Fluorosilicic acid concentration device

Abstract

The present invention proposes a device for concentrating fluorosilicic acid, which relates to the technical field of chemical equipment. The concentrating device includes a concentrating tower, a gas heater, and a heat exchanger. The concentrating tower is provided with a liquid inlet, a liquid outlet, a first reflux port, and an air outlet. The liquid inlet is suitable for connecting to a liquid storage source that can provide fluorosilicic acid. The air inlet end of the gas heater is connected to the air outlet. The heat exchanger has a first heat exchange channel and a second heat exchange channel for mutual heat exchange. One end of the first heat exchange channel is connected to the air outlet end of the gas heater, and the other end is connected to the air inlet end of the gas heater. One end of the second heat exchange channel is connected to the liquid outlet, and the other end is connected to the first reflux port. The device for concentrating fluorosilicic acid in the present invention can recycle the heat of the steam generated during the fluorosilicic acid concentration process, thereby improving the energy utilization rate of the concentrating device.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical equipment, in particular to a fluosilicic acid concentration device. Background Art

[0002] In the related art, anhydrous hydrogen fluoride can be prepared from fluorosilicic acid by using sulfuric acid decomposition method. Fluosilicic acid mainly comes from by-products of the phosphate fertilizer industry and the anhydrous hydrogen fluoride industry, and its concentration is relatively low. Therefore, before preparing anhydrous hydrogen fluoride, the fluorosilicic acid needs to be concentrated to meet the preparation requirements; wherein, the water in the fluorosilicic acid can be evaporated by heating the fluorosilicic acid to form low-temperature water vapor, so as to achieve the purpose of concentrating the fluorosilicic acid, but the formed low-temperature water vapor is not utilized and is directly discharged from the concentration device, resulting in energy waste. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] Therefore, one object of the present invention is to provide a fluosilicic acid concentration device that can recover and utilize the heat of steam generated during the fluosilicic acid concentration process, thereby improving the energy utilization rate of the concentration device.

[0005] According to an embodiment of the present invention, a concentrating device for fluorosilicic acid includes a concentrating tower, a gas heater and a heat exchanger. The concentrating tower is provided with a liquid inlet, a liquid outlet, a first reflux port and an air outlet. The liquid inlet is suitable for connecting to a liquid storage source that can provide fluorosilicic acid. The air inlet end of the gas heater is connected to the air outlet. The heat exchanger has a first heat exchange channel and a second heat exchange channel for mutual heat exchange. One end of the first heat exchange channel is connected to the air outlet end of the gas heater, and the other end is connected to the air inlet end of the gas heater. One end of the second heat exchange channel is connected to the liquid outlet, and the other end is connected to the first reflux port.

[0006] According to the fluosilicic acid concentration device of the embodiment of the present invention, the heat of the steam generated during the fluosilicic acid concentration process can be recovered and utilized, thereby improving the energy utilization rate of the concentration device.

[0007] In addition, the fluosilicic acid concentration device according to the above embodiment of the present invention may also have the following additional technical features:

[0008] Optionally, the gas heater is configured as a compressor.

[0009] Optionally, the compressor is a diaphragm compressor.

[0010] Optionally, the concentrating device further includes a gas-liquid-solid separator, which is connected between the gas outlet and the gas inlet end of the gas heater.

[0011] Optionally, the concentration tower is further provided with a second reflux port, the gas-liquid-solid separator is provided with an inlet, a first outlet and a second outlet, the inlet is connected to the gas outlet, the first outlet is connected to the gas inlet end of the gas heater, and the second outlet is connected to the second reflux port.

[0012] Optionally, the gas-liquid-solid separator is also provided with a flushing port, and the concentrating device further includes a first pump assembly, the inlet end of the first pump assembly is suitable for connecting to the liquid storage source, the outlet end of the first pump assembly is connected to the flushing port, and the first pump assembly is used to drive the fluorosilicic acid in the liquid storage source to flow to the gas-liquid-solid separator to flush the solid-liquid impurities separated by the gas-liquid-solid separator.

[0013] Optionally, the outlet end of the first pump assembly is also connected to the liquid inlet, and the first pump assembly is used to drive the fluorosilicic acid in the liquid storage source to flow toward the concentration tower.

[0014] Optionally, the gas-liquid-solid separator includes a shell, a packing layer, a filter screen and a first demister, the packing layer, the filter screen and the first demister are all arranged in the shell, the shell is provided with an inlet and a first outlet, the inlet is connected to the air outlet, the first outlet is connected to the air inlet end of the gas heater, the inlet and the first outlet are respectively provided with the filter screen, the first demister and the filter screen are spaced apart, and the packing layer is provided between the first demister and the filter screen.

[0015] Optionally, the concentrating device further includes a gas-liquid separator, which is connected between the first heat exchange channel and the gas inlet end of the gas heater.

[0016] Optionally, the concentrating device further includes a first pump assembly and a second pump assembly, wherein the first pump assembly is adapted to be connected between the liquid storage source and the liquid inlet, and the second pump assembly is connected between the liquid outlet and the second heat exchange channel.

