Inorganic salt crystal slurry thickening system capable of efficiently separating organic matters

Abstract

According to the inorganic salt crystal slurry thickening system capable of efficiently separating the organic matters, the oil skimming groove is formed in the settling section at the upper part of the thickener, so that the organic matters floating on the surface of a water phase are discharged by utilizing density difference, the organic matters are prevented from being attached to the surfaces of crystals, and the interference of the organic matters on a crystallization process is reduced; and the problem of equipment blockage possibly caused by accumulation of organic matters is also avoided. Meanwhile, a low-speed feeding technology is adopted in the primary pulp distributor, disturbance during feeding is greatly reduced, the completeness of crystals can be maintained, the quality of the final crystals is ensured, in addition, a water phase discharged from the bottom of the oil skimming tank is guided into the thickener again through a special water phase return pipeline, and the water phase is recycled. The circulation process enables contained fine crystal grains to serve as crystal nucleuses to continue to participate in crystallization, the crystallization speed is increased, the crystallization efficiency is greatly improved, and efficient utilization of resources and optimization of the process are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of crystallization separation, and in particular relates to an inorganic salt slurry thickening system for efficiently separating organic matter. Background Art

[0002] The treatment of highly concentrated brine containing organic matter has always been a bottleneck and difficulty in the field of water treatment, especially the highly concentrated brine produced at the tail end of the water treatment device of chemical and coal chemical enterprises. Its characteristics are not only the extremely high salt content, but also the large amount of organic matter that is difficult to degrade, and the salt components are complex and diverse. At present, the commonly used treatment method is the concentration and crystallization salt separation, which aims to recycle the salt and organic matter in it.

[0003] Although the concentration and crystallization separation technology is regarded as a green and environmentally friendly technology for purifying high-salinity wastewater, it has encountered many difficulties in the process of promoting industrial application. The main problem lies in the presence of refractory organic matter, which not only affects the long-term stable operation of the crystallization separation device, but also easily leads to equipment blockage, which in turn causes the problem of low purity of the output salt. In particular, the thickener is prone to blockage, which occurs frequently and requires frequent maintenance, becoming a major problem in the treatment of high-concentration brine. Therefore, how to effectively solve the impact of refractory organic matter on the treatment of high-concentration brine and improve salt purity and equipment operation efficiency has become a key point that urgently needs to be broken through in the current water treatment field. Summary of the invention

[0004] In view of the problems such as blockage of thickener equipment, reduced processing efficiency and decreased purity of output salt caused by the presence of difficult-to-degrade organic matter, the present invention provides an inorganic salt slurry thickening system for efficiently separating organic matter. The thickener provided by the present invention is provided with an oil skimmer in the upper sedimentation section to discharge organic matter floating on the water phase out of the thickener, thereby reducing the interference of organic matter on the crystallization process and avoiding adhesion to the crystal surface, while also avoiding blockage caused by organic matter. In addition, the present invention is also provided with a raw slurry distributor, which adopts a low-speed feeding method to minimize feeding disturbance, which is beneficial to maintaining the integrity of the crystal and ensuring the crystal quality. In addition, the water phase discharged from the bottom of the oil skimmer is returned to the thickener through the water phase return pipeline, and the fine crystals contained therein serve as crystal nuclei to continue the crystallization process, thereby accelerating the crystallization process and improving the crystallization efficiency.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An inorganic salt slurry thickening system for efficiently separating organic matter comprises: a thickener, a raw slurry distributor, an oil skimmer and a clarified mother liquor tank, wherein the interior of the thickener is divided into an upper sedimentation section and a lower thickening section; the top of the sedimentation section is open, and the raw slurry distributor is located in the sedimentation section and is used to uniformly distribute the raw slurry to be crystallized entering the sedimentation section; the oil skimmer is arranged at the top of the sedimentation section, an organic component discharge port is provided on the thickener shell corresponding to the upper part of the tank body of the oil skimmer, and an aqueous phase outlet is provided on the thickener shell corresponding to the lower part of the tank body of the oil skimmer; the clarified mother liquor tank is arranged at the upper part of the sedimentation section, and a mother liquor outlet is provided on the thickener shell corresponding to the lower part of the tank body of the clarified mother liquor tank; and an inorganic salt slurry discharge port is provided at the bottom of the thickening section.

