A method and system for treating polysilicon slurry

Abstract

The application provides a polysilicon residue slurry treatment method and system. The polysilicon residue slurry treatment method comprises the following steps: performing hydrolysis treatment on dry powder in a residue slurry treatment process to obtain a first gas phase and a first liquid phase; performing washing treatment on the first gas phase by using water to obtain a second gas phase and a second liquid phase; wherein lime milk is added in the hydrolysis treatment, and the lime milk is added in the washing treatment; the second gas phase is discharged into air, and the first liquid phase and the second liquid phase are subjected to wastewater treatment. The treatment method can efficiently and environmentally protectively treat the dry powder in the polysilicon residue slurry, and has high environmental friendliness.

Description

Technical Field

[0001] This invention relates to a method and system for treating polycrystalline silicon slag slurry, belonging to the field of chemical separation technology. Background Technology

[0002] With increasing demand, the photovoltaic and integrated circuit industries have experienced rapid development. Polysilicon is a core raw material for both industries, leading to a surge in polysilicon production by various companies.

[0003] Currently, almost all polysilicon manufacturers use the modified Siemens process, which generates a large amount of slurry during polysilicon production. For example, a certain amount of slurry is produced in the chlorination and hydrochlorination section of polysilicon production. The slurry mainly includes chlorosilanes, silicon powder, and metal chlorides (e.g., AlCl3). The treatment and utilization of this slurry is a challenge that the polysilicon industry must face. Summary of the Invention

[0004] This invention provides a method for treating polycrystalline silicon slag slurry, which can efficiently and environmentally treat the dry powder in the polycrystalline silicon slag slurry and has high environmental friendliness.

[0005] This invention provides a polycrystalline silicon slag slurry treatment system for the recycling method described in the embodiments. The system has a simple structure and is suitable for widespread application.

[0006] This invention provides a method for treating polycrystalline silicon slag slurry, comprising the following steps:

[0007] The dry powder from the slurry treatment process is hydrolyzed to obtain a first gas phase and a first liquid phase;

[0008] The first gas phase is washed with water to obtain a second gas phase and a second liquid phase.

[0009] Lime milk is added in both the hydrolysis and washing processes.

[0010] The second gas phase is discharged into the air, and the first liquid phase and the second liquid phase are used for wastewater treatment.

[0011] In the treatment method described above, the hydrolysis treatment is a continuous process, and the temperature during the hydrolysis treatment is 40–85°C, and the pressure is 0.002–0.05 MPaG; or,

[0012] The hydrolysis treatment is an intermittent process, wherein the temperature is 40–85°C, the time is 0.2–2 h, and the pressure is 0.002–0.05 MPaG.

[0013] In the above-described treatment method, the washing process is continuous, and the temperature during the washing process is 40–85°C, and the spray volume is 5–40 m³ / h. 3 / h; or,

[0014] The washing process is intermittent, with a temperature of 40–85°C and a spray rate of 5–40 m³ / h. 3 / h, with a time range of 0.2 to 2h.

[0015] The processing method described above further includes condensing the first liquid phase to obtain a third liquid phase, and using the third liquid phase to perform the hydrolysis treatment.

[0016] In the processing method described above, the temperature of the third liquid phase is 35–60°C.

[0017] The present invention provides a processing system for implementing the polycrystalline silicon slag slurry processing method described above, comprising: a dry powder hydrolysis reactor and a tail gas scrubbing tower;

[0018] The gas phase outlet of the dry powder hydrolysis reactor is connected to the gas phase inlet of the tail gas scrubbing tower.

[0019] The processing system described above, wherein the dry powder hydrolysis reactor includes a reactor body and an empty tower located on top of the reactor body and communicating with the reactor body;

[0020] The gas phase outlet is located at the top of the empty tower, and the empty tower has a liquid phase inlet;

[0021] The vessel is used for hydrolysis treatment.

[0022] The processing system described above, wherein a nitrogen inlet is also provided at the top of the empty tower; and / or,

[0023] The empty tower also has a lime milk inlet.

