JP6796608B2 - Metal active component concentration simulation method and metal active component concentration adjustment method in the catalyst fluidized bed for phthalic anhydride production - Google Patents

Description

The present invention relates to a method for simulating the concentration of a metal active component in a fluidized bed of a catalyst for producing phthalic anhydride and a method for adjusting the concentration of the metal active component.

Phthalic anhydride is produced, for example, by vapor-phase oxidation of naphthalene in a catalytic fluidized bed. Examples of the catalyst used in the catalyst fluidized bed in this production method include those in which a metal active component is supported on a carrier such as silicon dioxide particles (see, for example, Patent Documents 1 and 2). Examples of the metal active ingredient include vanadium compounds, potassium compounds, cesium compounds, sulfur compounds and the like.

The yield and purity of the obtained phthalic anhydride are greatly affected by the activity (catalyst activity) and fluidity of the catalytic fluidized bed in which the gas phase oxidation reaction occurs, but the concentration of the metal active component in the catalytic fluidized bed is the catalyst. It is one factor that affects the activity and fluidity of the fluidized bed. Therefore, in order to appropriately maintain and manage the activity and fluidity of the catalytic fluidized bed, it is necessary to control and adjust the concentration of the metal active component in the catalytic fluidized bed.

During the gas phase oxidation reaction, the catalyst may scatter and be discharged from the catalyst fluidized bed together with crude phthalic anhydride to the subsequent process. Therefore, the catalyst fluidized bed may be replenished with a new catalyst and the used catalyst may be extracted. The amount of catalyst in the above is adjusted at any time. The concentration of the metal active component in the catalyst fluidized bed after adjusting the amount of catalyst is the amount of each of the scattered catalyst, the new catalyst to be replenished, and the used catalyst to be extracted, and the concentration of the metal active component in each catalyst. Depends on.

In order to control and adjust the concentration of the metal active component in the catalytic fluidized bed, it is necessary to simulate and predict the transition of the concentration of the metal active component in the catalytic fluidized bed in the future, but conventionally, it is a quantitative simulation. Could not be done, only qualitative predictions were possible. Then, based on the qualitative prediction, the respective amounts of the new catalyst to be replenished and the used catalyst to be extracted, and the concentration of the metal active component in the new catalyst to be replenished were determined.

However, since it is not possible to quantitatively predict the future transition of the concentration of the metal active component by such a conventional method, the concentration of the metal active component in the catalytic fluidized bed can be stably controlled and adjusted in the future. It was difficult to do. That is, quantitatively grasp when and how much catalyst should be used in order to maintain the current concentration of the metal active ingredient or to adjust the concentration to an arbitrary concentration at a certain point in the future. Couldn't.

Japanese Unexamined Patent Publication No. 11-5031 Japanese Unexamined Patent Publication No. 2000-95775

The present invention is a simulation method capable of solving the above-mentioned problems of the prior art and quantitatively predicting the future transition of the concentration of the metal active component in the catalytic fluidized bed for producing phthalic anhydride. The challenge is to provide. Another object of the present invention is to provide a method for adjusting the concentration of the metal active component in the catalytic fluidized bed for producing phthalic anhydride.

The method for simulating the concentration of a metal active component in a catalyst fluidized layer for producing phthalic anhydride according to one aspect of the present invention is for producing phthalic anhydride in which at least one of potassium, cesium, and vanadium, which are metal active components, is supported on a carrier. This is a method of simulating the concentration of each metal active component in a future catalyst for producing phthalic anhydride in a reaction for producing phthalic anhydride by vapor phase oxidation of naphthalene in a catalyst fluidized layer having a catalyst for production.

The mass of the phthalic anhydride production catalyst present in the catalyst fluidized bed during the reaction is W1, the concentration of each metal active component in the phthalic anhydride production catalyst present in the catalyst fluidized bed during the reaction is C1, respectively, during the reaction. The mass of the phthalic anhydride production catalyst scattered in the fluidized bed of the catalyst and discharged to the subsequent step is W2, and each metal active component in the phthalic anhydride production catalyst scattered during the reaction and discharged from the fluidized bed of the catalyst to the subsequent step. The mass of the phthalic anhydride production catalyst to be replenished in the catalytic fluidized bed to supplement the anhydrous phthalic acid production catalyst scattered during the reaction and discharged from the catalytic fluidized bed to the subsequent step is W0, respectively. The concentration of each metal active component in the phthalic anhydride production catalyst to be replenished in the catalytic fluidized bed is C0, respectively, and anhydrous extracted from the catalytic fluidized bed to adjust the mass of the phthalic anhydride production catalyst in the catalytic fluidized bed. The mass of the phthalic acid production catalyst is W3, and the concentration of each metal active component in the anhydrous phthalic acid production catalyst extracted from the catalytic fluidized bed in order to adjust the mass of the anhydrous phthalic acid production catalyst in the catalyst fluidized bed. Let C3 be used, and in any of the metal active components, the relationship represented by the relational expression (1) of C2 = α · C1 + β is established between the concentration C1 and the concentration C2.

