JP3746751B2 - Control method and control apparatus for sludge combustion furnace - Google Patents

Description

【００２１】
更に制御部には動作信号生成手段を有しており、前記補正値αに基づいて調節操作量を生成して、各調節弁もしくは調節器の動作信号を出力する。そのロジック図を図２〜５にそれぞれ燃焼空気、二次空気、助燃料の各量及び燃焼空気温度について示す。
【００２２】
図２により燃焼空気流量調節の例で説明すると、ファジィ演算補正値αは、汚泥ケーキ量設定値（ＳＶ、セットヴァリュ）をファンクションジェネレ−タ２０に入力して燃焼空気流量設定値に変換した信号と加算器２１で加算され、補正燃焼空気流量設定値を得る。補正燃焼空気流量設定値と燃焼空気流量工程値（ＰＶ、プロセスヴァリュ）はＰＩＤ回路２２に入力され、ＰＩＤ動作により燃焼空気流量調節弁の操作信号を出力し、燃焼空気流量調節弁１１の開度を調節する。以下二次空気、助燃料の各量及び燃焼空気温度についても図３〜５において同様である。
【００２３】
図３は本発明の汚泥燃焼炉の制御における、二次空気流量調節のロジック図である。図３において、ファジィ演算補正値αは、汚泥ケーキ量設定値（ＳＶ、セットヴァリュ）をファンクションジェネレータ２０に入力して二次空気流量設定値に変換した信号と加算器２１で加算され、補正二次空気流量設定値を得る。補正二次空気流量設定値と二次空気流量工程値（ＰＶ、プロセスヴァリュ）はＰＩＤ回路２２に入力され、ＰＩＤ動作により二次空気流量調節弁９の開度を調節する。
【００２４】
図４は本発明の汚泥燃焼炉の制御における、燃焼空気温度調節のロジック図である。図４において、ファジィ演算補正値αは、汚泥ケーキ量設定値（ＳＶ、セットヴァリュ）をファンクションジェネレータ２０に入力して燃焼空気温度設定値に変換した信号と加算器２１で加算され、補正燃焼空気温度設定値を得る。補正燃焼空気温度設定値と燃焼空気温度工程値（ＰＶ、プロセスヴァリュ）はＰＩＤ回路２２に入力され、ＰＩＤ動作により燃焼空気温度調節器１２の操作信号を出力し、ヒータ１３により燃焼空気温度を調節する。
【００２５】
図５は本発明の汚泥燃焼炉の制御における、助燃料流量調節のロジック図である。図５において、ファジィ演算補正値αは、汚泥ケーキ量設定値（ＳＶ、セットヴァリュ）をファンクションジェネレータ２０に入力して助燃料流量設定値に変換した信号と加算器２１で加算され、補正助燃料流量設定値を得る。補正助燃料流量設定値と助燃料流量工程値（ＰＶ、プロセスヴァリュ）はＰＩＤ回路２２に入力され、ＰＩＤ動作により燃料流量調節弁１１の開度を調節する。
【００２６】
【発明の効果】
以上説明したように、本発明により、下水汚泥燃焼炉の燃焼ガス中のＮ_２Ｏを直接測定して、リアルタイムに燃焼条件に反映させて、その排出濃度を低減する燃焼炉の新しい制御方法及び制御装置の提供が可能となった。
【図面の簡単な説明】
【図１】 本発明の汚泥燃焼炉を含む、汚泥燃焼炉の制御装置の概略構成図
【図２】 本発明の汚泥燃焼炉の制御における、燃焼空気量調節のロジック図
【図３】 本発明の汚泥燃焼炉の制御における、二次空気流量調節のロジック図
【図４】 本発明の汚泥燃焼炉の制御における、燃焼空気温度調節のロジック図
【図５】 本発明の汚泥燃焼炉の制御における、助燃料流量調節のロジック図
【符号の説明】
１ 汚泥燃焼炉
２ 制御部
３ レーザ式濃度計
４ レーザ受光部
５ レーザ発光部
６ 酸素濃度計
７ フリーボード温度計
８ 砂層温度計
９ 二次空気調節弁
１０ 助燃料調節弁
１１ 燃焼空気調節弁
１２ 燃焼空気温度調節器
２０ ファンクションジェネレータ
２１ 加算器
２２ ＰＩＤ回路[0001]
[Field of the Invention]
The present invention relates to a control method and control device for a combustion furnace for burning sludge. More particularly, the present invention relates to a combustion furnace control method and control apparatus for reducing N ₂ O in exhaust gas of a combustion furnace that burns sludge.
