JP2023074194A - Method for operating waste gasification facility and waste gasification facility - Google Patents

Abstract

To provide a method for operating a waste gasification facility, capable of starting regular operation promptly, and to provide the waste gasification facility.SOLUTION: A method for operating a waste gasification facility is provided, wherein: the waste gasification facility has a gasifier and a dust collector; in the gasifier, oxygen-containing gas and a combustible-containing waste are introduced, and thermal decomposition of a combustible is performed to generate a combustible gas-containing exhaust gas; the dust collector removes a soot from the exhaust gas; the waste gasification facility heats the gasifier and performs start-up operation to start up the gasifier. In the start-up operation, waste or another combustible material is used as a start-up fuel; the start-up fuel is burned in the gasifier to heat the gasifier; and the combusted exhaust gas of the start-up fuel is discharged from the gasifier as a start-up exhaust gas. In the start-up operation, the oxygen-containing start-up exhaust gas is discharged from the gasifier; and water is added to the start-up exhaust gas upstream of the dust collector.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method of operating a waste gasification facility and a waste gasification facility, and more particularly, to a waste gas provided with a gasification furnace that thermally decomposes waste and discharges exhaust gas containing combustible gas. The present invention relates to a method of operating a waste gasification facility and a waste gasification facility.

Conventionally, combustible gases such as hydrogen, carbon monoxide, and methane are generated by thermally decomposing waste containing combustibles in a gasification furnace. This combustible gas is used as a fuel or a raw material for producing fuel. Exhaust gas discharged from a gasification furnace in this type of facility contains gas, mist, soot, etc. other than combustible gas. In this type of facility, the exhaust gas emitted from the gasification furnace is effectively used as fuel after removing solid matter such as soot with a dust collector and removing mist and water-soluble gas with a gas scrubber.

Patent Literature 1 listed below discusses a method related to start-up operation from operating the above equipment to steady operation. In addition, Patent Document 2 below describes a start-up operation in a facility for gasifying coal, and is intended to prevent combustion of deposits in a porous filter that filters exhaust gas discharged from the gasification furnace. The use of an inert gas is disclosed to adjust the oxygen concentration of the exhaust gas.

JP 2010-25378 A JP 2014-152300 A

The internal temperature of the gasifier in the resting state is lower than that in steady operation, and in some cases, it has completely cooled down. Therefore, at the time of start-up operation of the waste gasification equipment, it is possible to shorten the time until transition to steady operation by introducing sufficient oxygen into the gasification furnace to increase the amount of heat generated inside. However, although this can shorten the time required for start-up, a large amount of oxygen may be contained in the exhaust gas at the time of start-up. If such exhaust gas is introduced into the dust collector at the time of start-up, there is a risk that soot and the like will burn inside the dust collector. Unlike coal gasifiers, waste gasifiers typically do not have ready access to inert gas. For this reason, waste gasification equipment and its operating method are desired to be started up in a favorable manner and quickly transitioned to steady operation, but such demands are not fully satisfied. Accordingly, an object of the present invention is to provide a method of operating a waste gasification facility and a waste gasification facility capable of promptly starting steady operation.

In order to solve the above problems, in the present invention,
A method of operating a waste gasification facility, comprising:
The waste gasification equipment comprises a gasification furnace and a dust collector,
In the gasification furnace, gas containing oxygen and waste containing combustible material are introduced, and the combustible material is thermally decomposed to generate exhaust gas containing combustible gas,
In the dust collector, soot contained in the exhaust gas discharged from the gasification furnace is removed,
In the waste gasification facility,
A start-up operation is performed to heat the gasification furnace and start the gasification furnace,
In the start-up operation,
Either the waste or a combustible material other than the waste is used as a startup fuel,
The start-up fuel is burned in the gasification furnace to heat the gasification furnace, and the combustion exhaust gas of the start-up fuel is discharged from the gasification furnace as start-up exhaust gas,
In the start-up operation, the start-up exhaust gas containing oxygen is discharged from the gasification furnace;
A method of operating a waste gasification facility is provided, wherein water is added to the exhaust gas at the time of startup on the upstream side of the dust collector.

In order to solve the above problems, in the present invention,
A waste gasification facility comprising a gasification furnace and a dust collector,
Having an exhaust gas route from the gasification furnace to the dust collector,
In the gasification furnace, gas containing oxygen and waste containing combustible material are introduced, and the combustible material is thermally decomposed to generate exhaust gas containing combustible gas,
In the dust collector, the exhaust gas generated in the gasification furnace flows through the exhaust gas passage, and soot contained in the exhaust gas is removed,
Provided is a waste gasification facility further comprising a water adding device capable of adding water upstream of the dust collector to the exhaust gas supplied to the dust collector through the exhaust gas route.

