Novel cloth bag dust removal system of desulfurizing tower

Abstract

The utility model relates to the technical field of flue gas treatment, and discloses a novel bag-type dust removal system of a desulfurizing tower, which comprises the desulfurizing tower and a bag-type dust remover, a flue gas outlet of the desulfurizing tower is connected with a flue gas inlet of the bag-type dust collector, an inverted cone ash hopper is arranged below the bag-type dust collector, and an ash hopper fluidizing tank is connected below the inverted cone ash hopper. The problems that dust-containing flue gas of an existing bag-type dust removal and desulfurization tower enters an inverted cone dust hopper to generate secondary dust raising, or flue gas at an outlet of the desulfurization tower is high in dust concentration, high in humidity but low in temperature, a bag is prone to being pasted, blocked and dewed, and meanwhile dust removal of a bag-type dust remover is not facilitated are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, in particular to a new bag dust removal system for a desulfurization tower. Background Technique

[0002] Disclosing the information of this background technique section is only intended to enhance the overall understanding of the utility model, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] At present, in order to meet the increasingly stringent environmental protection requirements, it is necessary to carry out ultra-low emission transformation on the tail gas discharged from the combustion in the boiler. After the construction of environmental protection facilities, the content of pollutants (nitrogen oxides, sulfur dioxide and dust) in the tail gas is reduced. That is, most of the domestic boiler tail gas pollutant discharge standards now implement "50355" ultra-low emissions, that is: it is required that the NOx in the flue gas be controlled at ≤50mg / Nm 3 、SO2 concentration ≤35mg / Nm3, and soot ≤5mg / Nm 3 。 In recent years, the CFB circulating fluidized bed semi-dry desulfurization and dust removal integrated process has stood out among many processes. The CFB circulating fluidized bed semi-dry flue gas desulfurization and dust removal integrated process is a desulfurization and dust removal technology suitable for China's national conditions. It is not only suitable for large-scale ones, but also an ideal method for the synchronous treatment of SO2 pollution and soot in medium and small industrial boilers. It not only has the advantages of the dry desulfurization process, such as simple process, less land occupation, no waste water generation, no need for chimney anti-corrosion treatment, small investment and by-products can be comprehensively utilized, etc., but also can achieve a desulfurization efficiency of up to more than 98% under very low calcium-sulfur ratio conditions.

[0004] A reverse cone ash hopper is arranged below the existing bag dust collector. The ash hopper plays a role in storing ash. The dust-containing flue gas with a higher speed enters the reverse cone ash hopper, and the stored ash is in a boiling state, generating secondary dust emission, which has an adverse impact on the dust removal operation.

[0005] The flue gas at the outlet of the desulfurization tower of the CFB semi-dry desulfurization and dust removal integrated process has the characteristics of "two highs and one low"; the dust concentration of the outlet flue gas is high, up to 800 - 1200g / Nm 3, this is because a large amount of circulating ash needs to be transported back to the absorption tower from the external return chute to maintain a high-density bed layer inside the tower during operation, resulting in a large amount of circulating ash; the high humidity of the outlet flue gas is due to the need to spray water into the absorption tower during operation to promote the reaction between hydrated lime and SO2 and keep hydrated lime and SO2 in the best reaction state; the low temperature of the outlet flue gas is because during operation, the desulfurization rate of the system increases with the increase of the water spray amount, and generally the outlet flue gas temperature is controlled above 15°C - 20°C of the flue gas dew point; therefore, for such harsh and severe flue gas conditions, more stringent requirements are imposed on the subsequent bag filter. A high dust concentration is likely to wear the filter bags and reduce their service life. High humidity and low temperature are likely to cause the filter bags to be clogged, blocked, and dew-condensed, and are also not conducive to the dust cleaning of the bag filter. After the above problems occur, it is easy to cause the dust to exceed the standard, bringing incalculable losses to the enterprise. Utility Model Content

[0006] To solve the deficiencies of the prior art, the purpose of the present utility model is to provide a new bag dust removal system for a desulfurization tower, which solves at least one of the above problems.

[0007] To achieve the above purpose, the technical solution of the present utility model is as follows:

[0008] A new bag dust removal system for a desulfurization tower, comprising: a desulfurization tower and a bag filter.

[0009] The flue gas outlet of the desulfurization tower is connected to the flue gas inlet of the bag filter. A conical ash hopper is arranged below the bag filter, and the conical ash hopper is connected to an ash hopper fluidization tank below.

