JP2002155271A - Snow melting agent and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a snow-melting agent capable of strongly fixing to ice and snow surfaces and provide a method for producing the snow-melting agent. SOLUTION: This snow-melting agent comprising a granulated product E in which seed particles C containing sodium chloride crystals are coated to be surrounded with granulated layers containing calcium chloride is produced by fluidizing the seed particles C in a fluidized layer 1 and spraying a calcium chloride-containing solution B to the particles during fluidizing the seed particles C in the fluidized layer 1 and irregularly forming a large number of protrusions by growing granulated layers in silver frost shapes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snow melting agent comprising granulated calcium chloride and a method for producing the same.

[0002]

2. Description of the Related Art As a method for granulating such granules containing calcium chloride, the inventors of the present invention spray a calcium chloride aqueous solution while fluidizing seed particles in a fluidized bed to form granules. It has been proposed to produce a granulated product composed of calcium chloride hydrate having a predetermined number of water molecules by adjusting the partial pressure of water vapor in the fluidized bed during the production. Also, by setting the spray height of the aqueous solution of calcium chloride relatively high relative to the height of the stationary bed of the fluidized bed,
It has also been proposed to produce granules containing confetti-shaped particles. Therefore, when such a calcium chloride granule is used as a snow melting agent, the protrusions on the surface of the granulated material having a confetti shape bite into the ice snow surface, so that the snow melting agent can be firmly fixed to the ice snow surface. it can.

[0003]

However, in this conventional method, granules in the shape of confetti are produced by increasing the spraying height of the calcium chloride solution in the fluidized bed because of the spraying height. This is because the calcium chloride solution becomes fine droplets and adheres to the surface of the seed particles dot-to-dot, so that the size of the projections cannot be made too large, and the shape of the projections is smooth. Most are hemispherical, that is, granules in a spinous state are obtained. Therefore, even if the granulated material is used as a snow melting agent, when the snow melting agent is sprayed on a relatively soft fresh snow surface, for example,
As described above, it is possible to improve the fixability by making the protrusions bite into the snow surface, but when spraying on, for example, a tightly closed ice barn, the protrusions become insufficiently bitten and are blown off by strong winds There is a possibility that the ice and snow surface at the scattered location cannot be reliably melted due to being flipped off by running of the car.

The present invention has been made in view of such a background, and provides a snow melting agent having a higher fixability to an ice and snow surface than a snow melting agent formed of such spinous granules. It is an object of the present invention to provide a method for producing a snow melting agent.

[0005]

Means for Solving the Problems In order to solve the above problems and achieve such an object, a snow melting agent of the present invention comprises a seed particle containing sodium chloride crystals and a compound containing calcium chloride around the seed particles. It is characterized by comprising a granulated material coated with a granular layer, wherein a large number of protrusions formed by the granulated layer growing like ice are irregularly formed on the surface of the granular material. Therefore, in a snow melting agent made of such a granulated material, a large number of irregularly formed rime-like projections on the surface of the granulated material bite into the ice and snow surface, and are blown away by wind or applied to an automobile. Since the protrusions are more likely to bite into the icy and snowy surface by being stepped on the tire without being flipped off, it is possible to provide a snow-melting agent having a higher fixing property.

By the way, if the projections in the snow melting agent are too soft, the projections are surely formed even when the ice snow surface is tightly tightened like an ice barn, even if it has a sharp pyramid shape as described above. In addition, there is a possibility that it may not be able to bite, and projections are shaved into fine powder during the manufacturing process of the snow melting agent or when the snow melting agent is packed and transported, thereby impairing the working environment at the manufacturing site or spraying. When doing so, there is a possibility that the snow melting agent becomes round and the biting ability on the ice and snow surface is impaired. For this reason, it is desirable that the hardness of the projection be 0.5 kg or more.
The fact that the hardness of the projection is 0.5 kg or more means that the projection does not break when a weight of less than 0.5 kg is placed on the projection. In particular, in order to grow projections having such hardness, it is desirable to coat calcium chloride dihydrate as the above-mentioned granulated layer.

The method for producing a snow melting agent according to the present invention is a method for producing a snow melting agent comprising a granulated material in which a granulated layer containing calcium chloride is coated around seed particles containing sodium chloride crystals. By spraying a solution containing calcium chloride while flowing the seed particles in the fluidized bed, the granulated layer grows like ice on the surface of the granulated material, and a number of protrusions are irregularly formed. It is characterized by forming.
However, it can be considered that the above-described granulated material can be produced by the production method as follows.

That is, the sodium chloride crystals contained in the seed particles in the present invention have a cubic crystal structure called a so-called rock salt type structure or a salt type structure.
On the surface, corners protruding outward such as an intersection ridge portion between two adjacent lattice surfaces and a corner portion where the three lattice surfaces intersect are formed. Therefore, by injecting a solution containing calcium chloride while fluidizing such seed particles in a fluidized bed, the solution is attached first to the corners protruding outward, and the granulated layer is formed. At this corner, it grows larger than the other parts and becomes a small projection first, and this projection protrudes more outward, so that further solution adheres to the tip and a granulated layer grows. As such granulation is repeated, the small protrusions grow large like rime. In addition, as the seed particles, for example, those obtained by crushing the above-mentioned granulated material in which a granulated layer containing calcium chloride is formed around sodium chloride crystals, and fine particles of a granulated material having a small particle size can be used. Even if it is used, corners due to crushing and protrusions during growth are formed on the surface, so that rime-like protrusions can be formed as in the case of using the sodium chloride crystal itself.

In the method for producing a snow melting agent of the present invention using a fluidized bed as described above, if the temperature in the fluidized bed is too low, the solution adhering to the corners of the seed particles or the tips of the projections may be used. May not be dried quickly, and the solution may spread, which may make it difficult to grow these protrusions to a sufficient size. On the contrary, if the temperature in the fluidized bed is too high, The solution thus dried may be dried before adhering to the seed particles, so that the projections may not be able to grow like ice. For this reason, the temperature in the fluidized bed is desirably set in the range of 60 to 150 ° C. Also, the calcium chloride concentration of the solution injected into the fluidized bed is desirably set within a range of 10 to 73% by weight. If the concentration is higher than this, the viscosity of the solution increases, and the angle of the seed particles increases. Parts and other parts other than the protrusions easily adhere, there is a risk that the granulated material will be entirely round, and conversely, if the concentration is lower than the above range, the growth of the protrusions will be slow and efficient. There is a possibility that granulation is inhibited.

