CN117085417A - Coiled pipe type separator - Google Patents

Abstract

The invention discloses a coil type separator. The separator includes a cylinder. An air inlet is provided on the side wall of the lower end of the cylinder. The upper end of the cylinder has an upper inclined cone, the lower end has a lower inclined cone, and the side wall of the lower inclined cone. A water level sensor is provided. There is a drainage pipe at the bottom of the lower inclined cone. A valve is installed on the drainage pipe. Two sets of spiral coils are fixedly installed in the cylinder. The cylinder is located above the air inlet and is installed below the spiral coil. The guide impeller blade; spiral coil lift angle optimization method includes establishing a simplified three-dimensional model, setting corresponding parameters, analyzing the results and comparing them, and then obtaining the optimal lift angle. In the case of small changes in pressure loss, the area of the low-speed area of the swirl section generated by the guide impeller is reduced as much as possible to improve the separation effect.

Description

A coil type separator

Technical field

The invention relates to cyclone separation technology, and relates to a coil separator.

Background technique

The wet ammonia flue gas desulfurization process uses ammonia as an absorbent to remove SO2 in the flue gas, and the separator is an important part of it. Under the dual action of vibration force and hot air flow through the air distribution plate, the material in the coil separator is suspended in contact with the hot air flow. There is intense turbulence between the material particles and the heat medium, which reduces the heat transfer. And the mass transfer process is strengthened. The dried product is discharged from the discharge port. After the evaporated water and waste gas are recovered by the separator, the purified flue gas is discharged to the desulfurization tower through the induced draft fan. Therefore, the separation efficiency of the separator determines economic benefits and production safety issues.

Vertical separator is the most common type of coil separator. This type of separator has the characteristics of simple structure and reliable operation. It mainly uses the principle of gravity sedimentation to achieve multi-phase separation through a guide impeller. A guide impeller is installed inside the cylinder to force the mixture fluid to pass through according to the prescribed path. Under the action of the impeller blades, the mixture fluid enters the swirl section and spirals up. In the swirl section, the particles collide with each other and contact the cylinder wall, and the gas exits from the outlet. The air port leaves and enters the induced draft fan, and the powder and fly ash are collected with the droplets to the drainage port for subsequent recycling, finally achieving separation.

The structure of the guide impeller determines the separation efficiency. The more reasonable the structural parameters, the better the separation effect. However, there is a low-pressure reflux effect at the inner cylinder of the guide impeller. The small droplets have high follow-up and can easily move to the center with the gas. Leaving directly from the air outlet, it cannot contact the inner wall of the cylinder, resulting in insufficient collision, thus affecting the separation of the mixture, reducing economic benefits, and causing safety hazards.

Contents of the invention

The present invention designs a coil-type separator to obtain the optimal lifting angle.

The technical solution disclosed by the present invention is as follows: a coiled tube separator, including a spiral coiled tube separator. The spiral coiled tube separator includes a cylinder body, an air inlet is provided on the side wall of the lower end of the cylinder body, and an air inlet is provided on the upper end of the cylinder body. There is an upper inclined cone and a lower inclined cone at the lower end. The side wall of the lower inclined cone is equipped with a water level sensor. The bottom of the lower inclined cone has a drainage pipe. A valve is installed on the drainage pipe. Two sets of spiral coils are fixedly installed in the cylinder.

Among them, the starting point of the first group of spiral coils is 0°, and the starting point of the first group of spiral coils is 180°. At the same level, they rotate right to form a double helix structure, and the top closed loop forms a single closed loop double helix coil.

On the basis of the above solution, as a preferred option, the angle between the upper inclined cone and the horizontal plane is 45°, there is an air outlet in the middle, and the structure of the lower inclined cone and the upper inclined cone are symmetrical.

Based on the above solution, preferably, a guide impeller blade is installed in the cylinder above the air inlet and below the spiral coil.

On the basis of the above solution, as a preference, the total height of the guide impeller blades is 140mm, the radius of the inner cylinder is 150mm, the radius of the impeller is 390mm, the blade inclination angle of the guide impeller is 37°, the number of blades is 24 and counterclockwise Evenly distributed on the cylinder.

