JPH06265124A - Method for controlling combustion of dust in dust incinerator - Google Patents

Abstract

PURPOSE:To perform an automatic dust combustion control by a method wherein an amount of air blown into a dust incinerator is controlled in such a manner that the most suitable concentration of oxygen for combustion set in response to quality of dust may be attained and further a dust moving speed on a grid is controlled in response to a gasification speed. CONSTITUTION:Dust quality specified by dust calorie and amount of raw gas water vapor of dust fed into an incinerator 1 is obtained and then an amount of air blown into the incinerator 1 is controlled in such a manner that a concentration of oxygen most suitable for dust combustion may be attained in response to the dust quality. Gasification speed of fed dust is calculated and then a dust moving speed on a grid 2 is controlled in response to the calculated gasification speed. With such an arrangement as above, dust combustion in the dust incinerator and the dust moving speed on the grid are controlled automatically and properly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the combustion of refuse in a refuse incinerator.

[0002]

2. Description of the Related Art When incinerating various kinds of waste such as paper, fiber, plastic, wood, kitchen waste, etc. in a waste incinerator, appropriate combustion according to the type and amount of the waste put in the incinerator It is necessary to control. Figure 5
It is a schematic explanatory drawing which shows an example of the conventional combustion control method. As shown in FIG. 5, a grate 2 composed of a dry grate 2a, a combustion grate 2b, and a post-combustion grate 2c is provided in the incinerator 1, and the grate 2 is loaded into the furnace from the throat 1a. The dust is sequentially moved through the dry grate 2a, the combustion grate 2b, and the post-combustion grate 2c, and is burned in the meantime.

An air supply pipe 6 is attached to the lower air supply port 1b of the incinerator 1, and the air supply pipe 6 is provided with a blower 3 for sending air into the furnace. A damper 4 is provided on the air supply pipe 6 on the inlet side, and the amount of blown air is controlled by the damper 4. The incineration ash is discharged to the outside of the furnace through the discharge port 5, and the combustion exhaust gas is cooled by the cooling water injected from the nozzle 8 in the gas cooling chamber 7 connected to the gas discharge port 1c at the upper part of the incinerator 1. Moreover, it is discharged through the flue 9.

A branch pipe 26 reaching the upper part of the incinerator 1 is connected to the air supply pipe 6, and a damper is provided in the middle of the branch pipe 26.
27 are provided. A part of the cooling air from the air supply pipe 6 is blown into the upper part of the incinerator 1 through the branch pipe 26, thereby preventing the combustion exhaust gas discharged from the inside of the furnace from becoming too hot. There is.

The temperature of the exhaust gas is measured by the gas thermometer 10 provided at the gas outlet 1c of the incinerator 1, and the measured temperature (θ ₁ ) of the exhaust gas is set by the exhaust gas temperature setter 29 (θ _r ), The damper 27 provided in the middle of the branch pipe 26 is operated by the furnace outlet gas temperature PID controller 23 and the damper driver 28. This controls the amount of cooling air supplied through the branch pipe 26 into the upper part of the incinerator.

A worker monitors the amount of dust accumulated in the incinerator 1 and the strength of the fire by an in-furnace television or the like, and a fire consisting of a dry grate 2a, a combustion grate 2b and a post-combustion grate 2c. The moving speed of each dust on the grid 2 is set by the setter 25.

In order to efficiently burn the waste in the incinerator 1 described above, when the amount of the waste deposited in the incinerator 1 is large, the combustion of the waste is promoted, while in the incinerator 1 If the amount of waste deposited in the furnace is low, it is necessary to slow down the combustion of the waste so that the new waste that is loaded into the furnace remains hot and can preheat the new waste.

[0008]

The conventional dust combustion control methods have the following problems. (1) As shown in FIG. 5, the air blown into the upper part of the incinerator 1 through the branch pipe 26 is mixed with the hot exhaust gas near the exhaust port 1c, and the exhaust gas becomes too hot. It does not contribute to the burning of waste. (2) When the amount of waste loaded in the incinerator 1 is small or the amount of heat generated by the waste is low, the amount of air blown by the blower 3 even if the damper 27 provided on the branch pipe 26 is closed. Is too large, it is difficult to maintain the inside of the incinerator 1 at an appropriate high temperature.