[0024] The processing system described above further includes: a dry powder hydrolysate condenser;

[0025] The outlet of the reactor body is connected to the inlet of the dry powder hydrolysate condenser, and the outlet of the dry powder hydrolysate condenser is connected to the empty tower.

[0026] The processing system described above further includes: an exhaust gas tower pump;

[0027] The bottom of the tail gas scrubbing tower is connected to the inlet of the tail gas tower pump, and the outlet of the tail gas tower pump is connected to the top of the tail gas scrubbing tower.

[0028] This invention provides a method for treating polycrystalline silicon slag slurry, which involves sequentially hydrolyzing and washing the dry powder during the slag slurry treatment process. This method achieves efficient and environmentally friendly treatment of the dry powder and has excellent environmental friendliness.

[0029] This invention provides a polycrystalline silicon slag slurry treatment system for implementing the above-mentioned recycling method. The system has a simple structure and is suitable for widespread application. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments of the present invention or related technologies are briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the hydrolysis process in some embodiments of the present invention;

[0032] Figure 2 This is a schematic diagram of the washing process in some embodiments of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 2: Dry powder hydrolysate pump;

[0035] 3: Dry powder hydrolysate condenser;

[0036] 4: Exhaust gas scrubbing tower;

[0037] 5: Exhaust gas tower pump;

[0038] 11: The vessel body;

[0039] 12: Empty Tower. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Figure 1 This is a schematic diagram of the hydrolysis process in some embodiments of the present invention; Figure 2 This is a schematic diagram of the washing process in some embodiments of the present invention. For example... Figure 1 and Figure 2As shown, the first aspect of the present invention provides a method for treating polycrystalline silicon slag slurry, comprising the following steps:

[0042] The dry powder from the slurry treatment process is hydrolyzed to obtain a first gas phase and a first liquid phase;

[0043] The first gas phase is washed with water to obtain the second gas phase and the second liquid phase.

[0044] Lime milk is added during both the hydrolysis and washing processes.

[0045] The second gas phase is discharged into the air, while the first and second liquid phases are used for wastewater treatment.

[0046] This invention does not specifically limit the dry powder; the dry powder can be any dried powder from which the slurry has been removed during the slurry treatment process. The dry powder mainly includes silicon powder and a small amount of chlorosilane.

[0047] The processing method of the present invention specifically includes: hydrolyzing the dry powder in the slurry treatment process under the action of lime milk, the lime milk reacts with the dry powder to generate a first gas phase including hydrogen and hydrogen chloride and a first liquid phase including calcium chloride, calcium silicate and silicon dioxide; then washing the first gas phase with water under the action of lime milk, the lime milk reacts with hydrogen chloride to obtain a second gas phase including hydrogen and a second liquid phase including calcium chloride, wherein the second gas phase can be discharged into the air, and the first liquid phase and the second liquid phase can be used for wastewater treatment.

[0048] In some embodiments, lime slurry can be lime slurry with a mass percentage of 80%.

[0049] This invention efficiently removes waste from the dry powder during the polycrystalline silicon slag slurry treatment process by sequentially hydrolyzing and washing it. This treatment method has excellent environmental friendliness and is suitable for widespread application.

[0050] In this invention, the specific parameters for hydrolysis and washing treatments can be selected to further improve the processing efficiency of the treatment method.

[0051] In this invention, the hydrolysis treatment can be either continuous or intermittent. When the hydrolysis treatment is continuous, the temperature is 40–85°C and the pressure is 0.002–0.05 MPaG.

[0052] When the hydrolysis treatment is performed in an intermittent manner, the temperature is 40–85℃, the time is 0.2–2h, and the pressure is 0.002–0.05MPaG.

[0053] For example, in the hydrolysis process, the temperature can be any one of 40°C, 50°C, 60°C, 70°C, 80°C, 85°C, or a combination of any two of them;

[0054] The pressure can be any one of 0.002 MPa, 0.003 MPa, 0.01 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa, or a range of any two of these.

[0055] When the hydrolysis treatment is a batch treatment, the time can be any one of 0.2h, 0.3h, 0.5h, 1h, 2h, or any combination of two.

