Large-diameter compact fixed bed tail liquid filtering device and flow field regulation method

Abstract

The application provides a large-diameter compact fixed bed tail liquid filtering device and a flow field regulation method. The tail liquid filtering device separates the space at the bottom of an adsorption tower body into N filtering zones. The bottom of each filtering zone is provided with a liquid outlet for discharging tail liquid after separation of resin. The bottom of each liquid outlet is connected to a liquid outlet tail pipe. An adjusting valve is arranged on each liquid outlet tail pipe to regulate the liquid discharge flow of the liquid outlet tail pipe. The bottom outlets of the N liquid outlet tail pipes are connected to a liquid outlet main pipe. Each liquid outlet tail pipe is provided with a sampling port, and a sampling valve is arranged on the sampling port. The outlet of the liquid outlet main pipe is an adsorption tail liquid outlet. The resin bed lower part flow field is uniformly distributed, and the resin utilization rate is high.

Description

[0001] This invention application is a divisional application of the parent application "A large-diameter dense fixed-bed adsorption tower and its flow field control method", the application number of the parent application is 2022112851555, and the application date is October 20, 2022. Technical Field

[0002] This invention relates to the field of adsorption tower technology, and in particular to a large-diameter dense fixed bed tail liquid filtration device and flow field control method. Background Technology

[0003] The compacted fixed-bed adsorption tower is simple to operate and has a large throughput capacity. It is widely used for adsorption of leaching solutions in in-situ uranium mines. During the adsorption process, the resin inside the tower is in a compacted state. The adsorbent enters from the top of the tower and the tail liquid is discharged from the bottom of the tower.

[0004] In practical applications, dense fixed-bed adsorption towers are prone to problems such as bed channeling and large dead zones. For high-throughput, large-section dense fixed-bed adsorption towers, the tower diameter can reach more than 5.5 meters, which is significantly larger than the commonly used adsorption towers (3 meters in diameter). The height-to-diameter ratio of the resin bed becomes smaller accordingly, making the above problems more likely to occur. Moreover, as the diameter of the adsorption tower increases, the downward flow velocity of the adsorbent solution on the same horizontal cross section of the resin bed may vary greatly, that is, the flow field is uneven, resulting in inconsistent resin saturation and low resin utilization.

[0005] Currently, the compacted fixed-bed adsorption towers used in production have relatively small diameters (around 3 meters) and relatively high resin beds (around 4 meters), so the problem of uneven flow field distribution is not yet prominent. However, high-throughput compacted fixed-bed adsorption towers have a diameter of around 6 meters, and their horizontal cross-sectional area is four times that of commonly used adsorption towers, while the resin bed is still around 4 meters. Therefore, uneven flow field distribution becomes a problem that must be solved.

[0006] Currently, the compacted fixed-bed adsorption towers used in production have an adsorption liquid inlet at the top head. There is a space of about 2 meters above the resin bed (called the compaction layer), which is filled with adsorption liquid and serves to distribute the adsorption liquid evenly and compact the resin. At the bottom of the adsorption tower, there are filters arranged in a cross shape in the resin bed (their structure is usually a pipe with many small holes in the pipe wall as support, and the outside of the pipe is wrapped with multiple layers of wire mesh) to separate the resin and the adsorption tail liquid. The adsorption tail liquid flows out from the bottom of the tower through the pipe from the center of the cross shape.

[0007] The above structure is acceptable for adsorption towers with a diameter of less than 3 meters, but its direct application to adsorption towers with a diameter of 6 meters will cause the following problems:

[0008] 1. The adsorption solution is fed directly downwards from the top opening of the tower. Due to the large flow rate, the liquid directly impacts the resin directly below the feed inlet, forming a "pit". It also carries some resin into the compacted layer for circulation, causing instability in the upper resin bed.

[0009] 2. The cross-shaped filter at the bottom of the resin bed in the adsorption tower is the outlet of the adsorption tail liquid. Compared with the cross section with a diameter of 6 meters, the outlet area is too small and too concentrated, resulting in uneven flow field distribution in the lower part of the resin bed, excessive dead zone, small penetration volume of the adsorption tower, low resin saturation concentration, and low resin utilization rate.

[0010] 3. The filter mesh has low strength and is easily damaged; the filter layer is made of multiple layers of mesh, which is easily clogged by broken resin, and the filtration capacity decreases significantly with the accumulation of the processed volume. Summary of the Invention

[0011] The purpose of this invention is to address the technical deficiencies in the prior art by providing a large-diameter dense fixed bed tail liquid filtration device.

