Flue gas system capable of preventing circulating pump from being abraded

Abstract

A flue gas system for preventing abrasion of a circulating pump belongs to the technical field of flue gas desulfurization and comprises an absorption tower, a slurry buffer assembly and a discharge pump, the absorption tower is used for absorbing sulfur dioxide in flue gas, and a spraying mechanism is arranged on the absorption tower; the slurry buffer assembly comprises a pipeline mixer and a material buffer, the pipeline mixer is provided with a first inlet, a second inlet and an outlet, the first inlet is connected with the liquid phase outlet of the absorption tower, the outlet is connected with the inlet of the material buffer, the second inlet is connected with a material storage tank, and the material storage tank is connected with the material buffer. A plurality of baffle plates vertical to the flow direction of the slurry are arranged in the material buffer; the discharging pump is connected with an outlet of the material buffer, the flowing direction of slurry in the material buffer is changed, impact force brought by the slurry is weakened, the slurry flowing in a turbulent flow mode is changed into slurry flowing in a laminar flow mode, impact of the slurry on the discharging pump is avoided, and blades and other structures of the discharging pump are protected.

Description

Technical Field

[0001] The present application belongs to the technical field of flue gas desulfurization, and in particular relates to a flue gas system for preventing a circulation pump from wearing out. Background Art

[0002] Currently, the wet limestone-gypsum desulfurization process is the dominant flue gas desulfurization process in my country's thermal power plants. The absorption tower is the core equipment in the wet desulfurization unit. Limestone slurry countercurrently washes the flue gas within the absorption tower. Limestone slurry droplets sprayed through atomizing nozzles react with sulfur dioxide in the flue gas to produce soluble calcium sulfite and calcium bisulfite, which flow into the slurry tank as small particles. An oxidation fan sprays oxidizing air into the slurry tank. The agitator, acting as a stirrer, almost completely oxidizes the calcium sulfite and calcium bisulfite to form gypsum crystals. The slurry is discharged by a gypsum discharge pump and sent to a gypsum cyclone for concentration and particle classification to finally obtain gypsum; or the slurry is extracted from the bottom of the absorption tower by a pump and sent upward to the spray layer to provide working pressure for the atomizing nozzle so that the slurry is atomized as much as possible after passing through the nozzle, so that the small droplets can fully contact with the ascending flue gas and the sulfur dioxide in the flue gas can be completely absorbed. The desulfurization pump is an important component to ensure the normal operation of the desulfurization system. It is also a key equipment for the desulfurization system of thermal power plants and chemical plants to ensure environmental protection indicators.

[0003] For example, the Chinese invention patent with publication number "CN201820257899.9" discloses a desulfurization pump and a wet flue gas desulfurization system repaired with composite ceramics. The desulfurization pump repaired with composite ceramics includes a pump head assembly and a transmission assembly connected to the pump head assembly; the pump head assembly includes a pump body, a first pump cover and a second pump cover respectively connected to the two sides of the pump body, and an impeller arranged inside the pump body; the transmission assembly includes a pump shaft, a first mechanical seal device, a bearing box and a bearing bracket; a guard plate is provided on the side of the first pump cover close to the second pump cover, and the surface of the guard plate is coated with a composite ceramic coating, which solves the technical problem in the prior art that the desulfurization pump is easily subject to acid corrosion, wear and cavitation of the slurry, causing the desulfurization pump to be damaged. By coating the composite ceramic coating on the surface of the guard plate, the acid corrosion, wear and cavitation of the slurry on the guard plate are effectively reduced, so that the first pump casing will not be damaged, thereby improving the service life of the desulfurization pump.

[0004] However, although the above solution protects the blades in the pump from corrosion, it ignores the impact force of the slurry on the pump. Summary of the Invention

[0005] In view of this, it is necessary to provide a solution to the problem that the pump is damaged due to the impact force of the slurry.

[0006] The solution to the technical problem described in this application is:

[0007] A flue gas system for preventing a circulation pump from wearing out, comprising

[0008] An absorption tower, the absorption tower is used to absorb sulfur dioxide in the flue gas, and the absorption tower is provided with a spray mechanism;

[0009] A slurry buffer assembly, comprising a pipeline mixer and a material buffer, wherein the pipeline mixer is provided with a first inlet, a second inlet, and an outlet, wherein the first inlet is connected to the liquid phase outlet of the absorption tower, the outlet is connected to the inlet of the material buffer, the second inlet is connected to a material storage tank, and the material buffer is provided with a plurality of baffles perpendicular to the slurry flow direction; and

[0010] A discharge pump, wherein the inlet of the discharge pump is connected to the outlet of the material buffer.

