JPS63169410A - Fluidized bed boiler - Google Patents

Abstract

PURPOSE:To provide an optimum desulfurizing condition, by a method wherein a drive device, changing the height of the opening of an inflow port, is mounted to a desulfurizing agent discharge cylinder having an inflow port opened to the upper layer of a desulfurizing agent. CONSTITUTION:An extraction cylinder 29, serving as a discharge cylinder, which is slidably engaged and inclined concentrically with an outer cylinder 27, is supported to a bearing 28 which is secured on the outer surface of a water-cooled wall 2, through a packing 30 so that it is movable forward and backward in a diagonally upper and lower direction. When an amount of sulfur in coal, SO2 concentration in waste gas, and the load of boiler are changed, they are detected by means of detectors 41, 42, and 43, respectively, to send a signal. A solenoid 35 is actuated through a computer 40 and a regulator 39, a piston rod 33 of an air cylinder 32 and the extraction cylinder 29 are integrally moved backward and forward to change the level of an inflow port 29a. In this case, the more a sulfur content in coal is increased, the more the height of the inflow port 29a is increased. Further, the more SO2 concentration in exhaust gas and a boiler load are increased, the height of the inflow port is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves supplying coal into a fluidized combustion chamber in which sand flows and combusting it, heating water in a heat transfer tube to generate steam, and after combustion. This relates to a fluidized bed boiler that desulfurizes the gas using a desulfurizing agent and discharges it to the outside.

[Conventional technology]

In recent years, fluidized bed boilers have been developed as boilers with high combustion efficiency and low waste gas pollution. This type of fluidized bed boiler has storage chambers separated from the bottom in order from the bottom of the boiler body.
It is equipped with three chambers, a combustion chamber and a desulfurization chamber, and the sand that is sent from the storage chamber to the combustion chamber and always stored in the combustion chamber in a predetermined amount is made to flow by blowing air, and the coal supplied to the combustion chamber is It burns while flowing with sand, and steam is generated by heating the water passing through the heat transfer tubes of the combustion chamber with the combustion gas. Then, the combustion gas is desulfurized with a desulfurizing agent such as limestone in the desulfurization chamber and exhausted, and unburned carbon is captured and burned in the desulfurization chamber.

[Problem that the invention seeks to solve]

However, in conventional fluidized bed boilers, the layer height of the desulfurization agent in the desulfurization chamber remains the same regardless of whether the 802 concentration in the combustion gas is large or small, which varies depending on the sulfur content in the supplied coal. (If coal with a high sulfur content is used, the amount of SO2 in the waste gas may exceed the emission regulation amount), and because the blower power is always secured to match the maximum sulfur content, there is no power available. Not only is this wasteful, but there is also the problem that optimal desulfurization conditions cannot be obtained when considering the pressure balance during operation. moreover,
If this boiler is operated under normal load and the load decreases, the amount of combustion gas decreases and the fluidization height also decreases, but in this case, the height at which the desulfurizing agent is extracted remains constant and does not decrease.
When the amount of desulfurization agent retained in the desulfurization bed is large, the pressure loss in the desulfurization bed increases despite the low load, and the operating cost increases due to the increase in blower power. In addition, even if the load suddenly increases and the fluidization height increases due to a large amount of combustion gas, if the height at which the desulfurizing agent is extracted remains constant and does not rise, a large amount of waste limestone will be discharged at once and the exhaust system will There was a problem that the capacity of the machine was exceeded and accidents such as clogging occurred, making processing troublesome.

[Means for Solving the Problems] In order to solve these problems, the present invention provides a desulfurizing agent discharge cylinder having an inlet opening to the upper layer of the desulfurizing agent, and has a height of the opening of the inlet. Equipped with a drive device that changes the
A desulfurization agent layer height control device was provided to operate a drive device by detecting at least one of the boiler load, the Sox concentration in the exhaust gas, and the sulfur content in the coal.

[Effect]

When the sulfur content of the coal, the SO2 concentration in the waste gas, and the boiler load increase or decrease during boiler operation, the control device detects this and operates the drive device to change the height of the inlet opening of the desulfurization agent discharge cylinder. The layer height of the desulfurizing agent will correspond to each of the above conditions.

