JP7550445B2 - Dry distillation gasification incineration treatment equipment - Google Patents

Description

The present invention relates to a dry distillation, gasification and incineration treatment device that dry distills and incinerates waste materials such as scrap tires.

As an apparatus for incinerating waste materials such as scrap tires, for example, a dry distillation gasification incineration treatment apparatus is known, which burns a portion of the waste stored in a dry distillation furnace, dry distills (pyrolyzes) the remainder of the waste using the heat of combustion, and introduces the combustible gas produced by the dry distillation from the dry distillation furnace into a combustion furnace for combustion (see, for example, Patent Document 1).

In the dry distillation gasification incineration treatment device described in Patent Document 1, when hydrogen chloride is contained in the exhaust gas burned in the combustion furnace, the hydrogen chloride concentration of the exhaust gas is neutralized in a neutralization device to a specified value or less before being released into the atmosphere.

Japanese Patent Application Publication No. 2-135280

However, in the dry distillation gasification incineration treatment device described in Patent Document 1, if the combustion exhaust contains hydrogen chloride at a concentration that exceeds the neutralization capacity of the neutralization device, the hydrogen chloride concentration in the combustion exhaust exceeds the specified value even after neutralization, so it is necessary to stop the operation of the dry distillation gasification incineration treatment device.

The present invention was made in light of this background, and aims to provide a dry distillation gasification incineration treatment device that can be operated continuously while maintaining the hydrogen chloride concentration at or below a specified value.

[1] A dry distillation gasification incineration treatment apparatus comprising: a dry distillation furnace for storing waste and combusting a portion of the waste while dry distilling the remainder of the waste using the combustion heat to generate a combustible gas; a combustion furnace for combusting the combustible gas supplied from the dry distillation furnace; a dry distillation oxygen supply means for supplying oxygen required for combustion of a portion of the waste in the dry distillation furnace via a dry distillation oxygen supply line to the dry distillation furnace; a combustion oxygen supply means for supplying oxygen required for combustion of the combustible gas introduced into the combustion furnace to the combustion furnace; and a dry distillation furnace valve provided in the dry distillation oxygen supply line for adjusting the oxygen supplied to the dry distillation furnace,
a hydrogen chloride concentration detection means for detecting the hydrogen chloride concentration of the combustion exhaust gas discharged from the combustion furnace;
a control means for controlling a temperature of the combustion furnace by driving the dry distillation furnace valve to adjust the amount of air supplied to the dry distillation furnace based on the concentration detected by the hydrogen chloride concentration detection means;
A dry distillation gasification incineration treatment device comprising:

According to the present invention, the control means controls the temperature of the combustion furnace by driving the furnace valve to adjust the amount of air supplied to the furnace based on the concentration detected by the hydrogen chloride concentration detection means, so that the concentration detected by the hydrogen chloride concentration detection means can be kept below a specified value by controlling the temperature of the combustion furnace.

[2] A neutralization means for neutralizing hydrogen chloride in the combustion exhaust gas discharged from the combustion furnace is provided,
the hydrogen chloride concentration detection means detects the hydrogen chloride concentration of the combustion exhaust gas after neutralization by the neutralization means,
It is preferable that when the neutralization capacity of the neutralization means reaches its maximum, the control means reduces the temperature of the combustion furnace by reducing the opening of the dry distillation furnace valve and decreasing the amount of air supplied to the dry distillation furnace based on the concentration detected by the hydrogen chloride concentration detection means.

According to the above configuration, the hydrogen chloride concentration in the combustion exhaust can be reduced by neutralizing the hydrogen chloride (hydrogen chloride gas) in the combustion exhaust with the neutralization means. Furthermore, when the neutralization capacity of the neutralization means is maximized, the opening of the dry distillation furnace valve is reduced based on the concentration detected by the hydrogen chloride concentration detection means to reduce the amount of air supplied to the dry distillation furnace and lower the temperature of the combustion furnace, thereby reducing the hydrogen chloride concentration accordingly. This makes it possible to prevent the concentration detected by the hydrogen chloride concentration detection means from exceeding a specified value.

[3] When the concentration detected by the hydrogen chloride concentration detection means exceeds a first predetermined concentration, the control means preferably reduces the opening of the dry distillation furnace valve to a first opening to reduce the amount of air supplied to the dry distillation furnace, thereby reducing the temperature of the combustion furnace to a first predetermined temperature.

According to the above configuration, when the concentration detected by the hydrogen chloride concentration detection means exceeds the first predetermined concentration, the opening of the dry distillation furnace valve is lowered to the first opening to reduce the amount of air supplied to the dry distillation furnace, thereby lowering the temperature of the combustion furnace to the first predetermined temperature, and the hydrogen chloride concentration can be lowered accordingly. This allows the concentration detected by the hydrogen chloride concentration detection means to be equal to or lower than the first predetermined concentration.

[4] When the concentration detected by the hydrogen chloride concentration detection means does not become equal to or lower than the first predetermined concentration even if the temperature of the combustion furnace is lowered to the first predetermined temperature, but exceeds a second predetermined concentration higher than the first predetermined concentration, the control means preferably lowers the temperature of the combustion furnace to a second predetermined temperature lower than the first predetermined temperature by lowering the aperture of the dry distillation furnace valve to a second aperture lower than the first aperture to reduce the amount of air supplied to the dry distillation furnace.

