JP6492814B2 - Catalytic reaction production system with catalyst life analyzer - Google Patents

Description

  The present invention is based on a production apparatus using a fixed bed flow-type catalytic reaction, an apparatus for accumulating the production amount, an apparatus for detecting the temperature of the catalyst layer when the catalyst is used, and the total amount of the target product within the catalyst use period. A device for calculating a change in activation energy for a change in catalyst performance, a calculation device for analyzing a change in the catalyst performance over time from the change in the activation energy, and a calculation device for predicting the catalyst layer temperature from the change in the catalyst performance over time The present invention relates to a catalytic reaction production system including a catalyst life analysis apparatus for a chemical reaction process using a catalyst.

  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 consisting of a fixed bed flow type reaction tower, it is necessary to replace the catalyst by judging that the stage where the activity of the catalyst has been reduced to the minimum necessary level is the catalyst life.

  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, the catalyst life is estimated in advance, the next replacement period is planned, and the production plan is made so that the catalyst activity does not decrease to the minimum necessary level and the maximum catalyst performance is exhibited until that time. Establishing is an important technical issue.

  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 demand for a catalytic reaction production system including a catalyst life analysis apparatus for a chemical reaction process using a catalyst capable of optimizing operating conditions according to a production plan.

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 Predict the catalyst life and plan the next replacement period, and follow the production plan so that the catalyst activity does not decrease to the minimum necessary level until the replacement period is reached and the maximum catalyst performance is exhibited. The present invention provides a catalytic reaction production system equipped with a catalyst life analysis apparatus for chemical reaction processes using a catalyst capable of optimizing operating conditions.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a target product within a catalyst use period in a production apparatus based on a fixed bed flow-type catalytic reaction and a chemical reaction process using a catalyst. A catalyst equipped with a catalyst life analysis device that calculates a change in catalyst performance as a change in activation energy based on the total amount of catalyst, and predicts a catalyst life by analyzing a change in the catalyst performance over time from the change in the activation energy A reaction production system was found and the present invention was completed.

  In other words, the present invention relates to a production apparatus based on a fixed bed flow type catalytic reaction and a chemical reaction process using a catalyst. The present invention relates to a catalytic reaction production system equipped with a catalyst life analysis apparatus that can calculate the amount of the catalyst and predict the catalyst life by analyzing the change in the catalyst performance with time from the amount of change in the activation energy.

  Hereinafter, the present invention will be described in detail.

  The catalytic reaction production system of the present invention comprises a production apparatus using a fixed bed flow-type catalytic reaction, an apparatus for accumulating the total amount of the target product, an apparatus for detecting the catalyst layer temperature when the catalyst is used, and an object within the catalyst use period. A device that calculates the amount of change in activation energy based on the total amount of products, an arithmetic unit that analyzes changes in catalyst performance over time from the amount of change in activation energy, and predicts catalyst layer temperature from changes in catalyst performance over time A catalyst life analysis apparatus for a chemical reaction process using a catalyst having an arithmetic unit is provided.

  The production apparatus by the fixed bed flow type catalytic reaction of the present invention is a production apparatus by the fixed bed flow type catalytic reaction in which the catalyst to be used is filled in the reaction tube and the raw material is supplied to the catalyst bed. Can be used.

  The apparatus for accumulating the total amount of products targeted by the present invention is an apparatus for determining by analyzing the amount of product flowing out from the outlet of a fixed bed flow type reaction tower. The total amount of the target product within the use period can be obtained by recording the measured target product amount every unit time and integrating the product amount within the use period.

  The apparatus for detecting the temperature of the catalyst layer when using the catalyst of the present invention 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 apparatus for calculating the amount of change in activation energy based on the total amount of the target product within the catalyst use period of the present invention is an object accumulated by the apparatus for accumulating the total amount of the target product within the use period. The calculation device calculates the amount of change in activation energy for each position of the catalyst layer based on the total amount of products.

  The arithmetic device for analyzing the change in the catalyst performance with time from the change amount of the activation energy according to the present invention is based on the change amount of the activation energy at each position of the catalyst layer calculated by the device for calculating the change amount of the activation energy. This is an arithmetic unit that analyzes the change in the catalyst performance with time at each position of the layer using the reaction rate constant according to the Arrhenius equation.