On the basis of the above solution, as a preferred method, the single closed-loop double spiral coil assembly steps are as follows: Insert the single closed-loop double spiral coil into the cylinder, with one end of the closed loop facing up, one end of the open loop facing down, and a small section above the air inlet. distance, the coil and the cylinder are then fixed by welding, and then the beveled cone parts of the upper air outlet and lower outlet are installed. The welding is all done by arc welding.

Based on the above solution, as a preferred option, the material and cylinder of the single closed-loop double spiral coil are stainless steel S31603.

Based on the above scheme, as a preferred method, the simulation analysis method is:

Use the helix and scanning in the SolidWorks software to draw the single closed-loop double spiral coil, then combine the cylinder with the single closed-loop double spiral coil and import it into the Fluent software. On the air inlet of the single closed-loop double spiral coil, The air outlet and lower outlet are closed;

Mesh the single closed-loop double spiral coil, set the element size, and mesh by default. Next, set the boundary layer of the single closed-loop double spiral coil, and name the inlet and outlet and pipe wall boundaries;

Solving process:

Open the Setup plug-in in Fluent, check whether the grid is wrong in General, and change the size ratio to mm;

Set the gravity to 9.81m/s2 in general and the turbulence model to the standard k-epsilon RNG model in the model;

Create a jet source, the jet source type is surface, the material is ash-solid, and the air inlet flow rate is 10m/s;

Copy the database material, select water-liquid as the fluid material, the medium density ρ is 998.2kg/m3, and the dynamic viscosity μ is 0.1kg/(m.s);

Set the boundary conditions, set the flow velocity at the inlet to 10m/s, and select reflect for the discrete phase BC type;

Select simple as the solution solution, standard initialization as the initialization method, and select the air inlet as the calculation reference;

Complete the initialization and perform operational calculations. Set the number of iterations to 1000. After the iteration reaches stability, complete the solution calculation;

Through the CFD post module, the influence of the particle residence state and movement trajectory of the fluid and particles in the cylinder on the dust removal effect is obtained through the solution function image and animation.

Compared with the prior art, the present invention has the following beneficial effects:

The RNG k-epsilon model is reasonable: the separator takes in air from a tangential direction, and the cylinder is mainly cylindrical, so the cylinder is mainly dominated by swirling flow, with many rotations. The RNG k-epsilon model is better than the standard k-epsilon simulation. Better, such as shear flow, vortex and separation flow, and swirl correction.

The algorithm is suitable: The core idea of the SIMPLE algorithm is to use "guess first and then correct" to solve the corresponding analysis parameters in the corresponding grid area, which is suitable for the design optimization concept of the present invention.

Reasonable selection of coil parameters: The coil parameters consider the effect of the coil on the guide impeller, so the structural parameters of the coil are selected for optimization, including coil elevation angle, coil diameter, and coil height. Since changes in coil diameter can easily affect installation and helical position, resulting in increased variables and greater error, we chose to compare the effects of coils with different rise angles under the conditions of fixed coil height and fixed coil diameter.

The selection of the range of the rise angle is more reasonable: Since the tangent function changes very quickly, each increase in the rise angle will cause the coil pitch difference to become larger and larger. Therefore, the pitch difference of the coils with different rise angles is not fixed. In order to minimize It is possible to control the change of the variable, so the elevation angle is selected between 8° and 12°.

The structure is simple and practical. By installing a spiral coil inside the cylinder to guide the flow of air, the overall flow rate of the gas mixture is increased by about 3m/s on the original basis. In addition, it can be seen from Figure 6 that the movement streamline trajectory has increased And most of the particles can move to the inner wall of the cylinder, which means that the contact time between the mixture and the wall surface is increased to increase the number of collisions, making the dust removal effect better and more efficient, greatly improving the quality of dust removal, reducing the need for equipment, and reducing costs.

The addition of a single closed-loop double spiral coil in the swirl section of the cylinder has a diversion effect on the fluid, allowing the gas to spiral upward, making up for the energy lost in pressure, and saving energy while the separation efficiency remains unchanged.

The single closed-loop double spiral coil has a right-handed structure, which is consistent with the rotation direction of the impeller blades. The spiral airflow coming out of the impeller is more susceptible to the diversion effect of the coil and contacts with the coil for heat exchange. The condensed dust-containing droplets can It falls along the coil, collects on the support plate of the guide impeller, and finally flows to the reservoir through the pipe opening, which improves the separation efficiency.