According to the above configuration, when the concentration detected by the hydrogen chloride concentration detection means does not become equal to or lower than the first predetermined concentration even when the temperature of the combustion furnace is lowered to the first predetermined temperature, but exceeds a second predetermined concentration higher than the first predetermined concentration, the control means lowers the opening of the dry distillation furnace valve to a second opening lower than the first opening to reduce the amount of air supplied to the dry distillation furnace, thereby lowering the temperature of the combustion furnace to the second predetermined temperature lower than the first predetermined temperature, and the hydrogen chloride concentration can be lowered accordingly. This allows the concentration detected by the hydrogen chloride concentration detection means to be equal to or lower than the first predetermined concentration.

[5] The dry distillation furnace, the dry distillation oxygen supply passage, and the dry distillation furnace valve are each provided in plurality,
When the concentration detected by the hydrogen chloride concentration detection means does not become lower than the first predetermined concentration even when the temperature of the combustion furnace is lowered to the second predetermined temperature, it is preferable that the control means lowers the aperture of the dry distillation furnace valve corresponding to a first dry distillation furnace among the plurality of dry distillation furnaces that introduces combustible gas into the combustion furnace to a third aperture lower than the second aperture, and opens the aperture of the dry distillation furnace valve corresponding to a second dry distillation furnace among the plurality of dry distillation furnaces that does not introduce combustible gas into the combustion furnace, thereby introducing combustible gas from the second dry distillation furnace into the combustion furnace.

According to the above configuration, when the concentration detected by the hydrogen chloride concentration detection means does not become equal to or lower than the first predetermined concentration even when the temperature of the first dry distillation furnace into which the combustible gas is introduced is lowered to the second predetermined temperature, but exceeds a third predetermined concentration higher than the second predetermined concentration, the control means lowers the opening degree of the dry distillation furnace valve corresponding to the first dry distillation furnace to the third opening degree lower than the second opening degree, and opens the opening degree of the dry distillation furnace valve corresponding to the second dry distillation furnace into which no combustible gas is introduced to the combustion furnace to introduce combustible gas from the second dry distillation furnace to the combustion furnace. This reduces the amount of combustible gas with a high hydrogen chloride concentration supplied from the first dry distillation furnace to the combustion furnace, and allows combustible gas with a low hydrogen chloride concentration to be supplied from the second dry distillation furnace to the combustion furnace. This allows the concentration detected by the hydrogen chloride concentration detection means to be equal to or lower than the first predetermined concentration.

FIG. 1 is a system configuration diagram showing the configuration of a dry distillation gasification incineration treatment apparatus of the present invention. Graph showing changes over time in incineration temperature, control valve opening of the first dry distillation furnace, hydrogen chloride concentration, neutralization capacity of the bag filter, amount of combustible gas, and control valve opening of the first dry distillation furnace.

The following describes in more detail the embodiments of the present invention with reference to the attached drawings.

As shown in FIG. 1, the dry distillation gasification incineration treatment device 1 of this embodiment includes two dry distillation furnaces 2a and 2b that store waste A such as waste tires and dry distillate, gasify, and incinerate it, and a combustion furnace 4 that is connected to the dry distillation furnaces 2a and 2b via gas passages 3a and 3b.

The upper surface of the dry distillation furnaces 2a, 2b are provided with inlets 6a, 6b each having an openable/closable input door 5a, 5b, through which waste A can be input into the dry distillation furnaces 2a, 2b. When the input doors 5a, 5b of the dry distillation furnaces 2a, 2b are closed, the interior of the dry distillation furnaces 2a, 2b is essentially isolated from the outside. The dry distillation furnaces 2a, 2b may be provided with a weighing device (not shown) that weighs a predetermined amount of waste A and inputs it into the dry distillation furnaces 2a, 2b through the inlets 6a, 6b.

A water jacket (not shown) is formed around the outer periphery of the dry distillation furnaces 2a and 2b as a cooling structure, isolated from the interior of the dry distillation furnaces 2a and 2b. The water jacket 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.

The lower part of the dry distillation furnace 2a, 2b is a bottom door 7a, 7b that can be moved downward, and when the bottom door 7a, 7b is closed, the inside of the dry distillation furnace 2a, 2b is essentially isolated from the outside. The lower part of the bottom door 7a, 7b is formed with an empty chamber 8a, 8b that is isolated from the inside of the dry distillation furnace 2a, 2b, and the empty chamber 8a, 8b is connected to the inside of the dry distillation furnace 2a, 2b via a plurality of air supply nozzles 9a, 9b provided on the bottom door 7a, 7b.

Dry distillation oxygen supply lines 10a, 10b are connected to the lower empty chambers 8a, 8b of the dry distillation furnaces 2a, 2b, respectively, and the dry distillation oxygen supply lines 10a, 10b are connected to an oxygen supply source 12 constituted by a forced draft fan or the like via an oxygen supply line 11. The dry distillation oxygen supply lines 10a, 10b are provided with control valves 13a, 13b (dry distillation furnace valves), respectively, and the opening degree of the control valves 13a, 13b is controlled by valve drivers 14a, 14b. In this case, the valve drivers 14a, 14b are controlled by a control device 15 (control means) constituted by an electronic circuit including a CPU, etc.

Furthermore, ignition devices 16a, 16b for igniting the waste A stored in the dry distillation furnaces 2a, 2b are attached to the bottom of the dry distillation furnaces 2a, 2b, respectively. The ignition devices 16a, 16b are composed of ignition burners or the like, and supply a combustion flame to the waste A by burning fuel supplied from fuel supply devices 17a, 17b via fuel supply paths 18a, 18b. Fuel such as diesel fuel is stored in the fuel supply devices 17a, 17b.

