JP5996762B1 - Waste combustion control method and combustion control apparatus to which the method is applied - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously acquire information related to the calorific value of burning waste in real time with high accuracy, and to control combustion of waste without time delay with respect to the current combustion state. Combustion control of an incinerator based on the following procedure. (1) The calorific value of the waste is estimated from the actually measured component concentration in the combustion exhaust gas. (2) Estimate the amount of boiler evaporation based on the calculated waste heat value. (3) Based on the estimated amount of boiler evaporation, the supply amount of waste, combustion air, and auxiliary combustion material to be charged into the incinerator is controlled. [Selection] Figure 1

Description

  The present invention relates to a waste combustion control method and a combustion control apparatus to which the waste combustion control method is applied, and more particularly to a combustion control method and a combustion control apparatus applicable to a wide variety of wastes.

  Conventionally, combustible waste, such as municipal waste and sewage sludge, has been collected from business establishments and households, transported to waste treatment facilities and waste treatment facilities in each region, and burned And then disposed of as purified exhaust gas or incinerated ash. At this time, since the properties of waste such as oil and gas are known, it is possible to perform stable combustion control. In actual facilities, the amount of combustion air is adjusted in advance to the amount of combustion of waste. This is achieved by adjusting to the set value. On the other hand, the properties of various wastes are not uniform, and it is not easy to stably burn them. For this reason, there is a need for a combustion incinerator combustion control method that can prevent the generation of unburned matter and stabilize the combustion state in the furnace. In order to maintain the operation in which the steam generation amount is constant, automatic combustion control is performed using the combustion air amount, the cooling air amount, the feed rate, the grate speed, and the like as indexes. As a conventional specific control method, various new control methods have been proposed in addition to the method of increasing or decreasing the grate speed so as to follow the set evaporation amount or the set temperature with reference to the evaporation amount or the furnace outlet temperature. ing.

For example, a combustion control method in a refuse incinerator having a configuration illustrated in FIG. 4 has been proposed. Specifically, drying stoker 110a · combustion stoker 110b, supplies the primary combustion air _{A 1} from below the stoker 110 consisting of post-combustion stoker 110c, furnace combustion stage gas G 'after that occurred on post-combustion stoker 110c A part of the exhaust gas G ″ is blown out as a recirculation gas into the downstream basin of the primary combustion chamber 112, and the combustion gas G generated on the dry stoker 110a and the combustion stoker 110b by the recirculation gas G ″. Are mixed to form a reduction zone 125 between the primary combustion chamber 112 and the secondary combustion chamber 113, and after being drawn out of the furnace, the combustion stage gas G ′ is used as a recirculation gas to form the secondary combustion chamber 113. with blown to the inner, by supplying the secondary combustion air a ₂ into the secondary combustion chamber 113 to completely burn the unburnt gas and unburnt secondary combustion chamber (For example, refer patent document 1). In the figure, 101 is a waste incinerator, 102 is a waste heat boiler, 103 is a superheater, 104 is an economizer, 105 is a degassing heater, 106 is a bag filter, 107 is an induction fan, 108 is a furnace body, 109 is Garbage supply hopper, 111 is a hopper under the stoker, 114 is an ash outlet, 115 is an exhaust gas outlet, 116 is a primary combustion air supply device, 117 is a recirculation gas passage, 118 is a recirculation gas blower, 119 is a recirculation gas passage, 120 is Reflux gas blower, 121 is a heat exchanger, 122 is a secondary combustion air supply line, 123 is a damper, 124 is an oxygen concentration detector, 125 is a reduction zone, 126 is a primary combustion air supply line, and 127 is a primary combustion air A blower is shown.

JP 2005-214513 A

However, there are some problems and requests in the conventional combustion control method.
(I) By measuring the exhaust gas temperature, the gas composition in the exhaust gas, and the like, the combustion control of the waste that controls the amount of combustion waste, the amount of combustion air, and the temperature of combustion air, the appropriate combustion control without time delay was difficult.
(Ii) Since the calorific value of waste plays an important role in combustion control, a method of sampling and analyzing waste has been proposed, but it takes a lot of time for sampling and analysis. Not suitable for control. For example, sampling may take several hours, and analysis may take several days.
(Iii) In the conventional method used for combustion control by estimating the combustion state based on the amount of boiler evaporation or cooling water used to cool the combustion gas in the incinerator, the correlation varies depending on the type and properties of the waste. In many cases, the generated heat generation error is not suitable for combustion control.
(Iv) The calorific value of waste has a correlation with the amount of water, and the calorific value can be roughly estimated by measuring the specific gravity of the waste, but the waste whose specific gravity is being measured is discarded at that time. In many cases, it is not suitable for combustion control due to large errors.
(V) A method of calculating waste color shading information is generally used as a method of estimating the amount of heat generated by waste. However, white waste is often paper-based, and black is often pruned. For this reason, it is often not suitable for combustion control due to lack of quantitativeness.

