A tail gas treatment system

Abstract

The application relates to the tail gas treatment technical field, in particular to a tail gas treatment system, which comprises a condensing device, a compression device, a heat exchange device and an absorption tower. The condensing device is provided with a tail gas inlet, and the condensing device separates the tail gas to form gas phase materials and liquid phase materials; the gas inlet of the compression device is connected with the gas phase outlet of the condensing device; the heat exchange device is provided with a first channel and a second channel, the inlet end of the first channel is connected with the exhaust port of the compression device, the inlet end of the second channel is connected with the liquid phase outlet of the condensing device, and the liquid phase materials exchange heat with the gas phase materials in the first channel after entering the second channel; the first feeding port of the absorption tower is connected with the outlet end of the first channel, and the absorption tower absorbs the first component in the gas phase materials so that the second component in the gas phase materials is discharged. The gas phase materials and the liquid phase materials exchange heat in the heat exchange device, the waste heat utilization rate of the tail gas treatment process is improved, and the energy loss in the polysilicon production process is reduced.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology, and in particular to an exhaust gas treatment system. Background Technology

[0002] In the polysilicon production process, the purification of chlorosilane tail gas and the distillation of materials are core production steps. Among them, the tail gas compression and transportation and the low-temperature material distillation and purification processes involve a large amount of energy waste. In the polysilicon production system, the tail gas, after being pretreated by low-temperature condensation at the front end, needs to be fed into a compressor for pressurization and transportation. During the compression process of the gas in the compressor, a large amount of heat is generated, which makes the temperature of the tail gas discharged from the compressor reach 100-115℃, forming a large amount of high-temperature waste heat tail gas.

[0003] In existing polysilicon production processes, the high-temperature exhaust gas discharged from the compressor is mostly treated by direct cooling, resulting in a significant loss of waste heat and serious energy waste. Furthermore, the low-temperature chlorosilane material condensed in the low-pressure zone during polysilicon production needs to be sent to a distillation column for component purification. The reboiler at the bottom of the distillation column requires a large amount of steam heat source to heat and vaporize the low-temperature chlorosilane material to meet the process requirements of distillation separation, leading to severe energy loss during polysilicon production. Summary of the Invention

[0004] This application provides a waste heat recovery system for polycrystalline silicon exhaust gas compressors to solve the problem of severe energy loss during polycrystalline silicon production.

[0005] This application provides an exhaust gas treatment system, including:

[0006] The condensation unit has an exhaust gas inlet;

[0007] The condensation unit is configured to condense the exhaust gas entering from the exhaust gas inlet and separate the components in the exhaust gas into gaseous and liquid phase materials.

[0008] The compressor unit has its air inlet connected to the gas phase outlet of the condenser unit.

[0009] The heat exchange device has a first channel and a second channel. The inlet end of the first channel is connected to the exhaust port of the compression device, and the inlet end of the second channel is connected to the liquid phase outlet of the condensation device, so that the liquid phase material can exchange heat with the gas phase material in the first channel after entering the second channel, thereby cooling the gas phase material.

[0010] The absorption tower has its first feed inlet connected to the outlet of the first channel. The absorption tower is constructed to absorb the first component in the gaseous material so that the second component in the gaseous material is discharged from the exhaust port of the absorption tower.

[0011] In one possible embodiment, a resolution tower is also included, the inlet of which is connected to the outlet of the second channel.

[0012] In one possible embodiment, the gaseous material after heat exchange enters the absorption tower, absorbs the first component in the absorption tower to form a mixed liquid phase, and the outlet of the absorption tower is used to discharge the mixed liquid phase.

[0013] The inlet of the analytical column is connected to the outlet of the absorption column;

[0014] The analytical column is constructed to analyze the mixed liquid phase to separate the first component and the liquid phase material;

[0015] The first outlet of the stripping column is used to discharge the first component, and the second outlet of the stripping column is used to discharge the liquid phase material.

[0016] In one possible embodiment, a reflux pipe is also included, through which the second outlet of the analytical tower is connected to the absorption tower.

[0017] In one possible embodiment, the heat exchange device is configured to allow the gaseous material in the first channel to flow in opposite directions to the liquid material in the second channel.

[0018] In one possible embodiment, the heat exchange device has a first side and a second side arranged opposite to each other, with the inlet end of the first channel and the outlet end of the second channel located on the first side of the heat exchange device, and the outlet end of the first channel and the inlet end of the second channel located on the second side of the heat exchange device.

[0019] In one possible embodiment, the heat exchange device includes a heat exchange shell and heat exchange tubes;

[0020] The heat exchange tube is installed inside the heat exchange shell, and a first channel for gas phase material transport is formed between the heat exchange tube and the heat exchange shell.

[0021] The heat exchange tube has a second channel for transporting liquid materials.

[0022] In one possible embodiment, the central axis of the heat exchange shell coincides with the central axis of the heat exchange tube.

[0023] In one possible embodiment, the heat exchange device has a plurality of heat exchange sections along its length direction. Each heat exchange section has a first flow channel section and a second flow channel section. Along the length direction of the heat exchange device, the first flow channel sections of each heat exchange section are connected in sequence to form a first channel, and the second flow channel sections of each heat exchange section are connected in sequence to form a second channel.

