JP3874454B2 - Waste incineration equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a waste incineration facility equipped with a catalyst packed tower, and more particularly to a means for recovering the activity of the catalyst packed in the catalyst packed tower as needed.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a waste incineration facility equipped with a catalyst packed tower for treating nitrogen oxides and dioxins in exhaust gas. In general boiler exhaust gas treatment, the catalyst is often used in a temperature range of 300 to 400 ° C., which exhibits good activity. However, in exhaust gas treatment of a waste incinerator, (1) because dust is highly poisonous. It is necessary to provide a bag filter in front of the catalyst packed tower, and in order to remove hydrogen chloride and dust with the bag filter, the exhaust gas temperature must be cooled to 150 to 200 ° C. It is usually difficult to heat to 300 ° C or higher at all times. (2) Dioxins are generated or regenerated in the flue space when the catalyst is used at 300 to 400 ° C. Used in the temperature range of.
[0003]
By the way, in a refuse incinerator that burns waste whose fuel properties are unstable, incomplete combustion is occasionally generated, and unburned matter including oil is projected and generated. In addition, even when combustion is performed well, dioxins and oils composed of chlorobenzenes, chlorophenols and other aromatic hydrocarbons at concentrations several hundred times the dioxin concentration are present in the furnace exhaust gas, and there is no Never become. Most of these oils have a boiling point of 350 ° C. or lower.
[0004]
As the catalyst packed in the catalyst packed tower, a catalyst in which fine pores are developed on the surface and inside to increase the internal surface area to obtain high activity is used. For example, a titanium oxide-based catalyst has several micropores developed so that ammonia for denitrification, nitrogen oxide to be treated, and dioxin are adsorbed and reacted on a large internal surface realized by this. It has become. Therefore, the highly active catalyst used in the temperature range of 200 to 300 ° C. is also well adsorbed with oils composed of aromatic hydrocarbons similar to dioxins.
[0005]
When the amount of oil adsorbed by the catalyst is small, the oil is decomposed on the catalyst and released into the gas, so that it does not accumulate on the catalyst. However, if the amount of oil adsorbed becomes larger than the amount of oil to be decomposed due to a temporary decrease in the temperature of the catalyst or a temporary increase in the oil concentration in the exhaust gas, or the amount of adsorbed tar content that is not decomposed increases. The fine pores of the catalyst are blocked, or the surface of the fine pores is coated to reduce the catalytic activity. In the worst case, the catalyst is deactivated. Further, if the amount of oil adsorbed on the catalyst increases in this way, the oil adsorbed on the catalyst is likely to spontaneously ignite, which may cause damage to the catalyst.
[0006]
[Problems to be solved by the invention]
In the conventional waste incineration equipment, no consideration is given to removing the oil adsorbed on the catalyst, and there is a disadvantage that the catalyst life is short.
The present invention has been made to solve the disadvantages of the prior art, and the problem is that a waste incineration facility equipped with a catalyst packed tower capable of maintaining good catalyst performance over a long period of time. Is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a waste incinerator and a catalyst filling for treating nitrogen oxides and dioxins in the exhaust gas by bringing the exhaust gas generated in the waste incinerator into contact with a catalyst at a temperature of 300 ° C. or lower. met waste incineration system and a tower, a catalyst wherein the catalyst-packed tower catalyst packed in heated from time to time 350 ° C. or higher to decompose the oil that is absorbed to the catalyst, to recover the activity of the catalyst In the case where a heating means is provided, as the catalyst heating means, a heating gas obtained by continuously introducing air into the waste incinerator after the refuse supply is stopped and heating the air with the residual heat of the waste incinerator. and the configuration of Ru with a heating gas inlet pipe from time to time introduced into the catalyst-packed column.
