Waste heat utilization device of polycrystalline silicon production system

Abstract

The utility model provides a waste heat utilization device of a polycrystalline silicon production system, which relates to the technical field of polycrystalline silicon, and comprises a waste heat power generation mechanism, a waste heat utilization device, a waste heat utilization device and a waste heat utilization device, the power output end of the waste heat power generation mechanism is electrically connected with a power distribution system of a factory; and the first condensation path is used for condensing the rich steam passing through the waste heat power generation mechanism to obtain condensed water, and the condensed water is sent back to the polycrystalline silicon production system through a water return pipeline. Through the arrangement of the waste heat power generation mechanism, waste heat of rich steam is fully recycled, the mode of grid-connected operation of the waste heat recycling device and the plant power distribution system is adopted, power supply nearby can be achieved, the load of electric equipment with the power distribution system can be achieved, the needed length of a cable for power supply nearby is the shortest, and one-time investment is low.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon, in particular to a waste heat utilization device of a polysilicon production system. Background Art

[0002] In the technology of producing polysilicon by the modified Siemens method, the surplus of rich steam generated by the distillation and reduction sections of the polysilicon production system is relatively large, and can reach up to nearly 200t / h. Rich steam cannot be directly returned to the polysilicon production system (distillation and reduction sections) for reuse due to its high temperature. The current conventional practice is to use circulating water, air cooling and other methods to exchange heat, lower the temperature to condense it, and then return it to the system in the form of condensed water. This results in: on the one hand, the circulating water and air used for heat exchange take away the heat energy in the system, causing energy waste; on the other hand, system equipment such as steam condensate water heat exchange equipment, circulating water cooling tower, and air cooler increase the primary investment cost and subsequent maintenance cost, and do not generate economic benefits. Utility Model Content

[0003] In view of the above situation, the utility model provides a waste heat utilization device for a polysilicon production system, aiming to solve the technical problems that, on the one hand, the circulating water, air, etc. used for heat exchange take away the heat energy in the system, causing energy waste; on the other hand, the steam condensate heat exchange equipment, circulating water cooling tower, air cooler and other system equipment increase the primary investment cost and subsequent maintenance cost, and do not generate economic benefits.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] The utility model provides a waste heat utilization device for a polysilicon production system, comprising:

[0006] A waste heat power generation mechanism, the air inlet of which is connected to a polysilicon production system, and the polysilicon production system generates steam; and an electric power output end of the waste heat power generation mechanism is electrically connected to a power distribution system of a plant area;

[0007] The first condensation path is used to condense the rich steam after passing through the waste heat power generation mechanism to obtain condensed water, and the condensed water is returned to the polysilicon production system through a return water pipe.

[0008] In some embodiments of the present invention, the waste heat power generation mechanism includes a steam turbine and a generator that are transmission-connected.

[0009] In some embodiments of the present invention, the first condensation path includes a first condenser, and the first condenser has a first circulating water pipeline for providing cold energy.

[0010] In some embodiments of the present invention, a second condensation path connected in parallel with the waste heat power generation mechanism is also included; the second condensation path is used to condense the rich steam that has not passed through the waste heat power generation mechanism to obtain condensed water, and the condensed water is returned to the polysilicon production system through a return water pipe.

[0011] In some embodiments of the present invention, the second condensation path includes a second condenser, and the second condenser has a second circulating water pipeline for providing cold energy.

[0012] In some embodiments of the present invention, a cooling mechanism is further included, which is used to cool the heat exchange circulating water in the first circulating water pipeline and / or the second circulating water pipeline.

[0013] In some embodiments of the present invention, the temperature reduction mechanism includes a cooling tower.

[0014] In some embodiments of the present invention, the cooling tower adopts an open spray cooling structure, and the inlet of the cooling tower is located at the upper part thereof, and the outlet is located at the lower part thereof.

[0015] In some embodiments of the utility model, a gas-liquid separation tank is also included; the inlet of the gas-liquid separation tank is connected to the polysilicon production system, and the gas phase outlet of the gas-liquid separation tank is connected to the air inlet end of the waste heat power generation mechanism.

[0016] In some embodiments of the utility model, the gas phase outlet of the gas-liquid separation tank is connected to an emergency venting pipe, and a muffler is provided on the emergency venting pipe.

[0017] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0018] 1. Through the setting of waste heat power generation mechanism, the waste heat of steam-rich products is fully recovered and utilized, and the waste heat recovery and utilization device is connected to the power distribution system of the plant area to realize the nearby power supply to carry the load of the power equipment of the distribution system, and the required length of the cable for the nearby power supply is the shortest, and the one-time investment is low.

[0019] 2. The first condensation path is used to exchange heat and condense the rich steam after passing through the waste heat power generation mechanism, and to reuse the generated condensed water in the polysilicon production system.

[0020] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 description of the embodiments 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 any creative work.

[0022] Figure 1 This is a schematic diagram of the structure of a waste heat utilization device in a polysilicon production system.

