JP2011237046A - Waste liquid treating apparatus and waste liquid treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste liquid treating apparatus and a waste liquid treating method that efficiently treat waste liquids when incinerating a plurality of waste liquids by a dry distillation gasification incinerator.SOLUTION: When a waste liquid is supplied to a second combustion furnace 4 which incinerates the waste liquid, a temperature T1 set in a first combustion furnace 3 is controlled to a first set temperature T1max so that a temperature T2 in the second combustion furnace 4 is equal to or higher than a temperature for thermally decomposing dioxins etc., and when no waste liquid is supplied to the second combustion furnace 4, the set temperature is controlled to a second set temperature T1min, set to a low-temperature range side within a temperature range in which the temperature T1 in the first combustion furnace 3 is a temperature for thermally decomposing dioxins and self-combustion is maintained.

Description

  The present invention relates to a waste liquid processing apparatus and a waste liquid processing method for incinerating a waste liquid.

  In recent years, waste liquids such as photographic development waste liquids are incinerated by continuously spraying the waste liquid into a combustion furnace in order to perform economical and efficient treatment while satisfying the demand for pollution-free waste liquids. Has been devised (see, for example, Patent Document 1).

  By the way, the present applicant, as an apparatus for incinerating waste such as waste tires while preventing the discharge of dioxins, stores the waste and burns a part of the waste, Proposed a dry distillation gasification incineration apparatus comprising a distillation furnace in which the remainder of the waste is dry-distilled by combustion heat to generate a combustible gas, and a combustion furnace in which the combustible gas is introduced from the dry distillation furnace and completely combusted (For example, refer to Patent Document 2).

  In such a dry distillation gasification incineration processing apparatus, waste is batch-processed in a dry distillation furnace, and while combustible gas is generated from the dry distillation furnace, the waste liquid is continuously sprayed onto the combustion furnace. It is possible to treat a certain amount of waste liquid per batch.

JP-A-7-91637 Japanese Patent No. 4005770

  Here, when several types of waste liquids are treated, it is desirable from the viewpoint of treatment efficiency that the mixed liquids are mixed and then continuously sprayed onto the incinerator. However, different types of waste liquids may react by mixing. Can not be mixed. Therefore, in the dry distillation gasification incineration processing apparatus, it is difficult to synchronize the timing of the batch processing and the waste liquid incineration processing, and it has been considered unsuitable for processing a plurality of waste liquids.

  The inventor has conducted various studies on the incineration timing of the waste liquid in the dry distillation gasification incineration processing apparatus, and as a result, it is possible to treat different types of waste liquid without mixing the waste liquids by keeping a certain time interval. I found out that there was.

  Then, based on this knowledge, this invention aims at providing the waste liquid processing apparatus and waste liquid processing method which can process a waste liquid efficiently, when incinerating a some waste liquid in a dry distillation gasification incineration processing apparatus. And

  In order to achieve the above object, the present invention provides a waste liquid treatment apparatus that incinerates a plurality of waste liquids. The waste liquid treatment apparatus stores waste and burns part of the waste while burning the waste by the combustion heat. A distillation furnace for producing a combustible gas by dry distillation of the remainder of the product; a first combustion furnace for combusting a combustible gas introduced from the dry distillation furnace; and an amount of the combustible gas introduced into the first combustion furnace. Combustion oxygen supply means for supplying the oxygen required for the combustion to the first combustion furnace according to the above, first temperature detection means for detecting the temperature in the first combustion furnace, and the combustible gas in the first combustion furnace Dry distillation oxygen supply for adjusting the oxygen supply amount to the first dry distillation furnace so that the temperature in the first combustion furnace detected by the first temperature detection means is maintained at a set temperature after the start of combustion of Means, connected to the first combustion furnace, and introduced from the first combustion furnace. A second combustion furnace for incinerating the waste liquid by combustion heat; a waste liquid supply means for supplying the waste liquid to the second combustion furnace; and a second temperature detection means for detecting a temperature in the second combustion furnace. When the waste liquid is supplied to the second combustion furnace, the temperature in the second combustion furnace detected by the second temperature detecting means is equal to or higher than the temperature at which dioxins can be thermally decomposed. When the set temperature is controlled to the first set temperature and no waste liquid is supplied to the second combustion furnace, the temperature in the first combustion furnace detected by the first temperature detecting means is dioxins. The set temperature is controlled to a second set temperature set to a temperature range lower than a temperature range in which self-combustion is maintained at a temperature higher than the temperature at which the thermal decomposition is possible.

  According to the waste liquid treatment apparatus of the present invention, in the dry distillation gasification incineration treatment apparatus for combusting the combustible gas introduced from the dry distillation furnace in the first combustion furnace, the combustion heat generated in the first combustion furnace is transferred to the second combustion furnace. Introduce and treat waste liquid. At this time, the set temperature of the first combustion furnace is controlled as follows depending on whether or not the waste liquid is supplied to the second incinerator.

  That is, when the waste liquid is supplied to the second incinerator, the temperature of the second combustion furnace decreases due to the heat of vaporization of the supplied waste liquid. Therefore, the set temperature of the first combustion furnace is controlled to the first set temperature so that the temperature in the second combustion furnace is equal to or higher than the temperature at which dioxins can be thermally decomposed. Therefore, the first set temperature can be set to a temperature suitable for the incineration treatment of the waste liquid while preventing the discharge of dioxins due to the incineration treatment of the waste, and the waste liquid can be processed efficiently.

