JP2004316956A - Fluidized bed type gasification melting furnace device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasification melting furnace device for individually optimally holding the temperature of a gasification furnace and a melting furnace to a change in garbage quality. <P>SOLUTION: This fluidized bed type gasification melting furnace device has a fluidized bed type gasification furnace 5 for pyrolyzing and gasifying garbage, and the melting furnace 13 for burning combustible gas and combustible particulates generated by pyrolysis of the garbage at the high temperature; and variably adjusts the supply ratio of auxiliary fuel quantity and auxiliary air quantity by supplying auxiliary fuel 9 and auxiliary air 11 to the gasification furnace 5. An auxiliary fuel input port for supplying the auxiliary fuel to the gasification furnace is arranged in a space part of a fluidized bed upper part or a fluidized bed; and supplies the auxiliary air supplied to the gasification furnace in the fluidized bed by adding to fluidizing air to the space part or a diffuser pipe of the fluidized bed upper part. An auxiliary fuel flow rate to the gasification furnace is adjusted on the basis of the melting furnace temperature by detecting the temperature 14 of the melting furnace. The auxiliary air quantity is adjusted on the basis of the fluidized bed temperature by detecting the fluidized bed temperature 8 of the gasification furnace. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluidized-bed waste gasification / melting / combustion facility, and more particularly to a gasification / melting furnace apparatus suitable for maintaining the temperatures of a gasification furnace and a melting furnace within a certain range even if the quality of waste fluctuates.
[0002]
[Prior art]
As a general prior art, a fluidized bed gasification and melting furnace separates and generates non-combustible components, valuable metals from combustible gas, and char components by pyrolyzing waste such as household waste in the gasifier, resulting in combustible combustion. Only gas and char are burned at high temperature in a rotary melting furnace. As a result, the generation of dioxin is suppressed by high-temperature combustion, and the combustion ash is an environmentally friendly incineration system that can reduce the volume of molten slag.
[0003]
Here, in order to thermally decompose the refuse, the gasification furnace is operated at a fluidized bed temperature of 500 to 700 ° C. as a low air ratio atmosphere having an air ratio of 1.0 or less. In the melting furnace, high-temperature combustion at a temperature higher than the melting point of the incinerated ash (generally, 1300 ° C. or higher) is performed under an air ratio of about 1.0. In order to perform a stable gasification and melting operation, it is important to control the temperature and the air ratio of the gasification furnace and the melting furnace.
[0004]
On the other hand, the quality of waste, such as the amount of moisture and calorific value of the waste, varies greatly depending on the type and season of the waste. As a result, an event occurs in which the temperatures of the gasification furnace and the melting furnace decrease.
[0005]
Even in the waste incinerator of the related art, when the waste quality is reduced, an event occurs in which the temperature of the fluidized bed, which is the combustion site, decreases. In this case, in order to maintain stable combustion, a method of maintaining a combustion temperature by supplying an auxiliary fuel in an amount capable of generating a heat value corresponding to a decrease in waste quality to an incinerator and burning the fuel is generally used. Is being done. In this method, the amount of air supplied to the refuse incinerator is set sufficiently high to about 1.5 to 1.8 with respect to the theoretical air amount of the refuse, so that the auxiliary fuel supplied to the refuse incinerator is incinerated. It burns in the furnace and performs the function or function of raising the temperature of the refuse incinerator.
[0006]
Therefore, in the gasification and melting furnace, it has been proposed to adjust the melting furnace temperature of the high-temperature combustion section by supplying the auxiliary fuel to the gasification furnace by diverting the above-mentioned conventional waste incineration method as it is. (For example, see Patent Document 1).
[0007]
[Patent Document 1]
JP-A-9-236220
[Problems to be solved by the invention]
In the above-mentioned conventional incinerator or gasification and melting furnace, the feature is that the temperature of the combustion section is adjusted with an auxiliary fuel in any case. Since a gasifier exists upstream of the gas flow of a certain melting furnace, the temperature of the two furnaces (gasification furnace and melting furnace) can be controlled by a single operating means using only auxiliary fuel, similar to the waste incinerator of the prior art. It is difficult to control individually.
[0009]
Furthermore, in the gasification and melting furnaces, it is difficult to maintain the optimum temperatures of the gasification and melting furnaces only by adjusting the supply amount of the auxiliary fuel based on various test research and analysis and evaluation. It was found from the result of elucidation of the test data. For example, when the waste quality is reduced and the water content is increased or the calorific value is reduced, the temperatures of the gasifier and the melting furnace downstream of the gasifier both tend to decrease. In this state, if the amount of auxiliary fuel corresponding to the amount of heat required to maintain the temperature of the melting furnace is supplied to the gasifier, the sensible heat of the auxiliary fuel and the heat of vaporization (auxiliary fuel Is consumed from the heat of the gasifier, the temperature of the gasifier tends to further decrease. Due to the decrease in the temperature of the gasification furnace, the generation of pyrolysis gas is suppressed, and the temperature of the melting furnace may not be improved despite the supply of the auxiliary fuel, or may tend to decrease.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a gasification and melting furnace apparatus capable of simultaneously and optimally maintaining the temperatures of a gasification furnace and a melting furnace with respect to a change in waste.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention mainly employs the following configuration.
