JPS60251309A - Fluidized-bed incinerator and method of operating same - Google Patents

Abstract

PURPOSE:To improve the disposal ability of the incinerator up to the transfer to a steady operation and to reduce the amount of auxiliary fuel to be used by supplying the auxiliary fuel from an upper auxiliary fuel supply source at the time of starting incineration and switching it to a lower auxiliary fuel supply system at the time point where the temperature of a free board portion is stabilized. CONSTITUTION:In operating the incinerator, auxiliary fuel O is supplied from an upper supply pipe 18. At a time point where the free board portion assumes a predetermined temperature, charging of sludges S is started, and then immediately switched to blowing-in from a lower supply pipe 19. In this case, the lower supply pipe 19 is located at a position just above the dispersion member on a porous plate 2. The position of the upper supply pipe 18 is not limited as long as it is located at a position higher than the position of the lower supply pipe 19.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a fluidized bed incinerator for sludge cake and the like and a method of operating the same.

[Technical background of the invention and its problems] In recent years, fluidized bed incinerators have been frequently used to incinerate sludge.

Figure 3 shows a typical example. That is, a dispersion plate 2 is provided in the furnace main body l, the upper part of which is preloaded with a fluidized medium 3 such as sand, and the fluidized medium 3 is fluidized by the air A blown in through the air supply chamber 4 at the lower part. A fluidized bed M is formed. Sludge S is fed onto the fluidized bed by a feeder 5.

In this type of fluidized bed furnace, auxiliary fuel O such as heavy oil is injected into the fluidized bed M to facilitate combustion.

In this case, as shown in FIG. 3, conventionally, the blowing pipe 50 is provided at the lower part of the fluidized bed M, for example, at a position of 400 a++s from the upper surface of the perforated plate 2 when the height of the fluidized bed M is 2000+ m. was. In addition, the supply amount of auxiliary fuel O is
Temperature detector 6 provided in the fluidized bed M and the freeboard section,
7 via the selector 8, the temperature controller 9 controls the rlI control valve 1 provided in the auxiliary fuel supply pipe 1θ.
This is done by adjusting the opening degree of l. 12 is a pump.

This conventional fluidized bed incinerator is operated as follows.

That is, to explain with reference to FIG. 2, first, the supply of auxiliary fuel 0 is started, and the temperature rise of the fluidized bed section and the freeboard section is started. Next, when the fluidized bed temperature rises to the ignition temperature of the sludge, for example about 650°C, sludge S can be introduced, but if the freeboard temperature does not exceed 750°C, the sludge will not be completely combusted, so there will be no unused material in the exhaust gas. Since there is a risk of pollution due to the transfer of harmful substances from combustion, we will continue to raise the temperature further and wait until the temperature of both the fluidized bed section and freeboard section rises to approximately 750℃ or higher before starting to introduce sludge. . In this case, the combustion of sludge raises the freeboard temperature, so if a large amount of sludge is added, the freeboard temperature will rise too much and there is a risk of damage to the furnace body. Wait until the temperature of the fluidized bed section and the freeboard section become stable, and then proceed to the rated amount of input.

However, this not only takes too long to reach the rated amount of input, but also increases the amount of fuel used.
Since the amount of incineration is small, the overall incineration efficiency is poor.

[Object of the Invention] The object of the present invention is to provide a fluidized bed incinerator that solves the above-mentioned conventional problems, improves the incineration processing capacity before transitioning to steady operation, and reduces the amount of auxiliary fuel used. The purpose is to provide operating methods.

[Summary of the Invention] The operating method of the present invention to achieve this object is to supply auxiliary fuel to at least the upper and lower parts of the fluidized bed when operating a fluidized bed incinerator that supplies auxiliary fuel into the furnace. A supply system is provided, and when the incineration operation starts, auxiliary fuel is mainly supplied from the upper auxiliary fuel supply system to raise the temperature of the freeboard section, and when the temperature of the freeboard section reaches a predetermined temperature, the auxiliary fuel is supplied. This is characterized by switching the supply of fuel mainly from the lower auxiliary fuel supply system.

Further, the incinerator of the present invention is a fluidized bed incinerator configured to supply auxiliary fuel into the furnace, and is characterized in that auxiliary fuel supply systems are provided for the upper and lower parts of the fluidized bed, respectively. be.

That is, the present invention is based on the following findings and ideas.

In other words, when auxiliary fuel is injected into the upper part of the fluidized bed, the proportion of combustion in the freeboard part increases compared to when it is injected into the lower part, and the temperature in the freeboard part is mainly increased, causing The temperature of the area does not rise much. On the other hand, when auxiliary fuel is injected into the lower part of the fluidized bed, the temperature of the freeboard part is difficult to rise and contributes exclusively to the temperature rise of the fluidized bed part.

