JPH0647521Y2 - Evaporating device for high temperature corrosive fluid and expansion joint for use in the device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an evaporator for producing a high temperature corrosive fluid such as high temperature caustic soda and caustic potash, and an expansion joint used for the apparatus. The present invention relates to an evaporation device capable of accurately measuring a corrosive fluid and an expansion joint used for the device.

[Conventional technology]

Conventionally, a high temperature corrosive fluid such as caustic soda produced in an evaporation can is taken out from the evaporation can, temporarily stored in a storage tank, and a necessary amount is taken out from this tank and is measured as shown in FIG. Such devices are known.

In FIG. 4, the evaporator 1 comprises an evaporator main body 2 and a heat exchanger 3.
And the caustic soda aqueous solution introduced from the tube 3a into the tube of the heat exchanger 3 is heated by the heating medium supplied from the tube 3b into the heat exchanger 3 to evaporate and condense the water. In the evaporator main body 2, the vapor and the concentrated liquid are separated, the vapor is discharged from the pipe 2a, and the concentrated liquid is taken out from the pipe 4. The concentrated liquid concentrated in the evaporator 1 is a high-temperature, high-concentration liquid with a concentration of 95% and a temperature of 320 ° C.
Is sent to the storage tank 5 and is temporarily stored there. Then, after being taken out from the pipe 6, cooling (not shown),
It is configured such that the amount required for the reactor in the subsequent step is measured in a state where it is cooled to room temperature by a measuring device and solidified into flakes. A spring 5b is interposed between the storage tank 5 and the support seat 5a to absorb the thermal expansion of the tube 4 due to a high temperature of 320 ° C. and prevent the evaporation can 1 from being damaged or deformed due to the thermal stress of the tube 4. Is configured. In this way, the high-temperature high-concentration caustic soda solution is once cooled to room temperature and solidified, and then weighed. This is because it cannot be used.

[Problems to be solved by the device]

In the conventional apparatus as described above, a high temperature and high concentration caustic soda solution is once cooled to room temperature to be solidified and then weighed. It is inconvenient when thrown into a container and used. That is, a step of once solidifying and liquefying, heating energy for raising the temperature to a temperature necessary for the reaction again, and the like are necessary.

The present invention has been made in view of the above problems, and provides an evaporator capable of accurately measuring a corrosive fluid such as a caustic soda solution at a high temperature and a high concentration, and further used in the apparatus. The purpose is to obtain an expansion joint that is inexpensive and has improved corrosion resistance.

[Means for Solving the Problems]

In order to achieve the above object, the evaporation device for a hot corrosive fluid according to the present invention connects an evaporator for producing a hot corrosive fluid and a storage tank for receiving the fluid with a fluid transport pipe having an expansion joint. At the same time, a storage amount measuring device is attached to the storage tank.

The expansion joint can be attached at an appropriate position on the fluid transport pipe, but it is particularly effective to install it on the fluid transport pipe attachment portion of the storage tank for the reason described below.

Further, when the storage amount measuring device is a load cell, the measurement accuracy is good and the measurement control is easy.

Then, in order to make the expansion joint used in the evaporation device resistant to corrosion and to be inexpensive, the passage pipe of the high temperature corrosive fluid is positioned in the central portion, and the joint is attached to the inlet side of one end of the passage pipe, The other end joint is loosely fitted to the passage pipe at the other end, and a bellows is attached between the inlet joint and the outlet joint so as to surround the passage pipe. The end is provided at a position projecting from the outlet side joint.

[Action]

In the evaporator configured as described above, the hot corrosive fluid produced in the evaporator is received in the storage tank, and the storage amount is measured integrally with the storage tank by the measuring device installed in the storage tank. At this time, since an expansion joint is attached to the fluid transport pipe that is connected to the tank and through which the high temperature corrosive fluid flows, the thermal stress due to the expansion of the fluid transport pipe due to high temperature is absorbed by the expansion joint and affects the tank. Is reduced and weighing is performed accurately. Therefore, the flow rate or the received amount of the high temperature corrosive fluid can be accurately measured without change.