In a fluidized bed gasification and melting furnace device comprising: a fluidized bed gasifier for pyrolyzing and gasifying refuse; and a melting furnace for burning flammable gas and flammable particles generated by pyrolysis of refuse at a high temperature. ,
An auxiliary fuel and auxiliary air are supplied to the gasification furnace.
[0012]
In the fluidized-bed gasification and melting furnace apparatus, an auxiliary fuel inlet for supplying the gasification furnace is provided in a space above the fluidized bed or in the fluidized bed, and auxiliary air supplied to the gasification furnace is supplied on the fluidized bed. The fluidized air to be supplied to the fluidized bed is added to the fluidized air to the space portion of the section or the air diffuser.
[0013]
Further, in the fluidized bed gasification and melting furnace device, the temperature of the melting furnace is detected, and the auxiliary fuel flow rate is adjusted based on the detected temperature.
The fluidized bed temperature of the gasification furnace is detected, and the auxiliary air amount is adjusted based on the detected fluidized bed temperature.
[0014]
Further, in the fluidized bed gasification and melting furnace device, the temperature of the melting furnace is detected, and the auxiliary fuel flow rate is adjusted based on the detected temperature.
The auxiliary fuel flow rate of the gasification furnace is detected, and the auxiliary air amount is adjusted based on the detected auxiliary fuel flow rate.
[0015]
By adopting such a configuration, it is possible to optimally control both the temperature of the gasification furnace and the temperature of the melting furnace simultaneously by supplying the auxiliary fuel and the auxiliary air to the gasifier in combination with the fluctuation of the waste quality. .
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
A fluidized bed gasification and melting furnace apparatus according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing an overall configuration of a fluidized bed gasification and melting furnace apparatus according to an embodiment of the present invention.
[0017]
Here, 1 is a refuse receiving device, 2 is a refuse receiving hopper, 3 is a refuse feeder, 4 is a rotary valve, 5 is a gasifier, 6 is a fluidized bed, 7 is a fluidized air diffuser, and 8 is a gasifier temperature. 9 is an auxiliary fuel supply nozzle, 10 is an auxiliary fuel flow control valve, 11 is an auxiliary air flow control damper, 12 is a pyrolysis gas flow, 13 is a swirling melting furnace, 14 is a melting furnace thermometer, 15 is a melting slag, Reference numeral 16 denotes a slag discharge port, 17 denotes a slag downflow, 18 denotes a combustion furnace outlet combustion gas, 19 denotes a secondary combustion furnace, and 20 denotes a waste heat recovery boiler.
[0018]
First, the basic configuration and function of the fluidized-bed gasification and melting furnace device will be described. In FIG. 1, waste to be incinerated is transferred from the waste receiving device 1 to the waste feeder 3 via the waste receiving hopper 2. It is sent to the gasification furnace 5 via the rotary valve 4. The supplied refuse generates a pyrolysis gas by a fluidized bed gasification reaction in a fluidized bed 6 at a lower portion of the gasification furnace 5. In the gasification, the air ratio of about 0.3 to 0.6 is supplied to the fluidized bed 6 from the fluidized air diffuser 7 as fluidized combustion air with respect to the supplied waste, and the fluidized bed temperature is maintained at 500 to 700 ° C. It is done by doing.
[0019]
The pyrolysis gas generated in the gasification furnace 5 is introduced into the swirling melting furnace 13 through a flue at the top of the gasification furnace. The pyrolysis gas performs swirling combustion in a melting furnace at an air ratio of about 1.0 and a high temperature equal to or higher than the melting point of ash. Due to the centrifugal force at the swirling part, the molten slag flows as a slag flow from the inclined lower wall of the swirling melting furnace 13 and flows downward by gravity from a slag discharge port 16 provided at the melting furnace outlet. The slag 17 that has flowed down is quenched into a granulated slag by being rapidly cooled in a granulation tank (not shown).
[0020]
After the combustion gas 18 separated from the slag in the swirling melting furnace 13 is completely burned in the secondary combustion furnace 19 and passes through the waste heat recovery boiler 20, the harmful gas component and the dust are passed through an exhaust gas treatment device not shown here. After removal, they are released to the atmosphere from the chimney.
