Circulating fluidized bed desulfurizing tower

Abstract

The utility model discloses a circulating fluidized bed desulfurizing tower. The desulfurization tower at least comprises a desulfurization tower inlet section, a Venturi tube group, a divergent section, a straight tube section and an outlet section which are sequentially and continuously arranged from bottom to top, the desulfurizing tower inlet section comprises a square flue, a transition flue and a circular flue which are connected in sequence; the square flue comprises a 90-degree elbow, and a flue gas inlet is positioned on the horizontal square flue in front of the 90-degree elbow; the 90-degree elbow is internally provided with a flow guide device for preventing flue gas from generating bias flow after the flue gas passes through the elbow; and a rotational flow assembly is arranged at the divergent section of the desulfurizing tower. According to the utility model, when part of flue gas at the outlet of the Venturi tube enters the divergent section of the desulfurization tower, the flow direction is changed under the flow guide action of the blades to form rotational flow. Under the action of centrifugal force of rotational flow, more desulfurizing agents are thrown to the periphery of the desulfurizing tower and decelerated in the rising process, and then fall back to the divergent section, so that the proportion of the internal circulation desulfurizing agent is increased.

Description

Technical Field

[0001] The utility model relates to a circulating fluidized bed desulfurization tower. Background Art

[0002] According to the morphological characteristics of the desulfurizer and the desulfurization product, industrial flue gas desulfurization technology can be divided into three categories: wet method, dry method and semi-dry method. Among them, the semi-dry method has some characteristics of both the dry method and the wet method. The characteristic of this technology is the joint reaction in the three phases of gas, liquid and solid. The water in the wet desulfurizer is evaporated by the waste heat of the flue gas, and the final product is dry. Circulating fluidized bed desulfurization is a typical semi-dry flue gas desulfurization technology. It is based on the principle of circulating fluidized bed and uses slaked lime powder Ca(OH)2 as the absorbent. This technology sprays atomized water into the desulfurization tower, and through the internal circulation of the absorbent in the tower and multiple external circulations, the absorbent and the flue gas pollutants are fully contacted and reacted, thereby achieving a higher desulfurization efficiency.

[0003] Circulating fluidized bed flue gas desulfurization is currently widely used in power plant boilers, steel sintering and pelletizing flue gas purification and other fields. Compared with wet and dry desulfurization, it has the advantages of small footprint, no secondary pollution of wastewater, no need for equipment anti-corrosion, and low operating costs. When the Ca / S ratio of this technology is 1.3-1.5, the desulfurization efficiency can reach more than 95%, but compared with wet desulfurization, the desulfurization efficiency is slightly lower, and when the SO2 concentration in the flue gas is high, the Ca / S ratio needs to be increased to ensure that the outlet SO2 concentration meets the emission standards, resulting in increased operating costs.

[0004] In a traditional circulating fluidized bed desulfurization tower, the flue gas is accelerated through the Venturi section and then enters the gradually expanding section of the tower body. Under the action of the airflow, the solid desulfurizer at the center of the tower body gradually decreases in speed as it moves upward. When it rises to a certain height, a small part of the material falls back along the periphery of the tower, thus forming a fluidized bed layer with internal circulation. Since the overall movement direction of the absorbent in the desulfurization tower is vertically upward, the single residence time is limited by the tower height, and most of the desulfurizer leaves the tower with the airflow before reacting. In order to improve the utilization rate of the desulfurizer, a dust removal device is usually set downstream of the desulfurization tower, and most of the desulfurization ash captured by the dust removal device is returned to the interior of the desulfurization tower through the material circulation system, thereby increasing the total residence time. However, this will cause a large operating load on the subsequent dust removal equipment, thereby increasing the floor space and investment cost of the dust removal equipment.

[0005] In addition, due to the low flue gas flow rate around the tower, when the proportion of process water sprayed into the desulfurization tower is inappropriate, the wet desulfurizer will easily form on the wall inside the tower, affecting the stability of the desulfurization tower operation. Utility Model Content

[0006] In order to overcome the above defects, the purpose of the utility model is to provide a circulating fluidized bed desulfurization tower to solve the problems of short residence time of desulfurizer and easy wall formation of desulfurizer in traditional circulating fluidized bed desulfurization tower.

