JPS59166300A - Sludge drying incinerator - Google Patents

Abstract

PURPOSE:To prevent decrease in the coefft. of heat transmission by heating the steam generated from a drying chamber by waste combustion gas in a heat exchanger, connecting the other end of the heat exchanger to the heating chamber and drying chamber of a dryer and drying sludge with the heating steam. CONSTITUTION:Water-contg. sludge is charged as shown by an arrow (a) into a sludge feeder 5, by which the sludge is fed into a drying chamber 3 and while the sludge is moved by a conveyor 7 from the inlet to the outlet of the chamber 3, the sludge is heated by the heat from a heating chamber 4 and is discharged like an arrow (b). The dry sludge discharged from said chamber is charged into an incineration furnace B and is incinerated. The waste combustion gas generated from said furnace is introduced through a discharge pipe 23 indicated by arrows (f), (g), (h) into a heat exchanger C, from which the gas is discharged to the atmosphere. The steam generated from the sludge in the chamber 3 is fed by a blower 9 to the heat exchanger C and is heated to a supersatd. state by the heat exchanger. The heated steam is fed into the chamber 4 and the chamber 3 and the heat is radiated therefrom via an inside cylinder 2, by which the sludge is heated and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drying and incineration device for sludge generated in water treatment equipment.

Generally, the purpose of sludge treatment is to stabilize sludge under natural conditions and reduce its volume, but if it is incinerated, most of the organic matter in sludge will be burned and become carbon dioxide and water vapor, which can be released into the outside air. The remaining ash is hygienic, safe, and harmless as long as it does not contain harmful metals such as Cd, and is therefore easy to dispose of.

Therefore, incineration of sludge can be said to be a very preferable treatment method.

By the way, sludge generated in water treatment systems is usually subjected to concentration treatment using a thickening sedimentation tank and mechanical dehydration treatment using a centrifuge, but even in this case, the water content of the sludge is 80%.
Since the moisture content decreases only to about 85% and it is difficult to directly incinerate it as it is, it is necessary to dry it until the moisture content reaches 30 to 50%, and an indirect drying method is generally adopted.

However, although this method has the advantage that the hot air for drying is not contaminated with sludge, it has the disadvantage of high heat transfer resistance. For this reason, steam is usually used as the hot air source,
The heat transfer coefficient is increased by condensing heat transfer.

In this indirect drying method using steam as a heat source, the generated steam and high-moisture sludge coexist in the drying chamber, and the generated steam is usually saturated or supersaturated. . For this reason, once evaporated water condenses with a slight drop in temperature. Therefore, on the transport path from the dryer to the incinerator, a phenomenon occurs in which water vapor comes into contact with the wall surface, causes the temperature to drop, condenses, and is reabsorbed into the dried sludge. As a means to prevent this condensation phenomenon, a method is usually adopted in which high-temperature air called carrier air is blown into the drying chamber to create an unsaturated state. The amount is approximately 0.7 to o in absolute temperature,
It must be adjusted to the extent that s (Ky/Kp! air).

On the other hand, from the viewpoint of energy saving, in the drying and incineration process of sludge, the water vapor generated from the drying chamber of the dryer is sent through a heat exchanger and heated by the sludge combustion exhaust gas, and then the steam is transferred to the heating chamber of the dryer. The sludge is dried.

When the carrier air is applied to such a method,
A large amount of air will be mixed into the water vapor generated in the drying chamber, and the water vapor at this air temperature will be used again as a heating source for drying. According to the known heat transfer theory, This has the disadvantage that the heat transfer coefficient is significantly reduced and the original heat transfer characteristics of water vapor are lost.

The present invention takes the above points into consideration and aims to supply superheated steam not only to the heating chamber but also to the drying chamber to prevent a decrease in the heat transfer coefficient.

That is, the drying and incinerator of the present invention is composed of a combination of an indirect heating dryer, an incinerator into which dried sludge is sent from the dryer, and a heat exchanger through which the combustion exhaust gas of the incinerator flows. One end of the heat exchange tube of the heat exchanger is connected to the drying chamber of the dryer, and the water vapor generated from the drying chamber is heated by the combustion exhaust gas (this), and the other end of the heat exchange tube is connected to the heating chamber of the dryer. and a drying chamber (which is connected to the heated steam to dry the sludge).

With this configuration, the superheated steam heated by the heat exchanger is supplied not only to the heating chamber but also to the drying chamber. It will not condense and will not be reabsorbed into the dried sludge.Therefore, in the subsequent incineration process, the combustion of the sludge will be carried out smoothly.

Furthermore, since water vapor is mixed in, the thermal coefficient does not decrease by even one inch, and the heat transfer characteristics of water vapor are not lost.