Then, the reaction is actually carried out in the catalytic fluidized bed, the concentration C1 during the reaction is measured for each metal active component, and the transition of the concentration C1 during the reaction is obtained for each metal active component. The relational expression (1) and ΔC1 = (W2, C0 + W3, C0-W2, C2), where the initial concentration C1 is C1init and the amount of change in the concentration C1 after a certain period of reaction is ΔC1, W3 = W0-W2, C1 = C3. Using the relational expression (2) of −W3 ・ C3) / W1 and the relational expression (3) of C1 = C1init + ΣΔC1, the transition of the concentration C1 from the initial stage of the reaction was simulated and calculated for each metal active component. A coefficient determination step for determining the coefficients α and β of the relational expression (1) for each metal active component and a coefficient determination step for each metal active component so that the result of the simulation calculation approximates the transition of the concentration C1 obtained in the actual measurement process. A simulation step in which the future transition of the concentration C1 is simulated and calculated for each metal active component using the relational expression (1), the relational expression (2), and the relational expression (3) determined by α and β. And, the gist is to prepare.
The "Σ" in the relational expression (3) means "sum", and the relational expression (3) means that the amount of change ΔC1 at that time is sequentially added to C1init every time the reaction occurs for a certain period of time.

The method for adjusting the concentration of the metal active component in the catalytic fluid layer for phthalic anhydride according to another aspect of the present invention is the method for simulating the concentration of the metal active ingredient in the catalytic fluid layer for phthalic anhydride according to the above aspect. The future transition of the concentration C1 is calculated by simulation for each metal active component, and based on the calculation result, the catalyst for producing phthalic anhydride that is scattered during the reaction and discharged from the catalyst flow layer to the subsequent step is supplemented. The concentration C0 of each metal active component in the catalyst for producing phthalic anhydride to be replenished in the catalyst fluidized layer is determined, and when producing phthalic anhydride, phthalic anhydride having the determined concentration C0 is produced for each metal active component. The gist is to include replenishing the catalyst for use in the catalyst flow layer.

According to the present invention, it is possible to quantitatively predict the future transition of the concentration of the metal active component in the catalytic fluidized bed for producing phthalic anhydride, so that the concentration of the metal active component in the catalytic fluidized bed can be predicted in the future. It can be stably managed and adjusted over time.

It is a conceptual diagram explaining the structure of the catalyst for producing phthalic anhydride. It is a figure explaining the structure of the catalyst fluidized bed for phthalic anhydride production, and the mode of entering and exiting a catalyst for phthalic anhydride production in a catalyst fluidized bed. It is a graph which shows the measured value of the concentration C1 of each metal active component, and the simulation calculated value when the coefficient α and β of the relational expression (1) are determined so that the result of the simulation calculation is close to the measured value. Results of simulation calculation of future transition of concentration C1 for each metal active component using the relational expression (1), the relational expression (2), and the relational expression (3) in which the coefficients α and β were determined. It is a graph which shows an example.

An embodiment of the present invention will be described in detail with reference to the drawings. In the method for simulating the concentration of metal active components in the phthalic anhydride production catalyst fluidized layer according to the present embodiment, naphthalene is vapor-phase-oxidized in the catalyst fluidized layer 10 having the phthalic anhydride production catalyst 1 to produce phthalic anhydride. This is a method of simulating the concentration of each metal active component 3 in the catalyst 1 for producing phthalic anhydride in the future in the reaction to be produced.

Further, the method for adjusting the concentration of the metal active component in the catalytic fluid layer for phthalic anhydride according to the present embodiment is based on the method for simulating the concentration of the metal active ingredient in the catalytic fluid layer for phthalic anhydride according to the above embodiment. This is a method of simulating and calculating the concentration of each metal active component 3 in the catalyst 1 for producing phthalic anhydride in the future, and adjusting the concentration of the metal active component 3 in the catalyst fluidized layer 10 based on the calculation result.