(3) The moving speed of dust on the grate 2 consisting of the dry grate 2a, the combustion grate 2b, and the post-combustion grate 2c depends on the amount of dust accumulated in the incinerator 1 The strength and the like are monitored, and the control is performed based on the amount of dust accumulated and the strength of the fire. Therefore, a worker for the above-mentioned control is required, and it is difficult to control an appropriate dust moving speed for each grate.

Therefore, an object of the present invention is to solve the above-mentioned problems and to automatically and appropriately perform the combustion of waste in a waste incinerator according to the amount of waste deposited in the incinerator, the quality of the waste, and the like. It is to provide a combustion control method that can be controlled.

[0011]

The inventor of the present invention has
We have conducted intensive research to develop a method that can automatically and appropriately control the combustion of waste in a waste incinerator according to the amount of waste accumulated in the incinerator, the quality of the waste, and the like. As a result, the following findings were obtained. If the cooling air is not blown into the upper portion of the conventional incinerator but the increased amount of air is blown from below the grate, the combustion speed can be improved and the temperature rise of the combustion exhaust gas can be suppressed. Then, based on the quality of the waste that is put into the waste incinerator, which is specified by the calorie and the amount of raw water vapor, the optimum oxygen concentration for combustion of the waste is set so that the set oxygen concentration is reached. To control the amount of air blown into the waste incinerator, while
If the gasification rate of the injected dust is obtained and the moving speed of the dust on the grate is controlled based on the obtained gasification rate, the combustion of the dust can be automatically and accurately controlled. .

The present invention has been made on the basis of the above-mentioned findings, and the method of the present invention is applied to a refuse incinerator for determining the rate of inputting refuse, the exhaust gas temperature at the furnace outlet, the exhaust gas (dry gas) oxygen concentration and the exhaust gas flow rate. Based on the obtained waste quality, based on the obtained waste quality, the optimum oxygen concentration for combustion of the waste is set, and the set waste is set. The amount of air blown into the refuse incinerator is controlled so that the oxygen concentration is reached, while the waste quality, the furnace outlet exhaust gas temperature, the exhaust gas (dry gas) oxygen concentration, and the exhaust gas flow rate, Calculate the gasification rate of the input waste,
It is characterized in that the moving speed of dust on the grate is controlled based on the obtained gasification speed.

[0013]

In the method of the present invention, the quality of waste is calculated by the amount of heat generated per unit weight of waste and the amount of water vapor contained in the produced gas per unit weight of waste. Therefore,
The quality of refuse in the furnace can be evaluated objectively and quantitatively. Then, such waste quality was evaluated in real time every moment, and the furnace outlet gas temperature, combustion air amount, etc. were controlled to values commensurate with the current waste quality, which was intended when designing the waste incinerator. An optimum combustion state can be realized. Furthermore, the disappearance rate of dust on the grate can be objectively and quantitatively evaluated by calculating it as the gasification rate of solid waste, which allows
The grate speed can be set automatically.

In the following, combustion of waste in the incinerator will be described.
The means for controlling the amount of combustion air and the grate velocity for efficient and stable operation will be described. To control the amount of combustion air, it is necessary to calculate the dust quality and oxygen concentration, and to control the grate velocity, it is necessary to calculate the refuse incineration rate. FIG. 2 is an explanatory diagram of the process variables in the refuse incinerator for calculating such waste quality, oxygen concentration and waste incineration rate.

Referring to FIG. 2, the process variables used in the present invention are shown below. In addition, the capital letters of the following U to E indicate the total amount value with respect to the total amount G of waste input, and the lower case letters in parentheses indicate the variable value per unit weight (1 kg) of the total amount of waste input. G: Waste speed Kg / Hr G _s : Waste input speed Kg / Hr G _f : Waste gasification speed Kg / Hr U (u): Waste calorie Kcal (Kcal / Kg) D (d): Dry gas generation amount Nm ^{3 / Hr (Nm 3 /Hr.Kg)} A b (a b): theoretical amount of combustion air ^{Nm 3 / Hr (Nm 3 /Hr.Kg} ) M (m): raw gas steam amount Nm ³ / Hr (Nm ³ _{/Hr.Kg) A t (a t)} : taking air quantity ^{Nm 3 / Hr (Nm 3 /Hr.Kg} ) A r (a r): excess air amount ^{Nm 3 / Hr (Nm 3 /Hr.Kg} ) J (j): raw gas flow rate ^{Nm 3 / Hr (Nm 3 /Hr.Kg} ) W (w): injection water Kg / Hr (Kg / Hr.Kg) E (e): exhaust gas flow rate Nm ³ / Hr (Nm ^{3 /} Hr.Kg)

F: Exhaust gas flow rate m / hr θ ₁ : Furnace outlet exhaust gas temperature ℃ θ ₂ : Gas cooler outlet gas temperature ℃ O ₁ : Raw gas oxygen concentration (dry gas) O ₂ : Exhaust gas oxygen concentration (dry gas) _id θ : dry gas theta ° C. enthalpy Kcal / Nm ³ i _m θ: steam theta ° C. enthalpy Kcal / Nm ³ i _a θ: air theta ° C. enthalpy Kcal / Nm ³

The process variable relational expressions are shown below. _{d = αu + d o a b} = βu + a o a r = a t -a b i d θ = C d θ i m θ = C m θ + b i a θ = C a θ J = Gj = E-1.24W = G (e-1.24w)

The constants are shown below. alpha: waste calorie dry gas generation factor ^{0.8 × 10 -3 Nm 3 / Kcal} d o: dry gas production basis weight 0.9Nm ³ / Kg β: theoretical consumption air amount coefficient ^{0.8 × 10 -3 Nm 3 / Kcal} a o: Theory consumption air basal rate 0.8Nm / Kg C _d: drying gas isobaric specific heat _{^{0.33Kcal / Nm 3 ℃ C m:}} . steam pressure specific heat _{^{0.36Kcal / Nm 3 ℃ C a:}} .. air isobaric specific heat 0.31Kcal / Nm ³ ℃ q: Heat of vaporization of water 432Kcal / Nm ³ σ: Exhaust gas flue cross-sectional area m ²

(1) Waste quality and oxygen concentration calculation and combustion air amount control Waste input speed (G _s ), water injection amount (w), furnace outlet exhaust gas temperature (θ ₁ ), gas cooler outlet gas temperature (θ) shown in FIG. ₂ ) and the exhaust gas oxygen concentration (O ₂ ), the quality of the waste loaded in the incinerator 1, that is, the waste calorie u (the calorific value per unit weight of the waste) and the steam amount m of the raw gas m ( The amount of water vapor contained in the generated gas per unit weight of waste) can be calculated.

When the target values of the refuse quality (u, m) and the furnace outlet gas temperature (θ ₁ ) are set,
The exhaust gas oxygen concentration that satisfies the combustion condition is specified. Therefore, the combustion air amount can be controlled by performing feedback control of the oxygen concentration so that the measured exhaust gas oxygen concentration becomes equal to the target oxygen concentration.

(2) Waste Combustion Rate Calculation and Control of Waste Movement Speed on Grate The waste combustion rate is evaluated by the solid weight equivalent weight of the combustion gas generated in a unit time, that is, the gasification rate G _{f of the} waste. . The gasification rate G _f of the waste can be calculated from the waste quality (u, m) calculated in (1) above, the furnace outlet exhaust gas temperature θ ₁ , the exhaust gas oxygen concentration O ₂ and the raw gas flow rate J.

The optimum moving speed of the dust on the grate is determined by the dust quality (u, m) and the gasification rate (G _f ) of the dust. Therefore, if the gasification rate G _f of waste, the waste calorie u, and the raw gas vapor amount m are calculated as input variables, the optimum feed rate of waste on the grate can be calculated.

Waste quality (U, M) and exhaust gas oxygen concentration O ₂
Is calculated as follows. Considering the waste incinerator as a physical distribution process, the heat input / output heat balance, gas flow balance, and oxygen flow balance in the model of FIG. 2 are as follows. Furnace and out heat balance _{U = Di d θ + Mi m} θ + (A t -A b) i a θ─── (1) u = di d θ + mi m θ + (a t -a b) i a θ─── (2) gas flow balance _{J = D + M + A t} -A b ────────────── (3) j = d + m + a t -a b ────────────── (4 ) oxygen flow rate balance _{0.21 (A t -A b) =} O 2 (J-M) ──────── (5) 0.21 (a t -a b) = o 2 (j-m) ─── ───── (6) In addition, in the equations (1) and (2), the blown air amount A _t
(A _t) heat input by the furnace, radiant heat from the exhaust heat and the furnace according to the incineration ash, because to the extent that may be practically negligible,
Excluded.

In the above equations (1) and (2), the heat generated by combustion, that is, the calorie of waste U (u), is the dry gas discharged from the furnace,
It shows that the heat balance is established by being distributed to water vapor and excess air. The above equations (3) and (4) show that the raw gas flow rate J (j) at the furnace outlet is such that GKg / Hr (1Kg / Hr) dust is
The theoretical amount of combustion air A _b (a _b) react with the dry gas amount D (d) which is generated by water vapor amount native to the raw gas M (m) and surplus air amount A _t -A _b (a _t -a _b ) equal to (Nm
³ / Hr value).

[0025] In the above (5) and (6), the left side, the oxygen concentration 0.21 and the excess amount of air in the atmosphere A _t -A _b (a
_{t- ab} ), which indicates the residual oxygen amount after combustion. O ₂ on the right side is a measurement value of the exhaust gas oxygen concentration measured by an oxygen concentration meter provided in the exhaust gas flue. This measured value is the volume ratio of oxygen in the dry gas volume of exhaust gas (volume of total gas volume less water vapor volume), that is, the oxygen concentration of dry gas. Since neither dry gas volume nor dry gas oxygen concentration differ between raw gas and exhaust gas, the right side of Eqs. (5) and (6) shows the amount of oxygen exhausted from the furnace. Equal to the left side of equations and (6).

The dry gas generation amount d and the theoretical combustion air amount a _b in the above equations (2) and (4) can be expressed by the linear approximation formula for u as shown in the process variable relational expressions and. (1) and (2) the enthalpy i _d θ, i _m θ and i _a theta in the equation, the process variable equation, and as shown in, is a function of temperature.

Raw gas flow rate J in the above equations (3) to (6)
(J) is given by the process variable relations and. Exhaust gas flow rate E at temperature θ ₂ (° C) including vaporized steam flow rate of injected water 1.24 (Nm ³ / Hr) is exhaust gas flow rate F (m / hr)
And the exhaust gas flue cross-sectional area σ (m ² ).
The process variable relational expression is an expression for converting the above product into Nm ³ / Hr. The process variable relational expression is the raw gas flow rate J (j) excluding the vaporized steam amount of the injection water contained in the exhaust gas.
It is shown that can be calculated.

The above equations (2), (4), and (6) can be rearranged into the following equations by applying the process variable relations (1) to (4). Furnace and out heat balance [1- (αCd-βCa) θ 1] u- (Cmθ 1 + q) m-Caθ 1 a t = (Cad o - Caa o) θ 1 ──────────── ──────── (7) gas flow balance (α-β) u + m + a t = j + a o -d o ─────── (8) oxygen flow rate balance _{-0.21βu + O 2 m + 0.21a t} = O ₂ j + 0.21 a _o ─── (9)

By applying the above-mentioned constants to the equations (7), (8) and (9), the following simple calculation equation is derived. (ΑCd-βCa) θ << 1 , α-β ≒ 0, Cdd o -Caa o ≒ 0, a o -d o << j furnace and out heat balance _{u- (0.36θ 1 +432) m-} 0.31θ 1 a _t = 0─────── (10) Gas flow balance m + a _t = j ─────────────────── (11) Oxygen flow balance −0.17 × 10 ^-3 u + O ₂ m + 0.21a _t = O ₂ j + 0.17─── (12)

The furnace outlet exhaust gas temperature θ ₁ and the exhaust gas oxygen concentration O ₂ are determined by measurement, and the raw gas flow rate j
Is calculated by the process variable relational expression. At this time, the above equations (10), (11) and (12) are expressed by u, m and a
It can be solved by considering it as a three-dimensional simultaneous linear equation with _t as an unknown. The concrete numerical values of the waste calorie u, the amount of raw water vapor m, and the amount of intake air thus solved are shown below.

[0031]

The oxygen concentration of the raw gas is determined by the waste calorie u, the raw gas water vapor amount m and the furnace outlet exhaust gas temperature θ ₁ .
It is calculated as follows based on the equations (2), (4), and (6). First, (4) a j-m obtained by transposition of m to the left side in equation (6) is substituted into the right side of the equation, clear the j and m Request a _t by the following (16).

Substituting the above equation (16) and the process variable relational expression and into the equation (2) and rearranging the result is as follows.