[0010] In the present utility model, a conical ash hopper is arranged below the bag filter, and the conical ash hopper is connected to the ash hopper fluidization tank below. No ash is stored in the conical ash hopper. The flue gas passes through the desulfurization bag filter for gas-solid separation. The collected desulfurization ash flows through the ash hopper and is directly discharged into the ash hopper fluidization tank, preventing the flue gas from causing secondary entrainment and dusting through the flue in the bag filter, resulting in wear at the bottom of the filter bag and reducing the service life of the filter bag.

[0011] In some embodiments, a pre-settling chamber is connected in front of the bag filter. A flow guiding structure is arranged in the middle of the pre-settling chamber. The pre-settling chamber and the bag filter are separated by a side wall. An internal flue gas inlet is arranged below the side wall to connect the pre-settling chamber and the bag filter. A gas outlet is also arranged on the bag filter to communicate with the outside. The flue gas in the desulfurization tower passes through the pre-settling chamber to remove large particle dust (i.e., desulfurization ash) and equalize the flow, enters the filtering chamber through the internal flue gas inlet, and is discharged after dust removal in the filtering chamber.

[0012] In some embodiments, a return air chute is provided below the ash hopper fluidization tank, and the ash hopper fluidization tank is connected to the desulfurization tower through the return air chute. The return air chute sends the dust (i.e., desulfurized ash) collected by the ash hopper fluidization tank into the desulfurization tower for secondary utilization.

[0013] In some embodiments, an inverted cone ash hopper is also provided below the pre-settlement chamber, and the lower part of the inverted cone ash hopper is connected to the ash hopper fluidization tank.

[0014] In some embodiments, a desulfurized ash feeding and discharging system is provided below the pre-settlement chamber, and the desulfurized ash feeding and discharging system is connected to the inverted cone ash hopper and the ash hopper fluidization tank. When the amount of desulfurized ash generated by the bag filter meets the requirement for building the bed of the desulfurization tower, the desulfurized ash feeding and discharging system collects the desulfurized ash settled in the pre-settlement chamber. When the amount of desulfurized ash generated by the bag filter is insufficient, the desulfurized ash feeding and discharging system replenishes desulfurized ash into the ash hopper fluidization tank.

[0015] In some embodiments, a desulfurized ash recycling and discharging system is provided below the ash hopper fluidization tank, and the desulfurized ash recycling and discharging system is connected to the ash hopper fluidization tank and the return air chute. When the desulfurized ash collected in the ash hopper fluidization tank is greater than the requirement for building the bed of the desulfurization tower, the desulfurized ash recycling and discharging system collects and stores the desulfurized ash. When the desulfurized ash collected in the ash hopper fluidization tank is less than the requirement for building the bed of the desulfurization tower, the desulfurized ash recycling and discharging system replenishes desulfurized ash into the return air chute.

[0016] In some embodiments, the desulfurization tower is a semi-dry desulfurization tower.

[0017] In some embodiments, both the desulfurized ash feeding and discharging system and the desulfurized ash recycling and discharging system are provided with ash conveying silo pumps for temporarily storing desulfurized ash.

[0018] In some embodiments, the bag filter is provided with a plurality of filter chambers, and an inverted cone ash hopper is provided below each filter chamber.

[0019] In some embodiments, heating devices are provided on the inverted cone ash hopper and the ash hopper fluidization tank to heat the desulfurized ash. By heating, the temperature of the desulfurized ash is stabilized, preventing the formation of material condensation and caking, and ensuring the fluidity of the desulfurized ash.

[0020] The beneficial effects of the present utility model are as follows:

[0021] 1. The bag dust removal system of the present utility model adopts a two-stage ash hopper design. The first stage uses an inverted cone ash hopper, and the second stage uses an ash hopper fluidization tank. The flue gas with high-concentration dust coming out of the desulfurization tower passes through the desulfurization bag filter for gas-solid separation. The collected desulfurized ash flows through the first-stage ash hopper and discharges into the second-stage self-balancing ash hopper fluidization tank. This prevents the desulfurized ash from being stored in the first-stage inverted cone ash hopper, and it is easy for the flue gas to cause secondary entrainment and dusting through the original flue in the bag filter, resulting in wear at the bottom of the filter bag and reducing the service life of the filter bag.

