JPS6089615A - Control method for amount of refuse to be incinerated in incinerator - Google Patents

Abstract

PURPOSE:To properly control an amount of refuse incinerated through estimation of the calorific value of refuse, based on an amount of a water content, by a method wherein, through detection of oxygen concentration at the outlet of an incinerator, oxygen concentration in smoke passage, and an amount of the air for combustion, an amount of water content in exhaust gas from the incinerator is measured by means of an on-line system. CONSTITUTION:Oxygen concentration is detected by a fuel passage oxygen concentration detector 9, is transmitted by a fuel passage oxygen concentration transmitter 10, and is indicated by a fuel passage oxygen concentration indicator 11. Meanwhile, oxygen concentration at the outlet of an incinerator or in exhaust gas from the incinerator is detected by a detector 4 for oxygen concentration in exhaust gas at the outlet of the incinerator, is transmitted by a transmitter 5 for oxygen concentration in exhaust gas at the outlet of an incinerator, and is indicated by an indicator 6 for oxygen concentration in exhaust gas at the outlet of an incinerator. A value, indicated by the indicator 6 for oxygen concentration in exhaust gas at the outlet of an indicator, is converted into a dry base by a computing part 7, based on data indicated by an indicator 3 for an amount of the air for combustion and the indicator 11 for oxygen concentration in gas in a fuel passage to indicate it on an indicator 8 for water content in exhaust gas.

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 generated by a turbine! It is used in residual heat utilization equipment such as steam machines, but in order to use steam effectively, 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 facilities, the main focus is on stabilizing the amount of steam generated (and When processing waste with the same calorific value, the amount of waste to be processed increases and the waste bit becomes empty, which hinders continuous operation.When processing waste with the same calorific value, the amount of waste processed decreases and the waste bit becomes empty. The amount will tend to increase, which will hinder the incinerator's original purpose of waste disposal.

In order to continuously operate the incinerator equipped with a waste heat boiler and stabilize the amount of steam generated while maintaining the remaining amount of waste bits, it is necessary to measure the calorific value of the waste 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 moisture content in the incinerator exhaust gas in a short on-line manner, estimate the calorific value of waste based on this moisture content, and control the amount of garbage to be incinerated 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 is a method of estimating the calorific value of the garbage based on the moisture content, and controlling the appropriate amount of garbage to be incinerated based on the calorific value and the appropriate remaining amount of garbage bits.

By the way, no method or device for measuring moisture in incineration exhaust gas on-line has been known so far. 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 batchwise, this can be used to immediately control the amount of waste incinerated or to control the amount of evaporation in waste heat boilers. It was almost impossible to make 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 (oxygen concentration as measured by the cooling device), we measure the oxygen concentration at the incinerator outlet (raw gas measurement) and the flue gas oxygen necessary for environmental monitoring. The oxygen concentration (normal temperature gas measurement) and the amount of combustion air are measured online, and by comparing and calculating these, the moisture in the combustion exhaust gas is measured, and the amount of moisture in the exhaust gas and the amount of air in the incinerator are measured. The calorific value of the material to be incinerated (for example, municipal waste) is estimated from the relationship with the heat balance of This is to manage the combustion of the incinerator.

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

In the N1 diagram, 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), 25 is an electric precipitator, 26
indicates an induced blower, 27 indicates a chimney, 28 indicates an ash removal device,
In addition, 1 is a combustion air amount detection end, 2 is a combustion air amount transmitter, 3 is a combustion air amount indicator, 4 is an incinerator exit exhaust gas oxygen condensation detection end, and 5 is an incinerator exit 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 quality transmitter, 11 is a flue Gas oxygen concentration indicator, 12 is gas cooling device ash ejector, 13
14 indicates an electrostatic precipitator ash discharger, and 14 indicates an electrostatic precipitator purge device. Note that the indicators indicated by 3, 6, and 8.11 are necessary only for checking the measured values.

