JPH0157245B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring moisture in incinerator exhaust gas and controlling the amount of incineration in an incinerator based on the moisture.

[Technical background]

For example, in a municipal waste incineration facility equipped with a waste heat boiler, the steam generated by the waste heat boiler is used in residual heat utilization equipment such as a turbine generator. , it is necessary to stabilize the amount of steam generated.

In order to stabilize the amount of steam generated, the amount of fuel supplied is generally controlled, but in the case of municipal waste incineration equipment, if the main focus is on stabilizing the amount of steam generated, it is necessary to When processing waste, the amount of waste to be processed increases and the waste pit becomes empty, which hinders continuous operation.Also, when processing waste with a high calorific value, the amount of waste to be processed decreases, causing the waste pit to become empty. There is a tendency for the amount of waste to increase, which impedes the original purpose of incinerators, which is waste disposal.

In order to continuously operate the incinerator equipped with a waste heat boiler while maintaining the appropriate amount remaining in the garbage pit, and to stabilize the amount of steam generated, the calorific value of the garbage must be measured online. It is essential to stabilize the amount of steam generated in accordance with the calorific value of this waste and the amount of waste that needs to be treated.

[Purpose of the invention]

An object of the present invention is to measure the amount of moisture in incinerator exhaust gas online, estimate the calorific value of waste based on this amount of moisture, and control the amount of incinerated garbage based on this calorific value.

[Structure of the invention]

The present invention detects the oxygen concentration at the waste incinerator outlet, the oxygen concentration in the flue, and the amount of combustion air, and measures the amount of moisture in the incinerator exhaust gas based on the detected oxygen concentrations and amount of combustion air. This method estimates the calorific value of the garbage based on the moisture content, and controls the appropriate amount of garbage to be incinerated based on the calorific value and the appropriate amount remaining in the garbage pit.

By the way, conventionally, there has been no known method or device for online measurement of moisture in incineration exhaust gas. It is difficult to collect samples to measure the moisture content of waste itself, and even if the moisture content of exhaust gas is measured in batches, this can be used to immediately control the amount of waste incinerated or the amount of evaporation from waste heat boilers. It was almost impossible to make any use of it.

Therefore, the present inventors conducted various studies on methods of measuring moisture in exhaust gas online and using the results to control the amount of waste incinerated, and as a result, they arrived at the present invention.

In the present invention, instead of directly measuring the moisture in the incineration exhaust gas, we measure the oxygen concentration at the incinerator outlet (or the oxygen concentration at the outlet of the cooling device) (raw gas measurement) and the flue gas oxygen concentration necessary for environmental monitoring (at room temperature). The two types of oxygen concentration (gas measurement) and the amount of combustion air are measured online, and by comparing and calculating these, the moisture in the incineration exhaust gas is measured, and the moisture content in the exhaust gas and the heat balance of the incinerator are calculated. The calorific value of the material to be incinerated (for example, municipal waste) is estimated from the relationship between This is to manage combustion.

Next, first, the method for measuring moisture in incinerator exhaust gas according to the present invention will be explained based on FIG.

In FIG. 1, reference numeral 21 is an incinerator, 22 is a hopper for supplying materials to be combusted, 23 is a combustion air blower, 24 is a gas cooling device (or waste heat boiler), 2
5 is an electrostatic precipitator, 26 is an induced blower, 27 is a chimney, 28 is an anti-exhaust device, 1 is a combustion air amount detection end, 2 is a combustion air amount transmitter, and 3 is a combustion air amount indicator, 4 is an incinerator outlet exhaust gas oxygen concentration detection end, 5 is an incinerator outlet exhaust gas oxygen concentration transmitter, 6 is an incinerator outlet exhaust gas oxygen concentration indicator, 7 is an exhaust gas moisture calculation section, 8 is an exhaust gas moisture indicator, 9 is a flue gas oxygen concentration detection end, 10 is a flue gas oxygen concentration transmitter, 11 is a flue gas oxygen concentration indicator, 12
13 shows an ash ejector of a gas cooling device, 13 shows an ash ejector of an electrostatic precipitator, and 14 shows an electrostatic precipitator purge device. Note that the indicators indicated by 3, 6, 8, and 11 are necessary only for checking the measured values.

