Polycrystalline silicon production tail gas treatment device
By designing a polycrystalline silicon production exhaust gas treatment device and using the temperature difference of process materials to exchange heat, the problem of high energy consumption of polycrystalline silicon production exhaust gas treatment equipment is solved, and more efficient material heat recovery and utilization is achieved.
Patent Information
- Application Number
- CN202420438088.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-07
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-03-07
AI Technical Summary
During the polysilicon production process, the exhaust gas treatment equipment has not been fully optimized, resulting in high energy consumption and there is a potential for further recycling and utilization of material heat.
A polycrystalline silicon production exhaust gas treatment device is designed, which connects multiple heat exchangers and processing components through the exhaust pipe of the reducing furnace, including hydrogen heat exchangers, trichlorosilicon heat exchangers, circulating water heat exchangers, and self-generating heat exchangers. The ethylene glycol heat exchanger and chlorosilane separation tank make full use of the temperature difference of process materials for heat exchange, reducing the intervention of external refrigerant and heat media.
Through this device, the heat in the exhaust gas is effectively utilized, reducing energy consumption and production costs, while improving the efficiency of exhaust gas treatment, and achieving more efficient material heat recovery and utilization.
Smart Images
Figure CN222468561U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of polysilicon production, in particular to a polysilicon production tail gas treatment device. Background Art
[0002] The principle of the Siemens process for the production of polysilicon by the improved Siemens method is to reduce high-purity trichlorosilane with high-purity hydrogen on a high-purity silicon core at about 1100°C to generate polysilicon deposited on the silicon core. The improved Siemens process is based on the traditional Siemens process and has the advantages of energy saving, consumption reduction, recycling of a large number of by-products such as H2, HCI, SiCI4 and a large amount of by-product heat energy generated during the production process.
[0003] Polysilicon production uses Siemens' improved process. When the market competition for polysilicon products is fierce, optimizing and energy-saving the production process becomes particularly important. From a design perspective, optimizing and energy-saving the production process is itself standing at a higher starting line, which can allow enterprises to have lower production costs, create more benefits, and thus have stronger market competitiveness.
[0004] At present, the tail gas treatment process of most enterprises in polysilicon production is to first perform deep cooling and condensation, gas-liquid separation, then hydrogen compression, and then deep cooling and condensation again to achieve the purpose of separating hydrogen and chlorosilane in the tail gas. Although the energy has been fully recovered and utilized, there is still room for further optimization of the treatment process of the reduction furnace tail gas. Utility Model Content
[0005] In view of this, the utility model provides a polysilicon production tail gas treatment device, the main purpose of which is to optimize the treatment equipment of the reduction furnace tail gas, further recover and utilize the material heat, and reduce energy consumption.
[0006] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:
[0007] The utility model provides a polysilicon production tail gas treatment device, which comprises: a reduction furnace tail gas pipe and a non-condensable gas treatment part;
[0008] The reduction furnace tail gas pipe is sequentially connected to the tube side of the hydrogen heat exchanger, the trichlorosilane heat exchanger, the circulating water heat exchanger, the tube side of the first self-generated heat exchanger, the ethylene glycol heat exchanger and the upper end side of the chlorosilane separation tank, and the upper end of the chlorosilane separation tank is connected to one end of the shell side of the first self-generated heat exchanger;
[0009] The non-condensable gas processing section includes a compressor, a second autogenous heat exchanger, a hydrogen chloride absorption tower, a first cooler and a decomposition tower, the other end of the shell side of the first autogenous heat exchanger is connected to the inlet of the compressor, the outlet of the compressor, the tube side of the second autogenous heat exchanger and the lower end side of the hydrogen chloride absorption tower are connected in sequence, the upper end of the hydrogen chloride absorption tower, the shell side of the second autogenous heat exchanger and the activated carbon adsorption tower are connected in sequence, the bottom of the hydrogen chloride absorption tower is connected to the packing layer of the decomposition tower through a first pipeline, the bottom of the decomposition tower is connected to one end of the first cooler through a second pipeline, and the other end of the first cooler is connected to the upper end side of the hydrogen chloride absorption tower.
[0010] The purpose of the utility model and the solution to its technical problems can also be further achieved by adopting the following technical measures.
[0011] Optionally, a second cooler is further included, one end of the second cooler is connected to the outlet of the ethylene glycol heat exchanger, and the other end of the second cooler is connected to the side wall of the chlorosilane separation tank.
[0012] Optionally, the lower end of the chlorosilane separation tank is connected to a distillation separation system.