A hopper 22 for supplying combustible materials such as municipal garbage
The air is supplied to the incinerator from the combustion air blower 23, and the combustion gas is combusted in the incinerator 21. After being cooled in the gas cooling device (or waste heat boiler) 24, the combustion gas is subjected to electrostatic precipitator. The ash is sent to a gas cooler 25 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 a gas cooling device or an electrostatic precipitator is sent to a gas cooling device, respectively. The ash is discharged from the ash discharging machine 12 and the electric precipitator ash discharging machine 13, and is carried out to a predetermined place by the ash discharging device 28. During this time, the ash discharging machine 1 of the gas cooling device
2 and the electrostatic precipitator ash ejector 15 are extremely small.

Next, the total combustion air amount detection mechanism, relative density detection mechanism, and moisture measurement mechanism in exhaust gas of the present invention will be explained.
The amount of air is detected by the e-firing air base detection end 1, transmitted by the combustion air amount transmitter 2, and indicated by the combustion air amount indicator 3 (wet base).

In addition, the flue gas oxygen concentration is detected by the flue gas oxygen hardness detection end 9, transmitted by the flue gas oxygen concentration transmitter 10, and indicated by the flue gas oxygen concentration indicator 11 (dry base). The incinerator exit or incinerator exit exhaust gas concentration level is detected by the incinerator exit exhaust gas oxygen level detection terminal 4, and is transmitted by the incinerator exit exhaust gas oxygen level transmitter 5. The value indicated by the exhaust gas cough symptom indicator 6 (wet basis) is then converted into the value indicated by the incinerator outlet exhaust gas oxygen concentration indicator 6 and the data indicated by 11. Based on this, the calculation unit 7 converts it into a dry base and instructs it to 8.

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

X: Oxygen in gas (Nm/H) y: N2 in gas. CO2, NOx etc.02. Amount of gas other than H20 (Mm/H) 2: Amount of air leaking from incinerator outlet exhaust gas oxygen concentration detection end 4 to flue gas oxygen fineness detection end 9 (Nm3/H nodry hl: Incinerator exit exhaust gas oxygen concentration detection Moisture content at end 4 (Nm/H) 1ooh2: Moisture content in the air (%) QA: Reading of combustion air amount indicator (Nm3/H) 10
0A: Reading of the exhaust gas oxygen concentration indicator at the incinerator outlet [%] 100B: Reading of the flue gas acid concentration indicator (%) QG
: Amount of combustion gas (Nm3/H).

Incinerator outlet gas or boiler exit locus oxygen alpha reading A Reading of flue oxygen concentration meter B 13 (3) (From 41, the relationship between the total gas amount (dry) and the combustion air amount is Q, = K - QA・(1-h2) = x + y (N
m /H) (61 +31, +61 x-AfK-QA・(1-h2) 10h11 (Nm3/H
] (7) Here, A(1-B) A(1-B, I QD=QA(1-h2) and h1=: C* y+D*z (Nm /H) (
51' (5V, +6), (7nyo 9 h1=OCK*Q, -, X) +D@z (Nm/H
)(5)! x=A(Kl;!D1C(KQD-x)+D
-zl (Nm3/H) (71'<A+a-A)x=A
(K-qD+a@-qD-4-rraz) (Nm/H
) (7)” Therefore, the gas oxygen concentration at the incinerator outlet or boiler outlet (
dry) x' is x'= - e QD where 1+C-A is -D-z where A*Dsz J=.

0.95111QD・(1+OA,), then x'= I-)-J-J L x' (1+JL) If it becomes possible to measure moisture, the amount of cooling water introduced into the incinerator can be easily determined, so by subtracting the amount of cooling water introduced into the incinerator from the moisture in the exhaust gas, the amount of moisture in the waste can be easily determined. On the other hand, the heat input to the incinerator (the amount of heat brought in by the fluidizing air, the amount of heat brought in by the secondary air, the amount of heat brought in by the sludge) and the heat output (sensible heat taken out of the exhaust gas, the amount of heat taken out from the circulating sand, the amount of evaporation heat from the furnace top spray, Since the calorific value in the furnace can be calculated from the amount of heat taken out of the fly ash and the amount of heat released, the calorific value of the garbage can be calculated from the relationship between this calorific value and the moisture in the garbage, and appropriate garbage treatment can be carried out according to the calorific value of this garbage. 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 device can maintain a stable amount of steam generated. It becomes possible to maintain optimal operating conditions as a whole.

