JP3288104B2 - High-temperature gas dust remover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power plant using a pressurized fluidized bed boiler and a coal direct combustion apparatus (Coal Di).
TECHNICAL FIELD The present invention relates to a high-temperature gas dust remover incorporating a filter made of porous ceramics suitable for dust removal of a high-temperature dust-containing gas discharged in a combustion process such as heat recovery or a coal gasification plant.

[0002]

2. Description of the Related Art The technology relating to a high-temperature gas dust removal device incorporating a ceramic filter is a next-generation high-efficiency and clean (exhaust gas having low NO _x and low SO _x ) coal utilization technology. It is regarded as a key technology for realizing a coal gasification plant and a power generation plant using a pressurized fluidized-bed boiler, and efforts are being made in many countries around the world.

[0003] When a dust remover is incorporated in these plants and used, special attention should be paid to the behavior of dust at high temperatures. That is, since the viscosity coefficient of gas generally increases as the temperature rises, dust is strongly affected by the flow of gas at high temperatures, and the main dust contained in the dust removal chamber (the part where solid-gas separation is performed in the dust removal device) Even when the gas flow is configured to be generally downward, a part of the fine dust flows against the gravity on the turbulent gas flow and does not easily fall into the hopper.

[0004] In the actual plant, the disturbances in the disturbance or upstream system or downstream system due to operating conditions of the filtration apparatus itself, the flow of the dust chamber is constantly changed, the turbulent flows with various offshoot It exists inside the dust remover.

As a result, the following problems occur in the dust removing device. a. Dust Bridging: one end thereof is closed tubular ceramic filters called candle type filtration is used and devices, a phenomenon seen in a cross-flow type filtration apparatus plate-shaped ceramic filter is used, sideways or Even if the ceramic filter is backwashed due to the presence of an upward flow, dust does not fall to the lower hopper and adheres to the nearby ceramic filter again. This is a phenomenon in which a part of the passage on the dust-containing gas side of the ceramic filter is finally blocked by the accumulated dust, or a part of the filtration surface of the ceramic filter is covered with a thick dust accumulation layer.

Therefore, when the bridging of dust occurs, the effective filtration area of the filter gradually decreases, and the processing capacity of the dust removing device decreases. However, when removing the combustion gas from the pressurized fluidized bed boiler, unburnt components contained in the dust that bridging is often ignited, burned, resulting in catastrophic damage, such as ceramic filters in the filtration apparatus from being damaged by thermal stress (cracking or breakage).

Further, in the dust removal processing of the synthesis gas in the coal gasification plant, switching from a state of being substituted with a non-oxidizing gas immediately after the shutdown to the air, or oxidizing atmosphere containing oxygen at relaunch operation When these gases are present in the dust remover, unburned components in the bridging dust ignite and cause fatal thermal stress damage to the ceramic filter of the dust remover.

B. When the load of the plant fluctuates, a large amount of unburned components including soot are discharged into the combustion gas, deposit on the surface of the ceramic filter, and then ignite and abnormally burn. For example, when removing the combustion gas from a pressurized fluidized-bed boiler, if an attempt is made to increase the boiler load from a low load state, a large amount of unburned components are generated despite a high oxygen concentration, and a large amount of dust is contained in the dust. Combustion gases containing soot (sometimes as high as 30%) and containing more than 1000 ppm of carbon monoxide may be generated.

In a pressurized fluidized bed boiler, a method of introducing a combustion gas, which has been coarsely dusted by a cyclone, into a dust removal device having a built-in ceramic filter has been generally adopted, but the cyclone has a sudden increase in dust concentration in the dust-containing gas. In such a transient state, the dust overflows and does not exert a sufficient dust removing function.

Therefore, the dust containing a large amount of unburned components that has passed through the cyclone reaches the ceramic filter of the dust removing device. At this time, since the dust concentration in the dust-containing gas increases to 5 to 10 times the dust concentration in the steady state, the increasing gradient of the filtration differential pressure also increases to 5 to 10 times that in the steady state.

[0011] In the candle type dust remover, since the cross-sectional area of the dust containing gas side of the dust removing chamber is large, it is difficult to make the flow of the dust containing gas a complete downward flow. They tend to adhere in large quantities, and there is a high risk of ignition if the dust contains a large amount of unburned components.

