JP2762054B2 - Combustion control method for fluidized bed incinerator - Google Patents

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 combustion in an incinerator provided with a fluidized bed so as to stably burn incinerated materials such as municipal solid waste and industrial waste.

[0002]

2. Description of the Related Art Conventionally, in a fluidized bed refuse incinerator, the composition of the material to be incinerated fluctuates, and various measures have been considered to cope with this. For example, Japanese Patent Application Laid-Open No. 4-904
Japanese Patent Application Laid-Open No. 09-2009 discloses that before an incinerated material such as municipal solid waste is introduced into a fluidized bed incinerator, the amount of the incinerated material is detected by a waste supply amount detection sensor, and the detected value is determined by a predetermined amount. A method and apparatus for corrective control of the combustion state when at high levels is described. Japanese Patent Application Laid-Open No. 6-42726 discloses that brightness in a fluidized bed incinerator for incinerating incinerators such as municipal waste is detected by a brightness detection unit, and the output of the brightness detection unit A fluidized bed furnace combustion control method and apparatus for controlling a combustion state is described.

[0003]

All of the above conventional combustion control methods deal with a sudden change in the amount of combustion and are not intended for stable operation of the furnace. Therefore, these publications do not describe anything about the stable operating conditions of the furnace. The present invention has been made in view of the above points, an object of the present invention, in order to perform a stable operation of the fluidized bed incinerator, to calculate the freeboard temperature and water-fuel ratio suitable for the set operating conditions, these It is an object of the present invention to provide a combustion control method for ensuring stable operation conditions of the furnace based on the calculated value of.

[0004]

In order to achieve the above object, a method for controlling the combustion of a fluidized bed incinerator according to the present invention comprises the steps of: Is configured to calculate the freeboard temperature and the water-fuel ratio suitable for the operating conditions set in, and to use these calculated values as control signals to control combustion. The water-fuel ratio is the ratio between the amount of cooling water in the fluidized bed [kg / H] and the supply amount of incineration material [kg / H]. The set operating conditions include:
The incinerator supply amount, fluidized bed air ratio, free board air ratio, fluidized bed temperature, and lower calorific value of the incinerated material are used.

[0005] In a fluidized bed furnace, it is important to stabilize the temperature of the fluidized bed, which influences the combustion speed, the temperature of the freeboard section which promotes the combustion of unburned gas, the oxygen concentration, and the like, in order to suppress CO and NOx. According to the method of the present invention, the temperature, the amount of air, and the amount of fluidized bed cooling water are determined according to the operating conditions, and stable operation of the furnace can be established.

[0006]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples, and can be implemented with appropriate modifications. FIG. 1 shows a schematic configuration of a fluidized bed refuse incinerator (hereinafter, referred to as a fluidized bed furnace) 10. In the fluidized bed furnace 10, primary air is blown by a primary air blower 12 into a wind box 1.
4, the fluidized medium of the fluidized bed 16 is fluidized, and the incinerated material is continuously charged into the fluidized bed 16 by the feeding device 18 to gasify and burn the incinerated material. The fuel gas is supplied to the free board section 20 by the secondary air blower 22.
To supply complete air and complete combustion. The fluidized bed furnace 10 is connected to a fluidized bed cooling water supply pipe 24 for supplying cooling water for controlling the temperature of the fluidized bed 16 within a certain range. 26 is a cooling water control valve, 28 is a primary air damper, 30 is a secondary air damper, 3
2 is an air distribution plate.

