JPS6218820Y2 - - Google Patents

Description

[Detailed description of the invention] This invention incorporates a system that protects the stoker and prevents NOX generation, and also economically removes acidic components (HCl, SOx, etc.) from exhaust gas by using alkaline components in the incineration ash. It concerns the Dagomi incinerator.

As an incinerator for municipal waste, for example, one having a structure as shown in FIG. 1 is commonly used. That is, in FIG. 1, the materials 3 to be burned are put into the incinerator 1 from the hopper 2, and after being pushed into the incinerator one by one by the pusher 4 etc., they are passed over the grate 5 into the drying zone A, the combustion zone B, and the like. While moving through the post-combustion zone C, it is dried and burned by the flame from the burner 6. Most of the incinerated ash is discharged from the rearmost ash removal drum 8, and a portion is discharged through the ash chute 9 provided below the fire grate 5, but in any case, the water-sealed ash collection tank 10 let it fall. Ash collection tank 10
The incineration ash accumulated in the ash is carried out of the system by a scraping conveyor 21. The air G supplied to such an incinerator is usually preheated to 100 to 300°C, then sent into the furnace from the side wall of the chute 9 through the supply duct 11, and blown upward from the lower surface of the grate 5. It flows upward and penetrates the three layers of combustible material. After combustion, the gas becomes exhaust gas, which reaches the secondary combustion chamber 20 through the flue 12, and after completely combusting the unburned components, is discharged through the exhaust gas treatment equipment 13.

By the way, the municipal waste treated as described above includes a variety of miscellaneous wastes such as kitchen waste containing a large amount of moisture, plastics, and rubber in addition to combustible materials such as wood and paper. For this reason, overall, it not only generates a lot of soot, which has poor combustibility and is incompletely combusted, but also generates acidic components such as HCl and SOx derived from plastics, rubber, etc., and burner fuel (heavy oil). Occur.

On the other hand, the exhaust gas is often introduced into a heat exchanger and used for preheating the waste combustion air G mentioned above. However, as mentioned above, there are HCl and SOx in the exhaust gas.
Because it contains acidic components (corrosive gases) such as, the heat exchanger and flue, which are the flow paths for the acidic components, are corroded, causing damage. Therefore, since the exhaust gas discharged from the flue 12 contains a large amount of such acidic components, it is necessary to install exhaust gas treatment equipment to remove the acidic components.

By the way, as a method for removing the above-mentioned acidic components, a method of contacting with a caustic soda solution and absorbing and removing them is commonly used, but this method basically corresponds to a neutralization treatment. On the other hand, since the incinerated ash discharged from the incinerator contains a large amount of alkaline components, the present inventor thought that the incinerated ash could be used to remove acidic components from exhaust gas. Therefore, we considered blowing exhaust gas into a collection tank containing incinerated ash or spraying water in the collection tank into the flue, but the former method would require large-scale equipment changes, and the latter method would require a water spray nozzle. It is necessary to take measures against clogging, etc., and it turned out that it is difficult to implement any of these measures.

The present invention was developed in light of these circumstances, and it is a waste that can economically remove the acidic components in the exhaust gas by using the alkaline components in the incinerated ash without significantly changing the configuration of the incinerator. The aim is to provide an incinerator. Furthermore, in dry zones, the presence of flames and moisture from the combustion zone tends to damage the grate due to heat cracks, and furthermore, there is a problem in that the temperature in the lower part of the combustion zone increases too much and NOx is easily generated. The present invention attempts to solve these problems as well. Therefore, the waste incinerator of the present invention is a water seal incinerator with a secondary combustion chamber provided in the exhaust gas discharge section, and a steam supply port or a cold air supply port is provided in the side wall of the drying zone, and the bottom of the drying zone is provided with a steam supply port or a cold air supply port in the side wall of the drying zone. The combustion exhaust gas above the dry zone is bubbled into the water of the ash conveyor by forming an air flow from the ash chute into the water of the ash conveyor, and the collected gas after bubbling is discharged via the secondary combustion chamber. There is a gist.

The configuration and effects of the present invention will be explained below based on the drawings, but the following examples are only specific and are not intended to limit the present invention. All additions are within the technical scope of the present invention.

FIG. 2 is an explanatory diagram of the structure of the waste incinerator of the present invention, and corresponds to FIG. 1. FIG. 3 is an explanatory cross-sectional view taken along the line - in FIG. 2. In these figures, reference numeral 15 denotes a supply port for cold air or steam (hereinafter both referred to as cooling gas), which is provided on the furnace side wall 14 across the grate 5 in the drying zone A, and by discharging cooling gas from there. In addition to protecting the drying zone grate from flames to prevent damage, it is desirable that the number of drying zone grate be plural along the direction of waste movement, and the supply port is provided at the bottom of the combustion zone to discharge cooling gas. The combustion zone temperature can be lowered and the generation of NOx can be prevented. It goes without saying that these supply ports 15 are formed at positions higher than the height of the waste piled on the grate. In addition, the preheated air supply pipe 11 is opened to other chutes other than the drying zone, and the preheated air G rises within these chutes, passes through the grate from bottom to top, and is subjected to combustion. The exhaust gas is supplied to the secondary combustion chamber through the incinerator 1 and the flue 12. Preheated air is not supplied to the dry zone. In addition, a gas inlet 16 is provided in the approximate center of the ash chute 9 below the drying zone and opens downward, and the inlet 16 is connected to the ash in the ash storage tank 10 via a pipe line 17 provided outside the ash chute. connected to water. A suction blower 18 is also interposed in the conduit 17.
On the other hand, an umbrella-shaped air bubble collection hood 19 is provided in a part of the ash storage tank 10, and although the opening of the air bubble collection hood 19 is submerged in the water surface, it may be placed directly above the water surface. . and bubble collection hood 1
9 is connected to the secondary combustion chamber 2 via the exhaust gas secondary duct 22.
The air bubbles collected in the air bubble collection hood 19 are sent into the secondary combustion chamber by the suction force of the exhaust gas supply blower 21.

