JP2009149531A - Method for controlling temperature in reactor, reaction apparatus and manufacturing method of dimethyl ether - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance controllability of the temperature in a reactor and the conversion rate in the synthesis of dimethyl ether from, for example, methanol by an equilibrium reaction involving an exothermic reaction. <P>SOLUTION: A plurality of catalyst layers are provided in a reactor, and quenching zones for cooling a mixture containing methanol and dimethyl ether are provided between the catalyst layers. A fluid containing at least either one of dimethyl ether and water generated together with dimethyl ether is supplied as a quenching fluid into the quenching zone. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temperature control method and a reaction apparatus inside a reactor, and a method for producing dimethyl ether, which are performed when a raw material is supplied to an adiabatic reactor and an object is produced by an equilibrium reaction accompanied by heat generation.

  In a production plant, a catalyst layer may be provided in a reactor, and raw materials may be allowed to flow through the reactor to react to obtain a product that is a reaction product. One of the important operating conditions for allowing the reaction to proceed appropriately in the reactor is temperature management in the reactor. Generally, in order to adjust the temperature in the reactor so as to be a temperature suitable for the reaction, the raw material is adjusted to a preset temperature and then supplied to the reactor.

  When the above reaction is an exothermic reaction, the temperature of the raw material increases as the raw material flows downstream through the reactor, that is, as the reaction proceeds. If the temperature of the raw material is higher than the temperature range suitable for the main reaction, undesirable by-products (impurities) are generated, resulting in loss of the raw material or deterioration of the catalyst due to the promotion of coking. Since the yield decreases when the temperature of the raw material falls below the above temperature range, various methods for maintaining the temperature in the catalyst layer within the target temperature range have been proposed. The following method is known as a typical example for maintaining the temperature in such a reactor.

  FIG. 14 shows a multitubular reactor 100, in which a raw material is supplied into a plurality of pipes 101 suspended in the multitubular reactor 100, a reaction is performed in the pipe 101, and the pipe 101 is externally connected. It is comprised so that it may cool with a refrigerant | coolant. In this multitubular reactor 100, the raw material can be reliably and quickly cooled, but a large amount of refrigerant is required, and the structure of the reactor 100 is complicated, which increases the cost of the apparatus. It is not suitable for enlargement.

  FIG. 15 shows an apparatus in which a plurality of reactors 102 are connected and a heat exchanger (intermediate heat exchanger) 103 is interposed between the reactors 102 and 102. In this apparatus, the raw material supplied into the first-stage reactor 102 generates heat by reaction in the first-stage reactor 102, and then cooled by the heat exchanger 103, and then the second-stage reactor 102, and the reaction proceeds in the second-stage reactor 102. Thereafter, although not shown, the raw material is further supplied to the third and subsequent reactors via a heat exchanger. In such a configuration, in order to increase the controllability of the temperature in the reactor 102, it is necessary to increase the number of the reactors 102 and the heat exchanger 103, and connection piping is also required. The cost increases and the device configuration becomes complicated. Further, in such a heat exchanger 103, the raw material before the reaction before being supplied to the first-stage reactor 102 is often used as the refrigerant for heat exchange, and heat is exchanged with the reaction product. The subsequent raw material is supplied to the first-stage reactor 102. In such a case, there is a problem that the temperature at the outlet of the reactor 102 affects the temperature at the inlet of the reactor 102 and it becomes difficult to control the temperature in the reactor 102.

  Therefore, Patent Document 1 divides a catalyst layer in a fixed bed flow type adiabatic reactor into a plurality of layers, and provides a quench zone for cooling the raw material between the layers, and in this quench zone a quench fluid As a method, a raw material is supplied in a liquid state and the inside of the reactor is cooled. In this apparatus, when the heated raw material is supplied from the upper side, an exothermic reaction proceeds in the upstream catalyst layer, and the temperature of the raw material rises. The raw material is cooled by the quench fluid in the quench zone, and then flows to the downstream catalyst layer and reacts in the same manner. The flow rate of the quench fluid is adjusted so that the temperature of the raw material is measured at the lower side of the quench zone after the quench fluid is supplied, and the temperature of this portion is in a temperature range suitable for the main reaction.

  Since this apparatus is composed of one reactor and does not require a heat exchanger, the cost can be reduced. In addition, when an inert component is used as the quench fluid, it is necessary to purify and separate the inert component, but since the raw material is used, there is an advantage that such an operation becomes unnecessary.

By the way, as an example of the above-described equilibrium reaction with exotherm, for example, in a reactor for producing dimethyl ether from methanol, when the outlet temperature of the reactor is slightly higher than the temperature during normal operation, a side product is generated due to an undesirable side reaction. Things are generated. Therefore, it is necessary to stabilize the temperature in the reactor.
In the reactor described in Patent Document 1, the supply amount of the quench fluid is adjusted based on the temperature on the inlet side of the downstream catalyst layer, and the internal temperature of the reactor is controlled. Therefore, it is difficult to make the temperature on the inlet side constant, and the temperature change on the inlet side cannot be avoided due to factors such as the temperature change of the raw material.