Substitution of process variable relational expression and dc _d
Considering ≒ dc _a , the exhaust gas oxygen concentration O ₂ is as follows (17)
It is calculated by the equation and (18).

By determining the raw gas oxygen concentration O _r corresponding to the desired furnace outlet exhaust gas temperature θ _r according to the above equation (18), the furnace outlet exhaust gas temperature can be established. The oxygen concentration O _{r of} raw gas is _expressed by θ _r and O _r of θ ₁ and O ₂ in the equation (18).
It is calculated by the following formula (19) by replacing with.

In the above equation (18), in the actual incineration process, the exhaust gas oxygen concentration O ₂ is determined by the furnace outlet gas temperature θ ₁
Of the above, and above
The equation (19) indicates that if the target raw gas oxygen concentration O _r is set, there is a target value of the furnace outlet gas temperature having the same value relationship with the set value.

According to the feedback control theory, as described above, when two set values having the same value relationship are established between two process quantities having different process points, a feedback control system for a process quantity having a high demand is provided. Stable control performance is obtained by cascading two feedback controllers so that a feedback control system of another process amount is included.

FIG. 3 is a system diagram showing an example of combustion air amount control. 3, 21 is an oxygen concentration setter for seeking and sets the exhaust gas oxygen concentration O _r by the expression (19). The exhaust gas oxygen concentration O _r set by the oxygen concentration setter 21 is compared with the exhaust gas oxygen concentration O ₂ measured by the exhaust gas oxygen concentration meter 14 provided in the flue 9 by the oxygen concentration PID controller 22, and The concentration PID controller 22 sends to the furnace outlet gas temperature PID controller 23 the furnace outlet exhaust gas temperature set value θ ′ _r that minimizes the difference between the two.

The furnace outlet gas temperature set value θ ′ _r and the furnace outlet gas temperature θ ₁ measured by the gas thermometer 10 at the gas outlet 1c are compared by the furnace outlet gas temperature PID controller 23, and The outlet gas temperature PID controller 23 sends a damper opening degree that minimizes the difference between the two to the damper driver 24, and the damper driver 24 opens and closes the damper 4 provided in the air supply pipe 6. By making the opening of the damper 4 coincide with the set opening in this way, the amount of combustion air in the incinerator 1 becomes appropriate, and the target exhaust gas oxygen concentration O _r and the furnace outlet gas temperature θ _r are obtained.

The burning rate of dust on the grate is calculated as follows. The solid waste equivalent weight of the amount of generated waste combustion gas is calculated as the solid waste disappearance rate, that is, the gasification rate G _{f of the} waste.
And In the equations (1), (3) and (5), the waste calorie U, the dry gas generation amount D and the theoretical combustion air amount _Ab are
Substituting by the product of u, d, a _b and G _f ,
The following equation is obtained from the process variable relational expression.

[0041] _{uG f = (αu + d o} ) G f C d θ + M (C m θ + q) + _{[A t - (βu + a O} ) G f ] C _a θ ─────────────── ──── (20) J = (αu + d o) G f + M + _{[A t - (βu + a O} ) G f ] ──── (21) 0.21 _{[A t - (βu + a O} ) G f ] = O ₂ ( J-M) ───────── (22)

The expressions (20), (21) and (22) are replaced by X ₁ G _f
When + X ₂ M + X ₃ unifies the format of the A _t = Y, is as follows. [U− (αu + d _o ) C _d θ + (βu + a _O ) C _a θ] G _f − (C _m θ + q) M −C _a θA _t = 0 ───────────────── ─────── (23) _{[(αu + d o) - (} βu + a O) ] _{G f + M + A t =} J────── (24) - 0.21 (βu + a O) + O 2 M + 0.21A t = O ₂ J─────── (25)

Equations (23), (24) and (25) are given by equation (10),
Similar to the case of the equations (11) and (12), it can be simplified as follows. uG _f − (C _m θ + q) M−C _a θA _t = 0 M + A _t = J −0.21 (βu + a _O ) G _f + O ₂ M + 0.21A _t = O ₂ J uG _f − (0.36θ + 432) M −0.31 θA _t = 0─────────── (26) M + A t = J───────────────────────── (27) (- 0.17 × 10 ^-3 u− 0.17) G _f + O ₂ M + 0.21A _t ＝ O ₂ J── (28)

[0044] (13), (14) to know and Equation (15) below the same manner as in the case _{θ = θ 1, O 2,} J, determined G _f, M and A _t as follows.