A tubular filter is incorporated as a ceramic filter, and the inside of the container is partitioned by a plurality of horizontal tube sheets.
A plurality of tubular ceramic filters are held at their ends by a tube sheet, and the dust-removing device is configured so that the dust-containing gas flows downward through the inside of the tubular ceramic filters (Japanese Patent Publication No. 63-40567, Japanese Patent Publication No. 2-22689, Japanese Patent Publication No. 3-24251, Japanese Patent Publication No. 3-61076, Japanese Patent Application Laid-Open No. 1-3
No. 03397, etc., describes this type of dust remover, which is hereinafter referred to as a tube type dust remover). Have been.

Therefore, under normal operating conditions, the dust does not accumulate thickly on the filtration surface of the tubular ceramic filter, the absolute amount of the unburned component that flies does not fluctuate greatly, and always less than about 10% in the dust. Contains unburned components,
As long as this is burning slowly and steadily, there is no problem such as damaging the tubular ceramic filter.

However, when a dust-containing gas containing a large amount of unburned components is introduced in a short time even in a tube-type dust removing device, the dust is formed on the inner surface of the lower end of the tubular ceramic filter having a downward gas flow rate close to zero. Will accumulate in large quantities, and this dust will ignite and burn at once, causing the temperature inside the tubular ceramic filter to rise rapidly, and the temperature difference with the outside of the tubular ceramic filter exceeding the allowable temperature difference of the ceramic material, A phenomenon occurs in which the ceramic filter is damaged by thermal stress.

[0015] That is, in the lower end of the tubular ceramic filter is affected by the distribution of the pressure and velocity of the gas inlet chamber of the vessel, variations occur in the flow rate of the dust containing gas in each tubular ceramic filters, etc. flow velocity photons zero tubular It has become clear that there are ceramic filters and tubular ceramic filters in which gas flows back from inside the hopper.

Further, the distribution of the pressure and the velocity in the gas inlet chamber changes every moment irrespective of the tube type dust remover or the candle type dust remover due to the fluctuation of the upstream of the plant, which is disturbed in the dust remover chamber and the hopper. It has become clear that this is one of the causes of gas flow.

[0017] In the tube type dust removing device,
No. 24251 proposes a dust removal method in which a dust-containing gas is extracted from a hopper and returned to the upstream side for the purpose of reducing the filtration pressure difference and the frequency of backwashing.

This proposal is a useful method that can solve the above-mentioned problems in both the tube type dust remover and the candle type dust remover. However, if the amount of dust-containing gas to be removed is very large, it is necessary to remove the dust. A large amount of dust-containing gas is emitted, and a corresponding power is required to recirculate the gas upstream.

In order to transfer a gas having a high dust content, it is most practical to use an ejector driven by steam or high-pressure air. However, the efficiency of an ejector using compressed air is at most 4%, and it is not realistic to secure the gas recirculation amount recommended in the above proposal with a dust removal device having a large processing gas amount.

In particular, in the case of the candle type dust remover, since the cross-sectional area of the flow path of the dust-containing gas in the dust removal chamber is large and the required gas reflux amount is larger than that of the tube type dust remover,
Utility usage, such as compressed air, has a significant effect on plant efficiency.

To obtain the same effect as the reflux, it is effective to extract a part of the dust-containing gas together with the dust and take it out to the external system. However, since the extraction of a large amount of the dust-containing gas affects the efficiency of the plant, In a power plant, the amount of dust-containing gas extracted is suppressed to 1 to 2%. Therefore, in this method, a sufficient recirculation effect cannot be obtained, and when a large amount of dust containing unburned components such as soot comes in at the time of load change or the like, it is inevitable that a large amount of dust is deposited on the surface of the ceramic filter.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dust-containing gas hopper suitable for a high-temperature pressurized combustion process such as a pressurized fluidized-bed boiler or a dust removal treatment of exhaust gas from a coal gasification plant or the like. It is an object of the present invention to provide a high-temperature gas dust removing apparatus provided with practical means capable of extracting from the section and returning the dust to the dust-containing gas introduction section with little energy consumption.

