Supersonic gas-liquid separation energy-saving demisting device and demisting method thereof

Abstract

The present application relates to the field of mist eliminator in wet desulfurization and denitrification process, and particularly relates to an ultrasonic gas-liquid separation energy-saving mist eliminator and a mist elimination method thereof. The device comprises a pressurized smoke inlet system, a flue gas compression system, a multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline, a smoke inlet and outlet control system and a liquid collector. The flue gas compression system is connected to the pressurized smoke inlet system. The multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline is connected to the flue gas outlet of the flue gas compression system, and is used to accelerate the flue gas entering the pipeline to supersonic speed to realize gas-liquid separation at the end of the Laval nozzle. The smoke inlet and outlet control system is used to control the corresponding smoke inlet and outlet of the flue gas compression system to open alternately. The liquid collector is connected to the outlet of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline through the side wall, and is provided with a gas outlet at the top. The present application has high mist elimination efficiency and good economy, and is suitable for large-scale industrial flue gas treatment.

Description

Technical Field

[0001] This invention relates to the field of demisters in wet desulfurization and denitrification processes, specifically to a supersonic gas-liquid separation energy-saving demister and its demister method. Background Technology

[0002] Industrial demisters are a crucial component of desulfurization and denitrification processes. Their primary function is to capture and recover slurry droplets from the flue gas used for desulfurization and denitrification, preventing the slurry from being carried into downstream equipment and causing pollution, corrosion, scaling, and ultimately, downtime or damage to the downstream equipment. Most existing industrial demisters are corrugated plate demisters, which utilize inertial impaction to capture droplets at the bends of the plates, ultimately achieving gas-liquid separation under gravity. However, in this type of demister, the corrugated plates only capture flue gas droplets at the bends and are prone to secondary entrainment, resulting in low demisting efficiency. Electrostatic demisters also exist, but these add extra energy consumption, making them uneconomical for large-scale flue gas treatment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a supersonic gas-liquid separation energy-saving demisting device with high demisting efficiency, good economy and suitable for large-scale industrial flue gas treatment.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a supersonic gas-liquid separation energy-saving demisting device, comprising:

[0005] Pressurized smoke intake system;

[0006] The flue gas compression system has its flue gas inlet connected to the pressurized flue gas inlet system;

[0007] A multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline is connected to the exhaust port of the flue gas compression system, and is used to accelerate the flue gas entering it to supersonic speed so that the flue gas achieves gas-liquid separation at the end of its Laval nozzle.

[0008] The flue gas compression system is used to control the corresponding flue gas inlet and outlet to open alternately.

[0009] The liquid collector has its sidewall connected to the outlet of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline, and a gas outlet is provided at the top.

[0010] A further specific structure of a pressurized smoke inlet system is provided, the pressurized smoke inlet system including a smoke inlet duct and a smoke inlet fan, the smoke inlet fan being disposed within the smoke inlet duct.

[0011] A further provision provides a specific structure of a flue gas compression system, the flue gas compression system comprising:

[0012] An even number of compression chambers are divided into two groups, each compression chamber having the exhaust port and the inlet port, and is slidably fitted with a pressure plate;

[0013] The crankshaft connecting rod mechanism includes a rotating crank and connecting rods corresponding to the compression chambers. One end of the connecting rod is hinged to the air compressor plate, and the other end is rotatably connected to the rotating crank. During rotation, the rotating crank drives the air compressor plates to slide through the connecting rods, so that the two sets of compression chambers are always in a state of one set of air intake and one set of air compression.

[0014] An electric motor is connected to the rotating crank to drive the rotating crank to rotate; wherein,

[0015] The crank is also connected to the impeller of the smoke inlet fan to drive the impeller to rotate during its rotation;

[0016] The smoke intake and exhaust control system is used to control the opening of the smoke inlet and the closing of the smoke exhaust outlet when the compression chamber is intake, and to control the closing of the smoke inlet and the opening of the smoke exhaust outlet when the compression chamber is exhaust.

