JPH11253727A - Dust removing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control the back washing pressure of each filter block in a dust removing apparatus constituted of two or more filter blocks made of honeycomb type or cylindrical porous ceramic bodies installed in cylindrical cans arranged in the approximately vertical direction and having dust removing function. SOLUTION: This dust removing apparatus is constituted of two or more filter blocks 14, 15 made of porous ceramic pipes and installed in cylindrical cans 11. The filter blocks 14, 15 are back washed by back washing nozzles 25, 26 installed in a back washing air pipeline 29. Back washing valve front valves 33, 34 whose opening can be optionally set are installed in front of full opening and complete closing type back washing valves 27, 28 in the back washing air pipeline 29. The momentary back washing pressure values at the time of back washing are measured by differential pressure measuring apparatuses 35, 36 and a control apparatus for adjusting the opening of the back washing valve front valves 33, 34 as to keep the measured values within a proper range is installed in the dust removing apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-temperature dust-containing gas discharged from a combustion facility using fossil fuels such as coal,
The present invention relates to a dust remover used to remove various dust-containing gases such as dust-containing gases discharged from steelmaking, cement, chemical plants, and the like.

[0002]

2. Description of the Related Art In recent years, a dust removing apparatus using a cylindrical or honeycomb filter element made of a porous ceramic body for removing dust in a high-temperature gas has attracted attention. FIGS. 3 to 5 show a schematic configuration of a conventional dust remover mounted on one can of a pressurized fluidized bed boiler.

As shown in FIGS. 3 to 5, a cylindrical can body 11 constituting a dust removing device is disposed in a substantially vertical direction, and the inside is divided into an outer cylindrical portion and an inner cylindrical portion by a cylindrical partition wall 12. Have been. An outer cylinder filter block 14 and a plurality of inner cylinder filter blocks 15 each comprising a plurality of porous ceramic tubes 13 having a dust removing function are mounted on the outer cylinder part and the inner cylinder part of the can body 11, respectively. The upper and lower portions of the porous ceramic tube 13 of the blocks 14 and 15 are sealed and held by tube sheets 16 and 17 fixed to the can body 11, respectively.

[0004] An upper space 18 is formed in the upper part of the can body 11, and two dust-containing gas inlet pipes 19 are connected to each upper space 18 from one can of a pressurized fluidized bed boiler (not shown). Accordingly, the high-pressure and high-temperature dust-containing gas DG generated in one can of the pressurized fluidized-bed boiler is supplied to the two dust-containing gas inlet pipes 19.
Into the upper space 18 of the two dust removal devices,
The gas flows inside the ceramic tube 13 of the outer filter block 14 and the inner filter block 15 of each dust removing device, gas passes through the wall of the ceramic tube 13 from the inside to the outside, and the dust D passes through the ceramic tube 13. Filtration is performed by adhering to the inner wall of the.

On the other hand, a lower space 20 is formed in a lower portion of the can body 11, and a dust hopper 21 for storing dust D dropped from each of the filter blocks 14 and 15 is disposed in the lower space 20. An ash processing device (not shown) is connected to 21. Therefore, the dust D dropped from each of the filter blocks 14 and 15 is
The dust D accumulated in the dust hopper 21 is discharged out of the system by the ash treatment device.

[0006] The outer cylinder filter block 14 and the inner cylinder filter block 15 attached to the outer cylinder part and the inner cylinder part of the can body 11 are supplied with the filtered clean gas CG respectively.
An outer tube outlet tube 22 and an inner tube outlet tube 23 to be taken out of the apparatus are connected. The outer pipe 22 and the inner pipe 2
Numeral 3 is joined at its tip and connected to a clean gas outlet pipe 24. The two clean gas outlet pipes 24 are merged into one and then connected to a gas turbine generator (not shown), where the clean gas outlet pipe 24 is connected. Gas CG is supplied.

The outer tube outlet tube 22 and the inner tube outlet tube 23 are used for backwashing and removing the dust D adhering to the inner surface of each ceramic tube 13 after being removed by the outer tube filter block 14 and the inner tube filter block 15. Backwash nozzle 25,2
6 are respectively mounted. Each backwash nozzle 25, 26
Is the backwash air buffer tank 3 by the backwash air pipe 29.
2 in the vicinity of the connection between each backwash nozzle 25, 26 and the backwash air pipe 29.
7, 28 are arranged.

