JP3309657B2 - Waste gasification and melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention is to form a deposited layer by the charged waste and a carbon-based auxiliary fuel such as coke, and to blow an oxygen-containing gas to thermally decompose the waste and to remove ash and incombustibles in the waste. Waste gasification melting to be melted
About the furnace .

[0002]

2. Description of the Related Art The prior art relating to the waste gasification and melting furnace and the gasification and melting method is disclosed in Japanese Unexamined Patent Publication No.
There is one disclosed in Japanese Patent Application Laid-open No. 1 (Kokai). In this technique, as shown in FIG.
Is provided, and an oxygen-containing gas is blown from the tuyere 43. In the figure, 41 is a waste charging device, 42 is a discharge port of the melt, 44 is an oxygen-containing gas supply pipe, and 45 is an exhaust gas discharge port.

[0003] When waste is gasified and melted by this technique, oxygen-containing gas is blown from a tuyere 43 provided at a lower portion of the furnace main body 40, so that waste and auxiliary materials charged from an upper portion of the furnace main body 40 are blown. The fuel and the like are partially fluidized, and a part of the waste is burned during the fluidization. Then, the waste heat is thermally decomposed by the heat of combustion,
Melts ash and incombustibles in waste.

At this time, the gas temperature of the free board is set to 95
If the temperature is not maintained in a high temperature range of 0 ° C. or higher, dioxin is generated. If the gas temperature is 1000 ° C. or less, the tar generated by the thermal decomposition is discharged without being decomposed, and a part of the tar adheres to a duct or the like in a gas discharge path, and the adhered tar is recovered. And the adhesion of dust is promoted. When the amount of deposits becomes large, the duct is closed, and the furnace must be stopped to carry out the operation of removing the deposits.

For this reason, by controlling the flow rate of the oxygen-containing gas blown from the tuyere 43, the gas temperature in the freeboard portion is controlled to be maintained at a predetermined high temperature range, the generation of dioxin is suppressed, and the generated tar Is in a condition to be decomposed.

[0006]

However, in the above prior art, the gas temperature of the freeboard section is controlled by adjusting the flow rate of the oxygen-containing gas blown from the tuyere 43 provided in the lower part of the furnace body. And controls the fluidization of the sedimentary layer consisting of waste and auxiliary fuel, and the control of melting of ash and incombustibles in the waste at the furnace bottom. Since the amount must be adjusted, there are the following problems.

To control the gas temperature of the freeboard section by adjusting the flow rate of the oxygen-containing gas blown from the tuyere 43 provided at the lower part of the furnace body, the amount of the oxygen-containing gas blown is reduced by the freeboard. The flow rate value must satisfy both the conditions for maintaining the gas temperature of the part and the conditions for melting ash, etc., but the flow rate value that satisfies both conditions is limited to a very narrow range. Therefore, if the properties of the waste to be treated change or the amount of treatment changes even slightly, a problem often arises in that ash or the like cannot be melted in an appropriate state.

The present inventors have solved the above-mentioned problems and developed a technique for controlling the gas temperature in the freeboard section and controlling the melting of ash and the like in the furnace bottom by different means. Earlier, they filed two patent applications related to these technologies.

[0009] Of the above techniques, Japanese Patent Application No. 6-227059.
In the technique of No. 1 (hereinafter referred to as the prior application A), as shown in FIG. 3, a tuyere 5 for blowing an oxygen-containing gas is provided at a lower portion of the furnace main body 1, and the charged waste is charged. The tuyere 3 is also provided at a level corresponding to a level above the upper surface of the deposition layer 50 formed by the carbon-based auxiliary fuel.

For this reason, in the prior application A, the roles of the respective tuyeres are shared, and by adjusting the flow rate of the oxygen-containing gas blown from the lower tuyeres 5, the deposition layer 50 is partially formed. While flowing, control is performed to improve the melting state of the ash and the non-combustible portion, and the flow rate of the oxygen-containing gas blown from the tuyere 3 provided at a level higher than the upper surface of the deposition layer 50 is adjusted. By doing so, the gas temperature of the free board section is controlled.