[0023]

The high-temperature gas dust removing apparatus of the present invention has a built-in ceramic filter in a container, and a backwash means for regenerating the ceramic filter by removing dust trapped by the ceramic filter. A dust removal device, wherein the lower portion of the container is a hopper portion for collecting dust that has been blown off, wherein a dust-containing gas introduction portion of the container is provided.
The diffuser is attached, or Tsude Ifuyuza gas passage communicating inlet and the hopper portion (divergent tube) is provided, a portion of the dust-containing gas in the hopper is dirty gas introduction container via a gas passage and the diffuser It is characterized in that it is configured to return to the section.

The gas flow velocity in the pipe for introducing a dust-containing gas inlet to the dust-containing gas filtration apparatus, to avoid adhesion and accumulation of dust into the pipe, which is set larger within a range that does not cause erosion, In the dust removing apparatus of the present invention, the most part of the introduced gas dynamic pressure is converted into static pressure by the diffuser to increase the pressure on the dust removing chamber side, and the obtained differential pressure causes the dust containing gas to pass from the hopper to the gas passage. A means is provided for refluxing the dust upstream of the dust removal device.

More specifically, a dust-containing gas introducing portion of the container ,
For example , a diffuser is provided near the gas inlet, and a gas passage communicating with the hopper is provided at a low static pressure portion at the inlet of the diffuser. If it has such a recirculation means, the design of the dust containing gas introduction pipe, the type of filtration apparatus, capable of coping with variations in the operating conditions of the plant in kind and upstream and downstream of the application to the plant, including the hopper The amount of recirculation of the dust-containing gas to the dust gas inlet can be secured.

[0026] In this case, the diffuser means a thing to exert pressure recovery function, does not mean only the divergent diffusion tube. For example, large R to the gas inlet port to the container
(R) may be provided, or an orifice is provided at the gas inlet to the container, and the pressure is low immediately downstream of the orifice,
The gas flow may be expanded downstream to recover the pressure by itself.

In the dust remover for high-temperature dust-containing gas of the present invention, when the dust remover is a tube-type dust remover, the recirculation rate of the dust-containing gas from the hopper to the dust-containing gas inlet is introduced into the dust remover. It is preferably 3 to 15% of the dust-containing gas. When the dust remover is a candle-type dust remover, it is preferable to set the recirculation rate of the dust-containing gas to 5 to 25%.

When the recirculation amount of the dust-containing gas is less than 3% (6% for the candle type dust remover), the effect of preventing abnormal accumulation of dust on a part of the surface of the filter tube is small.
When it is more than 0%, or is easy to wind the dust from the hopper section, there is an impact, such as energy consumption is increased.

In the preferred high-temperature gas dust remover of the present invention, the ceramic filter is a tubular ceramic filter, the interior of the container is partitioned by a plurality of horizontal tube sheets, and the dust- containing gas introduction section above the uppermost tube sheet. Is provided with a gas inlet chamber, a plurality of tubular ceramic filters are respectively held at their ends by a tube sheet, and the dust-containing gas is configured to flow inside the tubular ceramic filter.

In the tube type dust removing apparatus, since the flow path of the dust containing gas in the dust removing chamber is provided inside the filter tube, the cross sectional area of the flow path of the dust containing gas is small, and a relatively small amount of the dust containing gas is used. When dust is returned from the hopper to the gas inlet chamber and dust-containing gas containing a large amount of dust is introduced into the dust removing device, a large amount of dust is accumulated on the filtration surface and the dust-containing gas flow path due to dust is generated. closing the can prevent the, wear problems dust containing unburnt component is thermally damage the filter tubes unburnt components be introduced therein is ignited near the surface of the filter tubes of a large amount of dust remover in avoidance .

In another preferred embodiment of the present invention, the ceramic filter is a tubular ceramic filter having one end closed, and a plurality of tubular ceramic filters are mounted substantially vertically below or above the clean gas header. The unit is disposed in the container, and the dust-containing gas is configured to be removed while sequentially descending from the top of the dust removal unit.

When the high-temperature gas dust remover is a candle type dust remover in which such a dust removing unit is provided in a container, the cross-sectional area of the dust containing gas in the dust removing chamber is large.
It is necessary to recirculate a considerable amount of dust-containing gas from the hopper to the dust-containing gas inlet.

