JP4559678B2 - Sludge carbonization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention utilizes the Rotariki Le down, the sludge wastes such as sewage sludge, it relates to a method for carbonizing extremely energy-saving manner yet continuously.
[0002]
[Prior art]
In general, a rotary kiln is designed to inject a flame from the lower side into the inside of the cylinder while rotating the cylinder with a fire resistant inner surface slightly inclined from the horizontal, while the cement material from the upper side. It is known as a material for feeding raw materials such as the above and firing the raw materials.
[0003]
Recently, although techniques for processing combustible wastes using the above Rotariki Le emissions have been proposed, in the proposed method high viscous water content is high yet irregular, such as sewage sludge The object can hardly be carbonized efficiently. In addition, in the case of processing irregular shaped waste such as sewage sludge, the flame that blows into the inside from the lower side of the rotary kiln is still blown during the treatment. There is a drawback that the fuel cost increases significantly.
[0004]
[Problems to be solved by the invention]
Accordingly, the present invention provides a method for treating sludge and the like that not only can continuously carbonize an object having a high moisture content, such as sewage sludge, but has an irregular shape and high viscosity, and also significantly suppresses fuel consumption in the treatment. Is the subject.
[0005]
[Means for Solving the Problems]
The structure of the method of the present invention made for the purpose of solving the above problems is as follows: (a) a cylinder in which a spiral conveying wall is formed on the inner peripheral surface and a stirring wall is formed in a part of the conveying wall to cross the conveying wall. to Jo rotary kiln, wherein while providing rotation of the feed direction of the conveyor walls, preheating the interior by blowing the flame from the burner, (ii) after performing the pre-heating, pre-processing unit the amorphous sludge containing water The sludge that has been shaped in the molding part and the surface sludge that has been shaped in the molding part in the surface drying part are brought into a surface state in which they do not adhere to or adhere to each other. The rotary kiln is continuously supplied in a predetermined unit amount while rotating the rotary kiln. (C) Flame is introduced into the rotary kiln from below the rotary kiln in the state (b). Infuse When the gas component released from the sludge is ignited in the rotary kiln, the blowing of the flame is stopped. (D) The gas inside the rotary kiln from above the rotary kiln in the state of (b) and (c) (E) The stirring wall in (a) bulges inward from the outer peripheral edge of the transfer wall, and is formed to be lower than the height of the transfer wall. By performing the operations (a) to (e) above, the agitation is performed so that the sludge does not enter the inner peripheral edge of the conveyance wall and the front and back of the conveyance wall are reversed and rolled. The sludge carbide is discharged from the lower part of the rotary kiln.
[0006]
In the present invention, in order to obtain a surface state in which each sludge that has been shaped does not adhere or stick to each other, for example, the surface may be substantially dried by using appropriate heating means, blowing means, or heated blowing means. it can.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the method of the present invention will be described with reference to the drawings. FIG. 1 is a side view schematically showing a part of a carbonization apparatus for carrying out the method of the present invention. FIG. 2 is a cross-sectional side view of the carbonization apparatus shown in FIG. FIG. 3 is a partially enlarged perspective view of a conveying wall provided with different stirring walls, and FIG. 3 is a cross-sectional view of a cylindrical body 1 showing a state in which carbonization is performed by the apparatus shown in FIG. 1 using the conveying wall shown in FIG. 4 and 4 are sectional views of the cylindrical body 1 showing a state in which the cylindrical body 1 is rotated from the state shown in FIG.
[0008]
In the figure, 1 is a steel tube cylinder having a length of about 10 m and an inner diameter of about 40 to 50 cm. Here, a plurality of required unit length cylinders are connected to each other by joints having an outer flange shape. A single cylinder 1 is formed.
[0009]
2 is a transport wall provided on the inner surface of the cylindrical body 1 so as to form a spiral over the entire length of the cylindrical body 1, and the front side (left side in the figure) of the entire length of the cylindrical body 1 A stirring wall 3 is provided in a direction crossing the conveying path formed by the spiral conveying wall 2.