The combustion furnace 4 is composed of a burner section 19 that mixes the combustible gas produced by the dry distillation of waste A with the oxygen (air) necessary for its complete combustion, and a combustion section 20 that burns the combustible gas mixed with oxygen (air), and the combustion section 20 is connected to the burner section 19 on the downstream side of the burner section 19. Gas passages 3a and 3b are connected to the upstream side of the burner section 19 via dampers 21a and 21b, respectively, and the combustible gas produced by the dry distillation of waste A in the dry distillation furnaces 2a and 2b is introduced into the burner section 19 via the gas passages 3a and 3b.

A chamber (not shown) isolated from the interior of the burner section 19 is formed on the outer periphery of the burner section 19, and the chamber is connected to the interior of the burner section 19 via a number of nozzle holes (not shown) drilled in the inner periphery of the burner section 19. A combustion oxygen supply path 22 branching off from the oxygen supply path 11 is connected to the chamber. The combustion oxygen supply path 22 is arranged to pass through the combustion section 20 on the way, and oxygen (air) preheated in the combustion section 20 is supplied to the chamber.

A control valve 23 is provided in the combustion oxygen supply passage 22, and the opening degree of the control valve 23 is controlled by a valve driver 24. In this case, the valve driver 24 is controlled by the control device 15.

A combustion device 25 is attached upstream of the burner section 19. The combustion device 25 is composed of an ignition burner or the like, and ignites the combustible gas introduced into the burner section 19 or heats the combustion furnace 4 by burning fuel supplied from a fuel supply device 26 via a fuel supply passage 27. The fuel supply device 26 stores fuel such as diesel.

A boiler 28 is attached downstream of the combustion section 20 and is heated by the exhaust gas (waste heat) from combustion in the combustion furnace 4 via the boiler upstream duct 29a.

The boiler 28 is supplied with water by a water supply device (not shown), and steam heated using the heat from the combustion of the waste A is sent to a well-known turbine 30, which is rotated by the steam. The force of the rotation of the turbine 30 generates electricity in a well-known generator 31.

A boiler downstream duct 29b is provided at the outlet side of the boiler 28 to discharge the combustion exhaust gas cooled by the boiler 28.

The downstream end of the boiler downstream duct 29b is connected to the upper end of the quench tower 34. The quench tower 34 is equipped with a spray 35 that sprays water on the combustion exhaust gas introduced from the boiler downstream duct 29b to cool it, and the spray 35 is connected to a water supply device (not shown) that supplies cooling water and an air compressor (not shown).

The combustion exhaust cooled in the quench tower 34 is taken out through a duct 29e connected to the bottom of the quench tower 34 via an on-off valve 36.

Duct 29e is connected to one end of a bag filter 37 (neutralizer), and the combustion exhaust gas introduced from duct 29e into the bag filter 37 is mixed with hydrated lime and activated carbon supplied from a chemical silo 38, neutralizing, desulfurizing, and deodorizing the hydrogen chloride gas in the combustion exhaust gas.

The bag filter 37 has a filter section and a collection section that collects ash and other materials separated from the combustion exhaust by the filter section, and an air compressor (not shown) for cleaning the filter section is connected to the filter section. The other end of the bag filter 37 is connected to a duct 29f, which is connected to a chimney 40 via an induction fan 39 that draws in the combustion exhaust from the combustion furnace 4. As a result, the combustion exhaust circulating through the duct 29f is released into the atmosphere from the chimney 40.

The chimney 40 is provided with a hydrogen chloride concentration sensor 45 that detects the hydrogen chloride concentration inside the chimney 40, and the hydrogen chloride concentration sensor 45 transmits the detected concentration to the control device 15.

The control device 15 controls the operation of the chemical silo 38 according to the concentration detected by the hydrogen chloride concentration sensor 45, and adjusts the amount of slaked lime and activated carbon supplied from the chemical silo 38. When the concentration detected by the hydrogen chloride concentration sensor 45 becomes high, the control device 15 increases the amount of slaked lime and activated carbon supplied from the chemical silo 38, and when the concentration detected by the hydrogen chloride concentration sensor 45 becomes low, the control device 15 decreases the amount of slaked lime and activated carbon supplied from the chemical silo 38.

In this embodiment, the control device 15 adjusts the amount of hydrated lime and activated carbon supplied from the chemical silo 38 so that the concentration detected by the hydrogen chloride concentration sensor 45 is equal to or less than a first predetermined concentration (e.g., 120 ppm (parts per million)).

The neutralization capacity (%) of hydrogen chloride gas by the bag filter 37 is determined by the amount of slaked lime and activated carbon supplied.

When the supply amount of slaked lime and activated carbon reaches a preset supply amount, the control device 15 determines that the neutralization capacity of the bag filter 37 for hydrogen chloride gas has reached 100%. The control device 15 also detects the ratio of the supply amount of slaked lime and activated carbon to the preset supply amount as the neutralization capacity (%).

Next, referring to FIG. 1, the process flow for performing the dry distillation, gasification and incineration process of waste using the dry distillation, gasification and incineration process apparatus 1 will be described.

When waste A is incinerated in the dry distillation gasification incineration treatment device 1, first, the input door 5a of the dry distillation furnace 2a is opened with the bottom door 7a closed, and waste A such as waste tires is input into the dry distillation furnace 2a through the input port 6a. If the dry distillation furnace 2a is equipped with the weighing device, a predetermined amount of waste A is weighed by the weighing device and input into the dry distillation furnace 2a through the input port 6a.

