Gypsum rain control device and system

Abstract

The invention discloses a gypsum rain control device and system. The gypsum rain control device comprises a first-stage rim, a second-stage rim, a third-stage rim, a fourth-stage rim, a fifth-stage rim, a first-stage internal rotation blade, a first-stage external rotation blade, a second-stage internal rotation blade and a second-stage external rotation blade. The water removal device is arranged at the upper part of an inner barrel of a chimney subjected to wet desulphurization. An arc-shaped bottom plate and a drainage port are arranged on the lower portion of the chimney inner cylinder, and smoke and water intercepted by the water removal device are discharged out of a smoke system through the drainage port and a drainage pipe. By means of multi-layer flue gas diversion, the mechanical collision coagulation effect of liquid water drops in strong flue gas is achieved, and therefore fine and discrete liquid drops in the flue gas are gathered and removed. The system can effectively solve the problem of rainfall of wet chimneys in alpine regions and high-humidity regions.

Description

Technical Field

[0001] The invention belongs to the field of gypsum rain prevention and control, and specifically relates to a device and a system for intercepting liquid water entrained in chimney flue gas by utilizing the mechanical condensation principle. Background Art

[0002] "Gypsum rain" / "chimney rain" is a common associated flue gas "pollution" problem in the wet flue gas desulfurization process. It refers to the fact that under special circumstances, when the flue gas after wet flue gas desulfurization is discharged through the chimney, "rainfall" will occur near the chimney. Some rainfall mixed with wet flue gas desulfurization slurry is called "gypsum rain", and some rainfall without slurry is called "chimney rain". It contains two meanings: "gypsum" and "rain". "Gypsum" refers to gypsum slurry; "rainfall" refers to condensate droplets formed by saturated water in clean flue gas.

[0003] "Gypsum" is formed by the gypsum slurry entrained in the flue gas falling to the ground with the flue gas discharge. The gypsum slurry in the clean flue gas of the desulfurization device mainly comes from the fine droplets atomized by the nozzle of the spray layer of the absorption tower. The diameter of the droplets of gypsum slurry after atomization by the nozzle is generally 920 μm, and a small amount of about 15 μm will be produced after collision. After passing through the demister, 99.99% of the droplets not less than 22 μm will generally be removed, and 50% of the droplets of 15-22 μm can also be removed. The droplets below 15 μm cannot be intercepted, so it is inevitable that there is a certain amount of gypsum slurry in the clean flue gas. However, if the flow rate of the flue gas at the demister exceeds the design value, the effect of the demister will be greatly reduced or even fail. The demister will also have a secondary carryover phenomenon under high-speed flue gas, and a large amount of gypsum slurry will be brought into the chimney with the flue gas, forming a clean flue gas slurry phenomenon. The formation of "gypsum" is related to many factors, mainly including the demisting effect of the demister, the design of the absorption tower, and its operation.

[0004] "Rain" is the condensate in the clean flue gas. The direct reason for its formation is that in addition to saturated water vapor, the flue gas also carries droplets that have not been removed by the demister. The moisture in the flue gas is mainly composed of droplets escaping from the demister. The indirect reason for its formation is the adiabatic expansion of saturated flue gas and the condensate formed by contact with the flue and chimney inner wall. When saturated wet flue gas rises in the chimney, the flue gas pressure decreases. After adiabatic expansion, the flue gas is cooled and forms very fine droplets (diameter <1 μm). Adiabatic expansion produces the largest number of droplets in the chimney. Inside the chimney, due to the effect of inertia, the larger water droplets entrained by the flue gas hit the flue and chimney walls, combine with the condensate on the wall, and are brought back into the flue gas under the influence of airflow. The diameter of these re-entrained droplets is usually 100-500 μm, and their number depends on the characteristics of the wall and the flue gas flow rate. Rough walls and higher flue gas flow rates will increase the amount of entrained droplets [3]. Another reason for the formation of "rain" is the influence of environmental factors. Usually, low ambient temperature and low air pressure will cause the appearance of "rain". The temperature of flue gas after desulfurization is usually around 50 ℃. Compared with the direct discharge of the original flue gas without desulfurization, the clean flue gas after desulfurization is relatively poor in lifting height and diffusion capacity. Therefore, when the flue gas after desulfurization is discharged from the chimney, due to the large difference between the flue gas temperature and the ambient temperature, the flue gas has no time to diffuse, and the saturated water in the flue gas becomes supersaturated when it is cooled, and finally becomes condensed liquid and falls to the ground to form "rain". The greater the difference between the flue gas discharge temperature and the ambient temperature, the easier it is to form "rain".