  On the other hand, when the waste liquid is not supplied to the second combustion furnace, the temperature drop in the second combustion furnace hardly occurs, so the set temperature of the first combustion furnace is lower than that when the waste liquid is supplied. Can be made. Here, the temperature in the first combustion furnace is (1) maintained at a temperature higher than the temperature at which dioxins can be thermally decomposed, and (2) a temperature at which self-combustion is maintained even when the set temperature is lowered. There is a need to. Therefore, the temperature of the first combustion furnace is controlled to the second set temperature set on the low temperature region side within the range satisfying the conditions (1) and (2).

  The combustion heat generated in the first combustion furnace while the waste liquid is not being supplied to the second combustion furnace is not used for the treatment of the waste liquid and causes a reduction in the processing amount of the waste liquid. By setting the temperature to a lower temperature within the range satisfying the conditions (1) and (2), it is possible to suppress the generation of combustion heat that is not used for waste liquid treatment. That is, by controlling the set temperature to the second set temperature, the amount of combustible gas generated in the dry distillation furnace is suppressed so that the temperature in the first combustion furnace becomes the second set temperature. Then, when the waste liquid is supplied next time, the combustible gas corresponding to the generation is suppressed, and the combustion heat can be used for the treatment of the waste liquid.

  As described above, according to the waste liquid treatment apparatus of the present invention, when a plurality of waste liquids are incinerated in the dry distillation gasification incineration processing apparatus, the waste liquid can be efficiently incinerated while suppressing a decrease in the processing amount.

  The waste liquid of the present invention can contain waste oil, sludge, etc. that can be incinerated.

  The waste liquid treatment apparatus of the present invention includes a plurality of waste liquid storage means for storing the waste liquid, and a supply means for supplying the waste liquid from each waste liquid storage means to the second combustion furnace, and the waste liquid is generated by the supply means. When being supplied, the set temperature is controlled to the first set temperature, and when the waste liquid is not supplied by the supply means, the set temperature is controlled to the second set temperature. Features.

  According to this waste liquid treatment treatment, when there are a plurality of waste liquid storage means, the set temperature of the first combustion furnace is controlled from the first temperature to the second temperature in synchronization with the presence or absence of the supply of waste liquid to the second combustion furnace. can do. Thereby, the structure which suppresses the fall of the processing amount of a waste liquid according to the presence or absence of supply of a waste liquid is easily realizable.

  The waste liquid treatment apparatus of the present invention further includes a cooling device that cools the exhaust gas by spraying water on the exhaust gas discharged from the second combustion furnace, and the second set temperature and the second combustion furnace When the waste liquid is supplied, the second set temperature is set so that the temperature difference from the temperature in the second combustion furnace realized by controlling the set temperature to the first set temperature is within a threshold value. A predetermined spray amount corresponding to the temperature in the second combustion furnace is controlled and sprayed from the cooling device.

  According to such a waste liquid treatment apparatus, when the waste liquid is not supplied to the second combustion furnace, the set temperature is limited to the second set temperature, and the amount of generated heat in the first combustion furnace is suppressed. Since the suppressed amount of heat is postponed to the next waste liquid incineration process, the combustion time per batch becomes longer, but by controlling the set temperature of the first combustion furnace to the second set temperature, the combustion exhaust is reduced. It is possible to reduce the required amount of cooling water required for setting the temperature to a predetermined temperature or lower.

  Further, the temperature difference between the second set temperature and the temperature of the second combustion furnace realized by the first set temperature is a constant temperature difference, so that the exhaust temperature is maintained within a predetermined temperature range. Thus, the amount of cooling water required to cool the exhaust gas can be quantified. As a result, the total amount of cooling water required for cooling can be reduced, and waste liquid can be treated efficiently while saving the cost for cooling the exhaust.

  In order to achieve the above object, the present invention is a waste liquid treatment method for incinerating a plurality of waste liquids, igniting the waste contained in a dry distillation furnace, and burning a part of the waste, A step of dry-distilling the other part of the waste with combustion heat, a step of introducing a combustible gas generated by the dry distillation into the first combustion furnace for combustion, and a second combustion of the combustion heat of the first combustion furnace And a step of incinerating the waste liquid supplied to the second combustion furnace, and is introduced into the first combustion furnace when the combustible gas is burned in the first combustion furnace. According to the amount of combustible gas, oxygen required for combustion is supplied to the combustion furnace to burn the combustible gas, and the temperature in the combustion furnace due to combustion of the combustible gas in the first combustion furnace Combustibility generated by dry distillation by controlling the amount of oxygen supplied to the dry distillation furnace according to changes A step of supplying one of the plurality of waste liquids to the second combustion furnace in a combustion operation of adjusting the amount of gas and maintaining the temperature in the first combustion furnace at a set temperature; In the step of supplying waste liquid to the second incinerator when repeatedly performing the step of supplying the second combustion furnace to the second combustion furnace and the standby step of providing a constant time interval between the two steps. The set temperature is controlled to the first temperature so that the temperature in the furnace becomes equal to or higher than the temperature at which dioxins can be thermally decomposed. In the standby step, the temperature in the first combustion furnace is reduced to the thermal decomposition of dioxins. The set temperature is controlled to a second set temperature that is set to the lower temperature region side in a temperature range that is higher than a possible temperature and that maintains self-combustion.