  Therefore, the present invention has been made in view of the above situation, and its purpose is to solve such problems and to obtain information related to the calorific value of the burning waste continuously in real time with high accuracy. An object of the present invention is to provide a method for controlling combustion of waste without time delay with respect to the current combustion state using this, and a combustion control apparatus to which the method is applied.

The waste combustion control method according to the present invention is characterized in that in a process of burning a predetermined amount of waste, combustion control of an incinerator is performed based on the following procedure.
(1) Calculate the calorific value of the waste from the measured component concentration in the combustion exhaust gas.
(2) The boiler evaporation amount is calculated based on the calculated waste heat generation amount.
(3) Based on the calculated amount of boiler evaporation, the amount of waste, combustion air, and auxiliary combustion material supplied to the incinerator is controlled.

In an incinerator with a waste heat boiler, the amount of combustion heat generated by waste combustion is proportional to the amount of boiler evaporation generated from the waste heat boiler that absorbs the amount of combustion exhaust gas heat, and automatic combustion control is performed using this boiler evaporation amount as a guideline. Has been built. In the verification process, the inventor further calculates the boiler evaporation amount based on the information indicating the current combustion state, not the actual boiler evaporation amount, and uses the calculated value for waste feed speed control and combustion air amount control. We obtained knowledge that more stable combustion control can be realized if applied. The present invention continuously obtains information related to the calorific value of burning waste in real time with high accuracy, and uses this to control the combustion of waste without time delay with respect to the current combustion state. Made possible.

The waste combustion control method according to the present invention is characterized in that the waste heat generation amount is calculated based on the following procedure.
(R1) The component concentrations of oxygen and moisture in the exhaust gas are measured.
(R2) From the measured oxygen and moisture component concentrations, the carbon dioxide concentration in the exhaust gas is calculated based on the following formula 1.
[CO ₂ ] = Ro × (100− [H ₂ O]) / 100− [O ₂ ] Formula 1
Here, the value in [] indicates the percentage display concentration, and Ro indicates a coefficient set by subtracting the amount of oxygen component taken into the ash from the oxygen concentration in the atmosphere.
(R3) The nitrogen concentration in the exhaust gas is calculated using the oxygen concentration, water concentration, and carbon dioxide concentration.
(R4) A conversion factor for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and the converted component concentrations of oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion factor.
(R5) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted component concentrations of oxygen, carbon dioxide and moisture.
(R6) From the calculated oxygen consumption amount, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the generated moisture amount and the waste contained in the waste Calculate the amount of latent heat from the total amount of moisture.
(R7) The amount of waste processed per unit supply amount of combustion air is calculated from the supply amount of waste treated by combustion.
(R8) An estimated calorific value A per treated waste amount is calculated from the calculated calorific value, latent heat amount and waste amount.
As described above, it is possible to control the combustion of waste without time delay by acquiring information indicating the current combustion state in real time and calculating the amount of combustion heat and the amount of boiler evaporation based on this information. It was. At this time, from the exhaust gas composition immediately after combustion acquired in real time, the carbon, hydrogen and moisture in the waste directly related to the calorific value of the waste as the fuel are obtained, and based on this, the oxygen consumption, combustion heat, The amount of latent heat and the amount of waste (processing amount) can be calculated. The inventor has found that in the verification process, the carbon dioxide (CO ₂ ) concentration in the exhaust gas can be calculated based on the oxygen (O ₂ ) concentration and the moisture (H ₂ O) concentration in the exhaust gas, By using the unit supply amount of combustion air as a calculation standard for oxygen consumption, etc., the oxygen consumption per unit supply amount of combustion air, the amount of combustion heat, the amount of latent heat, and the amount of waste treatment are accurately calculated. It was found that the calorific value ( estimated calorific value A) per amount of processed waste with a high amount of can be calculated . In other words, even if the waste has many variables such as properties, such variable elements are calculated by calculating from the calculated values per unit supply amount of the combustion air using the measured component concentration measurement values in the exhaust gas. Can be calculated . Therefore, it is possible to acquire information related to the calorific value of the burning waste continuously in real time and use it to control the combustion of waste without time delay with respect to the current combustion state. I made it.