〔Example〕

FIG. 1 is a longitudinal sectional view showing an embodiment of a fluidized bed boiler according to the present invention. In the figure, the main body 1 of the fluidized bed boiler is formed into a rectangular box shape surrounded on four sides by water cooling walls 2 in which a plurality of water cooling pipes (not shown) are buried, and inside thereof,
Three stages of water-cooled pipes and three-person partition plates 4, 5.6 separate air chamber 7° and storage room 8. Combustion chamber9. A desulfurization chamber 10 is separated. Blow pipes 11 and 12 connected to a blower device (not shown) are respectively inserted into the air chamber 7 and the storage chamber 8, and air is blown into the combustion chamber 9.
A pneumatic coal supply pipe 13 connected to a coal supply hopper (not shown) via a dryer and a crusher is inserted to supply coal. Furthermore, a pneumatic limestone transport pipe 14 connected to a limestone supply hopper (not shown) via a crusher is inserted into the desulfurization chamber 10, so that a predetermined amount of desulfurization agent is always kept in the desulfurization chamber 10. Limestone 15 is supplied in such a way that it can be stored. Reference numeral 16 denotes a heat transfer tube installed in a curved manner so as to reciprocate in a staggered manner within the combustion chamber 9, and an air supply tube 1T connected to one end thereof is connected to a circulation pump, and is connected to the other end. The supply pipe 1B is connected to steam using equipment. In this embodiment, a bypass is provided that connects the air supply pipe 17 and the supply pipe 18 midway, and serves as a heat transfer pipe for a separately provided exhaust heat utilization boiler. A plurality of distributors 19 are provided on each of the partition plates 4, 5, 6, and distribute the blown air uniformly and blow it upward into the chambers.

Sand 20 as a fluid medium having a diameter of about 1.6W is stored in the storage chamber 8, and the same sand 20 is also stored in the combustion chamber 9 under the coal to be supplied. is stored in Reference numerals 21 and 22 indicate an upper comer and a downcomer for the sand 20, which are provided in communication with the storage chamber 8 and the combustion chamber 9, and the sand 20 is transferred between the two chambers 8 and 9 manually or by level detection using a sensor. The structure is such that the amount of sand 20 in the combustion chamber 9 is kept constant at all times. On the other hand, an exhaust port 23 for discharging combustion gas is provided at the upper end of the desulfurization chamber 10 and is connected to the chimney via the exhaust heat utilization boiler via a duct.

Further, the desulfurization chamber 10 is provided with a desulfurization agent extraction device 24 equipped with a desulfurization agent layer height control device. That is, an outer cylinder 2T connected to a waste limestone storage tank (not shown) through a pipe body 26 is fixed to a bracket 25 fixed to the outer surface of the water-cooled wall 2 in an inclined manner. A bearing 28 fixed to the outer surface of the water-cooled wall 2 is slidably fitted into the outer cylinder 27, and an extraction cylinder 29 serving as a discharge cylinder tilts concentrically with the outer cylinder 27. It is supported freely to advance and retreat. Reference numeral 31 denotes a packing holder that prevents the packing 30 from coming off. The extraction tube 29 penetrates the water-cooled wall 2 and is inserted into the layer of limestone 15, and the waste limestone 15 that has been altered due to desulfurization and collected in the upper layer overflows into the extraction tube 29 and is removed from the outer tube. 27 and the pipe body 26 to be discharged to a waste limestone storage tank or the like. As a result, the inlet 29a of the extraction tube 29 is always open to the upper end surface of the limestone 15. Reference numeral 32 denotes an air cylinder as an easy-to-extract drive device that is supported by the merracket 25 in parallel with the outer cylinder 2T.
In addition, the head end side port and the rond end side boat are connected between the solenoid valve 35 and the piping 36.3.
7 are connected to each other. On the other hand, the control device 38
A controller 39 connected to the solenoid valve 35 and this controller 39
The computing unit 40 includes a detector 41 that detects the sulfur content of the coal supplied to the boiler and issues a signal, and a detector 41 that detects the sulfur content of the coal supplied to the boiler and issues a signal, and A detector 42 that detects the Sow concentration in the gas and issues a signal at °C, and a detector 43 that detects the load of the boiler and issues a signal are connected to each other. By doing this, when the amount of sulfur in the coal, the SO2 concentration in the waste gas, and the load on the boiler change, the detectors 41, 42, and 43 detect this and issue a signal, which causes the computer 40 and the controller to 39
The solenoid valve 35 is actuated via the air cylinder 32, and the piston rod 33 of the air cylinder 32 and the extraction cylinder 29 move forward and backward together, thereby changing the height of the inlet 29a. In this case, the height of the inlet 29a increases as the sulfur content in the coal increases, and the height of the inlet 29a increases as the 802 concentration of the waste gas increases. In addition, the larger the boiler load, the higher it becomes.

The operation of the fluidized bed boiler configured as above will be explained. After supplying coal to the upper layer of sand 21 stored in the combustion chamber 9 and sending air to the air chamber T, storage W, and chamber 8, the coal preheated with a burner etc. is ignited, and air for combustion is supplied. Coal burns at 100°C, and this combustion is carried out by distributor 1
The sand 21 and the coal are fluidized by the air blown up from the combustion chamber 9, thereby promoting efficient combustion. This combustion heats the water in the heat transfer tubes 16 to generate steam, which is supplied to steam-using equipment. On the other hand, the combustion gas passes through the distributor 19, enters the desulfurization N10, removes the sulfur content, becomes a harmless gas, and is discharged from the exhaust port 23.
Unburnt carbon is captured and burned within the desulfurized N10.