The backwash air buffer tank 32 and the backwash air compressor 30 are connected by a compressor outlet pipe 31, and the pressure inside the backwash air buffer tank 32 is controlled by the operating gas in the can 11 as shown in FIG. When the air pressure falls below the low pressure, the backwash air compressor 30 automatically starts up so that the pressure is maintained within a preset pressure range with respect to the pressure.
And if the air pressure exceeds the high pressure, backwash air compressor 3
0 is controlled to stop automatically, and the necessary backwash air is supplied to the backwash air buffer tank 32.

Backwashing is performed individually for each of the filter blocks 14 and 15. First, with respect to the first filter block, the backwash valve 27 or 28, which is normally fully closed, is set to 0.1.
After fully opening for 5 seconds to 1.0 second, the filter is completely closed immediately, and a high external pressure is applied to the outer surface of the porous ceramic tube 13 of the filter block 14 or 15 in a pulsed manner, so that the dust D adhering to the inner surface of the porous ceramic tube 13 is removed. Off.

[0010] Hereinafter, the same valve operation is sequentially performed at regular intervals for the other filter blocks to perform backwashing. When air is consumed by backwashing of a certain filter block and the inside pressure of the backwash air buffer tank 32 becomes lower than the set pressure range, the backwash air compressor 30 is automatically activated and the upper limit of the pressure range is set. Stops automatically when it reaches, and prepares for the next filter block backwash.

As described above, the high-pressure and high-temperature dust-containing gas DG generated in the pressurized fluidized-bed boiler is supplied to the dust-containing gas inlet pipe 19.
Accordingly, the gas is guided to the upper space 18 of the can body 11 and flows into the inside of each of the porous ceramic tubes 13 of the outer cylinder filter block 14 and the inner cylinder filter block 15, and the gas passes through the wall of the porous ceramic tube 13 from the inside. The dust D passes outward and is filtered by attaching to the inner wall of the porous ceramic tube 13.

The clean gas CG from which the dust has been removed flows into the clean gas outlet tube 24 from each of the filter blocks 14 and 15 through the outer tube outlet tube 22 and the inner tube outlet tube 23. Supplied to the turbine generator.

On the other hand, each of the porous ceramic tubes 1 of the outer cylinder filter block 14 and the inner cylinder filter block 15
The dust D adhering to the inner surface of the nozzle 3 is washed off by backwash air intermittently and sequentially jetted from the backwash nozzles 25 and 26 in a pulsed manner. Dust D accumulated in 21 is discharged out of the system by the ash treatment device.

[0014]

In a dust removing apparatus, if the backwash pressure is too high, filter components may be damaged, and if the backwash pressure is too low, the dust removing capability is reduced and the filter differential pressure is abnormal. And maintaining the backwash pressure of the dust removal device within the proper range prevents damage to the filter components, maintains the differential pressure appropriately, and ensures continuous operation of the plant. Although it is extremely important in performing the operation, the above-described conventional dust removing apparatus has a problem that the backwash pressure of each filter block cannot be properly controlled.

As described above, in the conventional dust remover, the internal pressure of the backwash air buffer tank 32 falls within a pressure range set in advance with respect to the operating gas pressure in the can body 11 as shown in FIG. The backwashing of each filter block 14 and 15 is automatically controlled so as to be maintained, and the backwashing is arranged in the backwashing air pipe 29 connecting the backwashing air buffer tank 32 and each filter block 14 and 15. Valve 27,
28 are intermittently and sequentially opened for 0.5 to 1.0 seconds and then fully closed immediately.

However, the backwash pressure varies greatly depending on the degree of contamination of the filter element during operation, gas temperature, boiler load, type of fuel (coal) used, ash properties, ash concentration, and the like. Differences in the degree of contamination of the elements, gas temperature, ash properties, ash concentration, etc. also occur between the filter blocks 14 and 15 during operation. The washing pressure changed one after another, and there were many cases where the washing was operated far outside the appropriate range of the backwash pressure.

In the conventional backwashing equipment and control method of the dust removing apparatus, the backwash pressure of each of the filter blocks 14 and 15 cannot be always controlled so as not to largely deviate from the range of an appropriate value. In some cases, the operation of the filter must be stopped due to damage to the filter components due to the above, or abnormal rise in the filter differential pressure due to abnormally low backwash pressure. Further, since there is no alarm device for the abnormally high and low backwash pressure, there is a problem that the operator does not notice until a trouble occurs and the countermeasures and measures are delayed.

The present invention solves such a problem, prevents the backwash pressure of each filter block from operating outside a proper value range, and prevents the backwash when an unexpected situation occurs. It is an object of the present invention to provide a dust remover having an automatic control device capable of issuing an alarm when the pressure is abnormally increased or abnormally decreased.