Based on this knowledge, the fluidized bed temperature is approximately 650℃ for sludge input.
In light of the fact that the temperature of the freeboard part of Saritoto must be kept below about 850℃ to prevent damage to the furnace body, first, auxiliary fuel is injected into the upper part of the fluidized bed. Mainly, the temperature of the freeboard section is quickly raised to a temperature that can prevent the generation of harmful substances, the time when sludge starts to be introduced is brought forward, and the injection is switched to the injection from the bottom of the fluidized bed immediately after sludge is introduced. By preventing the temperature of the freeboard section from rising too high and preventing damage to the furnace body, and maintaining the temperature of the fluidized bed section above the temperature required for igniting the input sludge, the sludge can be charged earlier, and Since the risk of body damage is eliminated, it is possible to introduce a large amount of sludge from the beginning, and after the freeboard temperature reaches the specified temperature, even a small amount of auxiliary fuel can be supplied to the fluidized bed. Since the temperature of the parts can be maintained, the use of auxiliary fuel is also reduced.

Specific Examples of the Invention] The present invention will be further explained in detail below with reference to a specific example shown in FIG.

In FIG. 1, parts that are the same as those of the conventional example are given the same reference numerals, and their explanations will be omitted.

Sludge S from the hopper 13 is supplied into the furnace body 1 from the feeder 14 via the conveyor 15.

Reference numeral 16 denotes a sludge supply amount regulator, which adjusts the amount of feeder 14 to be cut out by receiving a signal from a weighing device 41117 such as a conveyor scale.

According to the invention, an upper supply pipe 18 and a lower supply pipe 19 of auxiliary fuel are provided. If necessary, a freeboard section supply pipe 20 is also provided.

Flow path switching and fuel control for each supply pipe 18.19 are performed by control valves 21.11. 22 is an auxiliary valve.

During operation, firstly, auxiliary fuel is supplied from the upper supply pipe 18, and the freeboard section is, for example, approximately 730 to 800'.
When the O1 temperature reaches about 750° C., the introduction of sludge is started, and then the blowing is immediately switched to the lower supply pipe 19.

Here, the lower supply pipe 19 is located directly above a dispersion umbrella (not shown) on the perforated plate 2. The position of the upper supply pipe 18 is not limited as long as it is higher than the position of the lower supply pipe 19; for example, even if it is about 300 mm higher than the lower supply pipe 19, a considerable effect can be seen. However, in general,
A height range of H/3 to H is preferred. In order to hasten the temperature rise of the freeboard section, blowing from the freeboard section supply pipe 20 may also be used.

[Example] Next, the effects of the present invention will be clarified by examples.

Fluidized bed height approx. 200011111 (7) 100T/D
For a fluidized bed furnace of ay (dehydrated cake standard) scale, the lower feed pipe is placed 400 mm above the distribution plate, and the lower feed pipe is placed 300 mm above the distribution plate.
An upper supply pipe was installed at a height of m, and the operation pattern shown in FIG. 2 was carried out.

According to FIG. 2, it can be seen without further explanation that the incineration capacity is significantly improved and the amount of auxiliary fuel used is significantly reduced.

[Effects of the Invention] As described above, the present invention greatly contributes to improving the incineration processing capacity and reducing the amount of auxiliary fuel used.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a specific example of the present invention, FIG. 2 is a comparison diagram of operation patterns between a conventional example and an example of the present invention, and FIG. 3 is a schematic diagram of the conventional example. 3. Fluidized medium 9. Temperature controller 18. Upper supply pipe 19. Lower supply pipe A. Air S. Sludge 0. Auxiliary fuel M. Tsukishima Kikai Co., Ltd. Representative Patent Attorney Yoshihisa Nagai Yo 4H - San I Hime -

Claims (2)

[Claims] (1) When operating a fluidized bed incinerator that supplies auxiliary fuel into the furnace, an auxiliary fuel supply system is provided at least to the upper and lower parts of the fluidized bed, and at the start of incineration operation, the auxiliary fuel is mainly supplied to the upper part. Auxiliary fuel is supplied from the system to raise the temperature of the freeboard section, and when the temperature of the freeboard section reaches a predetermined temperature, the supply of auxiliary fuel is switched mainly to the supply from the lower auxiliary fuel supply system. Features of operating method of fluidized bed incinerator. (2) A fluidized bed incinerator configured to supply auxiliary fuel into the furnace, characterized in that auxiliary fuel supply systems are provided for the upper and lower parts of the fluidized bed, respectively.