JPS6311959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sludge drying device, and more particularly to a sludge drying device that is used in combination with a sewage sludge incinerator and is suitable for drying sludge with a high water content.

Directly transporting sewage sludge with a high moisture content (hereinafter referred to as wet sludge) into the incinerator reduces the operating efficiency of the incinerator and decreases the furnace efficiency, as it is necessary to dry the wet sludge in the incinerator. let For this reason, before sending the wet sludge to the incinerator, the wet sludge is dried using a drying device, and the dried sludge (hereinafter referred to as dried sludge) is sent to the incinerator.

Conventionally, a rotary dryer has been generally used as a dryer for turning the wet sludge into dry sludge, and the heating methods include a direct heating method in which flame is blown directly into the rotary cylinder, and a rotary dryer in which a flame is blown directly into the rotary cylinder. An indirect heating method is provided in which heating is performed from the outer periphery of the cylinder and the inside is heated through the body wall.

By the way, when dry sludge is passed through an incinerator and incinerated, if the shape of the sludge is not uniform, the combustion will not proceed uniformly. Dry sludge is discharged from the furnace with the central part unburned.Also, if the passage speed through the furnace is made small, even large lumps of dry sludge can be sufficiently burned to the central part. This has the disadvantage that the operating efficiency of the system decreases accordingly. Therefore, when converting wet sludge into dry sludge, it is desirable to convert the wet sludge into uniform granular dry sludge suitable for incineration.

However, in conventional drying equipment, the supplied sewage sludge is not uniformly heated and dried, and as a result, the sludge tends to adhere to the inner peripheral surface of the rotating drum, and the form of the dried sludge is , it is experienced that it is distributed over a wide range from large lumps to powders.

In addition, when conventionally known rotary dryers are used for drying sludge, direct heating systems generate bad odors and a large amount of exhaust gas, which poses problems in exhaust gas treatment. The problem with indirect heating systems that heat from the outer periphery is that they have low thermal efficiency and therefore require a large amount of heat.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sludge drying apparatus that converts sewage sludge with a high water content into uniformly granular dried sludge suitable for incineration.

Another object of the present invention is to provide a sludge drying device that suppresses the generation of foul-smelling exhaust gas and has high thermal efficiency.

Examples of the present invention will be described.

The sludge drying device A has a main body 1 that surrounds a rotary drum 2 that is inclined downward toward its outlet and defines a space B therein through which heated gas passes. The main body 1 has an inlet 7 for introducing high-temperature waste gas from an incinerator (not shown) into a space B, an outlet 8 for discharging gas in the space B, and a rotating blower 15 for rotating the high-temperature waste gas in the space B. It has a hot air inlet 16 for feeding into the shell 2.

An inlet hood 5 is provided at the inlet of the rotating body 2,
A screw feeder 9 is extended through the hood 5 to the inlet of the rotary drum 2, allowing sewage sludge to be carried into the rotary drum 2.

An outlet hood 6 is provided at the outlet of the rotary barrel 2,
In addition, the outlet hood 6 is provided with an exhaust fan 17, and the dry waste gas from the rotary cylinder 2 is sent to the incinerator through the gas outlet 18, so that malodorous components are treated in the incinerator. Further, the outlet hood 6 is provided with a screw feeder 21 for taking out the dried sludge, thereby making it possible to transport the dried sludge to the incinerator.

The rotary drum 2 is provided with a rotary tire 4, and the rotary drum 2 is rotatably supported by a side roller 19 facing the rotary drum 2. Furthermore, a drive gear 3 is fixed to the rotary drum 2, and a drive motor 21 drives the rotary drum 2. allows for rotation.

In the above-mentioned configuration, the high-temperature waste gas that enters the space from the inlet 7 indirectly dries the sewage sludge inside the rotary cylinder 2 through the outer wall of the rotary cylinder 2 for heat exchange, and a part of the high-temperature waste gas enters the space through the inlet. 16 into the rotating drum 2, it prevents the adhesion of sludge, prevents the condensation of dry steam, and has a heating effect by heat radiation, thereby drying the sewage sludge inside the rotating drum 2. Furthermore, depending on the required drying state and granulation state, the hot air volume adjustment damper 2
2 and 23 to adjust the amount of hot air blown into the rotating body 2.

In this way, since the rotary drum 2 is heated from its outer surface and at the same time directly heated from the inside, the sludge inside the rotary drum 2 is uniformly dried and the sludge is prevented from adhering to the rotary drum. In addition, it has high thermal efficiency because it uses high-temperature waste gas from the incinerator.