Burnable materials, such as municipal garbage, are supplied to the incinerator from the combustible material supply hopper 22, and are combusted in the incinerator 21 by air supplied from the combustion air blower 23. After being cooled in a heat boiler (heat boiler) 24, it is sent to an electrostatic precipitator to remove accompanying dust, and then sent to a chimney 27 by an induced blower and discharged into the atmosphere.
On the other hand, the ash separated in the gas cooling device or the electrostatic precipitator is discharged from the gas cooling device ash discharging device 12 and the electrostatic precipitator ash discharging device 13, respectively, and is discharged from the ash discharging device 28.
is carried out to a predetermined location. During this time, gas leakage from the gas cooler ash discharger 12 and the electrostatic precipitator ash discharger 13 is extremely small.

Next, the combustion air amount detection mechanism, oxygen concentration detection mechanism, and moisture measurement mechanism in exhaust gas of the present invention will be explained.The combustion air amount detection end 1 detects the air amount, and the combustion air amount transmitter 2 transmits the amount of air. and is indicated by the combustion air amount indicator 3 (wet base).

Further, the flue gas oxygen concentration is detected by the flue gas oxygen concentration detection end 9, and the flue gas oxygen concentration transmitter 1
0 and is indicated by the flue gas oxygen concentration indicator 11 (dry base). On the other hand, the incinerator outlet or incinerator outlet exhaust gas oxygen concentration is detected by the incinerator outlet exhaust gas oxygen concentration detection end 4, transmitted by the incinerator outlet exhaust gas oxygen concentration transmitter 5, and indicated by the incinerator outlet exhaust gas oxygen concentration indicator 6. (wet base). The value indicated by this incinerator outlet exhaust gas oxygen concentration indicator is converted into a dry base by the calculation unit 7 based on the data indicated in 3 and the data indicated in 11, and the value is indicated in 8. It is.

The calculation in the calculation section 7 will be explained as follows.