[0017] Optionally, the liquid inlet and the liquid outlet are arranged at the lower part of the concentrating tower, the first reflux port is arranged at the middle part of the concentrating tower, and the gas outlet is arranged at the upper part of the concentrating tower.

[0018] Optionally, a second demister is provided at the air outlet.

[0019] Optionally, there are multiple heat exchangers, and the first heat exchange channels of the multiple heat exchangers are connected in parallel between the gas outlet end and the gas inlet end of the gas heater, and the second heat exchange channels of the multiple heat exchangers are connected in parallel between the liquid outlet and the first reflux port, and any one of the multiple heat exchangers can be selectively set to be connected or isolated.

[0020] Optionally, the concentration device also includes a spray assembly and a first pump assembly, the inlet end of the first pump assembly is suitable for connecting to the liquid storage source, the outlet end of the first pump assembly is connected to the spray assembly, and the first pump assembly is used to drive the fluorosilicic acid in the liquid storage source to flow to the spray assembly, the spray assembly is arranged in the concentration tower, and is used to spray the gas flowing toward the gas outlet.

[0021] Optionally, the concentration tower includes a first tower section and a second tower section, the first tower section is arranged on the upper side of the second tower section, and the cross-sectional area of the first tower section is smaller than the cross-sectional area of the second tower section, the gas outlet is formed at the top of the first tower section, the spray assembly is arranged in the first tower section and is located below the gas outlet, the spray assembly includes a plurality of spray units spaced apart from top to bottom, and each of the spray units includes at least one spiral nozzle.

[0022] Optionally, the air flow inlet is located in the fan cavity, and the air flow outlet is located in the compressor cavity.

[0023] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 Schematic diagram of a device for concentrating fluorosilicic acid in some embodiments of the present invention.

[0026] Reference numerals:

[0027] Concentration device 100, liquid storage source 10, concentration tower 20, liquid inlet 21, liquid outlet 22, first reflux port 23, gas outlet 24, second reflux port 25, first tower section 26, second tower section 27, gas heater 30, heat exchanger 40, first heat exchange channel 41, second heat exchange channel 42, gas-liquid-solid separator 50, inlet 51, first outlet 52, second outlet 53, flushing port 54, gas-liquid separator 60, second demister 70, spray assembly 80, first pump assembly 91, second pump assembly 92. DETAILED DESCRIPTION

[0028] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0029] In the related art, anhydrous hydrogen fluoride can be prepared from fluorosilicic acid by using sulfuric acid decomposition method. Fluosilicic acid mainly comes from by-products of the phosphate fertilizer industry and the anhydrous hydrogen fluoride industry, and its concentration is relatively low. Therefore, before preparing anhydrous hydrogen fluoride, the fluorosilicic acid needs to be concentrated to meet the preparation requirements; wherein, the water in the fluorosilicic acid can be evaporated by heating the fluorosilicic acid to form low-temperature water vapor, so as to achieve the purpose of concentrating the fluorosilicic acid, but the formed low-temperature water vapor is not utilized and is directly discharged from the concentration device, resulting in energy waste.

[0030] Therefore, the present invention provides a fluosilicic acid concentration device 100 , which can recover and utilize the heat of steam generated during the fluosilicic acid concentration process, thereby improving the energy utilization rate of the concentration device 100 .

[0031] like Figure 1 According to an embodiment of the present invention, the concentrating device 100 for fluorosilicic acid includes a concentrating tower 20 , a gas heater 30 , and a heat exchanger 40 .

[0032] Among them, the concentration tower 20 is provided with a liquid inlet 21, a liquid outlet 22, a first reflux port 23 and an air outlet 24. The liquid inlet 21 is suitable for connecting to a liquid storage source 10 (such as a liquid storage tank) that can provide fluorosilicic acid. For example, the liquid storage source 10 is used to store fluorosilicic acid and can provide fluorosilicic acid to the concentration device 100. The fluorosilicic acid in the liquid storage source 10 can flow into the concentration tower 20 through the liquid inlet 21; the air inlet end of the gas heater 30 is connected to the air outlet 24, and the heat exchanger 40 has a first heat exchange channel 41 and a second heat exchange channel 42 for mutual heat exchange, one end of the first heat exchange channel 41 is connected to the air outlet end of the gas heater 30, and the other end is connected to the air inlet end of the gas heater 30, one end of the second heat exchange channel 42 is connected to the liquid outlet 22, and the other end is connected to the first reflux port 23; with this arrangement, the heat of the steam generated during the fluorosilicic acid concentration process can be recovered and utilized, thereby improving the energy utilization rate of the concentration device 100.

[0033] The working principle of the concentrator 100 is as follows:

[0034] When the concentration tower 20 is initially fed, the fluorosilicic acid in the liquid storage source 10 enters the concentration tower 20 through the liquid inlet 21. During this process, the fluorosilicic acid can be heated by an external heat source so that the moisture in the fluorosilicic acid forms low-temperature steam, wherein the low-temperature steam is converted into high-temperature steam after being heated by the gas heater 30. The high-temperature steam is converted into low-temperature steam after heating the fluorosilicic acid in the heat exchanger 40 and flows back to the air inlet end of the gas heater 30 to reuse the heat of the low-temperature steam, thereby reducing the energy required to heat the fluorosilicic acid and improving energy utilization. There is no need to heat the fluorosilicic acid through an external heat source subsequently. Through the cooperation of the gas heater 30 and the heat exchanger 40, the continuous operation of the concentration device 100 can be achieved; specifically, the low-temperature steam can flow through the air outlet 24 of the concentration tower 20, the air inlet end of the gas heater 30, the air outlet end of the gas heater 30, the first heat exchange channel 41 of the heat exchanger 40 in sequence, and finally flow back to the air inlet end of the gas heater 30.