In the dust remover for high-temperature gas of the present invention, the dust-containing gas sent at a high flow rate and having a low static pressure is caused to flow through the diffuser to convert the dynamic pressure into a static pressure, thereby increasing the pressure in the container of the dust remover. In addition, a suction port is provided at a low static pressure point at the diffuser inlet, and the dust-containing gas in the hopper is sucked through the gas passage, and the dust-containing gas is returned to the dust-containing gas introduction section of the dust removing device. Therefore, utilities such as compressed air
At reflux a sufficient amount of the dust containing gas without particular consume I
Can Ru.

In another preferred high-temperature gas dust-removing device of the present invention, a plurality of dust-removing units are vertically and / or horizontally arranged in a container. Large Tiered with multiple dust removal units arranged in layers in a container
If the type of candle type filtration apparatus, a number are places where stagnant flow of gas into the dust-containing gas space that exist, in filtration apparatus of the present invention, sufficient amounts of a plurality of suction ports dust-containing gas can be recirculated to the dust containing gas introduction section from the hopper unit, wear do not tend large practical filtration apparatus a large amount of dust in the portion of the filtration surface of the filter tube is deposited in configuration.

Another preferred high-temperature gas dust remover of the present invention has an ejector configuration in which a throttle pipe or an ejector nozzle is attached upstream of the diffuser inlet, and a suction port is arranged at the diffuser inlet. In other words, the ejector is located upstream of the diffuser inlet.
Or a combination of ejector nozzles, which inlet in the inlet portion of the diffuser is provided, the configuration of the diffuser and a portion of the ejector, even when the dynamic pressure with the dust-containing gas introduced is small, sufficient suction capacity of the dust-containing gas from the gas passage kills with securing.

Generally, the dust-containing gas is introduced into the dust-containing gas introduction portion of the dust removing device.
In spite of the fact that the flow velocity in the introduction pipe for introducing gas is set to be relatively high, there is a known example in which a diffuser is provided in the dust-containing gas introduction section of a dust remover for the purpose of restoring the static pressure. Absent. For this reason, compared with the conventional design without a diffuser, even if a throttle pipe is provided on the upstream side of the diffuser and the ejector configuration is used, the increase in pressure loss in the dust remover is suppressed to at most the pipe resistance required for gas recirculation. It can control.

In another preferred high-temperature gas dust remover of the present invention, the container is a pressure container, and the gas passage is provided inside the pressure container.

Since the gas passage for returning the dust-containing gas from the hopper to the dust-containing gas introduction portion of the dust removing device can be shortened by being provided inside the pressure vessel, it is necessary for the return of the dust-containing gas. -out small Kude the driving force that, since it is not necessary to provide a passage to the outside of the container without the need of applying insulation on the outside of the passage, less loss of heat energy from the surface of the passage, a pipe to withstand pressure Since there is no need for addition, the cost required for constructing the apparatus can be reduced.

The high-temperature gas dust remover of the present invention is a pressurized fluidized-bed boiler, which is considered to be a high-efficiency and clean (a small amount of SO _X and NO _X emitted) energy utilizing coal in the future. there <br/> especially in good suited for power plant was built. In this type of power plant, a high power generation efficiency is obtained by using a steam turbine using boiler steam and a gas turbine driven by combustion gas, and the dust removal device uses a pressurized combustion system. It is used for removing dust in combustion gas which is harmful when the gas is used for driving the gas turbine (wears the gas turbine and shortens its life).

The dust removing apparatus for high-temperature gas of the present invention can be used for dust-removing high-temperature dust-containing gas containing a large amount of unburned components temporarily generated when, for example, increasing the boiler load.
By preventing a large amount of dust containing unburned components from being deposited on the filtration surface of the ceramic filter, unburned components in the deposited dust are less likely to ignite, and are incorporated even if ignited and burned. It is possible to prevent the ceramic filter from undergoing catastrophic thermal stress damage.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the high-temperature gas dust removing apparatus of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a longitudinal sectional view showing an embodiment in which the high-temperature gas dust remover according to the present invention is applied to a tube type dust remover. In FIG. 1, reference numeral 1 denotes a tube type dust remover, 2 denotes a pressure vessel, 3 denotes a tubular ceramic filter (filter pipe), 5a, 5b, 5c, and 5d support each filter pipe and extend the inside of the pressure vessel in a horizontal direction. (5a and 5d partition between the dust-containing gas space and the clean gas chamber, and the other tube plates partition between the clean gas chambers). , A hopper section, 8 a diffuser, 9a, 9b and 9c upper, middle and lower clean gas chambers, and 10 a gas inlet. Although a heat insulating material is lined inside the pressure vessel 2, this is omitted in FIG.

