Tail gas waste heat utilization device of polycrystalline silicon reduction furnace

Abstract

The utility model belongs to the technical field of polycrystalline silicon reduction furnaces, and particularly relates to a tail gas waste heat utilization device of a polycrystalline silicon reduction furnace, which comprises a reduction furnace, a tail gas discharge port of the reduction furnace is connected with a tail gas coil pipe, and the other end of the tail gas coil pipe is connected with a first jacket mechanism. The other end of the first jacket mechanism is connected with a second jacket mechanism through a connecting pipe, the other end of the second jacket mechanism is connected to a tail gas pipe, the other end of the tail gas pipe is connected to a tail gas main pipe, and the tail gas main pipe is connected to a hydrogen preheater. Through the tail gas coil pipe, the jacket mechanism I and the jacket mechanism II, cooling water is flashed into saturated steam with different pressures to be used by a workshop, so that the production cost of the workshop is reduced; the tail gas is introduced into the hydrogen preheater to preheat the hydrogen in the hydrogen preheater, and after the hydrogen enters the reduction furnace to react due to the temperature rise of the hydrogen, the heat absorption can be reduced, and the reaction power consumption is further reduced.

Description

TECHNICAL FIELD

[0001] The scheme belongs to the field of polycrystalline silicon reduction furnace, and particularly relates to a tail gas waste heat utilization device of a polycrystalline silicon reduction furnace. BACKGROUND

[0002] The document of the National Development and Reform Commission (No. 509 of 2005) clearly requires that the "Renewable Energy and New Energy High-tech Industrialization Special Project" be organized and implemented, and clearly proposes that the problem of imbalance between the production of polycrystalline silicon raw materials for solar cells and the development of the photovoltaic industry chain be solved. The polycrystalline silicon industry, which is the basic raw material for the solar industry, has production lines of different sizes such as 100 tons, 300 tons, and 1000 tons. The reduction furnace used mainly has 9 pairs of rods and 12 pairs of rods. In the following more than 10 years, the polycrystalline silicon industry has experienced a cruel market elimination and industrial technological innovation. The production equipment and process route have completed a leap-forward upgrade, and the production cost of polycrystalline silicon has decreased from 60 US dollars per kilogram to 10 US dollars per kilogram.

[0003] The reduction furnace type mainly has 36 pairs of rods and 40 pairs of rods. From the development technology of polycrystalline silicon, it seems to have entered a bottleneck period. Most people in the industry believe that the scale and technology of polycrystalline silicon production have already been very mature and there is no possibility of further optimization. In such an environment, cost saving is the trend of the times. At present, the utilization of thermal energy is in the stage of large-scale promotion. However, the utilization of reduction tail gas waste heat is a common problem in the photovoltaic industry, which seriously affects the production cost of polycrystalline silicon. Therefore, it is extremely crucial to improve the utilization of reduction tail gas waste heat. CONTENT OF THE UTILITY MODEL

[0004] The purpose of the scheme is to provide a tail gas waste heat utilization device of a polycrystalline silicon reduction furnace to solve the problem of tail gas waste heat utilization.

[0005] In order to achieve the above purpose, the scheme provides a tail gas waste heat utilization device of a polycrystalline silicon reduction furnace, which comprises a reduction furnace. A tail gas coil is connected to the tail gas discharge port of the reduction furnace. The other end of the tail gas coil is connected to a jacket mechanism one. The other end of the jacket mechanism one is connected to a jacket mechanism two through a connecting pipe. The other end of the jacket mechanism two is connected to a tail gas pipe. The other end of the tail gas pipe is connected to a tail gas main pipe. The tail gas main pipe is connected to a hydrogen preheater.

[0006] The principle of the scheme is that when in use, the tail gas of the reduction furnace is discharged into the tail gas coil, so that the high-temperature tail gas heats the cooling water at the outer pipe of the tail gas coil to obtain saturated steam. With the continuous flow of the tail gas, the tail gas passes through the jacket mechanism one and the jacket mechanism two and heats the cooling water on the outer pipe of the jacket mechanism to obtain saturated steam again. Finally, the tail gas flows into the hydrogen preheater.

