JP2530502B2 - Highly efficient combustion method and apparatus for fluidized bed furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-efficiency combustion method in a fluidized bed furnace in which the oxygen concentration in the furnace is controlled to a substantially constant concentration to completely combust the treated material in the furnace. It is related to equipment and is suitable for use in the treatment of coal, municipal solid waste, sludge, general waste, etc. that can be burned in a fluidized bed.

[Conventional technology]

Conventionally, the combustion method in a fluidized bed furnace is generally one in which the amount of secondary air for combustion is controlled in accordance with load fluctuations, composition and property fluctuations of the processed material. For example, the amount of secondary air is adjusted by a signal from a thermometer or an O ₂ meter provided in the exhaust gas line at the furnace outlet.

Further, JP-A-59-195019 discloses that primary air is supplied to an air box and secondary air is supplied to a freeboard, and the supply amount of the secondary air for combustion supplied to the primary air and the freeboard is exhaust gas. Describes a fluidized bed combustion furnace which is controlled by the oxygen concentration.

JP-A-60-238605 discloses that air is sent to an oxygen-enriched module, oxygen-enriched air with an increased oxygen concentration is mixed with primary air by a vacuum pump and sent to an air chamber, and
A fluidized bed furnace is described in which oxygen enriched air is supplied to the upper end of the bed. In this way, Japanese Patent Laid-Open No. 60-2386
Japanese Patent Publication No. 05 describes that oxygen-enriched air is supplied to the primary air and oxygen-enriched air is supplied to the upper end of the bed.

[Problems to be Solved by the Invention]

However, in the conventional method of adjusting the amount of secondary air, in the case of a processed material in which load fluctuation, composition and property fluctuation of the processed material are large, incomplete combustion may occur only by controlling the secondary air. It causes smoke.

Further, in the fluidized bed combustion furnace described in JP-A-59-195019, the flow rates of the primary air and the secondary air are adjusted based on the oxygen concentration, but oxygen is not supplied to the primary air or the secondary air. Therefore, the control of O ₂ concentration in the furnace was delayed and stable O ₂ control in the furnace was not possible, resulting in poor combustion efficiency.

The fluidized bed furnace described in Japanese Patent Application Laid-Open No. 60-238605 supplies oxygen-enriched air, but lacks a means for accurately controlling the accurate supply amount thereof, resulting in poor combustion efficiency. Further, in the fluidized bed furnace described in JP-A-60-238605,
The oxygen-enriched air is supplied into the oxygen concentration rare-bed layer at the upper end of the bed section, and is configured to accelerate the combustion of waste in the bed section. Nothing is said about "burning completely".

The present invention has been made in view of the above points, from the supply amount of the treated material, when necessary for secondary air or the like, by supplying an appropriate amount of oxygen, O ₂ concentration control delay in the furnace It is an object of the present invention to provide a method and an apparatus capable of carrying out highly efficient complete combustion without causing such a situation, and capable of achieving compactness of exhaust gas treatment equipment, ventilation equipment and the like.

[Means and Actions for Solving the Problems] In order to achieve the above-mentioned object, the method of claim 1 uses oxygen in the secondary air for combustion supplied to the freeboard when the processed material is combusted in the fluidized bed furnace. Is supplied, and the oxygen supply amount is controlled by the supply amount of the processed material before a load change occurs in the furnace.

Further, the method of claim 2 supplies oxygen to the primary air and the secondary air for combustion to be supplied to the freeboard when the processed material is burned in the fluidized bed furnace, and the oxygen supply amount of these is supplied to the processed material. It is characterized by controlling before the load change occurs in the furnace.

Further, the apparatus of claim 3 is, as shown in FIGS. 1 and 2, a fluidized bed furnace in which a primary air supply pipe 5 is connected to the wind box 2 and a secondary air supply pipe 6 for combustion is connected to the freeboard 4. 1, the oxygen supply pipe 12 is connected to the secondary air supply pipe 6 for combustion,
An oxygen amount adjusting device 11 is provided in the oxygen supply pipe 12, and the oxygen amount adjusting device 11 and the processed material large amount supply detecting means 22 are connected to each other.

Further, in the fluidized bed furnace 1 in which the primary air supply pipe 5 is connected to the wind box 2 and the secondary air supply pipe 6 for combustion is connected to the freeboard 4, the device of claim 4 is the primary air supply pipe 5 and the secondary air supply pipe for combustion. The oxygen supply pipes 24 and 12 are connected to the next air supply pipe 6, and the oxygen amount control devices 23 and 11 are provided to the oxygen supply pipes 24 and 12, respectively. It is characterized in that the supply detection means 22 is connected.

