JP4056955B2 - Incinerator and its combustion method - Google Patents

Description

  The present invention relates to an incinerator and a combustion method thereof, and more particularly to an incinerator and a combustion method thereof in which a rotary kiln furnace and a stoker furnace are combined.

  As a device that efficiently incinerates miscellaneous waste such as garbage, waste plastic, and oil mud, it consists of a rotary kiln furnace, which is a cylindrical furnace made of steel plate lined with furnace materials, and a stoker furnace installed downstream of the rotary kiln furnace An incinerator is used. This furnace is combusted in the rotary kiln furnace by the primary air supplied with waste, and the combustion residue from the rotary kiln furnace is sent to the stoker furnace where the grate reciprocates back and forth and burns and is ashed. The At the same time, unburned gas generated in the rotary kiln furnace and the stoker furnace is combusted by secondary air supplied separately in the secondary combustion chamber (for example, Patent Documents 1 and 2).

  In such conventional incinerators, the primary air sent to the rotary kiln furnace and the combustibles are not sufficiently mixed and the amount of unburned material increases. Yes. When the rapid combustion occurs, a local high temperature portion may be generated, and NOx is easily generated, which is not preferable.

  Therefore, the inventor of the present application has invented a technique in which a combustion gas circulation path that guides the combustion gas of the stoker furnace to the rotary kiln furnace is provided. In other words, by extracting the combustion gas with a large amount of residual oxygen generated in the stoker furnace with a circulation fan and guiding it to the rotary kiln furnace through the circulation path, it is possible to slow the combustion of the combusted material and make it difficult to generate NOx and the like. Since the amount of primary air supplied to the rotary kiln furnace can be reduced, the amount of exhaust gas can be reduced.

However, in the case of this incinerator, since the combustion gas of the stoker furnace is heated to about 800 ° C., considering the heat resistance of the circulation fan for drawing out, it is necessary to set the temperature to about 300 ° C. or less. It is necessary to install a heat exchanger and cooling equipment to reduce the temperature.
JP-A-9-280524. Japanese Patent Laid-Open No. 11-270821.

  Therefore, the problem to be solved by the present invention is that in an incinerator in which a rotary kiln furnace and a stoker furnace are combined, when extracting and using the combustion gas of the stoker furnace, a heat exchanger for reducing the temperature of the combustion gas, It is an object of the present invention to provide an incinerator and a combustion method thereof that can eliminate cooling equipment and further reduce equipment costs.

The above object can be achieved by the invention described in the claims. That is, the characteristic configuration of the incinerator according to the present invention includes a rotary kiln furnace that burns the combusted material, and a stoker furnace that is connected to the downstream side of the rotary kiln furnace and has a post-combustion stoker and a secondary combustion chamber , burning a combustion residue from the rotary kiln in the post-combustion stoker, combustion gas and unburned gas from the post-combustion stoker and the rotary kiln in the secondary combustion chamber is stirred by blowing air causes combustion In the incinerator ,
Gas extraction means for extracting a high-temperature combustion gas with a large amount of residual oxygen generated in the post-combustion stoker from the post-combustion stoker and introducing it to the front end side of the rotary kiln furnace as a primary air, and mixing the combustion gas and fresh air at a predetermined ratio Mixing means for producing the primary air, temperature measuring means provided on the downstream side of the mixing means or the post-combustion stoker, and on the outlet side of the rotary kiln furnace, and to the rotary kiln furnace based on the measurement result of the temperature measuring means And a control means for controlling the temperature and amount of the primary air .

  According to this configuration, the high-temperature combustion gas extracted by the gas extraction means can be diluted with fresh air and mixed, and the temperature of the mixed gas can be adjusted by setting the mixing ratio to a predetermined ratio. No heat exchanger (economizer, etc.) or cooling equipment is required, and equipment costs and running costs can be reduced.