The waste combustion control method according to the present invention is characterized in that the waste heat generation amount is calculated based on the following procedure.
(S1) The component concentrations of oxygen, carbon dioxide and moisture in the exhaust gas are measured.
(S2) The nitrogen concentration in the exhaust gas is calculated from the measured component concentrations.
(S3) A conversion factor for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and the converted component concentrations of the oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion factor.
(S4) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted component concentrations of oxygen, carbon dioxide and moisture.
(S5) From the calculated oxygen consumption amount, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the generated moisture amount and the waste contained in the waste Calculate the amount of latent heat from the total amount of moisture.
(S6) The amount of waste treated per unit supply amount of combustion air is calculated from the amount of waste treated after combustion.
(S7) From the calculated calorific value, latent heat quantity and waste quantity, an estimated calorific value B per treated waste quantity is calculated.
According to the above configuration, as the exhaust gas composition immediately after combustion, from the measured values of measured CO ₂ concentration, O ₂ concentration, and H ₂ O concentration, carbon in the waste directly related to the calorific value of the waste that becomes the fuel, Hydrogen and moisture are obtained, and based on this, oxygen consumption, combustion heat, latent heat, and waste (treatment amount) can be calculated. In addition, by using the unit supply amount of combustion air as the calculation standard at this time, the oxygen consumption per unit supply amount of combustion air, the amount of combustion heat, the amount of latent heat, the amount of waste treatment are calculated, and the treated waste The calorific value per quantity ( estimated calorific value B) can be calculated. In other words, even if the waste has many variables such as properties, such variable elements are calculated by calculating from the calculated values per unit supply amount of the combustion air using the measured component concentration measurement values in the exhaust gas. Can be calculated . Therefore, it is possible to acquire information related to the calorific value of the burning waste continuously in real time and use it to control the combustion of waste without time delay with respect to the current combustion state. I made it.

The waste combustion control method according to the present invention is characterized in that the waste heat generation amount is calculated based on the following procedure.
(T1) The oxygen and moisture component concentrations in the exhaust gas are measured.
(T2) The actual excess air ratio is calculated from the measured oxygen component concentration.
(T3) By applying the actually measured moisture amount and the actually measured air excess rate to the correlation between the preset excess air rate and the calorific value of the waste using the moisture content in the combustion gas as an index, the estimated calorific value B Is calculated.
As described above, the amount of heat generated from waste has a correlation with the amount of moisture in the combustion gas, but is greatly affected by the supply amount of combustion air, that is, the excess air ratio. The present invention calculates the excess air ratio, which is a large variation factor in the calorific value measurement of such waste, by measuring the oxygen component concentration in the exhaust gas as an actual measurement value, and using a preset excess air ratio as an index. The calorific value can be calculated from the correlation with the moisture content in the combustion gas (estimated calorific value C). In other words, even if the waste has many variables such as properties, the calorific value that reflects these variables is calculated by calculating the excess air ratio of the combustion air using measured component concentration measurements in the exhaust gas. Can be calculated . Therefore, it is possible to acquire information related to the calorific value of the burning waste continuously in real time and use it to control the combustion of waste without time delay with respect to the current combustion state. I made it.

The present invention is a combustion control apparatus to which the above-described waste combustion control method is applied, and includes at least components of waste supply amount measurement unit, combustion air supply amount measurement unit, and oxygen, carbon dioxide and moisture in exhaust gas A concentration measuring unit is provided, and the amount of waste, combustion air, and auxiliary material supplied to the incinerator is controlled using any one of the calculated waste calorific value or estimated calorific values A to C. It is characterized by.
With this configuration, information related to the calorific value of the burning waste can be acquired continuously in real time with high accuracy, and this can be used to control the combustion of waste without a time delay relative to the current combustion state. Became possible.
Further, the present invention is characterized in that, in a process of burning a predetermined amount of waste, the combustion control of the incinerator is performed based on the following procedure using the heat generation amount of the waste calculated by the above calculation method. .
(1) The estimated calorific value A or the estimated calorific value B is calculated.
(2) A boiler evaporation amount is calculated based on the calculated calorific value A or B.
(3) Based on the calculated amount of boiler evaporation, the amount of waste, combustion air, and auxiliary combustion material supplied to the incinerator is controlled.
The present invention also relates to a combustion control apparatus that uses a calorific value of waste calculated by the above-described calculation method in a process for burning a predetermined amount of waste, and includes at least a waste supply amount measuring unit, Combustion air supply amount measurement unit and oxygen and moisture in exhaust gas, or component concentration measurement unit of oxygen, moisture and carbon dioxide concentration, incineration using the calculated calorific value A or calorific value B It is characterized by controlling the amount of waste, combustion air, and auxiliary material supplied to the furnace.

