JPS6152365B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for evaporating and oxidizing wastewater from an incinerator by directly blowing it into an incinerator, and more specifically, it is a method that ensures reliable injection of wastewater from an incinerator into an incinerator over a long period of time. This article concerns methods for evaporating and oxidizing wastewater from incinerators.

Municipal waste incineration plants generate various types of wastewater, including incinerator wastewater (for example, wastewater from garbage pits, wastewater from smoke washing, etc.). Therefore, these wastewaters (hereinafter referred to as "incinerator wastewater") are generally either (1) discharged after removing harmful components in wastewater treatment equipment, or
(2) It is treated by blowing it directly into the incinerator and evaporating and oxidizing it. In particular, the latter method does not require complicated and expensive wastewater treatment equipment unlike the former method, that is, the discharge system, and also has the function of adjusting the internal temperature of the incinerator, so it is recommended as a method for treating wastewater from an incinerator. It is considered extremely useful.

FIG. 1 is a schematic diagram illustrating a method for evaporating and oxidizing wastewater from an incinerator. In the following explanation, incineration plant wastewater will be simply referred to as "drainage". In FIG. 1, 1 represents a waste water tank, 2 represents a waste water blowing section, and 3 represents an incinerator. In addition, the drainage blowing section 2 is constructed as shown in FIG.
A nozzle 8 facing the inside of the furnace is provided in the air inlet 6 drilled in the
is installed, and the nozzle 8 is a so-called one-fluid water spray nozzle. Now, the wastewater _L1 drawn up by a pump or the like from a drainage pit, which is not shown in the figure, is once introduced into the wastewater tank 1 after undergoing foreign matter removal treatment using various screens and strainers. Next, this waste water L ₁ is blown into the incinerator 3 from the nozzle 8 of the waste water blowing section 2 via the solenoid valve 5 by the pump 4 . The waste water L ₁ blown in in this manner is evaporated and oxidized in the furnace, but at this time the temperature inside the furnace also decreases, which also produces the effect of preventing overheating of the furnace body or grate. However, if too much waste water is blown in, the temperature inside the furnace will drop too much and the combustion condition inside the furnace will worsen, so to prevent this from happening, the amount of waste water blown in should be adjusted to the temperature inside the furnace. It is necessary to control accordingly. Therefore, conventionally, as shown in Fig. 1, a temperature measuring element 7 is installed near the exhaust gas outlet of the incinerator 3, and when the measured temperature is above a certain reference temperature (usually 750°C is the standard), This is a so-called on-off system that blows wastewater into the area and stops the injection if the temperature is below the reference temperature.
An off switching operation is being performed. Such on/off control of the drainage water blowing is performed by opening and closing the solenoid valve 5 in response to a signal from the temperature measuring element.

By the way, if the nozzle 8 is left in the furnace while the injection of wastewater is stopped, the nozzle will be exposed to the high temperature atmosphere inside the furnace and its temperature will rise, causing deformation and a decrease in strength. (ash, etc.) that clogs the nozzle tip. Therefore, when the blowing of waste water is stopped, the nozzle 8 is moved back from the furnace wall 1a by a reciprocating mechanism such as a cylinder or a rack pinion, and is configured to advance into the furnace only during the blowing. However, since the advancing and retracting mechanism is installed around the furnace wall, that is, in a high-temperature, dusty area, failures often occur, and when this occurs, there is a problem in that the wastewater cannot be blown into the furnace itself.

On the other hand, for continuous operation of wastewater blowing, nozzle 8
In addition to the blockage of the drain pipe 20, the drain pipe line 20 may also be blocked. This is due to the solid particles contained in the waste water flowing through the drain pipe 20, and by allowing the waste water to flow through the drain pipe 20 for a long time, it accumulates in the pipe 20 as so-called scale, which causes the pipe to become clogged. This was because the road gradually became narrower and eventually became blocked. Furthermore, when the drainage water supply is stopped, the wastewater accumulated in the narrow pipe is evaporated by the radiant heat from the furnace, and the residue is stuck to the wall of the pipe, which is also one of the factors that promotes the above-mentioned clogging phenomenon.

