KR830002469B1 - Exothermic reaction method of gaseous raw material in contact with granular catalyst layer - Google Patents

Abstract

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Description

Exothermic reaction method of gaseous raw material in contact with granular catalyst layer

1 is a longitudinal sectional view of a known reaction vessel.

2 is a longitudinal sectional view of one embodiment of a reaction vessel according to the present invention.

3 is an enlarged view showing one example of the arrangement of the central and peripheral catalyst receivers in the reaction vessel shown in FIG.

4 is a cross-sectional view of an example of the peripheral catalyst receiver shown in FIG.

5 shows an example of the structure of the peripheral and central catalytic receivers,

6 is a cross-sectional view of one example of a central catalytic receiver.

7 is a longitudinal sectional view of a central catalytic receiver.

8 illustrates a specific embodiment where a startinggas preheating heat exchanger is arranged in the central space of the reaction vessel of the present invention.

The present invention relates to a process for improving the reaction of gaseous raw materials by contacting a catalyst and to an improved vertical cylindrical reaction vessel for carrying out this reaction.

The conversion reaction achieved by contacting the starting material of the gas with a particulate catalyst under appropriate pressure is currently active for the synthesis, methanation and other various purposes of synthetic methanol of ammonia. In many cases, this conversion reaction is an exothermic reaction carried out under a pressure above atmospheric pressure. Thus, the temperatures of the gases and catalysts are excessively elevated by the heat of reaction, resulting in lower catalyst performance due to chemical equilibrium and reduced concentrations of the desired product. Therefore, such excessive rise in temperature of the gas and catalyst should be avoided and there have been many designs for this purpose.

The most popular method for removing the heat of reaction is to utilize the heat of reaction to preheat the starting gas to be supplied to the catalyst bed. In particular, according to this method, a heat exchange is carried out between the low temperature gas introduced into the catalyst bed and the hot gas leaving or in the bed to raise the temperature of the gas introduced into the catalyst bed to the level necessary to initiate the reaction. . Typically, heat exchange is carried out under substantially the same pressure as the reaction pressure, and the catalyst and gas-gas heat exchangers are arranged in one reaction vessel.

In this method for preheating the gas introduced by utilizing the heat of reaction, the amount of heat of reaction is greater than the amount of heat required for preheating, and the temperature at the outlet side in the catalyst bed is considerably higher than the temperature at the inlet side. Thus, satisfactory advantages can be obtained with respect to the catalytic activity or chemical equilibrium described above. In addition, this method requires a separate device to fully recover the excess thermal reaction, and has a defect in that the level of recovered thermal energy is reduced.

Another method of reaction heat removal that is frequently employed is to remove the heat of reaction by evaporating the liquid under moderate pressure. As the evaporating liquid, Dowtherm or a hydrocarbon mixture having a suitable boiling point may be used, but water is most adopted from a practical point of view.

In this method, it is essential that the liquid is evaporated under pressure which provides a suitable boiling point below the catalyst temperature in order to prevent excessive rise of the catalyst temperature and the heat of reaction is removed by evaporation of the cooling liquid. Usually, the pressure of the cooling liquid is lower than the pressure of the gas, and a reaction vessel having a structure shown in FIG. 1 illustrating the longitudinal section thereof is used.

In FIG. 1, the upper tube plate 2 and the lower tube plate 3 are hermetically fixed to the pressure cell 1, and a number of tubes 5 are hermetically fixed to these tube plates 2 and 3. A net 4 is disposed below the tube plate 3 to support the catalyst, and the catalyst layer 6 is filled inside each tube 5. The gas compressed to the reaction pressure and preheated to a suitable temperature is fed from the gas inlet 7 through the catalyst bed 6 and from the gas outlet 8 to the next stage. While the gas passes through the catalyst bed, a conversion reaction occurs, and the heat generated by the reaction passes through the pressure cell 1 and the tube (from the cooling liquid inlet 9 through the walls of the catalyst bed 6 and the respective tubes 5). 5) It is transferred to the space between the outer tube plates 2 and 3 and the heat of reaction is removed by evaporation and boiling of the cooling liquid. Cooling liquid is discharged from the outlet 10 in the form of a vapor or liquid-vapor mixture, and the heat occupied by the vapor or liquid-vapor mixture is used, for example, to drive the turbine to compress the starting gas. This cooling liquid evaporation type reaction vessel is advantageous over the gas-gas heat exchange type reaction vessel described above for effective utilization of reaction heat and prevention of excessive rise in catalyst temperature.

However, in view of the increasing importance of energy saving and the necessity of increasing the size of a single reactor in recent years, a new problem arises in the reaction vessel of the cooling liquid evaporation type.

The first problem is that high steam temperatures and steam pressures are desired to increase the induced utilization of reaction heat. For example, when the steam generated is water vapor and it is introduced into the turbine and transformed into mechanical energy, 100 kg / cm 2 G and 480 ° water vapor expand to 40 kg / cm 2 G to recover about 50 KWH of energy per tonne of steam. However, if the pressure of the generated steam is 40 kg / cm 2 G, the energy compatible with this steam pressure is not recovered. The structure shown in FIG. 1 is not suitable for large reaction vessels in which high pressure of the generated steam is required.

The second problem is that the reaction pressure is reduced. For example, in the production of ammonia or methanol, pressures of 100 to 300 kg / cm 2 G are typically chosen for the conversion reaction. In this case, it is necessary to compress the raw material gas from the pressure level of 20 to 40 kg / cm 2 G to the level of 100 to 300 kg / cm 2 G in the gas generation step. If the pressure for the conversion reaction decreases below 100 kg / cm 2 G, the power required for this compression can be significantly reduced. Because of chemical equilibrium, it is possible to reduce the reaction pressure if a catalyst with high activity at low temperatures is available. In addition, the lower the temperature and pressure of the conversion reaction, the greater the amount of heat generated by the reaction, and the lower the activity due to excessive temperature rise. Therefore, in order to solve this second problem, it is necessary to increase the cross-sectional area of the gas passage for the flow of low pressure and large volume raw material gas and to fully control the temperature inside the catalyst bed. However, this is hardly obtained by the structure of the reaction vessel having the catalyst layer disposed in the tube as shown in FIG.