The addition of single closed-loop double spiral coils increases the contact area of the inner wall of the cylinder, changes the flow field to make the fluid flow more fully, increases the fluid speed, and further increases the number of collisions of dust particles and the duration of contact with the cylinder wall.

Description of the drawings

Figure 1 is a schematic structural diagram of the spiral coil separator barrel;

Figure 2 is a half-section view of the spiral coil separator;

Figure 3 is a diagram of the guide impeller;

Figure 4 is a schematic diagram of a single closed-loop double spiral coil;

Figure 5 is the speed cloud diagram of coils with different elevation angles;

Figure 6 is the pressure cloud diagram of coils with different elevation angles.

Detailed ways

In order to explain the embodiments of the present invention or technical solutions in the prior art more clearly, the specific implementation modes of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without exerting creative efforts, other drawings can also be obtained based on these drawings, and obtain Other embodiments.

As shown in Figure 1-6, a coil separator includes a spiral coil separator. The spiral coil separator includes a cylinder 4. The height of the cylinder 4 is 8000mm, and the height of the swirl section is 5600mm. An air inlet 1 with a radius of 315mm is added to the surface of the cylinder. The air inlet is connected to the Venturi tube through a flange, receives the processed water vapor and dust, and transports it to the inside of the cylinder for separation.

The upper end of the cylinder is provided with an upward inclined cone 5, and the side wall of the upper inclined cone is provided with lifting lugs 10. The lifting lugs are welded by arc welding. When installing the drainage pipe, you need to lift the separator to the skirt through lifting lugs, then set a nozzle from the side of the skirt to put the drainage pipe in and finally weld it to the separator. The upper inclined cone has a flange for connecting the induced draft fan, and the separated gas will be transported from the outlet to the desulfurization tower. The angle between the upper inclined cone and the horizontal plane is 75°, and there is an air outlet in the middle. The horizontal height of the upper inclined cone is 1000mm. The lower end has a lower inclined cone, and the angle between the lower inclined cone and the horizontal is 45°. There is a water outlet in the middle, and the side is connected to the pipe. The horizontal height of the lower inclined cone is 600mm.

The lower oblique vertebra forms a reservoir and is connected to a valve 2 through a drainage pipe. A water level sensor 3 is provided on the lower vertebra to control the opening and closing of the valve.

A spiral coil 7 is added to the cylinder. The single closed-loop spiral coil is composed of two sets of coils with the same size and structure, and the diameter is 25mm, totaling 3266mm. The wave height A of the coil is 1180mm, and the tube wall thickness is 10mm. The starting point of the first group is 0°, and the starting point of the second group is 180°, both at the same level. The right-hand rotation forms a double helix structure, and a closed loop is formed at the top to prevent the condensed dust-containing droplets from being thrown out of the outlet with inertia.

A guide impeller blade is installed in the cylinder above the air inlet and 50mm below the spiral coil.

The welding base of the guide impeller blade is the guide impeller inner cylinder 6, the total height of the impeller is 140mm, the inner diameter cylinder radius is 150mm, the impeller radius is 390mm, the blade inclination angle of the guide impeller is 37°, the number of blades is 24 and counterclockwise Evenly distributed on the inner cylinder.

There is a nozzle A9 connected to the side of the cylinder. Nozzle A is connected to nozzle B8 on the lower inclined cone, and nozzle A is connected to nozzle B. Nozzle A is installed horizontally, and nozzle B is installed horizontally with an inclination of 45°, so as to facilitate the accumulation of water in the The dust-containing droplets on the inner cylinder of the guide impeller are transferred to the drain outlet.

Working principle: The mixture of water vapor and exhaust gas enters from the air inlet 1 in the form of mist, and enters the inside of the cylinder tangentially against the side of the cylinder. Due to the water level sensor 3 and valve 2, the height of the liquid level is controlled, and part of the mixture enters the storage tank. The rest of the mixture can only pass through the guide impeller 6 and then leave from the air outlet 5. Under normal working conditions, the liquid level in the separation cylinder should be kept below the inlet to avoid gas phase entrainment of droplets when the gas flows through the lower liquid phase zone. On the way out, the diversion effect of the spiral coil increases the collision and wall contact time of the mixture, and then settles by gravity, thereby improving the dust removal effect. Finally, the closed loop at the top of the coil is used to trap some of the lower mass mixture that is thrown out by inertia.

