JPH02213609A - Fuel spreading feeder for fluidized-bed boiler - Google Patents

Abstract

PURPOSE:To spread highly moistened residue over the interface of a fluidized bed evenly and efficiently in feeding by providing a spreader having a rotor on whose circumferential surface are provided a plurality of zigzag blades at a specified pitch circumferentially and by providing over the spreader a fuel feed pipe having a laterally long outlet. CONSTITUTION:At the part of a sidewall of a fluidized bed facing a primary- combustion space 21 is installed a fuel spreading feeder 27 comprising a spreader 47, an air box 40, and a fuel feed pipe 43. Highly moistened residue 30 sent from a low-pressure pump is fed to the spreader 47 evenly from the fuel feed pipe 43 having an oblong forward end and spread over the interface of a fluidized bed; the spread is regulated by blades 45 each of which has, for example, zigzag edge and is fixed to a rotor 44 axially and each at an equal pitch from an adjacent blade. The rotor 44 is of an adjustable speed type so that by changing the speed of its revolution the range to which the blades 45 spread fuel over the interface of the fluidized bed is adjusted according to the kind of the fuel.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to coffee grounds, mandarin orange grounds, and beer grounds.

This product relates to a fuel dispersion supply device for a fluidized bed boiler that supplies fuel to the combustion bed in a fluidized bed boiler when high water content residue for waste containing high water content such as tea and sludge or coal is burned. Yes - [Conventional technology] Conventionally, when supplying highly water-containing residue to a fluidized bed combustion bed, ■ a sludge conveyor equipped with a rotatably screw with a fixed pitch inside the casing, and By combining a spreader with a rotor mounted on the sludge conveyor and having rotors arranged radially at regular intervals in the circumferential direction, the highly water-containing residue discharged from the sludge conveyor is first transferred to the next spreader. A method of dispersing and supplying the fuel over the interface of the combustion bed by driving the fuel, and ■ Dispersing the highly water-containing residue discharged by a high-pressure pump onto the interface of the combustion bed using a sludge gun at the tip of the fuel supply pipe installed on the side wall of the fluidized bed. There are ways to supply it.

[Problems to be Solved by the Invention] However, when attempting to supply a highly water-containing residue into the fluidized bed using the above-described combination of the sludge conveyor and spreader, the rotational axis direction of the sludge conveyor and the rotational axis direction of the spreader become misaligned. Because they are perpendicular to each other, the highly water-containing residue pushed out from the discharge side of the sludge conveyor is dispersed in the direction of the rotary axis of the spreader rotor, making it difficult to supply evenly. Because the cloth does not have much diameter and has a high free water content, it is difficult to distribute and supply it evenly to the fluid interface. Therefore, the highly water-containing residue discharged from the spreader remains in an agglomerated state on the fluid interface. This has disadvantages, such as the fact that unburned fuel losses tend to increase as the fuel is supplied to the

In addition, when the high-pressure pump according to the above method (2) is used to distribute and supply highly water-containing residue to the interface of the combustion bed using a sludge gun, the pump power becomes large and running costs increase. .

[Means for Solving the Problems] In order to solve these problems, the present invention provides a spreader installed in the primary combustion space of the side wall of the fluidized bed.
A plurality of blades having the same uneven shape are provided on the outer periphery of the rotor of the spreader at a predetermined pitch in the circumferential direction of the rotor,
Furthermore, a fuel supply pipe having a horizontally long discharge port is disposed above the spreader.

[Function] The present invention aims to provide a combustion dispersion supply device capable of distributing and supplying highly water-containing residues such as beer grounds, coffee grounds, and sludge to a fluidized bed bed using a sprayer 2 da.

First, highly water-containing residue was evenly distributed and supplied from the tip of a fuel supply pipe that had a horizontally long discharge port in the axial direction of the rotor of the spreader, and was supplied to the spreader that had uneven blades attached to the rotor. In this case, since the blade has a shape with heights in the radial direction of the rotor, the circumferential speed varies along the vicinity of the blade tip, and,
When the rotational speed of the rotor exceeds a certain level, the highly water-containing residue supplied from the fuel supply pipe to the spreader collides only near the tips of the blades. Therefore, the circumferential speed is high at the uneven peaks at the tip of the blade, while the circumferential speed is small at the uneven valleys, and furthermore, the circumferential speed decreases as you go from the peaks to the valleys along the uneven shape. Since it changes naturally and continuously, the discharge distance of the highly water-containing residue varies depending on the difference in peripheral speed, and the highly water-containing residue is efficiently and evenly distributed and supplied onto the fluid interface.