The third problem arises with the increase in the size of a single reactor. In particular, in the reaction vessel shown in FIG. 1, the tube 5 is hermetically fixed to the tube plates 2 and 3 by welding or other means to prevent leakage between the cooling medium and the effluent gas at different pressures. It is also necessary to secure the tube plates 2 and 3 to the pressure shell 1 in an airtight manner. However, since the temperature of the tube 5 is different from the temperature of the pressure shell 1, the vertical length between the tube plates 2 and 3 changes because the thermal expansion during operation is different. Even if a metal material having a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the material of the pressure cell 1 is used as the tube 5 as described in Japanese Laid-Open Patent Publication No. 49707/73, a large thermal expansion stress is applied to the tube plate 2 ) And (3). This heat capacity increases with increasing diameter and length of the reactor. Thus, the design of large reactors becomes difficult.

Another problem is that from the viewpoint of energy saving, which is pointed out in the related art, when the pressure on the cooling medium side rises and the pressure on the outflow side decreases, the thickness of each pressure cell 1, tube plate 2 and tube 5 increases. In the case of large reaction vessels, this results in serious economic disadvantages.

It is an object of the present invention to provide an improved process wherein gas completion is brought into contact with and reacted with a solid catalyst.

Another object of the present invention is to provide an improved process for catalytic gas-phase reaction with improved heat recovery.

It is another object of the present invention to provide an improved reaction vessel for a reactant gas feed in contact with a catalyst.

It is yet another object of the present invention to provide an improved reaction vessel for catalytic gas phase reactions comprising a heat recovery system with improved utilization of the heat of reaction.

Another object of the present invention is to provide an improved reaction vessel for catalytic gas phase reaction in which an optimum temperature distribution in the catalyst bed can be obtained.

Still other objects of the present invention will become apparent from the following description.

According to the invention there is provided the following process and apparatus for the catalytic gas phase reaction. That is, this process is a process for contacting and reacting a gaseous raw material with a granular catalyst layer formed in a vertical cylindrical reaction zone, wherein the gaseous raw material is substantially radially reflected through the catalyst layer in which an elongated cooling zone having a small diameter is arranged vertically. In order to remove heat generated by the reaction in the catalyst bed, a cooling medium is passed through the cooling zone to obtain an optimum temperature distribution in the catalyst bed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. An outline of the reaction vessel according to the invention will now be described with reference to FIG. 2. The gas compressed to a predetermined pressure and preheated to an appropriate temperature is introduced into the cylindrical reaction vessel from the gas inlet 7. After the pressure is homogenized in the space 13 defined by the partition wall 22 inside the pressure cell 1, the gas is deposited on the peripheral catalyst receiver 4-0 disposed adjacent to the inner surface of the pressure cell 1. It passes through a plurality of holes formed and falls into a space having an annular horizontal portion on the side of the inner surface of the pressure cell 1. The gas is then introduced into a catalyst bed filled in a space formed between a plurality of vertically arranged cooling tubes and a conversion reaction is performed while the gas is moved substantially horizontally toward the center. The reacted gas then passes through holes formed on the inner catalyst receiver 4-1 disposed adjacent to the inside of the cooling tube of the groove, which is located closest to the middle of the reaction vessel. The gas is collected in the central equalization space 14 formed at the center of the reaction vessel and separated from the upper space by the partition wall 21 and discharged from the reaction vessel through the gas outlet 8.

The cooling medium maintained at a predetermined temperature and pressure is introduced into the annular first distribution pipe 17 from the inlet 9 in the form of a rising stream, and then distributed and connects the pipe 23 connected to the first pipe piping 17. Is introduced into a plurality of second distribution pipes 18 arranged concentrically. The cooling medium then rises into a plurality of cooling tubes 15 connected to the second distribution pipe 18. The cooling medium rising in each cooling tube 15 absorbs the heat generated by the conversion reaction in the catalyst layer disposed outside the cooling tube 15, and a part of the cooling medium is evaporated and a gas-liquid mixture is formed. The gas-liquid mixture is then introduced into a plurality of collection tubes 19 concentrically arranged above the catalyst bed and collected in the second collection tube 20 via a tube 24 connected to the first collection tube 19. . The cooling medium is then discharged from the reaction vessel through the cooling medium outlet 10. The cooling medium discharged from the reaction vessel in the form of a gas-liquid mixture is introduced into the gas-liquid separator and separated into vapor and liquid. The liquid is returned to the inlet 9 for recirculation naturally by force without the cooling or by gravity without using the pump. Since this step is carried out according to a known method, this step is omitted in FIG.

The features of the present invention described above will now be described in detail.

The first feature of the present invention is that although the tube bundle is used for the removal of the heat of reaction, the tube plate is not used. If tube plates are used in the aforementioned arrangement of cooling tubes according to the present invention, thick, high quality materials with high tensile strength should be used for the tube plates, forming holes in the tube plates and inserting the tubes through these holes. A decent task is required, such as welding a tube sheet to a pressure cell. In the present invention, the material to be used for the tube sheet can be saved and many process steps can be reduced.