Next, the internal structure of the rotating drum 2 will be described with reference to FIG. At the inlet of the rotating body 2, there is a fast-forwarding lifter 10 and a chain 1 fixed to the lifter 10.
1 is placed and constitutes the (a) zone. (a) The zone is
It functions to prevent sewage sludge from accumulating at the point where it falls from the feeder 9 into the rotary drum 2. An angled lifter 12 is provided in the next zone (b). The lifter 12 has a high lifting capacity. Shown in Figure 2
A flat lifter 13 with a small raking capacity is provided from zone (c) to zone (g), and a weir 14 is further provided at a suitable location at the outlet of this zone. Also, preferably,
From zone (c) to zone (e), a weir 14 is provided at an intermediate position between the inlet and outlet of the flat lifter 13. An angled lifter 12 with a large raking capacity similar to the zone (b) is provided in zone (h) at the outlet of the rotary cylinder 2. The lifter 12 is a plate-shaped body fixed to the inner wall of the rotating barrel along the longitudinal direction of the rotating barrel 2 or at an appropriate inclination angle with respect to the axial direction, and its tip is fixed to the inner wall of the rotating barrel 2. is bent in the direction of rotation. The lifter 12 may be arranged perpendicularly to the tangent to the inner wall of the rotating body 2, or may be fixed at an appropriate angle. number of lifters 12,
The height and shape are appropriately selected according to the characteristics of the sludge.
The flat lifter 13 is a plate-shaped body that extends along the axial direction of the rotating body 2 and extends from the inner wall of the rotating body in the axial direction, and its height, length, shape, interval, number, etc. shall be selected appropriately depending on the properties of the sludge.

The weirs 14 are arranged approximately at right angles to the lifters so as to connect adjacent lifters 13, and are shifted back and forth so that the weirs 14 do not overlap directly and form a passage between them, or the weirs 14
A plurality of pieces are fixed to the inner wall of the rotating drum 2 so as to leave a space inside. The weir 14 is fixed to the inner wall of the rotary shell 2 and the lifter 13 so as to stand substantially upright from the inner wall of the rotary shell 2. 14 has notch 2
4 will be provided. The height of the weir 14, the size of the passage 25,
Alternatively, the spaces between the weirs 14, etc. are determined according to the properties of the sludge. The weir 14 has the effect of moving only the dried sludge granulated to a certain size toward the outlet, lengthening the residence time of the sludge in the rotating drum 2, and increasing the heat transfer area. In addition, the passage 25 and the weir 1
It is preferable that the size of the space between the zones 4 and 4 is gradually narrowed in accordance with the average granulation state of each zone. In addition,
A plurality of holes may be provided in the weir 14 to form the passage 25.

In the example described above, high-temperature waste gas from the incinerator is sent to the space B from the inlet 7, and a part of it is sent to the inlet 1.
6 into the rotary cylinder 2 to heat the rotary cylinder 2 from the outside and inside. Sewage sludge is carried into the rotating drum 2 from the screw feeder 9. Further, the rotating drum 2 is rotated via a motor 20 and a gear 3. The sludge in the rotating drum 2 is removed by a lifter 12,
13. After being stirred and granulated by a weir 14 and dried, it is sent to an incinerator via a feeder 21. The waste gas in the rotating barrel 2 is sent to the incinerator through the outlet 18. Note that although the gas in space B is exhausted from the outlet 8, it can be returned to the incinerator again, heated, and then fed into space B together with the high-temperature waste gas.

In addition, as a result of drying sewage sludge (using a polymer flocculant) with a water content of 75 to 85%, which had a significant volume reduction, to a water content of approximately 50% or less using the drying equipment described above,
Uniform dry granules of ~20φ were obtained, and approximately 75%
When lime-filled sewage sludge with a moisture content of 50% or less was dried to a moisture content of about 50% or less, dried granules with a diameter of about 5 to 10 φ were obtained.

As is clear from the above, by combining a lifter and a weir inside the rotating barrel and heating the rotating barrel from the outside and the inside, the sludge inside the rotating barrel can be effectively heated and the sludge can be stirred and created. The granulation is effectively achieved and dry sludge granules suitable for incineration can be obtained. This also has the effect of making it possible to reduce the hearth area and fuel of the incinerator.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the drying device, FIG. 2 is a view showing the inside of a rotary drum, FIG. 3 is a sectional view showing an example of a lifter, and FIG. 4 is a sectional view showing an example of a weir. In the diagram: 2... Rotating cylinder, 7... High temperature waste gas inlet,
8...Exit, 9...Feeder, 10,12,1
3...Lifter, 14...Weir, 16...Gas inlet.

Claims (1)

[Scope of Claims] 1. A rotary drum, a power device that rotates the rotary drum, a heating device that heats the outside and inside of the rotary drum, and a conveyance device that feeds sludge into the rotary drum. A sludge drying apparatus characterized in that a weir is provided inside the rotary drum and is connected to a lifter spaced apart and forms a sludge passage. 2. The sludge drying device according to item 1, wherein the lifter is a plate-shaped body extending in the axial direction of the rotary drum, and the weir is fixed at a substantially right angle to the lifter. drying equipment. 3. The sludge drying device according to item 2, wherein a notch is provided in the weir to form a passage between the weir and the inner wall surface of the rotating drum. 4. In the apparatus of paragraph 1, the heating device surrounds the outer wall of the rotary shell and includes a space into which high-temperature waste gas from the incinerator is introduced, and a passage device that communicates the space with the inlet of the rotary shell. A sludge drying device characterized by: