CFB semi-dry desulfurization tower
By setting up jet pipes and pipeline structures in the CFB semi-dry desulfurization tower, the flow of flue gas was optimized, the problem of unreacted desulfurizing agent discharge was solved, and desulfurization efficiency was improved and costs were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG TUNA ENVIRONMENTAL SCI & TECH
- Filing Date
- 2025-06-23
- Publication Date
- 2026-06-19
AI Technical Summary
In the ultra-low emission retrofit of existing CFB semi-dry desulfurization towers, unreacted desulfurizing agent is discharged as desulfurization ash, resulting in excessive consumption of desulfurizing agent and increased operating costs.
In the CFB semi-dry desulfurization tower, by setting three sets of jet pipes in the inverted cone section, the flue gas is tangentially introduced into the inverted cone section above the Venturi section, forming a spiral upward, which fully mixes with the desulfurizing agent, improving the mass transfer efficiency. The flue gas flow rate is controlled through the main pipeline and branch pipelines to reduce the system resistance.
It improves desulfurization efficiency, reduces the calcium-to-sulfur ratio, thereby reducing desulfurizing agent consumption, lowering operating costs, and saving system power consumption.
Smart Images
Figure CN224371091U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of flue gas desulfurization technology, and more specifically, to a CFB semi-dry desulfurization tower. Background Technology
[0002] In recent years, steel companies have successively completed ultra-low emission retrofits of flue gas desulfurization equipment in production lines such as sintering machines. Among these ultra-low emission retrofit projects, circulating fluidized bed (CFB) semi-dry flue gas desulfurization technology has been widely adopted.
[0003] According to the principle of semi-dry flue gas desulfurization technology, to achieve the designed ultra-low emission desulfurization efficiency, a high calcium-to-sulfur ratio of over 1.4 must be maintained in the CFB desulfurization tower. This means that the amount of calcium-based desulfurizing agent in the desulfurization system must be more than 1.4 times the amount required for the theoretical desulfurization chemical reaction. This results in a large amount of unreacted desulfurizing agent (mainly calcium hydroxide) in the desulfurization ash discharged from the desulfurization system. This unreacted desulfurizing agent is directly discharged as desulfurization ash, which is equivalent to consuming a large amount of additional desulfurizing agent and increasing the operating cost of the desulfurization system.
[0004] Therefore, a new solution is needed to address the above problems. Utility Model Content
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a CFB semi-dry desulfurization tower.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A CFB semi-dry desulfurization tower includes a tower body and a flue gas inlet and a flue gas outlet disposed on the tower body and connected to the inner cavity of the tower body. The tower body includes a vertical section, an inverted cone section and a Venturi section from top to bottom. A desulfurizing agent nozzle is installed in the inner cavity at the top of the inverted cone section. Three sets of jet pipes are evenly distributed on the outer circumference of the bottom of the inverted cone section. All three sets of jet pipes are connected to the flue gas inlet. Part of the flue gas in the flue gas inlet is guided by the jet pipes and tangentially injected into the inner cavity of the inverted cone section above the Venturi section, where it merges with the flue gas entering the inverted cone section from the Venturi section and forms a spiral upward.
[0008] Furthermore, the flue gas flow rate and inlet pressure are consistent across the three sets of jet tubes.
[0009] Furthermore, a main pipe connected to the flue gas inlet is provided on the outside of the flue gas inlet, and part of the flue gas in the flue gas inlet flows to three sets of jet pipes through the main pipe.
[0010] Furthermore, the main pipeline is connected to a branch pipeline at its end. The branch pipeline is arranged around the inverted cone section, and the two ends of the branch pipeline are connected together. The branch pipeline is connected to three sets of jet pipes.
[0011] Furthermore, the branch pipeline is provided with an inspection port corresponding to the jet pipe position.
[0012] Furthermore, a switch mechanism for controlling the opening and closing of the main pipeline is installed on the main pipeline.
[0013] Furthermore, the main pipeline is equipped with an adjustment mechanism for controlling the flow rate of flue gas in the main pipeline.