On the other hand, also in the production method of the present invention, the solution is sprayed by setting the jetting height of the solution in the fluidized bed to a predetermined height with respect to the height of the stationary bed in the fluidized bed. In this case, the growth of the rime-like projections can be promoted. In this case, the injection height is desirably set to 100 mm or more with respect to the stationary layer height, and is preferably set to 300 mm or more. More desirable. Further, if the average flow time of the seed particles in the fluidized bed is short, the protrusions cannot be sufficiently grown. On the other hand, even if the average flow time is too long, the grown protrusions may cause another granulated material to flow. The projections cannot be grown beyond a certain size because they are cut or broken by colliding with them.Rather, many powders other than granules are generated by the cut or broken projections. Therefore, it is preferable that the average flow time be controlled within a predetermined range to generate the granulated material serving as the snow melting agent, since the product yield may be reduced.

[0011]

1 to 3 show an example of a manufacturing apparatus according to a first embodiment of a method for manufacturing a snow melting agent according to the present invention. In FIG. 1, reference numeral 1 denotes a fluidized bed, at the bottom of which a pressurizing chamber 3 is formed via a dispersing plate 2. A hot blast stove 6 having an incineration blower 5 and supplying a heated flowing gas A is connected via a moisture adjusting device 7. A spray nozzle 8 is suspended above the dispersion plate 2 in the fluidized bed 1 so as to be able to move up and down, and a tank 10 provided with a concentration adjusting device 9 is connected to the spray nozzle 8 via a supply pump 11. The tank 10 holds an aqueous solution of calcium chloride as a solution B containing calcium chloride. The fluidized bed 1 is supplied by the tank 10, the supply pump 11, and the supply pipe 11A. A supply system for the solution B to be jetted to the nozzle is constituted. Further, a seed hopper 12 is connected to the fluidized bed 1, and the seed hopper 12 holds sodium chloride crystal particles. The sodium chloride crystal particles are dispersed while controlling the supply amount. The seed particles C can be supplied into the fluidized bed 1 from slightly above the plate 2.

Here, in the moisture adjusting device 7,
By radiating or spraying steam or water to the heated and dried fluidizing gas A supplied from the hot blast stove 6 to the pressurizing chamber 3 of the fluidized bed 1, the moisture content of the fluidizing gas A, that is, the humidity is reduced. It is configured to be adjustable to a predetermined value. The supply amount (flow rate) of the supplied steam or water is measured by the flow rate sensor F ₁ , and the temperature and humidity of the flowing gas A whose moisture is adjusted by the moisture adjusting device 7 are measured by the temperature sensors T ₁ and T _1. respectively measured by the humidity sensor H _1.

The concentration adjusting device 9 has a configuration in which a steam pipe for supplying high-temperature steam is provided in the tank 10 to which calcium chloride can be supplied as a raw material. The solution B held at 10 is heated to evaporate water, and the concentration is adjusted to a predetermined value. Incidentally, in this way the calcium chloride concentration density sensor D ₁ of the solution B is fed to the spray nozzle 8 by the supply pump 11 is adjusted, the amount of supply by the flow rate sensor F _2, respectively, are measured. The temperature in the fluidized bed 1 by the temperature sensor T _2,
The humidity humidity sensor H _2, are respectively measured, the humidity of the exhaust D discharged from the fluidized bed 1 is measured further by the humidity sensor H _3.

On the other hand, a vibrating sieve device 14 is connected via a bucket elevator 13 to an outlet of the granulated material E from the fluidized bed 1. The vibrating sieve device 14 is provided with a plurality of sieve nets each having a smaller mesh size from the upper stage to the lower stage, each of which is inclined with respect to a horizontal plane and is capable of vibrating by a vibrating device. The granulated product E can be classified into medium particles F within a predetermined particle size distribution generally regarded as a product, coarse particles G having a larger particle size and fine particles H having a smaller particle size. ing. The number of sieves, the size of the mesh, the inclination angle with respect to the horizontal plane, and the like of the sieve mesh are appropriately set according to the size and shape of the granules E to be separated as products.

The coarse particles G of the granulated material E separated by the vibrating sieve device 14 are partly separated by the damper 15 from the separated medium particles F other than being discharged as a product. Are supplied to the pulverizer 16 together with the medium particles F and pulverized, and further circulated together with the fine particles H through the circulation path 17 as seed particles C to the fluidized bed 1. Here, as shown in FIG. 2, the damper 15 has a feed pipe 18 for feeding the separated coarse particles G branched into two branches, and a shielding plate 19 at a branch portion in the feed pipe 18. Is mounted so as to be swingable, and the shielding plate 19 closes one of the branched feed pipes 18 so that coarse particles G can be selectively fed to the other. The feeding pipe 18 is connected to the crusher 16 and the drying cooler 20, respectively.

Further, the total amount of the medium particles F separated by the vibrating sieve device 14 is as shown in FIG.
1 and temporarily held. The storage 21 includes a hopper 21A for storing the supplied medium particles F, and a vibration conveyor 21 attached to a lower end of the hopper 21A.
B and a supply pipe 21 provided at a middle position in the height direction of the hopper 21A and connected to the crusher 16.
C. And this hopper 21
The medium particles F stored in A are extracted by a necessary amount by the vibrating conveyor 21B and supplied to the drying / cooling machine 20, while passing through the position of the supply pipe 21C to the hopper 2A.
The medium particles F stored in 1A are discharged from the supply pipe 21C and supplied to the pulverizer 16 to be pulverized together with the coarse particles G as described above. The medium particles F extracted by the vibrating conveyor 21B and the coarse particles G selectively discharged by the damper 15 are subjected to an anti-caking treatment in the drying cooler 20, and then subjected to a snow melting agent as a product. Used as

Meanwhile, the humidity sensor H ₃ is the outlet of the fluidized bed 1, which is provided is connected to the scrubber 22, the scrubber 22 is a spray tower 22A whose interior is a cavity shape
It is of a spray type in which exhaust gas D from the fluidized bed 1 introduced into the inside is washed by a washing liquid (wash water) I sprayed from a spray nozzle 22B provided at an upper part in the spray tower 22A. The cleaning liquid I that has washed the exhaust gas D can be held at the bottom of the spray tower 22A, and a scrubber pump 23 is connected to the bottom of the spray tower 22A.
Is connected to the spray nozzle 22B, and the cleaning liquid I after cleaning held at the bottom of the spray tower 22A is supplied to the spray nozzle 22B, circulated, and sprayed into the spray tower 22A again. . The exhaust gas cleaned by the scrubber 22 can be discharged by an exhaust blower 24.

