A limestone gypsum wet desulfurization tower internal slurry liquid level detection device

Abstract

The utility model provides a kind of limestone gypsum wet desulphurization tower inner slurry liquid level detection device, it is related to flue gas treatment technical field, comprising: double redundant setting liquid level transmitter, reducing tee, pressure lead main pipe, flushing branch pipe, flushing electric valve, exhaust electric valve and exhaust pipe;The large-diameter end of reducing tee is connected with absorption tower body, first small-diameter end is connected with the pressure sensing diaphragm of liquid level transmitter, and second small-diameter end is vertically set upwards;Pressure lead main pipe is vertically connected with the second small-diameter end of reducing tee, and extension height exceeds absorption tower highest design liquid level, and the top of pressure lead main pipe is connected with exhaust pipe, and upper portion of pressure lead main pipe is horizontally connected with flushing branch pipe;Flushing electric valve is installed on the flushing branch pipe, and exhaust electric valve is installed on the exhaust pipe.Accurate, stable, reliable measurement of slurry liquid level in desulphurization tower is realized, process control accuracy is improved, and it is suitable for reconstruction project, and investment cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of flue gas treatment technology, and in particular to a slurry level detection device inside a limestone-gypsum wet desulfurization tower. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] The limestone-gypsum wet desulfurization process has become the mainstream technology for flue gas desulfurization due to its significant advantages such as desulfurization efficiency of over 95%, wide applicability, and renewable resource utilization. It plays a crucial role in flue gas treatment in industries such as power and chemical engineering.

[0004] As the core equipment of this process, the stability of the slurry level in the absorption tower directly affects the continuous operation of the equipment and the emission data. However, because the tower body is a welded carbon steel structure, and the internal slurry has high corrosiveness, high abrasion, and easy sedimentation characteristics, the liquid level cannot be obtained through direct observation methods such as glass sight glasses, and indirect detection methods must be adopted.

[0005] Current conventional pressure transmitter testing methods have many shortcomings: (1) Bubble interference: The slurry is mixed with a large number of bubbles under the disturbance of the circulating pump, agitator and oxidizing air, which causes bubbles to accumulate in the existing pressure sensing pipe, resulting in the diaphragm pressure being too low and the liquid level measurement deviation being large; (2) Scaling effect: Solid particles in the slurry deposit and form scale on the membrane surface, and there is a lack of effective cleaning methods, which will continuously increase the measurement error during long-term operation; (3) Insufficient reliability: Most existing detection devices use a single level transmitter, which will cause data interruption and interfere with process control when a fault occurs. Utility Model Content

[0006] To address the shortcomings of existing technologies, this utility model provides a slurry level detection device inside a limestone-gypsum wet desulfurization tower. It eliminates bubble interference through an inclined reducing tee and a high-level pressure venting structure. Combined with an FRP pipeline pressurized flushing system and a dual-redundant transmitter configuration, it achieves continuous and accurate measurement of the highly corrosive slurry level, improves measurement accuracy, ensures stable operation of the desulfurization system, and reduces maintenance costs.

[0007] The liquid level detection device for the slurry inside the limestone-gypsum wet desulfurization tower includes: a dual redundant liquid level transmitter, a reducing tee, a pressure tapping main pipe, a flushing branch pipe, a flushing electric valve, an exhaust electric valve, and an exhaust pipe. The large-diameter end of the reducing tee is connected to the absorption tower body, the first small-diameter end is connected to the pressure-sensing diaphragm of the level transmitter, and the second small-diameter end is set vertically upward. The main pressure tapping pipe is vertically connected to the second smallest diameter end of the reducing tee pipe, and its extension height exceeds the highest design liquid level of the absorption tower. The top of the main pressure tapping pipe is connected to the exhaust pipe, and the upper part of the main pressure tapping pipe is horizontally connected to the flushing branch pipe. The flushing electric valve is installed on the flushing branch pipe, and the exhaust electric valve is installed on the exhaust pipe.

[0008] Furthermore, the reducing tee, pressure main pipe, flushing branch pipe, and exhaust pipe are all made of FRP (fiberglass reinforced plastic).

[0009] Furthermore, the center axis of the large-diameter end of the reducing tee is set upward at a 30° angle to the horizontal plane.

[0010] Furthermore, the second smaller diameter end of the reducing tee is directly connected to the mounting flange of the pressure-sensing diaphragm of the level transmitter.

[0011] Furthermore, the exhaust pipe ends in a tee or elbow configuration.

[0012] Furthermore, the vertical height of the pressure tapping main pipe is greater than the height difference between the highest design liquid level of the absorption tower and the interface of the absorption tower body.