[0024] In one possible embodiment, the exhaust gas is polysilicon exhaust gas, which includes hydrogen, hydrogen chloride, and chlorosilane.

[0025] The gaseous phase materials include hydrogen and hydrogen chloride, and the liquid phase materials include liquid chlorosilanes.

[0026] The exhaust gas treatment system provided in this application embodiment condenses and separates the exhaust gas into gaseous and liquid phase materials through a condensation device. The gaseous material is compressed by a compression device and then exchanges heat with the liquid phase material in a heat exchange device. The condensed and separated liquid phase material cools the gaseous material that has been compressed and heated by the compression device. Furthermore, the compressed and heated gaseous material heats the liquid phase material that has been condensed and separated by the condensation device, thereby meeting the requirements of the absorption tower for the feed state and realizing the absorption and separation of the first component and the discharge of the second component in the gaseous material. This improves the waste heat utilization rate of the exhaust gas treatment process and reduces the energy consumption in the polysilicon production process. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0028] Figure 1 A schematic diagram of the exhaust gas treatment system provided in this application;

[0029] Figure 2 A schematic diagram of the heat exchange device provided in this application;

[0030] Figure 3 A cross-sectional view of the heat exchange device provided in this application;

[0031] Figure 4 A cross-sectional view of the heat exchange section provided in this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 100-Condensation device; 200-Compression device; 300-Heat exchange device; 310-Heat exchange shell; 320-Heat exchange tube; 330-First channel; 340-Second channel; 350-Heat exchange section; 351-First flow channel section; 352-Second flow channel section; 400-Absorption tower; 500-Desorption tower; 600-Reflux pipe; 700-Adsorption column.

[0034] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0036] This application relates to the field of exhaust gas treatment technology, and is applicable to the treatment of polycrystalline silicon exhaust gas containing chlorosilane, hydrogen and hydrogen chloride in the condensation separation, compression and subsequent purification process. The exhaust gas is first treated by a front-end condensation device to separate gaseous and liquid phase materials. Then the gaseous material in the exhaust gas is compressed. During the compression work, a large amount of compression heat is generated, so that the temperature of the discharged exhaust gas can reach 100-115°C, forming a large amount of high-temperature waste heat exhaust gas. The high-temperature waste heat exhaust gas is cooled and then absorbed to meet the requirements for exhaust gas recovery and emission.

[0037] In existing exhaust gas treatment systems, a common practice is to send the gaseous stream obtained after condensation of the exhaust gas into a compression device for pressurization, then cool the high-temperature gaseous material after compression using an air cooler or water cooler, and finally send it to an absorption tower for absorption and separation of some components in the exhaust gas. However, direct cooling results in a large amount of waste heat being directly lost, causing serious energy waste. Furthermore, in the polysilicon production process, the low-temperature chlorosilane material condensed in the low-pressure zone needs to be sent to a distillation tower for component purification, which requires a large amount of steam heat source to heat and vaporize the low-temperature chlorosilane material to meet the process requirements of distillation separation, resulting in serious energy loss in the polysilicon production process.

[0038] To address the aforementioned problems, an exhaust gas treatment system is provided, comprising a condensation unit 100, a compression unit 200, a heat exchange unit 300, and an absorption tower 400. The condensation unit 100 has an exhaust gas inlet and is configured to condense the exhaust gas entering from the exhaust gas inlet, separating the components in the exhaust gas into gaseous and liquid phase materials. The inlet of the compression unit 200 is connected to the gas phase outlet of the condensation unit 100. The heat exchange unit 300 has a first channel 330 and a second channel 340. The inlet of the first channel 330 is connected to the exhaust port of the compression device 200, and the inlet of the second channel 340 is connected to the liquid phase outlet of the condensation device 100, so that the liquid phase material can exchange heat with the gas phase material in the first channel 330 after entering the second channel 340, thereby cooling the gas phase material; the first feed port of the absorption tower 400 is connected to the outlet of the first channel 330, and the absorption tower 400 is constructed to absorb the first component in the gas phase material, so that the second component in the gas phase material is discharged from the exhaust port of the absorption tower 400. After the tail gas is condensed and separated by the condensation device 100, gaseous and liquid phase materials are obtained. The gaseous material is compressed and then exchanges heat with the liquid phase material in the heat exchange device 300. The condensed and separated liquid phase material cools the compressed and heated gaseous material, and the compressed and heated gaseous material heats the condensed and separated liquid phase material. This satisfies the requirements of the absorption tower 400 for the feed state and realizes the absorption and separation of the first component in the gaseous material and the discharge of the second component, thereby improving the waste heat utilization rate of the tail gas treatment process and reducing the energy consumption in the polysilicon production process.

