst performance aging analysis apparatus capable of analyzing a aging change.

  Hereinafter, the present invention will be described in detail.

  The catalyst performance aging analysis method and the catalyst performance aging analysis apparatus according to the present invention provide a total amount of a target product within a catalyst use period in a chemical reaction process using a catalyst including a fixed bed flow type reaction tower. The present invention is a catalyst performance change analysis method and a catalyst performance change analysis device that calculates a change in activation energy based on the activation energy and analyzes a change in catalyst performance over time from the change in activation energy. .

  The present inventor has organized the catalyst performance degradation phenomenon based on the reaction kinetics, and found that the performance degradation is caused by a change in activation energy. That is, when the activation energy of the catalyst having different use periods was measured separately for each position of the reaction tube, a change as shown in FIG. 1 was confirmed. This is a change based on the change over time of the catalyst, and the change was modeled. Based on this model, the amount of change in activation energy is calculated based on the total amount of the target product within the catalyst use period, and the amount of change in activation energy is arranged based on the reaction kinetics, thereby obtaining a catalyst. Changes in performance over time can be analyzed. Since the amount of change in the obtained activation energy is not uniform at the position of the catalyst layer and can be calculated with a different value for each position, it is possible to analyze the change in the catalyst performance with time for each position.

The amount of change ΔEa of the activation energy is W for the total amount of the target product within the period of use of the catalyst, K is a constant indicating the degree of deterioration of the catalyst, and it is exited from the inlet of the reaction tube filled with the catalyst in the reaction tower. Where L _{0 is} the length up to and L is the position from the inlet of the reaction tube, Equation (1) as a function of L and W;
ΔEa (L, W) = KW ⁿ × (L−L ₀ ) (1)
(Where n is greater than 0 and less than 1)
It is represented by KW ^{n in} equation (1) is a value corresponding to the slope of a straight line having the slope of FIG.

As shown in FIG. 1, assuming that the slope is expressed as a function of W, Step 1: The start point M advances in the L direction on the unused Ea line (broken line in FIG. 1) along with the start of use of the catalyst. A straight line is drawn in the direction. Procedure 2: ΔEa rises from the entrance to M, and ΔEa is obtained from Equation (1), assuming that ΔEa remains unchanged from M to the exit (ie, ΔEa = 0). By examining the relationship between the obtained inclination and W, the change of the inclination with respect to W can be given as a function. When the slope is plotted as shown in FIG. 2 to obtain the relationship with W, it can be approximated to KW ⁿ , where n is greater than 0 and less than 1, and n in the example shown in FIG. 2 is 0.5. It was. The movement of M can be expressed by a function having W as a variable. When D is a constant, it can be approximated to DW ^m , where m is 0 to 1.

When analyzing the change in catalyst performance with time using the change amount of the activation energy, a reaction rate constant according to the Arrhenius equation can be generally used. Assuming that the reaction rate constant after the period of use is k, the frequency factor is A, the initial activation energy is Ea ₀ , the gas constant is R, and the catalyst layer temperature is T (L, W), it is a function of L and W. Formula (2);
k (L, W) = Aexp (− (Ea ₀ + ΔEa (L, W)) / RT (L, W)) (2)
It is represented by

It can be analyzed the time course of catalyst performance by comparing with the reaction rate constant k and the initial reaction rate constant k _0.

  The catalyst performance aging analysis apparatus using the catalyst performance aging analysis method for analyzing the aging change of the catalyst performance from the activation energy change amount as described above is used for the target product within the period of use of the catalyst. Means for integrating the total amount, catalyst layer temperature detecting means for detecting the catalyst layer temperature when the catalyst is used, and calculating means for calculating the change amount of the activation energy based on the total amount of the target product within the catalyst use period. Prepare.

  Hereinafter, in a chemical reaction process using a catalyst consisting of a fixed bed flow-type reaction tower, the amount of change in catalyst performance is activated based on the total amount of the target product within the catalyst use period and the catalyst layer temperature after the use period. The means for calculating a catalyst performance change-over-time analysis apparatus using a catalyst performance change-over-time analysis method for calculating a change in activation energy and analyzing a change in catalyst performance over time from the change in activation energy The part will be described.

  The catalyst layer temperature detection means for detecting the catalyst layer temperature when the catalyst is used is an apparatus for measuring the temperature of the catalyst layer installed in the fixed bed flow type reaction tower. The measured temperature of the catalyst layer is recorded for each position of the catalyst layer and every elapsed time.

  The means for measuring the total amount of the target product within the period of use of the catalyst is an apparatus for determining by analyzing the amount of product flowing out from the outlet of the fixed bed flow type reaction tower. By recording the measured product amount every unit time and integrating the product amount within the use period, the total amount of the target product within the use period can be obtained.