[0014] The beneficial effects of this utility model are:
[0015] 1. In this utility model, a portion of the flue gas in the flue gas inlet is guided to three sets of jet pipes. The flue gas is tangentially injected into the inverted cone section above the Venturi section through the jet pipes, and merges with the flue gas that has accelerated through the Venturi section into the inverted cone section. In the inverted cone section, a spiral upward formation is formed, which enhances the mass transfer and absorption reaction between the flue gas and the desulfurizing agent, improves the desulfurization efficiency, and reduces the calcium-sulfur ratio in the desulfurization tower. This allows for more full utilization of the desulfurizing agent, reduces consumption, and lowers the operating cost of the desulfurization system.
[0016] 2. In this utility model, by guiding part of the flue gas in the flue gas inlet to the jet pipe, the amount of flue gas passing through the Venturi section is reduced, thereby reducing the overall design resistance of the desulfurization tower and saving system power consumption. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of a CFB semi-dry desulfurization tower in this embodiment;
[0018] Figure 2 This is a schematic diagram of a connection structure between the branch pipe and the jet pipe in this embodiment.
[0019] Attached reference numerals: 1. Tower body, 101. Vertical section, 102. Inverted cone section, 103. Venturi section, 103. Flue gas inlet, 2. Flue gas outlet, 3. Desulfurizing agent nozzle, 4. Jet pipe, 5. Main pipeline, 6. Branch pipeline, 7. Inspection port, 8. Switching mechanism, 9. Adjusting mechanism, 10. Detailed Implementation
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0021] Example: A CFB semi-dry desulfurization tower, such as Figure 1 and Figure 2As shown, the structure includes a tower body 1, and a flue gas inlet 2 and a flue gas outlet 3 installed on the tower body 1. Both the flue gas inlet 2 and the flue gas outlet 3 are connected to the inner cavity of the tower body 1. The tower body 1 includes a vertical section 101, an inverted conical section 102, and a Venturi section 103 along its vertical direction from top to bottom. The vertical section 101 has a cylindrical structure and is located at the top of the inverted conical section 102. The inverted conical section 102 has a conical structure, and the Venturi section 103 is located at the bottom of the inverted conical section 102. A desulfurizing agent nozzle 4 is installed in the inner cavity at the top of the inverted conical section 102. The desulfurizing agent nozzle 4 is used to spray the desulfurizing agent (mainly calcium hydroxide, in dry powder form) into the vertical section 101. The desulfurizing agent nozzle 4 is a commercially available product. Any desulfurizing agent nozzle 4 that can be used in this desulfurization tower can be purchased. Its installation and usage methods are publicly available technologies in this field, and the technology is relatively mature. There is no need to optimize or innovate it, so it will not be described in detail, nor will it be protected. Preferably, an atomizing nozzle is also installed inside the vertical section 101. The atomizing nozzle is located above the desulfurizing agent nozzle 4 and is used to spray water onto the vertical section 101 to cool and humidify it.
[0022] In operation, the flue gas to be treated flows into the inner cavity of the tower body 1 through the flue gas inlet 2. The flue gas then enters the vertical section 101 through the Venturi section 103 and the inverted cone section 102, where it comes into contact with the desulfurizing agent sprayed from the desulfurizing agent nozzle 4 and reacts to achieve desulfurization. The desulfurized flue gas is then discharged through the flue gas outlet 3. The Venturi section 103 contains a Venturi tube. The throat contraction design of the Venturi tube significantly increases the flue gas velocity, creating a high-speed turbulent flow. This turbulence promotes thorough mixing of the flue gas and the injected desulfurizing agent, enhancing the gas-solid contact efficiency. The technique of increasing the flue gas velocity through the throat contraction of the Venturi tube is well-known and common among those skilled in the art; therefore, it will not be described in detail or protected.
[0023] The inverted cone section 102, due to its inverted cone structure, allows the flue gas to diffuse in the inverted cone section 102 when it flows from the Venturi section 103 to the vertical section 101, thus ensuring that the flue gas comes into contact with the desulfurizing agent.
