A reduction tail gas heat utilization system
By designing a system for utilizing the heat from the exhaust gas, the problem of high energy consumption in polysilicon production was solved, the full utilization of the heat from the exhaust gas was achieved, and the risks of power consumption and system malfunctions were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- INNER MONGOLIA TONGWEI HIGH PURITY CRYSTAL SILICON CO LTD
- Filing Date
- 2025-05-03
- Publication Date
- 2026-05-29
AI Technical Summary
Polysilicon production consumes a lot of energy, especially electricity costs in the reduction process, and existing technologies have failed to effectively utilize the heat from the reduction exhaust gas.
Design a reduction exhaust gas heat utilization system, including a reduction furnace, filter, recovery condensation system and adsorption column. Through jacket, heating unit and pipeline design, the exhaust gas heat is fully utilized to reduce the steam heating requirement for trichlorosilane.
This achieves full utilization of the heat from the reduced exhaust gas, reduces energy and electricity consumption, and avoids system malfunctions and quality accidents.
Smart Images
Figure CN224293225U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of polycrystalline silicon technology, specifically to a system for utilizing the heat of reduction exhaust gas. Background Technology
[0002] Polycrystalline silicon is a form of elemental silicon, primarily produced by chlorinating dry hydrogen chloride gas and dry silicon powder under specific conditions, followed by condensation, distillation, and reduction. Depending on the application, polycrystalline silicon can be broadly categorized into electronic-grade polycrystalline silicon, solar-grade polycrystalline silicon, and metallurgical-grade polycrystalline silicon. Current major production processes for polycrystalline silicon include the modified Siemens process, fluidized bed process, gas-liquid deposition process, and silane process. Among these, the modified Siemens process, with its advantages of low investment risk, low production cost, and ease of expansion, has become the mainstream production process in the industry.
[0003] Currently, the production of polysilicon is energy-intensive, requiring a large amount of electricity, especially in processes such as reduction, where electricity costs account for a significant portion. Utility Model Content
[0004] The purpose of this invention is to develop a reduction exhaust gas heat utilization system that utilizes the heat of the reduction exhaust gas to reduce energy consumption.
[0005] This utility model is achieved through the following technical solution:
[0006] A system for utilizing the heat of reduced exhaust gas, comprising:
[0007] Reduction furnace;
[0008] The filter is connected to the reduction furnace;
[0009] The trichlorosilane pipeline is connected to the reduction furnace;
[0010] The heating unit is located on the trichlorosilane pipeline;
[0011] The filter is connected to a gas supply pipe on the side away from the reduction furnace, and the gas supply pipe is connected to the heating unit. The heating unit is also connected to a return gas pipe.
[0012] Optionally, the heating unit includes a preheater, a vaporizer, and a superheater arranged sequentially on a trichlorosilane pipeline.
[0013] Optionally, a fifth valve is provided on the pipeline between the gas supply pipe and the preheater, vaporizer and superheater.
[0014] Optionally, a jacket is also connected to the pipeline between the reduction furnace and the filter.
[0015] Optionally, a first valve is provided on the pipeline between the reduction furnace and the filter, and the jacket is connected to the pipelines on both sides of the first valve.
[0016] Optionally, the jacket is provided with an air inlet pipe and an air outlet pipe, and the air inlet pipe and the air outlet pipe are respectively provided with a second valve and a third valve, and the air inlet pipe and the air outlet pipe are respectively connected to the pipelines on both sides of the first valve.
[0017] Optionally, the system also includes a recovery condensation system and an adsorption column, wherein the reduction furnace, filter, recovery condensation system and adsorption column are sequentially connected by pipelines.
[0018] Optionally, the adsorption column is connected to the reduction furnace pipeline.
[0019] Optionally, a fourth valve is provided on the pipeline between the filter and the recovery condensation system, the gas supply pipe is connected to the pipeline between the fourth valve and the filter, and the gas return pipe is connected to the pipeline between the fourth valve and the recovery condensation system.
[0020] Optionally, a spare pipeline is also connected between the filter and the recovery condensation system. A sixth valve is provided on the spare pipeline, and the spare pipeline is connected to the pipelines on both sides of the fourth valve.
[0021] The beneficial effects of this utility model are:
[0022] This invention can fully utilize the heat of the reduction exhaust gas, reduce energy consumption and electrical energy consumption, and eliminate the need to use steam to heat trichlorosilane, thus avoiding internal leaks that could cause system malfunctions and quality accidents. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a structural diagram of the present utility model.
[0025] Reference numerals: 1. First valve; 2. Second valve; 3. Third valve; 4. Fourth valve; 5. Fifth valve; 6. Sixth valve. Detailed Implementation
[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0027] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0028] In this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0029] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0030] like Figure 1 As shown, this utility model discloses a reduction tail gas heat utilization system, including a reduction furnace, a filter, a recovery condensation system and an adsorption column connected in sequence by pipelines. The reduction tail gas output from the reduction furnace can pass through the filter, the recovery condensation system and the adsorption column in sequence. The adsorption column is also connected to the reduction furnace. After a series of treatments, the hydrogen gas output from the adsorption column is sent back to the reduction furnace.
[0031] A first valve 1 is installed on the pipeline between the reduction furnace and the filter. A jacket is also connected between the reduction furnace and the filter. An inlet pipe and an outlet pipe are installed on the jacket. The inlet pipe and the outlet pipe are respectively connected to the pipelines on both sides of the first valve 1. A second valve 2 and a third valve 3 are also installed on the inlet pipe and the outlet pipe, respectively.
[0032] The reduction tail gas output from the reduction furnace can be first passed into the jacket to heat the water passing through the jacket, thereby achieving heat exchange and cooling of the reduction tail gas and heat exchange and heating of the water, thus realizing heat utilization.