[0013] Optionally, the shell side of the second autogenous heat exchanger is connected to the lower end of the activated carbon adsorption tower, the upper end of the activated carbon adsorption tower is connected to one end of the shell side of the hydrogen heat exchanger, and the other end of the shell side of the hydrogen heat exchanger is connected to the reduction furnace chassis.
[0014] Optionally, a third autogenous heat exchanger is also included, the first pipeline runs through the tube side of the third autogenous heat exchanger, and the second pipeline runs through the shell side of the third autogenous heat exchanger.
[0015] Optionally, an exhaust pipe is also included, and the exhaust pipe is connected to the upper end of the analysis tower.
[0016] By means of the above technical solution, the utility model has at least the following advantages:
[0017] The reduction furnace tail gas flows through the hydrogen heat exchanger and trichlorosilane heat exchanger through the reduction furnace tail gas pipe, and first transfers its heat to hydrogen and trichlorosilane to preheat the hydrogen and trichlorosilane before entering the reduction furnace. At the same time, the temperature of the reduction furnace tail gas is also reduced. When the reduction furnace tail gas passes through the circulating water heat exchanger again, the temperature difference of the shell and tube of the circulating water heat exchanger is reduced, avoiding water vaporization at the junction of the shell and tube at the top of the circulating water heat exchanger, and avoiding dry burning of the circulating water heat exchanger.
[0018] Subsequently, the reduction furnace tail gas passes through the tube side of the first autogenous heat exchanger and the ethylene glycol heat exchanger in turn and reaches the chlorosilane separation tank. The chlorosilane in the tail gas is condensed, and the temperature of the non-condensable gas therein is also reduced. It enters the shell side of the first autogenous heat exchanger and uses the cold energy of the non-condensable gas to pre-cool the reduction furnace tail gas, thereby reducing the load of the ethylene glycol heat exchanger.
[0019] Subsequently, the non-condensable gas is compressed by the compressor. After being compressed, the non-condensable gas enters the hydrogen chloride absorption tower through the tube side of the second autogenous heat exchanger. The non-condensable gas rises in the hydrogen chloride absorption tower and is sprayed by the condensate output from the other end of the first cooler to the hydrogen chloride absorption tower. The hydrogen chloride in the non-condensable gas is absorbed and precipitated by the condensate. Most of the hydrogen in the non-condensable gas enters the shell side of the second autogenous heat exchanger to reduce the temperature of the non-condensable gas in the tube side of the second autogenous heat exchanger. In the activated carbon adsorption tower, after being filtered by activated carbon, the pure hydrogen can be recycled.
[0020] The solution in the kettle of the hydrogen chloride absorption tower reaches the packing layer of the analysis tower through the first pipeline. The solution stays in the packing layer for a period of time, and the hydrogen chloride in the solution is further condensed and liquefied. The solution in the kettle of the analysis tower enters the first cooler through the second pipeline, and then enters the hydrogen chloride absorption tower to be sprayed out as a spray liquid, thereby improving the absorption rate of hydrogen chloride in the non-condensable gas.
[0021] The device makes full use of the temperature difference of the process material itself for heat exchange, reduces the intervention of external refrigerant and heat medium, reduces energy consumption and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic structural diagram of a polysilicon production tail gas treatment device provided in an embodiment of the utility model.
[0023] The figure marks in the drawings of the specification include: hydrogen heat exchanger 1, trichlorosilane heat exchanger 2, circulating water heat exchanger 3, first self-generated heat exchanger 4, ethylene glycol heat exchanger 5, chlorosilane separation tank 6, compressor 7, second self-generated heat exchanger 8, hydrogen chloride absorption tower 9, first cooler 10, analysis tower 11, second cooler 12, first pipeline 13, second pipeline 14, activated carbon adsorption tower 15, third self-generated heat exchanger 16, exhaust pipe 17, tail gas pipe 18. DETAILED DESCRIPTION
[0024] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0025] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0026] like Figure 1 As shown, an embodiment of the utility model provides a polysilicon production tail gas treatment device, which includes: a reduction furnace tail gas pipe 18 and a non-condensable gas treatment part;
[0027] The reduction furnace tail gas pipe 18 is connected to the tube side of the hydrogen heat exchanger 1, the trichlorosilane heat exchanger 2, the circulating water heat exchanger 3, the tube side of the first self-generated heat exchanger 4, the ethylene glycol heat exchanger 5 and the upper end side of the chlorosilane separation tank 6 in sequence, and the upper end of the chlorosilane separation tank 6 is connected to one end of the shell side of the first self-generated heat exchanger 4;
[0028] The non-condensable gas processing section includes a compressor 7, a second autogenous heat exchanger 8, a hydrogen chloride absorption tower 9, a first cooler 10 and a desorption tower 11, the other end of the shell side of the first autogenous heat exchanger 4 is connected to the inlet of the compressor 7, the outlet of the compressor 7, the tube side of the second autogenous heat exchanger 8 and the lower end side of the hydrogen chloride absorption tower 9 are connected in sequence, the upper end of the hydrogen chloride absorption tower 9, the shell side of the second autogenous heat exchanger 8 and the activated carbon adsorption tower 15 are connected in sequence, the bottom of the hydrogen chloride absorption tower 9 is connected to the packing layer of the desorption tower 11 through a first pipeline 13, the bottom of the desorption tower 11 is connected to one end of the first cooler 10 through a second pipeline 14, and the other end of the first cooler 10 is connected to the upper end side of the hydrogen chloride absorption tower 9.
