JPS59115912A - Incinerating device for object to be incinerated containing large amount of moisture content - Google Patents

Abstract

PURPOSE:To effectively recover not only the sensible heat of exhaust gas but also the condensed latent heat of steam contained in exhaust gas and to improve the coefficient of heat recovery, by a method wherein the interior of the combustion system and the exhaust gas of an incinerating device is maintained in a pressurized condition. CONSTITUTION:Two compressers 19 and 20 are mounted to an air passage 8 for combustion, and two turbine 21 and 22, positioned corresponding to the compressers, are installed to an exhaust gas passage 11. A first heat exchanger 23 for recovering mainly the sensible heat of high temperature exhaust gas exhausted is installed in the vicinity of an exhaust gas outlet 10 of an incinerator, a dust collector 12 and the turbine 21 are located on an exhaust gas passage 11 on the downstream side thereof, and a second heat exchanger 24 for recovering the condensed latent heat of steam contained mainly in exhaust gas is situated on the downstream side thereof. This constitution enables exhaust gas from an incinerator 2 to be heat-exhanged with a heating medium within the first heat exchanger 23 to recover the latent heat. Exhaust gas exhausted from the first heat exchanger 23 is released from part of its pressure through the dust collector 12 and the turbine 21, and is further introduced in the second heat exchanger 24 where the sensible heat of exhaust gas and the condensed latent heat of steam are recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an incinerator for incinerating materials containing a large amount of water, such as sewage sludge, and in particular, the present invention relates to an incineration device for incinerating materials containing a large amount of water, such as sewage sludge, and in particular, it converts not only the sensible heat of combustion exhaust gas but also the latent heat of condensation of water vapor contained therein to a relatively high temperature. The present invention relates to an incinerator that can greatly reduce the amount of auxiliary fuel that is conventionally required by recovering the amount of auxiliary fuel and using it as a heat source for pre-drying the material to be incinerated.

When disposing of industrial waste, agricultural waste, municipal waste, sewage sludge, etc., these wastes are generally incinerated because they can be reduced in volume and made non-polluting. is recovered and used in various ways from the standpoint of effective energy use.

As one of the usage modes, when the material to be incinerated contains a large amount of water, it is necessary to dry it before burning it, and combustion exhaust gas is used as a heat source.

For example, conventional methods include passing high-temperature combustion exhaust gas directly through a drying pit to dry the materials to be incinerated, or first generating steam using the heat of the exhaust gas, and then passing this steam through a drying pit to incinerate the materials. It is designed to dry things.

By the way, in all of the above conventional examples, the heat used for drying is only the sensible heat of the exhaust gas, and a large amount of water vapor contained in the exhaust gas is released as it is without being condensed, and the large amount of latent heat it has is not utilized at all. It was discarded without being disposed of. For this reason, since the material to be incinerated is not sufficiently dried, it cannot be self-combusted, and auxiliary fuel is supplied for combustion, resulting in an inconvenience that running costs rise.

In order to correct this inconvenience, it is possible to condense the water vapor and recover the heat of condensation, but in order to condense the water vapor, heat must be exchanged until the exhaust gas temperature becomes extremely low. This means that the heat exchange equipment will become huge.
Not practical.

In addition, a large amount of air containing the odor of incinerated materials is discharged from the drying pit, but this air often has a bad odor, so a separate deodorizing device must be installed to make this air pollution-free. This led to a rise in equipment costs.

The present invention has focused on the above-mentioned problems and has been devised to effectively solve them.The purpose of the present invention is to pressurize the combustion system and the exhaust gas system to reduce the amount of gas contained in the exhaust gas. By condensing the water vapor, not only the sensible heat of the exhaust gas but also the latent heat of condensation of the water vapor is recovered, thereby greatly reducing the amount of auxiliary fuel required in the past.
An object of the present invention is to provide an incinerator that can reduce running costs.

The present invention provides that water vapor contained in exhaust gas can be easily condensed in a relatively high temperature range by pressurizing the combustion system such as an incinerator and the exhaust gas system that transfers combustion exhaust gas. The goal was to find out.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic system diagram showing a first embodiment of a combustion apparatus according to the present invention.

As shown in the figure, this incinerator includes a drying pit 1 for drying materials to be incinerated containing moisture, an incinerator 2 for incinerating the dried materials to be incinerated, and a pressurized air for pressurizing and supplying combustion air to the incinerator 2. a heat exchanger 4 that recovers sensible heat and latent heat of condensation of water vapor contained therein from the pressurized exhaust gas discharged from the incinerator 2; While releasing the exhaust gas into the atmosphere, the booster 3
It is mainly composed of a turbine 5 that obtains driving force.

