High boiling purification cracking high efficiency feeding system

Abstract

The utility model provides a kind of high-boiling purification cleavage high-efficiency feeding system, comprising: for receiving and storing the high-boiling cache jar (1) of upstream system high-boiling material, its bottom outlet is connected with the bottom inlet of adsorption column (3) fluid, the top outlet of the adsorption column (3) is connected with the inlet of negative pressure enrichment tank (4) fluid, the top outlet of the negative pressure enrichment tank (4) is connected with the inlet of gas phase condenser (6) fluid, bottom outlet is connected with the bottom inlet of high-boiling cleavage kettle (5) fluid, the top outlet of the high-boiling cleavage kettle (5) is connected with the inlet of gas phase condenser (6) fluid, bottom outlet is connected with the inlet of hydrolysis soaking pool (2) fluid, the outlet of the hydrolysis soaking pool (2) is connected with the inlet of separator (8) fluid, the top outlet of the separator (8) is connected with the top inlet of distillation tank (9) fluid, the outlet of the gas phase condenser (6) is connected with the inlet of collection tank (7) fluid.

Description

Technical Field

[0001] This utility model relates to a feeding system, and more particularly to a high-boiling-point purification and pyrolysis high-efficiency feeding system. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] In the polysilicon production process, the slurry produced by the cold hydrogenation unit is mostly a high-boiling-point substance, mainly a solid-liquid mixture consisting of silicon tetrachloride, trichlorosilane, and catalysts. The current process involves treating it in a high-boiling-point pyrolysis reactor to improve the recovery rate of chlorosilanes, save water resources and alkaline lime water consumption in the downstream hydrolysis and neutralization system, further improve the quality of the slurry treatment process, and achieve the goal of recycling by-products.

[0004] However, existing high-boiling-point pyrolysis systems fail to fully utilize chlorosilanes and HCl in the high-boiling-point environment due to high extractant costs, difficulty in separating high-boiling-point components, and low pyrolysis efficiency. Furthermore, the high-boiling-point environment contains a large amount of impurities such as metallic aluminum, which can easily cause pipeline blockage and prevent material discharge. This results in instability in the overall system operation, and downstream hydrolysis wastes a large amount of water resources and alkaline lime water, leading to severe equipment wear and tear.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0006] Purpose of the invention: The technical problem to be solved by this utility model is to provide a high-boiling-point purification and pyrolysis high-efficiency feeding system to address the shortcomings of the existing technology.

[0007] To solve the above-mentioned technical problems, this utility model discloses a high-boiling-point purification and pyrolysis high-efficiency feeding system, comprising:

[0008] A high-boiling-point buffer tank is used to receive and store high-boiling-point materials from the upstream system. The bottom outlet of the high-boiling-point buffer tank is fluidly connected to the bottom inlet of the adsorption column. The top outlet of the adsorption column is fluidly connected to the inlet of the negative pressure concentration tank. The top outlet of the negative pressure concentration tank is fluidly connected to the inlet of the gas phase condenser. The bottom outlet of the high-boiling-point pyrolysis vessel is fluidly connected to the bottom inlet of the high-boiling-point pyrolysis vessel. The top outlet of the high-boiling-point pyrolysis vessel is fluidly connected to the inlet of the gas phase condenser. The bottom ... hydrolysis soaking tank. The outlet of the hydrolysis soaking tank is fluidly connected to the inlet of the separator. The top outlet of the separator is fluidly connected to the top inlet of the distillation tank. The outlet of the gas phase condenser is fluidly connected to the inlet of the collection tank.

[0009] Furthermore, the high-boiling-point buffer tank is equipped with an ethylene glycol jacket for cooling, which is used to flocculate the metallic impurities in the high-boiling-point material stored in the high-boiling-point buffer tank. The flocculated material is discharged from the bottom outlet of the high-boiling-point buffer tank.

[0010] Furthermore, a feed pump and a filter are provided between the bottom inlet of the adsorption column and the bottom outlet of the high-boiling buffer tank.

[0011] Furthermore, differential pressure gauges are provided at the top and bottom of the inner wall of the adsorption column, and a nitrogen purging pipeline is also provided at the bottom inlet of the adsorption column.

[0012] Furthermore, the top outlet of the negative pressure concentration tank is fluidly connected to the gas phase condenser via a vacuum pump;

[0013] The bottom outlet of the negative pressure concentration tank is fluidly connected to the high-boiling pyrolysis reactor via a high-boiling transfer pump.

[0014] The outer wall of the negative pressure concentration tank is equipped with a steam jacket for heating.

[0015] Furthermore, the high-boiling pyrolysis vessel is equipped with a stirrer inside and an extractant and hydrogen chloride gas inlet at the bottom;

[0016] The outer wall of the high-boiling pyrolysis vessel is equipped with a steam jacket for heating.