  According to the waste liquid treatment method of the present invention, in a dry distillation gasification incineration apparatus for combusting a combustible gas introduced from a dry distillation furnace in a first combustion furnace, a second combustion furnace in which combustion heat is introduced from the first combustion furnace. Repeatedly execute a series of processes consisting of a process of supplying one waste liquid to incineration, a process of supplying other waste liquid and processing, and a standby process with a certain time interval between these processes In doing so, the set temperature of the first combustion furnace in each step is controlled as follows.

  That is, in the process of supplying the waste liquid to the second incinerator, the temperature of the second combustion furnace is lowered due to the heat of vaporization of the supplied waste liquid. Therefore, the set temperature is controlled to the first set temperature so that the temperature in the second combustion furnace becomes equal to or higher than the temperature at which dioxins can be thermally decomposed. Therefore, the first set temperature can be set to a temperature suitable for the incineration treatment of the waste liquid while preventing the discharge of dioxins due to the incineration treatment of the waste, and the waste liquid can be processed efficiently.

  On the other hand, in the standby process, since the waste liquid is not supplied, the temperature drop in the second combustion furnace hardly occurs, so that the set temperature can be lowered as compared with the case where the waste liquid is supplied. Here, the temperature in the first combustion furnace is (1) maintained at a temperature higher than the temperature at which dioxins can be thermally decomposed, and (2) a temperature at which self-combustion is maintained even when the set temperature is lowered. There is a need to. Therefore, the set temperature is controlled to the second set temperature set on the low temperature region side within the range satisfying the conditions (1) and (2).

  The combustion heat generated in the first combustion furnace while the waste liquid is not being supplied to the second combustion furnace is not used for the treatment of the waste liquid and causes a reduction in the processing amount of the waste liquid. By setting the temperature to a lower temperature within the range satisfying the conditions (1) and (2), it is possible to suppress the generation of combustion heat that is not used for waste liquid treatment. Then, when the waste liquid is supplied next time, the suppressed amount of combustion heat can be generated and used for the treatment of the waste liquid.

  As described above, according to the waste liquid treatment method of the present invention, when a plurality of waste liquids are incinerated in the dry distillation gasification incineration processing apparatus, the waste liquid can be efficiently processed while suppressing a decrease in the processing amount.

The system block diagram which shows one Embodiment of the waste-liquid processing apparatus of this invention. The graph which shows the time-dependent change of the combustion temperature in a 1st and 2nd combustion furnace, the supply amount of a waste liquid, and the supply amount of cooling water.

  Next, the embodiment of the present invention will be described in more detail with reference to FIG. 1 and FIG. FIG. 1 is a system configuration diagram showing an embodiment of the waste liquid treatment apparatus of the present invention, and FIG. 2 is a diagram showing the combustion temperature and waste liquid in the first and second combustion furnaces in the waste liquid treatment method by the apparatus of this embodiment. It is a graph which shows the time-dependent change of the supply amount and the supply amount of cooling water.

  As shown in FIG. 1, the waste liquid treatment apparatus of the present embodiment includes a dry distillation furnace 1 containing waste A, which is a mixture of various wastes mainly industrial waste, and gas in the dry distillation furnace 1. A first combustion furnace 3 connected via a passage 2 and a second combustion furnace 4 connected to the first combustion furnace 3 are provided. The top surface of the dry distillation furnace 1 is formed with a charge opening 5b having a chargeable door 5a that can be opened and closed, and the waste A can be charged into the dry distillation furnace 1 from the charge opening 5b. In the state where the charging door 5a is closed, the inside of the dry distillation furnace 1 is substantially cut off from the outside.

  A water jacket 6 isolated from the inside of the dry distillation furnace 1 is formed on the outer peripheral portion of the dry distillation furnace 1 as a cooling structure. The water jacket 6 is supplied with water by a water supply device (not shown) so that the amount of water inside is maintained at a predetermined water level.

  An ash outlet 7b having an openable and closable ash exit door 7a is formed at the lower part of the dry distillation furnace 1, and the ash after burning waste in the dry distillation furnace 1 can be discharged from the ash outlet 7b. When the charging door 5a and the ash door 7a are closed, the inside of the dry distillation furnace 1 is substantially cut off from the outside air.

  The ash exit door 7a is formed with an empty space 8a that is isolated from the inside of the dry distillation furnace 1. This empty room 8 a communicates with the inside of the dry distillation furnace 1 through a plurality of air supply nozzles 8 b provided on the inner wall of the dry distillation furnace 1. A dry oxygen supply path 9 is connected to the vacant chamber 8a. The dry distillation oxygen supply path 9 is connected via a main oxygen supply path 10 to an oxygen (air) supply source 11 constituted by a pushing fan or the like. A control valve 12 is provided in the dry distillation oxygen supply path 9, and the opening degree of the control valve 12 is controlled by a valve driver 13. In this case, the valve driver 13 is controlled by a control device 14 configured by an electronic circuit including a CPU and the like.

  Furthermore, an ignition device 15 for igniting the waste A stored in the dry distillation furnace 1 under the control of the control device 14 is attached to the lower portion of the dry distillation furnace 1. The ignition device 15 is composed of an ignition burner or the like, and supplies a combustion flame to the waste A by burning the fuel supplied from the fuel supply device 16 in which fuel such as heavy oil is stored through the fuel supply path 17. To do.