As oxygen, a gas containing oxygen as a main component such as pure oxygen or oxygen-enriched air is used.

In the apparatus of the present invention, the processing material large amount supply detecting means 22
By detecting an abnormality in the supply amount of the processed material in advance and controlling the oxygen amount adjusting device such as a damper in advance, the O ₂ concentration in the furnace can be constantly controlled.

In Claims 1 and 3, as shown in FIG. 1, oxygen is supplied to the secondary air to stabilize the unburned substances in the treated material and the combustion gas without delay in O ₂ concentration control. Burn it completely.

Further, in claims 2 and 4, as shown in FIG. 3, oxygen is supplied to the primary air and the secondary air to cause an O ₂ concentration control delay in the unburned substances in the processed material and the combustion gas. No, stable and complete combustion.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the shape of the constituent devices described in this embodiment, the relative arrangement thereof, and the like, unless otherwise specified, are not intended to limit the scope of the present invention only to them, and are merely illustrative examples. Only.

Example 1 In FIG. 1, 1 is a fluidized bed furnace having a wind box 2, a fluidized bed 3, and a freeboard 4. A primary air supply pipe 5 is connected to the wind box 2, and a combustion secondary air supply pipe 6 is connected to the freeboard 4. Reference numeral 7 is an air dispersion plate, 8 is a treated material inlet, and 10 is an exhaust gas outlet.

In the fluidized bed furnace 1 configured as described above, the oxygen supply device 13 is connected to the combustion secondary air supply pipe 6 via the oxygen supply pipe 12 provided with the oxygen amount adjusting device 11 such as a damper, a valve and an inverter. It is connected. The oxygen supply device 13 is an oxygen cylinder, an oxygen tank, an oxygen production machine, an oxygen-enriched air production machine, or the like. 14 is a primary blower, 15 is a secondary blower, and 18 is a secondary nozzle. In addition, the exhaust gas line is usually provided with a gas cooling chamber and then an electric dust collector.

FIG. 2 shows details of an example of the secondary nozzle 18. A secondary air nozzle 21 is provided so as to cover the oxygen nozzle 20 to form a double tube so that the air and oxygen are mixed and injected into the fluidized bed furnace 1. The oxygen nozzle may be provided so as to cover the secondary air nozzle, or the oxygen nozzle may be provided separately from the secondary air nozzle.

In the high-efficiency combustion apparatus of the fluidized bed furnace configured as described above, the oxygen amount adjusting device 11 such as a damper and the processed material large amount supply detection means 22 for detecting that the processed material is supplied in a larger amount than in the steady state are provided. It is configured to connect and directly detect a large supply of the processed material to control the oxygen amount adjusting device 11 in the opening direction.

The large quantity supply processing means 22 may be, for example, a system that detects the number of revolutions of the processing material supply machine, the weight per unit time, and the volume.

Incidentally, a thermometer 16 or an O ₂ meter 17 is provided in the exhaust gas line, and is connected to the oxygen amount adjusting device 11 to increase the temperature of the exhaust gas by supplying a large amount of the treated material or
It is also possible to detect that the O ₂ concentration decreases and to control the oxygen amount control device 11 in the opening direction, but in the control by only the thermometer 16 or the O ₂ meter 17, in the furnace. O ₂
This is not preferable because a concentration control delay occurs and stable O ₂ concentration control cannot be performed.

Example 2 In this example, as shown in FIG. 3, a secondary air supply pipe 6 for combustion is used.
Also, the primary air supply pipes 5 are connected to oxygen supply pipes 12 and 24 respectively equipped with oxygen amount control devices 11 and 23 such as dampers, and a large amount of processed material supply detection means is connected to these oxygen amount control devices 11 and 23.
22 is connected. Other configurations and operations are similar to those of the first embodiment.

A thermometer 16 or an O ₂ meter 17 is provided in the exhaust gas line and is connected to the oxygen amount adjusting devices 11 and 23 to increase the temperature of the exhaust gas by supplying a large amount of the treated material or O _{2 in the} exhaust gas. Detects the decrease in concentration and adjusts the oxygen content 1
It is also possible to configure so as to control the 1,23 in the opening direction, but the control by only the thermometer 16 or O ₂ meter 17, a stable O ₂ density control occurs O ₂ concentration control delay in the furnace It is not preferable because it cannot be done.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

(1) It is understood that the processing load in the furnace changes several tens of seconds by the means for detecting a large amount of processed material supply, and the oxygen content adjusting device such as a damper is controlled in advance to obtain the O ₂ concentration in the furnace. Can be prevented from changing extremely, and therefore, it is possible to achieve complete combustion of the unburned matter in the treated material and the combustion gas and to perform almost constant O ₂ concentration control.