[0021]
Here, the outline of the embodiment of the present invention will be described. In the fluidized bed waste gasification / melting furnace according to the present embodiment, fluidized bed gasification can be performed even with respect to fluctuations in waste quality and a wide variety of waste types. In order to stably generate the pyrolysis gas, it is necessary to always maintain the gasifier temperature within a certain range. Further, in order to melt and burn the pyrolysis gas generated in the gasification furnace in the swirling melting furnace, it is necessary to always maintain the combustion temperature of the swirling melting furnace within a certain range.
[0022]
In this embodiment, the auxiliary fuel is supplied to the gasifier at the same time as the auxiliary air is supplied to the gasifier based on the temperature of the melting furnace. The amount of generated fine particles is secured, and the melting furnace temperature in the swirling melting furnace on the downstream side can be maintained at a predetermined temperature. In this case, as shown in FIG. 1, the amount of auxiliary air can be controlled based on the measurement result of the gas thermometer 8.
[0023]
Therefore, the gasification furnace 5 according to the present embodiment is provided with a supply nozzle 9 for the auxiliary fuel. In FIG. 1, the auxiliary fuel supply nozzle 9 is provided at two places in the fluidized bed 6 and a space outside the fluidized bed 6, but either one may be used. In FIG. 1, the auxiliary air is connected to the auxiliary fuel supply nozzle 9 and the fluidized air diffuser 7 in the fluidized bed, but may be any one of them. It is also possible to supply the auxiliary air nozzle 9 'alone to the outside of the fluidized bed in the gasification furnace.
[0024]
As shown in the drawing, the opening of the auxiliary fuel flow control valve 10 is controlled by the output of the melting furnace thermometer 14, and the opening of the auxiliary air flow control damper 11 is controlled by the output of the gas furnace thermometer 8. I have. When the measured value of the thermometer 14 of the swirling melting furnace 13 which is the combustion part falls out of a certain range, the auxiliary fuel flow control valve 10 supplies the auxiliary fuel so as to recover the temperature, or opens the opening degree. Supply more. When the fluidized bed temperature 8 falls below a predetermined temperature range because the fluidized bed temperature 8 changes depending on the degree of auxiliary fuel addition (the temperature of the fluidized bed tends to decrease due to the consumption of sensible heat and vaporization heat when the supplementary fuel is supplied more). Is controlled to open the auxiliary air flow control damper 11 to increase the combustion exothermic reaction of the gasification furnace 5 to increase the temperature.
[0025]
To explain in greater detail, in the configuration of the present embodiment, as a means for simultaneously adjusting the temperatures of the gasification furnace and the melting furnace, the gasification furnace and the auxiliary air are supplied to the gasification furnace. For the two control objects of the melting furnace, two operating means of auxiliary fuel and auxiliary air can be controlled to appropriately control the temperature of each furnace. Specifically, the temperature of the melting furnace is detected by the melting furnace thermometer 14, the amount of the auxiliary fuel is adjusted based on the detected temperature, and the fluidized bed temperature changes with the supply of the auxiliary fuel. The amount of auxiliary air is detected by the gasification furnace thermometer 8, and the temperature of each of the gasification furnace and the melting furnace is individually adjusted by this series of control systems.
[0026]
Since the pyrolysis reaction of the gasifier usually has a low air ratio of 0.3 to 0.6, the exothermic reaction contributing to the rise in the temperature of the gasifier is controlled by the air-limited environment supplied to the gasifier. Was confirmed by experiments. Therefore, even if the auxiliary fuel is supplied at a constant air volume, the auxiliary fuel does not burn, and the gasification furnace temperature is sufficient to supplement the sensible heat of the auxiliary fuel and the heat of vaporization (when the fuel is liquid) with the heat input to the gasification furnace. Will decrease. In the state where the temperature of the gasification furnace is lowered, the combustible components necessary for combustion in the downstream melting furnace, that is, the amounts of pyrolysis gas and combustible fine particles are insufficient, the melting furnace temperature does not rise, and the slag conversion rate decreases. Issues arise.
[0027]
Therefore, it is effective to supply auxiliary gas with combustion air corresponding to the amount of combustion required for increasing the gasification furnace temperature as auxiliary air to the gasification furnace with respect to the gasification furnace temperature decrease due to the decrease in waste quality.
[0028]
On the other hand, the auxiliary fuel supplied to the gasification furnace is supplied to the melting furnace after leaving the gasification furnace as combustible gas, except for the amount of combustion consumed in the gasification furnace, so it is burned in the melting furnace. This will contribute to a rise in the temperature of the melting furnace.
