JPH09178147A - Operation method of refuse burning equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation method of refuse burning equipment capable of stably supplying a proper amount of refuse into a burning furnace in response to the required amount of heat produced in the burning furnace. SOLUTION: In refuse burning equipment for supplying refuse into a burning furnace using a refuse supply crane, a pressure detector 3a and a backet opening detector 3b are arranged on a backet 3 provided on the refuse supply crane. A stress ratio of refuse is estimated on the basis of the amount of a change in an indicated value on the pressure detector when the opening of the backet holding the refuse is narrowed. The produced heat amount of the refuse is estimated from a correlation equation between the preestimated produced heat amount of the refuse to control the supplied heat amount of the refuse. The foregoing correlation equation is corrected by reversely estimating the produced heat amount of the refuse during combustion from the flow rates and temperatures of air, an auxiliary fuel, and cooling water applied to the refuse burning furnace, and the temperature and the dissipated heat amount of combustion exhaust gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a refuse incinerator, and more particularly, to a method for operating a refuse incinerator that incinerates an incinerator that has a large variation in calorific value at the time of incineration due to seasonal variations and collection areas. Regarding control method.

[0002]

2. Description of the Related Art In a refuse incineration facility provided with a power generation system for generating power using waste heat of an incinerator, it is required to generate a heat amount corresponding to a power generation request in order to obtain stable power generation. The calorific value of the incinerator fluctuates depending on the amount (waste supply amount) and quality (waste calorific value) of the waste that is put into the incinerator, so the relationship between the calorific value of the incinerator and the waste supply amount and the waste calorific value Accurately grasping is important for generating a heat quantity corresponding to the power generation request and obtaining stable power generation.

By the way, the amount of heat generated from municipal waste collected from various places varies greatly depending on the collection area, collection time, weather, season and the like. In addition, the collected municipal waste is stored in the garbage pit provided in the garbage incinerator,
The waste is transported by the bucket of the garbage crane and put into the incinerator, but if the heat generation amount of the waste accumulated in the waste pit is uneven due to the storage location in the waste pit, the waste supply amount to the incinerator will be high. Even if controlled accurately, the heat value of the incinerator cannot be controlled stably. In view of such circumstances, conventionally, a method has been adopted in which the volume of the waste pit is made sufficiently large and the waste in the pit is appropriately stirred by a waste crane to homogenize the waste and reduce fluctuations in the heat value of the waste. There is. However, it is practically difficult to sufficiently agitate the waste in the waste pit under the circumstances where the waste trucks frequently carry in the waste during the day. Therefore, it is difficult to control the heat generation amount of the incinerator in a stable manner.

On the other hand, as a method of obtaining the heat value of waste by industrial analysis, it is described in "Various Waste Incineration Facility Test Manual" edited by Environment Improvement Division, Water Environment Department, Environmental Sanitation Bureau, Ministry of Health and Welfare. Since the calorific value of dry waste is measured by a combustion meter, it is difficult to measure it in real time during operation of the incinerator. Therefore, it is necessary to develop a method that can measure the heat value of waste in real time.However, in an actual waste incinerator, it is difficult to measure the amount of waste supplied to the incinerator in real time. When the internal temperature (furnace temperature) rises or falls, it is difficult to understand whether this is due to the fluctuation of the heat value of waste or the increase or decrease of the waste supply amount.

In order to solve such a problem, conventionally, a proposal has been made to obtain the heat value of waste in association with the bucket of a waste supply crane. Japanese Patent Laid-Open No. 1-1146
No. 10 publication describes a method of obtaining an apparent specific gravity from the weight of the garbage held by the bucket and the volume of the bucket, and estimating the heat generation amount from the correlation between the apparent specific gravity and the lower heating value obtained in advance, In addition, JP-A-5-2153
Japanese Unexamined Patent Publication No. 18 discloses a method of calculating the specific gravity of dust from the volume of dust estimated from the holding angle of the dust crane bucket and the weight of dust caught by the bucket.