[0008]
As described above, since most of the oil contained in the exhaust gas has a boiling point of 350 ° C. or lower, if the catalyst in the catalyst packed tower is heated to 350 ° C. or higher, the oil adsorbed on the catalyst is vaporized. Can be removed from the catalyst surface. When the oil component is removed from the catalyst surface, the catalyst surface having a large area due to the fine pores is cleaned and exposed, so that the activity of the catalyst can be recovered. Moreover, since it becomes difficult to cause spontaneous ignition, damage to the catalyst due to overheating is also prevented. Furthermore, when air is continuously introduced into the waste incinerator after the supply of the waste is stopped and the air is heated with the residual heat of the waste incinerator, a heated gas of 350 ° C. or higher that is much cleaner than the combustion exhaust gas is obtained. Therefore, according to this means, the catalytic activity can be recovered by using this heated exhaust gas without providing any other special heat source.
[0010]
Note that even if the catalyst is heated, not all of the oil adsorbed on the catalyst is oxidized, so it is necessary to treat the oil desorbed from the catalyst. As a means for this, the desorbed gas was introduced through the de Chakugasu discharge pipe, it is possible to take measures that includes an adsorption tower for harmless adsorbed on the adsorbent. According to this means , since the desorption gas is adsorbed by the adsorbent such as activated carbon, the oil removal efficiency can be increased.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a waste incineration facility according to the present invention. In this figure, 1 is a waste incinerator, 2 is a cooling tower that adjusts the exhaust gas temperature of the waste incinerator 1, 3 is a bag filter that removes dust and acid gas in the exhaust gas, and 4 is nitrogen oxides and dioxins in the exhaust gas. The catalyst packed tower 5 removes the exhaust gas and the like, 5 is a blower that sucks the exhaust gas and releases it to the atmosphere, 6 is an adsorption tower filled with an adsorbent such as activated carbon, 7 is the suction of the desorbed gas generated in the catalyst packed etc. 4 The blower introduced into the adsorption tower 6 is shown.
[0012]
The exhaust gas generated in the waste incinerator 1 is introduced into the cooling tower 2 through the exhaust gas flue 11 and is cooled to about 200 ° C. by recovering waste heat or spraying water. The cooled exhaust gas is added with slaked lime for hydrogen chloride treatment supplied from the slaked lime supply pipe 13 in the bag filter inlet flue 12 and introduced into the bag filter 3 to remove acid gases such as hydrogen chloride and dust. The The exhaust gas that has passed through the bag filter 3 is added with ammonia supplied from the ammonia supply pipe 15 in the flue 14 at the inlet of the catalyst packed tower, and reduction and removal of nitrogen oxides and decomposition of dioxin are performed in the catalyst packed tower 4. The exhaust gas that has passed through the catalyst packed tower 4 is sucked into the blower 5 and discharged into the atmosphere through the catalyst packed tower outlet flue 16 and the atmospheric discharge pipe 17. The configuration so far is not different from the conventionally known municipal waste incineration facilities.
[0013]
The features of the present invention are as follows. (1) Heated gas for introducing air heated by the residual heat of the waste incinerator 1 into the catalyst packed tower 4 via the exhaust gas flue 11 and heating the catalyst to 350 ° C. or higher. (2) equipped with an adsorption tower (6) for introducing the desorption gas generated in the catalyst packed tower (4) through the desorption gas discharge pipe (23) and adsorbing and removing the oil in the desorption gas; 3 ▼ The gas flowing into the catalyst packed tower inlet flue 14 via the exhaust gas flue 11, the cooling tower 2, the bag filter inlet flue 12, and the bag filter 3 during the catalyst heat treatment bypasses the catalyst packed tower 4 and is directly catalysted. This is because a bypass flue 22 flowing to the packed tower outlet flue 16 is provided.
[0014]
The waste incinerator 1 includes a waste supply pipe 41 for supplying the waste pressure fed from a waste supply machine (not shown) into the waste incinerator 1 and a flow for fluidizing and burning the waste in the furnace to supply the air into the furnace. An air pipe 42 is provided. If the supply of the fluid air from the fluid air pipe 42 is continued even after the supply of the dust from the waste supply pipe 41 is stopped, the fluid air is heated to 350 ° C. or more by the residual heat of the waste incinerator 1 and is more than the combustion exhaust gas. A remarkably clean heated gas is generated. Accordingly, the on-off valves 32 and 33 provided in the catalyst packed tower inlet flue 14 and the catalyst packed tower outlet flue 16 are closed, and the on-off valves 34 and 31 provided in the bypass flue 22 and the heated gas introduction pipe 21 are opened. Then, the heated gas cooled by the cooling tower 2 and passed through the bag filter 4 is discharged into the atmosphere through the bypass flue 22 and the atmospheric discharge pipe 17 and introduced into the heated gas introduction pipe 21 from the exhaust gas flue 11. The high-temperature heated gas is directly introduced into the catalyst packed tower 4.