[0007] In order to achieve the above-mentioned purpose, the utility model provides a circulating fluidized bed desulfurization tower, which at least comprises a desulfurization tower inlet section, a venturi tube group, a gradually expanding section, a straight section, and an outlet section which are arranged successively from bottom to top;

[0008] The desulfurization tower inlet section comprises a square flue, a transition flue and a circular flue connected in sequence; the square flue comprises a 90° elbow, and the flue gas inlet is located on the horizontal square flue in front of the 90° elbow; a guide device is arranged in the 90° elbow to prevent the flue gas from deviating after passing through the bend;

[0009] A swirl component is arranged in the gradually expanding section of the desulfurization tower.

[0010] Furthermore, the venturi tube group comprises a plurality of symmetrically distributed venturi tubes, the lower inlet of the venturi tube is connected to the circular flue of the inlet section of the desulfurization tower, and the upper outlet is connected to the gradually expanding section of the desulfurization tower.

[0011] Furthermore, the gradually expanding section of the desulfurization tower is a conical barrel structure that is thicker at the top and thinner at the bottom.

[0012] Furthermore, the desulfurizing agent fresh material feed port and the circulating ash feed port are arranged at the circular flue of the desulfurization tower inlet section.

[0013] Furthermore, the desulfurization tower expansion section is provided with a process water spray gun.

[0014] Furthermore, the swirl assembly includes swirl blades arranged on the inner wall of the diverging section.

[0015] Furthermore, the swirl blades are arranged in a ring shape through an annular bracket; the annular bracket is connected to the inner wall of the gradually expanding section through a plurality of fixed ring connecting rods.

[0016] Furthermore, the number of the swirl blades is 15 to 30, and they are evenly arranged along the inner wall of the gradually expanding section of the desulfurization tower.

[0017] Furthermore, the angle between the swirl blade and the horizontal plane is 30° to 75°.

[0018] Furthermore, the following relationship is satisfied among the diameter d of the inscribed circle of the inner edge of the horizontal projection of the swirl blade, the diameter D1 of the circumscribed circle of the horizontal projection center of the peripheral Venturi tube, and the diameter D2 of the circumscribed circle of the Venturi outlet: 0.9D1≤d≤D1+0.5(D2-D1).

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] 1) The utility model is provided with swirl blades at the bottom of the desulfurization tower expansion section, i.e., at the outlet of the venturi tube group. When part of the flue gas at the outlet of the outer venturi tube enters the desulfurization tower expansion section, the flow direction will be changed to form a swirl under the flow guiding action of the blades. Under the action of the swirl, the airflow and desulfurizer in the tower rise in a spiral, which increases the residence time compared with the pure straight flow. On the other hand, under the centrifugal force of the swirl, more desulfurizer is thrown to the periphery of the desulfurization tower and decelerated during the rising process, and then falls back to the expansion section, thereby increasing the proportion of the internal circulation desulfurizer. While keeping the Ca / S ratio and the utilization rate of the desulfurizer unchanged, the proportion of the external circulation desulfurizer, i.e., the circulating ash, can be appropriately reduced, thereby reducing the load of the subsequent dust removal device, and reducing the land occupation and investment cost of the dust removal device. If the external circulation ratio is kept unchanged, the introduction of the swirl into the desulfurization tower through the bypass prolongs the total residence time of the desulfurizer, so that the desulfurizer reacts more fully with the pollutants in the flue gas, and improves the utilization rate of the desulfurizer, thereby reducing the Ca / S ratio, or improving the desulfurization efficiency while keeping the Ca / S ratio.

[0021] 2) The swirling flue gas in the gradually expanding section of the desulfurization tower can enhance the scouring effect of the flue gas on the inner wall of the desulfurization tower, and make the desulfurizer easier to break under the action of tangential force, reduce the risk of desulfurizer wall formation due to improper use of process water, and improve the operating stability of the desulfurization tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the longitudinal section structure of the desulfurization tower of the utility model.

