Polycrystalline silicon tail gas recovery hydrogen adsorption tower regeneration device

Abstract

The utility model relates to a regeneration device of a hydrogen adsorption tower for recovering polycrystalline silicon tail gas. The device comprises an activated carbon adsorption tower, a hot water heat exchanger, a hydrogen preheater, a hydrogen heater and a hot water circulating pump. A finned jacketed pipe and a half-pipe jacket are arranged in the activated carbon adsorption tower, so that activated carbon in the tower is uniformly heated. Hot water for regeneration is pressurized through the hot water circulating pump, heated through the coiled tube type hot water heat exchanger and then introduced into the jacket, and efficient regeneration is achieved. The hydrogen preheater preheats back-blowing hydrogen by using reduction tail gas, the hydrogen heater heats the hydrogen to 180 DEG C, the hydrogen is back-blown to the tower bottom from the tower top, impurities on activated carbon are analyzed, and the regeneration effect is improved. The device further comprises a water supplementing tank, an expansion tank and a nitrogen compressor, hot water expansion and contraction are buffered through the expansion tank, the water supplementing tank supplements lost water, and the nitrogen compressor keeps system pressure stable. The device improves regeneration efficiency and hydrogen purity, prolongs the service life of activated carbon, and is energy-saving and efficient.

Description

Technical Field

[0001] The utility model relates to the technical field of impurity removal, specifically to the technical field of boron impurity removal in a salt lake lithium extraction process, and especially to a polysilicon tail gas recovery hydrogen adsorption tower regeneration device. Background Art

[0002] The adsorption tower is a critical piece of equipment in polysilicon tail gas recovery systems, used to absorb impurities such as HCl and chlorosilanes remaining in the hydrogen, thereby producing high-purity hydrogen. With the continuous expansion of polysilicon production capacity and the increasing amount of recovered tail gas, the matching adsorption towers are becoming increasingly larger, and the activated carbon capacity is also increasing, which places higher demands on the regeneration of activated carbon.

[0003] Existing activated carbon regeneration processes utilize traditional coil-tube adsorption towers and lack the use of hot hydrogen backflushing. During the regeneration process, the activated carbon is heated unevenly, even with significant dead zones. This results in low heating efficiency, prolonged tower regeneration times, and varying degrees of regeneration, creating quality risks. Incomplete impurity removal reduces the activated carbon's adsorption capacity. After passing impure hydrogen through the adsorption tower, the impurity content does not drop to the expected level, resulting in substandard hydrogen purity. Utility Model Content

[0004] The present invention aims to overcome the shortcomings of the prior art and provides a device for regenerating a polysilicon tail gas recovery adsorption tower, which is used to regenerate and activate the adsorbent with high efficiency and quality, thereby improving the recovery rate and purity of hydrogen and extending the service life of the activated carbon. The following technical solutions are adopted:

[0005] A polysilicon tail gas recovery hydrogen adsorption tower regeneration device comprises an activated carbon adsorption tower, a hot water heat exchanger, a hydrogen preheater, a hydrogen heater and a hot water circulation pump.

[0006] The activated carbon adsorption tower is used to adsorb hydrogen containing impurities and output pure hydrogen. It includes an adsorption device body, a finned jacketed tube, and a half-tube jacket. The finned jacketed tube consists of an inner tube, an outer tube, and fins. The finned jacketed tube is evenly inserted into the body of the activated carbon adsorption tower through the lower head. The half-tube jacket is evenly spirally wound counterclockwise and assembled on the outer wall of the cylinder of the activated carbon adsorption device. The activated carbon fills the entire internal space of the body. The finned tubes are arranged in an equidistant triangle in the adsorption column for uniform heating. The temperature field distribution of the entire cross section inside the equipment is basically the same. When hot water runs in the finned tube, the heat can be quickly transferred to the internal activated carbon through the surface of the heat exchange tube and the extended fins, and there is no dead zone in the heat exchange.