[0012] Another object of the present invention is to provide a method for flow field control of the tail liquid filtration device of the large-diameter dense fixed bed.

[0013] The technical solution adopted to achieve the purpose of this invention is:

[0014] A large-diameter compacted fixed bed tail liquid filtration device is disclosed. The tail liquid filtration device divides the bottom space of the adsorption tower into N filtration zones. The tail liquid filtration device is used to separate resin. Each filtration zone has a liquid outlet at the bottom to discharge the tail liquid after resin separation. The bottom of each liquid outlet is connected to a liquid outlet tail pipe. Each liquid outlet tail pipe is equipped with a regulating valve to control the liquid flow rate of the liquid outlet tail pipe. The bottom outlets of the N liquid outlet tail pipes are all connected to a main liquid outlet pipe. Each liquid outlet tail pipe is equipped with a sampling port and a sampling valve. The outlet of the main liquid outlet pipe is the adsorption tail liquid outlet.

[0015] The tail liquid filtration device includes N wire-wound screen tubes. Each wire-wound screen tube passes through the adsorption tower and is vertically inserted into the bottom of the resin bed to form a filtration zone. Each wire-wound screen tube is connected to one of the liquid outlets.

[0016] In the above technical solution, the bottom of the adsorption tower is divided into m annular partitions from the inside to the outside, and then each annular partition is evenly divided to finally form N filtration partitions.

[0017] In the above technical solution, the bottom of the adsorption tower body is divided into an inner ring and an outer ring of the same width from the inside to the outside. The outer ring has 8 filtration zones and the inner ring has 4 filtration zones. The bottom of the adsorption tower body is divided into 12 filtration zones.

[0018] In the above technical solution, the liquid outlet tailpipe at the lower part of the regulating valve is a transparent UPVC pipe, and each transparent UPVC pipe is provided with the sampling port.

[0019] In the above technical solution, manholes are provided on the top and bottom sidewalls of the adsorption tower, and the resin outlet is located at the bottom of the lower end cap of the adsorption tower.

[0020] In the above technical solution, the tail liquid filtration device includes N wire-wound screen tubes, each wire-wound screen tube is inserted vertically into the bottom of the resin bed through the adsorption tower to form a filtration zone, and each wire-wound screen tube is connected to one of the liquid outlets.

[0021] In the above technical solution, the wire-wound screen tube is composed of a support rib, V-shaped wires wound on the support rib, an end plate fixed to the top of the support rib, and a clamping plate fixed to the bottom of the support rib. The gap between the V-shaped wires is used for filtering resin.

[0022] In another aspect of the present invention, the flow field control method includes the following steps:

[0023] Sampling is performed at each outlet to measure the metal concentration of the tail liquid. This concentration is compared with the metal concentration of the tail liquid discharged from the main outlet. If the metal concentration of the tail liquid discharged from a certain outlet is 'a'% higher or lower than the metal concentration of the tail liquid discharged from the main outlet, the flow field in the resin bed zone corresponding to that outlet is considered abnormal. The regulating valve corresponding to that outlet is then adjusted. Specifically, if the metal concentration of the tail liquid discharged from a certain outlet is 'a'% higher than the metal concentration of the tail liquid discharged from the main outlet, the flow rate of that outlet is reduced by 10% through the regulating valve; if it is 'a'% lower, the flow rate of that outlet is increased by 10% through the regulating valve. After adjustment, the metal concentration is measured again to analyze whether normal adsorption has been achieved. If normal adsorption has not been achieved, the outlet flow rate is adjusted again based on the measured metal concentration until normal adsorption is achieved.

[0024] In the above technical solution, the value of 'a' ranges from 10 to 20.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The tail liquid filtration device of the present invention has a large filtration area, which is evenly distributed on the lower end cap of the adsorption tower, so as to achieve a uniform flow field in the resin bed and no dead flow corners.

[0027] 2. The present invention can improve the internal flow field of the resin bed by adjusting the liquid output of each outlet from the outside.

[0028] 3. The present invention utilizes supporting ribs and V-shaped wires to form a filter device, which is less prone to clogging and enhances the filtration capacity. Attached Figure Description

[0029] Figure 1 The diagram shows the structure of the adsorption tower of the present invention.

[0030] Figure 2 for Figure 1 Cross-sectional view of the middle AA section (the filter device uses the slotted sieve plate 13 described in Example 3).