[0007] In some embodiments, the sedimentation section and the thickening section both adopt a structure that is wide at the top and narrow at the bottom, including an upper cylindrical barrel section and a lower conical barrel section; the diameter ratio of the cylindrical barrel section of the sedimentation section to the cylindrical barrel section of the thickening section is (2-3):1; the cone angle of the conical barrel section of the sedimentation section is the same as that of the conical barrel section of the thickening section, both of which are 60° to 120°; the tangent height of the sedimentation section is 560m to 1500mm; the tangent height of the thickening section is 400m to 800mm.

[0008] In some embodiments, the puree distributor includes a side plate and a bottom plate, the side plate is connected to the bottom plate, and the side plate and the bottom plate together enclose a cavity for accommodating the puree, and a plurality of vertically penetrating small holes are evenly distributed on the bottom plate; the diameter of the small holes is 20 mm to 30 mm; the porosity of the bottom plate is 60% to 75%; the rate at which the puree passes through the small holes is 0.4 to 1.0 m / s.

[0009] In some embodiments, the vertical position of the clarified mother liquor tank is lower than the vertical position of the skimming tank, and the vertical distance between the top of the clarified mother liquor tank and the bottom of the skimming tank is 50 mm to 100 mm.

[0010] In some embodiments, the inorganic salt slurry thickening system also includes: a mother liquor output pipe connected to the mother liquor outlet, and the mother liquor output pipe is an inverted U-shape as a whole; along the vertical direction, the U-shaped top of the inverted U-shaped mother liquor output pipe is higher than the top of the skimming tank.

[0011] In some embodiments, the inorganic salt slurry thickening system further includes: an agitator, the agitator including a stirring blade and a stirring shaft, the stirring blade is provided at one end of the stirring shaft extending into the sedimentation section, and the stirring blade is located in the thickening section.

[0012] In some embodiments, the agitator further includes: a cleaning frame, the cleaning frame is provided on one end of the agitator shaft extending into the thick section, the cleaning frame is close to the inner wall of the thick section, and is 20 mm to 30 m away from the inner wall of the thick section.

[0013] In some embodiments, the inorganic salt slurry thickening system further includes: a slurry discharge pipe connected to the inorganic salt slurry discharge port, wherein the slurry discharge pipe is disposed obliquely upward and has an angle of 45° to 65° with the vertical direction.

[0014] In some embodiments, the inorganic salt slurry thickening system also includes: a controller and an oil-water interface meter and a density meter respectively connected to the controller; the oil-water interface meter is used to detect the height value of the oil-water interface in the sedimentation section; the density meter is used to detect the slurry concentration in the thickening section; the controller is connected to the valve control at the organic component discharge port to control the switch of the organic component discharge port according to the reading of the oil-water interface meter; the controller is connected to the valve control at the inorganic salt slurry discharge port to control the switch of the inorganic salt slurry discharge port according to the reading of the density meter.

[0015] In some embodiments, the thickener is further provided with an inspection port for maintenance.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The thickener provided by the present invention is provided with a skimmer at the top of the settling section to discharge the organic matter floating on the water phase, which can reduce the interference of the organic matter on the crystallization process, avoid adhesion to the crystal surface, ensure more uniform crystal growth, and improve the crystal quality;

[0018] 2. The skimmer provided by the present invention discharges organic components in time, which can maintain the stable operation of the thickener, avoid the blockage problem caused by difficult-to-degrade organic matter, and reduce the maintenance frequency and downtime;

[0019] 3. The water phase return pipeline provided by the present invention feeds the water phase containing fine crystals into the thickener. The fine crystals serve as crystal nuclei, which can promote the growth of new crystals, accelerate the crystallization process, improve the overall crystallization efficiency, help form uniform and regular crystals, and reduce the generation of irregular crystals and fine particles;