[0002]
[Prior art]
Global warming nitrous oxide known as a gas (hereinafter N _{2 O)} is by far the reasons such as was not a gas regulated emissions concentration measurement and an exhaust gas N ₂ O in the sewage sludge combustion furnace Combustion control by concentration has not been performed. However, N 2 _O is on that has been known to produce about 300 times the warming effect of CO _2, sewage sludge number in the combustion exhaust gas from the rich in nitrogen component hundred ppm higher N ₂ Since it contains O, it is desired to reduce N ₂ O discharged from the sewage sludge combustion furnace as much as possible.
[0003]
Therefore, the technology for controlling the exhaust gas N ₂ O concentration in the sewage sludge combustion furnace has not been publicly known so far, and even in the method of detecting the control substance in the combustion gas in real time, for example, in the detection of the CO concentration An example can be seen (see, for example, paragraph 0039 of Patent Document 1), but the detection of the N ₂ O concentration is not yet publicly known.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-14027 (see, for example, paragraph 0039)
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of such conventional problems. Combustion in which N ₂ O in combustion gas of a sewage sludge combustion furnace is directly measured and reflected in combustion conditions in real time to reduce its exhaust concentration. An object is to provide a new method and apparatus for controlling a furnace.
[0006]
[Means for Solving the Problems]
A control method for a sludge combustion furnace according to the present invention is a control method for a combustion furnace in which auxiliary fuel and combustion air are supplied together with sludge to burn the sludge, and the N ₂ O concentration in the combustion gas is detected and detected. Based on the value, calculate a correction value of at least one operation amount selected from the combustion air amount, the secondary air amount, the combustion air temperature, and the auxiliary fuel flow rate, and adjust the operation amount based on the calculated value, It is characterized by reducing N ₂ O in the exhaust gas of the combustion furnace.
[0007]
Furthermore, the control method of the sludge combustion furnace of the present invention is a combustion furnace for burning the sludge by supplying auxiliary fuel and combustion air together with the sludge, and combusting by forming a bubble fluidized bed with the sludge using sand particles as a heat medium. In the control method for a combustion furnace, the N ₂ O concentration in the combustion gas, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the free board are detected, and the combustion air is detected based on the detected values. A correction value of at least one manipulated variable selected from the amount, the secondary air amount, the combustion air temperature, and the auxiliary fuel flow rate is calculated, and the manipulated variable is adjusted based on the calculated value, and N in the exhaust gas of the combustion furnace is calculated. ₂ O is reduced.
[0008]
Further, the control method for sludge combustion furnace of the present invention, the N _{2 O} concentration in the combustion gas, in the combustion gas is irradiated with laser light of a specific wavelength in the near infrared wavelength region, N ₂ in the laser beam It is obtained by measuring the absorbance of a specific wavelength that O absorbs.
[0009]
Furthermore, in the control method of the sludge combustion furnace of the present invention, the calculation of the correction value includes the detected N ₂ O concentration in the combustion gas, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the free board. The antecedent part is based on a calculation based on fuzzy inference with the combustion air amount, the secondary air amount, the combustion air temperature, and the auxiliary fuel flow rate as the consequent part.
[0010]
Furthermore, in the control method of the sludge combustion furnace of the present invention, the adjustment of each operation amount is obtained by adding the correction value to the operation amount setting value generated by inputting a predetermined input sludge amount into the function generator. The correction operation amount setting value and the operation amount process value are performed by a PID operation.
[0011]
Further, the control unit of the sludge combustion furnace of the present invention is the control device for a combustion furnace by supplying combustion air with the aid fuel with sludge burning the sludge, N ₂ O for detecting the N _{2 O} concentration in the combustion gas A concentration meter, an operation amount detection means for detecting at least one operation amount selected from a combustion air amount, a secondary air amount, a combustion air temperature, and an auxiliary fuel flow rate, and the operation amount based on the N ₂ O concentration detection value A control unit having a correction value calculation means for calculating a correction value of the control signal and an operation signal generation means for generating an operation signal of the correction manipulated variable based on the calculated correction value. N ₂ O in exhaust gas is reduced.
[0012]
Furthermore, the control device for the sludge combustion furnace of the present invention is a combustion furnace that burns the sludge by supplying auxiliary fuel and combustion air together with the sludge, and burns by forming a bubble fluidized bed with the sludge using sand particles as a heat medium. the control device of a combustion furnace for the N _{2 O} concentration meter for detecting the concentration of N _{2 O} in the combustion gas, and the oxygen concentration meter that detects the oxygen concentration in the exhaust gas, a thermometer for detecting the temperature of the sand layer, A thermometer for detecting the temperature of the free board, an operation amount detecting means for detecting at least one operation amount selected from a combustion air amount, a secondary air amount, a combustion air temperature, and an auxiliary fuel flow rate, and the N ₂ O concentration detection Correction value calculating means for calculating a correction value for the manipulated variable based on the detected value, the oxygen concentration detection value, the sand particle layer temperature detection value, and the freeboard temperature detection value, and correction based on the calculation correction value Generates an operation amount operation signal And a control unit having an operation signal generating means configured to reduce the N ₂ O in the exhaust gas of the combustion furnace by adjusting the operation amount.
