AU2008339360B2

AU2008339360B2 - Method of regulating temperature in reaction vessel, reactor, and process for producing dimethyl ether

Info

Publication number: AU2008339360B2
Application number: AU2008339360A
Authority: AU
Inventors: Nobuyasu Chikamatsu; Shuichi Funatsu; Daigo Hirakawa; Hiroshi Kita; Koji Ooyama; Takayuki Takubo; Kohei Uchida; Yoshiyuki Watanabe
Original assignee: JGC Corp; Mitsubishi Gas Chemical Co Inc
Current assignee: JGC Corp; Mitsubishi Gas Chemical Co Inc
Priority date: 2007-12-18
Filing date: 2008-12-17
Publication date: 2013-01-31
Anticipated expiration: 2028-12-17
Also published as: JP2009149531A; JP5512083B2; AU2008339360A1; TWI421125B; MY159603A; TW200936236A; KR101242251B1; CN101903323A; KR20100087388A; WO2009078490A1

Abstract

The method aims to improve the controllability of temperature and conversion in a reaction vessel in synthesizing, e.g., dimethyl ether from methanol through equilibrium reactions accompanied by an endothermic reaction. Catalyst layers are disposed in a reaction vessel, and a quench zone for cooling a mixture comprising methanol and dimethyl ether is formed between the catalyst layers. A fluid comprising at least either of dimethyl ether and the water which has generated together with the dimethyl ether is supplied as a quench fluid to the quench zone.

