KR840000792B1 - Apparatus for the preparation of slaked lime solution - Google Patents

Abstract

Slaked lime soln. is prepd. in a dissolution tank (1) with an agitator, where the lime is fluidized y water transported through the water inlet pipe (6) at a constant flow rate. The feed inlet (3) and weir (4) are located in the top section of 1, and the agitator and 6 are in the conically shaped bottom section of 1. The soln. is agitated by a turbine impeller, circulation pump, or water ejector. The bottom section with a inverse conical shape decreases the height of the fluidized particles so that contact of the slaked lime and water is more effective.

Description

Apparatus for Manufacturing Sour Lime Solution

1 is a schematic diagram showing an example of the apparatus of the present invention.

2 is a schematic view of an apparatus for agitating with a circulation pump.

3 is a schematic diagram of a device for agitating with a water ejector.

4 is a device for stirring with a stirring blade rotating in the vertical direction.

5 is a schematic diagram of continuous operation of two slaked lime dissolution tanks.

6 is a graph showing the change in concentration of the aqueous solution of slaked lime obtained by the apparatus of the present invention.

The present invention relates to an apparatus for continuously producing an aqueous solution of slaked lime.

Specifically, the apparatus is a device in which a slaked lime is added to a tank of which the lower part is in a back-vertical shape and water is continuously supplied from the bottom while stirring, and the aqueous solution of slaked lime is continuously taken out from the top of the tank.

The aqueous solution of slaked lime prepared by the present invention is used to adjust the pH of tap water to prevent rust of water pipes, and to supply calcium ions to drinking water obtained by desalination of sea water.

Water is a very soluble solvent and dissolves not only iron but also metals such as copper and aluminum.

Dissolution of metals by water results in the phenomenon of corrosion as the metal itself.

能力)을 격감시키는 동시에 용출된 철은 수산화 제2철로되어 공급수중에 함유되어 소위 녹물의 문제를 야기시킨다.Corrosion of water is a big problem for the water itself, where metal products such as steel pipes constitute the main part of the facility.

At the same time, the eluted iron becomes ferric hydroxide, which is contained in the feed water, causing a problem of so-called green matter.

Means that can be taken to control the drainage pipes in the water supply system include the control of tap water and the coating of steel pipes, etc., but there is a limit to the extent to be prevented by the coating. There are many things that cannot be completely covered.

Therefore, it is necessary to improve the water quality by adjusting the pH.

Alkaline agents used to adjust the pH of tap water include caustic soda, soda ash, and novel society.

Recently, caustic soda is used because of its ease of handling, but caustic soda is only used to adjust PH. When using slaked lime, it is preferable to use calcined lime because it has a function to prevent the corrosion of the pipe by making a coating of calcium carbonate on the pipe wall. It is also economical.

Nevertheless, the poor use of slaked lime does not melt well and requires a large tank to store it in solution, and it is not only difficult to continuously inject the powder, but also the dissolved residue is deposited on the bottom and adhered to the slurry. This is because there is a flaw that is easy to deposit in the middle of the pipeline.

In order to rectify the above-mentioned defects caused by the recent injection of slaked lime, a gold net is installed in the lower part of the tank and partitioned up and down, and a sediment layer is formed on the gold net and the water of the stable purified water tank separately installed from the lower side of the slaked lime solution tank filled with water is fixed. A method of feeding the saturated lime water from the top while feeding at a flow rate has been proposed.

According to this method, the retained slaked lime remains the same, and the tank may be very small compared to the solution and the storage, and since only the injection amount is melted, the dissolution tank is also reduced, and the apparatus is miniaturized as a whole. However, according to the research of the present inventors, in the above-described method, the aqueous solution of slaked lime having a concentration as expected can be taken out for the first several hours, but the concentration of slaked lime gradually decreases.