[0010]
Reference numeral 4 denotes a heat insulating layer provided on the entire outer surface of the cylindrical body 1, and the rotary kiln main body Kb is formed by the configuration from the cylindrical body 1 to the heat insulating layer 4 described above.
[0011]
The rotary kiln main body Kb is provided with belt-like rings 5 at three positions in the length direction, specifically, at both front and rear ends and a central portion, and support rollers 6 and 7 that are rotatable around the lower portions of the rings 5. , 8 and rotating at least one of the rollers as a driving roller by a motor or the like, the rotary kiln body Kb rotates at a fixed position on the rollers 6-8. In addition, 6a, 7a, 8a is a roller frame, and BF is a base frame in which the roller frames 6a to 8a are fixed. In the illustrated example, the rotary kiln main body Kb is provided in a substantially horizontal posture, but may be arranged with a downward slope (the right side in the figure is downward).
[0012]
Reference numeral 9 denotes a flame gas burner disposed on the lower side (right side in the figure) of the rotary kiln main body Kb, and the flame injection port 9a of the burner 9 is provided toward the inner side of the main body Kb. In addition, it forms in the pit P which arrange | positions the container 20 which accommodates a carbonization processed material in front of the gas burner 9. FIG.
[0013]
10 is an input means for processing disposed on the upper side of the rotary kiln main body Kb. Specifically, it is formed by a conveyor, a hopper with a shutter or the like, such as sewage sludge to be processed inside the rotary kiln main body Kb. The waste is formed so as to be continuously supplied at a unit amount / hour.
[0014]
Reference numeral 11 denotes a pretreatment unit disposed on the front side of the charging means 10, and the pretreatment unit 11 includes a molding unit 11a and a surface drying unit 11b. In this molding part 11a, when the object to be treated is sewage sludge, although not shown, a mixer for kneading ore powder into the sludge and a function for continuously discharging the kneaded material from the mixer from the discharge nozzle are provided. For example, it is formed by a pellet molding machine. Further, the pre-processing unit 11 is selectively or in parallel arranged above the rotary kiln main body Kb. In the surface drying section 11b of the pretreatment section 11, the sludge molded and shaped by the molding section 11a is received, and the surface of the sludge is dried by the heating means or the blowing means or by the heating blowing means. As such means, for example, a drum dryer is used, but other heating and blowing devices can be used as long as they have similar functions. The sludge whose surface has been dried in the surface drying section 11b is conveyed to the input means 10 by a belt conveyor. The surface of each sludge thus shaped is dried so that the sludge adheres and adheres to each other when the sludge is thrown into the charging means 10 or when it is transported inside the rotary kiln body Kb. If there is a method in which each sludge does not adhere or adhere to the surface other than drying the surface, the method can naturally be used.
[0015]
Reference numeral 12 denotes exhaust processing means for sucking and detoxifying the gas present in the kiln during the processing process at the upper open end of the rotary kiln main body Kb, and is schematically shown as a block in the drawing. Of these, 12a is a combustion block by an afterburner and a combustion chamber for burning and processing black smoke, bad odor and bad odor that may be generated depending on the object to be treated, 12b is a cooling block for cooling the exhaust gas coming out of this combustion block 12a, 12c is The neutralization block is filled with slaked lime for neutralizing Cl components in the cooled exhaust and activated carbon for increasing the dust collection efficiency of the filter cloth in the next filter block. A pulverized carbonized sludge coal can be used. 12d is a filtration suction block comprising a filter block for filtering ash and dust in the exhaust and a suction block such as a cyclone as a cooling means.
[0016]
Since an example of the carbonization processing apparatus using the rotary kiln for carrying out the method of the present invention is constructed as described above, the carbonization treatment of sludge using this apparatus will be described next.
[0017]
First, in the pretreatment unit 11, the dehydrated sewage sludge to be treated is mixed with ore powder at a ratio of about 3 to 8% by volume, and the whole is kneaded to reduce the moisture content of the sludge, similar to the kneaded one. In addition, it is supplied to the charging means 10 by being extruded from a molding machine.