Under such circumstances, when the raw material is supplied as a quench fluid as in Patent Document 1, the raw material increases, and the equilibrium is biased toward the reaction product side. For this reason, since the reaction rate changes sensitively to the temperature change at the inlet side of the catalyst layer, the influence of the temperature at the inlet side of the catalyst layer on the temperature at the outlet side of the reactor becomes large, resulting in the temperature at the outlet of the reactor. As the fluctuation width of the material increases, the change in the conversion rate also increases. For this reason, the temperature at the outlet of the reactor becomes too high, and a by-product due to an undesirable side reaction is generated, the purity of the product is lowered, or the temperature at the outlet of the reactor becomes too low. The yield to be obtained cannot be obtained.
Therefore, there is a demand for a technique that can control the temperature in the reactor by a simple method in a reactor having a simple configuration that can be increased in size.

JP 2004-298768 (paragraphs 0014, 0020, 0021)

  The present invention has been made under such circumstances. The purpose of the present invention is to supply raw materials to an adiabatic reactor and to produce the target product by an equilibrium reaction with exotherm in the reactor. An object of the present invention is to provide a technique for improving the controllability of the temperature in the vessel to suppress the production of by-products due to a temperature rise and the reduction in yield due to the temperature drop.

The temperature control method inside the reactor of the present invention is as follows.
Dividing the reaction area into multiple parts, the divided reaction areas are assigned to one or more adiabatic reactors, the raw materials are supplied into the adiabatic reactors, and the target product is obtained by an equilibrium reaction with exotherm. In the temperature control method performed when manufacturing
Supplying a raw material to the first-stage reaction region to obtain a reaction product containing a target product;
Next, a step of sequentially supplying a mixture of the reaction product taken out from the reaction region on the front stage side and the unreacted raw material to the reaction region on the rear stage side to obtain a reaction product containing the target product;
Supplying a quench fluid to the mixture at at least one location between the reaction zones and cooling the mixture by mixing; and
The quench fluid includes at least one of a part of the reaction product obtained in the reaction region downstream of the quench fluid supply region and the same compound as the target product obtained in other than the adiabatic reactor. It is characterized by including.

The quench fluid may contain a part of the reaction product after cooling the reaction product obtained in the final-stage reaction region.
Each of the plurality of reaction regions is preferably constituted by a catalyst layer.
It is preferable that the number of the divided reaction regions is three.
The cooling step is preferably performed by adjusting at least one of the supply amount, composition, and temperature of the quench fluid.

  The equilibrium reaction with exotherm may be a reaction that uses methanol as a raw material to obtain a reaction product composed of water and the target dimethyl ether. In that case, it is preferable that the quench fluid includes any one of dimethyl ether and a mixed fluid of dimethyl ether and water.

The reaction apparatus of the present invention comprises:
In a reactor for supplying a raw material into an adiabatic reactor and producing a target product by an equilibrium reaction with exotherm,
One or two or more adiabatic reactors, each of which is divided into a plurality of reaction zones and to which a plurality of divided reaction zones are assigned;
Means for supplying the raw material to the first stage reaction zone;
The quench fluid is supplied to and mixed with a mixture of the reaction product and the unreacted raw material, which is interposed in at least one place between the reaction regions and is taken out from the reaction region on the preceding stage side. A quench zone for cooling;
The quench zone is a fluid containing at least one of a part of the reaction product obtained in the reaction zone downstream of the quench zone and the same compound as the target product obtained in other than the adiabatic reactor. And means for supplying to the apparatus.

The reactor is
A cooling means for cooling the reaction product obtained in the final stage reaction zone,
The quench fluid is preferably a fluid containing a part of the reaction product after being cooled by the cooling means.
Each of the plurality of reaction regions is preferably constituted by a catalyst layer.
It is preferable that the number of the divided reaction regions is three.
In addition, the reaction apparatus of the present invention preferably includes a control unit that adjusts at least one of the supply amount, composition, and temperature of the quench fluid and supplies the quench fluid to the quench zone. .

  The equilibrium reaction with exotherm may be a reaction that uses methanol as a raw material to obtain a reaction product composed of water and the target dimethyl ether. In that case, it is preferable that the quench fluid includes any one of dimethyl ether and a mixed fluid of dimethyl ether and water.

The method for producing dimethyl ether of the present invention comprises:
Dividing the reaction area into multiple parts, the divided reaction areas are assigned to one or more adiabatic reactors, supplying methanol into the adiabatic reactors, and producing dimethyl ether by dehydration condensation reaction In the method
Supplying methanol to the first stage reaction zone to obtain a reaction product comprising dimethyl ether and water;
Next, a step of sequentially supplying a mixture of the reaction product extracted from the reaction zone on the front stage side and unreacted methanol to the reaction zone on the rear stage side to obtain a reaction product consisting of dimethyl ether and water;
Supplying a quench fluid to the mixture at at least one location between the reaction zones and cooling the mixture by mixing; and
The quench fluid includes at least one of dimethyl ether and water obtained in a reaction region downstream of the quench fluid supply region, and dimethyl ether obtained outside the adiabatic reactor. Features.

The cooling step is preferably performed by adjusting at least one of the supply amount, composition, and temperature of the quench fluid.
The quench fluid is preferably obtained in the last-stage reaction zone and contains either dimethyl ether or water after cooling.
Each of the plurality of reaction regions is preferably constituted by a catalyst layer.
It is preferable that the number of the divided reaction regions is three.
The quench fluid is preferably a part of dimethyl ether after removing water and unreacted methanol which are by-products mixed in dimethyl ether.