Description

DESCRIPTION REACTION RATE CONTROLLING METHOD OF THE INSIDE OF REACTOR, THE REACTION APPARATUS AND THE METHOD FOR MANUFACTURING DIMETHYL ETHER Technical Field [0001] The present invention relates to a reaction rate controlling method of the inside of a reactor, a reaction apparatus and a method for manufacturing dimethyl ether to be carried out when a raw material is fed into an adiabatic reactor to manufacture an objective product by an equilibrium exothermic reaction Background [0002] In a manufacturing plant, there may be the case where a catalyst bed is provided within a reactor, and a raw material is made to flow therethrough to allow it to react, thereby obtaining a product which is a reaction product thereof. One of important operation requirements for appropriately preceding the reaction within the reactor is to control the temperature within the reactor. In general, in order to adjust the temperature within the reactor at a temperature suitable for the reaction, the raw material is adjusted at a previously set up temperature and then fed into the reactor. [0003] In the case where the foregoing reaction is an exothermic reaction, as the raw material flows within the reactor toward the downstream side, namely as the reaction proceeds, the temperature of the raw material rises. When the temperature of the raw material becomes higher than the temperature range - 1 suitable for the main reaction, an undesirable by-product (impurities) is formed which causes a loss of the raw material, or the catalyst is deactivated due to the acceleration of coking; whereas when the temperature of the raw material is lower than the foregoing temperature range, the yield is lowered. Therefore, there are proposed various methods for keeping the temperature in the catalyst bed so as to maintain within an objective temperature range. As representative examples for keeping the temperature within the reactor in such a way, the following methods are known. [0004] Fig. 14 shows a multitubular reactor 100 which is configured such that a raw material is fed into a number of tubes 101 vertically installed in the reactor 100, a reaction is carried out within these tubes 101, and the tubes 101 are cooled by a coolant from the outside. In this multitubular reactor 100, though the raw material can be cooled surely and quickly, a large amount of the coolant is necessary, and the structure of the reactor 100 is complicated. Therefore, the cost of apparatus becomes high, and furthermore, this reactor is unsuitable for realizing a large scale. [0005] Fig. 15 shows an apparatus in which plural reactors 102 are connected, and a heat exchanger (intermediate heat exchanger) 103 is installed between the reactors 102 and 102. In this apparatus, a raw material fed into the first-stage reactor 102 causes a heat generation due to a reaction within this first-stage reactor 102, and the raw material is subsequently cooled by the heat exchanger 103 and then fed into the second-stage reactor 102, whereby the reaction proceeds in this second-stage reactor 102. Thereafter, the raw material is further fed into a non-illustrated third-stage 2 reactor, et seq. via a heat exchanger. In such a configuration, in order to enhance the controllability of the temperature within the reactor 102, not only the number of each of the reactor 102 and the number of each of the heat exchanger 103 is required to be increased, but a connecting pipe and the like are necessary. Therefore, the cost of apparatus becomes high, arid the configuration of apparatus becomes complicated. Also, in this heat exchanger 103, a raw material prior to the reaction which has not been fed into the first-stage reactor 102 is frequently used as the coolant for heat exchange, and the raw material after the heat exchange with a reaction product is fed into the first-stage reactor 102. In such case, the temperature at an outlet of the reactor 102 influences the temperature at an inlet of the reactor 102. Therefore, the temperature control within the reactor 102 becomess difficult. [0006] Then, Patent Document 1 proposes a method in which a catalyst bed within an adiabatic fixed bed reactor is divided into plural ones, a quench zone for cooling a raw material is provided between the respective beds, and a raw material is fed in a liquid state as a quench fluid in this quench zone, thereby cooling the inside of the reactor. In this apparatus, when the heated raw material is fed from the upper side, an exothermic reaction proceeds in the catalyst bed on the upstream side, and the temperature of the raw material rises. The raw material is then cooled by the quench fluid in the quench zone, and thereafter, it flows into the catalyst bed on the downstream side and similarly reacts therein. The flow rate of the quench fluid is adjusted such that the temperature of the raw material is measured and maintained within the temperature range suitable for the main reaction, at the lower side of the quench zone after feeding the quench fluid. 3 [0007] This apparatus is configured of a single reactor, and a heat exchanger is not necessary, therefore, the cost can be suppressed. Also, in a case of using an inert component as the quench fluid, an operation of purification or separation of the inert component is necessary. However, as far as the raw material is utilized as a quench fluid, such an operation is not necessary, which brings a merit. [0008] Now, as to one example of the foregoing equilibrium exothermic reaction, in a reactor for manufacturing dimethyl ether from methanol, in the case where the outlet temperature of the reactor slightly rises as compared with the temperature of the normal operation, a by-product is formed due to an undesirable side reaction. For that reason, it is necessary to stabilize the temperature within the reactor. In the reactor described in the foregoing Patent Document 1, the feed amount of the quench fluid is adjusted based on the inlet temperature of next catalyst bed, thereby controlling the inside temperature of the reactor. However, in view of properties of the control system, it is difficult to make the inlet temperature constant, and in addition, because of factors such as a temperature change of the raw material, the change of the inlet temperature is unavoidable. [0009] Under these circumstances, when the raw material is fed as the quench fluid as in Patent Document 1, since the amount of the raw material increases, the equilibrium inclines toward the reaction product side. For that reason, since the reaction rate sensitively varies with the temperature change at the inlet of the catalyst bed, the influence of the temperature at the inlet of the catalyst bed against the temperature at 4 the outlet of the reactor becomes large. As a result, the deviation of the temperature at the outlet of the reactor becomes large, and the change of conversion also becomes large. For that reason, the temperature at the outlet of the reactor becomes excessively high, and a by-product is formed due to an undesirable side reaction, thereby lowering the purity of a product. Also, the temperature at the outlet of the reactor becomes excessively low so that a desired yield is not obtainable. For that reason, in a reactor having a simple configuration capable of realizing a large scale, a technology which enables one to control the temperature within the reactor by a simple and easy method is required. [0010] Patent Document 1: JP-A-2004-298768 (paragraphs 0014, 0020 and 0021) Disclosure of the Invention [0011] Under these circumstances, the invention has been made and is aimed to provide a technology for feeding a raw material into an adiabatic reactor and manufacturing an objective product by an equilibrium exothermic reaction within this reactor, wherein controllability of the reaction rate within the reactor is enhanced, thereby suppressing the formation of a by-product to be caused due to a temperature rise or the reduction of the yield to be caused by a lowering of the temperature. [0012] The reaction rate controlling method of the inside of the reactor according to the invention is concerned with a reaction rate controlling method including dividing a reaction region in the plural number, allocating the divided plural reaction regions into one or two or more adiabatic - 5 reactors, feeding a raw material into the adiabatic reactor and manufacturing an objective product by an equilibrium exothermic reaction, which comprises the steps of: feeding the raw material into a first-stage reaction region to obtain an reaction product containing objective product; subsequently successively feeding a mixture composed of the