JP2002349820A - Waste incinerator discharging no dioxins and the like at starting and stopping time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste incinerator discharging no dioxins and the like even at starting and stopping time, although starting and stopping the incinerator always cause the performance of low-temperature combustion to produce a large amount of dioxins and the like due to the fact that the waste incinerator produces a large amount of dioxins and the like at a low temperature. SOLUTION: When a waste incinerator is at a low temperature, the gas containing dioxins and the like is circulated and heated at a high temperature. Thereby, the dioxins and the like are decomposed, and the discharge of the dioxins and the like is prevented even at starting and stopping time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incinerator which does not emit dioxins even when it is started or stopped.

[0002]

2. Description of the Related Art Waste incinerators generate a large amount of dioxins at low temperatures. Starting and stopping the incinerator always causes low-temperature combustion, so the incinerator generates a large amount of dioxins. Therefore, incinerators that start and stop are avoided, and continuous furnaces that can be operated continuously are awarded. But,
The incinerator is not always operated with the amount of waste that can be operated continuously. If the amount of collected waste is small, it is necessary to start and stop the incinerator. With the current technology, incinerators that start and stop cannot be built to prevent the generation of dioxins.

[0003]

SUMMARY OF THE INVENTION The present invention provides a waste incinerator which can be started and stopped because no dioxins are generated at the time of starting and stopping.

[0004]

If the dioxins generated at the time of starting and stopping can be decomposed, a waste incinerator that can be started and stopped can be manufactured.

[0005] This is made possible by circulating a gas containing dioxins generated at the time of starting and stopping and heating the gas to a high temperature.

[0006]

FIG. 1 shows an embodiment of the present invention. 1 is a fluidized bed gasification furnace, 2 is a combustion melting furnace, 3 is a heating burner, 4 is a regenerator, 5 is a recirculation ejector, 6 is a recirculation blower, and 7 is a push-in blower. In the fluidized bed gasifier 1, waste is gasified by partial combustion in which a part of the waste is burned, and preheated air generated by the regenerator 4 is used as combustion air. Preheated air is also supplied to the combustion melting furnace 2 to burn the generated gas. The combustion gas exiting the combustion melting furnace 2 exchanges heat with combustion air in a regenerator 4. The combustion melting furnace 2 is provided with a burner 3 used for starting and stopping. The combustion air is supplied to the regenerator 4 by the forced air blower 7, preheated to a high temperature, and then supplied to the fluidized bed gasification furnace 1 and the combustion melting furnace 2.

At the time of start-up, auxiliary fuel is supplied to the burner 3 and burned, and the combustion gas is heat-exchanged with air by the regenerator 4 in a regenerative manner to produce preheated air, which is supplied to the fluidized bed gasifier 1. To a high temperature. When the temperature becomes sufficiently high, waste is supplied, but at this time, dioxins are generated because the temperature of the fluidized-bed gasification furnace 1 decreases. Therefore, the generated gas is pressurized by the recirculating blower 6 or the ejector 5 and circulated through the fluidized-bed gasification furnace 1. Since the generated gas contains dust and corrosive components, when the gas is heated to a high temperature, it passes through a recirculation blower having many movable parts and becomes dirty or corroded. Moreover, heat resistance is required and it becomes expensive. If an ejector using combustion air as a driving medium is used when the generated gas is at a high temperature, there is no movable part, so that it can be made robust and inexpensive. However, when the combustion air is not completely consumed at the time of startup, and air remains in the generated gas, if an ejector is used to recirculate the fluidized bed, new air is supplied as a driving medium, A large amount of fuel is required for the decomposition of dioxins. Therefore, when low-temperature combustion occurs at startup, a recirculation blower is used, and when the circulating gas becomes high in temperature, switching to an ejector is performed. This prevents extra air from being introduced during low-temperature combustion and protects the recirculation blower using an ejector when high-temperature combustion occurs. Since the volume of the generated gas is larger than the circulation space, it cannot be prevented from being completely exhausted to the outside. Therefore, the surplus generated gas is burned by supplying auxiliary fuel to the burner 3 in the combustion melting furnace 2 and heated to a high temperature. Decomposes dioxin. When the temperature of the fluidized bed gasifier 1 becomes high, the circulation of the generated gas is stopped.

At the time of stoppage, the supply of the waste is stopped while each part is kept at a high temperature. Then, since the amount of generated gas and the calorific value decrease, the temperature of each part decreases, and dioxins are generated in the generated gas. Then, the generated gas is heated by the burner 3 to decompose dioxins. When no generated gas is generated, the combustion of the burner 3 is stopped.

The combustion gas discharged from the combustion melting furnace 2 is
The dioxins are not decomposed and discharged to the outside because they are kept at a high temperature by the burner 3 even when starting and stopping.
Since the amount of heat of the high-temperature combustion gas is recovered by the regenerator 4, the amount of auxiliary fuel used can be minimized.

[0010]

According to the present invention, starting up in a waste incinerator
Dioxins generated due to low temperature during shutdown are decomposed by circulating and heating the generated gas, and the auxiliary fuel required for it is minimized.

[Brief description of the drawings]

FIG. 1 is an embodiment of the present invention.

[Explanation of symbols]

1: fluidized bed gasification furnace, 2: combustion melting furnace, 3: heating burner, 4: regenerator (air preheater), 5: recirculation ejector, 6: recirculation blower, 7: push-in blower

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F23G 5/14 F23C 11/02 301

Claims (1)

[Claims] 1. A waste incinerator characterized in that dioxins are not produced by circulating and heating generated gas at the time of starting and stopping.