[0022] 2. A pre-settling chamber is arranged in front of the flue gas passage of the bag filter of the present utility model, and a flow guiding structure is arranged in the pre-settling chamber, that is, no bags and bag cages are installed inside the first exhaust chamber connected to the outlet flue of the desulfurization tower. By adding the flow guiding structure, on the one hand, the air flow can be distributed, and at the same time, the resistance loss caused by the change of the air flow direction can be reduced, and the passing distance of the dust is extended, so that the dust gradually settles under the action of gravity. For CFB desulfurization towers with an outlet dust mass concentration of 800-1200 g / Nm 3 above, it can reduce the dust removal load of the filter bags, prevent the wear of the filter bags and the shell due to too high flue gas dust concentration; on the other hand, for the flue gas at the outlet of the biomass boiler which also contains a large amount of sparks, most of the sparks can be intercepted; the stability and safety of the desulfurization and dust removal system are increased.

[0023] 3. The present utility model also sets up a desulfurization ash feeding and discharging system and a desulfurization ash recycling and discharging system; when it can collect desulfurization ash for storage or supplement desulfurization ash, the stability of the cooled desulfurization ash returned to the desulfurization tower is improved. It not only increases the service life of the filter bags of the bag filter, but also ensures the stability of the bed formation of the desulfurization system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specification drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model.

[0025] Figure 1 It is a schematic structural connection diagram of the bag dust removal system of the semi-dry desulfurization tower according to Embodiment 1 of the present utility model;

[0026] Wherein, 1. Semi-dry desulfurization tower, 2. Pre-settling chamber, 3. Bag filter, 4. Inverted cone ash hopper, 5. Ash hopper fluidization tank, 6. Desulfurization ash feeding and discharging system, 7. Desulfurization ash recycling and discharging system, 8. Return air chute, 9. Flow guiding structure, 10. Ash conveying silo pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Aiming at the problems that the dusty flue gas of the existing bag dust removal desulfurization tower enters the inverted cone ash hopper to generate secondary dust raising, or the flue gas dust concentration, humidity and temperature at the outlet of the desulfurization tower are high, which is easy to cause bag sticking, blockage and condensation of the bags, and is not conducive to the ash cleaning of the bag filter, etc., the present utility model proposes a new bag dust removal system for the desulfurization tower.

[0028] In order to enable those skilled in the art to more clearly understand the technical solution of the present utility model, the technical solution of the present utility model will be described in detail below with specific embodiments.

[0029] Please refer toFigure 1 , the present utility model discloses a novel bag dust removal system for a desulfurization tower, comprising: a desulfurization tower and a bag filter 3; the flue gas outlet of the desulfurization tower is connected to the flue gas inlet of the bag filter 3, a conical ash hopper 4 is arranged below the bag filter 3, and the conical ash hopper 4 is connected to an ash hopper fluidization tank 5 below.

[0030] In an alternative embodiment, the novel bag dust removal system for the desulfurization tower further comprises: a pre-settlement chamber 2, a desulfurized ash feeding and discharging system 6, a desulfurized ash recycling and discharging system 7, a return air chute 8, a flow guiding device 9, and a pneumatic ash conveying silo pump 10, and the desulfurization tower is configured as a semi-dry desulfurization tower 1.

[0031] In an alternative embodiment, the desulfurized ash collected by the pre-settlement chamber 2 and the bag filter 3 flows through the conical ash hopper 4 and the conical ash hopper 4 and the ash hopper fluidization tank 5. After the desulfurized ash separated by the pre-settlement chamber 2 and the bag filter 3 flows through the conical ash hopper 4, it enters the ash hopper fluidization tank 5. There is no ash stored in the conical ash hopper 4. Compared with the traditional method where the bag inlet is in the ash hopper for air intake, this embodiment avoids the secondary dust generation caused by the impact and storage of ash in the conical ash hopper of the bag, which has an adverse effect on the dust removal operation.

[0032] In an alternative embodiment, the flue gas outlet of the semi-dry desulfurization tower 1 is connected to the pre-settlement chamber 2. The pre-settlement chamber 2 is arranged in front of the bag filter 3. A flow guiding structure 9 is arranged inside the pre-settlement chamber 2. The pre-settlement chamber 2 and the bag filter 3 are separated by a side wall. An internal flue gas inlet is arranged below the side wall to connect the pre-settlement chamber 2 and the bag filter 3. A gas outlet is also arranged on the bag filter 3 to communicate with the outside. Among them, the structure of the bag filter is prior art.