[0005] Whether it is "gypsum" or "rain", it will fall to the ground in the low temperature environment in winter and the low pressure and high humidity environment in the coastal area, bringing adverse effects to the production and life near the chimney. The treatment of gypsum rain and chimney rain is an issue that the environmental protection industry should pay attention to and properly solve. Summary of the invention

[0006] In order to solve the gypsum rain / chimney rain problem caused by the wet flue gas desulfurization system, and solve and reduce the impact of the "water falling" phenomenon associated with the chimney on the surrounding production and life, the present invention provides a chimney water removal device installed inside the chimney. Through the principle of multi-layer mechanical diversion, the flue gas in the chimney is layered and guided to collide, so that the droplets in the chimney that cannot fall naturally are condensed and agglomerated to form larger droplets, which fall from the inside of the chimney under the action of their own weight. In addition, the present invention also specially designs a hydrophobic device, which can collect the liquid intercepted by the water removal device and remove it from the outside of the chimney.

[0007] The present invention provides a gypsum rain prevention and control device and system, which is characterized in that it includes a primary wheel rim, a secondary wheel rim, a tertiary wheel rim, a fourth wheel rim, a fifth wheel rim, a primary inward rotating blade, a primary outward rotating blade, a secondary inward rotating blade, a secondary outward rotating blade, and a center blind plate. The above structures together constitute a water removal device unit.

[0008] Furthermore, the water removal device is installed in the wet desulfurization absorption tower and the chimney at the rear of the clean flue.

[0009] Furthermore, the water removal device is installed at the upper part of the chimney inner tube, and the lower part of the chimney inner tube is equipped with an arc bottom plate, a drain port, and a water pipe to discharge the intercepted gypsum rain out of the system.

[0010] Furthermore, the dewatering device is a multi-layer circular fixed impeller structure with a central blind plate, wherein the diameters of the first-stage rim, the second-stage rim, the third-stage rim, the fourth-stage rim and the fifth-stage rim are gradually reduced.

[0011] Further, the first-stage inner rotating blade is a clockwise, circumferentially uniform, centrally symmetrical n-stage blade with an α° inclination angle, wherein 1°<α<90°, n≥3. It is installed between the first-stage rim and the second-stage rim, and the inner and outer sides of the blade are fully welded to the rim.

[0012] Furthermore, the first-stage outward rotating blade is a counterclockwise, circumferentially evenly distributed, centrally symmetrical N-stage blade with a β° inclination angle, wherein 1°<β<90°, N≥3. It is installed between the second-stage rim and the third-stage rim, and the inner and outer sides of the blade are fully welded to the rim.

[0013] Furthermore, the secondary inward rotating blade is a clockwise, circumferentially evenly distributed, centrally symmetrical n-stage blade with an α° inclination angle, wherein 1°<α<90°, n≥3. It is installed between the third-stage rim and the fourth-stage rim, and the inner and outer sides of the blade are fully welded to the rim.

[0014] Further, the secondary external rotating blade is a counterclockwise, circumferentially evenly distributed, centrally symmetrical N-stage blade with a β° inclination angle, wherein 1°<β<90°, N≥3. It is installed between the fourth-stage rim and the fifth-stage rim, and the inner and outer sides of the blade are fully welded to the rim.

[0015] The beneficial effects of the present invention are: 1. Droplet graded diversion, collision and coagulation. The specially designed multi-stage impeller structure of the present invention gradedly diverts the flue gas at the chimney outlet, and the directions of the two adjacent stages of flue gas diversion are different, resulting in mechanical collision when the subsequent flue gas converges. During the collision process, the droplets mixed in the flue gas will break through the surface tension of the liquid film and coagulate into large droplets with larger particle size and mass. The large droplets will fall naturally under the action of their own weight to avoid the phenomenon that after the small droplets are discharged from the chimney with the flue gas, they will continue to coagulate and grow due to insufficient supporting force due to the sudden drop in flow velocity and the decrease in temperature, and then fall to the vicinity of the chimney.

[0016] 2. The impeller wall intercepts condensation and crushing. In the process of guiding the flue gas, the porosity of the present invention is greater than 95% for each spatial section of the flue gas passing through the dehydration device, and the sacrificed porosity is only the sum of the impeller thickness and the rim thickness in each section. However, in the top view, the equipment covers the flue gas comprehensively, that is, all flue gases will be diverted when passing through the dehydration device. The advantage is that when passing through the impeller, the droplets mixed in the flue gas are more likely to contact and collide with the blades due to their higher density than the flue gas and greater inertial force. In addition, because the flue gas flow rate in the chimney design is very fast, usually exceeding 15m / s, at such a flow rate, the droplets contact and collide with the impeller, which can easily break through the surface tension of the droplet film, and the droplets are broken and condensed, and are forcibly gathered into a flow by the impeller. The other part of the broken droplets are more easily carried away by the wind or evaporated naturally after the flue gas is discharged from the chimney, and will not fall into chimney rain.