First, an example of a method for producing phthalic anhydride by vapor phase oxidation of naphthalene will be described with reference to FIGS. 1 and 2. When the particulate phthalic anhydride production catalyst 1 is charged into the reactor 12 and air is blown into the reactor 12, a catalyst fluidized bed 10 is formed, and naphthalene is charged therein. Then, as shown in the following chemical reaction formula, naphthalene (C ₁₀ H ₈ ) is vapor-phase-oxidized in the catalytic fluidized bed 10 to generate phthalic anhydride (C ₈ H ₄ O ₃ ), and the produced phthalic anhydride is produced. The acid is discharged from the catalytic fluidized bed 10 (reactor 12).
C ₁₀ H ₈ + 9 / 2O ₂ → C ₈ H ₄ O ₃ + 2CO ₂ + 2H ₂ O

The gas blown into the reactor 12 is not limited to air as long as it contains oxygen, and other types of gas may be used. For example, oxygen may be blown in, or an inert gas containing oxygen may be blown in. Examples of the inert gas include nitrogen, helium, argon and the like.

As schematically shown in FIG. 1, the catalyst 1 for producing phthalic anhydride has a metal active component 3 supported on the surface of a spherical carrier 2. At least one of potassium, cesium, and vanadium is supported on the carrier 2 as the metal active component 3. Since vanadium acts as a main catalyst and potassium and cesium act as co-catalysts, it is preferable that vanadium and at least one of potassium and cesium are supported. Further, if inconveniences such as a decrease in catalytic activity do not occur, a metal compound other than these three types may be further supported.

Vanadium is a metal active ingredient, for example, it is used in the form of such vanadium pentoxide (V 2 _{O 5).}
Potassium, which is a metal active ingredient, is used in the form of, for example, potassium sulfate (K ₂ SO ₄ ), potassium nitrate, or the like.
Cesium, which is a metal active ingredient, is used in the form of, for example, cesium sulfate (Cs ₂ SO ₄ ), cesium nitrate, or the like.

Examples of the type of carrier 2 include ceramic particles such as silicon dioxide (silica), alumina, zirconia, and titanium oxide. Among these ceramics, silicon dioxide is lightweight and has high strength, and is therefore suitable as a carrier for a catalyst for producing phthalic anhydride used in a fluidized bed.
The average particle size of the phthalic anhydride production catalyst 1 is not particularly limited, but may be, for example, 20 μm or more and 180 μm or less, and more preferably 60 μm or more and 70 μm or less. When the average particle size is within the above range, the effect of good fluidity is achieved.

When naphthalene is vapor-phase-oxidized using the catalyst flow layer 10 as described above to produce phthalic anhydride, a part of the phthalic anhydride production catalyst 1 scatters together with phthalic anhydride to flow the catalyst. It is discharged from the layer 10 (reactor 12) to a subsequent step (such as a naphthalene purification step), and the amount of the phthalic anhydride-producing catalyst 1 and the concentration of the metal active component 3 in the catalyst flow layer 10 change. Therefore, by replenishing the catalyst fluidized bed 10 of the new phthalic anhydride production catalyst 1 and extracting the used phthalic anhydride production catalyst 1 from the catalyst fluidized bed 10, phthalic anhydride in the catalyst fluidized bed 10 The amount of the acid production catalyst 1 is adjusted at any time. That is, the phthalic anhydride production catalyst 1 enters and exits the catalyst fluidized bed 10 as shown in FIG. As a result, the concentration of the metal active component 3 in the catalytic fluidized bed 10 is adjusted, and the activity and fluidity of the catalytic fluidized bed 10 are controlled and adjusted.

Then, in controlling and adjusting the concentration of the metal active component 3 in the catalytic fluidized bed 10, it is performed to predict the future transition of the concentration of the metal active component 3 in the catalytic fluidized bed 10. Then, based on the prediction, the respective amounts of the new catalyst for producing phthalic anhydride 1 to be replenished and the catalyst 1 for producing phthalic anhydride of the used product to be extracted, and the new catalyst for producing phthalic anhydride 1 to be supplemented The concentration of the metal active ingredient 3 of the above was determined.

