Silane gas waste heat boiler

Abstract

The utility model provides a silane gas waste heat boiler which aims at solving the technical problem that silane gas waste heat utilization is not efficient in the existing polycrystalline silicon production field. The interior of the heat exchange furnace is divided into a heating section and an evaporation section through a first partition plate from top to bottom, and shell passes of the heating section and the evaporation section are not communicated. And the tube pass of the heat exchanger is a silane gas channel. And the silane gas flows out from the heating section through the evaporation section. And the heating section shell pass is used for circulating and heating the hydrogenated gas. And the evaporation section shell pass is used for circulating and heating boiler water. And the gas-liquid separation tank is provided with a boiler water inlet pipeline and a steam outlet pipeline. And the steam outlet pipeline is connected with the chlorosilane preheater. The gas-liquid separation tank is connected with the evaporation section shell side in a matched mode through the connecting pipe set and used for supplying water to the evaporation section shell side boiler and achieving gas-liquid separation in the gas-liquid separation tank. The heating section and the evaporation section are coupled in the heat exchange furnace, so that silane gas introduced into the furnace is subjected to heat exchange with hydrogenated gas and boiler water in sequence, and the waste heat of the silane gas is fully utilized.

Description

Technical Field

[0001] The utility model belongs to the technical field of polysilicon production, and in particular relates to a silane gas waste heat boiler. Background Art

[0002] In the current mainstream polysilicon production process, the hydrogenation furnace is the core equipment in polysilicon production. Its principle is to continuously introduce high-purity hydrogen and chlorosilane into the hydrogenation furnace while high pressure breaks through the high-purity silicon core, so that the 1100°C hydrogen can reduce chlorosilane to generate elemental silicon and deposit it on the surface of the silicon core.

[0003] Since chlorosilane is in liquid state under normal conditions, it is necessary to preheat chlorosilane to the reaction temperature in a silane preheater before the hydrogenation reaction. Traditional silane preheaters usually use water vapor as a heat exchange medium to ensure the preheating effect. The water vapor is usually the product of directly heating water using electricity or fire. However, this method has high energy consumption requirements and is not efficient in energy utilization.

[0004] Furthermore, a large amount of high-temperature silane gas will be generated after the hydrogenation reaction is completed. If it is directly discharged, it will cause heat energy waste and environmental pollution. At present, there is a hydrolysis alkali absorption method that uses silane waste gas to undergo subsequent treatment processes such as washing with 10% NaOH solution, and then discharge the remaining gas through the chimney. However, this method not only wastes a large amount of chlorosilane waste heat, but also requires a large amount of washing cold liquid. However, if the silane gas is cooled by multiple condensing heat exchangers before hydrolysis alkali absorption, and then washed by a washing tower, this will undoubtedly increase the number of equipment and increase production costs. Utility Model Content

[0005] The purpose of the utility model is to provide a silane gas waste heat boiler to solve the problems raised in the above background technology.

[0006] A silane gas waste heat boiler, comprising:

[0007] A heat exchange furnace, wherein the first partition plate divides the furnace shell into a temperature rise section and an evaporation section which are not interconnected from top to bottom; the heat exchange furnace tube side is a silane gas channel; the silane gas flows out from the temperature rise section through the evaporation section;

[0008] The shell side of the temperature rising section is used for the circulation of hydrogen gas; the shell side outlet of the temperature rising section is connected to an electric heater;

[0009] The shell side of the evaporation section is used for circulating and heating boiler water;

[0010] The gas-liquid separation tank is provided with a boiler water inlet pipe and a steam outlet pipe; the steam outlet pipe is connected to the chlorosilane preheater; the gas-liquid separation tank is matched and connected to the evaporation section shell side through a connecting pipe group, which is used for supplying boiler water to the evaporation section shell side and realizing gas-liquid separation in the gas-liquid separation tank.