A second feature of the invention is that the cooling passages formed mainly by the tubular members do not need to be fixed to the pressure cell and the known leak-tight stretching means of the expansion bellows system or the gland system is the cooling medium inlet 9 and outlet 10. ) Is disposed only in the portion penetrating the upper and lower rit (rid) of the pressure cell (1). Since the diameter of this part is considerably smaller than the diameter of the joint of the pressure cell 1 and the tube plate 2 or 3 on which this expansion means should be placed, this expansion means can be used very easily in the present invention.

A third feature of the invention is that the temperature, ie temperature distribution, of each position of the catalyst bed along the flow direction of the gas can be very close to the optimum value in the conventional reaction vessel shown in FIG. In particular, in the known reaction vessel shown in FIG. 1, the outer surface of each tube 5 is in contact with a cooling medium maintained at boiling temperature and the difference in boiling point at each position in the vertical direction is very small.

Therefore, even if the amount of heat generated by the reaction changes at each position as the gas flows into the catalyst layer 6 of each tube 5, the heat transfer area at each position is substantially equal, so that the temperature at each position in the catalyst layer is predetermined. It is not possible to design the reaction vessel to remain at the level. In contrast, in the reaction vessel according to the invention, since the gas passes through the catalyst bed in a horizontal direction across the cooling conduit 15 at substantially right angles, the temperature distribution at the angular catalyst position along the gas stream differs between the respective catalyst positions. The optimum level can be maintained by appropriately arranging the number and diameter of the cooling tubes disposed at each catalyst position having a different distance from the center of the reaction vessel to generate the activity. This feature is very important, with the advantage that any amount of gas can be reacted at a high conversion rate using a reduced amount of catalyst and the size of the reaction vessel can be reduced.

A fourth feature of the invention is that the material thickness of the pressure cell 1 or the cooling tube 15 is reduced when the pressure of the cooling medium is raised to save energy as described above and the gas pressure for the conventional reaction is reduced. Can be made much smaller than in the structure shown in FIG. 1 and the material cost is significantly reduced.

The fifth feature of the present invention is that the catalyst and the filling and discharging can be carried out very easily. In the structure shown in FIG. 1, if the catalyst is above the tube plate 2 of the packed bed of the catalyst, the cooling of the catalyst in this part is insufficient and the temperature is raised in this part, which adversely affects the strength maintenance of the tube plate. If the amount of catalyst charged in each tube 5 is not uniform, deflection is caused in the gas stream. Therefore, in the conventional reaction vessel, it is necessary to charge the catalyst equally metered in the amount of each tube. In contrast, in the reaction vessel according to the present invention, the distance between the main surfaces of each two adjacent tubes is larger than the diameter of the catalyst particles. In the case of a catalyst having a conventional particle size, filling can be easily accomplished by introducing only the necessary amount of catalyst from the catalyst feed opening 25, which will be shown in FIG. In the filling step, even if the catalyst is present in the upper space above the first collecting pipe 19, the gas rarely passes through this space, so no problem occurs and any cooling capacity is secured by the pipe 24. . In the catalyst discharge step, in the conventional reaction vessel shown in FIG. 1, a large amount of catalyst is connected to the gas outlet even if the attachment position of the gas outlet is changed and the catalyst discharge opening is disposed at the bottom when the catalyst storage network 4 is brought out. It is very difficult to prevent intrusion into large diameter gas discharge tubes. Therefore, it is necessary to discharge this large diameter gas discharge tube and recover the catalyst from the tube. In contrast, in the reaction vessel according to the present invention such troublesome work is not necessary and the catalyst can be discharged directly from the reaction vessel through the catalyst discharge opening 26.

Specific features of embodiments of the present invention will now be described in detail. A first particular feature of the invention is in the direction of passage of the gas through the catalyst bed. In the present invention, as described above, the gas passes through the catalyst bed substantially horizontally from the periphery toward the center, as well as the gas passing substantially through the catalyst bed in the reverse direction, ie from the center toward the periphery, substantially horizontally. Embodiments may also be employed. Whether the former or latter examples are employed, dependence of the chemical equilibrium final concentration of the product on the main and side reactions, the migration and side reactions on pressure and temperature, the degree of influence of the flow rate, the catalyst to enhance the main and side reactions The composition and temperature of the gas in the active phase and the amount of heat generated and removed in each part of the catalyst bed are determined by various factors such as the kind. By adopting the special arrangement of the cooling tubes described above, the optimum temperature distribution in the catalyst bed along the gas advancing direction which minimizes the amount of catalyst required to achieve the desired concentration of product at the outlet of the catalyst bed can be determined depending on these factors. In other words, the size of the reaction vessel can be reduced according to the present invention. For example, when the gas volume is reduced as the reaction proceeds or the catalyst activity is drastically reduced as the gas passing through the catalyst bed increases, the reaction rate decreases as the reaction proceeds. In view of this fact, when the same conversion product is obtained from the source gas by using the same catalyst in the conventional reaction vessel shown in FIG. 1, the gas passage rate is high at the inlet of the catalyst layer where the product concentration is very low. Therefore, the catalytic activity cannot be effectively utilized, and although the passage rate of gas is low at the discharge portion of the catalyst layer, it is not necessary to increase the amount of catalyst charged in this portion because the reaction rate cannot be increased because the amount of reaction product formed increases. There is. In the conventional structure shown in FIG. 1, in the introduction portion where a relatively large amount of heat is generated, the cooling heat transfer area per gas amount is smaller than the cooling heat transfer area of the discharge portion with a small amount of reaction heat, so that the optimum heat transfer area for the introduction portion is If adopted, the heat transfer area of the discharge becomes excessive, thus causing a loss of catalyst amount or heat transfer area.