[0019]

In order to solve the above-mentioned problems, the present invention provides a honeycomb-type or cylindrical-type porous ceramic body having a dust-removing function mounted in a substantially cylindrically-shaped can body. In a dust removal apparatus composed of two or more filter blocks, a full-open / fully-closed back-wash valve is provided in each back-wash air piping line communicating from the back-wash air buffer tank to each filter block, and the back-wash valve is provided. A backwash valve front valve whose opening can be arbitrarily set is provided upstream.

A differential pressure measuring device for measuring an instantaneous backwash pressure at the time of backwashing for each filter block, and the above-mentioned operation so that the backwash pressure of each filter block does not greatly deviate from a proper value range during operation. A control device for automatically adjusting the opening of the backwash valve front valve is provided.

This control device controls the backwash air compressor to start and stop so that the internal pressure of the backwash air buffer tank is maintained within a predetermined pressure range with respect to the operating gas pressure. When the backwash pressure of each filter block measured by the differential pressure measuring device is higher than a preset backwash pressure range, the opening degree of the backwash valve front valve is reduced,
When the pressure is lower than the appropriate backwash pressure range, the opening of the backwash valve front valve is opened.

According to the dust removing apparatus of the present invention configured as described above, the degree of contamination of the filter element over time, the gas temperature, the boiler load, and the fuel (coal) used during operation.
Type, ash properties, ash concentration, etc.
The backwash pressure of each filter block changes one after another.

As described above, in the conventional dust removing device,
Although there was a risk of operation being greatly deviated from the appropriate backwash pressure range, the dust removal device of the present invention measures the backwash pressure of each filter block during operation during operation, and measures the measured backwash pressure. If the pressure is higher than the preset proper backwash pressure range, the opening of the backwash valve front valve is automatically reduced according to the calculation result of the control unit (computer), If it is low, the opening of the backwash valve front valve is automatically opened according to the calculation result of the computer.

Therefore, in the dust removing apparatus of the present invention, the backwash pressure of each filter block is automatically adjusted so as not to be largely out of the range of an appropriate value. It is possible to prevent problems such as damage to the filter components and a shutdown caused by an abnormally high filter differential pressure due to a decrease in dust removal capability when the backwash pressure is too low.

According to the present invention, there is also provided a dust removing apparatus having the above-mentioned construction, wherein the back pressure measured by the differential pressure measuring device at each back washing of each filter block exceeds a predetermined back washing pressure abnormal height. Provided is a dust removal device provided with a maintenance device that automatically issues an alarm when a pressure lower than a predetermined backwash pressure abnormally low is provided.

In the dust removing apparatus of the present invention thus configured, the backwash pressure exceeds a preset backwash pressure abnormally high or falls below the backwash pressure abnormally low due to an unexpected situation during operation or the like. In such a case, an alarm is automatically issued, so that the operator can immediately notice the abnormality and take an appropriate measure or action at an early stage, thereby preventing the occurrence of a major trouble.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a dust removing device according to the present invention will be specifically described based on one embodiment shown in FIG.
Note that members having the same functions as those described in the related art are denoted by the same reference numerals for simplification of description.

As shown in FIG. 1, a can 1 having a cylindrical shape
1 is arranged almost vertically, and the inside is a cylindrical partition wall 1
It is divided into an outer cylinder part and an inner cylinder part by 2. An outer cylinder filter block 14 and an inner cylinder filter block 15 each comprising a plurality of porous ceramic tubes 13 having a dust removing function are provided on the outer cylinder part and the inner cylinder part of the can body 11.
The upper and lower portions of the porous ceramic tube 13 of each of the filter blocks 14 and 15 are sealed and held by tube sheets 16 and 17 fixed to the can body 11, respectively.

An upper space 18 is formed in an upper portion of the can body 11, and two dust-containing gas inlet pipes 19 are connected from one pressurized fluidized bed boiler (not shown) to the upper space 18. Therefore, the high pressure generated in one pressurized fluidized bed boiler
The high-temperature dust-containing gas DG passes through the two dust-containing gas inlet pipes 19, enters the upper space 18 of the two dust removers, and furthermore, the outer cylinder filter block 14 and the inner cylinder filter block 15 of each dust remover. Each porous ceramic tube 1
3 flows into the interior of the porous ceramic tube 1.
3 passes from the inside to the outside, and the dust D is filtered by adhering to the inner wall of the porous ceramic tube 13.