[0011] Furthermore, the temperature rising section is divided into a preheating section and a heating section by a second partition; the preheating section is arranged below the heating section;

[0012] The preheating section has a tube-side inlet connected to a silane gas inlet pipeline for introducing silane gas from the hydrogenation furnace outlet; the shell-side inlet of the preheating section is connected to a hydrogen gas inlet pipeline;

[0013] The shell side of the heating section is connected to the shell side of the preheating section through a pipeline provided with a first regulating valve; the shell side outlet of the heating section is connected to the electric heater.

[0014] Furthermore, the electric heater is connected to the hydrogenation furnace.

[0015] Furthermore, the outlet of the evaporation section pipe is connected to the washing system through a spray pipe; a second regulating valve is provided at the spray pipe.

[0016] Furthermore, the steam outlet pipeline is provided with a pressure regulating valve; the boiler water inlet pipeline is provided near the bottom end of the gas-liquid separation tank, and the boiler water inlet pipeline is provided with a water inlet regulating valve;

[0017] The connecting pipe group includes an ascending pipe and a descending pipe;

[0018] One end of the riser is connected to the shell side of the evaporation section; the other end of the riser is arranged in the gas-liquid separation tank at a height exceeding the height of the boiler water inlet pipe arranged in the gas-liquid separation tank;

[0019] One end of the downcomer is connected to the shell side of the evaporation section, and the other end is connected to the bottom end of the gas-liquid separation tank.

[0020] Furthermore, the boiler water inlet pipe is arranged near the bottom end of the gas-liquid separation tank; the other end of the riser is arranged in the gas-liquid separation tank at a height exceeding half the height of the gas-liquid separation tank.

[0021] Furthermore, a drum remote liquid level gauge is provided on the side wall of the gas-liquid separation tank; and a steam outlet remote pressure gauge is provided on the top wall of the side wall of the gas-liquid separation tank.

[0022] Furthermore, the steam outlet pipeline is connected to four silicon preheaters and four silicon vaporizers, and is used to heat and raise the temperature of silicon materials required before the hydrogenation furnace reacts.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] (1) Coupling the heating section and the evaporation section in one heat exchange furnace not only reduces the number of equipment but also helps save site area;

[0025] (2) The outlet silane gas after the hydrogenation furnace reaction is heat exchanged with the hydrogen gas that passes through the preheating section shell and the heating section shell, and then heat exchanged with the boiler water in the evaporation section shell, so that the waste heat of the silane gas is fully utilized. At the same time, the hydrogen gas after heat exchange is heated by the electric heater and then passed to the hydrogenation furnace, and the silane gas is washed in the washing tower after secondary heat exchange, which is conducive to reducing the process energy consumption. Furthermore, the by-product steam of the boiler water after heat exchange is used for preheating the chlorosilane required before the hydrogenation furnace reaction, which greatly improves the energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a schematic diagram of the planar structure of a silane gas waste heat boiler according to an embodiment of the present application.

[0028] Reference numerals:

[0029] 10. Preheating section; 11. Heating section; 12. Second baffle; 13. Hydrogen gas inlet pipeline; 14. First baffle; 16. Hydrogen gas outlet pipeline;

[0030] 2. Gas-liquid separation tank; 21. Boiler water inlet pipe; 210. Water inlet regulating valve; 22. Steam outlet pipe; 220. Pressure regulating valve; 23. Steam drum remote level gauge; 24. Steam outlet remote pressure gauge; 25. Rising pipe; 26. Downcomer;

[0031] 3. Evaporation section;

[0032] 40. Silane gas inlet pipe; 41. Spray pipe;

[0033] 50. Pipeline; 51. First regulating valve. DETAILED DESCRIPTION

[0034] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0035] In the description of the present utility model, it should be understood that the terms "height", "up", "down", "top", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships conventionally placed when the product of the present utility model is used, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present utility model.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numerals in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments discussed.

[0040] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0041] The utility model embodiment provides a silane gas waste heat boiler, please refer to Figure 1 The silane gas waste heat boiler comprises a heat exchange furnace and a gas-liquid separation tank 2 .

