JPS61138527A - Water supply system for cooling reactor - Google Patents

Abstract

PURPOSE:To diminish the load of the titled plant by mixing the replenished water in accordance with the generated amount of steam with the pressurized water of saturated temp. which is introduced through a downcast pipe of boiler, regulating the temp. and thereafter supplying it to a water inlet nozzle of reaction unit in a rear flow side. CONSTITUTION:The temp. of water fed to the inside of a shell 14 through a nozzle 16 which is provided to a lower part of the shell 14 of a reaction unit B in a rear flow side is regulated to the temp. lower by about 10-100 deg.C than the temp. (satd. temp.) of water incorporated in a steam drum 17 in the position of the nozzle 16. Thereby it is remarkably valuable industrially that the concn. of reaction product in a lower end of the reaction tubes 7 (plural numbers) i.e. in the gas after finishing the reaction is increased. Still more a feeding method of the replenished water and a heat exchanger 23 are provided owing to preset the temp. of water which is fed to the inside of the shell 14 through the water inlet nozzle 16 provided to the low part of the shell 14 to the some conditions.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to methanol synthesis using a mixed gas of hydrogen and carbon monoxide (and carbon dioxide) (from multiple elements in the presence of a solid particulate catalyst). The present invention provides an improved water supply facility for cooling a reactor used for the purpose of carrying out an exothermic reaction of a mixed gas.

(Prior Art) For reactors used in this type of applications, various means and structures have been proposed for controlling the rise in gas temperature due to exothermic reactions during operation, but these are as shown in Figure 5. For example, as evidenced by the effect of temperature on the equilibrium concentration of methanol in the methanol synthesis reaction, as the temperature increases, the horizontal concentration of methanol decreases, impairing the economics of industrial plants. (The figure shows the case where the molar ratio of Hl and CO is 4.) However, if the reaction temperature is too low, even if a catalyst is used, the reaction rate will not reach a sufficiently high state, so it is not suitable for industrial use. It is preferable to operate within a certain appropriate temperature range, taking into consideration catalyst performance, space velocity (contact time of gas and catalyst), etc., and the present inventors have proposed that hydrogen,
- When industrially synthesizing methanol using a mixed gas containing carbon oxide and carbon dioxide as significant substances, 220 to 2
We believe that 80℃ is the appropriate temperature range, and the gas pressure (total pressure) is 50 to 300 kg/cIf.
We believe that 12G is an economically appropriate range. however,
These condition ranges may change due to future catalyst improvements, etc., and are not particularly specified.

A known example of this temperature control method structure is
There is No. 568. Each symbol in FIG. 6 is as follows.

101: Unreacted gas inlet, 102: Lower arm, 103 + upper tube sheet, 104: Steam outlet, 105: Reaction tube, 106
: Catalyst, 107 + Ciel, 108! Water, 109: Make-up water inlet, 1102 lower tube plate, 111: Lower arm, 112: Reaction completed gas outlet This known example, as shown in FIG. A pressurized mixed gas consisting of carbon dioxide, etc. was passed through a reaction tube 105 filled with a catalyst 106 from above to below to perform a °C methanol synthesis reaction, and the reaction heat was brought into contact with the outer surface of the reaction tube 105. The purpose is to maintain the gas temperature inside the reaction tube 105 within an appropriate range of conditions by removing water at an appropriate pressure and saturation temperature using the latent heat of vaporization for 10 days. Naturally,
The space velocity of the reaction tubes 105 in the tube length direction is kept constant.Although a large number of reaction tubes 105 are provided, they are omitted in FIG.

As shown in FIG. 6 (reaction tube 105 filled with catalyst 106
A method of increasing the concentration of reaction products at the reactor outlet 112 in a reactor in which a gas to be reacted is made to flow through the tube, and the outer surface of the reaction tube 105 is brought into contact with pressurized water at a saturation temperature for 10 days. As for the structure, the present inventors previously proposed a reactor in which the reactor was separated into upstream and downstream sides, and the temperature and space velocity of each were improved (Japanese Patent Application Nos. 59-144162 and 59-180727). No.)0 Regarding the contact reaction in the reaction tube of the downstream reactor, from the viewpoint of the flat methanol concentration in Figure 5, it is preferable to maintain the temperature at a low level in order to increase the reaction product concentration. The inventors also proposed a method in which the pressure of the pressurized water at the saturation temperature in contact with the outer surface of the reaction tube in the rear reactor is set to a lower value than that in the upstream reactor (Japanese Patent Application No. 1983- No. 21875).

