JPH0735245B2 - Continuous production equipment for highly concentrated sodium hypochlorite aqueous solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention [Field of Industrial Application] The present invention relates to an apparatus for continuously producing a high-concentration sodium hypochlorite aqueous solution.

[Conventional technology]

A high-concentration aqueous solution of sodium hypochlorite (NaOCl), which is useful as an oxidizing agent, bleaching agent, disinfectant, etc. (hereinafter abbreviated as "hypo-sub-liquid") is industrially used as a high-concentration caustic (caustic) soda aqueous solution with chlorine gas. Blow in to cause a chlorination reaction of 2NaOH + Cl ₂ → NaOCl + NaCl ↓ + H ₂ O.

By-produced salt (NaCl) will precipitate when the saturated amount in the liquid phase of the reaction system is exceeded. After sufficient reaction, the reaction solution containing the precipitated salt crystal component in the reaction vessel is subjected to solid-liquid separation operation to obtain a highly concentrated hyposublimate in which the salt crystal component is substantially removed. The produced high-concentration hypothionite is used as it is, or adjusted to an appropriate concentration, or crystallized as a crystal (NaOCl.5H ₂ O) to obtain a product.

[Problems to be solved by the invention]

(1) The conventional method for producing hypochlorous liquid is a batch method, and what is called a continuous method is also a variation of the batch method. In practice, the continuous method has the inherent advantages in terms of consistency of product quality. It does not have enough.

(2) In order to carry out the chlorination reaction smoothly and swiftly, it is necessary to uniformly mix chlorine gas in each part of the high-concentration caustic soda aqueous solution as a raw material. Therefore, conventionally, a power stirring device such as a stirring blade or a stirring screw is provided in the reaction tank to stir and mix both of them as much as possible.

However, since a large amount of by-product salt crystal slurry is present in the reaction tank, the presence of the large amount of slurry itself hinders the smooth and rapid progress of the chlorination reaction, and
The stirring resistance is large, so that the energy consumption of the power stirring device is large, and it is difficult to obtain a sufficient stirring and fluidized state of the entire raw material liquid in the reaction tank, and the chlorination reaction of the raw material liquid in the reaction tank is actually localized. It is easy to make uneven. Heterogeneity of the reaction leads to inhomogeneous product quality. If the power stirring device is made stronger, the size of the entire device will increase and the energy consumption will increase.

(3) The inner wall surface of the reaction vessel and the stirring member are liable to be mechanically worn or damaged by stirring and flowing of the raw material liquid containing a large amount of the by-product salt crystal slurry, and the durability is lowered. Further, the salt crystal slurry adhered and grew as a scale on the inner wall surface of the reaction tank and the stirring member, and the scale had to be removed regularly or quite frequently as needed.

The present invention has been proposed in view of the above, and does not have the above problems. It is an object of the present invention to provide a reasonable continuous production apparatus for high concentration hypothionite.

B. Structure of the Invention [Means for Solving the Problems] The present invention is summarized by an apparatus for continuously producing a high-concentration sodium hypochlorite aqueous solution, which is characterized by the following structures A to E.

A, an inlet pipe for a high-concentration caustic soda aqueous solution and a jet inlet pipe for a circulating reaction liquid are provided on the upper side of the tank, and a chlorine gas blowing nozzle that opens to a substantially central portion in the tank at the lower part of the tank is provided. A vertical reaction tank comprising a reaction solution take-out pipe on the lower side of the tank, wherein the circulating reaction solution jet inlet pipe is arranged with its tube axis substantially tangential to the inner wall surface of the tank; The reaction solution take-out pipe of the vertical reaction tank has a height position that is substantially the same as or lower than that of the reaction liquid take-out pipe, and the pipe axis is arranged substantially tangential to the inner wall surface of the tank so as to communicate with the reaction liquid take-out pipe. A cyclone comprising a reaction liquid jet inlet pipe, and a reaction liquid collecting pipe for collecting a part of the reaction liquid in the tank in which the salt crystal content is substantially separated by the centrifugal separation action in the tank, C, a reaction liquid containing substantially no salt crystal fraction collected from the cyclone reaction liquid collecting pipe A pump device for continuously collecting from the preparative pipe and forcing it to the circulating reaction liquid jet inlet pipe of the vertical reaction tank; and D, a circulation reaction of the vertical reaction tank from the reaction liquid collecting pipe of the cyclone. A reaction solution cooler interposed in a reaction solution feed path including the pump device to the liquid jet inlet tube; and E, a reaction solution containing a salt crystal component continuously flowing out from a lower outlet tube of the cyclone, Solid-liquid separator for separating sodium hypochlorite aqueous solution and salt crystals.

[Operation] That is, the high-concentration caustic soda aqueous solution, which is a raw material liquid, is continuously introduced into the vertical reaction tank from the high-concentration caustic soda aqueous solution inlet pipe on the upper side of the tank at a predetermined supply rate per unit time.