In the figure, 1a is a free board section, 2 is a loading port for waste and carbon-based auxiliary fuel, 6 is a discharge port for molten material,
Reference numeral 7 denotes a discharge port of the combustion exhaust gas, 8 denotes a thermometer, 9 denotes a gas analyzer, 17 denotes an air flow control valve, and 19 denotes an oxygen flow control valve.

Further, Japanese Patent Application No. 6-227060 (hereinafter referred to as "Japanese Patent Application No.
The technique of the prior application B) is, as shown in FIG.
In addition to the tuyere 5 for blowing oxygen-containing gas at the lower part of the stack, the tuyere 4 is also provided in a portion where the waste below the upper surface of the sedimentary layer 50 is still being carbonized (the carbonization zone). I have. 4, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

In the prior application B as well, the respective tuyeres are assigned a role, and the flow rate of the oxygen-containing gas blown from the lower tuyere 5 is adjusted so that the deposited layer 50 is partially flown. In order to improve the melting state of the ash and the non-combustible portion, the upper portion of the deposition layer 50 is appropriately adjusted by adjusting the flow rate of the oxygen-containing gas blown from the tuyere 4 provided in the carbonization zone. The gas temperature in the freeboard section is controlled while the gas flows in the freeboard section.

In the prior application B, since the oxygen-containing gas is blown into the carbonization zone, volatiles generated in the process of carbonizing the waste burn. Further, since the combustion heat is used as a part of a heat source for melting ash and incombustibles, the effect of saving the carbon-based auxiliary fuel to be charged together with the waste can be obtained.

As described above, in the earlier application A or the earlier application B, the tuyere for blowing the oxygen-containing gas is provided at two places, and the control relating to the melting of the ash and the non-combustible content and the free board portion Since each gas temperature is controlled independently,
It has become possible to control the gas temperature of the freeboard while maintaining the molten state of ash and incombustibles at the furnace bottom in an appropriate state.

However, further examination of the technologies of the prior application A and the prior application B revealed that there is still room for improvement.

That is, in the prior application A, the flow rate of the oxygen-containing gas blown from both the lower tuyere 5 and the tuyere 3 provided above the upper surface of the deposition layer 50 is adjusted, so that the deposition is performed. While gently flowing the layer 50, control relating to melting of ash and non-combustible and control of the gas temperature of the freeboard portion are performed.
Although the gas temperature of the freeboard section can be maintained in a predetermined high temperature range, the flow state of the deposition layer 50 cannot be maintained in an appropriate state depending on the type and amount of waste.

If the flow of the deposition layer 50 becomes insufficient, a deviated gas flow path is formed in the deposition layer 50, and the flow of the blown oxygen-containing gas tends to occur. In such a state, an abnormally high temperature portion is generated in the deposition layer 50, and clinker is generated at that portion. Then, there arises a problem that the accumulation layer 50 is suspended from the shelf and does not descend, resulting in an abnormal operation.

In the prior application B, the flow rate of the oxygen-containing gas blown from the tuyere 4 in the carbonization zone is adjusted.
Although it is possible to improve the flow state of the sedimentary layer 50, depending on the type of waste and the amount of treatment, simply blowing an oxygen-containing gas at a flow rate sufficient to improve the flow state of the sedimentary layer 50 can be achieved. 1000 ° C gas temperature at free board
It is difficult to raise the temperature above. If a large amount of oxygen-containing gas is blown from the tuyere 4 of the carbonization zone to raise the gas temperature of the freeboard portion, the flow of the sedimentary layer 50 becomes too violent, and a large amount of dust is generated. The problem arises that the device must be large.

The present invention solves the above-mentioned problems of the prior art and also solves the problems of the prior application A and the prior application B, while maintaining the molten state of ash and the like in the lower part of the furnace body in a good state. In addition, the flow of the deposited layer can be maintained in a good state, and the gas temperature of the
Waste gasification and melting that can be maintained in the high temperature range above ℃
It is intended to provide a melting furnace .