x: Amount of oxygen in gas (Nm ³ /H) y: Amount of gases other than O ₂ and H ₂ O such as N ₂ , CO ₂ , NO _X , etc. in gas (Nm ³ /H) z: Oxygen in exhaust gas at incinerator outlet Amount of air leaking from the concentration detection end 4 to the flue gas oxygen concentration detection end 9 (Nm ³ /H) Dry h ₁ : Amount of moisture at the incinerator outlet exhaust gas oxygen concentration detection end 4 (Nm ³ /H) 100h ₂ : Moisture content in the air (%) Q _A : Reading of the combustion air amount indicator (Nm ³ /H) 100A: Reading of the incinerator outlet exhaust gas oxygen concentration indicator (%) 100B: Reading of the flue gas oxygen concentration indicator Reading (%) Q _G : Amount of combustion gas (Nm ³ /H) Then, reading of incinerator outlet gas or boiler outlet gas oxygen concentration meter A A=x/x+y+h ₁ (1) Reading of flue oxygen concentration meter B B=x+0.21z/x+y+z (2) Assuming the oxygen concentration in the air is 21% From (1) x=A/1-A(y+h ₁ ) (Nm ³ /H) (3) From (2) x =B/1-By+B-0.21/1-Bz (Nm ³ /
H) (4) From (3) and (4), h ₁ = B-A/A (1-B) y + (B-0.21) (1-A)
/A(1-B)z (Nm ³ /H) (5) Here, the relationship between the total gas amount (dry) and the combustion air amount is Q _G = K・Q _A・(1-h ₂ )= x+y (Nm ³ /H)
(6) From (3) and (6), x=A {K・Q _A・(1−h ₂ )+h ₁ } (Nm ³ /H)
(7) Here, C=B-A/A(1-B) D= (B-0.21)(1-A)/A(1-B) Q _D =Q _A (1-h ₂ ) h ₁ = C・y+D・z (Nm ³ /H) (5)′ From (5)′, (6), and (7), h ₁ =C(K・Q _D −x)+D・z (Nm ³ / H)
(5)″ x=A{K・Q _D +C(K・Q _D −x)+D・z} (Nm ³
/H)(7)' (1+C・A)x=A{K・Q _D +C・K・Q _D +D・z} x=A/1+CA{K・Q _D +C・K・Q _D +D・z} (N
m ³ /H)(7)″ Therefore, the gas oxygen concentration (dry) x′ at the incinerator outlet or boiler outlet is x′=x/K・Q _D =A/(1+C・A)K・Q _D K・Q _D {
K・Q _D +C・K・Q _D +D・z} =A(1+C)/1+C・A+A・D・z/(1+C
・A) K・_Q DHere I=A(1+C)/1+C・A K=0.97(1−h ₂ )/1−0.0014x′×100=0.951
/1-Lx' then x'=I+A・D・z/(1+C・A)・0.951・Q _D /(
1-Lx') = I+A・D・z(1-Lx')/(1+C・
A)・0・951・Q _DHere , J=A・D・z/0.951・Q _D・(1+CA) Then x′=I+J−JLx′ (1+JL)x′=I+J 100x′=I+J/1+JL× 100 (%) (7) From (5)″, h ₁ = C{0.951・Q _D /1−L・x′(1−x′
)}+Dz (Nm ³ /H) 100h′ ₁ = h ₁ (1−L・x′)/0.951・Q _D (%) Next, it is possible to measure the moisture in exhaust gas as described above. If so, the amount of cooling water introduced into the incinerator can be easily determined, and the amount of water in the waste can be easily determined by subtracting the amount of cooling water introduced into the incinerator from the amount of moisture in the exhaust gas. On the other hand, heat input to the incinerator (calorific value brought in for fluidizing air, calorific value brought in by secondary air, calorific value brought in by garbage) and heat output (sensible heat taken out from exhaust gas, heat taken out from circulating sand, heat amount of evaporation from the furnace top spray, heat amount taken out from fly ash, and heat released) Since the calorific value in the furnace can be calculated from the calorific value (heat value), the calorific value of the waste can be determined from the relationship between this calorific value and the moisture in the waste, and the appropriate amount of waste to be processed can be calculated according to this calorific value of the waste. By calculating the amount of steam generated (in the waste heat boiler) corresponding to the amount of waste processed and setting this value in the evaporation amount controller, the system as a whole can operate optimally with a stable amount of steam generated. It becomes possible to maintain the state.

Next, based on FIG. 2, an example of controlling the amount of waste incinerated in an incinerator based on the moisture in exhaust gas will be explained.

In FIG. 2, the symbols 1, 2, 4, 5, 7,
9, 10, 21, 22, 23, 25, 26, 27
and 28 have the same meanings as the symbols in FIG. 1, 24' is a waste heat boiler, 31 is a cooling water flow rate detection end,
32 is a cooling water flow rate transmitter, 33 is a waste treatment amount detection end, 34 is a waste treatment amount transmitter, 35 is a steam amount detection end, 36 is a steam amount transmitter, 37 is a steam amount controller,
38 is a boiler drum pressure detection end, 39 is a boiler drum pressure transmitter, 40 is a boiler drum pressure regulator, 41 is a boiler drum pressure operation end, 42 is a municipal waste calorific value calculation unit, and 43 is a municipal waste calorific value average value calculation unit. 44 is an appropriate evaporation amount calculation unit, 45 is an appropriate throughput amount calculation unit, 46 is a comparison calculation unit for the appropriate throughput and average throughput, and an appropriate evaporation amount calculation start command unit, 47 is a dust supply device, and 48 is a dust supply unit. The machine drive motor is shown.