In the present invention, it is possible to reduce the oxygen concentration of the exhaust gas by adding water to the exhaust gas, which is a simple operation, but the added water becomes a large amount of water vapor, and the temperature of the exhaust gas can be lowered by the heat of vaporization. Therefore, in the present invention, it is possible to quickly reach a temperature suitable for steady operation of the gasification furnace while preventing the soot adhering to the dust collector from burning. That is, according to the present invention, it is possible to provide a waste gasification facility and a method of operating the waste gasification facility that can quickly start steady operation.

FIG. 1 is a schematic diagram showing the conditions of the equipment constituting the waste gasification facility and the process flow. FIG. 2 is a schematic diagram showing the initial state of start-up operation in the waste gasification facility. FIG. 3 is a schematic diagram showing the final stage of start-up operation in the waste gasification facility. FIG. 4 is a schematic diagram showing how the operation of the waste gasification equipment shifts from startup operation to normal operation.

An embodiment of the present invention will be described with reference to the drawings. First, the waste gasification equipment will be described with reference to the example of FIG. The waste gasification equipment of this embodiment is configured to thermally decompose waste containing combustibles during steady operation, generate combustible gas through the thermal decomposition, and effectively utilize the combustible gas. ing.

The waste gasification facility 1 shown in FIG. and a gasification furnace 20 for thermally decomposing the The gasification furnace 20 is configured to introduce a gas containing oxygen, burn the waste in a reducing atmosphere, and discharge an exhaust gas containing a combustible gas. The waste gasification facility 1 of this embodiment further includes a gas supply device 30 for supplying oxygen-containing gas to the gasification furnace 20 .

The specific form of the gasifier 20 is not particularly limited, but for example, it may be a fluidized bed gasifier having a fluidized bed. The waste gasification equipment 1 is provided with a gas supply path GS for supplying the gas from the gas supply device 30 to the gasification furnace 20 . The gas supply path GS is provided to supply the gas to the bottom of the gasification furnace 20 as a fluidizing gas for fluidizing the fluidized bed (not shown) of the gasification furnace 20. good too.

The waste gasification equipment 1 is provided with a first fuel supply path (hereinafter also referred to as "first fuel supply path PS1") for supplying the waste in the waste storage facility 10 to the gasification furnace 20 as fuel. ) is provided. The first fuel supply path PS1 may be provided to introduce the waste into the fluidized bed.

In the waste gasification equipment 1, the combustible gas contained in the exhaust gas discharged from the gasification furnace 20 is effectively used. The waste gasification equipment 1 is provided with an exhaust gas route G1 for conveying exhaust gas from the gasification furnace 20 to a place where combustible gas is used. The exhaust gas discharged from the gasification furnace 20 contains not only combustible gas but also solid matter such as soot. The waste gasification equipment 1 is provided with a dust collector 40 for removing at least part of solids such as soot from the exhaust gas.

The dust collector 40 is not particularly limited in its dust collection method, but examples thereof include a filtration type and an adsorption type. That is, the dust collector 40 may have a filter or a suction plate. The dust collector may be a wet dust collector, such as a scrubber or a wet electrostatic precipitator, in which water is used to collect dust, or a dry dust collector in which water is not used. The wet dust collector can also be used as a gas scrubber 70, which will be described later.

Solid matter such as soot removed from the exhaust gas by the dust collector 40 can be returned to the gasification furnace 20 again as fuel. The waste gasification equipment 1 has a solids return route (not shown) for returning solids containing soot removed from the exhaust gas by the dust collector 40 to the gasification furnace 20 as fuel for burning in the gasification furnace 20. may have. Since the interior of the wet dust collector is wet, unintentional ignition due to soot adhering to the inner wall surface or the like is less likely to occur than in the dry dust collector. On the other hand, a dry dust collector can collect solid matter such as soot in a dry state, so that the solid matter can be easily used as fuel.

In the case of using the dust collector 40 or a gas cleaning device 70 (to be described later), such as a wet type electrostatic precipitator, which utilizes the dust collecting action by the Coulomb force, an oxygen concentration meter is installed upstream in order to prevent combustible gas from burning due to discharge. It may be provided to monitor the oxygen concentration in the exhaust gas. A laser oximeter can be used for monitoring the oxygen concentration. A laser oximeter is preferable in that it has good responsiveness and can quickly detect a change in oxygen concentration.

