JP4878943B2 - Method and apparatus for controlling supply of combustion air to a rotary kiln furnace - Google Patents

Description

  The present invention relates to a supply control method and a supply control device for combustion air to a rotary kiln furnace in a waste combustion facility.

  2. Description of the Related Art Conventionally, a rotary kiln furnace for burning waste (hereinafter referred to as a kiln furnace) and a stoker furnace having a boiler section for burning the combustion residue from the kiln furnace and unburned components in exhaust gas and recovering waste heat (For example, see Patent Document 1). An exhaust gas treatment facility is provided after the stoker furnace in order to render the combustion exhaust gas harmless.

  By the way, the waste feed rate in this combustion facility and the combustion control in the kiln furnace and the stoker furnace, that is, the supply control of the combustion air into each furnace, of course, are made to the input amount of waste (which is the processing amount). Is performed based on the amount of evaporation in a boiler section provided in the stoker furnace, and further, in order to prevent generation of harmful substances such as dioxin in the stoker furnace, in other words, complete combustion is performed.

In other words, once the amount of waste input to the kiln furnace is determined, the waste supply rate to the kiln furnace, the rotation speed of the kiln furnace, the amount of evaporation in the boiler section of the stoker furnace, etc. are set based on this input amount. When the evaporation amount in the boiler section is set, the supply amount of the combustion air supplied to the kiln furnace and the stoker furnace is controlled based on the set evaporation amount (for example, Patent Document 2).
JP 2004-361030 A JP-A-62-255717

  By the way, when performing combustion control with the above-described combustion facility, if it is attempted to suppress the generation of harmful substances such as dioxins in a stoker furnace, the combustion residue discharged from the kiln furnace and the unburned content in the exhaust gas are inevitably required. Therefore, it is necessary to satisfactorily perform combustion control in the kiln furnace, that is, supply control of combustion air. For this purpose, it is necessary to grasp the combustion state in the kiln furnace.

  However, when trying to grasp the combustion state in the kiln furnace, it can be grasped to some extent using a thermometer on the front side, but especially on the rear side, especially near the exit of the kiln furnace close to the stoker furnace However, since the combustion is intense, it is difficult to grasp the combustion state using a thermometer, and therefore there is a possibility that the combustion state in the kiln furnace cannot be properly maintained. Although it is conceivable to sufficiently supply combustion air to the kiln furnace to reduce the combustion residue sufficiently, the outlet temperature on the kiln furnace side becomes too high, and the clinker adheres to the inner wall surface. Occurs.

  Accordingly, the present invention supplies appropriate combustion air to the kiln furnace by grasping the combustion state in the kiln furnace, particularly the combustion state in the vicinity of the outlet in the waste combustion facility equipped with the rotary kiln furnace. An object of the present invention is to provide a method and a supply control device for supplying combustion air to a rotary kiln that can be used.

In order to solve the above problems, a method for controlling the supply of combustion air to a rotary kiln according to claim 1 of the present invention is a rotary kiln that is a primary combustion furnace for burning waste, and is discharged from the rotary kiln. A waste having a secondary combustion furnace having a boiler section for further burning waste residue and unburned exhaust gas and recovering waste heat, and an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace A method for controlling the supply of combustion air to the rotary kiln in the combustion facility,
For the amount of air supplied to the rotary kiln furnace set in advance based on the amount of waste input,
Oxygen obtained by subtracting the residual oxygen amount discharged from the exhaust gas treatment facility from the oxygen amount supplied to the secondary combustion furnace and the exhaust gas treatment facility and dividing the difference value by the air amount supplied to the rotary kiln furnace This is a method of performing correction with oxygen so that the concentration falls within a preset setting range.

According to a second aspect of the present invention, there is provided a method for controlling the supply of combustion air to a rotary kiln furnace comprising: a rotary kiln furnace that is a primary combustion furnace for burning waste; To a rotary kiln furnace in a waste combustion facility having a secondary combustion furnace having a boiler section for further combusting the waste and recovering waste heat, and an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace A combustion air supply control method for
Based on the set evaporation amount in the boiler section obtained from the input amount of waste, the pre-stage air amount as the pre-set amount to be supplied to the pre-stage side of the rotary kiln furnace and the intermediate stage as the pre-set amount to be supplied to the intermediate stage side Find the air volume,
Pre-stage supply air quantity supplied to the pre-stage side by correcting the temperature so that the measured temperature measured on the pre-stage side of the rotary kiln is within a preset setting range with respect to the pre-stage air quantity. Seeking
The air supplied to the rotary kiln furnace by subtracting the residual oxygen amount discharged from the exhaust gas treatment facility from the oxygen amount supplied to the secondary combustion furnace and the exhaust gas treatment facility with respect to the intermediate stage air amount. This is a method for obtaining the intermediate stage supply air amount supplied to the intermediate stage by performing correction with oxygen so that the oxygen concentration obtained by dividing by the quantity is within a preset setting range.

  According to a third aspect of the present invention, there is provided a combustion air supply control method for a rotary kiln furnace according to claim 2, further comprising a boiler for the intermediate air amount corrected by the oxygen amount in the combustion air supply control method according to the second aspect. This is a method of performing correction based on the evaporation amount so that the measured evaporation amount in the unit becomes a preset evaporation amount set in advance.

According to a fourth aspect of the present invention, there is provided a control device for supplying combustion air to a rotary kiln furnace comprising: a rotary kiln furnace that is a primary combustion furnace for burning waste; and unburned combustion residue and exhaust gas discharged from the rotary kiln furnace. To a rotary kiln furnace in a waste combustion facility having a secondary combustion furnace having a boiler section for burning waste and recovering waste heat, and an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace A combustion air supply control device comprising:
The amount of air to be supplied to the front stage air amount setting unit and the intermediate stage side for setting the amount of air to be supplied to the front stage side of the rotary kiln furnace based on the set evaporation amount in the boiler section obtained from the input amount of waste An intermediate air amount setting section to be set;
Correction is made so that the measured temperature measured by the thermometer provided on the front stage side of the rotary kiln is within a preset setting range with respect to the front stage air quantity obtained by the preceding stage air quantity setting unit. A temperature correction unit to perform,
The oxygen concentration is obtained by dividing the difference obtained by subtracting the amount of residual oxygen discharged from the exhaust gas treatment facility from the amount of oxygen supplied to the secondary combustion furnace and the exhaust gas treatment facility by the amount of air supplied to the rotary kiln furnace. An oxygen calculation unit to be obtained;
The intermediate stage air amount determined by the intermediate stage air amount setting unit is corrected so that the oxygen amount at the kiln furnace outlet determined by the oxygen calculating unit is within a preset setting range. And an oxygen correction unit.

