JPH0526420A - Dust combustion method in dust incinerator - Google Patents

Abstract

PURPOSE:To reduce a rate of remaining of unburned gas and to perform a complete combustion of dust by a method wherein an amount of secondary air corresponding to that of primary air is supplied into a furnace body in such a way as a mixing with the remained unburned gas in discharged gas is promoted. CONSTITUTION:Hot primary air is blown from a lower part of each of a drying stoker 5, a combustion stoker 6 and a post-combustion stoker 7 to perform a stable combustion of dusts on each of the stokers. General discharging gas ascends in a furnace body 8 and reaches into a secondary combustion chamber 14. In turn, secondary air of an amount corresponding to the primary air is blown from a secondary air blower 11 into the secondary combustion chamber 14 so as to promote mixing with the remained unburned gas in the discharging gas. An amount of secondary air is about l/ 1.5 of the amount of primary air. Since the secondary air is blown in order to perform the secondary combustion, the secondary air is also set to a high temperature and the secondary combustion is made more effective.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of burning waste in an incinerator for reburning residual unburned gas in exhaust gas from the incinerator.

[0002]

2. Description of the Related Art Generally, combustible waste discharged from homes is collected and incinerated in a refuse incinerator as disclosed in, for example, JP-A-3-28617. Generally, such an incinerator has a hopper to which waste is supplied by a waste crane (not shown), a hopper chute that guides the waste from the hopper, and a waste extruder that transfers the waste of the hopper chute. It is provided with a dust device, a drying stoker that dries the dust supplied by the dust feeding device, a combustion stoker that burns the dust from the drying stoker, and a post-combustion stoker that burns the dust from the burning stoker and burns it. The dry stoker, the combustion stoker, and the post-combustion stoker are provided in the lower part of the furnace body, an exhaust gas cooling chamber is formed in the upper part of the furnace body, and an exhaust port for discharging exhaust gas is formed in the upper end of the furnace body.

High-temperature primary air is blown into the dry stoker, the combustion stoker, and the post-combustion stoker of the furnace body from their respective lower air blowing ports. In the dry stoker, the waste is transferred to the front while being stirred and unraveled, transported from the dry stoker to the combustion stoker, and is further burned by the combustion stoker while being stirred and unraveled, and is transferred to the front and post-burned. Carried to the stalker.

A blower, called a furnace cooling fan, provided near the exit of the furnace is operated to blow air at room temperature when the combustion temperature rises, and is introduced into the exhaust gas cooling chamber above the furnace body. The exhaust gas was being cooled.

That is, only when the combustion temperature due to the primary combustion rises, combustion was controlled by blowing cooling air as the exhaust gas temperature control at the furnace outlet of the refuse incinerator.

[0006]

As described above, the blower provided in the vicinity of the furnace outlet is called a furnace cooling fan, and is operated so as to blow when the furnace temperature becomes high, and the furnace temperature is controlled. However, it was not combustion control. In the secondary combustion of the conventional refuse incinerator, it is better to make the residence time longer by bringing the high temperature exhaust gas and unburned gas into contact with each other by devising the shape of the furnace body. The re-combustion air was not actively blown in for the secondary combustion of.

Under these circumstances, in recent years, due to problems such as dioxins, it has been required to achieve complete combustion of refuse. A higher level of complete combustion control has been demanded from the conventional furnace temperature control, which only requires the furnace temperature to be within a certain range. Achieving complete combustion requires C in the exhaust gas
It is evaluated by the O concentration, the amount of carbon remaining in the exhaust gas, and the like.

While the purification of the exhaust gas is demanded in this way, the dust in the combustor on the combustion stoker of the furnace body is completely burned or burned in a state close to that, and exhaust gas of complete combustion is generated, but it is dried. Since the garbage that has not dried sufficiently is burned in the dry pile on the stoker, exhaust gas of incomplete combustion is likely to be generated.

Therefore, in order to achieve complete combustion of dust, more stable combustion on the primary combustion side (waste supply amount, primary air amount control) and unburned gas in the high-temperature exhaust gas left behind in the primary combustion, In the secondary combustion section, it is required to mix with secondary air to promote secondary combustion.

