JPS599157Y2 - Sludge incinerator - Google Patents

Description

[Detailed description of the invention] This invention relates to an improvement of a sludge incinerator for incinerating sludge-like sludge discharged in the final process of purifying sewage, organic wastewater, etc.

Sludge discharged in the final process of purifying sewage and organic wastewater is a liquid with a high solid content.

This liquid sludge is treated to remove the water content using a dehydrator or the like, and is made into a solid sludge cake.However, even this dehydrated sludge cake after dewatering still contains a large amount of water, so it must be disposed of. is accompanied by difficulties.

If this dehydrated sludge cake is left unattended, it will emit a foul odor and the sewage contained therein will ooze out.

For this reason, this dehydrated sludge cake has conventionally been used as fertilizer or disposed of in landfills, but these disposal methods are subject to various restrictions, so alternative methods such as incineration are not recommended. Methods that allow all processing to be completed on-site have begun to be adopted.

However, as mentioned above, the sludge cake after dehydration still contains a large amount of water, so it is extremely difficult to bring it into combustion unless it is first dried.

Furthermore, this dehydrated sludge cake has fine particles and poor air permeability, so it is not easy to dry.

However, even when burned in incineration, the dry dehydrated sludge cake has a low specific gravity and low calorific value, so the combustion temperature is low and it is not possible to obtain high and sustainable thermal power, which is an extremely disadvantageous condition for incineration. There are many.

Therefore, special incineration methods and incineration equipment are required to incinerate the sludge cake.

The purpose of this invention is to provide a rational sludge incinerator that meets the characteristics of the dewatered sludge cake described above.

Hereinafter, this invention will be specifically explained based on drawings showing embodiments thereof.

In Fig. 1, A is an incinerator made of heat-resistant material such as bricks, which has an almost vertical primary drying chamber 1 and a secondary drying chamber that connects to the bottom of this drying chamber and extends diagonally downward. It is equipped with a drying chamber 2 and a combustion chamber 3 extending almost horizontally and communicating with the lower part of the drying chamber, and the upper furnace wall forming the primary drying chamber 1 is equipped with a dehydrated sludge cake. A supply inlet 4 as well as a gas outlet 5 are provided.

The supply port 4 is provided with a member (not shown), such as a rotary damper, to prevent gas from flowing therefrom.

Inside the primary drying chamber 1, a large number of rotating shelves 6 are arranged in a staggered manner from the upper part to the lower part.

The spindle 7a of each rotary shelf 6 is supported on the oven wall, and the shelves from the top to the bottom are successively and intermittently tilted by a suitable drive device.

That is, the dehydrated sludge cake supplied from the supply port 4 is first dropped onto the top shelf 6, and then when it is tilted, it is dropped onto the next shelf 6, and while this is repeated, it is dried. It has become.

Therefore, the upper end of the slope 7 of the oven wall forming the secondary drying chamber 2 of the lowermost shelf 6 is placed close to the upper end of the slope 7 of the furnace wall, and the tilting of the shelf 6 causes the sludge cake on the shelf to move towards the slope 7. It is designed to be dropped at the top end.

Inside the combustion chamber 3, an endless movable grate stoker 8 is disposed in a substantially horizontal state, one end of which is close to the lower end of the furnace wall slope 7 defining the secondary drying chamber 2. The furnace wall slope 7 and the movable grate stoker 8 form an obtuse-angled pile portion.

A scraper 9 is provided near the end in the direction of movement of the Storr force, and a burner 10 is provided in the furnace wall portion of the combustion chamber 3.

In the incinerator constructed as described above, the dehydrated sludge cake is incinerated as follows.

First, the dehydrated sludge cake supplied from the supply port 4 to the primary drying chamber 1 of the furnace is first dropped onto the uppermost shelf 6, where it is held for the required time and then moved onto the next shelf 6 by tilting the shelf. be dropped.