A combustion air supply control device for a rotary kiln according to claim 5 is the combustion air supply control device according to claim 4, wherein an evaporation for obtaining a deviation between a set evaporation amount in the boiler section and a measured evaporation amount is obtained. A quantity deviation calculator,
An evaporation amount correction unit that inputs the intermediate stage correction air amount corrected by the oxygen correction unit and further corrects the intermediate stage correction air amount so that the deviation obtained by the evaporation amount deviation calculation unit is eliminated. It is a thing.

Furthermore, the combustion air supply control device to the rotary kiln according to claim 6 is the combustion air supply control device according to claim 5,
Oxygen calculator
An air amount adding unit for adding the respective air amounts measured by flow meters provided in the secondary combustion furnace and the exhaust gas treatment facility to obtain a total supply air amount supplied behind the rotary kiln furnace;
A supply oxygen amount calculation unit that obtains an oxygen amount included in the total supply air amount by multiplying the total supply air amount obtained by the air amount addition unit by the oxygen concentration of the supplied air;
A kiln for subtracting the total supply air amount obtained by the supply air amount calculation unit from the total exhaust gas amount measured by a flow meter provided at the rear stage of the exhaust gas treatment facility to obtain the exhaust gas amount at the kiln furnace outlet A furnace outlet exhaust gas amount calculation unit;
A residual oxygen amount calculation unit for obtaining the residual oxygen amount in the total exhaust gas by multiplying the total exhaust gas amount by the oxygen concentration measured by an oxygen concentration meter provided on the rear stage side of the exhaust gas treatment facility;
A kiln furnace outlet oxygen amount calculation unit for subtracting the supply oxygen amount determined by the supply oxygen amount calculation unit from the residual oxygen amount determined by the residual oxygen amount calculation unit to obtain the kiln furnace outlet oxygen amount;
The kiln furnace outlet oxygen amount calculating unit is configured by an oxygen concentration calculating unit that calculates an oxygen concentration by dividing the kiln furnace outlet oxygen amount determined by the kiln furnace outlet exhaust gas amount calculating unit by the exhaust gas amount calculated by the kiln furnace outlet exhaust gas amount calculating unit. Is.

  According to the combustion air supply control method according to claim 1, when the amount of air supplied to the rotary kiln furnace set based on the input amount of waste is corrected, the residual exhausted from the waste combustion facility Since it was performed based on the oxygen concentration at the kiln furnace outlet determined from the oxygen amount and the supplied oxygen quantity, it was more appropriate than the conventional case where it was difficult to grasp the combustion state at the kiln furnace outlet. An oxygen amount, that is, combustion air can be supplied.

  Moreover, according to the structure of the combustion air supply control method and the supply control device according to claims 2 to 6, the upstream air to be supplied to the upstream side of the kiln furnace set based on the set evaporation amount in the boiler section. The quantity is corrected based on the properties of the waste, and the furnace temperature at the previous stage is corrected to be within the set temperature range, so the furnace temperature can be set to an appropriate value, For example, the temperature can be reduced to a temperature at which clinker is not generated, and therefore combustion on the upstream side of the kiln furnace can be performed satisfactorily.

  Furthermore, for the intermediate stage air amount to be supplied to the intermediate stage side of the kiln furnace set based on the set evaporation amount in the boiler section, in particular, correction is made based on the oxygen concentration at the kiln furnace outlet, and in the stoker furnace Since the correction is performed so that the amount of evaporation in the boiler section becomes the set amount of evaporation, combustion after the intermediate stage of the kiln furnace can be maintained well and the amount of evaporation in the boiler section is kept constant. can do.

[Embodiment]
Hereinafter, a combustion air supply control method and a supply control device in a rotary kiln furnace of a waste combustion facility according to an embodiment of the present invention will be described with reference to FIGS.

First, a schematic overall configuration of the waste combustion facility will be described.
As shown in FIG. 1, this waste combustion facility includes a rotary kiln furnace (hereinafter referred to as a kiln furnace) as a primary combustion furnace that burns waste supplied from a storage pit via a bucket provided in an overhead traveling crane, for example. 1), combustion residue (also referred to as incineration residue) and exhaust gas discharged from the kiln furnace 1 are introduced, the unburned matter contained in the combustion residue and the unburned content in the exhaust gas are burned, and the waste heat is recovered. Stoke-type secondary combustion furnace or stoker furnace 2 and the exhaust gas discharged from the stoker furnace 2 are made harmless (specifically, harmful components and dust in the exhaust gas are removed) and released to the atmosphere An exhaust gas treatment facility 3 and a control device 4 for controlling the combustion state in at least the kiln furnace 1 and the stoker furnace 2.

  The kiln furnace 1 is supported so as to be rotatable about a substantially horizontal axis (exactly, slightly inclined so that the discharge port is positioned lower than the supply port), A rotary drive device 13 such as an electric motor for rotating the furnace body 11 via the ring gear 12 and a pusher-type waste supply device disposed in a hood portion 14 provided on the supply port side of the furnace body 11. 15, a front air supply nozzle 16 provided in the hood portion 14 for supplying combustion air (which is also primary combustion air on the kiln side) to the front portion of the furnace body 11, and an intermediate portion of the furnace body 11. In order to supply combustion air (which is also secondary combustion air on the kiln side) from an air distribution pipe 17 arranged on the outer periphery to an intermediate portion of the furnace body 11, at predetermined intervals along the circumferential direction of the furnace body 11. Multiple intermediate stages arranged A gas supply nozzle 18, and a kiln-side air supply device 19. for supplying combustion air to the respective air supply nozzles 16, 18.