Assembly steps of single-closed-loop double-spiral coil: Insert the single-closed-loop double-spiral coil into the cylinder, with the closed-loop end up and the open-loop end down, a short distance above the air inlet. The coil and cylinder are then welded To achieve fixation, the guide impeller is fixed to the cylinder under the coil by welding, and finally the beveled cone parts of the upper air outlet and the lower outlet are installed. The material and cylinder of the single closed-loop double spiral coil are stainless steel S31603.

In order to reduce the low-speed area of the swirl section generated by the guide impeller as much as possible under the condition of small pressure loss changes, a spiral coil rise angle optimization method was designed.

(1) Establish five simplified three-dimensional models with coil rise angles of 8°, 9°, 10°, 11°, and 12° respectively;

(2) Extract the volume and mesh the simplified model in ANSYS Workbench,

Open the Setup plug-in in Fluent, check whether the mesh is wrong in General, and modify the size scale to mm; set the gravity to 9.81m/s2 in General, and set the turbulence model in the model to the standard k-epsilon RNG model;

(3) Create the injection source, select the air inlet, the injection source type is surface, the material is ash-solid, the solid particle diameter is 20 μm, and the air inlet flow rate is 10m/s;

(4) Copy the database material, select water-liquid as the fluid material, the medium density ρ is 998.2kg/m3, and the dynamic viscosity μ is 0.1kg/(m.s);

(5) Boundary conditions: The air outlet and water outlet are set to escape;

(6)Algorithm selection SIMPLE;

(7) Complete the initialization and perform operational calculations. Set the number of iterations to 1000. After the iteration reaches stability, complete the solution calculation;

(8) Analyze the calculation results of the above five simplified models through the CFD post module, including the analysis of the low-speed area of the swirl section, the maximum flow rate of particles, and the overall internal flow field pressure;

(9) Compare the analysis results in step 8 to obtain the optimal elevation angle.

Specifically, the velocity field distribution inside the coil separator with different lift angles is shown in Figure 5, and the pressure field distribution is shown in Figure 6. The order in the figure is from left to right according to the lift angle, with the leftmost one having a lift angle of 8°. Coil-type separator, the one on the far right is a coil-type separator with a lifting angle of 12°.

Taking the coil separator with a lift angle of 10° as an example, comparing it with other flow fields, the velocity field distribution is shown in the third picture in Figure 5, and the pressure field distribution is shown in the third picture in Figure 6. It shows that the maximum flow velocity is located at the air inlet position and the left side of the upper end of the guide impeller. The maximum particle flow velocity is 20.6m/s, and there is a conical low-pressure return zone in the center.

Simulation analysis of a coil separator with a lift angle of 8° is performed. The velocity field distribution is shown in the first picture in Figure 5, and the pressure field distribution is shown in the first picture in Figure 6. They are different from those of the existing separator. Comparing the internal flow field, the flow velocity distribution is similar, with a maximum flow velocity of 22.5m/s, but the low-speed area in the center is significantly reduced, and the pressure drops significantly.

Simulation analysis of a coiled separator with a lift angle of 9° is performed. The velocity field distribution is shown in the second picture in Figure 5, and the pressure field distribution is shown in the second picture in Figure 6. Compared with the existing separator Comparing the internal flow field, the flow velocity distribution is similar, the maximum flow velocity is 21.6m/s, the low-speed area in the center is slightly reduced, and the pressure drops slightly.

Simulation analysis of a coil separator with a lift angle of 11° is performed. The velocity field distribution is shown in the fourth picture in Figure 5, and the pressure field distribution is shown in the fourth picture in Figure 6. They are different from those of the existing separator. Comparing the internal flow field, the flow velocity distribution is similar, with the maximum flow velocity being 21.7m/s, but the velocity area at the center increases slightly and the pressure decreases slightly.

Simulation analysis of a coil separator with a lift angle of 12° is performed. The velocity field distribution is shown in the fifth picture in Figure 5, and the pressure field distribution is shown in the fifth picture in Figure 6. They are different from those of the existing separator. Comparing the internal flow field, the flow velocity distribution is similar, the maximum flow velocity is 21.7m/s, the low-speed area in the center shrinks but extends upward, and the pressure rises slightly.

As shown in Figure 5, the velocity cloud diagram in the flow field of the coil separator with different lift angles. Looking from right to left, the conical low-pressure reflux zone caused by the guide impeller gradually moves downward as the lift angle decreases. Gather.

