A thermal energy utilization system having a vaporizer

Abstract

The utility model provides a kind of heat energy utilization system with vaporizer, it is related to vaporizer technical field, it includes: reduction furnace, it is used to generate high-temperature tail gas;Tail gas cooling device, it is used to cool tail gas;Silicon powder filter, it is used to filter tail gas;Vaporizer, it has tail gas air inlet and tail gas outlet, vaporizer is communicated with the air outlet of silicon powder filter by tail gas air inlet, for the entry of filtered tail gas and with high heat in tail gas Heat exchange treatment;Recovery condensing system, it is used to absorb tail gas discharged by vaporizer and condenses it into liquid;Adsorption column, it is used to adsorb the hydride remaining in recovery condensing system;Wherein, reduction furnace, tail gas cooling device, silicon powder filter, vaporizer, recovery condensing system and adsorption column are sequentially communicated by communication pipeline, and the system can utilize the heat energy of reduction tail gas, can effectively reduce the steam amount required for vaporizer heating silicon tetrachloride, reach the effect of energy saving.

Description

Technical Field

[0001] This utility model relates to the field of vaporizer technology, specifically to a thermal energy utilization system with a vaporizer. Background Technology

[0002] Currently, in the cold hydrogenation process, steam heating is required to bring the temperature of silicon tetrachloride gas at the vaporizer outlet to about 160°C. In this process, the vaporizer requires a large amount of steam, which leads to an increase in the energy consumption required in the overall process. Utility Model Content

[0003] This invention addresses the problem of high energy consumption caused by the large amount of steam required for heating in the vaporizer during cold hydrogenation production. It provides a thermal energy utilization system with a vaporizer that can utilize the thermal energy of the reduction tail gas, effectively reducing the amount of steam required for heating silicon tetrachloride in the vaporizer and achieving energy savings.

[0004] The technical solution adopted in this utility model is:

[0005] A thermal energy utilization system with a vaporizer is provided, comprising:

[0006] The system comprises: a reduction furnace for heating and melting silicon powder and generating exhaust gas; an exhaust gas cooling device for absorbing and cooling the exhaust gas from the reduction furnace; a silicon powder filter for filtering out silicon powder from the cooled exhaust gas; a vaporizer with an exhaust gas inlet and outlet, connected to the outlet of the silicon powder filter via the exhaust gas inlet, for allowing the filtered exhaust gas to enter and exchange heat with the high heat in the exhaust gas; a recovery condensation system for absorbing and condensing the heat-exchanged exhaust gas into a liquid; and an adsorption column for adsorbing and recovering residual hydrides from the condensation system. The reduction furnace, exhaust gas cooling device, silicon powder filter, vaporizer, recovery condensation system, and adsorption column are all connected by several connecting pipes.

[0007] Optionally, a first parallel pipeline is provided between the gas outlet of the reduction furnace and the gas inlet of the silicon powder filter, and the first parallel pipeline is connected in parallel with the tail gas cooling device; a first regulating valve is provided on the connecting pipeline between the reduction furnace and the tail gas cooling device, and a second regulating valve is provided on the first parallel pipeline.

[0008] Optionally, a second parallel pipeline is provided between the silicon powder filter and the recovery condensation system, and the second parallel pipeline is connected in parallel with the vaporizer; a third regulating valve is provided on the connecting pipeline between the silicon powder filter and the vaporizer, and a fourth regulating valve is provided on the second parallel pipeline.

[0009] Optionally, a connecting pipe for steam auxiliary air intake is provided on the connecting pipeline between the silicon powder filter and the vaporizer. One end of the steam auxiliary air intake pipe is used to input steam, and the other end is used to output steam to the interior of the vaporizer. A temperature and pressure compensator is provided on the steam auxiliary air intake pipe. When the temperature of the exhaust gas entering the vaporizer is lower than 500°C, steam is introduced for auxiliary heating.