  The intermediate stage air supply nozzles 18 are arranged in two front and rear rows, and are configured by a front side intermediate stage air supply nozzle 18A and a rear side intermediate stage air supply nozzle 18B, and the jet directions of the supply nozzles 18A and 18B are kilns. The rotation direction is opposite to the rotation direction, and the nozzle is provided so as to face obliquely backward in the range of 15 to 60 degrees with respect to the vertical plane on which the nozzle is disposed. Of course, the tip of the intermediate stage air supply nozzle 18 has a length that protrudes sufficiently upward from the layered waste surface in the furnace body 11.

  As for the configuration of the air distribution pipe 17, the intermediate stage air supply nozzle 18 is provided in the furnace body 11 on the rotation side, and specifically, provided in the furnace body 11 to form a moving side air supply passage. For example, an inner annular groove portion 17a, and an outer annular lid portion 17b that is provided on the frame side that supports the furnace body 11 and forms a fixed-side air supply passage that can cover the moving-side air supply passage.

  The kiln-side air supply device 19 includes a blower 21, a main air pipe 22 for supplying air from the blower 21 to the front-stage air supply nozzle 16 and the intermediate-stage air supply nozzle 18, and each nozzle from the main air pipe 22. The first and second flowmeters 24 and 25 for measuring the supply amount of the combustion air are respectively connected to the branch air pipes 23 for leading to the respective air supply locations. Are provided, and first and second dampers (which are air amount regulators) 26 and 27 capable of controlling the respective air supply amounts are provided.

  In the following, the position of the front air supply nozzle 16 of the furnace body 11 (for example, the position immediately before the nozzle) is the first point (A), and the position of the front intermediate stage air supply nozzle 18A (for example, the position immediately before the nozzle). ) Is the second point (b), the position of the rear intermediate stage air supply nozzle 18B (for example, the position immediately before the nozzle) is the third point (c), and the outlet of the furnace body 11 (hereinafter referred to as the kiln furnace outlet). Is referred to as a fourth point (d), and the first to third thermometers that can measure the temperature of the waste in the furnace body 11 are provided at the first to third points (a) to (c). 28 to 30 are provided.

  The stoker furnace 2 includes a main combustion chamber 32 in which a grate 31 for further burning the unburned portion of the combustion residue discharged from the kiln furnace 1 and the unburned portion contained in the exhaust gas is disposed. A secondary combustion chamber 33 disposed above the combustion chamber 32; a boiler section 35 provided in a flue section 34 for guiding exhaust gas burned in the secondary combustion chamber 33 for heat recovery; and the grate A grate air supply device 36 and a secondary combustion chamber air supply device 37 for supplying combustion air to the lower combustion chamber 33 and to the secondary combustion chamber 33.

  The grate air supply device 36 includes a blower 38, an air supply pipe 40 for supplying air from the blower 38 to a wind box 39 below the grate 31, and a midway in the air supply pipe 40. The secondary combustion chamber air supply device 37 includes a blower 42 and air from the blower 42. The third damper (air amount regulator) 41 is configured to adjust the supply amount of air. An air supply pipe 43 for supplying to the next combustion chamber 33 and a fourth damper (air quantity regulator) 44 provided in the middle of the air supply pipe 43 and capable of adjusting the air supply quantity. . Further, in the middle of the air supply pipes 40 and 43, third and fourth flow meters 45 and 46 are provided.

  The boiler unit 35 includes an air-water separator 47 that guides boiler water supplied to water pipe wall portions provided in the secondary combustion chamber 33 and the flue portion 34 and separates saturated steam, and a flue portion 34. And the superheated pipe 48 that guides the saturated steam separated by the steam separator 47 and superheats it, and the superheated steam that is superheated by the superheated pipe 48 (for example, a gas turbine, a water heater, etc.) And a steam flow meter 50 for measuring the evaporation amount (steam amount) is provided in the middle of the steam extraction tube 49.

  Furthermore, the exhaust gas treatment facility 3 guides the exhaust gas discharged from the flue portion 34 of the stoker furnace 2 through the connection pipe 51 and cools it to a predetermined temperature. A dust collector (for example, a bag filter) 54 that guides the temperature-controlled exhaust gas through the connection pipe 53 and removes dust, and induces the exhaust gas from which dust has been removed by the dust collector 54 in the middle In order to render the gas harmless by being provided in front of the gas discharge cylinder 57 and a gas discharge cylinder 57 (which is a so-called chimney) that is guided through the exhaust gas outlet pipe 56 provided with the blower 55 and released to the atmosphere. A catalyst reaction cylinder (not shown) having the above catalyst, a water supply pipe 62 for supplying water to the spray nozzle 61 provided in the temperature control tower 52, an air supply pipe 63 for supplying spraying air, and spraying Air supply pipe to nozzle 61 4 and a blower 65 for supplying purging air through the, and a Metropolitan blower 67 for supplying middle air for drug infusion through the infusion tube 66 of the connecting tube 53. Of course, although not shown, the drug injection pipe 66 is provided with a drug injection port.

  Further, a fifth flow meter 71 is arranged in the middle of the exhaust gas outlet pipe 56, a sixth flow meter 72 is arranged in the middle of the air supply pipe 63, and further, on the discharge port side of the gas discharge cylinder 57, An oxygen concentration meter 73 for measuring the oxygen concentration in the exhaust gas is provided. Note that the amount of air supplied from the air supply pipe 64 that supplies the purge air and the amount of air supplied from the drug injection pipe 66 are fixed amounts, which are known amounts.