However, in the past, quantitative simulations could not be performed, and only qualitative predictions could be made. The method for simulating the concentration of the metal active component in the catalytic fluidized bed for phthalic anhydride production according to the present embodiment can perform a quantitative simulation, and the metal active ingredient 3 in the catalytic fluidized bed 10 for phthalic anhydride production can be simulated. It is possible to quantitatively predict future changes in concentration. The simulation method according to this embodiment will be described below.

After adjusting the amount of the phthalic anhydride production catalyst 1 in the catalyst flow layer 10 as described above, the concentration of each metal active component 3 in the catalyst flow layer 10 is scattered and discharged to a subsequent step. The amount of each of the phthalic anhydride production catalyst 1, the replenished new phthalic anhydride production catalyst 1, and the extracted used phthalic anhydride production catalyst 1 and the metal active component 3 in each catalyst 1. Depends on the concentration of.

Therefore, as shown in FIG. 2, the mass of the phthalic anhydride production catalyst 1 existing in the catalyst flow layer 10 during the reaction is W1, and the phthalic anhydride production catalyst 1 existing in the catalyst flow layer 10 during the reaction. The concentration of each metal active component 3 (for example, vanadium (V), potassium (K), and cesium (Cs)) in C1 is C1, and phthalic anhydride is produced which is scattered during the reaction and discharged from the catalytic fluidized layer 10 in the subsequent step. The mass of the phthalic anhydride 1 is W2, the concentration of each metal active component 3 in the phthalic anhydride production catalyst 1 scattered from the catalyst flow layer 10 in the subsequent step is C2, respectively, and the catalyst flow is scattered during the reaction. The mass of the phthalic anhydride production catalyst 1 to be replenished in the catalyst flow layer 10 to supplement the phthalic anhydride production catalyst 1 discharged from the layer 10 in the subsequent step is W0, and the anhydrous phthalic anhydride is replenished into the catalyst flow layer 10. The concentration of each metal active component 3 in the phthalic anhydride production catalyst 1 is C0, respectively, and the phthalic anhydride production extracted from the catalyst flow layer 10 in order to adjust the mass of the phthalic anhydride production catalyst 1 in the catalyst flow layer 10. The mass of the phthalic anhydride 1 is W3, and each metal active component 3 in the phthalic anhydride production catalyst 1 extracted from the phthalic anhydride production layer 10 in order to adjust the mass of the phthalic anhydride production catalyst 1 in the catalyst flow layer 10. Let the concentration be C3. In any of the metal active components 3, the relationship represented by the relational expression (1) of C2 = α · C1 + β is established between the concentration C1 and the concentration C2.

First, the reaction is actually performed in the catalyst fluidized bed 10 and data is acquired. That is, naphthalene in the catalyst fluidized bed 10 while replenishing the catalyst fluidized bed 10 of the new phthalic anhydride production catalyst 1 and extracting the used product of the phthalic anhydride production catalyst 1 from the catalyst fluidized bed 10. The gas phase oxidation reaction is actually carried out, the concentration C1 during the reaction is measured for each metal active component 3, and the transition of the concentration C1 during the reaction is obtained for each metal active component 3 (actual measurement step). An example of the result is shown in the graph of FIG. The plot marked with ◇ in the graph of FIG. 3 shows the concentration C1 of potassium in the catalyst 1 for producing phthalic anhydride present in the catalyst fluidized bed 10 during the reaction, and the plot marked with □ also shows the concentration C1 of cesium. The plot marked with Δ also indicates the concentration C1 of vanadium.

Next, the relational expression (1) and ΔC1 =, where the concentration C1 of each metal active component 3 at the initial stage of the reaction is C1init and the amount of change in the concentration C1 after the reaction for a certain period of time is ΔC1, W3 = W0-W2, C1 = C3. (W2, C0 + W3, C0-W2, C2-W3, C3) / W1 relational expression (2) and C1 = C1init + ΣΔC1 relational expression (3) are used for each metal active component 3 from the initial reaction. The transition of the concentration C1 is calculated by simulation.

The relational expression (2) is based on the mass balance between the phthalic anhydride production catalyst 1 and each metal active component 3 when considering the entry and exit of the phthalic anhydride production catalyst 1 in the catalyst fluidized bed 10 as shown in FIG. The formula obtained.
“Σ” in the relational expression (3) means “sum”, and the relational expression (3) means that the amount of change ΔC1 at that time is sequentially added to C1init every time the reaction occurs for a certain period of time. For example, if the concentration C1 changes by ΔC1a after the reaction for a certain period of time from the initial stage of the reaction, the concentration C1 after the reaction for a certain period of time becomes C1init + ΔC1a. If the concentration C1 further changes by ΔC1b after the reaction for a certain period of time, the concentration C1 after the reaction for a certain period of time becomes C1init + ΔC1a + ΔC1b.

