JP2002282668A - Slurry storage method and storage apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store fly ashes in form of a slurry for a long duration. SOLUTION: A slurry is supplied to a cylindrical slurry tank 2 made to have a circular bottom part, a rotation truck 3 extended from the rotary shaft installed in the center of the circle of the slurry tank 2 in the outer circumferential direction of the circle is rotated at a period of not shorter than 15 minutes and not longer than 3 hours, and stirring blades 4a attached to a single or a plurality of stirring apparatuses 4 installed on the rotation truck 3 in rotatable manner just like a planet are rotated at a circumferencial speed of 0.01 m/s to 1 m/s. Since the rotation truck 3 and the stirring blades 4a of the stirring apparatuses 4 are rotated at a low speed, the operation motive force can be suppressed to low and since no facility for blowing compressed air or the like is needed, the installation cost can be suppressed to low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for storing a slurry, and more particularly, to a method for pumping a fly ash slurry or the like obtained after washing and desalinating fly ash generated in an incineration plant for municipal solid waste. The present invention relates to a method and a storage device for storing a slurry that can be stored as it can be pumped.

[0002]

2. Description of the Related Art Conventionally, when incinerating fly ash such as municipal waste incineration fly ash is reused as a raw material for cement, it is necessary to avoid troubles in the cement burning process caused by chlorine compounds in the incineration fly ash. The ash is washed with water to remove chlorine compounds.

Approximately 0.5% after chlorine compounds are removed by washing with water
When using incinerated fly ash with residual chlorine as a raw material in the cement manufacturing process, it is necessary to treat fly ash received during the suspension of cement kiln after suspension,
Since the ratio of the amount of fly ash used to all the raw materials is limited to a certain amount due to restrictions on the amount of chlorine allowed in the raw materials and the capacity of the fly ash slurry pumping facility, the fly ash slurry after washing and desalination is reduced to 2%. It is necessary to store it in a state that can be pumped by a pump for about 4 months, and to add it to the raw material while adding it little by little to the constantly processed product. However, no attempt has been made for long-term storage of fly ash as a slurry.

On the other hand, Japanese Patent Application Laid-Open No. 6-299171 discloses that in order to prevent sedimentation of solids in the slurry, the bottom of the tank is inclined, the slurry is sucked from the lower side of the slope, and the slurry is pumped to the upper part of the slurry. A method and apparatus for stirring a slurry by discharging is disclosed.

Japanese Patent Application Laid-Open No. Hei 7-216369 discloses that the supernatant liquid of a slurry is sucked from a suction port attached to a float floating on the liquid surface, and is pressurized by a pump to form a circulating flow in a tank to homogenize the slurry. A technique for keeping the information is disclosed.

[0006]

However, Japanese Patent Application Laid-Open No.
The slurry stirring method and apparatus described in JP-A-299171 and JP-A-7-216369 are for handling a CWM which is made into a slurry by dispersing and suspending fine powdered coal in water. However, it is not suitable to use the fly ash slurry or the like after the fly ash generated in the municipal solid waste incineration plant is washed with water and desalinated for the production of cement.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a slurry storage method and a storage device capable of storing fly ash as a slurry for a long period of time.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventor has conducted various studies and conducted various tests.
In a cylindrical slurry tank, it has been found that by setting the cycle of the rotary cart and the cycle of the stirring blade within a certain range, it is possible to secure the pumping property for a long period of time while suppressing the required power. It was completed.

That is, in the method of storing slurry according to the present invention, the slurry is supplied into a cylindrical slurry tank having a circular portion at the bottom, and the slurry is supplied from a rotating shaft installed at the center of the circular shape of the slurry tank to the outer circumferential direction of the circle. Is rotated at a period of 15 minutes or more and 3 hours or less, and a stirring blade attached to one or a plurality of stirrers rotatably mounted in a planetary shape on the rotating carriage is 0.01 m in length. It is characterized by being rotated at a peripheral speed of not less than 1 m / s and not more than 1 m / s.

According to the present invention, since the slurry is maintained in a state capable of being pumped for a long period of time and the rotating carriage and the stirring blades of the stirrer are rotated at low speed and stirred, the slurry is stored while the operating power is kept low. be able to.