Next, a control system in the waste combustion facility, that is, the control device 4 will be described.
As shown in FIG. 2, the control device 4 is roughly divided into a waste input amount determination unit 81 that determines the input amount of waste, and a kiln based on the input amount from the waste input amount determination unit 81. A kiln furnace rotation speed setting unit 82 that sets the rotation speed of the furnace body 11 of the furnace 1 and a waste supply device 15 that supplies waste into the kiln furnace 1 based on the input amount from the waste input amount determination unit 81. A waste supply speed setting unit 83 for setting the supply speed of the kiln, a kiln furnace rotation speed control unit 84 for controlling the rotation drive device 13 based on the rotation speed set by the kiln furnace rotation speed setting unit 82, and the above Generated based on the waste supply rate control unit 85 that controls the waste supply device 15 based on the set supply rate set by the waste supply rate setting unit 83 and the input amount from the waste input amount determination unit 81. Set evaporation amount An evaporation amount setting unit 91, a kiln furnace side air supply control unit 92 that controls the amount of air supplied to the kiln furnace 1 based on the evaporation amount set by the evaporation amount setting unit 91, and the evaporation amount setting unit 91 A stoker-furnace-side air supply control unit 93 that sets the amount of air supplied to the stoker furnace 2 based on the set evaporation amount is provided.

  By the way, the gist of the present invention is that the exhaust gas properties discharged from the kiln furnace 1 to the stoker furnace 2 so that the exhaust gas discharged from the waste combustion facility (for example, the concentration of exhaust gas components, the amount of exhaust gas, etc.) becomes appropriate. The temperature in the kiln furnace 1 is also within a predetermined range (for example, the clinker generation temperature, specifically, within a predetermined range of 1100 ° C. or lower) while considering the amount of evaporation generated in the boiler unit 35 so as to be appropriate. ) To control.

  For this reason, it is better to control based on the temperature in the vicinity of the kiln furnace outlet, but as explained in the section of the problem, it is difficult to measure the temperature at the kiln furnace outlet, so it is discharged from the kiln furnace 1. The combustion state of the exhaust gas is the calculated oxygen concentration at the kiln furnace outlet [here, expressed as the oxygen concentration, but should be the amount of oxygen originally, to obtain indirectly by calculation, as described later, Judgment is based on the value of the oxygen amount that is not possible (it is a negative value, which is a case of lack of oxygen), so the term “oxygen index can be used instead of the term“ oxygen concentration ”] Therefore, the obtained oxygen concentration is controlled to be within a set range obtained in advance through experiments or the like.

  That is, combustion is actively performed at the kiln furnace outlet, and it is difficult to measure the temperature with a measuring instrument. Therefore, as will be described later, oxygen of exhaust gas finally discharged from the gas discharge cylinder 57 is used. From the amount of residual oxygen in the exhaust gas determined from the concentration and the amount of oxygen contained in the air supplied from outside in the stoker furnace 2 and the exhaust gas treatment facility 3, the amount of oxygen at the kiln furnace outlet is obtained, The oxygen amount is divided by the amount of exhaust gas at the exit of the kiln furnace determined from the amount of exhaust gas discharged from the exhaust gas treatment facility 3 and the amount of combustion air supplied from the outside in the stoker furnace 2 and the exhaust gas treatment facility 3. The oxygen concentration (oxygen index) at the outlet is obtained.

Hereinafter, the control device 4 will be described by focusing on the kiln furnace side air supply control unit 92 that controls the combustion air to the kiln furnace 1 according to the gist of the present invention.
The kiln furnace side air supply control unit 92 is provided with a kiln furnace oxygen concentration calculation unit for obtaining the oxygen concentration at the kiln furnace outlet. Hereinafter, the kiln furnace oxygen concentration calculation unit will be described.

  As shown in FIG. 3, the kiln furnace oxygen concentration calculation unit (corresponding to the oxygen calculation unit described in the claims) 101 is provided in the third, fourth, and fourth portions provided in the air supply pipes 40, 43, and 63. Measured values from the sixth flow meters 45, 46 and 72 (the amount of air to the stoker furnace wind box, the amount of air to the stoker furnace secondary combustion chamber, the amount of air to the temperature control tower), the air supply pipe 64 and the chemical The other known air amount, which is a constant amount supplied from the injection pipe 66, is inputted, and an air amount adding unit 102 for obtaining the total (all the parts behind the kiln furnace) and a fifth part in the middle of the exhaust gas outlet pipe 56 The total amount of supplied air determined by the air amount adding unit 102 is subtracted from the amount of exhaust gas discharged by the flow meter 71 (the total amount of exhaust gas discharged from the combustion facility) and discharged from the kiln furnace 1. The amount of exhaust gas discharged from the kiln furnace Behind the kiln furnace to obtain the amount of oxygen supplied by multiplying the total supply air amount obtained by the kiln furnace outlet exhaust gas amount calculation unit 103 and the air amount addition unit 102 by the oxygen concentration (21%) in the air. The amount of discharged exhaust gas measured by the supplied oxygen amount calculation unit 104 and the fifth flow meter 71 provided in the gas outlet pipe 56 is multiplied by the oxygen concentration value measured by the oxygen concentration meter 73 to increase the amount of exhaust gas in the exhaust gas. The residual oxygen amount calculation unit 105 for determining the residual oxygen amount contained in the residual oxygen amount is subtracted from the residual oxygen amount determined by the residual oxygen amount calculation unit 105 from the kiln furnace. A kiln furnace outlet oxygen amount calculation unit 106 for obtaining an oxygen amount at the kiln furnace outlet (corresponding to a difference value described in claims), and a kiln furnace outlet exhaust gas amount obtained by the kiln furnace outlet exhaust gas amount calculator 103. The oxygen concentration calculating unit 107 calculates the ratio (B / A) of the kiln furnace outlet oxygen amount B obtained by the kiln furnace outlet oxygen amount calculating unit 106 to obtain the oxygen concentration at the kiln furnace outlet. .

  That is, the kiln furnace oxygen concentration calculation unit 101 supplies oxygen supplied from the stoker furnace 2 and the exhaust gas treatment facility 3 downstream from the kiln furnace 1 based on the amount of residual oxygen obtained from the amount of exhaust gas discharged and the oxygen concentration thereof. By subtracting the amount, the amount of oxygen at the kiln furnace outlet is obtained, and the value obtained by dividing the amount of oxygen by the amount of exhaust gas discharged from the kiln furnace 1 is obtained as the oxygen concentration.

  Then, by controlling the combustion air supplied to the kiln furnace 1 so that the oxygen concentration is within a predetermined range, combustion in the kiln furnace 1 is favorably performed and the kiln furnace 1 is changed to the stoker furnace 2. While supplying an appropriate amount of exhaust gas at an appropriate temperature, the boiler unit 35 is configured to obtain a predetermined evaporation amount.