Furthermore, the amount of wastewater in an incinerator fluctuates depending on the type of waste being thrown into the incinerator, but if the amount of water is too small to store enough wastewater to be treated in the wastewater tank, the injection of wastewater will naturally be stopped. Ru. As a result, the blowing nozzle may be exposed to high temperatures and suffer heat loss, or the blowing line may become clogged due to stagnation of the flow, and there are also problems in that the cooling effect within the furnace is lost. Therefore, it is necessary to carry out evaporation and oxidation treatment of wastewater in response to such daily fluctuations in the amount of wastewater.

The present invention was made with attention to these circumstances, and the present inventor has developed a two-fluid nozzle, which the inventor has separately developed and applied for utility model registration, for incineration plant wastewater that can be used by fixing it to the furnace wall. The present invention aims to provide a method for evaporation and oxidation treatment of

That is, FIG. 3 is a schematic explanatory diagram illustrating a two-fluid nozzle that can be applied to the present invention, and FIG. 4 is a cross-sectional view taken along the line -- in FIG.
An air introduction pipe 14 is installed in 2, and a liquid introduction pipe 15 is installed inside the outer cylinder 10 by extending it in substantially the same direction as the outer cylinder 10. A steel cylinder opening 13 is attached to the inner end of the outer cylinder 10. are doing. Therefore, the outer cylinder 10 itself is formed as an air introduction passage. The two-fluid nozzle is fixed at an appropriate entry position by a tightening bolt 18.

Now, in order to evaporate and oxidize the liquid, air is supplied from the air introduction pipe 14 and liquid is simultaneously supplied from the liquid introduction pipe 15, and the two are mixed and then transferred to the tube opening 13.
Spray from the tip. On the other hand, when the liquid is not evaporated or oxidized, only the liquid supply is stopped and the air supply is continued, so in any case, air flows through the liquid nozzle, and its cooling effect prevents burnout of the two-fluid nozzle. be done. This eliminates the need to extract the nozzle out of the furnace using a cylinder mechanism or the like as in the case of the nozzle shown in FIG.

The present invention uses such a two-fluid nozzle and allows wastewater to be blown into an incinerator to adjust the temperature inside the incinerator and evaporate and oxidize the wastewater for a long time without causing problems such as clogging of the wastewater injection equipment. The purpose of the present invention is to provide a method for evaporating and oxidizing wastewater that can smoothly blow wastewater across the incinerator and that can respond to daily fluctuations in the amount of waste thrown into the incinerator. .

However, the wastewater evaporation/oxidation treatment method of the present invention is a treatment method in which wastewater is blown into an incinerator to adjust the temperature inside the furnace and evaporate/oxidize the wastewater, and a two-fluid nozzle is installed on the furnace wall. In addition to opening and installing the nozzle, an air introduction pipe and a liquid introduction pipe are connected to the inlet side of the nozzle, and the liquid introduction pipe is connected to a drain tank and a new water tank via a 3-way connector. Injection is carried out throughout the entire operation period, and water suction is controlled on and off according to the temperature inside the furnace, and switching between waste water spray and fresh water spray is performed when the total amount of waste water or fresh water injected or the cumulative time reaches a certain standard. This is done in accordance with the ivy stage or a decrease in the amount of wastewater or fresh water stored.

The present invention will be explained below based on the drawings of the embodiments.
The embodiments are not intended to limit the present invention, and any design changes made as appropriate in accordance with the spirit described above and below are all included within the technical scope of the present invention.