The exhaust gas path G1 of the present embodiment is provided so as to extend from the gasification furnace 20 to the dust collector 40 and further downstream from the dust collector 40 . In the waste gasification equipment 1 of the present embodiment, high-temperature exhaust gas (hereinafter referred to as "high-temperature exhaust gas X0") discharged from the gasification furnace 20 in the exhaust gas route G1 between the gasification furnace 20 and the dust collector 40 A heat recovery device 50 is provided for recovering thermal energy by exchanging heat with a heat source. Further, the waste gasification equipment 1 of the present embodiment includes a water adding device 60 capable of adding water to the exhaust gas supplied to the dust collector 40 through the exhaust gas route G1 upstream of the dust collector 40. further provided.

The waste gasification facility 1 of this embodiment is equipped with one or more temperature measuring devices for measuring the temperature of the exhaust gas flowing through the exhaust gas route G1. The waste gasification facility 1 of this embodiment is equipped with a plurality of temperature measuring devices. A first temperature measuring device (hereinafter also referred to as “first temperature measuring device T1”) among the plurality of temperature measuring devices measures the temperature of the exhaust gas discharged from the gasification furnace 20 (hereinafter referred to as “gasification furnace outlet temperature t0”) is measured before the heat recovery device 50 (upstream side).

The heat recovery device 50 of this embodiment has a heat exchanger (not shown) through which a heat medium for heat recovery flows. The heat recovery device 50 may be able to arbitrarily adjust the flow rate of heat medium per unit time in a heat exchanger (not shown). That is, the heat recovery device 50 may have a heat medium amount adjuster (not shown) capable of adjusting the flow rate of the heat medium.

The hydrating device 60 includes a nozzle (not shown) for discharging water into the exhaust gas and a water supply device (not shown) such as a pump for supplying water to the nozzle. The hydrating device 60 may be capable of adjusting the amount of water added per unit time to the exhaust gas. That is, the water supply device (not shown) of the hydrating device 60 may be able to adjust the amount of water added per unit time to the exhaust gas.

A second temperature measuring device (hereinafter also referred to as “second temperature measuring device T2”) among the plurality of temperature measuring devices measures the temperature of the exhaust gas introduced into the dust collector 40 (hereinafter referred to as “dust collector inlet temperature t2”). (also referred to as ) can be measured. The second temperature measuring device T2 can measure the temperature of the exhaust gas downstream from the point where water is supplied by the water adding device 60 .

The hydrating device 60 of the present embodiment adds water to the exhaust gas heat-exchanged by the heat recovery device 50 (hereinafter also referred to as “primary cooling exhaust gas X1”) as necessary, and the latent heat of evaporation of the water is It is configured such that the primary cooling exhaust gas X1 can be changed into further cooled exhaust gas (hereinafter also referred to as "secondary cooling exhaust gas X2") by utilizing the primary cooling exhaust gas X1.

In order to prevent the exhaust gas from passing through the dust collector 40 as necessary, the waste gasification facility 1 of the present embodiment has a branch path G2 branched from the exhaust gas path G1 upstream of the dust collector 40. have. Further, the waste gasification facility 1 of the present embodiment is provided with a circulation path C1 so as to circulate and supply hot air to the dust collector 40 to heat the dust collector 40 . The circulation path C1 is equipped with a hot air circulation device B1.

The waste gasification facility 1 of the present embodiment has a first state in which exhaust gas is supplied downstream through the dust collector 40 and a second state in which exhaust gas is supplied downstream through the branch route G2 without passing through the dust collector 40. A switching valve V1 is provided for switching the path of the exhaust gas between the two states. Further, in this embodiment, the switching valve V1 is provided so as to form a circulating flow of warm air passing through the dust collector 40 through the circulation path C1 in a state where exhaust gas is not circulated through the dust collector 40.

The waste gasification equipment 1 of the present embodiment further has a gas scrubber 70 for washing the exhaust gas from which the soot has been removed by the dust collector 40 with water, and the exhaust gas (hereinafter referred to as , also referred to as “purified exhaust gas X3”) to a gas using device 80 that effectively utilizes combustible gas.

The gas scrubber 70 may be of a simple submerged weir structure. The gas scrubber 70 is, for example, a scrubber that has a filler layer in which a plurality of fillers are deposited with gaps therebetween, and sprays water on the filler layer while circulating the exhaust gas so as to pass through the filler layer. It may be provided.

The dust collector 40 and the gas scrubber 70 do not have to be provided separately in the waste gasification facility 1 and may be integrated. In this embodiment, the dust collector 40 and the gas scrubber 70 can also be used as a wet dust collector or the like. When the dust collector 40 and the gas scrubber 70 are integrated, the number of devices constituting the waste gasification facility 1 is reduced compared to when the dust collector 40 and the gas scrubber 70 are provided separately. space can be saved. On the other hand, when the dust collector 40 and the gas scrubber 70 are provided separately, the frequency of wastewater treatment by the gas scrubber 70 can be reduced.