[0013] Furthermore, the inlet end of the flushing branch pipe is connected to a pressurized process water pipeline.

[0014] Furthermore, the pressure-sensing diaphragms of the dual redundant level transmitters are connected in parallel to the first small-diameter end of the reducing tee.

[0015] Furthermore, both the exhaust electric valve and the flushing electric valve are flange-connected electric actuators.

[0016] Furthermore, it also includes a DCS control system, which is connected to the analog output terminal of the level transmitter, the on / off control terminals of the exhaust electric valve and the flushing electric valve via cables.

[0017] Compared with the prior art, the slurry level detection device inside the limestone-gypsum wet desulfurization tower provided by this utility model has the following beneficial effects: (1) In view of the technical problem of bubble interference, the present invention provides a 30° inclined design of the reducing tee and an ultra-high exhaust structure of the pressure tapping main pipe. The reducing tee structure guides the bubbles in the dead corner of the diaphragm into the pressure tapping main pipe. The characteristic that the air density is lower than that of the slurry makes the bubbles rise to the exhaust pipe and be discharged. At the same time, the height of the pressure tapping main pipe avoids the overflow of slurry, ensuring that the diaphragm is always filled with slurry, eliminating the interference of bubbles on pressure detection and improving the measurement accuracy.

[0018] (2) In response to the technical problem of increased deviation caused by diaphragm scaling, this utility model is based on FRP fiberglass pipe material, flushing branch pipe pressure cleaning system combined with DCS automatic control program, to regularly remove scale from pipes and diaphragms, thus avoiding measurement drift caused by solid deposits.

[0019] (3) In view of the technical problem of insufficient reliability of liquid level measurement, this utility model configures two redundant liquid level transmitters in parallel, measure simultaneously and compare in real time, which can detect instrument abnormalities in a timely manner, and does not affect the operation of the system when a single unit fails, thus realizing continuous and reliable monitoring of liquid level data and ensuring the stability of process parameter control. Attached Figure Description

[0020] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0021] Figure 1 This is a schematic diagram of the slurry level detection device inside the limestone-gypsum wet desulfurization tower disclosed in this utility model.

[0022] In the diagram: 1. Level transmitter; 2. Reducing tee; 3. Vertical main pressure pipe; 4. Flushing branch pipe; 5. Flushing electric valve; 6. Exhaust electric valve; 7. Exhaust pipe. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0024] Please see Figure 1 The present invention provides a liquid level detection device for slurry inside a limestone-gypsum wet desulfurization tower, comprising: a dual redundant liquid level transmitter (1), a reducing tee pipe (2), a pressure tapping main pipe (3), a flushing branch pipe (4), a flushing electric valve (5), an exhaust electric valve (6), and an exhaust pipe (7). The large-diameter end of the reducing tee (2) is connected to the absorption tower body, the first small-diameter end is connected to the pressure-sensing diaphragm of the level transmitter (1), and the second small-diameter end is set vertically upward. The pressure tapping main pipe (3) is vertically connected to the second small diameter end of the reducing tee pipe (2), and its extension height exceeds the highest design liquid level of the absorption tower. The top of the pressure tapping main pipe (3) is connected to the exhaust pipe (7), and the upper part of the pressure tapping main pipe (3) is horizontally connected to the flushing branch pipe (4). The flushing electric valve (5) is installed on the flushing branch pipe (4), and the exhaust electric valve (6) is installed on the exhaust pipe (7).

[0025] In this embodiment, the reducing tee (2), the pressure main pipe (3), the flushing branch pipe (4), and the exhaust pipe (7) are all made of FRP (fiberglass reinforced plastic). Utilizing the corrosion resistance, lightweight, and low cost characteristics of FRP, it is suitable for the highly corrosive environment of slurry. This extends the service life of the equipment, reduces material and maintenance costs, and solves the problem of easy corrosion of metal materials.

[0026] The center axis of the large-diameter end of the reducing tee (2) is inclined upward at a 30° angle to the horizontal plane. This reduces the deposition of slurry in the pipe and lowers the risk of pipe blockage. It also optimizes the slurry flow path, avoids the accumulation of solid particles, maintains the smooth flow of the pipe, and ensures the stability of pressure transmission.

[0027] The second smaller diameter end of the reducing tee (2) is directly connected to the mounting flange of the pressure-sensing diaphragm of the level transmitter (1). This shortens the path of air bubbles from the dead corner of the diaphragm to the main pressure pipe, reduces the residence time of air bubbles near the diaphragm, and ensures that air bubbles are discharged quickly.