On the other hand, a lower space 20 is formed in a lower portion of the can body 11, and a dust hopper 21 for storing dust D dropped from each of the filter blocks 14 and 15 is disposed in the lower space 20. An ash processing device (not shown) is connected to 21. Therefore, the dust D dropped from each of the filter blocks 14 and 15 is
The dust D accumulated in the dust hopper 21 is discharged out of the system by the ash treatment device.

The outer cylinder filter block 14 and the inner cylinder filter block 15 attached to the outer cylinder part and the inner cylinder part of the can body 11 are supplied with the filtered clean gas CG respectively.
An outer tube outlet tube 22 and an inner tube outlet tube 23 to be taken out of the apparatus are connected. The outer pipe 22 and the inner pipe 2
Numeral 3 is joined at its tip and connected to a clean gas outlet pipe 24. The two clean gas outlet pipes 24 are merged into one and then connected to a gas turbine generator (not shown), where the clean gas outlet pipe 24 is connected. Gas CG is supplied.

The outer cylinder outlet pipe 22 and the inner cylinder outlet pipe 23 are backwashed to remove dust D that has been removed by the outer cylinder filter block 14 and the inner cylinder filter block 15 and adhered to the inner surface of each porous ceramic tube 13. Backwash nozzle 2 for dropping
5 and 26 are respectively mounted.

Each of the backwash nozzles 25 and 26 is connected to the backwash air pipe 2.
9 is connected to the backwash air buffer tank 32, and near the connection between each backwash nozzle 25, 26 and the backwash air pipe 29, a fully open / closed type backwash valve 27, 28 and an opening degree upstream thereof. Backwash valve front valves 33 and 34, which are special control valves that can be arbitrarily set, are provided.

The backwash air buffer tank 32 and the backwash air compressor 30 are connected by a compressor outlet pipe 31, and the internal pressure of the backwash air buffer tank 32, as described with reference to FIG. The backwash air compressor 30 automatically starts when the air pressure falls below a low air pressure so as to maintain the pressure within a preset pressure range, and the backwash air compressor 30 when the air pressure exceeds a high air pressure.
Is automatically stopped, and the necessary backwash air is supplied to the backwash air buffer tank 32. Each of the filter blocks 14, 15 has a special differential pressure measuring device 35, which can measure the instantaneous peak value of the backwash pressure during backwash.
36 are attached.

The backwashing is performed individually for each filter block 14, 15; first, with respect to the first filter block, the backwash valve front valve 33 or 34, which is normally fully closed, opens at a certain opening degree, Normally the backwash valve 27 which is fully closed
Or 28 is fully closed immediately after fully opened for 0.5 seconds to 1.0 second, and a high external pressure is applied to the outer surface of the porous ceramic tube 13 in a pulsed manner to remove dust D adhering to the inner surface of the porous ceramic tube 13. Remove it.

At this time, the backwash pressure is measured by the differential pressure measuring device 35 or 36 attached to the backwashed filter block, and the measured backwash pressure is set in the can body 11 as shown in FIG. If the operating gas pressure is higher than the preset range of the appropriate backwash pressure, the opening of the backwash valve front valve is automatically reduced according to the calculation result of the computer at that time.

When the measured backwash pressure is lower than the proper backwash pressure range, the opening of the backwash valve front valve is automatically opened according to the calculation result of the computer at that time, and the next time the filter block is opened. Backwashing is performed with the opening of the backwash valve front valve after this change.

When the backwash pressure at this time exceeds a preset backwash pressure abnormally high as shown in FIG. 2 and falls below an abnormally low backwash pressure abnormally, an alarm is automatically issued and the operation is started. An abnormality is immediately conveyed to the member.

Thereafter, the same valve operation is sequentially performed at a predetermined interval for the other filter blocks, and the other filter blocks are backwashed. When air is consumed by backwashing of a certain filter block and the inside pressure of the backwash air buffer tank 32 becomes lower than the set pressure range, the backwash air compressor 30 is automatically activated and the upper limit of the pressure range is set. Stops automatically when it reaches, and prepares for the next filter block backwash.

As described above, the high-pressure and high-temperature dust-containing gas DG generated in the pressurized fluidized-bed boiler is supplied to the dust-containing gas inlet pipe 19.
Accordingly, the gas is guided to the upper space 18 of the can body 11 and flows into the inside of each of the porous ceramic tubes 13 of the outer cylinder filter block 14 and the inner cylinder filter block 15, and the gas passes through the wall of the porous ceramic tube 13 from the inside. The dust D passes outward and is filtered by attaching to the inner wall of the porous ceramic tube 13.

The clean gas CG from which the dust has been removed flows into the clean gas outlet tube 24 from each of the filter blocks 14 and 15 through the outer tube outlet tube 22 and the inner tube outlet tube 23, and the gas is removed by the clean gas outlet tube 24. Supplied to the turbine generator.