[0035] In addition, with the continuous feeding of the concentration tower 20, the fluorosilicic acid can circulate between the concentration tower 20 and the heat exchanger 40, so that the fluorosilicic acid can be heated to evaporate the water therein, thereby concentrating the fluorosilicic acid and providing a new steam heat source for the heat exchanger 40. When the concentration of the fluorosilicic acid reaches a predetermined value, the fluorosilicic acid is discharged from the concentration device 100. For example, the liquid storage source 10 stores 18%-23% fluorosilicic acid. After being concentrated in the concentration tower 20, the fluorosilicic acid is concentrated to 36%-40%. At this time, the fluorosilicic acid meets the predetermined value and can be discharged from the concentration device 100 to enter the subsequent preparation process.

[0036] It should be understood that during the heating and concentration process, fluorosilicic acid will also be heated to produce hydrogen fluoride and silicon tetrafluoride, and silicon tetrafluoride will react with water to produce hydrofluoric acid and silicon dioxide. Therefore, in some examples, the high-temperature steam can be controlled within the range of 40°C-50°C by the gas heater 30, and the fluorosilicic acid can be driven to flow rapidly through the second heat exchange channel 42 by the first pump assembly 91. In this way, the fluorosilicic acid can be heated to evaporate low-temperature steam while reducing the generation of impurities such as hydrofluoric acid and silicon dioxide.

[0037] In addition, there are multiple heating methods for the gas heater 30. For example, the gas heater 30 can be set as an electric heater to convert low-temperature steam into high-temperature steam through electrical energy; for example, the gas heater 30 can be set as a gas heater to convert low-temperature steam into high-temperature steam through chemical energy; of course, the above examples cannot be understood as limiting the scope of protection of the present invention.

[0038] like Figure 1In some embodiments of the present invention, the gas heater 30 can also be configured as a compressor having an air inlet and an air outlet. The air inlet of the compressor is connected to the air outlet 24 of the concentration tower 20, and the air outlet of the compressor is connected to the first heat exchange channel 41 of the heat exchanger 40. The compressor converts the low-temperature steam discharged from the concentration tower 20 into high-temperature steam by pressurizing the low-temperature steam, and discharges the high-temperature steam to the heat exchanger 40, so as to provide a heat source for the heat exchanger 40, so as to heat the fluorosilicic acid and evaporate the water, thereby achieving the purpose of concentrating the fluorosilicic acid.

[0039] Furthermore, the compressor can be a diaphragm compressor; it is understandable that the low-temperature steam in the concentration tower 20 will entrain some liquid impurities in the process of being discharged to the compressor, affecting the operation of the compressor. Therefore, the compressor can be set as a diaphragm compressor. The diaphragm compressor can allow some liquid to enter during operation without affecting its working performance, so that the concentration device 100 can operate stably.

[0040] like Figure 1 In some embodiments of the present invention, the concentration device 100 further includes a gas-liquid-solid separator 50, which is connected between the gas outlet 24 and the gas inlet end of the gas heater 30; in this way, impurities in the low-temperature steam can be separated by the gas-liquid-solid separator 50 to prevent the impurities from affecting the recovery and utilization of the steam.

[0041] Specifically, in combination with the aforementioned example, the fluorosilicic acid in the concentration device 100 is prone to produce liquid impurities of hydrofluoric acid and solid impurities of silicon dioxide during the heating process. These impurities affect the recovery and utilization of steam, so before the concentration tower 20 discharges the low-temperature steam to the gas heater 30, the low-temperature steam needs to be filtered and separated; therefore, a gas-liquid-solid separator 50 may be provided between the gas outlet 24 of the concentration tower 20 and the gas inlet end of the gas heater 30, and the solid-liquid impurities in the low-temperature steam are separated by the gas-liquid-solid separator 50 to prevent the impurities from affecting the recovery and utilization of the steam.

[0042] like Figure 1 In some embodiments of the present invention, the concentration tower 20 is further provided with a second reflux port 25, and the gas-liquid-solid separator 50 is provided with an inlet 51, a first outlet 52 and a second outlet 53, the inlet 51 is connected to the gas outlet 24, the first outlet 52 is connected to the gas inlet end of the gas heater 30, and the second outlet 53 is connected to the second reflux port 25; such a configuration allows the impurities to flow back into the concentration tower 20, facilitating subsequent centralized treatment of the impurities and reducing costs.