However, even if an attempt is made to promote the secondary combustion, in the control for sending the secondary air to the secondary combustion section for cooling the furnace, the secondary air is not blown in particularly when the temperature of the furnace is lowered, so that the secondary air is not blown. The supply amount of air is insufficient with respect to the primary air amount, or the wind speed for mixing cannot be obtained, and it is far from achieving complete combustion. For example, the CO concentration is 10 to 100 times that of the normal furnace temperature. It may be a peak value.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to reburn unburned gas in exhaust gas generated in primary combustion to reduce the residual rate of unburned gas. It is an object of the present invention to provide a combustion control method in a refuse incinerator that can burn the refuse more completely.

[0012]

SUMMARY OF THE INVENTION The present invention is a waste incineration furnace waste combustion method that supplies primary air to a stoker of a waste incinerator to burn the waste and guides the exhaust gas to a furnace body. It is characterized in that the furnace body is supplied with secondary air in an amount corresponding to the primary air so as to promote mixing with unburned gas.

The amount of secondary air is preferably about 1 / 1.5 of the amount of primary air.

[0014]

In the present invention, the secondary air is supplied into the furnace body in an amount corresponding to the primary air so as to promote the mixing with the residual unburned gas in the exhaust gas.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a refuse incinerator according to an embodiment of the present invention. In FIG. 1, reference numeral 1 indicates a refuse incinerator. This waste incinerator 1 includes a hopper 2 to which waste is supplied by a waste crane (not shown), and this hopper 2.
From a hopper chute 3 that guides trash, a dust extruder having a trash chute 3 that transfers trash from the hopper chute 3, a drying stoker 5 that dries the dust supplied by the dust hopper, and a drying stoker 5 It is provided with a combustion stoker 6 that burns the waste and a post-combustion stoker 7 that burns the waste from the combustion stoker 6 and burns it. The waste extruder 4 is provided below the hopper chute 3.
Dry stoker 5, Burning stoker 6, Post-burning stoker 7
Is housed in a furnace body 8, and an exhaust port 9 for discharging combustion gas is formed at an upper end of the furnace body 8. A side wall surface of the furnace body 8 is provided with a cooling water supply port 10 and secondary air. A blower 11 is provided, and an auxiliary combustion burner 12 is provided at the lower end of the furnace body 8. Inside the furnace body 8, a primary combustion chamber 13 above the dry stoker 5, the combustion stoker 6, and the post-combustion stoker 7,
It is composed of a secondary combustion chamber 14 near the blower 11 for the secondary air and a gas cooling chamber 15 above the secondary combustion chamber 14.
The blower 11 for secondary air is provided directly above the primary combustion chamber 13 of the furnace body 8.

Then, one end of the air supply pipe 16 is connected to the dust pit 17, and the other end side is branched midway to connect to the lower part 8A of the drying stoker 5 of the furnace body 8 and a first branch pipe 16A, The second branch pipe 16B connected to the lower portion 8B of the combustion stoker 6 and the third branch pipe 16B connected to the lower portion 8C of the post combustion stoker 7.
It constitutes a branch pipe 16C. An air volume adjustment damper 16D, a primary air blower 18, and a primary air temperature adjustment damper 18A are provided in the middle of the air supply pipe 16. In the middle of the first branch pipe 16A, the primary air distribution first
The damper 19A, the primary air distribution second damper 19B is provided in the middle of the second branch pipe 16B, and the primary air distribution third damper 19C is provided in the middle of the third branch pipe 16C.

Further, a discharge pipe 20 is connected to the discharge port 9 of the furnace body 8, and an air preheater 21 and an electric dust collector 22 are provided in this order in the middle thereof. 1 of the air supply pipe 16
Heat exchange air pipes 23, 23 passing through the air preheater 21 are connected to both side portions of the next air temperature adjusting damper 18A. Exhaust gas in the exhaust pipe 20 and the primary air in the heat exchange air pipes 23, 23 are heat-exchanged with each other via the air preheater 21, so that the primary air in the air supply pipe 16 becomes hot and the exhaust pipe 20 The exhaust gas inside is cooled.