[0017] Furthermore, the gas-phase condenser uses ethylene glycol as a refrigerant to condense and produce liquid chlorosilane.

[0018] Furthermore, the liquid chlorosilane stored in the collection tank is discharged externally via a product delivery pump.

[0019] Furthermore, the hydrolysis soaking tank is connected to the separator via a high-boiling-point water delivery pump;

[0020] After solid-liquid separation, the separator discharges high-boiling water from the top into the distillation tank and discharges solid hydrolysate from the bottom.

[0021] Furthermore, the distillation tank has a steam jacket on its outer wall for heating, which distills the substances inside the tank. The water vapor produced is discharged from the bottom, and the aluminum trichloride product is discharged from the bottom.

[0022] Beneficial effects:

[0023] 1. This system achieves the separation of light components in high-boiling states, the purification and cracking of heavy components, and the separation and distillation of the hydrolyzed water, thus achieving efficient feeding and reducing the consumption of extractant.

[0024] 2. In this system, high-boiling water enters a centrifuge to separate the solid hydrolysate from the high-boiling water. The separated high-boiling water then enters a distillation unit, reducing wastewater discharge, reducing the amount of downstream alkali solution used, and obtaining aluminum trichloride product that can be used as an industrial water purification agent.

[0025] 3. In this system, the use of a negative pressure concentration unit breaks the boiling point of the material, which can more efficiently separate the light components in the high-boiling material, increase the concentration of high-boiling material, reduce the problem of large amount of extractant used in downstream cracking units due to light components, reduce production costs, improve the overall system's feed stability and efficiency, and enhance the market competitiveness of the product. Attached Figure Description

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0027] Figure 1 This is a schematic diagram of the overall architecture of this system.

[0028] In the diagram, 1 is a high-boiling-point buffer tank, 11 is a feed pump, 12 is a filter, 3 is an adsorption column, 31 is a nitrogen purging line, 32 is a differential pressure gauge, 4 is a concentration tank, 41 is a vacuum pump, 42 is a high-boiling-point transfer pump, 5 is a high-boiling-point pyrolysis vessel, 51 is a stirrer, 6 is a vapor phase condenser, 7 is a collection tank, 71 is a product transfer pump, 2 is a hydrolysis soaking tank, 21 is a high-boiling-point water transfer pump, 8 is a centrifugal separator, and 9 is a distillation tank. Detailed Implementation

[0029] The overall concept of this invention is as follows: In the prior art, high-boiling materials from the upstream production process of polysilicon enter a high-boiling buffer tank. This process fails to fully utilize the chlorosilanes and HCl in the high-boiling material due to high extractant costs, difficulty in separating high-boiling materials, and low pyrolysis efficiency. Furthermore, the high-boiling material contains a large amount of impurities such as metallic aluminum, which easily causes pipeline blockage and prevents material discharge, resulting in instability in the overall system operation and severe equipment corrosion and wear. The main principle of this invention is to add an ethylene glycol jacket to the outer wall of the high-boiling buffer tank to lower the material temperature, causing the metallic impurities in the high-boiling material to flocculate. The flocculated high-boiling material is then transported to a fixed adsorption column via a feed pump. A solid adsorbent is added to the adsorption column to remove the impurities from the high-boiling material. Metal impurities are adsorbed, and a nitrogen purging line is added to the adsorption column to prevent obstruction of material flow. Nitrogen is used for purging. After passing through the adsorption column, the high-boiling material enters the negative pressure concentration tank. A reciprocating vacuum pump draws the concentration tank to negative pressure. The negative pressure distillation effect is used to better separate chlorosilanes and polysilanes in the high-boiling material, achieving efficient recovery of light components. A bottom pump is added to the bottom of the negative pressure concentration tank, and the concentrated high-boiling material is transported to the high-boiling pyrolysis reactor through a high-boiling transfer pump. A new type of extractant is added to the high-boiling pyrolysis reactor, and HCl gas is introduced to pyrolyze the concentrated high-boiling material. This achieves stable and efficient pyrolysis of high-boiling material, reduces equipment corrosion and wear, improves the stability and efficiency of the overall feeding system, and saves company costs.