Similarly, a circulating reaction solution jet inlet pipe on the upper side of the tank is provided with a reaction liquid which is dispensed from the cyclone side by a reaction liquid collecting pipe and a pump device and which is pumped to the inlet pipe and substantially free of a salt crystal component. Is continuously introduced as a jet flow with the supply amount per unit time.

Since the circulating reaction solution jet inlet pipe is arranged with its tube axis substantially tangential to the inner wall surface of the reaction tank, the introduced circulating reaction liquid flows from the inlet pipe into the reaction tank and the inner wall of the reaction tank. It flows in as a swirling jet along.

As a result, the entire liquid in the reaction tank effectively becomes a swirling turbulent flow and becomes a fluidized state.

On the other hand, in the vertical reaction tank, chlorine gas is continuously blown into the reaction tank at a predetermined supply amount per unit time from a chlorine gas injection nozzle that opens at approximately the center of the reaction tank at the bottom of the reaction tank. The chlorination reaction of the raw material liquid is carried out by mixing with the raw material liquid inside.

The reaction liquid continuously flows out of the reaction tank from the outlet pipe on the lower side of the reaction tank by the water head pressure in the reaction tank. The amount of liquid in the reaction tank can be kept at a predetermined substantially constant amount by adjusting the amount of introduced liquid (high-concentration caustic soda solution + circulation reaction liquid) and the amount of effluent to be substantially equal.

Thus, the liquid in the reaction tank continuously flows out from the outlet pipe on the lower side of the tank, and descends while swirling from the upper side to the lower side in the tank. On the other hand, in the chlorine gas blown into the reaction tank from the lower side of the tank, its bubbles rise in a countercurrent state to the swirling down flowing liquid, and are vigorously entrained in the swirling down flowing liquid during the rising process. Each part is uniformly and finely dispersed and mixed in the entire liquid in the reaction tank. As a result, the raw material liquid in the reaction tank is uniformly chlorinated at each part.

The by-product salt crystals, which are solid particles that are precipitated by the chlorination reaction, are spun from the depositing edge to the inner wall of the reaction tank by the swirling centrifugal force of the swirling downward fluid, descending along the inner wall of the reaction tank, and the lower part of the reaction tank. And the reaction liquid continuously flowing out of the outlet pipe of the above. As a result, the inside of the reaction vessel is always kept in a state in which a large amount of by-product salt crystal slurry does not exist.

As a result, since the apparent specific gravity of the liquid in the reaction tank does not increase due to the presence of a large amount of by-produced salt crystals, the circulating reaction liquid jet introduced into the reaction tank has a relatively small flow energy to allow the reaction liquid to flow into the reaction tank. The entire liquid in the form of a swirling turbulent flow effectively and downwardly flows downward in the reaction tank, while the blown chlorine gas that rises countercurrently is uniformly mixed in each part, and a large amount of by-product salt crystals Since the progress of the chlorination reaction is not hindered by the presence of the slurry, a smooth and rapid uniform chlorination reaction in each part is continuously executed in the reaction tank.

As described above, the by-produced salt crystal component produced in the reaction vessel continuously flows out of the reaction vessel together with the reaction solution continuously flowing out of the outlet pipe on the lower side of the reaction vessel to produce a large amount of salt crystal slurry. Since the slurry does not adhere to and grows on the inner wall surface of the reaction vessel as a scale, it does not substantially occur, and even if it occurs, it is extremely slow, and the need for frequent scale removal in the reaction vessel is eliminated.

Since the absolute amount of salt crystals as solid particles that are always present in the reaction tank is small, the mechanical wear and damage on the inner wall surface of the reaction tank due to the conventional flow of salt crystal slurry is significantly reduced. .

It continuously flows out from the reaction solution outlet pipe on the lower side of the reaction tank,
The reaction liquid containing the by-produced salt crystal component is continuously introduced into the cyclone through the reaction liquid jet inlet pipe of the cyclone.

In this case, since the reaction liquid jet inlet pipe of the cyclone is located at the same height position as or lower than the reaction liquid outlet pipe of the reaction tank, the reaction liquid flows from the inlet pipe into the cyclone at a high head pressure in the reaction tank. It becomes a jet and is continuously introduced. Since the reaction solution jet inlet pipe is arranged with the pipe axis line substantially tangential to the inner wall surface of the cyclone tank, the introduced reaction liquid is swirled into the cyclone from the inlet pipe along the inner wall of the cyclone. Flows in as.

Thus, the salt crystal component in the reaction solution that has flowed into the cyclone as a swirl flow is centrifugally separated toward the cyclone inner wall side, descends along the cyclone inner wall, and together with the reaction solution that continuously flows out from the outlet pipe at the bottom of the cyclone. It continuously goes out of the cyclone.