[0007] The regeneration water heat exchanger is used to heat regeneration hot water. 1.0 MPa steam is used to heat the regeneration hot water to 180°C before it is passed into the adsorption tower fin casing and half-tube jacket. The hydrogen preheater utilizes the temperature of the reduction tail gas to preheat the regeneration backflush hydrogen to above 100°C. Through heat exchange with the feed gas itself, the heat of the reduction tail gas is fully utilized.

[0008] The hydrogen heater uses 1.0 MPa steam to continue heating the regenerated back-flushed hydrogen after the reduced tail gas is reheated to 180°C. The hot hydrogen is back-flushed from the top of the adsorption tower to the bottom of the tower in the opposite direction of adsorption, completely desorbing the HCL and chlorosilane adsorbed on the activated carbon, thereby regenerating the activated carbon.

[0009] The regeneration water circulation pump is used for circulating the regeneration hot water flow. The hot water is pressurized by the hot water circulation pump, heated by the coiled-tube hot water heat exchanger, and then sent to the adsorption tower for heating and purging, and then returned to the circulation pump inlet.

[0010] Furthermore, it also includes a water supply tank, an expansion tank, and a nitrogen compressor. In order to avoid the decompression and gasification of hot water and replenish the loss, the expansion tank and the water supply tank are used. The expansion tank uses a nitrogen compressor to maintain stable pressure.

[0011] Furthermore, the regeneration water heat exchanger adopts a tube-wound heat exchanger whose tube bundle is composed of multiple layers of spirally wound heat exchange tubes. Each layer of heat exchange tubes is wound in opposite directions, and full countercurrent heat exchange is achieved. It has the unique advantages of compact structure, large unit heat exchange area, low heat loss, and high efficiency and energy saving.

[0012] The beneficial effects of the present invention include at least one of the following:

[0013] (1) The utility model adopts the structural design of finned jacketed tube and half-tube jacket, so that hot water flows evenly in the jacket, with high heating efficiency, ensuring uniform heating of activated carbon in the adsorption tower, thereby significantly improving regeneration efficiency;

[0014] (2) The utility model uses a regeneration process in which high-temperature hydrogen is backflushed from the top of the adsorption tower to the bottom, which can effectively resolve impurities such as HCl and chlorosilane adsorbed on the activated carbon and improve the purity of the hydrogen after regeneration.

[0015] (3) The utility model reduces the loss of activated carbon through uniform heating and efficient back-flushing regeneration process, prolongs the service life of activated carbon, and reduces replacement frequency and maintenance costs.

[0016] (4) The utility model utilizes the waste heat of the reduction tail gas to preheat the regeneration back-blowing hydrogen, making full use of energy, reducing the energy consumption of the system, and improving the overall energy utilization efficiency.

[0017] (5) The utility model prevents hot water from being decompressed and vaporized by the water supply tank and the expansion tank, and maintains the pressure stability of the water supply tank and the expansion tank by the nitrogen compressor, thereby ensuring that the device maintains safety and stability while operating efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram of an embodiment of the present utility model;

[0019] Figure 2 A schematic diagram of an activated carbon adsorption tower according to an embodiment of the present invention;

[0020] Figure 3 This is a cross-sectional schematic diagram of the finned jacketed tube of the utility model;

[0021] Figure 4 This is a schematic diagram of the arrangement of the finned jacketed tubes of the utility model inside the activated carbon adsorption tower.

[0022] In the figure: 1. Activated carbon adsorption tower; 2. Regeneration water heat exchanger; 3. Hydrogen preheater; 4. Hydrogen heater; 5. Regeneration water circulation pump; 6. Expansion tank; 7. Make-up water tank; 8. Nitrogen compressor; 101. Finned jacketed pipe; 102. Half-pipe jacket; 103. Inner pipe; 104. Outer pipe; 105. Fins. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1:

[0025] Reference Figures 1 to 3 This embodiment provides a polysilicon tail gas recovery hydrogen adsorption tower regeneration device, which consists of an activated carbon adsorption tower 1, a regeneration water heat exchanger 2, a hydrogen preheater 3, a hydrogen heater 4 and a regeneration water circulation pump 5.