Further, in the manufacturing apparatus, the fluidized bed 1
The solution B in the supply system to the supply system of the solution B
There is provided an anti-consolidation means for preventing stagnation of the slag and preventing its consolidation. That is, as a means for preventing solidification in this manufacturing apparatus, the solution B held in the tank 10 is supplied to the fluidized bed 1 via the supply pump 11 and supplied to the supply pipe 11A which is jetted from the spray nozzle 8 so that the solution B One end of a return pipe 25 is connected near the layer 1 side, and the other end of the return pipe 25 is connected to the tank 10.
A valve 11B is provided between the supply pipe 11A and the connection with the return pipe 25 to the spray nozzle 8 in the fluidized bed 1.

Next, one embodiment of the method for producing a snow melting agent of the present invention in the case of producing a snow melting agent made of the calcium chloride granules E using the manufacturing apparatus having the above-described configuration will be described. The air pushed into the hot blast stove 6 from the pushing blower 4 is heated to a predetermined temperature by heat generated by burning fuel with the air from the incineration blower 5, and is sent to the moisture adjusting device 7 in a dry state. After the dried air is adjusted to have a predetermined moisture content by adding steam or water in the moisture adjusting device 7, the dried
A high-temperature fluidizing gas A of about 180 ° C. is supplied to the pressurizing chamber 3 of the fluidized bed 1, is ejected from the dispersion plate 2, and causes the seed particles C held in the fluidized bed 1 to flow. The seed particles C may be used in the initial stage of operation of the manufacturing apparatus or in the fluidized bed 1.
In the case where there is a shortage of particles in the inside, sodium chloride crystal particles are supplied from the seed hopper 12 and used, and the vibrating sieve 1
Particles containing sodium chloride crystals such as fine particles H circulated from 4 and some medium particles F and coarse particles G crushed by the crusher 16 are supplied from a circulation path 17 and used.

In the fluidized bed 1, a spray nozzle 8 is moved up and down as appropriate to be arranged at a predetermined spray height, and a solution B whose concentration has been adjusted by the concentration adjusting device 9 is supplied from a tank 10. Supply pipe 11 by pump 11
A is supplied through the spray nozzle A and sprayed from the spray nozzle 8. However, the calcium chloride concentration of the solution B adjusted by the concentration adjusting device 9 is set to be as low as about 5% by weight to at most about 60% by weight, and usually within the range of 10 to 73% by weight. Is desirable. The temperature in the fluidized bed 1 at the time of forming the granulated material E is 60 to
The temperature is desirably in the range of 150 ° C. Further, the average flow time of the seed particles C in the fluidized bed 1 is desirably controlled within a predetermined range. The solution B thus sprayed adheres to the surface of the flowing seed particles C and dries, thereby forming a granulated layer of calcium chloride around the seed particles C and enlarging the seed particles C. Generate

Next, the granulated material E thus produced in the fluidized bed 1 is put into the vibrating sieve device 14 by the bucket conveyor 13 and sieved by a plurality of inclined vibrating sieves to obtain a predetermined particle size distribution. Coarse particles G having a larger particle size than the range, and medium particles F within a predetermined particle size distribution range.
And fine particles H having a smaller particle size than this range. Then, as described above, a part of the coarse particles G is selectively discharged to the drying / cooling device 20 through the damper 15 and subjected to an anti-consolidation treatment. And returned to the fluidized bed 1 together with the fine particles H and a part of the medium particles F. The remaining medium particles F are also discharged by the vibrating conveyor 21B, subjected to the anti-consolidation treatment by the drying cooler 20, and are used as a snow melting agent as a product like a part of the coarse particles G.

On the other hand, the exhaust gas D discharged from the fluidized bed 1
Is introduced into the spray type scrubber 22 having the spray tower 22A, and the cleaning liquid I sprayed from the spray nozzle 22B provided in the upper part of the spray tower 22A.
Washed by. That is, the exhaust gas D contains fine particles of calcium chloride generated by drying the aqueous calcium chloride solution B injected into the fluidized bed 1 and sodium chloride generated by shaving from the seed particles C by flowing. Fine particles are contained as solids, and these solids are absorbed and removed by the washing liquid I sprayed into the spray tower 22A, whereby the exhaust D is washed and purified. The exhaust gas D thus cleaned is discharged by the exhaust blower 24 as described above, while the exhaust gas D is discharged.
After being washed at the bottom of the spray tower 22A, the washing liquid I is supplied to the spray nozzle 22B by the scrubber pump 23, and is sprayed again into the spray tower 22A to be used for washing the exhaust D.

However, in such a method for producing a snow melting agent, the seed particles C held in the fluidized bed 1 are circulated from the sodium chloride crystal particles supplied from the seed hopper 12 or the vibrating sieve device 14. Medium particles F, coarse particles G, and fine particles H containing sodium chloride crystals, and the seed particles C are flowed by the flowing gas A, and the solution containing calcium chloride is sprayed from the spray nozzle 8. By spraying B (aqueous calcium chloride solution), the solution B adheres around the seed particles C and is dried, thereby covering the granulated layer made of calcium chloride. Here, the sodium chloride crystal supplied from the seed hopper 12 has a cubic crystal structure called a rock salt type structure or a salt type structure, and has a corner formed on the surface thereof. The sprayed solution B first adheres to the corners, so that a granulated layer is first formed in a protruding shape, and further, the solution B also adheres to the tip of the protruding protrusion to form a granulated layer. While repeating
The projections formed of the granulated layer grow larger than other parts in a frost-like or coral-tree-like manner. As a result, a large number of projections are irregularly formed on the surface of the generated granule E as shown in FIG. It will be formed with a proper arrangement. As shown in the drawing, the sizes of the projections, that is, the lengths and thicknesses thereof are not uniform between the projections, and the shapes and the directions in which the projections extend are also random.