  The calculation means for calculating the change amount of the activation energy based on the total amount of the target product within the catalyst use period is the product measured by the means for measuring the total amount of the target product within the use period. The calculation unit includes a calculation unit that calculates the change amount of the activation energy based on the total amount and the calculation unit that analyzes the change in the catalyst performance with time from the change amount of the activation energy. Furthermore, a means for inputting information necessary for analyzing the change with time, a means for outputting the analysis result of the change with time, and a means for recording the analysis result may be provided.

  The means for inputting information necessary for analyzing the change in the catalyst performance with time is an operating condition for controlling the fixed-bed flow reaction tower used for the calculation to the calculation means for calculating the change amount of the activation energy, It is an apparatus for inputting information on the temperature of the catalyst layer during operation, the total amount of the target product within the period of use, and the physical properties and properties of the catalyst.

  The change amount of the activation energy is calculated by the calculation unit that calculates the change amount of the activation energy based on the total amount of the product measured by the apparatus that measures the total amount of the target product within the period of use. ) For each position of the catalyst layer. The time-dependent change in the catalyst performance at each position of the catalyst layer calculated from the change in the activation energy at each position of the catalyst layer calculated by the calculation unit that analyzes the change in the catalyst performance with time from the amount of change in activation energy. Analysis is performed using the constant equation (2).

  In the catalyst layer at the inlet of the reaction tube, when the reaction raw material generates a reaction product at the calculated reaction rate, reaction heat is generated according to the reaction amount. This reaction heat is removed from the reaction tube, or moves to the next catalyst layer together with the flowing gas. The temperature of the next catalyst layer is determined by this heat balance and mass balance, and the reaction rate can be calculated. Therefore, by repeating this calculation, it is possible to display the change in the catalyst performance with time as the catalyst layer temperature distribution from the reaction tube inlet to the outlet.

  By comparing the calculated catalyst layer temperature distribution with the measured temperature measured by the catalyst layer temperature detecting means for detecting the catalyst layer temperature when the catalyst is used, this time-dependent analysis method of the catalyst performance and this analysis method were used. It is possible to know the accuracy of the catalyst performance change analyzer over time. The means for outputting the analysis result is an apparatus for outputting the catalyst layer temperature predicted from the time-dependent change of the catalyst performance and the time-dependent change of the catalyst performance at each position of the catalyst layer obtained by the analysis.

  The means for recording the analysis result includes the time-dependent analysis program for the information necessary for the analysis, the catalyst performance at each position of the catalyst layer obtained by the analysis, and the catalyst layer temperature predicted from the catalyst performance with time. Is a device for recording on a computer-readable recording medium storing the.

  As used herein, “recording medium” means a computer-readable medium capable of recording a program. For example, a semiconductor memory, an IC card, an optical disk, a magnetic disk, a magneto-optical disk, a magnetic tape, a digital video disk, and the like are included.

  The aging analysis method and the catalyst performance aging analysis apparatus according to the present invention can be suitably used particularly for a process for producing 1,2-dichloroethane by reacting ethylene, hydrogen chloride and oxygen.

  By using the temporal change analysis method and the catalyst performance temporal change analysis apparatus according to the present invention, the catalyst performance deterioration is not uniform at the position of the catalyst layer as in the chemical reaction process using the catalyst, and differs depending on the position. Even in such a case, the catalyst performance at each position is analyzed and the operating conditions are optimized so that the catalyst activity does not decrease to the minimum necessary level until the planned replacement time is reached and the maximum catalyst performance is exhibited. Can be made.

FIG. 1 is a diagram showing a change in activation energy measured separately for each position of a reaction tube of a catalyst having a different use period. FIG. 2 is a graph in which the slope obtained from FIG. 1 is plotted against the total amount W of the target product within the period of use. FIG. 3 is a diagram comparing the temperature distribution in the reaction tube output from the time-dependent change analysis apparatus of the oxychlorination reactor according to the present invention and the actually measured temperature in the reaction tube. FIG. 4 is a diagram comparing the temperature distribution in the reaction tube output from the time-dependent change analysis device of the oxychlorination reactor according to the present invention after continuing the operation conditions of FIG. 1 for one year with the actually measured temperature in the reaction tube.

  A time-dependent change analysis apparatus for catalyst performance using the oxychlorination reactor according to the present invention will be described based on an actual use example.

  The oxychlorination reactor is equipped with a fixed bed flow type reaction tower, and the catalyst is packed in the reaction tower. In order to analyze this catalyst, the area from the inlet to the outlet of the reaction tube is divided into 100 and displayed.