In the fluidized bed furnace 10 shown in FIG. 1, the energy balance and the mass balance of the fluidized bed 16 and the freeboard section 20 are expressed by the following equations (1) to (4). The equations for the amount of air are equations (5) and (6). _{C PG T B G GB = H} U K R G R + C PA T A G A1 -600G SP (1) C PG T G G GF = H U (1-K R) G R + C PA T A G A2 + C PG _{T B G GB (2) G} GB = (V 0 -A 0) K R G R + G A1 + (22.4 / 18) G SP (3) G GF = (V 0 -A 0) (1-K _R ) G _R + G _A2 + G _GB (4) G _A1 = λ _B K _R G _R A A ₀ (5) G _A2 = λ _F G _R A ₀ -G _A1 (6) Equations (3) and (3) Substituting equation (5) gives equation 1
(Equation (7)), and the fluidized bed cooling water amount _GSP is obtained.

[0008]

(Equation 1)

[0009] 'The _SP G' water ratio G and _SP = G _SP / G _R, Equation (2), (4), (6), is as (7) from Equation 2 (Eq. (8)) , The free board temperature _TG is G
_It can be obtained without depending on _R.

[0010]

(Equation 2)

As a result, the freeboard temperature _TG is determined by using the concept of the water-fuel ratio. It should be noted here that, as shown in Equation 2 (Eq. 8) is that the freeboard temperature T _G is not dependent on the incinerated supply amount G _R. The description of the symbols in the above equations (1) to (6), equation 1 (equation (7)), and equation 2 (equation (8)) is as follows. G _A1 : Primary air flow rate [Nm ³ / H] G _A2 : Secondary air flow rate [Nm ³ / H] T _A : Air temperature [° C] G _SP : Fluidized bed cooling water amount [kg / H] T _B : Flow Bed temperature [℃] T _G: freeboard temperature [℃] G _GB: fluidized bed unit gas amount [Nm ³ / H] G _GF: freeboard gas amount [Nm ³ / H] G _R: the incinerated supply Amount [kg / H] G ' _SP : Water-fuel ratio [-] C _PA : Specific heat of air [kcal / Nm ³ ℃] C _PG : Exhaust gas specific heat [kcal / Nm ³ ℃] H _U : Low calorific value of incinerated material [kcal / Kg] K _R : in-bed combustion rate [-] V ₀ : theoretical exhaust gas amount [Nm ³ / kg] A ₀ : theoretical air amount [Nm ³ / kg] λ _B : fluidized bed air ratio [-] λ _F : Free board air ratio [-]

FIG. 2 shows a combustion control system of a fluidized bed furnace to which the method of the present invention is applied. Be incinerated supply amount G _R, freeboard air ratio lambda _F, fluidized bed air ratio lambda _B, the fluidized bed temperature T _B and the incinerated lower heating value H _U is the set value of the operating conditions, air specific heat C _PA, Exhaust gas specific heat C _PG and in-layer combustion rate K _R
Is a substantially constant value and can be treated as a coefficient value. Therefore, the freeboard temperature _TG and the water-fuel ratio G ′ suitable for the operating conditions
_SP is required. By setting the obtained freeboard temperature _TG as a set value of temperature control using the operation amount as the feeding device speed, the temperature suitable for the operating conditions can be maintained.
Further, from the set free board air ratio λ _F and fluidized bed air ratio λ _B , the required primary air amount G _A1 and the required secondary air amount G _A2 are obtained by the above equations (5) and (6). , Set values for the primary air amount control and the secondary air amount control. As a result, the temperature in the fluidized bed furnace, the amount of fluidized bed cooling water and the amount of air are maintained at values suitable for setting the operating conditions, that is, stable operating conditions are maintained, and the incineration material is efficiently burned, and CO, NOx It works effectively in suppressing such factors.