The reaction liquid in the cyclone continuously flows out from the outlet pipe at the lower part of the cyclone as described above, while the salt crystals are centrifugally separated on the inner wall of the cyclone and a part of the reaction liquid portion substantially not containing the salt crystal components is generated. The cyclone is taken out of the cyclone by a preparative pipe and a pump device, and is continuously pumped as the circulating reaction liquid to the circulating reaction liquid jet inlet pipe of the reaction tank.

In this case, the circulating reaction liquid is exposed to the heat of reaction held in the reaction tank by the cooler interposed in the passage from the cyclone reaction liquid collecting pipe to the circulating reaction liquid jet inlet pipe of the reaction tank, and is heated to about room temperature. It is cooled and circulated into the reaction tank.

The amount of liquid in the cyclone is the amount of liquid introduced from the reaction tank side and the amount of effluent (amount of outflow from the lower outlet pipe + amount of aliquot from the preparative pipe)
Are adjusted to be substantially equal to each other so that they are always maintained at a predetermined substantially constant amount.

The reaction liquid containing salt crystals, which continuously flows out from the lower outlet pipe of the cyclone, is subjected to solid-liquid separation operation in the solid-liquid separator into the high-concentration hyposub-liquid and the by-product salt crystal component, in this way. The high-concentration hypothalite solution obtained continuously has substantially no quality fluctuation with time and unevenness.

Thus, the intended high-concentration secondary sub-liquid continuous production apparatus is constructed, which is compact and energy-saving, and which is fully equipped with the features of a continuous production apparatus.

〔Example〕

The drawings show the apparatus of one embodiment, FIG. 1 is a systematic diagram of the entire apparatus, FIG. 2 is a partially cutaway plan view of a reaction tank, and FIG. 3 is a partially cutaway plan view of a cyclone.

Reference numeral 1 is a vertical cylindrical reaction tank, 11 is a high-concentration caustic soda aqueous solution inlet pipe disposed on the upper side of the tank, and the high-concentration caustic soda aqueous solution a fed from a reservoir (not shown) is the inlet pipe.
11 is continuously introduced into the reaction tank 1 at a predetermined supply amount per unit time.

Reference numeral 12 is a circulating reaction solution jet inlet pipe similarly arranged on the upper side of the tank 1, and its pipe axis is arranged substantially tangential to the inner wall surface of the tank 1 as shown in FIG. This inlet pipe 12
In the cyclone 2 to be described later in the reaction tank 1, a portion of the reaction solution in which the salt crystal component is centrifugally separated and does not substantially contain the salt crystal component is a circulating reaction liquid c2 in a jet state for a predetermined unit time. Introduced at a per supply rate.

Reference numeral 13 denotes a chlorine gas blowing nozzle opened at a substantially central portion in the tank 1 in the lower portion of the tank 1. With this nozzle, chlorine gas b from a chlorine gas source (not shown) is supplied into the tank 1 for a predetermined unit time. The high-concentration caustic soda aqueous solution, which is the raw material liquid in the tank 1, is chlorinated by the supplied amount.

Although the chlorine gas blowing nozzle 13 of the illustrated embodiment is opened in the liquid phase, it may be opened in the gas phase.

Reference numeral 14 denotes a reaction solution take-out pipe arranged on the lower side of the tank 1, and in the case of this example, the take-out pipe 14 also has a pipe axis line of the tank 1 as shown in FIG. The reaction liquid c1 swirling and descending in the tank 1 is naturally allowed to flow naturally as it is by arranging it in a direction substantially tangential to the inner wall surface. 15
Is an upper cover plate of the tank 1, and 16 is a gas vent pipe provided at the center of the upper cover plate so as to penetrate the plate.

The above-described action and effect of the reaction tank 1 are as described in the above items of action.

2 is a cylindrical cyclone in which the lower half is roughly conical, 21
Is a reaction solution jet inlet pipe provided at a position higher than the inverted conical portion of the cyclone, and the pipe axis is provided substantially tangential to the inner wall surface of the cyclone tank as shown in FIG. 22 is a reaction liquid collection pipe provided at a position substantially the same height as the inlet pipe 21 with the reaction liquid collection port being located at a substantially center line position in the cyclone tank, and 23 is the lower end of the inverted cone of the cyclone 2. It is a reaction solution outlet pipe.

In the reaction tank 1 and the cyclone 2, the reaction liquid jet inlet pipe 21 on the cyclone 2 side is substantially the same as or lower than the position of the reaction liquid take-out pipe 14 on the reaction tank 1 side. The pipes 14 and 21 are connected to each other by a pipe 17 so that the pipes 14 and 21 are connected to each other.