[0056] When the parameters of the hydrolysis treatment meet the above range, the lime milk and dry powder can react fully to generate a first gas phase including hydrogen and hydrogen chloride and a first liquid phase including calcium chloride, calcium silicate and silica, while saving energy consumption. This promotes the subsequent washing process and thus achieves more efficient processing of the dry powder.

[0057] In this invention, the washing process can be continuous or intermittent. When the washing process is continuous, the temperature is 40–85°C and the spray volume is 5–40 m³ / h. 3 / h;

[0058] When the washing process is intermittent, the temperature is 40–85℃ and the spray rate is 5–40 m³ / h. 3 / h, with a time range of 0.2 to 2h.

[0059] For example, in the washing process, the temperature can be any one of 40°C, 50°C, 60°C, 70°C, 80°C, 85°C, or any combination thereof;

[0060] The spray volume can be 5m 3 / h、7m 3 / h, 10m 3 / h, 20m 3 / h, 30m 3 / h, 40m 3 Any one of / h and the range consisting of any two of them;

[0061] When the washing process is intermittent, the time can be any one of 0.2h, 0.3h, 0.5h, 1h, 1.5h, 2h, or any combination thereof.

[0062] When the washing parameters meet the above range, the first gas phase can be washed more thoroughly while saving energy. Furthermore, the lime milk reacts with hydrogen chloride to obtain a second gas phase containing hydrogen and a second liquid phase containing calcium chloride, thereby achieving more efficient processing of dry powder.

[0063] In some embodiments of the present invention, the processing method further includes condensing the first liquid phase to obtain a third liquid phase, and using the third liquid phase for hydrolysis.

[0064] Specifically, the first liquid phase is condensed to obtain a third liquid phase that matches the temperature of the hydrolysis treatment. Then, the third liquid phase is used to hydrolyze the dry powder to obtain the first gas phase and the first liquid phase.

[0065] This invention involves condensing the first liquid phase to obtain a third liquid phase, which is then used for hydrolysis. The condensation process reduces heat generation during hydrolysis, preventing overheating and reducing the need for excessive water for cooling, thus conserving water. Furthermore, it allows for the recycling of water resources while further removing waste from the first liquid phase, improving processing efficiency.

[0066] Furthermore, the temperature of the third liquid phase is 35–60°C.

[0067] For example, the temperature of the third liquid phase can be any of 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, or a combination of any two of these.

[0068] When the temperature of the third liquid phase meets the above range, the third liquid phase can more efficiently hydrolyze the dry powder while saving energy, thus obtaining the first gas phase and the first liquid phase.

[0069] A second aspect of the present invention provides a processing system for implementing the polycrystalline silicon slag slurry processing method of the first aspect, comprising: a dry powder hydrolysis kettle and a tail gas scrubbing tower 4;

[0070] The gas phase outlet of the dry powder hydrolysis reactor is connected to the gas phase inlet of the tail gas scrubbing tower 4.

[0071] Specifically, the dry powder is hydrolyzed in a dry powder hydrolysis reactor to obtain a first gas phase and a first liquid phase. The first gas phase is output through the gas phase outlet of the dry powder hydrolysis reactor and enters the tail gas scrubbing tower 4 through the gas phase inlet. It is scrubbed in the tail gas scrubbing tower 4 to obtain a second gas phase and a second liquid phase. The second gas phase is discharged into the air, and the first liquid phase and the second liquid phase are used for wastewater treatment.

[0072] The polycrystalline silicon slag slurry treatment system of the present invention is used to implement the above-mentioned polycrystalline silicon slag slurry treatment method. The system can efficiently and environmentally treat the dry powder in the polycrystalline silicon slag slurry. It has a simple structure and is suitable for widespread application.

[0073] In some embodiments of the present invention, the dry powder hydrolysis reactor includes a reactor body 11 and an empty tower 12 located on top of the reactor body 11 and communicating with the reactor body 11.

[0074] The gas phase outlet is located at the top of the empty tower 12, and the empty tower 12 has a liquid phase inlet;

[0075] The vessel body 11 is used for hydrolysis treatment.