[0023] icon:

[0024] 11-steam turbine, 12-generator, 13-coupling,

[0025] 21- first condenser, 22- first water pump, 23- first circulating water pipeline,

[0026] 31-second condenser, 32-second water pump, 33-second circulating water pipeline,

[0027] 4- Return pipe,

[0028] 5- Cooling tower,

[0029] 61-gas-liquid separation tank, 62-emergency vent pipe, 63-muffler. DETAILED DESCRIPTION

[0030] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0031] In the description of the embodiments of the present utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected 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 embodiments of the present invention can be understood according to specific circumstances.

[0033] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0034] Example 1

[0035] See also Figure 1 This embodiment provides a waste heat utilization device for a polysilicon production system, including a waste heat power generation mechanism, a first condensation path, a second condensation path and a cooling mechanism.

[0036] The waste heat power generation mechanism uses the rich steam to generate electricity; the air intake end of the waste heat power generation mechanism is connected to the polysilicon production system, and the polysilicon production system generates rich steam; the power output end of the waste heat power generation mechanism is electrically connected to the power distribution system of the plant area. Specifically, the waste heat power generation mechanism includes a steam turbine 11 and a generator 12 that are transmission-connected. The steam turbine 11 and the generator 12 are all very mature equipment. The air intake end of the steam turbine 11 is connected to the polysilicon production system, and the power output end of the steam turbine 11 is connected to the power input end of the generator 12 through a coupling 13. The power output end of the generator 12 is electrically connected to the power distribution system of the plant area through a cable. In this embodiment, preferably, the waste heat power generation mechanism includes multiple groups of steam turbines 11 and generators 12.

[0037] The above-mentioned polysilicon production system includes a distillation section and a reduction section.

[0038] Through the setting of the waste heat power generation mechanism, the waste heat recovery and utilization device is connected to the power distribution system of the factory area, and the power supply can be supplied nearby to carry the load of the power equipment of the distribution system. The required length of the cable for the nearby power supply is the shortest, and the one-time investment is low.

[0039] The first condensation path is used to exchange heat and condense the rich steam after passing through the waste heat power generation mechanism. Specifically, the first condensation path includes a first condenser 21 and a first water pump 22. The waste heat power generation mechanism, the first condenser 21 and the first water pump 22 are connected in series in sequence; the gas phase inlet of the first condenser 21 is connected to the gas outlet of the turbine 11, and the liquid phase outlet of the first condenser 21 is connected to the return water pipe 4 through the first water pump 22, and the return water pipe 4 is used to return the condensed water to the above-mentioned polysilicon production system. The first condenser 21 has a first circulating water pipe 23 for providing cooling capacity.

[0040] The second condensation path is connected in parallel with the waste heat power generation mechanism. The second condensation path serves as a backup condensation path. When the waste heat power generation mechanism fails, the rich steam that has not passed through the waste heat power generation mechanism is directly condensed to avoid fluctuations in the corresponding steam network caused by the failure of the waste heat power generation mechanism, thereby avoiding fluctuations in the process of the polysilicon production system. Specifically, the second condensation path includes a second condenser 31 and a second water pump 32. The gas phase inlet of the second condenser 31 is connected to the polysilicon production system, and the liquid phase outlet of the second condenser 31 is connected to the return water pipe 4 through the second water pump 32; preferably, the condensed water from the first condenser 21 and the second condenser 31 is sent back to the above-mentioned polysilicon production system through the same return water pipe 4. The second condenser 31 has a second circulating water pipe 33 for providing cooling.

[0041] The cooling mechanism is used to cool the heat exchange circulating water in the first circulating water pipeline 23 and / or the second circulating water pipeline 33. The cooling mechanism includes a cooling tower 5 connected to the first circulating water pipeline 23 and / or the second circulating water pipeline 33. In this embodiment, preferably, the cooling tower 5 adopts an open spray cooling structure, the inlet of the cooling tower 5 is located at its upper part, and the outlet is located at its lower part, the two ends of the first circulating water pipeline 23 are respectively connected to the inlet and outlet of the cooling tower 5, and the two ends of the second circulating water pipeline 33 are also respectively connected to the inlet and outlet of the cooling tower 5. In this way, the heat exchange circulating water can exchange heat with the air and cool in the process of falling in the cooling tower 5, so as to maintain the temperature of the heat exchange circulating water in the first and second circulating water pipelines 33 in a low energy consumption manner.

[0042] In combination with the above content, this embodiment has at least the following beneficial effects:

[0043] 1. There is no precedent for the polysilicon industry to use the heat of rich steam to generate electricity. This embodiment converts the heat of rich steam into electrical energy through the setting of waste heat power generation mechanism, fully recovers and utilizes the waste heat of rich steam, and adopts the mode of grid-connected operation of waste heat recovery and utilization device and plant power distribution system, which can realize the nearby power supply to carry the load of electrical equipment of the power distribution system, and the required length of the cable for nearby power supply is the shortest, the one-time investment is low, and the investment cost recovery is fast.