[0018]
On the other hand, for the rotary kiln main body Kb, by rotating the driving roller among the rollers 6, 7, and 8 prior to the input by the input means 10 to be processed, the kiln main body Kb is moved by the conveying wall 2. While giving rotation in the feed direction, a flame is blown from the burner 9 to preheat the inside. This preheating is performed for about 20 minutes, and the processing object (sludge) is continuously supplied from the charging unit 10 to the upper side of the rotary kiln main body Kb while the flame is being blown.
[0019]
The introduced sludge is sequentially sent to the lower side of the kiln main body Kb by the action of the internal transfer wall 2 by the rotation of the rotary kiln main body Kb. In this feeding, in the portion where the stirring wall 3 is provided, the action of this wall 3 repeats the behavior of sludge being lifted and dropped to the ceiling side of the kiln main body Kb, thereby promoting drying. In addition, since the flame is blown from the burner 9 into the kiln main body Kb at the time of feeding, the water in the sludge evaporates and the moisture content of the sludge itself increases as it goes downstream of the rotary kiln main body Kb. Almost disappear. Further, the exhaust treatment means 12 is already driven at this stage and sucks the inside of the rotary kiln main body Kb.
[0020]
As a result, the combustible gas component that is introduced into the rotary kiln main body Kb, transported to the lower side by the rotation of the main body Kb, and reaches the lower end of the dried sludge is discharged from the inside. Ignite by. In the present invention, when the sludge ignites the gas component in this way, the blowing of flame from the burner 9 is stopped. Although the combustion state of the gas component does not change even when the blowing of flame is stopped, the ignition part gradually moves up the inside of the rotary kiln main body Kb (the processing material input side), for example, the upper end Localization (combustion position F) is performed at a location of about 2 to 3 m from the section, and combustion of combustible gas components released from the sludge continues there. The internal temperature of the rotary kiln main body Kb at this time is about 800 ° C to 830 ° C.
[0021]
In the rotary kiln main body Kb as described above, combustible gas components released from the sludge are combusted. The carbonization mechanism of the sludge by this combustion will be described. It is combustion of the combustible gas discharged | emitted from the inside of the processed material M that the processed material M (sludge) seems to burn at the fixed position F in the rotary kiln main body Kb. And this combustion is maintained at the fixed position F because the sludge as the processed material that is sequentially sent from above to the fixed position F by the rotation of the rotary kiln main body Kb is just inside the rotary kiln main body Kb. This is because the combustion condition of the combustible gas discharged from the sludge inside is adjusted at the position F. That is, the oxygen necessary for the combustion of the combustible gas is always supplied from the lower side (downstream) of the rotary kiln main body Kb (the suction action of the exhaust processing means 12), but the supplied oxygen is almost at a fixed position F. combustion will be consumed in, the Rotariki Le emissions body Kb in because oxygen for the sludge itself is burned depleted.
[0022]
As a result, in the rotary kiln main body Kb, the combustible gas continues to burn at the fixed position F, and the inside of the kiln main body Kb is subjected to the suction action of the exhaust processing means 12, so that the combustion position F The upstream side is almost oxygen-free or oxygen-deficient, and the oxygen sucked also on the downstream side is consumed for combustion at the fixed position F to be oxygen-deficient or its approximate state. On the other hand, with the combustion maintained at the fixed position F as a heat source, the inside of the rotary kiln main body Kb is maintained at about 800 ° C. to 830 ° C. except for the lower end (outside air inflow end). The treated material M (sludge) conveyed inside the rotary kiln main body Kb in such an oxygen environment and temperature environment is thermally decomposed without being burned and carbonization proceeds. Since the carbonized sludge falls from the lower end of the rotating rotary kiln main body Kb into the container 20 of the pit P, the carbide is recovered there.