reaction product taken out from the reaction region on the preceding side and an unreacted raw material into the latter reaction region to obtain an object-containing reaction product; and feeding a quench fluid into the mixture in at least one region between the reaction regions and mixing them to incline the equilibrium of the mixture toward the raw material side, the quench fluid containing at least one of a part of the reaction product obtained in the latter reaction region than the feed region of the quench fluid and the same compound as the objective product obtained from another adiabatic reactor. [0013] The quench fluid may contain a part of the reaction product after cooling the reaction product obtained in a final-stage reaction region. It is preferable that the plural reaction regions are each configured of a catalyst bed. It is preferable that the number of the divided reaction regions is three. It is preferable that the process of inclining the equilibrium of the mixture toward the raw material side, is carried out by adjusting at least one of the feed amount, composition and temperature of the quench fluid. [0014] The equilibrium exothermic reaction may be a reaction of using methanol as the raw material to obtain a reaction - 6 217O0 3 tMHhntinr PAW All product composed of water and dimethyl ether which is the objective product. In that case, it is preferable that the quench fluid contains either dimethyl ether or a mixed fluid of dimethyl ether and water. (0015] A reaction apparatus according to the invention is concerned with a reaction apparatus for manufacturing an objective product by an equilibrium exothermic reaction by feeding a raw material into an adiabatic reactor, which comprises: one or two or more adiabatic reactors formed by dividing a reaction region into the plural number and allocating the divided plural reaction regions; a unit for feeding a raw material into a first-stage reaction region; a quench zone to be located in at least one place between the reaction regions, which acts to incline the equilibrium of the mixture toward the raw material side, a mixture composed of the reaction product and an unreacted raw material which are taken out from the reaction region on the preceding side by feeding a quench fluid to the mixture and mixing them and mix them; and a unit for feeding to incline the equilibrium of the mixture in the latter reaction region than the quench zone toward the raw material side, as the quench fluid, a fluid into the quench zone which contains at least one of a part of the reaction product obtained in the reaction region on the latter side of the quench zone and a compound the same as the objective product obtained outside the adiabatic reactor. [0016] It is preferable: that the reaction apparatus is provided with a cooling unit for cooling the reaction product obtained ina final-stage reaction region; and -7that the quench fluid is a fluid containing a part of the reaction product after cooling by the cooling unit. It is preferable that the plural reaction regions are each configured of a catalyst bed. It is preferable that the number of the divided reaction regions is three. Also, it is preferable that the reaction apparatus according to the invention is provided with a control section for adjusting at least one of the feed amount, composition and temperature of the quench fluid and feeding the quench fluid into the quench zone. [00171 The equilibrium exothermic reaction may be a reaction of using methanol as the raw material to obtain a reaction product composed of water and dimethyl ether which is the objective product. In that case, it is preferable that the quench fluid contains either dimethyl ether or a mixed fluid of dimethyl ether and water. [0018] A method for manufacturing dimethyl ether according to the invention is concerned with a method including dividing a reaction region in the plural number, allocating the divided plural reaction regions into one or two or more adiabatic reactors, feeding methanol into the adiabatic reactor and manufacturing dimethyl ether by a dehydration condensation reaction that is an equilibrium exothermic reaction, which comprises the steps of: feeding methanol into a first-stage reaction region to obtain a reaction product composed of dimethyl ether and water; subsequently successively feeding a mixture composed of the reaction product and unreacted methanol which are taken out from the reaction region on the preceding side into the reaction region on the latter side to obtain a reaction product composed of dimethyl ether and water; and - 8feeding a quench fluid into the mixture in at least one place between the reaction regions and mixing them to incline the equilibrium of the mixture toward the methanol side, the quench fluid containing at least one of dimethyl ether and water obtained in the reaction region on the latter side of the feed region of the quench fluid, and dimethyl ether obtained outside the adiabatic reactor. [0019] It is preferable that the process of inclining the equilibrium of the mixture toward the methanol side is carried out by adjusting at least one of the feed amount, composition and temperature of the quench fluid. It is preferable that the quench fluid contains either dimethyl ether or water after cooling as obtained in a final-stage reaction region. It is preferable that the plural reaction regions are each configured of a catalyst bed. It is preferable that the number of the divided reaction regions is three. It is preferable that the quench fluid is a part of dimethyl ether after removing water which is a by-product and unreacted methanol intermingled in dimethyl ether. [0020] According to the invention, in dividing a reaction region in the plural number, allocating the divided plural reaction regions into one or two or more adiabatic reactors, feeding a raw material into the adiabatic reactor and manufacturing an objective product by an equilibrium exothermic reaction, a mixture composed of an object-containing reaction product obtained by feeding the raw material into a first-stage reaction region and an unreacted raw material is successively fed from this first-stage reaction region into the reaction region on the latter side to obtain an object-containing reaction product; and at least one of a part of the reaction - 9 product obtained in the reaction region on the latter side of the feed region of the quench fluid and a compound the same as the objective product obtained outside the adiabatic reactor is fed as a quench fluid in at least one place between the reaction regions. For that reason, the amount of the reaction product in the mixture increases, the equilibrium inclines toward the raw material side, and the reaction gently proceeds. Therefore, the change in reaction rate to be caused due to the temperature change on the inlet side of the reaction region is small. As a result, controllability of the temperature within the reactor is enhanced, and the unexpected formation of a by-product due to the temperature rise and a reduction of the yield due to a lowering of the temperature can be suppressed simply and easily. Brief Description of the Drawings Fig. 1 is a diagrammatic configurative view showing one embodiment of a reaction apparatus for carrying out a manufacturing method of the invention. Fig. 2 is a diagrammatic view showing one embodiment of a temperature change of a raw material within a reactor in the foregoing reaction apparatus. Fig. 3 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 4 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 5 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 6 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 7 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 8 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. - 10 - Fig. 9 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 10 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 11 is a longitudinal cross-sectional view showing other embodiment of the foregoing reaction apparatus. Fig. 12 is a diagrammatic view showing an apparatus used in the Comparative Example in the Examples of the invention. Fig. 13 is a diagrammatic view showing an apparatus used in the Comparative Example in the Examples of the invention. Fig. 14 is a diagrammatic view showing a conventional apparatus to be used for a synthesis reaction. Fig. 15 is a diagrammatic view showing a conventional apparatus to be used for a synthesis reaction. Best Mode for Carrying Out the Invention [0021] Embodiments of a reaction apparatus and a reaction rate controlling method using this apparatus according to the invention are described with