JPH02223719A - Fuel spreading supply device of fluidized bed boiler - Google Patents

Abstract

PURPOSE:To spread and supply a high water content residue widely uniformly by provided a plurality of blades, in which the side shape is bow-form on the periphery of a rotor of a spreader and the front shape allows the outer circumferential end to be in the form of a recess and a projection, at specified pitches in the circumferential direction of the rotor. CONSTITUTION:With regard to parts in which the outer circumferential end of the front shape of blades 45 is in the form of a recess and a projection, in the case of a projection part circumferential speed is large, it continuously becomes small as it is allowed to approach to the recess part of a root by the rotation of a rotor 44 and a release arrival distance is different by different circumferential speed, so a high water content residue 30 is diffusively supplied on a fluidized surface uniformly. Furthermore, after the high water content residue 30 collides with the blades 45 in the case where the side face shape of the blades 45 is in the form of a blow, the residue 30 is released at a large elevation angle because it is released in the tangential direction and nearly right angles of a blade face, so that it can be diffusively supplied on the fluidized face further and uniformly as the whole by two synergetic effects.

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 lees and sludge or coal is burned. be.

[Conventional technology] Conventionally, when supplying highly water-containing residue to a fluidized bed combustion bed, ■ a sludge conveyor equipped with a screw with a fixed pitch rotatably installed inside the casing; By combining the rotor with a spreader having rotors arranged radially at regular intervals in the circumferential direction, the highly water-containing residue discharged from the sludge conveyor is first driven to the next spreader. 1) Disperse and supply 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 methods.

[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 would otherwise be dispersed and evenly supplied to the inlet side of the spreader.

Furthermore, since the highly water-containing residue itself does not have much particle size distribution and has a high free water content, it is difficult to distribute and feed it evenly onto the fluid interface, which causes the highly water-containing residue discharged from the spreader to collect. It has drawbacks such as being fed onto the fluid interface in a lumpy state, which tends to increase unburned loss.

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 problem] In the spreader installed in the primary combustion space of the side wall of the fluidized bed, the outer periphery of the rotor of the spreader has an arcuate side surface shape, and the outer peripheral edge of the front surface shape has an uneven shape. A plurality of blades are provided at a predetermined pitch in the circumferential direction of the rotor.

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

First, highly water-containing residue is uniformly distributed and supplied from the tip of a rectangular fuel supply pipe to the axial direction of the spreader, and the outer peripheral edge of the front face is uneven, and the side face is arched. When a blade is supplied to a spreader that is pivoted to a rotor, due to the rotation of the rotor, the peripheral speed of the convex part at the tip of the former blade is high due to the rotation of the rotor.
Conversely, the circumferential speed decreases continuously as the blade approaches the concave portion at the root of the blade. In this way, the circumferential speed changes continuously from the concave portion to the convex portion along the uneven shape.

Since the ejection distance differs depending on the peripheral speed, the ejection is distributed and supplied evenly onto the fluid interface. In addition, with the latter arcuate shape, the highly water-containing residue supplied from the fuel supply pipe toward the spreader collides with the rotating blade and is released in a direction approximately perpendicular to the tangential direction of the blade surface. The highly hydrated residue will be ejected at a larger elevation angle, and the synergistic effect of these two will collectively result in it being distributed further and more evenly over the fluid interface.

[Example] Next, an embodiment of the present invention will be explained using drawings. All three 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 line H-II in FIG. 1, and FIG. 3 is a side view showing circumferential velocity distribution when the blade of the present invention is used.

The configuration of this device will be described using FIGS. 1, 2, and 3.