[0039] This application provides an exhaust gas treatment system, referring to... Figure 1 and Figure 3 As shown, the device includes a condenser 100, a compressor 200, a heat exchanger 300, and an absorber 400. The condenser 100 has a tail gas inlet and is configured to condense the tail gas entering from the tail gas inlet, separating the components in the tail gas into gaseous and liquid phase materials. The inlet of the compressor 200 is connected to the gas phase outlet of the condenser 100. The heat exchanger 300 has a first channel 330 and a second channel 340. The inlet end of the first channel 330 is connected to the exhaust port of the compressor 200, and the inlet end of the second channel 340 is connected to the liquid phase outlet of the condenser 100, so that the liquid phase material entering the second channel 340 can exchange heat with the gaseous material in the first channel 330 to cool the gaseous material. The first feed inlet of the absorber 400 is connected to the outlet end of the first channel 330. The absorber 400 is configured to absorb the first component in the gaseous material, so that the second component in the gaseous material is discharged from the exhaust port of the absorber 400.

[0040] The condensing device 100 is installed at the front end of the exhaust gas treatment system and is used to cool the exhaust gas and achieve gas-liquid separation, separating the condensable components in the exhaust gas from the gas to form gaseous and liquid materials.

[0041] Furthermore, the exhaust gas inlet of the condensing device 100 is connected to the exhaust gas delivery pipeline, the gas phase outlet of the condensing device 100 is connected to the air inlet of the compression device 200, and the liquid phase outlet of the condensing device 100 is connected to the inlet end of the second channel 340 of the heat exchange device 300, thereby forming a continuous fluid transfer path.

[0042] The compression device 200 is installed after the gas phase outlet of the condensation device 100 and is used to pressurize and transport the condensed gas phase material, raising the low-pressure gas phase material from the condensation device 100 to the pressure conditions required for subsequent heat exchange and absorption processes.

[0043] Furthermore, the air inlet of the compression device 200 is connected to the gas phase outlet of the condensation device 100, and the exhaust port of the compression device 200 is connected to the inlet end of the first channel 330 of the heat exchange device 300, so that the gas phase material enters the heat exchange stage after compression is completed.

[0044] The heat exchange device 300 has a first channel 330 and a second channel 340 that are isolated from each other. It is a heat exchange component used to indirectly exchange heat between liquid material and compressed gaseous material. The liquid material cools the compressed gaseous material, and the liquid material absorbs the heat energy of the gaseous material to realize heat exchange between the liquid material and the compressed gaseous material, thereby realizing the heating of the liquid material and the cooling of the compressed gaseous material.

[0045] Furthermore, the inlet end of the first channel 330 is connected to the exhaust port of the compression device 200, and the outlet end of the first channel 330 is connected to the first feed port of the absorption tower 400; the inlet end of the second channel 340 is connected to the liquid phase outlet of the condensation device 100, and the first channel 330 and the second channel 340 are structurally designed to ensure that the liquid phase material and the compressed gas phase material achieve heat transfer through the heat exchange wall.

[0046] The absorption tower 400 is a tower-type device located downstream of the heat exchange device 300, used for component absorption and separation of cooled gaseous materials. The first component in the gaseous material is captured by the absorption medium, and the remaining second component is discharged through the exhaust port of the absorption tower 400.

[0047] Furthermore, the first feed inlet of the absorption tower 400 is connected to the outlet end of the first channel 330 to receive the cooled gaseous material, and the exhaust port of the absorption tower 400 is used to discharge the second component that has not been absorbed.

[0048] Furthermore, the exhaust port of the absorption tower 400 is connected to an adsorption column 700 to facilitate further separation of the remaining second component.

[0049] The exhaust gas treatment system provided in this application embodiment first enters the condenser 100 and is cooled under the action of the heat exchange medium. The condensable components are separated into liquid phase materials and discharged from the liquid phase outlet. The uncondensed gas, as gas phase materials, enters the compressor 200 through the gas phase outlet to complete the pressurization. The compressed gas phase materials, carrying the heat of compression, enter the first channel 330 of the heat exchanger 300. The liquid phase materials output from the condenser 100 enter the second channel 340. Furthermore, the liquid phase materials in the second channel 340 and the high-temperature gas phase materials in the first channel 330 form an indirect heat exchange, thereby cooling the gas phase materials to a state suitable for absorption and separation before entering the absorption tower 400. When the gas phase materials enter the absorption tower 400, the absorption medium and the gas phase materials are in full contact inside the absorption tower 400. The first component in the gas phase materials is absorbed, and the unabsorbed second component is discharged through the exhaust port of the absorption tower 400. By exchanging heat between the compressed gaseous material and the liquid material in the heat exchanger 300, the liquid material after condensation and separation cools the compressed and heated gaseous material, and the compressed and heated gaseous material heats the liquid material. This achieves heat energy exchange between the liquid material and the compressed and heated gaseous material, improving the waste heat utilization rate of the tail gas treatment process and reducing energy loss in the polysilicon production process. As a result, the tail gas treatment system can maintain stable tail gas treatment while meeting the feeding conditions of the absorption tower 400.

[0050] In one possible implementation, based on the foregoing embodiments, referring to Figure 1 and Figure 3 As shown, it also includes a stripping tower 500, the inlet of which is connected to the outlet of the second channel 340. The inlet of the stripping tower 500 is a material inlet for introducing the heat-exchanged liquid material, and the liquid material flowing out of the second channel 340 is fed into the stripping tower 500, allowing the liquid material to undergo stripping within the tower to separate the first component and the liquid material.