[0020] 4. The raw pulp distributor provided by the present invention adopts a low-speed feeding method, which can not only minimize the feeding disturbance, but also reduce the shear force on the crystals, reduce the risk of the crystals being damaged during the feeding process, and is conducive to maintaining the integrity and quality of the crystals. It also helps to maintain the stable state of the liquid phase in the thickener, reduce operating fluctuations, and improve the stability of the crystallization process;

[0021] 5. The agitator provided by the present invention is also provided with a cleaning frame to prevent crystals from agglomerating on the side wall, reduce the thickness of the sticky layer on the side wall, reduce the probability of crystal scars, avoid equipment failures caused by crystal agglomeration and crystal scars, and reduce the difficulty and frequency of maintenance;

[0022] 6. The inverted U-shaped mother liquor output pipe provided by the present invention can improve the crystal sedimentation effect as a whole, and keep the thickener liquid level stable, which helps to maintain a constant processing rate, thereby improving the overall production efficiency;

[0023] 7. The slurry discharge pipe provided by the present invention is arranged obliquely upward, and the angle with the vertical direction is 45° to 65°. Within this angle range, the friction resistance between the slurry and the inner wall of the pipe and the driving effect of gravity on the flow of the slurry can be better balanced. It can not only use gravity to help the slurry flow, but also will not produce excessive resistance, maintain the uniform flow of the slurry, reduce the breakage of the crystal, maintain stable discharge, effectively improve the quality of the slurry, and reduce the failure rate of the downstream centrifuge. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0025] Figure 1 A schematic diagram of the structure of the inorganic salt slurry thickening system provided by the present invention;

[0026] Figure 2 This is a cross-sectional view of the slurry distributor provided by the present invention.

[0027] The meanings of the symbols in the accompanying drawings are as follows:

[0028] 1—sedimentation section; 2—thickening section; 3—raw slurry feed pipeline; 4—raw slurry distributor; 41—side plate; 42—bottom plate; 43—small hole; 5—oil skimmer; 6—water phase return pipeline; 7—crystal slurry discharge pipe; 8—clarification mother liquor tank; 9—mother liquor output pipe; 10—agitation shaft; 11—agitation blade; 12—cleaning frame; 13—motor; 14—inspection port; 15—controller; 16—oil-water interface meter; 17—density meter. DETAILED DESCRIPTION

[0029] The present invention is further explained in detail below in conjunction with the drawings and descriptions of specific embodiments. However, the following descriptions including the embodiments are only used to enable ordinary technicians in the technical field to which the present invention belongs to more clearly understand the principles and essence of the present invention, and do not mean any form of limitation on the present invention.

[0030] like Figure 1As shown, the present invention provides an inorganic salt slurry thickening system for efficiently separating organic matter, comprising: a thickener, a raw slurry distributor 4, an oil skimmer 5 and a clarifying mother liquor tank 8, wherein the interior of the thickener is divided into an upper sedimentation section 1 and a lower thickening section 2, the sedimentation section 1 is open at the top, and the raw slurry distributor 4 is located in the sedimentation section 1, and is used for evenly distributing the raw slurry to be crystallized entering the sedimentation section 1.

[0031] The skimmer 5 is arranged at the top of the settling section 1, with the opening of the skimmer 5 facing upward (or the notch facing upward), and the notch of the skimmer 5 along the side wall of the thickener shell can be annular, semi-annular, or in any other suitable shape.

[0032] An organic component discharge port is provided on the thickener shell corresponding to the upper part of the skimmer tank 5, and a water phase outlet is provided on the thickener shell corresponding to the lower part of the skimmer tank 5. After the clear liquid in the sedimentation section 1 enters the skimmer tank 5, the organic matter (oil phase) and water will begin to separate due to the density difference. The organic matter will rise due to its low density and be discharged from the organic component discharge port at the upper part of the tank body, while the water will remain at the bottom due to its high density and be discharged from the water phase outlet at the lower part of the tank body.

