JPH0550100A - Method for incinerating sludge mixed with high molecular flocculant - Google Patents

Abstract

PURPOSE:To reduce the generation of the unburned combustibles due to incom plete combustion by adjusting the water content of sludge so that the measured value of the electrolytic current is controlled within specified limits and then supplying the sludge to an incinerator. CONSTITUTION:The sludge in a quantitative feed tank 5 is discharged on a belt conveyor 3 in fixed amts., conveyed by a feed screw 2, supplied into a multi-stage incinerator 1 from its top by the screw 2 and incinerated. Meanwhile, a rotating electrode 6 is inserted into the sludge on the conveyor 3 to continuously measure the constant-voltage electrolytic current, and the measured value is inputted to a computing element 7 through a moisture meter 4. The amt. of water to be supplied is calculated to fix the water content of sludge, the opening degree of a water feed control valve 8 is adjusted by the signal, and water is sprinkled into the tank 5 from the tip of a water feed pipe 9. Consequently, sludge having a fixed water content is supplied to the incinerator, and the sludge is stably burned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for incinerating a polymer flocculant-added sludge, and more particularly to a polymer flocculant-added sludge capable of stably burning sludge containing a polymer flocculant in an incinerator. Regarding incineration method.

[0002]

2. Description of the Related Art As one of the methods for treating sludge discharged from wastewater treatment facilities, sewage treatment facilities, etc., there is known a method of incinerating sludge in an incinerator such as a multistage furnace or a fluidized furnace. Usually, a suitable flocculant is added to the sludge before incineration, and the sludge is dehydrated with a dehydrator to obtain dehydrated sludge with a water content of about 80% by weight.
Supplied to the incinerator. In recent years, polymer flocculants have been used as flocculants instead of inorganic flocculants such as lime,
The dehydrated sludge (polymer sludge) thus obtained has a high solid content calorific value and a low water content of about 75% by weight. Therefore, in a multi-stage furnace, combustion of the polymer sludge becomes unstable due to changes in water content. If the water content falls below a certain value, a large amount of unburned components will be generated due to incomplete combustion.
Moreover, since sludge becomes a self-combustion state in the upper stage of the multistage furnace, it was necessary to install a heat removal device and a cold gas circulation device. Also in the fluidized reactor, since sludge with a low water content and high calorific value is likely to be in a self-combustion state, it was necessary to install a combustion air cooling device, a cooling water sprinkling device, and the like.

Conventionally, the water content of sludge supplied to an incinerator is
The water content was adjusted by using an automatic moisture meter that uses far-ultraviolet rays, and this adjustment was made by drying the sampled sludge and measuring it by the weight drying method. Since sampling was required, continuous measurement was not possible and it was not possible to follow up when the properties of sludge suddenly changed.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to supply a polymer coagulant-added sludge to an incinerator for stable combustion and incineration. It is to provide a method for incinerating added sludge.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the inventors of the present invention have proposed a rotating electrode previously applied (Japanese Patent Application No. 2-9).
8376) was applied to the measurement of the water content of sludge to follow the properties of the sludge, and by continuously adjusting the water content of the sludge, it was found that stable sludge incineration in an incinerator can be achieved. The present invention has been reached.

According to the present invention, when supplying sludge containing a polymer coagulant to an incinerator for incineration, at least a pair of cathode and anode are provided with rotating electrodes provided in parallel with rotating terminals at intervals of 1 mm or less. It is installed in sludge, a constant voltage is applied to the rotary electrode to measure an electrolysis current, and after adjusting the water content of the sludge so that the measured value falls within a predetermined range, the sludge is supplied to an incinerator. The present invention relates to a method for incinerating sludge containing a polymer flocculant.

The rotating electrode used in the present invention has at least one pair of cathode and anode of 1 mm or less, preferably 0.
The rotating terminals are provided in parallel at intervals of about 75 to 0.1 mm, more preferably about 0.5 to 0.3 mm. By installing the cathode and anode parallel to the rotary terminal at intervals of 1 mm or less, the fixed electrode is not installed in the sample, and the amount of water in the sample is not restricted by the sample in which the diffusion layer is easily obtained. Since a proportional and stable electrolytic current can be generated, the amount of water can be calculated from this current value. Further, by using such a rotating electrode, it is possible to prevent the adhesion of sludge to the electrode surface,
It enables continuous current measurement. When calculating the water concentration from the electrolysis current value, it is preferable to perform temperature correction in order to improve the measurement accuracy.

The present invention will be described below with reference to the drawings.