As a result, incinerators that combine rotary kiln furnaces and stoker furnaces provide an incinerator that eliminates the need for heat exchangers and cooling equipment to extract and use the combustion gas from the stoker furnace, and can further reduce equipment costs. it can. Moreover, it is preferable to introduce the mixed gas of the gas extracted by the gas extraction means and fresh air to the front end side of the rotary kiln furnace. According to this configuration, the combustion gas and air can be fed to the front end side of the rotary kiln furnace through the common line, so that the equipment cost can be reduced.

In addition, it is preferable that a heat exchanger or a cooling facility be provided along with the gas extraction means to increase the amount of combustion gas extracted by the gas extraction means .

Furthermore, it is preferable to introduce the primary air not only into the front end side of the rotary kiln furnace but also into the secondary combustion chamber. According to this configuration, since the combustion gas and air can be fed to the secondary combustion chamber on the front end side of the rotary kiln furnace through the common line, the equipment cost can be reduced.

In addition, the characteristic configuration of the combustion method of the incinerator according to the present invention is that a combustible is burned by a rotary kiln furnace, and is connected to the downstream side of the rotary kiln furnace, and has a post combustion stoker and a secondary combustion chamber. An incinerator that burns the combustion residue from the rotary kiln furnace in the post-combustion stoker and stirs and burns the combustion gas and unburned gas from the rotary kiln furnace and the stoker furnace in the secondary combustion chamber by air blowing. In the combustion method of
A high-temperature combustion gas with a large amount of residual oxygen generated in the post-combustion stoker is extracted by the gas extraction means, and fresh air is mixed with the combustion gas at a predetermined ratio to produce primary air, and the primary air is moved to the front end side of the rotary kiln furnace. And controlling the temperature and amount of the primary air to the rotary kiln furnace according to the temperature of the produced primary air, the downstream side of the post-combustion stoker, and the outlet side of the rotary kiln furnace .

  According to this configuration, an incinerator that combines a rotary kiln furnace and a stalker furnace eliminates the need for heat exchangers and cooling equipment when extracting and using the combustion gas from the stalker furnace, and further reduces the equipment cost. A furnace combustion method can be provided. As a method of mixing fresh air with the extracted combustion gas at a predetermined ratio, a control mechanism may be provided and controlled automatically or manually, or a duct or the like for allowing a predetermined amount to flow may be provided at a predetermined ratio. You may make it mix.

It is preferable to introduce the primary air not only into the front end side of the rotary kiln furnace but also into the secondary combustion chamber.

  According to this configuration, since the combustion gas and air can be fed to the secondary combustion chamber on the front end side of the rotary kiln furnace through the common line, the equipment cost can be reduced.

  It is preferable to control the method of mixing fresh air with the extracted combustion gas at a predetermined ratio, and to control the ratio of mixing the fresh air with the temperature of the mixed gas.

  According to this configuration, it is possible to reliably prevent the gas extraction means such as the circulation fan for extraction from being damaged without increasing the equipment cost.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic overall structure of an incinerator according to the present embodiment. This incinerator is composed of a rotary kiln furnace 1 inclined somewhat toward the downstream side and a stalker furnace 2 connected to the downstream side. The stalker furnace 2 includes a post-combustion stalker 2a, the upper part of which is The secondary combustion chamber 2b has a post combustion stoker 2a and a combustion gas from the rotary kiln furnace 1 joined together and combusted.

  The rotary kiln 1 has a supply device 11 and a start burner 1a on the upstream side (left side in FIG. 1), and introduces a mixed gas of combustion gas and air extracted from the post-combustion stoker 2a as will be described later. It has a mouth 1b. The rotary kiln 1 is rotated slowly by the rotary drive device 12 and burns the combustible material supplied by the supply device 11 while stirring and transports it to the post-combustion stoker 2a. It should be noted that combustibles with poor ignition are appropriately ignited and burned by the start burner 1a. In the post-combustion stoker 2a, the primary air is supplied from the lower part by the primary air supply fan 3, thereby transferring the combustion residue from the rotary kiln furnace 1 while burning it. The combustion residue ashed by the post-combustion stoker 2a is discharged from the ash outlet 10 downstream of the post-combustion stoker 2a.