  The first combustion furnace 3 includes a burner unit 18 that mixes combustible gas generated by dry distillation of waste A and oxygen (air) necessary for complete combustion, and a combustion unit that combusts the combustible gas mixed with oxygen. 19, and the combustion part 19 communicates with the burner part 18 on the tip end side of the burner part 18. The gas passage 2 is connected to the rear end portion of the burner portion 18, and combustible gas generated by the dry distillation of the waste A in the dry distillation furnace 1 is introduced into the burner portion 18 through the gas passage 2.

  A vacant chamber 20 isolated from the inside of the burner portion 18 is formed on the outer peripheral portion of the burner portion 18, and the vacant chamber 20 is inserted into the burner portion 18 through a plurality of nozzle holes 21 formed in the inner peripheral portion of the burner portion 18. It communicates with the inside. A combustion oxygen supply path 22 branched from the main oxygen supply path 10 is connected to the vacant chamber 20. The combustion oxygen supply passage 22 is provided with a control valve 23, and the opening degree of the control valve 23 is controlled by a valve driver 24 driven by the control device 14.

  A combustion device 25 that is controlled by the control device 14 and burns fuel such as heavy oil supplied from the fuel supply device 16 via the fuel supply path 17 is attached to the rear end portion of the burner portion 18. The combustion device 25 is composed of an ignition burner or the like, and burns while adjusting the fuel supply amount stepwise. The combustion device 25 is also used when igniting the combustible gas introduced into the burner unit 18.

  The second combustion furnace 4 has a waste liquid nozzle 26 for spraying the waste liquid B, a waste oil nozzle 27 for spraying the waste oil C, and a combustion device 28 attached to the upper part of an upright cylindrical furnace body. Of the first combustion furnace 3 and below the waste liquid nozzle 26 and the waste oil nozzle 27.

  The waste liquid nozzle 26 is connected to a waste liquid supply path 29, and the waste liquid supply path 29 is connected to a waste liquid supply source 30 including a plurality of waste liquid tanks 30a to 30c (corresponding to the waste liquid storage means of the present invention). . Control valves 31 a to 31 c are respectively provided between the waste liquid tanks 30 a to 30 c and the waste liquid supply passage 29, and the control valves 31 a to 31 c are controlled to be opened and closed by the control device 14. In each of the waste liquid tanks 30a to 30c, a plurality of types of waste liquid (for example, photographic developing waste liquid, sodium silicate waste liquid, photographic bleaching waste liquid, etc.) are stored without being mixed. The waste liquid stored in each of the waste liquid tanks 30 a to 30 c is compressed and supplied to the waste liquid nozzle 26 by an air compressor (not shown), so that the waste liquid is atomized and sprayed into the second combustion furnace 4.

  The waste oil nozzle 27 is connected to a waste oil supply path 32, and the waste oil supply path 32 is connected to a waste oil supply source 33 including a plurality of waste oil tanks 33a and 33b. Control valves 34a and 34b are provided between the waste oil tanks 33a and 33b and the waste oil supply path 32, respectively, and the opening and closing of the control valves 34a and 34b are controlled by the control device 14. In each of the waste oil tanks 33a and 33b, a plurality of types of waste oil (for example, lubricating oil-based waste liquid and hydraulic oil-based waste liquid) are stored without being mixed. The waste oil stored in each of the waste oil tanks 33a and 33b is compressed and supplied to the waste oil nozzle 27 by an air compressor (not shown), so that the waste oil is atomized and sprayed into the second combustion furnace 4.

  The combustion device 28 is configured by an ignition burner or the like, and burns fuel such as heavy oil supplied from the fuel supply device 16 via the fuel supply path 17 under the control of the control device 14.

  A cooling furnace 35 for cooling the combustion exhaust of the first combustion furnace 3 and the second combustion furnace 4 is attached to the lower side of the furnace body of the second combustion furnace 4 via a duct 34a. The cooling furnace 35 is supplied with water by a water supply device (not shown), and hot water heated in the cooling furnace 35 using the combustion heat of waste can be used for air conditioning or the like.

  One end of a cooling tower 36 is connected to the outlet side of the cooling furnace 35 through a duct 34 b, and the cooling tower 36 includes a spray 37 that sprinkles the combustion exhaust from the cooling furnace 35. Cooling water stored in the cooling water tank 38 is supplied to the spray 37 by a water supply device and an air compressor (not shown).

  The other end of the cooling tower 36 is connected to one end of a bag filter 39 through a duct 34c. The combustion exhaust sent from the cooling tower 36 to the bag filter 39 is supplied with slaked lime and activated carbon from the chemical silo 40. Are configured to be mixable.

  The bag filter 39 includes a filter unit (not shown) and a recovery unit that recovers ash and the like separated from the exhaust gas by the filter unit, and an air compressor (not shown) for cleaning is connected to the filter unit. Yes.

  The other end of the bag filter 39 is connected to a desulfurization device 41 via a duct 34d. The duct 34d attracts combustion exhaust gas from the first combustion furnace 3 and the second combustion furnace 4 to the desulfurization device 41. An attracting fan 42 is provided.

  The desulfurization apparatus 41 includes, for example, a packed bed 43 filled with a plurality of polypropylene hollow spiral fillers, and a caustic soda reservoir 44 in which a caustic soda aqueous solution is stored below the packed bed 43, and combustion supplied from a duct 34d Exhaust gas is introduced into the desulfurization apparatus 41 through an introduction path 45 provided between the packed bed 43 and the caustic soda reservoir 44.