When the expansion joint is installed in the fluid transport pipe mounting portion of the storage tank, the thermal stress due to the expansion of the fluid transport pipe can be absorbed further immediately before the storage tank, and the influence can be avoided without giving the storage tank its effect. The accuracy can be further improved.

As a storage amount measuring device, a balance device is a spring type, a pendulum type,
Alternatively, it is possible to use a mechanical weighing device such as a weighing platform that is of a feeding weight type, but if the storage amount measuring device is a load cell or a balance using a load cell, accurate and easy control can be performed. That is, the load cell has a high metering accuracy, can accurately measure the amount required for the post-process reactor, and can ensure good reactivity, and also can supply the required amount from the tank to the post-process reactor. In doing so, the opening / closing operation of the liquid withdrawal valve from the tank can be electrically and automatically performed.

Further, in the expansion joint of the present invention, the hot corrosive fluid is discharged from the outlet end through the passage pipe located in the central portion, and the outlet end of this passage pipe is located at a position protruding from the bellows and the outlet side joint. This prevents the hot corrosive fluid and its mist from coming into direct contact with the bellows and joints as much as possible, improving the corrosion resistance of the bellows and joints, and changing the material of this part from expensive nickel material to inexpensive material such as stainless steel material. It becomes possible to do.

〔Example〕

Next, the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the evaporator of the present invention.
In FIG. 1, the same or corresponding parts as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, a discharge pipe 2b for discharging high temperature and high concentration caustic soda having a temperature of 320 ° C. and a concentration of 95% produced in the evaporator 1 is attached to the lower part of the evaporator main body 2 of the evaporator 1, A caustic soda storage tank 5 is installed in the discharge pipe 2b via a transportation pipe 4. An expansion joint 7 as shown in detail in FIG. 2 is attached to the attachment portion of the transport pipe 4 which is the fluid intake portion of the storage tank 5. A steady rest member is provided on the fluid transport pipe 4 above the mounting position of the expansion joint 7.
4b is installed. Further, a load cell 11 as a weighing device is attached to a foundation 12 via a support 10 at the lower part of the storage tank 5, and the load cells 11 are provided at four places so as to receive the load evenly in a plan view. . A part of the vapor sent together with the concentrated liquid from the transport pipe 4 to the storage tank 5 escapes to smoothly store the concentrated liquid in the tank 5.
The pressure equalizing pipe 9 for receiving the inside is the vapor discharge pipe of the evaporator 1
It is provided so as to communicate with 2a, and a fluid withdrawing pipe 8 equipped with an electrically operated on-off valve 8a is connected to the lower part. The expansion joint 7 is also attached to the attachment portion of the tank 5 of the pressure equalizing pipe 9 or the fluid discharge pipe 8.

Next, the expansion joint of the present invention will be described.

First, the expansion joint in the process of reaching the present invention will be described with reference to FIG. In FIG. 5, the expansion joint 15 is a fluid inlet side joint (flange) 16 and a fluid outlet side joint (flange).
The bellows 18 and the bellows 18 are connected to each other in an expandable and contractible manner, and one end of a sleeve pipe 19 as a fluid guide passage is attached to a straight pipe portion of the bellows 18 on the inlet side joint 16 side. A fluid outlet end of the other end of the sleeve pipe 19 is located inside the bellows 18 with respect to the fluid outlet side joint 17. The wall thickness of the sleeve tube 19 is also the same as that of the bellows 18. In the expansion joint of this configuration, the high temperature corrosive fluid flows into the sleeve pipe 19 on the inlet side joint 16 side and is discharged to the outlet end, but the concentrated liquid accompanied with a part of the steam exhibits a bumping behavior as it is discharged. , The liquid or its mist scatters at the outlet end of the sleeve pipe 19 and enters the space between the bellows 18 and the sleeve pipe 19 to corrode the inner surface of the bellows 18 and the outer surface of the sleeve pipe 19 as well, resulting in extremely poor corrosion resistance. . For this reason, not only the sleeve tube 19 but also the bellows 18 must be made of a highly corrosion-resistant nickel (Ni) material, and the wall thickness of these must be increased, which is extremely expensive.