In other words, since the rotary shelves from the top to the bottom are sequentially and intermittently tilted, the residence time of the sludge cake due to falling movement in the drying chamber becomes longer, and the sludge cake flows from the combustion chamber 3 through the secondary drying chamber 2. It is thoroughly dried by the hot air sent to it,
The sludge cake on the lowest shelf 6 is dropped toward the upper end of the furnace wall slope 7 in the secondary drying chamber 2 when the sludge cake is tilted.

The sludge introduced from the supply port 4 still has a high moisture content and is likely to adhere to walls, etc., but when it is dried on the multi-tiered shelves as described above, its specific weight becomes small and it becomes non-adhesive. , the sludge that falls from the bottom shelf is considerably dried, and the majority is granulated.

When the thus dried sludge is dropped onto the slope 7, it is spread along the slope, and the lower part of the diffusion reaches the upper surface of the stoker 8.

The sludge dropped on top of this Storring force is combusted while being carried toward the scraper 9 by the Storring force.

However, if the advancing speed of the Storring force is slowed down, the sludge falling from the lowest shelf will be deposited thickly on the slope 7 in the secondary drying chamber, and the layer of sludge deposited on the Storring force will also become thicker.

On the other hand, if the advancing speed of the Storr force is increased, the thickness of the sludge deposited on the slope 7 becomes thinner, and at the same time, the thickness of the sludge deposited on the Storr force also becomes thinner.

The angle of inclination of the slope 7 in the secondary drying chamber is normally 4 to allow the sludge dried in the primary drying chamber to slide down smoothly.
The slope is preferably about 5 to 70 degrees.

The slope 7 of the secondary drying chamber 2 of the incinerator described above plays a very important role in the sludge incineration action.

This type of sludge has a low calorific value per unit volume, is weak against the force of continuous combustion, and easily disappears. Therefore, in the case of combustion, it is preferable that the sludge accumulates thickly.

Therefore, the stoker 8 is operated at a low speed so that a suitable amount of sludge is deposited thereon and combustion is smooth.

As the thickness of the sludge piled up due to the stow force increases, the thickness of the sludge deposited on the slope 7 in the secondary drying chamber increases accordingly, and as shown in FIG. A condition is created in which sludge is deposited thickly.

Therefore, the sludge on the slope 7 is relatively thin at the upper part of the slope, and is deposited in a thick layer as it reaches the lower part.

On the other hand, the temperature of the combustion gas is highest near the upper part of the stoker 8 in the furnace chamber 3, and this combustion gas rises while drying and igniting the sludge accumulated on the slope 7. Near the bottom, the temperature is lower than the ignition point of the sludge, and as the sludge passes through many shelves, it dries the sludge on each shelf and carries the evaporated water with it to the gas outlet 5.
is discharged from the furnace.

The sludge on the slope 7 is thin at the top and thickens toward the bottom, so that the newly dropped sludge is spread relatively evenly and widely over the sludge layer. Become.

Therefore, the newly dropped sludge is spread thinly and widely along the flow of hot air, and drying is carried out most effectively.

Some of the sludge deposited on the slope 7 reaches the ignition point as it becomes drier, and slow combustion progresses as it reaches the lower part of the slope.

This combustion is more effective and stable when the thickness of the dried sludge pile is relatively thick, and such combustion is very effective in drying the sludge pile layer.

The surface of the sludge deposit layer is given heat by hot air and is dried by hot air, but it is difficult to effectively dry the layer inside the layer.

However, as combustion progresses inside the sludge accumulation layer, combustion heat is generated from inside, and the amount of heat moves along with the combustion gas from the internal combustion part to the layer surface and is supplied as the amount of heat that dries the surrounding sludge. be done.

The layer of accumulated sludge is younger near the surface, and the closer to the inside it is made up of older and drier sludge, so internal combustion of the layer is likely to occur.

In addition, since dried sludge has a low specific gravity and is granular, oxygen for internal combustion is supplied to the interior by diffusion through the gaps between these particles.