[0010] Optionally, the vaporizer has a heat exchange unit inside, which includes a double-layered tube. The inner tube of the double-layered tube is used to transport silicon tetrachloride gas, and the space between the inner and outer tubes of the double-layered tube is used to transport exhaust gas. The flow direction of the silicon tetrachloride gas is opposite to that of the exhaust gas.

[0011] Optionally, the double-layer sleeve is a Hastelloy C276 sleeve with a wall thickness of 2.5 to 3.5 mm and a spacing of 15 to 25 mm between the outer and inner sleeves.

[0012] Optionally, a temperature sensor is provided at the outlet of the vaporizer to output silicon tetrachloride gas, for detecting the temperature of the output silicon tetrachloride gas.

[0013] Optionally, the vaporizer is externally equipped with a controller electrically connected to a temperature sensor. The controller is electrically connected to the first regulating valve, the second regulating valve, the third regulating valve, and the fourth regulating valve, and performs dynamic regulation.

[0014] Optionally, the vaporizer is externally equipped with a connected electric heater for heating the vaporizer during the initial operation phase.

[0015] Optionally, a gas-solid separator is provided on the connecting line between the third regulating valve and the vaporizer.

[0016] The beneficial effects of this utility model are:

[0017] In the process of recovering polysilicon reduction tail gas, the tail gas generated by the reduction furnace through heating and melting silicon powder will first undergo preliminary cooling treatment through a tail gas cooling device. After treatment, the tail gas will be filtered out of the silicon powder contained in the tail gas through a silicon powder filter. Then, the tail gas will be sent to the recovery condensation system to be condensed into liquid. During the tail gas recovery condensation process, the adsorption column can adsorb the residual hydrides in the recovery condensation system. In the above process, the vaporizer is connected between the silicon powder filter and the recovery condensation system. Since the exhaust gas generated by the reduction furnace heating and melting silicon powder is at a high temperature, the high-temperature exhaust gas is introduced into the vaporizer, allowing the silicon tetrachloride gas inside the vaporizer to exchange heat with the high-temperature exhaust gas, thereby increasing the temperature of the silicon tetrachloride gas. After the heat exchange with the high-temperature exhaust gas is completed, the heat-exchanged exhaust gas is then introduced into the recovery condensation system for condensation treatment. Compared to the large amount of steam heat required when the vaporizer heats the silicon tetrachloride gas, connecting the vaporizer to the polycrystalline silicon reduction exhaust gas recovery process can make reasonable use of the high-temperature reduction exhaust gas. After the high-temperature reduction exhaust gas is utilized, its temperature drops, and the subsequent recovery condensation system can also be used to condense the reduction exhaust gas, achieving the effect of saving energy consumption. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a schematic diagram of a heat energy utilization system with a vaporizer disclosed in this embodiment.

[0020] Figure 2 This is a top-down view of the vaporizer, including the vaporizer, steam-assisted air inlet pipe, compensator, temperature sensor, controller, electric heater, and gas-solid separator.

[0021] Figure 3 This is a schematic diagram of the main structure of the double-layer sleeve.

[0022] Figure label:

[0023] 1-First regulating valve;

[0024] 2-First parallel pipeline, 20-Second regulating valve;

[0025] 3-Third regulating valve;

[0026] 4-Second parallel pipeline, 40-Fourth regulating valve;

[0027] 5-Vaporizer, 50-Electric heater, 51-Double sleeve;

[0028] 6-Steam auxiliary air inlet pipe, 60-Temperature and pressure compensator;

[0029] 7-Temperature sensor;

[0030] 8-Controller;

[0031] 9-Gas-solid separator. Detailed Implementation

[0032] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0033] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0034] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0035] Example