In view of such problems, the expansion joint of the present invention has been devised, and this embodiment will be described with reference to FIG.

In FIG. 2, in the expansion joint 7, the fluid inlet side joint (flange) 20 and the fluid outlet side joint (flange) 21 are expandably connected by a bellows-like bellows 22 to be integrated, and a central portion thereof is provided. Passage pipe through which hot caustic soda solution passes
The flange 23a formed on the upper end of the 23 is attached to the fluid inlet side joint 20. The passage pipe 23
Is a lap joint type tube. Further, the lower end 23c of the passage pipe 23 is provided so as to be positioned below and protruding from the fluid outlet side joint 21, and the fluid outlet side joint 21 has a gap between its inner diameter end and the outer diameter of the passage pipe 23. Has been held. That is, the fluid outlet side joint 21 is attached to the passage pipe 23 in a loosely fitted state. The inner diameter end side 21a of the fluid outlet side joint 21 is moved to the outer diameter side of the passage pipe 23 as much as possible, leaving a gap in which the expansion joint 7 can also absorb the movement in the radial direction as shown by the chain line. If it is formed in this way, it is more effective for preventing the invasion of the liquid and its mist. further,
On the outer surface of the passage pipe 23 inside the inner diameter end side 21a, the bending amount (compression amount) of the expansion joint 7 in the axial direction is taken into consideration in the axial direction with the inner diameter end side 21a in a bent state, as shown by the chain line. When the flange 23d is installed at a position where the
The labyrinth effect is further imparted by the flange 23d and the flange 23d, and it is even more effective for preventing the liquid and its mist from entering at the exit end of the passage pipe 23 which scatters freely. In addition, the fluid inlet side joint 2 of the flange 23a of the passage pipe 23
The method of attaching to 0 may be welding A, but both are simply joined together with a gasket interposed between them, and
As shown in the figure, when the expansion joint 7 is incorporated into a piping line, it may be tightened with a bolt nut 4d to fix the two. Furthermore, countersunk bolt holes B are formed in the flange 23a at appropriate intervals in the circumferential direction, and the fluid inlet side joint 20
A screw hole is drilled to connect the flange 23a and the fluid inlet side joint 20.
Insert a gasket between the inlet side fitting 20 and flange 23a
And the passage pipe 23 may be attached by fixing them with countersunk bolts. Thus, if the flange 23a of the passage pipe 23 and the fluid inlet side joint 20 are detachably attached, it is easy to assemble the passage pipe 23 having the flange 23d as an expansion joint, and the passage pipe 23 Even if it corrodes, disassembly and assembly work such as removal and installation can be easily performed. As described above, in the expansion joint 7, only the passage tube 23 is in direct contact with the hot corrosive caustic soda.
Therefore, at least only the passage tube 23 may be made of the corrosion-resistant nickel (Ni) material, and the bellows 22 of other members,
The inlet side joint 20 and the like can be made of inexpensive stainless steel.

FIG. 3 is a vertical cross-sectional view showing the mounting procedure of the expansion joint 7.