  According to the present invention, the reaction region is divided into a plurality of regions, and the plurality of divided reaction regions are assigned to one or more adiabatic reactors, and the raw materials are supplied into the adiabatic reactors to generate heat. In producing the target product by the accompanying equilibrium reaction, a mixture comprising the reaction product containing the target product obtained by supplying the raw material to the first stage reaction zone and the unreacted raw material is converted into the first stage. A reaction product containing the target product is obtained by sequentially supplying from the reaction region to the reaction region on the downstream side, and at least at one point between the reaction regions, the reaction product obtained on the downstream side of the reaction region is obtained. The mixture obtained by cooling at least one of the same compounds as the quenching fluid is supplied to the object obtained in a part other than the adiabatic reactor. Therefore, the amount of the reaction product in the mixture increases, the equilibrium is biased toward the raw material side, and the reaction progresses gently, so that the change in the reaction rate due to the temperature change on the inlet side of the reaction region is small. As a result, the controllability of the temperature in the reactor is improved, and the generation of unplanned by-products due to the temperature rise and the yield reduction due to the temperature drop can be easily suppressed.

  An embodiment of a reaction apparatus of the present invention and a temperature control method using this apparatus will be described with reference to FIGS. FIG. 1 shows an overview of a manufacturing plant including a reaction apparatus 2 for manufacturing a target product. The reaction apparatus 2 includes a vertical reactor 20 which is, for example, a fixed bed flow type adiabatic reactor. One end side of a raw material gas supply pipe 20a, which is a means for supplying a raw material, is connected to the top of the reactor 20 and the other end side of the raw material gas supply pipe 20a is connected to a heat exchanger 2a and an evaporator. The raw material storage source 4 in which the liquid raw material is stored is connected via 2b. The evaporator 2b is for vaporizing a liquid raw material to obtain a raw material gas.

  One end of the product gas outflow pipe 20b is connected to the bottom of the reactor 20, and the heat exchanger 2a is connected to the product gas outflow pipe 20b. In this heat exchanger 2a, the raw material is heated and the mixture is cooled and heated between the raw material in the raw material gas supply pipe 20a and the mixture of the reaction product and raw material in the product gas outflow pipe 20b. It is configured to be exchanged. The other end side of the product gas outflow pipe 20b is connected to a side wall of a first distillation column 30 described later.

  Inside the reactor 20, a reaction region necessary for obtaining a desired reaction yield, for example, a catalyst layer 22 is divided into an upstream side and a downstream side. One catalyst layer 22a is formed as a first reaction region, and the downstream reaction region is formed as a second reaction region by a second catalyst layer 22b. These catalyst layers 22 (22a, 22b) are supported by a support 23 in which a number of gas supply holes (not shown) are formed.

  A quench zone Q for cooling the mixture in the reactor 20 with a quench fluid is provided in a region between the first catalyst layer 22a and the second catalyst layer 22b in the reactor 20. A quench fluid supply pipe 24 that is a means for supplying a part of the reaction product as a quench fluid to the quench zone is connected to the side surface of the reactor 20 in the quench zone Q. In the vicinity of the first catalyst layer 22a on the upper side of the quench zone Q in the reactor 20, the reactor 20 is connected to a spray section 24a in which a plurality of discharge holes 24b for uniformly supplying the quench fluid is formed. Yes.

Further, a temperature detection unit 29 is provided on the side surface of the reactor 20, and one end side thereof protrudes into the reactor 20, and the temperature of the mixture cooled in the quench zone Q is, for example, the upper part of the second catalyst layer 22b. It is configured to detect in the vicinity of the side. The control unit 3 is connected to the temperature detection unit 29, and the control unit 3 uses the flow rate adjustment valve 27 described later to make the temperature of the source gas suitable for the reaction based on the temperature detected by the temperature detection unit 29. The flow rate of the quench fluid is controlled to be in the temperature range.
At the subsequent stage of the reactor 20, there is provided equipment for taking out the target reaction product from the mixture obtained from the reactor 20 and supplying a part of it to the reactor 20 as a quench fluid. For example, equipment including two distillation columns 30 and 40 for obtaining dimethyl ether as a target product is provided.

  The first distillation column 30 is for separating and purifying a target product from a mixture of unreacted raw materials and reaction products, and a target product take-out pipe 31 as a cooling means is connected to the top of the column. The one end side of the discharge pipe 32 is connected to the lower end portion. The object discharged from the object take-out pipe 31 is taken out of the system as a product. A part of the object is branched from the object take-out pipe 31, and the quench fluid supply pipe 24 described above is used as the quench fluid. It is configured to be returned to the quench zone Q. A flow rate adjustment valve 27 is interposed in the quench fluid supply pipe 24.

  The other end side of the aforementioned discharge pipe 32 is connected to the side wall of the second distillation column 40. The second distillation column 40 is for separating and purifying unreacted raw material from the mixture from which the target product has been removed in the first distillation column 30. One end of a raw material discharge pipe 41 is provided at the top of the column. The discharge pipe 42 is connected to the lower end portion. The other end side of the raw material discharge pipe 41 is connected to the above-described raw material gas supply pipe 20a on the upstream side of the evaporator 2b, and is configured to return the unreacted raw material for reuse. The discharge pipe 42 is for discarding by-products and impurities remaining after the target product and unreacted raw materials are removed from the mixture, and these are discharged out of the system.