When the combustion gas discharged from the exhaust port 23 passes through a separately provided boiler 7, it heats up the steam headed from the supply pipe 18 to the steam usage equipment, and then is discharged from the chimney.

In addition, among the limestone 15 in the desulfurization chamber 10, the limestone 15 that has changed in quality due to desulfurization and has gathered in an upper layer such that the height of the inlet 29a is also increased, overflows from the inlet 29a, and the limestone 15 that has deteriorated due to desulfurization and has accumulated in the upper layer so that the height of the inlet 29a becomes higher, overflows from the inlet 29a and the outer tube 27. , pipe body 26, and is discharged to a waste limestone storage tank or the like.

In a fluidized bed boiler that operates in this manner, if the coal supplied from the coal supply pipe 13 changes to, for example, coal with a high sulfur content, and the height of the inlet port 29m of the extraction tube is low, combustion gas and limestone 15 will mix. If the contact time of 802 is too short, the concentration of 802 in the waste gas discharged from the exhaust port 23 becomes high and tends to exceed the regulation value. However, in this device, when the sulfur content in the coal increases, the detector 4
1 detects this and moves the piston rod 33t of the air cylinder 32 forward through the calculator 40 and controller 39, so that the inlet 29& becomes higher as shown by the chain line 29b in FIG. decreases and the height of the layer increases. Therefore, the contact time between the combustion gas and the limestone 15 is longer, and the Soz concentration in the waste gas is lowered. As a result of the experiment, when changing from normal coal to high sulfur coal, the SO2 concentration of the waste gas will decrease to 11 if the inlet port 29a remains unchanged.
By increasing the height of the inlet port 29a as described above, even in the case of high sulfur coal, it was possible to reduce the content from 00 ppm to 320 ppm, which is the same as 1100 ppm with normal coal. Furthermore, if the sulfur content of the coal is low and the height of the limestone layer is too high, more power will be consumed than necessary for desulfurization.
Although the pressure loss also becomes large, this device uses the control device as shown in FIG. pressure loss. In this device, by providing the detector 42, the layer height of the limestone 15 can be controlled by detecting the concentration of SO in the waste gas, so that it has the same effect as described above.

Furthermore, when the boiler load is low during normal operation, the amount of combustion gas is small and the bed height of the limestone 15 is too high, resulting in the same wasteful power consumption and pressure loss as described above. By providing this, it detects the load on the boiler 2 and lowers the inlet port 29a, thereby reducing power consumption and pressure loss. In addition, if the load on the boiler suddenly increases during normal operation, the height of the desulfurization bed will increase rapidly, but in this device the detector 43a detects the load and operates the air cylinder 32, Since the height of the limestone 29 is made high, a large amount of limestone 15 is not discharged suddenly, and the discharge system is not clogged with waste limestone.

Figures 2) and 2(b) show a desulfurizing agent discharge cylinder and its driving device as another embodiment of the present invention, and Figure 2(a)
Figure 2) is a front view, and Figure 2) is a longitudinal sectional view.

In these figures, on the inner surface of the water cooling wall 2 having the heat insulating material 2&, there is a guide ring 50 having a U-shaped cross section and a half ring shape.
The guide ring 50 is fixed with screws or the like facing the desulfurization chamber 10, and has an adjustment plate 5 formed in a circular plate shape.
1 is rotatably supported. A duct 52 is installed on the outer surface of the water-cooled wall 2 to connect it to a waste limestone storage tank (not shown).
An inclined cylindrical hollow member 55 passing through the water cooling wall 2 is connected between the outflow port 53 and an inflow port 54 provided on the outer periphery of the adjustment plate 51. communicated by. That is, the inlet 54, the hollow member 55, and the outlet 53 form a limestone discharge pipe 56 as a desulfurizing agent discharge cylinder that discharges the limestone 15 to the outside of the main body 1. 5T is a ground metal fixed to the outer surface of the water-cooled wall 2 corresponding to the center of the adjustment plate 51, and in its inner hole is a nine-packet 59 which is held down by a packing holder 58.
is loaded, and the packing 59 has an adjusting plate 5 at its tip.
A drive shaft 60 fixed to 1 is rotatably supported. A motor shaft 62 of a motor 61 supported on the main body side via a bracket (not shown) is connected to the drive shaft 60 through a coupling 6.
It is connected by 3.

Further, the motor 61 is connected to the same control device as in FIG. 1, which is not shown. By doing so, when the motor 61 rotates in response to a command from the control device as described above,
As the adjusting plate 51 rotates, the height of the inlet 54 at the eccentric position changes, so the height at which the limestone 15 is extracted changes.