(2) When burning a treated product with a large variation in composition such as waste, it is possible to supply the required O ₂ accurately and efficiently without delay in O ₂ concentration control. Complete combustion can be carried out.

(3) secondary air by supplying oxygen mixed and stirred, the control content of a small amount of oxygen supply control (eliminates wasteful N ₂ supply during air supply), since O ₂ control can be, the exhaust gas increase and decrease becomes To slight Therefore, the IDF (induction fan) can control the in-furnace pressure stably and reliably, and energy can be saved.

(4) Equipment such as exhaust gas treatment equipment and ventilation equipment (combustion equipment in the case of claims 2 and 4) becomes compact, and initial cost becomes low.

(5) In the case of claims 2 and 4, since the diameter of the fluidized bed furnace can be made small, the air volume of the primary blower, which requires the most power in the fluidized bed, can be reduced. Therefore, it becomes possible to realize energy saving, further downsizing of the downstream exhaust gas facility, and increase in size on the basis of throughput.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a high-efficiency combustion apparatus for a fluidized bed furnace according to the present invention, FIG. 2 is an enlarged sectional view showing an example of a secondary nozzle portion in FIG. 1, and FIG. FIG. 7 is an explanatory view showing another embodiment of the device of FIG. 1 ... fluidized bed furnace, 2 ... wind box, 3 ... fluidized bed, 4 ... free board, 5 ... primary air supply pipe, 6 ... combustion secondary air supply pipe, 7 ... air dispersion plate , 8 …… Processed material inlet,
10 ... Exhaust gas outlet, 11 ... Oxygen control device, 12 ... Oxygen supply pipe, 13 ... Oxygen supply device, 14 ... Primary blower, 15 ...
… Secondary blower, 16… Thermometer, 17… O ₂ meter, 18… Secondary nozzle, 20… Oxygen nozzle, 21… Secondary air nozzle, 22
... Means for supplying a large amount of processed material, 23 ... Oxygen amount adjusting device,
24 ... Oxygen supply pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuyuki Shimokawa 2-5-25 Tenjinbashi, Kita-ku, Osaka City, Osaka Prefecture Kawasaki Heavy Industries, Ltd. Osaka Design Office (56) References Japanese Patent Laid-Open No. 59-195019 A) Japanese Patent Laid-Open No. 60-238605 (JP, A) Actually developed 51-31376 (JP, U) Japanese Patent Publication No. 60-57523 (JP, B1)

Claims (4)

(57) [Claims] 1. When burning a processed material in a fluidized bed furnace, oxygen is supplied to secondary air for combustion supplied to a freeboard,
A highly efficient combustion method for a fluidized bed furnace, wherein the oxygen supply amount is controlled by the supply amount of a processed material before a load change occurs in the furnace. 2. When burning a processed material in a fluidized bed furnace, oxygen is supplied to the primary air and the secondary air for combustion supplied to the freeboard, and the oxygen supply amount in the furnace is controlled by the supplied quantity of the processed material. A highly efficient combustion method for a fluidized bed furnace, which is characterized by controlling before a load change occurs. 3. A fluidized bed furnace (1) comprising a wind box (2) connected to a primary air supply pipe (5) and a freeboard (4) connected to a combustion secondary air supply pipe (6). An oxygen supply pipe (12) is connected to the next air supply pipe (6), an oxygen amount adjusting device (11) is provided in the oxygen supply pipe (12), and the oxygen amount adjusting device (11) and a large amount of processed material are detected. A high-efficiency combustion device for a fluidized bed furnace, characterized in that it is connected to means (22). 4. A primary air supply in a fluidized bed furnace (1) in which a primary air supply pipe (5) is connected to a wind box (2) and a secondary air supply pipe (6) for combustion is connected to a freeboard (4). The oxygen supply pipes (24) and (12) are connected to the pipe (5) and the combustion secondary air supply pipe (6), respectively, and these oxygen supply pipes (24) and (12) are connected.
(12) is provided with oxygen amount adjusting devices (23) and (11), respectively, and these oxygen amount adjusting devices (23) and (11) are connected to a large quantity supply processing object detection means (22). High efficiency combustion equipment for fluidized bed furnace.