Reference numerals 11a, 11b, and 11c denote a clean gas outlet pipe also serving as a diffuser of an ejector for blowing backwash gas into the upper, middle, and lower clean gas chambers, 12, a clean gas outlet, and 13 withdrawing from the hopper. Gas passages 14a, 14 consisting of heat-resistant metal tubes through which the dust-containing gas to be discharged passes
Reference numerals b and 14c denote ejector nozzles for ejecting compressed air for backwashing to respective clean gas outlet pipes, 15 denotes a skirt provided at the lower end of the filter pipe 3, and 16 denotes a suction port in which the gas passage 13 is open to the hopper. A mouth 17 is an ejector of which the diffuser 8 is a part, and 18 is an ejector nozzle attached to the gas inlet 10.

Here, the heat-resistant metal pipe of the gas passage 13 also serves as a support for supporting the diffuser 8, 19 is an inlet of the diffuser 8, and 20 is an inlet for sucking dust-containing gas from the hopper 7 through the gas passage 16. It is. This gas passage 1
Of the three, a portion passing through the clean gas chamber may be used as a filter tube, and the filter tube may be used as a gas passage.

In the dust removing apparatus shown in FIG. 1, the ejector nozzle 18 attached to the gas inlet 10 is separated in the middle so as to absorb the displacement caused by the thermal expansion of the heat-resistant metal tube constituting the gas passage 13, and the fitting structure. It has been. Also,
The dust-containing gas flows from the gas inlet 10 in the direction of the arrow, and is ejected by the ejector nozzle 18 into the inlet 19 of the diffuser 8.
A low static pressure is formed by increasing the speed, and the dust-containing gas in the gas passage 13 is sucked from the suction port 20 provided at the inlet portion 19 of the diffuser having the smallest diameter, and the static pressure is gradually recovered in the diffuser 8. and, the gas inlet chamber 6 in 1000mmAq high static pressure if example preparative was than static pressure of the diffuser inlet section 19
Flows into.

In the gas inlet chamber 6, a maximum of 70m is inevitable.
Since a static pressure distribution having a difference of about mAq is generated, there is some variation in the flow velocity of the gas flowing into each filter tube 3. Further, since the static pressure and the flow rate of the dust-containing gas flowing into the gas inlet 10 fluctuate from moment to moment, the static pressure and the velocity vector in the gas inlet chamber 6 change accordingly, and each filter pipe is changed. The flow rate of the gas flowing into 3 is also changing.

The dust-containing gas distributed to each filter tube 3 is:
The gas is filtered on the inner surface of the filter tube 3 while descending inside the filter tube 3 and becomes a clean gas, and the clean gas chambers 9a, 9
b, 9c. The gases that have left the clean gas chambers 9a, 9b, 9c are clean gas outlet pipes 11a, 11b, 11 respectively.
, and is sent to the downstream system from the clean gas outlet 12.

Since the dust-containing gas flowing inside the filter tube 3 bleeds outward while flowing through the filter tube 3, its descending speed gradually decreases downward, and the filter tube has a different speed for each filter tube. Flows into the hopper section 7 from below the skirt 15 attached below.

If the static pressure distribution in the gas inlet chamber 6 is uniform and there is almost no variation in the ventilation pressure loss of the filter tube, the dust-containing gas should flow into the hopper 7 from the lower end of each skirt 15 at almost the same speed. Yes, but in reality this is not the case. The skirt 15 is provided because the dust falling from the lower end of the filter tube 3 allows the dust 1
6 so that the dust accumulated on the bottom of the hopper portion 7 is preferably made long as long as it does not wind up.

In consideration of the gas pulsation in the hopper 7, the distance from the tip of the skirt 15 to the suction port 16 of the gas passage 13 is preferably 100 mm or more, more preferably 200 mm or more. The sucked dust-containing gas passes through the gas passage 13 from the suction port 20 to the diffuser 8.
And is returned to the gas inlet chamber 6.

If a static pressure difference of 300 to 1000 mmAq is provided between the outlet and the inlet of the diffuser 8, the dust-containing gas introduced into the dust remover varies depending on the design of the tube-type dust remover, the type of the applied plant, and the like. About 7 to 15% of
Can be the reflux, Ru can be ensured lowering speed of the dust containing gas at the lower end of all filter tubes.