[0026] The activated carbon adsorption tower 1 is used to adsorb impurity-containing hydrogen and output pure hydrogen. It includes the activated carbon adsorption tower 1 body, a finned jacketed tube 101, and a half-tube jacket 102. The finned jacketed tube 101 consists of three parts: an inner tube 103, an outer tube 104, and fins 105. A sandwich is formed between the inner tube 103 and the outer tube 104. The fins 105 are evenly distributed on the outside of the outer tube 103. The fins 105 are in a spiral or sheet-like structure. The finned jacketed tube 101 evenly passes through the lower head of the activated carbon adsorption tower 1 and is inserted into the body of the activated carbon adsorption tower 1. The half-tube jacket 102 is evenly spirally wound counterclockwise on the outer wall of the activated carbon adsorption tower 1. The activated carbon fills the entire internal space of the activated carbon adsorption tower 1. The finned jacketed tube 101 is arranged in an equidistant triangle inside the activated carbon adsorption tower 1 for uniform heating. The temperature field distribution of the entire cross-section inside the equipment is basically the same. When hot water runs in the finned tube, the heat can be quickly transferred to the internal activated carbon through the surface of the heat exchange tube and the extended fins, and there is no dead zone in the heat exchange.

[0027] Regeneration water heat exchanger 2 utilizes a coiled-tube hot water heat exchanger to heat the regeneration water. After being heated to 180°C with 1.0 MPa steam, the regeneration water is passed through finned jacketed tubes 101 and half-tube jackets 102. The coiled-tube heat exchanger's tube bundle consists of multiple layers of spirally wound heat exchange tubes, each layer wound in opposite directions for full countercurrent heat exchange. This unique advantage offers a compact structure, large unit heat exchange area, minimal heat loss, and high efficiency and energy conservation.

[0028] The heat source of the hydrogen preheater 3 is the polysilicon reduction tail gas. The hydrogen preheater 3 uses the temperature of the reduction tail gas to preheat the regeneration backwash hydrogen to above 100°C, and through the heat exchange of the material gas itself, the heat of the reduction tail gas can be fully utilized.

[0029] The inlet of the hydrogen heater 4 is connected to the outlet pipeline of the hydrogen preheater 3. The heat source of the hydrogen heater 4 is steam. The hydrogen heater 4 uses 1.0MPa steam to continue heating the regenerated backflushed hydrogen after the reduced tail gas is reheated to 180°C. The outlet of the hydrogen heater 4 is connected to the outlet pipeline at the top of the activated carbon adsorption tower 1. The hot hydrogen is backflushed from the top of the adsorption tower to the bottom of the tower in the opposite direction of adsorption, completely desorbing the HCL and chlorosilane adsorbed on the activated carbon, thereby regenerating the activated carbon.

[0030] The regeneration water circulation pump 5 is used for circulating the regeneration hot water flow. The outlet of the regeneration water circulation pump 5 is respectively connected to the lower inlet pipelines of the finned jacketed tube 101 and the half-pipe jacket 102, and the upper outlets of the finned jacketed tube 101 and the half-pipe jacket 102 are both connected to the inlet pipeline of the regeneration water circulation pump 5. The regeneration water is pressurized by the regeneration water circulation pump 5, heated by the regeneration water heat exchanger 2, and then sent to the finned jacketed tube 101 and the half-pipe jacket 102, and then returned to the inlet of the regeneration water circulation pump 5.