Next, the control device 15 detects that the waste A has been completely fed into the dry distillation furnace 2a and that the waste A is being stored in the dry distillation furnace 2a. The completion of the feeding of the waste A into the dry distillation furnace 2a can be detected, for example, by providing limit switches on the feeding door 5a and the bottom door 7a that are turned ON when the doors are closed, and detecting that the limit switches are ON. In addition, if the dry distillation furnace 2a is equipped with the weighing device, a feeding completed button may be provided on the weighing device, and the detection may be performed by detecting the operation of the feeding completed button. Furthermore, the detection may be performed by detecting that both limit switches are ON and that the feeding completed button is operated.

Then, the loading door 5a is closed to seal the inside of the dry distillation furnace 2a, and the combustion device 25 of the combustion furnace 4 is operated prior to ignition of the waste A, and preheating of the combustion furnace 4 is started by burning the fuel supplied from the fuel supply device 26 via the fuel supply path 27.

Next, the temperature inside the combustion furnace 4, detected by a temperature sensor (not shown), gradually rises due to the combustion of the fuel, and when it reaches, for example, 760°C, the control device 15 drives the valve driver 14a to set the opening of the control valve 13a to a predetermined opening, for example, 25%, and the supply of oxygen (air) from the oxygen supply source 12 to the dry distillation furnace 2a via the oxygen supply path 11 and the dry distillation oxygen supply path 10a begins.

When the control device 15 detects that the waste A has been completely fed into the dry distillation furnace 2a, that the waste A is contained in the dry distillation furnace 2a, and that the damper 21a is open, the ignition device 16a of the dry distillation furnace 2a is activated after a predetermined time, for example, 5 minutes. As a result, the fuel supplied from the fuel supply device 17a via the fuel supply path 18a is combusted by the ignition device 16a, igniting the waste A and starting partial combustion of the waste A.

Next, in the dry distillation furnace 2a, the valve driver 14a is controlled by the control device 15, and the opening of the control valve 13a is increased stepwise. As a result, the partial combustion of the waste A in the dry distillation furnace 2a gradually expands and stabilizes due to the oxygen (air) supplied from the oxygen supply source 12, and a fire bed is formed at the bottom of the waste A. When the fire bed is formed, the ignition device 16a is stopped, and the heat from the partial combustion of the waste A starts the dry distillation of the other parts of the waste A, and the generation of flammable gas begins. The generation of the flammable gas can be detected, for example, by disposing a temperature sensor (not shown) at a position facing the dry distillation furnace 2a in the gas passage 3a, and detecting an increase in temperature detected by the temperature sensor.

The internal space of the dry distillation furnace 2a is sucked through the combustion furnace 4 by the induction fan 39, so that the combustible gas is introduced into the burner section 19 through the gas passage 3a. In the burner section 19, the valve driver 24 is driven by the control device 15 to set the opening of the control valve 23 to a predetermined opening, and oxygen (air) is supplied from the oxygen supply source 12 through the oxygen supply passage 11 and the combustion oxygen supply passage 22. The combustible gas is then mixed with the oxygen (air) supplied through the combustion oxygen supply passage 22 and ignited by the combustion flame supplied from the combustion device 25, starting combustion in the combustion section 20.

Until the fire bed is formed, the temperature inside the combustion furnace 4 caused by the combustion of the combustible gas fluctuates slightly around 800°C for a while, but as the generation of the combustible gas becomes more active and spontaneous combustion begins, the temperature gradually rises and reaches a preset first temperature (hereinafter referred to as the first set temperature), for example 1000°C.

When the temperature in the combustion furnace 4 reaches the first set temperature due to the combustion of the combustible gas, the combustion device 25 is stopped, and the control device 15 starts feedback control of the generation of the combustible gas in the dry distillation furnace 2a. As a result, the opening of the control valve 13a is controlled so that the temperature in the combustion furnace 4 reaches the first set temperature due to the combustion of the combustible gas.

When the generation of the combustible gas is feedback-controlled by the control device 15 so that the temperature in the combustion furnace 4 becomes the first set temperature, and the temperature in the combustion furnace 4 falls to a second set temperature lower than the first set temperature, for example 945°C, the combustion device 25 is restarted and the combustion furnace 4 is heated by the heat of the combustion device 25. The combustion device 25 is stopped when the temperature in the combustion furnace 4 returns to the first set temperature.

The combustion exhaust gas generated by the combustion of the combustible gas in the combustion section 20 is cooled in the boiler 28 by heat exchange with the water circulating in the boiler 28, and is discharged into the boiler downstream duct 29b.

The steam heated in the boiler 28 using the exhaust gas from the combustion is sent to the turbine 30, which rotates the turbine 30, and the force of the rotation of the turbine 30 generates electricity in the generator 31.

The combustion exhaust gas from the boiler 28 is introduced into the quench tower 34 through the boiler downstream duct 29b, where it is cooled by cooling water sprayed from the spray 35, and discharged into the duct 29e. At this time, the on-off valve 36 downstream of the quench tower 34 is open.

Next, the exhaust gas discharged into duct 29e is mixed with hydrated lime and activated carbon supplied from chemical silo 38 for desulfurization and deodorization, and then introduced into bag filter 37 to remove ash, dust, etc., before being discharged into duct 29f and then released into the atmosphere from chimney 40.

In this embodiment, after the temperature inside the combustion furnace 4 due to the combustion of the combustible gas generated in the dry distillation furnace 2a reaches the first set temperature, the input door 5b is opened with the bottom door 7b of the dry distillation furnace 2b closed, and waste A such as waste tires is input into the dry distillation furnace 2b through the input port 6b. The input of waste A into the dry distillation furnace 2b can be performed in the same manner as the input into the dry distillation furnace 2a.