FIG. 4 is a system diagram showing an example of moving speed control of dust on the grate. In FIG. 4, 19 is a waste calorie calculator obtained by the equations (13) and (14),
Reference numeral 20 is a calculator of the gasification rate of refuse obtained by the equation (29), and 25 is a setter of the grate speed. The grate speed setter 25 obtains the current values of G _f , u, m from the gasification rate calculator 20 and the waste calorie calculator 19 and calculates the calculation formula V _rn (G _{f for} each grate. , U, m) output the optimal grate velocity to each grate. This allows the debris on the grate to be moved at an appropriate speed.

FIG. 1 is a system diagram showing an example of the control method of the present invention. As shown in FIG. 1, in the incinerator 1, a grate 2 including a dry grate 2a, a combustion grate 2b, and a post-combustion grate 2c is provided. Air supply port at the bottom of incinerator 1
An air supply pipe 6 is attached to the air supply pipe 1b. The air supply pipe 6 is provided with a blower 3 for feeding air into the furnace. The air supply pipe 6 on the inlet side of the blower 3 is provided with a damper 4. It is provided. In the present invention, the air supply pipe 6 is
The conventional branch pipe leading to the upper part of the incinerator 1 is not connected. A gas thermometer 10 is provided at the gas outlet 1c of the incinerator 1, and a jet water flow meter 13 for measuring the flow rate of the cooling water jetted from the nozzle 8 is provided in the gas cooling chamber 7.
Is provided. The exhaust gas flue 9 has an oxygen concentration meter 14,
A thermometer 15 and a velocity meter 16 are provided.

The throwing speed G _s of the dust thrown into the incinerator 1 by the crane 12 is measured by the dust meter 11, the furnace outlet exhaust gas temperature θ ₁ is measured by the gas thermometer 10,
Then, the injection water flow meter 13 measures the injection amount W of the cooling water from the nozzle 8 in the gas cooling chamber 7. Then, the oxygen concentration O ₂ of the exhaust gas (dry gas) is measured by the oxygen concentration meter 14, the temperature of the exhaust gas is measured by the thermometer 15, and the flow velocity F of the exhaust gas is measured by the flow velocity meter 16.

The dust injection speed G _s , furnace outlet exhaust gas temperature θ ₁ , water injection amount W, exhaust gas oxygen concentration (dry gas) O ₂ , gas cooler outlet gas temperature θ ₂ and exhaust gas flow rate F measured as described above are obtained. Based on the waste calorie calculator 19, the waste quality (U, m) is calculated. The raw gas flow rate J required as input data in the waste calorie calculator 19 is the output E of the exhaust gas flow rate calculator 17 for calculating the exhaust gas flow rate by θ ₂ and F ₂ and the output W of the water jet flow meter 13. It is given by the raw gas flow rate calculator 18 as an input.

The operator of the incinerator uses the waste calorie calculator 19
In addition to knowing the current waste quality (U, m), the optimum outlet gas temperature θ _r for incineration of the waste is indicated by the outlet gas temperature setter 29. Oxygen concentration setting device 21
Is the oxygen content O when the quality of waste (U, m) from the waste calorie calculator 19 and the target outlet gas temperature θ _r from the outlet gas temperature setter 29 are obtained and U, m and θ _r are simultaneously satisfied.
Calculate _r and output to oxygen concentration PID controller 22.

The oxygen concentration PID controller 22 uses the above-mentioned O _r as a set value and O ₂ as a feedback control value, and sets the temperature set value θ ′ _r that minimizes the difference between the two as the furnace outlet gas temperature PID.
Output to the controller 23. The furnace outlet gas temperature PID controller 23
The theta _'r to the set value, the theta ₁ as a feedback control value, the damper opening degree difference therebetween is minimized, the damper driver
Output to 24. In this way, the opening degree of the damper 4 provided in the air supply pipe 6 on the inlet side of the blower 3 is controlled by the damper driver 24.
The combustion air amount A _t when it becomes equal to the input command value, obtained target outlet gases temperature theta _r, stable control of the combustion air quantity is performed.