[0051] Furthermore, the inlet of the analytical tower 500 and the outlet of the second channel 340 can be connected by a pipe, a flange, or by welding. As long as the second channel 340 is connected to the analytical tower 500, the liquid material can enter the absorption tower 400 under gravity, self-pressure, or pumping.

[0052] The exhaust gas treatment system provided in this application embodiment involves a heat exchange process between the liquid phase material in the second channel 340 and the gaseous material in the first channel 330. Due to the increased temperature of the gaseous material after compression, the high-temperature gaseous material transfers heat to the condensed liquid phase material. The liquid phase material, carrying some of the heat transferred by the gaseous material, enters the inlet of the desorption tower 500 through the outlet of the second channel 340. Since the inlet of the desorption tower 500 is connected to the outlet of the second channel 340, the liquid phase material enters the contact area within the desorption tower 500 and undergoes desorption within the tower to separate the first component and the liquid phase material. By introducing the heat-exchanged liquid phase material as an absorption medium into the desorption tower 500, the heat carried by the liquid phase material and its absorption capacity are fully utilized to achieve the separation of the first component and the liquid phase material.

[0053] In one possible implementation, based on the foregoing embodiments, referring to Figure 1 and Figure 3 As shown, the gaseous material after heat exchange enters the absorption tower 400, where the first component is absorbed to form a mixed liquid phase. The outlet of the absorption tower 400 is used to discharge the mixed liquid phase. The inlet of the desorption tower 500 is connected to the outlet of the absorption tower 400. The desorption tower 500 is constructed to desorb the mixed liquid phase to separate the first component and the liquid material. The first outlet of the desorption tower 500 is used to discharge the first component, and the second outlet of the desorption tower 500 is used to discharge the liquid material.

[0054] Among them, the desorption tower 500 is a vertical tower device used to desorb and separate the mixed liquid phase entering the absorption tower 400, so that the first component in the mixed liquid phase is desorbed from the mixed liquid phase, thereby realizing the separation of the first component from the liquid phase material.

[0055] Furthermore, the stripping tower 500 is responsible for reprocessing the enriched mixed liquid phase discharged from the absorption tower 400, releasing and recovering the first component carried or absorbed by the liquid phase during the absorption process, so as to facilitate the recycling or discharge of the liquid phase material.

[0056] Furthermore, the inlet of the analytical tower 500 can be located in the lower middle part of the analytical tower 500 or at the top of the analytical tower 500, and is connected to the outlet of the absorption tower 400 through a pipe. The mixed liquid phase discharged from the outlet of the absorption tower 400 enters the interior of the analytical tower 500.

[0057] Furthermore, the first outlet of the analytical tower 500 can be located at the top of the analytical tower 500 or near the top of the analytical tower 500, for discharging the first component gas after analytical enrichment.

[0058] Furthermore, the second outlet of the analytical column 500 can be located at the bottom of the analytical column 500 or near the bottom of the analytical column 500, for discharging the analytical liquid material.

[0059] Specifically, the analytical tower 500 can be a packed tower, a plate tower, a spray tower, or a composite tower structure.

[0060] The exhaust gas treatment system provided in this application embodiment involves a mixed liquid phase discharged from the bottom of the absorption tower 400 entering the inlet of the desorption tower 500 under gravity or pumping. Within the desorption tower 500, the absorbed first component is desorbed and migrates upwards, then exits from the first outlet of the desorption tower 500. The liquid phase material after the first component is removed continues to flow downwards within the desorption tower 500 and collects at the second outlet, thus achieving the recovery and reuse of the first component. The desorption tower 500 further separates the mixed liquid phase discharged from the absorption tower 400, reducing the residual amount of the first component and enabling its recovery and reuse.

[0061] In one possible implementation, refer to Figure 1 and Figure 3 As shown, it also includes a reflux pipe 600, and the second outlet of the analytical tower 500 is connected to the absorption tower 400 through the reflux pipe 600.

[0062] The reflux pipe 600 is a pipeline component used to transport the liquid material discharged from the second outlet of the desorption tower 500 back to the absorption tower 400, so that the liquid material obtained after separation in the desorption tower 500 returns to the absorption tower 400 to participate in the absorption cycle again, thereby improving the absorption and utilization rate of the first component.

[0063] Furthermore, the reflux pipe 600 is installed between the second outlet of the desorption tower 500 and the liquid inlet of the absorption tower 400, so that the desorbed liquid phase material enters the absorption tower 400 under gravity, pumping or differential pressure drive.

[0064] Specifically, the reflux pipe 600 can be connected to the absorption tower 400 and the desorption tower 500 by flange, thread, or welding, as long as a sealed fit is achieved between the reflux pipe 600 and the absorption tower 400 and the desorption tower 500.

[0065] Specifically, a shut-off valve, a check valve, or a flow regulating valve can be installed on the return pipe 600 to adjust the return flow rate in the return pipe 600 and prevent material backflow.