Schematic illustrating the basic implementation procedure of the combustion control method according to the present invention Schematic showing a basic configuration example of a combustion control device according to the present invention Schematic illustrating the comparison between the actual measured value and the calculated value of boiler evaporation Schematic illustrating a stoker-type waste incinerator according to a conventional combustion control method

<Waste Combustion Control Method According to the Present Invention>
A waste combustion control method according to the present invention (hereinafter sometimes referred to as “the present method”) is characterized in that, in a process of burning a predetermined amount of waste, combustion control of an incinerator is performed based on the following procedure. And Information relating to the calorific value of the burning waste can be obtained continuously and accurately in real time, and the combustion control of the waste without time delay can be performed using this information.
(1) Calculate the calorific value of the waste from the measured component concentration in the combustion exhaust gas.
(2) The boiler evaporation amount is calculated based on the calculated waste heat generation amount.
(3) Based on the calculated amount of boiler evaporation, the amount of waste, combustion air, and auxiliary combustion material supplied to the incinerator is controlled.
Embodiments of a waste combustion control method and a combustion control apparatus according to the present invention will be described below in detail with reference to the drawings.

(1) to calculate the heating value of the waste from the component concentration measured calculation combustion exhaust gas waste heat value. Specifically, for example, it is calculated by using any one of the following three methods (estimated calorific values A to C). Or 2 or 3 of estimated calorific value A-C can be contrasted, and the optimal estimated calorific value can be set up. The set value can be set in consideration of the characteristics of the waste specified in advance or the combustion characteristics of the incinerator. By setting one of the respective estimated calorific value as the optimum estimated calorific value, or by calculating the simple average value or weighted average value of each estimated calorific value, calculated more calorific accurate waste W can do.
(R) Estimated calorific value A: As will be described later (R1) to (R8), the carbon dioxide concentration is calculated based on the measured oxygen and moisture component concentrations, and these are used as the reference nitrogen concentration. And the calorific value, latent heat amount and waste amount of each component are calculated from the oxygen, carbon dioxide and moisture component concentrations converted based on the nitrogen concentration, and are calculated from the calculated values.
(S) Estimated calorific value B: As described later (S1) to (S7), the nitrogen concentration is calculated based on the measured component concentrations of oxygen, moisture, and carbon dioxide, and converted based on the nitrogen concentration. The calorific value, latent heat amount and waste amount of each component are calculated from the component concentrations of oxygen, carbon dioxide and water, and are calculated from the calculated values.
(T) estimated calorific value C: calculated based manner, calculates the actual air excess ratio from the measured oxygen concentration, the actually measured moisture concentration and said actual measured excess air ratio which will be described later (T1) ~ (T3) Is done.

(2) Calculation of boiler evaporation amount Based on the waste heat generation amount calculated in (1) above, the boiler evaporation amount is calculated . Specifically, the boiler evaporation amount can be obtained from the calculated waste heat generation amount based on the relationship between the waste heat generation amount and the boiler evaporation amount as shown in the following equations 2 and 3.
(Waste combustion heat amount) = (Waste heat value) x (Waste input amount)
= (Boiler evaporation x Steam enthalpy + Heat output-Heat input) Equation 2
(Boiler evaporation) = (Waste combustion heat-Bring heat + Bring heat) / (Steam enthalpy)
Here, the waste input amount, steam enthalpy, carry-out heat amount, and carry-in heat amount can be calculated in real time according to each measured value in this process.

(3) Control of the amount of waste, combustion air and auxiliary materials supplied
Based on the calculated amount of boiler evaporation, the amount of waste, combustion air, and auxiliary combustion material supplied to the incinerator is controlled. Specifically, as illustrated in FIG. 1, for example, the supply amount of waste, fuel air, and auxiliary combustion material is feedback-controlled based on the calculated boiler evaporation amount, and other elements (for example, a combustion furnace) By being corrected by the internal temperature or the like, it is possible to control the combustion of waste without time delay with respect to the combustion state in real time.

[Calculation method of waste heat value]
The waste heat generation amount is calculated based on the estimated heat generation amounts A to C and combinations thereof as described above. Hereinafter, a calculation method procedure for each estimated heat generation amount will be described in detail.

(R) Calculation of estimated calorific value A (R1) The component concentrations of oxygen and moisture in the exhaust gas are measured.
Obtaining combustion state information in real time by measuring oxygen and moisture component concentrations in combustion exhaust gas with an O ₂ concentration meter and H ₂ O concentration meter installed in the incinerator or at the furnace outlet Can do.