Subsequently, a method of operating the above-described reaction apparatus 2 will be described with reference to FIGS. 1 and 2.
The liquid raw material composed of one substance or a plurality of substances is vaporized in the evaporator 2b provided in the previous stage, and the unreacted raw material and reaction product taken out from the reactor 20 in the heat exchanger 2a. Heat exchange is performed with the mixture consisting of and heated to a temperature T1.
Thereafter, the source gas is supplied to the reactor 20 through the source gas supply pipe 20a, and flows in the reactor 20 from the top to the bottom. Then, a reaction product containing the target product is generated by the equilibrium reaction of the following formula (1) in the first catalyst layer 22a, and a gas of a mixture containing the reaction product and an unreacted raw material gas; Become.
Source gas ⇔ Reaction product (target product (+ by-product)) + heat of reaction (1)

Due to the reaction heat generated at this time, the temperature of the gas in the mixture rises to a temperature T2.
When dimethyl ether is produced, methanol, which is a liquid raw material, is vaporized, and dimethyl ether and water are generated in the first catalyst layer 22a by an equilibrium reaction of the following formula (2).
2CH3OH ＣＨ CH3OCH3 + H2O + ΔH (2)
ΔH = −23.4 kJ / mol

Subsequently, when quench fluid is supplied from the spray section 24a in the quench zone Q, the quench fluid and the gas of the mixture that has become a high temperature (T2) due to the exothermic reaction of the previous catalyst layer 22a are mixed together, and the temperature of the mixture is reduced. T3. This quench fluid is a fluid composed of a part of the reaction product obtained by the reaction apparatus 2, and is supplied in a liquid state or a gaseous state. When producing dimethyl ether, the quenching fluid is, for example, gaseous dimethyl ether.
By supplying a part of the reaction product as a quench fluid in this way, the amount of the reaction product on the right side of the above formulas (1) and (2) increases in the second catalyst layer 22b. Since the equilibrium reactions of the formulas (1) and (2) are biased toward the raw material side and the reaction for producing the target product is suppressed, the above reaction proceeds gently.

The gas of the mixture thus cooled, more specifically the mixture containing the quench fluid, is supplied to the second catalyst layer 22b, and a reaction product is gently generated by the same reaction in the second catalyst layer 22b. Go. The mixture composed of the reaction product and the unreacted raw material rises to a temperature T4 due to the reaction heat generated by the reaction in the second catalyst layer 22b.
Thereafter, the mixture is taken out from the reactor 20 through the product gas outflow pipe 20b, and heat exchange is performed with the raw material in the heat exchanger 2a.

  Then, the flow after this will be described taking the case of producing dimethyl ether as an example. A mixture of dimethyl ether as a reaction product discharged from the reactor 20 and water and methanol as an unreacted raw material is a first distillation. It is supplied to the column 30 to separate and purify the target dimethyl ether. The dimethyl ether separated and purified from the mixture is taken out from the target take-out pipe 31, dissipates heat to the pipe wall of the target take-out pipe 31, and becomes a temperature equal to or lower than the aforementioned temperature T2, and a part thereof is the quench fluid supply pipe 24. Is returned to the reactor 20 as a quench fluid. The remaining dimethyl ether is taken out of the system as a product.

  The mixture from which the dimethyl ether has been removed is discharged from the lower side of the first distillation column 30 and supplied to the second distillation column 40, where methanol, which is an unreacted raw material, is separated and purified in the second distillation column 40. The As described above, the unreacted raw material is returned to the raw material gas supply pipe 20a and is supplied again to the reactor 20 together with the raw material supplied from the raw material storage source 4. In addition, waste, which is a by-product from which the target product and unreacted raw materials have been removed, in this example, water is discharged out of the system.

  Here, the temperature T3 at the entrance of the catalyst layer 22b is detected by the temperature detection unit 29, and the supply flow rate of the quench fluid is controlled via the control unit 3 and the flow rate adjustment valve 27 in accordance with the detected temperature value. Although the inlet temperature T3 of the catalyst layer 22b is stabilized, it is inevitable that the inlet temperature T3 varies within a certain fluctuation range. However, in the present invention, since the reaction product is used as the quench fluid, as described above, since the equilibrium reaction is biased toward the raw material side and the reaction in which the target product is generated is suppressed, the outlet temperature T4 of the catalyst layer 22b is suppressed. The influence of the inlet temperature T1 of the catalyst layer 22a is reduced. That is, since the change in the reaction rate to the target product is small with respect to the change in the inlet temperature T1 of the catalyst layer 22a, the change in the outlet temperature T4 of the catalyst layer 22b becomes insensitive and the fluctuation width of the conversion rate becomes small.

  According to the above-described embodiment, when the raw material is supplied into the adiabatic reactor 20 and the target product is produced by the equilibrium reaction accompanied by heat generation, the first reaction region and the second reaction region for performing the reaction of the raw material are performed. A quench zone Q is provided between the reaction zone and the quench zone Q, and a part of the reaction product taken out from the second reaction zone is cooled and supplied as a quench fluid to the quench zone Q. The resulting mixture is cooled. Therefore, as already described in detail, the amount of the reaction product in the mixture is increased, the equilibrium is biased toward the raw material side, and the reaction proceeds gently. Therefore, temperature control in the reactor 20 becomes easy, As a result, generation of unplanned by-products due to temperature rise can be suppressed, and reduction in yield due to temperature decrease can be suppressed. Furthermore, catalyst coking can be suppressed and the catalyst life can be extended. Furthermore, the rapid temperature rise (runaway reaction) in the reaction apparatus 2 can be suppressed, and the reaction apparatus 2 can be operated safely. Therefore, the configuration of the reactor 20 can be simplified as compared with the existing method, the size can be easily increased, and the number of parts constituting the reactor 20 can be reduced.