[0066] The exhaust gas treatment system provided in this application embodiment includes a mixed liquid phase discharged from the bottom of the absorption tower 400, which enters the inlet of the desorption tower 500 under gravity or pumping. The desorption occurs within the desorption tower 500, causing the first component absorbed in the mixed liquid phase to separate from the mixed liquid phase and migrate upwards, before being discharged from the first outlet of the desorption tower 500. Furthermore, the liquid phase material after the first component is removed continues to flow downwards within the desorption tower 500, and the liquid phase material discharged from the second outlet of the desorption tower 500 is returned to the absorption tower 400 via the reflux pipe 600, thereby achieving the recovery of the first component and the reuse of the liquid phase material. Additionally, the mixed liquid phase formed at the bottom of the absorption tower 400 enters the desorption tower 500 for further desorption through the outlet of the absorption tower 400. The liquid phase material separated by the desorption tower 500 is then returned to the absorption tower 400 via the reflux pipe 600, forming a closed liquid circulation loop. The return pipe 600 facilitates the return of the liquid material after analysis by the analysis tower 500 to the absorption tower 400, thereby realizing the recovery and reuse of the liquid material and the first component, improving the recovery efficiency of the first component and the liquid material, and reducing the energy loss during the operation of the tail gas treatment system.

[0067] In one possible implementation, based on the foregoing embodiments, referring to Figure 2 and Figure 3 As shown, the heat exchange device 300 is configured to allow the gaseous material in the first channel 330 to flow in opposite directions to the liquid material in the second channel 340.

[0068] The reverse flow arrangement refers to the arrangement of the first channel 330 and the second channel 340 of the heat exchange device 300 along opposite flow directions, so that the high-temperature gaseous material and the low-temperature liquid material pass continuously in opposite directions in the heat exchange area, thereby forming a more uniform heat exchange state, which can improve the waste heat recovery efficiency of the compressed gaseous material and reduce the air cooling or water cooling energy consumption required for the gaseous material before entering the absorption tower 400.

[0069] Furthermore, the heat exchange device 300 may include a housing, on which a first channel 330 and a second channel 340 are provided. Both the first channel 330 and the second channel 340 have an inlet end and an outlet end. The gaseous material in the first channel 330 enters along the inlet end of the first channel 330, flows in a first direction, and is discharged from the outlet end of the first channel 330. The liquid material in the second channel 340 enters along the inlet end of the second channel 340 opposite to the outlet end of the first channel 330, and flows in a direction opposite to the first direction, so that the high-temperature gaseous material and the condensed liquid material form opposing heat transfer on both sides of the adjacent heat exchange surface.

[0070] Specifically, the first channel 330 and the second channel 340 can be separated and guided by plate heat exchange plates, shell-and-tube heat exchange tube bundles 320, spiral channels or baffles to ensure that the high-temperature gas phase material and the condensed liquid phase material can easily exchange heat and do not mix with each other.

[0071] Specifically, the first channel 330 can also be arranged as a tube-side or plate-side flow channel, and the second channel 340 can also be arranged as a shell-side, adjacent plate-side flow channel, or tube-side flow channel. The inlet end of the first channel 330 is usually located on one side of the heat exchange device 300, while the inlet end of the second channel 340 is located on the opposite side of the inlet end of the first channel 330, so as to realize countercurrent heat exchange in the heat exchange device 300.

[0072] The exhaust gas treatment system provided in this application embodiment first pressurizes the gaseous material in the compression device 200. The high-temperature gaseous material after compression enters the first channel 330 through the inlet end of the first channel 330 and flows in the first direction. Meanwhile, the liquid material enters the second channel 340 through the inlet end of the second channel 340 and passes through the second channel 340 in the opposite direction. During this process, the liquid material continuously absorbs the heat of the high-temperature gaseous material in the first channel 330, thereby cooling the gaseous material to a temperature suitable for subsequent absorption and treatment. The liquid material is preheated and enters the absorption tower 400. The gaseous material after heat exchange is transported to the first feed port of the absorption tower 400 through the outlet end of the first channel 330, and the liquid material at the outlet end of the second channel 340 enters the absorption tower 400 through the second feed port of the absorption tower 400. By setting the first channel 330 and the second channel 340 to flow in opposite directions, the temperature difference impact during the heat exchange process is reduced, thereby forming a more uniform heat exchange state. This is to improve the waste heat recovery efficiency of the compressed gaseous material and reduce the air cooling or water cooling energy consumption required for the gaseous material before it enters the absorption tower 400.

[0073] In one possible implementation, refer to Figure 2 and Figure 3 As shown, the heat exchange device 300 has a first side and a second side arranged opposite to each other. The inlet end of the first channel 330 and the outlet end of the second channel 340 are located on the first side of the heat exchange device 300, and the outlet end of the first channel 330 and the inlet end of the second channel 340 are located on the second side of the heat exchange device 300.

[0074] The inlet end of the first channel 330 and the outlet end of the second channel 340 are located on one side of the heat exchange device 300, the outlet end of the first channel 330 and the inlet end of the second channel 340 are located on the other side of the heat exchange device 300, and the inlet end of the first channel 330 and the outlet end of the first channel 330 are located on opposite sides of the heat exchange device 300.

[0075] Furthermore, both the first side and the second side are side walls of the heat exchange device 300. In this application, the first side and the second side are respectively set as opposite side walls of the heat exchange device 300.