The waste gasification equipment 1 of the present embodiment further includes a gas analyzer 90 capable of measuring the content (concentration) of combustible gas, oxygen, etc. contained in the purified exhaust gas X3 after being cleaned by the gas cleaning device 70. I have. The waste gasification equipment 1 of the present embodiment is provided with a bypass route G3 that branches off from the exhaust gas route G1 downstream of the gas scrubber 70 and is connected to the exhaust gas route G1 again downstream of the branch point. The purified exhaust gas X3 can also flow through the bypass route G3. In this embodiment, the gas analyzer 90 is arranged so that the purified exhaust gas X3 passing through the bypass route G3 can be analyzed.

The method of using the purified exhaust gas X3 in the gas using device 80 of the present embodiment is not particularly limited, but for example, the gas using device 80 may be a device for concentrating combustible gas. can. The gas using device 80 separates, for example, at least a portion of the non-combustible gas ( _N2, etc.) contained in the purified exhaust gas X3 so that the concentration of the combustible gas ( _H2 , CO, _CH4 , etc.) It may be a device capable of producing a high-concentration gas higher than that. The gas using device 80 includes a primary storage portion (not shown) that primarily stores the purified exhaust gas X3, and a gas separation portion (not shown) that separates nitrogen gas from the purified exhaust gas X3 stored in the primary storage portion. and a secondary storage section (not shown) for storing high-concentration gas from which at least part of the nitrogen gas has been removed in the gas separation section (not shown) to improve the concentration of combustible gas. may have. The gas separation section (not shown) may be configured by, for example, a pressure swing adsorption (PSA) device.

The waste gasification facility 1 of the present embodiment may be configured so that the purified exhaust gas X3 and the high-concentration gas can be used as fuel for the gasification furnace 20 . That is, the waste gasification equipment 1 has a gas return path (not shown) for returning at least one of the purified exhaust gas X3 and the high-concentration gas to the gasification furnace 20 as fuel for burning in the gasification furnace 20. may have

In the waste gasification equipment 1 of this embodiment, as a result of the gas analysis device 90, it is determined that the exhaust gas (purified exhaust gas X3) is not suitable for supplying to the gas using device 80, such as when the concentration of combustible gas is low. An incinerator 100 for incinerating the exhaust gas in such a case, and a gas treatment apparatus 110 for treating the incinerated gas discharged from the incinerator 100 so that it can be released outside the system such as the atmosphere. further provided.

The gas analyzer 90 can be equipped with a multi-component analyzer (CO/CO ₂ /CH ₄ .

The waste gasification facility 1 of the present embodiment is designed to convert combustibles other than waste, such as gaseous combustibles such as city gas and liquid combustibles such as petroleum (kerosene, light oil, heavy oil, etc.). A fuel supply device P1 is further provided so that the fuel in the gasification furnace 20 can be used. The fuel supply device P1 is provided to supply fossil fuel as described above to the gasifier 20 as required. For supplying fuel from the fuel supply device P1 to the gasification furnace 20, a second fuel supply path (hereinafter also referred to as "second fuel supply path PS2") different from the first fuel supply path PS1 is used. is used. In this embodiment, a third fuel supply path (hereinafter also referred to as "third fuel supply path PS3") is provided for supplying fuel from the fuel supply device P1 to the incinerator 100 as needed. there is

The waste gasification facility 1 of the present embodiment is provided with a blower B2 that serves as power for transporting the exhaust gas flowing through the exhaust gas route G1. The blower B2 is provided downstream of the gas scrubber 70. As shown in FIG. The blower B2 functions to suck the exhaust gas from the exhaust gas route G1 on the upstream side of the point where the blower B2 is arranged. It functions to force-feed the exhaust gas to the exhaust gas path G1 on the downstream side.

In the waste gasification equipment 1 of the present embodiment, the flow rate of the heat medium per unit time in the heat exchanger in the heat recovery device 50 is equal to that in the first temperature measurement device T1 or the second temperature measurement device T2. It may be changeable based on the measurement results. That is, the heat transfer medium amount controller of the heat recovery device 50 may be configured to be operated based on the measurement result of a temperature measuring device that measures the temperature of the exhaust gas. According to such an aspect, it becomes easy to adjust the amount of heat to be recovered and the temperature of the heat medium after heat exchange, and it becomes easy to adjust the temperature of the primary cooling exhaust gas X1.