[0043] It can be understood that when the fluorosilicic acid is heated, it decomposes into some impurities such as hydrofluoric acid and silica in the concentration tower 20. Some of the impurities can be entrained in the low-temperature steam and discharged. The low-temperature steam can be discharged from the exhaust port of the concentration tower 20, enter from the inlet 51 of the gas-liquid-solid separator 50, and be discharged to the gas heater 30 from the first outlet 52 of the gas-liquid-solid separator 50. The silica and hydrofluoric acid entrained in the low-temperature steam can be separated by the gas-liquid-solid separator 50 and reflux into the concentration tower 20 along the second outlet 53 of the gas-liquid-solid separator 50 and the second reflux port 25 of the concentration tower 20, and gather together with the small amount of silica and a small amount of hydrofluoric acid in the concentration tower 20. After the concentration of the fluorosilicic acid is completed, the impurities in the concentrated fluorosilicic acid can be centrally processed without the need to set up additional storage containers to store the impurities separated by the gas-liquid-solid separator 50, thereby greatly reducing the cost of the concentration device 100.

[0044] like Figure 1 In some embodiments of the present invention, the gas-liquid-solid separator 50 is further provided with a flushing port 54, which is connected to the second outlet 53, and the flushing port 54 can be suitable for the introduction of a flushing medium; it can be understood that as the gas-liquid-solid separator 50 is used for a long time, some solid-liquid impurities accumulate inside the gas-liquid-solid separator 50 and cannot flow back into the concentration tower 20. Therefore, a flushing medium can be introduced into the flushing port 54 to flush the solid-liquid impurities in the gas-liquid-solid separator 50 back to the concentration tower 20. The flushing medium can be fluorosilicic acid; in this way, the working performance of the gas-liquid-solid separator 50 can be ensured, and impurities can be prevented from affecting the recovery and utilization of steam.

[0045] Furthermore, the fluorosilicic acid in the liquid storage source 10 can be used, and there is no need to introduce additional fluorosilicic acid, which reduces costs, reduces external intervention, and improves the operating stability of the concentration device 100; specifically, the concentration device 100 also includes a first pump component 91, and the first pump component 91 is suitable for connecting between the liquid storage source 10 and the flushing port 54. The inlet end of the first pump component 91 is suitable for connecting to the liquid storage source 10, and the outlet end of the first pump component 91 is connected to the flushing port 54. The first pump component 91 can be used to drive the fluorosilicic acid in the liquid storage source 10 to flow to the gas-liquid-solid separator 50. The fluorosilicic acid enters from the flushing port 54 of the gas-liquid-solid separator 50 to flush the solid-liquid impurities separated by the gas-liquid-solid separator 50, so that the solid-liquid impurities can flow back to the concentration tower 20 along the second outlet 53 and the second reflux port 25; in this way, the working performance of the gas-liquid-solid separator 50 can be ensured, and impurities can be prevented from affecting the recovery and utilization of steam.

[0046] like Figure 1In some embodiments of the present invention, the outlet end of the first pump assembly 91 is also connected to the liquid inlet 21, so that the first pump assembly 91 is also suitable for connection between the liquid storage source 10 and the liquid inlet 21. The first pump assembly 91 is used to drive the fluorosilicic acid in the liquid storage source 10 to flow to the concentrating tower 20. This can improve the feeding stability of the concentrating tower 20, avoid the problem of the fluorosilicic acid in the liquid storage source 10 being unable to flow to the concentrating tower 20 due to installation position problems, and facilitate the flexible setting of the relative position between the concentrating tower 20 and the liquid storage source 10. As a result, the first pump assembly 91 can drive the fluorosilicic acid in the liquid storage source 10 to flow to the gas-liquid-solid separator 50, and can also drive the fluorosilicic acid in the liquid storage source 10 to flow to the concentrating tower 20. This is a multi-purpose device that helps simplify the structure of the concentrating device 100.

[0047] like Figure 1 In some embodiments of the present invention, the gas-liquid-solid separator 50 includes a shell, a packing layer, a filter screen and a first demister. The packing layer, the filter screen and the first demister are all arranged in the shell. The shell is provided with an inlet 51 and a first outlet 52. The inlet 51 is connected to the air outlet 24, and the first outlet 52 is connected to the air inlet end of the gas heater 30. The inlet 51 and the first outlet 52 are respectively provided with a filter screen. The first demister and the filter screen are arranged at intervals, and a packing layer is provided between the first demister and the filter screen. In this way, the separation efficiency can be improved and impurities can be prevented from affecting the recovery and utilization of steam.

[0048] Specifically, the inlet 51 of the shell is provided with a first filter, the first outlet 52 of the shell is provided with a second filter, a first demister is arranged between the first filter and the second filter, and a packing layer is provided between the first demister and the first filter and the second filter, respectively. In this way, when the low-temperature steam passes through the gas-liquid-solid separator 50, it can first pass through the first filter, the packing layer to the demister, thereby realizing the coarse separation to the fine separation of the low-temperature steam and improving the separation system efficiency; then the low-temperature steam can pass through the packing layer and the second filter, and the low-temperature steam can be separated again to further improve the separation efficiency.

[0049] In addition, in combination with the above, the packing layer, filter screen and first demister can be regularly flushed with the help of fluorosilicic acid in the liquid storage source 10 to avoid excessive impurities on the packing layer, filter screen and first demister, which may affect the separation efficiency of the gas-liquid-solid separator 50.