(R2) The concentration of carbon dioxide in the exhaust gas is calculated from the measured oxygen and moisture component concentrations based on the following formula 1.
[CO ₂ ] = Ro × (100− [H ₂ O]) / 100− [O ₂ ] Formula 1
Here, [] indicates the percentage display concentration, and Ro indicates a coefficient set by subtracting the oxygen component amount taken into the ash from the oxygen concentration in the atmosphere.
That is, in the case where the waste is completely burned and the oxygen and nitrogen in the waste do not affect the oxygen and nitrogen component concentrations in the exhaust gas, the carbon dioxide concentration [CO ₂ ] and the oxygen concentration [ O ₂ ] has the following relationships 4 to 7 (d: dry state, w: wet state).
[CO ₂ (d)] + [O ₂ (d)] = 21 Formula 4
[CO ₂ (d)] = [CO ₂ (w)] × 100 / (100− [H ₂ O]) Equation 5
[O ₂ (d)] = [O ₂ (w)] × 100 / (100− [H ₂ O]) Equation 6
[CO ₂ (w)] = 21 × (100− [H ₂ O]) / 100− [O ₂ (w)] Equation 7
However, in the actual operation state, “21” in Expression 7 does not hold, and it has been proved to be, for example, “19: Ro”. It is understood that the amount of oxygen component taken into the ash generated by the combustion reaction is the difference. [CO ₂ (d)] and [O ₂ (d)] can be set in advance by performing analysis / measurement such as manual analysis during actual operation.

(R3) The nitrogen concentration in the exhaust gas is calculated using the oxygen concentration, moisture concentration, and carbon dioxide concentration.
Specifically, based on the following equation 8, the nitrogen (N ₂ ) concentration in the exhaust gas is calculated from the actually measured oxygen concentration, water concentration, and calculated carbon dioxide concentration.
[N ₂ (w)] = 100 − ([O ₂ (w)] + [CO ₂ (w)] + [H ₂ O])

(R4) A conversion coefficient for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and converted component concentrations of oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion coefficient.
(R4-1) Calculation of Conversion Factor for Nitrogen Concentration in Combustion Air Based on nitrogen, which is an invariable factor before and after the combustion reaction, this is divided into the partial pressure (reference nitrogen concentration Tn: combustion air as 100 when supplying combustion air) Then, a coefficient (conversion coefficient) t to be converted into 79) is calculated based on the following formula 9.
t = Tn (= 79) / [N ₂ (w)] Equation 9
(R4-2) Calculation of converted component concentrations of oxygen, carbon dioxide, and moisture Calculate converted component concentrations of oxygen, carbon dioxide, and moisture by multiplying each component concentration of oxygen, carbon dioxide, and moisture by a conversion factor t. Based on the following formula 10, the converted oxygen concentration Tx, the converted carbon dioxide concentration Td, and the converted water concentration Tw are calculated. At this time, each numerical value is the amount of oxygen, the amount of carbon dioxide and the amount of water per unit supply amount of combustion air.
Tx = [O ₂ (w)] × t, Td = [CO ₂ (w)] × t, Tw = [H ₂ O] × t
... Formula 10

(R5) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted component concentrations of oxygen, carbon dioxide and moisture.
Based on the oxygen concentration (reference oxygen concentration) To in the combustion air, the oxygen consumption amount Do per unit supply amount of the combustion air used for the combustion process is calculated from the converted oxygen concentration Tx converted based on the following formula 11. calculate.
Do = To−Tx Equation 11
Here, To = (100−Tn), and can be replaced with 21 [%].

(R6) From the calculated oxygen consumption amount, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the generated moisture amount and the waste contained in the waste Calculate the amount of latent heat from the total amount of moisture.
(R6-1) Carbon dioxide per unit supply amount of combustion air and calorific value related to moisture calculated from the calculated oxygen consumption amount Do to carbon dioxide generated in the combustion process per unit supply amount of combustion air The calorific value Hd and the calorific value Hw related to moisture are calculated. That is, the total amount of oxygen required for complete combustion of the carbon component and hydrogen component in the waste W becomes the oxygen consumption amount Do, and the amount of oxygen consumed by the carbon component is the same as the converted carbon dioxide concentration Td from the following reaction formula 1. And the remaining amount is the amount of oxygen consumed by the hydrogen component (lower reaction formula 2). That is, Hc and Hh in the reaction formulas 1 and 2 indicate reaction heat (calorific value) by each reaction.
C + O ₂ → CO ₂ + Hc: Reaction formula 1
4H + O ₂ → 2H ₂ O + Hh (Scheme 2)
Therefore, the heat generation amounts Hd and Hw can be calculated by the following equations 12 and 13 based on the heat generation amounts Hc and Hh.
Hd = Hc × Td Equation 12
Hw = Hh × (Do−Td) Equation 13
(R6-2) Calculation of latent heat amount from total amount of moisture Based on latent heat Lo of water, latent heat amount of total amount Tw of combustion generated moisture amount and moisture amount contained in waste based on the following formula 14. Lw is calculated.
Lw = Lo × Tw Equation 14

(R7) The amount of waste processed per unit supply amount of combustion air is calculated from the supply amount of waste treated by combustion.
From the supply amount Wi of the burned waste W and the supply amount Ai of the combustion air at that time, the processed waste amount (converted waste amount) Wo per unit supply amount of the combustion air is calculated based on the following equation 15. To do.
Wo = Wi / Ai Equation 15

(R8) An estimated calorific value A per treated waste amount is calculated from the calculated calorific value, latent heat amount and waste amount.
Based on the calculated calorific value (Hd + Hw), latent heat amount Lw, and waste amount Wo, an estimated calorific value A per treated waste amount is calculated based on the following equation 16.
A = (Hd + Hw−Lw) / Wo Equation 16
At this time, the calculated estimated calorific value A is a numerical value per unit supply amount of the combustion air, and the estimated calorific value A per unit supply amount of the waste W is obtained by using the actually measured supply amount of combustion air. Can be converted. It can be set as a highly objective evaluation value for the quality (characteristics) of the waste W.