When the simulation calculation is performed in this way, since the coefficients α and β of the relational expression (1) are unknown, a plurality of simulation results of the transition of the concentration C1 can be obtained. Therefore, the coefficients α and β of the relational expression (1) are determined for each metal active component 3 so that the result of the simulation calculation approximates the transition of the concentration C1 acquired in the actual measurement step (coefficient determination step). An example of the result is shown in the graph of FIG. The transition of the concentration C1 of potassium, cesium, and vanadium when the coefficients α and β of the relational expression (1) are determined so that the three solid lines in the graph of FIG. 3 approximate the transition of the concentration C1 obtained in the actual measurement step. It is a simulation result of. As a result, the relational expression (1) in which the coefficients α and β are determined is obtained for each metal active component 3.

Next, the future transition of the concentration C1 is determined by using the relational expression (1), the relational expression (2), and the relational expression (3) in which the coefficients α and β are determined in the coefficient determination step. Simulation calculation is performed for each component 3 (simulation process). For example, if the final measured value of the transition of the concentration C1 acquired in the actual measurement process is C1init, the future transition of the concentration C1 following the transition of the concentration C1 acquired in the actual measurement process can be simulated and quantitatively predicted. it can. That is, it is possible to predict when and how much the concentration of each metal active component 3 will be in the future. An example of the result is shown in the graph of FIG. The three solid lines in the graph of FIG. 4 show the future transition of the potassium, cesium, and vanadium concentrations C1 predicted by the simulation calculation.

In the past, there have been attempts to perform quantitative simulations, but since simulations were performed on the assumption that C2 = C1 holds for relational expression (1), quantitative simulations could not be performed with the prior art. .. In the present invention, it is considered that the quantitative simulation can be performed by performing the simulation on the assumption that C2 = α · C1 + β holds for the relational expression (1).

Next, a method for adjusting the concentration of the metal active component in the fluidized bed of the catalyst for producing phthalic anhydride according to the present embodiment will be described. Since the future transition of the concentration C1 can be predicted by the method for simulating the concentration of the metal active component in the hydrolyzed bed for producing phthalic anhydride according to the present embodiment, the result can be used to predict the future transition of the concentration C1. The concentration of the metal active component 3 in the water can be appropriately adjusted.

First, the future transition of the concentration C1 is simulated and calculated for each metal active component 3 by the method for simulating the concentration of the metal active component in the fluidized bed of the catalyst for producing phthalic anhydride according to the present embodiment. Next, based on the calculation result, phthalic anhydride production is replenished in the catalyst fluidized bed 10 in order to supplement the phthalic anhydride production catalyst 1 scattered during the reaction and discharged from the catalyst fluidized bed 10 in the subsequent process. The concentration C0 of each metal active component 3 in the catalyst 1 is determined.

Then, a phthalic anhydride production catalyst 1 in which the concentration of each metal active component 3 is the concentration C0 determined as described above is prepared and used for the vapor phase oxidation reaction of naphthalene in the catalyst fluidized bed 10. .. That is, when phthalic anhydride is produced by performing a vapor phase oxidation reaction of naphthalene in the catalyst flow layer 10, the catalyst 1 for producing phthalic anhydride that is scattered during the reaction and discharged from the catalyst flow layer 10 in a subsequent step is supplemented. The prepared catalyst 1 for producing phthalic anhydride is used as the catalyst 1 for producing phthalic anhydride to be replenished in the catalyst fluidized layer 10.

As described above, since the future transition of the concentration of the metal active component 3 in the catalyst fluidized bed 10 for producing phthalic anhydride can be quantitatively predicted, the new catalyst 1 for producing phthalic anhydride to be supplemented can be predicted. The type (concentration of the metal active component 3) can be appropriately selected to adjust the concentration of the metal active component 3 in the catalyst fluidized bed 10 to a desired value. Therefore, the concentration of the metal active component 3 in the catalyst fluidized bed 10 can be stably controlled and adjusted in the long term in the future. As a result, deterioration of the oxidation performance of the catalytic fluidized bed 10 can be suppressed. Further, since the excessive use of the catalyst 1 for producing phthalic anhydride and the metal active component 3 can be suppressed, the basic unit of the catalyst can be reduced.