Even when the particles F, G, and H are supplied from the vibrating sieve 14 as the seed particles C, the surfaces of the medium particles F and the coarse particles G are crushed by the crusher 16. The fine particles H which do not pass through the crusher 16 are formed on the surface of the granulated layer covering the periphery of the sodium chloride crystal. The protrusions are formed in the portion although they are small. Therefore, even when the calcium chloride aqueous solution B is jetted while the particles F, G, and H are fluidized in the fluidized bed 1, the medium coarse particles F and G are formed similarly to the case where the sodium chloride crystal itself is used as the seed particles C. Rime-like protrusions grow from the corners of the surface, or protrusions on the surface of the fine particles H grow like rime, whereby a number of rime-like or coral-like protrusions appear on the surface in the same manner as shown in FIG. An irregularly formed granule E is generated. It should be noted that the granulated material E itself generated in this manner can be regarded as a popcorn shape as shown in FIG. 4 because a large number of projections are formed irregularly.

Therefore, in the snow melting agent according to one embodiment of the present invention comprising the granulated material E produced by such a production method, a conventional snow melting agent comprising a spinous-like granulated material, ie, a spherical granulated material. Compared to a snow-melting agent in which small hemispherical projections are relatively regularly formed on the surface of an object, the projections extend longer like rime when sprayed with the snow-melting agent, so that they can penetrate deep into the ice and snow surface. In addition, since the arrangement of the projections is irregular, the grounding stability on the icy and snowy surface is rather high, so that the fixability on the icy and snowy surface can be improved. For this reason, according to the snow melting agent of the present embodiment, not only when the snow melting agent is used on a snow surface, but also when it is used on a hard frozen road surface such as an ice bar, The protrusions are less likely to be blown off by the tires, and rather, the protrusions are further cut into the ice and snow surface by stepping on the tire of the car, so that the ice and snow surface at the scattered portion can be surely melted. .

In the snow-melting agent of the present embodiment, the granulated material E constituting the snow-melting agent is formed by coating a granulated layer containing calcium chloride around seed particles C containing sodium chloride crystals. Since the granulated layer grows and is formed on the frost-like projections, when the snow melting agent is sprayed, the granulation layer containing calcium chloride digs into the frost-like projections. Will be in contact with the ice and snow surface. However, the calcium chloride contained in the granulated layer melts the ice and snow surface more quickly than the sodium chloride contained in the seed particles C. Therefore, the surface where the snow-melting agent is sprayed is immediately melted. Is melted to form a concave portion, the snow melting agent is buried in the concave portion, and the snow melting agent is held in the concave portion by the melted ice and snow water, and furthermore, by the protrusions extending in a rime-like shape. Since the concave portion is formed deeper, the snow melting agent of the present embodiment can further improve the fixability to the ice and snow surface. On the other hand, the sodium chloride contained in the seed particles C has a longer snow-melting effect than the calcium chloride in the granulation layer. It is possible to provide a snow melting agent that can be melted over a period of time.

In the snow melting agent thus constructed, if the frost-grown projections do not have sufficient hardness, the projections will bite into the ice and snow surface, and the above-mentioned effects will be obtained. Needless to say, when the snow melting agent is transported by the bucket conveyor 13 in the manufacturing process of the snow melting agent, at the time of classification by the vibrating sieve device 14, or when the snow melting agent is packed and transported. However, the projections are shaved or broken and become fine powder, which impairs the working environment at the manufacturing site, or when trying to spray on ice and snow, the surface of the snow melting agent becomes round, and the above-mentioned The effect may not be achieved. Therefore, the hardness of the projection is desirably 0.5 kg or more, that is, when a weight of less than 0.5 kg is placed (4.
(When a force of less than 9 N is applied), the hardness is desirably set to such a degree that the projection is not broken. As described later, calcium chloride has hydrates having various numbers of water molecules. Particularly, in order to form a granulated layer capable of growing such projections, calcium chloride dihydrate is used as the granulated layer. It is desirable to coat the hydrate.

On the other hand, in one embodiment of the method for producing a snow melting agent according to the present invention described above, the solution B containing calcium chloride is injected while the seed particles C containing sodium chloride crystals are fluidized in the fluidized bed 1. As described above, the granulation layer containing calcium chloride is formed around the seed particles C while the projections grow like rime, as shown in FIG.
It is possible to reliably and efficiently produce the snow melting agent composed of the granulated material E as shown in FIG. However, in the production method using such a fluidized bed 1, first, if the temperature in the fluidized bed 1 is too low, sodium chloride crystals as the seed particles C or crushed medium coarse particles F, Even if the solution B adheres to the corners of G, the protrusions formed on the corners, or the protrusions formed on the surface of the fine particles H as the seed particles C, the solution B is quickly dried to remove the protrusions. There is a possibility that the solution B cannot be formed or sufficiently grown, and the solution B spreads over the entire surface of the seed particles C, so that only the spherical granules E can be obtained. On the other hand, even if the temperature in the fluidized bed 1 is too high, the solution B injected into the fluidized bed 1 will not
The fluid in the fluidized bed 1 may be immediately dried before adhering to the fluidized bed, and may not be able to produce the granulated material E having the rime-like projections. It is desirable that the temperature be set in the range of 60 to 150 ° C.

Second, the calcium chloride concentration of the solution (in the present embodiment, the aqueous solution of calcium chloride) B containing calcium chloride injected into the fluidized bed 1 is also:
If this is too high, the viscosity of the solution B also becomes high, and even if it adheres to the corners of the seed particles C or to a portion other than the tip of the projection, the solution B is dried as it is to form a granulated layer. May not be able to grow sufficiently.
On the other hand, even if the calcium chloride concentration of this solution B is too low, the growth of the projections by the solution B attached to the corners and the projections may be slowed, and efficient production of the granulated product E may be hindered. The calcium chloride concentration of the solution B is desirably set within the range of 10 to 73 wt% as in the present embodiment.