[0033] Preferably, the system further comprises a water phase return pipeline 6, which is respectively connected to the water phase outlet and the settling section 1 to re-input the discharged water phase into the thickener to continue the crystallization process.

[0034] An inorganic salt slurry discharge port is provided at the bottom of the thick section 2, and the slurry reaching the target concentration is discharged from this discharge port.

[0035] The above-mentioned clarified mother liquor tank 8 is arranged at the upper part of the sedimentation section 1, and a mother liquor outlet is provided on the thickener shell corresponding to the lower part of the tank body of the clarified mother liquor tank 8. The mother liquor gradually rises in the sedimentation section 1, flows into the clarified mother liquor tank 8, and then is discharged from the thickener through the mother liquor outlet.

[0036] In some embodiments, the vertical position of the clarified mother liquor tank 8 is lower than the vertical position of the skimming tank 5, and the vertical distance between the top of the clarified mother liquor tank 8 and the bottom of the skimming tank 5 is 50 mm to 100 mm, and the clarified mother liquor tank 8 and the skimming tank 5 are both arranged in a ring or semi-ring shape on the side wall of the sedimentation section 1.

[0037] Furthermore, the system is also provided with a slurry discharge pipe 7 connected to the inorganic salt slurry discharge port. The slurry discharge pipe 7 is arranged obliquely upward, and the angle with the vertical direction is 45° to 65°. If the angle is too small, the resistance is large, which is not conducive to the discharge of the slurry. If the angle is too large, the slurry cannot achieve the effect of stable flow.

[0038] Furthermore, the sedimentation section 1 and the thickening section 2 both adopt a structure that is wide at the top and narrow at the bottom, including an upper cylindrical barrel section and a lower conical barrel section.

[0039] The diameter ratio of the cylindrical barrel section of the sedimentation section 1 to the cylindrical barrel section of the thickening section 2 is (2-3):1; the cone angles of the conical barrel section of the sedimentation section 1 and the conical barrel section of the thickening section 2 are the same, both of which are 60° to 120°.

[0040] Preferably, the tangent height of the sedimentation section 1 is 560m to 1500mm, and the tangent height of the thickening section 2 is 400m to 800mm.

[0041] In some embodiments, Figure 2 As shown, the raw pulp distributor 4 is connected to the raw pulp feed pipeline 3, and the raw pulp distributor 4 includes a side plate and a bottom plate 42. The side plate is connected to the bottom plate 42, and the side plate and the bottom plate 42 together enclose a cavity for accommodating the raw pulp. A number of vertically penetrating small holes 43 are evenly distributed on the bottom plate 42. The diameter of the small hole 43 is 20mm~30mm, and the opening rate of the bottom plate 42 is 60%~75%. The speed of the raw pulp passing through the small hole 43 is 0.4~1.0m / s. If the speed is too small, it is easy to get blocked. If the speed is too large, it is easy to cause disturbance, affecting the sedimentation efficiency.

[0042] In some embodiments, the thickener further comprises: a mother liquid outlet pipe 9 connected to the mother liquid outlet, the mother liquid outlet pipe 9 is in an inverted U shape as a whole, and along the vertical direction, the U-shaped top of the inverted U-shaped mother liquid outlet pipe 9 is higher than the position of the top of the skimmer 5, so that the liquid level in the thickener is balanced. Preferably, the distance between the U-shaped top and the top of the skimmer 5 is 10 mm-20 mm.

[0043] In some embodiments, the inorganic salt slurry thickening system also includes: an agitator, the agitator includes a stirring blade 11 and a stirring shaft 10, the stirring blade 11 is provided at one end of the stirring shaft 10 extending into the sedimentation section 1, and the stirring blade 11 is in the thickening section 2, the stirring shaft 10 drives the stirring blade 11 to generate radial flow, the diameter of the stirring blade 11 is 0.6 to 0.9 times the diameter of the thickening section 2, and the linear velocity of the outer edge of the stirring blade 11 is 0.3 m / s to 1.0 m / s. If the speed is too high, the crystals are easily broken, and if the speed is too low, the crystals are easily aggregated and blocked.