Next, the kiln furnace side air supply control unit 92 will be described in detail with reference to FIG.
In the kiln furnace side air supply control unit 92, control is performed using the properties of the waste, the furnace temperature of the kiln furnace 1, the amount of evaporation in the boiler unit 35, and the oxygen concentration at the kiln furnace outlet.

  Specifically, regarding the properties of the waste, a correction coefficient is determined from the RDF input amount, the wood waste input amount, the mixed waste input amount, the sludge input amount, the oil mud input amount, and the liquid sludge input amount. Used. This correction coefficient is obtained from a graph (input ratio-correction coefficient) obtained in advance for each type and according to the input ratio (%). For example, when several types are mixed. The average value of the obtained correction coefficients is used. Note that the correction coefficient is small for those with high calories (so-called clinker generation), and conversely, those with low calories are increased.

Moreover, about the temperature in the kiln furnace 1, the moving average value of the measured temperature measured by the 2nd thermometer 29 installed in the 2nd point (b) is used.
Further, as the evaporation amount in the boiler unit 35, the measured evaporation amount measured by the steam flow meter 50 provided in the middle of the steam extraction pipe 49 to the demand facility for the steam generated in the boiler unit 35 is used.

  As shown in FIG. 4, the kiln furnace-side air supply control unit 92 roughly determines the amount of air supplied to the previous stage based on the set evaporation amount set by the evaporation amount setting unit 91, and the kiln furnace 1. The first-stage supply air amount calculation unit 111 that corrects the first-stage air amount based on the temperature at the second point (b) measured by the second thermometer 29 and calculates the amount of air supplied to the first stage of the kiln furnace 1. And determining the amount of air to be supplied to the intermediate stage based on the set evaporation amount similarly set by the evaporation amount setting unit 91, and for the intermediate stage air amount based on the measured evaporation amount and the obtained oxygen concentration at the kiln furnace outlet. And an intermediate stage supply air amount calculation unit 112 that calculates the amount of air supplied to the intermediate stage of the kiln furnace 1.

  The preceding stage supply air amount calculation unit 111 has a function for determining the amount of air to be supplied to the previous stage with respect to the set evaporation amount set by the evaporation amount setting unit 91, and from the inputted set evaporation amount, the preceding stage air amount To set a correction coefficient for changing the calorific value in accordance with the pre-stage air amount setting unit 121 for setting (pre-stage set air amount) and the property of the waste (for example, solid content, moisture, mud, etc.) The waste property correction coefficient setting unit 122 and the preceding air amount set by the preceding air amount setting unit 121 are input and multiplied by the correction coefficient set by the waste property correction coefficient setting unit 122. (1) A property correction unit 123 for obtaining a pre-stage correction air amount and a target temperature at the second point (b) of the kiln furnace 1 [Of course, a temperature range that does not generate clinker or the like and is suitable for gasification. The target temperature setting unit 124 for setting (for example, a temperature value within 600 to 900 ° C.) and the measured temperature from the second thermometer 29 provided at the second point (b) of the kiln furnace 1 are set. A temperature moving average calculation unit 125 that inputs and calculates the moving average value, and a temperature deviation calculation that calculates a deviation by inputting the target temperature from the target temperature setting unit 124 and the moving average value from the temperature moving average calculation unit 125 And a temperature correction coefficient calculation unit 127 that has a function for determining a correction value of the air amount with respect to the temperature deviation obtained by the temperature deviation calculation unit 126 and calculates a temperature correction coefficient from the input deviation. A temperature correction unit 128 that corrects the first pre-stage correction air amount obtained by the property correction unit 123 by the temperature correction coefficient obtained by the temperature correction coefficient calculation unit 127, and the temperature correction. In consideration of the upper limit value set in advance for the second front-stage corrected air amount corrected at 128, the final front-stage supply air amount (of course, the second front-stage supply air amount supplied to the front stage (the front-stage air supply nozzle of the hood section)) And a final pre-stage air amount calculation unit 129 that calculates the upper limit value when the pre-stage correction air amount exceeds the upper limit value.

  Therefore, the final pre-stage supply air amount obtained by the final pre-stage air amount calculation unit 129 is output to a control unit of a damper (not shown), and an opening degree command that can supply the final pre-stage supply air amount is output from the control unit. It is output to the second damper 27.

  The intermediate stage supply air amount calculation unit 112 has a function for determining the amount of air to be supplied to the intermediate stage with respect to the set evaporation amount set by the evaporation amount setting unit 91, and from the input set evaporation amount. The intermediate stage air amount setting unit 131 for setting the intermediate stage air amount (intermediate stage set air amount), the intermediate stage air amount set by the intermediate stage air amount setting unit 131 and the preceding stage air amount setting unit 121 are set. The air amount adding unit 132 for adding the previous air amount, the total air amount obtained by the air amount adding unit 132, and the first pre-stage corrected air amount corrected by the property correcting unit 123 The intermediate stage air amount correction unit 133 that corrects the intermediate stage air amount by subtracting the first front stage correction air amount, and the initial adjustment is performed according to the situation at the time of initial operation of the rotary kiln furnace 1 or operation start after maintenance. Needed The adjustment coefficient corresponding to the initial adjustment is set (if the initial adjustment is not necessary, the adjustment coefficient is set to 1.0) and the intermediate stage air amount correction unit 133. The first intermediate stage air amount correction is performed by inputting the intermediate stage air amount obtained in step 1 and the adjustment coefficient set by the adjustment coefficient setting unit 134 and correcting the air amount by multiplying the intermediate stage air amount by the adjustment coefficient. 135, a kiln furnace outlet target oxygen concentration setting unit 136 for setting a target oxygen concentration at the outlet of the kiln furnace 1, a target oxygen concentration from the kiln furnace outlet target oxygen concentration setting unit 136, and the kiln furnace oxygen concentration calculator When the oxygen concentration deviation calculating unit 137 which inputs the kiln furnace outlet oxygen concentration obtained in 101 and obtains the deviation thereof, and the deviation obtained by the oxygen concentration deviation calculating unit 137 are input. A PID calculation unit 138 for obtaining a PID control coefficient based on the deviation, a first intermediate stage correction air amount obtained by the first intermediate stage air amount correction unit 135, and a control coefficient from the PID calculation unit 138 are input. And a second intermediate stage air amount correction unit (corresponding to the oxygen correction unit described in the claims, which further corrects the air amount by multiplying the first intermediate stage correction air amount by the control coefficient). 139, and the set evaporation amount in the boiler unit 35 and the measured evaporation amount measured by the steam flow meter 50 are input to obtain the deviation of the evaporation amount. A calculation unit 140, a PID calculation unit 141 for inputting a deviation obtained by the evaporation amount deviation calculation unit 140 and obtaining a PID control coefficient based on the deviation, and the second intermediate stage air amount The second intermediate stage correction air amount obtained by the correction unit 139 and the control coefficient from the PID calculation unit 141 are input, and the second intermediate stage correction air amount is multiplied by the control coefficient to thereby calculate the air amount based on the evaporation amount. And a final intermediate stage air amount calculation unit (corresponding to an evaporation amount correction unit described in claims) 142 for obtaining the final intermediate stage supply air amount to be finally supplied to the intermediate stage.

