JPH0432289B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an incineration method in a circular stirring incinerator equipped with a large number of nozzle holes at the bottom of the furnace. This method is characterized by controlling the incineration conditions inside the furnace by blowing out low oxygen concentration exhaust gas or gas mixed with fresh air from the holes.

When incinerating materials to be incinerated, it is necessary to burn the entire material evenly in order to increase the incineration efficiency. For this purpose, it is important to uniformly apply air to the material to be incinerated. Regarding this point, in conventional circular stirring incinerators, a stirring blade is installed slightly above the hearth surface, and a large number of stirring hands hangs down from this stirring blade. It was blowing out air and stirring the material to be incinerated.

As mentioned above, the air supply for conventional circular stirring incinerators is by blowing air out from the stirring hand, and this method blows air uniformly onto the material to be incinerated, resulting in almost uniform combustion of the entire material. This is effective, and by opening the nozzle tangentially to the center of the furnace, it creates a swirling flow inside the furnace and has the effect of further promoting uniform combustion, but on the other hand, all of the air supplied to the furnace Since it is ejected from the fumarole, there are the following problems.

That is, the required amount of air naturally changes in response to changes in the amount of incineration, calorific value, moisture content, etc. of the material to be incinerated. Therefore, if you try to increase the amount of incineration or calorific value compared to steady operation, the amount of air supplied will increase accordingly, which will increase the air blowing speed and increase the pressure loss, resulting in an increase in the power of the blower. That's true. Furthermore, since the speed of air jetting out from the nozzle is high, the air is blown strongly onto the combustion surface of the incinerated material, causing the combustion surface to become extremely hot and causing the risk of clinker formation. . In addition, in combustion that reduces the amount of incineration and calorific value, the amount of air ejected is reduced, so the rectification effect is weakened, making it impossible to supply an average amount of air, and the cooling effect of air on the stirring blades and stirring hands is weakened. There was also a risk that these would be damaged due to overheating.

The present invention solves the above-mentioned drawbacks of the conventional incinerator, and the amount of air spewed out from the nozzle is about 30 to 40% of the amount of air required in standard incineration conditions, and the stirring blades and stirring hands are cooled. The remaining air is kept constant within a range that does not impair the effectiveness, and the remaining air is evenly blown out over the entire hearth from a number of nozzle holes provided at the bottom of the hearth, making the combustion of the materials to be incinerated more stable. This is a further increase in efficiency.

Hereinafter, the present invention will be specifically explained based on illustrated embodiments.

Reference numeral 1 in the figure is a circular incinerator body, which has an exhaust port 2 formed at the top and a number of nozzle holes 4 at the bottom 3 of the furnace, which will be described later into the furnace. A low oxygen concentration exhaust gas or a mixture of this and fresh air is blown into the furnace, and a hearth 5 is formed by spreading sand to an appropriate thickness at the bottom of the furnace. Furthermore, a rotating shaft 6 is erected in the center of the furnace bottom, and two or more stirring doors 7 are radially attached to the top of the rotating shaft 6, and each stirring blade 7 has a large number of stirring hands 8 projecting downward. It is set up. The stirring hand 8 stirs the material to be incinerated placed on the hearth 5 to improve contact with air, and also blows air against the material to be incinerated to promote combustion. The rotary shaft 6, the stirring blades 7, and the stirring hand 8 are all hollow and conductive to each other.A blower 9 is connected to the rotating shaft 6, and the stirring hand 8
A large number of blowholes 10 are bored in the side of the tank, from which a certain amount of air is spouted out.

In addition, the low oxygen concentration exhaust gas discharged from the exhaust port 2 is once led to the heat exchanger 11 and cooled appropriately, and then a part is released into the atmosphere, and the other part is mixed with an appropriate amount of fresh air. It is guided into the nozzle hole 4 and supplied into the furnace.

When operating the circular stirring incinerator constructed in this way, approximately one-third of the amount of air required for standard combustion was supplied by blowing it out from the stirring hand 8, and the remaining air was cooled. The low oxygen concentration exhaust gas is mixed with an appropriate amount of air depending on the combustion conditions in the furnace, and then supplied through the nozzle hole 4.

As described in detail above, the present invention blows out a certain amount of air from the nozzle 10, and the remaining air is supplied from the nozzle hole 4 at the bottom of the furnace after adjusting the oxygen concentration, and has the following effects. There is.

1 By keeping the amount of air blown from the stirring hand 8 constant, the velocity of air flowing through the rotating shaft 6, stirring blades 7, and stirring hand 8 becomes constant, and the cooling effect of these is kept uniform, thereby preventing damage due to overheating. Less is. Since the jetting speed of air from the nozzle port 10 can be made appropriate, generation of clinker and unevenness of the incineration combustion zone can be prevented, and stable incineration operation can be performed.

2 The air supplied from the nozzle hole 4 is mixed with cooled low oxygen concentration exhaust gas or fresh air to adjust the oxygen concentration, and the amount of input material to be incinerated, moisture content, ash layer temperature, combustion gas temperature, exhaust gas Since it detects temperature, etc. and adjusts the supply amount and supplies it from the entire surface of the hearth, it cools the combustion surface and prevents clinker generation, suppresses rapid temperature rise in the primary combustion zone, and reduces oxygen concentration in the high temperature section. Therefore, the generation of _NOx can be suppressed.

3. By fluidizing the ash layer or sand layer with the air ejected from the nozzle hole 4, it is possible to obtain the same incineration effect as a fluidized bed incinerator, and even irregularly shaped lumps can be crushed by stirring with the stirring hand 8. This makes it possible to incinerate high-moisture sludge that is difficult to treat in a fluidized incinerator, such as high-moisture sludge that is difficult to treat with a dehydrator.

[Brief explanation of drawings]

The figure is a schematic diagram showing one embodiment of the present invention. 1... Incinerator body, 2... Exhaust port, 3... Furnace bottom surface, 4... Nozzle hole, 5... Hearth, 6... Rotating shaft, 7... Stirring blade, 8... Stirring hand, 9 ... Blower, 10 ... Fumarole, 11 ... Heat exchanger.

Claims (1)

[Scope of Claims] 1. A hollow rotating shaft is erected in the center of the furnace, several hollow stirring blades are attached radially to the top of the shaft, and the stirring blades are further equipped with several stirring hands with blowholes perforated therein. hanging down,
In a method of incinerating materials to be incinerated using a circular stirring incinerator with a large number of nozzle holes in the bottom of the furnace, about one-third of the required amount of air is ejected from the nozzle, and the amount of air is lower than that of the nozzle hole. Adjust the oxygen concentration and air volume in the furnace by blowing out oxygen-concentrated exhaust gas or gas mixed with an appropriate amount of fresh air,
An incineration method in a circular stirring incinerator characterized by suppressing combustion.