In the present embodiment, however, high temperature primary air is blown into the lower portion 8A of the dry stoker 5, the lower portion 8B of the combustion stoker 6, and the lower portion 8C of the post-combustion stoker 7, respectively, and the amount of dust supplied, By controlling the air amount and the like, the dust on the dry stoker 5, the combustion stoker 6, and the post-combustion stoker 7 is stably burned to generate exhaust gas, which rises in the furnace body 8 and reaches the secondary combustion chamber 14. .

On the other hand, an amount of secondary air corresponding to the primary air is blown into the secondary combustion chamber 14 from the secondary air blower 11 at an appropriate blowing speed, and the secondary combustion chamber 14 is blown.
Inside, mixing with residual unburned gas in the exhaust gas is promoted.
Here, the amount of secondary air is about 1 of the amount of primary air.
/1.5. Further, as for the secondary air, air at room temperature was used for the purpose of conventionally used for cooling the furnace, whereas in the present embodiment, the secondary air is blown mainly for the purpose of secondary combustion. The secondary air is also set to a high temperature, making secondary combustion more effective.

The exhaust gas produced by the secondary combustion rises together with the exhaust gas produced by the primary combustion, is guided to the gas cooling chamber 15, is cooled by the cooling water sprayed from the cooling water supply port 10, and is discharged from the discharge port 9. And is further cooled from the discharge pipe 20 through the air preheater 21.
Up to 2. In addition, the cooling operation of the furnace temperature when the furnace temperature rises is appropriately controlled by the operation of the amount of refuse feed.

According to the above-described structure, the secondary air is supplied into the furnace body 8 in an amount corresponding to the primary air so as to promote the mixing with the residual unburned gas in the exhaust gas. It is possible to promote the secondary combustion of the residual unburned gas in the generated exhaust gas, and thus reduce the residual rate of the unburned gas in the exhaust gas to burn the dust more completely.

Particularly, even when the furnace temperature is lowered, the secondary air is blown in, and the supply amount of the secondary air corresponds to the primary air amount, so that the secondary air amount does not become insufficient, or , Can obtain the wind speed of the secondary air for mixing,
Achieving near complete combustion, for example, CO concentration can be reduced.

In this embodiment, the amount of secondary air should be the amount corresponding to the primary air, and the amount of secondary air is about 1 / 1.5 of the amount of primary air. However, it is not limited to this value, and the air amount of the secondary air can be proportional to the air amount of the primary air by another appropriate ratio, and the air amount of the secondary air , It is also possible to have an appropriate functional relationship with the air amount of the primary air.

[0024]

As described above, according to the present invention,
Secondary air is supplied to the furnace body in an amount corresponding to the primary air so as to promote mixing with the residual unburned gas in the exhaust gas. This has the effect of promoting combustion, thus reducing the residual rate of unburned gas in the exhaust gas and allowing more complete combustion of dust.

Particularly, even when the furnace temperature is lowered, the secondary air is blown in, and the supply amount of the secondary air corresponds to the primary air amount, so that the amount of the secondary air does not become insufficient, or , Can obtain the wind speed of the secondary air for mixing,
This is close to achieving complete combustion, and has an effect of reducing CO concentration, for example.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refuse incinerator according to an embodiment of the present invention.

[Explanation of symbols] 1 garbage incinerator 5 dry stoker 6 burning stoker 7 After-burning stoker 8 furnace body

Claims (2)

[Claims] 1. A method for incinerating refuse in an incinerator, in which primary air is supplied to a stoker in an incinerator to burn the refuse and guide the exhaust gas to a furnace body, thereby promoting mixing with residual unburned gas in the exhaust gas. As described above, a method for burning waste in a refuse incinerator, which comprises supplying secondary air in an amount corresponding to the primary air into the furnace body. 2. The method of burning waste in a refuse incinerator according to claim 1, wherein the amount of secondary air is about 1 / 1.5 of the amount of primary air.