  The aqueous solution of caustic soda stored in the caustic soda reservoir 44 is sprayed from the plurality of nozzles 47a and 47b provided above the introduction path 45 and the packed bed 43 by the circulation pump 46, and the dispersed caustic soda aqueous solution is again stored in the caustic soda by its own weight. It returns to the part 44. Further, the caustic soda storage unit 44 can be supplied with water by a water supply device (not shown) and is supplied with caustic soda from the caustic soda tank 48 according to the PH value of the stored caustic soda aqueous solution. Further, a part of the caustic soda aqueous solution stored in the caustic soda storage unit 44 is introduced into the cooling water tank 38 through the water supply pipe 49.

  The combustion exhaust gas introduced into the desulfurization device 41 passes through the packed bed 43 and is discharged into the atmosphere from the chimney 50 connected to the upper portion of the desulfurization device 41.

  Further, in the apparatus of the present embodiment, a temperature sensor 51 for detecting the temperature T1 in the furnace is attached to the first combustion furnace 3, and a temperature for detecting the temperature T2 in the furnace is installed below the second combustion furnace 4. A sensor 52 is attached. Detection signals from the temperature sensors 51 and 52 are input to the control device 14. A temperature sensor 53 for detecting the temperature of the combustion exhaust gas in the duct 34 c is attached to the duct 34 c on the downstream side of the cooling tower 37, and sprayed from the spray 37 based on the temperature detected by the temperature sensor 53. The amount of cooling water is adjusted by the control valve 54.

  Next, a waste liquid treatment method using the apparatus of this embodiment will be described with reference to FIGS. 1 and 2.

  In the apparatus shown in FIG. 1, first, the charging door 5a of the dry distillation furnace 1 is opened, and the waste A is supplied into the dry distillation furnace 1 from the charging opening 5b. The waste A is a mixture of various wastes, mainly medical waste, and the combustion temperature is 800 ° C. or higher when the combustible gas generated by the dry distillation in the dry distillation furnace 1 is stably burned. It is adjusted to have the amount of heat to become.

Next, after closing the charging door 5a and sealing the inside of the dry distillation furnace 1, the combustion device 25 of the first combustion furnace 3 is combusted by the control device 14 prior to the ignition of the waste A, thereby Start warm-up operation by burning fuel. Specifically, in the graph showing the time change shown in FIG. 2, the combustion of the fuel is started at time t _0.

Then, the temperature T1 in the first combustion furnace 3 rises gradually by the combustion of the fuel, at time t ₁ the temperature T1 detected by the temperature sensor 51, the 800 ° C. being possible pyrolysis of dioxins When it reaches, the controller 14 activates the ignition device 15 of the dry distillation furnace 1 to ignite the waste A. Then, after time t ₁ , in the first combustion furnace 3, an auxiliary combustion operation is started in which combustible gas generated by partial combustion of the waste A is combusted in the first combustion furnace 3 together with the fuel.

Then, the temperature T1 in the first combustion furnace 3 rises with increasing amount of generated combustible gas, also to stop combustion of the fuel by the combustion device 25 at time t _2, the first combustion furnace 3 If the temperature T1 is maintained at a predetermined temperature (for example, 835 ° C.) or higher, the control device 14 assumes that the combustible gas has reached a state where it can be spontaneously combusted by its own combustion heat. Finish burning.

On the other hand, the temperature T2 of the second combustion furnace 4 is gradually increased from the time t ₀ by the combustion heat of the warm-up operation by the combustion device 25 of the first combustion furnace 3, the time t ₁ after the combustion heat of the flammable gas Combined with further rise. Then, the time to reach the time t _2, the temperature T2 of the second combustion furnace 4 is substantially equal to the temperature T1 of the first combustion furnace 3.

Therefore, the control unit 14, at time t _2, the waste of the control valve 31a is gradually opened to start supplying the waste liquid to the waste liquid supply path 29 from one of the waste tank 30a of the waste liquid source 30 (the present invention Corresponds to the step of supplying). The waste liquid supplied to the waste liquid supply path 29 is sprayed into the furnace from the waste liquid nozzle 26 in the upper part of the second combustion furnace 4. At this time, the temperature T2 in the second combustion furnace 4 temporarily decreases due to the heat of vaporization of the sprayed waste liquid, but the control device 14 monitors the temperature T2 in the second combustion furnace 4 to Control is performed so that the opening degree of the control valve 31a is increased in synchronization with the temperature increase of the temperature T1 in the first combustion furnace 3 on condition that T2 does not fall below a predetermined temperature (for example, 830 ° C.).

Time t ₂ later, in the first combustion furnace 3, the spontaneous combustion of only the combustible gas is performed, the temperature T1 in the first combustion furnace 3 detected by the temperature sensor 51 is substantially combustible gas itself It shows the combustion temperature of. When spontaneous combustion of only the combustible gas is performed, the combustion temperature of the combustible gas itself detected by the temperature T1 in the first combustion furnace 3 increases with an increase in the amount of combustible gas generated. It rises and, at time t ₃ reaches the first set temperature set as the target temperature (the maximum setting temperature Tmax). The first set temperature is a temperature of 800 ° C. or higher, which is a temperature at which dioxins can be thermally decomposed, and is set to an optimum temperature from the amount of waste liquid to be incinerated and the processing efficiency. At this time, in synchronization with the temperature T1 in the first combustion furnace 3 reaching the target temperature, the control device 14 controls the control valve 31a and the amount of waste liquid supplied from the waste liquid tank 30a to the waste liquid nozzle 26. Is the maximum supply amount FLmax.