In contrast, if an embodiment in which gas passes through the catalyst bed from the periphery towards the center is adopted for the reaction vessel according to the invention, in the first stage of passing through the catalyst bed, catalytic activity is most effectively exerted at low gas velocities, The reaction is enhanced with a smaller amount of catalyst in the conventional reaction vessel shown in FIG. 1 and a sufficiently large heat transfer area per unit amount of gas is ensured for the removal of heat generated by the reaction. Further, since the reaction vessel is arranged so that the amount of catalyst and the heat transfer area decrease as the reaction heat and gas volume generated as the reaction proceeds, the optimum cooling heat transfer area can be arranged at each position of the catalyst bed. That is, the temperature distribution in the catalyst layer can be selectively set. In particular, a temperature distribution that minimizes the amount of heat transfer and the amount of catalyst required to obtain any amount of conversion product as a whole can be realized depending on the type of chemical reaction and the catalyst properties, which, as pointed out above, are closely related to the design of the reaction vessel. There is a relationship. And the size of the reaction vessel can be reduced. When the chemical equilibrium concentration of the conversion product with the change in temperature is small, the decrease in gas volume as the reaction proceeds or the change in catalyst activity due to the change in gas passage rate is small, and the gas is moved from the center to the periphery. Other embodiments to be passed are adopted. In this embodiment, the temperature of the gas supplied to the center portion is kept at a low level as permissible from the viewpoint of the catalytic activity, and the cooling tube is not disposed near the gas inlet of the catalyst bed, but the cooling tube is the catalyst The gas temperature is placed at a position following the position where the gas temperature is raised to an acceptable upper level for the catalyst by the heat of reaction so that the gas temperature is not further increased at the position. By this arrangement, the rate of gas passing through the catalyst bed is reduced in the final stage of the reaction where the concentration of the conversion product is increased, as a result the reaction is completed in a short time and the amount of catalyst and heat transfer area can be reduced.

A second particular feature of the invention lies in the arrangement of the cooling tubes. As pointed out above, in the present invention, the cooling tubes are arranged according to the type of conversion reaction and the characteristics of the catalyst used so that the optimum temperature distribution can be obtained along the radial direction in the catalyst bed. In this reaction vessel in which the gas flows in the radial direction, the flow amount of the gas in each radial direction is preferably equal. The presence of cooling tubes in the catalyst bed affects the gas flow. Therefore, in order to equalize the flow amount of all the radial gases, it is most preferable that the cooling tubes are arranged concentrically. The appropriate number of concentric circles on which the cooling tubes are arranged is formed depending on the amount of heat generated by the reaction and the size of the reaction vessel. The distance between the periphery of the catalyst bed and the outermost concentric circles, the distance between two adjacent concentric circles, and the distance between the innermost concentric circle and the inner circumference of the catalyst bed are the type of conversion reaction, so that the optimum temperature distribution can be generated in the catalyst bed It should be determined according to design factors such as the characteristics of the gas and the flow direction of the gas and the equivalent distance is not always adopted in the present invention. In order to enhance the effect of the present invention, it is important to adjust the arrangement density of the heat transfer area according to the position of the concentric circles by adopting cooling tubes of different diameters to remove the heat of reaction.

In the present invention, the flow amount of the cooling medium should be equal between the cooling tubes arranged on one concentric circle. In this respect, it is not preferable that the cooling tubes are arranged horizontally or inclined, but it is preferable that they are arranged vertically.

A third particular feature of the invention lies in the manner in which the cooling medium is used. As the cooling medium, any gas, liquid and gas-liquid mixture can be used in the present invention. When gas is used, thermal reduction is utilized. When a liquid is used, an infection utilization method in which the temperature of the liquid having one or more components is raised while maintaining the liquid state to absorb the reaction heat and a latent heat utilization method in which the liquid is evaporated by absorbing the reaction heat can be adopted. When a gas-liquid mixture is used, the two methods described above utilizing the heat loss of the liquid and the latent heat of evaporation of the liquid can be used. In this case, two ways, that is, a way in which the components of the liquid are soluble by condensation of the components of the gas (medium) and a way in which the liquid is not soluble in the condensation of steam, are considered. For example, the first mode may be applied to the combination of hydrocarbon liquid and hydrocarbon gas (medium) or water or water vapor, and the second method may be applied to the combination of water vapor and hydrocarbon liquid. When a method using direct heat is adopted, the temperature of the cooling medium at the outlet is higher than the temperature of the cooling medium at the inlet and any temperature between the top and bottom of the catalyst bed, even if any gas, liquid and gas-liquid mixtures are used. The difference is caused. In addition, the method of utilizing thermal uses a larger amount of cooling medium in the method of utilizing latent heat. Therefore, the method utilizing thermal reduction is adopted only when no specific disadvantage occurs or any heat of reaction is relatively small even if any temperature difference is observed at the top and bottom of the catalyst bed. Therefore, in the present invention, it is preferable to adopt a method of utilizing latent heat of evaporation in order to absorb heat of coagulation. Divided in the way. This approach will be described in detail later.

As mentioned above, various methods are contemplated in the manner of using the cooling medium. In any case, however, it is important to reduce the required heat transfer area, as noted above, for which the viscosity of the cooling medium inside the cooling tube must be low. In particular, in order to achieve the object of the present invention, the viscosity of the cooling medium must be lower than 1 poise. When the heat of the cooling medium is utilized, the cooling medium can flow through the cooling conduit in the form of a downward stream. However, in order to uniformly pass the cooling medium through each cooling tube, it is preferable to allow the cooling medium to flow in the form of an upstream stream by using a thermal reduction method or using a latent heat.