Next, after the control device 15 detects that the waste A has been completely fed into the dry distillation furnace 2b and that the waste A is being stored in the dry distillation furnace 2b, when the opening of the control valve 13a in the dry distillation furnace 2a reaches a predetermined opening, for example 50%, the damper 21b is opened, the valve driver 14b in the dry distillation furnace 2b is driven by the control device 15 to set the opening of the control valve 13b to a predetermined opening, for example 25%, and oxygen (air) is supplied from the oxygen supply source 12 to the dry distillation furnace 2b via the oxygen supply path 11 and the dry distillation oxygen supply path 10b.

Next, when the opening degree of the control valve 13a in the dry distillation furnace 2a reaches a first predetermined opening degree, for example 53%, the ignition device 16b in the dry distillation furnace 2b is activated. As a result, the waste A in the dry distillation furnace 2b is ignited by the combustion of the fuel supplied from the fuel supply device 17b via the fuel supply line 18b, and partial combustion of the waste A begins.

The control device 15 can detect the completion of feeding waste A into the dry distillation furnace 2b and that waste A is contained in the dry distillation furnace 2b in the same manner as in the case of the dry distillation furnace 2a.

Next, in the dry distillation furnace 2b, the valve driver 14b is controlled by the control device 15, and the opening of the control valve 13b is increased stepwise. As a result, the partial combustion of the waste A in the dry distillation furnace 2b gradually expands and stabilizes due to the oxygen (air) supplied from the oxygen supply source 12, and a fire bed is formed at the bottom of the waste A. When the fire bed is formed, the ignition device 16b is stopped.

Next, when the opening of the control valve 13a in the dry distillation furnace 2a reaches a second predetermined opening, for example 50%, which is smaller than the first predetermined opening (for example 53%), the control device 15 controls the valve driver 14b to reduce the opening of the control valve 13b to, for example, 15%, and oxygen (air) necessary and sufficient to maintain the fire bed is supplied from the oxygen supply source 12 to the dry distillation furnace 2b via the oxygen supply path 11 and the dry distillation oxygen supply path 10b.

As a result, the dry distillation furnace 2b is in a state where the fire bed is maintained but the dry distillation of the waste A contained in the furnace has not started, in other words, it is in a standby state where the dry distillation of the waste A can be started immediately if necessary. While the dry distillation furnace 2b is in the standby state, the opening of the control valve 13b is maintained at an opening degree where the dry distillation furnace 2b is supplied with the oxygen (air) necessary and sufficient to maintain the fire bed.

Next, when the opening degree of the control valve 13a in the dry distillation furnace 2a reaches a third predetermined opening degree, for example 60%, which is larger than the second predetermined opening degree (for example 50%), the valve driver 14b in the dry distillation furnace 2b is controlled by the control device 15 to increase the opening degree of the control valve 13b. As a result, the standby state is released, the dry distillation of the waste A contained in the dry distillation furnace 2b is started, and the flammable gas generated in the dry distillation furnace 2b is introduced into the burner section 19 of the combustion furnace 4 through the gas passage 3b. The generation of the flammable gas can be detected, for example, as in the case of the dry distillation furnace 2a, by a temperature sensor (not shown) disposed at a position facing the dry distillation furnace 2b in the gas passage 3b, and the temperature detected by the temperature sensor is increased.

Next, when the combustible gas generated in the second dry distillation furnace 2b is introduced into the combustion furnace 4, the control device 15 controls the aperture of the control valve 13a so that the temperature inside the combustion furnace 4 caused by the sum of the combustion of the combustible gas generated in the first dry distillation furnace 2a and the combustion of the combustible gas generated in the second dry distillation furnace 2b becomes the first set temperature, as described above. As a result, the aperture of the control valve 13a exceeds the third predetermined aperture (e.g., 60%) and reaches a maximum aperture, e.g., 80%, and then tends to decrease.

Next, the control device 15 fixes the opening of the control valve 13a to a predetermined opening via the valve driver 14a, while controlling the opening of the control valve 13b so that the temperature inside the combustion furnace 4 due to the combustion of the combustible gas generated in the dry distillation furnace 2b becomes the first set temperature, thereby feedback-controlling the generation of the combustible gas in the dry distillation furnace 2b. During this time, the generation of the combustible gas in the dry distillation furnace 2a completely ceases, and the combustible gas burned in the combustion furnace 4 switches from the combustible gas generated in the dry distillation furnace 2a to the combustible gas generated in the dry distillation furnace 2b.

As a result, in this embodiment, the flammable gas burned in the combustion furnace 4 can be smoothly switched from the flammable gas generated in the dry distillation furnace 2a to the flammable gas generated in the dry distillation furnace 2b.

The method for switching the combustible gas burned in the combustion furnace 4 from the combustible gas generated in the dry distillation furnace 2a to the combustible gas generated in the dry distillation furnace 2b is described in detail in WO2017/131158, and is performed in this manner. In addition, three or more dry distillation furnaces may be provided.

[Hydrogen chloride concentration control]
Next, control of the hydrogen chloride concentration in the combustion exhaust gas discharged into the atmosphere from the chimney 40 will be described.