It should be noted that the present embodiment shows an example of the present invention, and the present invention is not limited to the present embodiment. In addition, various changes or improvements can be added to the present embodiment, and the modified or improved forms may be included in the present invention.
For example, in the present embodiment, the catalyst fluidized bed 10 is a one-stage fluidized bed as shown in FIG. 2, but it may be a two-stage fluidized bed in which two fluidized beds are provided in series. Good.

〔Example〕
Hereinafter, the present invention will be described in more detail with reference to Examples. First, the vapor phase oxidation reaction of naphthalene in the catalytic fluidized bed while replenishing the catalyst fluidized bed of a new phthalic anhydride production catalyst and extracting the used phthalic anhydride production catalyst from the catalytic fluidized bed. Was actually carried out, the concentration C1 during the reaction was measured for each metal active component (potassium, cesium, vanadium), and the transition of the concentration C1 during the reaction was obtained for each metal active component (actual measurement step).

The new catalyst for producing phthalic anhydride used is a carrier in which spherical silicon dioxide particles are supported with vanadium, cesium, and potassium as metal active components.
Therefore, the oxidation reaction of naphthalene was operated as follows. First, the operation was started using a new catalyst A for producing phthalic anhydride (potassium content 5% by mass, cesium content 3% by mass, vanadium content 2% by mass). As the catalyst to be replenished, a new catalyst A for producing phthalic anhydride was used.

As shown in FIG. 3, since the value of the concentration C1 of the metal active component in the catalyst fluidized bed has been on a downward trend, phthalic anhydride is replenished at the time of time T1 (T1 described on the time axis of FIG. 3). The entire amount of the acid production catalyst A was changed to a new phthalic anhydride production catalyst B (potassium content 7% by mass, cesium content 4% by mass, vanadium content 3% by mass), and the operation was continued.

After that, as shown in FIG. 3, the value of the concentration C1 of the metal active component in the catalyst fluidized bed increased, and therefore, at the time of time T2 (T2 described on the time axis of FIG. 3), phthalic anhydride to be supplemented was added. The production catalyst B was completely changed to a new catalyst A for producing phthalic anhydride (potassium content 5% by mass, cesium content 3% by mass, vanadium content 2% by mass), and the operation was continued.
The content of the metal active component in these new catalysts A and B for producing phthalic anhydride corresponds to the concentration C0.

The catalyst fluidized bed was replenished with a new catalyst for producing phthalic anhydride several times a month (the total amount in January will be described later). The mass W1 of the phthalic anhydride-producing catalyst present in the catalyst fluidized bed during the reaction is 120 to 130 tons. The mass W2 of the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed in the subsequent process was 2 t / month as determined by measurement, and the anhydrous phthalic anhydride scattered during the reaction and discharged from the catalyst fluidized bed. The concentration C2 of each metal active component in the catalyst for producing phthalic acid was determined by analysis.

The mass W0 of the new phthalic anhydride production catalyst to be replenished in the catalyst fluidized bed to supplement the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed is 4 t / month, and the catalyst. The concentration C0 of each metal active component in the new catalyst for producing phthalic anhydride replenished in the fluidized bed is as described above. As the catalyst for producing phthalic anhydride to be supplemented, the catalyst A for producing phthalic anhydride is used from the start of operation until the time T1 and after the time T2, and the catalyst B for producing phthalic anhydride is used from the time T1 to the time T2. used.

The mass W3 of the used catalyst for producing phthalic anhydride extracted from the catalyst fluidized layer in order to adjust the mass of the catalyst for producing phthalic anhydride in the catalyst fluidized layer is 2 t / month, and is in the catalyst fluidized layer. The concentration C3 of each metal active component in the used catalyst for producing phthalic anhydride extracted from the catalyst fluidized layer in order to adjust the mass of the catalyst for producing phthalic anhydride is the same as the above-mentioned concentration C1.

The results are shown in the graph of FIG. The plot marked with ◇ in the graph of FIG. 3 indicates the concentration C1 of potassium in the catalyst for producing phthalic anhydride present in the catalyst fluidized bed during the reaction, and the plot marked with □ also indicates the concentration C1 of cesium, marked with Δ. The plot of also shows the concentration C1 of vanadium.