reference to Figs. 1 and 2. Fig. 1 shows an outline of the whole of a manufacturing plant including a reaction apparatus 2 for manufacturing an objective product. The reaction apparatus 2 is provided with, for example, a vertical reactor 20 which is an adiabatic fixed - 11 bed reactor. One end side of a raw material gas feed pipe 20a which is a unit for feeding a raw material is connected to a top of this reactor 20, and a raw material storage source 4 in which a liquid raw material is stored is connected to the other end side of this raw material gas feed pipe 20a via a heat exchanger 2a and an evaporator 2b. The evaporator 2b is one for obtaining a raw material gas by vaporizing the liquid raw material. [0022] One end side of a product gas discharge pipe 20b is connected to a bottom of the reactor 20, and the heat exchanger 2a is connected to this product gas discharge pipe 20b. This heat exchanger 2a is configured such that heat exchange is carried out between the raw material within the raw material gas feed pipe 20a and a mixture composed of a reaction product and the raw material within the product gas discharge pipe 20b by heating the raw material and cooling the mixture, respectively. The other end side of this product gas discharge pipe 20b is connected to a side wall of a first distillation column 30 as described later. (0023] In the inside of the reactor 20, a reaction region necessary for obtaining a desired reaction yield, for example, a catalyst bed 22, is provided dividedly on the upstream side and downstream side; the reaction region on the upstream side is formed as a first reaction region by a first catalyst bed 22a; and the reaction region on the downstream side is formed as a second reaction region by a second catalyst bed 22b. These catalyst beds 22 (22a, 22b) are supported by supports 23 on which a number of non-illustrated gas feed holes are formed. [0024] A quench zone Q for cooling the mixture within the reactor 12 20 by a quench fluid is provided in a region between the first catalyst bed 22a and the second catalyst bed 22b within the reactor 20. A quench fluid feed pipe 24 which is a unit for feeding a part of the reaction product as the quench fluid into the quench zone is connected to a side surface of the reactor 20 in this quench zone Q. This quench fluid feed pipe 24 is connected to a spray section 24a on which plural discharge holes 24b for uniformly dispersing and feeding a quench fluid are formed in a site near the first catalyst bed 22a on the upper side of the quench zone Q within the reactor 20. [0025] Also, a temperature detection section 29 is provided on the side surface of the reactor 20 and configured such that one end side thereof is projected within the reactor 20 to detect a temperature of the mixture cooled in the quench zone Q, for example, in the vicinity of the upper side of the second catalyst bed 22b. A control section 3 is connected to this temperature detection section 29 and configured so as to control a flow rate of the quench fluid by a flow rate adjusting valve 27 as described later on the basis of the detection temperature of the temperature detection part 29 such that the temperature of the raw material gas maintains within the temperature range suitable for the reaction. Equipment for taking out the desired reaction product from the mixture obtained from the reactor 20 and feeding a part thereof as a quench fluid into the reactor 20 is provided in the latter part of the reactor 20. In Fig. 1, for example, equipment including two distillation columns 30 and 40 for obtaining dimethyl ether as the objective product is provided. [0026] The first distillation column 30 is one for separating and purifying the objective product from the mixture composed 13 of an unreacted raw material and a reaction product, in which an objective product takeout pipe 31 which is a cooling unit is connected to a column top thereof, and one end side of a discharge pipe 32 is connected to the lower end thereof. The first distillation column 30 is configured such that though the objective product discharged from the objective product takeout pipe 31 is taken out as a product from the system, a part thereof is returned as a quench fluid to the previously described quench zone Q by the previously described quench fluid feed pipe 24 branched from this objective product takeout pipe 31. The flow control valve 27 is inserted on the quench fluid feed pipe 24. [0027] The other end side of the previously described discharge pipe 32 is connected to a side wall of the second distillation column 40. This second distillation column 40 is one for separating and purifying the unreacted raw material from the mixture from which the objective product has been removed in the first distillation column 30, in which one end side of a raw material discharge pipe 41 is connected to a top thereof, and a discharge pipe 42 is connected to a bottom thereof. The other end side of the raw material discharge pipe 41 is connected to the raw material gas feed pipe 20a on the upstream side of the previously described evaporator 2b and configured so as to return the unreacted raw material and reuse it. The discharge pipe 42 is one for disposing of a by-product or impurities remaining after removing the objective product and the unreacted raw material from the mixture, and these are discharged from the system. [0028] Subsequently, a method for operating the reaction apparatus 2 is described with reference to Figs. 1 and 2. 14 A liquid raw material constituted of a single substance or plural substances is vaporized by the evaporator 2b provided in the preceding and heat exchanged with the mixture composed of the unreacted raw material and the reaction product taken out from the reactor 20 in the heat exchanger 2a, whereby it is heated to a temperature Tl. Thereafter, the raw material gas is fed into the reactor 20 via the raw material gas feed pipe 20a and flows in the upper to lower direction within this reactor 20. Then, the object-containing reaction product is formed within the first catalyst bed 22a according to an equilibrium reaction represented by the following equation (1), whereby a gas of a mixture containing this reaction product and the unreacted raw material gas is formed. (Raw material gas) <> (Reaction product (objective product (+ by-product)) + (Reaction heat) (1) [0029] The temperature of the gas of the mixture is raised by the reaction heat generated at that time and reaches a temperature T2. In the case of manufacturing dimethyl ether, methanol which is a liquid raw material is vaporized, whereby dimethyl ether and water are produced within the first catalyst bed 22a according to an equilibrium reaction represented by the following equation (2). 2CH 3 0H <> CH 3 0CH 3 + H 2 0 + AH (2) AH = -23.4 kJ/mol [0030] Subsequently, in the quench zone Q, the quench fluid is fed from the spray section 24a and this quench fluid is mixed with the gas of the mixture of which the temperature has become high (T2) due to the exothermic reaction in the preceding catalyst 15 bed 22a, whereby the temperature of the mixture reaches T3. This quench fluid is a fluid composed of a part of the reaction product obtained in the subject reaction apparatus 2 and is fed in a liquid phase or gas phase. In the case of manufacturing dimethyl ether, for example, dimethyl ether which is a gas is used as the quench fluid. By feeding a part of the reaction product as the quench fluid in such a way, the amount of the reaction product on the right side of the foregoing equation (1) or (2) is increased within the second catalyst bed 22b, and therefore, the equilibrium reaction of the equation (1) or (2) inclines toward the raw material side, and the reaction for forming the objective product is suppressed. Thus, the foregoing reaction gently proceeds. [0031] The thus cooled gas of the mixture, in more detail, the quench fluid-containing mixture, is fed into the second catalyst bed 22b, and a reaction product is gently produced in the second catalyst bed 22b by the same reaction. The temperature of the mixture composed of this reaction product and the unreacted raw material is raised to T4 by the reaction heat generated due to the reaction in this second catalyst bed 22b. Thereafter, the mixture is taken out from the reactor 20 via the product gas discharge pipe 20b and heat exchanged with the raw material in the heat exchanger 2a. [0032] Then, the sequential flow is described by taking the case of manufacturing dimethyl ether as an example. The mixture discharged from the reactor 20, which is composed of dimethyl ether as a reaction product, water and methanol as the unreacted