[0015]
The catalyst in the catalyst packed tower 4 is heated to 350 ° C. or higher by the high-temperature heated gas introduced into the catalyst packed tower 4. As described above, since most of the boiling point of the oil adsorbed on the catalyst is 350 ° C. or less, most of the oil adsorbed on the catalyst by this heat treatment is decomposed and removed from the catalyst. As a result, the activity of the catalyst is recovered, and spontaneous ignition of the oil adsorbed on the catalyst is also prevented. The desorption gas generated in the catalyst packed tower 4 is sucked by the blower 7 and introduced into the adsorption tower 6 through the desorption gas discharge pipe 23. The adsorption tower 6 is filled with an adsorbent such as activated carbon, and the oil in the desorption gas is adsorbed by the adsorbent and removed. The gas after the adsorption processing is sucked by the blower 7 and introduced into the atmospheric discharge pipe 17 through the processing gas discharge pipe 24.
[0016]
Since the waste incineration facility of this example uses the residual heat of the waste incinerator 1 as a heat source for heat-treating the catalyst, it does not require a special heat source for catalyst heat-treatment, and the structure is simple and can be implemented at low cost. There are features. Further, since the desorption gas generated in the catalyst packed tower 4 is introduced into the adsorption tower 6 and subjected to the adsorption treatment, there is a feature that the effect of cleaning the desorption gas is high.
[0017]
FIG. 2 shows a first reference example of the waste incineration facility according to the present invention. In this figure, 51 is an electrothermal air heater, 52 is a heated air introduction pipe for introducing heated air generated by the electrothermal air heater 51 into the catalyst packed tower 4, 53 is an on-off valve provided in the heated air introduction pipe 52, Reference numeral 54 denotes a desorption gas discharge pipe for introducing the desorption gas generated in the catalyst packed tower 4 into the refuse incinerator 1, 55 denotes a blower provided in the desorption gas discharge pipe 54, and other parts corresponding to FIG. Is displayed with the same symbol.
[0018]
As is apparent from this figure, the waste incineration facility of this example is characterized by using an electrothermal air heater 51 as a heat source for heat-treating the catalyst. In the heat treatment of the catalyst, the open / close valves 32 and 33 provided in the catalyst packed tower inlet flue 14 and the catalyst packed tower outlet flue 16 are closed with the electrothermal air heater 51 activated, and the heated air introduction pipe 52 is connected. The provided on-off valve 53 is opened. As a result, the air heated by the electrothermal air heater 51 is introduced into the catalyst packed tower 4 through the heated air introduction pipe 52 , and the catalyst in the catalyst packed tower 4 is heated to 350 ° C. or higher and adsorbed on the catalyst. The removed oil is removed. Further, the desorption gas generated in the catalyst packed tower 4 is sucked by the blower 55 and introduced into the garbage incinerator 1 through the desorption gas carry-out pipe 54 and incinerated in the garbage incinerator 1 to be rendered harmless. Since the other portions are the same as waste incineration facility according to implementation embodiments, the description thereof is omitted to avoid duplication.
[0019]
Since the waste incineration facility of this example heats the catalyst with the heated air generated by the electrothermal air heater 51, the catalyst can be heat-treated at any time while continuously performing the waste incineration treatment in the waste incinerator 1. There is a feature that can be done. Further, since the desorption gas generated in the catalyst packed tower 4 is introduced into the refuse incinerator 1 and incinerated, it does not require a special desorption gas processing apparatus such as an adsorption tower and can be implemented at low cost.
[0020]
FIG. 3 shows a second reference example of the waste incineration facility according to the present invention. In this figure, 51 is an electrothermal air heater, 52 is a heated air introduction pipe for introducing the heated air generated by the electrothermal air heater 51 into the catalyst packed tower 4, and 53 is an on-off valve provided in the heated air introduction pipe 52. The other parts corresponding to those in FIG. 1 are indicated by the same reference numerals.