[0076] Furthermore, since the inlet end of the first channel 330 and the outlet end of the second channel 340 are located on one side of the heat exchange device 300, and the outlet end of the first channel 330 and the inlet end of the second channel 340 are located on opposite sides of the heat exchange device 300, the gaseous material in the first channel 330 and the liquid material in the second channel 340 flow in opposite directions.

[0077] The exhaust gas treatment system provided in this application embodiment has its inlet end of the first channel 330 and the inlet end of the second channel 340, as well as the outlet end of the first channel 330 and the outlet end of the second channel 340, facing each other to achieve counter-current flow of materials in the first channel 330 and the second channel 340, thereby achieving uniform heat exchange. This facilitates the improvement of the waste heat recovery efficiency of the compressed gaseous material and reduces the air cooling or water cooling energy consumption required for the gaseous material before entering the absorption tower 400.

[0078] In one possible implementation, based on the foregoing embodiments, referring to Figure 2 and Figure 3 As shown, the heat exchange device 300 includes a heat exchange shell 310 and a heat exchange tube 320; the heat exchange tube 320 is disposed inside the heat exchange shell 310, and a first channel 330 for gas phase material transportation is formed between the heat exchange tube 320 and the heat exchange shell 310; the heat exchange tube 320 has a second channel 340 for liquid phase material transportation.

[0079] The heat exchange shell 310 is a pressure-bearing shell component used to accommodate and define the heat exchange space; the heat exchange tube 320 is a tubular heat exchange component arranged inside the heat exchange shell 310 and forming an inner and outer dual-channel heat exchange path, providing a flow channel for the gaseous material from the compression device 200 and the liquid material from the condensation device 100 to be isolated from each other and to transfer heat to each other, so that the high-temperature gaseous material and the condensed liquid material can complete the heat exchange without direct mixing.

[0080] Furthermore, after the heat exchange tube 320 is installed in the inner cavity of the heat exchange shell 310, the outer wall of the heat exchange tube 320 and the inner wall of the heat exchange shell 310 form a first channel 330. The gaseous material enters the first channel 330 along the exhaust port of the compression device 200 and exchanges heat with the liquid material in the second channel 340 on the outside of the heat exchange tube 320.

[0081] Furthermore, the second channel 340 formed inside the heat exchange tube 320 is used for liquid phase material transportation. After the liquid phase material enters the second channel 340 along the liquid phase outlet of the condensing device 100, it flows axially inside the heat exchange tube 320 and absorbs heat from the high-temperature gas phase material.

[0082] Specifically, the heat exchange shell 310 and the heat exchange tube 320 can be cylindrical shell-and-tube structures, tube-and-shell structures, or multi-tube bundle structures.

[0083] Specifically, the second channel 340 of the heat exchange tube 320 can be a single-tube straight-through channel, a multi-tube straight-through channel, or a spiral channel.

[0084] The exhaust gas treatment system provided in this application embodiment uses a first channel 330 formed between the heat exchange shell 310 and the heat exchange tube 320, and a second channel 340 formed inside the heat exchange tube 320, to isolate the high-temperature gaseous material from the condensed liquid material. While ensuring the continuous flow of the high-temperature gaseous material and the condensed liquid material, the system achieves mutual isolation between the high-temperature gaseous material and the condensed liquid material, thereby realizing the heat energy exchange between the high-temperature gaseous material and the condensed liquid material.

[0085] In one possible implementation, refer to Figure 2 and Figure 3 As shown, the central axis of the heat exchange shell 310 coincides with the central axis of the heat exchange tube 320.

[0086] The central axis of the heat exchange shell 310 coincides with the central axis of the heat exchange tube 320. This means that the heat exchange tube 320 is arranged along the geometric center of the heat exchange shell 310, so that the two are coaxial in the axial direction. This makes the gaseous material flowing between the outer wall of the heat exchange tube 320 and the inside of the heat exchange shell 310 flow more uniformly around the outer periphery of the heat exchange tube 320, thereby making the liquid material flowing inside the heat exchange tube 320 undergo uniform heat exchange.

[0087] Furthermore, the heat exchange shell 310 can be a cylindrical shell or a cylindrical shell, in order to improve the uniform heat exchange performance between gaseous and liquid materials.

[0088] Specifically, the central axis of the heat exchange shell 310 refers to the rotation center line formed by the rotation of the heat exchange shell 310 cylinder; if the shell is a cylindrical cylinder, it is the geometric central axis of the cylinder, and extends along the length of the shell.

[0089] Furthermore, the heat exchange tube 320 can be a straight tube or a spiral tube, as long as the heat exchange tube 320 and the heat exchange shell 310 are coaxially arranged to improve the uniformity of fluid heat exchange and make the gaseous material in the first channel 330 more uniformly distributed along the circumference of the heat exchange shell 310.

[0090] Specifically, the central axis of the heat exchange tube 320 refers to the geometric center line of rotation formed by the rotation of the tube wall of the heat exchange tube 320, and extends along the length of the heat exchange tube 320.

[0091] Specifically, the heat exchange shell 310 and the heat exchange tube 320 can be fixedly connected by a positioning ring, a guide sleeve, or multiple connecting rods distributed circumferentially along the heat exchange tube 320, as long as the coaxial connection between the heat exchange tube 320 and the heat exchange shell 310 is ensured.