[0021]

According to a first aspect of the present invention, there is provided a waste gasification / melting furnace having an inlet for waste and a carbon-based auxiliary fuel at an upper portion of a furnace body provided with a free board portion. A vertical furnace that has a tuyere that blows oxygen-containing gas into the side of the furnace body, pyrolyzes the loaded waste to generate flammable gas, and melts ash and incombustibles in the waste. Waste and carbon-based subsidies
Level corresponding to the lower part of the deposit formed by the fuel
And the lower tuyere that blows the oxygen-containing gas
Has a mechanism to adjust the flow rate of oxygen-containing gas to be supplied to the tuyere
And an oxygen-containing layer provided at a level corresponding to the upper part of the deposition layer.
Supply of gas to the middle tuyere and the middle tuyere
A mechanism for adjusting a flow rate of the oxygen-containing gas, wherein the deposition layer
Oxygen-containing gas provided at a level above the upper surface of
With the upper tuyere that blows air from the upper tuyere
Air piping and acid provided for preparing oxygen-containing gas
The raw pipe and the gas thermometer and
And gas analyzer and the thermometer and gas analyzer
Based on the measured gas temperature and gas analysis values.
Regulate the flow of air and / or oxygen to the mouth
Controls the temperature and calorific value of the flue gas, which
It has a mechanism for adjusting .

In addition, charging of waste and carbon-based auxiliary fuel
The upper part of the furnace body where the port is provided refers to the upper part of the furnace body.
And necessarily means the top of the furnace body.
Not .

Therefore, the place where the above-mentioned charging port is provided is free.
It may be the side surface of the board part .

According to the invention, it is also possible to change the shape by the charge.
Because the upper part of the formed sedimentary layer flows slowly,
Is the area where the charge is flowing slowly
Minutes .

The upper surface of the deposition layer is flowing.
It shall refer to the upper surface of the part .

In the waste gasification and melting furnace according to the first aspect of the present invention, the level corresponding to the level above the upper surface of the deposited layer formed by the charged waste and the carbon-based auxiliary fuel, The upper tuyere, the middle tuyere, and the lower tuyere are provided at the level corresponding to the upper part (the dry distillation zone) and the level corresponding to the lower part of the sedimentary layer, respectively. By adjusting the flow rate of the oxygen-containing gas blown from the tuyere, it is possible to individually control the gas temperature of the freeboard section, the flow state of the upper part of the sedimentary layer, and the melting state of ash at the lower part of the furnace body, respectively. The operation can be continued with each part in the furnace being in an appropriate state.

The gas blown into the above three tuyeres
Since the amount can be adjusted individually, the flow rate of air and / or oxygen supplied to the upper tuyere can be adjusted as necessary while maintaining The amount of oxygen to be blown can be appropriately changed. For this reason, the amount of combustible gas burned in the free board portion becomes appropriate, and the gas temperature can be maintained in a temperature range of 1000 ° C. or higher where tar is decomposed and dioxin is not generated.

Also, if necessary, the flow rate of air and / or oxygen supplied to the upper tuyere can be adjusted to appropriately change the oxygen concentration in the gas blown from the upper tuyere. Therefore, the composition of the gas in the freeboard portion generated by the combustion of the combustible gas can be changed, and the calorific value of the gas can be maintained at a predetermined value or more.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a configuration diagram showing one embodiment of a waste gasification and melting furnace according to the present invention. Reference numeral 1 denotes a vertical furnace body, and the furnace body 1 is constituted by a cylindrical freeboard section 1a located at an upper portion thereof, a bosh section 1b whose diameter is increased upward, and a furnace bottom section 1c. I have. An inlet 2 for combustible waste and carbon-based auxiliary fuel is provided at the top of the furnace main body 1, and a tuyere for blowing oxygen-containing gas is provided at a side of the furnace main body 1. A plurality of tuyeres are provided as a set on the circumference of three levels along the height direction of the furnace body 1. The tuyere set is provided at a level corresponding to a level above the upper surface of the deposition layer 50 formed by the carbon-based auxiliary fuel such as waste and coke (a space above the upper surface of the deposition layer 50). The upper tuyere 3 is a tuyere 3 and the other tuyere is a middle tuyere 4 provided at a level corresponding to the upper part of the deposition layer 50 (200 mm to 2000 mm below the upper surface of the deposition layer 50). Another set of tuyeres is the lower tuyeres 5 provided at the level corresponding to the lower part of the deposition layer 50. In the figure, 6 is an outlet for the melt, 7 is an outlet for the flue gas, 8 is a thermometer for measuring the temperature of the flue gas, 9 is an analyzer for the flue gas, 10, 11
Is a heat exchanger.