[0076] Specifically, the dry powder hydrolysis reactor includes a reactor body 11 and an empty tower 12 from top to bottom. The water required for the hydrolysis treatment enters the empty tower 12 through the liquid phase inlet of the empty tower, and then enters the reactor body 11 through the empty tower 12. The dry powder is hydrolyzed in the reactor body 11, and the first gas phase generated by the hydrolysis treatment is output through the gas phase outlet at the top of the empty tower 12.

[0077] In some embodiments, the empty tower 12 also has nozzles. Water enters the empty tower 12 through a liquid phase inlet and can be sprayed into the vessel body 11 through the nozzles. Furthermore, a distribution plate is provided below the nozzles to enhance the spraying effect. In some embodiments, the distribution plate can be located 500-1000 mm below the nozzles.

[0078] The present invention improves the efficiency of hydrolysis by allowing water to enter the reactor body 11 through the empty tower 12 for hydrolysis treatment, thereby further improving the processing efficiency of dry powder.

[0079] In some embodiments of the invention, a nitrogen inlet is also provided at the top of the air tower 12.

[0080] Specifically, nitrogen enters the empty tower 12 through the nitrogen inlet at the top of the empty tower 12, which can maintain the nitrogen environment at the top of the empty tower 12 and prevent air from returning to the empty tower 12.

[0081] In some embodiments of the present invention, the empty tower 12 also has a lime slurry inlet.

[0082] The lime slurry enters the empty tower 12 through the lime slurry inlet, and then enters the reactor 11 for hydrolysis. In some embodiments, the lime slurry inlet is located above the liquid phase inlet.

[0083] By allowing the lime slurry to enter the reactor body 11 through the empty tower 12, the dispersion of the lime slurry can be promoted, thereby improving the effect of hydrolysis treatment.

[0084] In some embodiments of the present invention, the processing system further includes: a dry powder hydrolysate condenser 3;

[0085] The outlet of the reactor body 11 is connected to the inlet of the dry powder hydrolysate condenser 3, and the outlet of the dry powder hydrolysate condenser 3 is connected to the empty tower 12.

[0086] Specifically, the first liquid phase generated by the hydrolysis treatment is output from the outlet of the reactor body 11, enters the dry powder hydrolysate condenser 3 through the inlet of the dry powder hydrolysate condenser 3, and is condensed in the dry powder hydrolysate condenser 3 to obtain the third liquid phase. The third liquid phase is output from the outlet of the dry powder hydrolysate condenser 3 and enters the empty tower 12, and then enters the reactor body 11 to participate in the hydrolysis treatment.

[0087] In some embodiments, a dry powder hydrolysate pump 2 is also included. The first liquid phase is pumped out from the bottom of the dry powder hydrolysis vessel by the dry powder hydrolysate pump 2 and enters the dry powder hydrolysate pump 2. After being output by the dry powder hydrolysate pump 2, it enters the dry powder hydrolysis condenser and is condensed by the dry powder hydrolysis condenser to form the third liquid phase.

[0088] In some embodiments of the present invention, the processing system further includes: tail gas tower pump 5;

[0089] The bottom of the exhaust gas scrubbing tower 4 is connected to the inlet of the exhaust gas tower pump 5, and the outlet of the exhaust gas tower pump 5 is connected to the top of the exhaust gas scrubbing tower 4.

[0090] Specifically, the second liquid phase is output from the bottom of the tail gas scrubbing tower 4, enters the tail gas tower pump 5 through the inlet of the tail gas tower pump 5, is output from the outlet of the tail gas tower pump 5, and enters the tail gas scrubbing tower 4 through the top of the tail gas scrubbing tower 4 for scrubbing treatment.

[0091] This invention uses a second liquid phase to participate in the washing process again, which can further remove waste from the second liquid phase, and can also save water and improve resource utilization.

[0092] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0093] Example 1

[0094] like Figure 1 and Figure 2 As shown, the polycrystalline silicon slag slurry treatment system of this embodiment includes: a dry powder hydrolysis kettle, a dry powder hydrolysate pump 2, a dry powder hydrolysate condenser 3, a tail gas scrubbing tower 4, and a tail gas tower pump 5.