[Example] Next, an embodiment of the present invention will be explained using drawings. All drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram showing the overall configuration of a fluidized bed boiler. FIG. 2 is a cross-sectional view taken along the line II--II in FIG. 1.

The configuration of this device will be described using FIGS. 1 and 2.

The apparatus shown in Figure 1 is comprised of a wave bed boiler 1, an air chamber 2 at the lowest stage, a primary combustion chamber 3 at the upper stage. Furthermore, the upper secondary combustion chamber 4, air introduction vibes 5, 5a, partition plates 6.6 &, fluid heat medium 8.9. Burner for auxiliary combustion 10. Combustion and fluidization air inlet 11. It is composed of water cooling pipes 13, 13a, an air box 40, a fuel supply pipe 43°, and a spreader 47.

That is, in this embodiment, two tiered beds are provided as a multi-tiered bed.

Here, a case will be described in which a highly water-containing residue is burned.

A burner 10 for auxiliary combustion is provided on the side of the air chamber 2 and faces inward in the horizontal direction, and a spreader 4 is provided in the primary combustion chamber 3 by burning heavy oil or gas fuel.
7 assists in the drying and combustion of the highly water-containing residue 30 supplied to the primary combustion bed 20, and it is possible to maintain the inside of the primary combustion chamber 3 at a desired temperature. Reference numeral 11 denotes an inlet for air for combustion and fluidization, which allows an appropriate amount of air to be supplied into the air chamber 2 after being heated by a heat exchanger (not shown) using exhaust gas discharged from the top outlet 35 of the fluidized bed. I made it.

The primary combustion chamber 3 consists of a primary combustion bed 20 containing a fluid heat transfer medium 8 made of general sand with an average particle size of about 0.6 mm, and a primary combustion space 21 above the bed 20. A horizontal partition plate 6 is provided between the chamber 2 and the primary combustion chamber 3 located immediately above the air chamber 2, and is disposed vertically through a large number of air introduction pipes 5. , Castables 12 are installed in the upper part (primary combustion chamber side) and lower part (air chamber #) of the partition plate 6 in the form of embedding the water-cooled pipe 13 provided in the partition plate 6, and similarly, the secondary combustion chamber side Similarly to the primary combustion chamber, castables 12a were installed at the upper and lower parts of the partition plate 6a. A spreader 47.
A fuel distribution supply device consisting of an air box 40 and a fuel supply pipe 43 was provided. The combustion dispersion supply device 27 includes an air box 40
．． Fuel supply pipe 43. The highly water-containing residue 30 sent from a low-pressure pump (not shown) consisting of a spreader 47 is
The fuel is evenly supplied to the spreader 47 from a fuel supply pipe 43 having a rectangular tip, and is fixed in the axial direction of the rotor 44 at equal pitches on the circumference of the rotor 44, for example, by blades 45 having a sawtooth shape. , is supplied onto the fluid interface while adjusting the spreading distance. Note that the rotor 44 is of a variable speed type, and the blade 4 changes depending on the rotation speed of the rotor 44.
The structure is such that the discharge distance of the fuel that is injected from No. 5 and reaches the fluid interface can be adjusted depending on the type of fuel. In addition, especially when the high water content residue 30 is dumped onto the fluid interface by the spreader 47, some of the high water content residue 30 is in the immediate vicinity of the spreader 47, that is,
It falls onto the dead space between the side wall of the primary combustion chamber 3 and the spreader 47, and is deposited and deposited on the spreader 47.
In order to prevent continuous combustion from being impeded onto the fluid interface, an air box 40 having a slit or perforated plate for air blowing is provided at the dead space, and air is continuously blown through the slit or perforated plate. The structure is such that the highly water-containing residue 30 is ejected from the perforated plate to prevent adhesion and deposition due to adhesion. In this way, the highly water-containing residue 30 distributed and supplied onto the fluid interface from the spreader 47 mixes with the fluid heat medium 8, and is dried and burned in a fluidized state by the action of the air supplied from the air chamber 2. Ru. here,
Reference numeral 32 indicates a cap provided on the top of each air introduction pipe 5.