When the introduction of the dust-containing gas into the dust removing device starts and dust accumulates on the inner surface of the filter tube 3, the gas inlet chamber 6
And the filtration pressure difference between the clean gas outlet pipes 11a, 11b and 11c starts to gradually increase. The filtration pressure difference is usually maintained at a predetermined low pressure difference range by performing backwashing at regular time intervals.

The backwashing of the filter pipe is performed by opening and closing a control valve that operates at a high speed to thereby supply compressed air to the ejector nozzle 1.
4a, 14b, and 14c, the pressure in the corresponding clean gas chambers 9a, 9b, 9c is made higher than the pressure on the dust-containing gas side so that the gas flows backward from the outside of the filter tube 3 to the inside. Is sequentially performed by removing the dust accumulated on the surface.

The opening time of these control valves (from fully closed to fully open )
The time required until the next full closing after passing is usually 0.1 to 0.1.
5 seconds. Particularly important for effective backwashing are the time required from fully closed to fully open and the holding time in the fully open state.If the time required from fully closed to fully open is too long, the pressure outside the filter tube and the pressure inside the filter tube Difference (hereinafter referred to as "backwash differential pressure") cannot be made sufficiently large, and if the holding time in the fully open state is too short, the backwash differential pressure rise will be insufficient and regeneration of the filtration function of the dust removal device will be incomplete. Becomes

If the regeneration by backwashing becomes incomplete, the dust removal capability becomes unstable, for example, the filtration differential pressure tends to increase gradually.
The conditions for backwashing include the type and size of the control valve, the pressure of compressed air,
There is an optimum valve opening time depending on the thickness of the compressed air pipe, the effective filtration surface area of the filter pipe for backwashing, the dead volume outside the filter pipe (the capacity of the clean gas chamber), and the like.

[0056] backwash rear at a fixed time interval (for example 15 minutes) 9a, 9b, may be carried out intermittently in a clean gas chamber 60 seconds or less each interval in the order of the 9c, 9
The clean gas chambers a, 9b and 9c may be backwashed at regular time intervals (for example, every 5 minutes).

FIG. 2 is a longitudinal sectional view showing an example in which the high-temperature gas dust remover of the present invention is applied to a so-called Tiered type candle type dust remover. 3 is an A-A sectional view of FIG. 2, FIG. 2 Ru sectional view taken along line B-B der in Fig.

In FIG. 2, reference numeral 31 denotes a candle type dust remover, 32 denotes a gas inlet, 33 denotes a clean gas outlet, 34 denotes a pressure vessel, 35 denotes a heat insulator attached to the inside of the pressure vessel 34, and 36 denotes one end closed. Filter tube 37, a clean gas header, 38 a backwashing ejector (not shown) inside, and a dust removing unit in which a plurality of filter tubes 36 are mounted substantially vertically below the clean gas header 37.
9 is provided inside the pressure vessel 34 and includes a dust removal unit 38.
And a tube sheet that separates the dust-containing gas space and the clean gas space 51 from each other.

Reference numeral 40 denotes an ejector nozzle for back washing inserted in each dust removing unit, and 41 denotes a gas inlet 32.
A guide tube having a flow direction of the dust-containing gas flowing downwardly along the filter pipe 36, 42 is a hopper portion, 43 is a gas passage, 44 is a diffuser, and 45 is a gas passage opening to the hopper portion 42. Reference numeral 43 denotes an inlet, reference numeral 46 denotes a diffuser inlet, reference numeral 47 denotes a throttle pipe provided on the upstream side of the diffuser inlet 46, and reference numeral 48 denotes an inlet opening to the diffuser inlet 46 for sucking dust-containing gas from the gas passage 43. And 50, a dust removal chamber surrounded by the guide cylinder 41.

In FIG. 2, the dust-containing gas is supplied to the gas inlet 32.
The dust further flows into the dust removal device 31, is turned from the upward flow to the downward flow by the guide cylinder 41 as shown by the arrow, flows into the upper part of the upper dust removal unit, and enters the dust removal chamber 50. Here, the dust-containing gas is supplied to each filter pipe 36 of the upper two sets of dust removal units.
And reaches the hopper 42. Part of the dust-containing gas is returned from the suction port 45 to the diffuser inlet 46 through the gas passage 43, and is sent to the upper part of the dust-removing chamber 50 together with the dust-containing gas introduced into the dust-removing device.