FIG. 5 is a flow explanatory diagram of the method for evaporating and oxidizing waste water according to the present invention, in which 1 indicates a garbage pit drainage tank, 19 indicates a fresh water tank, and 3 indicates an incinerator. A temperature measuring element 7 is installed near the exhaust gas outlet of the incinerator 3, and the two-fluid nozzle 8a is installed in the waste water blowing section 2 provided in the incinerator 3. Further, a liquid pipe line 20 and a gas pipe line 21 are connected to the blowing section 2. And the liquid pipe line 20 has a solenoid valve 5.
a, a pump 4a and a three-way valve 22 are interposed, and the three-way valve 22 is divided into a drainage pipe 23 and a new water pipe 24. Further, a solenoid valve 5b and a compressor 25 are interposed in the gas pipe 21. Furthermore, a water level gauge 26 and a water level gauge 26a are installed in the drain tank 1 and the new water tank 19. Reference numeral 7 denotes a temperature measuring element, and the temperature measurement result is inputted to a command unit 27, and the temperature measuring element 7 is configured to command the operation of the electromagnetic valve 5a and the pump 4a in accordance with the input.

When performing evaporation and oxidation treatment of waste water using the above flow, first the compressor 25 is operated to send air from the gas pipe 21 to the two-fluid nozzle 8a. On the other hand, the flow path of the three-way valve 22 in the liquid pipe line 20 is set to the drain tank 1 side, and the pump 4a is started.
The waste water is fed to the two-fluid nozzle 8a via the solenoid valve 5a. In this way, the waste water and air are combined at the mouth of the two-fluid nozzle 8a and are blown and dispersed into the furnace in the form of mist. Next, when the drainage water blowing is continued for a predetermined period of time, the liquid pipe 2
Since scale and the like accumulate in the 0 and 2 fluid nozzles 8a, the pump 4a is temporarily stopped, the solenoid valve 5a is closed, and the 3-way valve 22 is switched to the fresh water side. Thereafter, the electromagnetic valve 5a is opened and the pump 4a is started to supply fresh water to the liquid pipe line 20 and the two-fluid nozzle 8a to clean the inside of the pipe line. If the cleaning is continued for a predetermined period of time, the inside of the pipe will be sufficiently cleaned, so after stopping the pump 4a and closing the solenoid valve 5a, the flow path of the three-way valve 22 is returned to the drain tank 1 side, and then the inside of the pipe is cleaned again. The solenoid valve 5a is opened and the pump 4a is started to restart the wastewater blowing process. After that, repeat the above operation. The above operations are performed by electrical commands from a specific control circuit, and this control method will be explained below.

FIG. 6 is a time chart of the control circuit.
The time chart shows elapsed time on the horizontal axis, and after setting the control circuit to automatic operation mode at time S, at time _t1 , the flow path of the three-way valve 22 is switched to the drain tank 1 side, and the pump 4a is started. Then, the wastewater injection process is started, and at the same time, a wastewater amount integration timer (hereinafter referred to as "drainage timer") _M1 is activated. Next, at time t ₂ (assuming that the accumulated time of the drain timer M ₁ has not reached the set time (T ₁ ) yet), the blowing stop factors (lower temperature inside the furnace, decrease in water level in the drain tank 1, etc.), which will be described later, are detected. ) is detected, the pump 4a stops, and at the same time, the integration of the drain timer _M1 is also interrupted. When it is detected that the cause of stopping the blowing is eliminated, the pump 4a is restarted, and the drain timer _M1 restarts integration. By repeating such control, drainage is continuously sucked, and when the accumulated time of the drainage timer _M1 reaches the set time _T1 (that is, when it reaches time _t4 ), the pump 4a and the drainage timer _M1 are stopped. do. Then, instantaneously or as shown in the figure (when a predetermined period of time has elapsed and the time point _t5 is reached, the flow path of the three-way valve 22 is switched to the fresh water tank 19 side and the pump 4a is started. At this time, the drain timer _M1 is New water amount accumulation timer (hereinafter simply referred to as "new water timer")
_M2 starts. Hereinafter, as in the case of the wastewater blowing operation, when a blowing stop factor occurs, the fresh water blowing operation is performed while the blowing is interrupted (that is, the pipe line 20 and nozzle 8a are cleaned), and the cumulative time of the fresh water timer _{M2 is} When the set time T ₂ necessary for cleaning is reached, the pump 4a and the fresh water timer M ₂ are stopped. Then, when a predetermined period of time has passed and the time point _t9 is reached, the drainage water injection is restarted again. Thereafter, while repeating the same control cycle, the injection of waste water and the injection of fresh water are performed alternately.