A fourth particular feature of the invention is the way of supporting the catalyst. As described above, in the reaction vessel of the present invention, the catalyst is not present at the outermost periphery and the central portion, and there must be a space for gas to pass between the two portions. Therefore, when the catalyst is filled from the catalyst feed opening 25 shown in FIG. 2, the catalyst receiver must be arranged so that the catalyst particles do not penetrate into these two spaces. One catalytic receiver should be arranged for each peripheral and central part. However, the method of arranging the catalytic receiver in the periphery is slightly different from the method of arranging the catalytic receiver in the center. The following three methods for arranging the catalytic receiver in the periphery may be adopted.

According to the first method, the cylindrical plate 4-2 having the through holes 4-4 in which the number and the opening area are arranged so that the required amount of gas can pass as shown in FIG. Is detachably attached to the inner circumference of the pressure cell 1 at any distance from the inner surface of the pressure shell.

These support plates are arranged along the inner circumferential surface of the pressure shell 1 and spaced apart from each other by a distance necessary to allow the passage of gas. One or more webs 4-3 with appropriate mesh numbers are attached to the inner circumferential surface or the outer circumferential surface of the perforated plate 4-2 so that a catalytic receiver is made on the inner circumference of the pressure cell. The bottom of the cylindrical porous plate 4-2 reaches the bottom head of the pressure cell 1 so that the top of the porous plate 4-2 extends slightly beyond the top end of the first collecting pipe 19 for the cooling medium. . In order to prevent the short passage of gas, the through hole 4-4 or the web 4-3 is preferably not located in any area above or below the porous plate 4-2. In this method, the structure of the catalytic receiver is very easy, and the catalytic receiver is conveniently used.

According to the second method, the catalyst receiver is fixedly arranged in the cooling tube 15-1 of the groove which is disposed on the outermost concentric circle along its periphery or inner circumference in substantially the same manner as in the first method according to the second method. .

According to the third method, the perforated plate 4-2 having the through-hole 4-4 in which the opening area and the number are arranged so that the required amount of gas can pass through as shown in FIG. If the network 4-3 is arranged along the inner circumference of the grooved cooling conduit 15-1 located on the innermost concentric circle to connect two adjacent cooling conduits, the mesh 4-3 is operated in the same manner as the first or second method. It is arrange | positioned on the inner side or outer side of the porous plate 4-2.

In each of these three methods, the relative attachment positions of the porous plate 4-2 and the network 4-3 shown in FIGS. 3, 4 and 5 may be reversed. According to the second and third methods, the process for the production of the catalyst receiver is facilitated.

A catalytic receiver to be placed in the center will now be described. The method for arranging the catalytic receiver in the central part shown in FIG. 3 corresponds to the first method for arranging the catalytic receiver in the periphery. According to this method, a suitable number of nets 4-3 having a suitable mesh number are cylindrical porous plates having a suitable number of holes 4-4 having a suitable opening area and a partition plate 21 attached thereon. It is fixed to the circumferential or inner circumferential portion of (4-2), and the assembly is attached to a portion where the gas discharge nozzle 8 protrudes into the pressure cell 1 or is fixed to this portion by welding or the like. This method is advantageous by the use and manufacture of catalytic receivers. And a method corresponding to the second and third methods for disposing a catalyst receiver in the periphery may be practically adopted. In particular, the cylindrical porous plate 4-2 having the through-hole 4-4 arranged as the opening area and the required number of gases passes as shown in FIG. 6 has a grooved cooling tube arranged on the innermost concentric circle. It is disposed along the periphery or the inner circumference of (15-2), and the net 4-3 is disposed adjacent to the inner or outer side of the porous plate 4-2, so that a catalytic receiver for the center portion is made. Then, the Grufu cooling tube 15-2 located on the innermost concentric circle has an appropriate number of through holes 4-4 having an opening area in the same manner as in the catalytic receiver for the periphery shown in FIG. A method of connecting to each other by a band-shaped plate 4-2 having a) may be adopted, and the network 4-3 is fixed along the periphery or inner circumference of the groove of the tube 15-2 to form a catalyst for the central portion. The receiver is created. On each of these catalyst receivers for the center portion, a litt 21 as shown in FIG. 7 must be attached to the top of the catalyst receiver for the center portion. The positional relationship with respect to the first and second collection tubes 19 and 18 of the at least one web 4-3 of the bottom and top ends of the catalytic receiver for the through hole 4-4 and the central portion is determined by the peripheral portion. It is substantially the same as in the catalytic receiver for.

The first advantage obtained by the above-described arrangement of the catalytic receiver facilitates the process for manufacturing, and the second advantage is each of two phosphorus tubes 15-1 or 15 located on the innermost or outermost concentric circles. The distance between -2), the opening area of the through hole formed on the plate 4-2, and the distribution of the through hole can be selectively changed and adjusted so that the amount of gas passing through the arrangement of only one wall surface is It is possible to be uniform with respect to the height and radial direction of each catalyst layer without using two wall surfaces defining the catalyst side on the gas inlet or outlet side as described in 5925/66. When the above-described catalyst filling method is adopted, depending on the nature of the catalyst used, a number often occurs in which the catalyst particles are not charged with uniform density through the catalyst bed. In this case, the function of controlling the flow rate of the above-mentioned gas is arranged in concentric circles with a small distance between each cylindrical perforated plate of the catalytic receiver for the center and the periphery and the perforated cylinder for controlling the flow rate of the gas or each two adjacent tubes. Cooling tubes are arranged in one or two middle portions between the periphery of the catalyst bed and the inner circumference. The shape of the hole formed on this porous cylinder for controlling the flow amount of gas is not particularly important, but a circular hole is preferable from the viewpoint of ease of manufacture.