FIG. 3 is a longitudinal cross-sectional view of a desulfurizing agent discharge cylinder and its driving device showing another embodiment of the present invention corresponding to FIG. 2(b). A ground metal TO is fixed to the wall 2 corresponding to the outside of the desulfurization chamber 10, and a limestone discharge pipe 71 formed in a dogleg shape as a desulfurization agent discharge cylinder is folded to this ground metal 70. The inflow lower 1a, which is a curved end, is rotatably supported facing the upper end surface of the limestone 15, and the outflow lower 1b is rotatably connected to a duct connected to a waste limestone storage tank, etc. It is joined. 72 is limestone discharge pipe 71 and gear 73.74
This is a motor that is driven and connected to the main body and supported on the main body side. The same control device as in FIG. 1, which is not shown, is connected to the motor T2. By doing this, when the motor T2 rotates in response to a command from the control device as described above, the limestone discharge pipe 71 rotates and its inflow lower 1m swings as shown by the solid line and chain line in the figure. , the height of the opening changes,
The extraction height of limestone 15 changes.

FIG. 4 is a longitudinal cross-sectional view of a desulfurizing agent discharge cylinder and its driving device showing another embodiment of the present invention corresponding to FIG. 2(b). A limestone discharge pipe 81 as a desulfurizing agent discharge cylinder bent in an N-shape is rotatably supported on the water-cooled wall 2 and a hollow bearing 80 fixed thereto. A motor 82 supported on the main body 1 side is drivingly connected to the protruding end via a coupling 83.

Further, the bearing 80 is provided with an outlet 84 connected to the waste limestone storage tank through a duct, and the engagement portion of the limestone discharge pipe 81 with the bearing 80 is provided with a plurality of holes 81a.
, 81b are drilled. The same control device as in FIG. 1, not shown, is connected to the motor 82. By doing this, when the motor 82 rotates in response to a command from the control device as described above, the limestone discharge pipe 81 rotates, the height of its inlet port 81c changes, and the height at which the limestone 15 is extracted changes. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a fluidized bed boiler, a desulfurizing agent discharge cylinder is provided with an inlet opening to the upper layer of the desulfurizing agent, and the opening height of the inlet is varied. A desulfurization agent layer height control device is installed to operate the drive device by detecting at least one of the boiler load, the Son concentration in the exhaust gas, and the sulfur content in the coal. sulfur content in coal and S in waste gas.
h When the concentration and boiler load increase or decrease, the control device detects this and operates the drive device to change the height of the inlet opening of the desulfurizing agent discharge cylinder to adjust the layer height of the desulfurizing agent to each of the above conditions. As the sulfur content in the coal increases, the desulfurization bed becomes high, the SO2 concentration in the waste gas becomes low and does not exceed the regulation amount, and the sulfur content in the coal is low, so the waste gas When the So2 concentration in the reactor becomes lower or the boiler load becomes lower, the desulfurization bed becomes lower, eliminating power consumption for desulfurization and reducing pressure loss, reducing operating costs. be done.

In addition, when the load on Boi 2 increases, the desulfurization bed is not high enough to prevent waste limestone from being discharged in large quantities.
It is possible to avoid clogging of the discharge system, eliminate processing time, and improve operational efficiency.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the fluidized bed boiler according to the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 (&),
(b) shows a desulfurizing agent discharge cylinder and its driving device as another embodiment of the present invention, and FIG. 2 is a front view thereof, and FIG. FIG. 4 is a longitudinal sectional view of a desulfurizing agent discharge cylinder and its driving device showing other embodiments of the present invention. 1... Main body, 2... Water cooling wall, 10... Desulfurization chamber, 13... Coal discharge pipe, 14... Limestone transport pipe, 15... Limestone, 23...・-・Discharge port, 24
...ψ desulfurization side extraction device, 27... superior outer cylinder, 29
...Extraction tube, 32Φ...Air cylinder, 33
... Piston Rondo, 35 ... Solenoid valve, 38.
...Control device, 39.. Controller, 40.. Arithmetic unit, 41.42.43-.O.Detector, 50..
Guide ring, 51... Φ0 adjustment plate, 53... Outlet, 54... Inlet, 55... Hollow member, 56
, 71.81... limestone discharge pipe, 61°72...
- Motor, 71a, 81e...Inlet.

Claims (1)

[Claims] A desulfurizing agent discharge cylinder having an inlet opening to the upper layer of desulfurizing agent inside the main body is provided, and a drive device for changing the opening height of the inlet is attached to this discharge cylinder, and the load of the boiler is SO_ in the waste gas discharged from this boiler
1. A fluidized bed boiler, comprising: a desulfurizing agent bed height control device that detects at least one of the following: sulfur concentration and sulfur content in coal supplied to the boiler to operate the drive device.