(S) Calculation of estimated calorific value B (S1) The component concentrations of oxygen, carbon dioxide and moisture in the exhaust gas are measured.
Combustion by measuring the component concentrations of oxygen, moisture and carbon dioxide in the flue gas with an O ₂ concentration meter, H ₂ O concentration meter and CO ₂ concentration meter provided in the furnace or at the furnace outlet Status information can be obtained in real time.

The following procedures (S2) to (S7) can be performed in the same manner as the above procedures (R3) to (R8). Abbreviated here.
(S2) The nitrogen concentration in the exhaust gas is calculated from the measured component concentrations.
(S3) A conversion coefficient for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and converted component concentrations of oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion coefficient.
(S4) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted oxygen, carbon dioxide and moisture component concentrations.
(S5) From the calculated oxygen consumption, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the amount of generated moisture and the amount of moisture contained in the waste The amount of latent heat is calculated from the total amount.
(S6) The amount of waste treated per unit supply amount of combustion air is calculated from the amount of waste treated after combustion.
(S7) From the calculated calorific value, latent heat quantity and waste quantity, an estimated calorific value B per treated waste quantity is calculated.

(T) Calculation of estimated calorific value C (T1) Measurement of oxygen and moisture component concentrations in exhaust gas The same procedure as in the above procedure (R1) can be performed. Abbreviated here.

(T2) Calculation of Actual Air Excess Ratio The actual air excess ratio λo is calculated from the measured oxygen concentration based on the following equation 17.
λo = To (= 21) / (To− [O ₂ ]) Equation 17

(T3) Calculation of Estimated Calorific Value C Measured moisture concentration [Correlation between the preset excess air ratio λ and the calorific value of waste with the moisture content (concentration) in the combustion gas (exhaust gas) as an index [ H ₂ O] and the measured excess air ratio λo are applied to calculate the estimated calorific value C. Specifically, a reference waste is set in advance, and a correlation diagram between the moisture concentration and the estimated calorific value C using the measured excess air ratio as an index is prepared. The measured moisture concentration [H ₂ O] and measured By applying the excess air ratio λo, the estimated calorific value C can be obtained. By preparing a plurality of correlation diagrams according to the properties (quality) of the waste as a reference, it is possible to calculate the estimated calorific value C with higher accuracy. Also, instead of the correlation diagram, a correlation function of moisture concentration-estimated calorific value C using the measured excess air ratio as an index is prepared, and the measured moisture concentration [H ₂ O] and the measured excess air ratio λo are applied. Thus, the estimated calorific value C can be calculated.

<Combustion control device according to the present invention>
The combustion control device according to the present invention (hereinafter sometimes referred to as “the present device”) includes at least a waste supply amount measurement unit, a combustion air supply amount measurement unit, and oxygen, carbon dioxide, and moisture component concentrations in exhaust gas. Having a measuring section and controlling the supply amount of waste, combustion air, and auxiliary combustion material to be put into the incinerator by using any one of the calculated calorific value or estimated calorific value A to C Features. Specifically, for example, a waste supply amount measurement unit and a combustion air supply amount measurement unit provided in a waste treatment apparatus including an incinerator illustrated in FIG. 2 (hereinafter also referred to as “the present treatment apparatus”). And a component concentration measuring unit.

