JPS6344659Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a sludge incineration system, and more specifically, to a sludge incineration system in which sludge is dried using a screw-type rotary dryer and then sent to an incinerator for incineration, in which the sludge can be dried efficiently in the rotary dryer section by using the heat generated in the incinerator.

Incineration is one of the post-treatment methods for sludge discharged from various wastewater treatment facilities. This method is a method in which combustible materials are incinerated after drying the sludge to remove moisture, and unlike methods in which sludge is solidified with cement, a solidifying agent is not required and post-treatment operations are relatively simple. Moreover, since most of the waste is burned down, it has various advantages, such as the amount of final waste being drastically reduced. On the other hand, in order to incinerate sludge with a high water content, it is necessary to dry the sludge to remove water, which requires a large amount of energy.To reduce this burden, the following equipment is available. was developed.

That is, Fig. 1 shows a device that continuously dries and burns sludge, and Fig. 2 shows a cross-sectional view taken along the line - - in Fig. 1. are installed in series to transfer sludge A from the sludge hopper 3 to the rotary dryer 2.
supply. The rotary dryer 2 is configured so that the incinerator exhaust gas passes through the sludge feeding atmosphere, and the sludge A transferred toward the top of the incinerator 1 by the dryer 2 is dried by the exhaust gas heat. , are sequentially supplied to the incinerator 1. In the figure, 4 is a combustion burner, 5 is a fire grate, 6 is a rotary rotor for removing ash, 7 is a combustion air supply duct, 8 is a flue,
9 indicates a sludge guide wall.

With this type of equipment, the combustion heat of dried sludge can be used to dry the subsequently supplied water-containing sludge, so it is extremely economical as it does not require special energy to dry the sludge. Conceivable.
However, in reality, exhaust gas heat is not efficiently utilized for drying sludge, and it is often experienced that poor combustion occurs within the incinerator 1. The biggest reason for this is that the moisture content of sludge is generally extremely high (approximately 60 to 90% or more) and requires a large amount of thermal energy to dry. One problem is that exhaust gas heat is difficult to transfer to the sludge inside because it only passes through the upper part. Therefore, in order to solve the above-mentioned difficulties, the rotary dryer 2 should be made longer to increase the contact time between the sludge and the exhaust gas, or the sludge should be pre-dehydrated or pre-dried before being fed to the rotary dryer. However, with the former method, the drying section becomes long, which increases equipment and maintenance costs, and with the latter method, a separate pre-drying device must be installed, which increases equipment costs. At the same time, the processing process also becomes complicated.

The inventor focused on the above-mentioned circumstances, and the first and second
In the sludge incinerator shown in the figure, the heat retained in the combustion exhaust gas is utilized as effectively as possible to efficiently dry the sludge in the screw-type rotary dryer section, thereby preventing problems such as poor combustion. I have been conducting research. The present invention was completed as a result of such research, and its configuration consists of a sludge incinerator and a screw-type rotary dryer for supplying sludge to the upper supply section of the incinerator. The gist lies in that the drive shaft of the rotary dryer is constituted by a heat pipe, and the heat pipe is arranged on the sludge guide wall on the outer peripheral side of the dryer along the direction of movement of the sludge.

The configuration and effects of the present invention will be explained below based on drawings showing embodiments, but the drawings are representative examples and are not intended to limit the invention. All changes to the shape, structure, etc. of the incinerator or screw-type rotary dryer are included in the scope of the present invention.

Fig. 3 is a schematic cross-sectional explanatory diagram illustrating the sludge incinerator according to the present invention, and Fig. 4 is a cross-sectional view corresponding to the - line in Fig. 3, and the basic configuration is the same as the example in Figs. 1 and 2. Therefore, the same parts are given the same reference numerals. However, in the present invention, the drive shaft 2a of the screw constituting the rotary dryer 2 is constructed with a heat pipe, and a heat pipe 10 is arranged on the sludge guide wall 9 on the outer peripheral side of the dryer 2 along the sludge transfer direction. , its tip protrudes into the exhaust gas flow path of the incinerator 1. As a result, exhaust gas heat is transferred to the rotary dryer 2 through the screw drive shaft 2a and the heat pipe installed on the sludge guide wall.
The sludge A is heated from the inside. Furthermore, since the sludge transferred through the upper part of the dryer 2 is heated by direct contact with the exhaust gas as in the conventional example, the present invention can further heat the sludge by the amount of heat transferred by the heat pipe, and the relatively short rotary Even when a dryer is used, the sludge can be sufficiently dried. Moreover, in the conventional method, only the heat of the contact part of the exhaust gas with the surface layer of sludge is effectively used for drying, and most of the heat of the exhaust gas escapes directly to the flue 8 direction. This system uses heat from other exhaust gases to heat the internal sludge while retaining heating, and can greatly increase efficiency in terms of effective use of thermal energy.

Thus, the greatest feature of this device is that it utilizes a heat pipe to transfer heat from the exhaust gas to the inside of the rotary dryer, accelerating the drying of the sludge, and as long as this feature can be effectively utilized, various modifications other than those shown in the figures are possible. For example, as a method of providing a heat pipe on the screw shaft of a rotary dryer, in addition to constructing the shaft itself as a heat pipe, covering the outer periphery of the shaft with a number of small diameter heat pipes will show even higher heat transfer efficiency (i.e. drying efficiency), and if the heat pipe is extended to the screw flight, the drying efficiency will be further improved. Also, the heat pipe to be installed on the sludge guide wall may be exposed to the guide wall if it is of high physical strength, but
The preferred method is to embed the heat pipe in a wall made of a heat transfer material, which can suppress wear and damage to the heat pipe itself caused by resistance during sludge transport. Furthermore, the type of incinerator 1 connected below the rotary dryer is not limited at all, and it can be a forced transport type using a moving grate or a fixed grate type, etc., as long as it can efficiently incinerate the pre-dried sludge, and can be selected appropriately depending on the type of sludge and the amount of processing, etc., and all of these changes are within the scope of the technology of this invention.

The present invention is constructed as outlined above, and by making the most effective use of the heat of combustion exhaust gas, it is possible to efficiently dry sludge during transfer to a screw-type rotary dryer. This prevents poor combustion, etc., and enables a series of processes from drying sludge to incineration to be carried out efficiently and smoothly.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional explanatory diagram showing a conventional sludge incinerator, Fig. 2 is a cross-sectional view corresponding to the - line in Fig. 1, Fig. 3 is a schematic cross-sectional explanatory diagram showing an embodiment of the present invention, and Fig. 4 is a schematic cross-sectional explanatory diagram showing a conventional sludge incinerator. It is a cross-sectional view corresponding to the - line in FIG. 3. 1...Incinerator, 2...Rotary dryer,
3...Sludge supply hopper, 4...Combustion burner,
5...Grate, 6...Rotary roaster, 7...
...Combustion air duct, 8... Flue, 9... Sludge guide wall.

Claims (1)

[Scope of utility model registration request] A sludge incinerator and a screw-type rotary dryer for supplying sludge to the upper part of the incinerator are assembled together, and the drive shaft of the rotary dryer is composed of a heat pipe, and the sludge on the outer periphery of the dryer is A sludge incinerator characterized in that a heat pipe is arranged on a guide wall along the direction of movement of sludge.