[0028] The exhaust pipe (7) is terminated in a tee or elbow structure. This prevents external impurities such as rain and snow from entering the exhaust pipe and contaminating or clogging the pipeline, while ensuring smooth air discharge and maintaining the long-term stability of the exhaust function.

[0029] The vertical height of the pressure tap (3) is greater than the height difference between the highest design liquid level of the absorption tower and the interface of the absorption tower body, ensuring that the slurry will not overflow from the exhaust pipe during normal operation, only air will be discharged, eliminating the risk of slurry overflow and ensuring the balance between exhaust function and measurement safety.

[0030] The inlet end of the flushing branch pipe (4) is connected to the pressurized process water pipeline. The impact force of pressurized clean water is used to thoroughly clean the scale on the pipeline and diaphragm surface, ensuring the sensitivity of the diaphragm pressure sensing and maintaining long-term measurement accuracy.

[0031] The pressure-sensing diaphragm of the dual redundant level transmitter (1) is connected in parallel to the first small diameter end of the reducing tee (2) to realize dual data acquisition and comparison at the same measuring point. They are redundant to each other. The system can still operate when a single unit fails, and can quickly identify abnormal data, thus improving the reliability of detection.

[0032] Both the exhaust electric valve (6) and the flushing electric valve (5) are flange-connected electric actuators, which ensure the sealing reliability of the valve and pipeline, facilitate remote control and maintenance, reduce leakage risk, meet the needs of automated control, and reduce on-site maintenance workload.

[0033] The device also includes a DCS control system, which is existing technology. This invention does not improve the software algorithm. The control system is connected to the analog output terminal of the level transmitter (1), the on / off control terminals of the exhaust electric valve (6) and the flushing electric valve (5) via cables. It realizes real-time monitoring of level data, anomaly judgment and automatic valve switching (exhaust / flushing mode), replacing manual operation, improving response speed and ensuring the adaptive operation of the system under complex working conditions.

[0034] In this embodiment, the level transmitter senses the pressure of the slurry at the inlet pipe through a diaphragm (made of Hastelloy alloy). The current signal is transmitted to the control system and converted into the liquid level in the absorption tower according to the height-pressure conversion formula. It is designed as a dual-redundant scheme, which can obtain two liquid level data and the average value to increase the reliability and comparability of the detection system. However, the prerequisite for ensuring accurate measurement is that the inlet pipe is full of liquid and the influence of mixed air must be eliminated. Otherwise, the sensed pressure data will be too small and fluctuate greatly, and the liquid level will be too small and fluctuate greatly, making it impossible to measure stably. The reducing tee (DN80*80-25) is made of FRP (fiberglass reinforced plastic) and features a flange connection. The larger diameter end connects to the absorption tower body pipe, and the other end connects to the pressure-sensing diaphragm of the level transmitter. The smaller diameter end connects to the pressure-sensing pipe. Through component angle design, the larger diameter end is tilted upwards at 30° after installation to reduce slurry deposition inside the pipe. Simultaneously, the smaller diameter end is designed to be close to the pressure-sensing diaphragm to ensure that air accumulated in dead zones can be easily discharged into the vertical pressure-sensing pipe, and that flushing water can easily rinse the diaphragm. This series of designs ensures that the pressure-sensing diaphragm is in a full liquid state, eliminating the influence of air on measurement, enhancing the flushing effect, and avoiding measurement deviations caused by scale buildup. The vertical pressure-pressurizing main pipe is made of FRP (fiberglass reinforced plastic), which is corrosion-resistant and cost-effective. The internal liquid is a slurry mixed with air, which enters from the absorption tower under static pressure through a reducing tee. Because air has a very low density, the air mixed with the slurry will penetrate the slurry and rise to the outlet within the vertical pipe. Simultaneously, because the height of the vertical pipe exceeds the design liquid level of the absorption tower, it ensures that the slurry inside the tower will not overflow during normal measurement. This achieves continuous air discharge and guarantees a full liquid state at the measuring end of the reducing tee. One end of the flushing branch pipe is connected to the upper part of the pressure-inducing vertical main pipe, and the other end is connected to the flushing water valve to introduce pressurized flushing water from the process water system, thereby flushing the vertical pipes, reducing tees and pressure-sensing diaphragms and preventing slurry deposition from clogging the pipes. The flushing water electric valve is controlled by the central control system. Under normal measurement conditions, it is in the closed state to prevent backflow of slurry or moisture from corroding the process water pipeline upstream of the valve. If the central control system detects an abnormal slurry pressure signal, such as being too low, fluctuating beyond limits, or remaining stationary for a long time, it determines that there is a blockage in the pipeline or slurry buildup. The valve is then remotely opened to introduce pressurized process water to flush and clean the system. This valve can be programmed to open periodically or automatically under abnormal conditions. The exhaust electric valve is also controlled by the central control system. Under normal measurement conditions, it is in the open state to ensure that the air in the pressurized vertical pipe can be continuously and smoothly discharged. When the system malfunctions and requires flushing, the flushing water valve and this valve are remotely switched to ensure the pressure of the introduced process water. After the flushing cycle is completed, it returns to the original open state to continue measurement. The interlocking switching of this valve is completed automatically by the program. The exhaust pipe terminal is in the form of a tee or elbow, and is made of corrosion-resistant FRP fiberglass. The slurry air rises through the vertical pipe and is discharged to the outside atmosphere from here, while preventing rain and snow from entering the system. The DCS control system is an existing system. By connecting the on / off control circuit of the exhaust / flushing electric valve and the analog signal of the level transmitter, it monitors the liquid levels at two locations and the average liquid level. Simultaneously, it monitors for abnormal measurements and issues commands to automatically switch between the two electric valves. All of this can be performed automatically within the program, eliminating the need for manual operation.