In FIG. 1, the charging port 2 for the waste and the carbon-based auxiliary fuel is provided at the top of the furnace body 1, but the location where the charging port 2 is provided is not limited to the top. . The position of the loading port 2 may be above the bosh section 1b, and may be on the side of the freeboard section 1a.

With the gasification and melting furnace having the above configuration,
When gasifying and melting waste, first, waste and coke, one of the carbon-based auxiliary fuels, a slag conditioner, and the like are charged from the charging inlet 2, and a deposited layer 50 is formed by these charged materials. Is done. The charge forming the deposition layer 50 is appropriately flowed by air blown from the tuyere 4 at the middle stage to which the pipe 15 is connected, and a part of the charge flows together with the combustible gas generated in the lower part. Burns. By this heat of combustion, the waste is heated and carbonized,
Combustible gas is generated.

The temperature of the air blown from the tuyere 4 is preferably from room temperature to about 100 ° C. When the heated air is blown, the air that has been heated by exchanging heat with the combustion exhaust gas in the heat exchanger 10 is supplied via a pipe 12 (a supply pipe in this case is not shown).

It is preferable that the amount of air blow is such that the deposited layer 50 flows appropriately together with the gas rising from the bottom. Tower speed is 0.3 to 1.4 Nm / sec
(Gas flow rate in standard condition conversion) is preferable.

The charge that has been carbonized falls down sequentially from the upper part of the sedimentary layer 50 to the furnace bottom, and after the residual carbon is burned by the oxygen-containing gas blown from the tuyere 5 at the lower stage, it is incinerated. , And is withdrawn from the melt outlet 6.

The air for preparing the oxygen-containing gas blown from the tuyere 5 at the lower stage is heated by exchanging heat with the combustion exhaust gas, and is supplied from the pipe 13 via the heat exchanger 11.

The oxygen-containing gas is a mixture of high-temperature air and oxygen. The higher the temperature, the better. However, as described above, the supplied air is heated by heat exchange with the combustion exhaust gas. Therefore, the oxygen-containing gas is usually blown at a temperature of about 100 ° C. to 500 ° C. The oxygen concentration is usually 30% or more, and is adjusted so that the high-temperature region formed near the tuyere portion 5 in the furnace becomes 2000 ° C. or more.

The blowing of the oxygen-containing gas from the lower tuyere 5 is performed to melt the ash and incombustibles of the waste while gently flowing the upper part of the sedimentary layer 50. The range satisfies the following equation (1).

[0038]

(Equation 1)

On the other hand, the generated combustible gas is partially burned by the oxygen-containing gas blown from the upper tuyere 3 in the freeboard section 1a, and the temperature of the combustible gas is prevented from lowering. At this time, if the flow rate of air and oxygen supplied to the upper tuyere 3 or the flow rate of either air or oxygen is adjusted and the amount of oxygen blown from the tuyere 3 is adjusted, the combustion amount can be appropriately changed. Therefore, the gas temperature of the free board section 1a can be maintained in a predetermined range. In this way, in the free board portion 1a, dioxin is not generated, and tar is decomposed and disappears.
The above temperature is maintained. However, if the gas temperature becomes too high, the refractory deteriorates quickly and there is a problem that ash (dust) is fused to the furnace wall. Therefore, the upper limit of the temperature is desirably set to about 1200 ° C.

If the flow rate of air and oxygen supplied to the upper tuyere 3 or the flow rate of either air or oxygen is adjusted to adjust the oxygen concentration in the gas blown from the tuyere 3, the free board section Since the composition of the combustible gas generated in the step (1) can be changed, the calorific value of the combustion exhaust gas can also be controlled.

The oxygen-containing gas blown from the upper tuyere 3 may be air alone, but if it is desired to obtain combustion exhaust gas having a high calorific value, a mixed gas of air and oxygen is preferable. .

