JP3936890B2 - Fluid reaction tower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bleaching tower or other fluid reaction tower used for bleaching pulp.
[0002]
[Prior art]
For example, a bleaching reaction tower conventionally used as a bleaching tower for pulp has a mortar finish layer formed inside an outer cylinder mainly composed of a reinforced concrete cylinder, and a lining such as FRP or rubber is provided on the inner side. The inner surface is lined with porcelain bricks. FIG. 6 shows a cross section of a peripheral wall portion of a conventional bleaching tower. This bleaching tower 100 is provided with a heat insulating material layer 101 on the outermost side and a reinforced concrete layer 102 on the inner side thereof. The inner surface of this reinforced concrete layer is a mortar finish layer 103 as shown in FIG. 7, and a lining layer 104 such as rubber is provided on the inner side, and a corrosion-resistant lining layer 105 for porcelain tiles is further provided on the inner side. Yes. FIG. 8 shows a state of the conventional bleaching tower 100 as viewed from above.
[0003]
In the pulp bleaching process using the conventional bleaching tower, chlorine has been used as a bleaching agent. In recent years, however, the use of chlorine, which has been used as a bleaching agent, has been banned for pollution prevention. Instead, highly corrosive chlorine dioxide or the like must be used, and bleaching must be performed at a liquid temperature of 70 ° C or higher. Since it has become necessary, the internal material of the bleaching tower needs to be changed. That is, the conventional reaction tower using chlorine as a bleaching agent was sufficiently used by providing a porcelain tile lining on the inner surface. However, when chlorine dioxide is used, it is highly corrosive. There is a problem that porcelain tiles cannot be used in a short time. When the porcelain tile lining is corroded, it is necessary to stop the operation of the reaction tower, remove the old lining, and apply a new lining, but this repair work requires a lot of manpower and time. The outage time became longer and a huge loss occurred.
[0004]
[Problems to be solved by the invention]
In addition, in order to improve the corrosion resistance, an attempt was made to apply a lining by attaching a highly corrosion-resistant titanium strip to the inner surface of the reaction tower. However, since titanium materials cannot be welded to dissimilar materials, this lining is long. Time was required and the problem of loss due to long reactor downtime still occurred. Therefore, an object of the present invention is to improve the early corrosion of the inner surface of the conventional reaction tower, and to perform the repair easily and in a short time.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following configuration. That is, reactor fluid according to the present invention, the supply port of the fluid is provided at the lower end, the concrete structure of titanium or stainless or Ranaru inner tube opening is provided overflowing fluid to the upper end It is characterized by being fitted and held inside the outer cylinder made of.
[0006]
In this reaction tower, instead of lining the inner surface, an inner cylinder made of a highly corrosion-resistant metal material such as titanium or stainless steel is fitted into the outer cylinder. Use of time is possible. Further, when a repair is required due to corrosion, the corroded portion of the inner cylinder can be easily repaired by welding or the like. Furthermore, since the inner cylinder can be manufactured independently of the outer cylinder, the stop period of the reaction tower by the outer cylinder can be shortened as much as possible.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described. FIG. 1 shows a pulp bleaching tower as an example of the reaction tower of the present invention. The bleaching tower 1 is formed by fitting an inner cylinder 3 into an outer cylinder 2. The outer cylinder 2 is formed as a cylinder in which a reinforced concrete layer 7 is provided inside an exterior material 5, and the inner surface of the reinforced concrete layer 7 is a mortar finish layer 8. A lining layer 9 such as rubber or FRP is provided on the surface of the mortar layer 8. In the case of a conventional bleaching tower, as described above, a lining layer such as a porcelain tile is provided on the surface of the lining layer. However, in the embodiment of the present invention, such a porcelain tile lining is not provided. .
[0008]
A base 10 is integrally provided at the lower end of the outer cylinder 2. The outer diameter of the base 10 is substantially the same as that of the outer cylinder 2 and has a split hollow structure as shown in FIG. 3 so that the lower end of the outer cylinder 2 is supported by being lifted by about 2 m. Inside the base 10, a supply pipe P1 for supplying slurry-like pulp is disposed.
[0009]
Note that the inner surface 12 of the lower end portion forming the bottom of the outer cylinder 2 has a spherical shape or a tapered shape, and an opening portion 13 is provided at the center thereof. A metal ring member 14 for reinforcement is provided on the inner peripheral portion of the opening 13, and when the mortar 16 is filled as will be described later, the metal ring member 14 is closed so that the mortar 16 does not leak. It has become.