  The calculation device for predicting the catalyst layer temperature from the change in catalyst performance with time according to the present invention uses the reaction rate constant according to the Arrhenius equation calculated by the calculation device for analyzing the change in catalyst performance with time from the amount of change in activation energy. And an arithmetic unit for predicting the catalyst layer temperature by calculating according to the mass balance.

  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 the total amount of the target product within the period of use of the catalyst, W is a constant indicating the degree of deterioration of the catalyst, and the reaction tube is filled with the catalyst in the reaction tower. Equation (1) as a function of L and W, where L _{0 is} the length to the outlet and L is the position from the inlet of the reaction tube;
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.

  Further, when the reaction raw material generates a reaction product at the reaction rate calculated in the catalyst layer at the reaction tube inlet, 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. By repeating this, it is possible to predict all the catalyst bed temperatures from the reaction tube inlet to the outlet.

  From the predicted distribution of the catalyst layer temperature, it is possible to analyze the influence on the reaction tower due to a decrease in catalyst performance. Further, by comparing the predicted value of the calculated catalyst layer temperature with the actual temperature measured by the catalyst layer temperature detecting means for detecting the catalyst layer temperature when the catalyst is used, the catalyst life prediction for predicting this catalyst life is performed. The accuracy of the method and the catalyst life analysis apparatus using this prediction method can be known.

  Furthermore, in the arithmetic unit that predicts the catalyst layer temperature from the change in the catalyst performance over time, the operation of the catalyst does not decrease to the minimum necessary level until the planned replacement time is reached, and the maximum catalyst performance is exhibited. Future predictions of catalyst bed temperature can be made to search for and optimize conditions.

  The catalytic reaction production system of the present invention is a catalytic reaction production system comprising a catalyst life analysis apparatus for a chemical reaction process that analyzes a change in catalyst performance with time from the amount of change in activation energy as described above and predicts a catalyst life. Based on a fixed bed flow-type catalytic reaction device, a device for accumulating the total amount of the target product, a device for detecting the temperature of the catalyst layer when the catalyst is used, and the total amount of the target product within the catalyst use period. In addition, an apparatus for calculating the amount of change in activation energy, an arithmetic unit for analyzing the change in catalyst performance with time from the amount of change in activation energy, and a catalyst having an arithmetic unit for predicting the catalyst layer temperature from change with time in catalyst performance were used. It is a catalytic reaction manufacturing system provided with a catalyst life analysis apparatus for chemical reaction processes.

  With the catalytic reaction production system equipped with such a catalyst life analysis device capable of predicting the catalyst life, the operating conditions of the production device can be optimized according to the production plan so as to exhibit the maximum catalyst performance.

  For example, if it is predicted that the production amount according to the production plan cannot be obtained in the future prediction when the operation is continued according to the operation condition of the current manufacturing equipment, the production amount must be increased by changing the operation condition. . At that time, analyzing the future prediction when the operating conditions are changed by the catalyst life analyzer, searching for the optimal operating conditions, and changing the operating conditions of the manufacturing equipment to those conditions, the production volume according to the production plan can be It is possible to obtain an efficient production utilizing the catalytic performance.

  Alternatively, search for possible operating conditions for the reaction tower, predict the catalyst layer temperature in the future, and reset the operating conditions if it is determined that the production volume according to the production plan cannot be obtained. The information necessary for analyzing the change in the catalyst performance with time is re-input to the apparatus for inputting the information, and recalculated. Even if recalculation is performed in this manner, if it is determined that it is no longer possible to obtain a production amount according to the production plan within the range of operating conditions in which the reaction column is possible, the catalyst life is determined.

  Therefore, if the time determined to be the catalyst life as described above is set as the next replacement time, the catalyst activity will not be reduced to the minimum required level until that time and the maximum catalyst performance will be exhibited. It is possible to make a production plan.