However, when the upstream side reaction unit A and the downstream side reaction unit BK are separated, as in reaction unit 4 and the reactor shown in FIG. Because the generated water vapor pressure is different,
This is undesirable when this steam is used for purposes such as driving a steam turbine, and it is also undesirable from an operational point of view as the number of steam-water drums increases.

In addition, in FIG. 7, 104' and 104'' are steam outlets, 105' and 105'' are reaction tubes, and 109'.

IC 19'' is a supply port, 115 and 114 are tube plates, and the other parts are the same as those in FIG.

(Problems to be Solved by the Invention) It is an object of the present invention to provide a water supply system for cooling a reactor, which eliminates the problems of the conventional device described above.

(Means for Solving the Problems) Does the present invention provide a granular solid catalyst? A plurality of filled reaction tubes are placed in a plurality of reaction units' in which the upper and lower tubes are temporarily fixed. The pressurized mixed gas to be reacted with is introduced into the upstream reaction ↓ unit and transferred to the downstream reaction unit, and the space velocity of the downstream reaction unit is adjusted to the upstream reaction unit. A downstream reaction unit is installed in a curving vessel in which pressurized water whose saturation temperature is lower than that of the gas reacting in the reaction tube is brought into contact with the outer surface of the reaction tube. In order to keep the temperature of the water supplied from the water inlet nozzle installed at the lower end of the boiler shell lower than the saturation temperature, make-up water corresponding to the amount of steam generated is mixed with pressurized water at saturation temperature introduced from the boiler downcomer pipe. Desired temperature 1cy4 with t heat exchanger
The present invention relates to a water supply device for cooling a reactor, characterized in that the water is supplied to a water inlet nozzle at the lower end of a shell of a downstream reaction unit after the water has been cut.

(Function) Below, the apparatus of the present invention will be explained based on the drawings. FIGS. 1 and 2 are schematic diagrams showing embodiments of the water supply apparatus for cooling a reactor according to the present invention.

Of these, Figure 2 is the upstream and downstream reaction units? This shows an embodiment in which they are housed independently in separate shells.

Each symbol in the figure is as follows.

1.2: Tube plate of the upstream reaction unit 3: Reaction tubes (multiple pieces) of the upstream reaction unit 4: Catalyst in the reaction tube of the upstream reaction unit 5.6: Tube plate 7 of the downstream reaction unit : Reaction tube (plurality) of downstream reaction unit 8: Catalyst 9, 9' in reaction tube of downstream reaction unit: Mirror +o, +o': Mirror 11; Shell 12 of upstream-reaction unit: Upstream side Air/water outlet nozzle 13 of the shell of the reaction unit: Water inlet nozzle 14 of the shell of the upstream reaction unit: Shell 15 of the downstream reaction unit + air/water outlet nozzle 16 of the shell of the downstream reaction unit: downstream reaction Unit shell water inlet nozzle 17: Air-water drum 18.20: Down pipe 21: Make-up water pump 22: Make-up water pump outlet pipe 23: Heat exchanger 19.24 i Water inlet pipe 25.26: Air-water riser pipe 27: Gas piping 28: Water in the front i-side reaction unit shell 11 29: Water 30 in the downstream reaction unit shell 14; Air-water drum 17
In FIGS. 1 and 2, the water 28 located on the outer surface of the reaction tube 5 of the upstream reaction unit A is the water at a saturated temperature separated by the air-water drum 17, which is passed through the downcomer pipe 18 and the inlet pipe. The air/water temperature mixture containing water vapor generated by receiving and removing the reaction heat in the reaction tube 5 is supplied into the shell 11 from the °C nozzle 15 via 19Y at a saturation temperature, and is supplied to the shell 11 from the nozzle 12.
The air and water are returned to the air and water drum 17 via the outside air and water rising pipe 26'ft. The water from which steam has been separated in the air-water drum 17 flows into the downcomer pipe 18 again and repeats the circulation cycle. It is similar to a type steam generator, but the difference is that make-up water is not supplied to the steam-water drum 17.