[0023] Figure 2 It is a schematic diagram of the local structure of the swirl blades of the desulfurization tower of the utility model.

[0024] Figure 3 It is a top view of the local structure of the swirl blades of the desulfurization tower of the utility model.

[0025] In the figure: 1. desulfurization tower inlet section; 2. Venturi tube group; 3. Gradual expansion section; 4. Straight section; 5. Exit section; 6. Desulfurization agent new material feeding port; 7. Circulating ash feeding port; 8. Process water spray gun; 9. Inlet guide device; 10. Swirl blade; 11. Swirl blade fixing ring; 12. Fixing ring connecting rod. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions 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 device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The utility model provides a circulating fluidized bed desulfurization tower, which at least comprises a desulfurization tower inlet section, a venturi tube group, a gradually expanding section, a straight section, and an outlet section which are arranged in sequence from bottom to top; the desulfurization tower inlet section comprises a square flue, a transition flue, and a circular flue which are connected in sequence; the square flue comprises a 90° elbow, and the flue gas inlet is located on the horizontal square flue in front of the 90° elbow; a flow guide device is arranged in the 90° elbow to prevent the flue gas from generating a biased flow after passing through the bend;

[0030] A swirl assembly is provided in the desulfurization tower expansion section. The swirl assembly is preferably provided at the bottom of the desulfurization tower expansion section, corresponding to the outlet of the venturi tube group.

[0031] The embodiments of the utility model are described in detail below with reference to the accompanying drawings.

[0032] Example 1

[0033] A swirl-straight composite flow semi-dry circulating fluidized bed desulfurization tower comprises a desulfurization tower inlet section 1, a venturi tube group 2, a gradually expanding section 3, a straight section 4, an outlet section 5, a desulfurization agent new material feed port 6, a circulating ash feed port 7, a process water spray gun 8, and a swirl blade 10. The desulfurization tower inlet section 1 comprises a square flue, a transition flue, and a circular flue connected in sequence; the square flue comprises a 90° elbow, and the flue gas inlet is located on the horizontal square flue before the 90° elbow. A flow guide device 10 is arranged in the 90° elbow to prevent the flue gas from generating a biased flow after passing through the bend. A venturi tube 2 is arranged at the end of the circular flue of the desulfurization tower inlet section 1, and the outlet of the venturi tube 2 is connected to the gradually expanding section 3. After the flue gas enters the desulfurization tower inlet section 1, it flows through the venturi tube 2, the gradually expanding section 3, and the straight section 4 in sequence, and finally discharges the desulfurization tower through the outlet section 5.

[0034] The desulfurizer fresh material feeding port 6 and the circulating ash feeding port 7 are arranged at the circular flue of the desulfurization tower inlet section 1. The desulfurizer entering the desulfurization tower inlet section 1 is accelerated together with the flue gas through the venturi tube 2 and enters the gradually expanding section 3, and forms a fluidized bed in the gradually expanding section 3 and the straight section 4. The gradually expanding section 3 is provided with a process water spray gun 8 for spraying water into the flue gas to promote the desulfurization reaction.

[0035] The bottom of the desulfurization tower expansion section 3, i.e., the outlet of the venturi tube group 2, is provided with swirl blades 10. There are 20 swirl blades in total, which are evenly arranged along the inner wall of the expansion section 3. The angle between the swirl blades 10 and the horizontal plane is 45°. The diameter d of the inscribed circle of the inner edge of the horizontal projection of the swirl blade 10 is just equal to the diameter D1 of the circumscribed circle of the horizontal projection center of the peripheral venturi tube, i.e., about half of the flue gas at the outlet of the peripheral venturi tube will flow through the swirl blades 10 to form a swirl.

[0036] The outer edge of the swirl blade 10 is welded to the inner wall of the desulfurization tower expansion section 3, and two swirl blade fixing rings 11 are welded to the upper edge; fixing ring connecting rods 12 are welded between the swirl blade fixing rings 11 and between the fixing rings 11 and the inner wall of the expansion section 3.