  The raw material gas containing air as ethylene, hydrogen chloride, and oxygen raw material is supplied in its entirety from the inlet of the reaction tube, and when the raw material gas passes through the catalyst layer, reaction heat corresponding to the raw material conversion amount is generated by the reaction. The reaction is carried out in such a way that unreacted raw materials and products flow out from the outlet while changing the temperature. The reaction rate of each section divided by 100 using the formula (1) and the formula (2) is obtained, the reaction heat is calculated from the reaction amount in the section, and the temperature of the catalyst layer is calculated. The temperature distribution of the 100 catalyst layers predicted in this way is as shown in FIG. It can be seen that the measured temperature shown in FIG. 3 is in good agreement with the temperature distribution curve obtained by simulation. Thereafter, the measured temperature after one year of continuous operation and the temperature distribution curve obtained by simulation are shown in FIG. As shown in FIG. 4, it can be seen that the measured temperature is in good agreement with the temperature distribution curve obtained by simulation even after one year. Thus, the fact that the actual measurement value and the result of the simulation are in good agreement indicates that the models of the equations (1) and (2) are appropriate. By actively utilizing such temperature analysis information, the operating conditions of the catalyst are not reduced until the planned replacement time is reached, so that the catalyst activity does not decrease to the minimum necessary level and the maximum catalyst performance is exhibited. By optimizing, the catalyst can be used effectively. In addition, since the reaction tower has an upper limit temperature limit, it is possible to set in advance a suitable temperature distribution curve accompanying catalyst deterioration in consideration of the catalyst activity and the temperature limit of the reaction tower.

Claims (8)

In a chemical reaction process using a fixed bed flow type reaction catalyst, the activation energy is calculated when calculating the change in activation energy based on the total amount of the target product within the period of use of the fixed bed flow type reaction catalyst. variation DerutaEa, W the total amount of the desired product in the life of a fixed bed flow reaction catalyst, a constant indicating the degree of deterioration of a fixed bed flow reaction catalyst K, the length of the reaction tube L ₀ , where L is the position from the inlet of the reaction tube, ΔEa is a function of L and W, equation (1);
ΔEa (L, W) = KW ⁿ × (L−L ₀ ) (1)
(Where n is greater than 0 and less than 1)
Aging analysis method of a fixed bed flow reaction catalyst performance is calculated, and wherein the analyzing changes over time of a fixed bed flow reaction catalyst performance from a change amount of the activation energy using. The reaction rate constant k after the period of use is calculated from the change amount ΔEa of the activation energy, and the change over time of the catalyst performance for the fixed bed flow type reaction is analyzed by comparing with the initial reaction rate constant k ₀ The method for analyzing changes over time in the catalyst performance for a fixed bed flow-type reaction according to claim 1. Assuming that the frequency factor is A, the initial activation energy is Ea ₀ , the gas constant is R, and the catalyst layer temperature is T (L, W), the reaction rate constant k is a function of L and W (2);
k (L, W) = Aexp (− (Ea ₀ + ΔEa (L, W)) / RT (L, W)) (2)
The time-dependent analysis method of the fixed bed flow-type reaction catalyst performance according to claim 2, wherein Chemical reaction process using a fixed bed flow reaction catalyst, ethylene, process der to produce 1,2-dichloroethane by reacting hydrogen chloride and oxygen is, a fixed bed flow reaction catalyst for the oxychlorination reaction aging analysis method of the catalyst performance for a fixed bed flow type reaction according to any one of the catalyst der Ru claims 1-3. Means for integrating the total amount of the target product, means for detecting the catalyst layer temperature when using the fixed bed flow type reaction catalyst, and the total amount of the target product within the fixed bed flow type reaction catalyst use period. comprises means for calculating a change amount of the activation energy on the basis of the purpose of the variation ΔEa fixed bed flow activation energy after reaction catalyst use period elapses, the period of use of a fixed bed flow reaction catalyst A function of L and W, where W is the total amount of products, K is a constant indicating the degree of deterioration of the fixed bed flow reaction catalyst, L _{0 is} the length of the reaction tube, and L is the position from the reaction tube inlet. As formula (1);
ΔEa (L, W) = KW ⁿ × (L−L ₀ ) (1)
(Where n is greater than 0 and less than 1)
The time-dependent change analysis apparatus of the catalyst performance for chemical reaction processes using the fixed bed flow-type reaction catalyst characterized by the above-mentioned. The reaction rate constant k after the period of use is calculated from the change amount ΔEa of the activation energy, and the change over time of the catalyst performance for the fixed bed flow type reaction is analyzed by comparing with the initial reaction rate constant k ₀ A time-dependent change analysis apparatus for catalyst performance for a chemical reaction process using the fixed bed flow-type reaction catalyst according to claim 5. Assuming that the frequency factor is A, the initial activation energy is Ea ₀ , the gas constant is R, and the catalyst layer temperature is T (L, W), the reaction rate constant k after the period of use is a function of L and W. (2);
k (L, W) = Aexp (− (Ea ₀ + ΔEa (L, W)) / RT (L, W)) (2)
The time-dependent change analysis apparatus of the catalyst performance for chemical reaction processes using the fixed bed flow-type reaction catalyst of Claim 6 characterized by these. Ethylene fixed bed flow reaction process using a reaction catalyst, the process der to produce 1,2-dichloroethane by reacting hydrogen chloride and oxygen is, a fixed bed flow reaction catalyst for the oxychlorination reaction aging analyzer catalytic performance for chemical reaction process using a fixed bed flow type reaction catalyst according to any one of the catalyst der Ru claim 5-7.

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