[0009]

EXAMPLE FIG. 1 is an explanatory view of a sludge supply device for a multistage incinerator showing an example of the present invention. In FIG. 1, a sludge supply device for a multi-stage incinerator comprises a constant amount supply tank 5 for supplying a fixed amount of sludge, and a belt conveyor 3 for conveying the sludge discharged from the constant amount supply tank 5 and introducing it into the multi-stage incinerator 1. And a feeding screw 2, a moisture meter 4 connected to the rotary electrode 6 installed in the sludge on the belt conveyor 3, and a signal measured by the moisture meter 4 to calculate the amount of water for keeping the moisture content of the sludge constant. And a water supply control valve 8 that adjusts the amount of water to be sprayed based on a signal from the calculator 7.

In such a construction, the sludge in the fixed amount supply tank 5 is discharged to the belt conveyor 3 after being adjusted to a certain amount, conveyed to the feeding screw 2, and then fed by the feeding screw 2 from the top of the multistage incinerator 1. It is supplied to the furnace and incinerated. On the other hand, the constant voltage electrolysis current of the sludge is continuously measured by the rotary electrode 6 inserted in the sludge on the belt conveyor 3 and is input to the calculator 7 through the moisture meter 4, where the water content of the sludge is constant. The water supply amount is calculated so that the opening degree of the water supply control valve 8 is adjusted by the signal, and water is sprayed from the tip of the water supply pipe 9 into the fixed amount supply tank 5.

The sludge supplied to the multistage furnace is usually 78 to 8
Adjusted to 0% by weight. The mounting position of the rotating electrode 6 is
It is not limited to the belt conveyor 3, and may be installed, for example, in the sludge in the constant amount supply tank 5 or the charging screw 2. The position where the water is sprayed is not limited to the fixed amount supply tank 5, and may be, for example, the belt conveyor 3 or the charging screw 2. FIG. 2 shows a perspective view of the rotary electrode 6 used in FIG. In FIG. 2, the rotating electrode 6 has a pair of cathodes 12 and anodes 13 provided in parallel at intervals of 1 mm or less, and the cathodes 12 and 13 are fixed, and only the tips of these are exposed.
Insulating part 16 which insulates from other components, and the cathode 12
And an anode 13, and a current collecting brush 14 and a power feeding ring 15 for connecting the anode 13 to the power source and the meter side, respectively.

A noble metal such as platinum is used as the material forming the cathode and the anode, and copper, SUS or the like can be used as the cathode. The exposed positions of the cathode 12 and the anode 13 are provided at the bottom of the rotary electrode 6, but they may be provided at the side or the comb-shaped electrode. Insulation part 16
As the resin, a resin such as an epoxy resin, a vinyl chloride resin, a phenol resin, or ceramics is used. From the viewpoint of measurement accuracy, the length of the electrode is preferably short, 20 to 10 mm.
The thickness is preferably the following, and more preferably about 5 mm.

In this way, the electrolytic current value in the sample is continuously measured using the above-mentioned specific rotating electrode, and water is supplied so that the current value falls within a certain range, whereby the water content becomes constant. Since it is possible to supply the sludge to the multi-stage incinerator, it is possible to stably burn the sludge. The same effect can be obtained even if the same method is adopted in the flow furnace.

[0014]

According to the present invention, the electrolytic current value of water in sludge can be measured rapidly and continuously by using the rotary electrode in which the cathode and the anode are parallel to each other at intervals of 1 mm or less on the rotary terminal. However, since the water content of the sludge can be adjusted to a constant value based on the current value, it is possible to prevent the self-combustion state of the sludge in the incinerator and perform stable sludge combustion, as well as unburned due to incomplete combustion. The generation of minutes can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a sludge supply device for a multistage incinerator showing an embodiment of the present invention.

FIG. 2 is a perspective view of the rotary electrode used in FIG.
1 ... Multi-stage incinerator, 2 ... Input screw, 3 ... Belt conveyor, 4 ... Moisture meter, 5 ... Fixed amount supply tank, 6 ... Rotating electrode, 7
... arithmetic unit, 8 ... water supply control valve, 9 ... water supply pipe, 12 ... cathode, 13 ... anode, 14 ... collector brush, 15 ... power supply ring, 16 ... insulation part.

Claims (1)

[Claims] 1. When supplying sludge containing a polymer flocculant to an incinerator for incineration, at least one pair of cathode and anode are provided with rotating electrodes parallel to each other at intervals of 1 mm or less on a rotating terminal, and Is installed in the rotary electrode, a constant voltage is applied to the rotating electrode to measure an electrolytic current, and the water content of the sludge is adjusted so that the measured value falls within a certain range, and then the sludge is supplied to an incinerator. Incineration method of sludge containing molecular coagulant.