[0013]
Furthermore, the control apparatus for the sludge combustion furnace of the present invention is characterized in that the N ₂ O concentration meter oscillates a laser beam having a specific wavelength in the near-infrared wavelength region and irradiates the combustion gas, and the irradiation The light receiving unit that receives the laser light transmitted through the combustion gas and the intensity before and after the N ₂ O absorption of the received laser light are detected, the absorbance is obtained from the detection result, and the N ₂ O concentration electric signal is obtained. It comprises a laser densitometer for conversion.
[0014]
Furthermore, in the control apparatus for the sludge combustion furnace of the present invention, the correction value calculating means detects the detected N ₂ O concentration in the combustion gas, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the free board. The antecedent part is a correction value calculation means based on a calculation by fuzzy inference with the combustion air amount, the secondary air amount, the combustion air temperature and the auxiliary fuel flow rate as the consequent part.
[0015]
Furthermore, in the control apparatus for the sludge combustion furnace of the present invention, the operation signal generation means inputs a predetermined input sludge amount and generates an operation amount setting value, and adds the operation amount setting value and the correction value. An adder and a PID circuit that inputs a corrected manipulated variable set value generated by the adder and the manipulated variable step value and outputs an operation signal of an adjusted manipulated variable are provided.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, shapes, materials, relative arrangements, and the like of the products described in the present embodiment are merely illustrative examples, not the main purpose of limiting the scope of the present invention unless otherwise specified. .
[0017]
FIG. 1 is a schematic configuration diagram of a control apparatus for a sludge combustion furnace including the sludge combustion furnace of the present invention. First, the sludge combustion process will be described with reference to FIG. The sewage sludge is dehydrated by a dehydration process (not shown) and supplied to the sludge combustion furnace 1 as a sludge cake 14 by a feeder 15. In this embodiment, the sludge combustion furnace 1 is a fluidized bed combustion furnace that burns by forming a bubble fluidized bed together with sludge using sand particles as a heat medium. The auxiliary fuel is heated to the combustion furnace sand layer region through the auxiliary fuel adjustment valve 10 and the combustion air is heated by the heater 13 adjusted by the temperature controller 12, and the discharge pressure of the pump P passes through the combustion air flow rate adjustment valve 11. Are introduced from the bottom of the combustion furnace and burned. The sand particles of the heated sand layer flow together with the supplied sludge cake 14 by the combustion air and the generated combustion gas, and the sludge cake 14 burns while flowing. Furthermore, the sludge cake combustion gas completes combustion with the secondary air supplied through the secondary air control valve 9 while rising in the freeboard. The exhaust gas after combustion passes through the flue 16 from the upper part of the furnace and is discharged to the exhaust gas treatment facility.
[0018]
In this embodiment, in addition to the control device, a sand layer thermometer 8 that detects the temperature of the sand layer region, a free board thermometer 7 that detects the temperature of the free board, and an oxygen concentration meter 6 that detects the exhaust gas oxygen concentration in the flue 16. It has. When passing through the further Furibodo upper combustion gases, and a N _{2 O} concentration meter 17 for detecting the N _{2 O} concentration of the combustion gas. The N ₂ O concentration meter 17 receives the laser light absorbed by the laser light emitting part 5 that emits laser light of a specific wavelength from one end of the combustion gas passage part above the free board and the N ₂ O of the combustion gas passage part. It comprises a laser light receiving unit 4 for detecting the intensity and a laser type densitometer 3 for calculating the concentration from the detection signal and outputting the signal to the control unit. N ₂ O absorbs a wavelength of 1.517 μm, attenuates the irradiation light, reaches the laser light receiving unit 4 and is detected. Further, a control unit 2 is provided which receives these control amounts and combustion condition process values and outputs operation signals necessary for adjusting the air amount, auxiliary fuel amount, air temperature and the like necessary for combustion.
[0019]
Then in the present embodiment, a description will be given of a control method of the combustion furnace to reduce the N 2 _O concentration. The control unit is provided with a correction value calculation means based on a calculation by fuzzy inference, and each of the detected values (N ₂ O, N ₂ O, The grade value of the fuzzy set of O ₂ , Ts, Tf) is input as the antecedent part, and the corrected values α of the combustion air, secondary air, auxiliary fuel, and combustion air temperature are output from the subsequent part.