[0017] A further provision provides a specific mechanism for a smoke intake and exhaust control system, the smoke intake and exhaust control system comprising:

[0018] Multiple valve groups: Each flue gas inlet and each flue gas outlet of the flue gas compression system is equipped with a valve group;

[0019] The valve actuating shaft has cams that correspond one-to-one with the valve group. The valve actuating shaft is connected to the rotating crankshaft. The valve actuating shaft is used to control the opening and closing of each smoke inlet and exhaust port through the cooperation of each cam with the valve group during its rotation.

[0020] Furthermore, in order to recover waste heat, the exhaust port is connected to the multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline through the exhaust manifold. The exhaust manifold is equipped with a molten salt waste heat recovery device, which is used to collect the heat generated during the compression process.

[0021] Furthermore, in order to heat the flue gas after gas-liquid separation to dry the residual liquid droplets entrained in the gas, the molten salt waste heat recovery unit is also used to heat the gas discharged from the gas outlet of the liquid collector.

[0022] Furthermore, a specific structure for a multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline with good acceleration and gas-liquid separation effects is provided. The multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline includes at least two tapered sections, a straight pipe section, and a flared section arranged along the fluid flow direction. Each tapered section includes a straight pipe guide section and a constriction section arranged sequentially along the fluid flow direction.

[0023] Furthermore, to facilitate the discharge of liquid from the liquid collector, a liquid outlet is provided at the bottom of the liquid collector.

[0024] This invention also relates to a demisting method for a supersonic gas-liquid separation energy-saving demisting device, the method comprising:

[0025] The flue gas after wet desulfurization and denitrification is pressurized by the pressurized flue gas inlet system and then enters the flue gas compression system;

[0026] The flue gas compression system, in conjunction with the flue gas inlet and outlet control system, pressurizes the flue gas, enabling it to enter the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipeline at a faster speed and greater pressure.

[0027] The multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline first pressurizes the flue gas step by step until it reaches supersonic speed, and then achieves gas-liquid separation at the end of its Laval nozzle.

[0028] The liquid collector collects the liquid separated from the end of the gas-liquid separation pipe of the multi-stage tapered coupling Laval nozzle, and the flue gas after the liquid is separated is discharged from the gas outlet at the top of the liquid collector.

[0029] By adopting the above technical solution, the present invention utilizes the difference in compressibility between liquid and gas in flue gas at supersonic speeds to achieve complete gas-liquid separation. Compared with traditional corrugated plate demisters, it has a great advantage in separation efficiency. Furthermore, the device requires less power source, is highly economical, has strong structural reliability, and is suitable for flue gas demisting treatment of various scales. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the supersonic gas-liquid separation energy-saving demisting device of the present invention;

[0031] Figure 2 for Figure 1 Top view;

[0032] Figure 3 This is a schematic diagram of the flue gas compression system and the flue gas intake and exhaust control system of the present invention;

[0033] Figure 4 This is a schematic diagram of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline of the present invention;

[0034] In the diagram, 1. Pressurized flue gas system; 11. Flue gas duct; 12. Flue gas fan; 2. Flue gas compression system; 21. Flue gas inlet; 22. Flue gas outlet; 23. Compression chamber; 24. Compressor plate; 25. Rotating crank; 26. Connecting rod; 27. Motor; 3. Multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline; 31. Tapered section; 311. Straight pipe guide section; 312. Closing section; 32. Straight pipe section; 33. Flaring section; 4. Flue gas intake and exhaust control system; 41. Valve assembly; 42. Valve starter shaft; 421. Cam; 5. Liquid collector; 6. Flue gas main pipe; 7. Molten salt waste heat recovery unit. Detailed Implementation

[0035] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0036] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a supersonic gas-liquid separation energy-saving demisting device includes:

[0037] Pressurized smoke inlet system 1;

[0038] The flue gas compression system 2 has its flue gas inlet 21 connected to the pressurized flue gas inlet system 1;

[0039] The multi-stage tapered coupling Laval nozzle gas-liquid separation pipe 3 is connected to the exhaust port 22 of the flue gas compression system 2, and is used to accelerate the flue gas entering it to supersonic speed so that the flue gas achieves gas-liquid separation at the end of its Laval nozzle.