[0092] The exhaust gas treatment system provided in this application embodiment, by aligning the central axis of the heat exchange shell 310 with the central axis of the heat exchange tube 320, ensures that the gaseous material is evenly distributed on the outer periphery of the heat exchange tube 320, thereby uniformly transferring heat energy to the liquid material inside the heat exchange tube 320. This promotes the effective transfer of heat energy from the high-temperature gaseous material to the condensed liquid material, improving the heat exchange efficiency and the uniformity of heat transfer.

[0093] In one possible implementation, refer to Figure 3 and Figure 4 As shown, the heat exchange device 300 has a plurality of heat exchange sections 350 along its own length direction. Each heat exchange section 350 has a first flow channel section 351 and a second flow channel section 352. Along the length direction of the heat exchange device 300, the first flow channel sections 351 of each heat exchange section 350 are connected in sequence to form a first channel 330, and the second flow channel sections 352 of each heat exchange section 350 are connected in sequence to form a second channel 340.

[0094] Among them, the heat exchange section 350 is a local functional segment that constitutes a continuous heat exchange unit in the length direction of the heat exchange device 300. Each heat exchange section 350 corresponds to a flow space in the first channel 330 and a flow space in the second channel 340, respectively, and is used to complete the heat transfer between gaseous material and liquid material in a local area.

[0095] Furthermore, by decomposing the heat exchange process into multiple heat exchange sections distributed in series, the gaseous and liquid materials entering the heat exchange device 300 can sequentially undergo multiple heat transfer stages along the length direction, thereby improving the uniformity of heat energy exchange and reducing the heat exchange load of a single section.

[0096] Specifically, the first flow channel section 351 and the second flow channel section 352 can be set as independent flow channel sections, and the flow channel sections can be connected in series through end connection ports, flow guide cavities or flow collection cavities. Alternatively, they can form an axially continuous multi-stage heat exchange structure through the segmented cooperation of the shell side and tube side.

[0097] The exhaust gas treatment system provided in this application divides the heat exchange device 300 into multiple heat exchange sections 350 along its length, and connects the first flow channel section 351 and the second flow channel section 352 of each heat exchange section 350 sequentially. This allows the gaseous and liquid phase materials to complete heat exchange in stages within a relatively long flow path, which is beneficial for fully recovering the heat in the compressed gaseous material and for gradually heating the liquid phase material without causing abrupt temperature differences, thereby improving the heat exchange stability between the gaseous and liquid phase materials. In addition, it facilitates the adjustment of the size and specifications of the heat exchange device 300 according to the site requirements of the exhaust gas treatment, and also facilitates the replacement of individual heat exchange sections 350 of the heat exchange device 300, improving the maintenance efficiency of the heat exchange device 300.

[0098] In one possible implementation, the exhaust gas is polycrystalline silicon exhaust gas, which includes hydrogen, hydrogen chloride, and chlorosilane; the gaseous material includes hydrogen and hydrogen chloride, and the liquid material includes liquid chlorosilane.

[0099] In this application, the exhaust gas typically originates from the mixed exhaust gas produced during the polysilicon production process. The mixed exhaust gas includes chlorosilane, hydrogen chloride, and hydrogen.

[0100] Among them, the gaseous materials include hydrogen and hydrogen chloride, and hydrogen and hydrogen chloride exist mainly in gaseous form at room temperature and pressure.

[0101] Furthermore, the gaseous material includes a first component and a second component, wherein the first component is hydrogen chloride and the second component is hydrogen gas.

[0102] The liquid phase material includes liquid chlorosilane, and after being cooled by the condenser 100, the liquid phase material exists in liquid form.

[0103] Furthermore, in this application, the liquid material can enter the absorption tower 400 through the second feed port, thereby absorbing the first component in the absorption tower 400 to form a mixed liquid phase. Specifically, the mixed liquid phase is a mixture of hydrogen chloride and chlorosilane, and the mixed liquid phase exists in liquid form.

[0104] The exhaust gas treatment system provided in this application embodiment first enters the condenser 100 for cooling and separation of polycrystalline silicon exhaust gas containing hydrogen, hydrogen chloride, and chlorosilane. After condensation, the resulting gaseous and liquid phase materials are obtained. The gaseous material is mainly composed of hydrogen and hydrogen chloride, while the liquid phase material is mainly composed of liquid chlorosilane. Subsequently, the gaseous material enters the compression device 200 to increase the pressure and temperature. The high-temperature compressed gaseous material is sent to the first channel 330 of the heat exchange device 300. At the same time, the condensed liquid phase material enters the heat exchange device 300 through the second channel 340 and exchanges heat with the gaseous material, causing the gaseous material to release heat and be cooled. Since the hydrogen and hydrogen chloride in the gaseous material have been pre-cooled before entering the absorption tower 400, the hydrogen chloride is more easily absorbed by the liquid phase material to form a mixed liquid phase. After absorbing heat, the temperature of the liquid phase material rises. The recovery of compression heat by the liquid chlorosilane reduces the external cooling load, enabling the exhaust gas treatment system to complete heat utilization without adding an additional cooling unit.