[0042] The heat exchange furnace is divided from top to bottom into a temperature rising section and an evaporation section 3 which are not interconnected in the furnace shell side by the first partition 14. The heat exchange furnace tube side is a silane gas channel. The silane gas flows out from the temperature rising section through the evaporation section 3. The shell side of the temperature rising section is used for the circulation of hydrogen gas. The outlet of the shell side of the temperature rising section is connected to an electric heater. The shell side of the evaporation section 3 is used for the circulation and heating of boiler water.

[0043] The gas-liquid separation tank 2 is provided with a boiler water inlet pipe 21 and a steam outlet pipe 22. The steam outlet pipe 22 is connected to the silicon material preheater. The gas-liquid separation tank 2 is matched and connected to the shell side of the evaporation section 3 through a connecting pipe group, which is used to supply boiler water to the shell side of the evaporation section 3 and realize gas-liquid separation in the gas-liquid separation tank 2.

[0044] The silane gas waste heat boiler couples the heating section and the evaporation section 3 in a heat exchange furnace, so that the silane gas introduced into the tube side of the furnace exchanges heat with the hydrogen gas in the shell side of the heating section and the boiler water in the shell side of the evaporation section in turn, thereby making full use of the waste heat of the silane gas.

[0045] Specifically,

[0046] The heat exchange furnace is divided into an evaporation section 3 and a heating section by a first partition 14. The evaporation section 3 is arranged below the heating section. The tube side of the heat exchange furnace is a silane gas channel. The silane gas flows out from the heating section through the evaporation section 3. The shell side of the heating section is used as a hydrogen gas channel. The heating section is provided with a second partition 12, which divides the heating section from bottom to top into a preheating section 10 and a heating section 11.

[0047] The preheating section 10 has a tube-side inlet connected to a silane gas inlet pipeline 40 for introducing silane gas from the hydrogenation furnace outlet. The shell-side inlet of the preheating section 10 is connected to a hydrogen gas inlet pipeline 13. The hydrogen gas inlet pipeline 13 can introduce hydrogen gas at 210°C-230°C.

[0048] The shell side of the heating section 11 is connected to the shell side of the preheating section 10 through a pipeline 50 to serve as a hydrogen gas flow channel. The pipeline 50 is provided with a first regulating valve 51, which can adjust the flow rate of hydrogen gas from the preheating section 10 to the heating section 11 to meet the process requirements. The shell side outlet of the heating section 11 is connected to a hydrogen gas outlet pipeline 16. The hydrogen gas outlet pipeline 16 is connected to an electric heater. The electric heater is arranged between the shell side outlet of the heating section 11 and the hydrogenation furnace.

[0049] Therefore, the flow route of hydrogen gas in the heat exchange furnace is: hydrogen gas enters the preheating section 10 through the hydrogen gas inlet pipe 13, flows through the pipe 50 controlled by the first regulating valve 51, flows to the heating section 11, and then flows out from the shell outlet of the heating section 11 to be heated by the electric heater, and finally flows to the hydrogenation furnace for reaction.

[0050] The shell side of the evaporation section 3 is not connected to the shell side of the temperature rising section. The outlet of the tube side of the evaporation section 3 is connected to the washing system through a spray pipe 41 to spray the silane gas at the outlet of the tube side of the evaporation section 3, thereby facilitating the recovery of the silane gas. A second regulating valve is provided at the spray pipe 41. The washing system adopts a washing tower.

[0051] Therefore, the flow route of silane gas in the heat exchange furnace is: silane gas enters the preheating section 10 through the silane gas inlet pipe 40, then flows through the heating section 11 and the evaporation section 3 in sequence, and then flows out from the outlet of the evaporation section 3 to the washing tower.