In addition to the operation switching circuit using the integration timer as described above, the control circuit incorporates a temperature control circuit using the temperature measuring element 7, a water level control circuit using the water level gauges 26, 26a, and the like.

In other words, the temperature control circuit is similar to the conventional one, and when the temperature inside the furnace falls below the set temperature, the injection of drainage water or fresh water is stopped and the inside of the furnace is not cooled more than necessary. When the detected furnace temperature is below the set temperature, the pump 4a and the solenoid valve 5 are activated.
When a stop signal is sent to the pump 4a and the solenoid valve 5a, if the temperature inside the furnace returns to the reference temperature or higher.
A start signal is sent to

In addition, water level gauges 26 and 26a are installed in the drainage tank 1 and the new water tank 19, respectively, and when the water level falls below the lower limit water level, the operation is stopped, and when the water level rises above a predetermined water level, an operation restart signal is sent. .

The present invention is structured as described above, but the main points are two.
Incorporating the advantages of a fluid nozzle (however, its structure is not limited), this system blows wastewater into the furnace and performs evaporation and oxidation while responding to various fluctuating conditions associated with incinerator operation. Various effects can be obtained as summarized below.

(1) Wastewater can be reliably and stably blown into the furnace over a long period of time without causing blockages in the blowing nozzle or the wastewater supply pipe.

(2) The wastewater can be reliably blown into the furnace in response to fluctuations in the amount of wastewater generated from the incinerator.

(3) By using a two-fluid nozzle, there will be no structural failure at the wastewater injection section, which will greatly contribute to long-term security of wastewater injection into the furnace.

[Brief explanation of the drawing]

Fig. 1 is a schematic system explanatory diagram showing a conventional method for evaporating and oxidizing wastewater, Fig. 2 is an enlarged explanatory diagram of the broken line circle in Fig. 1, and Fig. 3 is a schematic cross-section of a two-fluid nozzle according to the present invention. Figure 4 is a sectional view taken along the line - - in Figure 3, Figure 5 is a schematic system explanatory diagram illustrating the wastewater evaporation and oxidation treatment method of the present invention, and Figure 6 is an automatic method of the embodiment shown in Figure 5. FIG. 2 is an explanatory diagram of a time schedule of a control circuit during controlled operation. 1...Drainage tank, 2...Drainage blowing part, 3...
Incinerator, 4a...Pump, 5a, 5b...Solenoid valve, 7...Temperature sensor, 8...1 fluid nozzle, 8a...
...Two-fluid nozzle, 10... Outer cylinder, 13... Cylinder mouth,
14...Air introduction pipe, 15...Liquid introduction pipe, 19
...New water tank, 22...3-way valve, 26, 26a
...Water level gauge, 27...Command department.

Claims (1)

[Claims] 1 A treatment method in which wastewater from an incinerator is blown into an incinerator to adjust the temperature inside the furnace and evaporate and oxidize the wastewater, in which a two-fluid nozzle is opened and installed on the furnace wall, and a two-fluid nozzle is installed on the inlet side of the nozzle. Connect the air inlet pipe and the liquid inlet pipe, and connect the liquid inlet pipe to the incinerator wastewater tank and new water tank via a three-way joint. Air is blown throughout the entire operation period, and the incinerator The water injection is controlled on and off according to the internal temperature, and the switching between waste water spray and fresh water spray is performed when the total amount of waste water or fresh water injected or the cumulative time reaches a certain standard, or when the amount of waste water or fresh water is stored. A method for evaporating and oxidizing wastewater from an incinerator, characterized in that the treatment is carried out in response to a decrease in wastewater from an incinerator.