[0030] This invention proposes a high-boiling-point pyrolysis system that separates materials by sedimentation and controls the feed temperature, such as... Figure 1 As shown, the specific technical solution is as follows:

[0031] High-boiling-point material input from the upstream cold hydrogenation unit is discharged to the high-boiling-point buffer tank 1 of this unit. The high-boiling-point buffer tank 1 has an ethylene glycol jacket (not shown in the figure) installed on its side wall to flocculate metallic impurities such as aluminum trichloride in the high-boiling-point material. The flocculated high-boiling-point material is then conveyed to the fixed adsorption column 3 via the feed pump 11. A solid adsorbent is added to the adsorption column 3 to adsorb metallic impurities, metal chlorides, and metal ions in the high-boiling-point material. A nitrogen purging line 31 is also installed inside the adsorption column 3. Nitrogen is used for purging when the feed or discharge is obstructed. After passing through the adsorption column, the high-boiling-point material enters the concentration tank 4, which is a negative pressure storage tank. Its purpose is: 1. To better transport the material in the adsorption column 3 to the negative pressure tank via vacuum. Concentration tank 42 is evacuated to negative pressure by vacuum pump 41. Negative pressure distillation is used to better separate the light chlorosilane components from polysilanes in the high-boiling state, achieving efficient recovery of the light components. A steam jacket (not shown in the figure) is added to the outside of the negative pressure concentration tank 4 as a heat source for distillation. After concentration, the chlorosilane content is reduced to below 3%. A high-boiling transfer pump 42 is added to the bottom of the negative pressure concentration tank 4. The concentrated high-boiling state is transferred to the high-boiling pyrolysis reactor 5 by the high-boiling transfer pump 42. A new type of extractant is added to the high-boiling pyrolysis reactor 5, and HCl gas is introduced to pyrolyze the concentrated high-boiling state, thereby achieving stable and efficient pyrolysis efficiency and improving the stability and efficiency of the overall feeding system.

[0032] Example:

[0033] In one embodiment, the automatic feeding system proposed in this invention is mainly used for the separation, adsorption, pyrolysis and recovery of high-boiling mixtures of chlorosilanes after cold hydrogenation.

[0034] This automatic feeding system includes: a high-boiling-point buffer tank 1, a feed pump 11, an adsorption column 3, a negative pressure concentration tank 4, a reciprocating vacuum pump 41, a high-boiling-point transfer pump 42, a high-boiling-point pyrolysis reactor 5, a high-boiling-point pyrolysis reactor agitator 51, a vapor phase condenser 6, a collection tank, a product transfer pump, level gauges L1 and L2, a differential pressure gauge P1, a hydrolysis soaking tank, a high-boiling-point water transfer pump, a centrifuge, and a distillation tank.

[0035] When the system is working: the high-boiling-point substance is discharged from the external cold hydrogenation device to the high-boiling-point buffer tank 1. A radar level gauge (not shown in the figure) is installed in the high-boiling-point buffer tank 1 to monitor the liquid level of the high-boiling-point buffer tank 1, and a differential pressure level gauge (not shown in the figure) is installed to measure the pressure difference between the bottom and the top of the high-boiling-point buffer tank 1.

[0036] The high-boiling-point buffer tank 1 is equipped with a shut-off valve (not shown in the figure) to cut off the high-boiling-point feed in case of shutdown or system failure.

[0037] The high-boiling material in the high-boiling buffer tank 1 is cooled and flocculated by ethylene glycol in the main body jacket and then transported to the adsorption column 3 by the feed pump 11. The adsorption column 3 is filled with adsorbent (e.g., diatomaceous earth). The high-boiling material passes through the adsorption column 3 from bottom to top. Differential pressure gauges 32 are set at the bottom and top of the adsorption column 3. When the differential pressure is too high and the material cannot be discharged, the bottom nitrogen auxiliary blowing pipeline 31 is opened to assist blowing.

[0038] After passing through the adsorption column 3, the high-boiling material enters the negative pressure concentration tank 4. A steam jacket (not shown in the figure) is added to the outer wall of the negative pressure concentration tank 4 for heating. During operation, steam is introduced into the jacket of the negative pressure concentration tank 4, and the gaseous material at the top is drawn to the gas phase condenser 6 by the vacuum pump 41 (dry type, reciprocating type, etc.). The light components after condensation, mainly including STC trichlorosilane and TCS silicon tetrachloride, enter the collection tank 7. The collected material is sent to the upstream cold hydrogenation unit for reuse.

[0039] The heavy components at the bottom of the negative pressure concentration tank 4, mainly including polysilane and siloxane, are transported to the bottom of the high-boiling pyrolysis vessel 5 via the bottom high-boiling transfer pump 42. A steam jacket is added to the outer wall of the high-boiling pyrolysis vessel 5 for heating (not shown in the figure), and an agitator 51 is added inside to better separate the liquid into layers, change turbulent flow into laminar flow, and increase the contact area between the material and the extractant and HCl gas.

[0040] Agitator 51, which can be a paddle agitator, has a simple structure consisting of straight blades and is suitable for low-viscosity fluids. It mainly generates radial flow with relatively low mixing intensity. Laminar flow is formed when the Reynolds number is <2000.