[0044] Furthermore, the agitator further comprises: a cleaning frame 12, which is provided at one end of the agitator shaft 10 extending into the thickening section 2, the cleaning frame 12 being close to the inner wall of the thickening section 2, the shape of the cleaning frame 12 being similar to the inner wall of the thickening section 2, and being 20 mm to 30 mm away from the inner wall of the thickening section 2. If the distance is too small, the agitator shaft 10 is prone to hitting the wall due to shaking, otherwise, the cleaning effect is poor. The cleaning frame 12 can effectively prevent crystal deposition and ensure that the materials in the entire thickener can effectively participate in the thickening process.

[0045] The preferred cleaning frame 12 is a metal flat steel having a thickness of 5 mm to 10 mm and a width of 8 mm to 15 mm.

[0046] In some embodiments, the thickener is further provided with an inspection port 14 for maintenance, and the inspection port 14 is preferably arranged at the bottom of the thickening section 2 .

[0047] In some embodiments, the inorganic salt slurry thickening system also includes: a controller 15 and an oil-water interface meter 16 and a density meter 17 respectively connected to the controller 15, wherein the oil-water interface meter 16 is arranged at the skimmer 5 for detecting the height value of the oil-water interface in the sedimentation section 1, and the density meter 17 is arranged at the inorganic salt slurry discharge port for detecting the slurry concentration in the thickening section 2.

[0048] The controller 15 is connected to the valve control at the organic component discharge port to control the opening and closing of the organic component discharge port according to the reading of the oil-water interface meter 16 to achieve accurate discharge of the organic component and the mother liquor.

[0049] The controller 15 is connected to the valve control at the inorganic salt slurry discharge port to control the switch of the inorganic salt slurry discharge port according to the reading of the density meter 17. When the slurry density reaches the target density (when a centrifuge is set downstream, the target density is the concentration required for centrifugal separation), the controller 15 controls the valve to open and discharge the slurry.

[0050] The operation process of the inorganic salt slurry thickening system is:

[0051] The raw slurry is input into the thickener through the raw slurry feed pipeline 3. The raw slurry distributor 4 controls the feed at a low speed to ensure that the raw slurry is distributed in a uniform and gentle manner to minimize the disturbance in the feeding process. The motor 13 drives the stirring shaft 10 to rotate, and then drives the stirring blade 11 to rotate, slowly and continuously stirring the thick slurry. The slurry is heated or cooled in the thickener, and the supersaturation of the inorganic salt in the slurry increases. The inorganic salt is continuously precipitated from the solution and attached to the crystal grains (nuclei), and the crystal grains gradually grow. As the crystal grows, the shape and size tend to be stable. The mature crystals will gradually settle to the lower thickening section 2 in the thickener due to the density difference and separate from the mother liquor. The density meter 17 detects the slurry concentration in the thickening section 2 in real time. When the slurry reaches the target density, the controller 15 controls the valve at the inorganic salt slurry outlet to open, and the slurry is discharged through the inclined slurry outlet pipe 7 for the next step of centrifugal dehydration and drying.

[0052] The mother liquor containing a very small amount of fine crystals flows into the clarified mother liquor tank 8 through overflow and is discharged through the mother liquor outlet pipe 9. Due to the density difference between the organic matter and the mother liquor, the organic matter floats on the liquid surface and enters the skimming tank 5. The oil-water interface meter 16 detects the height of the oil-water interface in real time. After the oil phase (organic matter) reaches the target height, the oil phase is discharged through the organic component discharge port to reduce the adhesion of organic matter on the crystal surface, thereby improving the purity of the final product. The water phase returns to the thickener through the water phase return pipeline 6 to continue crystallization. The discharge amount of the oil phase and the return amount of the water phase are controlled by the controller 15.

[0053] The ideal embodiment of the present invention is inspiration. Through the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical idea of ​​the present invention.

