JP3131486B2 - How to protect high-temperature and high-pressure dust removal equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature and high-pressure dedusting device for removing minute ash in high-temperature and high-pressure combustion gas, which is attached to a coal-fired pressurized fluidized-bed boiler combined cycle system.
In particular, the present invention relates to a method for protecting a high-temperature and high-pressure dust remover, which prevents damage to the high-temperature and high-pressure dust remover due to reburning of unburned components generated in the device.

[0002]

2. Description of the Related Art Conventionally, a coal-fired pressurized fluidized-bed boiler combined cycle power generation system has a high-temperature and high-pressure dedusting device together with a cyclone for removing ash dust from high-temperature and high-pressure combustion gas generated in a coal-fired pressurized fluidized-bed boiler. It is attached. This high-temperature and high-pressure dust removal device is a precision dust removal device that further removes fine dust in the combustion gas that has not been removed by the cyclone.
Generally, a heat-resistant multi-tube multi-chamber structure is used.

As shown in FIG. 2, the multi-tube, multi-chamber high-temperature, high-pressure dust removing apparatus has a plurality of tubular ceramic filters between upper and lower tube plates b, c provided in a vertically hollow body a. g
Is provided, a combustion gas inlet d is formed at an upper end of the vertical body a, and a dust outlet e is formed at a lower end.
A plurality of clean gas outlet pipes f are connected to a vertical body a located between the upper and lower pipe plates b and c, and gas is discharged to the distal ends of these clean gas outlet pipes f so as to connect them. A pipe h is erected, and a backwash gas pipe i for injecting a high-speed backwash gas into the clean gas outlet pipe f is provided at each connection port of the gas discharge pipe f. It has a configuration provided.

[0004] As shown by the arrow in the figure, a high-temperature and high-pressure combustion gas G containing dust D introduced into the vertical body a from the combustion gas inlet d flows to the tubular ceramic filter g side, and the lower tube sheet is formed. While reaching the c-side, the dust D is filtered through the tubular ceramic filter g to become a clean gas S, passes through each clean gas outlet pipe f, and is joined and exhausted by the gas discharge pipe h. ing. Then, the high-pressure gas for backwashing is injected into the respective clean gas outlet pipes f from the backwash gas pipe i at intervals of 10 to 15 minutes to generate high-pressure pressure waves utilizing the ejector effect. With this pressure wave, the dust layer adhered and deposited on the inner wall surface of the tubular ceramic filter g is forcibly peeled off and removed.

Thereafter, the dust removed from the inner wall surface of the tubular high-temperature high-pressure filter g by the backwashing high-speed gas K from the backwash gas pipe i as described above is removed by its own weight.
It falls to the inner lower part, and is appropriately discharged from the vertical body a via the lock hopper h provided at the dust discharge port e.

[0006]

The oxygen concentration in the combustion gas G introduced into the high-temperature and high-pressure dedusting apparatus is 3 to 5% during normal operation, but the load on the boiler increases. In this case, low air operation is performed, and the oxygen concentration in the combustion gas G decreases to 1.5 to 3% or less, so that unburned components in the dust D scattered in the combustion gas G are temporarily reduced. To accumulate on the inner wall of the tubular ceramic filter g. When the load of the boiler fluctuates in such a state, and the oxygen concentration in the combustion gas G increases, dust D containing a large amount of unburned matter deposited and deposited inside the tubular ceramic filter g is removed. The inner surface re-combustes spontaneously and abnormally raises the temperature of the inner surface of the tubular ceramic filter g, causing a large temperature difference between the inner surface and the outer surface. There was something. In particular, the cracks often occurred in the lower part of the tubular ceramic filter g where the flow rate of the combustion gas G was reduced and the stagnation was likely to occur.

For this reason, it is conceivable to reduce the amount of dust D containing unburned components by shortening the interval of jetting the backwashing high-speed gas in advance, but in view of the operating efficiency during normal operation, Since the interval of jetting the backwashing high-speed gas is optimally 10 to 15 minutes, if it is unnecessarily shortened, the problem arises that the filtration efficiency of the high-temperature and high-pressure dust remover is reduced.