[0033] After the dust-containing flue gas discharged from the semi-dry desulfurization tower 1 enters the pre-settlement chamber 2, it passes through the flow guiding structure 9. The arrangement of the pre-settlement chamber 2 and the flow guiding structure 9 reduces the flow velocity of the flue gas. An internal flue gas inlet is arranged below the side wall, and the flue gas enters the bag filter through the internal flue gas inlet. The high-speed dust-containing air flow reduces its speed and is evenly distributed throughout the interior of the filter chamber, passes through the filter bag at a very slow speed, the dust is intercepted on the surface of the filter bag, and the gas is discharged after being purified. The structure of the bag filter 3 is prior art.

[0034] The present utility model optimizes the flow field and extends the travel distance of the dust through the pre-settlement chamber 2, enabling the dust to gradually settle under the action of gravity. The dust removal efficiency of the pre-settlement chamber can be increased to 60%, greatly reducing the dust concentration. While protecting the filter bag, the dust emission compliance is more stable and reliable.

[0035] Preferably, the flow guiding structure 9 can be arranged as an inclined flow guiding plate. The main function of the flow guiding structure 9 is to distribute the air flow, make the air flow distribution uniform among the filter chambers of the bag dust removal, and at the same time reduce the resistance loss caused by the change of the flue gas flow direction.

[0036] In an alternative embodiment, a return air chute 8 is provided below the hopper fluidization tank 5. The hopper fluidization tank 5 is connected to the semi-dry desulfurization tower 1 through the return air chute 8. The return air chute 8 sends the dust (i.e., desulfurized ash) collected by the hopper fluidization tank 5 into the desulfurization tower for secondary utilization. Specifically, the desulfurized ash stored in the hopper fluidization chute 5 is respectively connected to the return air chute 8 and the external discharge ash chute of the desulfurized ash circulation and discharge system 7 through an air inflation cylinder. A flow regulating valve is provided on the return air chute 8 to control the amount of desulfurized ash, adjust the bed layer thickness in the desulfurization tower, and maintain normal fluidization inside; on the external discharge ash chute, by opening the electric shut-off valve, the excess ash is discharged to the ash silo through an ash conveying bin pump.

[0037] In an alternative embodiment, the hopper fluidization tank 5 is connected to the desulfurized ash circulation and discharge system 7, and the desulfurized ash circulation and discharge system 7 is also connected to the return air chute 8; most of the desulfurized ash collected by the desulfurized ash circulation and discharge system 7 is returned to the semi-dry desulfurization tower 1 through the return air chute 8, and a small part of the ash is discharged to the ash silo for treatment or utilization through the ash conveying bin pump 10. According to the actual collection amount of desulfurized ash in the hopper fluidization tank 5 and the bed building requirements of the desulfurization tower, desulfurized ash is supplemented or collected in the return air chute 8 to adjust the desulfurized ash circulation amount.

[0038] Specifically, the desulfurized ash circulation and discharge system 7 includes: an ash conveying bin pump 10, a flap valve, an air inflation cylinder, a collecting electric regulating valve, an external discharge electric switch valve, a feeding chute, a dust chute, etc. The ash conveying bin pump 10 is used to temporarily store desulfurized ash. The structure of the desulfurized ash circulation and discharge system 7 is an existing technology.

[0039] In an alternative embodiment, the inverted cone ash hopper 4 at the bottom of the pre-settling chamber 2 is connected to the desulfurized ash feeding and discharge system 6, and the desulfurized ash feeding and discharge system 6 is also connected to the hopper fluidization tank 5; according to the actual collection amount of desulfurized ash generated in the pre-settling chamber 2 and the bed building requirements of the desulfurization tower, desulfurized ash is supplemented or collected in the hopper fluidization tank 5 to adjust the desulfurized ash circulation amount. The structure of the desulfurized ash feeding and discharge system 6 is substantially the same as that of the desulfurized ash circulation and discharge system 7, and the ash conveying bin pump 10 is used to temporarily store desulfurized ash. The structure of the desulfurized ash feeding and discharge system 6 is an existing technology.

[0040] In an alternative embodiment, the bag filter 3 is provided with a plurality of filter chambers, and an inverted cone ash hopper 4 is provided below each filter chamber.