[0054] The technical scope of this invention is not limited to the contents in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An inorganic salt slurry thickening system for efficient separation of organic matter, It is characterized in that Including: thickener, raw pulp distributor, skimmer and clarified mother liquor tank; The interior of the thickener is divided into an upper settling section and a lower thickening section; The top of the settling section is open, and the slurry distributor is located in the settling section and is used to evenly distribute the slurry to be crystallized into the settling section; The skimmer is arranged at the top of the sedimentation section, an organic component discharge port is arranged on the thickener shell corresponding to the upper part of the skimmer body, and a water phase outlet is arranged on the thickener shell corresponding to the lower part of the skimmer body; The clarified mother liquor tank is arranged at the upper part of the sedimentation section, and a mother liquor outlet is arranged on the thickener shell corresponding to the lower part of the tank body of the clarified mother liquor tank; An inorganic salt slurry discharge port is provided at the bottom of the thick section.

2. The inorganic salt slurry thickening system according to claim 1, characterized in that: The sedimentation section and the thickening section both adopt a structure that is wide at the top and narrow at the bottom, including an upper cylindrical barrel section and a lower conical barrel section; The diameter ratio of the cylindrical barrel section of the settling section to the cylindrical barrel section of the thickening section is (2-3):1; The cone angle of the conical barrel section of the settling section is the same as that of the conical barrel section of the thickening section, both of which are 60° to 120°; The tangent height of the settling section is 560m~1500mm; The tangent height of the thick section is 400m to 800mm.

3. The inorganic salt slurry thickening system according to claim 1, characterized in that: The puree distributor comprises a side plate and a bottom plate, wherein the side plate is connected to the bottom plate, and the side plate and the bottom plate together enclose a cavity for containing the puree, and a plurality of vertically penetrating small holes are evenly distributed on the bottom plate; The diameter of the small hole is 20 mm to 30 mm; The opening rate of the bottom plate is 60% to 75%; The speed at which the raw pulp passes through the small holes is 0.4-1.0 m / s.

4. The inorganic salt slurry thickening system according to claim 1, characterized in that: The vertical position of the clarified mother liquor tank is lower than the vertical position of the skimming tank, and the vertical distance between the top of the clarified mother liquor tank and the bottom of the skimming tank is 50 mm to 100 mm.

5. The inorganic salt slurry thickening system according to claim 1, characterized in that: It also includes: a mother liquid output pipe connected to the mother liquid outlet, the mother liquid output pipe is in an inverted U shape as a whole; In the vertical direction, the U-shaped top of the inverted U-shaped mother liquor output pipe is higher than the top of the skimmer tank.

6. The inorganic salt slurry thickening system according to claim 1, characterized in that: Also includes: The agitator comprises a stirring blade and a stirring shaft. The stirring blade is arranged at one end of the stirring shaft extending into the sedimentation section, and the stirring blade is located in the thickening section.

7. The inorganic salt slurry thickening system according to claim 6, characterized in that: The agitator further comprises: a cleaning frame, The cleaning frame is provided at one end of the stirring shaft extending into the thick section. The cleaning frame is close to the inner side wall of the thick section and is 20 mm to 30 m away from the inner side wall of the thick section.

8. The inorganic salt slurry thickening system according to claim 1, characterized in that: It also includes: a slurry discharge pipe connected to the inorganic salt slurry discharge port, wherein the slurry discharge pipe is arranged obliquely upward and has an angle of 45° to 65° with the vertical direction.

9. The inorganic salt slurry thickening system according to claim 1, characterized in that: It also includes: a controller, and an oil-water interface meter and a density meter respectively connected to the controller for control; The oil-water interface meter is used to detect the height value of the oil-water interface in the settling section; The densitometer is used to detect the slurry concentration in the thick section; The controller is connected to the valve at the organic component discharge port to control the opening and closing of the organic component discharge port according to the reading of the oil-water interface meter; The controller is connected to the valve control at the inorganic salt slurry outlet to control the opening and closing of the inorganic salt slurry outlet according to the reading of the density meter.

10. The inorganic salt slurry thickening system according to claim 1, characterized in that: The thickener is also provided with an inspection port for maintenance.

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