[0006]

However, since the former method obtains the apparent specific gravity of dust with the bucket volume kept constant, the apparent specific gravity of dust cannot be obtained accurately. That is, the bucket of the garbage supply crane does not always grab a fixed volume of garbage, and may grab a smaller amount than the volume of the garbage bucket, or it may grab the garbage while it is protruding from the bucket.
When the apparent specific gravity of dust is calculated with the bucket volume kept constant, the calculated value becomes inaccurate. Further, the latter method detects the gripping angle of the bucket and estimates the volume of dust, so that the apparent specific gravity of dust can be calculated more accurately than when the apparent specific gravity of dust is determined with the bucket volume kept constant. However, also in this case, since the gripping angle of the bucket and the amount of dust caught by the bucket do not correspond exactly, the calculated value of the apparent specific gravity of dust becomes inaccurate.

Furthermore, even if there is a certain correlation between the specific gravity of the refuse and the amount of heat generation under certain conditions, the correlation changes depending on the collection area of the refuse, the collection time, the season, the weather and other conditions. Therefore, it is not possible to operate the appropriate waste incineration facility using the calculated waste heat generation value unless appropriate corrections that take these conditions into consideration are added.

The present invention has been made in order to eliminate the disadvantages of the prior art, and its object is to incinerate a proper amount of refuse in a stable manner according to the required calorific value of the incinerator. It is to provide a method of operating a refuse incineration facility that can be supplied into a furnace.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, firstly, in a refuse incinerator for supplying refuse into an incinerator by using a refuse supply crane, an inner surface of a bucket of the refuse supply crane. Install a pressure detection device in the, and estimate the waste heat generation amount from the correlation equation between the amount of change in the indicated value of the pressure detection device with respect to the bucket opening when catching dust and the waste heat generation amount obtained in advance. The configuration is such that the amount of heat supplied is controlled.

Secondly, in the above-mentioned first means, the amount of dust during combustion is determined from the flow rate and temperature of air, auxiliary fuel and cooling water added to the refuse incinerator, the temperature of combustion exhaust gas, the amount of heat released, etc. The heat generation amount is back-calculated, the correction value is used as a correction value, and the waste heat generation amount is estimated while the correlation expression between the change amount of the pressure detection device and the heat generation amount is corrected to control the waste heat supply amount.

The bucket of the refuse supply crane is provided with a pressure detector for detecting the pressure acting on the inner surface of the bucket and a detector for opening the bucket, and the above-mentioned pressure detector when the bucket for catching dust has a large opening. If the difference or ratio between the output value of the pressure detector and the output value of the pressure detector when the dust is compressed by narrowing the opening degree of the bucket from that state, the magnitude of the stress ratio of the dust caught in the bucket can be obtained. You can Since there is a close relationship between the stress ratio of waste and the heat value of waste, and these relationships can be obtained in advance in a laboratory, the pressure detector and bucket opening detection during operation of the waste incineration facility can be detected. If the stress ratio of dust is calculated from the output signal of the container,
It is possible to accurately estimate the calorific value of the waste that is grabbed by the bucket and put into the incinerator, from the correlation expression between the waste stress ratio and the waste heat value that is obtained in advance in the laboratory. Therefore, it is possible to appropriately control the waste supply amount so that the heat input is constant, or to appropriately control the waste supply amount to match the heat amount required by the exhaust heat recovery device such as the subsequent waste heat boiler. it can.