[0011] Preferably, the pipeline mixer is a three-way mixer.

[0012] Preferably, a flow control valve is provided between the second inlet and the material storage tank.

[0013] Preferably, one end of the baffle plate is connected to the bottom of the material buffer, and the height of the baffle plate is lower than the height of the side wall of the material buffer and higher than the distance between the inlet of the material buffer and the bottom of the material buffer.

[0014] Preferably, a material outlet is provided on the material buffer and is located below the material buffer.

[0015] Preferably, a plurality of baffles are provided on the top surface of the material buffer, the baffles are spaced apart from the material baffle plates, and the baffles partially overlap with the material baffle plates.

[0016] Preferably, the material buffer is a bucket-shaped expander.

[0017] Preferably, a reflux pipe is further included, one end of which is connected to the outlet of the discharge pump, and the other end is connected to the spray mechanism.

[0018] Preferably, it further comprises a semi-finished product collection box, which is connected to the outlet of the discharge pump.

[0019] Beneficial effect: The present application discloses a flue gas system for preventing wear of a circulating pump, comprising an absorption tower, a slurry buffer assembly and a discharge pump. The slurry changes its flow direction in the material buffer, weakens the impact force brought by the slurry, and changes the slurry flowing in a turbulent manner into a slurry flowing in a laminar manner. Finally, the slurry enters the discharge pump, avoiding the impact of the slurry on the discharge pump and protecting the blades and other structures of the discharge pump; at the same time, the new limestone or carbide slag slurry and the slurry discharged from the liquid phase outlet of the absorption tower can be better mixed in the pipeline mixer to form a mixed slurry, ensuring the uniformity of the slurry and uniformly distributing calcium ions. When the mixed slurry flows back into the absorption tower, it can better absorb the SO2 in the absorption tower and convert the calcium sulfite in the mixed slurry into calcium sulfate, thereby improving the purity of the gypsum. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram of the device of the flue gas system for preventing the wear of the circulation pump in this application.

[0021] In the figure: absorption tower 10, spray mechanism 101, slurry buffer assembly 20, pipeline mixer 201, first inlet 2011, second inlet 2012, outlet 2013, flow control valve 2014, material buffer 202, material baffle 2021, material outlet 2022, baffle 2023, discharge pump 30, reflux pipe 40, semi-finished product collection box 50. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction to the drawings required for use in the embodiments will be given below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Please see Figure 1 A flue gas system for preventing wear of a circulating pump includes an absorption tower 10, a slurry buffer assembly 20 and a discharge pump 30. The absorption tower 10 is used to absorb sulfur dioxide in the flue gas, and the absorption tower 10 is provided with a spray mechanism 101; the slurry buffer assembly 20 includes a pipeline mixer 201 and a material buffer 202, the pipeline mixer 201 is provided with a first inlet 2011, a second inlet 2012 and an outlet 2013, the first inlet 2011 is connected to the liquid phase outlet of the absorption tower 10, the outlet 2013 is connected to the inlet of the material buffer 202, the second inlet 2012 is connected to a material storage tank, and the material buffer 202 is provided with a plurality of baffles 2021 perpendicular to the slurry flow direction; the discharge pump 30 is connected to the outlet of the material buffer 202.

[0024] The absorption tower 10 is constructed of carbon steel plate lined with glass flakes. Several layers of spray mechanisms 101 are arranged within the absorption tower 10, and a gas phase region and a liquid phase region are provided within the absorption tower 10. The spray mechanisms 101, gas phase region, and liquid phase region are sequentially arranged downward. When flue gas enters the center of the absorption tower 10, i.e., the gas phase region, the spray mechanism 101 converts the slurry into a mist and sprays it out. The misted slurry reacts with the SO2 within the absorption tower 10 to produce calcium sulfate, which is then discharged from the liquid phase outlet of the absorption tower 10. The pipeline mixer 201 is a mixer without any mechanical moving parts that achieves uniform mixing of fluids flowing through the pipeline through the action of a certain component or mixing element. Commonly used pipeline mixers 201 in industry include static baffle, orifice plate, and three-way mixers. The material buffer 202 is a storage device or buffer.