[0007] The technical effects of the present scheme are that the cooling water is flashed into saturated steam of different pressures through the tail gas coil, the jacket mechanism one and the jacket mechanism two to supply the workshop, thereby reducing the production cost of the workshop; the hydrogen gas is preheated by passing the tail gas into the hydrogen gas preheater, and the increase of the hydrogen gas temperature can reduce heat absorption after the hydrogen gas enters the reduction furnace for reaction, thereby reducing the reaction power consumption.

[0008] Further, the tail gas coil is connected with the water inlet pipe one and the water outlet pipe one respectively, and the water outlet pipe one is connected with the bottom plate flash tank. The bottom plate flash tank can flash 0.2MPa steam for use in other workshops.

[0009] Further, the jacket mechanism one comprises a heat conducting pipe one, one end of the heat conducting pipe one is connected with the tail gas coil and the other end is fixed with the connecting pipe, the outer side of the heat conducting pipe one is provided with a sleeve one, the end of the sleeve one is fixed with the heat conducting pipe one through the connecting plate one, the heat conducting pipe one is provided with a spiral condensing pipe one, the condensing pipe one is spirally wound on the heat conducting pipe one, and the two ends of the condensing pipe one are connected with the water inlet pipe two and the water outlet pipe two respectively. The spiral condensing pipe one improves the contact between the condensing pipe one and the heat conducting pipe one, so that the cooling water in the condensing pipe one can be fully heated.

[0010] Further, the jacket mechanism two comprises a heat conducting pipe two, one end of the heat conducting pipe two is fixed with the connecting pipe and the other end is connected with the tail gas pipe, the outer side of the heat conducting pipe two is provided with a sleeve two, the end of the sleeve two is fixed with the heat conducting pipe two through the connecting plate two, the heat conducting pipe two is provided with a spiral condensing pipe two, the condensing pipe two is spirally wound on the heat conducting pipe two, and the two ends of the condensing pipe two are connected with the water inlet pipe three and the water outlet pipe three respectively. The spiral condensing pipe two allows the condensing pipe two and the heat conducting pipe two to have more contact surfaces, so that the cooling water in the condensing pipe two can be more in contact with heat to be fully heated.

[0011] Further, the outer side of the sleeve one is provided with an exhaust pipe one, the exhaust pipe one is provided with a plurality of air pipes one, the air pipes one penetrate through the sleeve one and are connected with the condensing pipe one, and the end of the exhaust pipe one is connected with the tail gas flash tank. The outer side of the sleeve two is provided with an exhaust pipe two, the exhaust pipe two is provided with a plurality of air pipes two, the air pipes two penetrate through the sleeve two and are connected with the condensing pipe two, and the end of the exhaust pipe two is connected with the furnace body flash tank. The exhaust pipe one connected with the tail gas flash tank and the exhaust pipe two connected with the furnace body flash tank can send the steam generated in the condensing pipe to the flash tank for use; the tail gas flash tank flashes 1.0MPa steam for use in the present workshop and other workshops; the furnace body flash tank flashes 0.4MPa steam for use in the present workshop and other workshops.

[0012] Further, the water outlet pipe two is connected to the tail gas flash tank, and the water outlet pipe three is connected to the furnace body flash tank. The heated cooling water is introduced into the flash tank, so that the flash tank can flash out steam of corresponding pressure faster, thereby saving energy consumption.

[0013] Further, the hydrogen preheater is connected with the mixer through the pipe one, and the mixer is connected to the reduction furnace through the pipe two. The hydrogen gas can be sent to the reduction furnace for use through the connection of the mixer and the reduction furnace. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a whole structure schematic view of the embodiment of the utility model.

[0015] Figure 2 It is the structure schematic view of sleeve mechanism one and sleeve mechanism two of the embodiment of the utility model.

[0016] Figure 3 It is the front view of sleeve mechanism one and sleeve mechanism two of the embodiment of the utility model.

[0017] Figure 4 It is the section view of sleeve mechanism one and sleeve mechanism two of the embodiment of the utility model.