The temperature of the oxygen-containing gas blown from the upper tuyere 3 may be room temperature, but it is blown to maintain the gas temperature in the free board section 1a at a high temperature. The higher the temperature, the better. For this reason, the air for preparing the oxygen-containing gas blown from the upper tuyere 3 is heated by exchanging heat with the combustion exhaust gas, and is supplied from the pipe 14 via the heat exchanger 10.

The calorific value of the gas is 1000 kcal / Nm ³ -12
It is preferable to control the pressure in the range of about 00 kcal / Nm ³ . The range of the calorific value was determined based on the following. 1000kcal / Nm when used for gas turbine fuel
It is necessary to have a calorific value of ³ or more, and it is desirable that the calorific value of the gas be as high as possible. However, the calorific value of the gas obtained when the consumption of expensive oxygen is suppressed as small as possible is 1200 kcal / Nm. ^By about ³ .

When the gas temperature in the free board section 1a is to be maintained within a predetermined range and the calorific value of the gas is to be maintained within a predetermined range, the flow rates of air and oxygen must satisfy the above two conditions. Must be set to a value that allows The supply flow rates of the air and oxygen vary depending on the type of waste to be charged. For example, shredder dust (combustible after crushing waste of automobiles and home appliances and collecting valuable resources) In the case of waste or municipal waste, the flow rate is adjusted based on the criteria in Table 1. Table 1 shows that the gas temperature is maintained at 1000 ° C. to 1200 ° C. and the calorific value of the gas is 1000 kcal / Nm ^{3 to} 1200 kcal.
/ Nm ³ is a flow control standard for maintaining the flow rate, and a part thereof is as follows.

If the gas temperature is lower than 1000 ° C. and the calorific value of the gas is lower than 1000 kcal / Nm ³ and the two measured values do not satisfy the operation standards, the flow rate of oxygen is increased. When the gas temperature is higher than 1200 ° C. and the calorific value of the gas is higher than 1200 kcal / Nm ³ ,
First, the flow rate of oxygen is reduced. Next, even if the supply of oxygen is stopped, if the value does not reach a normal value, the flow rate of air is also reduced.

[0046]

[Table 1]

The flue gas whose temperature has been maintained at 1000 ° C. or higher is retained in the freeboard section 1a for several seconds and then discharged from the flue gas discharge port 7. And the heat exchanger 10,
After passing through 11 and being cooled by heat exchange with the air blown into the furnace, it is sent to an exhaust gas treatment device 30 that performs processing such as dust removal. The treated combustion exhaust gas is stored in the gas holder 31 and is used for applications such as fuel gas for driving a gas turbine for power generation.

In the process of discharging the combustion exhaust gas as described above, the gas temperature is measured by the thermometer 8 and the gas is analyzed by the gas analyzer 9. The measured value of the gas temperature is sent to the control mechanism, and is used as data for controlling the gas temperature by adjusting the flow rate of air or oxygen supplied to the upper tuyere 3. The gas analysis value is sent to the control mechanism and converted into a calorific value.
It is used as data for controlling the calorific value of gas by adjusting the flow rate of air or oxygen supplied to 3.

In FIG. 1, reference numeral 17 denotes an air flow control valve for adjusting the oxygen-containing gas blown from the upper tuyere 3;
Is an oxygen pipe, 19 is an oxygen flow control valve for preparing an oxygen-containing gas blown from the upper tuyere 3, 20 is a flow control valve for air blown from the middle tuyere 4, and 21 is a lower flow tuyere. An air flow control valve for adjusting the oxygen-containing gas to be blown in, 22 is an oxygen pipe, and 23 is an oxygen flow control valve for adjusting the oxygen-containing gas to be blown from the lower tuyere 5.

[0050]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The results of gasification and melting treatment of waste using a test apparatus having the same configuration as that of FIG. 1 will be described. The waste charged in this test was shredder dust.

In this test, the tuyere 3 in the middle stage and the tuyere 5 in the lower stage were used without using the tuyere 3 in the upper stage.
The flow rate of air blown into the deposition layer 50 from the tuyere 4 at the middle stage was varied and gasified and melted, and various measurements and operating conditions were checked during that time. In this case, the air is blown from the tuyere 4 in the middle stage in a stepwise manner so that the superficial velocity of the gas in the section A-A shown in FIG. 2 becomes 0.08 Nm / sec to 1.6 Nm / sec. Was changed to. In addition,
Since the configuration of the apparatus in FIG. 2 is the same as that in FIG. 1, the same reference numerals are given and the description thereof is omitted.