[0025] Working process: After the slurry at the bottom of the absorption tower 10 is discharged from the liquid phase outlet of the absorption tower 10, it enters the pipeline mixer 201. At this time, limestone or carbide slag slurry is introduced into the pipeline mixer 201 through the second inlet 2012 to increase the concentration of calcium ions in the mixed slurry and convert the calcium sulfite in the slurry into calcium sulfate, thereby improving the purity of the gypsum; then the mixed slurry enters the material buffer 202 from the outlet 2013. The material buffer 202 changes the moving direction of the slurry under the action of the baffle plate 2021. The slurry originally flows in the same direction. Under the action of the baffle plate 2021, the slurry is dispersed and flows. Due to the expansion of the space of the material buffer 202, the slurry first fills the material buffer 202 in the material buffer 202, and then flows out of the material buffer 202, reducing the impact force brought by the slurry during the flow process.

[0026] Beneficial effect: the slurry changes its flow direction in the material buffer 202, weakens the impact force brought by the slurry, and changes the slurry flowing in a turbulent manner into a slurry flowing in a laminar manner. Finally, the slurry enters the discharge pump 30, avoiding the impact of the slurry on the discharge pump 30 and protecting the blades and other structures of the discharge pump 30; at the same time, the new limestone or carbide slag slurry and the slurry discharged from the liquid phase outlet of the absorption tower 10 can be better mixed in the pipeline mixer 201 to form a mixed slurry, ensuring the uniformity of the slurry and uniformly distributing the calcium ions. When the mixed slurry flows back to the absorption tower 10, it can better absorb the SO2 in the absorption tower 10 and convert the calcium sulfite in the mixed slurry into calcium sulfate, thereby improving the purity of the gypsum.

[0027] At the same time, the mixed slurry enters the material buffer 202 from the outlet 2013. The material buffer 202 changes the moving direction of the slurry under the action of the baffle plate 2021. The slurry originally flows in the same direction. Under the action of the baffle plate 2021, the slurry is dispersed and flows. Since the space of the material buffer 202 is expanded, the slurry first fills the material buffer 202 in the material buffer 202, and then flows out of the material buffer 202, thereby reducing the impact force brought by the slurry during the flow process; if the mixed slurry enters the inlet of the material buffer 202 in a horizontal state, under the action of the baffle plate 2021, the mixed slurry flows into the internal cavity of the material buffer 202 in a vertical or inclined flow direction, thereby avoiding the mixed slurry from rushing directly into the discharge pump 30 in one direction, thereby reducing the impact force of the mixed slurry on the discharge pump 30.

[0028] Specifically, the pipeline mixer 201 is a three-way mixer.

[0029] A three-way mixer achieves fluid mixing through the interconnection and cross-flow of three channels. This mixer is suitable for larger flow rates and a wider mixing range, which is exactly what is needed when slurries contain particulate matter. Furthermore, the three-way mixer can better mix the slurry evenly, eliminating the need for additional slurry mixing devices because the slurry is mixed evenly as it passes through the three-way mixer.

[0030] In a preferred embodiment, a flow control valve 2014 is provided between the second inlet 2012 and the material storage tank.

[0031] The amount of limestone or carbide slag slurry added depends on the concentration of SO2 in the absorption tower 10. At this time, the flow control valve 2014 is set to select the amount of limestone or carbide slag slurry added according to the concentration of SO2 in the absorption tower 10.

[0032] In a preferred embodiment, one end of the baffle plate 2021 is connected to the bottom of the material buffer 202, and the height of the baffle plate 2021 is lower than the side wall height of the material buffer 202 and higher than the distance between the inlet of the material buffer 202 and the bottom of the material buffer 202.

[0033] When the baffle plate 2021 is set, it must be lower than the side wall height of the material buffer 202, and there must be a slurry flow channel between the baffle plate 2021 and the side wall of the material buffer 202. If the baffle plate 2021 is at the same height as the side wall of the material buffer 202, the slurry cannot pass through the material buffer 202, and when the baffle plate 2021 is set, the height of the baffle plate 2021 must be higher than the inlet height of the material buffer 202. The advantage of this is that the material flows in a direction parallel to the bottom surface of the material buffer 202. When the slurry flows into the material buffer 202, if the height of the baffle plate 2021 is lower than the inlet height of the material buffer 202, the slurry will rush to the outlet of the material buffer 202 in the flow direction of entering the inlet of the material buffer 202, and will not be able to reduce the impact force of the slurry. On the contrary, if the height of the baffle plate 2021 is higher than the inlet height of the material buffer 202, after the slurry contacts the baffle plate 2021, the slurry will change from the same flow direction to multiple flow directions, thereby achieving the purpose of reducing the impact force of the slurry.

[0034] In a preferred embodiment, a material outlet 2022 is provided on the material buffer 202 and is located below the material buffer 202 .

[0035] Since some of the substances in the slurry will settle in the material buffer 202 after passing through the material buffer 202, in order to remove the materials settled in the material buffer 202, the material outlet 2022 is set at the bottom of the material buffer 202. When there is sediment in the material buffer 202, the sediment in the material buffer 202 is removed from the material outlet 2022.