  The combustion gas Gex generated in the post-combustion stoker 2 a is sucked and discharged outside the furnace by an intake fan 4 that is a gas extraction means, and is introduced from the inlet 1 b at the upstream end of the rotary kiln furnace 1.

  Here, in the present embodiment, the combustion gas Gex extracted by the intake fan 4 and the external fresh air A are introduced and mixed by adjusting the opening of the damper 5a, so that the combustion gas of about 800 ° C. The temperature of Gex is adjusted to be about 170 to 300 ° C. This avoids the high temperature range where the intake fan 4 is likely to corrode and improves the durability of the intake fan 4, as well as heat exchangers (air heaters, economizers, deaeration heaters, etc.) and other Cooling equipment (saturated water spray equipment provided for combustion fluctuations) is not required, and equipment costs and running costs can be reduced. However, it is preferable to provide a heat exchanger and a cooling facility because the amount of combustion gas Gex extracted by the intake fan 4 can be further increased. Thus, even if a corrosive component is contained in the extracted combustion gas Gex, since it is diluted with fresh air A, durability of piping, joints, fans, and other equipment can be improved.

  Therefore, what is introduced as primary air from the inlet 1b at the upstream end of the rotary kiln furnace 1 is a mixed gas G of the combustion gas Gex and air A generated from the post-combustion stoker 2a. The opening of the damper 5a is controlled by a thermometer 6a provided on the outlet side of the intake fan 4, and the extracted combustion gas Gex is constantly extracted so that the temperature of the mixed gas G is in an appropriate temperature range. Air A is mixed at a predetermined ratio.

  Instead of this method, the opening degree of the damper 5a is controlled based on the measurement result of the thermometer 6d that measures the downstream temperature of the post-combustion stoker 2a so that the temperature of the mixed gas G falls within an appropriate temperature range. The extracted combustion gas Gex and air A may be mixed at a predetermined ratio.

  Further, while measuring the temperature on the outlet side of the rotary kiln furnace 1 with the thermometer 6b, the result is used for adjusting the opening degree of the damper 5b for adjusting the primary air supply amount to the post-combustion stoker 2a. The temperature and amount of primary air supplied to the rotary kiln furnace 1 fed by the intake fan 4 by appropriately controlling the combustion state of the stalker 2a and adjusting the opening degree of the damper 5c on the intake fan 4 inlet side. Is preferably controlled.

  In the secondary combustion chamber 2b above the post-combustion stoker 2a, a secondary combustion burner 7 is provided, and a secondary air supply fan 8 for introducing fresh air B through a damper 5d is provided. Burn unburned gas. On the downstream side of the secondary combustion chamber 2b, an exhaust gas treatment facility (not shown) for detoxifying the combustion gas generated from the secondary combustion chamber 2b is connected, and the detoxified exhaust gas is released to the atmosphere.

  A downstream side of the secondary combustion chamber 2b is provided with a thermometer 6c for measuring the temperature of the combustion gas and an oxygen sensor 9 for measuring the oxygen concentration. The former is the result of the secondary combustion in the secondary combustion chamber 2b. The latter is used for controlling the burner 7, and the latter is used for adjusting the opening degree of the damper 5d for adjusting the air amount of the secondary air supply fan 8, or for the damper 5b for adjusting the primary air supply amount to the post-combustion stoker 2a. It is used for adjusting the opening degree and the opening degree of the damper 5c that adjusts the amount of the mixed gas G to the rotary kiln furnace 1, thereby enabling an appropriate operation. Although not shown, these controls can be performed using a separately provided control device. Of course, these controls can be performed automatically, but may be performed manually.

1000 kg of waste plastic is put into the rotary kiln furnace of the incinerator shown in FIG. 1 and burned, transferred to the post-combustion stoker and burned, and the combustion gas Gex 1300 m ³ N / h and external fresh air A 2800 m ³ / h were mixed by adjusting the opening of the damper so as to have a ratio of 1: 2, and a mixed gas G of about 280 ° C. was introduced to the inlet side of the rotary kiln furnace. During this time, the combustibility with respect to the combustibles was good and stable operation was possible, and NOx was 100 ppm or less and could be kept low.

[Another embodiment]
(1) Various types of thermometers can be used as the thermometers 6a, 6b, 6c, and 6d, and are not particularly limited, but elastic scattering obtained by irradiating a laser beam in the furnace is measured. It is preferable to use a laser-type thermometer that measures in this way because it can respond quickly and accurately in real time.
(2) The mixed gas G of the gas Gex and fresh air extracted by the gas extraction means may be introduced not only into the front end side of the rotary kiln furnace but also into the secondary combustion chamber 2b. If it does in this way, combustion gas and secondary air can be supplied with a common line, and equipment cost can be reduced.
(3) In the above embodiment, an example of a furnace in which a stoker furnace provided with a post-combustion stalker is connected to a rotary kiln furnace is shown. However, the present invention can burn combustibles in each of the rotary kiln furnace and the stoker furnace. The present invention can also be applied to a furnace in which the combustion residue from the rotary kiln furnace is post-combusted simultaneously with the combustion residue from the stoker furnace.
(4) In the above embodiment, an example in which nothing is provided on the outer periphery of the body portion of the rotary kiln furnace is shown, but a cooling jacket may be provided on the outer periphery of the body portion of the rotary kiln furnace.

  INDUSTRIAL APPLICABILITY The present invention can be used for incineration of garbage, waste plastic, oil mud, etc., and can be used for incineration of sludge and various solid-liquid mixed waste.

Schematic general block diagram showing an embodiment of an incinerator according to the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary kiln furnace 2 Stoker furnace 2b Secondary combustion chamber 4 Gas extraction means

Claims (5)

A rotary kiln furnace for burning the combustibles, and a stoker furnace connected to the downstream side of the rotary kiln furnace and having a post-combustion stoker and a secondary combustion chamber, and in the post-combustion stoker, combustion residues from the rotary kiln furnace are removed. In an incinerator for burning and stirring the combustion gas and unburned gas from the rotary kiln furnace and the post-combustion stoker by blowing air in the secondary combustion chamber ,
Gas extraction means for extracting a high-temperature combustion gas with a large amount of residual oxygen generated in the post-combustion stoker from the post-combustion stoker and introducing it to the front end side of the rotary kiln furnace as a primary air, and mixing the combustion gas and fresh air at a predetermined ratio Mixing means for producing the primary air, temperature measuring means provided on the downstream side of the mixing means or the post-combustion stoker, and on the outlet side of the rotary kiln furnace, and to the rotary kiln furnace based on the measurement result of the temperature measuring means An incinerator having control means for controlling the temperature and amount of the primary air . The incinerator according to claim 1 , wherein a heat exchanger or a cooling facility is provided along with the gas extraction means to increase the amount of combustion gas extracted by the gas extraction means . The incinerator according to claim 1 or 2 , wherein the primary air is introduced not only into the front end side of the rotary kiln furnace but also into the secondary combustion chamber. The combustion of the combustion product by a rotary kiln furnace, in stoker furnace having a combustion stoker and secondary combustion chamber after being connected to the downstream side of the rotary kiln, cause burning combustion residue from the rotary kiln at the post-combustion stoker In addition, in the combustion method of the incinerator where the combustion gas and the unburned gas from the rotary kiln furnace and the stoker furnace are stirred by air blowing in the secondary combustion chamber and burned,
A high-temperature combustion gas with a large amount of residual oxygen generated in the post-combustion stoker is extracted by the gas extraction means, and fresh air is mixed with the combustion gas at a predetermined ratio to produce primary air, and the primary air is moved to the front end side of the rotary kiln furnace. And the temperature and amount of the primary air to the rotary kiln furnace are controlled by the temperature of the primary air produced, the downstream side of the post-combustion stoker, and the outlet side of the rotary kiln furnace. Incinerator combustion method. The incinerator combustion method according to claim 4 , wherein the primary air is introduced not only into the front end side of the rotary kiln furnace but also into the secondary combustion chamber .

Images