[0010]
Next, the inner cylinder 3 has a cylindrical shape integrally made of titanium or stainless steel, particularly super stainless steel (JIS standard M6) having high corrosion resistance. As a titanium material, an appropriate titanium alloy can be used in addition to pure titanium. In short, any titanium or stainless steel material excellent in corrosion resistance may be used. The inner cylinder 3 is made of titanium or stainless steel plates joined together by welding, and is manufactured independently of the outer cylinder 2 and has the following structure. The plate thickness is slightly different depending on each part of the inner cylinder 3, and the thinnest part is 4.0 mm, and the thickest part is 12.0 mm. The parts that are susceptible to corrosion and the parts where a large force acts are thick.
[0011]
As shown in FIG. 4, the lower end portion 14 of the inner cylinder 3 is formed in a conical shape in which the tip end side is narrowed, and a supply port 15 is provided in the central portion of the lower end portion. A gap portion between the conical portion 14 and the inner surface of the outer cylinder 2 is filled with mortar 16 as shown in FIG. 1, thereby firmly supporting the inner cylinder 3. In FIG. 1, reference numeral 17 denotes a filling port for the mortar, which is provided at two locations along the circumference of the outer cylinder. Reference numeral 18 denotes a drain hole, which is also provided at two locations. A gap s of several mm to several tens of mm is provided between the outer peripheral surface of the inner cylinder 3 and the inner peripheral surface of the outer cylinder 2. For this reason, it is easy to fit the inner cylinder 3 into the outer cylinder 2, and even if there are irregularities on the inner surface of the outer cylinder, the inner cylinder 3 can be easily fitted. Even if the inner cylinder 3 is slightly thermally expanded, there is no problem.
[0012]
As shown in FIG. 1, the upper portion of the inner cylinder 3 protrudes upward by a length L from the upper end of the outer cylinder 2, and the inner cylinder 3 protrudes upward by a length L in the outer cylinder 2. This is to compensate for the volume reduction due to the provision of the inner cylinder 3 by increasing the height of the inner cylinder 3 by the length L. The outer diameter of the inner cylinder 3 is formed with a considerable margin in the inner diameter of the outer cylinder 2. This is to facilitate the fitting operation of the inner cylinder 3 to the outer cylinder 2. Thus, when the inner cylinder 3 is fitted to the outer cylinder 2 with a margin, a considerable gap s is formed between them as described above. Therefore, after the inner cylinder 3 is fitted to the outer cylinder 2, a plurality of (eight in the illustrated example) anti-sway members 20,... Project outwardly are welded and fixed to the base of the protruding portion of the inner cylinder 3. ing. As shown in FIG. 5, the anti-sway member 20 includes a lateral portion 20 a that is placed on the upper end surface of the outer cylinder 2, and a vertical portion 20 b that abuts against the inner surface of the outer cylinder 2. When the inner cylinder 3 is thermally expanded in the axial direction, the vertical direction 20 b slides along the inner surface of the outer cylinder 2.
[0013]
The upper end of the inner cylinder 3 is an opening 22 as shown in FIG. In addition, a tray portion 23 that receives pulp overflowing from the opening portion 22 is integrally provided on the upper portion of the inner cylinder 3. As shown in FIGS. 1 and 2, the tray portion 23 is formed as a ring-shaped groove-like recess having a peripheral wall 23a provided along the outer periphery of the main body of the inner cylinder 3 and a bottom surface 23b inclined to one side. A discharge port 24 is provided at the lowest bottom surface. The saucer portion 23 is not a perfect circle in plan view, and its radius is the largest at the portion where the discharge port 24 is provided, and gradually decreases toward the higher portion on the opposite side. A discharge nozzle 25 is attached to the discharge port 24, and a discharge pipe P2 is connected to the discharge nozzle.
[0014]
As shown in FIG. 1, the upper side of the tray portion 23 of the inner cylinder 3 is covered with a cap 27. A rotating shaft 30 is inserted through the center of the cap 27, and a stirring tool 32 is attached to the rotating shaft. The stirring tool 32 is provided with a plurality of stirring blades 32b,... Below a plurality of radially provided arms 32a,... It is like that. An electric motor 35 and a speed reducer 36 are provided on the top of the rotating shaft 30.