In this processing apparatus, the storage pit 1 in which the waste W is stored, the hopper 2 in which the waste W in the storage pit 1 is input by the transfer means 1a (for example, a crane), and the waste input in the hopper 2 A stalker 3 to which W is fed by the waste supply device 4 is provided. The stalker 3 is driven to reciprocate to feed the waste W to the furnace body 10. The furnace body 10 includes a primary combustion zone 10A provided at the top of the stoker 3, and a primary combustion air supply device 5 for supplying primary combustion air to the secondary combustion zone 10B, the stoker 3 and the primary combustion zone 10A. A secondary combustion air supply device 6 for supplying secondary combustion air to the secondary combustion zone 10B, an ash discharge part 7 for discharging dust ash D, and an exhaust gas discharge part 8 for discharging exhaust gas E in the furnace are provided.
The waste W sent to the stalker 3 is dried by the high-temperature combustion gas generated by the combustion in the primary combustion zone 10A, partially combusted by the primary combustion air, and further completely combusted. The gas generated by the combustion includes water (H ₂ O, including water vapor generated by evaporation of water contained in the waste W), hydrocarbon gas (HC) generated by dry distillation, carbon monoxide generated by incomplete combustion ( CO) and carbon dioxide (CO ₂ ) by complete combustion. In the secondary combustion zone 10B, the unburned material or incomplete combustion product in the primary combustion zone 10A is completely burned by the secondary combustion air supplied to the lower, middle and upper parts thereof. The dust ash D generated by the combustion is discharged from the ash discharge unit 7, and the exhaust gas E in the furnace is discharged from the exhaust gas discharge unit 8. In addition, nitrogen oxides (NOx) generated in combustion under high temperature conditions, chlorine compounds and sulfur oxides (SOx) originating from chlorine, sulfur, etc. contained in the waste W are in trace amounts, and the calorific value I will not touch here directly because it has little impact.

(A) Waste Supply Amount Measurement Unit A waste input weight detection sensor 12 and a laser distance meter 13 are provided as sensor units for measuring the amount and quality of the waste W input into the hopper 2. The distance to the surface of the waste W is measured by the laser distance meter 13, and the volume of the waste W to be input is measured. The waste input weight detection sensor 12 measures the weight of the waste W. By detecting the volume and weight of the waste W, a change in the specific gravity of the waste W can be detected at predetermined time intervals. As described above, if the specific gravity of the waste W is known, the quality (water content, etc.) of the waste W can be predicted.

(B) Combustion air supply amount measuring unit Primary combustion air supply device for combusting air is formed in the primary combustion zone 10A so as to form an optimal combustion state of the waste W placed and transferred on the stalker 3 5 to be supplied in multiple stages. For example, the supply amount of each combustion air is controlled while monitoring the amount (volume) of the waste W, the surface temperature, the flow rate of the combustion gas, and the like in the order of the drying step, the combustion step, and the post-combustion step. . Further, in the secondary combustion zone 10B, a plurality of secondary combustion air supply devices 6 are used to cool or dilute the exhaust gas E together with complete combustion of the unburned or incompletely burned components in the primary combustion zone 10A. It is supplied in stages. For example, the supply amount of each combustion air is controlled from the upper part and lower part (further the middle part) of the secondary combustion zone 10B while monitoring the component concentration (details will be described later), the temperature, the flow rate of the exhaust gas E, etc. The Here, the supply amount of combustion air means the total flow rate measured by a flow meter (not shown) provided in each stage of the primary combustion air supply device 5 and the secondary combustion air supply device 6. . For example, a flow meter with a flow control function can be used as the flow meter. Further, in the configuration example of the present processing apparatus, the gas flow velocity meter 17 is provided as a sensor unit related to the gas flow direction in the primary combustion zone 10A, and the infrared radiation thermometer 18 is used as a sensor unit that detects process data related to the temperature distribution. And a steam flow meter 19 for measuring the steam flow rate is provided at the end of the furnace body 10 as a sensor for measuring the amount of evaporation corresponding to the energy accompanying combustion.

(C) Component concentration measuring unit in exhaust gas In the furnace body 10, a sensor unit for detecting the combustion state of the waste W and the combustion result is provided. Specifically, an O ₂ concentration meter 14, a CO ₂ concentration meter 15, and an H ₂ O concentration meter 16 are provided in at least one of the secondary combustion zone 10B and the primary combustion zone 10A (in FIG. 2, secondary combustion). An example in which the CO ₂ concentration meter 15 is provided only in the zone 10B is shown, but it is not limited to this as described above). Here, as the O ₂ concentration meter 14, the CO ₂ concentration meter 15, and the H ₂ O concentration meter 16, a laser light source (not shown) scans the wavelength and emits a laser beam having a constant intensity in the furnace body 10. It is preferable to employ a method of detecting the component concentration and temperature of the gas by irradiating the gas and measuring the remaining laser light with a laser receiver. This is preferable in that exhaust gas to be measured can be detected in a non-contact manner and detection information at the same site can be obtained at the same time. Moreover, you may use the well-known sensor which detects the component density | concentration of each gas. The composition of the burned waste W can be calculated from the concentration of each component in the exhaust gas, and the calorific value of the waste W can be calculated from the relationship with the supply amount of combustion air. Hereinafter, for each component concentration, the oxygen component concentration may be referred to as oxygen concentration, the nitrogen component concentration may be referred to as nitrogen concentration, and the like.