Note that the heat generation amount of waste during combustion does not change only depending on the magnitude of the stress ratio of the waste, but the flow rate and temperature of combustion air added to the waste incinerator, the amount of auxiliary fuel, and the flow rate of cooling water. It also varies depending on temperature and temperature. Therefore, by calculating the heat balance of the waste incinerator, the actual heat generation amount of waste in the waste incinerator is back-calculated, and the correlation expression between the waste stress ratio and the waste heat generation amount is appropriately corrected with this back-calculated waste heat generation amount. By doing so, a more accurate waste supply amount can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION First, an example of a refuse incineration facility in which an operating method according to the present invention is executed will be described with reference to FIG. In FIG. 1, 1 is a waste pit for storing waste A, 2 is a crane for supplying waste A, 3 is a bucket provided for the crane 2, 4 is a dust supply device, 5 is a waste incinerator, and 6 is waste incineration. An exhaust heat recovery device such as an exhaust heat recovery boiler for effectively utilizing the exhaust heat of the furnace 5, 7 is an air preheater for preheating combustion air supplied to the refuse incinerator 5, and 8 is dust and harmful in exhaust gas. 1 shows a dust remover for removing substances.

The dust supply device 4 includes a hopper 11 for receiving dust, a screw feeder 12 for pumping the dust received by the hopper 11 to the refuse incinerator 5, a motor 13 for rotating the screw feeder 12, and a hopper 1.
1 and a dust-feeder weighing machine 14 that weighs the weight of the refuse received, and a lower dust level meter 15 and an upper dust level meter 16 are set in the hopper 11.

The bucket 3 is provided with a pressure detector 3a for detecting the pressure acting on the inner surface of the bucket 3 and a bucket opening detector 3b for detecting the opening of the bucket 3. As the pressure detector 3a, a metal plate or the like having a strain gauge attached to the surface can be used, and as the bucket opening detector 3b, a potentiometer or the like attached to an appropriate portion of the bucket 3 can be used.

An auxiliary fuel pipe 21, a cooling water pipe 31, and a combustion air pipe 41 are connected to the refuse incinerator 5, and each of the pipes 21, 31, 41 has a thermometer for the fluid flowing therein. 22, 32, 42 and flow meters 23, 33, 43
Is set. Further, a flue gas thermometer 52 is set at the outlet flue of the refuse incinerator 5.

Hereinafter, a general operation method of the refuse incineration facility configured as described above will be described.

The garbage collected by the garbage truck from each home or office is stored in the garbage pit 1. And
The waste stored in the waste pit 1 is taken out from the waste pit 1 by the bucket 3 attached to the supply crane 2 and sequentially supplied into the hopper 11.

The amount of dust accumulated in the hopper 11 is constantly measured by the upper and lower dust level meters 15 and 16 and the dust collector weighing machine 14, and the amount of dust accumulated in the hopper 11 is predetermined. When the value falls below the specified value, the garbage supply crane 2 is operated to move from the garbage pit 1 to the hopper 11.
Waste is supplied to It should be noted that the dust supply to the hopper 11 is automatically performed according to the output signals of the dust level meters 15 and 16 and the dust-feeder weighing machine 14, and the crane operator can visually check the dust accumulation amount in the hopper 11. It is also done by judgment. A certain amount of the waste supplied into the hopper 11 is supplied to the incinerator 5 by the screw feeder 12 installed on the bottom surface of the hopper 11.

The incinerator 5 will be described by taking a fluidized bed furnace as an example. Sand such as silica sand is used as a fluid medium, which is 650-75.
The temperature of the fluidized bed is maintained at a high temperature of about 0 ° C., and the combustion air heated by the air preheater 7 is supplied from the lower portion of the fluidized bed to perform combustion and fluidization. The dust supplied from the dust feeder 4 is agitated and mixed with the high temperature fluid medium in the fluidized bed, and is quickly dried and burned. The combustion exhaust gas 53 is discharged to the outside of the system through the combustion exhaust heat recovery device 6, the air preheater 7, and the dust removing device 8.

Next, based on FIGS. 2 and 3, the amount of heat generated by the dust is estimated from the output signals of the pressure detector 3a and the bucket opening detector 3b provided on the crane bucket 3, which is a feature of the present invention. A method of doing this and a method of correcting the heat value of waste from the heat balance around the furnace will be described.