[0031] Figure 3 This is a schematic diagram of the structure of the wire-wound screen tube in Example 2.

[0032] Figure 4 This is a schematic diagram of the arrangement structure of the wire-wound screen tube.

[0033] Figure 5 This is a schematic diagram of the structure of a wire-wound screen tube.

[0034] In the diagram: 1-Adsorption tower body, 2-Liquid distributor, 3-Liquid outlet, 4-Liquid outlet tail pipe, 5-Regulating valve, 6-Liquid outlet main pipe, 7-Sampling port, 8-Adsorption tail liquid outlet, 9-Liquid inlet, 10-Manhole, 11-Wire-wound screen tube, 12-Resin outlet, 13-Slotted screen plate, 14-Divider plate.

[0035] 4-1 Transparent UPVC pipe;

[0036] 11-1-Supporting rib, 11-2-V-shaped wire, 11-3-End plate, 11-4-Clamping plate. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] Example 1

[0039] A large-diameter dense fixed-bed adsorption tower includes an adsorption tower body 1. A liquid distributor 2 is provided at the top of the adsorption tower body 1 to introduce the adsorption stock solution. A resin bed is provided inside the adsorption tower body 1. The bottom space inside the adsorption tower body 1 is divided into N filtration zones by a slotted sieve plate 13 and partition plates 14. A gap exists between the slotted sieve plate 13 and the lower end cap of the adsorption tower. The partition plates 14 are installed within the gap to separate the N filtration zones. The slotted sieve plate 13 is used to separate the resin. Each filtration zone has a liquid outlet 3 at its bottom to discharge the tail liquid after resin separation. Each liquid outlet 3 is connected to a liquid outlet tail pipe 4 at its bottom. Each liquid outlet tail pipe 4 is equipped with a regulating valve 5 to control the liquid flow rate. The bottom outlets of all N liquid outlet tail pipes 4 are connected to a main liquid outlet pipe 6. Each liquid outlet tail pipe 4 is equipped with a sampling port 7 and a sampling valve. The outlet of the main liquid outlet pipe 6 is the adsorption tail liquid outlet 8.

[0040] Preferably, the liquid distributor 2 includes a connecting pipe and a blind plate. The connecting pipe extends into the adsorption tower body from the upper end cap. The upper part of the connecting pipe is connected to the liquid inlet 9. The lower part of the connecting pipe is welded to the blind plate. A certain number of through holes with a diameter of 30mm are opened on the connecting pipe and the blind plate.

[0041] Preferably, the bottom of the adsorption tower 1 is divided into m annular sections from the inside out, and then each annular section is further divided evenly to form N filtration sections. As shown in the figure, m=2, N=12, the bottom of the adsorption tower 1 is divided into inner and outer rings of equal width from the inside out, with the outer ring having 8 filtration sections and the inner ring having 4 filtration sections, resulting in 12 filtration sections in the bottom of the adsorption tower 1.

[0042] Preferably, the outlet tailpipe 4 at the lower part of the regulating valve 5 is a transparent UPVC pipe 4-1, which allows for observation of the fluid flow and resin leakage at each outlet 3 at any time. Each transparent UPVC pipe 4-1 is equipped with a sampling port 7, which allows for adjustment of the flow rate of each outlet 3 based on the comparison results of the tail liquid concentration at each outlet 3, thereby achieving control of the internal flow field of the resin bed.

[0043] Preferably, the adsorption tower body 1 is provided with manholes 10 on its top and bottom sidewalls, and the resin outlet 12 is located at the bottom of the lower end cap of the adsorption tower body 1.

[0044] Specifically, in this embodiment, the large-diameter dense fixed-bed adsorption tower has a tower diameter of 6m and a straight section height of 7m, with the resin bed height being 5m, as shown in the figure. The slotted sieve plate 13 is installed at a position approximately 100mm above the lower end cap, forming a 100mm high arc-shaped gap between the slotted sieve plate 13 and the lower end cap. This gap is divided into 12 zones by a stainless steel plate as a partition plate 14, with 8 zones in the outer ring and 4 zones in the inner ring. Each zone is connected to a DN150 adsorption tail liquid outlet pipe, and the 12 outlet pipes are combined to form the main outlet pipe 6. The slotted sieve plate 13 is composed of arc-shaped support ribs 11-1 and V-shaped wires 11-2 welded parallel to the support ribs 11-1. The gap between the V-shaped wires 11-2 is used for filtration. Preferably, the support ribs 11-1 are stainless steel support ribs 11-1, and the V-shaped wires 11-2 are V-shaped stainless steel wires. The V-shaped stainless steel wires have a cross-sectional width of 2mm, a height of 3mm, and a wire gap of 0.25mm.