Then, a time t ₃ after, the temperature T1 in the first combustion furnace 3 is maintained at a substantially constant temperature of the first set temperature Tmax, the supply amount of the waste liquid which is sprayed into the second combustion furnace 4 is maximum supply amount FLmax Maintained.

  At this time, the control device 14 automatically controls the opening degree of the control valve 23 of the combustion oxygen supply passage 22 so that a sufficient amount of oxygen necessary for complete combustion of the combustible gas is supplied to the burner unit 18. To do. At the same time, the control device 14 automatically controls the opening degree of the control valve 12 according to the combustion temperature T1 of the combustible gas in the first combustion furnace 3 detected by the temperature sensor 51, so that the The generation amount of the combustible gas is adjusted so that the combustion temperature T1 of the combustible gas in the first combustion furnace 3 is maintained substantially constant at the first set temperature Tmax.

  Next, a description will be given of the standby process for giving a certain time interval in order to end the processing of the waste liquid stored in the waste liquid tank 30a and start the processing of the waste liquid stored in the waste liquid tank 30b.

At time t _4, the control device 14, the indicated value of the (not shown) installed in the waste tank 30a level gauge is 0, as the supply of waste liquid from the waste liquid tank 30a is completed, the first combustion furnace 3 Is changed from the first set temperature T1max to the second set temperature T1min. The second set temperature T1min is set to the low temperature region side in a temperature range in which (1) the temperature at which dioxins can be thermally decomposed is 800 ° C. or higher and (2) self-combustion by the combustible gas is maintained. The temperature at which self-combustion is maintained is a design value for an incinerator determined based on the volume of the dry distillation furnace 1 and the first combustion furnace 3 and the like.

  Here, as long as the second set temperature T1min is a value satisfying the above conditions (1) and (2), the generation of combustion heat in the standby process can be suppressed as the temperature is set lower. That is, by controlling the second preset temperature as low as possible, the amount of combustible gas generated in the dry distillation furnace 1 is suppressed so that the temperature T1 in the first combustion furnace 3 becomes the second preset temperature T1min. The Then, when the waste liquid is supplied next time, the combustible gas corresponding to the generation is suppressed, and the combustion heat can be used for the treatment of the waste liquid. Therefore, in the present embodiment, the second set temperature T1min is set to the lowest temperature that satisfies the above conditions (1) and (2).

At time t _4, when the set temperature of the first combustion furnace 3 is changed to the second set temperature T1min, the control unit 14, by limiting the degree of opening of the control valve 12, the combustible gas in the dry distillation furnace 1 Is controlled such that the combustion temperature T1 of the combustible gas in the first combustion furnace 3 becomes the second set temperature Tmin. By this control, the temperature T1 in the first combustion furnace 3 is gently lowered from time t _4, it is maintained substantially constant in the second set temperature Tmin.

On the other hand, the temperature T2 of the second combustion furnace 4, at time t _4, but temporarily temperature eliminates the consumption of the vaporization heat of the waste liquid is increased, then the temperature drop in the first combustion furnace 3, the waste liquid supply It is maintained at a temperature almost equal to the time.

  In such a standby process, water is supplied from a water supply device (not shown) into the waste liquid tank 30a after the supply of the waste liquid, and the waste liquid supply path 29 is washed away. This series of operations is intended to prevent the reaction between the waste liquid that has already been processed and the waste liquid to be processed next in the waste liquid supply path 29 and the reaction between adsorbates in the bag filter 39. It takes about 30 minutes. In the case where the same waste liquid is supplied from another waste liquid tank 30b, it can be omitted.

  In a specific comparative experiment conducted by the inventor of the present application, when the standby temperature is changed to the second set temperature T1min, the temperature T1 in the first combustion furnace 3 is set to the first temperature as shown by the phantom line in the figure. It has been found that the waste liquid treatment time is increased by about 20 minutes as compared with the case where the set temperature T1max is maintained.

  Next, a process of supplying the waste liquid from the waste liquid tank 30b in which different waste liquids are stored and performing incineration processing will be described.

At time t _5, when the washing flow operations of the waste liquid supply path 29 is completed, the control unit 14 changes the set temperature of the first combustion furnace 3 from the second set temperature T1min in the first set temperature Tmax. Accordingly, the control device 14 adjusts the opening degree of the control valve 12, sets the amount of combustible gas generated in the dry distillation furnace 1, and sets the combustion temperature T1 of the combustible gas in the first combustion furnace 3 to the first setting. The temperature is controlled to be Tmax. By this control, the temperature T1 in the first combustion furnace 3 rises from time t _5.

At this time, the control unit 14 at time t _5, closes the control valve 31a, the control valve 31b is gradually opened to start the supply of the waste liquid from the waste liquid tank 30b into the waste supply passage 29 (liquid waste of the present invention Is equivalent to the step of supplying The waste liquid supplied to the waste liquid supply path 29 is sprayed into the furnace from the waste liquid nozzle 26 in the upper part of the second combustion furnace 4. Although the temperature T2 in the second combustion furnace 4 temporarily decreases due to the vaporization heat of the sprayed waste liquid, the control device 14 monitors the temperature T2 in the second combustion furnace 4 and the temperature T2 is Control is performed to increase the opening of the control valve 31b in synchronism with the temperature rise of the temperature T1 in the first combustion furnace 3 on condition that the temperature does not fall below a predetermined temperature (for example, 830 ° C.).