[0024] Furthermore, such as Figure 1 and Figure 2 As shown, three sets of jet pipes 5 are evenly distributed on the outer circumference of the bottom of the inverted cone section 102, that is, the included angle between two adjacent sets of jet pipes 5 is 120°. All three sets of jet pipes 5 are connected to the flue gas inlet 2. Part of the flue gas in the flue gas inlet 2 is guided by the jet pipes 5 and tangentially injected into the inner cavity of the inverted cone section 102 above the Venturi section 103.
[0025] A stream of flue gas is drawn from flue gas inlet 2, bypasses the Venturi section 103, and enters the inverted cone section 102 tangentially through three sets of jet pipes 5 above the Venturi section 103. It merges with the flue gas that has accelerated into the inverted cone section 102 after passing through the Venturi section 103, and forms a spiral ascent in the inverted cone section 102. This enhances the mixing of flue gas and desulfurizing agent in a turbulent state. Based on the strong mass transfer mechanism of multi-directional turbulent mixing, and utilizing the principle of gas dynamics, a turbulent absorption space with rotating and churning airflow is generated. This allows for more complete contact between gas and solid, reduces the mass transfer resistance of the desulfurization reaction, increases the mass transfer rate, and accelerates the completion of the desulfurization reaction process, thereby achieving the goal of improving desulfurization efficiency.
[0026] By adopting the above structural design, under the same desulfurization efficiency, the actual calcium-sulfur ratio in the CFB desulfurization system can be reduced from 1.4~1.6 to below 1.2, and the consumption of desulfurization absorbent can be reduced by 15%~20%, thereby reducing the desulfurization operating cost.
[0027] Preferably, the inlet pressures of the three sets of jet pipes 5 are the same or nearly the same, and the flue gas flow rates of the three sets of jet pipes 5 are the same, so as to facilitate the formation of a balanced swirling flow field in the inverted cone section 102. Simultaneously, the pipe diameters of the three sets of jet pipes 5 are the same, and the angle at which each set of jet pipes 5 enters the inverted cone section 102 is uniformly designed based on the flow field simulation calculation results. The pipe diameter of each set of jet pipes 5 depends on the total flue gas flow rate to be diverted and the flow velocity design of the jet pipe 5. The jet pipes 5 are made of carbon steel, and the wall thickness of the jet pipes 5 is not less than 6mm.
[0028] Furthermore, such as Figure 1 As shown, a main pipe 6 connected to the flue gas inlet 2 is provided on the outside of the flue gas inlet 2. Using the main pipe 6, part of the flue gas in the flue gas inlet 2 can be diverted to the three sets of jet pipes 5. The main pipe 6 is made of carbon steel and the pipe wall thickness is not less than 6mm.
[0029] A branch pipe 7 is connected to the end of the main pipe 6, meaning the branch pipe 7 is connected to the main pipe 6. The branch pipe 7 is located outside the inverted cone section 102 and is arranged around the inverted cone section 102. The two ends of the branch pipe 7 are connected, and each branch pipe 7 is connected to one of the three sets of jet pipes 5. Part of the flue gas in the flue gas inlet 2 flows to the branch pipe 7 through the main pipe 6. Because the two ends of the branch pipe 7 are connected, this part of the flue gas is split at the connection between the branch pipe 7 and the main pipe 6, and flows to the three sets of jet pipes 5 respectively. The branch pipe 7 is made of carbon steel, and the pipe wall thickness is not less than 6mm.
[0030] Furthermore, the branch pipe 7 is provided with an inspection port 8 corresponding to the position of the jet pipe 5, that is, there are three inspection ports 8, which correspond one-to-one with the three sets of jet pipes 5; by providing inspection ports 8, it is convenient to inspect the jet pipes 5.
[0031] Furthermore, a switching mechanism 9 for controlling the opening and closing of the main pipeline 6 is installed on the main pipeline 6. The switching mechanism 9 can be a gate valve, which opens or closes the main pipeline 6 to achieve the opening or closing of the main pipeline 6. Preferably, two switching mechanisms 9 are provided, which can be used simultaneously or individually. When used individually, one of the switching mechanisms 9 serves as a backup. The gate valve is a commercially available product. Any gate valve that can be used in this desulfurization tower can be selected. Its installation and usage methods are publicly available technologies in this field, and the technology is relatively mature. There is no need to optimize or innovate it, so it will not be described in detail, nor will it be protected.