As shown in Figure 6, the pressure cloud diagram in the flow field of coil separators with different lifting angles. Looking from left to right, the pressure cloud diagram at an 8° lifting angle changes greatly, and the value drops to half of the pressure of other separators. Overall The pressure change trend will increase with the increase of the lifting angle.

It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A coil-type separator, characterized in that the coil-type separator includes a cylinder, an air inlet is provided on the side wall of the lower end of the cylinder, the upper end of the cylinder has an upper inclined cone, the lower end has a lower inclined cone, and the lower end of the cylinder has an upper inclined cone. The side wall of the inclined cone is equipped with a water level sensor, and the bottom of the lower inclined cone is equipped with a drainage pipe. A valve is installed on the drainage pipe, and two sets of spiral coils are fixedly installed in the cylinder. Among them, the starting point of the first group of spiral coils is 0°, and the starting point of the first group of spiral coils is 180°. At the same level, they rotate right to form a double helix structure, and the top closed loop forms a single closed loop double spiral coil. A guide impeller blade is installed in the cylinder above the air inlet and below the spiral coil; Spiral coil rise angle optimization method, (1) Establish five simplified three-dimensional models with coil rise angles of 8°, 9°, 10°, 11°, and 12° respectively; (2) Extract the volume and mesh the simplified model in ANSYS Workbench, Open the Setup plug-in in Fluent, check whether the mesh is wrong in General, and modify the size scale to mm; set the gravity to 9.81m/s2 in General, and set the turbulence model in the model to the standard k-epsilon RNG model; (3) Create the injection source, select the air inlet, the injection source type is surface, the material is ash-solid, the solid particle diameter is 20 μm, and the air inlet flow rate is 10m/s; (4) Copy the database material, select water-liquid as the fluid material, the medium density ρ is 998.2kg/m3, and the dynamic viscosity μ is 0.1kg/(m.s); (5) Boundary conditions: The air outlet and water outlet are set to escape; (6)Algorithm selection SIMPLE; (7) Complete the initialization and perform operational calculations. Set the number of iterations to 1000. After the iteration reaches stability, complete the solution calculation; (8) Analyze the calculation results of the above five simplified models through the CFD post module, including the analysis of the low-speed area of the swirl section, the maximum flow rate of particles, and the overall internal flow field pressure; (9) Compare the analysis results in step 8 to obtain the optimal elevation angle. 2. A coil separator as claimed in claim 1, characterized in that: The RNG k-epsilon model transport equation is: In the formula, C _1ε =1.42C _2ε =1.68C _μ =0.0845 G _k represents the generation of turbulent kinetic energy caused by the mean velocity gradient G _b is the turbulent kinetic energy generated by buoyancy Y _M represents the contribution of fluctuating expansion to the total dissipation rate in compressible turbulent flow ρfluid density εDissipation rate of turbulent pulsation kinetic energy α _k and α _ε are the reciprocals of the effective Prandtl numbers of k and ε respectively. S _k and S _ε are user-defined source terms. 3. A coil type separator as claimed in claim 1, characterized in that the angle between the upper inclined cone and the horizontal plane is 75°, and the middle part has an air outlet, and the angle between the lower inclined cone and the horizontal plane is 45°, and the middle part has an air outlet. The water outlet is connected to the pipe on the side. 4. A coil separator according to claim 1, characterized in that a guide impeller blade is installed in the cylinder above the air inlet and 50 mm below the spiral coil. 5. A coil type separator as claimed in claim 3, characterized in that the total height of the guide impeller blades is 140mm, the radius of the inner cylinder is 150mm, the radius of the impeller is 390mm, and the blade inclination angle of the guide impeller is 140mm. is 37°, and the number of blades is 24 and evenly distributed counterclockwise on the inner cylinder of the impeller. 6. A coil type separator as claimed in claim 1, characterized in that the single closed loop double spiral coil assembly step is: insert the single closed loop double spiral coil into the barrel, with one end of the closed loop on top and one end of the open loop. Facing downward and a short distance above the air inlet, the coil and the cylinder are then fixed by welding, and then the beveled cone parts of the upper air outlet and the lower outlet are installed. 7. A coil-type separator according to claim 1, characterized in that the material of the single closed-loop double spiral coil and the cylinder are stainless steel S31603.