In the downstream reaction unit B, the water 29 located on the outer surface of the reaction tube 7 is supplied to the air-water drum 17, and the separated water at saturated temperature is sent to the downcomer pipe 18.20 to the make-up water pump outlet pipe 22.
After mixing this with new make-up water supplied via the make-up water pump 21 (the amount of water corresponds to the amount of steam generated in the air-water drum 17), the water is moved to the heat exchanger 26.
The temperature is set to an appropriate temperature at node 11, and the water is supplied into the shell 14 from the water inlet nozzle 16 provided at the bottom of the shell 14 via the water inlet pipe 24. The water supplied into the shell 14 receives and removes the reaction heat of the exothermic reaction proceeding inside the reaction tube 7, thereby generating water vapor and turning it into a mixed fluid of water vapor and water. 15, the air flows into the air and water drum 17 via the air and water rising pipe 25. The water from which steam has been separated in the air-water drum 17 flows into the downcomer pipe 18. Like this, downstream fill reaction unit B
The pressure of the water supplied to the shell 14 is the same as that of the shell 11 and air-water drum 17 of the upstream reaction unit A, but water is supplied into the shell 14 from the water inlet nozzle 16 provided at the bottom of the shell 14. In order to set the supplied water temperature t, the make-up water supply method and heat exchanger 25fj! : The present invention is characterized by having the following properties, and the effects thereof will be shown below.

In the reactor of the present invention, the temperature of the water supplied into the shell 14 from the nozzle 16 provided at the lower part of the shell 14 of the downstream reaction unit B is controlled by an odor at the position of the nozzle 16, and an air-water drum 17. 10 to 10 lower than the water temperature (saturation temperature)
It is of great industrial value that by lowering the temperature by 0° C., the concentration of reaction products at the lower ends of the reaction tubes 7 (plurality), that is, in the reaction-completed gas, can be increased. Naturally, the same effect can be obtained by changing the pressures of the water 29 in the shell 14 and the water 28 in the shell 11, but as mentioned above, extracting steam at different pressures is difficult in industrial plants. However, with the apparatus of the present invention, it is possible to obtain the same water vapor pressure, and the present invention is characterized in this point.

In the present invention, the temperature of water in the shell 14 has a distribution as shown in FIG. In the figure, the water temperature at the lower end of the shell 14 is indicated by a. As the water rises inside the shell 14, its temperature increases, reaching a saturation temperature at point b, reaching point C at this temperature, and flowing out from the nozzle 15 at the upper end of the shell 14. From point a to point b, the reaction heat in the reaction tube 7 moves to the water side via the tube wall by °C, receiving and taking heat as sensible heat of the water, and from point b to point 0, the water evaporates. latent heat ℃
Naturally, from point a to point b, the temperature of the water in contact with the outer surface of the tube is low, so the gas temperature inside the reaction tube 7 is lower than the range from point b to point 0. This has the advantageous effect of increasing the concentration of reaction products in the gas at the lower end of the reaction tube 7.

FIG. 4 is a redrawing of FIG. 5 into a qualitative diagram with a constant pressure, and the gas temperature and reaction product concentration in the upstream reaction tube 3 and the downstream reaction tube 7 are entered therein. Upstream reaction tube 3
Inside, unreacted gas G is fed from point a at the upper end of the tube,
Since the reaction product a degree is small and the difference from the equilibrium concentration is large, the reaction proceeds at a high reaction rate and the amount of heat generated is large, so the space velocity χ is increased and the amount of heat generated per unit pipe length is reduced. In order to suppress the rise in gas temperature, the gas temperature is
The temperature reaches a maximum at point b, after which the temperature decreases slightly and flows out from the lower end of the upstream reaction tube 5 at point 0. In the downstream reaction tube Z, the gas flowing from the lower end of the upstream reaction tube 3 is supplied from the zero point at the upper end of the tube. Since the space velocity of the gas in the downstream reaction tube 7 is smaller than that in the upstream reaction tube 6, the gas temperature rises slightly to reach point d, and then gradually decreases. However, since the exothermic reaction continues in the tube, the reaction tube Z
The temperature will be slightly higher than the water temperature outside. In the conventionally known technology, when the pressure of water in the shells of the upstream reactor and the downstream reactor is constant, the gas temperature and reaction products are a, b, C,
It changes along five trajectories: d, e, and f, and at the temperature and reaction product concentration at point f, the reaction product concentration flows out of the reactor.