[0029] The working process of a polysilicon production tail gas treatment device is as follows:
[0030] The reduction furnace tail gas flows through the hydrogen heat exchanger 1 and the trichlorosilane heat exchanger 2 through the reduction furnace tail gas pipe 18, and first transfers its heat to the hydrogen and trichlorosilane to preheat the hydrogen and trichlorosilane before entering the reduction furnace. At the same time, the temperature of the reduction furnace tail gas is also reduced. When the reduction furnace tail gas passes through the circulating water heat exchanger 3 again, the temperature difference of the shell and tube of the circulating water heat exchanger 3 is reduced, so as to avoid the vaporization of water at the junction of the shell and tube at the top of the circulating water heat exchanger 3 and avoid the dry burning of the circulating water heat exchanger 3.
[0031] Subsequently, the reduction furnace tail gas passes through the tube side of the first autogenous heat exchanger 4 and the ethylene glycol heat exchanger 5 in turn, and reaches the chlorosilane separation tank 6, where the chlorosilane in the tail gas is condensed, and the temperature of the non-condensable gas therein is also reduced, and enters the shell side of the first autogenous heat exchanger 4, where the cooling capacity of the non-condensable gas is used to pre-cool the reduction furnace tail gas, thereby reducing the load of the ethylene glycol heat exchanger 5.
[0032] Subsequently, the non-condensable gas is compressed by the compressor 7. After being compressed, the non-condensable gas enters the hydrogen chloride absorption tower 9 through the tube side of the second autogenous heat exchanger 8. The non-condensable gas rises in the hydrogen chloride absorption tower 9 and is sprayed with the condensate output from the other end of the first cooler 10 to the hydrogen chloride absorption tower 9. The hydrogen chloride in the non-condensable gas is absorbed and precipitated by the condensate. Most of the hydrogen in the non-condensable gas enters the shell side of the second autogenous heat exchanger 8 to reduce the temperature of the non-condensable gas in the tube side of the second autogenous heat exchanger 8. In the activated carbon adsorption tower 15, after being filtered by activated carbon, the pure hydrogen can be recycled.
[0033] The solution in the kettle of the hydrogen chloride absorption tower 9 reaches the packing layer of the analysis tower 11 through the first pipeline 13. The solution stays in the packing layer for a period of time, and the hydrogen chloride in the solution is further condensed and liquefied. The solution in the kettle of the analysis tower 11 enters the first cooler 10 through the second pipeline 14, and then enters the hydrogen chloride absorption tower 9 to be sprayed out as a spray liquid, thereby improving the absorption rate of hydrogen chloride in the non-condensable gas.
[0034] In the technical solution of the utility model, the device fully utilizes the temperature difference of the process material itself for heat exchange, reduces the intervention of external refrigerant and heat medium, reduces energy consumption, and reduces costs.
[0035] Specifically, the refrigerant in the shell side of the ethylene glycol heat exchanger 5 is ethylene glycol.
[0036] Specifically, the refrigerant used in the shell side of the first cooler 10 and the second cooler 12 is 7° C. cooling water of the lithium bromide unit.
[0037] In a specific embodiment, a second cooler 12 is further included, one end of the second cooler 12 is connected to the outlet of the ethylene glycol heat exchanger 5 , and the other end of the second cooler 12 is connected to the side wall of the chlorosilane separation tank 6 .
[0038] In this embodiment, specifically, the outlet of the ethylene glycol heat exchanger 5 tube side, the second cooler 12 and the chlorosilane separation tank 6 are connected in sequence, which increases the flow rate of the tail gas condensate to the chlorosilane separation tank 6 and further improves the condensation and liquefaction rate of the tail gas.
[0039] In a specific embodiment, the lower end of the chlorosilane separation tank 6 is connected to a distillation separation system.
[0040] In this embodiment, specifically, the liquid chlorosilane condensate received by the chlorosilane separation tank 6 is transported to the distillation separation system to further separate trichlorosilane, dichlorosilane and silicon tetrachloride therein, and then they are recycled respectively.