[0052] The gas-liquid separation tank 2 is provided with a boiler water inlet pipe 21 near the bottom. The boiler water inlet pipe 21 is provided with a water inlet regulating valve 210 to regulate the flow of boiler water entering the gas-liquid separation tank 2. A steam outlet pipe 22 is provided at the top of the gas-liquid separation tank 2, and a pressure regulating valve 220 is provided at the steam outlet pipe 22, so that the steam can be discharged according to the process requirements. The gas-liquid separation tank 2 is matched and connected with the shell side of the evaporation section 3 through a connecting pipe group. The connecting pipe group includes a downcomer 26 and an upcomer 25. The downcomer 26 is connected to the shell side of the evaporation section 3 at one end, and connected to the bottom of the gas-liquid separation tank 2 at the other end. The upcomer 25 is connected to the shell side of the evaporation section 3 at one end, and matched and arranged in the gas-liquid separation tank 2 at the other end. That is, the setting height of one end of the upcomer 25 in the gas-liquid separation tank 2 exceeds half the height of the gas-liquid separation tank 2. The above structural design is conducive to the gas-liquid separation of the gas-liquid separation tank 2.

[0053] In order to facilitate the control of the liquid level of the gas-liquid separation tank 2, a drum remote level gauge 23 is provided on the side wall of the gas-liquid separation tank 2. In order to facilitate the control of the gas pressure of the steam outlet pipe 22, a steam outlet remote pressure gauge 24 is provided on the top wall of the gas-liquid separation tank 2. In addition, the steam outlet pipe 22 can be connected to the four silicon preheaters and the four silicon vaporizers to utilize the waste heat of the steam to heat the silicon material before entering the hydrogenation furnace for reaction.

[0054] When boiler water enters the gas-liquid separator 2 from the boiler water inlet pipe 21, it flows to the shell side of the evaporation section 3 through the downcomer 26, and the silane gas in the tube side of the evaporation section 3 can be condensed. The steam drum generated after the boiler water heat exchange enters the gas-liquid separator 3 from the riser 25, and flows from the steam outlet pipe 22 to the four silicon preheaters and four silicon vaporizers. At the same time, with the cooperation of the water inlet regulating valve 210, the pressure regulating valve 220, the steam drum remote level meter 23, and the steam outlet remote pressure gauge 24, it is convenient to maintain and control the gas-liquid separation state of the gas-liquid separator 2.

[0055] Based on the above embodiments, the working method of this application is as follows:

[0056] While the silane gas at the outlet of the hydrogenation furnace is passed into the heat exchange furnace tube, the hydrogen gas at 210°C-230°C passes through the preheating section 10 shell side and the heating section 11 shell side in sequence, and exchanges heat with the silane gas. During the heat exchange process, the waste heat of the silane gas can heat the hydrogen gas to 460°C-490°C in the shell side, so as to realize the one-time utilization of the waste heat of the silane gas. In addition, the hydrogen gas before passing into the hydrogenation furnace first uses the waste heat of the silane gas to preheat it to a higher temperature, and then is heated by the electric heater, which is conducive to saving energy consumption.

[0057] Since the silane gas after heat exchange with hydrogen gas still has a high temperature after entering the evaporation section 3 along the heat exchange furnace tube, the boiler water in the gas-liquid separation tank 2 flows to the shell side of the evaporation section 3 through the downcomer 26 to exchange heat with the silane gas. The steam separated from the steam drum generated by the steam drum after flowing through the gas-liquid separation tank 2 through the riser 25 is used for the preheating of silicon materials required before the hydrogenation furnace reaction, realizing the secondary utilization of the waste heat of the silane gas and greatly improving the utilization rate of energy. Finally, the silane gas that has undergone secondary heat exchange is passed to the scrubber for spraying, which greatly reduces the required cooling capacity of the scrubbing liquid.