[0045] In addition, the slotted sieve plate 13 can also be made into a conical or horizontal circular plate shape, which makes the manufacturing process simpler. The disadvantage is that it will sacrifice part of the volume of the lower end cap, so it cannot be used to hold resin.

[0046] Example 2

[0047] The tail liquid filtration device in this embodiment includes N wound wire screen tubes 11.

[0048] The tail liquid filtration device includes N wound wire screen tubes 11, each of which is vertically inserted into a corresponding filtration section. The insertion of the wound wire screen tubes 11 automatically forms the filtration section without the need for other components to separate them. Each wound wire screen tube 11 is connected to one of the liquid outlets 3, as shown in the figure. The wound wire screen tube 11 is composed of a support rib 11-1, V-shaped wires 11-2 wound on the support rib 11-1, an end plate 11-3 fixed to the top of the support rib 11-1, and a clamping plate 11-4 fixed to the bottom of the support rib 11-1. The gaps between the V-shaped wires 11-2 are used for filtration. Preferably, the support rib 11-1 and the V-shaped wires 11-2 are both made of stainless steel.

[0049] Specifically, in this embodiment, the large-diameter dense fixed-bed adsorption tower has a tower body diameter of 6m and a straight section height of 7m, with the resin bed height being 5m. As shown in the figure, the tail liquid filtration device includes 12 wound wire screen tubes 11, each with a height of 1100mm and an outer diameter of 280mm. The 12 wound wire screen tubes 11 are arranged in two rings on the lower end cap of the adsorption tower body. The outer ring has a distribution diameter of 4100mm and 8 liquid outlets are evenly distributed in 3 spans, while the inner ring has a distribution diameter of 1850mm and 4 liquid outlets are evenly distributed in 3 spans. The V-shaped wire 11-2 is a V-shaped stainless steel wire, and the supporting rib 11-1 is a stainless steel supporting rib. The V-shaped stainless steel wire has a cross-sectional width of 2mm, a height of 3mm, and a wire spacing of 0.25mm.

[0050] Example 3

[0051] The operation mode of the large-diameter dense fixed-bed adsorption tower in Examples 1-2 is as follows:

[0052] The adsorption solution is introduced into the adsorption tower 1 through the distributor 2. The distributor is positioned near the top of the resin bed, resulting in a low and uniform liquid flow rate that minimizes disturbance to the resin bed. After adsorption by the resin bed, the resin is filtered out by the tail liquid filtration device. The tail liquid from each filtration section enters the corresponding outlet tail pipe 4, then collects in the main outlet pipe 6, and is discharged from the adsorption tower 1 through the adsorption tail liquid outlet 8.

[0053] The uneven flow field within the resin bed will be reflected in the metal concentration of the adsorbed tail liquid. By analyzing the metal concentration of the tail liquid discharged from each outlet 3, the internal flow field of the resin bed region corresponding to each outlet 3 can be understood. By sampling through the sampling port 7, the metal concentration of the tail liquid discharged from each outlet 3 is detected and compared with the metal concentration of the tail liquid discharged from the main outlet pipe 6. The flow rate of each outlet 3 is then adjusted, thereby controlling the internal flow field of the resin bed.

[0054] For example, if the metal concentration of the tail liquid discharged from a certain outlet 3 is 15% higher or lower than the metal concentration of the tail liquid in the main outlet pipe 6, the flow field in the resin bed region corresponding to that outlet 3 is considered abnormal. In this case, the flow rate of that outlet 3 is changed by regulating valve 5 to improve the flow field in the corresponding resin bed region. Specifically, if the metal concentration of the tail liquid discharged from a certain outlet 3 is 15% higher than the metal concentration of the tail liquid in the main outlet pipe 6, the flow rate of that outlet 3 is reduced by 10% by regulating valve 5; if it is 15% lower, the flow rate of that outlet 3 is increased by 10% by regulating valve 5. After one hour of adjustment, the metal concentration is measured again to analyze whether normal adsorption has been achieved. If normal adsorption has not yet been achieved, the flow rate of outlet 3 is adjusted again based on the measured metal concentration until normal adsorption is achieved.