In the waste gasification equipment 1 of the present embodiment, the amount of water added to the exhaust gas per unit time by the water addition device 60 is determined by the measurement results of the first temperature measurement device T1 and the second temperature measurement device T2. It may be changeable based on That is, the water supply machine may be configured to be operated based on the measurement result of a temperature measuring device that measures the temperature of the exhaust gas.

Regarding the waste gasification facility 1 of the present embodiment, conventionally known technical matters can be adopted for devices and their specific configurations that are not directly specified in the above examples.

A method of operating such a waste gasification facility 1 will be described below.
In the operation method of the waste gasification equipment 1, the start-up operation is performed in the transitional period from the start of the operation of the equipment in the resting state to the steady operation.

In the start-up operation, either the waste or a combustible material other than the waste is supplied as start-up fuel to the gasification furnace 20 whose temperature is lower than that during the steady operation, and the gasification is performed. A temperature rise of the furnace 20 is performed. Another combustible material may be city gas supplied from the fuel supply device P1. Also, the start-up fuel may be a combustible gas (purified exhaust gas X3, high-concentration gas, etc.) produced before the waste gasification facility 1 enters a resting state.

In the start-up operation, the start-up fuel is burned in the gasification furnace 20 to heat the gasification furnace 20, and the combustion exhaust gas of the start-up fuel is discharged from the gasification furnace as the start-up exhaust gas. In the start-up operation, the start-up exhaust gas containing oxygen is discharged from the gasification furnace, and water is added to the start-up exhaust gas by the water adding device 60 on the upstream side of the dust collector 40. adding is performed.

Before the start-up operation, that is, for a while after the operation of the gasification furnace 20 is started, it is preferable to mainly use the fossil fuel supplied from the fuel supply device P1 rather than the waste as the fuel. The ratio of waste (the ratio of the amount of oxygen required for complete combustion) to the fuel mainly composed of fossil fuel, which is preferably used in the preceding stage of the start-up operation, can be 25% or less. The proportion may be 10% or less, 5% or less, or substantially 0%.

At this time, the waste can be supplied to the gasification furnace 20 through the first fuel supply path PS1. Fossil fuel can be supplied to the gasification furnace 20 through the second fuel supply path PS2 with the fluidized bed as the main object to be heated.

In the latter stage of the start-up operation, that is, in the stage before steady operation, it is preferable to increase the amount of waste contained in the fuel compared to the previous stage. In the latter stage of the start-up operation, it is preferable to use fuel mainly composed of waste. The ratio of fossil fuel (the ratio in the amount of oxygen required for complete combustion) in the fuel mainly composed of waste, which is preferably used in the preceding stage of the start-up operation, can be 45% or less. The proportion may be 30% or less, 15% or less, or substantially 0%.

The timing of increasing the proportion of waste in the fuel supplied to the gasification furnace 20 can be implemented based on the heating conditions inside the gasification furnace 20 . In the present embodiment, a reference value (hereinafter also referred to as "furnace temperature reference value") is provided for the heating condition (for example, the temperature of the fluidized bed) inside the gasification furnace 20, and the fuel is heated according to the furnace temperature reference value. Switching should be performed.

The in-furnace temperature reference value set to determine the timing of increasing the proportion of waste in the fuel supplied to the gasification furnace 20 is, for example, 350° C. or higher and 750° C. or lower in the case of the temperature of the fluidized bed. It can be anything in the range.

Combustion of the start-up fuel in the gasification furnace 20 of the present embodiment is performed by supplying a gas containing oxygen at an air ratio exceeding 1 from the gas supply device 30 . Since the start-up fuel is completely burned in a state in which oxygen remains, the gasification furnace 20 can quickly reach a desired temperature in this embodiment. At this time, since water is added to the start-up exhaust gas by the hydrating device 60, the start-up exhaust gas flowing through the exhaust gas path G1 on the downstream side of the water adding device 60 contains a large amount of water vapor. That is, the oxygen concentration of the exhaust gas at startup is greatly reduced by the hydrating device 60 . Further, when the water added by the water addition device 60 turns into steam, the latent heat of vaporization lowers the temperature of the exhaust gas at startup. Therefore, the temperature of the exhaust gas is greatly lowered by the hydrating device 60 at the time of start-up.