On the other hand, the waste gasification rate calculator 20 receives the waste calorie u, the raw gas flow rate J, the furnace outlet exhaust gas temperature θ ₁ and the exhaust gas oxygen concentration (dry gas) O ₂ as input, and deposits them on the grate 2. The gasification rate G _f of the solid waste being processed is calculated, and the result is output to the grate speed setter 25. The movement characteristics of the dust on the grate differ depending on the gasification rate G _f of the solid dust and the dust quality (U, m), and further, the dry grate 2a, the combustion grate 2b, and the post-combustion grate 2c. It also depends on each. Therefore, the grate speed setter 25 determines G _f , U,
It has a speed setting function V _rn (G _f , U, m) with m as an input, and is designed to instruct the optimum moving speed to each of the dry grate 2a, the combustion grate 2b, and the post-combustion grate 2c. There is.

As described above, according to the method of the present invention, the quality of waste is evaluated objectively and quantitatively in real time by the amount of generated heat per unit weight of waste and the amount of generated steam. The furnace outlet gas temperature, the amount of combustion air, etc. are controlled to values that match the current waste quality. Therefore, the waste can be burned in the optimum combustion state intended when the waste incinerator is designed.
Furthermore, the gasification rate of the refuse on the grate is evaluated objectively and quantitatively, and thereby the moving rate of the refuse on the grate is controlled to an optimum value. Therefore, the combustion of waste in the waste incinerator can be automatically and appropriately controlled according to the amount of waste deposited in the incinerator, the quality of the waste, and the like.

[0053]

As described above, according to the present invention,
When burning waste in a waste incinerator, the waste quality and the incineration rate of the waste can be known objectively and quantitatively, not by the subjectivity of the operator. Depending on the amount of dust accumulated in the inside, the quality of the dust, etc., it is automatically and appropriately controlled, and further, the moving speed of dust on the grate is automatically and appropriately controlled. Therefore, many industrially excellent effects are brought about, such as requiring no control personnel and enabling appropriate control for each grate.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of a control method of the present invention.

FIG. 2 is an explanatory diagram of process variables in a refuse incinerator for calculating a refuse quality, an oxygen concentration and a refuse incineration rate in the method of the present invention.

FIG. 3 is a system diagram showing an example of combustion air amount control in the method of the present invention.

FIG. 4 is a system diagram showing an example of moving speed control of dust on the grate in the method of the present invention.

FIG. 5 is a schematic explanatory view showing a conventional combustion control method.

[Explanation of symbols]

 1 incinerator, 1a furnace port, 1b air supply port, 1c gas outlet, 2 grate, 2a dry grate, 2b combustion grate, 2c post-combustion grate, 3 blower, 4 damper, 5 incinerator ash outlet, 6 Air supply pipe, 7 Gas cooling pipe, 8 Nozzle, 9 Flue, 10 Gas thermometer, 11 Waste meter, 12 Crane, 13 Water jet flow meter, 14 Oxygen concentration meter, 15 Thermometer, 16 Velocity meter, 17 Exhaust gas flow rate calculator, 18 Raw gas flow rate calculator, 19 Waste calorie calculator, 20 Waste gasification rate calculator, 21 Oxygen concentration setting device, 22 Oxygen concentration PID controller, 23 Furnace outlet gas temperature PID controller, 24 Damper Driver, 25 grate speed setter, 26 branch pipe, 27 damper, 28 damper drive, 29 outlet gas temperature setter.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Seiichi Noguchi 61-1 Ono-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Nihon Steel Pipe Heavy Industries Service Co., Ltd.

Claims (1)

[Claims] 1. A waste quality specified by the calorie of the input waste and the amount of steam of raw gas in the waste incinerator, based on the speed of inputting the waste, the temperature of the exhaust gas from the furnace outlet, the exhaust gas (dry gas) oxygen concentration and the exhaust gas flow rate. Based on the obtained waste quality, the optimum oxygen concentration for combustion of the waste is set, and the amount of air blown into the waste incinerator is controlled so that the oxygen concentration is set. On the other hand, on the other hand, based on the dust quality, the furnace outlet exhaust gas temperature, the exhaust gas (dry gas) oxygen concentration, and the exhaust gas flow rate,
A method for controlling combustion of refuse in a refuse incinerator, comprising: determining a gasification rate of thrown-in waste and controlling a moving speed of the refuse on a grate based on the obtained gasification rate.