Then, at time t _6, the temperature T1 in the first combustion furnace 3 is in synchronism with reaching the first predetermined temperature T1max, the control device 14 controls the control valve 31b, the waste liquid nozzle from the waste liquid tank 30b The amount of waste liquid supplied to 26 is again set to the maximum supply amount FLmax. Time t ₆ and later kept at the temperature T1 in the first combustion furnace 3 is maintained at a substantially constant temperature of the first set temperature Tmax, the supply amount of the waste liquid which is sprayed into the second combustion furnace 4 is maximum supply amount FLmax Is done.

  The above is the description of the change with time of the combustion temperature in the first combustion furnace 3 and the second combustion furnace 4 and the supply amount of the waste liquid in the waste liquid treatment method of the present embodiment.

  Next, changes with time of the cooling water supplied to the cooling tower 36 will be described with reference to the lower part of FIG.

When the temperature in the first combustion furnace 3 and the second combustion furnace 4 rises from the time t ₀ due to the combustion heat in the warm air operation, the temperature of the combustion exhaust gas introduced into the cooling tower 36 also rises accordingly. Then, when the temperature sensor 53 installed on the downstream side of the cooling tower 36 reaches a predetermined temperature, supply of cooling water to the spray 37 is started. The supply start temperature of the cooling water based on the temperature sensor 53 is set on the assumption that the combustion exhaust when the temperature T1 in the first combustion furnace 4 reaches 800 ° C. is introduced into the cooling tower 36. . Therefore, the supply of cooling water to the spray 37, starting from approximately time t _1.

The amount of cooling water sprayed from the spray 37 is controlled based on the temperature detected by the temperature sensor 53. Therefore, the supply amount of the cooling water increases with the temperature of the combustion exhaust gas introduced into the cooling tower 36. Then, a time t ₂ later, when the temperature T2 of the second combustion furnace 4 is stabilized, the supply amount of the cooling water is maintained at a substantially constant value.

Next, the supply amount of the cooling water in the standby process will be described. At time t _4, when the processing of the waste liquid is completed, the temperature T2 of the second combustion furnace 4 with to temporarily increase, also temporarily increases the supply amount of the cooling water. Thereafter, as the temperatures T1 and T2 in the first combustion furnace 3 and the second combustion furnace 4 decrease, the supply amount of the cooling water is also maintained at a value substantially equal to that at the time of waste liquid supply.

  In a specific comparative experiment conducted by the inventor of the present application, when the standby temperature is changed to the second set temperature T1min, the temperature T1 in the first combustion furnace 3 is set to the first temperature as shown by the phantom line in the figure. Compared to the case where the set temperature T1max is maintained, the supply amount of the cooling water can be reduced to about ½.

  Thus, in the standby step, by changing the set temperature from the first set temperature Tmax to the second set temperature Tmin, as described above, the combustion time per batch of the dry distillation furnace becomes longer, but the second set temperature is set. By making the temperature difference between Tmin and the temperature T2 of the second combustion furnace realized by the first set temperature Tmax a constant temperature difference, the exhaust gas temperature is maintained within a predetermined temperature range, and the exhaust gas temperature The amount of the aqueous solution necessary for cooling the water can be set to a substantially constant value. Therefore, it is possible to reduce the amount of cooling water required to reduce the combustion exhaust to a predetermined temperature (for example, 200 ° C.) or less, and to reduce the total amount of cooling water required for cooling. As a result, the amount of cooling water consumed only for cooling can be reduced, and the required cooling water can be substantially provided by the aqueous solution introduced from the caustic soda tank 48 to the cooling water tank 38, thereby cooling the exhaust. It is possible to save costs. Further, by reducing the total amount of cooling water, corrosion of the cooling tower 36 and the downstream side duct 34c due to sodium sulfite, sodium chloride components and the like contained in the cooling water can be suppressed.

Then, at time t _5, when the different waste fluid is supplied, as the temporary reduction in the temperature T2 of the second combustion furnace 4, the supply amount of the cooling water is temporarily increased, then When the temperature T2 in the second combustion furnace 4 is stabilized, the supply amount of the cooling water is maintained at a substantially constant value.

  As described above in detail, according to the waste liquid treatment apparatus of the present embodiment, when incinerating a plurality of waste liquids in the dry distillation gasification incineration treatment apparatus, the waste liquid is efficiently treated while suppressing a reduction in the processing amount. be able to.

  In addition, although this embodiment demonstrated the case where the supply source of the exhaust_gas | exhaustion supplied by one waiting | standby process was switched from the waste liquid tank 30a to the waste liquid tank 30b, during the processing time per batch of the dry distillation furnace 1, it is several. A plurality of waste liquids may be switched in order by leaving the standby process. In this case, the generation of combustion heat that is not used for waste liquid treatment is suppressed by the number of standby steps, and when the waste liquid is supplied next time, the amount of combustion heat that is suppressed is generated and combustion per batch is performed. Time can be extended and used for waste liquid treatment.