[0044] 2. The first condensation path is used to exchange heat and condense the rich steam after passing through the waste heat power generation mechanism, and to reuse the generated condensed water in the polysilicon production system.

[0045] 3. The second condensation path is connected in parallel with the waste heat power generation mechanism. The second condensation path serves as a backup condensation path. When the waste heat power generation mechanism fails, the second condensation path is used to directly condense the rich steam and reuse the rich steam in the form of condensed water to avoid fluctuations in the steam network caused by the failure of the waste heat power generation mechanism, thereby avoiding fluctuations in the polysilicon production system process.

[0046] Fourth, the cooling tower 5 adopts an open spray cooling structure, the inlet of the cooling tower 5 is located at the upper part of the cooling tower 5, and the outlet is located at the lower part of the cooling tower 5, which can maintain the temperature of the heat exchange circulating water in the circulating water pipeline in a low energy consumption manner. The overall power consumption of the device is low.

[0047] In other embodiments, the first condenser 21 and the second condenser 31 may also adopt other relatively high energy consumption methods to exchange heat with the rich product steam.

[0048] Example 2

[0049] The difference between this embodiment and Embodiment 1 is that the waste heat utilization device of the polysilicon production system further includes a gas-liquid separation tank 61 , an emergency venting pipe 62 and a muffler 63 .

[0050] The inlet of the gas-liquid separation tank 61 is connected to the polysilicon production system, and the gas phase outlet of the gas-liquid separation tank 61 is connected to the air inlet of the steam turbine 11. By setting the gas-liquid separation tank 61, the moisture in the rich steam can be separated. The advantages of such setting are: ① The purity and quality of the rich steam are improved, which helps to reduce the corrosion and fouling inside the steam turbine 11 and maintain the efficiency and performance of the steam turbine 11; ② Avoid water hammer to damage the blades and internal structure of the steam turbine 11, which is conducive to the stable operation of the steam turbine 11; ③ Excessive moisture will reduce the thermal efficiency of steam. By separating the moisture, it can ensure that the steam entering the steam turbine 11 is drier, thereby improving the conversion efficiency of thermal energy, so that the steam turbine 11 can more effectively convert thermal energy into mechanical energy.

[0051] The emergency venting pipeline 62 is connected to the gas phase outlet of the gas-liquid separation tank 61 so as to vent in an emergency to ensure the safety of the device.

[0052] The silencer 63 is arranged on the emergency venting pipe 62 to reduce the noise during venting.

[0053] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be combined with each other at will. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A waste heat utilization device for a polysilicon production system, characterized in that: include: A waste heat power generation mechanism, the air inlet of which is connected to a polysilicon production system, the polysilicon production system generates steam; the power output of the waste heat power generation mechanism is electrically connected to a power distribution system of the plant area; The first condensation path is used to condense the rich steam after passing through the waste heat power generation mechanism to obtain condensed water, and return the condensed water to the polysilicon production system through a return water pipeline.

2. The waste heat utilization device of the polysilicon production system according to claim 1, characterized in that: The waste heat power generation mechanism comprises a steam turbine and a generator which are transmission-connected.

3. The waste heat utilization device of the polysilicon production system according to claim 1, characterized in that: The first condensation path includes a first condenser having a first circulating water pipeline for providing cold energy.

4. The waste heat utilization device of the polysilicon production system according to claim 3, characterized in that: It also includes a second condensation path connected in parallel with the waste heat power generation mechanism; the second condensation path is used to condense the rich steam that has not passed through the waste heat power generation mechanism to obtain condensed water, and the condensed water is returned to the polysilicon production system through a return water pipe.

5. The waste heat utilization device of the polysilicon production system according to claim 4, characterized in that: The second condensation path includes a second condenser having a second circulating water pipeline for providing cold energy.

6. The waste heat utilization device of the polysilicon production system according to claim 5, characterized in that: It also includes a cooling mechanism, which is used to cool the heat exchange circulating water in the first circulating water pipeline and / or the second circulating water pipeline.

7. The waste heat utilization device of the polysilicon production system according to claim 6, characterized in that: The temperature reduction mechanism includes a cooling tower.

8. The waste heat utilization device of the polysilicon production system according to claim 7, characterized in that: The cooling tower adopts an open spray cooling structure, the inlet of the cooling tower is located at the upper part thereof, and the outlet is located at the lower part thereof.

9. The waste heat utilization device of the polysilicon production system according to any one of claims 1 to 8, characterized in that: It also includes a gas-liquid separation tank; the inlet of the gas-liquid separation tank is connected to the polysilicon production system, and the gas phase outlet of the gas-liquid separation tank is connected to the air inlet end of the waste heat power generation mechanism.

10. The waste heat utilization device of the polysilicon production system according to claim 9, characterized in that: The gas phase outlet of the gas-liquid separation tank is connected to an emergency venting pipeline, and a muffler is arranged on the emergency venting pipeline.

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