[0015]
When bleaching pulp using this bleaching tower 1, raw material pulp is supplied into the inner cylinder 3 from a supply pipe P <b> 1 connected to a supply port 15 provided below the bleaching tower 1. The pulp is in the form of a slurry, and chlorine dioxide as a bleaching agent is added in the middle of the supply pipe. The pulp gradually rises in the inner cylinder 3 and is bleached in the meantime, and overflows from the opening 22 at the upper end. At this time, the pulp is stirred and scraped by the rotating stirring tool 32. The pulp flowing out from the opening 22 is received in the tray 23, flows to the discharge port 24 side along the inclined bottom surface 23b of the tray, and passes from the discharge nozzle 25 to the predetermined place through the discharge pipe P2. Sent.
[0016]
The bleaching tower 1 is made of a titanium or stainless steel material having excellent corrosion resistance, and the inner cylinder 3 where the raw material and the bleaching agent are in contact with each other. Therefore, the bleaching tower 1 is less likely to be corroded than a conventional bleaching tower lined with porcelain tiles. You can continue driving for hours.
[0017]
The feature of the present invention is that the inner cylinder 3 having the above structure can be manufactured independently of the existing outer cylinder 2.
[0018]
That is, in order to repair the existing outer cylinder 2 used as a bleaching reaction tower, it is natural that the operation of the outer cylinder 2 must be stopped for the modification. In the conventional method of directly relining the inner wall of the outer cylinder 2 by lining the titanium material, the operation of the reaction tower must be stopped during that time, and the loss is enormous.
[0019]
In this respect, in the present invention, since the inner cylinder 3 can be manufactured separately and independently outside the outer cylinder 2, the operation by the outer cylinder 2 is performed for a short period of time when the manufacture of the inner cylinder 3 is completed. Since the repair work is completed simply by fitting the inner cylinder 3 to the outer cylinder 2 and performing the auxiliary work, the repair period of the outer cylinder 2, that is, the reaction tower, can be greatly shortened. Enormous losses due to tower shutdowns can be greatly reduced.
[0020]
【The invention's effect】
As apparent from the above description, the reaction tower according to the present invention, since the reaction column by the inner tube which is easily corroded formed integrally of titanium or stainless, fitting it into the barrel, It became excellent as a reaction tower that required corrosion resistance, such as bleaching of pulp.
[0021]
In particular, since it is possible to manufacture the inner cylinder separately and independently outside the outer cylinder, when the production of the inner cylinder is completed, the operation by the outer cylinder is stopped for a short period of time. Since the repair work is completed simply by fitting the two and performing the auxiliary work, the repair period of the outer cylinder, that is, the reaction tower, can be greatly shortened, and the enormous loss due to the shutdown of the reaction tower is greatly reduced. be able to.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view illustrating an embodiment of the present invention.
FIG. 2 is a view taken along arrow XX in FIG.
FIG. 3 is a view on arrow YY in FIG. 1;
FIG. 4 is a partially sectional front view of an inner cylinder.
FIG. 5 is a front view of an anti-sway member.
FIG. 6 is a longitudinal sectional view of a conventional bleaching tower.
FIG. 7 is an enlarged cross-sectional view of the main part.
FIG. 8 is a plan view thereof.
[Explanation of symbols]
1 Bleach tower (reaction tower)
2 Outer cylinder 3 Inner cylinder 7 Reinforced concrete layer 10 Base 15 Supply port 20 Anti-sway member 22 Opening 23 Sauce pan 32 Stirring tool

Claims (5)

Supply port of the fluid is provided at the lower end, the upper end and fitted and held titanium or stainless or Ranaru inner tube opening is provided overflowing fluid inside the outer cylinder made of a concrete structure A fluid reaction tower. The reaction tower according to claim 1, wherein a receiving tray portion that receives fluid overflowing from the opening is provided at an upper portion of the inner cylinder, and a fluid discharge port is provided in the receiving tray portion.   The reaction tower according to claim 1 or 2, wherein a lower end of the inner cylinder is formed in a conical shape with a thin tip, and a fluid supply port is provided at a lower end thereof.   The reaction tower according to any one of claims 1 to 3, wherein mortar is filled between an inner surface of a lower end portion of the outer cylinder and an outer peripheral surface of the inner cylinder.   The upper end portion of the inner cylinder protrudes from the outer cylinder, and an anti-sway member that abuts against the outer cylinder and restricts the oscillation of the inner cylinder protrudes from the base of the protruding portion. A fluid reaction tower as described in 1. above.

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