When the exhaust gas path G1 is configured by a duct or the like, combustible solid matter such as soot may adhere to the inner wall surface or the like. In this embodiment, since the oxygen concentration in the exhaust gas is lowered and the temperature is lowered at the time of startup, it is possible to suppress the possibility that combustible substances such as soot will accidentally ignite. In order to more reliably exhibit such a function, the degree of water addition by the water addition device 60 may be carried out based on the measurement result of the second temperature measurement device T2 as described above. In the start-up operation of the present embodiment, the temperature of exhaust gas at start-up introduced into the dust collector 40 (the temperature measured by the second temperature measuring device T2) is set to a reference value (hereinafter also referred to as a “secondary cooling reference value”). may be provided, and the operation of the hydrating device 60 may be controlled based on the secondary cooling reference value.

In this embodiment, the temperature of the exhaust gas is measured at the dust collector 40 or on the upstream side of the dust collector 40 at the time of startup, and the amount of water added per unit time in the water adding device 60 is adjusted based on the measurement result. and may be implemented. The temperature measurement may be performed on the exhaust gas at startup on the downstream side of the water adding device 60 or on the exhaust gas at startup on the upstream side. The amount of water added by the water adding device 60 may be varied stepwise or continuously. The amount of water added by the water adding device 60 may be varied by PID control, for example.

The water addition device 60 in the start-up operation can be switched between a low water addition state in which the amount of water added per unit time is relatively small and a high water addition state in which the amount of water added per unit time is larger than that in the low water addition state. and, when the result of the temperature measurement is a higher temperature than the low water addition state, the operation may be performed in the high water addition state. When the temperature is measured downstream of the adding device 60, the high-addition state and the low-addition state may be switched so that the result of the temperature measurement becomes a value close to the reference temperature.

The hydration device 60 is configured so that the temperature of the exhaust gas at the time of startup introduced into the dust collector 40 is below the reference value and is not much lower than the reference value (for example, (reference value - x ° C.) or higher than the reference value It is preferable that the amount of water added can be adjusted so as to satisfy the following range (where x>0). The temperature (x°C) below the reference value can be, for example, within 50°C. The temperature (x°C) below the reference value may be within 30°C, for example. The temperature (x° C.) below the reference value can be, for example, 5° C. or higher, and may be 10° C. or higher.

The temperature of the secondary cooling reference value can be, for example, 350° C. or lower. The secondary cooling reference value may be any temperature of 300° C. or less, or any temperature of 250° C. or less. The temperature of the secondary cooling reference value can be, for example, 100° C. or higher. The secondary cooling reference value may be any temperature of 120° C. or higher, or any temperature of 150° C. or higher.

In the start-up operation, as the temperature of the gasification furnace 20 rises, the air ratio in internal combustion may be made lower than that at the start. As a result, the inside of the furnace may be made into a reducing atmosphere, and the content of combustible gas in the exhaust gas may be increased at the time of start-up. Switching of the air ratio is performed by either one or both of the measurement result (gasification furnace outlet temperature t0) of the first temperature measurement device T1 and the measurement result (dust collector inlet temperature t2) of the second temperature measurement device T2. may be implemented based on Switching of the air ratio is preferably performed based on both the measurement result of the first temperature measurement device T1 and the measurement result of the second temperature measurement device T2.

In the present embodiment, a reference value (hereinafter also referred to as "outlet temperature reference value") may be set for the gasification furnace outlet temperature t0 for the reasons described above. The outlet temperature reference value for determining the switching timing of the air ratio can be, for example, 800° C. or higher. The outlet temperature reference value may be, for example, 850° C. or higher, 900° C. or higher, or 950° C. or higher. The outlet temperature reference value can be, for example, 1200° C. or lower. The outlet temperature reference value may be, for example, 1150° C. or lower, or 1100° C. or lower. The gasification furnace outlet temperature t0 is considered to have reached a stable state when the state is equal to or higher than the outlet temperature reference value and the temperature fluctuation range is within 50°C for a certain period of time or longer (for example, 1 minute or longer). be able to. In addition, the dust collector inlet temperature t2 also reached a stable state when the state was equal to or higher than the secondary cooling reference value and the temperature fluctuation range was within 50 ° C for a certain period of time or longer (for example, 1 minute or longer). can be regarded as The switching of the air ratio is preferably performed when it is confirmed that both have entered a stable state.

At the time of starting the operation of the gasification furnace 20 in the resting state, it is possible to sufficiently secure the amount of heat generated by fuel combustion if sufficient oxygen is supplied. However, if the air ratio is excessively high, the amount of heat taken out as exhaust gas during start-up also increases, making it difficult for the fuel to be efficiently used to heat the gasification furnace 20 .

The air ratio at the time of starting the operation of the gasifier 20 in the resting state (hereinafter also referred to as the “initial start-up air ratio”) is, for example, in any range of more than 1.0 to 1.5 or less. can be a value. The startup initial air ratio may be 1.1 or more. The startup initial air ratio may be 1.4 or less.