Specifically, the drying pit 1 is provided with a heat transfer tube 6 through which the heating medium supplied from the heat exchanger 4 flows, and the material to be incinerated containing a large amount of moisture is put into the pit. The heating medium can be dried by indirect heat exchange between the heating medium and the heating medium. An incineration material transfer passage (transfer means) 7 and a combustion air transfer passage 8 are interposed between this Pyradora and the incinerator 2, respectively, and the dry incineration material is transferred to the incinerator 2 through the inlet. For example, it can be thrown into a screw conveyor 9 provided in the screw conveyor 9. In addition, the external pressure machine 3 is interposed in the combustion air transfer passage 8 described in 2 above, and can pressurize the atmosphere containing the odor of the incinerated material discharged from the pit 1 and supply it as combustion air into the furnace. It looks like this. At this time, the pressure of the combustion air is desirably maintained at approximately 7 atmospheres.

The type of incinerator 2 is not limited, and for example, a fluidized bed incinerator may be used, but in order to maintain the pressure inside the incinerator, it has a closed structure except for the exhaust gas outlet 1o. Therefore, when the material to be incinerated is put into the furnace, it is sealed by, for example, the screw conveyor 9, and when the incineration residue is still discharged from the furnace, it is sealed by the screw conveyor (not shown). This prevents pressure from leaking from the combustion system.

A sealed exhaust gas passage 11 is connected between the exhaust gas outlet 1o of the incinerator 2 and the turbine 5, so that the exhaust gas can be transferred to the turbine side in a pressurized state. There is. This exhaust gas passage 11 is provided with a dust collector 12 for collecting dust in the exhaust gas, and a heat exchanger 13, which is the most distinctive feature of the present invention, on its downstream side. A heating medium, such as water, supplied to the drying pit 1 is circulated through the heat transfer tubes 14 in the heat exchanger 13, and the temperature of the medium is increased by indirect heat exchange between the medium and the exhaust gas. I'm starting to get it. In particular, since the exhaust gas in the heat exchanger 4 is maintained at approximately 7 atmospheres (approximately the same pressure as the pressure boosted by the booster), the condensation temperature of the water vapor contained in this exhaust gas also increases. Therefore, a large amount of condensed water is generated in this, making it possible to recover the latent heat of water vapor. Therefore, a condensed water outlet 15 for discharging condensed water is provided in the casing of the heat exchanger 4 so as to be openable and closable. Note that this discharge port 15 is opened only when necessary, and is of course closed during normal operation to maintain internal pressure.

The rotating shaft 16 of the turbine 5 is directly connected to the rotating shaft of the booster 3, and the rotating force obtained by expanding pressurized exhaust gas to a pressure close to atmospheric pressure is used to drive the booster 3. It can now be used effectively as a power. Note that the rotational shafts of the turbine 5 are not limited to being directly connected to each other, and for example, the armature of a generator may be rotated to generate power as the turbine rotates, and this may be used as the drive source for the booster 3.

Next, the operation of the incinerator constructed as above will be described.

First, the material to be incinerated M stored in the drying pit 1 is transferred from the heat exchanger 4 side and heated and dried by a high-temperature heating medium flowing inside the heat transfer tube 6. At this time, as will be described later, since the amount of heat possessed by this heating medium is very large, the incinerated material M is dried to the extent that it self-combusts, and is then transferred to the incinerator 2 via the incinerated material transfer passage 7. They are sequentially transferred to the screw conveyor 9, sealed, and sequentially put into the furnace.

On the other hand, the atmosphere (air) containing the odor of incinerated materials discharged from the pit 1 as it dries is sucked into the combustion air passage 8, and is pumped to about 7 atm by a booster 3 installed in this passage. The pressure is increased to the front and back and the air is supplied into the incinerator 2 as combustion air.

After this combustion air is heated by an air preheater 17 using exhaust gas as a heat source, it is injected into the furnace 2 while forming, for example, a fluidized bed to incinerate the materials to be incinerated that are introduced from the screw conveyor 9 side. At this time, since the material to be incinerated has been sufficiently dried, it will self-combust without supplying auxiliary fuel. Furthermore, since this combustion system is sealed, pressure does not leak to the outside, and the pressurized state within this system is maintained. The exhaust gas generated in the furnace 2 is heated and expanded, and flows through the exhaust gas passage 11 through the exhaust gas outlet 10 at an accelerated rate. After the dust 18 is removed from this highly pressurized exhaust gas in the dust collector 10, it is further introduced into the heat exchanger 4, where it indirectly exchanges heat with the heating medium flowing inside the heat transfer tube 14. This causes the heating medium of the lever to rise in temperature. In particular, during this heat exchange, not only can the sensible heat of the exhaust gas be recovered, but also the exhaust gas is maintained in a pressurized state and the condensation temperature of the water vapor contained in it is raised. ), the water vapor that could not be condensed will be condensed, and therefore the latent heat of condensation of the water vapor can also be recovered. As a result, the heat recovery rate is dramatically improved compared to the conventional method, and as mentioned above, the incineration material can be sufficiently dried to the point where it can self-combust.