[0036] Please see Figure 1-3As shown, this embodiment discloses a thermal energy utilization system with a vaporizer, including a reduction furnace, a tail gas cooling device, a silicon powder filter, a recovery condensation system, and an adsorption column connected in sequence, wherein the connections are made up of several connecting pipes. The reduction furnace is used to heat and melt silicon powder and generate tail gas, which enters the tail gas cooling device for preliminary cooling. The cooled tail gas contains silicon powder, which is then filtered through the connected silicon powder filter. The treated tail gas then enters the recovery condensation system for condensation. During the condensation process in the recovery condensation system, the adsorption column adsorbs the hydrides remaining in the recovery condensation system and recycles the recovered hydrides back into the reduction furnace for reuse. A vaporizer 5 is connected to the connecting pipe between the silicon powder filter and the recovery condensation system. The function of the vaporizer 5 is to heat silicon tetrachloride gas. Currently, the method used is to heat the silicon tetrachloride gas by inputting a large amount of steam, so that the temperature of the silicon tetrachloride gas at the outlet of the vaporizer 5 reaches about 160°C. After the vaporizer 5 is connected between the silicon powder filter and the recovery condensation system, the exhaust gas filtered by the silicon powder filter will enter the interior of the vaporizer 5 through the corresponding connecting pipe, so that the high-temperature reduction exhaust gas and silicon tetrachloride gas can exchange heat, thereby increasing the temperature of silicon tetrachloride gas. Compared with using a large amount of steam to heat silicon tetrachloride gas, the rational use of high-temperature reduction exhaust gas can reduce energy consumption.

[0037] A first parallel pipeline 2 is connected between the reduction furnace and the silicon powder filter. The first parallel pipeline 2 is connected in parallel with the exhaust gas cooling device. Specifically, a first regulating valve 1 is installed on the connecting pipeline between the reduction furnace and the exhaust gas cooling device. The first regulating valve 1 can regulate the exhaust gas entering the exhaust gas cooling device. In addition, a second regulating valve 20 is provided on the first parallel pipeline 2. One end of the first parallel pipeline 2 is located on the connecting pipeline between the reduction furnace and the first regulating valve 1, and the other end is located on the connecting pipeline between the tail gas cooling device and the silicon powder filter. That is, the tail gas cooling device cools the tail gas, causing the temperature of the tail gas delivered from the reduction furnace to drop. When this part of the tail gas with a lower temperature enters the vaporizer 5 after being filtered by the silicon powder filter, the heat that can be provided to the silicon tetrachloride gas for heat exchange will be reduced. To address this, by closing the first regulating valve 1 located between the reduction furnace and the tail gas cooling device and opening the second regulating valve 20 on the first parallel pipeline 2, the high-temperature reduction tail gas generated by the reduction furnace can directly enter the silicon powder filter for filtration without being cooled by the tail gas cooling device. The filtered high-temperature reduction tail gas will then enter through the tail gas inlet of the vaporizer 5 and exchange heat with the silicon tetrachloride gas introduced into the vaporizer 5, thereby causing the temperature of the silicon tetrachloride gas to rise faster. After the exhaust gas in the vaporizer 5 undergoes heat exchange treatment, it is discharged through the exhaust gas outlet of the vaporizer 5. The exhaust gas discharged after heat exchange in the vaporizer 5 will then enter the recovery and condensation system for condensation treatment.

[0038] A second parallel pipeline 4 is provided between the silicon powder filter and the recovery condensation system. The second parallel pipeline 4 is connected in parallel with the vaporizer 5. A third regulating valve 3 is provided on the connecting pipeline between the silicon powder filter and the vaporizer 5, and a fourth regulating valve 40 is provided on the second parallel pipeline 4. One end of the second parallel pipeline 4 is located between the silicon powder filter and the third regulating valve 3, and the other end is located on the connecting pipeline between the vaporizer 5 and the recovery condensation system. Because the high-temperature reduction tail gas discharged from the reduction furnace has a large volume, only a small portion of it can be used in the vaporizer 5. At this time, by adjusting the opening of the third regulating valve 3 and the fourth regulating valve 40, a small portion of the high-temperature reduction tail gas filtered by the silicon powder filter continuously enters the recovery and condensation system through the fourth regulating valve 40. The small portion of tail gas continuously enters the vaporizer 5 through the third regulating valve 3 and exchanges heat with the silicon tetrachloride gas. After the small portion of tail gas completes the heat exchange operation inside the vaporizer 5, it will be discharged from the tail gas outlet of the vaporizer 5 and enter the recovery and condensation system for condensation treatment.