Third, the average flow time of the seed particles C in the fluidized bed 1 also depends on the temperature in the fluidized bed 1 and the concentration of the solution B.
Again, while the projections may not be able to grow sufficiently in a rime-like manner, even if this average flow time is secured unnecessarily long to produce granules E in which the rime-like protrusions grow long and large. When the granules E collide with each other due to the flow in the fluidized bed 1, the excessively long protrusion is scraped or broken, so that a protrusion having a certain size or more is rarely formed. Rather, in this case, since many of the shaved or broken protrusions are formed as powder, the working environment may be deteriorated in the same manner as in the above case. Of the calcium chloride, the proportion of the calcium chloride used as the granulated layer covering the granulated product E of the snow melting agent is reduced, that is, the product yield may be reduced. Therefore, it is desirable that the average flow time is also controlled within a predetermined range as in the present embodiment.

In the method for manufacturing a snow melting agent thus configured, since the fluidized bed 1 is the seed particles C containing sodium chloride crystals, the exhaust gas discharged from the fluidized bed 1 D contains fine particles of sodium chloride in addition to fine particles of calcium chloride as described above. However, when the sodium chloride fine particles are washed in the scrubber 22, they do not dissolve in the washing solution in which calcium chloride is dissolved but float as particles in the washing solution, whereby the washing solution becomes a highly viscous slurry. On the other hand, in the present embodiment, the scrubber 22 for cleaning the exhaust gas D discharged from the fluidized bed 1 is of a spray type, and thus the cleaning liquid I is formed into a highly viscous slurry. Even if the cleaning liquid I is circulated to the spray nozzle 22B and used again for cleaning, the cleaning liquid I will not be clogged at the restricting portion unlike a venturi scrubber.

That is, the spray type scrubber 22 is provided with the spray tower 22A having a hollow inside as described above, and is provided with the cleaning liquid I sprayed from the spray nozzle 22B provided in the spray tower 22A. Since the introduced exhaust gas D is cleaned, the cleaning liquid I does not adhere to a portion of the venturi scrubber where the exhaust gas D is sucked, such as the above-described throttle portion. Even if it is, it is possible to prevent a situation in which the suction of the exhaust gas D is hindered and the cleaning is hindered, and it is possible to manufacture the granules E smoothly and efficiently. In addition, such a spray-type scrubber 22 has a lower gas flow rate of the exhaust D to be processed than, for example, the above-described venturi-type scrubber and the like.
As a result, the pressure loss is reduced.
Exhaust blower 24 for exhausting the cleaned exhaust from A
This also has the advantage of requiring only a small amount of power, and therefore, according to the present embodiment, there is also obtained an effect that more economical granulation becomes possible.

According to the present embodiment, the solution B containing calcium chloride is sprayed onto the seed particles C flowing in the fluidized bed 1 and adheres to the surface thereof, and the solution B is heated by the flowing gas A for heating. Since the granules E are generated by drying, granulation is possible using the solution B having a low calcium chloride concentration, and there is little danger of equipment corrosion, and the solution B is concentrated to a high concentration. No heating means is required. Further, with respect to calcium chloride 2,4,6 hydrate generally used as a product, even when the temperature in the fluidized bed 1 is relatively low, for example, about 60 to 150 ° C., the vapor pressure is appropriately adjusted. Granulation can be performed by setting, and the temperature in the fluidized bed 1 is controlled by the hot air stove 6.
By heating the flowing gas A such as air by
It is possible to relatively easily raise the temperature or maintain the temperature stably.

Further, in the manufacturing apparatus of the present embodiment,
The moisture of the fluidizing gas A supplied to the fluidized bed 1 is adjusted by the moisture adjusting device 7, and the moisture of the solution B injected into the fluidized bed 1 is adjusted by the concentration adjusting device 9 to have a concentration of the solution B. Since the adjustment is performed by adjusting, that is, the amount of water supplied to the fluidized bed 1 is adjusted, the partial pressure of steam in the fluidized bed 1 can be adjusted by these adjustments. Thus, by adjusting the partial pressure of water vapor in the fluidized bed 1 in this way, based on a vapor pressure diagram according to the number of water molecules of calcium chloride hydrate as shown in FIG. The vapor pressure of calcium chloride can be set to a vapor pressure according to the number of water molecules of the hydrate of the calcium chloride granule E to be granulated in accordance with the temperature in the fluidized bed 1.

That is, for example, when the temperature in the fluidized bed 1 is 90
° C, calcium chloride dihydrate (CaCl ₂
When producing 2H ₂ O), the calcium chloride vapor pressure is set to about 5.3 kPa (40 mmHg).
The water vapor partial pressure in the fluidized bed 1 is adjusted by the moisture adjusting device 7 and the concentration adjusting device 9 respectively. In this embodiment, the setting of the vapor pressure of calcium chloride in the fluidized bed 1 by adjusting the partial pressure of the water vapor is performed by the temperature sensors T ₁ and T ₂ , the humidity sensors H _{1 to} H ₃ , and the flow sensors F ₁ and F _2. , And the measurement result of the concentration sensor D ₁ , preferably automatically. Therefore, according to the granulator having the above configuration, by adjusting the partial pressure of steam in the fluidized bed 1 in accordance with the temperature in the fluidized bed 1 as described above, the predetermined calcium chloride hydrate to be granulated can be obtained. The vapor pressure of the calcium chloride hydrate in the fluidized bed 1 can be set to the vapor pressure according to the number of water molecules of the water, whereby the granulated product E of calcium chloride hydrate having the desired number of water molecules can be produced. can do. Therefore, it is possible to reliably produce the granulated product E of calcium chloride hydrate having an appropriate number of water molecules according to the use as a product, and it is possible to efficiently and simply perform the subsequent processing. .

Further, in the manufacturing apparatus having the above configuration, in the supply system for supplying the solution B to the fluidized bed 1,
Since the return pipe 25 is provided as an anti-consolidation means,
According to the production method of the present embodiment, when the granulation of the calcium chloride granulated material E is temporarily stopped or the granulation operation is completed, the solution B stays and causes consolidation to occur. It is possible to prevent a situation that may cause trouble when resuming granulation. That is, the fluidized bed 1 is sprayed from the spray nozzle 8.
When the injection of the solution B into the inside is interrupted and the granulation is stopped, the solution B is left as it is in the supply pipe 11A and stays in the supply pipe 11A to cause solidification and clogging, and then the granulation is restarted. At this time, even if an attempt is made to spray the solution B from the spray nozzle 8, the solution B may not be able to be supplied to the supply pipe 11A. In this embodiment, however, the supply is performed by closing the valve 11B. Tube 11
The solution B remaining in A is returned to the tank 10 via the return pipe 25.
Or by circulating the solution B through the supply pipe 11A and the return pipe 25,
It is possible to prevent the solution B in 1A from staying and prevent the solution B from solidifying.