[0020]
[Table 1]

[0021]
Furthermore, the control unit has an operation signal generating means, generates an adjustment operation amount based on the correction value α, and outputs an operation signal of each control valve or regulator. The logic diagrams are shown in FIGS. 2 to 5 for the amounts of combustion air, secondary air, auxiliary fuel, and combustion air temperature, respectively.
[0022]
The fuzzy calculation correction value α is converted into a combustion air flow rate setting value by inputting the sludge cake amount setting value (SV, set value) to the function generator 20 with reference to FIG. The signal is added by the adder 21 to obtain a corrected combustion air flow rate set value. The corrected combustion air flow rate setting value and the combustion air flow rate process value (PV, process value) are input to the PID circuit 22, and an operation signal of the combustion air flow rate control valve is output by the PID operation to open the combustion air flow rate control valve 11. Adjust the degree. The same applies to the amounts of secondary air, auxiliary fuel, and combustion air temperature in FIGS.
[0023]
FIG. 3 is a logic diagram of secondary air flow rate adjustment in the control of the sludge combustion furnace of the present invention. In FIG. 3, the fuzzy calculation correction value α is added by the adder 21 and the signal obtained by inputting the sludge cake amount setting value (SV, set value) to the function generator 20 and converting it to the secondary air flow rate setting value. Obtain the secondary air flow rate setpoint. The corrected secondary air flow rate setting value and the secondary air flow rate process value (PV, process value) are input to the PID circuit 22, and the opening degree of the secondary air flow rate control valve 9 is adjusted by the PID operation.
[0024]
FIG. 4 is a logic diagram of combustion air temperature adjustment in the control of the sludge combustion furnace of the present invention. In FIG. 4, the fuzzy calculation correction value α is added by the adder 21 with the signal obtained by inputting the sludge cake amount setting value (SV, set value) to the function generator 20 and converting it into the combustion air temperature setting value, and the corrected combustion is performed. Get the air temperature setpoint. The corrected combustion air temperature set value and the combustion air temperature process value (PV, process value) are input to the PID circuit 22, an operation signal of the combustion air temperature controller 12 is output by the PID operation, and the combustion air temperature is adjusted by the heater 13. Adjust.
[0025]
FIG. 5 is a logic diagram of the auxiliary fuel flow rate adjustment in the control of the sludge combustion furnace of the present invention. In FIG. 5, the fuzzy calculation correction value α is added by the adder 21 with the signal obtained by inputting the sludge cake amount setting value (SV, set value) to the function generator 20 and converted into the auxiliary fuel flow rate setting value, and the correction assist value is added. Get the fuel flow setpoint. The corrected auxiliary fuel flow rate setting value and the auxiliary fuel flow rate process value (PV, process value) are input to the PID circuit 22, and the opening of the fuel flow rate control valve 11 is adjusted by the PID operation.
[0026]
【The invention's effect】
As described above, according to the present invention, a new control method for a combustion furnace that directly measures N ₂ O in the combustion gas of a sewage sludge combustion furnace, reflects it in combustion conditions in real time, and reduces its exhaust concentration, and A control device can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a control apparatus for a sludge combustion furnace including the sludge combustion furnace of the present invention. FIG. 2 is a logic diagram for adjusting the amount of combustion air in the control of the sludge combustion furnace of the present invention. Fig. 4 is a logic diagram for adjusting the secondary air flow rate in the control of the sludge combustion furnace of the present invention. Fig. 4 is a logic diagram for adjusting the combustion air temperature in the control of the sludge combustion furnace of the present invention. , Logic diagram of auxiliary fuel flow rate adjustment [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sludge combustion furnace 2 Control part 3 Laser type concentration meter 4 Laser light receiving part 5 Laser light emission part 6 Oxygen concentration meter 7 Free board thermometer 8 Sand layer thermometer 9 Secondary air control valve 10 Auxiliary fuel control valve 11 Combustion air control valve 12 Combustion air temperature controller 20 Function generator 21 Adder 22 PID circuit

Claims (10)

In a control method for a combustion furnace in which auxiliary fuel and combustion air are supplied together with sludge to burn the sludge, the N ₂ O concentration in the combustion gas is detected, and based on the detected value, the amount of combustion air, secondary Calculate a correction value for at least one manipulated variable selected from the air amount, combustion air temperature, and auxiliary fuel flow rate, and adjust the manipulated value based on the calculated value to reduce N ₂ O in the exhaust gas of the combustion furnace A control method for a sludge combustion furnace, characterized in that: In a combustion furnace for supplying auxiliary fuel and combustion air together with sludge and burning the sludge, a method for controlling a combustion furnace that forms a bubble fluidized bed together with sludge using sand particles as a heat medium, and in a combustion gas, The N ₂ O concentration, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the