On the other hand, the exhaust gas discharged from the heat exchanger 4 is introduced into the turbine 5 while maintaining a pressurized state, where it is expanded to a pressure close to atmospheric pressure and released into the atmosphere. The driving force is effectively used as a driving force for the booster 3 via the rotating shaft 16 as it is.

In addition, the bad odor emitted by the burnt materials contained in the combustion air is thermally decomposed in the incinerator 2, so there is no bad odor in the exhaust gas that is finally released into the atmosphere, which is not necessary in the past. There is no need to install a deodorizing device.

Next, a second embodiment of the present invention will be described based on FIG.

Components that are the same as those in the first embodiment are given the same reference numerals and explanations will be omitted.

This second embodiment takes into consideration the heat balance of the entire device, and as shown in the figure, two boosters 19 and 20 are provided in the combustion air passage 8, and two boosters 19 and 20 are also provided in the exhaust gas passage 11 correspondingly. turbines 21 and 22 are provided.

First, a first heat exchanger 23 is provided near the incinerator exhaust gas outlet 10 to mainly recover the sensible heat of the exhaust gas, and a dust collector 12 is installed in the downstream exhaust gas passage 11. and a turbine 21, and a second heat exchanger 24 for recovering the latent heat of condensation of water vapor mainly contained in the exhaust gas is provided on the downstream side thereof.

With this configuration, the exhaust gas from the incinerator 2 is first heat exchanged with a heating medium in the first heat exchanger 23, and sensible heat is recovered. Here, since the heating medium introduced has been heated to a certain degree in advance in the second heat exchanger 24, almost no water vapor is condensed in the first heat exchanger 23, or even if it is condensed, it is only a small amount. .

The exhaust gas discharged from the first heat exchanger 23 releases a part of its pressure via the dust collector 12 and the turbine 21, and is further introduced into the second heat exchanger 24, where it is introduced into the first heat exchanger 24. As in the embodiment, sensible heat of exhaust gas and latent heat of condensation of water vapor are recovered. Note that during this time, the exhaust gas is of course maintained in a pressurized state.

The exhaust gas discharged from this second heat exchanger 24 is transferred to the downstream turbine 22, from which it is expanded and released into the atmosphere.

In this way, by considering the heat balance of the entire device, it is possible to further improve the heat recovery efficiency and further increase the driving force obtained from the turbine.

Note that the number of heat exchangers etc. mentioned above is not limited,
The quantity of each of these devices will be selected to optimize the heat balance of the entire device.

In summary, according to the present invention, the following excellent effects can be achieved.

(1) Since the combustion system and exhaust gas system of the incinerator are maintained in a pressurized state, not only the sensible heat of the exhaust gas but also the latent heat of condensation of the water vapor contained in the exhaust gas can be effectively recovered, improving the heat recovery rate. can be done.

(2) Therefore, the recovered heat can be used to dry the incineration material containing a large amount of water to the point where it can self-combust, making it possible to eliminate the need for auxiliary fuel, which is conventionally required.

(3) Expansion energy when pressurized exhaust gas is released into the atmosphere can be effectively used as the driving force for the booster, so the drive energy for the booster is not separately required, or even if it is needed, it can be done in a small amount. Can be done.

- (4) Due to the reasons (2) and (3) above, the running cost of the combustion device can be significantly reduced.

(5)? f, Since the material to be incinerated can be dried to the extent that it can self-combust, the dehydration process before incineration can be simplified.

(6) Since all of the air containing bad odors emitted from the incinerated material is used as combustion air, the deodorizing equipment that was conventionally required can be eliminated, which helps reduce equipment costs.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram showing a first embodiment of an incinerator according to the present invention, and FIG. 2 is a schematic system diagram showing a second embodiment. In the figure, 1 is a drying pit, 2 is an incinerator, and 3°19.2
0 is a booster, 4, 23.24 is a heat exchanger, 5.21.2
2 is a turbine, M is a material to be incinerated, and A is an atmosphere containing the odor of a material to be incinerated (combustion air). Patent Applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinutani Figure 2

Claims (1)

[Claims] A drying pit for drying the incinerated material, and a drying pit for drying the incinerated material, in an incineration apparatus that indirectly heats the incinerated material containing a relatively large amount of water with a heating medium and incinerates the dried incinerated material, and the pit an incinerator that combusts the incinerated material dried in the pit in a closed state; a booster that increases the pressure of the atmosphere containing the odor of the incinerated material discharged from the pit and supplies it to the incinerator as combustion air; A heat exchanger that indirectly exchanges heat between the exhaust gas discharged from the furnace and the heating medium and also recovers the heat of condensation of water vapor in the exhaust gas to raise the temperature of the heating medium, and a heating medium discharged from the heat exchanger. An apparatus for incinerating materials containing a large amount of moisture, characterized by comprising a turbine for obtaining driving force for the booster while discharging pressurized exhaust gas into the atmosphere.