<Method of Estimating Heat Generation Value of Waste> The waste supply crane 1 has the bucket 3 in the waste A stored in the waste pit 1 with the bucket 3 fully opened as shown in FIG. 2 (a).
And then squeezes the dust A while urging the bucket 3 from the fully opened state in the closing direction. When the dust A is scooped up, the bucket 3 is not necessarily in the fully closed state, but rather in an intermediate state between fully opened and fully closed. Next, the bucket 3 is closed to raise the bucket 3, and the bucket 3 is opened above the hopper 11 to discharge the dust.

Therefore, as shown in FIG. 2B, the pressure detector 3a acts on the inner surface of the bucket 3 when the opening of the bucket 3 reaches an appropriate opening angle α between the fully open and fully closed positions. The pressurization P ₁ is measured, and then, as shown in FIG. 2C, at the time when the opening of the bucket 3 becomes an appropriate opening angle β between the opening angle α and the full closing, the pressure detector 3 a is also set. Thus, the pressure P ₂ acting on the inner surface of the bucket 3 is measured.

K = P ₂ / P ₁ (1) K given by the above-mentioned first equation is a stress ratio when the dust is compressed, and should be regarded as a variation representing the ease of compressing the dust. You can Waste that is easy to compress has a low stress ratio K, and waste that is difficult to compress has a high stress ratio K. For example, since water is incompressible, the stress ratio K becomes large for dust having a high water content, and combustible substances such as paper and plastic have high compressibility when discharged as dust, so the stress ratio K becomes small. The bucket 3 at the time of measuring the pressurization P ₁
The reason why the opening angle α of the bucket 3 is smaller than the full opening angle is that the dust A is smaller than the rated capacity of the bucket 3 so that an appropriate pressurization can be obtained, and the bucket 3 when the pressurization P ₂ is measured. The opening angle β of is larger than the full closing angle, because the bucket 3 may not be completely closed with dust having a small compressibility.

On the other hand, the relationship between the stress ratio K of the dust and the heat value of the dust can be obtained in advance by a laboratory method. FIG.
An example of a chart showing the relationship between the stress ratio K of waste and the heat value of waste is shown in FIG. Therefore, if the stress ratio K given by the first equation is calculated from the pressurization pressures P ₁ and P ₂ acting on the inner surface of the bucket 3 and the opening angles α and β of the bucket 3 during operation of the refuse incineration facility, The heat generation amount of waste can be estimated from the chart of No. 3, and the total heat input amount can be obtained by multiplying the estimated heat generation amount by the input amount of waste. Then, the rotation speed of the screw drive motor 13 provided in the dust supply device 4 is PID-corrected so that the total heat input amount obtained in this way matches the heat amount required of the exhaust heat recovery device 6, so that it is always correct. Can maintain good combustion. Since the chart of FIG. 3 can be optimized by the method described below, it does not necessarily have to be accurate in the initial state.

Although the method for estimating the heat value of waste from the stress ratio K has been described in the above-mentioned embodiment, it is possible to measure the heat value of waste during actual operation of the waste incinerator and to obtain a correlation with the heat value of waste. If so, it is possible to estimate the heat value of waste by using other measured values. For example, the pressure with respect to the bucket opening may be continuously measured, and the differential value, that is, the slope of the line segment may be used as an index. According to the estimated waste heat generation amount, the waste supply amount is appropriately controlled so that the heat input is constant, or the waste supply amount is appropriately controlled so as to meet the heat amount required by the exhaust heat recovery device 6 that follows. You can

<Correction Method for Waste Heat Generation> Next, a method for correcting the waste heat generation amount from the heat and mass balance of the waste incinerator 5 based on FIG. 4 and correcting the chart in FIG. 3 according to the actual machine will be described. To do. In FIG. 4, the stress ratio K is calculated from the pressurization pressures P ₁ and P ₂ , and then the heat generation amount of dust is estimated from the stress ratio K and the chart of FIG. The procedure until PID correction so that the rotation speed of the drive motor 13 matches the required heat amount of the exhaust heat recovery device 6 is as described in the above section <Method of estimating waste heat generation amount>. The description is omitted to avoid duplication.