Accordingly, the present invention has been devised to effectively solve these problems, and an object of the present invention is to provide a tubular ceramic filter by reburning unburned components in dust accumulated on the inner wall of the tubular ceramic filter. An object of the present invention is to provide a method for protecting a high-temperature and high-pressure dust removing device in which cracks generated in a filter are prevented beforehand.

[0009]

In order to achieve the above object, the present invention provides a filter chamber by providing a plurality of tubular ceramic filters between upper and lower tube plates in a vertical body, and further comprises an upper end of the vertical body. In addition, the combustion gas inlet for introducing the combustion gas,
A dust discharge port is formed at the lower end, and further, a clean gas outlet pipe and a high pressure gas for backwashing are injected at predetermined intervals into the vertical body of the filtration chamber and adhere to the inner wall of the tubular ceramic filter. In a high-temperature and high-pressure dedusting device connected to a backwash gas pipe for removing the generated dust, an oxygen concentration detection sensor for detecting an oxygen concentration in the introduced combustion gas and a temperature of the combustion gas are detected at the combustion gas inlet. A combustion gas temperature sensor is provided, and a clean gas temperature sensor for detecting a temperature of the clean gas to be exhausted is provided at the clean gas outlet pipe, so that an oxygen concentration in the combustion gas introduced from the combustion gas inlet becomes equal to or lower than a predetermined concentration. When the temperature of the clean gas exhausted from the clean gas outlet pipe is lowered, or when the temperature of the clean gas exhausted from the combustion gas inlet is higher than the temperature of the combustion gas introduced from the combustion gas inlet pipe, the gas is injected from the backwash gas pipe. The injection interval of the high-pressure gas backwash to,
This is shorter than the predetermined interval.

[0010]

According to the present invention, as described above, an oxygen concentration detection sensor for detecting the oxygen concentration in the combustion gas is provided at the combustion gas inlet, and the oxygen concentration in the combustion gas introduced from the combustion gas inlet is equal to or less than a predetermined concentration. In this case, the injection interval of the backwashing high-pressure gas ejected from the backwashing gas pipe is shorter than a predetermined interval, so that dust containing a large amount of unburned matter on the inner wall surface of the tubular ceramic filter. The amount of adhesion will be greatly reduced. Therefore, even if unburned components in the dust adhering to the inner wall surface of the tubular ceramic filter are re-burned, the burning time is greatly reduced as compared with the conventional case, thereby preventing damage to the tubular ceramic filter due to thermal stress. can do. Further, a combustion gas temperature sensor for detecting the temperature of the combustion gas is provided at the combustion gas inlet, and a clean gas temperature sensor for detecting the clean gas temperature is provided at the clean gas outlet pipe, and the exhaust gas is exhausted from the clean gas outlet pipe. When the clean gas temperature is higher than the temperature of the combustion gas introduced from the combustion gas inlet, the injection interval of the backwash high-pressure gas ejected from the backwash gas pipe is shorter than the predetermined interval. Even if re-combustion occurs on the inner wall surface of the tubular ceramic filter, the burning time is shortened, and damage to the tubular ceramic filter due to thermal stress can be prevented as before.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a multi-tube, multi-chamber high-temperature and high-pressure dust removing apparatus according to the present invention. As shown in the figure, in this multi-tube, multi-chamber high-temperature, high-pressure dust removing apparatus, upper and lower tube plates 2 and 3 are provided in a vertically hollow body 1 formed of a heat-resistant material such as a steel plate. , The upper and lower tube sheets 2,
Between the three, there are provided two tubular ceramic filters 4 connected to penetrate these. Further, between these upper and lower tube sheets 2 and 3, a tubular ceramic filter 4 is provided.
Are formed in the middle part of the filter plate to further stably support the tubular ceramic filter 4 and partition the upper and lower tube sheets 2 and 3 into three sections. That is, the interior of the vertical body 1 is firstly divided into an upper chamber 6, a filtration chamber 7, and a lower chamber 8 from above by the space between the upper and lower tube sheets 2 and 3, and further filtered by the two intermediate tube sheets 5a and 5b. The first filtration chamber 7a, the second filtration chamber 7b,
It is partitioned into three of the third filtration chamber 7c.