First, as explained based on FIG. 1, the moisture content in the exhaust gas is determined in the exhaust gas moisture calculation unit 7, and the moisture content is transmitted to the municipal waste calorific value calculation unit 42, which calculates the amount of moisture in the exhaust gas. , the amount of cooling water detected by the cooling water flow rate detection end 31 and transmitted by the cooling water flow rate transmitter, and the amount of waste to be processed detected by the waste amount detection end 33 and transmitted by the waste amount transmitter 34; The calorific value of the municipal waste is calculated based on the moisture content of the exhaust gas, and the calorific value is transmitted to the municipal waste calorific value average calculating section 43, which calculates the average value of the calorific value of the municipal waste, and calculates the average value to an appropriate value. Calorific value calculation unit 4
4. In the appropriate evaporation amount calculation unit 44, the average value of urban waste calorific value transmitted from 43,
and the appropriate amount of municipal waste to be processed, which is calculated by the appropriate amount calculation unit 45 based on the amount of garbage brought in, the amount remaining in the garbage pit, and the desired remaining amount (appropriate amount remaining), and is transmitted to the appropriate amount calculation unit 44 of evaporation. Calculate the appropriate evaporation amount (appropriate evaporation amount in the waste heat boiler). If the appropriate amount of evaporation calculated by this calculation is manually or automatically set in the steam amount controller 37, a steam amount signal detected by the steam amount detection end 35 and transmitted by the steam amount transmitter 36 can be set. Based on the value set on the steam controller, the steam controller 37 detects whether the amount of waste being supplied to the incinerator is excessive or insufficient, and if there is a shortage, the signal is sent to the dust supply Drive motor 4
8 and controls to increase the amount of waste supplied.

The pressure of the boiler drum is detected by the boiler drum pressure detection end of the waste heat boiler 24', and this signal is transmitted to the boiler drum pressure regulator by the boiler drum pressure transmitter, and the pressure regulator adjusts the pressure based on the signal. , the boiler drum pressure operating end (for example, a valve) is operated in the opening or closing direction so that the boiler drum pressure becomes a predetermined (constant) pressure.

By controlling as described above, it is possible to maintain a stable amount of steam generation in the waste heat boiler while maintaining an appropriate amount of waste to be treated.

In addition, if the previously calculated appropriate processing amount is no longer satisfactory due to changes in waste quality (for example, moisture content of waste) or changes in the amount of waste brought in, the calculation section for comparing the appropriate processing amount and the average processing amount , the appropriate evaporation amount calculation unit 4 based on the difference between the appropriate processing amount and the average processing amount.
4, a calculation start command is issued, the appropriate amount of evaporation is recalculated, and this value is reset to the steam amount controller 37, thereby making it possible to obtain a stable amount of steam generation at the new balance point.

[Brief explanation of drawings]

FIGS. 1 and 2 are process diagrams showing one embodiment of the present invention. 1... Combustion air amount detection end, 3... Combustion line air amount indicator, 4... Incinerator outlet exhaust gas oxygen concentration detection end, 6... Incinerator outlet exhaust gas oxygen concentration indicator, 7
...Exhaust gas moisture calculation section, 8...Exhaust gas moisture indicator, 9...Flute gas oxygen concentration detection end, 11...Fue gas oxygen concentration indicator, 21...Incinerator, 22...
... Hopper for supplying materials to be combusted, 23 ... Combustion air blower, 24 ... Gas cooling device, 25 ... Electric precipitator, 26 ... Induced blower, 27 ... Chimney, 28
...Ash transport device, 31...Cooling water flow rate detection end, 3
3... Garbage incineration amount detection end, 35... Steam amount detection end, 37... Steam amount controller, 38... Boiler drum pressure detection end, 40... Boiler drum pressure regulator, 42... Municipal waste calorific value Calculating section, 43...Municipal garbage calorific value average value calculating section, 44...Appropriate calorific value calculating section, 45...Appropriate processing amount calculating section, 46...Comparison calculating section between the appropriate processing amount and the average processing amount.

Claims (1)

[Claims] 1 Detect the oxygen concentration at the incinerator outlet, the oxygen concentration in the flue, and the amount of combustion air, measure the moisture in the incinerator exhaust gas based on the detected oxygen concentration and amount of combustion air, and measure the moisture in the incinerator exhaust gas. A method of controlling the amount of garbage, etc. incinerated in an incinerator based on