Further, in the present embodiment, as described above, the water vapor partial pressure in the fluidized bed 1 is adjusted by the moisture adjusting device 7 and the concentration adjusting device 9 so that the predetermined calcium chloride hydrate to be granulated can be formed. The vapor pressure of calcium chloride hydrate in the fluidized bed 1 is set to the vapor pressure according to the number of water molecules,
Granules E composed of calcium chloride hydrate having a desired number of water molecules can be produced. However, if the partial pressure of water vapor in the fluidized bed 1 is set sufficiently lower than the vapor pressure of calcium chloride, seeds can be produced. Protrusions are easily formed around the particles C. Moreover, in the manufacturing apparatus, the spray nozzle 8 from which the solution B is sprayed can be moved up and down as described above, and the spray height of the solution B is set to be higher than the height of the stationary layer in the fluidized bed 1. Even more desirably, even if the diameter is set to 300 mm or more, the sprayed solution B becomes droplets and adheres to the surface of the seed particles C, but in the present embodiment, the corners. It will be easier. The injection height of the solution B with respect to the height of the stationary layer is 30
It is more preferable that the thickness be 0 mm or more, but if it is 100 mm or more, a sufficient effect can be obtained.

On the other hand, in the present embodiment, when adjusting the partial pressure of water vapor in the fluidized bed 1 as described above, the moisture amount, that is, the humidity of the flowing gas A supplied to the fluidized bed 1 by the moisture adjusting device 7 is adjusted. In addition to the adjustment, the concentration of the solution B injected and supplied into the fluidized bed 1 by the concentration adjusting device 9 is adjusted. It is also possible to arrange to adjust the pressure. However, especially when it is attempted to adjust the partial pressure of water vapor only by the concentration adjusting device 9, the responsiveness to the fluctuation of the temperature in the fluidized bed 1 may be insufficient. At the same time, while the concentration of the solution B is maintained at an appropriate concentration by the concentration adjusting device 9, the moisture of the flowing gas A is adjusted by the moisture adjusting device 7, that is, the moisture adjusting device 7 and the concentration adjusting device 9 are used in combination. Thus, it is desirable to adjust the partial pressure of water vapor in the fluidized bed 1.

In the present embodiment, the flow rate of steam or water supplied to the moisture adjusting device 7, the temperature and humidity of the flowing gas A whose moisture has been adjusted, and the concentration of the solution B adjusted by the concentration adjusting device 9. And the flow rate, as well as the temperature and humidity in the fluidized bed 1 and the humidity of the exhaust D from the fluidized bed 1, are temperature sensors T ₁ and T ₂ , humidity sensors H _{1 to} H ₃ , flow sensors F ₁ and F ₂ , respectively. It is measured by the concentration sensor D _1. From the measurement results of at least the temperature in the fluidized bed 1 and the humidity of the exhaust gas D from the fluidized bed 1, the vapor pressure of the calcium chloride hydrate is determined based on the vapor pressure diagram of the calcium chloride hydrate described above. It is possible to reliably adjust the partial pressure of water vapor so as to be optimally set. In addition to this, in the present embodiment, the temperature and humidity (moisture content) of the flowing gas A, the concentration and the flow rate of the solution B containing calcium chloride are calculated using a computer or the like based on the measurement results of other sensors. The automatic control enables more accurate adjustment of the water vapor partial pressure.

Further, in the present embodiment, the granulated material E discharged from the fluidized bed 1 is separated into coarse particles G, medium particles F and fine particles H by the vibrating sieve device 14, and a predetermined particle size distribution range The medium particles F and the coarse particles G therein are subjected to an anti-consolidation treatment by the drying cooler 20 to obtain a product, and the remaining pulverizer 16
The coarse particles G, the medium particles F, and the fine particles H crushed as described above are directly circulated to the fluidized bed 1 as seed particles C. Therefore, for example, when the amount of calcium chloride in the granulated material E discharged as the product and the amount of calcium chloride in the solution B supplied as a raw material are balanced, the seed hopper 12 may be used in the initial operation or in the seed particles. It is only necessary to supply sodium chloride crystals as seed particles C to the fluidized bed 1 as necessary, for example, when C is insufficient. Since the seed particles C can be covered by the circulating particles during normal operation, it is efficient. Driving can be achieved.

However, when circulating the particles separated by the vibrating screen device 14 in the fluidized bed 1,
If the amount of the circulated particles is too large relative to the amount of the product particles, the yield of the product is deteriorated, while the amount of the circulating particles is too small relative to the amount of the product particles. In this case, the amount of seed particles C in the fluidized bed 1 is insufficient, and the sodium chloride crystals must be frequently replenished from the seed hopper 12, so that the operation becomes complicated. Accordingly, the calcium chloride granules E discharged from the fluidized bed 1
The ratio of the total weight of the particles to the weight of the above-mentioned particles to be separated into a product, that is, the circulation ratio of the calcium chloride granule E is 1.
It is desirable to set in the range of 5 to 10. In the present embodiment, a part of the medium particles F separated by the vibrating sieve device 14 is circulated to the fluidized bed 1. However, all the medium particles F are sent to the drying cooler 20 to be used as a product. It may be used as a snow melting agent.

Further, in this embodiment, the vibrating sieve device 14 is configured to separate the granulated material E by vibrating a plurality of stages of the sieve mesh inclined with respect to the horizontal plane by the vibrating device. By inclining the screen, it is possible to increase the size of the openings with respect to the size of the particles to be separated, and together with vibrating the sieve screen, prevent the occurrence of clogging and perform efficient separation. Can be achieved. Moreover, in the present embodiment, of the particles separated by the vibrating sieve device 14, only the coarse particles G and the medium particles F, which are products, are sent to the drying cooler 20 to be cooled.
The remaining crushed coarse particles G, medium particles F, and fine particles H are circulated in the fluidized bed 1 without cooling, so that the temperature in the fluidized bed 1 is not greatly reduced by the circulation of these particles. Thus, it is possible to efficiently generate the calcium chloride granules E that are thermally efficient.