As shown in FIG. 2, when the control device 15 starts the dry distillation of the dry distillation furnace 2a as the first dry distillation furnace (time t0), as described above, it sets the opening degree of the control valve 13a of the dry distillation furnace 2a to 25%. This starts the supply of oxygen (air) from the oxygen supply source 12 to the dry distillation furnace 2a via the oxygen supply path 11 and the dry distillation oxygen supply path 10a. Then, when the ignition device 16a of the dry distillation furnace 2a is activated, partial combustion of the waste A starts.

Next, in the dry distillation furnace 2a, the valve driver 14a is controlled by the control device 15, and the opening of the control valve 13a is increased stepwise. As a result, the partial combustion of the waste A in the dry distillation furnace 2a gradually expands and stabilizes due to the oxygen (air) supplied from the oxygen supply source 12, and a fire bed is formed at the bottom of the waste A. When the fire bed is formed, the ignition device 16a is stopped, and the heat from the partial combustion of the waste A starts the dry distillation of the other parts of the waste A, and the generation of flammable gas begins.

The combustible gas is introduced into the burner section 19 through the gas passage 3a. The combustible gas is mixed with oxygen (air) supplied through the combustion oxygen supply passage 22, and is ignited by the combustion flame supplied from the combustion device 25, starting combustion in the combustion section 20. Then, over time, the temperature inside the combustion furnace 4 rises, reaching 1000°C at time t1.

The hydrogen chloride concentration sensor 45 installed in the chimney 40 detects the hydrogen chloride concentration inside the chimney 40 and transmits the detected concentration to the control device 15.

The control device 15 adjusts the amount of hydrated lime and activated carbon supplied from the chemical silo 38 so that the concentration detected by the hydrogen chloride concentration sensor 45 is equal to or less than a first predetermined concentration (120 ppm).

From time t0 to time t1, as the temperature inside the combustion furnace 4 rises, the concentration detected by the hydrogen chloride concentration sensor 45, the neutralization capacity of the hydrogen chloride gas by the bag filter 37 (supply amount of slaked lime and activated carbon), and the amount of gas increase. Note that the values in Figure 2 are merely illustrative examples and can be changed as appropriate.

When the hydrogen chloride gas neutralization capacity of the bag filter 37 reaches 100% (the supply amount of slaked lime and activated carbon reaches a predetermined supply amount) (time t2), the concentration detected by the hydrogen chloride concentration sensor 45 increases from time t2 onwards.

When the neutralization capacity of the bag filter 37 for hydrogen chloride gas is 100% and the concentration detected by the hydrogen chloride concentration sensor 45 exceeds the first predetermined concentration (120 ppm) (time t3), the control device 15 reduces the opening of the control valve 13a of the dry distillation furnace 2a. This reduces the amount of air supplied to the dry distillation furnace 2a, reduces the amount of combustible gas supplied from the dry distillation furnace 2a to the combustion furnace 4 (reduces the amount of combustible gas combusted in the combustion furnace 4), and lowers the temperature of the combustion furnace 4.

In this embodiment, the control device 15 reduces the opening of the control valve 13a of the dry distillation furnace 2a so that the temperature of the combustion furnace 4 decreases from 1000°C to a first predetermined temperature (e.g., 900°C). As a result, after time t3, the concentration detected by the hydrogen chloride concentration sensor 45 and the amount of gas decrease, and the concentration detected by the hydrogen chloride concentration sensor 45 can be reduced to below the first predetermined concentration (120 ppm).

In addition, as described above, when the opening of the control valve 13a of the dry distillation furnace 2a is reduced, the amount of combustible gas supplied from the dry distillation furnace 2a decreases, and the combustion temperature of the combustion furnace 4 drops. In this case, if the amount of air supplied to the combustion furnace 4 is not changed, there may be an excess of combustion air, and self-combustion may not continue and combustion may stop.

In this embodiment, even if the combustion temperature of the combustion furnace 4 drops, in order to achieve complete combustion and self-combustion in the combustion furnace 4 within the appropriate air ratio range, the control device 15 controls the opening of the control valve 23 via the valve driver 24 to reduce the amount of air supplied to the combustion furnace 4. As a result, even if the combustion temperature of the combustion furnace 4 drops, the combustion furnace 4 can achieve complete combustion and self-combustion in the appropriate air ratio range. Note that if the combustion temperature of the combustion furnace 4 rises, the control device 15 controls the opening of the control valve 23 via the valve driver 24 to increase the amount of air supplied to the combustion furnace 4. This control of the opening of the control valve 23 is performed when the combustion temperature of the combustion furnace 4 fluctuates.

In addition, after time t3, as the concentration detected by the hydrogen chloride concentration sensor 45 decreases, the ability of the bag filter 37 to neutralize the hydrogen chloride gas also decreases.

When the concentration detected by the hydrogen chloride concentration sensor 45 falls to a second predetermined concentration (e.g., 80 ppm) (time t4), the control device 15 increases the aperture of the control valve 13a of the dry distillation furnace 2a. This increases the amount of air supplied to the dry distillation furnace 2a, increases the amount of combustible gas combusted in the combustion furnace 4, and increases the temperature of the combustion furnace 4.

In this embodiment, the control device 15 increases the opening of the control valve 13a of the dry distillation furnace 2a so that the temperature of the combustion furnace 4 rises from the first predetermined temperature (900°C) to 1000°C. As a result, after time t3, the concentration detected by the hydrogen chloride concentration sensor 45, the neutralization ability of the hydrogen chloride gas by the bag filter 37, and the amount of gas increase.