[0039] In the aforementioned thermal energy utilization system with a vaporizer, a connected steam auxiliary inlet pipe 6 is provided on the connecting pipeline between the silicon powder filter and the vaporizer 5. One end of the steam auxiliary inlet pipe 6 is used to input steam, and the other end delivers steam to the interior of the vaporizer 5. When the temperature of the exhaust gas entering the vaporizer 5 is below 500°C, steam can be introduced into the steam auxiliary inlet pipe 6 to assist heating, raising the temperature of the exhaust gas in the vaporizer 5 to above 500°C to complete the heat exchange with the silicon tetrachloride gas. Furthermore, to facilitate adjustment of the steam input in the steam auxiliary inlet pipe 6, a temperature and pressure compensator 60 is installed on the steam auxiliary inlet pipe 6. This compensator can actively adjust the steam input based on the temperature of the exhaust gas entering the vaporizer 5, ensuring that the temperature of the exhaust gas entering the vaporizer 5 meets the heat exchange temperature required by the silicon tetrachloride gas.

[0040] The vaporizer 5 described above has an internal heat exchange unit for heat exchange between the exhaust gas and silicon tetrachloride gas. Specifically, the heat exchange unit includes a double-layered sleeve 51. The inner tube of the double-layered sleeve 51 is used to transport silicon tetrachloride gas, and the space between the inner and outer tubes is used to transport the exhaust gas entering the vaporizer 5. The direction of exhaust gas transport is opposite to that of silicon tetrachloride gas transport, allowing for better heat exchange between the exhaust gas and silicon tetrachloride gas. Furthermore, in this embodiment, the double-layered sleeve 51 is made of Hastelloy C276. Hastelloy C276 has good corrosion resistance, and its use here to transport reducing exhaust gas and silicon tetrachloride gas can prevent the double-layered sleeve 51 from being corroded, thus affecting the heat exchange between the reducing exhaust gas and silicon tetrachloride gas.

[0041] A temperature sensor 7 is installed at the outlet of the vaporizer 5 where silicon tetrachloride gas is output. The temperature sensor 7 can display the temperature of the silicon tetrachloride gas discharged from the outlet of the vaporizer 5. When the temperature of the discharged silicon tetrachloride gas is not between 155°C and 165°C, the opening of the first regulating valve 1, the second regulating valve 20, the third regulating valve 3 and the fourth regulating valve 40 are manually adjusted to adjust the temperature of the silicon tetrachloride gas discharged from the vaporizer 5 to a suitable temperature range. In addition, to save time in adjusting different valves, a controller 8 is installed outside the vaporizer 5. The controller 8 is either a PID controller 8 or a PLC controller 8. The controller 8 is electrically connected to the temperature sensor group 7, and is also electrically connected to the first regulating valve 1, the second regulating valve 20, the third regulating valve 3, and the fourth regulating valve 40, respectively. That is, the temperature value of the silicon tetrachloride gas output from the vaporizer 5 detected by the temperature sensor 7 is used to dynamically adjust each regulating valve. When the silicon tetrachloride gas temperature is too high, the controller 8 adjusts the opening of the valves at different positions to decrease, thereby reducing the input flow of the exhaust gas. When the silicon tetrachloride gas temperature is too low, the controller 8 adjusts the opening of the regulating valves at different positions to increase, thereby increasing the input flow of the exhaust gas.

[0042] An electric heater 50 is installed outside the vaporizer 5 to assist in heating the silicon tetrachloride gas inside the vaporizer 5. Specifically, during the initial heating of the silicon tetrachloride gas, the temperature that can be applied to the silicon tetrachloride gas is difficult to reach a suitable temperature value, so the electric heater 50 is needed to assist in heating so that the temperature value of the silicon tetrachloride gas discharged in the initial heating stage can reach between 155 and 165°C.