[0058] Based on the above embodiments, the advantages of this application are:

[0059] (1) Coupling the heating section and the evaporation section 3 in one heat exchange furnace not only reduces the number of equipment but also helps save site area;

[0060] (2) The outlet silane gas after the hydrogenation furnace reaction is heat exchanged with the hydrogen gas in the preheating section 10 shell side and the heating section 11 shell side in turn, and then heat exchanged with the boiler water in the evaporation section 3 shell side, so that the waste heat of the silane gas is fully utilized. At the same time, the hydrogen gas after heat exchange and heating enters the electric heater for heating before passing to the hydrogenation furnace, and the silane gas flows to the washing tower for washing after secondary heat exchange, which is conducive to reducing the process energy consumption. Furthermore, the by-product steam of the boiler water after heat exchange and heating can be used for preheating the chlorosilane required before the hydrogenation furnace reaction, which greatly improves the energy utilization rate.

Claims

1. A silane gas waste heat boiler, characterized in that: The silane gas waste heat boiler comprises: A heat exchange furnace, wherein the first partition plate divides the furnace shell into a temperature rise section and an evaporation section which are not interconnected from top to bottom; the heat exchange furnace tube side is a silane gas channel; the silane gas flows out from the temperature rise section through the evaporation section; The shell side of the temperature rising section is used for the circulation of hydrogen gas; the shell side outlet of the temperature rising section is connected to an electric heater; The shell side of the evaporation section is used for circulating and heating boiler water; The gas-liquid separation tank is provided with a boiler water inlet pipe and a steam outlet pipe; the steam outlet pipe is connected to the silicon material preheater; the gas-liquid separation tank is matched and connected to the evaporation section shell side through a connecting pipe group, which is used for supplying boiler water to the evaporation section shell side and realizing gas-liquid separation in the gas-liquid separation tank.

2. The silane gas waste heat boiler according to claim 1, characterized in that: The temperature rising section is divided into a preheating section and a heating section by a second partition; the preheating section is arranged below the heating section; The preheating section has a tube-side inlet connected to a silane gas inlet pipeline for introducing silane gas from the hydrogenation furnace outlet; the preheating section shell-side inlet is connected to a hydrogen gas inlet pipeline; The shell side of the heating section is connected to the shell side of the preheating section through a pipeline provided with a first regulating valve; the shell side outlet of the heating section is connected to the electric heater.

3. The silane gas waste heat boiler according to claim 2, characterized in that: The electric heater is connected to the hydrogenation furnace.

4. The silane gas waste heat boiler according to claim 1, characterized in that: The outlet of the evaporation section pipe is connected to the washing system through a spray pipe; a second regulating valve is provided at the spray pipe.

5. The silane gas waste heat boiler according to any one of claims 1 to 4, characterized in that: The steam outlet pipe is provided with a pressure regulating valve; the boiler water inlet pipe is provided near the bottom end of the gas-liquid separation tank, and the boiler water inlet pipe is provided with a water inlet regulating valve; The connecting pipe group includes an ascending pipe and a descending pipe; One end of the riser is connected to the shell side of the evaporation section; the other end of the riser is arranged in the gas-liquid separation tank at a height exceeding the height of the boiler water inlet pipe arranged in the gas-liquid separation tank; One end of the downcomer is connected to the shell side of the evaporation section, and the other end is connected to the bottom end of the gas-liquid separation tank.

6. The silane gas waste heat boiler according to claim 5, characterized in that: The boiler water inlet pipe is arranged near the bottom end of the gas-liquid separation tank; the other end of the riser is arranged in the gas-liquid separation tank at a height exceeding half the height of the gas-liquid separation tank.

7. The silane gas waste heat boiler according to claim 5, characterized in that: The side wall of the gas-liquid separation tank is provided with a drum remote liquid level gauge; the top wall of the side wall of the gas-liquid separation tank is provided with a steam outlet remote pressure gauge.

8. The silane gas waste heat boiler according to claim 7, characterized in that: The steam outlet pipeline is connected to the four silicon preheaters and the four silicon vaporizers and is used for heating and raising the temperature of the chlorosilane required before the hydrogenation furnace reacts.

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