Then, when the neutralization capacity of the hydrogen chloride gas by the bag filter 37 is 100% and the concentration detected by the hydrogen chloride concentration sensor 45 exceeds the first predetermined concentration (120 ppm) (time t5), the control device 15 reduces the aperture of the control valve 13a of the dry distillation furnace 2a. At this time t5, similar to the time t3 described above, the control device 15 reduces the aperture of the control valve 13a of the dry distillation furnace 2a so that the temperature of the combustion furnace 4 drops from 1000°C to the first predetermined temperature (900°C). As a result, the amount of gas decreases after time t5.

Even if the temperature of the combustion furnace 4 is lowered from 1000°C to the first predetermined temperature (900°C), the concentration detected by the hydrogen chloride concentration sensor 45 does not decrease but increases, and when it exceeds the second predetermined concentration (e.g., 140 ppm) (time t6), the control device 15 further reduces the opening of the control valve 13a of the dry distillation furnace 2a.

At this time t6, the control device 15 reduces the aperture of the control valve 13a of the dry distillation furnace 2a so that the temperature of the combustion furnace 4 drops from the first predetermined temperature (900°C) to a second predetermined temperature (e.g., 850°C). As a result, the amount of gas decreases after time t6.

If the concentration detected by the hydrogen chloride concentration sensor 45 drops below the first predetermined concentration (120 ppm) to a second predetermined concentration (e.g., 80 ppm) due to the control at time t6 (reducing the temperature of the combustion furnace 4 from 900°C to 850°C), the same control as at time t4 is performed.

On the other hand, when the concentration detected by the hydrogen chloride concentration sensor 45 does not decrease but increases even when the temperature of the combustion furnace 4 is lowered from the first predetermined temperature (900°C) to the second predetermined temperature (e.g., 850°C) and exceeds the third predetermined concentration (e.g., 160 ppm) (time t7), the control device 15 reduces the opening of the control valve 13a of the dry distillation furnace 2a to 15%. This reduces the amount of air supplied to the dry distillation furnace 2a, reduces the amount of combustible gas burned in the combustion furnace 4, reduces the introduction of combustible gas from the dry distillation furnace 2a to the combustion furnace 4, and makes it possible to make the concentration detected by the hydrogen chloride concentration sensor 45 equal to or lower than the first predetermined concentration (120 ppm).

Furthermore, at time t7, the control device 15 activates the ignition device 16b (ignition burner) of the second dry distillation furnace 2b. As a result, the waste A in the dry distillation furnace 2b is ignited by the combustion of the fuel supplied from the fuel supply device 17b via the fuel supply line 18b, and partial combustion of the waste A is initiated.

This starts the dry distillation of the waste A contained in the dry distillation furnace 2b, and the combustible gas generated in the dry distillation furnace 2b is introduced into the burner section 19 of the combustion furnace 4 via the gas passage 3b.

When the combustible gas generated in the dry distillation furnace 2b is introduced into the combustion furnace 4, the control device 15 fixes the opening of the control valve 13a to a predetermined opening via the valve driver 14a, while controlling the opening of the control valve 13b so that the temperature inside the combustion furnace 4 due to the combustion of the combustible gas generated in the dry distillation furnace 2b becomes the first set temperature (1000°C), thereby feedback controlling the generation of the combustible gas in the dry distillation furnace 2b.

By using this type of control, the temperature inside the combustion furnace 4 can be kept above 800°C, which is the safe combustion temperature.

In this embodiment, by reducing the introduction of combustible gas from the dry distillation furnace 2a to the combustion furnace 4 and starting the introduction of combustible gas from the dry distillation furnace 2b to the combustion furnace 4, the concentration detected by the hydrogen chloride concentration sensor 45 can be reduced to a first predetermined concentration (120 ppm) or less while maintaining the temperature inside the combustion furnace 4 at or above the combustion safety temperature (800°C). Accordingly, the neutralization ability of the hydrogen chloride gas by the bag filter 37 also decreases.

Then, at time t8, the temperature inside the combustion furnace 4 rises to the first set temperature (1000°C), and the control device 15 controls the temperature inside the combustion furnace 4 to be kept at the first set temperature (1000°C). Even at time t8, the hydrogen chloride concentration is about 100 ppm, which is below the first predetermined concentration (120 ppm), and the neutralization capacity of the hydrogen chloride gas by the bag filter 37 is also about 70%, which is less than 100%.

After that, the above control is performed by reversing the operation of the dry distillation furnace 2a and the dry distillation furnace 2b. By repeating this process, the hydrogen chloride concentration can be kept below the specified value (first predetermined concentration (120 ppm)) and the furnaces can be operated continuously.

The present invention has been described above in terms of its preferred embodiments, but as will be readily understood by those skilled in the art, the present invention is not limited to such embodiments and can be modified as appropriate without departing from the spirit of the present invention.

For example, in the above embodiment, the present invention is implemented in a dry distillation gasification incineration processing apparatus 1 equipped with two dry distillation furnaces 2a and 2b, but it may also be implemented in a dry distillation gasification incineration processing apparatus 1 equipped with one or three or more dry distillation furnaces.

In the above embodiment, various controls are performed at times t3, t4, t5, t6, and t7, but it is sufficient to perform control at least at time t3.

In the above embodiment, at time t3, the control device 15 reduces the aperture of the control valve 13a of the dry distillation furnace 2a so that the temperature of the combustion furnace 4 drops from 1000°C to the first predetermined temperature (900°C), thereby reducing the neutralization capacity of the hydrogen chloride gas by the bag filter 37. However, the aperture of the control valve 13a of the dry distillation furnace 2a may be reduced so that the temperature of the combustion furnace 4 is increased to a temperature higher than the above 900°C (e.g., 930°C) by maintaining the neutralization capacity of the hydrogen chloride gas by the bag filter 37 at 100%. In either case, the concentration detected by the hydrogen chloride concentration sensor 45 is controlled to be equal to or lower than the specified value.