[0035] In some renovation projects, the use of an online concentration detection device for limestone slurry preparation in wet desulfurization has ensured the stability and efficiency of the desulfurization system while reducing investment costs, making it an extremely economical technological measure.

[0036] The working principle of this utility model: The liquid level detection device inside the limestone-gypsum wet desulfurization tower includes: a level transmitter (dual redundant units), a reducing tee (DN80*80-25), a pressure tapping main pipe, a flushing branch pipe, a flushing electric valve, an exhaust electric valve, an exhaust pipe, and a DCS control system (existing technology).

[0037] The reducing tee, pressure main pipe, flushing branch pipe, and exhaust pipe are made of FRP (fiberglass reinforced plastic), which is lightweight, corrosion-resistant, and low-cost.

[0038] The larger diameter side of the reducing tee connects to the process flange of the absorber body, while the other side connects to the pressure-sensing diaphragm of the existing pressure transmitter. The smaller diameter side, pointing vertically upwards, connects to the main pressure tapping pipe. The main pressure tapping pipe extends upwards beyond the highest liquid level in the absorber, connecting to the horizontal flushing branch pipe, and continues upwards to the vent. Both the flushing branch pipe and the vent are equipped with electric valves, which are opened and closed by the control system.

[0039] When the system is running, after the short-circuit flange valve of the absorption tower body is opened, the slurry will flow into the newly added reducing tee pipe. After the pressure-sensing diaphragm of the level transmitter senses the pressure data, the signal is transmitted to the DCS control system in real time. The level can be obtained by converting the pressure and height using the formula.

[0040] Considering the reliability requirements of liquid level as a key parameter, the liquid level transmitter is equipped with redundant configuration. Two sets of liquid level transmitters measure and compare simultaneously, which can promptly detect anomalies of individual instruments, and the shutdown of individual instruments during processing does not affect the normal measurement of system parameters.

[0041] As the slurry flows in, a large amount of air simultaneously enters the pressure-sensing diaphragm of the level transmitter. To eliminate air interference, during normal operation, the exhaust electric valve at the top of the pressure-sensing main pipe remains open. At the same time, the designed reducing tee has its smaller diameter side biased towards the pressure-sensing diaphragm side, i.e., close to the mounting flange, which allows air accumulated in the dead corner of the diaphragm to be discharged into the pressure-sensing main pipe.

[0042] Because air is much less dense than slurry, it is forced into the pressure tapping main pipe by the slurry, ensuring that the diaphragm is always filled with slurry and avoiding dead air zones, thus guaranteeing accurate measurements. Simultaneously, because the exhaust valve is open, the air entering the pressure tapping main pipe rises within the pipe until it is expelled.

[0043] Because the vertical height of the exhaust pipe is higher than the designed height of the slurry inside the absorption tower, no slurry will overflow from the exhaust port; only air will be discharged.

[0044] The slurry is a high-density liquid containing a large number of insoluble solid particles, which can deposit or adhere to the surface of the pressure-sensing diaphragm, causing pressure deviations. At this time, the control system issues a command to open the flushing water valve, injecting pressurized clean water through the designed flushing water branch pipe to flush the entire pressure-sensing pipeline and diaphragm, maintaining the clean operation of the system.