Next, the relational expressions (1), (2), and the relational expressions (1), (2), Using (3), the transition of the concentration C1 from the initial stage of the reaction was simulated and calculated for each metal active component. When the type of the catalyst for producing phthalic anhydride to be replenished was changed, the calculation was performed on the assumption that the concentration C1, the concentration C2, and the concentration C3 fluctuate in proportion to the amount of the catalyst replenished. Then, the coefficients α and β of the relational expression (1) were determined for each metal active component so that the result of the simulation calculation approximated the transition of the concentration C1 during the reaction acquired in the actual measurement step (coefficient determination step). ).

The results are shown in the graph of FIG. The transition of the concentration C1 of potassium, cesium, and vanadium when the coefficients α and β of the relational expression (1) are determined so that the three solid lines in the graph of FIG. 3 approximate the transition of the concentration C1 obtained in the actual measurement step. It is a simulation result of. As a result, the relational expression (1) in which the coefficients α and β were determined was obtained for each metal active component. That is, the coefficient α of the relational expression (1) for potassium is 1.3 and the coefficient β is 0, the coefficient α of the relational expression (1) for cesium is 0, the coefficient β is 2.9, and for vanadium. The coefficient α of the relational expression (1) of is 2.2, and the coefficient β is 0.

Next, the future transition of the concentration C1 is determined by using the relational expression (1), the relational expression (2), and the relational expression (3) in which the coefficients α and β are determined in the coefficient determination step. Simulation calculations were performed for each component (simulation process). That is, the final measured value of the transition of the concentration C1 acquired in the actual measurement step was used as C1init, and the future transition of the concentration C1 following the transition of the concentration C1 acquired in the actual measurement step was simulated and quantitatively predicted.

At that time, a simulation calculation was performed on the assumption that a new catalyst A for producing phthalic anhydride was used as a new catalyst for producing phthalic anhydride to be replenished in the catalyst fluidized bed. That is, since the final measured value of the transition of the concentration C1 acquired in the actual measurement step is high, when the catalyst A for producing phthalic anhydride having a low concentration C0 of each metal active component is used for the purpose of gradually lowering the concentration C1. Simulation calculation was performed with the setting of. The concentration C0 of each metal active component in the catalyst for producing phthalic anhydride used is 5% by mass of potassium, 3% by mass of cesium, and 2% by mass of vanadium.

The catalyst fluidized bed for producing a new phthalic anhydride was replenished and the used catalyst for phthalic anhydride was extracted from the fluidized bed once a month. The mass W1 of the phthalic anhydride production catalyst present in the catalyst fluidized bed during the reaction was 120 t. The mass W2 of the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed is 2 t / month, and the activity of each metal in the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed. The concentration C2 of the component was determined by the relational expression (1) and α and β obtained in the coefficient determination step, and was assumed to change sequentially according to the concentration C1.

The mass W0 of a new phthalic anhydride-producing catalyst to be replenished in the catalyst fluidized bed to supplement the phthalic anhydride-producing catalyst scattered during the reaction and discharged from the catalyst fluidized bed is 5 t / month, and the catalyst flow. The concentration C0 of each metal active component in the new catalyst for producing phthalic anhydride replenished in the layer is as described above.

The mass W3 of the used catalyst for producing phthalic anhydride extracted from the catalyst fluidized layer in order to adjust the mass of the catalyst for producing phthalic anhydride in the catalyst fluidized layer is 3 t / month, and is set in the catalyst fluidized layer. The concentration C3 of each metal active component in the used catalyst for producing phthalic anhydride extracted from the catalyst fluidized layer in order to adjust the mass of the catalyst for producing phthalic anhydride was the same as the above concentration C1.

The results are shown in the graph of FIG. The three solid lines in the graph of FIG. 4 are for potassium, cesium, and vanadium predicted by simulation calculation with the setting that the catalyst for producing phthalic anhydride having a low concentration C0 of each metal active component is used from the time of the vertical broken line on the graph. This is the future transition of the concentration C1. From the graph of FIG. 4, it can be seen that the concentration C1 of potassium and cesium in the catalyst fluidized bed gradually decreases by using a catalyst for producing phthalic anhydride having a low concentration C0 of each metal active component. However, since the amount of vanadium reduced due to scattering is small, the simulation result shows that the concentration C1 hardly decreases.

In the actual production of phthalic anhydride, using the simulation results as described above, in the catalyst fluidized bed to supplement the catalyst for producing phthalic anhydride scattered during the reaction and discharged from the catalyst fluidized bed to the subsequent step. By determining the type of catalyst for producing phthalic anhydride to be supplemented with, the concentration of the metal active component in the catalyst fluidized bed can be appropriately adjusted.