This is the reason that the hole becomes a passage of water in the stacked layer of slaked lime, and the hole becomes larger as time passes, and the water passes through the part without the deposited layer of slaked lime locally, so that the contact between water and slaked lime does not proceed well.

In addition, although the conventional method of forming a deposit of slaked lime on the gold mesh is used, even if it is not unconditional in the short time of several months, the hole of the gold mesh is blocked in the long-term continuous use for several years to close the water passage.

That is, the hole of the gold net is blocked by the trace amount of sand contained in the slaked lime or iron and other insoluble matter contained in the tap water.

In addition, free carbonic acid present in the water is converted to CaCo ₃ in the presence of Ca (OH) ₂ , so that the free carbonic acid becomes a scalding to block the hole of the gold mesh.

As a result of various studies by the inventors of the present invention, the present inventors have been able to stably obtain a saturated aqueous solution of slaked lime continuously for a long time without using a gold mesh inside the melting tank. The present invention has been reached.

According to the present invention, a slaked lime dissolution tank uses a tank having at least a lower portion of a reverse cone shape or a reverse cone shape (hereinafter referred to as a reverse cone shape), and a predetermined amount of slaked lime is introduced into the inside of the tank by installing a water inlet and a stirring means at the bottom of the tank. Then, the present invention relates to a device for continuously extracting a clear novel ash aqueous solution from the upper part of the bath by supplying water from the water supply port of the housewife while stirring and inducing slaked lime.

FIG. 1 is a schematic diagram showing an example of the apparatus of the present invention, and FIG. 2 and FIG. 4 are schematic diagrams of an apparatus provided with stirring means different from that of FIG.

That is, the stirring means of FIG. 1 is provided with a turbine type stirring blade, and FIG. 2 is agitating with a circulation pump, FIG. 3 is agitating with a water ejector, and FIG. 4 is agitating with agitating vanes rotating in a vertical direction. will be. 5 is a schematic diagram of the case where two slaked lime dissolution tanks are installed and continuously operated.

6 is a graph showing the change in concentration of the aqueous solution of slaked lime obtained by the apparatus of the present invention.

In the present invention, the slaked lime dissolution tank needs to make a difference in the cross-sectional area of the bottom and the upper portion, and therefore, at least the lower portion of the dissolution tank is used.

When water is supplied from the bottom, the flow velocity of water decreases toward the top with a wide cross-sectional area, and therefore the height of flowing of the slaked lime particles when stirring at the bottom with a small cross-sectional area can be suppressed relatively low. That is, since strong stirring force can be given as compared with the height of the flow of slaked lime particles, the contact between slaked lime and water can be efficiently performed, and thus, calcium carbonate produced by free carbonate in water or magnesium oxide present in slaked lime Magnesium hydroxide can cover the surface of the slaked lime particles to prevent the dissolution and it is possible to obtain an aqueous solution of slaked lime of approximately uniform concentration over a period of time until the undissolved slaked lime is almost eliminated.

In order to do so, the slaked lime dissolution tank needs to be a back type with a large cross-sectional area at the top with respect to the bottom, and at least the fluidized bed portion of the slaked lime particles due to agitation is preferably a back type with a width toward upward.

Although stirring is carried out from the beginning of operation, when the slaked lime used contains a large amount of microparticles which are easy to dissolve, an aqueous solution of slaked lime close to the saturated concentration can be obtained from the top without the need for stirring.

Therefore, in such a case, what is necessary is just to stir from the time when the density | concentration of the aqueous solution of the slaked lime obtained by dissolving the slaked lime microparticles is almost dissolved.

Of course, when the slaked lime particles to be used are relatively coarse, the mixture is stirred from the beginning of the operation, and sometimes even when the slaked lime particles are fine, they may be stirred from the beginning.

Stir at least after dissolving the fine particles.

The strength of the agitation should be within a range in which the Soseok-hee particles flowing by stirring do not overflow from the top of the bath. However, when the stirring speed is too high, the slaked lime particles flow to the high level, so that the height of the dissolution tank needs to be unnecessarily high. It is not preferable because the power is also high.

According to the experimental results, as shown in FIG. 1, in the case of the turbine type stirring blade, the stirring speed is sufficient to be 1 m / sec or less, preferably 0.5 m / sce or less, so that the flow rate of water supplied from the bottom is set at the top of the dissolution tank. At 2 m / sec or less, preferably 1 mm / sec or less, to avoid unnecessarily increasing the dissolution tank height.

Next, the apparatus used by this invention is demonstrated.

As shown in FIG. 1 to FIG. 4, the slaked lime dissolution tank 1 used in the present invention has at least a portion (the slaked lime fluidized bed) 2 through which the lower slaked lime particles flow is inclined back-vertical type. An overflowing liquid container 5 having a hydrated lime supply port 3 and an aqueous solution extraction pipe 4 of hydrated water is provided at the upper end of the tank, and a water supply pipe 6 is provided at the bottom of the tank 1.

The water supply pipe 6 is downward and it is preferable to prevent backflow of the slaked lime slurry.

Various means can be used as a means for stirring-flowing slaked lime.

As one of them, as shown in FIG. 1, a stirring blade may be used, and in this case, the shape of the stirring blade 7 may be any shape, but preferably, a turbine type is used so that the slaked lime slurry layer is not deposited on the bottom surface. It is to be installed near the bottom as much as possible, and to avoid the influence of agitation on the upper part of the tank (1) which is back-traced.

In addition, the upper end of the tank 1 is provided with a cutout so that the flow in the tank 1 is not disturbed when the liquid overflows.

As another means to stir-flow the slaked lime, as shown in FIG. 2, a circulation pump 8 which takes out a part of the liquid from the middle of the dissolution tank and supplies it to the bottom of the tank is installed, and the flow of the slaked lime is stirred and dissolved in the circulation of the liquid. You can also

The discharge pipe 9 connected to this circulation pump 8 can be combined with the water supply pipe 6 of new water.

Although one tip of the discharge tube 9 may be sufficient, it is preferable to divide into several pieces in order to make the slaked lime deposited on the bottom of the dissolution tank 1 as uniform as possible.

As the amount of circulation of the liquid by the circulation pump 8 increases, the slaked lime particles can be flowed more severely, but the amount of circulation is determined according to the flow state of the slaked lime particles.

In addition, the stirring flow of the slaked lime particles in the tank can be performed by a water ejector.

That is, as shown in FIG. 3, the water ejector 10 is attached to the slaked lime dissolution tank to install a water supply port ejected from the foreign ejector 10, and the ejection pipe 11 from the middle of the tank is connected to the water ejector. While circulating, the slaked lime at the bottom of the tank can be flow-dissolved by the fractionation liquid.

One water ejector may be used, but a plurality of water ejectors may be installed depending on the size of the slaked lime dissolution tank to be used to stir-flow the entire slaked lime in the tank.

As another stirring method, as shown in FIG. 4, one or two or more stirrers 12 which rotate in the vertical direction at the bottom of the slaked lime dissolution tank may be provided, and the slaked lime may be stirred and flown by rotating them.

The supply of slaked lime to the slaked lime dissolution tank (1) may be carried out by an appropriate method from the slaked lime feed port (3), but in order to prevent the scattering of the slaked lime powder, a bag filter (14) on the bag or carrier of the slaked lime It is good to connect the pipe 15 connected to the N-axis, suction it by a suction fan 16, and feed it from the calcined lime supply port 3 via the bag filter 14 and the rotary valve 17.

Reference numeral 18 is a compressor for washing and dropping the powder attached to the bag filter.

The slaked lime may be put in a predetermined amount in the slaked lime dissolution tank in advance to operate, and the slaked lime may be supplied again when the concentration of the slaked lime solution produced by almost disappearing the slaked lime falls.