[0032] Furthermore, a regulating mechanism 10 for controlling the flue gas flow rate of the main pipeline 6 is installed on the main pipeline 6. The regulating mechanism 10 can be a regulating valve. By setting the regulating mechanism 10, the percentage adjustment of the conduction amplitude of the main pipeline 6 can be realized, thereby adjusting the flue gas flow rate injected from the jet pipe 5 to the inverted cone section 102. The regulating valve is a commercially available product. Any regulating valve that can be used in this desulfurization tower can be selected. Its installation and usage methods are publicly available technologies in this field, and its technology is relatively mature. There is no need to optimize or innovate it, so it will not be described in detail, nor will it be protected.
[0033] By drawing a stream of flue gas from flue gas inlet 2 and having it flow into the inverted cone section 102 of the desulfurization tower via regulating mechanism 10, the amount of flue gas passing through the Venturi section 103 is reduced, resulting in a decrease of over 10% in the overall design resistance of the desulfurization tower. This reduction in desulfurization system resistance directly translates to a decrease in the operating frequency and current of the main induced draft fan, thereby saving system power consumption. When the main unit's capacity is adjusted or the total flue gas volume of the desulfurization system decreases, the flow rate of the flue gas drawn from flue gas inlet 2 can be adjusted to adapt to changes in the total desulfurization load. Furthermore, the operating frequency of the main induced draft fan can be lowered based on the actual flue gas load changes, reducing energy consumption. Compared to the traditional CFB semi-dry desulfurization system, which increases clean flue gas recirculation and internal circulating air volume without reducing the induced draft fan frequency, the regulation scheme designed in this embodiment is more energy-efficient.
[0034] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.
Claims
1. A CFB semi-dry desulfurization tower, comprising a tower body (1), and a flue gas inlet (2) and a flue gas outlet (3) disposed on the tower body (1) and communicating with the inner cavity of the tower body (1), wherein the tower body (1) comprises, from top to bottom, a vertical section (101), an inverted conical section (102) and a Venturi section (103), and a desulfurizing agent nozzle (4) is installed in the inner cavity at the top of the inverted conical section (102), characterized in that, Three sets of jet pipes (5) are evenly distributed on the outer circumference of the bottom of the inverted cone section (102). All three sets of jet pipes (5) are connected to the flue gas inlet (2). Part of the flue gas in the flue gas inlet (2) is guided by the jet pipes (5) and tangentially injected into the inner cavity of the inverted cone section (102) above the Venturi section (103), where it merges with the flue gas entering the inverted cone section (102) from the Venturi section (103) to form a spiral upward.
2. The CFB semi-dry desulfurization tower according to claim 1, characterized in that, The flue gas flow rate and inlet pressure of the three sets of jet tubes (5) are the same.
3. The CFB semi-dry desulfurization tower according to claim 1, characterized in that, A main pipe (6) connected to the flue gas inlet (2) is provided on the outside of the flue gas inlet (2), and part of the flue gas in the flue gas inlet (2) flows to the three sets of jet pipes (5) through the main pipe (6).
4. The CFB semi-dry desulfurization tower according to claim 3, characterized in that, The main pipe (6) is connected to a branch pipe (7) at its end. The branch pipe (7) is arranged around the inverted cone section (102), and the two ends of the branch pipe (7) are connected together. The branch pipe (7) is connected to three sets of jet pipes (5).
5. A CFB semi-dry desulfurization tower according to claim 4, characterized in that, The branch pipe (7) is provided with an inspection port (8) at the position corresponding to the jet pipe (5).
6. The CFB semi-dry desulfurization tower according to claim 3, characterized in that, The main pipeline (6) is equipped with a switch mechanism (9) for controlling the opening and closing of the main pipeline (6).
7. A CFB semi-dry desulfurization tower according to claim 3, characterized in that, The main pipe (6) is equipped with an adjustment mechanism (10) for controlling the flow rate of flue gas in the main pipe (6).