[0043] A gas-solid separator 9 is installed on the connecting pipeline between the third regulating valve 3 and the vaporizer 5. The gas-solid separator 9 can filter out solid particles other than those filtered out by the silica powder filter in the exhaust gas.

[0044] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thermal energy utilization system with a vaporizer, characterized in that, include: A reduction furnace is used to heat and melt silicon powder and generate exhaust gas; an exhaust gas cooling device is used to absorb the exhaust gas generated by the reduction furnace and cool it down. A silicon powder filter is used to filter out silicon powder from the cooled exhaust gas; a vaporizer has an exhaust gas inlet and an exhaust gas outlet, the vaporizer being connected to the outlet of the silicon powder filter through the exhaust gas inlet, for the filtered exhaust gas to enter and exchange heat with the high heat in the exhaust gas; a recovery condensation system is used to absorb and condense the heat-exchanged exhaust gas into a liquid; an adsorption column is used to adsorb the hydrides remaining in the recovery condensation system; wherein, the reduction furnace, the exhaust gas cooling device, the silicon powder filter, the vaporizer, the recovery condensation system, and the adsorption column are sequentially connected by several connecting pipes.

2. The thermal energy utilization system with a vaporizer according to claim 1, characterized in that, A first parallel pipeline is provided between the gas outlet of the reduction furnace and the gas inlet of the silicon powder filter, and the first parallel pipeline is connected in parallel with the tail gas cooling device; a first regulating valve is provided on the connecting pipeline between the reduction furnace and the tail gas cooling device, and a second regulating valve is provided on the first parallel pipeline.

3. The thermal energy utilization system with a vaporizer according to claim 2, characterized in that, A second parallel pipeline is provided between the silicon powder filter and the recovery condensation system, and the second parallel pipeline is connected in parallel with the vaporizer; a third regulating valve is provided on the connecting pipeline between the silicon powder filter and the vaporizer, and a fourth regulating valve is provided on the second parallel pipeline.

4. The thermal energy utilization system with a vaporizer according to claim 3, characterized in that, The connecting pipeline between the silicon powder filter and the vaporizer is also provided with a steam auxiliary air inlet pipe. One end of the steam auxiliary air inlet pipe is used to input steam, and the other end is used to output steam to the interior of the vaporizer. The steam auxiliary air inlet pipe is provided with a temperature and pressure compensator. When the temperature of the exhaust gas entering the vaporizer is lower than 500°C, steam is introduced for auxiliary heating.

5. The thermal energy utilization system with a vaporizer according to claim 4, characterized in that, The vaporizer has a heat exchange unit inside, which includes a double-layered sleeve. The inner tube of the double-layered sleeve is used to transport silicon tetrachloride gas, and the space between the inner and outer tubes of the double-layered sleeve is used to transport exhaust gas. The flow direction of the silicon tetrachloride gas is opposite to that of the exhaust gas.

6. The thermal energy utilization system with a vaporizer according to claim 5, characterized in that, The double-layer sleeve is a Hastelloy C276 sleeve with a wall thickness of 2.5 to 3.5 mm and a spacing of 15 to 25 mm between the outer and inner sleeves.

7. The thermal energy utilization system with a vaporizer according to claim 3, characterized in that, A temperature sensor is installed at the outlet of the vaporizer that outputs silicon tetrachloride gas to detect the temperature of the output silicon tetrachloride gas.

8. The thermal energy utilization system with a vaporizer according to claim 7, characterized in that, The vaporizer is externally equipped with a controller that is electrically connected to the temperature sensor. The controller is electrically connected to the first regulating valve, the second regulating valve, the third regulating valve, and the fourth regulating valve, and performs dynamic adjustment.

9. The thermal energy utilization system with a vaporizer according to claim 3, characterized in that, The vaporizer is externally equipped with a connected electric heater for heating the vaporizer during the initial operation phase.

10. The thermal energy utilization system with a vaporizer according to claim 3, characterized in that, A gas-solid separator is provided on the connecting pipeline between the third regulating valve and the vaporizer.

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