  The quench fluid may be a gas or a liquid. When using a gaseous quench fluid, the latent heat of vaporization cannot be used, so it is necessary to increase the amount of supply compared to the case of using a liquid, but the amount of reaction products in the reactor 20 increases, so that the reaction The effect of suppressing the speed is great. On the other hand, when a liquid quench fluid is used, the temperature of the mixture can be lowered with a smaller supply amount than when a gas is used. For example, when the supply amount of the raw material is small and the temperature rise of the mixture due to the reaction is small, the reaction product may be supplied as a quench fluid without cooling. Even in such a case, the amount of the reaction product in the reactor 20 is increased, so that the reaction rate can be suppressed.

  In the above example, two catalyst layers 22 are used. However, as shown in FIGS. 3 and 4, for example, there may be more catalyst layers. FIG. 3 shows a reactor 20 having three catalyst layers (22a, 22b, 22c) and FIG. 4 having five catalyst layers (22a, 22b, 22c, 22d, 22e). 3 and 4, the temperature of the mixture is detected by the temperature detection unit 29 in the quench zone Q between the catalyst layers 22, and the flow rate of the quench fluid supplied from the spray unit 24 a is adjusted. Even in such a reactor 20, the reaction proceeds in a state where the reaction rate is suppressed by the quench fluid as in the above example. Thus, the effect similar to said example is acquired by making the catalyst layer 22 into multiple layers.

  In addition to the case where a plurality of catalyst layers 22 are provided in one reactor 20, as shown in FIGS. 5 and 6, for example, a plurality of reactors 20 provided with one catalyst layer 22 are connected. You may do it. FIG. 5 and FIG. 6 show examples in which three and five such reactors 20 are connected, respectively, and a quench fluid supply pipe 24 is provided in the product gas outflow pipe 20b connecting the reactors 20 to each other. Is connected. Further, in addition to such a reactor 20, for example, as shown in FIGS. 7 and 8, a plurality of reactors 20 provided with at least one catalyst layer 22 may be connected in combination. FIG. 7 shows an example in which a reactor 20 provided with one catalyst layer 22 and a reactor 20 provided with two catalyst layers (22a, 22b) are connected in series. FIG. 8 shows an example in which a reactor 20 provided with two catalyst layers (22a, 22b) and a reactor 20 provided with three catalyst layers (22a, 22b, 22c) are connected in series. . Similarly, a quench fluid is supplied between the catalyst layers 22 in the quench zone Q. Even in such a configuration, the same effect as the above example can be obtained.

  In each of the above examples, it is preferable to provide the quench zone Q between all of the catalyst layers 22, 22. However, for example, when the temperature fluctuation is small, the number of quench zones Q may be reduced. It is sufficient if there is at least one quench zone Q. FIG. 9 shows an example in which the quench zone Q between the second catalyst layer 22b and the third catalyst layer 22c from the upstream side is omitted from the reactor 20 shown in FIG. 4 described above. In such a reactor 20, the same effect can be obtained.

  In the above example, the target in the system is used as the quench fluid. However, the same compound as the target outside the system can be used as the quench fluid. As such an example, as shown in FIG. 10, for example, a plurality of reaction apparatuses 2 may be provided, and the quench fluid may be supplied from one reaction apparatus 2 to the other reaction apparatus 2. In such a case, the quench fluid supply pipe 24 of the other reactor 2 is connected to the object take-out pipe 31 of one reactor 2. In addition, in the above FIGS. 3-10, about the same structure as FIG. 1, the same code | symbol is attached | subjected. An unreacted raw material may be mixed in the target object which is the quench fluid.

Further, in addition to using the target product as the quench fluid, for example, when a reaction product (by-product) other than the target product is generated from the raw material (in addition to the target product, the substance generated on the right side of the formula (1) In some cases, the reaction product may be used as a quench fluid. For example, in a reaction to obtain dimethyl ether, water may be used as the quench fluid. In that case, as shown in FIG. 11, the entire amount of the target object is extracted from the target object extraction pipe 31, and a part of the waste is returned to the quench zone Q as a quench fluid. Also in this case, the reaction is suppressed by increasing the reaction products on the right side of the formulas (1) and (2) as in the above example. The fluctuation of the temperature of the mixture in is reduced. In FIG. 11, the same components as those in FIG.
In addition, you may use a target object with this by-product as a quench fluid, For example, in reaction which obtains dimethyl ether from methanol, you may use a dimethyl ether and water as a quench fluid. Further, dimethyl ether from outside the system may be used as a quench fluid.

  In each of the above examples, the same out-of-system compound as the reaction product and target product was used as the quench fluid, but the same out-of-system compound as the reaction product and target product was included to the extent that the reaction rate was suppressed. If so, this quench fluid may contain unreacted raw materials. In that case, for example, in FIG. 1, one end side of a branch pipe (none of which is shown) provided with a valve is connected to the raw material discharge pipe 41, and the other end side of this branch pipe is connected to the quench fluid supply pipe 24. The unreacted raw material may be positively used as a part of the quench fluid by adjusting the opening of the valve.