Next, FIG. 6 shows an example of a manufacturing apparatus according to a second embodiment of the method for manufacturing a snow melting agent of the present invention, and shows parts common to the manufacturing apparatus shown in FIGS. Are assigned the same reference numerals and description thereof is omitted. That is, in this manufacturing apparatus, in the scrubber 22 of the manufacturing apparatus shown in FIGS. 1 to 3, the supply path in which the cleaning liquid I held at the bottom of the spray tower 22A is supplied to the spray nozzle 22B by the scrubber pump 23 is in the middle. It is branched to form a circulation path 31, and this circulation path 31 is connected to the tank 10 holding the solution B containing calcium chloride. Further, in this manufacturing apparatus, the supply pipe 11A is further provided as a second solidification preventing means for the solution B.
To the supply pump 11 side through a valve 32A.
The other end of the drainage pipe 32 is connected to the scrubber 22. In the manufacturing apparatus, a valve 11C is provided on the fluidized bed 1 slightly in the supply pipe 11A from the connection with the drain pipe 32.

In the manufacturing method according to the second embodiment of the present invention using the manufacturing apparatus configured as described above, a part of the cleaning liquid I after cleaning the exhaust gas D held in the scrubber 22 is transferred to the circulation path. The solution B containing calcium chloride is circulated through the tank 10 through the supply pipe 11A through the tank 10 through the supply nozzle 11A.
And supplied to the fluidized bed 1. However, as described above, the cleaning liquid I that has cleaned the exhaust D has the calcium chloride fine particles discharged together with the exhaust D from the fluidized bed 1 collected and dissolved in the cleaning liquid I sprayed from the spray nozzle 22B. Thus, since the washing liquid I has a certain concentration of calcium chloride, the cleaning liquid I is sprayed to the fluidized bed 1 through the tank 10 to generate the granules E, whereby the solution B having the same concentration is discharged from the tank 10. Even if it is supplied to the fluidized bed 1, the amount of calcium chloride as a raw material to be supplied to the tank 10 can be reduced, and the more economical generation of the calcium chloride granules E can be promoted.

In the method for manufacturing a snow melting agent according to the second embodiment, calcium chloride is dissolved in the cleaning liquid I after cleaning held at the bottom of the spray tower 22A of the scrubber 22 as described above. With seed particles C
The fine particles of sodium chloride contained in the above are also included. Therefore, by circulating such a washing liquid I through the circulation path 31, the solution B containing sodium chloride together with calcium chloride is held in the tank 10, and the solution B is injected into the fluidized bed 1. Thus, also in the granulated product E generated in the fluidized bed 1, the solution B containing calcium chloride and sodium chloride adheres around the seed particles C containing sodium chloride crystals and is dried. The mixture of the calcium chloride component and the sodium chloride component is coated as a granulation layer, and the granulation layer made of the mixture grows like ice and many projections are irregularly formed on the surface of the granule E. The Rukoto.

However, in the case of the snow melting agent according to the second embodiment of the present invention comprising such granulated material E, when the snow melting agent is sprayed on the ice and snow surface, the protrusions that have grown in a rime-like manner are similar to those in the first embodiment. Of course, the calcium chloride component in the mixture covering the surface of the granulated material E is dissolved before the sodium chloride component to dissolve the surrounding ice and snow, and thus the surface of the granulated material E Of the mixture, the calcium chloride component elutes first, so that the surface of the granulated material E includes a large number of irregularities after the calcium chloride component begins to melt, including the protrusions and other portions that have grown like rime. Is formed. Therefore, according to the snow melting agent of the present embodiment, in addition to the bite of the rime-like projections, the snow melting agent is more firmly fixed to the ice snow surface also by this unevenness bites into the ice snow surface, After firmly adhering to the ice and snow surface in this way, the sodium melting component in the surface mixture and the sodium chloride of the seed particles C exert a snow melting effect over a long period of time.

As described above, in the snow melting agent of the second embodiment, the seed particles C containing only sodium chloride crystals are used.
As compared with the snow melting agent composed of the granulated material E in which the periphery of the particle is coated with the granulation layer composed of calcium chloride, the unevenness formed on the surface of the powder melts into the ice and snow surface to improve the fixability to the ice and snow surface. The snow melting agent is not blown off even in a strong wind, and the snow melting agent is blown off by the running of the car even when the snow melting agent is sprayed on a frozen road surface, in combination with the effect of the above-mentioned rime-like growth. Can be prevented more reliably. Also, on the other hand,
In addition to the sodium chloride contained in the seed particles C, the mixture surrounding the seed particle C also contains a sodium chloride component. Therefore, the content of sodium chloride contained in the snow melting agent is large, so Since the snow melting effect can be maintained over the entire area, the present embodiment can provide a snow melting agent capable of melting ice and snow at a scattered place more reliably and for a long time. .

Further, in the manufacturing apparatus according to the second embodiment, a solution B containing calcium chloride (including sodium chloride in this embodiment) is held as the second caking preventing means. Fluidized bed 1 from tank 10
Supply pipe 11A and the scrubber 22 are connected to the drainage pipe 3
2 are connected. However, the return pipe 25
Is not a temporary interruption of granulation that can be handled by the anti-consolidation means, but the production of the snow melting agent composed of the predetermined granulated material E is completed, and the operation of forming the granulated material E is completed. For example, when the granulating apparatus is stopped for a time, there is a possibility that the solution B held in the tank 10 may be solidified due to stagnation. Even while the manufacturing apparatus is stopped, steam must be continuously supplied to the tank 10 and stirring must be performed, and it is inevitable that economical efficiency is impaired both thermally and dynamically.

Therefore, in such a case, in the manufacturing method of the second embodiment using the manufacturing apparatus having the second anti-consolidation means, first, the solution B remaining in the supply pipe 11A is returned to the return pipe 25. After returning to the tank 10, the valve 11C is closed and the valve 32A of the drain pipe 32 is opened,
The solution B in the tank 10 is applied to the spray tower 2 of the scrubber 22.
By draining the liquid to 2A, the tank 10 can be emptied to prevent caking. Therefore, in this case, the solution B in the tank 10 can be held in the scrubber 22 together with the cleaning solution I containing the same calcium chloride as described above, so that the solution B and the cleaning solution in the scrubber 22 can be held. It is sufficient to heat only I so that caking does not occur, which is more economical and efficient than preventing caking in the tank 10. Next, when the granulation operation is restarted, the circulation path 31 is supplied from the scrubber 22 by the scrubber pump 23 as described above.
The solution B may be supplied to the tank 10 via the.