The apparatus shown in FIG. 1 includes a fluidized bed boiler 1, an air chamber 2 at the lowest stage, a primary combustion chamber 3 at the upper stage, a secondary combustion chamber 4 at the upper stage, air introduction pipes 5, 5a, a partition plate 6, 6a, fluid heat medium 8.9, auxiliary combustion burner 10, combustion and fluidization air inlet 11. It is composed of a water cooling pipe 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 partition plate 6 is provided horizontally between the chamber 2 and the primary combustion chamber 3 located immediately above the air chamber 2, and a large number of air introduction pipes 5 are disposed through the partition plate 6. are provided in a substantially vertical direction, and furthermore, a water cooling pipe 13 with a castable tube 12 provided in the partition plate 6 is buried in the upper part (primary combustion chamber side) and lower part (air chamber side) of the partition plate 6. Similarly, castables 12a were installed in the upper and lower parts of the partition plate 6a for the secondary combustion chamber 4 as well as for the primary combustion chamber. 1 of the side wall of the fluidized bed
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 evenly supplied to the spreader 47 from a fuel supply pipe 43 having a rectangular tip, and is distributed at equal pitches on the circumference of the rotor 44. and a blade 4 having a sawtooth shape and an arcuate shape fixed in the axial direction.
5, it is supplied onto the fluid interface while adjusting the spraying distance. As shown in FIG. 3, since the vicinity of the tip of the blade 45 has an arcuate shape, the circumferential velocity r of the portion with the radius of curvature r is such that the angle at which the highly water-containing residue 30 is released from the blade 45 is large. As shown in FIG. 4, even if the circumferential velocity V is the same as that of a blade whose entire side surface shape is straight, the blade 45 of the present invention has a longer ejection distance. The quality of the arcuate shape near the tip of the blade 45, in other words, the size of the radius of curvature r, determines the release efficiency of the high water content residue 30 (here, the high water content residue 30 supplied from the fuel supply pipe 43, (indicates the percentage of the liquid applied to the fluid interface by the spreader 47). In other words, generally speaking, as the radius of curvature r increases, the release efficiency increases, but if the discharge distance of the highly water-containing residue 30, which is the fuel, from the spreader 47 is short, and conversely, the radius of curvature r becomes small, the discharge efficiency increases. Although it is smaller, the emission distance is longer and it can be used in large equipment. However, the radius of curvature r is equal to the ratio of the emission efficiency and the emission distance.
According to the test results of the present invention, the ejection distance was considerably longer than that of the blade 45 shown in FIG. 4, which has a straight side profile.

Note that the rotor 44 is of a variable speed type.
The structure is such that the discharge distance of the fuel jetted from the blade 45 and reaching the fluid interface can be adjusted depending on the type of fuel. In addition, especially when the highly water-containing residue 30 is thrown onto the fluid interface by the spreader 47, some of the highly water-containing residue 30 is in the immediate vicinity of the spreader 47, that is, between the side wall of the primary combustion chamber 3 and the spreader 47. In order to prevent this from falling onto the dead space, adhering to it, accumulating it, and preventing it from being continuously projected from the spreader 47 onto the fluid interface, a slit 42 for air blowing or An air box 40 having a perforated plate is provided, and air is continuously blown out through the slits 42 or the perforated plate to prevent the highly water-containing residue 30 from adhering and being deposited.

Here, the highly water-containing residue 30 distributed and supplied onto the fluid interface from the spreader 47 mixes with the wave heating medium 8, and is dried in a fluidized state by the action of the air supplied from the air chamber 2. be burned.

Here, 32 indicates a cap provided on the top of each air introduction pipe 5.

Sand was used as the fluid heat medium 8 in the primary combustion chamber 3 because sand has a certain large heat capacity.

This is because even if the highly water-containing residue 30 is put into the combustion bed 20, the temperature of the combustion bed 20 can be easily maintained, and in a fluidized state, the residue 30 is uniformly dispersed due to its stirring effect, and the combustion This is because it scrapes off the ash produced and improves the efficiency of contact with oxygen, which 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 the negative water channel carries the circulating water heated while passing through the water cooling pipe 13 installed on the partition plate 6 of the primary combustion chamber 3, and the other channel carries the circulating water that is heated while passing through the water cooling pipe 13 installed in the partition plate 6 of the primary combustion chamber 3. 4 partition plate 6a
The circulating water that is heated while passing through the water cooling pipe 13a disposed in the water cooling pipe 13a is finally sent to a steam drum (not shown).

Next, the operation of one 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). Then, due to the shape characteristics of the blades 45 driven by the spreader 47, the fuel is evenly distributed and supplied into the primary combustion bed 20 for 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 to 90% for oolong tea lees, approximately 70 to 8 for sludge
It is 0%.