  Further, in each of the above examples, the flow rate of the quench fluid is controlled by the control unit 3 to stabilize the inlet temperature T3 of the reactor 20, but the flow rate of the quench fluid is made constant and the control unit 3 is used. For example, by adjusting the opening degree of the aforementioned branch pipe valve and the flow rate adjusting valve 27, the ratio of the reaction product contained in the quench fluid and the compound outside the same system as the target product, that is, the composition of the quench fluid is adjusted. Thus, the inlet temperature T3 may be stabilized. In addition, a cooling mechanism (not shown) is provided in the quench fluid supply pipe 24, the quench fluid flow rate is made constant, and the temperature of the quench fluid is adjusted via the control unit 3, whereby the inlet temperature T3 of the reactor 20 is set. You may make it stabilize. Furthermore, the inlet temperature T3 of the reactor 20 is stabilized by adjusting the flow rate of the quench fluid, the composition of the quench fluid, and the temperature of the quench fluid in combination through the control unit 3. Also good.

  As described above, the temperature control method and reaction apparatus for the target product of the present invention produce the target product by an equilibrium reaction with exotherm, as described above, for example, synthesis reaction of dimethyl ether by dehydration from methanol in the examples described later, It may be applied to ammonia synthesis reaction from nitrogen and nitrogen. In addition to the synthesis reaction, the reaction may be applied to an equilibrium reaction with exotherm such as an oxidation reaction, a hydrogenation reaction, or other reaction, or may be applied to these reactions in a liquid phase.

Experiments conducted to confirm the effect of the method of the present invention will be described below. In this example, an experiment was conducted in which methanol was used as the raw material, and dimethyl ether was obtained as a target product by an equilibrium reaction accompanied by heat generation in the above-described formula (2).
In addition, standard conditions are set in each of the following experiments. In this standard conditions, the conversion rate of methanol at the final catalyst layer outlet and the temperature at the outlet of each catalyst layer are set to be equal under the respective standard conditions. It is a condition.

Example 1
As an apparatus for carrying out the above reaction, a thermometer was provided at the inlet of the reactor 20 and at the inlet and outlet of each of the catalyst layers 22a and 22b, using the reactor 2 shown in FIG. .
In this reactor 2, methanol at a flow rate F1 was supplied, dimethyl ether as a quench fluid was supplied to the quench zone Q at a flow rate F2, and unreacted methanol was returned at a flow rate F3. Water as a by-product was discharged from the discharge pipe 42 described above. In addition, each flow volume F1-F3 represents the mass flow volume of each fluid.

  The experimental conditions were determined as follows so that the conversion rate and temperature of methanol at the outlet of the reactor 20 were 75% and 340 ° C., respectively, and these conditions were used as standard conditions. Further, the temperature of the raw material at the inlet of the reactor 20 was changed by 1 ° C. up and down from the above standard conditions, and the other conditions were the same as the standard conditions. In each condition, the temperature at the outlet of the reactor 20 (temperature on the outlet side of the second catalyst layer 22b) and the methanol conversion rate at the outlet of the reactor 20 were compared. The flow rate F2 of dimethyl ether that is a quench fluid and the flow rate F3 of methanol that is an unreacted raw material returned from the raw material discharge pipe 41 were set to the same flow rate as the standard condition.

(Standard conditions)
Reactor 20 inlet temperature: 279 ° C
Pressure at the inlet of the reactor 20: 1.55 MPa (gauge pressure)
Ratio of quenching amount to raw material flow rate (F2 / (F1 + F3)): 0.18
Quench dimethyl ether condition: 1.5 MPa (gauge pressure)
Dimethyl ether saturated vapor (100%)

(Experimental result)
The experimental results are shown in Table 1.
(Table 1)

  As a result, the temperature in the reactor 20 also changed according to the change in the temperature at the inlet of the reactor 20 (temperature on the inlet side of the first catalyst layer 22a). It was also found that the change in the temperature at the outlet of the reactor 20 was larger than the change in the temperature at the inlet of the reactor 20. The conversion rate increased as the temperature in the reactor 20 increased, and the conversion rate decreased as the temperature in the reactor 20 decreased.

(Comparative Example 1-1)
Subsequently, as Comparative Example 1-1, an experiment was performed by connecting the distillation columns 30 and 40 to an apparatus in which the heat exchanger 103 was interposed between the plurality of reactors 102 and 102 in FIG. 15 described above. This apparatus is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part of the same structure as above-mentioned FIG. Also in this apparatus, the temperature of the raw material of each inlet and outlet of the upstream reactor (first reactor) 102 and the downstream reactor (second reactor) 102 was measured.
In this apparatus, the raw material gas that has been vaporized in the evaporator 2 b is supplied from the supply path 200 to the heat exchanger 103, and in this heat exchanger 103, this raw material gas and the reaction in the upstream reactor 102 cause a high temperature. The mixture of the raw material and the reaction product was configured to exchange heat (cool the mixture). The raw material gas after heat exchange (heated) in the heat exchanger 103 was returned to the raw material gas supply pipe 20a on the front side of the upstream reactor 102. The flow of raw materials and reaction products other than the fluid supplied to the heat exchanger 103 was the same as that of the reactor 2 in FIG.

  Then, in the same manner as in Example 1, the following conditions were determined so that the methanol conversion rate and the raw material temperature at the outlet of the downstream reactor 102 were 75% and 340 ° C., respectively. Was the standard condition. Similarly, the temperature of the raw material at the inlet of the upstream reactor 102 was changed by 1 ° C. up and down from the standard conditions, and the other conditions were the same as the standard conditions.