[0017] 3. Simple design, easy installation and maintenance-free. In terms of core structure, this gypsum rain prevention device is only composed of rough circular wheels and blades. In order to control the resistance, the gaps between different structural blocks are large, which is not easy to hide dirt. In addition, the relative humidity of the flue gas after wet desulfurization is 100%, and it is rich in liquid water. In addition, the chimney flue gas has a fast flow rate, and the flue gas rich in liquid water flushes the structure for a long time, and there is no flushing maintenance work. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the monomer structure of the gypsum rain prevention and control device of the present invention; Figure 2 It is a schematic diagram of the installation position and the collection structure of intercepted water of the present invention;

[0019] DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0021] like Figure 1As shown, an embodiment of the present invention provides a gypsum rain prevention and control device and system, including a primary rim 1, a secondary rim 2, a tertiary rim 3, a quaternary rim 4, a quintuple rim 5, a primary inward rotating blade 6, a primary outward rotating blade 7, a secondary inward rotating blade 8, a secondary outward rotating blade 9, and a center blind plate 10, and the above structures together constitute a dewatering device 11 unit. The dewatering device 11 is a multi-layer circular fixed impeller-shaped structure, and a center blind plate 10 is provided. Among them, the primary rim 1, the secondary rim 2, the tertiary rim 3, the quaternary rim 4, and the quintuple rim 5 are of the same height, all of which are 500mm~1000mm, and the diameter is gradually reduced. The primary inward rotating blade 6 is a clockwise, circumferentially evenly distributed, centrally symmetrical multi-stage blade with a certain inclination angle (usually designed to be 45°~60°) (the number of blades is usually designed to be 12~30). It is installed between the primary rim 1 and the secondary rim 2, and the inner and outer sides of the blades are fully welded to the rim. The first-stage external rotating blade 7 is a counterclockwise, circumferentially evenly distributed, centrally symmetrical multi-stage blade with a certain tilt angle (usually designed to be 45°~60°) (the number of blades is usually designed to be 12~30). It is installed between the second-stage rim 2 and the third-stage rim 3, and the inner and outer sides of the blades are fully welded to the rim. The second-stage internal rotating blade 8 is a clockwise, circumferentially evenly distributed, centrally symmetrical multi-stage blade with a certain tilt angle (usually designed to be 45°~60°) (the number of blades is usually designed to be 12~30). It is installed between the third-stage rim 3 and the fourth-stage rim 4, and the inner and outer sides of the blades are fully welded to the rim. The second-stage external rotating blade 9 is a counterclockwise, circumferentially evenly distributed, centrally symmetrical multi-stage blade with a certain tilt angle (usually designed to be 45°~60°) (the number of blades is usually designed to be 12~30). It is installed between the fourth-stage rim 4 and the fifth-stage rim 5, and the inner and outer sides of the blades are fully welded to the rim.

[0022] like Figure 2 As shown, the water removal device 11 is installed in the chimney 14 at the rear of the wet flue gas absorption tower 12 and the clean flue 13. The water removal device 11 is installed on the upper part of the chimney inner tube 15, and the distance from the chimney outlet is generally designed to be 10m~15m, because the flue gas in the chimney has been fully cooled and is closer to the temperature of the chimney outlet, and the condensed water droplets in the flue gas are more abundant. At the same time, the lower part of the chimney inner tube 15 is equipped with an arc bottom plate 16, a drain port 17, and a water pipe 18. The water-containing part of the flue gas intercepted by the water removal device 11 naturally falls into the arc bottom plate 16, and a part flows along the wall of the chimney inner tube 15 to the arc bottom plate, and finally discharged from the system from the drain port 17 and the drain pipe 18. Example

[0023] The gypsum rain prevention and control device is installed in the chimney inner tube 15 behind the limestone-gypsum wet desulfurization absorption tower 12 of the 300MW coal-fired power plant, wherein the water removal device 11 has the same diameter as the chimney inner tube, both of which are 5m. The water removal device is 10m high from the top of the chimney inner tube, and the water removal device 11 body is 500mm high. It is divided into five rims, and the diameter of each rim gradually decreases, wherein the first-level rim 1 has a diameter of 5m, the second-level rim 2 has a diameter of 4m, the third-level rim has a diameter of 3m, the fourth-level rim has a diameter of 2m, and the fifth-level rim has a diameter of 1m. There are 24 first-level inward rotating blades 6, first-level outward rotating blades 7, second-level inward rotating blades 8, and second-level outward rotating blades 9 between the five-level rims, and the angles with the vertical direction are all 45°, and they are evenly fixed between the rims in a central symmetric manner. Among them, the first-level inward rotating blades 6 and the second-level inward rotating blades 8 are arranged clockwise, and the first-level outward rotating blades 7 and the second-level outward rotating blades 9 are arranged counterclockwise.