The waste conveyed in the hopper 11 by the bucket 3 is pressure-fed to the waste incinerator 5 by the screw feeder 12 provided in the dust feeder 4 and incinerated. The amount of dust accumulated in the hopper 11 is the lower dust level meter 15
Supply crane 2 when the level falls below the level set in
Waste supply to the hopper 11 by driving the
When the dust supply to the hopper 11 is stopped when the amount of dust accumulated in the hopper 11 becomes equal to or higher than the level set by the upper dust level meter 16, the dust collector 4 at the setting position of the lower dust level meter 15 Assuming that the volume is W [m ³ ] and the discharge speed of the screw feeder 12 is V [m ³ / h], the dust in the dust feeder 4 is t as shown in the second equation.
It will be incinerated after [h].

T = W / V (2) Then, the heat and mass balance around the incinerator after t [h] is as follows.

First, regarding the heat input, the sensible heat of combustion air q ₁ and the sensible heat of auxiliary fuel q ₂ expressed by the following formulas 3 to 8 are given.
, The auxiliary fuel calorific value q ₃ , the waste sensible heat q ₄ , the cooling water sensible heat q _5, and the waste calorific value q _x .

Q ₁ = W _a × i _ta (3) q ₂ = W _f × i _tf (4) q ₃ = W _f × H _f (5) q ₄ = W _x × i _tx (6) q ₅ = W _m × i _tm (7) q _x = W _x × H _x (8) where W _a [kg / h] is combustion air per hour on a weight basis. It is the flow rate, and can be obtained by measuring the volume-based air flow rate and its temperature with the flow meter 43 and the thermometer 42.

_Ita is the retained heat at the air temperature t, and since the retained heat is uniquely determined by the temperature t, it can be obtained by measuring the air temperature with the thermometer 42.

W _f [kg / h] is the weight-based flow rate of the auxiliary fuel, which can be converted from the volume-based flow rate obtained by the flow meter 23.

H _f is the calorific value of the auxiliary fuel and is uniquely determined by the fuel used.

W _m [kg / h] is a weight-based flow rate of cooling water injected when the furnace temperature rises too much, and can be measured by the flow meter 33. Further, _itm is the heat of the cooling water and can be obtained from the measurement result of the thermometer 32.

W _x [kg / h] is a waste supply amount, which is obtained by providing a weighing machine in the waste crane bucket 3 and taking a moving average of measurement data.

H _x is the heat value of the waste to be obtained here.

On the other hand, regarding heat output, combustion air dry gas possession heat Q ₁ , combustion air vapor possession heat Q _2, and furnace dissipated heat, which are represented by the following equations 9 to 11, are not accounted. Loss Q
There are _three .

Q ₁ = W _g × i _tg (9) Q ₂ = W _w × i _tw (10) Q ₃ = Q _c (11) where W _g is the dry gas in the combustion exhaust gas. It can be expressed by the following formula 12 in terms of gas weight.

W _g = W _x × (1-m) + W _f + W _a (12) W _w is the weight of water in the combustion exhaust gas and can be expressed by the following thirteenth formula.

W _w = W _x × m + W _m (13) _Itg and _itw are the heats of the dry gas and steam when the temperature of the combustion exhaust gas is t, and the heats of each are the temperature t. It can be determined by measuring the combustion exhaust gas temperature with the thermometer 52.

Further, m is the water content of the waste, which is difficult to measure in real time, but as described above, the waste with a high water content is close to incompressibility and the stress ratio k is high, and the water content containing a large amount of combustible substances. Since the stress ratio K is small for less dust, it can be obtained from the correlation {m = f (k)} with the stress ratio K.