First, among the various measurements, the result of measuring the dust concentration in the combustion exhaust gas was as shown in FIG. As shown in FIG. 5, the dust concentration in the combustion exhaust gas increases as the superficial velocity (air blowing flow rate) increases.
The dust concentration is abruptly increased at the vicinity of the superficial velocity is more than 1.4 Nm / sec, the value is to exceed 10 g / Nm ^3. According to this result, the flow rate of the air blown from the tuyere 4 in the middle stage needs to be such that the superficial velocity is 1.4 Nm / sec or less.

When the flow rate of air from the tuyere 4 in the middle stage was adjusted so that the gas temperature of the freeboard 1a became 1000 ° C. or more, the superficial velocity became 1.4 Nm / sec or more, and the Contained a large amount of dust. From this, the gas temperature of the freeboard 1a was set to 1000 ° C. by adjusting the flow rate of the air blown from the tuyere 4 in the middle stage.
It has proven difficult to maintain above.

FIG. 6 shows the relationship between the flow rate of the air blown from the tuyere 4 at the middle stage and the slag conversion ratio. The slag conversion rate is the ratio of the amount of molten slag extracted to the total amount of ash and incombustibles contained in the waste, coke, slag conditioner, etc. This is a value obtained by the following (2).

[0055]

(Equation 2)

As shown in FIG. 6, when the superficial velocity is increased, the slag conversion rate is reduced, and when the superficial velocity exceeds 1.4 Nm / sec, the slag conversion rate is reduced to 90% or less. This means that as the superficial velocity increases, the waste becomes finer and the amount of dust scattered significantly increases. According to this result, the flow rate of the air blown from the tuyere 4 in the middle stage needs to be such that the superficial velocity is 1.4 Nm / sec or less.

Further, the relationship between the flow rate of air blown from the tuyere 4 in the middle stage and the situation in which the shelves of the deposited layer 50 are suspended was examined, and the result was as shown in FIG. As shown in FIG.
If the superficial tower speed becomes 0.3 Nm / sec or less, shelves will be hung and an abnormal state will occur. According to this result,
The flow rate of the air blown from the tuyere 4 at the middle stage must be such that the superficial velocity exceeds 0.3 Nm / sec.

When the air flow to be blown from the tuyere 4 is determined from the above three measurements or the record of the operating state, FIG.
According to the measurement results of the dust scattering shown in FIG. 6 and the slag conversion rate shown in FIG. 6, the superficial velocity is within the range of 1.4 Nm / sec or less, and according to the result of the shelf hanging state shown in FIG. , And the superficial velocity exceeds 0.3 Nm / sec. Therefore,
Desirable value of the air flow rate is 0.3 Nm / sec to 1.4.
The range is about Nm / sec.

Next, the concentration of dioxins and the concentration of tar in the combustion exhaust gas when the gas temperature of the freeboard section 1a was changed were measured. FIG. 8 shows the relationship between the gas temperature of the free board and the concentration of dioxins, and FIG.
Indicates the relationship between the gas temperature of the free board portion and the concentration of tar.

According to FIG. 8, when the gas temperature in the free board portion becomes 950 ° C. or higher, the concentration of dioxins represented by the toxic equivalent concentration (ratio with the allowable value) tends to decrease significantly. Above 1000 ° C, the toxic equivalent concentration falls below the permissible value.

According to FIG. 9, when the gas temperature of the free board is raised to 1000 ° C. or more, the concentration of tar falls below the allowable value (the limit value at which no adhesion trouble occurs).

[0062]

When the waste gasification and melting furnace according to the first aspect of the present invention is used, the level corresponding to the level above the upper surface of the deposition layer formed by the charge and the level corresponding to the upper portion of the deposition layer. The upper and middle tuyeres and the lower tuyeres are provided at the level and the level corresponding to the lower part of the sedimentary layer, respectively, so that the molten state such as ash at the lower part of the furnace body is maintained in a good state. Meanwhile, the flow of the sedimentary layer can be maintained in a favorable state, and the gas temperature of the freeboard portion can be maintained in a high temperature range of 1000 ° C. or higher, and stable operation can be continued.