raw material, is fed into the first distillation column 30, 16 whereby dimethyl ether which is the objective product is purified. Dimethyl ether purified from the mixture is taken out from the objective product takeout pipe 31 and radiates heat against a pipe wall of the objective product takeout pipe 31 and the like to reach a temperature not higher than the previously described temperature T2, a part of which is then returned as the quench fluid to the reactor 20 via the quench fluid feed pipe 24. The residual dimethyl ether is taken out as a product from the system. [0033] The mixture from which dimethyl ether has been removed is discharged from the bottom of the first distillation column 30 and fed into the second distillation column 40, and methanol which is the unreacted raw material is purified in this second distillation column 40. As described previously, the unreacted raw material is returned to the raw material gas feed pipe 20a and again fed into the reactor 20 together with the raw material to be fed from the raw material storage source 4. Also, a waste which is the by-product, from which the objective product and the unreacted raw material have been removed, water in this embodiment, is discharged from the system. [0034] Here, the temperature T3 at the inlet of the catalyst bed 22b is detected by the temperature detection section 29; and the feed flow rate of the quench fluid is controlled via the control section 3 and the flow control valve 27 depending upon its temperature detection value, whereby it is devised to stabilize the inlet temperature T3 of the catalyst bed 22b. But, it is unavoidable that the inlet temperature T3 fluctuates within a certain range. However, in the invention, since the reaction product is used as the quench fluid, as described 17 previously, the equilibrium reaction inclines toward the raw material side, and the reaction for forming the objective product is suppressed. Therefore, the influence of the inlet temperature Tl of the catalyst bed 22a against the outlet temperature T4 of the catalyst bed 22b is small. That is, since the change in reaction rate to the objective product is small against the change in the inlet temperature Tl of the catalyst bed 22a, the change in the outlet temperature T4 of the catalyst bed 22b becomes insensitive, and a range of deviation of the conversion is small. [00351 According to the foregoing embodiment, in feeding the raw material into the adiabatic reactor 20 to manufacture the objective product by an equilibrium exothermic reaction , the quench zone Q is provided between the first reaction region and the second region for carrying out the reaction of the raw material; and a part of the reaction product taken out from the second reaction region is cooled and fed as the quench fluid into this quench zone Q, thereby cooling the mixture composed of the raw material and the reaction product. For that reason, as described previously in detail, the amount of the reaction product in the mixture increases, the equilibrium inclines toward the raw material side, and the reaction gently proceeds. Therefore, the temperature control within the reactor 20 becomes easy. As a result, not only the unexpected formation of a by-product to be caused due to the temperature rise can be suppressed, but a reduction of the yield to be caused due to a lowering of the temperature can be suppressed. Furthermore, the catalyst life can be increased while suppressing coking of the catalyst. Moreover, an abrupt temperature rise (runaway reaction) in the reaction apparatus 2 can be suppressed, and the reaction apparatus 2 can be stably 18 operated. In consequence, as compared with existing methods, the configuration of the reactor 20 can be simplified and is easy to realize a large scale, and the number of components which configure the reactor 20 can be decreased. [0036] The quench fluid may be a gas or may be a liquid. In the case of using a gaseous quench fluid, since latent heat of vaporization cannot be utilized, it is necessary to increase the feed amount as compared with the case of using the liquid. However, since the amount of the reaction product within the reactor 20 is large, an effect for suppressing the reaction rate is large. On the other hand, in the case of using a liquid quench fluid, the temperature of the mixture can be lowered in a feed amount smaller than that in the case of using the gas. For example, in the case where the feed amount of the raw material is small, and the temperature rise of the mixture due to the reaction is small, the liquid quench fluid may be fed as the quench fluid without cooling the reaction product. In such case, since the amount of the reaction product within the reactor 20 is large, the reaction rate is suppressed. [0037] In the foregoing embodiment, while the catalyst bed 22 is configured of two layers, for example, the catalyst bed may be configured of more than two beds as shown in Figs. 3 and 4. Fig. 3 shows a reactor 20 provided with three catalyst beds (22a, 22b, 22c); and Fig. 4 shows a reactor 20 provided with five catalyst beds (22a, 22b, 22c, 22d, 22e). In Figs. 3 and 4, the temperature of the mixture is detected by the temperature detection section 29 in the quench zone Q between the respective catalyst beds 22, whereby the flow rate of the quench fluid to be fed from the spray section 24a is adjusted. In such a reactor 20, the reaction also proceeds in a state that the 19 reaction rate is suppressed by the quench fluid in the same way as in the foregoing embodiment. In this way, by configuring the catalyst bed 22 of plural beds, the same effects as in the foregoing embodiment are obtained. [0038] Also, besides the case of providing the catalyst bed 22 configured of plural beds within the single reactor 20, for example, plural reactors 20 provided with a single catalyst bed 22 may be connected to each other as shown in Figs. 5 and 6. Figs. 5 and 6 show an embodiment in which three of such reactors 20 are connected to each other and an embodiment in which five of such reactors 20 are connected to each other, respectively. A quench fluid feed pipe 24 is connected to a product gas discharge pipe 20b which connects the respective reactors 20 to each other. Furthermore, in addition to such reactors 20, for example, plural reactors 20 provided with at least one catalyst bed 22 may be combined and connected as shown in Figs. 7 and 8. Fig. 7 shows an embodiment in which a reactor 20 provided with a single catalyst bed 22 and a reactor 20 provided with two catalyst beds (22a, 22b) are connected to each other in series. Fig. 8 shows an embodiment in which a reactor 20 provided with two catalyst beds (22a, 22b) and a reactor 20 provided with three catalyst beds (22a, 22b, 22c) are connected to each other in series. The configuration is made in such a manner that a quench fluid is similarly fed into a quench zone Q between these catalyst beds 22. Even in such configurations, the same effects as in the foregoing embodiments are obtained. [0039] In each of the foregoing embodiments, it is preferable that the quench zone Q is provided all between the respective catalyst beds 22, 22. However, for example, in the case where 20 a range of deviation of the temperature is small, the number of quench zones Q may be decreased, namely it is sufficient that at least one quench zone Q is provided. Fig. 9 shows an embodiment in which in the reactor 20 as shown in the previously described Fig. 4, the quench zone Q between the second catalyst bed 22b and the third catalyst bed 22c from the upstream side is omitted. Even in such a reactor 20, the same effects are obtained. [0040] Also, in the foregoing embodiments, while the objective product within the system is utilized as the quench fluid, a compound the same as the objective product outside the system can also be utilized as the quench fluid. As such an embodiment, for example, as shown in Fig. 10, plural reaction apparatuses 2 may be provided in such a manner that the quench fluid is fed from the reaction apparatus 2 on one side into the other reaction apparatus 2. In such case, an objective product takeout pipe 31 of the reaction apparatus 2 on one side is connected with a quench fluid feed pipe 24 of the other reaction apparatus 2. In the foregoing Figs. 3 to 10, the same configurations as in Fig. 1 are given the same symbols. The objective product which is the quench fluid maybe intermingled with the unreacted raw material. [0041] Furthermore, besides the matter that the objective product is utilized as the quench fluid, for example, in the case where a reaction product (by-product) other than the objective product