According to the above method, when the slurry of fly ash generated from the municipal waste incineration plant is stored, the fly ash generated from the stoker furnace etc. of the incineration plant is washed with water and desalted to be used as a cement raw material. The separation of water can be prevented, and the fly ash slurry after the water washing and desalting treatment can be stored for a long period of time while maintaining pumpable properties.

Further, the fly ash slurry storage device according to the present invention comprises a cylindrical slurry tank having a circular portion at the bottom and a rotary shaft installed at the center of the circular shape of the slurry tank. And a rotating carriage extending in the outer circumferential direction of a circle, and one or more agitators having stirring blades that are rotatably mounted in a planetary manner on the rotating carriage and rotate about a rotation axis. Unlike the slurry basin used in the wet cement production process of the above, no equipment for blowing compressed air is required, so that the equipment cost can be kept low.

[0013]

Next, a specific example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a slurry storage device according to the present invention. The storage device 1 is roughly divided into a cylindrical slurry tank 2 and a rotating truck 3 rotating at a constant speed in the slurry tank 2. And one or a plurality of stirrers 4 that are rotatably mounted in a planetary manner on the rotating carriage 3 and have rotatable stirring blades 4a.

The whole slurry tank 2 is formed in a cylindrical shape with the bottom 2a being a circular portion. A slurry supply port 9 is provided at the top of the side wall 2b of the slurry tank 2, and a discharge port 10 is provided at the bottom 2a.

The rotary cart 3 rotates around a rotary shaft 5 installed at the center of the circular shape of the slurry tank 2 and extends from the rotary shaft 5 in the outer circumferential direction of the circle.

The agitator 4 has a plurality of agitating blades 4a attached to the rotating carriage 3 and rotating about a rotating shaft 4b.
As shown in FIG. 2, for example, the stirring blade 4a extends four flat steels 4c in parallel in the vertical direction, and
It is fixed by four horizontal members 4d. And FIG.
As shown in FIG. 2, the whole of the stirrer 4 rotates in a planetary manner with the rotation of the rotary carriage 3, and the stirring blade 4a is rotated by a rotating shaft 4b.
Spin around. In this embodiment, two stirrers 4 are used.
However, when a large slurry tank 2 is used, three to four stirrers may be provided in consideration of the mechanical strength of the stirrer.

A roof 6 is provided above the slurry tank 2 for the purpose of suppressing evaporation of water due to direct sunlight or the like. The slurry tank 2 is provided with a water supply pipe 8 for adjusting the water content of the slurry in the tank. Even when the water content of the slurry evaporates, the water is replenished to adjust the viscosity of the slurry (agitating power) within an appropriate range. Can be stored.

Next, as a test example of the slurry storage device having the above configuration, a case where a fly ash slurry generated from a municipal solid waste incineration plant is used and the fly ash slurry is maintained in a pumpable state will be described.

As the fly ash, a fly ash generated from a stoker furnace at an incinerator for municipal waste is used. The fly ash is washed and desalted, and a fly ash having a water content of about 50% is received from a slurry supply port 9 and fed to a slurry tank. (1.0m × 2.6mΦ) 2. Then, the cycle of the rotating cart 3 of the slurry storage device 1 and the peripheral speed of the stirring blades 4a are variously changed, and the water content of the fly ash slurry (average water content in the slurry tank 2) is 45 to 46%.
After a lapse of one week while maintaining the pressure, it was tested whether or not it could be pumped by the piston pump from the outlet 10 of the bottom 2a.

First, the peripheral speed of the stirring blade 4a is set to 0.1
m / sec, and the cycle of the rotating car 3 is 5 minutes, 15 minutes,
The results were as shown in Table 1 when it was tested whether the pumping was possible by changing the pressure to 30 minutes, 1 hour, 2 hours, 3 hours, and 5 hours. In addition, the symbol described in the column of evaluation in the table,
“O” indicates that the pumping is possible, and “X” indicates that the pumping is impossible. From this result, it can be understood that sedimentation / separation of the fly ash slurry can be prevented by stirring once every three hours at the maximum. If the cycle of the rotary cart 3 is 5 hours, fly ash particles and water separate and settle, and the settled fly ash particles block the transportation pipe and cannot be pumped.