[0063]

[0064]

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a waste gasification and melting furnace according to the present invention.

FIG. 2 is a diagram showing a furnace main body of the waste gasification and melting furnace according to the present invention.

FIG. 3 is a diagram showing a configuration of a waste gasification and melting furnace in which tuyeres are provided at a lower level of a furnace main body and at a level above an upper surface of a deposition layer.

FIG. 4 is a diagram showing a configuration of a waste gasification and melting furnace in which tuyeres are provided at a lower level of a furnace main body and at a level of an upper portion of a deposition layer.

FIG. 5 is a diagram showing a relationship between a superficial velocity of air blown from a tuyere at a middle stage and a dust concentration in combustion exhaust gas.

FIG. 6 is a diagram showing the relationship between the superficial velocity of air blown from the tuyere of the middle stage and the slag conversion rate.

FIG. 7 is a diagram showing the relationship between the superficial velocity of air blown from the tuyere in the middle stage and the number of times the piles are suspended from the shelves.

FIG. 8 is a diagram showing the relationship between the gas temperature of the freeboard section and the concentration of dioxins (toxic equivalent concentration).

FIG. 9 is a diagram showing the relationship between the gas temperature of the free board portion and the concentration of tar.

FIG. 10 is a diagram showing a configuration of a waste gasification and melting furnace according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace main body 2 Inlet for waste and carbon-based auxiliary fuel 3 Upper tuyere 4 Middle tuyere 5 Lower tuyere 6 Melt outlet 7 Combustion exhaust gas outlet 8 Thermometer 9 Gas analyzer 10, Reference Signs List 11 heat exchanger 17 air flow control valve to be supplied to upper tuyere 19 oxygen flow control valve to be supplied to upper tuyere 20 air flow control valve to be supplied to middle tuyere 21 supply to lower tuyere Flow control valve for air to be supplied 23 Flow control valve for oxygen supplied to lower tuyere

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F23G 5/50 ZAB F23G 5/50 ZABF ZABG ZABH F23L 7/00 F23L 7/00 A (72) Inventor Yuichi Yamakawa Chiyoda-ku, Tokyo 1-2-1 Marunouchi Nippon Kokan Co., Ltd. (72) Inventor Takeshi Furukawa 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yotaro Ohno 1-1-1 Marunouchi, Chiyoda-ku, Tokyo No. 2 Nippon Kokan Co., Ltd. (56) References JP-A-56-108018 (JP, A) JP-A-6-129618 (JP, A) JP-A-1-184314 (JP, A) JP-A-5 −346221 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23G 5/00 F23G 5/027 F23G 5/24 F23G 5/50 F23L 7/00

Claims (1)

(57) [Claims] 1. A furnace having an inlet for waste and carbon-based auxiliary fuel at an upper part of a furnace body provided with a free board part, and a tuyere for blowing an oxygen-containing gas into a side of the furnace body.
This is a vertical furnace that pyrolyzes the charged waste to generate flammable gas and melts the ash and incombustibles in the waste, formed by the charged waste and carbon-based auxiliary fuel. Sa
Oxygen-containing gas at a level corresponding to the bottom of the
And the oxygen supplied to the lower tuyere
A mechanism for adjusting the flow rate of the contained gas,
While blowing oxygen-containing gas at the level corresponding to the
Tuyere tuyere and flow rate of oxygen-containing gas to be supplied to the middle tuyere
A mechanism to adjust the phase, and adjust the phase above the top surface of the deposition layer.
Upper wing that blows oxygen-containing gas at the appropriate level
Prepares oxygen-containing gas that has a mouth and is blown from the upper tuyere
Air piping and oxygen piping
Gas thermometer and gas analyzer provided at the top of the
Gas temperature measured by this thermometer and gas analyzer
Air and air supplied to the upper tuyere based on the
And / or control means for adjusting the flow rate of oxygen
A waste gasification / melting furnace having a mechanism for adjusting the temperature and calorific value of combustion exhaust gas.