A fifth particular feature of the invention lies in the arrangement of the dispensing and collecting tube. In some cases, the total number of cooling tubes 15 is small, but in many cases multiple cooling tubes 15 are used. When the total number of cooling tubes 15 is small, the entire cooling tube can be connected to the first distribution pipe 17 shown in FIG. Thus, the second distribution pipe 18 does not need to be disposed in this case. However, when a plurality of cooling tubes 15 are arranged and the entire cooling tube cannot be contacted with the first distribution pipe 17, the second distribution pipe 18 is disposed and some or all of the cooling pipes 15 are separated. The second distribution pipe 18 is connected and the second distribution pipe 18 is connected to the first distribution pipe 17 through the connection pipe 23. When too many cooling tubes 15 are used, the foot can be applied to large reaction vessels by arranging the third and fourth distribution lines in the manner described above. In the embodiment shown in FIG. 2, a second distribution pipe is arranged. Of course, the present invention is not limited to this embodiment shown in FIG. When this distribution tube is arranged, it is easy to manufacture, and the distribution vessel of each grooved is arranged concentrically at sufficient intervals to connect them to the cooling tube 15 and the connecting tube 23, and the reaction vessel is conveniently used. It is preferable as it is. In order to uniformly distribute the cooling medium in the plurality of cooling pipes 15, the two or more inlet pipes 9 and the first distribution pipe 17 for introducing the cooling medium into the first minute pipe are divided into two parts. At least two connecting plates 23 for connecting to the pipe and at least two connecting pipes for connecting the second distribution pipe to the third distribution pipe should be arranged in a symmetrical position with respect to the center side.

The collection tube 19 is arranged in the same manner as described above with respect to the distribution tube. When the number of cooling tubes is relatively small, all the cooling tubes can be connected to one collecting tube. However, when a plurality of cooling tubes are arranged, it is necessary to arrange the first, second and third collecting tubes concentrically and to arrange one or more connecting tubes 24 to connect the collecting tubes. From the standpoint of ease of manufacture or use, it is desirable that the number of collection tubes is gradually reduced within each groove. However, in the embodiment of FIG. 2, in order to distribute the cooling medium evenly to all the cooling tubes, a final collecting tube is disposed, and the height and shape of the final collecting tube 20 is a proper flow rate in the final collecting tube 20. It is usually desirable to determine that this is to be maintained. When the reaction vessel is very large and the heat of semi-melting is relatively low, the above-described method of utilizing the evaporation of the cooling medium is used, and the structure is preferably adopted in which the function of separating the liquid from the vapor is given to the final collecting tube. A tube 28 for strengthening the separated liquid, indicated by the broken line, is arranged in the gas space in the center. The tube 28 is connected to the first distribution line 17 through one or more connecting tubes 29 for natural circulation of the cooling medium in the reaction vessel. Only the vapor of the cooling medium is withdrawn from the cooling medium outlet 10 and an amount of cooling medium corresponding to the amount of steam withdrawn from the outlet 10 is supplied from the cooling medium inlet 9. In this embodiment, the structure can be simplified and the operation can be conveniently performed as compared to the embodiment where the vapor-liquid separator is disposed outside the reaction vessel, and the liquid remaining after the separation of the steam is recycled and naturally or by gravity The pump is forcibly returned to the cooling medium inlet 9 through the liquid drop tube. The sealed container insulated from the pressure cell is used as a structure for branching or collecting cooling medium instead of the tubular member described above.

A sixth particular feature of the invention lies in the means for relieving thermal stresses due to thermal expansion differences. In the present reaction vessel according to the present invention, as described above, the temperature difference of the catalyst layer during operation is considerably smaller than in the conventional reaction vessel. However, any temperature difference is inevitably observed. Thus, for example, each tubular structure constituting a cooling structure such as the distribution pipes 17 and 18, the connection pipe 23, the cooling pipe 15, the collection pipes 19 and 20, and the connection pipe 24, for example. A slight thermal stress is caused by the temperature difference of the joints of the members. Since the cooling structure is constituted by tubular members, such thermal stress is dispersed and cut by forming curved portions in each tube. Therefore, a cooling structure assembled by a tube having a curved portion is usually preferred. Even if there is a temperature difference between the pressure cell 1 and the cooling structure, the generation of thermal stress due to this temperature difference can be achieved by using a known expansion gas leak prevention means of expansion bellows or gland type as shown in FIG. With respect to cooling structures such as the cooling medium inlet 9 and the cooling medium outlet 10, the cooling medium inlet and outlet tubes can be left completely by adapting to the part passing through the pressure cell 1.

A seventh particular feature of the invention lies in the preheating manner of the source gas to be introduced into the reaction vessel. When the reaction vessel of the present invention having the above-described structure is used, all the heat of reaction can be absorbed in the cooling medium, and the temperature of the reaction effluent gas leaving the catalyst layer corresponds to the outlet temperature of the catalyst layer in which the above-described temperature distribution occurs. The temperature is slightly higher than the temperature of the source gas at the inlet of the catalyst bed. Thus, the gas to be introduced into the catalyst bed can be preheated by conducting heat exchange between the lamp leaving the catalyst bed and the gas to be introduced into the catalyst bed. This heat exchange may also be accomplished using a known heat exchanger disposed outside the reaction vessel. And, heat exchange can be achieved by placing a heat exchanger in the reaction vessel internal space as shown in FIG. In particular, in the embodiment shown in FIG. 8, a known cylindrical shell and tube heat exchanger is arranged in the space at the center of the reaction vessel. The heat exchanger is composed of a plurality of tubes 30 as a main member, a tube plate 31 on which the tubes 30 are fixed, and a cell 32 of the heat exchanger.