is formed from the raw material (the case where a substance to be formed in the right side of the equation (1) is also present other than the objective product), the subject reaction product may be utilized as the quench fluid. For example, in the reaction for obtaining dimethyl ether, 21 water may be used as the quench fluid. In that case, as shown in Fig. 11, the whole amount of the objective product is taken out from the objective product takeout pipe 31, and a part of the waste is returned as the quench fluid to the quench zone Q. Even in this case, since the reaction is suppressed due to the matter that the amount of the reaction product on the right side of the foregoing equation (1) or (2) is increased similar to the foregoing embodiments, the reaction gently proceeds, and a range of deviation of the temperature of the mixture at the outlet of the reactor 20 becomes small. Also, in Fig. 11, the same configurations as in the previously described Fig. 1 are given the same symbols. The objective product may be used as the quench fluid together with this by-product, and for example, in the reaction for obtaining dimethyl ether from methanol, dimethyl ether and water may be used as the quench fluid. Furthermore, dimethyl ether from the outside of the system may be utilized as the quench fluid. [0042] Also, in the each of the foregoing embodiments, while the reaction product or a compound outside the system which is the same as the objective product is used as the quench fluid, the unreacted raw material may be contained in this quench fluid so far as the reaction product or a compound outside the system which is the same as the objective product is contained to such an extent that the reaction rate is suppressed. In that case, for example, in Fig. 1, the unreacted raw material may be positively used as a part of the quench fluid by connecting one end side of a branch pipe on which is inserted a valve (all of which are not illustrated) to a raw material discharge pipe 41, connecting the other end side of this branch pipe to a quench fluid feed pipe 24 and adjusting a degree of opening of this 22 [0043] Furthermore, in each of the foregoing embodiments, the flow rate of the quench fluid is controlled by the control section 3, thereby stabilizing the inlet temperature T3 of the reactor 20. However, the inlet temperature T3 may also be stabilized by making the flow rate of the quench fluid constant and adjusting, for example, the degree of opening of each of the foregoing valve of the branch pipe and the flow control valve 27 via the control section 3, thereby adjusting a proportion of the reaction product or the compound outside the system which is the same as the objective product, each of which is contained in the quench fluid, namely a composition of the quench fluid. Also, the inlet temperature T3 of the reactor 20 may be stabilized by providing a non-illustrated cooling mechanism in the quench fluid feed pipe 24 to make the flow rate the quench fluid constant and controlling the temperature of this quench fluid via the control section 3. Moreover, the inlet temperature T3 of the reactor 20 may be stabilized by combining and controlling the plurality of the flow rate of the quench fluid, the composition of the quench fluid and the temperature of the quench fluid via the control section 3. [0044] As described previously, in the case of forming an objective product by an equilibrium exothermic reaction, the reaction rate controlling method of an objective product and the reaction apparatus according to the invention may be applied to, for example, a synthesis reaction of dimethyl ether by dehydration of methanol in the Examples as described later or a synthesis reaction from ammonia from hydrogen and nitrogen, or the like. Also, in addition to the foregoing synthesis reactions, the reaction rate controlling method of an objective - 23 product and the reaction apparatus according to the invention may be applied to an equilibrium exothermic reaction, for example, an oxidation reaction, a hydrogenation reaction and other reactions and may also be applied to these reactions in a liquid phase. Examples [0045] Experiments which were carried out for the purpose of confirming the effects of the method according to the invention are hereunder described. In these Examples, experiments for obtaining dimethyl ether as the objective product by an equilibrium exothermic reaction in the previously described equation (2) using methanol as the foregoing raw material. Also, in each of the following experiments, a standard condition is set up. This standard condition is a condition set up so as to make the conversion of methanol at the outlet of the final catalyst bed and the temperature at the outlet of each of the catalyst beds equal under each of the standard conditions. [0046] (Example 1) The reaction apparatus 2 as shown in the previously described in Fig. 1 was used as an apparatus for carrying out the foregoing reaction, and a thermometer was provided at an inlet of the reactor 20 and an inlet and an outlet of each of the catalyst beds 22a, 22b, respectively. In this reaction apparatus 2, methanol was fed at a flow rate of Fl; dimethyl ether was fed as a quench fluid at a flow rate of F2 into the quench zone Q; and unreacted methanol was returned at a flow rate of F3. Water which is a by-product was discharged from the previously described discharge pipe 24 42. The respective flow rates Fl to F3 express a mass flow rate of each of the fluids. [0047] As to the experimental condition, each of the following conditions was determined such that the conversion of methanol and the temperature at the outlet of the reactor 20 were 75 % and 340 *C, respectively, and this condition was defined as the standard condition. Also, an experiment was carried out under the same condition as the foregoing standard condition, except for changing the temperature of the raw material at the inlet of the reactor 20 by every 1 *C up and down from the standard condition. The temperature at the outlet of the reactor 20 (temperature on the outlet side of the second catalyst bed 22b) and the conversion of methanol at the outlet of the reactor 20 were compared under each of the conditions. As to the flow rates F2 of dimethyl ether as the quench fluid arid the flow rate F3 of methanol as the unreacted raw material to be returned from the raw material discharge 41, the same flow rates under the standard condition were employed. [0048] (Standard condition) Temperature at the inlet of reactor 20: 279 *C Pressure at the inlet of reactor 20: 1.55 MPa (gauge pressure) Ratio of quench amount to flow rate of raw material (F2/(Fl + F3)): 0.18 Quench dimethyl ether condition: 1.5 MPa (gauge pressure) at dimethyl ether saturated vapor (100 %) [0049] (Experimental results) The experimental results are shown in Table 1. Table 1 25 0 Change in inlet temperature of (Standard first catalyst bed from the -1 +1 standard operation condition (*C) condition) Conversion (%) 73 75 77 Inlet 278 279 280 First catalyst temperature (*C) bed Outlet 334 338 342 temperature (*C) Inlet 296 299 303 Second temperature (*C) catalyst bed Outlet 336 340 342 temperature (*C) Change in outlet temperature of second catalyst bed from the -4 0 +2 standard operation condition (*C) [0050] As a result, the temperature within the reactor 20 changed with the change in temperature at the inlet of the reactor 20 (temperature on the inlet side of the first catalyst bed 22a) . Also, it was understood that the change in temperature at the outlet of the reactor 20 was larger than the change in temperature at the inlet of the reactor 20. When the temperature within the reactor 20 was high, the conversion increased, whereas when the temperature within the reactor 20 was low, the conversion decreased. [0051] (Comparative Example 1-1) Subsequently, as Comparative Example 1-1, the distillation columns 30 and 40 were connected to the apparatus in which the heat exchanger 103 was inserted between the plural 26 reactors 102, 102 as shown in the previously described Fig. 15, and an experiment was carried out. This apparatus is shown in Fig. 12. Sites having the same configurations as in the previously described Fig. 1 are given the same symbols. In this apparatus, the temperature of the raw material at the inlet and the outlet of each of the reactor 102 on the upstream side (first reactor) and the reactor 102 on the downstream side (second reactor) was also measured. This apparatus was configured such that the raw material gas after vaporization in the evaporator 2b was fed into the heat exchanger 103 via a feed pipe 200 and that heat exchanged between