Therefore, efficient drying can be performed.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(As shown in this figure, the drying and incineration device consists of a combination of a dryer A, an incinerator B, and a heat exchanger C. In the dryer A, an inner cylinder 2 is inserted into a sealed outer cylinder 1. A drying chamber 3 is formed between the inner and outer cylinders 2 and 1 (a heating chamber 4 is formed therein, and the heat of the heating chamber 4 is transmitted into the drying chamber 3 through the wall of the inner cylinder 2, and the drying is carried out by the heat. The entrance of the inner cylinder 1 (this is where the sludge feeder 5 such as a screw conveyor is connected to the rotary damper 6
- From this feeder 5, the sludge after the ad-hoc dehydration treatment is sent to the conveyor 7 in the drying chamber 4, and is dried while being conveyed inside the drying chamber 4 by the conveyor 7. .

An exhaust port 8 is formed in the drying chamber 3. This exhaust port 8 is connected to one end of a heat exchange tube 10 of the heat exchanger C via a blower 9, and the other end of the heat exchange tube 10 is connected to an air supply port 11 of the heating chamber 4, and the drying chamber The air supply port 121 on the discharge side of No. 3 is connected via the control valve 13. By the way, both air supply ports 11. 12) In this case, a nozzle should be provided to ensure smooth mixing (rubbing is recommended).

A temperature measuring device 14 is attached to the piping from the drying chamber 3 to the heat exchanger C to detect the water vapor temperature in this piping and measure the water vapor temperature in the drying chamber 3. The degree of opening and closing of the valve 13 is adjusted to adjust the amount of water vapor that has passed through the heat exchanger C and is supplied to the drying chamber 3. In addition, the heating chamber 4 (in this case, a water vapor discharge port 15 is formed, and this discharge port 1
5 is communicated with outside air via the control valve 16, and the control valve 16
This keeps the pressure inside the heating chamber 4 constant.

A drain port 17 is formed in the lower part of the heating chamber 4, and the drain collected in the lower part of the heating chamber 4 is appropriately discharged from the drain port 17 via a drain trap 18.

A dry sludge feeder 19 such as a screw conveyor is provided at the inlet of the incinerator B, and this feeder 19 is connected to the outlet of the drying chamber 3 via a rotary damper 20. Moisture content 30
% dried sludge is sent to incinerator B. The incinerator B is provided with a burner 21, the sludge is incinerated by the burner 21, the residual ash is appropriately turned scarlet from the discharge port 22, and the combustion exhaust gas is passed through the exhaust pipe 23 in which the heat exchanger C is interposed. It passes through and is discharged.

The embodiment is configured as described above, and its operation will be explained next.

First, the sludge containing moisture is fed into the sludge feeder 5f as shown by arrow a, and is sent to the drying chamber 3 by the feeder 5, and is conveyed from the inlet (right end) to the outlet (left end) of the drying chamber 3 by the conveyor 7. It is dried by the heat from the heating chamber 4 while being moved towards it, and is discharged from the outlet as shown by the arrow. This discharged dry sludge is fed by the rotary damper 20 to the sludge feeder 19 in a timely manner as shown by the arrow CQ, and by this feeder 19 is fed into the incinerator B as shown by the arrow d to be incinerated, and the remaining ash is left behind by the arrow e. It is discharged from the discharge port 22 as shown in FIG.

On the other hand, the combustion exhaust gas generated in incinerator B is
After being led to the heat exchanger C through the exhaust pipe 23 as in b and c, it is discharged to the outside air.

The water vapor generated from the sludge in the drying chamber 3 is transferred to the blower 9 (
From there, it is fed into the heat exchanger C, where it is heated, becomes superheated, and then sent into the heating chamber 4 and the drying chamber 3. The steam sent into the heating chamber 4 radiates heat through the inner cylinder 2, and most of it becomes drain, draining into the drain port 17 and drain trap 1.
It is excreted throughout the day.

On the other hand, the sludge in the drying chamber 3 is heated and dried by the heat radiation.

In addition, the control valve 13 is opened and closed as appropriate from the measuring instrument 14, and superheated water vapor is sent into the drying chamber 3, and the water vapor in the drying chamber 3 is brought into an unsaturated state so that it will not condense even with a slight temperature drop. This is adjusted.

Therefore, since the dried sludge does not contain water again, sufficiently dried sludge is sent to the incinerator B. Also,
Since it is water vapor that is sent into the drying chamber 3, even if the water vapor in the drying chamber 3 is used as a heating source, the heat transfer coefficient does not decrease as in the case of blowing carrier air, which is efficient. Drying takes place.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a schematic piping diagram of an embodiment of the drying and incinerator of the present invention. A... Dryer, B... Incinerator, C... Heat exchanger,
3...Drying room, 4...Heating room. Patent applicant Kubota Iron Works Co., Ltd. Agent Kama 1) Text 2622

Claims (1)

[Claims] It consists of a combination of an indirect heating dryer, an incinerator into which dried sludge is sent from the dryer, and a heat exchanger through which combustion exhaust gas from the incinerator flows, and in the drying chamber of the dryer,
One end of the heat exchange tube of the heat exchanger is connected to heat the steam generated from the drying chamber with combustion exhaust gas in the heat exchanger, and the other end of the heat exchange tube is connected to the heating chamber and drying chamber of the dryer. A sludge drying and incineration apparatus characterized in that the sludge is connected to dry the sludge using the heated water vapor.