[0021]
As is clear from this figure, the waste incineration facility of this example is characterized in that an electrothermal air heater 51 is used as a heat source for heat-treating the catalyst and an adsorption tower 6 is used as a desorption gas processing device. To do. In the heat treatment of the catalyst, the open / close valves 32 and 33 provided in the catalyst packed tower inlet flue 14 and the catalyst packed tower outlet flue 16 are closed with the electrothermal air heater 51 activated, and the heated air introduction pipe 52 is connected. The provided on-off valve 53 is opened. As a result, the air heated by the electrothermal air heater 51 is introduced into the catalyst packed tower 4 through the heated air introduction pipe 52, and the catalyst in the catalyst packed tower 4 is heated to 350 ° C. or higher and adsorbed on the catalyst. The removed oil is removed. Further, the desorption gas generated in the catalyst packed tower 4 is sucked by the blower 7 and introduced into the adsorption tower 6 through the desorption gas discharge pipe 23. Then, the oil in the desorption gas is adsorbed by an adsorbent such as activated carbon and rendered harmless. Since the other portions are the same as waste incineration facility according to implementation embodiments, the description thereof is omitted to avoid duplication.
[0022]
Since the waste incineration facility of this example heats the catalyst with the heated air generated by the electrothermal air heater 51, the catalyst can be heat-treated at any time while continuously performing the waste incineration treatment in the waste incinerator 1. There is a feature that can be done. Further, since the desorption gas generated in the catalyst packed tower 4 is introduced into the adsorption tower 6 and subjected to the adsorption treatment, there is a feature that the effect of cleaning the desorption gas is high.
[0023]
【The invention's effect】
As described above, according to the present invention, after the supply of waste is stopped, air is continuously introduced into the waste incinerator, and the heated gas obtained by heating the air with the residual heat of the waste incinerator is supplied to the catalyst packed tower. Since the waste gas incinerator is equipped with the heated gas introduction pipe introduced as needed, the activity of the catalyst in the catalyst packed tower can be recovered without requiring a special heat source for the catalyst heat treatment.
[Brief description of the drawings]
FIG. 1 is a flowchart of a waste incineration facility according to an embodiment .
FIG. 2 is a flowchart of the waste incineration facility according to the first reference example.
FIG. 3 is a flow diagram of a waste incineration facility according to a second reference example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Waste incinerator 2 Cooling tower 3 Bag filter 4 Catalyst packed tower 5 Blower 6 Adsorption tower 7 Blower 11 Flue gas flue 12 Bag filter inlet flue 13 Slaked lime supply pipe 14 Catalyst packed tower inlet flue 15 Ammonia supply pipe 16 Catalyst packed tower Outlet flue 17 Atmospheric discharge pipe 21 Heated gas introduction pipe 22 Bypass flue 23 Desorption gas discharge pipe 24 Process gas discharge pipe 31, 32, 33, 34 On-off valve 41 Garbage supply pipe 42 Fluid air pipe 51 Electric heating air heater 52 Heating Air introduction pipe 53 On-off valve 54 Desorption gas discharge pipe 55 Blower

Claims (2)

  A waste incineration facility comprising a waste incinerator and a catalyst packed tower for contacting exhaust gas generated in the waste incinerator with a catalyst at a temperature of 300 ° C. or less to treat nitrogen oxides and dioxins in the exhaust gas, The catalyst heating means is provided with a catalyst heating means for heating the catalyst packed in the catalyst packed tower to 350 ° C. or higher as necessary to decompose oil absorbed in the catalyst and recovering the activity of the catalyst. As described above, heating gas introduction that continuously introduces air into the waste incinerator after stopping the waste supply, and introduces the heating gas obtained by heating the air with the residual heat of the waste incinerator to the catalyst packed tower as needed Waste incineration equipment characterized by having a pipe. 2. The waste incineration facility according to claim 1, further comprising an adsorption tower that introduces desorption gas generated from the catalyst packed tower through a desorption gas discharge pipe and adsorbs it to an adsorbent to render it harmless. Waste incineration equipment.

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