By circulating the dust-containing gas in this manner, the dust-removing unit 3 in the dust-removing chamber 50 is provided in this dust-removing device.
The gas flow in the horizontal direction between 8 is suppressed, and the descending gas flow is ensured also at the lower end of the filter pipe of the lowermost dust removing unit where the gas descending speed is minimized in the dust-containing gas side space.

On the other hand, the clean gas filtered by the filter tube 36 rises inside the filter tube 36 and enters the clean gas header 37, is collected in the clean gas space 51, and is discharged to the clean gas outlet 33.
Is sent out to the downstream system.

In the backwashing, air is sequentially ejected from the ejector nozzle 40 for each dust removing unit 38 so that the gas pressure in the clean gas header 37 becomes higher than the pressure on the dust-containing gas side, and the gas flows back to the filtration wall of the filter tube 36. This is done by having

The ejection of air from the ejector nozzle 40 normally takes a valve opening time (the time required from the fully closed state to the next fully closed state through the fully opened state) to be 0. 0, as in the case of the tube type dust remover.
This is performed by a control valve (not shown) set at 1 to 0.5 seconds. The dust removed from the upper dust removing unit 38 by the backwash is sent downward by the gas flow without staying in the upper space of the dust removing chamber 50, and a part of the dust is captured by the lower dust removing unit 38, but most of the dust is captured. Falls into the hopper 42.

When the dust removing units 38 in either of the right and left rows shown in FIG. 3 are backwashed, the backwash gas is jetted from the dust removing units, and the gas flow in the dust removing chamber 50 and the hopper 42 is instantaneously disturbed. Since the dust-containing gas is constantly extracted from the suction port 45, the gas immediately returns to the original flow state.

FIG. 4 is a longitudinal sectional view of another embodiment of the tube type dust remover of the present invention. In the figure, reference numeral 21 denotes an orifice, 22 denotes an R (R) portion, 23 denotes a gas passage, and 25 denotes a gas passage.
Is a suction port, and 28 is a suction port. That is, the orifice 21 and the R (R) portion 22 are provided in the gas inlet 10, and the suction port 28 is opened immediately downstream of the orifice 21, and the function of the diffuser is provided by the orifice 21 and the R (R) portion 22. It has been demonstrated. As other variations, various configurations can be considered within the scope of the present invention, such as forming an ejector in a space around the guide cylinder.

FIG. 5 is a longitudinal sectional view of another embodiment of the candle type dust remover according to the present invention. In the figure, reference numeral 52 denotes an R portion provided at the gas inlet 32. In this case, even if the orifice is not provided, the diffuser function is exhibited only by the R portion.

Test Examples Examples of test results when the dust remover according to the present invention is applied to a three-stage tubular dust remover provided in a pressurized fluidized bed boiler and when it is not applied are shown below .

1) When the dust removing device of the present invention is not used (the dust removing device of FIG. 1 is omitted the recirculation means of the dust-containing gas): At the same time as the boiler load starts to increase, the gradient of the filtration pressure difference (unit) The increase in filtration pressure difference per hour) is 7 times, the oxygen concentration is rapidly reduced, and a large amount of unburned components are generated and flying (estimated). After 5 minutes, the boiler load is reduced to 75%. Reached.

One minute later, the temperature of the lower clean gas chamber, which was the same as the temperature of the other clean gas chambers, started to rise sharply higher than the temperature of the other clean gas chambers. After the temperature of the clean gas chamber became higher by 40 ° C., the temperature began to drop. From this experience, it was determined from the experience so far that dust containing unburned components adhering to the inner surface of the filter tube in the lower clean gas chamber was burning.

Immediately thereafter, it was observed that the filtration differential pressure dropped sharply and black smoke was emitted from the exhaust stack downstream. The operation of the boiler was stopped immediately, and the inside of the dust removal device was inspected. One of the lower filter tubes (made of cordierite ceramic, having an outer diameter of 17 cm, an inner diameter of 14 cm, and a length of 3 m) was approximately 70 cm from the bottom. The missing filter tube was broken into a number of small pieces. It was determined that the filter tube was damaged by thermal stress due to the burning of unburned components in the dust from the crack condition and other factors.