On the other hand, the temperature of the waste input into the drying zone A is raised by the retained heat of the combustion gas flowing from the combustion zone and the atmosphere inside the furnace, and the moisture accompanying the kitchen waste becomes steam and evaporates, and the chlorine-based Plastic decomposes and produces HCl.

By the way, in the dry zone, the gas in the ash chute is forcibly discharged from the suction port in the chute to the outside of the chute by the suction blower 18, so that the pressure is negative. Therefore, unlike the combustion zone and the post-combustion zone, an airflow passing through the grate 5 from above to below is formed. Therefore, the water vapor, HCl, etc. generated as described above are discharged through the supply port 15 drilled in the furnace wall.
It passes through the grate 5 and into the ash chute 9 together with the cooling gas sent from
The ash is discharged into the water of the ash collection tank 10 via the pipe 17. The exhaust gas thus discharged into the collection tank becomes bubbles within the collection tank 10 and comes into contact with the incinerated ash mixed in the water. Due to this contact, the acidic components in the bubbles are neutralized and rise in a bubbling manner, and are finally collected in the bubble collection hood 19 and sent to the feed blower 21.
is sent to the secondary combustion chamber 20 by. That is, the exhaust gas that has passed through the dry grate from top to bottom enters the ash collection tank 10 from the suction port 16 in the ash chute 19 via the suction blower 18, rises while bubbling in the water, and then enters the hood 19. It is captured and sent to the secondary combustion chamber 20 via the feed blower 21. It is then combined with exhaust gas from the normal route for treatment. In the bubble collection hood 19, the supply blower 21 is operated while controlling the water level in the collection hood 19 to prevent liquid from being sucked into the pipe line 22 and to prevent bubbling gas from overflowing from the collection hood. Let's do it.

As mentioned above, the acidic components contained in the exhaust gas are mixed with the alkaline incineration ash in the ash collection tank 10 and neutralized and removed, so the gas sent from the bubble collection hood to the secondary combustion chamber contains acidic components. It contains almost no components, reducing the risk of corrosion in exhaust gas treatment equipment. Also, by utilizing the heat retained in the combustion exhaust gas from combustion zone B, it is no longer necessary to push fresh heated air from the dry zone, which reduces the amount of gas and allows the design capacity of ancillary equipment (pipes, etc.) to be reduced. . In other words, in the past, the cooling gas that was blown in to cool the furnace wall was sent into the secondary combustion chamber along with the hot air blown up from the lower part of the drying zone, resulting in a large amount of exhaust gas, but in this invention, the cooling gas is kept as it is. By introducing this system, we stopped blowing up hot air from the dry zone, and succeeded in reducing the amount of exhaust gas accordingly.

The basic structure of the present invention is as described above, but in addition, as mentioned above, a cold air or steam inlet is provided not only in the drying zone but also in the combustion zone, and acidic components generated in the combustion zone are also sucked downward. , it is possible to improve the removal efficiency of acidic components by contacting with incineration ash. Furthermore, although the above explanation did not mention anything about the shape or style of the grate, the present invention can be applied to any type of grate commonly used in incinerator equipment such as swinging staircase type, fan-shaped swinging type, reciprocating staircase type, etc. Can be applied. Furthermore, in the example, the airflow from the ash chute to the water of the ash conveyor was formed by providing a side pipe in the ash chute and arranging a suction blower in the side pipe, but the invention is not limited to such a configuration. For example, it is also possible to extend the end of the ash chute to a position below the bubble collection hood and blow the exhaust gas directly into the water using a blower installed in the ash chute.

Since the present invention is structured as outlined above,
It exhibits the effects summarized below.

(1) By using the incineration ash accumulated in the ash collection tank, the acidic components in the exhaust gas can be effectively treated, and the exhaust gas treatment equipment can be downsized accordingly.

(2) Since the exhaust gas from which most of the acidic components have been removed can be used to preheat the intake air, corrosion or wear caused by the exhaust gas can be minimized.

(3) Since the amount of fresh air forced into the dry zone is reduced, the total amount of exhaust gas can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a conventional incinerator, Fig. 2 is an explanatory diagram of the configuration of an incinerator according to the present invention, and Fig. 3 is a schematic explanatory diagram of a conventional incinerator.
It is a - line cross-sectional explanatory view in a figure. 1...Incinerator, 2...Hopper, 3...Waste, 5...Grate, 9...Ash chute, 10...
Water-sealed ash storage tank, 11... Supply pipe, 12... Flue, 14... Side furnace wall, 16... Inlet, 18...
...Suction blower, 20...Secondary combustion chamber.

Claims (1)

[Scope of utility model registration request] In a water seal incinerator with a secondary combustion chamber provided in the exhaust gas discharge section, a steam supply port or a cold air supply port is provided on the side wall of the drying zone, and the airflow from the ash chute at the bottom of the drying zone to the water of the ash conveyor is provided. A garbage incinerator characterized in that the combustion exhaust gas above the drying zone is bubbled into the water of the ash conveyor, and the recovered gas after bubbling is discharged via a secondary combustion chamber.