[0037] Example 2

[0038] A swirl-straight composite flow semi-dry circulating fluidized bed desulfurization tower comprises a desulfurization tower inlet section 1, a venturi tube group 2, a gradually expanding section 3, a straight section 4, an outlet section 5, a desulfurization agent new material feed port 6, a circulating ash feed port 7, a process water spray gun 8, and a swirl blade 10. The desulfurization tower inlet section 1 comprises a square flue, a transition flue, and a circular flue connected in sequence; the square flue comprises a 90° elbow, and the flue gas inlet is located on the horizontal square flue before the 90° elbow. A flow guide device 10 is arranged in the 90° elbow to prevent the flue gas from generating a biased flow after passing through the bend. A venturi tube 2 is arranged at the end of the circular flue of the desulfurization tower inlet section 1, and the outlet of the venturi tube 2 is connected to the gradually expanding section 3. After the flue gas enters the desulfurization tower inlet section 1, it flows through the venturi tube 2, the gradually expanding section 3, and the straight section 4 in sequence, and finally discharges the desulfurization tower through the outlet section 5.

[0039] The desulfurizer fresh material feeding port 6 and the circulating ash feeding port 7 are arranged at the circular flue of the desulfurization tower inlet section 1. The desulfurizer entering the desulfurization tower inlet section 1 is accelerated together with the flue gas through the venturi tube 2 and enters the gradually expanding section 3, and forms a fluidized bed in the gradually expanding section 3 and the straight section 4. The gradually expanding section 3 is provided with a process water spray gun 8 for spraying water into the flue gas to promote the desulfurization reaction.

[0040] The bottom of the desulfurization tower expansion section 3, i.e., the outlet of the venturi tube group 2, is provided with swirl blades 10. There are 30 swirl blades in total, which are evenly arranged along the inner wall of the expansion section 3. The angle between the swirl blades 10 and the horizontal plane is 60°. The diameter d of the inscribed circle of the inner edge of the horizontal projection of the swirl blade 10 is between the diameter D1 of the circumscribed circle of the horizontal projection center of the peripheral venturi tube and the diameter D2 of the circumscribed circle of the venturi outlet, that is, a small part of the flue gas at the outlet of the peripheral venturi tube will flow through the swirl blades 10 to form a swirl.

[0041] The outer edge of the swirl blade 10 is welded to the inner wall of the desulfurization tower expansion section 3, and two swirl blade fixing rings 11 are welded to the upper edge; fixing ring connecting rods 12 are welded between the swirl blade fixing rings 11 and between the fixing rings 11 and the inner wall of the expansion section 3.

[0042] The utility model is described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the utility model. Many other changes and modifications that do not depart from the concept and scope of the utility model should be considered as the protection scope of the utility model.

[0043] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0044] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A circulating fluidized bed desulfurization tower, characterized in that: At least including a desulfurization tower inlet section, a venturi tube group, a gradually expanding section, a straight section, and an outlet section which are arranged successively from bottom to top; The desulfurization tower inlet section comprises a square flue, a transition flue and a circular flue connected in sequence; the square flue comprises a 90° elbow, and the flue gas inlet is located on the horizontal square flue in front of the 90° elbow; a guide device is arranged in the 90° elbow to prevent the flue gas from deviating after passing through the bend; A swirl component is arranged in the gradually expanding section.

2. The circulating fluidized bed desulfurization tower according to claim 1, characterized in that: The venturi tube group comprises a plurality of symmetrically distributed venturi tubes, wherein the lower inlet of the venturi tube is connected to the circular flue of the inlet section of the desulfurization tower, and the upper outlet is connected to the gradually expanding section of the desulfurization tower.

3. The circulating fluidized bed desulfurization tower according to claim 1, characterized in that: The gradually expanding section of the desulfurization tower is a conical barrel structure that is thick at the top and thin at the bottom.

4. The circulating fluidized bed desulfurization tower according to claim 1, characterized in that: The desulfurizing agent fresh material feed port and the circulating ash feed port are arranged at the circular flue of the desulfurizing tower inlet section.

5. The circulating fluidized bed desulfurization tower according to claim 1, characterized in that: A process water spray gun is provided in the expansion section of the desulfurization tower.

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