JPH0442046A - Pressure-sending method for sludge - Google Patents

Abstract

PURPOSE:To make it possible to stabilize the operation of a sludge pressure- sending pump by measuring an electrolytic current value, and feeding water so that the current value is in a specified range. CONSTITUTION:At least a pair of a cathode and an anode are provided at rotary terminals of a rotary electrode 6 in parallel at an interval of 1 mm or less. The rotary electrode 6 is provided at the side of the inlet port of a sludge pressure-sending pump 3. A specified voltage is applied on the electrode 6, and an electrolytic current is measured. The value is inputted into an operator 7. The operator 7 receives the value and computes the water feeding amount so that the moisture content of dehydrated sludge 10 becomes constant. Then, a water-supply adjusting value 8 adjusts the opening degree based on the signal. Water is supplied into the sludge 10 through the tip part of a water feeding pipe 11. Then, the sludge 10 is sent into the pump 3 by the rotation of a screw 2. The, the pump 3 inputs the sludge 10 into an incinerator through a pressure- sending line 5. In this way, the eletrolytic current is continuously measured by using the electrode 6, and the water is supplied so that the current value is in the specified range. Thus, the moisture content of the sludge 10 is kept in the specified range, and the sludge can be supplied into the pump 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for pumping sludge, and more specifically, it is possible to stably supply sludge to an incinerator, etc. while keeping the moisture content of sludge constant with simple operations. This article relates to a method for pumping sludge.

[Prior Art] Conventionally, a method of burning dehydrated sludge in an incinerator has been known as one of the methods of treating dehydrated sludge. The dehydrated sludge that is burned in the incinerator is pumped and supplied by a sludge pressure pump, but if the moisture content of the dehydrated sludge is low, there is a problem that the pressure loss in the pipes increases and the pump becomes overloaded. Ta. To avoid this, conventional measures include installing a pump protection circuit that detects the pressure inside the sludge pipe at the pump outlet or measures the current value of the pump motor. but,
-When the pump becomes overloaded and stops, it is necessary to disassemble the pump and restore it, which is a huge effort. Furthermore, when sludge is pumped and burned in an incinerator, there is a problem that stable combustion in the incinerator cannot be achieved if there is a difference in the water content of the sludge.

Conventionally, automatic moisture meters that use far ultraviolet light have been used to measure the moisture content of dehydrated sludge;
The sampled sludge is dried and measured using the gravimetric drying method, which requires a long response time and requires sampling, making continuous measurement impossible and unable to follow sudden changes in sludge properties.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the problems of the prior art described above, and to provide a method that can quickly measure the water content in sludge, maintain it within a certain range, and supply it to a sludge pressure pump in a stable state. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the present inventor has stabilized the sludge without overloading the pump by applying the previously filed rotating electrode (Japanese Patent Application No. 2-98376) to sludge pumping. It was discovered that the present invention can be carried out under pressure.

In the present invention, when sludge stored in a hopper is pumped by a sludge pump, at least one pair of a cathode and an anode are provided in the sludge on the inlet side of the sludge pump in parallel at a rotating terminal with an interval of 1 m or less. Install the rotated electrode,
Sludge pumping characterized by applying a constant voltage to the rotating electrode to measure an electrolytic current, and supplying water into the sludge on the upstream side of the sludge pump so that the measured value falls within a certain range. Regarding the method.

In the rotating electrode used in the present invention, at least one pair of a cathode and an anode has a length of less than lam, preferably from 0.75 m to 0.3 m.
1 m, more preferably 0.5111111-0.3 m
They are provided on the rotating terminals in parallel at a certain interval.

By arranging the cathode and anode parallel to each other at a spacing of 1-1 or less on the rotating terminal, there is no need to install a fixed electrode in the sample, and the sample is not limited to a sample where a diffusion tank can be easily obtained. Since it is possible to generate a stable electrolytic current proportional to the amount of electrolysis, it is possible to calculate the amount of water from this current value.Also, by using such a rotating electrode, it is possible to prevent sludge from adhering to the electrode surface. Therefore, continuous current measurement is possible.In addition, when calculating the water concentration from the electrolytic current value, it is preferable to perform temperature correction in order to improve measurement accuracy.

Hereinafter, the present invention will be explained with reference to the drawings.

〔Example〕

FIG. 1 is a block diagram of a dewatered sludge supply device showing one embodiment of the present invention, and FIG. 2 is a perspective view of a rotating electrode used in FIG. 1.