By the way, when the granulation operation is completed and the operation is restarted next, usually, the inside of the fluidized bed 1 is first washed, and then the heated flowing gas A is supplied from the hot blast stove 6. While drying and raising the temperature in the fluidized bed 1,
The concentration of the solution B must be adjusted by concentrating the solution B in the tank 10. In the present embodiment, at least a part of the cleaning solution I can be supplied from the scrubber 22 to the tank 10 via the circulation path 31 as described above. Thus, the concentration time of the solution B before restarting the granulation operation can be shortened. That is, before restarting the granulation operation, for example, 35 to 37 wt.
% Of the aqueous solution of calcium chloride is supplied and circulated, and high-temperature exhaust gas D generated at the time of raising and drying the fluidized bed 1 is introduced into the scrubber 22 to be supplied to the scrubber 22. Together with the heat of the steam, the aqueous calcium chloride solution supplied to the scrubber 22 can be concentrated to a concentration of, for example, about 50% by weight and supplied to the fluidized bed 1 in a short time. Therefore, according to the present embodiment, it is possible to shorten the preparation time required when resuming the granulation operation, and for example, at the beginning of the resumption of the granulation operation, the fluidized bed is not transferred from the scrubber 22 without the tank 10. It is also possible to supply and spray the calcium chloride aqueous solution whose concentration has been directly adjusted to 1 as the solution B, or to omit the tank 10 itself in some cases.

[0051]

As described above, according to the snow-melting agent of the present invention, a granulated layer containing calcium chloride grows on the surface of the granulated material constituting the snow-melting agent in a frost-like manner, and a large number of frosts are formed. Due to the irregular formation of the projections, the biting ability of the snow melting agent on the ice and snow surface can be significantly improved, and in combination with the fact that the seed particles contain sodium chloride crystals, It is possible to reliably stay at the place where the dust is sprayed, and to maintain the snow melting effect for a long time, and according to the method for producing a snow melting agent of the present invention, it is possible to reliably and reliably obtain the snow melting agent having such an excellent effect. It can be manufactured efficiently. The snow melting agent has a hardness of 0.5 kg.
By doing so, the bite on the ice and snow surface is further ensured, the working environment at the manufacturing site is prevented from deteriorating, and the snow melting agent is transported in a bag and transferred from the bag to a sprayer. At the time of replacement, it is possible to prevent the powder from becoming powder. Calcium chloride dihydrate is suitable for the granulated layer. On the other hand, in the production method of the present invention, the temperature in the fluidized bed is set in the range of 60 to 150 ° C., and the calcium chloride concentration of the solution to be jetted is set to 1
0 to 73 wt%, the injection height of the solution containing calcium chloride with respect to the height of the stationary bed of the fluidized bed is 100 mm or more, more preferably 300 mm or more, and the average flow time of the seed particles in the fluidized bed. Is controlled within a predetermined range, it is possible to more reliably or efficiently manufacture a granulated product having the above-mentioned projections, each of which is suitable as a snow melting agent.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing apparatus according to a first embodiment of a method for manufacturing a snow melting agent of the present invention.

FIG. 2 is a sectional view of a damper 15 of the manufacturing apparatus shown in FIG.

FIG. 3 is a sectional view showing a reservoir 21 of the manufacturing apparatus shown in FIG.

FIG. 4 is an enlarged photograph showing a snow melting agent according to the first embodiment of the present invention.

FIG. 5 is a vapor pressure diagram of calcium chloride hydrate.

FIG. 6 is a view showing a manufacturing apparatus according to a second embodiment of the method for manufacturing a snow melting agent of the present invention.

[Description of Signs] 1 Fluidized bed 6 Hot blast stove 8 Spray nozzle 10 Tank 12 Seed hopper 22 Scrubber 31 Circulation path A Flowing gas B Solution containing calcium chloride C seed particles D Exhaust discharged from fluidized bed 1 E Granulated matter F Medium particles of granules E G Coarse particles of granules E H Fine particles of granules E I Cleaning liquid

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuhiro Nishimoto, Hamaichicho, Utazu-cho, Kagawa Prefecture 1-1 Kaisei Kogyo Co., Ltd. (72) Inventor Keiji Ichimura 5-7-20 Sodegaura, Narashino-shi, Chiba A-itec Co., Ltd. (72) Inventor Satoshi Suwa 2--17-15 Tsukuda, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. (72 Inventor Yasushi Tamura 2-17-15 Tsukuda, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. F-term (reference) 4H020 AA02 AB01

Claims (9)

[Claims] The present invention comprises a granulated material in which a granulated layer containing calcium chloride is coated around seed particles containing sodium chloride crystals, and the granulated layer is formed on the surface of the granulated material in a frost-like manner. A snow melting agent, wherein a number of protrusions formed by growth are irregularly formed. 2. The snow melting agent according to claim 1, wherein the hardness of the protrusion is 0.5 kg or more. 3. The snow melting agent according to claim 1, wherein the granulated layer is made of calcium chloride dihydrate. 4. A method for producing a snow melting agent comprising a granulated material in which a granulated layer containing calcium chloride is coated around seed particles containing sodium chloride crystals, wherein the seed particles are flowed in a fluidized bed. By spraying a solution containing calcium chloride while making the surface of the granulated material, the granulated layer grows like ice, forming a number of protrusions irregularly, Production method. 5. The temperature in the fluidized bed is 60 to 150 ° C.
The method for producing a snow melting agent according to claim 4, wherein the temperature is set within the range of. 6. The calcium chloride concentration of the above solution is 10
The method for producing a snow melting agent according to claim 4 or 5, wherein the content is set within the range of ~ 73 wt%. 7. The snow melting agent according to claim 4, wherein the spray height of the solution is set to 100 mm or more with respect to the height of the stationary bed in the fluidized bed. Manufacturing method. 8. The snow melting agent according to claim 4, wherein the spray height of the solution is set to be 300 mm or more with respect to the height of the stationary bed in the fluidized bed. Manufacturing method. 9. The method for producing a snow melting agent according to claim 4, wherein the average flow time of the seed particles in the fluidized bed is controlled within a predetermined range.