The tubular ceramic filter 4 is made of, for example, S
It is formed by sintering ceramic fine powder such as iO ₂ to form a tube with an open top and bottom, and has a large number of holes of about several μm. The combustion gas G is cleaned by collecting minute dust D of several μm to several tens μm in the high-pressure combustion gas G.

The upper end of the vertical body 1 is roughly dust-freed with a cyclone (not shown) at 600 to 800 ° C.
A combustion gas inlet 9 for introducing combustion gas G of a certain degree is formed, and a dust discharge port 10 provided with a lock hopper 15 for discharging dust D in the combustion gas G is formed at the lower end thereof. Have been. Furthermore, this vertical body 1
Of the filtration chamber 7, the first filtration chamber 7a, the second filtration chamber 7b, and the third filtration chamber 7c are provided with three cleaning gases for discharging the cleaning gas S from which the dust D has been removed. Outlet pipe 1
1a, 11b, and 11c are horizontally formed in parallel.

Each of these clean gas outlet pipes 11a, 1
Gas exhaust pipes 12 are provided upright at the ends of 1b and 11c so as to connect them, and the clean gas S flowing from each of the clean gas outlet pipes 11a, 11b and 11c is merged and exhausted. ing. In addition, each of the connection ports 13a, 13b, 13c between the gas discharge pipe 12 and each of the clean gas outlet pipes 11a, 11b, 11c is provided with a backwash gas pipe 14a, 14b, 14c opposed thereto. Yes,
A high-speed backwash gas is injected into each of the clean gas outlet pipes 11a, 11b, 11c. The backwash gas pipes 14a, 14b, and 14c are connected to a high-pressure air tank 16, and the high-pressure air tank 16 is separated by a high-pressure air tank control device 19 described below at intervals of 3 to 15 minutes.
The high-pressure gas is sent to the backwash gas pipes 14a, 14b, 14c.

An oxygen concentration detecting sensor 16 is provided at the combustion gas inlet 9 to detect the oxygen concentration in the combustion gas G introduced into the vertical body 1 from a boiler (not shown). , And the detected value is input to the high-pressure air tank control device 19. Further, a combustion gas temperature sensor 17 is provided at the combustion gas inlet 9 together with an oxygen concentration detection sensor 16 to detect the inlet temperature of the combustion gas G and input the detected value to a temperature difference detector 18. I have. Further, the gas discharge pipe 12 is provided with a clean gas temperature sensor 21 for detecting the temperature of the clean gas S exhausted from the gas, and
The detected value is input to the temperature difference detector 18 in the same manner as the combustion gas temperature sensor 17. The temperature difference detector 18 is connected to the high-pressure air tank control device 19, monitors the temperature input from the combustion gas temperature sensor 17 and the clean gas temperature sensor 21, and detects the temperature input from the clean gas temperature sensor 21. When the temperature exceeds the temperature input from the gas temperature sensor 17, the signal is sent to the high-pressure air tank controller 1.
9 is input. The high-pressure air tank controller 19 controls the supply interval of the backwashing high-speed gas to the high-pressure air tank 16, particularly the backwash gas pipes 14a, 14b, and 14c. When the oxygen concentration in the combustion gas G falls below 3%, or when a signal from the temperature difference detector 18 is input, the supply interval of the high-speed backwash gas is set to, for example, 3
It is designed to be reduced to minute intervals.

Next, the operation of this embodiment will be described.

As shown in FIG. 1, first, a combustion gas G roughly dusted by a cyclone (not shown) is introduced into an upper space 6 from a combustion gas inlet 9 at an upper end of a vertical body 1 and a pipe. It flows from the upper end of the mold filter 4 to the filtration space 7 side. Then, first, after a portion of the combustion gas G is transmitted through the upper wall of the tubular ceramic filter 4 and the dust D contained when flowing to the first filtration chamber 7a side is removed, the combustion gas G is converted into a clean gas S. The gas flows through the clean gas outlet pipe 11 a into the gas discharge pipe 12. Next, a part of the combustion gas G flowing further downward in the tubular ceramic filter 4 is subjected to removal of dust D contained when flowing from the middle stage of the tubular ceramic filter 4 to the second filtration chamber 7b in the same manner as described above. After being converted into the clean gas S, the gas passes through the clean gas outlet pipe 11b and passes through the gas discharge pipe 1
Flow into 2. Then, the flow rate of the remaining combustion gas G that has finally flowed to the lower portion of the tubular ceramic filter 4 is rapidly reduced here, and substantially stays on the inner surface of the lower portion of the tubular ceramic filter 4, and the third filtration is slowly performed. When flowing to the chamber 7c side, the dust D contained therein is removed and turned into clean gas S, and then flows into the gas discharge pipe 12 through the clean gas outlet pipe 11c.