The air ratio in the present embodiment is represented by "air ratio = air volume introduced into the gasification furnace/required theoretical air volume", and the "required theoretical air volume" refers to the waste and the waste. It is calculated as the amount of air theoretically required from the combustible composition of the fuel.

In the later stages of start-up operation, gasification of the fuel may be performed at the same air ratio as in steady-state operation. In the start-up operation, such switching of the air ratio may be performed multiple times. The switching may be performed such that the air ratio after switching is lower than that before switching.

The air ratio immediately before the steady operation (hereinafter also referred to as the "later startup air ratio") can be, for example, 0.9 or less. The post-startup air ratio may be 0.7 or less, or may be 0.5 or less. The post-startup air ratio is usually set to 0.2 or more. The post-startup air ratio may be 0.3 or more.

While the gasification furnace 20 is being heated by fuel mainly composed of fossil fuel, it is difficult to generate soot and the like. . Therefore, for a while after the operation of the gasification furnace 20 is started, for example, the switching valve V1 is operated, and the start-up exhaust gas is caused to flow downstream of the dust collector 40 through the branch path G2 as shown in FIG. You may do so. That is, for a while after the operation of the gasification furnace 20 is started, the dust collector 40 may not be supplied with exhaust gas at startup. In that case, it is preferable to heat the dust collector 40 separately, and the dust collector 40 may be heated by forming a circulation flow of hot air passing through the dust collector 40 through the circulation path C1.

While the start-up exhaust gas is not passed through the dust collector 40 and flows downstream, the start-up exhaust gas may be supplied to the incinerator 100 and incinerated. At that time, the fuel may be supplied from the fuel supply device P1 to the incinerator 100 through the third fuel supply path PS3 as required. The start-up exhaust gas may be supplied to the incinerator 100 without passing through not only the dust collector 40 but also the gas scrubber 70 , or may be supplied to the incinerator 100 through the gas scrubber 70 .

As described above, in this embodiment, the blower B2 is provided on the downstream side of the gas scrubber 70, and the start-up exhaust gas that has passed through the gas scrubber 70 is sucked by the blower B2. Therefore, in the start-up operation of the present embodiment, the gas cleaning device 70 cleans the start-up exhaust gas with water, and the gas cleaning device 70 puts the start-up exhaust gas into a negative pressure state. are easily compatible. It is possible to prevent the exhaust gas from leaking outside from the gas scrubber 70 during startup by cleaning the exhaust gas with water while keeping the exhaust gas in a negative pressure state at the gas scrubber 70 during startup.

When the startup exhaust gas (high-temperature exhaust gas X0) immediately after being discharged from the gasification furnace 20 reaches a predetermined temperature or higher, the ratio of waste in the fuel increases. Exhaust gas may be passed through the dust collector 40 . Also at this time, as shown in FIG. 3, the start-up exhaust gas may be supplied to the incinerator 100 and incinerated.

Switching from a state in which the waste gas is not passed through the dust collector 40 at startup to a state in which the waste gas is passed through the dust collector 40 can be timed to increase the amount of waste supplied to the gasification furnace 20 . Therefore, the switching may be performed based on the in-furnace temperature reference value. The in-furnace temperature reference value set to determine the timing of supplying exhaust gas to the dust collector 40 at startup is the same as the in-furnace temperature reference value set to determine the timing of increasing the proportion of waste in the fuel. They may be exactly the same temperature or different temperatures. The furnace temperature reference value, which is set to determine the timing of supplying the exhaust gas to the dust collector 40 at startup, determines the timing of increasing the proportion of waste in the fuel in terms of suppressing complication of control. It is preferably selected from the range of 450° C. or higher and 750° C. or lower, similarly to the furnace temperature reference value set in (1), and both are preferably the same temperature.

In the start-up operation, the oxygen content of the exhaust gas at the time of start-up is further determined by the above-mentioned oxygen concentration meter or the like, and when the oxygen content becomes less than a preset reference value, at the time of start-up You may make it stop adding the said water with respect to waste gas. The reference value for the oxygen content (hereinafter also referred to as “oxygen reference value”) can be a value selected from the range of 0% by volume or more and 2% by volume or less, for example. The oxygen reference value may be a value selected from the range of 0% by volume or more and 1% by volume or less. The oxygen reference value may be a value selected from 0% by volume or more and 0.5% by volume or less. The oxygen reference value may be 0% by volume.