[0050] like Figure 1In some embodiments of the present invention, the concentration device 100 further includes a gas-liquid separator 60, which is connected between the first heat exchange channel 41 and the air inlet end of the gas heater 30; it can be understood that when the high-temperature steam flows through the first heat exchange channel 41, it exchanges heat with the fluorosilicic acid flowing through the second heat exchange channel 42, that is, the high-temperature steam transfers heat to the fluorosilicic acid, so that the high-temperature steam is converted into low-temperature steam again. In particular, the high-temperature steam is directly liquefied into water. At this time, in order to avoid the influence of moisture on the recycling of steam, a gas-liquid separator 60 can be provided between the first heat exchange channel 41 and the air inlet end of the gas heater 30, and the water in the low-temperature steam is separated by the gas-liquid separator 60 to improve the working stability of the concentration device 100.

[0051] like Figure 1 In some embodiments of the present invention, the concentration device 100 also includes a first pump component 91 and a second pump component 92. The first pump component 91 is suitable for connecting between the liquid storage source 10 and the liquid inlet 21. The first pump component 91 can drive the fluorosilicic acid in the liquid storage source 10 into the concentration tower 20 through the liquid inlet 21 of the concentration tower 20 to concentrate the fluorosilicic acid. The inlet end of the first pump component 91 is suitable for connecting to the liquid storage source 10, and the outlet end of the first pump component 91 is suitable for connecting to the liquid inlet 21; the second pump component 92 is connected between the liquid outlet 22 and the second heat exchange channel 42, and can drive the fluorosilicic acid to circulate between the concentration tower 20 and the heat exchanger 40 to heat the fluorosilicic acid, so that the water in the fluorosilicic acid is converted into low-temperature steam, thereby achieving the concentration of the fluorosilicic acid.

[0052] like Figure 1 In some embodiments of the present invention, the liquid inlet 21 is arranged at the lower part of the concentration tower 20. In this way, when fluorosilicic acid is fed, the impact of the feed on the structure of the concentration tower 20 can be reduced, and the damage to the concentration tower 20 can be reduced; the liquid outlet 22 is arranged at the lower part of the concentration tower 20. In this way, the fluorosilicic acid can be easily discharged from the concentration tower 20; the first reflux port 23 is arranged in the middle part of the concentration tower 20, which can facilitate the reflux of fluorosilicic acid to the concentration tower 20, and avoid the liquid level of fluorosilicic acid in the concentration tower 20 being higher than the first reflux port 23, which makes it impossible for the fluorosilicic acid to reflux; the gas outlet 24 is arranged at the upper part of the concentration tower 20. In this way, the low-temperature steam generated by the heating of fluorosilicic acid can be discharged, and the discharge of liquid impurities and solid impurities entrained by the low-temperature steam can be minimized.

[0053] like Figure 1 In some embodiments of the present invention, a second demister 70 is provided at the gas outlet 24. The second demister 70 can remove liquid droplets and impurities entrained by the low-temperature steam, thereby preventing the impurities from affecting the recycling of the low-temperature steam. In some examples, the second demister 70 can be a wire mesh demister.

[0054] like Figure 1In some embodiments of the present invention, there are multiple heat exchangers 40, and the first heat exchange channels 41 of the multiple heat exchangers 40 are connected in parallel between the gas outlet end of the gas heater 30 and the gas inlet end of the gas heater 30, and the second heat exchange channels 42 of the multiple heat exchangers 40 are connected in parallel between the liquid outlet 22 and the first reflux port 23. Any one of the multiple heat exchangers 40 can be selectively connected or disconnected; in this way, the operating stability of the concentration device 100 can be guaranteed, the continuous operation of the concentration device 100 can be ensured, and the working efficiency can be improved.

[0055] Exemplarily, the concentrating device 100 includes a first heat exchanger and a second heat exchanger, the first heat exchange channel 41 of the first heat exchanger and the first heat exchange channel 41 of the second heat exchanger are connected in parallel between the gas heater 30 and the gas outlet and the gas inlet of the gas heater 30, the second heat exchange channel 42 of the first heat exchanger and the second heat exchange channel 42 of the second heat exchanger are connected in parallel between the liquid outlet 22 and the first reflux port 23; during normal operation, high-temperature steam can flow through the first heat exchange channel 41 of the first heat exchanger, and fluorosilicic acid can flow through the second heat exchange channel 42 of the first heat exchanger. When the first heat exchanger is damaged, the first heat exchanger can be isolated and the second heat exchanger can be connected. At this time, high-temperature steam can flow through the first heat exchange channel 41 of the second heat exchanger, and fluorosilicic acid can flow through the second heat exchange channel 42 of the second heat exchanger; in this way, the first heat exchanger and the second heat exchanger can be used in parallel and used in parallel to ensure the stable operation of the concentrating device 100.