[0040] The smoke inlet and exhaust control system 4 is used to control the corresponding smoke inlet 21 and smoke outlet 22 of the flue gas compression system 2 to open alternately;

[0041] The liquid collector 5 has its side wall connected to the outlet of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe 3, and has a gas outlet at the top and a liquid outlet at the bottom.

[0042] The demisting method of this type of supersonic gas-liquid separation energy-saving demisting device is as follows:

[0043] The flue gas after wet desulfurization and denitrification is pressurized by the pressurized flue gas inlet system 1 and then enters the flue gas compression system 2;

[0044] The flue gas compression system 2, in cooperation with the flue gas inlet and outlet control system 4, pressurizes the flue gas, so that the flue gas enters the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipeline 3 at a faster speed and greater pressure.

[0045] The multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipeline 3 first pressurizes the flue gas step by step until it reaches supersonic speed, and then achieves gas-liquid separation at the end of its Laval nozzle, i.e., the flared section 33.

[0046] The liquid collector 5 collects the liquid separated from the end of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe 3, and the flue gas after the liquid is separated is discharged from the gas outlet at the top of the liquid collector 5.

[0047] Specifically, the pressurized flue gas inlet system 1 ensures a continuous and large volume of flue gas intake for the entire device. The flue gas compression system 2 pressurizes the flue gas, ensuring that the flue gas entering the multi-stage converging coupled Laval nozzle gas-liquid separation pipe 3 has a high initial velocity and pressure, enabling the flue gas to be accelerated to supersonic speeds. The flue gas accelerates to supersonic speeds as it flows through the multi-stage converging sections of the multi-stage converging coupled Laval nozzle gas-liquid separation pipe 3. As it flows through the final flaring section, the gas in the flue gas continues to accelerate, while the liquid in the flue gas decelerates, achieving separation through the velocity difference. This embodiment utilizes the difference in compressibility between liquid and gas in the flue gas at supersonic speeds to achieve complete gas-liquid separation. Compared with traditional corrugated plate demisters, it has a significant advantage in separation efficiency, high economic efficiency, and strong structural reliability, making it suitable for flue gas demisting treatment of various scales.

[0048] In one embodiment, such as Figure 1 , Figure 2 As shown, the pressurized smoke inlet system 1 includes a smoke inlet duct 11 and a smoke inlet fan 12, with the smoke inlet fan 12 disposed within the smoke inlet duct 11.

[0049] In one embodiment, such as Figure 2 and Figure 3 As shown, the flue gas compression system 2 includes:

[0050] An even number of compression chambers 23 are divided into two groups. Each compression chamber 23 has a smoke exhaust port 22 and a smoke inlet port 21, and is equipped with a pressure plate 24.

[0051] The crankshaft connecting rod mechanism includes a rotating crank 25 and connecting rods 26 corresponding to the compression chambers 23. One end of the connecting rod 26 is hinged to the air compressor plate 24, and the other end is rotatably connected to the rotating crank 25 through a bearing. During the rotation of the rotating crank 25, the air compressor plate 24 is driven to slide through the connecting rods 26, so that the two sets of compression chambers 23 are always in a state of one set of air intake and one set of compression.

[0052] Motor 27 is connected to crank 25 to drive crank 25 to rotate; wherein,

[0053] The crank 25 is also connected to the impeller of the smoke inlet fan 12 so as to drive the impeller to rotate during its rotation;

[0054] The intake and exhaust control system 4 is used to control the opening of the smoke inlet 21 and the closing of the exhaust outlet 22 when the compression chamber 23 is receiving air, and to control the closing of the smoke inlet 21 and the opening of the exhaust outlet 22 when the compression chamber 23 is venting air.

[0055] In this embodiment, as Figure 2 and Figure 3 As shown, there are four compression chambers 23, and the smoke inlet duct 11 of the pressurized smoke inlet system 1 is connected to the four smoke inlets 21 of the four compression chambers 23 through four manifolds respectively.

[0056] Specifically, when the crank 25 is driven to rotate, the crankshaft connecting rod mechanism converts the rotational motion of the crank 25 into the reciprocating linear motion of the connecting rod 26, which pushes the compressor plate 24 to move up and down. Each compression chamber 23 has two strokes: intake and compression. The working strokes of the two sets of compression chambers 23 are exactly opposite, thereby ensuring that the flue gas compression system 2 can continuously and uninterruptedly discharge high-temperature and high-pressure flue gas, thus ensuring the stable operation of the entire device.