[0095] The dry powder hydrolysis reactor includes a reactor body 11 and an empty tower 12 located at the top of the reactor body 11 and connected to the reactor body 11; the gas phase outlet is located at the top of the empty tower 12, the empty tower 12 has a liquid phase inlet and a lime slurry inlet, the top of the empty tower 12 also has a nitrogen inlet, the empty tower 12 also has a nozzle, and a distribution plate is located below the nozzle at a position 600 mm below the nozzle.

[0096] The vessel body 11 is used for hydrolysis treatment. The outlet of the vessel body 11 is connected to the inlet of the dry powder hydrolysate pump 2. The outlet of the dry powder hydrolysate pump 2 is connected to the inlet of the dry powder hydrolysate condenser 3. The outlet of the dry powder hydrolysate condenser 3 is connected to the empty tower 12.

[0097] The gas phase outlet of the dry powder hydrolysis kettle is connected to the gas phase inlet of the scrubbing tower, the bottom of the tail gas scrubbing tower 4 is connected to the inlet of the tail gas tower pump 5, and the outlet of the tail gas tower pump 5 is connected to the top of the tail gas scrubbing tower 4.

[0098] Example 2

[0099] The polycrystalline silicon slag slurry treatment method of this embodiment uses the treatment system of Embodiment 1, and specifically includes:

[0100] Water is introduced into the empty tower 12 through the liquid phase inlet, and lime slurry is introduced into the empty tower 12 through the lime slurry inlet. Water and lime slurry are introduced into the reactor body 11 through the empty tower 12. The dry powder is hydrolyzed in the reactor body 11 to obtain the first liquid phase and the first gas phase.

[0101] The first liquid phase is output from the outlet of the column body 11, enters the dry powder hydrolysate pump 2 through the inlet of the dry powder hydrolysate pump 2, is output from the outlet of the dry powder hydrolysate pump 2, and enters the dry powder hydrolysate condenser 3 through the inlet of the dry powder hydrolysate condenser 3 for condensation treatment to obtain the third liquid phase. The third liquid phase is output from the outlet of the dry powder hydrolysate condenser 3 and enters the empty column 12. The first liquid phase is output from the outlet pipeline of the dry powder hydrolysate pump 2 for wastewater treatment.

[0102] Nitrogen gas enters the empty tower 12 through the nitrogen inlet. The first gas phase is output through the gas phase outlet at the top of the empty tower 12 and enters the tail gas scrubbing tower 4 through the gas phase inlet. Under the action of lime slurry, it is scrubbed to obtain the second liquid phase and the second gas phase. The second liquid phase is output through the bottom of the tail gas scrubbing tower 4, enters the tail gas tower pump 5 through the inlet, is output through the outlet of the tail gas tower pump 5, and enters the tail gas scrubbing tower 4 through the top of the tail gas scrubbing tower 4. Part of the second liquid phase is output through the pipeline of the tail gas tower pump 5 for wastewater treatment. The second gas phase is discharged into the air through the top of the tail gas scrubbing tower 4.

[0103] In the hydrolysis treatment, the temperature was 55℃, the time was 0.5h, and the pressure was 0.006MPaG.

[0104] During the washing process, the temperature is 55℃ and the spray volume is 20m³. 3 / h, the time is 0.5h;

[0105] The temperature of the third liquid phase is 50℃.

[0106] Example 3

[0107] The method for treating polycrystalline silicon slag slurry in this embodiment is basically the same as that in Embodiment 2, except that:

[0108] Water is introduced into the empty tower 12 through the liquid phase inlet, and lime slurry is introduced into the empty tower 12 through the lime slurry inlet. Water and lime slurry are introduced into the reactor body 11 through the empty tower 12. The dry powder is hydrolyzed in the reactor body 11 to obtain the first liquid phase and the first gas phase.

[0109] The first liquid phase is output from the outlet of the reboiler of the vessel 11, enters the dry powder hydrolysate pump 2 through the inlet of the dry powder hydrolysate pump 2, and is output from the outlet of the dry powder hydrolysate pump 2 into the empty tower 12. The first liquid phase is output from the outlet pipeline of the dry powder hydrolysate pump 2 for wastewater treatment.