[0024] In this embodiment, the flue gas at the outlet of the wet flue gas absorption tower 12 is saturated flue gas and is sandwiched with a small amount of gypsum slurry. The flue gas enters the chimney 14 through the clean flue 13. It flows upward in the chimney inner tube 15 and passes through the dewatering device 11. When passing through the dewatering device 11, the flue gas is cut into four flue gas flow layers with diameters from large to small by the first-level wheel rim 1, the second-level wheel rim 2, the third-level wheel rim 3, the fourth-level wheel rim 4, and the fifth-level wheel rim 5 in annular layers. These four flue gas flow layers pass through four impeller groups composed of 24 first-level inner rotating blades 6, 24 first-level outer rotating blades 7, 24 second-level inner rotating blades 8, and 24 second-level outer rotating blades 9. At the same time, some of the droplets entrained in the flue gas will directly collide with the blades, be condensed and intercepted, converge and become larger, and then flow into the arc bottom plate 16 under the action of gravity. The flue gas that is not intercepted by the blades continues to ascend, and the flue gas rotates clockwise and counterclockwise at intervals when passing through the impeller group. The flue gas containing liquid droplets rotating in different directions will diffuse naturally after passing through the main structure of the water removal device 11. During diffusion, the two adjacent layers of flue gas will collide due to the inconsistent rotation directions. The collision process causes the droplets contained in the flue gas to break through the surface tension and condense and agglomerate, and finally fall to the arc bottom plate 16 and discharge from the system through the drain port 17 and the drain pipe 18.

[0025] In the description of the present invention, it is necessary to understand that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "inside", "outside", "peripheral", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred system or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0027] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gypsum rain prevention device and system, characterized in that: The invention comprises a first-stage wheel rim (1), a second-stage wheel rim (2), a third-stage wheel rim (3), a fourth-stage wheel rim (4), a fifth-stage wheel rim (5), a first-stage inward-rotating blade (6), a first-stage outward-rotating blade (7), a second-stage inward-rotating blade (8), a second-stage outward-rotating blade (9), and a central blind plate (10), and the above structures together constitute a water removal device (11) unit.

2. The gypsum rain prevention and control equipment and system according to claim 1, characterized in that: The water removal device (11) is installed in the wet flue gas desulfurization absorption tower (12) and in the chimney (14) at the rear of the clean flue gas duct (13).

3. The gypsum rain prevention and control equipment and system according to claim 2, characterized in that: The water removal device (11) is installed on the upper part of the chimney inner tube (15), and the lower part of the chimney inner tube (15) is equipped with an arc bottom plate (16), a drain port (17) and a water pipe (18) so as to discharge the intercepted gypsum rain out of the system.

4. The gypsum rain prevention and control equipment and system according to claim 1, characterized in that: The water removal device (11) is a multi-layer circular impeller-shaped structure, and is provided with a central blind plate (10), wherein the diameters of the first-stage wheel rim (1), the second-stage wheel rim (2), the third-stage wheel rim (3), the fourth-stage wheel rim (4), and the fifth-stage wheel rim (5) are gradually reduced.

5. The gypsum rain prevention and control equipment and system according to claim 4, characterized in that: The first-stage inwardly rotating blade (6) is a clockwise, evenly distributed, centrally symmetrical n-stage blade with an α° inclination angle, installed between the first-stage wheel rim (1) and the second-stage wheel rim (2), and the inner and outer sides of the blade are fully welded to the wheel rim.

6. The gypsum rain prevention and control equipment and system according to claim 4, characterized in that: The first-stage outward rotating blade (7) is an N-stage blade with a β° inclination angle, which is counterclockwise, evenly distributed around the circumference, and centrally symmetrical. It is installed between the second-stage wheel rim (2) and the third-stage wheel rim (3), and the inner and outer sides of the blade are fully welded to the wheel rim.

7. The gypsum rain prevention and control equipment and system according to claim 4, characterized in that: The second-stage inwardly rotating blade (8) is a clockwise, evenly distributed, centrally symmetrical n-stage blade with an α° inclination angle, and is installed between the third-stage wheel rim (3) and the fourth-stage wheel rim (4), with the inner and outer sides of the blade being fully welded to the wheel rim.

8. The gypsum rain prevention and control equipment and system according to claim 4, characterized in that: The second-stage external rotating blade (9) is an N-stage blade with a β° inclination angle, which is counterclockwise, evenly distributed around the circumference, and centrally symmetrical. It is installed between the fourth-stage wheel rim (4) and the fifth-stage wheel rim (5), and the inner and outer sides of the blade are fully welded to the wheel rim.

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