[0057] In one embodiment, such as Figure 3 As shown, the smoke intake and exhaust control system 4 includes:

[0058] Multiple valve groups 41 are provided in each smoke inlet 21 and each smoke outlet 22 of the flue gas compression system 2;

[0059] The valve actuation shaft 42 has cams 421 that correspond one-to-one with the valve assembly 41. The valve actuation shaft 42 is connected to the rotating crank 25 for transmission. The valve actuation shaft 42 is used to control the opening and closing of each smoke inlet 21 and smoke outlet 22 through the cooperation of each cam 421 with the valve assembly 41 during its rotation.

[0060] In this embodiment, a timing pulley can be configured on the valve starter shaft 42 and the crank 25 respectively, and a timing belt can be fitted on both timing pulleys at the same time to realize the transmission connection between the valve starter shaft 42 and the crank 25.

[0061] In one embodiment, such as Figure 1 and Figure 2 As shown, each exhaust port 22 is connected to the exhaust manifold 6 via a branch pipe. The exhaust manifold 6 is connected to the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe 3. The exhaust manifold 6 is equipped with a molten salt waste heat recovery device 7. The molten salt waste heat recovery device 7 is used to collect the heat generated during the compression process. The molten salt waste heat recovery device 7 is also used to heat the gas discharged from the gas outlet of the liquid collector 5.

[0062] Specifically, the high-temperature, high-pressure, high-speed compressed flue gas enters the molten salt waste heat recovery unit 7 through the exhaust manifold 6, where it exchanges heat with the molten salt. The gas then enters the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipe 3 through the outlet of the exhaust manifold 6. The molten salt waste heat recovery unit 7 collects the heat generated during the compression process and heats the gas discharged from the gas outlet of the liquid collector 5 to dry the residual liquid droplets entrained in the gas, thereby achieving further removal of liquid droplets from the flue gas.

[0063] In one embodiment, such as Figure 1 , Figure 2 and Figure 4 As shown, the multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline 3 includes at least two tapered sections 31, a straight pipe section 32, and a flared section 33 arranged along the fluid flow direction. Each tapered section 31 includes a straight pipe guide section 311 and a constriction section 312 arranged sequentially along the fluid flow direction.

[0064] Considering that traditional single-cone contraction leads to a larger Reynolds coefficient and mutual interference of fluid flows within the pipe, in simpler terms, some fluid flows will oppose their own flow, increasing turbulence and hindering fluid acceleration. This embodiment employs at least two stages of tapering sections 31 to achieve gradual contraction, effectively solving this problem. Furthermore, the straight pipe section 32 in this embodiment acts as an "energy accumulation zone," increasing the degree of fluid congestion. This allows the gas to be accelerated to supersonic speeds at the flared section 33 at the rear end of the Laval pipe.

[0065] The principle of gas-liquid separation in the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipe 3 is as follows: When high-speed, high-pressure flue gas flows out of the exhaust manifold 6, it has an extremely high velocity. After passing through the various reduction sections of the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipe 3, the flow velocity increases, and the flow velocity approaches one Mach number. At this time, the gas in the flue gas becomes a compressible fluid. When the gas in the flue gas flows through the flared section 33, it accelerates to a speed of over Mach 1, reaching supersonic speed. The liquid in the flue gas is affected by incompressibility and decelerates when flowing through the flared section 33. The velocity difference forces the gas in the flue gas to completely separate from the liquid droplets. The liquid impacts the wall of the liquid collector 5, flows downward under the action of gravity, and collects in the liquid collector 5. The gas part flows out through the gas outlet at the top of the liquid collector 5.