[0033] The reduction furnace is also connected to a trichlorosilane pipeline, through which refined trichlorosilane is fed into the reduction furnace. The trichlorosilane pipeline is equipped with a heating unit for heating the trichlorosilane. The heating unit includes a preheater, a vaporizer, and a superheater sequentially arranged on the trichlorosilane pipeline. The refined trichlorosilane is fed into the reduction furnace after passing through these three stages in sequence.
[0034] A fourth valve 4 is installed on the pipeline between the filter and the recovery condensation system. A gas supply pipe is connected to the pipeline near the filter side of the fourth valve 4, and this gas supply pipe is connected to the pipelines of the preheater, vaporizer, and superheater. A fifth valve 5 is installed on each of these pipelines. A return gas pipe is connected to the pipeline near the recovery condensation system side of the fourth valve 4, and this return gas pipe is connected to the pipelines of the preheater, vaporizer, and superheater.
[0035] The reduction exhaust gas output from the filter can enter the gas supply pipe, and then enter the superheater, vaporizer and preheater to exchange heat with refined trichlorosilane. After that, it is sent back through the return gas pipe and enters the recovery condensation system.
[0036] There is also a spare pipeline connecting the filter and the recovery condensation system. The spare pipeline is equipped with a sixth valve 6, and the spare pipeline is connected to the pipelines on both sides of the fourth valve 4.
[0037] When the high-temperature reduction tail gas output from the reduction furnace is sent to the filter, the first valve 1 can be opened and the second valve 2 and the fourth valve 4 can be closed to allow all the reduction tail gas to enter the filter. Alternatively, the first valve 1, the second valve 2, and the third valve 3 can be opened to allow part of the reduction tail gas to pass through the jacket for heat exchange before entering the filter. Or, the first valve 1 can be closed and the second valve 2 and the third valve 3 can be opened to allow all the reduction tail gas to enter the jacket for heat exchange before entering the filter.
[0038] After the silica powder in the reduction tail gas is filtered out, the tail gas enters the superheater, vaporizer, and preheater through the gas supply pipe. After exchanging heat with the trichlorosilane in these components, it is returned through the return pipe and enters the recovery condensation system. The refined trichlorosilane is then heated sequentially through the preheater, vaporizer, and superheater before being sent to the reduction furnace. The recovery condensation system uses circulating water and media at 7°C, -10°C, -40°C, and -70°C to cool the reduction tail gas. The chlorosilanes in the tail gas are condensed and recovered. The tail gas then enters an adsorption column for impurity adsorption treatment. The adsorption material in the column is activated carbon. The remaining hydrogen is then returned to the reduction furnace for reuse.
[0039] The pressure difference across the fourth valve 4 is controlled by adjusting its opening, ensuring smooth flow of the reduction tail gas. When the volume of reduction tail gas is large, the sixth valve 6 can be opened to allow some of the reduction tail gas to be sent to the recovery and condensation system through the reserve pipeline.
[0040] This invention can fully utilize the heat of the reduction exhaust gas, reduce energy consumption and electrical energy consumption, and eliminate the need to use steam to heat trichlorosilane, thus avoiding internal leaks that could cause system malfunctions and quality accidents.
[0041] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.
Claims
1. A system for utilizing the heat of reduced exhaust gas, characterized in that, include: Reduction furnace; The filter is connected to the reduction furnace; The trichlorosilane pipeline is connected to the reduction furnace; The heating unit is located on the trichlorosilane pipeline; The filter is connected to a gas supply pipe on the side away from the reduction furnace, and the gas supply pipe is connected to the heating unit. The heating unit is also connected to a return gas pipe.
2. The reduction exhaust gas heat utilization system according to claim 1, characterized in that, The heating unit includes a preheater, a vaporizer, and a superheater arranged sequentially on a trichlorosilane pipeline.
3. The reduction exhaust gas heat utilization system according to claim 2, characterized in that, A fifth valve is installed on the pipeline between the gas supply pipe and the preheater, vaporizer and superheater.
4. The reduction exhaust gas heat utilization system according to claim 1, characterized in that, A jacket is also connected to the pipeline between the reduction furnace and the filter.
5. The reduction exhaust gas heat utilization system according to claim 4, characterized in that, A first valve is provided on the pipeline between the reduction furnace and the filter, and the jacket is connected to the pipelines on both sides of the first valve.
6. The reduction exhaust gas heat utilization system according to claim 5, characterized in that, The jacket is provided with an air inlet pipe and an air outlet pipe, and the air inlet pipe and the air outlet pipe are respectively provided with a second valve and a third valve. The air inlet pipe and the air outlet pipe are respectively connected to the pipelines on both sides of the first valve.
7. The reduction tail gas heat utilization system according to any one of claims 1 to 6, characterized in that, The system also includes a recovery condensation system and an adsorption column, with the reduction furnace, filter, recovery condensation system and adsorption column connected in sequence via pipelines.
8. The reduction exhaust gas heat utilization system according to claim 7, characterized in that, The adsorption column is connected to the reduction furnace pipeline.
9. The reduction exhaust gas heat utilization system according to claim 7, characterized in that, A fourth valve is provided on the pipeline between the filter and the recovery condensation system. The gas supply pipe is connected to the pipeline between the fourth valve and the filter, and the gas return pipe is connected to the pipeline between the fourth valve and the recovery condensation system.
10. The reduction exhaust gas heat utilization system according to claim 9, characterized in that, The filter is also connected to the recovery condensation system by a spare pipeline, which is equipped with a sixth valve and is connected to the pipelines on both sides of the fourth valve.