[0021]

[Table 1]

Further, as shown in Table 1, when the cycle of the rotary truck 3 is 3 hours or less, the settling and separation of the fly ash slurry can be prevented, and the pump can be pumped by a pump. If it falls below, the power of the rotating car 3 rises sharply. Therefore, it is preferable to set the cycle to 15 minutes or more.

Next, the cycle of the rotating carriage 3 is fixed to one hour, and the peripheral speed of the stirring blade 4a is set to 0.005 m / sec and 0.01 m.
/ M, 0.1 m / s, 1 m / s, 3 m / s, and 5 m / s were tested to see if they could be pumped by the pump. The symbols described in the column of evaluation in the table mean the same contents as in Table 1.

[0024]

[Table 2]

As shown in Table 2, when the peripheral speed of the stirring blade 4a is 0.01 m / sec or more, the sedimentation of fly ash slurry
Separation can be prevented, and pumping can be performed by a pump. However, if the peripheral speed exceeds 1 m / sec, the power of the stirrer 4 rises sharply. Therefore, the peripheral speed is set to 0.01 m / sec or more and 1 m / sec or less. It is suitable.

Further, the cycle of the rotating bogie is fixed at one hour, the peripheral speed of the stirring blade is fixed at 0.1 m / sec, and the bogie power and the bogie power are set at one week, one month, two months, and four months, respectively. The stirring power was measured to determine whether the slurry could be pumped. Table 3 shows the results. If the stirring period was within 4 months, there was no significant change in the truck power and the stirring power, and it was found that the slurry could be pumped without any problem.

[0027]

[Table 3]

It should be noted that, depending on the properties of the slurry and the storage period, it is possible to intermittently operate the rotary cart 3 or the stirring blades 4a, or both, so that the driving power can be further reduced.

[0029]

As described above, according to the present invention,
Fly ash slurry and the like can be stored for long-term pumpability while keeping operating power and equipment costs low.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a slurry storage device according to the present invention.

FIGS. 2A and 2B are views showing a stirring blade of the slurry storage device of FIG. 1, wherein FIG. 2A is a front view, FIG. 2B is a side view, and FIG.

[Description of Signs] 1 Slurry storage device 2 Slurry tank 2a Bottom 2b Side wall 3 Rotating cart 4 Stirrer 4a Stirrer blade 4b Rotating shaft 4c Flat steel 4d Horizontal member 5 Rotating shaft 6 Roof 8 Water supply pipe 9 Supply port 10 Discharge port

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Fukamachi 5378 Mikajiri, Kumagaya-shi, Saitama Pref. 3E070 AA02 AB04 FA08 RA01 VA05 WA05 4D059 AA30 BJ01 BK12 BK30 4G035 AB46 4G078 AA23 AB20 BA05 BA07 DA01 DB04

Claims (3)

[Claims] 1. A slurry is supplied into a cylindrical slurry tank having a circular portion as a bottom portion, and a rotary bogie extending from a rotary shaft installed at the center of the circular shape of the slurry tank in the outer peripheral direction of the circle is provided. Rotate at a cycle of not less than minutes and not more than 3 hours, and stirrers attached to one or more stirrers rotatably mounted in a planetary manner on the rotating carriage are 0.01 m
A method for storing a slurry, characterized in that the slurry is rotated at a peripheral speed of not less than 1 m / sec and not more than 1 m / sec. 2. The method for storing slurry according to claim 1, wherein the slurry to be stored is a slurry of fly ash generated from a municipal waste incineration plant. 3. A cylindrical slurry tank having a circular portion as a bottom portion, and a rotary bogie rotating around an axis of rotation provided at the center of the circular shape of the slurry tank and extending from the axis in the outer circumferential direction of the circle. A fly ash slurry storage device comprising: one or more stirrers attached to the rotating carriage so as to be rotatable in a planetary manner and provided with stirring blades rotating about a rotation axis.