Next, when the above-described filtration state of the combustion gas G continues for a predetermined time and the dust D in the combustion gas G adheres and accumulates on the inner wall surface of the tubular ceramic filter 4, a dust layer is formed. Since the filtration efficiency is reduced, a high-speed backwashing high-speed gas is supplied from the high-pressure air tank 20 to each of the backwash gas pipes 14a, 14b, and 14c, and the backwash gas pipes 14a, 14a.
4b, 14c to each clean gas outlet pipe 11a, 1
A high-speed backwashing high-speed gas is injected to 1b and 11c to remove the dust layer so as to blow it off. That is,
The backwashing high-speed gas entrains the air in the gas exhaust pipe 12 by the ejector effect, and generates high-pressure waves in the first filtration chamber 7a, the second filtration chamber 7b, and the third filtration chamber 7c of the filtration chamber 7, respectively. Let it. Then, the dust layer adhered and deposited on the inner wall surface of the tubular ceramic filter 4 is peeled off and blown off by the high pressure wave, and then falls down in the tubular ceramic filter 4 by its own weight, and the lock hopper 15
Is discharged out of the vertical body 1 from the dust discharge port 10 provided with Normally, the supply of the high-speed backwash gas from the high-pressure air tank 20 to the backwash gas pipes 14a, 14b, 14c is performed at intervals of 10 to 15 minutes. At this time, the oxygen concentration in the combustion gas G is 3 to 5%.

However, the load of a boiler (not shown) attached to the upstream side of the high-temperature and high-pressure dust removing device is increased, the operation becomes low air, and the oxygen concentration in the combustion gas G becomes 1.5 to 3 times. %, It is reduced to the combustion gas inlet 9
The oxygen concentration detection sensor 16 provided in the
Input to the high-pressure air tank controller 19. Then, the high-pressure air tank controller 20 determines that the unburned portion in the dust D scattered in the combustion gas G has increased, and the high-pressure air tank 20 sends the backwash gas pipes 14a, 14
b, 14c, the supply interval of the high-speed gas for backwashing is set to 10 to 15
The shortening control is performed so that the supply is performed at intervals of three minutes from minutes.

Thus, the tubular ceramic filter 4
Since the dust D having a large content of unburned content on the inner wall is frequently removed and the amount of the accumulated dust D is reduced, the dust D having a large content of the unburned content is reburned in the tubular ceramic filter 4. Even in this case, the combustion time can be shortened, and excessive thermal stress on the tubular ceramic filter 4 can be prevented. When the oxygen concentration in the combustion gas G becomes 3% or more, the oxygen concentration detection sensor 1
6, the high-pressure air tank controller 20 determines that the dust D containing a large amount of unburned gas in the combustion gas G is reduced, and the high-pressure air tank 20 returns the backwash gas pipes 14a, 14b, The supply interval of the backwash high-speed gas to 14c is controlled so as to be supplied at the original interval of 10 to 15 minutes.