[0018] The following is further explained in detail through specific embodiment:

[0019] The reference signs in the drawings of the specification include: reduction furnace 1, tail gas coil 2, water inlet pipe one 3, water outlet pipe one 4, jacket mechanism one 5, tail gas pipe 6, hydrogen preheater 7, pipe one 8, mixer 9, pipe two 10, heat conduction pipe one 11, sleeve one 12, connecting plate one 13, condensing pipe one 14, water inlet pipe two 15, water outlet pipe two 16, air pipe one 17, exhaust pipe one 18, connecting pipe 19, heat conduction pipe two 20, condensing pipe two 21, water inlet pipe three 22, water outlet pipe three 23, air pipe two 24, exhaust pipe two 25, sleeve two 26, connecting plate two 27, jacket mechanism two 28. DETAILED DESCRIPTION

[0020] The embodiment is basically as shown in the accompanying drawings. Figures 1-4The diagram shows a waste heat recovery device for the tail gas of a polycrystalline silicon reduction furnace. The device includes a reduction furnace 1, with a tail gas coil 2 connected to the tail gas outlet. The tail gas coil 2 is connected to an inlet pipe 3 and an outlet pipe 4. The outlet pipe 4 is connected to a base flash tank, which can flash-evaporate 0.2 MPa steam for use in other workshops. The other end of the tail gas coil 2 is connected to a jacket mechanism 5. The other end of the jacket mechanism 5 is connected to a second jacket mechanism 28 via a connecting pipe 19. The other end of the second jacket mechanism 28 is connected to a tail gas pipe 6. The other end of the tail gas pipe 6 is connected to a main tail gas pipe, which is connected to a hydrogen preheater 7. The hydrogen preheater 7 is connected to a mixer 9 via a conduit 8. The mixer 9 is connected to the reduction furnace 1 via a conduit 10. Through the connection between the mixer 9 and the reduction furnace 1, hydrogen can be delivered into the reduction furnace 1 for use.

[0021] like Figure 2 , Figure 3 , Figure 4 As shown, the jacket mechanism 5 includes a heat-conducting pipe 11, one end of which is connected to the exhaust coil 2 and the other end is fixed to the connecting pipe 19. A sleeve 12 is provided on the outside of the heat-conducting pipe 11, and the end of the sleeve 12 is fixed to the heat-conducting pipe 11 via a connecting plate 13. A spiral condenser pipe 14 is provided on the heat-conducting pipe 11, spirally wound around it. The two ends of the condenser pipe 14 are respectively connected to an inlet pipe 15 and an outlet pipe 16. The spiral condenser pipe 14 increases the contact between the condenser pipe 14 and the heat-conducting pipe 11, allowing the cooling water inside the condenser pipe 14 to be fully heated. The jacket mechanism 28 includes a heat-conducting pipe 20, one end of which is fixed to the connecting pipe 19 and the other end is connected to the exhaust pipe 6. Above, a sleeve 26 is provided on the outside of the heat conduction pipe 20. The end of the sleeve 26 is fixed to the heat conduction pipe 20 through a connecting plate 27. A spiral condenser pipe 21 is provided on the heat conduction pipe 20. The condenser pipe 21 is spirally wound on the heat conduction pipe 20. The two ends of the condenser pipe 21 are respectively connected to the inlet pipe 3 22 and the outlet pipe 3 23. Through the spiral condenser pipe 21, there is more contact surface between the condenser pipe 21 and the heat conduction pipe 20, so that the cooling water in the condenser pipe 21 can come into more contact with heat and be fully heated. The outlet pipe 2 16 is connected to the tail gas flash tank, and the outlet pipe 3 23 is connected to the furnace body flash tank. By passing the heated cooling water into the flash tank, the flash tank can flash out steam of the corresponding pressure more quickly, saving energy consumption.

[0022] like Figure 2 , Figure 3 , Figure 4As shown, an exhaust pipe 18 is provided on the outside of sleeve 12. Multiple vent pipes 17 are provided on exhaust pipe 18. Vent pipes 17 pass through sleeve 12 and connect to condenser pipe 14. The end of exhaust pipe 18 is connected to the tail gas flash tank. An exhaust pipe 25 is provided on the outside of sleeve 26. Multiple vent pipes 24 are provided on exhaust pipe 25. Vent pipes 24 pass through sleeve 26 and connect to condenser pipe 21. The end of exhaust pipe 25 is connected to the furnace body flash tank. By connecting exhaust pipe 18 to the tail gas flash tank and exhaust pipe 25 to the furnace body flash tank, the steam generated in the condenser pipe can be sent to the flash tank for utilization. Through the tail gas flash tank, 1.0 MPa steam is flashed out for use in this workshop and other workshops; through the furnace body flash tank, 0.4 MPa steam is flashed out for use in this workshop and other workshops.