[0023]
In the case of sewage sludge, the moisture content fluctuates by about 10% depending on the season, so even if the sludge is shaped in the pretreatment section 11 and the surface is dried, the moisture content inside the sludge is seasonal. It depends on. However, since conditions are set so as not to adhere and stick to each other, even if the moisture content changes, the carbonization treatment is similarly performed in the rotary kiln main body Kb. That is, when the moisture content is low, the fixed position F where the combustion conditions in the rotary kiln main body Kb are adjusted moves upstream (the flame moves upstream), and when the moisture content is high, drying time is required. The fixed position F where the conditions are met moves downstream (flame moves downstream). This means that the discharge position of the combustible gas component discharged from the inside after the sludge is dried is automatically moved upstream or downstream in the rotary kiln main body Kb depending on the moisture content.
[0024]
Gas combustion inside the rotary kiln main body Kb and exhaust of the gas in the main body Kb caused by the carbonization phenomenon are sucked into the exhaust processing means 12, and black smoke and odor are processed by the combustion block 12a. In addition, the Cl component and the like pass through the cooling block 12b, and after being purified by the next neutralization block 12c, are released from the filtration suction block 12d to the outside of the system.
[0025]
Next, an agitating wall 31 as shown in FIG. 2 is provided on the transfer wall 2 in the cylinder 1 of the rotary kiln main body Kb of the carbonizing apparatus shown in FIG. An example will be described. The agitation wall 31 has a substantially semicircular cross-sectional shape bulging inward from the outer peripheral edge of the transfer wall 2, and according to this agitation wall 31, the processed material M enters the inner side of the inner peripheral edge of the transfer wall 2. There is not, and since it agitates so that the front and back of the processed material M may be reversed and rolled between the front and rear conveying walls 2 and 2, it is suitably carbonized without burning. That is, the heated hot air passes through the inside of the inner peripheral edge of the conveying wall 2 in the cylindrical body 1, but if the processed material M enters inside the inner peripheral edge, a direct flame is applied, so that ore is applied to the processed material M in advance. If not mixed, it will burn and a considerable amount will be incinerated. Therefore, if the processed material M is between the front and rear transfer walls 2 and 2 as described above and stirred (see FIGS. 3 and 4) so as not to enter the inner peripheral edge of the transfer wall 2, it will burn. In addition, oxygen between the front and rear transfer walls 2 and 2 is consumed for the combustion of the combustible gas discharged from the processed material M, so that there is very little oxygen between the transfer walls 2 and 2. In this state, when heated to a high temperature by the heated hot air passing through the inner side of the inner peripheral edge of the transfer wall 2, further combustible gas is generated from the processed material M, and a so-called steamed state is formed to promote carbonization. . Therefore, when this stirring wall 31 is used, it is not necessary to previously mix the ore with the processed material M, so that a highly pure carbide can be obtained. The shape of the agitation wall 31 is substantially semicircular in cross section. However, if the processed material M can be agitated in the same manner as described above, the agitation wall 31 may have a substantially triangular cross section, a substantially trapezoidal cross section, and a substantially mountain cross section. In addition, the outer surfaces of the stirring walls including the stirring wall having a substantially semicircular arc shape in cross section may be formed in a concavo-convex surface such as a waveform. In addition to the carbonization processing apparatus of this example, the carbonization processing apparatus shown in FIG. 1 also requires that the processed matter M such as sludge be prepared in order to obtain uniform charcoal. .
[0026]
【The invention's effect】
The present invention is as described above, and waste ( sludge ) that has not been considered in the past such as carbonization such as sludge having a high moisture content such as sludge and having an irregular shape and high viscosity is formed in the pretreatment section. The sludge that has been shaped at the part and formed into a surface state in which the sludge that has been shaped at the molding part in the surface drying part does not adhere or stick to each other, and then the shaped sludge is spirally formed on the inner peripheral surface. The inside of the cylindrical rotary kiln formed with a part of the conveying wall and the stirring wall crossing the conveying wall, the stirring wall bulging inward from the outer peripheral edge of the conveying wall and lower than the height of the conveying wall after preheating the, while rotating the person the rotary kiln above the rotary kiln was continuously fed at a predetermined unit amount, at the time of the supply, blowing a flame from below the rotary kiln into the interior of the rotary kiln, the Rotor When the gas component released from the waste (sludge) in the kiln is ignited, the blowing of the flame is stopped, the gas inside the rotary kiln is sucked from the upper side of the rotary kiln, detoxified and exhausted, and The agitation wall is used to agitate the sludge so that the sludge does not enter the inner peripheral edge of the conveyance wall and the front and back of the conveyance wall are reversed and rolled. Therefore, it is possible to continuously take out the waste such as sludge and to carry out the carbonization process efficiently and efficiently in an energy saving manner. Thus, the method of the present invention is extremely useful as a method for treating sewage sludge, which is particularly difficult for final treatment.