On the other hand, the clean gas temperature and the combustion gas temperature are constantly detected by the clean gas temperature sensor 21 and the combustion gas temperature sensor 17, and the detected values are input to the temperature difference detector 18. During normal operation, the temperature of the clean gas is lower than the temperature of the combustion gas. However, if dust D adhering to the inner wall of the tubular ceramic filter 4 reburns, the temperature of the clean gas exceeds the temperature of the combustion gas, and the temperature difference is detected. The detector 18 detects the signal and inputs it to the high-pressure air tank controller 19. Then, the high-pressure air tank control device 19 determines that re-combustion has occurred inside the tubular ceramic filter 4, and similarly to the signal from the oxygen concentration detection sensor 16,
Backwash gas pipes 14a, 14b, 1 from high pressure air tank 20
The supply interval of the high-speed gas for backwashing to 4c is shortened and controlled so as to be supplied at intervals of 10 to 15 minutes to 3 minutes, thereby extinguishing reburning on the inner wall of the tubular ceramic filter 4.
That is, even if the detected value of the oxygen concentration by the oxygen concentration detection sensor 16 becomes 1.5 to 3% or less as described above, the dust D adhered to the inner wall of the tubular ceramic filter 4 reburns. Since the temperature of the clean gas S is higher than the temperature of the combustion gas G, detection of the temperature will shorten the reburning time and extinguish the fire. When the reburning on the inner wall of the tubular ceramic filter 4 stops, the temperature of the clean gas S falls below the temperature of the combustion gas G.
This is detected by the temperature difference detector 18 and input to the high-pressure air tank control device 19, whereby the high-pressure air tank control device 19 determines that there is no re-combustion inside the tubular ceramic filter 4, and Detection sensor 1
6, the supply interval of the high-speed backwash gas from the high-pressure air tank 20 to the backwash gas pipes 14a, 14b, 14c is controlled to return from the 3-minute interval to the 10-15-minute interval in the normal operation. Will be.

As described above, according to the present invention, when the reburning is likely to occur inside the tubular ceramic filter 4 or when the reburning occurs, the supply interval of the backwashing high-speed gas K is quickly reduced. Thus, the frequency of occurrence of reburning can be reduced, and even if reburning occurs, the burning time can be shortened. Therefore, it is possible to prevent the tubular ceramic filter 4 from being damaged due to excessive thermal stress due to unburned portion reburning, and it is possible to prevent the filtration efficiency of the apparatus from being unnecessarily reduced.

[0024]

In summary, according to the present invention, it is possible to prevent cracks which have conventionally occurred in a tubular ceramic filter, and to greatly improve the durability and reliability of the device. Has an effect.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing an embodiment of a high-temperature and high-pressure dust removing apparatus according to the present invention.

FIG. 2 is an overall schematic view showing one embodiment of a conventional high-temperature and high-pressure dust removing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical body 2 Upper tube sheet 3 Lower tube sheet 4 Tube ceramic filter 7 Filtration chamber 9 Combustion gas inlet 10 Dust outlet 11 Clean gas outlet 16 Oxygen concentration detection sensor 17 Combustion gas temperature sensor 21 Clean gas temperature sensor D Dust G Combustion gas K High-speed gas for backwashing S Clean gas

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sadayuki Komatsuzaki 3-2-1, Toyosu, Koto-ku, Tokyo Ishikawa Shima-Harima Heavy Industries, Ltd. 268331 (JP, A) Japanese Utility Model Showa 61-175522 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 46/00-46/54

Claims (1)

(57) [Claims] 1. A filter chamber is formed by providing a plurality of tubular ceramic filters between upper and lower tube plates in a vertical body, and a combustion gas inlet for introducing a combustion gas is provided at an upper end of the vertical body, and at a lower end thereof. A dust discharge port is formed, and further, a clean gas outlet pipe is respectively provided to the vertical body of the filtration chamber, and a high pressure gas for backwashing is injected into the filtration chamber at a predetermined interval, and dust adhered to the inner wall of the tubular ceramic filter. In the high-temperature and high-pressure dedusting device connected to a backwash gas pipe for removing gas, an oxygen concentration detection sensor for detecting an oxygen concentration in the introduced combustion gas and a combustion gas for detecting a temperature of the combustion gas are provided at the combustion gas inlet. While providing a temperature sensor, the clean gas outlet pipe,
A clean gas temperature sensor for detecting the temperature of the clean gas exhausted from the exhaust gas is provided, and when the oxygen concentration in the combustion gas introduced from the combustion gas inlet falls to a predetermined concentration or less, or when the exhaust gas is exhausted from the clean gas outlet pipe. The injection interval of the backwash high-pressure gas ejected from the backwash gas pipe when the clean gas temperature exceeds the temperature of the combustion gas introduced from the combustion gas inlet is shorter than the predetermined interval. Method of protecting high-temperature and high-pressure dust removal equipment.