On the other hand, in the present invention, the gas temperature and the reaction product concentration are changed as shown in FIG. d, e, g
It changes according to the trajectory of ℃ and flows out of the reactor at the temperature and reaction product concentration of point g.

As described above, in the present invention, the concentration of reaction products at the outlet of the reactor is as high as the g point, but this is because the horizontal concentration increases as the temperature decreases, so the concentration of reaction products in the tube increases. This is because the difference between the gas concentration and the equilibrium concentration acts as a driving force that causes the reaction to proceed.However, even if it comes into contact with a catalyst, the reaction rate decreases as the temperature decreases, so if the gas temperature is Even if the water temperature is lowered to 10 to 100 °C lower than the saturation temperature, there is no significant effect, and in the present invention, it is industrially effective to set the water temperature on the shell side at point f to 10 to 100 °C lower than the saturation temperature. Yes 0 When the present invention is implemented industrially, the pump 2 of FIGS. 1 and 2
Preferably, the temperature of the make-up water supplied via downcomer 18.20 is lower than the saturation temperature, but if the temperature of the water supplied from downcomer pipe 18. It is impossible to always keep the amount of water supplied constant (due to plant load and liquid level control method 9 of the air-water drum 17, the amount of water supplied cannot be kept constant). Therefore, it is a major feature of the present invention that a heat exchanger 25 is provided in order to set the temperature of water supplied from the water supply nozzle 16 into the shell 14 to an appropriate condition. During steady operation, this heat exchanger 23 functions as a cooler1, and the thermal energy required for this cooling can be effectively used for preheating fluids such as gas. Setting the water temperature to a low condition is also effective in reducing the load on the heat exchanger 23.

As described above, the present invention can provide an industrially effective reactor. Although the present invention is mainly applicable to a reactor for methanol synthesis, it is also applicable to gas catalytic reactions in other applications. It is also possible to use it as a reactor. Also, is there a center tube inside the reaction tube? It is also possible to apply the present invention to a reactor having the above structure.

(Effects of the Invention) With the apparatus of the present invention, the concentration of reaction products can be increased while keeping the temperature in the downstream reaction unit low, so that the load on the plant can be reduced.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are schematic diagrams showing embodiments of a water supply device for cooling a reactor according to the present invention. FIG. 3 shows the temperature distribution of water in the downstream shell of the reaction unit according to the invention. FIG. 4 shows the relationship between reaction gas temperature and reaction product (methanol) concentration. FIG. 5 shows the relationship between pressure and temperature for methanol equilibrium concentration. FIGS. 6 and 7 are schematic diagrams of conventional devices. Sub-agent 1) Clearance agent Ryo Hagiwara - Figure 3 Shell height direction length Temperature □ Pressure 7] (α hunting)

Claims (1)

[Claims] A plurality of reaction units each having a plurality of reaction tubes filled with a granular solid catalyst fixed to upper and lower tube sheets are separated into a frontstream side and a downstream side and placed in the same shell or separate shells, The pressurized mixed gas to be reacted in the reaction tube is introduced into the upstream side reaction unit and moved to the downstream side reaction unit, and the space velocity of the downstream side reaction unit is adjusted to the upstream side reaction unit. In a reactor that is smaller than that of the reaction tube and has a saturation temperature lower than the temperature of the gas undergoing reaction in the reaction tube, pressurized water is brought into contact with the outer surface of the reaction tube. In order to keep the temperature of the water supplied from the water inlet nozzle installed at the lower end of the unit shell lower than the saturation temperature, make-up water corresponding to the amount of steam generated is mixed with pressurized water at the saturation temperature introduced from the boiler downcomer pipe.
A water supply device for cooling a reactor, characterized in that the water is adjusted to a desired temperature using a heat exchanger and then supplied to a water inlet nozzle at the lower end of a shell of a downstream reaction unit.