[0056] like Figure 1 In some embodiments of the present invention, the concentration device 100 further includes a spray assembly 80 and a first pump assembly 91. The inlet end of the first pump assembly 91 is suitable for connecting to the liquid storage source 10, and the outlet end of the first pump assembly 91 is connected to the spray assembly 80. The first pump assembly 91 is used to drive the fluorosilicic acid in the liquid storage source 10 to flow to the spray assembly 80. The spray assembly 80 is arranged in the concentration tower 20 and is used to spray the gas flowing to the gas outlet 24. In this way, impurities in the low-temperature steam can be removed to avoid affecting the recycling of the low-temperature steam.

[0057] As can be seen from the above, in addition to producing low-temperature steam, heating of fluorosilicic acid may also produce a small amount of hydrofluoric acid and silicon dioxide. Therefore, a spray component 80 can be provided in the concentration tower 20. The spray component 80 is connected to the liquid storage source 10 through the first pump component 91. The first pump component 91 pumps the fluorosilicic acid in the liquid storage source 10 to the spray component 80, and the spray component 80 sprays the low-temperature steam flowing to the air outlet 24, thereby removing impurities such as hydrofluoric acid and silicon dioxide entrained in the low-temperature steam, so as to avoid affecting the recycling of the low-temperature steam.

[0058] In combination with the foregoing, in some specific examples, the concentrating device 100 also includes a first valve assembly, the inlet end of the first pump assembly 91 is suitable for connecting to the liquid storage source 10, and the first valve assembly is respectively connected to the first pump assembly 91, the liquid inlet 21 of the concentrating tower 20, the flushing port 54 of the gas-liquid-solid separator 50 and the spray assembly 80; when the concentrating device 100 is working, the first pump assembly 91 pumps out the fluorosilicic acid in the liquid storage source 10, and the first valve assembly controls the flow direction of the fluorosilicic acid to realize the feeding of the concentrating tower 20, the flushing of the gas-liquid-solid separator 50 and the spraying of the spray assembly 80; illustratively, the first valve assembly is connected to the outlet end of the first pump assembly 91 and is a reversing valve to control the flow direction of the fluorosilicic acid.

[0059] In other specific examples, the concentrating device 100 also includes a second valve assembly and a drainage channel, the second pump assembly 92 is connected to the liquid outlet 22, and the second valve assembly is respectively connected to the second pump assembly 92, one end of the second heat exchange channel 42 and the drainage channel; when the concentrating device 100 is working, the second pump assembly 92 pumps out the fluorosilicic acid in the concentrating tower 20, and the second valve assembly controls the flow direction of the fluorosilicic acid to realize the circulation of fluorosilicic acid between the concentrating tower 20 and the heat exchanger 40, and to discharge the fluorosilicic acid from the concentrating device 100; illustratively, the second valve assembly is connected to the outlet end of the second pump assembly 92 and is a reversing valve to control the flow direction of the fluorosilicic acid.

[0060] like Figure 1 In some embodiments of the present invention, the concentration tower 20 includes a first tower section 26 and a second tower section 27. The first tower section 26 is arranged on the upper side of the second tower section 27, and the cross-sectional area of the first tower section 26 is smaller than the cross-sectional area of the second tower section 27. The gas outlet 24 is formed at the top of the first tower section 26, and the spray assembly 80 is arranged in the first tower section 26 and below the gas outlet 24. It can be understood that the second tower section 27 can be used to provide an accommodation space for the concentration of fluosilicic acid, and the first tower section 26 can be used to reduce the flow area of the low-temperature steam, so as to facilitate the spray assembly 80 to spray the low-temperature steam and improve the removal effect of impurities.

[0061] In addition, the spray assembly 80 includes a plurality of spray units spaced apart from top to bottom, and each spray unit includes at least one spiral nozzle; in this way, through the plurality of spray units arranged up and down, multi-stage spraying of low-temperature steam can be achieved to further improve the impurity removal effect of low-temperature steam; and the coverage range of the spray liquid sprayed by the spray unit is not less than the cross-sectional area of the tower section where the spray unit is located, so as to ensure the spraying effect of the spray unit on the low-temperature steam.

[0062] It's important to understand that hydrofluorosilicic acid, also known as hydrosilicofluoric acid, is a colorless, transparent, fuming liquid in aqueous solution. It is corrosive and can attack glass, so it should be stored in wax or plastic containers. Upon boiling, the aqueous solution readily decomposes into silicon tetrafluoride and hydrogen fluoride. Upon cooling, the concentrated solution precipitates colorless dihydrate crystals with a melting point of 19°C. Fluorosilicic acid can be used to produce fluorosilicates and cryolite, and is also used in electroplating, beer disinfection, and wood preservation.

[0063] It is also important to understand that fluorosilicic acid is primarily a byproduct of the phosphate fertilizer and anhydrous hydrogen fluoride industries. The current development and utilization of fluorosilicic acid primarily results in the production of low-value-added cryolite and aluminum fluoride. The production of high-quality, high-value-added hydrofluoric acid is still in the technological development stage. Due to its low concentration, most of the low-concentration fluorosilicic acid produced as a byproduct of phosphate fertilizer companies is not recycled but directly diluted and discharged with water, polluting the environment and wasting precious fluorine resources. Currently, the mainstream hydrofluoric acid production process on the market is still based on the fluorite process, which accounts for over 80% of total production. The fluorite process for producing hydrofluoric acid has high production costs and places significant environmental pressure. Furthermore, my country's fluorite reserve-to-production ratio has been declining year by year, falling to 10.5 in 2021, far below the global average of 45. Therefore, considering the prospects and full utilization of fluorine resources, it is necessary to improve the utilization rate of fluorine resources in the phosphate fertilizer industry and develop a device for concentrating fluorosilicic acid.