The supply of water to the slaked lime dissolution tank 1 is fed at a constant or approximately constant speed, but to do so, for example, by installing a constant pressure water tank 19 to introduce the tap water from the pipe 20 and flowing positively by the pipe 21 flowing therethrough. The water level of the water tank 19 is supplied from the water supply port 6 through the water supply pipe 22 and the flowmeter 23, maintaining a constant water level.

In addition, it is preferable to provide a dissolution tank 1 with a baffle 24 to increase the stirring effect and to prevent the flow height of the slaked lime fine particles from increasing.

In addition, (25) is a tube for continuously extracting insoluble substances contained in calcium carbonate and slaked lime produced by free carbonic acid or the like present in water, and may be provided as necessary.

Using a device as described above, a predetermined amount of slaked lime is added to the slaked lime dissolving tank in water for continuous operation in advance, and then the slaked lime is stirred when the tap water is supplied from the bottom at a speed of 1 mm / sec or less at the top. Approximately 2000 ppm of aqueous solution of slaked lime is continuously obtained until almost disappeared.

In the practice of the present invention, hydrated lime is prepared by adding hydrated lime to an apparatus as shown in FIGS. 1 through 4, supplying water from the bottom at a constant speed while stirring and operating until the hydrated lime is almost eliminated. Once the concentration starts to drop, you can stop the operation and add new lime. Preferably, however, as shown in FIG. 5, the two slaked lime dissolution tanks are installed such that the slaked lime demand liquid extraction pipes are connected to the water pipes of the other tanks by a switching valve, and are operated while switching sequentially.

That is, the water supply pipes 6 and 6 'and the insoluble matter outlet 24 and 24' at the bottom of the dissolution tank 1 and 1 '. An overflowing liquid container having a stirring vane (7) (7 ') and a slaked lime melted water outlet tube (4) (4') at the upper end of the water supply pipe (6) (6 ') ( 5) The two slaked lime dissolution tanks provided with (5 ') are connected to the feed water pipes (6) and 6' by the switching valves (26) and (26 '). Use the slaked lime dissolution tank device that is connected and installed.

Using such a device, the supply of the slaked lime to the inside of the dissolution tanks 1 and 1 'may be performed by a suitable method from the slaked lime feed port 3, 3', but to prevent the scattering of the slaked lime powder, A tube 15 connected to the bag filter 14 is connected to the container 13 and sucked by the suction fan 16 and passed through the bag filter 14 and the rotary valve 17 to supply the hydrated lime 13. It is good to supply by (13 ').

Reference numeral 18 denotes a compressor for washing and dropping the powder attached to the bag filter.

The slaked lime may be operated by putting a predetermined amount into the slaked lime dissolving tank in advance, and when the concentration of the slaked lime solution produced by almost eliminating the slaked lime decreases.

The supply of water to the dissolution tanks 1 and 1 'is supplied at a substantially constant speed, but for this purpose, for example, a constant pressure water tank 19 is provided to introduce the water flow from the pipe 20 to the pipe 21 flowing over. While maintaining the water level of the constant pressure water tank (19) by supplying from the water supply pipe (6) through the water supply pipe (22), the flow regulator 23, and rotating the tube wing (7) at low speed to dissolve the slaked lime flow dissolved in the top of the tank The liquid taken out from the outlet pipe 4 is introduced into the other dissolution tank 1 'via the water supply pipe 6' via the pipe 27 'by the switching valve 26, and in the same manner, the upper end of the tank 1'. This is a device for continuously taking out the slaked lime dissolved water from the dissolved water extraction pipe 4 '.

In this case, the liquid flowing out from the first dissolution tank 1 is almost saturated solution when the slaked lime is sufficiently present in the dissolution tank 1, and does not need to be introduced into the second dissolution tank 1 'and may be taken out as it is. If it operates, the slaked lime in the dissolution tank 1 will become small, and the density | concentration of the slaked lime solution obtained from the slaked lime aqueous solution extraction pipe 4 will gradually fall.