In the present embodiment, the case of processing the waste liquid has been described. However, instead of the waste liquid, the waste oil stored in the waste oil tanks 33a and 33b is supplied to the waste oil nozzle 27 via the waste oil supply path 32 and incinerated. May be. At this time, since the waste oil does not react even when mixed with other waste oil or waste liquid, a plurality of waste oils may be mixed and supplied via the control valves 34a and 34b.
Further, one or a plurality of waste oils and a single waste liquid may be mixed and supplied via the control valve 31a and the control valves 34a and 34b. In addition, when supplying waste oil to the 2nd combustion furnace 4, since the temperature of the 2nd combustion furnace 4 can rise with the combustion heat of waste oil compared with the incineration process of waste liquid, this 1st preset temperature is implemented. It is desirable to set a value lower than Tmax of the form.

DESCRIPTION OF SYMBOLS 1 ... Dry distillation furnace, 3 ... 1st combustion furnace, 4 ... 2nd combustion furnace, 12 ... Control valve (dry distillation oxygen supply means), 14 ... Control apparatus, 23 ... Control valve (combustion oxygen supply means), 30a-30c ... Waste liquid tank (waste liquid storage means), 31a to 31c ... control valve (supply means), 37 ... cooling tower (cooling device), 41 ... desulfurization device.

Claims (4)

A waste liquid treatment apparatus that incinerates a plurality of waste liquids,
A combustible gas for storing combustible gas and combusting a part of the combustible material to dry the remainder of the combustible material to produce combustible gas, and combustible gas introduced from the combustible gas furnace A first combustion furnace for burning the gas, a combustion oxygen supply means for supplying oxygen required for the combustion to the first combustion furnace according to the amount of combustible gas introduced into the first combustion furnace, and the first combustion furnace A first temperature detecting means for detecting the temperature inside the first combustion furnace, and a temperature in the first combustion furnace detected by the first temperature detecting means after the combustion of the combustible gas in the first combustion furnace is started. A distillation oxygen supply means for adjusting the oxygen supply amount to the first distillation furnace so as to maintain the temperature, and the waste liquid by the combustion heat introduced from the first combustion furnace connected to the first combustion furnace. A second combustion furnace for incineration, and waste for supplying the waste liquid to the second combustion furnace Comprising a feed means, and a second temperature sensing means for sensing the temperature in the second combustion furnace,
When waste liquid is supplied to the second combustion furnace, the temperature in the second combustion furnace detected by the second temperature detection means is equal to or higher than the temperature at which dioxins can be thermally decomposed. When the set temperature is controlled to the first set temperature and no waste liquid is supplied to the second combustion furnace, the temperature in the first combustion furnace detected by the first temperature detecting means is the dioxin level. A waste liquid treatment apparatus, characterized in that the set temperature is controlled to a second set temperature that is set to a lower temperature range in a temperature range that is equal to or higher than a temperature at which pyrolysis is possible and that maintains self-combustion. The waste liquid treatment apparatus according to claim 1,
A plurality of waste liquid storage means for storing the waste liquid, and a supply means for supplying the waste liquid from each waste liquid storage means to the second combustion furnace,
When the waste liquid is supplied by the supply means, the set temperature is controlled to the first set temperature, and when the waste liquid is not supplied by the supply means, the set temperature is set to the second temperature. A waste liquid treatment apparatus that is controlled to a set temperature. In the waste liquid processing apparatus according to claim 1 or 2,
A cooling device for cooling the exhaust gas by spraying water on the exhaust gas discharged from the second combustion furnace,
A temperature difference between the second set temperature and a temperature in the second combustion furnace realized by controlling the set temperature to the first set temperature when waste liquid is supplied to the second combustion furnace. The waste liquid treatment apparatus is characterized in that the second set temperature is controlled so that the value falls within a threshold value, and a predetermined spray amount corresponding to the temperature in the second combustion furnace is sprayed from the cooling device. A waste liquid treatment method for incinerating a plurality of waste liquids,
A step of igniting the waste contained in the dry distillation furnace to combust a part of the waste and subjecting the other part of the waste to dry distillation by the heat of combustion, and a combustible gas generated by the dry distillation to the first Introducing into the combustion furnace and burning, and introducing the combustion heat of the first combustion furnace into the second combustion furnace to incinerate the waste liquid supplied to the second combustion furnace, When combustible gas is burned in the first combustion furnace, oxygen required for the combustion is supplied to the combustion furnace according to the amount of combustible gas introduced into the first combustion furnace, and the combustible gas is The amount of combustible gas generated by the dry distillation is controlled by controlling the amount of oxygen supplied to the dry distillation furnace according to the temperature change in the combustion furnace due to the combustion of the combustible gas in the first combustion furnace. In the combustion operation to adjust and maintain the temperature in the first combustion furnace at the set temperature,
A step of supplying one of the plurality of waste liquids to the second combustion furnace, a step of supplying another waste liquid to the second combustion furnace, and a standby step of providing a constant time interval between the two processes When repeatedly executing
In the step of supplying the waste liquid to the second incinerator, the set temperature is controlled to the first temperature so that the temperature in the second combustion furnace is equal to or higher than the temperature at which dioxins can be thermally decomposed,
In the standby step, the temperature in the first combustion furnace is equal to or higher than a temperature at which dioxins can be thermally decomposed and is set to a second set temperature that is set to a lower temperature range in a temperature range in which self-combustion is maintained. A waste liquid treatment method characterized by controlling temperature.

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