In the embodiment shown in FIG. 8, the starting gas for switching is from the gas inlet 7 of the cylindrical shell and tube heat exchanger defined by the outer surface of the tube 30, the tube plate 31 and the inner cell 32. It is introduced into the space on the cell side, and the heat exchange is performed between the introduced gas so introduced and the hot gas extracted from the outlet of the catalyst layer passing through the tube 30. Passing through the preheated gas distribution pipe 34, it is introduced into the catalyst bed from the inlet space 13 of the catalyst bed in the manner described above. The gas discharged from the catalyst layer into the outlet space 14 is introduced into the inside of the tube from the bottom portion thereof, and heat exchange is performed between the discharge gas and the starting gas flowing on the cell side to lower the discharge gas temperature. The discharge gas is then discharged from the reaction vessel through the outlet space 33 and the gas outlet 8.

When the preheat heat exchanger is used as described above, the pressure difference between the outside and the inside of the tube plate 31 is mainly due to the pressure loss caused when passing through the catalyst bed. This pressure difference is so small that it does not bring any special disadvantages due to the arrangement of the tube plates 31.

Another example of the method of preheating the feedstock gas to be introduced into the reaction vessel according to the invention is that the feedstock gas is first introduced over an insulated preliminary reaction and the gas introduced therein is converted to some extent and the temperature is increased and then the temperature is increased. The increased gas is introduced into the present invention of the reaction. The source gas usually contains trace amounts of catalyst poisons. The degradation due to the catalyst poison itself cannot be prevented even in the reaction vessel according to the present invention or in the conventional reaction vessel. However, introduction of source gas into a small insulated pre-reactor absorbs the total amount of catalyst poison in the catalyst bed of the pre-reactor and greatly extends the catalyst life in the reaction vessel according to the present invention serving as the main reaction vessel.

The primary purpose of the insulated preliminary reactor described above is to remove the catalyst poison and increase the feedstock gas to a temperature low enough to be introduced into the main reaction vessel by converting as appropriate. Thus, the preliminary reactor is considerably compact in structure and simple in comparison with the reaction vessel according to the present invention as the main reaction vessel.

The source gas discharged from the preliminary reactor is cooled to a temperature suitable for the source gas to be supplied into the main reaction vessel so that the temperature of the source gas does not become too high.

The catalyst life in the main reaction vessel is greatly extended, and the operating efficiency of the plant as a backlog containing a process for preparation of source gas is increased by an operation process in which only the operation of the prereactor is stopped when the catalyst in the prereactor is chlorinated. The feedstock gas is introduced directly into the main reaction vessel only during the exchange of the heat exchanged catalyst.

It is preferred that a set of preliminary reactors be provided for use alternately.

Any material that can resist various stresses induced under actual applied operating conditions such as switching pressure, switching temperature, cooling medium pressure and cooling medium temperature and which does not adversely affect the conversion reaction can be used as the structural material of the reaction vessel.

Application of the reaction vessel according to the invention will now be described. The reaction vessel according to the present invention can be applied to a chemical exothermic reaction in which the starting material introduced into the catalyst bed and the reaction product leaving the catalyst bed are maintained in gas under temperature and pressure conditions causing a conversion reaction and generate an appropriate temperature distribution in the catalyst bed or It is desired to perform strict temperature control through the catalyst bed.

As such a chemical exothermic reaction, for example, the production of ammonia from the starting gas containing hydrogen and nitrogen, the production of methanol, methane or hydrocarbons having 2 or more carbon atoms from the starting gas containing hydrogen and carbon monoxide and / or carbon dioxide, Preparation of hydrogen from starting gas containing water vapor and carbon monoxide, Preparation of saturated chlorine-substituted hydrocarbons such as chloromethane or ethylene chloride containing starting gas containing hydrocarbon and chlorine, Oxidation from starting gas containing hydrocarbon and oxygen Oxidation reactions to produce ethylene, maleic anhydride or phthalic anhydride, oxychlorine substitution reactions to produce unsaturated chlorine-substituted hydrocarbons such as secreted chloride from starting gases containing hydrocarbons and chlorine and / or hydrogen chloride and oxygen, hydrocarbons, ammonia And acrylics from starting gases containing oxygen Ammoxidation to prepare cyanogen compounds such as nitrile or cyanic acid, hydrogenation reactions to produce saturated hydrocarbons such as cyclohexane from starting gases containing unsaturated hydrocarbons and hydrogen, starting gases containing unsaturated hydrocarbons and saturated hydrocarbons Alkylation reaction for producing isooctane or itylbenzene, and oxidation reaction for producing formaldehyde and the like from a starting gas containing an oxygen-containing organic compound and oxygen. When the reaction vessel according to the present invention is used, various advantages are obtained by improving the utilization efficiency of the reaction heat, such as saving energy through all the process steps, convenience of design of the reaction vessel, and reduction of material cost for producing the reaction vessel.

In addition, in each of the above-described chemical reactions, the temperature distribution in the reaction layer is optimized and the temperature can be accurately controlled through the catalyst layer, thereby increasing the yield of the undesired product, suppressing the formation of by-products, and extending the life of the catalyst. have. The kind of catalyst is not particularly important when the reaction vessel according to the present invention is applied to the above-mentioned chemical reaction, and a catalyst suitable for the intended reaction can be used. And the capacity of the reaction vessel can be increased by arranging two or more catalysts with different catalyst properties such that the gas contacts the different catalysts in the catalyst bed. In particular, enormous technical and economic advantages can be obtained when the present invention is applied to the mass production of ammonia or under a pressure of less than 100 kg / cm 2 G.

The use of the heat of reaction absorbed by the cooling medium will now be described. The heat of reaction is utilized in various fields.