<Demonstration experiment of this method>
Using the estimated calorific value A, the combustion control function of the method and its technical effect were verified for the treatment apparatus supplied with waste.
〔inspection result〕
(I) 3 (A) is, the processing apparatus when the continuous operation of 12 hours, measured values of boiler evaporation amount and the oxygen concentration and the water concentration in the exhaust gas at that time by using the estimated calorific value A shows the calculated value of the calculated boiler evaporation amount.
(Ii) FIG. 3B is an enlarged view of a part thereof. It can be seen that the calculated value of the boiler evaporation amount precedes the actual measurement value of the boiler evaporation amount. The difference was about 240 seconds.
(Iii) FIG. 3C shows the correlation between the two. Results with very good correlation were obtained.

As described above, the following excellent technical effects can be obtained by the waste combustion control method according to the present invention and the combustion control device to which the waste combustion control method is applied.
(I) Optimal combustion control can be realized by continuously measuring the calorific value of waste without delay.
(Ii) In a facility with power generation facilities, power generation efficiency can be improved by stabilizing the evaporation amount and minimizing the amount of exhaust gas by calculating the estimated amount of boiler evaporation before the actual measurement (about 240 seconds in the demonstration experiment). Can be improved.
(Iii) Since the calorific value of the currently burning waste is known, it is possible to cope with a transient response such as abnormal combustion with automatic operation.
(Iv) Since the existing automatic combustion control does not require a significant change, it can be easily applied to existing facilities at a low cost and has a wide range of applications.
(V) Since it becomes easier to operate the waste treatment facility, it is not necessary to depend on the qualities of the operators, and it is possible to save labor by reducing the number of personnel.

Claims (3)

In the process of burning a predetermined amount of waste, the amount of boiler evaporation is calculated based on the calorific value of the waste calculated based on the following procedure, and the waste is put into the incinerator based on the amount of boiler evaporation , A waste combustion control method characterized by controlling the supply amount of combustion air and auxiliary combustion material to control combustion of an incinerator.
(R1) The component concentrations of oxygen and moisture in the exhaust gas are measured.
(R2) From the measured oxygen and moisture component concentrations, the carbon dioxide concentration in the exhaust gas is estimated based on the following formula 1.
[CO ₂ ] = Ro × (100− [H ₂ O]) / 100− [O ₂ ] Formula 1
Here, the value in [] indicates the percentage display concentration, and Ro indicates a coefficient set by subtracting the amount of oxygen component taken into the ash from the oxygen concentration in the atmosphere.
(R3) The nitrogen concentration in the exhaust gas is calculated using the oxygen concentration, water concentration, and carbon dioxide concentration.
(R4) A conversion factor for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and the converted component concentrations of oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion factor.
(R5) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted component concentrations of oxygen, carbon dioxide and moisture.
(R6) From the calculated oxygen consumption amount, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the generated moisture amount and the waste contained in the waste Calculate the amount of latent heat from the total amount of moisture.
(R7) The amount of waste processed per unit supply amount of combustion air is calculated from the supply amount of waste treated by combustion.
(R8) An estimated calorific value A per treated waste amount is calculated from the calculated calorific value, latent heat amount and waste amount. In the process of burning a predetermined amount of waste, the amount of boiler evaporation is calculated based on the calorific value of the waste calculated based on the following procedure, and the waste is put into the incinerator based on the amount of boiler evaporation , A waste combustion control method characterized by controlling the supply amount of combustion air and auxiliary combustion material to control combustion of an incinerator.
(S1) The component concentrations of oxygen, carbon dioxide and moisture in the exhaust gas are measured.
(S2) The nitrogen concentration in the exhaust gas is calculated from the measured component concentrations.
(S3) A conversion factor for the nitrogen concentration in the combustion air is calculated based on the calculated nitrogen concentration, and the converted component concentrations of the oxygen, carbon dioxide, and moisture are calculated by multiplying the conversion factor.
(S4) The oxygen consumption per unit supply amount of the combustion air used for the combustion process is calculated from the converted component concentrations of oxygen, carbon dioxide and moisture.
(S5) From the calculated oxygen consumption amount, the calorific value related to carbon dioxide and moisture generated in the combustion process per unit supply amount of combustion air, the generated moisture amount and the waste contained in the waste Calculate the amount of latent heat from the total amount of moisture.
(S6) The amount of waste treated per unit supply amount of combustion air is calculated from the amount of waste treated after combustion.
(S7) From the calculated calorific value, latent heat quantity and waste quantity, an estimated calorific value B per treated waste quantity is calculated. A combustion control apparatus to which the waste combustion control method according to claim 1 or 2 is applied, wherein at least the supply amount measurement unit of waste, the supply amount measurement unit of combustion air, and oxygen and moisture in exhaust gas , or Supply amount of waste, combustion air, and auxiliary combustible materials to be put into the incinerator using the calculated calorific value A or the calorific value B calculated as described above. The combustion control device characterized by controlling.