[0023] The specific implementation process of this utility model is as follows: When in use, the exhaust gas of the reduction furnace 1 is discharged into the exhaust gas coil 2, so that the high temperature exhaust gas heats the cooling water at the outer tube of the exhaust gas coil 2 to obtain saturated steam. As the exhaust gas continues to flow, it will pass through the first jacket mechanism 5 and the second jacket mechanism 28, and heat the cooling water on the outer tube of the jacket mechanism to obtain saturated steam again. Finally, the exhaust gas flows into the hydrogen preheater 7.

[0024] This solution uses tail gas coil 2, jacket mechanism 1 5, and jacket mechanism 2 28 to flash-evaporate saturated steam at different pressures from cooling water for use in the workshop, thereby reducing workshop production costs. By introducing tail gas into hydrogen preheater 7, the hydrogen in it is preheated. The increase in hydrogen temperature reduces heat absorption after it enters the reduction furnace for reaction, thus reducing reaction power consumption.

[0025] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A device for utilizing waste heat from the tail gas of a polycrystalline silicon reduction furnace, comprising a reduction furnace, characterized in that: The tail gas outlet of the reduction furnace is connected to a tail gas coil. The other end of the tail gas coil is connected to a first jacket mechanism. The other end of the first jacket mechanism is connected to a second jacket mechanism via a connecting pipe. The other end of the second jacket mechanism is connected to the tail gas pipe. The other end of the tail gas pipe is connected to the tail gas main pipe. The tail gas main pipe is connected to the hydrogen preheater.

2. The waste heat recovery device for the tail gas of a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The exhaust coil is connected to an inlet pipe and an outlet pipe, with the outlet pipe connected to the flash tank on the chassis.

3. The waste heat recovery device for the tail gas of a polycrystalline silicon reduction furnace according to claim 2, characterized in that: The jacket mechanism includes a heat-conducting pipe, one end of which is connected to the exhaust coil and the other end is fixed to the connecting pipe. A sleeve is provided on the outside of the heat-conducting pipe, and the end of the sleeve is fixed to the heat-conducting pipe through a connecting plate. A spiral condenser is provided on the heat-conducting pipe, which is spirally wound around the heat-conducting pipe. A water inlet pipe and a water outlet pipe are respectively connected to both ends of the condenser.

4. The waste heat utilization device for the tail gas of a polycrystalline silicon reduction furnace according to claim 3, characterized in that: The jacket mechanism 2 includes a heat-conducting pipe 2, one end of which is fixed to a connecting pipe and the other end is connected to an exhaust pipe. A sleeve 2 is provided on the outside of the heat-conducting pipe 2, and the end of the sleeve 2 is fixed to the heat-conducting pipe 2 through a connecting plate 2. A spiral condenser 2 is provided on the heat-conducting pipe 2, and the condenser 2 is spirally wound on the heat-conducting pipe 2. The two ends of the condenser 2 are respectively connected to a water inlet pipe 3 and a water outlet pipe 3.

5. The waste heat utilization device for the tail gas of a polycrystalline silicon reduction furnace according to claim 4, characterized in that: The outer side of the first sleeve is provided with an exhaust pipe, and the exhaust pipe is provided with multiple vent pipes. The vent pipes pass through the first sleeve and are connected to the first condenser pipe. The end of the exhaust pipe is connected to the tail gas flash tank. The outer side of the second sleeve is provided with an exhaust pipe, and the exhaust pipe is provided with multiple vent pipes. The vent pipes pass through the second sleeve and are connected to the second condenser pipe. The end of the exhaust pipe is connected to the furnace body flash tank.

6. The waste heat recovery device for the tail gas of a polycrystalline silicon reduction furnace according to claim 5, characterized in that: The second water outlet pipe is connected to the exhaust gas flash tank, and the third water outlet pipe is connected to the furnace body flash tank.

7. The waste heat utilization device for the tail gas of a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The hydrogen preheater is connected to a mixer via conduit one, and the mixer is connected to the reduction furnace via conduit two.

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