  Therefore, the final intermediate stage supply air amount obtained by the final intermediate stage air amount calculation unit 142 is output to a damper control unit (not shown), from which the final intermediate stage supply air amount can be supplied. A degree command is output to the first damper 26.

Next, a combustion air supply control method by the control device 4 will be described.
Since the gist of the present invention is a combustion air supply control method on the kiln furnace side, the following description will be focused on the kiln furnace 1 side.

  Briefly explaining the control of the supply air amount in the kiln furnace 1, the combustion residue discharged from the kiln furnace 1 and the unburned portion of the exhaust gas are guided to the stalker furnace 2 side and completely burned. In order to prevent an increase in the combustion load at the kiln, combustion is performed with an appropriate amount of air on the kiln furnace 1 side, and at the time of this combustion, the temperature on the kiln furnace 1 side is not excessively increased, that is, the kiln furnace. The clinker is prevented from being generated in the inside.

  Then, the combustion state in the kiln furnace 1, particularly the combustion state at the kiln furnace outlet, is determined based on the oxygen concentration at the outlet, and the amount of air to be supplied so that the oxygen concentration falls within a predetermined range. Is to control.

First, the type of waste, the input ratio, and the like are input to the waste input amount determination unit 81 to determine the input amount of waste (so-called planned processing amount).
Then, after the input amount is input to the kiln furnace rotation speed setting unit 82 and the rotation speed of the kiln furnace 1 is set, the set rotation speed is input to the kiln furnace rotation speed control unit 84 and the kiln furnace 1 The rotation speed is controlled.

  In addition, after the input amount is input to the waste supply speed setting unit 83 and the supply speed in the waste supply device 15 provided in the kiln furnace 1 is set, the set supply speed is determined as the waste supply speed control unit. 85 is input to control the waste supply rate.

Further, after the input amount is input to the evaporation amount setting unit 91 and the evaporation amount in the boiler unit 35 is set, the set evaporation amount is input to the kiln furnace side air supply control unit 92.
Next, control in the kiln furnace side air supply control unit 92 will be described.

  The set evaporation amount is input to the front-stage air amount setting unit 121 and the intermediate-stage air amount setting unit 131, and is input to the front-stage part (the front-stage air supply nozzle 16) and the intermediate-stage part (the intermediate-stage air supply nozzle 18) of the kiln furnace 1. Based on a predetermined function for each of the supplied air amounts, a preceding stage air amount (an earlier stage set air amount) and an intermediate stage air amount (an intermediate stage set air amount) are obtained as initial values.

Then, the upstream air amount is input to the property correcting unit 123, where the first waste air amount is obtained by multiplying the waste property correcting coefficient set in advance.
The first pre-stage correction air amount is input to the temperature correction unit 128, and the measured temperature from the second thermometer 29 provided at the second point (b) of the furnace body 11 of the kiln furnace 1 and the target temperature are calculated. The second correction air amount is obtained by multiplying the temperature correction coefficient obtained based on the deviation.

  Then, the second pre-stage corrected air amount is input to the final pre-stage air amount calculation unit 129 and compared with the upper limit value. If the upper limit value is not exceeded, the second pre-stage corrected air amount remains the final pre-stage supply air amount. If the upper limit value is exceeded, the upper limit value is determined as the final pre-stage supply air amount, and the final pre-stage supply air amount is output to the control unit of a predetermined damper, and the final pre-stage supply is supplied from the control unit. An opening degree command corresponding to the amount of air is output to the second damper 27.

  In this way, correction is made based on the property of the waste with respect to the amount of the previous stage air to be supplied to the front stage side of the kiln furnace 1 set based on the set evaporation amount in the boiler unit 35, and the end portion of the previous stage, that is, the middle Since the correction is performed so that the temperature in the furnace at the start end of the stage becomes a target temperature at which no clinker is generated, combustion on the front stage side in the kiln furnace 1 can be performed satisfactorily.

  On the other hand, the intermediate stage air amount is input to the air amount adding unit 132, and the total air amount of the previous stage air amount and the intermediate stage air amount is obtained, and then input to the intermediate stage air amount correcting unit 133. The first upstream correction air amount is subtracted from the air amount, and the correction amount of the upstream air amount is corrected. That is, when the amount of air in the front stage is increased by the property correcting unit 123, the amount of air in the upstream stage is reduced from the amount of air in the middle stage, and the total amount of air supplied to the kiln furnace 1 is adjusted to be constant. (The increase in the amount of exhaust gas is prevented). Needless to say, conversely, when the previous stage air amount is decreased by the property correcting unit 123, the intermediate stage air amount is increased by the reduced amount.

  Next, the adjusted intermediate stage air amount is input to the first intermediate stage air amount correction unit 135, where the intermediate stage air amount is multiplied by an adjustment coefficient corresponding to the initial operation state in the kiln furnace 1. It is corrected.