[0055] For example, a large-diameter dense fixed-bed adsorption tower with a processing capacity of 850m³ 3 The adsorption solution has a metal concentration of 30 mg / L. After adsorption begins, a sample is taken daily from the adsorption tail liquid outlet 8 to analyze the metal concentration. When the metal concentration reaches 0.4 mg / L, samples are taken every 6 hours from 12 sampling ports 7 and the adsorption tail liquid outlet 8 to analyze the metal concentration. If the metal concentration at a certain sampling port 7 is 15% higher or lower than the metal concentration at the adsorption tail liquid outlet 8, the flow rate of the outlet branch is adjusted by changing the opening of the corresponding regulating valve at that sampling port. If the metal concentration is too high, the flow rate is reduced by 10%; if the flow rate is too low, the flow rate is increased by 10%. After one hour of adjustment, another sample is taken to analyze whether the metal concentration deviation has decreased to within 15%. If the deviation is still greater than 15%, the flow rate of the tail liquid branch with the deviation is adjusted again based on the measured metal concentration results until the deviation decreases to within 15%.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for flow field control in a large-diameter, dense, fixed-bed tail liquid filtration device, characterized in that, The tail liquid filtration device divides the bottom space of the adsorption tower into N filtration zones. The tail liquid filtration device is used to separate resin. Each filtration zone has a liquid outlet at the bottom to discharge the tail liquid after resin separation. The bottom of each liquid outlet is connected to a liquid outlet tail pipe. Each liquid outlet tail pipe is equipped with a regulating valve to control the liquid flow rate of the liquid outlet tail pipe. The bottom outlets of the N liquid outlet tail pipes are all connected to the liquid outlet main pipe. Each liquid outlet tail pipe is equipped with a sampling port and a sampling valve. The outlet of the liquid outlet main pipe is the adsorption tail liquid outlet. The bottom of the adsorption tower is divided into m annular partitions from the inside to the outside, and then each annular partition is evenly divided to form N filtration partitions. The tail liquid filtration device includes N wire-wound screen tubes. Each wire-wound screen tube passes through the adsorption tower and is vertically inserted into the bottom of the resin bed to form a filtration zone. Each wire-wound screen tube is connected to one of the liquid outlets. The wire-wound screen tube consists of supporting ribs, V-shaped wires wound on the supporting ribs, an end plate fixed to the top of the supporting ribs, and a clamping plate fixed to the bottom of the supporting ribs. The gaps between the V-shaped wires are used for filtering resin. The flow field control method includes the following steps: Sampling is performed at each outlet to measure the metal concentration of the tail liquid. This concentration is then compared with the metal concentration of the tail liquid discharged from the main outlet. If the metal concentration of the tail liquid discharged from a certain outlet is 'a'% higher or lower than the metal concentration of the tail liquid discharged from the main outlet, the flow field in the resin bed zone corresponding to that outlet is considered abnormal. The regulating valve corresponding to that outlet is then adjusted. Specifically, if the metal concentration of the tail liquid discharged from a certain outlet is 'a'% higher than the metal concentration of the tail liquid discharged from the main outlet, the flow rate of that outlet is reduced by 10% through the regulating valve. If it is 'a'% lower, the flow rate of that outlet is increased by 10% through the regulating valve. After adjustment, the metal concentration is measured again to analyze whether the normal adsorption state has been reached. If the normal adsorption state has not been reached, the flow rate of the outlet is adjusted again based on the measured metal concentration until the normal adsorption state is reached.

2. The flow field control method for the tail liquid filtration device of a large-diameter dense fixed bed as described in claim 1, characterized in that, The bottom of the adsorption tower is divided into an inner ring and an outer ring of equal width from the inside to the outside. The outer ring has 8 filtration zones and the inner ring has 4 filtration zones. The bottom of the adsorption tower is divided into 12 filtration zones.

3. The flow field control method for the large-diameter dense fixed bed tail liquid filtration device as described in claim 1, characterized in that, The liquid outlet tailpipe at the bottom of the regulating valve is a transparent UPVC pipe, and each transparent UPVC pipe is provided with the sampling port.

4. The flow field control method for the tail liquid filtration device of a large-diameter dense fixed bed as described in claim 1, characterized in that, Manholes are provided on the top and bottom sidewalls of the adsorption tower, and the resin outlet is located at the bottom of the lower end cap of the adsorption tower.

5. The flow field control method for the tail liquid filtration device of a large-diameter dense fixed bed as described in claim 1, characterized in that, The value of a ranges from 10 to 20.

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