Q _c is an uncounted loss, which is the amount of heat dissipated from the wall surface of the furnace, but since it accounts for a small proportion of the total heat input and output, it can be calculated as an appropriate constant.

By rearranging the third to eleventh equations described above with the property that the heat input / output is equal, the following fourteenth equation and fifteenth equation are obtained, and the sixteenth equation is obtained from each of these equations.

Q = q ₁ + q ₂ + q ₃ + q ₄ + q ₅ + q _x (14) Q = Q ₁ + Q ₂ + Q ₃ (15) q _x = Q- (q ₁ + q ₂ + q ₃ + q ₄ ) = W _x × H _x (16) By solving this 16th equation, the heat value H _x of waste heat can be obtained. The correlation equation of FIG. 3 may be corrected by the heat generation amount H _{x of} dust thus obtained and the stress ratio K corresponding thereto.

[0046]

As described above, according to the present invention,
A pressure detector and a bucket opening detector are installed in the bucket of the garbage supply crane, and the output value of the pressure detector when the bucket opening is large and the output value of the pressure detector when the bucket opening is narrowed The size of the stress ratio of the waste caught in the bucket is calculated from the above, and the heat generation amount of the waste is estimated from the correlation equation between the stress ratio of the waste and the heat generation amount of the waste that is obtained in advance. It is possible to accurately estimate the calorific value of the waste thrown into the furnace and easily determine whether the increase or decrease in the furnace temperature is due to the increase or decrease in the supplied amount of the waste or the fluctuation in the calorific value of the waste. Therefore,
The waste supply amount can be appropriately controlled so that the heat input is constant, or the waste supply amount can be appropriately controlled so as to match the heat amount required by the subsequent exhaust heat recovery device.
Further, since the heat generation amount of waste is obtained from the actual incineration result by the heat and mass balance and the relational expression with the stress ratio is corrected, it is possible to always accurately estimate the heat generation amount of waste.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refuse incineration facility according to the present invention.

FIG. 2 is a side view showing a configuration of a bucket according to the present invention and a dust stress ratio measuring method by the bucket.

FIG. 3 is a graph showing a relationship between a stress ratio K of waste and a heat value of waste.

FIG. 4 is a control characteristic diagram of the refuse incineration facility according to the present invention.

[Explanation of symbols]

 1 Garbage Pit 2 Garbage Supply Crane 3 Crane Bucket 3a Pressure Detector 3b Bucket Opening Detector 4 Dust Incinerator 5 Waste Incinerator 6 Exhaust Heat Recovery Device 7 Air Preheater 8 Dust Removal Device 11 Hopper 12 Screw Feeder 13 Screw Drive Motor 14 Dust supply equipment Heavy equipment 15 Lower dust level meter 16 Upper dust level meter 21 Auxiliary fuel piping 31 Cooling water piping 41 Combustion air piping 22, 32, 42, 52 Thermometer 23, 33, 43 Flowmeter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F23G 5/00 108 F23G 5/00 108B

Claims (2)

[Claims] 1. In a refuse incineration facility for supplying refuse into an incinerator using a refuse supply crane, a pressure detection device is installed on the inner surface of the bucket of the refuse supply crane, and the pressure relative to the opening degree of the bucket when the refuse is caught. A method for operating a refuse incineration facility, which comprises estimating a waste heat generation amount from a correlation equation between a change amount of a detection device indicated value and a waste heat generation amount obtained in advance, and controlling the waste heat supply amount. 2. The calorific value of the refuse during combustion is calculated back from the flow and temperature of the air, auxiliary fuel and cooling water added to the refuse incinerator, the temperature of the combustion exhaust gas, the amount of heat dissipated, etc. according to claim 1. The operation of the waste incineration facility is characterized in that the heat value of the waste is controlled by estimating the heat value of the waste while correcting the correlation of the change amount of the indicated value of the pressure detection device and the heat generation amount using this as a correction value. Method.