this raw material gas and a mixture composed of the raw material and a reaction product which had reached a high temperature by the reaction in the reactor 102 on the upstream side in this heat exchanger 103 (so as to cool the mixture). The raw material gas after heat exchange (heating) in this heat exchanger 103 was returned to the raw material gas feed pipe 20a on the side before the reactor 102 on the upstream side. The flows of the raw material and the reaction product and the like other than the fluid to be fed into this heat exchanger 103 were the same as in the reaction apparatus 2 as shown in the previously described in Fig. 1. [0052] Then, similar to the foregoing Example 1, each of the following conditions was determined such that the conversion of methanol and the temperature of the raw material at the outlet of the reactor 102 on the downstream side were 75 % and 340 *C, respectively, and this condition was defined as the standard condition. Also, an experiment was carried out under the same condition as the standard condition, except for changing the temperature of the raw material at the inlet of the reactor 102 by every 1 *C up and down from the standard 27 condition. [0053] Then, the temperature at the outlet of the reactor 102 on the downstream side was similarly measured, and the conversion was also compared. As to the amount of methanol to be returned from the raw material discharge pipe 41, the same flow rate under the standard condition was employed. Also, it was supposed that even when the temperature at the inlet of the reactor 102 on the upstream side changes, the amount of heat exchange (amount of heat transfer) between the quench fluid and the mixture in the heat exchanger 103 does not change. [0054] (Standard condition) Temperature at the inlet of reactor 102: 279 *C Pressure at the inlet of reactor 20: 1.55 MPa (gauge pressure) [0055] (Experimental results) The experimental results are shown in Table 2. Table 2 28 0 Change in inlet temperature of (Standard first reactor from the standard -1 +1 operation condition (*C) operation condition) Conversion (%) 71 75 78 Inlet 278 279 280 First reactor temperature (*C) Outlet 334 338 342 temperature (*C) Inlet 287 291 296 temperature ( 0 C) ___ Second reactor Outlet 333 340 345 temperature (*C) Change in outlet temperature of second reactor from the standard -7 0 +5 operation condition (*C) [0056] As a result, similar to Example 1, the temperature and conversion in each section changed with the change in temperature on the upstream side. However, change amounts thereof were larger than those in Example 1. It is understood from this matter that in Example 1, by using, as the quench fluid, dimethyl ether which is the reaction product, the reaction is suppressed, whereby the controllability of temperature of the inside of the reactor 20 and conversion is enhanced. [0057] (Comparative Example 1-2) Next, an experiment was carried out using an apparatus as shown in Fig. 13 as the apparatus having the same configuration as the apparatus described in the previously 29 described Patent Document 1. Though this apparatus is diagrammatically provided with a reactor 300 having substantially the same configuration as in the reactor 20 as shown in Fig. 1, it is configured such that the liquid raw material is fed as the quench fluid from a raw material quench feed pipe 200. In this Fig, 13, sites having the same configurations as in Fig. 1 are given the same symbols, too. [00581 Then, similar to the foregoing experiments, each of the following conditions was determined such that the conversion of methanol and the temperature of the raw material on the outlet side of the reactor 300 were 75 % and 340 *C, respectively, and this condition was defined as the standard condition. An experiment was similarly carried out while changing the temperature on the inlet side of the reactor 300 by every 1 *C up and down. In this case, the flow rate of unreacted methanol to be returned from the raw material discharge pipe 41 and the flow rate of the quench fluid were made constant, too. In this example, Fl expresses a feed amount of methanol; F2 expresses a feed amount of quench methanol; and F3 expresses a flow rate of methanol to be recycled, too. [0059] (Standard condition) Temperature at the inlet of reactor 300: 279 *C Pressure at the inlet of reactor 300: 1.55 MPa (gauge pressure) Ratio of quench amount to flow rate of raw material (F2/(F1 + F3)): 0.09 Quench methanol condition: 1.6 MPa (gauge pressure), a liquid at boiling point [0060] (Experimental results) 30 The experimental results are shown in Table 3. Table 3 0 Change in inlet temperature of (Standard first catalyst bed from the -1 +1 standard operation condition (*C) operation condition) Conversion (%) 71 75 78 Inlet 278 279 280 First catalyst temperature (*C) bed Outlet 336 341 345 temperature (*C) Inlet 286 290 294 Second temperature ("C) catalyst bed Outlet 334 340 345 temperature ("C) Change in outlet temperature of second catalyst bed from the -6 0 +5 standard operation condition (*C) [0061] In these results, the temperature and conversion in each section in the inside of the reactor 300 changed by the temperature at the inlet of the reactor 300, too. However, similar to Comparative Example 1-1, change amounts thereof were larger than those in Example 1. [0062] It was understood from the foregoing results that in the case of using the raw material as the quench fluid, since the equilibrium reaction inclines toward the reaction product side, and the reaction rate to the desired product becomes high, the quantity of generation of heat becomes large, and as a result, fluctuation in temperature of the mixture at the outlet of the 31 reactor 20 becomes large; whereas by using a part of the reaction product as the quench fluid, the reaction to the desired product is suppressed, whereby a range of deviation of the temperature of the mixture at the outlet of the reactor 20 can be made small. [0063] (Example 2) Next, in the case where the catalyst bed 22 is configured of three beds as shown in the previously described Fig. 3, for the purpose of confirming how the temperature and the conversion at the outlet of the reactor 20 change, an experiment was carried out. In the experiment, by using the reactor 20 as shown in Fig. 3, each of the following conditions was determined such that the conversion of methanol and temperature at the outlet of the reactor 20 were 75 % and 340 *C, respectively, and this condition was defined as the standard condition. Also, an experiment was carried out under the same condition as the standard condition, except for similarly changing the temperature of the raw material at the inlet of the reactor 20 by every 1 *C up and down. Then, the temperature at the inlet and the temperature at the outlet of each of the catalyst beds 22 of the reactor 20 were measured under each of the conditions, and the conversion of methanol at the outlet of the reactor 20 was compared. As to the flow rates of the flow rate F2 of dimethyl ether which is the quench fluid and the flow rate F3 of methanol which is the unreacted raw material to be returned from the raw material discharge 41, the same flow rates under the standard condition were employed. [0064] (Standard condition) Temperature at the inlet of reactor 20: 279 *C 32 Pressure at the inlet of reactor 20: 1.55 MPa (gauge pressure) Ratio of quench amount to flow rate of raw material (F2/(F1 + F3)): 0.18 Quench dimethyl ether condition: 1.5 MPa (gauge pressure) at dimethyl ether saturated vapor (100 %) [0065] (Experimental results) The experimental results are shown in Table 4. Table 4 0 Change in inlet temperature of (Standard first catalyst bed from the -1 +1 standard operation condition (*C) operation condition) Conversion (%) 73 75 77 Inlet 278 279 280 First catalyst temperature (*C) bed Outlet 302 304 306 temperature (*C) 302 _304_306 Inlet 284 286 288 Second temperature (*C) catalyst bed Outlet 320 324 329 temperature ("C) Inlet 302 306 311 Third catalyst temperature (*C) bed Outlet 337 340 343 temperature (*C) Change in outlet temperature of third catalyst bed from the -3 0 +3 standard operation condition (*C) [0066] 33 As a result, it was understood that by using the product as the quench fluid, similar to the results of Example 1, even when the temperature on the inlet side of the reactor 20 changes, the change in temperature on the outlet side of the reactor 20 and conversion can be suppressed. [0067] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. [0068] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. [0069] It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. - 34 -