In FIG. 3, an expansion joint 7 is attached to the fluid inlet 5c of the storage tank 5 via a general gasket 5e in the joint 5d by fastening the outlet side joint 21 with a bolt nut 5f. Further, the expansion joint 7 has a fluid transport pipe 23 at its inlet side joint 20 and its pipe end joint.
4a are connected by interposing a corrosion resistant gasket 4b and tightening with a bolt nut 4d. In this case, the corrosion resistant gasket 4b is attached between the flange 3a of the passage pipe 23 and the transport pipe end surface flange 4c joined to the surface of the joint 4a of the fluid transport pipe 4, and the joint 4a and the inlet side joint 20 of the expansion joint 7 are attached. By tightening and with bolts and nuts 4d, they are compressed and liquid leakage is sealed. Note that the end portion of the pipe 4 having the transport pipe end surface flange 4c is the passage pipe 23 of the expansion joint 7.
It is considered to be a lap joint type tube similar to.

Next, the operation of the embodiment of the present invention constructed as above will be described.

The 320 ° C., 95% caustic soda solution produced in the evaporator 1 flows into the fluid transport pipe 4 from the discharge pipe 2b of the evaporator main body 2, and the pipe 4 is attached to the storage tank 5 of the pipe 4. Entrance 5c
It is received in the storage tank 5 through the passage pipe 23 of the expansion joint 7 installed in the section. The fluid transport pipe 4 has, for example, a diameter of 2 to
It has a specified length of 2.5 inches and is heated to a high temperature by caustic soda at a high temperature of 320 ° C passing through it, and it expands due to thermal expansion in the longitudinal direction. This expansion is caused by bending the bellows 22 of the expansion joint 7. Be absorbed. The outlet end 23c of the passage pipe 23 of the expansion joint 7 is located below the joint 21d on the outlet side of the expansion joint 7 and the joint 5d of the inlet 5c of the storage tank 5 so that it is located below the high temperature corrosive caustic soda. Mist bellows 22
Direct contact with the fittings 20 and 21 is avoided and the bellows
22 and the joints 20 and 21 have improved corrosion resistance. Also, expansion joint 7
The outlet side joint 21 is provided with an inner diameter end side 21a, or is provided with the inner side flange 23d of the passage pipe 23 to provide a labyrinth effect, so that the outlet of the passage pipe 23 is scattered. It is even more effective in preventing the intrusion of liquid and its mist at the edges.

A predetermined amount of caustic soda solution is stored in the storage tank 5, and four load cells 11 attached to the lower part
Thus, the storage solution amount is measured in a state where the weight of the tank 5 and the weight of the pipe are added. Then, it is confirmed by the indicated value of the load cell 11 that the amount required for the reactor of the next step has been stored, and based on this, the electrically operated on-off valve 8a is opened, and the caustic soda solution is fed from the fluid withdrawal pipe 8 to the reactor. Supply. In addition,
The tank 5 is used to calculate the weight value of the load cell 11.
Measure the load value in the empty state as the zero point (reference value). The temperature of the fluid transport pipe 4 and the fluid withdrawal pipe 8 is 32 during operation.
At 0 ° C., the tubes 4, 8 and the pressure equalizing tube 9 expand due to thermal expansion, but the load due to the expansion is absorbed by the bellows 22 of the expansion joint 7 at the mounting position of the tubes 4, 8, 9 on the tank 5. Therefore, the weighing accuracy by the load cell 11 is extremely excellently ensured. The expansion joint 7 can be attached, for example, in the middle of the pipe 4 or to the discharge pipe 2b of the evaporation pipe 1 so as to absorb the expansion. In this case, between the attachment position of the expansion joint and the storage tank 5. The expansion of the pipe 4 of the tank 5
The expansion joint 7 is a storage tank
It is most effective to provide it at the mounting portion of the pipe 4. Of course,
It is still more effective if it is attached to the storage tank 5 and to another portion, for example, the discharge pipe 2b of the evaporator 1. The same applies to the tubes 8 and 9. Of these pipes 4, 8 and 9, since the fluid transport pipe 4 becomes an intermittent and unsteady flow of the liquid mixed with vapor, the expansion and contraction frequency of the fluid transport pipe 4 becomes the highest, so at least this fluid Transport pipe 4
It is necessary to attach the expansion joint 7 to. Load cell 11
By measuring with, the measurement error of the load cell 11 itself is about ± 0.05%, but even when including the opening / closing time of the electric opening / closing valve 8a, the measurement error can be secured to about ± 1%.
The amount of solution required for the reactor in the subsequent step is accurately measured, and the reaction can be efficiently performed in the reactor.