On the other hand, each of the porous ceramic tubes 1 of the outer cylinder filter block 14 and the inner cylinder filter block 15
The dust D adhering to the inner surface of the nozzle 3 is swept away by the backwash air intermittently and sequentially injected from the backwash nozzles 25 and 26 in a pulsed manner. The dust D that has been washed off is in the dust hopper 21.
And the dust D accumulated in the dust hopper 21 is discharged out of the system by the ash treatment device.

[0043]

As described above, the dust removing apparatus of the present invention is a backwash valve front valve capable of arbitrarily setting an opening degree before a fully opened / fully closed backwash valve of a backwash air piping line, A backwash pressure measuring device for measuring the backwash pressure and a control device for automatically adjusting the opening of the backwash valve front valve so that the backwash pressure does not greatly deviate from a proper value range during operation.

As a result, the dust removing apparatus of the present invention is automatically controlled so that the backwash pressure of each filter block does not greatly deviate from the appropriate range.
Even if the degree of contamination of the filter element, gas temperature, boiler load, type of fuel (coal) used, ash properties, ash concentration, etc. change over time, it should always deviate significantly from the appropriate backwash pressure range. You can drive without.

Therefore, in the dust removing apparatus of the present invention, the filter component parts are damaged when the backwash pressure is too high, and the filter differential pressure is abnormally high due to the reduced dust removing ability when the backwash pressure is too low. It is possible to prevent problems such as operation stoppage caused by the operation.

During the operation, if the backwash pressure exceeds a preset backwash pressure abnormally high or falls below an abnormally low backwash pressure abnormally due to an unexpected situation, an alarm is automatically issued. According to the method described above, the operator can quickly notice the abnormality and take a countermeasure / measure at an early stage, thereby preventing occurrence of a major trouble.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a dust removal device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of setting an appropriate backwash pressure range, an abnormally high backwash pressure, and an abnormally low backwash pressure in the present invention.

FIG. 3 is a schematic configuration diagram of a conventional dust remover mounted on one can of a pressurized fluidized-bed boiler.

FIG. 4 is a schematic view of a cross section taken along line XX of FIG. 3;

FIG. 5 is a schematic view of a cross section taken along line XI-XI in FIG. 3;

FIG. 6 is a diagram showing an example of setting a backwash air buffer tank pressure in the conventional and the present invention.

[Explanation of symbols]

 Reference Signs List 11 can 12 cylindrical partition 13 porous ceramic tube 14 outer filter block 15 inner filter block 18 upper space 19 dust-containing gas inlet tube 20 lower space 21 dust hopper 22 outer tube outlet tube 23 inner tube outlet tube 24 clean gas outlet Pipe 25, 26 Backwash nozzle 27, 28 Backwash valve 29 Backwash air pipe 30 Backwash air compressor 31 Compressor outlet pipe 32 Backwash air buffer tank 33, 34 Backwash valve front valve 35, 36 Differential pressure measuring device

Claims (2)

[Claims] 1. A dust removing apparatus comprising two or more filter blocks made of a honeycomb or cylindrical porous ceramic body having a dust removing function and mounted in a cylindrical can arranged substantially vertically. Backwash air compressor, backwash air buffer tank, backwash air piping line from the backwash air buffer tank to each of the above filter blocks, fully open / fully closed backwash valve installed in each backwash air piping line And a backwash valve front valve that can arbitrarily set an opening provided upstream of the backwash valve, a differential pressure measurement device that measures an instantaneous backwash pressure during backwash for each of the filter blocks, and During operation, a control device for automatically adjusting the opening of the backwash valve front valve so that the backwash pressure of each filter block does not significantly deviate from the range of the appropriate value, the control device includes the reverse The backwash air compressor is controlled to start and stop so that the internal pressure of the wash air buffer tank is maintained within a preset pressure range with respect to the operating gas pressure, and the pressure is measured by the differential pressure measurement device. When the backwash pressure of each filter block is higher than a preset backwash pressure range, the opening of the backwash valve front valve is narrowed, and when the backwash pressure is lower than the appropriate backwash pressure range, the backwash valve is closed. A dust remover characterized by being configured to open a valve. 2. The dust removing apparatus according to claim 1, wherein the back pressure measured by the differential pressure measuring device for each back washing of each of the filter blocks exceeds a predetermined back washing pressure abnormally high and a predetermined reverse washing pressure. A dust remover with a maintenance device that automatically issues an alarm when the washing pressure falls below an extremely low level.