[0041] In an alternative embodiment, a heating device is provided on the inverted conical ash hopper 4 and the ash hopper fluidization tank 5 to heat the desulfurized ash. Thereby ensuring the temperature of the desulfurized ash, preventing material condensation and caking, and ensuring the fluidity of the ash. Specifically, the heating device can adopt a steam heating element, which is easy to control, has uniform heating, low energy consumption, good economy, a simple system, and small maintenance; at the same time, a thermal resistor is used for feedback; the heating device also includes a constant temperature control device to control the heating element so that the temperature in the inverted conical ash hopper 4 and the ash hopper fluidization tank 5 is always maintained at a set value.

[0042] In an alternative embodiment, an induced draft fan is also provided inside the bag filter 3. When the differential pressure of the bag filter 3 reaches a certain set value (constant pressure cleaning) or the interval between two pulses reaches a certain set value (timed cleaning), the pulse jet valve automatically opens, and compressed air is sprayed into the inner side of the filter bag, so that the dust accumulated on the surface of the filter bag is peeled off and falls into the ash hopper. This is the prior art.

[0043] In an alternative embodiment, each inverted conical ash hopper 4 is provided with an ash outlet controlled by a slide valve. The angle between the inclined wall of the ash hopper and the horizontal plane is ensured to be not less than 60°. The inner side of the intersection of adjacent walls is made into an arc shape with a fillet radius of 200 mm to ensure the free flow of dust. The wall thickness of the dust collector ash hopper is ≥6 mm, and the structural strength of the ash hopper is ensured. The inverted conical ash hopper 4 should be provided with facilities to prevent the ash flow in the ash hopper from sticking or arching. This is the prior art.

[0044] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A new bag dust removal system for a desulfurization tower, characterized in that: include: Desulfurization tower, bag filter; The flue gas outlet of the desulfurization tower is connected to the flue gas inlet of the bag-type dust collector. An inverted cone ash hopper is arranged below the bag-type dust collector, and an ash hopper fluidizing trough is connected below the inverted cone ash hopper.

2. The novel bag dust removal system for the desulfurization tower according to claim 1 is characterized in that: The front of the bag-type dust collector is connected to a pre-sedimentation chamber, a guide structure is arranged in the middle of the pre-sedimentation chamber, the pre-sedimentation chamber and the bag-type dust collector are separated by a side wall, an internal flue gas inlet is arranged below the side wall to connect the pre-sedimentation chamber with the bag-type dust collector, and a gas outlet is also arranged on the bag-type dust collector to connect with the outside.

3. The novel bag dust removal system for the desulfurization tower according to claim 1 is characterized in that: A return air chute is provided below the ash hopper fluidizing trough, and the ash hopper fluidizing trough is connected to the desulfurization tower through the return air chute.

4. The novel bag dust removal system for the desulfurization tower according to claim 2 is characterized in that: An inverted cone ash hopper is also arranged below the pre-sedimentation chamber, and the bottom of the inverted cone ash hopper is connected to the ash hopper fluidizing trough.

5. The novel bag dust removal system for the desulfurization tower according to claim 2 is characterized in that: A desulfurization ash feeding and discharge system is arranged below the pre-sedimentation chamber, and the desulfurization ash feeding and discharge system is connected with the inverted cone ash hopper and the ash hopper fluidization trough.

6. The novel bag dust removal system for the desulfurization tower according to claim 5, characterized in that: A desulfurization ash circulation and discharge system is arranged below the ash hopper fluidizing trough, and the desulfurization ash circulation and discharge system is connected with the ash hopper fluidizing trough and the return air chute.

7. The novel bag dust removal system for the desulfurization tower according to claim 6, characterized in that: Both the desulfurization ash feeding and discharge system and the desulfurization ash circulation and discharge system are equipped with ash silo pumps for temporary storage of desulfurization ash.

8. The novel bag dust removal system for a desulfurization tower according to claim 1, characterized in that: The bag dust collector is provided with multiple filter chambers, and an inverted cone ash hopper is provided under each filter chamber.

9. The novel bag dust removal system for a desulfurization tower according to claim 1, characterized in that: Heating devices are arranged on the inverted cone ash hopper and the ash hopper fluidizing trough to heat the desulfurization ash.

10. The novel bag dust removal system for a desulfurization tower according to claim 1, characterized in that: The desulfurization tower is a semi-dry desulfurization tower.

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