[0066] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A supersonic gas-liquid separation energy-saving demisting device, characterized in that, include: Pressurized smoke inlet system (1); The flue gas compression system (2) has its flue gas inlet (21) connected to the pressurized flue gas inlet system (1); A multi-stage tapered coupling Laval nozzle gas-liquid separation pipe (3) is connected to the exhaust port (22) of the flue gas compression system (2) to accelerate the flue gas entering it to supersonic speed so that the flue gas achieves gas-liquid separation at the end of its Laval nozzle; The smoke inlet and outlet control system (4) is used to control the corresponding smoke inlet (21) and smoke outlet (22) of the flue gas compression system (2) to open alternately; The liquid collector (5) has its side wall connected to the outlet of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe (3), and a gas outlet is provided at the top. The flue gas compression system (2) includes: An even number of compression chambers (23) are divided into two groups. Each compression chamber (23) has the exhaust port (22) and the inlet port (21), and is slidably fitted with a pressure plate (24). The crankshaft connecting rod mechanism includes a rotating crank (25) and connecting rods (26) corresponding to the compression chambers (23). One end of the connecting rod (26) is hinged to the air compressor plate (24), and the other end is rotatably connected to the rotating crank (25). During the rotation of the rotating crank (25), the air compressor plate (24) is driven to slide through the connecting rods (26), so that the two sets of compression chambers (23) are always in a state of one set of air intake and one set of compression. The motor (27) is connected to the rotating crank (25) to drive the rotating crank (25) to rotate; wherein, The crank (25) is also connected to the impeller of the smoke inlet fan (12) to drive the impeller to rotate during its rotation; The intake and exhaust control system (4) is used to control the opening of the intake port (21) and the closing of the exhaust port (22) when the compression chamber (23) is filled with air, and to control the closing of the intake port (21) and the opening of the exhaust port (22) when the compression chamber (23) is filled with air. The smoke intake and exhaust control system (4) includes: Multiple valve groups (41), each smoke inlet (21) and each smoke outlet (22) of the flue gas compression system (2) is equipped with a valve group (41); The valve starter shaft (42) has cams (421) that correspond one-to-one with the valve group (41). The valve starter shaft (42) is connected to the rotating crank (25) for transmission. The valve starter shaft (42) is used to control the opening and closing of each smoke inlet (21) and smoke outlet (22) through the cooperation of each cam (421) with the valve group (41) during its rotation. The multi-stage tapered coupling Laval nozzle gas-liquid separation pipeline (3) includes at least two tapered sections (31), straight pipe sections (32) and flared sections (33) arranged along the fluid flow direction. Each tapered section (31) includes a straight pipe guide section (311) and a constriction section (312) arranged sequentially along the fluid flow direction.

2. The supersonic gas-liquid separation energy-saving demisting device according to claim 1, characterized in that, The pressurized smoke inlet system (1) includes a smoke inlet duct (11) and a smoke inlet fan (12), wherein the smoke inlet fan (12) is disposed in the smoke inlet duct (11).

3. The supersonic gas-liquid separation energy-saving demisting device according to claim 1, characterized in that, The exhaust port (22) is connected to the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe (3) through the exhaust manifold (6). The exhaust manifold (6) is equipped with a molten salt waste heat recovery device (7), which is used to collect the heat generated during the compression process.

4. The supersonic gas-liquid separation energy-saving demisting device according to claim 3, characterized in that, The molten salt waste heat recovery unit (7) is also used to heat the gas discharged through the gas outlet of the collector (5).

5. The supersonic gas-liquid separation energy-saving demisting device according to claim 1, characterized in that, The liquid collector (5) has a liquid outlet at its bottom.

6. A demisting method for a supersonic gas-liquid separation energy-saving demisting device as described in any one of claims 1-5, characterized in that, The methods include: After wet desulfurization and denitrification, the flue gas is pressurized by the pressurized flue gas inlet system (1) and then enters the flue gas compression system (2); The flue gas compression system (2) pressurizes the flue gas in cooperation with the flue gas inlet and outlet control system (4), so that the flue gas enters the multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipeline (3) at a faster speed and greater pressure. The multi-stage gradually converging coupled Laval nozzle gas-liquid separation pipeline (3) first pressurizes the flue gas step by step to supersonic speed, and then achieves gas-liquid separation at the end of its Laval nozzle; The liquid collector (5) collects the liquid separated from the end of the multi-stage tapered coupling Laval nozzle gas-liquid separation pipe (3), and the flue gas after the liquid is separated is discharged from the gas outlet at the top of the liquid collector (5).

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