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, 3
1 is a cooling water flow rate detection end, 32 is a cooling water flow rate transmitter, 63
34 is a waste processing amount transmitter, and 35 is a steam amount detection end.

56 is a steam amount transmitter, 37 is a steam amount controller, 6B is a boiler drum pressure detection end, 39 is a boiler drum pressure transmitter %
40 is the boiler drum pressure regulator.

41 is a boiler drum pressure operating end %; 42 is a municipal waste calorific value calculation section; 43 is a municipal waste calorific value average value calculation section; 44 is an appropriate evaporation amount calculation section; 45 is an appropriate processing amount calculation section; 46 is an appropriate processing amount calculation section. An average processing amount comparison calculation unit and an appropriate evaporation amount calculation start command unit.

47 is a dust feeder, and 48 is a dust feeder driving moke.

First, as explained based on FIG. 1, the exhaust gas moisture calculation section 7 calculates the moisture in the exhaust gas.

The amount of water is transmitted to the urban garbage calorific value calculation section 42, and the urban garbage calorific value calculation section calculates the amount of cooling water detected by the cooling water flow rate detection end 61 and transmitted by the cooling water flow rate transmitter.
The calorific value of municipal waste is calculated based on the amount of waste to be processed detected by the waste amount detection terminal 33 and transmitted by the waste amount transmitter 34 and the moisture content of the exhaust gas, and the calorific value of the municipal waste is calculated as the urban waste heat value. It is transmitted to the quantity average calculating section 43, which calculates the average value of the urban waste calorific value, and transmits the average value to the appropriate evaporation amount calculating section 44. The appropriate evaporation amount calculation unit 44 calculates the urban waste calorific value average value transmitted from 43 and the garbage carry-in lid,
The appropriate amount of evaporation (
Calculate the appropriate evaporation k) in the waste heat boiler. If the appropriate evaporation i calculated by this calculation is manually or automatically set in the steam amount controller 37, the steam amount signal detected by the steam amount detection end 55 and transmitted by the steam amount transmitter 66 is Based on the value set on the steam volume controller 37, the amount of waste supplied to the incinerator is determined by the steam volume controller 37.
If there is a shortage, the signal is transmitted to the dust feeder drive motor 48 to control the dust supply amount to increase.

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 (-predetermined) 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 treatment.

Note that if the previously calculated appropriate processing amount is not satisfactory due to changes in waste quality (e.g. moisture content of the waste) or changes in the amount of waste brought in, etc., the calculation unit for comparing the appropriate processing amount and the average processing amount In.

By issuing a calculation start command to the appropriate evaporation amount calculation unit 44 based on the difference between the appropriate amount of processing and the average amount of processing, recalculating the appropriate amount of evaporation, and resetting the value to the steam amount controller 67.
A stable amount of steam generation can be obtained at the new balance point.

[Brief explanation of the drawing]

FIGS. 1 and 2 are process diagrams showing one embodiment of the present invention. 1... Combustion air amount detection end 7... Exhaust gas moisture calculation unit 8... Exhaust gas moisture indicator 9... Flue gas acid system concentration detection end 11... Flue gas oxygen concentration indicator 21 . . . Incinerator 22 . . . Burnable material supply humper 26 . . . Combustion air blower 24 . . . Gas cooling device 25 . . . Electric precipitator 26 . ... Ash transport device 31 ... Cooling water flow rate detection end 63 ... Garbage incineration amount detection end 35 ... Steam amount detection end 67 - ... Steam amount regulator 38 ... Boiler drum pressure detection end 40 ...Boiler drum pressure regulator 42...Municipal waste calorific value calculation section 43...Municipal waste calorific value average value calculation section 44...Appropriate calorific value calculation section 45...Appropriate processing amount calculation section 46. ... Comparison calculation unit for appropriate processing amount and average processing amount Patent applicant: Ebara Corporation Agent: Hirodo Nakamoto, Akito Inoue, Katsura Yoshimine

Claims (1)

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