  The corrected first intermediate stage air correction amount is input to the second intermediate stage air amount correction unit 139, where the oxygen concentration at the kiln furnace outlet and the target oxygen concentration obtained by the kiln furnace oxygen concentration calculation unit 101 are calculated. Further correction is performed based on the deviation.

  Further, the corrected second intermediate stage corrected air amount is input to the final intermediate stage air amount calculating unit 142, where, based on the deviation between the measured evaporation amount and the target evaporation amount in the boiler unit 35 of the stoker furnace 2, Correction is performed.

  With these corrections, the amount of exhaust gas from the kiln furnace 1 is set so that the combustion state on the rear stage side of the kiln furnace 1 is maintained well and the amount of evaporation in the boiler section 35 in the stoker furnace 1 becomes the target evaporation amount. Be controlled.

  Then, the final intermediate stage air amount calculation unit 142 outputs the final intermediate stage supply air amount to a control unit of a predetermined damper, and an opening degree command corresponding to the final intermediate stage supply air amount is first output from the control unit. It is output to the damper 26.

  In this way, the intermediate stage air amount to be supplied to the intermediate stage side of the kiln furnace 1 set based on the set evaporation amount in the boiler unit 35 is corrected based on the oxygen concentration at the kiln furnace outlet in particular. Since the correction is performed so that the evaporation amount in the boiler section 35 of the stoker furnace 2 becomes the target evaporation amount, the combustion state on the rear stage side of the kiln furnace 1 can be maintained well.

  Here, the results of experiments using the above-described supply control method will be briefly described with reference to FIG. FIG. 5A shows a schematic configuration of the rotary kiln furnace, and FIG. 5B shows the furnace temperature at a position (distance from the kiln furnace supply port) corresponding to the drawing of FIG.

  In FIG. 5, circles indicate the case of the air supply control method (air supply to the previous stage + air supply to the intermediate stage) according to the present invention, and triangles indicate the case where the air supply is performed only to the previous stage. The square marks indicate the case where air is supplied only to the intermediate stage. The horizontal axis indicates the distance (position) from the kiln furnace supply port, and the vertical axis indicates the furnace temperature measured at each point.

  From FIG. 5, if air is supplied only to the previous stage, air is supplied only to the portion between the first point (b) and the second point (b). It can be seen that at the second point (b), the furnace temperature exceeds 1200 ° C. and then decreases.

  In addition, if the air is supplied only to the intermediate stage, a rapid increase in temperature is not seen in the portion between the first point (A) and the second point (B) before supplying air, In the portion between the second point (b) and the third point (c) where the air supply is performed, the temperature rapidly rises, and at the third point (c), it reaches nearly 1200 ° C., and further the third point (c) ) And the fourth point (d), the temperature rises and exceeds 1200 ° C. at the kiln furnace outlet, which is the fourth point (d).

  On the other hand, when air is supplied to the front side and the intermediate side by the supply control method of the present invention, the first point (A) to the second point (B), and the second point (B) to the second point. It can be clearly seen that the temperature gradually increases in the portion between the three points (c), and even if it reaches the kiln furnace outlet, which is the fourth point (d), it is suppressed to a little higher than 1000 ° C. In addition, the horizontal line of the broken line in FIG.5 (b) has shown the generation temperature (about 1100 degreeC) of clinker.

That is, in the rotary kiln furnace, an appropriate combustion state can be obtained without appropriately generating air by distributing air appropriately to the front stage side and the intermediate stage side.
By the way, in the said embodiment, after adjusting based on the adjustment coefficient of intermediate | middle stage air quantity, it correct | amends based on the oxygen concentration of a kiln furnace exit, and performs correction | amendment based on the evaporation amount in a boiler part after that. As described above, the order of these adjustments and corrections can be changed as appropriate.

It is a figure which shows schematic structure of the waste combustion equipment which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of the control apparatus in the waste combustion facility. It is a block diagram which shows schematic structure of the kiln furnace oxygen concentration calculating part in the same control apparatus. It is a block diagram which shows schematic structure of the kiln furnace side air supply control part in the same control apparatus. It is a figure which shows the temperature in the rotary kiln furnace at the time of using the supply control method of the combustion air which concerns on embodiment of this invention, (a) is a schematic sectional drawing of a rotary kiln furnace, (b) is a kiln furnace It is a graph which shows the furnace temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary kiln furnace 2 Stoker furnace 3 Exhaust gas treatment facility 4 Control apparatus 11 Furnace main body 14 Hood part 15 Waste supply apparatus 16 Pre-stage air supply nozzle 18 Intermediate stage air supply nozzle 19 Kiln side air supply apparatus 24 1st flow meter 25 2nd Flow meter 26 First damper 27 Second damper 29 Second thermometer 35 Boiler part 36 Grating air supply device 37 Secondary combustion chamber air supply device 45 Third flow meter 46 Fourth flow meter 56 Exhaust gas outlet pipe 57 Gas Discharge tube 71 Fifth flow meter 72 Sixth flow meter 73 Oxygen concentration meter 81 Waste input amount determination unit 82 Kiln furnace rotation speed setting unit 83 Waste supply speed setting unit 84 Kiln furnace rotation speed control unit 85 Waste supply speed control Unit 91 Evaporation amount setting unit 92 Kiln furnace side air supply control unit 93 Stoker furnace side air supply control unit 101 Kiln furnace oxygen concentration Calculation unit 102 Air amount addition unit 103 Kiln furnace outlet exhaust gas amount calculation unit 104 Supply oxygen amount calculation unit 105 Residual oxygen amount calculation unit 106 Kiln furnace outlet oxygen amount calculation unit 107 Oxygen concentration calculation unit 111 Pre-stage supply air amount calculation unit 112 Intermediate stage Supply air amount calculation unit 121 Pre-stage air amount setting unit 122 Waste property correction coefficient setting unit 123 Property correction unit 124 Target temperature setting unit 125 Temperature moving average calculation unit 126 Temperature deviation calculation unit 127 Temperature correction coefficient calculation unit 128 Temperature correction unit 129 Final pre-stage air amount calculation unit 131 Intermediate stage air amount setting unit 132 Air amount addition unit 133 Intermediate stage air amount correction unit 134 Adjustment coefficient setting unit 135 First intermediate stage air amount correction unit 136 Kiln furnace outlet target oxygen concentration setting unit 137 Oxygen Concentration deviation calculation unit 138 PID calculation unit 139 Second intermediate stage air amount correction unit 140 Evaporation amount deviation calculation unit 14 PID operator 142 final intermediate-stage air amount computing unit