  In addition, if the production equipment continues to operate under the current operating conditions until the next replacement time, the catalyst life will be reached, and if the operation cannot be continued, the operating conditions will be changed by the catalyst life analyzer so that the manufacturing equipment can continue to be operated until the next replacement time. By analyzing the future predictions in this case, searching for the optimal operating conditions and changing the operating conditions of the manufacturing equipment to those conditions, the catalyst packed in the reactor of the manufacturing equipment will reach the catalyst life until the next replacement time. It is possible to adjust the production efficiently so that the production volume during the period cannot be maintained.

  Further, the catalyst life analysis apparatus may include means for outputting the analysis result and means for recording the analysis result.

  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 results includes the information necessary for the analysis and the catalyst layer temperature predicted from the change in the catalyst performance with time and the change in the catalyst performance with time at each position of the catalyst layer obtained by the analysis. Is a device for recording on a computer-readable recording medium storing the.

  The “recording medium” here 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 catalytic reaction production system equipped with a catalyst life analysis apparatus for chemical reaction processes using chemistry using the catalyst according to the present invention is particularly suitable for a process for producing 1,2-dichloroethane by reacting ethylene, hydrogen chloride and oxygen. Can be used.

  By using a catalytic reaction production system equipped with a catalyst life analysis apparatus for a chemical reaction process using a catalyst according to the present invention, a plan for the next catalyst replacement time can be determined efficiently, and the activity of the catalyst is maintained until the replacement time is reached. The operating conditions can be optimized so that the catalyst performance is maximized without lowering to the minimum required level.

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 catalyst life analyzer 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 catalyst life analysis device of the oxychlorination reactor according to the present invention after continuing the operation conditions of FIG. 3 for one year with the actually measured temperature in the reaction tube. FIG. 5 shows the output from the catalyst life analyzer of the oxychlorination reactor according to the present invention when the operating conditions are changed in order to obtain the same production volume as in FIGS. It is a figure of the temperature distribution in a reaction tube and the operation upper limit temperature.

  The catalyst life analysis apparatus using the oxychlorination reaction production system according to the present invention will be described based on an actual use example.

  The oxychlorination apparatus constituting the oxychlorination reaction production system is equipped with a fixed bed flow type reaction tower, and a 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. Then, the temperature distribution curve obtained by actual measurement and simulation after one year progress after continuous operation is 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. Further, FIG. 5 shows a temperature distribution curve obtained by simulation after two years, assuming continuous operation. Although the operating conditions were changed so that the same production amount as in FIGS. 3 and 4 could be maintained, the operating upper limit temperature was not lowered and the catalyst life was determined to be two years.

  In this way, by actively utilizing the temperature analysis information, the catalyst life is estimated in advance, the next catalyst replacement period is planned, and the activity of the catalyst does not decrease to the minimum necessary level until that time, In addition, the production plan can be made so that the maximum catalyst performance can be exhibited, and the catalyst can be used effectively.

Claims (5)

Based on the production equipment by fixed bed flow-type catalytic reaction, the equipment that accumulates the total amount of the target product, the device that detects the temperature of the catalyst layer when using the catalyst, the total amount of the target product during the catalyst use period A device for calculating a change amount of activation energy, a calculation device for analyzing a change in catalyst performance with time from the change amount of activation energy, and a calculation device for predicting a catalyst layer temperature from a change with time in catalyst performance, wherein the catalyst is used The change amount ΔEa of the activation energy after the elapse of the period is expressed as follows: W is 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, L _{0 is} the length of the reaction tube, If the position from the entrance is L, 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)
A catalytic reaction production system comprising a catalyst life analysis apparatus for a chemical reaction process using a catalyst characterized by being represented by: 2. The change in catalyst performance with time is analyzed by calculating a reaction rate constant k after the period of use from the change amount ΔEa of activation energy and comparing it with an initial reaction rate constant k _0. The catalytic reaction production system described. 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 catalytic reaction production system according to claim 2, wherein The catalytic reaction production system according to any one of claims 1 to 3, wherein a catalyst layer temperature predicted from changes in operating conditions and catalyst performance is used for determination of life prediction. The catalytic reaction production system according to any one of claims 1 to 4, wherein the chemical reaction process using a catalyst is a process of producing 1,2-dichloroethane by reacting ethylene, hydrogen chloride and oxygen.

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