The above items will be described in more detail with reference to FIG. From the set λ _F , λ _B , T _B , and H _U and the arithmetic units 36 and 38, the freeboard temperature _TG is obtained. The obtained freeboard temperature _TG and the measured value are used as a PID (proportion) with the operation amount as the feeding device speed.
al integral and derivative
e) By inputting to the controller 40, the freeboard section temperature is maintained at a temperature suitable for the operating conditions. Reference numeral 34 denotes a dust feeding device driving unit, and reference numeral 56 denotes a free board unit temperature detector. Further, the water-fuel ratio G ′ _SP is obtained from the set λ _F , λ _B , T _B , and H _U and the arithmetic units 36 and 38. Integrating the object to be incinerated supply amount G _R was set as the water-fuel ratio G _'SP obtained 68
, The fluidized bed cooling water amount G _SP is obtained,
The opening of the cooling water amount control valve 26 is determined. Also, the set value of the bed temperature T _B and the measurement value was an operation amount and a cooling water amount P
By inputting to the ID controller 42, the layer temperature is kept at the set value. 26 is a cooling water amount control valve, and 58 is a fluidized bed temperature detector. The theoretical air amount A ₀ is determined by the set H _U and the arithmetic unit 38, and the primary air amount G _A1 is determined by integrating the set λ _B , G _R , and coefficient value K _R by the integrator 66. By inputting the obtained primary air amount G _A1 and the measured value to the PID controller 44 in which the operation amount is the primary air amount, the primary air is kept at an amount suitable for the operating conditions. 28 is a primary air damper, 60 is a primary air flow meter. Furthermore, Motomari theoretical air amount A ₀ by the set H _U and computing unit 38, the integrator of the lambda _F, G _R set 6
By multiplying by 4, the total air amount is obtained. The secondary air amount G _A2 is obtained by subtracting G _A1 from the total air amount. By inputting the obtained secondary air amount G _A2 and the measured value to the PID controller 46 with the operation amount as the secondary air amount,
The secondary air is kept at an amount appropriate for the operating conditions. 30 is a secondary air damper, 62 is a secondary air flow meter.

[0014]

As described above, the present invention has the following effects. (1) Even if the operating conditions such as the amount of incinerated material supplied and the incinerated material lower calorific value change, the freeboard temperature and water-fuel ratio suitable for the operating conditions are obtained without depending on the amount of incinerated material supplied. By incorporating the calculation result into the combustion control system as a control signal, the freeboard temperature and the fluidized bed cooling water amount can be maintained at appropriate values, and stable operation of the fluidized bed furnace can be achieved. The generation of CO and NOx can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a fluidized bed furnace used to carry out the method of the present invention.

FIG. 2 is a system diagram showing a combustion control system in a fluidized bed furnace for carrying out the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fluidized-bed furnace 12 Primary blower 16 Fluidized bed 18 Dust supply device 20 Free board part 22 Secondary blower 26 Cooling-water-quantity control valve 28 Primary air damper 30 Secondary air damper 34 Dust supply device drive part 36 Arithmetic device 38 Arithmetic device 40 PID controller 42 PID controller 44 PID controller 46 PID controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/50 ZAB F23G 5/50 ZABR (72) Inventor Masato Hayashi 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi factory (72) Inventor Hidetaka Miyazaki 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi factory (72) Inventor Kaoru Koyano 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant (72) Inventor Hiroshi Fujiyama 1-3-1 Higashikawasaki-cho, Chuo-ku, Kobe Kawasaki Heavy Industries, Ltd.Kobe Head Office (72) Inventor Norio Toyoshima 1-3-1, Higashikawasaki-cho, Chuo-ku, Kobe Kawasaki Heavy Industries Kobe Head Office (58) Field surveyed (Int.Cl. ⁶ , DB name) F23G 5/50

Claims (2)

(57) [Claims] When burning an incinerated material in a fluidized bed incinerator, a freeboard temperature and a water / fuel ratio suitable for operating conditions set in the fluidized bed incinerator are calculated, and the calculated values are used as control signals for combustion. A method for controlling combustion in a fluidized bed incinerator, characterized by controlling. 2. The set operating conditions are as follows:
2. The combustion control method for a fluidized bed incinerator according to claim 1, wherein the fluidized bed air ratio, the freeboard portion air ratio, the fluidized bed temperature, and the lower heating value of the incineration material.