1 Catalyst for producing phthalic anhydride 2 Carrier 3 Metal active ingredient 10 Catalyst fluidized bed 12 Reactor

Claims (4)

In a reaction for producing phthalic anhydride by vapor-phase oxidation of naphthalene in a catalytic flow layer having a catalyst for producing phthalic anhydride in which at least one of potassium, cesium, and vanadium, which are metal active components, is supported on a carrier. , A method of simulating the concentration of each metal active component in the catalyst for producing phthalic anhydride in the future.
The mass of the phthalic anhydride production catalyst present in the catalyst fluidized bed during the reaction is W1, and the concentration of each metal active component in the phthalic anhydride production catalyst present in the catalyst fluidized bed during the reaction. C1, respectively
The mass of the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed to the subsequent process is W2, and the mass of the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed to the subsequent process is used for producing the phthalic anhydride. The concentration of each metal active component in the catalyst is C2, respectively.
The mass of the phthalic anhydride production catalyst to be replenished in the catalyst fluidized bed to supplement the phthalic anhydride production catalyst scattered during the reaction and discharged from the catalyst fluidized bed to the subsequent step is W0, the catalyst. The concentration of each metal active component in the catalyst for producing phthalic anhydride replenished in the fluidized bed is C0, respectively.
The mass of the phthalic anhydride production catalyst extracted from the catalyst flow layer in order to adjust the mass of the phthalic anhydride production catalyst in the catalyst fluidized layer is W3, and the phthalic anhydride production catalyst in the catalyst fluidized layer is The concentration of each metal active component in the phthalic anhydride production catalyst extracted from the catalyst fluidized layer in order to adjust the mass of the production catalyst was set to C3.
In any of the metal active components, the relationship represented by the relational expression (1) of C2 = α · C1 + β is established between the concentration C1 and the concentration C2.
The reaction is actually carried out in the catalytic fluidized bed, the concentration C1 during the reaction is measured for each of the metal active components, and the transition of the concentration C1 during the reaction is obtained for each of the metal active components. Actual measurement process and
The relational expression (1) and ΔC1 = (W2 · C0 + W3 · C0), where the concentration C1 at the initial stage of the reaction is C1init and the amount of change in the concentration C1 after a certain period of time is ΔC1, W3 = W0-W2, C1 = C3. Using the relational expression (2) of −W2 ・ C2-W3 ・ C3) / W1 and the relational expression (3) of C1 = C1init + ΣΔC1, the transition of the concentration C1 from the initial stage of the reaction for each metal active component is calculated. Each simulation calculation is performed, and the coefficients α and β of the relational expression (1) are determined for each of the metal active components so that the result of the simulation calculation approximates the transition of the concentration C1 acquired in the actual measurement step. Coefficient determination process and
The future transition of the concentration C1 is described by using the relational expression (1), the relational expression (2), and the relational expression (3) in which the coefficients α and β are determined in the coefficient determination step. A simulation process that performs simulation calculations for each metal active component,
A method for simulating the concentration of a metal active component in a fluidized bed of a catalyst for producing phthalic anhydride.
The "Σ" in the relational expression (3) means "sum", and the relational expression (3) means that the amount of change ΔC1 at that time is sequentially added to C1init every time the reaction occurs for a certain period of time. .. The method for simulating the concentration of a metal active component in a fluidized bed of a catalyst for producing phthalic anhydride according to claim 1, wherein the carrier is silicon dioxide particles. The method for simulating the concentration of metal active components in a fluidized bed of a catalyst for producing phthalic anhydride according to claim 1 or 2, wherein the average particle size of the catalyst for producing phthalic anhydride is 20 μm or more and 180 μm or less. The future transition of the concentration C1 is simulated and calculated for each of the metal active components by the method for simulating the concentration of the metal active component in the catalyst fluidized layer for producing phthalic anhydride according to any one of claims 1 to 3. For the production of phthalic anhydride, which is replenished in the catalyst flow layer to supplement the catalyst for producing phthalic anhydride which is scattered during the reaction and discharged from the catalyst flow layer to a subsequent step based on the calculation result. When the concentration C0 of each metal active component in the catalyst is determined and phthalic anhydride is produced, a catalyst for producing phthalic anhydride having the determined concentration C0 for each metal active component is replenished in the catalyst fluidized layer. A method for adjusting the concentration of a metal active component in a catalyst fluidized layer for producing phthalic anhydride, which comprises the above.

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