[0064] like Figure 1 The fluosilicic acid concentration device 100 according to an embodiment of the present invention can be used to concentrate fluosilicic acid and recycle the low-temperature steam generated by the concentration of fluosilicic acid to improve energy utilization.

[0065] Specifically, the concentration device 100 includes a concentration tower 20, a gas-liquid-solid separator 50, a forced circulation heat exchanger (i.e., the aforementioned heat exchanger 40), a gas-liquid separator 60, a steam compressor (i.e., the aforementioned gas heater 30), a feed pump (i.e., the aforementioned first pump assembly 91), and a circulation pump (i.e., the aforementioned second pump assembly 92). The feed pump's inlet is adapted to connect to a mother liquid tank (i.e., the aforementioned liquid storage source 10), which is used to store mother liquid.

[0066] Concentration tower 20 is lined with steel and sprayed with PFA. It features three internal spray stages and a demister. The three-stage spraying process consists of three layers of spiral spray heads (top, middle, and bottom), each of which produces a mist that covers the cross-section of that layer. Heating 18%-23% fluorosilicic acid produces low-temperature steam and a very small amount of hydrogen fluoride and silica. These are then flushed back into the tower via a three-stage spraying of the mother liquor. The low-temperature steam passes through the second demister 70 at the top of the tower before entering the gas-liquid-solid separator 50. The gas-liquid-solid separator 50 utilizes interception (packing layer), filtration (filter screen), and de-mist (wire mesh demister) to prevent any residual hydrogen fluoride and silica from entering the compressor after the three-stage spraying and de-misting process in concentrator 20.

[0067] The clean, filtered, low-temperature gas is compressed by the compressor into high-temperature gas. Preferably, the compressor is a diaphragm compressor, where the cylinder head and diaphragm are designed to allow a small amount of liquid to enter. This ensures stable operation even when the low-temperature steam is not fully filtered.

[0068] The shell side of the forced circulation heater is connected to the steam compressor, and the tube side is circulated by a circulating pump, heating the material in the concentrated column 20 in the forced circulation heater. After the low-temperature steam discharged from the shell side of the forced circulation heater undergoes gas-liquid separation, the gas returns to the front end of the compressor for reuse. The steam circulation heating continuously evaporates the water vapor in the low-concentration fluorosilicic acid, while the compressor continuously extracts the volatile water vapor from the top, thereby achieving the purpose of concentration.

[0069] In actual operation, the concentrator 20 is lined with steel and sprayed with PFA. The primary internal medium initially consists of 18%-23% fluorosilicic acid at an operating temperature of 40°C-50°C. As steam heating begins, the circulation begins, raising the fluorosilicic acid concentration to 36%-40%. After passing online testing, the circulating pump extracts the fluorosilicic acid and sends it to the next process. Furthermore, the circulating heat exchanger 40 is configured as a one-in-one backup unit. If one circulating heat exchanger 40 fails, it can be switched to the other, maintaining continuous operation of the concentrator 100. The circulating heat exchanger 40 is made of silicon carbide, which offers excellent high-temperature and corrosion resistance, ensuring optimal operation while heating the convection flowing through it.

[0070] It should be understood that, in the concentration tower 20, if the temperature of the fluorosilicic acid is too high, the fluorosilicic acid will decompose to produce hydrogen fluoride and silicon tetrafluoride, and the silicon tetrafluoride will react with water to produce fluorosilicic acid and silicon dioxide.

[0071] The working process of the concentrating device 100 is as follows:

[0072] 18% of the fluosilicic acid in the mother liquor tank is continuously sprayed into the concentration tower 20 through a feed pump. The fluosilicic acid sprays the hydrogen fluoride and silicon tetrafluoride therein, leaving the hydrogen fluoride and silicon dioxide at the bottom of the tower; the water vapor enters the gas-liquid-solid separator 50 upward to separate a small amount of hydrogen fluoride and silicon dioxide mixed in the water vapor, the water vapor is heated by the compressor and enters the shell side of the forced heater to heat the fluosilicic acid in the forced heater tube side, the water vapor in the shell side is separated into condensed water and water vapor by the gas-liquid separator 60, and the water vapor continues to flow back to the compressor for heating, thereby completing the steam circulation heating; the fluosilicic acid is heated in the forced heater, and the high-temperature fluosilicic acid is refluxed to the concentration tower 20, and is further concentrated in the concentration tower 20, and the water vapor is continuously output upward to ensure the continuous output of water vapor and obtain high-concentration fluosilicic acid.