In the startup operation, the combustible gas content of the exhaust gas at startup is further determined, and when the combustible gas content exceeds a preset reference value, the exhaust gas at startup is You may make it stop adding the said water. Among combustible gases, the reference value for hydrogen gas (hereinafter also referred to as “hydrogen reference value”) can be a value selected from the range of 15% by volume or more and 35% by volume or less. The hydrogen reference value may be a value selected from the range of 20% by volume or more and 30% by volume or less. Among combustible gases, the reference value for carbon monoxide gas (hereinafter also referred to as “carbon monoxide reference value”) can be a value selected from the range of 15% by volume or more and 35% by volume or less. The carbon monoxide reference value may be a value selected from the range of 20% by volume or more and 30% by volume or less. Among combustible gases, the standard value for methane gas (hereinafter also referred to as “methane standard value”) can be a value selected from the range of 3% by volume or more and 20% by volume or less. The methane reference value may be a value selected from the range of 5% by volume or more and 15% by volume or less.

When the combustible gas is generated as described above, the purified exhaust gas X3 is supplied to the gas using device 80 as shown in FIG. . Thus, in this embodiment, it is possible to quickly start steady operation. It should be noted that the operation method of the waste gasification facility of the present embodiment is not limited to the above example, and various modifications can be made as long as the effects of the present invention are not significantly impaired.

1: Waste gasification facility, 10: Waste storage facility, 20: Gasification furnace, 30: Gas supply device, 40: Dust collector, 50: Heat recovery device, 60: Hydration device, 70: Gas cleaning device, 80: Gas use device, 90: gas analyzer, 100: incinerator, 110: gas treatment device, B1: warm air circulation device, B2: air blower, C1: circulation route, G1: exhaust gas route, G2: branch route, G3: Bypass route, GS: gas supply route, P1: fuel supply device, T1: first temperature measuring device, T2: second temperature measuring device, V1: switching valve, X0: high temperature exhaust gas, X1: primary cooling exhaust gas, X2: Secondary cooling exhaust gas, X3: purified exhaust gas

Claims (6)

A method of operating a waste gasification facility, comprising:
The waste gasification equipment comprises a gasification furnace and a dust collector,
In the gasification furnace, gas containing oxygen and waste containing combustible material are introduced, and the combustible material is thermally decomposed to generate exhaust gas containing combustible gas,
In the dust collector, soot contained in the exhaust gas discharged from the gasification furnace is removed,
In the waste gasification facility,
A start-up operation is performed to heat the gasification furnace and start the gasification furnace,
In the start-up operation,
Either the waste or a combustible material other than the waste is used as a startup fuel,
The start-up fuel is burned in the gasification furnace to heat the gasification furnace, and the combustion exhaust gas of the start-up fuel is discharged from the gasification furnace as start-up exhaust gas,
In the start-up operation, the start-up exhaust gas containing oxygen is discharged from the gasification furnace;
A method of operating a waste gasification facility, wherein water is added to the exhaust gas at the time of startup on the upstream side of the dust collector. In the start-up operation,
Measuring the temperature of the exhaust gas at the time of startup on the upstream side of the dust collector;
2. The method of operating a waste gasification facility according to claim 1, wherein the amount of said water added upstream of said dust collector is adjusted according to said temperature. The waste gasification equipment further has a gas cleaning device for cleaning the exhaust gas from which the soot has been removed by the dust collector with water,
In the start-up operation,
3. The method of operating a waste gasification facility according to claim 1 or 2, wherein said gas scrubber further cleans the waste gas with water while keeping the exhaust gas in a negative pressure state at the time of start-up. In the startup operation, the oxygen content of the exhaust gas during startup is further determined, and when the oxygen content becomes less than a preset reference value, the water is added to the exhaust gas during startup. 4. The method of operating a waste gasification facility according to any one of claims 1 to 3, wherein the addition is stopped. In the startup operation, the combustible gas content of the exhaust gas at startup is further determined, and when the combustible gas content exceeds a preset reference value, the exhaust gas at startup is 4. The method of operating a waste gasification facility according to any one of claims 1 to 3, wherein adding the water is stopped. A waste gasification facility comprising a gasification furnace and a dust collector,
Having an exhaust gas route from the gasification furnace to the dust collector,
In the gasification furnace, gas containing oxygen and waste containing combustible material are introduced, and the combustible material is thermally decomposed to generate exhaust gas containing combustible gas,
In the dust collector, the exhaust gas generated in the gasification furnace flows through the exhaust gas passage, and soot contained in the exhaust gas is removed,
A waste gasification facility further comprising a water adding device capable of adding water upstream of the dust collector to the exhaust gas supplied to the dust collector through the exhaust gas route.

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