2) When the dust remover of the present invention was used: The dust remover having the structure shown in FIG. 1 was operated by returning 10% of the flow rate of the dust-containing gas flowing into the gas inlet from the hopper to the gas inlet. . Even if the boiler load was increased and the load was switched from light oil combustion to coal combustion and the load was set to 75%, the temperature inside the filter tubes in all lower clean gas chambers was stable as in the case of light oil combustion. Even when the boiler load was increased, the filtration differential pressure and the temperature in the lower-stage clean gas chamber passed without any particular increase compared to the temperatures in the other stages of the clean gas chamber. After that, the boiler load was increased from 75% to 100%, and the operation was stopped for a total of about 48 hours.

As a result of opening and inspecting the clean gas chamber at the lower stage of the dust remover, no abnormality was found in the filter tube. Also, no trace of accumulation of a large amount of dust was found on any part of the filter tube in the dust removing device.

[0074]

The high-temperature gas dust remover according to the present invention can be used for dust removal of high-temperature dust-containing gas generated in a power plant using a pressurized fluidized-bed boiler, a combustion process such as a direct coal combustion device, or a coal gasification plant. Even if a dust-containing gas having a high dust concentration is introduced, there is no phenomenon that a large amount of dust is deposited on the filtration surface of the ceramic filter, and even if dust containing a large amount of unburned components such as soot is introduced. The utility value in the energy industry is enormous because it can be used safely without suffering thermal stress damage to the pipes, and the future time for full-scale commercialization of these coal utilization technologies can be advanced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a high-temperature gas dust removing apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing another embodiment of the high-temperature gas dust remover of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a longitudinal sectional view showing another embodiment of the high-temperature gas dust remover of the present invention.

FIG. 5 is a longitudinal sectional view showing another embodiment of the high-temperature gas dust remover of the present invention.

[Explanation of symbols]

1: tubular type filtration apparatus 2, 34: pressure vessel 3,36: tubular ceramic filter (filter pipe) 3 5: heat insulating material 5a, 5b, 5c, 5d, 39: tubesheet 6: Gas inlet chamber 7,42: Hopper Parts 8, 44: Diffusers 9a, 9b, 9c: Clean gas chamber 10, 32: Gas inlet 11a, 11b, 11c: Clean gas outlet pipe 12, 33: Clean gas outlet 13, 23, 43: Gas passage 14a, 14b , 14c, 18, 40: ejector nozzle 15: skirt 16, 25, 45: inlet 17, 49: ejector 19, 46: diffuser inlet 20, 28, 48: inlet 21: orifice 22, 52: R (R) ) Part 31: candle type dust remover 37: clean gas header 38: dust remover unit 41: guide cylinder 47: throttle tube 50: dust remover chamber 51: clean gas Space

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-135517 (JP, A) JP-A-54-55872 (JP, A) JP-A-63-143920 (JP, A) JP-A-53-75575 (JP, A) JP-A-4-197418 (JP, A) JP-A-5-63612 (JP, U) JP-A-51-17874 (JP, U) Japanese Utility Model Application Hei 5-49019 (JP, U) Japanese Utility Model Application Showa 60-112332 (JP, U) Japanese Utility Model Application Hei 3-19522 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 46/24

Claims (2)

(57) [Claims] 1. A hopper which has a built-in ceramic filter in a container, and is provided with a backwash means for regenerating the ceramic filter by removing dust trapped in the ceramic filter, and a lower portion of the container collecting dust which has been removed. Dust removal device, which is a part, and introduces dust-containing gas into the container.
A diffuser is attached to the part, and a gas passage communicating with the inlet part of the diffuser and the hopper part is provided, and a part of the dust-containing gas in the hopper part is returned to the dust-containing gas introduction part of the container through the gas passage and the diffuser. A dust remover for high-temperature gas, characterized in that: 2. A cell La electrochromic filter is tubular ceramic filter, the gas inlet chamber is provided in the upper side of the uppermost tubesheet with the interior of the container is partitioned by a plurality of horizontal tube plate, a plurality of tubular ceramic filter The high-temperature gas dedusting device according to claim 1, wherein the dust-containing gas is held by a tube sheet at each end thereof so that the dust-containing gas flows inside the tubular ceramic filter.