[0036] In a preferred embodiment, a plurality of baffles 2023 are provided on the top surface of the material buffer 202 , the baffles 2023 are spaced apart from the material baffles 2021 , and the baffles 2023 and the material baffles 2021 partially overlap.

[0037] In order to better reduce the impact force of the slurry, a number of baffles 2023 are set at the top of the material buffer 202. The baffles 2023 and the baffle plates 2021 are spaced apart in the horizontal direction and partially overlap in the height direction to form an S-shaped flow path. The slurry flows in this path and will decelerate first after contacting the baffles 2023, and decelerate a second time after contacting the baffle plates 2021, thereby better reducing the impact force of the slurry.

[0038] Furthermore, the material buffer 202 is a bucket-shaped expander.

[0039] Since the internal cavity of the bucket-shaped expander is larger than the internal cavity of the pipeline mixer 201, the slurry instantly enters a larger cavity. At this time, most of the slurry will reduce its flow rate and flow to the bottom of the bucket-shaped expander under the action of gravity. Then, it flows into the discharge pump 30 from the outlet of the bucket-shaped expander, thereby achieving the purpose of reducing the impact force of the mixed slurry.

[0040] In one embodiment, a reflux pipe 40 is further included, one end of which is connected to the outlet of the discharge pump 30 , and the other end of which is connected to the spray structure.

[0041] The slurry is discharged from the liquid phase outlet of the absorption tower 10, and a part of the slurry returns to the spraying mechanism 101. At this time, in order to improve the utilization rate of the slurry, limestone or carbide slag slurry is added to the slurry discharged from the liquid phase outlet of the absorption tower 10 to increase the concentration of calcium ions in the slurry and better absorb the SO2 in the absorption tower 10.

[0042] Specifically, it further includes a semi-finished product collection box 50 , which is connected to the outlet of the discharge pump 30 .

[0043] The slurry is discharged from the liquid phase outlet of the absorption tower 10, and a portion of the slurry is used as a raw material for preparing gypsum. At this time, this portion of the slurry will be discharged into the semi-finished product collection box 50 to facilitate the subsequent preparation of gypsum.

[0044] The above disclosure is only a preferred embodiment of the present application, and it is certainly not intended to limit the scope of the rights of the present application. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made in accordance with the claims of the present application are still within the scope of the present application.

Claims

1. A flue gas system for preventing circulation pump wear, characterized in that: include An absorption tower, the absorption tower is used to absorb sulfur dioxide in the flue gas, and the absorption tower is provided with a spray mechanism; A slurry buffer assembly, comprising a pipeline mixer and a material buffer, wherein the pipeline mixer is provided with a first inlet, a second inlet, and an outlet, wherein the first inlet is connected to the liquid phase outlet of the absorption tower, the outlet is connected to the inlet of the material buffer, the second inlet is connected to a material storage tank, and the material buffer is provided with a plurality of baffles perpendicular to the slurry flow direction; and A discharge pump, wherein the inlet of the discharge pump is connected to the outlet of the material buffer.

2. The flue gas system for preventing circulation pump wear according to claim 1, characterized in that: The pipeline mixer is a three-way mixer.

3. The flue gas system for preventing circulation pump wear according to claim 1, characterized in that: A flow control valve is provided between the second inlet and the material storage tank.

4. The flue gas system for preventing circulation pump wear as claimed in claim 1, characterized in that: One end of the baffle plate is connected to the bottom of the material buffer. The height of the baffle plate is lower than the side wall height of the material buffer and higher than the distance between the inlet of the material buffer and the bottom of the material buffer.

5. The flue gas system for preventing circulation pump wear as claimed in claim 1, characterized in that: A material outlet is provided on the material buffer and is located below the material buffer.

6. The flue gas system for preventing circulation pump wear as claimed in claim 4, characterized in that: A plurality of baffles are provided on the top surface of the material buffer, the baffles are spaced apart from the material baffle plates, and the baffles partially overlap with the material baffle plates.

7. The flue gas system for preventing circulation pump wear as claimed in claim 1, characterized in that: The material buffer is a bucket-shaped expander.

8. The flue gas system for preventing circulation pump wear as claimed in claim 1, characterized in that: It also includes a reflux pipe, one end of which is connected to the outlet of the discharge pump, and the other end is connected to the spray mechanism.

9. The flue gas system for preventing circulation pump wear as claimed in claim 1, characterized in that: It also includes a semi-finished product collection box, which is connected to the outlet of the discharge pump.

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