[0027]
In addition, according to the carbonization treatment method of the present invention, oxygen consumption is small because of the self-combustion method, compared to the conventional method of making sludge and the like a dehydrated cake having a water content of about 70 to 80% and incineration in an incinerator. Therefore, the effect that the emission of CO _{2 into} the atmosphere can be reduced by 35% is obtained. This means that the amount of air used for combustion can be reduced. Therefore, the combustion block for combustion can be reduced in size, and the cooling block, neutralization block, and filtration suction block can also be reduced in size. The effect of being able to be obtained.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a carbonization apparatus for carrying out the method of the present invention, partly in cross section.
2 is a partially enlarged perspective view of a transfer wall in which a stirring wall different from that in FIG. 1 is provided on the transfer wall in the carbonization apparatus shown in FIG.
3 is a cross-sectional view of a cylindrical body 1 showing a state in which carbonization is performed by the apparatus shown in FIG. 1 using the transfer wall shown in FIG.
4 is a cross-sectional view of the cylinder 1 showing a state in which the cylinder 1 is rotated from the state shown in FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Conveying wall 3 Stirring wall 4 Heat insulation layer 5 Band-shaped ring 6, 7, 8 Support roller 9 Gas burner
9a Flame outlet
10 Input means
11 Pre-processing section
11a Molding part
11b Surface drying section
12 Exhaust treatment means
12a combustion block
12b cooling block
12c Neutralization block
12d filtration suction block
Kb Rotary kiln body M Carbonized material

Claims (3)

(A) A cylindrical rotary kiln having an inner peripheral surface formed with a spiral conveying wall and a stirring wall that crosses the conveying wall in a part of the conveying wall is rotated in the feeding direction by the conveying wall, Preheat the inside by blowing flame from the burner,
(B) After preheating, the amorphous sludge containing moisture is shaped in the molding part in the pre-treatment part and the sludges shaped in the molding part in the surface drying part are bonded to each other. After making the surface state not sticky, the shaped sludge is continuously supplied above the rotary kiln in (a) in a predetermined unit amount while rotating the rotary kiln.
(C) A flame is blown into the rotary kiln from below the rotary kiln in the state (b), and a flame is blown when a gas component released from the sludge is ignited in the rotary kiln. Stop
(D) The gas inside the rotary kiln is sucked from the upper side of the rotary kiln placed in the states (b) and (c), detoxified, and exhausted.
(E) The stirring wall in (a) bulges inward from the outer peripheral edge of the transfer wall and is formed to be lower than the height of the transfer wall, and the sludge is inside the inner peripheral edge of the transfer wall by the stirring wall. Stir so that the front and back are inverted and rolled between the front and rear transfer walls without entering.
(F) A method for carbonizing sludge, characterized in that the sludge carbides are discharged from the lower part of a rotary kiln by performing the operations (a) to (e).   2. The sludge carbonization method according to claim 1, wherein the sludge that has been shaped is brought into a surface state in which the sludges are not bonded or adhered to each other using a heating means, a blowing means, or a heating blowing means.   The method of carbonizing sludge according to claim 1 or 2, wherein the shape of the stirring wall is any one of a substantially semicircular cross section, a substantially triangular shape, a substantially trapezoidal cross section, a substantially mountain-shaped cross section, and an outer surface uneven shape.

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