In the part where combustion is progressing, the direction of the combustion gas is opposite to the oxygen supply, but the temperature of the oxygen reaching the combustion part is heated by the combustion gas and radiant heat, supplying preheated oxygen, so combustion It is very convenient for

However, although the removal of combustion gas and the supply of oxygen are slow and the combustion speed is relatively slow, this type of combustion is effective for materials that are difficult to burn due to their high moisture content, and this type of reaction is effective in the secondary drying chamber. What is being done on the slope 7 is that not only is the necessary amount of drying heat supplied from the inside to the sludge deposited on the upper side to accelerate drying, but also that organic matter is reduced through combustion and The amount of combustion will be reduced.

Further, even if the layer of sludge deposited on the slope 7 becomes thick, if combustion is performed from within, drying in the secondary drying chamber 2 will be carried out smoothly.

The exhaust gas burned inside the sludge accumulation layer from the slope 7 to the stoker 8 may be incompletely combusted, but it exits the layer and mixes with the combustion gas from the stoker 8 and is kept at a high temperature. Complete combustion takes place there, and there is no possibility that unburned gas or incompletely combusted gas will be discharged outside the furnace.

As mentioned above, the slope 7 in the secondary drying chamber is an extremely important part where the five functions of sludge drying, spreading, storage, preheating, and combustion are performed smoothly in conjunction with the stow force.

Since the lower end of the slope 7 of the secondary drying chamber is connected to the stoker 8, the moving speed of the stoker 1 is adjusted to such a speed that the above action on the sludge accumulation layer from the slope to the stowing force is effectively performed. It is something that should be done.

The incinerated ash is scraped off by a scraper 9, dropped into a pit 11, and discharged outside the furnace.

Combustion air in the stoker 8 is supplied from the bottom of the stoker.

Since sludge incineration usually requires the supply of auxiliary fuel, a burner 10 is provided to burn heavy oil, gas, etc.

The rotating shelf 6 in the primary drying chamber 1 can be of any type, such as one with an appropriate convex edge to prevent sludge from spilling from its periphery, or one with a shelf surface curved into a bowl shape.

Furthermore, if the shelves are arranged in multiple rows as shown in FIGS. 2 and 3, the amount of sludge cake incinerated can be increased.

As mentioned above, according to this invention, inside the incinerator,
A rotating shelf is installed vertically to receive the dehydrated sludge cake supplied from above and drop it downward one after another.The lower part of the rotating shelf row receives the dehydrated sludge cake dropped from the rotating shelf and guides it diagonally downward. A movable grate is arranged at the bottom of the inclined wall and extends in a substantially horizontal direction, and an obtuse-angled zone is defined by the grate and the inclined wall. Since this is considered to be a cake accumulation area, the sludge undergoes a primary drying process in the process of being sequentially dropped on the rotating shelf, and then is dried on an obtuse-angled wall formed by an inclined wall surface and a movable grate. Because it falls and accumulates in some areas and undergoes drying, spraying, storage, preheating, and combustion processes, it is highly effective in incinerating dehydrated sludge cakes that are subject to extremely disadvantageous conditions for incineration. This method can greatly contribute to this type of sludge incineration treatment.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of an incinerator showing one embodiment of this invention, and FIGS. 2 and 3 are longitudinal sectional side views of an incinerator showing other embodiments. In the drawing, A is an incinerator, 1 is a primary drying chamber, 2 is a secondary drying chamber, 3 is a combustion chamber, 4 is a dehydrated sludge supply port, 5 is a gas outlet, 6 is a rotating shelf, and 7 is an inclined wall surface. , 8 is a movable grate stove, 9 is a scraper, 10 is a burner, and 11 is a pit.

Claims (1)

[Scope of utility model registration request] Inside the incinerator, a rotating shelf is installed vertically that receives the dehydrated sludge cake supplied from above and drops it downward one after another.The lower part of the row of rotating shelves receives the dehydrated sludge cake that is dropped from the rotating shelf. An obtuse angle formed by the grate and the inclined wall is formed at the bottom of the inclined wall, and a movable grate that extends in a substantially horizontal direction is disposed in connection with the lower part of the inclined wall. A sludge incinerator characterized in that a shaped zone is used as a cake accumulation area.