[0041] In a specific embodiment, the shell side of the second autogenous heat exchanger 8 is connected to the lower end of the activated carbon adsorption tower 15, the upper end of the activated carbon adsorption tower 15 is connected to one end of the shell side of the hydrogen heat exchanger 1, and the other end of the shell side of the hydrogen heat exchanger 1 is connected to the reduction furnace chassis.
[0042] In this embodiment, specifically, after the hydrogen chloride in the non-condensable gas is absorbed, the hydrogen content therein is increased, and after the hydrogen passes through the activated carbon adsorption tower 15, the hydrogen content is further increased to meet the process requirements of the reduction deposition reaction hydrogen material. On this basis, in the hydrogen heat exchanger 1, the hydrogen is exchanged with the reduction furnace tail gas to preheat the hydrogen.
[0043] In a specific embodiment, a third autogenous heat exchanger 16 is further included, the first pipeline 13 passes through the tube side of the third autogenous heat exchanger 16 , and the second pipeline 14 passes through the shell side of the third autogenous heat exchanger 16 .
[0044] In the present embodiment, specifically, compared with the solution in the bottom of the hydrogen chloride absorption tower 9, the heat of the solution in the bottom of the analysis tower 11 is further dissipated, and the temperature of the solution in the bottom of the analysis tower 11 is relatively low. Therefore, in the third autogenous heat exchanger 16, the temperature of the liquid in the tube side is reduced, and then reaches the packing layer of the analysis tower 11 along the first pipeline 13, which is beneficial to the liquefaction and condensation of the hydrogen chloride therein, and avoids a large amount of hydrogen chloride discharged from the analysis tower 11.
[0045] In a specific embodiment, an exhaust pipe 17 is further included, and the exhaust pipe 17 is connected to the upper end of the analysis tower 11.
[0046] In this embodiment, specifically, in the analysis tower 11, the hydrogen chloride and a small amount of hydrogen that cannot be condensed are finally discharged to the cold hydrogenation process through the exhaust pipe 17, and the hydrogen therein is further utilized.
[0047] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.
Claims
1. A polysilicon production tail gas treatment device, characterized in that: include: A reduction furnace tail gas pipe, wherein the reduction furnace tail gas pipe is sequentially connected to the tube side of the hydrogen heat exchanger, the trichlorosilane heat exchanger, the circulating water heat exchanger, the tube side of the first autogenous heat exchanger, the ethylene glycol heat exchanger and the upper end side of the chlorosilane separation tank, and the upper end of the chlorosilane separation tank is connected to one end of the shell side of the first autogenous heat exchanger; A non-condensable gas treatment section, the non-condensable gas treatment section includes a compressor, a second autogenous heat exchanger, a hydrogen chloride absorption tower, a first cooler and a desorption tower, the other end of the shell side of the first autogenous heat exchanger is connected to the inlet of the compressor, the outlet of the compressor, the tube side of the second autogenous heat exchanger and the lower end side of the hydrogen chloride absorption tower are connected in sequence, the upper end of the hydrogen chloride absorption tower, the shell side of the second autogenous heat exchanger and the activated carbon adsorption tower are connected in sequence, the bottom of the hydrogen chloride absorption tower is connected to the packing layer of the desorption tower through a first pipeline, the bottom of the desorption tower is connected to one end of the first cooler through a second pipeline, and the other end of the first cooler is connected to the upper end side of the hydrogen chloride absorption tower.
2. The polysilicon production tail gas treatment device according to claim 1, characterized in that: It also includes a second cooler, one end of which is connected to the outlet of the ethylene glycol heat exchanger, and the other end of which is connected to the side wall of the chlorosilane separation tank.
3. The polysilicon production tail gas treatment device according to claim 1, characterized in that: The lower end of the chlorosilane separation tank is connected to a distillation separation system.
4. The polysilicon production tail gas treatment device according to claim 1, characterized in that: The shell side of the second autogenous heat exchanger is connected to the lower end of the activated carbon adsorption tower, the upper end of the activated carbon adsorption tower is connected to one end of the shell side of the hydrogen heat exchanger, and the other end of the shell side of the hydrogen heat exchanger is connected to the reduction furnace bottom plate.
5. The polysilicon production tail gas treatment device according to claim 1, characterized in that: It also includes a third autogenous heat exchanger, wherein the first pipeline runs through the tube side of the third autogenous heat exchanger, and the second pipeline runs through the shell side of the third autogenous heat exchanger.
6. The polysilicon production tail gas treatment device according to any one of claims 1 to 5, characterized in that: It also includes an exhaust pipe, which is connected to the upper end of the analysis tower.