  Similarly, the temperature at the outlet of the downstream reactor 102 was measured, and the conversion rate was compared. The amount of methanol returned from the raw material discharge pipe 41 was set to the same flow rate as the standard conditions. In addition, the heat exchange amount (heat transfer amount) between the quench fluid and the mixture in the heat exchanger 103 was not changed even if the temperature at the inlet of the upstream reactor 102 was changed.

(Standard conditions)
Reactor 102 inlet temperature: 279 ° C
Pressure at the inlet of the reactor 20: 1.55 MPa (gauge pressure)

(Experimental result)
The experimental results are shown in Table 2.
(Table 2)

  As a result, as in Example 1, the temperature and conversion rate of each part changed according to the temperature change on the upstream side, but the amount of change was larger than the amount of change in Example 1. From this, in Example 1, it can be seen that by using dimethyl ether as a reaction product as the quench fluid, the reaction is suppressed and the controllability of the temperature inside the reactor 20 and the conversion rate is improved.

(Comparative Example 1-2)
Next, an experiment was performed using the apparatus shown in FIG. 13 as an apparatus having the same configuration as the apparatus described in Patent Document 1 described above. This apparatus generally includes a reactor 300 having substantially the same configuration as the reactor 20 of FIG. 1, but is configured to supply a liquid raw material as a quench fluid from a raw material quench supply path 200. Yes. In FIG. 13 as well, parts having the same configuration as in FIG.

  Similarly to the above experiment, the following conditions were determined so that the methanol conversion rate and the raw material temperature at the outlet side of the reactor 300 were 75% and 340 ° C., respectively, and these conditions were used as standard conditions. Similarly, the experiment was performed by changing the temperature on the inlet side of the reactor 300 up and down by 1 ° C. Even in this case, the unreacted methanol flow rate and the quench fluid flow rate returned from the raw material discharge pipe 41 were constant. Also in this example, F1 is the methanol supply amount, F2 is the quench methanol supply amount, and F3 is the recycle methanol flow rate.

(Standard conditions)
Reactor 300 inlet temperature: 279 ° C
Pressure at the inlet of the reactor 300: 1.55 MPa (gauge pressure)
Ratio of quench amount to flow rate of raw material (F2 / (F1 + F3)): 0.09
Quenched methanol conditions: 1.6 MPa (gauge pressure), liquid at boiling point

(Experimental result)
The experimental results are shown in Table 3.
(Table 3)

  Also in this result, the temperature and the conversion rate of each part inside the reactor 300 were changed depending on the temperature at the inlet of the reactor 300. As in Comparative Example 1-1, the amount of change was the same as in Example 1. It was bigger than that.

  From the above results, when a raw material is used as the quench fluid, the equilibrium reaction is biased toward the reaction product and the reaction rate to the target product is increased, resulting in an increase in the amount of heat generated, and as a result, the reactor 20. The temperature variation of the mixture at the outlet of the reactor becomes large, but by using a part of the reaction product as a quench fluid, the reaction to the target product is suppressed, and the temperature fluctuation of the mixture at the outlet of the reactor 20 is suppressed. It was found that the width can be reduced.

(Example 2)
Next, as shown in FIG. 3 described above, an experiment was conducted to confirm how the temperature at the outlet of the reactor 20 and the conversion rate change when the catalyst layer 22 has three layers. .
In the experiment, using the reactor 20 of FIG. 3, each condition was determined as follows so that the conversion rate and temperature of methanol at the outlet of the reactor 20 were 75% and 340 ° C., respectively. Was the standard condition. In addition, the temperature of the raw material at the inlet of the reactor 20 was similarly changed up and down by 1 ° C., and the other conditions were the same as the standard conditions. And the temperature of the inlet_port | entrance of each catalyst layer 22 of the reactor 20 and the temperature of an exit were measured on each condition, and the methanol conversion rate in the exit of the reactor 20 was compared. The flow rate F2 of dimethyl ether that is a quench fluid and the flow rate F3 of methanol that is an unreacted raw material returned from the raw material discharge pipe 41 were set to the same flow rate as the standard condition.

(Standard conditions)
Reactor 20 inlet temperature: 279 ° C
Pressure at the inlet of the reactor 20: 1.55 MPa (gauge pressure)
Ratio of quenching amount to raw material flow rate (F2 / (F1 + F3)): 0.18
Quench dimethyl ether condition: 1.5 MPa (gauge pressure)
Dimethyl ether saturated vapor (100%)

(Experimental result)
The experimental results are shown in Table 4.
(Table 4)

  As a result, by using the product as a quench fluid, even if the temperature on the inlet side of the reactor 20 changes, the change in the temperature on the outlet side of the reactor 20 and the conversion rate, as in the result of Experimental Example 1. It was found that can be suppressed.

It is a schematic block diagram which shows an example of the reaction apparatus for enforcing the manufacturing method of this invention. It is the schematic which shows an example of the temperature change of the raw material in the reactor in said reactor. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is a longitudinal cross-sectional view which shows the other example of said reaction apparatus. It is the schematic which shows the apparatus used for the comparative example in the Example of this invention. It is the schematic which shows the apparatus used for the comparative example in the Example of this invention. It is the schematic which shows the conventional apparatus used for the synthesis reaction. It is the schematic which shows the conventional apparatus used for the synthesis reaction.