In the above embodiment, a first temperature reduction control is performed to reduce the temperature of the combustion furnace 4 from 1000°C to a first predetermined temperature (900°C), and a second temperature reduction control is performed to reduce the temperature of the combustion furnace 4 from the first predetermined temperature (900°C) to a second predetermined temperature (e.g., 850°C). Even when the second control is performed, if the concentration detected by the hydrogen chloride concentration sensor 45 does not decrease but increases and exceeds the third predetermined concentration (160 ppm), an opening control is performed to reduce the opening of the control valve 13a of the dry distillation furnace 2a to 15%, but the number of times the temperature reduction control is performed can be changed as appropriate. For example, the temperature reduction control can be performed three or more times before the opening control, and the threshold value (temperature) in that case can also be changed as appropriate.

In the above embodiment, a bag filter 37 that mixes slaked lime and activated carbon for neutralization is provided as the neutralization means, but the neutralization device is not limited to this, and may be, for example, one that sprays slaked lime slurry or caustic soda into the quenching tower 34, or one that doubles as the bag filter 37. Furthermore, it is not necessary to provide a neutralization means.

In addition, in rotary kilns and stoker-type dry distillation and gasification incineration treatment equipment that continuously feeds in waste, the feed material is thoroughly mixed to prevent the concentration of waste that generates hydrogen chloride. If waste does enter the furnace, water can be sprayed into the furnace to suppress combustion and to extend the residence time in the furnace, thereby suppressing the generation of hydrogen chloride gas.

1...Dry distillation gasification incineration treatment device, 2a, 2b...Dry distillation furnace, 4...Combustion furnace, 10a, 10b...Oxygen supply line, 12...Oxygen supply source, 13a, 13b...Control valve (dry distillation furnace valve), 15...Control device, 37...Bag filter (neutralization means), 45...Hydrogen chloride concentration sensor (hydrogen chloride concentration detection means), A...Waste

Claims (5)

A dry distillation gasification incineration treatment apparatus comprising: a dry distillation furnace for storing waste and burning a portion of the waste while dry distilling the remainder of the waste using the combustion heat to generate a combustible gas; a combustion furnace for burning the combustible gas supplied from the dry distillation furnace; a dry distillation oxygen supply means for supplying oxygen required for burning a portion of the waste in the dry distillation furnace to the dry distillation furnace via a dry distillation oxygen supply line; a combustion oxygen supply means for supplying oxygen required for burning the combustible gas introduced into the combustion furnace to the combustion furnace; and a dry distillation furnace valve provided in the dry distillation oxygen supply line for adjusting the oxygen supplied to the dry distillation furnace,
a hydrogen chloride concentration detection means for detecting the hydrogen chloride concentration of the gas discharged from the combustion furnace;
a control means for controlling a temperature of the combustion furnace by driving the dry distillation furnace valve to adjust the amount of air supplied to the dry distillation furnace based on the concentration detected by the hydrogen chloride concentration detection means;
A dry distillation gasification incineration treatment device comprising: The dry distillation gasification incineration treatment apparatus according to claim 1,
a neutralizing means for neutralizing hydrogen chloride in the gas discharged from the combustion furnace,
The hydrogen chloride concentration detection means detects the hydrogen chloride concentration of the gas after neutralization by the neutralization means,
The control means, when the neutralization capacity of the neutralization means reaches its maximum, reduces the temperature of the combustion furnace by reducing the opening of the dry distillation furnace valve and reducing the amount of air supplied to the dry distillation furnace based on the concentration detected by the hydrogen chloride concentration detection means. In the dry distillation gasification and incineration treatment device according to claim 1 or 2,
The control means, when the concentration detected by the hydrogen chloride concentration detection means exceeds a first predetermined concentration, reduces the opening of the dry distillation furnace valve to a first opening to reduce the amount of air supplied to the dry distillation furnace, thereby reducing the temperature of the combustion furnace to a first predetermined temperature. In the dry distillation gasification and incineration treatment device according to claim 3,
The control means, when the concentration detected by the hydrogen chloride concentration detection means does not become equal to or lower than the first predetermined temperature even when the temperature of the combustion furnace is lowered to the first predetermined temperature, reduces the opening degree of the dry distillation furnace valve to a second opening degree lower than the first opening degree to reduce the amount of air supplied to the dry distillation furnace, thereby lowering the temperature of the combustion furnace to a second predetermined temperature lower than the first predetermined temperature. The dry distillation gasification incineration treatment apparatus according to claim 4,
The dry distillation furnace, the dry distillation oxygen supply passage, and the dry distillation furnace valve are each provided in plurality,
The control means, when the temperature of the combustion furnace is lowered to the second predetermined temperature and the detected concentration of the hydrogen chloride concentration detection means does not become equal to or lower than the first predetermined concentration, lowers the opening degree of the dry distillation furnace valve corresponding to a first dry distillation furnace among the multiple dry distillation furnaces that introduces combustible gas into the combustion furnace to a third opening degree lower than the second opening degree, and opens the opening degree of the dry distillation furnace valve corresponding to a second dry distillation furnace among the multiple dry distillation furnaces that does not introduce combustible gas into the combustion furnace, thereby introducing combustible gas from the second dry distillation furnace into the combustion furnace.

Images