In the primary combustion bed 20, the residue 30 is dried and then combusted by the action of the auxiliary combustion burner 10 and the combustion heat of the residue 30 itself. In order to simultaneously dry and burn the residue 30 in the primary combustion bed 20, the temperature here is maintained at about 800-900°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 efficiency will decrease. However, in the present invention, the remaining combustion is continued 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 flows through water cooling pipes 13 arranged on the partition plates 6, 6a between the primary combustion chamber 3 and the secondary combustion chamber 4.
．． While passing through 13a, it is heated and sent to a steam drum (not shown). Further, the circulating water sent to the waste heat boiler exchanges heat with the combustion exhaust gas discharged from the fluidized bed top outlet 35 through the conduction pipe, is led to the steam drum, and can be effectively recovered as low-pressure steam.

In the above embodiments, two combustion chambers each having a combustion bed and a combustion space are provided. A multi-stage combustion apparatus is provided with a fluidized bed for combusting the residue 30 of one or more stages.

Also, like coal particles, they are generally low in moisture.

In the case where the coal particles have a particle size distribution, the spreading characteristics are different between large-diameter particles and small-diameter particles among the coal particles to be supplied, and when the relative position of the fuel supply pipe 43 and the spreader 47 cannot be adjusted, the rotor 44 Since the drop position of the fuel is fixed, the horizontal distance reached by the fuel release angle is roughly determined by the law.

Furthermore, according to the spreader 47 of the present invention, by changing the rotation speed of the rotor 44, the initial velocity of the fuel such as the highly water-containing residue 30 can be determined in the same way as with conventional spreaders, and the higher the rotation speed, the more Both the arcuate shape and the characteristics of the gA tooth shaped blades 45 allow for a greater discharge reach and more even distribution of the fuel. moreover,
The number of ridges on the serrated blade 45 described above is such that when the moisture content is high, the pitch of the crests is large, and when the moisture content is low, the pitch of the ridges is small.
Depending on the type of fuel, it can be easily handled by simply replacing the fuel.

Further, the bow-shaped blade 45 having a large degree of arching, that is, one having a small radius of curvature r, is suitable for fuel supply with a high moisture value and a large particle shape. That is, a material with a large radius of curvature r has a low moisture content and is suitable for dispersing and supplying fuel with a small particle size.

Thus, in the embodiments of the present invention, the highly water-containing residue 3
This is because it is easy to disperse and supply materials such as 0 that are difficult to disperse and supply on the fluid interface.

Its molecular nature allows it to be dried and burned, increasing combustion efficiency.

[Effects of the Invention] In the fuel dispersion supply device of the present invention, the blades pivoted on the rotor of the spreader are made into a sawtooth shape and an arcuate shape, so that the characteristics of the sawtooth shape change from the troughs to the peaks along the sawtooth shape. The circumferential speed gradually increases as the blade moves toward the blade surface, making it easy to continuously disperse and supply highly water-containing residue over long distances. Since the discharge is carried out in the right angle direction, the synergistic effect of the characteristic shape of the blade makes it possible to widely and evenly distribute and supply even a small spreader without increasing the rotational speed V very much. In addition, if it is desired to further increase the degree of freedom of combustion, it is possible to uniformly disperse and supply fuel onto the fluid interface by making the rotation of the rotor of the spreader variable.

[Brief explanation of the drawing]

The drawings all show one embodiment of the present invention, and FIG. 1 is a schematic vertical cross-sectional view showing the overall configuration of a fluidized bed boiler, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1. 3 is a side view showing the circumferential velocity distribution when using the blade of the present invention,
FIG. 4 shows a side view showing the circumferential velocity distribution when a conventional blade is used. ■...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 distributed supply device. 40...Air box, 43...Fuel supply pipe, 47...Spreader. Patent applicant: Ube Industries, Ltd. Figure Z

Claims (1)

[Claims] In the spreader installed in the primary combustion space of the side wall of the fluidized bed, a blade having an arcuate side surface and an uneven front end is attached to the outer periphery of the rotor of the spreader. A fuel dispersion supply device for a fluidized bed boiler, characterized in that a plurality of fuel distribution units are provided at a predetermined pitch in the circumferential direction of the boiler.