[0105] In the above detailed description, reference has been made to the accompanying drawings, which illustrate specific aspects of this disclosure by way of illustration. In this regard, terms indicating direction or positional relationship, such as “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential,” are used with reference to the orientation of the described figures. Since components of the described device can be positioned in multiple different orientations, directional terms are used for illustrative purposes and not for limitation. It should be understood that other aspects can be utilized and structural or logical changes can be made without departing from the concept of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0106] It should be understood that, unless otherwise expressly specified and limited, the terms "joining," "attaching," "installing," "connecting," "linking," "fixing," etc., used in the embodiments of this disclosure should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms herein based on the specific circumstances.

[0107] Furthermore, the term "above" as used herein with respect to components, elements, or material layers formed or located "above" a surface may be used to indicate that the component, element, or material layer is "indirectly" positioned (e.g., placed, formed, deposited, etc.) on the surface such that one or more additional components, elements, or layers are arranged between the surface and the component, element, or material layer. However, the term "above" as used with respect to components, elements, or material layers formed or located "above" a surface may also optionally have a specific meaning: that the component, element, or material layer is "directly" positioned (e.g., placed, formed, deposited, etc.) on the surface, for example, in direct contact with the surface.

[0108] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited to these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, part, region, layer, or section mentioned in the examples may also be referred to as the second component, part, region, layer, or section. 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 indicated technical features. Thus, a feature defined as “first” or “second” may explicitly or implicitly include at least one of that feature. In the description herein, “a plurality” means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0109] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. An exhaust gas treatment system, characterized in that, include: The condenser (100) has a tail gas inlet; The condensation device (100) is configured to condense the tail gas entering from the tail gas inlet and separate the components in the tail gas to form gaseous and liquid phase materials. A compression device (200) has its inlet connected to the gas phase outlet of the condenser (100); The heat exchange device (300) has a first channel (330) and a second channel (340). The inlet end of the first channel (330) is connected to the exhaust port of the compression device (200), and the inlet end of the second channel (340) is connected to the liquid phase outlet of the condensation device (100), so that the liquid phase material can exchange heat with the gas phase material in the first channel (330) after entering the second channel (340) to cool the gas phase material. An absorption tower (400) is provided, wherein the first inlet of the absorption tower (400) is connected to the outlet of the first channel (330), and the absorption tower (400) is configured to absorb the first component in the gaseous material so that the second component in the gaseous material is discharged from the exhaust port of the absorption tower (400).

2. The exhaust gas treatment system according to claim 1, characterized in that, It also includes a resolution tower (500), the inlet of which is connected to the outlet of the second channel (340).

3. The exhaust gas treatment system according to claim 2, characterized in that, After heat exchange, the gaseous material enters the absorption tower (400), where the first component is absorbed to form a mixed liquid phase. The outlet of the absorption tower (400) is used to discharge the mixed liquid phase. The inlet of the analytical tower (500) is connected to the outlet of the absorption tower (400); The analytical column (500) is configured to analyze the mixed liquid phase to separate the first component and the liquid phase material; The first outlet of the analytical column (500) is used to discharge the first component, and the second outlet of the analytical column (500) is used to discharge the liquid phase material.

4. The exhaust gas treatment system according to claim 3, characterized in that, It also includes a reflux pipe (600), through which the second outlet of the analytical tower (500) is connected to the absorption tower (400).

5. The exhaust gas treatment system according to any one of claims 1-4, characterized in that, The heat exchange device (300) is configured to allow the gaseous material in the first channel (330) to flow in the opposite direction to the liquid material in the second channel (340).

6. The exhaust gas treatment system according to claim 5, characterized in that, The heat exchange device (300) has a first side and a second side arranged opposite to each other. The inlet end of the first channel (330) and the outlet end of the second channel (340) are located on the first side of the heat exchange device (300), and the outlet end of the first channel (330) and the inlet end of the second channel (340) are located on the second side of the heat exchange device (300).

7. The exhaust gas treatment system according to any one of claims 1-4, characterized in that, The heat exchange device (300) includes a heat exchange shell (310) and heat exchange tubes (320). The heat exchange tube (320) is disposed inside the heat exchange shell (310), and the heat exchange tube (320) and the heat exchange shell (310) form the first channel (330) for conveying the gas phase material. The heat exchange tube (320) has a second channel (340) for conveying the liquid phase material.

8. The exhaust gas treatment system according to claim 7, characterized in that, The central axis of the heat exchange shell (310) coincides with the central axis of the heat exchange tube (320).

9. The exhaust gas treatment system according to any one of claims 1-4, characterized in that, The heat exchange device (300) has a plurality of heat exchange sections (350) along its length direction. Each heat exchange section (350) has a first flow channel section (351) and a second flow channel section (352). Along the length direction of the heat exchange device (300), the first flow channel sections (351) of each heat exchange section (350) are connected in sequence to form a first channel (330), and the second flow channel sections (352) of each heat exchange section (350) are connected in sequence to form a second channel (340).

10. The exhaust gas treatment system according to any one of claims 1-4, characterized in that, The exhaust gas is polycrystalline silicon exhaust gas, which includes hydrogen, hydrogen chloride and chlorosilane. The gaseous material includes the hydrogen and the hydrogen chloride, and the liquid material includes liquid chlorosilane.

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