Sand is used as the fluid heat medium 8 in the primary combustion chamber 3 because sand has a certain large heat capacity, even if the highly water-containing residue 30 is placed in the combustion bed 20.

This is because the temperature of the combustion bed 20 can be easily maintained,
In addition, in the fluidized state, the stirring effect uniformly disperses the residue 30, scrapes off the ash produced by combustion, and improves the efficiency of contact with oxygen, so it has the effect of improving combustion. .

The primary combustion space 21 and the primary combustion bed 20 of the primary combustion chamber 3
An appropriate number of temperature detectors 31 are installed inside the primary combustion chamber 3, and the detected temperature is measured and the supplied auxiliary fuel is appropriately controlled based on the measured signal to control the temperature and combustion state within the primary combustion chamber 3. It is possible to maintain the desired state at all times.

Between the primary combustion chamber 3 and the secondary combustion chamber 4 located immediately above the primary combustion chamber 3, there is a partition plate having a large number of vertically penetrating air introduction pipes 5a and a water cooling pipe 13a inside. 6a is provided. However, in the air introduction pipe 5a, not only the combustion gas in the lower stage rises and passes through, but also a part of the residue 30 that is being burned in the primary combustion chamber 3 is introduced into the secondary combustion chamber 4.

In the upper secondary combustion chamber 4, 33 is a cap provided at the top of each air introduction pipe 5a, 22 is a secondary combustion bed having a fluid heat medium 9 such as sand, and 23 is an upper secondary combustion space.

Circulating water introduced via a circulation pump (not shown) is
The circulating water pipe branches into two directions from the middle, and one water channel carries the circulating water heated while passing through the water cooling pipe 13 arranged on the partition plate 6 of the primary combustion chamber 3, and the other channel.

The circulating water heated while passing through the water cooling pipe 13a disposed on the partition plate 6a of the secondary combustion chamber 4 is finally sent to a steam drum (not shown).

Next, the operation of the embodiment of the present invention will be explained.

A fluid heat medium 8.9 such as general sand is placed in the primary combustion chamber 3 and the secondary combustion chamber 4, respectively. Next, the lower auxiliary combustion burner 10 is ignited to perform both combustion and fluidization. Combustion and air fluidization air is supplied from the air inlet 11, and the fluid heat carriers 8 and 9 are made to flow, respectively, to form a primary combustion bed 20 and a secondary combustion bed 22.

The highly water-containing residue 30 is then supplied into the primary combustion bed 20 from a nozzle portion 46 at the tip of the fuel supply pipe 43 onto a spreader 47 through a fuel supply pipe 43 by driving a relatively low-pressure pump (not shown). When the primary combustion bed 20
Evenly distributed supply and combustion.

Here, the high water content residue 30 refers to one containing, for example, 60% or more of water, and for example, the above-mentioned residue 3
The normal moisture content at 0 is about 60-7 for coffee grounds.
0%, mandarin orange lees, beer lees.

Approximately 70-90% for oolong tea, approximately 70-8 for sludge
It is 0%.

In the primary combustion bed 20, the residue 30 is dried by the action of the auxiliary combustion burner IO and the combustion heat of the residue 30 itself, and then combusted. In order to simultaneously dry and burn the residue 30 in the primary combustion bed 20, the temperature here is maintained at about aOO to 900°C.

In the apparatus of the invention, in the primary combustion bed 20, the highly water-containing residue 30 is combusted, for example, by about 60% after drying. Then, in the primary combustion space 21, for example, only about 10% is burned, and the unburned matter is not completely combusted in the primary combustion chamber 3, for example, about 3%.
The small piece residue 30 containing 0% is fed into the upper secondary combustion chamber 4.

The remaining residue 30 is subsequently burned in the secondary combustion bed 22 and secondary combustion space 23 of the secondary combustion chamber 4, where it is completely combusted. In addition, in order to burn nearly 100% of the highly water-containing residue 30 in the primary combustion chamber 3, the exhaust flow rate of the exhaust gas after combustion needs to be slowed down to, for example, one-fourth of that in the case of the present invention. Therefore, it is necessary to increase the area of the fluidized bed 2 accordingly, and it is necessary to increase the size of the entire apparatus. It is also necessary to find a special fluid heat transfer medium that fluidizes at a slow flow rate.