In the case of a method of utilizing the heat of the cooling medium, the reaction vessel may be used to raise the temperature of the starting material to be used in the step requiring high temperature. Also in the case of utilizing the latent heat of evaporation of the cooling medium, the heat of reaction absorbed is similarly utilized. For example, in the preparation of ammonia from naphtha, a mixture of naphtha in high pressure steam or hot water is used as the cooling medium to heat the vapor or evaporation naphtha in the reaction vessel according to the invention, so that hot gas is used as a hook material of ammonia. Used as starting material for the step of preparing hydrogen. In the case of a method utilizing latent heat of evaporation, the heat of reaction is utilized for other purposes. For example, the vapor is separated from the liquid and then introduced into another step for heating other materials directly or indirectly. The heat of reaction is then converted to mechanical power after heating or directly by utilizing the pressure of the steam in the turbine. The steam is then utilized to compress the gas to be introduced into the reaction vessel. The boiling point of the cooling medium to be used in the reaction vessel may be adjusted to a level slightly lower than the catalyst bed temperature determined by the characteristics of the catalyst used and the type of conversion reaction by adjusting the flow rate or inlet conductivity of the cooling medium or the pressure applied to the cooling medium. Can be. Any cooling medium that is hardly degraded by heat during operation and has no corrosion on the material of the reaction vessel can be used in the present invention. In the case of utilizing the latent heat of evaporation of a cooling medium, from the viewpoint of the effective utilization of the energy occupied by the vapor of the cooling medium, as a cooling medium, aromatic compounds such as water, aromatic hydrocarbons or aliphatic hydrocarbon fractions, chlorinated aromatic hydrocarbons Or diphenyl oxide or a mixture thereof is preferably used. When such a cooling medium is used for the method utilizing the latent heat of evaporation, the temperature through the catalyst bed can be strictly controlled by appropriately adjusting the boiling point of the cooling medium and the pressure of the cooling medium. In this method, the upper limit of the allowable pressure of the cooling medium is about 150 kg / cm 2 G for the above-mentioned natural ring or about 200 kg / cm 2 G for the aforementioned forced circulation. If the pressure exceeds this threshold level, the cooling capacity of the cooling tube is reduced.

In summary, the present invention is as follows.

1.The pressure in the cooling tube is controlled to a predetermined level such that the cooling medium is a liquid substance at a temperature of 50 ° C. or lower and a liquid or vapor-liquid mixed phase having a desired boiling point temperature is produced.

2. characterized in that the cooling medium is liquid at a temperature below 50 ° C. and the pressure in each cooling zone consisting of a plurality of cooling tubes is squeezed to a predetermined level such that a liquid or vapor-liquid mixed phase with a desired boiling point is produced. and,

3. The cooling medium is characterized by water,

4. characterized in that the pressure of the cooling medium is adjusted to a pressure of less than 200kg / ㎠G,

5. Nitrogen and hydrogen are reacted at a pressure of less than 100kg / ㎠G to form ammonia,

6. is characterized in that hydrogen and carbon monoxide and / or carbon dioxide form methanol under reaction at a pressure of 100 kg / cm 2 G or less;

7. The gaseous raw material reacts in a preliminary reaction zone including the same catalyst as the catalyst without removing the heat of reaction, thereby raising the temperature of the gaseous raw material and removing the catalyst poison contained in the gaseous raw material,

8. The cylindrical cell in which the reaction vessel is vertical; Inlet for gaseous raw material and outlet for reaction effluent gas; Inlet and outlet for cooling medium; A cylindrical weekly catalytic receiver that is open at both ends and has a plurality of holes through its walls and is located vertically in the interior of the cell; A catalyst having a plurality of holes in its wall and positioned vertically in the interior of the peripheral catalyst receiver, the catalyst having a granular catalyst layer filled in the space between the peripheral and the central catalyst receiver; A plurality of vertically expanding cooling tubes whose one end is connected to the inlet for the cooling medium and the other end is connected to the outlet for the cooling medium; A first peripheral equalization space between the cell and the peripheral catalyst receiver; And a second equal space consisting of a central equalization space inside the central catalyst receiver, which is distinguished from the first space by a partition located at one end of the central catalyst receiver, wherein the gaseous raw material is mainly radially removed while removing the generated reaction heat. Inlet for the gaseous raw material is connected to one of the spaces to obtain an optimum temperature distribution along the radial direction and then discharged through an outlet for the reaction effluent gas connected to the other spaces,

9. The center of the cooling tube is arranged on at least one circle, the center of which is substantially co-perpendicular to the center of the reaction vessel, at least in the horizontal section of the catalyst bed,

10. The reaction vessel further comprises a tubular member for distributing the cooling medium in the cooling conduit, collecting the cooling medium from each cooling conduit, and discharging the used cooling medium,

11. It is characterized by the use of cooling tubes of different diameters,

12. A reaction vessel is used in which at least one layer of tube plates is located between the surrounding and central catalyst receivers,

13. The volume between the edge of the catalyst bed and the outermost concentric circle with the cooling tubes arranged, the volume between two adjacent concentric circles with the cooling tubes arranged, and the volume between the innermost concentric circle with the cooling tubes arranged and the inner circumference with the catalyst bed The radial direction is scaled to the already scheduled size used,

14. The reaction vessel is characterized in that the reaction vessel is actually used arranged in a plurality of concentric circles,

15. A method of exothermic reaction of a gaseous raw material, characterized in that a cooling vessel is arranged on each circumference so that the reaction vessel is used such that the volume between every two adjacent tubes is adjusted to a predetermined size on each concentric circle.

Claims (1)

In a process in which a gaseous raw material is brought into contact with a granular catalyst layer in a vertical cavity cylinder for reaction, an elongated cooling fan passes substantially radially through the gaseous material through the vertically arranged catalyst layer. And a cooling medium is passed through the cooling tube to remove heat generated by the reaction in the catalyst layer, and a cooling medium is passed through the cooling tube to remove the heat generated by the reaction in the catalyst layer. A method of exothermic reaction of gaseous raw material material, characterized by obtaining an optimum temperature distribution along a gas flow path.

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