[0041] After the material at the bottom of the negative pressure concentration tank 4 is transported to the high-boiling pyrolysis reactor 5, a catalyst and HCl gas are introduced into the high-boiling pyrolysis reactor 5. Under the action of jacket steam heating, the gaseous material at the top of the reactor 5 enters the gas phase condenser 6. The liquid chlorosilane after being condensed by the gas phase condenser 6 enters the collection tank 7 and is transported to the upstream cold hydrogenation unit for recycling via the product transfer pump 71.

[0042] The heavy component material at the bottom of the reactor 5, mainly composed of metal ions such as aluminum trichloride, is discharged to the hydrolysis soaking tank 2 by pressure difference to hydrolyze and neutralize the residual trace amounts of chlorosilane. The neutralized water is then transported to the centrifugal separator 8 via the high-boiling water transfer pump 21 to separate the hydrolysate from the water. The high-boiling water after separation contains aluminum trichloride as the main component. The high-boiling water after separation enters the distillation tank 9 and is heated by the steam jacket on the outer wall of the distillation tank (not shown in the figure) to purify the high-boiling water. The purified aluminum trichloride can be used as an industrial water purification agent.

[0043] This system effectively increases the concentration of high-boiling water, reduces the amount of extractant used, purifies high-boiling water, reduces the amount of wastewater and downstream alkali solution used, and the distilled high-boiling water yields aluminum trichloride, which can be used as an industrial water purification agent, achieving efficient recovery, reducing costs, and improving the overall efficiency of the feeding system.

[0044] This invention provides a concept and method for a high-boiling-point purification and pyrolysis high-efficiency feed system. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technology.

Claims

1. A high-boiling-point purification and pyrolysis high-efficiency feed system, characterized in that, include: A high-boiling buffer tank (1) is used to receive and store high-boiling materials from the upstream system. The bottom outlet of the high-boiling buffer tank (1) is fluidly connected to the bottom inlet of the adsorption column (3). The top outlet of the adsorption column (3) is fluidly connected to the inlet of the negative pressure concentration tank (4). The top outlet of the negative pressure concentration tank (4) is fluidly connected to the inlet of the gas phase condenser (6). The bottom outlet is fluidly connected to the bottom inlet of the high-boiling pyrolysis vessel (5). The top outlet of the high-boiling pyrolysis vessel (5) is fluidly connected to the inlet of the gas phase condenser (6). The bottom outlet is fluidly connected to the inlet of the hydrolysis soaking tank (2). The outlet of the hydrolysis soaking tank (2) is fluidly connected to the inlet of the separator (8). The top outlet of the separator (8) is fluidly connected to the top inlet of the distillation tank (9). The outlet of the gas phase condenser (6) is fluidly connected to the inlet of the collection tank (7).

2. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 1, characterized in that, The high-boiling buffer tank (1) is equipped with an ethylene glycol jacket for cooling, which is used to flocculate the metal impurities in the high-boiling material stored in the high-boiling buffer tank (1). The flocculated material is discharged from the bottom outlet of the high-boiling buffer tank (1).

3. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 2, characterized in that, A feed pump (11) and a filter (12) are provided between the bottom inlet of the adsorption column (3) and the bottom outlet of the high boiling buffer tank (1).

4. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 3, characterized in that, The top and bottom of the inner wall of the adsorption column (3) are provided with differential pressure gauges (32), and the bottom inlet of the adsorption column (3) is also provided with a nitrogen purging pipeline (31).

5. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 4, characterized in that, The top outlet of the negative pressure concentration tank (4) is fluidly connected to the gas phase condenser (6) via a vacuum pump (41); The bottom outlet of the negative pressure concentration tank (4) is fluidly connected to the high-boiling pyrolysis vessel (5) via a high-boiling transfer pump (42); The outer wall of the negative pressure concentration tank (4) is provided with a steam jacket for heating.

6. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 5, characterized in that, The high-boiling pyrolysis vessel (5) is equipped with a stirrer (51) inside the vessel and an extractant and hydrogen chloride gas inlet at the bottom; The high-boiling pyrolysis vessel (5) has a steam jacket for heating on its outer wall.

7. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 6, characterized in that, The gas phase condenser (6) uses ethylene glycol as a refrigerant to condense and produce liquid chlorosilane.

8. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 7, characterized in that, The liquid chlorosilane stored in the collection tank (7) is output to the outside through the product delivery pump (71).

9. The high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 8, characterized in that, The hydrolysis soaking tank (2) is connected to the separator (8) via a high boiling water delivery pump (21); After the separator (8) performs solid-liquid separation, the high-boiling water is discharged from the top to the distillation tank (9), and the solid hydrolysate is discharged from the bottom.

10. A high-boiling-point purification and pyrolysis high-efficiency feed system according to claim 9, characterized in that, The distillation tank (9) has a steam jacket on its outer wall for heating, which distills the substances inside the tank. The water vapor produced is discharged from the bottom, and the aluminum trichloride product is discharged from the bottom.

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