Claims (6)

A rotary kiln that is a primary combustion furnace for burning waste, and a secondary combustion furnace having a boiler section that further burns unburned portions of combustion residues and exhaust gas discharged from the rotary kiln furnace and recovers waste heat A method for controlling the supply of combustion air to the rotary kiln furnace in a waste combustion facility having an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace,
For the amount of air supplied to the rotary kiln furnace set in advance based on the amount of waste input,
Oxygen obtained by subtracting the residual oxygen amount discharged from the exhaust gas treatment facility from the oxygen amount supplied to the secondary combustion furnace and the exhaust gas treatment facility and dividing the difference value by the air amount supplied to the rotary kiln furnace A method for controlling the supply of combustion air to a rotary kiln furnace, wherein the correction is performed with oxygen so that the concentration falls within a preset setting range. A rotary kiln that is a primary combustion furnace for burning waste, and a secondary combustion furnace having a boiler section that further burns unburned portions of combustion residues and exhaust gas discharged from the rotary kiln furnace and recovers waste heat A method for controlling the supply of combustion air to the rotary kiln furnace in a waste combustion facility having an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace,
Based on the set evaporation amount in the boiler section obtained from the input amount of waste, the pre-stage air amount as the pre-set amount to be supplied to the pre-stage side of the rotary kiln furnace and the intermediate stage as the pre-set amount to be supplied to the intermediate stage side Find the air volume,
Pre-stage supply air quantity supplied to the pre-stage side by correcting the temperature so that the measured temperature measured on the pre-stage side of the rotary kiln is within a preset setting range with respect to the pre-stage air quantity. Seeking
The air supplied to the rotary kiln furnace by subtracting the residual oxygen amount discharged from the exhaust gas treatment facility from the oxygen amount supplied to the secondary combustion furnace and the exhaust gas treatment facility with respect to the intermediate stage air amount. The rotary kiln is characterized in that an intermediate stage supply air amount to be supplied to the intermediate stage is obtained by performing correction with oxygen so that the oxygen concentration obtained by dividing by the quantity is within a preset setting range. A method for controlling the supply of combustion air to a furnace.   The rotary according to claim 2, wherein the correction based on the evaporation amount is performed so that the measured evaporation amount in the boiler unit becomes a preset evaporation amount with respect to the corrected intermediate stage air amount. Combustion air supply control method to kiln furnace. A rotary kiln that is a primary combustion furnace that burns waste, a secondary combustion furnace that has a boiler part that burns the unburned portion of the combustion residue and exhaust gas discharged from the rotary kiln and recovers waste heat; A supply control device for combustion air to the rotary kiln furnace in a waste combustion facility having an exhaust gas treatment facility for treating exhaust gas discharged from the secondary combustion furnace,
The amount of air to be supplied to the front stage air amount setting unit and the intermediate stage side for setting the amount of air to be supplied to the front stage side of the rotary kiln furnace based on the set evaporation amount in the boiler section obtained from the input amount of waste An intermediate air amount setting section to be set;
Correction is made so that the measured temperature measured by the thermometer provided on the front stage side of the rotary kiln is within a preset setting range with respect to the front stage air quantity obtained by the preceding stage air quantity setting unit. A temperature correction unit to perform,
The oxygen concentration is obtained by dividing the difference obtained by subtracting the amount of residual oxygen discharged from the exhaust gas treatment facility from the amount of oxygen supplied to the secondary combustion furnace and the exhaust gas treatment facility by the amount of air supplied to the rotary kiln furnace. An oxygen calculation unit to be obtained;
An oxygen correction unit for correcting the intermediate stage set air amount obtained by the intermediate stage air quantity setting unit so that the value obtained by the oxygen calculation unit is within a preset setting range; A supply control apparatus for combustion air to a rotary kiln furnace. An evaporation amount deviation calculating unit for obtaining a deviation between the set evaporation amount and the measured evaporation amount in the boiler unit;
An evaporation amount correction unit that inputs the intermediate stage correction air amount corrected by the oxygen correction unit and further corrects the intermediate stage correction air amount so that the deviation obtained by the evaporation amount deviation calculation unit is eliminated. The supply control apparatus of the combustion air to the rotary kiln furnace of Claim 4 characterized by the above-mentioned. Oxygen calculator
An air amount adding unit for adding the respective air amounts measured by flow meters provided in the secondary combustion furnace and the exhaust gas treatment facility to obtain a total supply air amount supplied behind the rotary kiln furnace;
A supply oxygen amount calculation unit that obtains an oxygen amount included in the total supply air amount by multiplying the total supply air amount obtained by the air amount addition unit by the oxygen concentration of the supplied air;
A kiln for subtracting the total supply air amount obtained by the supply air amount calculation unit from the total exhaust gas amount measured by a flow meter provided at the rear stage of the exhaust gas treatment facility to obtain the exhaust gas amount at the kiln furnace outlet A furnace outlet exhaust gas amount calculation unit;
A residual oxygen amount calculation unit for obtaining the residual oxygen amount in the total exhaust gas by multiplying the total exhaust gas amount by the oxygen concentration measured by an oxygen concentration meter provided on the rear stage side of the exhaust gas treatment facility;
A kiln furnace outlet oxygen amount calculation unit for subtracting the supply oxygen amount determined by the supply oxygen amount calculation unit from the residual oxygen amount determined by the residual oxygen amount calculation unit to obtain the kiln furnace outlet oxygen amount;
An oxygen concentration calculation unit for determining the oxygen concentration by dividing the kiln furnace outlet oxygen amount determined by the kiln furnace outlet oxygen amount calculation unit by the exhaust gas amount determined by the kiln furnace outlet exhaust gas amount calculation unit. The supply control apparatus of the combustion air to the rotary kiln furnace of Claim 5 characterized by the above-mentioned.

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