[0073] According to the fluorosilicic acid concentration device 100 of the embodiment of the present invention, the device utilizes the system's waste heat as much as possible and does not require an external heat source. The device is stable and can operate continuously. The heating process of fluorosilicic acid easily decomposes silicon tetrafluoride, and silicon tetrafluoride and water will continue to produce hydrofluoric acid and silicon dioxide. The device controls the system temperature to minimize the decomposition of fluorosilicic acid while also adding mother liquor flushing in key areas. This ensures that even if a small amount of hydrofluoric acid and silicon dioxide is produced, it will not affect other equipment and systems, ensuring the stable operation of the device.

[0074] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0075] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0076] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0077] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0078] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A fluosilicic acid concentration device, characterized in that: include: A concentration tower, wherein the concentration tower is provided with a liquid inlet, a liquid outlet, a first reflux port, a gas outlet, and a second reflux port, wherein the liquid inlet is suitable for connecting to a liquid storage source capable of providing fluorosilicic acid; a gas heater, wherein the gas inlet end of the gas heater is connected to the gas outlet; a heat exchanger, the heat exchanger comprising a first heat exchange channel and a second heat exchange channel for mutually exchanging heat, wherein one end of the first heat exchange channel is connected to the gas outlet of the gas heater, and the other end is connected to the gas inlet of the gas heater, and one end of the second heat exchange channel is connected to the liquid outlet, and the other end is connected to the first return port; a gas-liquid-solid separator connected between the gas outlet and the gas inlet end of the gas heater, the gas-liquid-solid separator being provided with an inlet, a first outlet, a second outlet and a flushing port, the inlet being connected to the gas outlet, the first outlet being connected to the gas inlet end of the gas heater, and the second outlet being connected to the second reflux port, so that the gas-liquid-solid separator is used to separate the entrained silica and hydrofluoric acid, and the separated silica and hydrofluoric acid are suitable for being refluxed to the concentrator through the second reflux port; A first pump assembly, wherein the inlet end of the first pump assembly is suitable for connecting to the liquid storage source, the outlet end of the first pump assembly is connected to the flushing port, and the first pump assembly is used to drive the fluorosilicic acid in the liquid storage source to flow to the gas-liquid-solid separator to flush the silicon dioxide and hydrofluoric acid separated by the gas-liquid-solid separator.

2. The hydrosilicic acid concentration device according to claim 1, characterized in that: The gas heater is configured as a compressor.

3. The hydrosilicic acid concentration device according to claim 2, characterized in that: The compressor is a diaphragm compressor.

4. The fluosilicic acid concentration device according to claim 1, characterized in that: The outlet end of the first pump component is also connected to the liquid inlet, and the first pump component is used to drive the fluorosilicic acid in the liquid storage source to flow to the concentration tower.

5. The fluosilicic acid concentration device according to claim 1, characterized in that: The gas-liquid-solid separator includes a shell, a packing layer, a filter screen and a first demister. The packing layer, the filter screen and the first demister are all arranged in the shell. The shell is provided with an inlet and a first outlet. The inlet is connected to the air outlet, and the first outlet is connected to the air inlet end of the gas heater. The inlet and the first outlet are respectively provided with the filter screen. The first demister is spaced apart from the filter screen, and the packing layer is provided between the first demister and the filter screen.

6. The fluosilicic acid concentration device according to claim 1, characterized in that: The concentrating device further comprises: A gas-liquid separator is connected between the first heat exchange channel and the air inlet end of the gas heater.

7. The fluosilicic acid concentration device according to claim 1, characterized in that: The concentrating device further comprises a first pump assembly and a second pump assembly, wherein the first pump assembly is adapted to be connected between the liquid storage source and the liquid inlet, and the second pump assembly is connected between the liquid outlet and the second heat exchange channel; And / or, the liquid inlet and the liquid outlet are arranged at the lower part of the concentrating tower, the first reflux port is arranged at the middle part of the concentrating tower, and the gas outlet is arranged at the upper part of the concentrating tower; And / or, a second demister is provided at the air outlet.

8. The fluosilicic acid concentration device according to claim 1, characterized in that: There are multiple heat exchangers, and the first heat exchange channels of the multiple heat exchangers are connected in parallel between the gas outlet and the gas inlet of the gas heater, and the second heat exchange channels of the multiple heat exchangers are connected in parallel between the liquid outlet and the first return port. Any one of the multiple heat exchangers can be selectively connected or disconnected.

9. The device for concentrating fluorosilicic acid according to any one of claims 1 to 8, characterized in that: The concentrating device further comprises: A spray assembly and a first pump assembly, wherein the inlet end of the first pump assembly is suitable for connecting to the liquid storage source, the outlet end of the first pump assembly is connected to the spray assembly, and the first pump assembly is used to drive the fluorosilicic acid in the liquid storage source to flow to the spray assembly, and the spray assembly is arranged in the concentration tower and is used to spray the gas flowing toward the gas outlet.

10. The fluosilicic acid concentration device according to claim 9, characterized in that: The concentration tower includes a first tower section and a second tower section, the first tower section is arranged on the upper side of the second tower section, and the cross-sectional area of the first tower section is smaller than the cross-sectional area of the second tower section, the gas outlet is formed at the top of the first tower section, the spray assembly is arranged in the first tower section and is located below the gas outlet, the spray assembly includes a plurality of spray units arranged at intervals from top to bottom, and each of the spray units includes at least one spiral nozzle.

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