[0045] Both sets of electric valves are controlled by the central control system, enabling automatic operation. Under normal measurement conditions, the exhaust main electric valve is open, while the flushing water pipe electric valve is closed. The pressure main pipe is filled with slurry, and gas is continuously discharged, allowing for continuous measurement. Simultaneously, by programming abnormal fluctuations in slurry density and measurement data, when high solids content or data deviating from normal values ​​occur, the control system issues a command to close the exhaust main electric valve and open the flushing water pipe electric valve. This flushes the pipeline, clearing blockages and cleaning diaphragm deposits. After the cycle is complete, the valves switch back to the original measurement state.

[0046] This invention achieves indirect real-time measurement of liquid level by setting up a level transmitter and converting pressure and height together. The configuration of two redundant level transmitters increases measurement reliability and comparability, facilitates the stability of key parameters, and enables timely detection of anomalies. The design of the pressure tapping and venting pipelines in the measuring device enables continuous and stable measurement of the liquid level within the absorption tower, eliminating the influence of air mixed in the slurry on the pressure sensing diaphragm. The flushing device's periodic circulation cleaning of the system prevents blockage of the pressure tapping pipelines by high-density slurry and the accumulation of scale on the pressure-sensing diaphragm. The data monitoring and sequential control program of the control system enable automatic valve switching, reducing manual workload and achieving automated operation of the entire system. This structure, while ensuring the stability and efficiency of the desulfurization system, reduces investment costs and improves process control accuracy, making it an extremely economical technology for retrofit projects.

[0047] In the description of this specification, the terms "connection", "installation", "fixing", "setting", etc. are interpreted in a broad sense. For example, "connection" can be a fixed connection or an indirect connection through an intermediate component without affecting the relationship between components and the technical effect. It can also be an integral connection or a partial connection. In such cases, those skilled in the art can understand the specific meaning of the above terms in this utility model or utility model according to the specific circumstances.

[0048] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A device for detecting the liquid level of slurry inside a limestone-gypsum wet desulfurization tower, characterized in that, include: The system includes a dual redundant level transmitter (1), a reducing tee pipe (2), a pressure tapping main pipe (3), a flushing branch pipe (4), a flushing electric valve (5), an exhaust electric valve (6), and an exhaust pipe (7). The large-diameter end of the reducing tee (2) is connected to the absorption tower body, the first small-diameter end is connected to the pressure-sensing diaphragm of the level transmitter (1), and the second small-diameter end is set vertically upward. The pressure tapping main pipe (3) is vertically connected to the second small diameter end of the reducing tee pipe (2), and its extension height exceeds the highest design liquid level of the absorption tower. The top of the pressure tapping main pipe (3) is connected to the exhaust pipe (7), and the upper part of the pressure tapping main pipe (3) is horizontally connected to the flushing branch pipe (4). The flushing electric valve (5) is installed on the flushing branch pipe (4), and the exhaust electric valve (6) is installed on the exhaust pipe (7).

2. The apparatus as claimed in claim 1, characterized in that, The reducing tee (2), the pressure main pipe (3), the flushing branch pipe (4), and the exhaust pipe (7) are all made of FRP (fiberglass reinforced plastic).

3. The apparatus as described in claim 1, characterized in that, The central axis of the large-diameter end of the reducing tee (2) is inclined upward at a 30° angle to the horizontal plane.

4. The apparatus as described in claim 1 or 3, characterized in that, The second smaller diameter end of the reducing tee (2) is directly connected to the mounting flange of the pressure-sensing diaphragm of the level transmitter (1).

5. The apparatus as claimed in claim 1, characterized in that, The exhaust pipe (7) has a tee or elbow structure at its end.

6. The apparatus as claimed in claim 1, characterized in that, The vertical height of the pressure tap (3) is greater than the height difference between the highest design liquid level of the absorption tower and the interface of the absorption tower body.

7. The apparatus as claimed in claim 1, characterized in that, The inlet end of the flushing branch pipe (4) is connected to a pressurized process water pipeline.

8. The apparatus as claimed in claim 1, characterized in that, The pressure-sensing diaphragm of the dual redundant level transmitter (1) is connected in parallel to the first small-diameter end of the reducing tee (2).

9. The apparatus as claimed in claim 1, characterized in that, Both the exhaust electric valve (6) and the flushing electric valve (5) are flange-connected electric actuators.

10. The apparatus as claimed in claim 1, characterized in that, It also includes a DCS control system, which is connected to the analog output terminal of the level transmitter (1), the on / off control terminal of the exhaust electric valve (6) and the flushing electric valve (5) via cables.

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