[0031] Preferably, the device proposed in this embodiment further includes an expansion tank 6, a water make-up tank 7, and a nitrogen compressor 8. The front end of the inlet of the regeneration water circulation pump 5 is provided with an expansion tank 6, a water make-up tank 7, and a nitrogen compressor 8. The expansion tank 6 is connected to the inlet pipeline of the regeneration water circulation pump 5, the water make-up tank 7 is connected to the expansion tank 6, and the nitrogen compressor 8 is connected to the expansion tank 6 and the water make-up tank 7. In order to avoid hot water decompression and gasification and replenishment loss, the expansion tank 6 and the water make-up tank 7 are used to achieve this. The expansion tank 6 and the water make-up tank 7 use the nitrogen compressor 8 to maintain pressure stability.

[0032] The working process of this embodiment is as follows:

[0033] The regeneration water is pressurized by the regeneration water circulation pump 5, heated by the regeneration water heat exchanger 2, and then sent to the finned jacketed pipe 101 and the half-pipe jacket 102 for heat exchange with the activated carbon. At the same time, the regeneration backwash hydrogen is heated by the hydrogen preheater 3 and the hydrogen heater 4. The hot hydrogen is backwashed from the top of the activated carbon adsorption tower 1 to the bottom of the tower in the opposite direction of adsorption. The HCL and chlorosilane impurities adsorbed on the activated carbon are blown to the regeneration treatment system for recovery under the backwash action of the hot hydrogen.

Claims

1. A polysilicon tail gas recovery hydrogen adsorption tower regeneration device, characterized in that: include: An activated carbon adsorption tower, wherein a plurality of finned jacketed tubes are provided inside the activated carbon adsorption tower, wherein the finned jacketed tubes pass through the lower head of the activated carbon adsorption tower and are inserted into the interior of the activated carbon adsorption tower, and a half-tube jacket is provided on the outer wall of the adsorption tower, wherein the half-tube jacket is evenly spirally wound and assembled on the outer wall of the cylinder of the activated carbon adsorption device; A hydrogen preheater, wherein the heat source of the hydrogen preheater is polysilicon reduction tail gas; A hydrogen heater, wherein the inlet of the hydrogen heater is connected to the outlet pipeline of the hydrogen preheater, the heat source of the hydrogen heater is steam, and the outlet of the hydrogen heater is connected to the outlet pipeline at the top of the activated carbon adsorption tower; A regeneration water circulation pump, wherein the outlet of the regeneration water circulation pump is connected to the lower inlet pipeline of the finned jacketed pipe and the half-pipe jacket respectively, and the upper outlets of the finned jacketed pipe and the half-pipe jacket are both connected to the inlet pipeline of the regeneration water circulation pump; The regeneration water heat exchanger is arranged on the pipeline between the outlet of the regeneration water circulation pump and the lower inlet of the fin-type jacketed pipe and the half-pipe jacket.

2. A polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 1, characterized in that: An expansion tank, a water replenishment tank, and a nitrogen compressor are provided at the front end of the inlet of the regenerated water circulation pump. The expansion tank is connected to the inlet pipeline of the regenerated water circulation pump, the water replenishment tank is connected to the expansion tank, and the nitrogen compressor is connected to the expansion tank and the water replenishment tank.

3. A polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 1 or 2, characterized in that: The finned jacketed tube consists of three parts: an inner tube, an outer tube and fins. A sandwich is formed between the inner tube and the outer tube. The fins are evenly distributed on the outside of the outer tube. The fins are in a spiral or sheet-like structure.

4. A polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 3, characterized in that: The finned jacketed tubes are arranged in an equidistant triangle arrangement in the activated carbon adsorption tower.

5. The polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 1, characterized in that: The regeneration water heat exchanger adopts a coiled tube hot water heat exchanger.

6. A polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 5, characterized in that: The regeneration water heat exchanger utilizes 1.0 MPa steam to heat the regeneration water to 180°C.

7. The polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 1, characterized in that: The hydrogen preheater utilizes the waste heat of the reduction tail gas to preheat the regenerated back-blowing hydrogen to above 100°C.

8. The polysilicon tail gas recovery hydrogen adsorption tower regeneration device according to claim 1, characterized in that: The hydrogen heater heats the preheated hydrogen to 180° C. using 1.0 MPa steam.

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