The solution obtained from the 1st dissolution tank 2 is introduce | transduced into the 2nd dissolution tank 1 'at least before the density | concentration of this aqueous solution of slaked lime begins to fall.

In this way, saturated aqueous solution of slaked lime can be continuously obtained while fully utilizing the slaked lime of the first dissolution tank 1.

After consuming the slaked lime of the first dissolution tank 1, the water supply from the constant pressure water tank 19 is lowered by the switching valve 28 to the second dissolution tank.

At this time, the slaked lime exists sufficiently in the 2nd dissolution tank 1 ', and the aqueous solution obtained from the melted water extraction pipe 4' is obtained in substantially saturated concentration.

In the meantime, the insoluble matter in the first dissolution tank 1 is removed from the water-discharge outlet 25, and a new amount of slaked lime is added to fill the water.

Then, before the concentration of the aqueous solution of slaked lime obtained from the second dissolution tank begins to decrease, the aqueous solution from the second dissolution tank 1 'is introduced into the first dissolution tank 1 by the switching valve 26 and operated in the same manner. Saturated limestone aqueous solution is obtained from the aqueous solution extraction pipe 4 of a 1st dissolution tank.

By sequentially switching in this manner, a saturated aqueous solution of slaked lime can be continuously produced while completely utilizing the raw slaked lime.

Example 1

A turbine-type stirring blade having an outer diameter of 50 mm was attached to the inside of a transparent soft vinyl material tank having an inner diameter of 77 mm at the bottom, an inner diameter of 146 mm at the top, and a height of 2,460 mm, to obtain a dissolution tank as shown in FIG.

The melter was filled with water, and 1.43 kg of hydrated lime (containing 80% by volume of fine particles of 63μ or less) (approximately two days of continuous operation equivalent) was added to flow the water from the bottom to 0.8mm / After 24 hours, the stirring blade was rotated at a circumferential speed of 0.5 m / sec, and the aqueous solution of slaked lime was continuously taken out from the upper end of the bath.

The change of the concentration of this aqueous solution with time is indicated by the curve A of FIG.

As is apparent from this drawing, an aqueous solution of slaked lime at a constant concentration (about 2,000 ppm) is continuously obtained until there is almost no undissolved slaked lime.

Example 2

In Example 1, the aqueous solution of slaked lime was taken out in the same manner as in Example 1 except that the flow rate of the feed water from the bottom was 0.5-1.0 mm / sec and the rotation speed of the stirring blade was changed to the range of 0.25-1 mm / sce.

In either case, an aqueous solution of slaked lime having a concentration of about 2,000 ppm was obtained in the same manner as in Curve A.

Moreover, the height of the fluidized bed portion of the slaked lime particles at this time was 1,600 mm-1,800 mm.

Comparative Example 1

Using a cylindrical transparent vinyl chloride dissolution tank with an internal diameter of 146 mm and a height of 2.400 mm, 1.3 kg of hydrated lime was added (rotating the stirring blade at a circumferential speed of 0.5 mm / sec after 6 hours as in Example 1), and the tap water flow rate was 0.2 mm / from the bottom. It was supplied in sec and the aqueous solution of slaked lime was taken out from the top.

As shown in the curve of FIG. 6, the longitudinal change of the aqueous solution suddenly decreased in concentration after 12 hours, and a stable aqueous solution of slaked lime was not obtained.

Claims (1)

The slaked lime dissolution tank 1 has at least a lower portion thereof having a reverse cone or inverted pyramid shape, the upper part of which has a slaked lime feed port 3 and a tank 1 having a slaked lime solution outlet tube 4. And a water supply pipe 6 and a stirring means are installed at the bottom of the tank 1 to supply water from the bottom of the tank 1 at a substantially constant rate, and to take out the aqueous solution of lime from the top while flowing and dissolving the lime. An apparatus for producing a slaked lime solution, characterized in that the.

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