[0110] Nitrogen gas enters the empty tower 12 through the nitrogen inlet. The first gas phase is output through the gas phase outlet at the top of the empty tower 12 and enters the tail gas scrubbing tower 4 through the gas phase inlet. Under the action of lime slurry, it is scrubbed to obtain the second liquid phase and the second gas phase. The second liquid phase is output through the bottom of the tail gas scrubbing tower 4, enters the tail gas tower pump 5 through the inlet, is output through the outlet of the tail gas tower pump 5, and enters the tail gas scrubbing tower 4 through the top of the tail gas scrubbing tower 4. Part of the second liquid phase is output through the pipeline of the tail gas tower pump 5 for wastewater treatment. The second gas phase is discharged into the air through the top of the tail gas scrubbing tower 4.

[0111] In the hydrolysis treatment, the temperature was 55℃, the time was 0.5h, and the pressure was 0.006MPaG.

[0112] During the washing process, the temperature was 55℃, the spray rate was 20m³ / h, and the time was 0.5h.

[0113] Compared to Example 3, Example 2 incorporates a dry powder hydrolysate condenser 3 during the hydrolysis process. This avoids overheating during hydrolysis and saves water, reducing water consumption by 10m³ per 100kg of slurry. 3 This reduces water consumption and saves production costs.

[0114] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for treating polycrystalline silicon slag slurry, characterized in that, Includes the following steps: The dry powder from the slurry treatment process is hydrolyzed to obtain a first gas phase and a first liquid phase, wherein the dry powder includes silicon powder and a small amount of chlorosilane; The first gas phase is washed with water to obtain a second gas phase and a second liquid phase. Lime milk is added in both the hydrolysis and washing processes, and the mass percentage of the lime milk is 80%. The second gas phase is discharged into the air, and the first liquid phase and the second liquid phase are used for wastewater treatment.

2. The processing method according to claim 1, characterized in that, The hydrolysis treatment is a continuous process, wherein the temperature is 40~85℃ and the pressure is 0.002~0.05MPaG; or, The hydrolysis treatment is an intermittent process, wherein the temperature is 40~85℃, the time is 0.2~2h, and the pressure is 0.002~0.05MPaG.

3. The processing method according to claim 1 or 2, characterized in that, The washing process is a continuous process, and the temperature is 40~85℃, with a spray volume of 5~40m³. 3 / h; or, The washing process is intermittent, with a temperature of 40-85℃ and a spray rate of 5-40m³. 3 / h, with a time range of 0.2~2h.

4. The processing method according to claim 1 or 2, characterized in that, It also includes condensing the first liquid phase to obtain a third liquid phase, and using the third liquid phase to perform the hydrolysis treatment.

5. The processing method according to claim 4, characterized in that, The temperature of the third liquid phase is 35~60℃.

6. A processing system for implementing the polycrystalline silicon slag slurry processing method according to any one of claims 1-5, characterized in that, include: Dry powder hydrolysis reactor and tail gas scrubbing tower; The gas phase outlet of the dry powder hydrolysis reactor is connected to the gas phase inlet of the tail gas scrubbing tower.

7. The processing system according to claim 6, characterized in that, The dry powder hydrolysis reactor includes a reactor body and an empty tower located on top of the reactor body and communicating with the reactor body; The gas phase outlet is located at the top of the empty tower, and the empty tower has a liquid phase inlet; The vessel is used for hydrolysis treatment.

8. The processing system according to claim 7, characterized in that, The top of the empty tower also has a nitrogen inlet; and / or, The empty tower also has a lime milk inlet.

9. The processing system according to claim 7 or 8, characterized in that, Also includes: Dry powder hydrolysate condenser; The outlet of the reactor body is connected to the inlet of the dry powder hydrolysate condenser, and the outlet of the dry powder hydrolysate condenser is connected to the empty tower.

10. The processing system according to any one of claims 6-8, characterized in that, Also includes: Tail gas tower pump; The bottom of the tail gas scrubbing tower is connected to the inlet of the tail gas tower pump, and the outlet of the tail gas tower pump is connected to the top of the tail gas scrubbing tower.

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