By using a compact device like the present invention, the primary combustion chamber 3
If only about 70% of the highly water-containing residue 30 is dried and combusted, a large amount of unburned matter will be produced and the combustion effect will be reduced.However, in the present invention, the remaining combustible residue is subsequently combusted in the secondary combustion chamber 3. The combustion efficiency is very high because complete combustion occurs in the secondary combustion chamber 4. Furthermore, in this device, complete combustion occurs in the secondary combustion chamber 4, so there is very little generation of unburned matter, and the residue 30 is a component. Only the amount of ash that comes out is close to the amount of ash it contains.

After the residue 30 is completely combusted up to the secondary combustion chamber 4, the combustion exhaust gas is discharged from the fluidized bed top outlet 35 and reaches the waste heat boiler. On the other hand, the circulating water sent out by the circulation pump cools the partition plates 6 and 6a of the primary combustion chamber 3 and the secondary combustion chamber 4, and then flows through the water cooling pipe 13.13a disposed inside the primary combustion bed 20. It is preheated by exchanging heat with combustion exhaust gas, and finally supplied to the waste heat boiler. In this way, in the waste heat boiler, heat exchange occurs between the combustion exhaust gas discharged from the fluidized bed top outlet 35 and the steam-mixed saturated water sent via each water cooling pipe, and it is possible to effectively recover it as low-pressure steam. can.

In the above embodiments, two combustion chambers each having a combustion bed and a combustion space are provided. This is a multi-stage combustion apparatus equipped with a fluidized bed that combusts the residue of stages or more stages.

Furthermore, according to the spreader 47 of the present invention, by changing the rotation speed of the rotor 44, the initial speed of the fuel such as the highly water-containing residue 30 can be determined in the same manner as in conventional spreaders. The characteristics of the serrated blades 45 allow the horizontal distance that the fuel can reach to be increased, making it possible to distribute the fuel more evenly. Furthermore, the pitch of the sawtooth is determined by the physical properties of the material to be supplied. In other words, the number of ridges on the serrated blade 44 described above increases when the moisture content is high.
That is, if the internal friction angle is large, replace the rotor 44 with a large pitch of the crests, and conversely, if the moisture content is low, that is, if the internal friction angle is small, simply replace the rotor 44 with the small pitch of the crests. Often, this can be easily dealt with depending on the type of fuel.

Thus, in the embodiment of the present invention, the high water content residual liquid 3
It is easy to disperse and supply materials such as 0, which are difficult to disperse and supply on the fluid interface, so they can be sufficiently dried and
This will increase the combustion efficiency.

[Effects of the Invention] In the fuel dispersion supply device of the present invention, since the blades that are attached to the rotor of the spreader are serrated, the circumferential speed gradually increases as the blades move from the troughs to the crests along the serration shape. This makes it easy to supply highly water-containing residues and solid fuels such as coal in an evenly distributed manner by injecting them into the fluid interface. In addition, if you want to increase the flexibility of fuel injection, you can make the rotation of the spreader rotor variable speed or change the pitch of the sawtooth to uniformly distribute the fuel onto the fluid interface regardless of the type of fuel. is possible.

[Brief explanation of the drawing]

Each of the drawings shows one embodiment of the present invention, and FIG. 1 is a schematic cross-sectional view showing the overall structure of a fluidized bed boiler, and FIG. 2 is a view taken in the nn direction of FIG. Show the diagram. 1... Fluidized bed boiler, 2... Air chamber, 3... Primary combustion chamber, 4... Secondary combustion chamber. 5.5a...Air introduction pipe, 6.6a...
...Partition plate, 8.9...Fluid heat medium, 10...
...Burner for auxiliary combustion. 11...Air inlet for combustion and fluidization, 13.
13a...Water cooling pipe, 27...Combustion distribution supply device, 40...Air box, 43...Fuel supply pipe, 47...Spreader. Patent applicant: Ube Industries, Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) In a spreader installed in the primary combustion space of the side wall of the fluidized bed, a plurality of blades having the same uneven shape are provided on the outer periphery of the rotor of the spreader at a predetermined pitch in the circumferential direction of the rotor. Fuel distribution supply device for fluidized bed boiler. (2) In the spreader installed in the primary combustion space on the side wall of the fluidized bed, a plurality of blades having the same uneven shape are provided on the outer periphery of the rotor of the spreader at a predetermined pitch in the circumferential direction of the rotor, and further, above the spreader. 2. The fuel dispersion supply device for a fluidized bed boiler according to claim 1, further comprising a fuel supply pipe having a horizontally long discharge port disposed at a position.