Explanation of symbols

2 reactor 2a heat exchanger 2b evaporator 20 reactor 22 catalyst layer 24 quench fluid supply pipe Q quench zone

Claims (20)

Dividing the reaction area into multiple parts, the divided reaction areas are assigned to one or more adiabatic reactors, the raw materials are supplied into the adiabatic reactors, and the target product is obtained by an equilibrium reaction with exotherm. In the temperature control method performed when manufacturing
Supplying a raw material to the first-stage reaction region to obtain a reaction product containing a target product;
Next, a step of sequentially supplying a mixture of the reaction product taken out from the reaction region on the front stage side and the unreacted raw material to the reaction region on the rear stage side to obtain a reaction product containing the target product;
Supplying a quench fluid to the mixture at at least one location between the reaction zones and cooling the mixture by mixing; and
The quench fluid includes at least one of a part of the reaction product obtained in the reaction region downstream of the quench fluid supply region and the same compound as the target product obtained in other than the adiabatic reactor. A method for controlling the temperature inside the reactor, comprising:   The method for controlling temperature inside a reactor according to claim 1, wherein the quench fluid includes a part of the reaction product after cooling the reaction product obtained in the reaction region of the final stage.   3. The temperature control method inside a reactor according to claim 1, wherein each of the plurality of reaction regions includes a catalyst layer.   The temperature control method inside the reactor according to any one of claims 1 to 3, wherein the divided reaction regions are three.   The temperature control inside the reactor according to any one of claims 1 to 4, wherein the cooling step is performed by adjusting at least one of a supply amount, a composition, and a temperature of the quench fluid. Method.   The temperature control inside the reactor according to any one of claims 1 to 5, wherein the equilibrium reaction accompanied by heat generation is a reaction for obtaining a reaction product comprising water and dimethyl ether which is a target product using methanol as a raw material. Method.   The method for controlling temperature inside the reactor according to any one of claims 1 to 6, wherein the quench fluid includes any one of dimethyl ether and a mixed fluid of dimethyl ether and water. In a reactor for supplying a raw material into an adiabatic reactor and producing a target product by an equilibrium reaction with exotherm,
One or two or more adiabatic reactors, each of which is divided into a plurality of reaction zones and to which a plurality of divided reaction zones are assigned;
Means for supplying the raw material to the first stage reaction zone;
The quench fluid is supplied to and mixed with a mixture of the reaction product and the unreacted raw material, which is interposed in at least one place between the reaction regions and is taken out from the reaction region on the preceding stage side. A quench zone for cooling;
The quench zone is a fluid containing at least one of a part of the reaction product obtained in the reaction zone downstream of the quench zone and the same compound as the target product obtained in other than the adiabatic reactor. And a means for supplying to the reactor. A cooling means for cooling the reaction product obtained in the final stage reaction zone,
The reaction apparatus according to claim 8, wherein the quench fluid is a fluid containing a part of the reaction product after being cooled by the cooling means.   The reaction apparatus according to claim 8 or 9, wherein each of the plurality of reaction regions includes a catalyst layer.   11. The reaction apparatus according to claim 8, wherein the number of the divided reaction regions is three.   12. The apparatus according to claim 8, further comprising a control unit that adjusts at least one of a supply amount, a composition, and a temperature of the quench fluid and supplies the quench fluid to the quench zone. The reaction apparatus according to one.   The reaction apparatus according to any one of claims 8 to 12, wherein the equilibrium reaction accompanied by heat generation is a reaction for obtaining a reaction product comprising water and a target dimethyl ether using methanol as a raw material.   14. The reaction apparatus according to claim 8, wherein the quench fluid includes any one of dimethyl ether and a mixed fluid of dimethyl ether and water. Dividing the reaction area into multiple parts, the divided reaction areas are assigned to one or more adiabatic reactors, supplying methanol into the adiabatic reactors, and producing dimethyl ether by dehydration condensation reaction In the method
Supplying methanol to the first stage reaction zone to obtain a reaction product comprising dimethyl ether and water;
Next, a step of sequentially supplying a mixture of the reaction product extracted from the reaction zone on the front stage side and unreacted methanol to the reaction zone on the rear stage side to obtain a reaction product consisting of dimethyl ether and water;
Supplying a quench fluid to the mixture at at least one location between the reaction zones and cooling the mixture by mixing; and
The quench fluid includes at least one of dimethyl ether and water obtained in a reaction region downstream of the quench fluid supply region, and dimethyl ether obtained outside the adiabatic reactor. A method for producing dimethyl ether, which is characterized.   The method for producing dimethyl ether according to claim 15, wherein the cooling step is performed by adjusting at least one of a supply amount, a composition, and a temperature of the quench fluid.   The method for producing dimethyl ether according to claim 15 or 16, wherein the quench fluid is obtained in a reaction region in a final stage and contains either dimethyl ether or water after cooling.   The method for producing dimethyl ether according to any one of claims 15 to 17, wherein each of the plurality of reaction regions includes a catalyst layer.   The method for producing dimethyl ether according to any one of claims 15 to 18, wherein the number of the divided reaction regions is three.   The quenching fluid is a part of dimethyl ether after removing water and unreacted methanol, which are by-products mixed in dimethyl ether, according to any one of claims 15 to 19. The manufacturing method of dimethyl ether of description.

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