Claims

1. A reaction rate controlling method of the inside of a reactor including dividing a reaction region into the plural number, allocating the divided plural reaction regions into one or two or more adiabatic reactors and feeding a raw material into the adiabatic reactor or reactors to manufacture an objective product by an exothermic equilibrium reaction, which comprises the steps of: feeding the raw material into a first-stage reaction region to obtain reaction products containing an objective product; subsequently successively feeding a mixture composed of the reaction products and an unreacted raw material taken out from the reaction region on the preceding side into the latter reaction region to obtain reaction products containing an objective product; and feeding a quench fluid into the mixture in at least one region between the reaction regions and mixing them to incline the equilibrium of the mixture toward the raw material side, the quench fluid containing at least one of a part of the reaction products obtained in the latter reaction region than the feed region of the quench fluid and the same compound as the objective product obtained outside the adiabatic reactor.

2. The reaction rate controlling method of the inside of - 35 - the reactor according to claim 1, wherein the quench fluid contains a part of the reaction products after cooling the reaction products obtained in a final-stage reaction region.

3. The reaction rate controlling method of the inside of the reactor according to claim 1, wherein the plural reaction regions are each configured of a catalyst bed.

4. The reaction rate controlling method of the inside of the reactor according to claim 1, wherein the number of the divided reaction regions is three.

5. The reaction rate controlling method of the inside of the reactor according to claim 1, wherein the process of inclining the equilibrium of the mixture toward the raw material side is carried out by adjusting at least one of the flow rate, composition and temperature of the quench fluid.

6. The reaction rate controlling method of the inside of the reactor according to claim 1, wherein the exothermic equilibrium reaction is a reaction of using methanol as the raw material to obtain reaction products composed of water and dimethyl ether.

7. The reaction rate controlling method of the inside of the reactor according to claim 1, wherein the quench fluid contains either dimethyl ether or a mixed fluid of dimethyl ether and water.

8. A reaction apparatus for feeding a raw material into an adiabatic reactor to manufacture an objective product by an - 36 - exothermic equilibrium reaction, which comprises: one or two or more adiabatic reactors equipped with a divided reaction region into the plural number and allocating the divided plural reaction regions; a means for feeding a raw material into a first-stage reaction region; a quench zone located in at least one region between the reaction regions, which a quench fluid is fed to a mixture composed of the reaction products and an unreacted raw material taken out from the preceding reaction region and is mixed to the mixture to incline the equilibrium of the mixture toward the raw material side; and a means for feeding to incline the equilibrium of the mixture in the latter reaction region than the quench zone toward the raw material side, as the quench fluid, a fluid containing at least one of a part of the reaction products obtained in the latter reaction region than the quench zone and the same compound as the objective product obtained outside the adiabatic reactor into the quench zone.

9. The reaction apparatus according to claim 8, which is provided with a means for cooling the reaction products obtained in a final-stage reaction region; and wherein the quench fluid is a fluid containing a part of the reaction products after cooling by the cooling means.

10. The reaction apparatus according to claim 8, wherein the - 37 - plural reaction regions are each configured of a catalyst bed.

11. The reaction apparatus according to claim 8, wherein the number of the divided reaction regions is three.

12. The reaction apparatus according to claim 8, which is provided with a control section for adjusting at least one of the flow rate, composition and temperature of the quench fluid and feeding the quench fluid into the quench zone.

13. The reaction apparatus according to claim 8, wherein the exothermic equilibrium reaction is a reaction of using methanol as the raw material to obtain reaction products composed of water and dimethyl ether.

14. The reaction apparatus according to claim 8, wherein the quench fluid contains either dimethyl ether or a mixed fluid of dimethyl ether and water.

15. A method for manufacturing dimethyl ether including dividing a reaction region into the plural number, allocating the divided plural reaction regions into one or two or more adiabatic reactors and feeding methanol into the adiabatic reactor or reactors to manufacture dimethyl ether by a dehydration condensation reaction that is an equilibrium exothermic reaction, which comprises the steps of: feeding methanol into a first-stage reaction region to obtain reaction products composed of dimethyl ether and water; subsequently successively feeding a mixture composed of the reaction products and unreacted methanol taken out from - 38 - the preceding reaction region into the latter reaction region to obtain reaction products composed of dimethyl ether and water; and feeding a quench fluid into the mixture in at least one region between the reaction regions and mixing them to incline the equilibrium of the mixture toward the methanol side, the quench fluid containing either at least one of dimethyl ether and water obtained in the latter reaction region than the feed region of the quench fluid or dimethyl ether obtained outside the adiabatic reactor.

16. The method for manufacturing dimethyl ether according to claim 15, wherein the process of inclining the equilibrium of the mixture toward the methanol side is carried out by adjusting at least one of the flow rate, composition and temperature of the quench fluid.

17. The method for manufacturing dimethyl ether according to claim 15, wherein the quench fluid contains either dimethyl ether or water after cooling as obtained in a final-stage reaction region.

18. The method for manufacturing dimethyl ether according to claim 15, wherein the plural reaction regions are each configured of a catalyst bed.

19. The method for manufacturing dimethyl ether according to claim 15, wherein the number of the divided reaction regions is three. - 39 -

20. The method for manufacturing dimethyl ether according to claim 15, wherein the quench fluid is a part of dimethyl ether after removing water which is a by-product and unreacted methanol intermingled in dimethyl ether. - 40 2312059 3 (GHMattersI PS4386AU