free board are detected, and based on the detected values, the combustion air amount, the secondary air amount, the combustion air temperature, and the assistance are detected. Sludge combustion characterized by calculating a correction value of at least one manipulated variable selected from a fuel flow rate and adjusting the manipulated variable based on the calculated value to reduce N ₂ O in exhaust gas of a combustion furnace How to control the furnace. The N ₂ O concentration in the combustion gas is measured by irradiating the combustion gas with a laser beam having a specific wavelength in the near-infrared wavelength region and measuring the absorbance of the specific wavelength absorbed by the N ₂ O in the laser beam. The control method of the sludge combustion furnace of Claim 1 or 2 characterized by the above-mentioned. The correction value is calculated by using the detected N ₂ O concentration in the combustion gas, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the free board as an antecedent part, and the amount of combustion air and secondary air 3. The method of controlling a sludge combustion furnace according to claim 2, wherein the control method is based on a calculation based on fuzzy inference with the amount, combustion air temperature and auxiliary fuel flow rate as a consequent part. The adjustment of each operation amount is performed by adding the correction value to the operation amount setting value generated by inputting a predetermined input sludge amount into the function generator and the operation amount process value. The control method of the sludge combustion furnace of Claim 1 or 2 performed by PID operation | movement with these. The control device of a combustion furnace for combusting the sludge by supplying combustion air with the aid fuel with sludge, and N _{2 O} concentration meter for detecting the concentration of N _{2 O} in the combustion gases, the combustion air quantity, secondary air quantity An operation amount detection means for detecting at least one operation amount selected from the combustion air temperature and the auxiliary fuel flow rate; and a correction value calculation means for calculating a correction value for the operation amount based on the N ₂ O concentration detection value; A control unit having operation signal generation means for generating an operation signal of a corrected operation amount based on the calculated correction value is provided, and the operation amount can be adjusted to reduce N ₂ O in the exhaust gas of the combustion furnace. A sludge combustion furnace control device. A combustion furnace for supplying auxiliary fuel and combustion air together with sludge to burn the sludge, wherein the control device of the combustion furnace forms a bubble fluidized bed with sludge using sand particles as a heat medium, and burns the sludge. N ₂ O concentration meter for detecting N ₂ O concentration, oxygen concentration meter for detecting oxygen concentration in exhaust gas, thermometer for detecting temperature of sand particle layer, thermometer for detecting freeboard temperature, combustion An operation amount detection means for detecting at least one operation amount selected from an air amount, a secondary air amount, a combustion air temperature, and an auxiliary fuel flow rate, and the N ₂ O concentration detection value, the oxygen concentration detection value, and the sand particle layer A correction value calculation unit that calculates a correction value for the operation amount based on the temperature detection value and a temperature detection value for the free board, and an operation signal generation unit that generates an operation signal for the correction operation amount based on the calculation correction value Control unit having And a control device for the sludge combustion furnace, wherein the operation amount is adjustable to reduce N ₂ O in the exhaust gas of the combustion furnace. The N ₂ O densitometer oscillates a laser beam having a specific wavelength in the near-infrared wavelength region and irradiates the combustion gas with a laser light emitting unit, and receives the laser beam irradiated and transmitted through the combustion gas. a light receiving unit that detects the intensity before and after the N _{2 O} of the received laser beam is absorbed, the detection result determined absorbance than, be formed by a laser densitometer to convert into an electric signal of N 2 _O concentration The control apparatus of the sludge combustion furnace of Claim 6 or 7 characterized by these. The correction value calculation means uses the detected N ₂ O concentration in the combustion gas, the oxygen concentration in the exhaust gas, the temperature of the sand particle layer, and the temperature of the freeboard as an antecedent part, and the amount of combustion air, secondary air 8. The control device for a sludge combustion furnace according to claim 7, wherein the control device is a correction value calculation means based on a calculation based on fuzzy inference with the amount, combustion air temperature and auxiliary fuel flow rate as a consequent part. The operation signal generation means includes a function generator that inputs a predetermined input sludge amount to generate an operation amount setting value, an adder that adds the operation amount setting value and the correction value, and a correction generated by the adder. 8. The control apparatus for a sludge combustion furnace according to claim 6 or 7, further comprising a PID circuit for inputting an operation amount set value and the operation amount process value and outputting an operation signal of an adjusted operation amount. .

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