[0029]
Thus, it becomes possible to distribute and adjust the heat input of the auxiliary fuel supplied to the gasification furnace to the gasification furnace and the melting furnace by the supply amount of the auxiliary air. Thereby, the temperature of the gasification furnace and the temperature of the melting furnace can be optimally adjusted with respect to the fluctuation of the waste quality.
[0030]
Next, a fluidized bed gasification and melting furnace apparatus and a control method thereof according to another embodiment of the present invention will be described below with reference to FIG. The components of the reference numerals shown in FIG. 2 are the same as those of FIG.
[0031]
In FIG. 2, if the supply amount of the auxiliary fuel to the gasifier 5 is known, the temperature decrease in the gasifier due to the auxiliary fuel supply can be predicted from the calculation and / or the test data. Therefore, the amount of air sufficient to compensate for the decrease in the gasifier temperature with respect to the supply of the auxiliary fuel can also be calculated in advance. Thus, by simultaneously adjusting the auxiliary air amount according to the increase and decrease of the supply amount of the auxiliary fuel, the auxiliary air amount can be controlled in advance by previously adjusting the auxiliary air amount according to the change in the gasification furnace temperature. .
[0032]
In FIG. 2, the opening of the auxiliary fuel flow control valve 10 is controlled by the output of the melting furnace thermometer 14 (control is performed so as to increase the auxiliary fuel when the temperature of the thermometer 14 is low), and the flow rate of the controlled auxiliary fuel is controlled. Is measured by the auxiliary fuel flow meter 8, and the opening of the auxiliary air flow rate adjusting damper 11 is controlled based on the measured value. That is, the opening degree of the auxiliary air flow adjustment damper 11 is set as a function of the measured value of the auxiliary fuel flow meter 8, and is supplied at a fixed ratio of the auxiliary fuel amount. In the second embodiment shown in FIG. 2, the same effect as in the embodiment shown in FIG. 1 can be obtained.
[0033]
【The invention's effect】
As described above, according to the present invention, the temperature of both the gasification furnace and the melting furnace is simultaneously optimally controlled by supplying the auxiliary fuel and the auxiliary air to the gasification furnace in combination with the fluctuation of the waste quality. it can.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a fluidized bed gasification / melting furnace apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing an overall configuration of a fluidized bed gasification and melting furnace apparatus according to another embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 refuse receiving device 2 refuse receiving hopper 3 refuse feeder 4 rotary valve 5 gasifier 6 fluidized bed 7 flowing air diffuser tube 8 gasifier thermometer 9, 9 'auxiliary fuel supply nozzle 10 auxiliary fuel flow control valve 11 auxiliary air Flow control damper 12 Pyrolysis gas flow 13 Rotating melting furnace 14 Melting furnace thermometer 15 Molten slag 16 Slag outlet 17 Slag downflow 18 Melting furnace outlet combustion gas 19 Secondary combustion furnace 20 Waste heat recovery boiler

Claims (6)

In a fluidized bed gasification and melting furnace apparatus comprising: a fluidized bed gasifier for pyrolyzing and gasifying refuse; and a melting furnace for burning flammable gas and combustible particles generated by pyrolysis of refuse at a high temperature. ,
A fluidized bed gasification / melting furnace apparatus, wherein auxiliary gas and auxiliary air are supplied to the gasification furnace. In claim 1,
A fluidized bed gasification / melting furnace apparatus, wherein an auxiliary fuel inlet and an auxiliary air port to be supplied to the gasification furnace are provided in a space above a fluidized bed. In claim 1,
A fluidized bed gasification / melting, wherein an auxiliary fuel inlet for supplying to the gasifier is provided in a fluidized bed, and the auxiliary air is added to fluidized air to a diffuser pipe and supplied into the fluidized bed. Furnace equipment. In claim 1,
A fluidized bed gasification / melting furnace apparatus in which an auxiliary fuel inlet for supplying to the gasification furnace is provided in a space above a fluidized bed, and the auxiliary air is added to fluidized air to a diffuser pipe and supplied to the fluidized bed. . In claim 1, 2, 3, or 4,
Detecting the temperature of the melting furnace, adjusting the auxiliary fuel flow rate based on the detected temperature,
A fluidized bed gasification and melting furnace apparatus, wherein a fluidized bed temperature of the gasification furnace is detected, and an auxiliary air amount is adjusted based on the detected fluidized bed temperature. In claim 1, 2, 3, or 4,
Detecting the temperature of the melting furnace, adjusting the auxiliary fuel flow rate based on the detected temperature,
A fluidized-bed gasification and melting furnace apparatus, wherein the auxiliary fuel flow rate of the gasification furnace is detected, and the auxiliary air amount is adjusted based on the detected auxiliary fuel flow rate.

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