The reaction liquid c1 swirling and descending in the reaction tank 1 and entering the take-out pipe 14 passes through the pipe 17 into the cyclone from the inlet pipe 21 of the cyclone 2 and becomes a swirling jet flow due to the high head pressure in the reaction tank. The salt crystal component introduced and supplied per unit time is centrifuged to the inner side of the cyclone. Cyclone 2
The reaction solution in the portion close to the cyclone center line in the inside is a solution containing substantially no salt crystal content because the contained salt crystal content is centrifuged toward the inner wall side of the cyclone. A part of the reaction liquid c2 that does not substantially contain a salt crystal component is continuously collected outside the cyclone 2 by the pump device 3 by the separation pipe 22.

The preparative reaction liquid c2 is pumped by the pump device 3 through the pipe 31 to the circulating reaction liquid jet inlet pipe 12 of the reaction tank 1 and introduced into the reaction tank 1 at a predetermined supply amount per unit time.

Reference numeral 4 denotes a cooler which is interposed in the middle of the pipe 31, and the circulating reaction liquid c2 is deprived of the reaction heat retained in the reaction tank 1 by the cooler and cooled to about room temperature and introduced into the reaction tank 1. It The cooler 4 may be arranged in the middle of the pipe between the reaction liquid collecting pipe 22 and the pump device 3.

Reference numeral 5 denotes a solid-liquid separator, which is a product containing a highly concentrated hypothalite c4 and a by-product salt crystal, into which a reaction liquid containing a salt crystal component, which continuously flows out from the reaction liquid outlet pipe 23 below the cyclone 2, is introduced. Minute
Solid-liquid separation into c5 and.

In addition, d represents a liquid flow rate adjusting valve provided at a required place in the piping system of the apparatus.

Thus, a highly concentrated hypothalite substantially free from quality fluctuations and nonuniformity over time is continuously produced. The main power source of the device system is the pump device 3 that circulates the reaction liquid c2, and the necessary stirring of the raw material liquid in the reaction tank 1 is effectively performed by the circulating reaction liquid jet c2 as described in the section of the above action. Since the necessary swirling of the reaction liquid in the cyclone 2 is effectively performed by the jet of the reaction liquid flowing into the cyclone by the head pressure in the reaction tank 1 as described in, the pump device 3 has a small size and a low output. One is enough, and the whole manufacturing equipment is downsized and energy saving.

C. Effect of the Invention As described above, according to the present invention, a small-sized, energy-saving type, highly durable, continuous production apparatus of a high-concentration sodium hypochlorite aqueous solution, which is sufficiently equipped with the features of the continuous method, is configured. The intended purpose is often achieved.

[Brief description of drawings]

The drawings show an apparatus according to an embodiment of the present invention. FIG. 1 is a systematic diagram of the entire apparatus, FIG. 2 is a partially cutaway plan view of a reaction tank, and FIG. 3 is a partially cutaway plan view of a cyclone. . 1 is a reaction tank, 2 is a cyclone, 3 is a pump device, 4 is a cooling device, and 5 is a solid-liquid separation device.

Claims (1)

[Claims] 1. A tank is provided with an inlet pipe (11) for a high-concentration caustic soda aqueous solution (a) and a jet inlet pipe (12) for a circulating reaction liquid (c2) at the upper side of the tank, and the inside of the tank A chlorine gas (b) injection nozzle (13) opening in the center is provided, and a reaction liquid (c1) take-out pipe (14) is provided on the lower side of the tank.
And a vertical reaction tank (1) in which the circulating reaction solution jet inlet pipe (12) is arranged with its tube axis substantially tangential to the inner wall surface of the tank, and the vertical reaction tank (1). ) Has a height position relationship substantially the same as or lower than that of the reaction liquid take-out pipe (14), and the reaction liquid take-out pipe (14) is arranged so that the pipe axis is substantially tangential to the inner wall surface of the tank.
The reaction solution jet inlet pipe (21) in communication with the reaction solution collection pipe for collecting a part of the reaction solution (c2) in the tank in which the salt crystals are substantially separated by the centrifugal action in the tank A cyclone (2) comprising: (22); and a reaction liquid (c2) substantially free of a salt crystal fraction separated from the reaction liquid collecting pipe (22) of the cyclone (2). A pump device (3) press-contacting the circulating reaction liquid jet inlet pipe (12) of the vertical reaction tank (1), and the vertical reaction tank (1) from the reaction liquid collecting pipe (22) of the cyclone (2). To the circulating reaction liquid jet inlet pipe (12) of
A reaction solution cooler (4) interposed in a reaction solution feed passage (31) including the pump device (3) and a salt crystal component continuously flowing out from the lower outlet pipe (23) of the cyclone (2). A high-concentration hypochlorous acid characterized by comprising a solid-liquid separator (5) for separating a reaction solution (c3) containing water into a high-concentration aqueous sodium hypochlorite solution (c4) and a salt crystal component (c5). Continuous production equipment for aqueous sodium chlorate solution.