[Effect of device]

As is clear from the above description, in the evaporation device of the present invention, the flow rate or the amount of the high-temperature corrosive fluid can be accurately measured in the liquid state as it is. Further, since the expansion joint is attached to the fluid transportation pipe connected to the tank and flowing the high temperature corrosive fluid, the thermal stress due to the expansion of the fluid transportation pipe due to the high temperature is absorbed by the expansion joint and the influence on the tank is exerted. The amount is reduced and weighing is performed accurately.

When the expansion joint is installed in the fluid transport pipe mounting portion of the storage tank, the thermal stress due to the expansion of the fluid transport pipe can be absorbed further immediately before the storage tank, and the influence can be avoided without giving the storage tank its effect. The accuracy can be further improved.

When the storage amount measuring device is a load cell, the weighing is accurate and easy to control. That is, the load cell has a high metering accuracy, for example, it is possible to accurately measure the amount required for the reactor in the subsequent process, and to ensure good reactivity, and to send the required amount from the tank to the reactor in the subsequent process. When supplying the fluid, the opening / closing operation of the fluid withdrawal valve from the tank can be automatically performed automatically.

Further, in the expansion joint of the present invention, the hot corrosive fluid is discharged from the outlet end through the passage pipe located in the central portion, and the outlet end of this passage pipe is located at a position protruding from the bellows and the outlet side joint. This prevents the hot corrosive fluid and its mist from coming into direct contact with the bellows and joints as much as possible, improving the corrosion resistance of the bellows and joints, and changing the material of this part from expensive nickel material to inexpensive material such as stainless steel material. It becomes possible to do.

[Brief description of drawings]

FIG. 1 is a system diagram (partial longitudinal sectional view) showing an embodiment of an evaporator of the present invention, FIG. 2 is a longitudinal sectional view showing an expansion joint according to the present invention, and FIG. 3 is an expansion joint of the present invention. FIG. 4 is an enlarged vertical sectional view showing details of the attached state, FIG. 4 is a system diagram showing a conventional evaporator, and FIG. 5 is a vertical sectional view showing an expansion joint in the process leading to the present invention. 1 ... Evaporator, 2 ... Evaporator body, 3 ... Heat exchanger, 4
…… Fluid transport pipe, 5 …… Storage tank, 9 …… Pressure equalizing pipe, 11
…… Load cell, 7 …… Expansion joint, 20 …… Inlet side joint,
21 …… Outlet side joint, 22 …… Bellows, 23 …… Passage pipe, 23
c …… Outlet end, 21a …… Inner diameter end side, 23d …… Flange.

Claims (4)

[Scope of utility model registration request] 1. An evaporator for producing a high temperature corrosive fluid and a storage tank for receiving the fluid are connected by a fluid transportation pipe having an expansion joint, and a storage amount measuring device is attached to the storage tank. Evaporator for high temperature corrosive fluids. 2. A high-temperature corrosive fluid evaporator according to claim 1, wherein the expansion joint is installed in a fluid-transport-pipe mounting portion of a storage tank. 3. The evaporation device for hot corrosive fluid according to claim 1, wherein the storage amount measuring device is a load cell. 4. A passage pipe for hot corrosive fluid is located at the center, a joint is attached to the inlet side of one end of the passage pipe, and the other joint is loosely fitted to the passage pipe at the outlet side of the other end. And a bellows is mounted between the inlet side joint and the outlet side joint so as to surround the passage pipe, and the outlet end of the passage pipe is provided at a position protruding from the outlet side joint. Expansion joint used for evaporation device of high temperature corrosive fluid.