In FIG. 2, the rotating electrode 6 consists of a pair of cathodes 12 and anodes 13 that are provided in parallel with an interval of ① floor plan, and the cathodes 12 and anodes 3 are fixed, and only their tips are fixed. an insulating portion 16 that is exposed and insulated from other components;
It consists of a current collecting brush 14 and a power feeding ring 15 that connect the cathode 12 and anode 13 to a power source and a measuring section, respectively.

A noble metal such as platinum is used as the material constituting the cathode and the anode, and copper, SUS, etc. can also be used for the cathode. The exposed position of the cathode 12 and anode 13 is the rotating electrode 6
Although the electrodes are provided at the bottom, they may also be provided at the sides, or may be comb-shaped electrodes. For the insulating portion 16, resins such as epoxy resin, vinyl chloride resin, and phenol resin, ceramic, and 7x are used. The length of the electrode is preferably shorter from the viewpoint of measurement accuracy, preferably 20 to 10 mm or less, and more preferably about 5 mm.

In FIG. 1, the dehydrated sludge supply device includes a conveyor 9 that conveys dehydrated sludge 10 dehydrated by a dehydrator (not shown) or the like to a hopper 1, and a conveyor 9 provided at the bottom of the hopper 1.
A screw 3 for sending out sludge, and the screw 3
a sludge pump 3 for pumping the sludge 10 sent out, a pumping line 5 for transporting the pumped sludge to an incinerator (not shown), and a dehydrated sludge on the inlet side of the sludge pump 3. a rotating electrode 6 provided in the rotary electrode 6; a computing unit 7 that calculates the amount of water required to maintain the water content of dehydrated sludge constant from the current value measured by the rotating electrode 6; and the computing unit 7.
Water supply control valve 8 that adjusts the amount of water supplied by a signal from
and a water supply pipe 11 that supplies water to the upstream side of the screw 2.

In such a configuration, the dewatered sludge 10 transported by the transport conveyor 9 is stored in the hopper 1 and fed into the sludge pump 3 by rotation of the screw 2. On this occasion,
Rotary FiiA installed on the inlet side of the sludge pump 3
6 measures the constant voltage electrolytic current and inputs it to the calculator 7. The arithmetic unit 7 calculates the water supply amount from the input current value so that the water content of the dehydrated sludge is constant, and the opening degree of the water supply control valve 8 is adjusted based on the signal, and the water supply pipe 11 is
Screw 2 from the tip (nozzle or perforated pipe, etc.)
Water is supplied into the dewatered sludge on the upstream side of the sludge.

On the other hand, the dehydrated sludge pumped by the sludge pump 3 is fed into the incinerator via the pumping line 5 and burned.

The moisture content of dehydrated sludge suitable for pumping with the sludge pump 3 is usually as follows for sewage sludge to which a polymer additive has been added.
It is in the range of 78% to 90%.

In this way, by continuously measuring the electrolytic current value in the sample using the above-mentioned specific rotating electrode and supplying water so that the current value is within a certain range, dehydration with a constant water content can be achieved. It becomes possible to supply sludge to the sludge pump.

〔Effect of the invention〕

According to the present invention, by using a rotating electrode in which a cathode and an anode are provided in a rotating terminal in parallel with an interval of 1IIIfi or less, the electrolytic current value of water in sludge can be rapidly measured almost in real time, Water can be supplied to the dehydrated sludge by calculating the amount of water supplied so that the current value is within a certain range, and the sludge can be supplied to the pressure pump while maintaining the water content in the sludge within a certain range. This enables stable operation of the sludge pump, and also enables stable combustion of the pumped sludge in the incinerator.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a dewatered sludge supply device showing one embodiment of the present invention, and FIG. 2 is a perspective view of a rotating electrode used in FIG. 1. ■... Hopper, 2... Screw, 3... Sludge pressure pump, 4... Motor, 5... Force feeding line, 6...
...Rotating electrode, 7...Arithmetic unit, 8...Water supply control valve, 9...Transport conveyor, lO...Dehydrated sludge, 11.
...Water supply pipe, 12...Cathode, 13...Anode, 14
...Power supply brush, 15...Current collection link, 16...
Insulation section.

Claims (1)

[Claims] (1) When the sludge stored in the hopper is pumped by the sludge pump, at least one pair of cathode and anode are provided in the rotating terminal in parallel with an interval of 1 mm or less in the sludge on the inlet side of the sludge pump. A rotating electrode is installed, a constant voltage is applied to the rotating electrode, an electrolytic current is measured, and water is supplied into the sludge on the upstream side of the sludge pump so that the measured value is within a certain range. A sludge pumping method characterized by: