Initial rainwater cleaning and recycling device and method in combined soda production

Abstract

The invention discloses an initial rainwater cleaning and recycling device and method in combined-soda production, the device comprises an open trench, an initial rainwater collecting pool and a clean rainwater bucket, and the open trench is arranged around the processes of carbon filtration, calcination, crystallization, refrigeration, ammonium drying and dry ammonium packaging in combined-soda production; the initial rainwater collecting pool comprises a sedimentation pool, an oil separation pool and a clean water pool, the sedimentation pool is connected with the open trench through a blind ditch, an ammonia nitrogen online analyzer and an automatic control valve are arranged in the blind ditch, the upper portion of the sedimentation pool is communicated with the oil separation pool, a liquid level meter is arranged in the oil separation pool, the automatic control valve is arranged between the oil separation pool and the clean water pool, the clean water pool is closed, and a breathing tube is arranged on the top of the clean water pool. A liquid level meter and a submersible pump are arranged in the shell; an inlet of the clean rainwater bucket is connected with the clean water tank, and an outlet is connected with a washing water head tank of a carbon filtration process through a clean rainwater pipeline and used for supplementing washing water of the belt filter. The recycling process is simple and efficient, recycled rainwater is clean and free of side effects, the production cost can be reduced, and the product quality of sodium bicarbonate and sodium carbonate is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of combined caustic soda production technology, and in particular relates to a device and method for cleaning and recovering initial rainwater in combined caustic soda production. Background Art

[0002] Due to the characteristics of the soda ash production process, there are leakage of mother liquor and volatilization of ammonia in the production area during the production process. When it rains, the ammonia nitrogen value in the initial rainwater exceeds the standard and cannot be discharged, so it needs to be recycled into the production system. At present, the initial rainwater is only recycled through the collection pool. When the ammonia nitrogen value of the rainwater meets the standard, the rainwater is discharged. The rainwater in the recycling pool will gradually return to the production system in the future as supplementary water and enter the production system. However, since the rainwater contains debris such as mud and sand, it cannot be cleanly recycled. Therefore, the initial rainwater generally enters the miscellaneous water barrel. When there is a need to supplement production water, it directly enters the MⅠ barrel, which only plays the role of recycling and supplementing production water. In addition, since the rainwater contains impurities, it will also affect the cleanliness of the mother liquor, resulting in impurities such as black spots in the product, affecting product quality. Summary of the invention

[0003] Technical problems to be solved: In response to the above technical problems, the present invention provides a device and method for cleaning and recovering initial rainwater in the production of combined alkali. Not only is the recovery process simple and efficient, the recovered rainwater is clean and has no side effects, but it can also reduce production costs and improve the product quality of heavy alkali and soda ash.

[0004] Technical solution: A device for cleaning and recovering initial rainwater in the production of soda ash, comprising an open ditch, an initial rainwater collection pool and a clean rainwater barrel. The open ditch is arranged around the carbon filtration, calcination, crystallization, refrigeration, dry ammonium and dry ammonium packaging processes in the production of soda ash, and is used to collect the initial rainwater in the production of soda ash; the initial rainwater collection pool comprises a sedimentation tank, a grease trap and a clear water tank. The sedimentation tank is connected to the open ditch through a concealed ditch, and an ammonia nitrogen online analyzer and an automatic control valve are provided in the concealed ditch. The upper part of the sedimentation tank is connected to the grease trap, and a liquid level gauge is provided in the grease trap. An automatic control valve is provided between the grease trap and the clear water tank. The clear water tank is closed, and a breathing tube is provided on the top, and a liquid level gauge and a submersible pump are provided inside; the inlet of the clean rainwater barrel is connected to the clear water tank, and the outlet is connected to the high-level tank for washing water of the carbon filtration process through a clean rainwater pipeline, and is used for replenishing water for washing water with the filter.

[0005] Preferably, the clean rainwater pipeline is also connected to the crystallizer of the crystallization process through the miscellaneous water pump outlet pipeline for cleaning the crystallizer.

[0006] Preferably, a clean rainwater pump is provided on the clean rainwater pipeline.

[0007] Preferably, a filter is provided on the clean rainwater pipeline, and the filter is an automatic backwash filter.

[0008] Furthermore, an inlet pressure gauge and an inlet automatic valve are provided on the inlet side of the filter on the clean rainwater pipeline, and an outlet pressure gauge and an outlet automatic valve are provided on the outlet side; the clean rainwater pipeline is also connected to the outlet of the filter through a bypass water pipe, and a bypass automatic valve is provided on the bypass water pipe for backwashing the filter; the filter is also connected to a sewage pipe leading to the sedimentation tank, and a sewage automatic valve is provided on the sewage pipe.

[0009] Preferably, a grid is provided between the sedimentation tank and the grease trap to isolate floating objects on the water surface.

[0010] A method for cleaning and recycling initial rainwater in combined alkali production comprises the following steps: S1. Collect initial rainwater through open ditch and test ammonia nitrogen value in the dark ditch. When the ammonia nitrogen value is greater than 15mg / L, the dark ditch is opened to collect rainwater into the sedimentation tank; otherwise, the dark ditch is closed and the rainwater is discharged; S2. After the rainwater enters the sedimentation tank, it flows into the grease trap through the upper overflow. When the liquid level in the grease trap is ≥80%, the automatic control valve between the grease trap and the clean water tank opens to continuously collect rainwater into the clean water tank; when the liquid level in the grease trap is ≤30%, the automatic control valve between the grease trap and the clean water tank closes, and the grease trap continues to collect rainwater; S3. After the rainwater enters the clean water tank, when the liquid level in the clean water tank is ≥80%, the submersible pump is turned on to continuously collect the clean rainwater into the clean rainwater barrel; when the liquid level in the clean water tank is ≤5%, the submersible pump is turned off and the clean water tank continues to collect rainwater; S4. After the rainwater enters the clean rainwater barrel, it enters the high-level tank of the carbon filter process through the clean rainwater pipeline and serves as the wash water supplement water for the filter.

[0011] Preferably, when the amount of supplementary water in S4 is insufficient, the dark ditch in S1 is kept open.

[0012] Preferably, a filter is provided on the clean rainwater pipeline in S4, and inlet and outlet pressure gauges and inlet and outlet automatic valves are provided on the inlet and outlet sides of the filter; the clean rainwater pipeline is also connected to the outlet of the filter through a bypass water pipe, and a bypass automatic valve is provided on the bypass water pipe; the filter is also connected to a sewage pipe leading to the sedimentation tank, and a sewage automatic valve is provided on the sewage pipe; when the inlet and outlet pressure difference of the filter is ≥0.15MPa, the inlet and outlet automatic valves are closed, and the bypass automatic valve and the sewage automatic valve are opened to automatically backwash the filter.

[0013] Preferably, the clean rainwater pipeline in S4 is also connected to the crystallizer of the crystallization process through the outlet pipeline of the miscellaneous water pump, and the clean rainwater is used as production water to clean the crystallizer.

[0014] Beneficial effects: On the one hand, the present invention can clean and recycle the initial rainwater with excessive ammonia nitrogen value in the production of soda ash, thereby improving the quality of heavy alkali and soda ash products and reducing production costs; on the other hand, it can realize full-process automated rainwater recycling, reducing the workload of manual control. In addition, when the mother liquor of the soda ash production shrinks and the required supplementary water volume is insufficient, all the rainwater can be recycled without affecting the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the device arrangement structure of the present invention; Figure 2 It is a schematic diagram of the structure of the initial rainwater collection pool of the present invention; Figure 3 It is a pipeline arrangement diagram for backwashing of the filter of the present invention; The numbers in the figure represent the following: 1. Compression process, 2. Carbon filtration process, 3. Calcination process, 4. Heavy ash process, 5. Soda ash packaging process, 6. Crystallization process, 7. Refrigeration process, 8. Dry ammonium process, 9. Dry ammonium packaging process, 10. Open ditch, 11. Initial rainwater collection pool, 12. Clean rainwater barrel, 13. Miscellaneous water barrel, 14. Rainwater underground pipe network, 11-1. Sedimentation tank, 11-2. Grease separator, 11-3. Clean water tank. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Example 1

[0017] like Figure 1 As shown, in the combined alkali production boundary area I and the combined alkali production boundary area II, the initial rainwater cleaning and recovery device in the combined alkali production is set, including an open ditch 10, an initial rainwater collection pool 11 and a clean rainwater barrel 12. The combined alkali production boundary area I is provided with relevant equipment for the compression process 1, the carbon filtration process 2, the calcination process 3, the heavy ash process 4, and the soda ash packaging process 5, and the combined alkali production boundary area II is provided with relevant equipment for the crystallization process 6, the refrigeration process 7, the dry ammonium process 8, and the dry ammonium packaging process 9. An underground rainwater pipe network 14 is provided under the combined alkali production boundary area for rainwater discharge. The open ditch 10 is arranged around the carbon filtration, calcination, crystallization, refrigeration, dry ammonium and dry ammonium packaging processes, and is used to collect the initial rainwater in the combined alkali production. An automatic control valve is provided at the connection between the open ditch 10 and the rainwater underground pipe network 14.

[0018] like Figure 2As shown, the initial rainwater collection pool 11 includes a sedimentation tank 11-1, a grease trap 11-2 and a clean water tank 11-3, which adopts a three-stage separation arrangement to remove impurities such as mud, surface floating objects, and oil pollution in rainwater, thereby improving the cleanliness of the recovered initial rainwater. The sedimentation tank 11-1 is connected to the open ditch 10 through a dark ditch, and an ammonia nitrogen online analyzer and an automatic control valve are arranged in the dark ditch; the upper part of the sedimentation tank 11-1 is connected to the grease trap 11-2, and a grid is arranged between the two to isolate floating objects on the water surface; the grease trap 11-2 is used to remove oil pollution in rainwater, and a liquid level gauge is arranged therein, and an automatic control valve is arranged between the grease trap 11-2 and the clean water tank 11-3, and the switch of the automatic control valve can be automatically controlled by the liquid level gauge; the clean water tank 11-3 is a closed type, with a breathing tube on the top, and a liquid level gauge and a submersible pump are arranged inside.

[0019] The inlet of the clean rainwater barrel 12 is connected to the clean water tank 11-3, and the outlet is connected to the high-level tank of the carbon filter process 2 through the clean rainwater pipeline, and is used as supplementary water for the belt filter washing. The increase in the amount of washing water can reduce the heavy alkali salt content and improve the quality of heavy alkali and soda ash. A clean rainwater pump is provided on the clean rainwater pipeline, and is also connected to the crystallizer of the crystallization process 6 through the miscellaneous water pump outlet pipeline, which is used to clean the crystallizer and reduce the cost of using production water. Among them, the miscellaneous water pump outlet pipeline is also connected to the miscellaneous water barrel 13 of the alkali production equipment, which is used to provide water for cleaning the crystallizer to the crystallization process.

[0020] The clean rainwater pipeline is provided with a filter, which is an automatic backwash filter. Figure 3 As shown, an inlet pressure gauge and an inlet automatic control valve are provided on the inlet side of the filter on the clean rainwater pipeline, and an outlet pressure gauge and an outlet automatic control valve are provided on the outlet side; the clean rainwater pipeline is also connected to the outlet of the filter through a bypass water pipe, and a bypass automatic control valve is provided on the bypass water pipe for backwashing the filter; the filter is also connected to a sewage pipe leading to a sedimentation tank 11-1, and a sewage automatic control valve is provided on the sewage pipe, which can not only avoid the indiscriminate discharge of sewage during sewage discharge, but also can use the sedimentation tank 11-1 to settle the debris and further recover the clean rainwater.

[0021] The method for cleaning and recycling initial rainwater in combined alkali production using the above device comprises the following steps: S1. Collect initial rainwater through the open ditch 10, detect the ammonia nitrogen value in the dark ditch, and when the ammonia nitrogen value is greater than 15 mg / L, the automatic control valve of the dark ditch automatically opens to collect rainwater into the sedimentation tank 11-1, and the automatic control valve at the connection between the open ditch 10 and the rainwater underground pipe network 14 automatically closes; otherwise, the automatic control valve of the dark ditch automatically closes, stops collecting rainwater, and the automatic control valve at the connection between the open ditch 10 and the rainwater underground pipe network 14 automatically closes, and the rainwater that meets the external discharge standard is discharged; S2. After the rainwater enters the sedimentation tank 11-1, it flows into the grease trap 11-2 through the upper overflow. When the liquid level in the grease trap 11-2 is ≥80%, the automatic control valve between the grease trap 11-2 and the clean water tank 11-3 opens, and the rainwater continues to flow into the clean water tank 11-3; when the liquid level in the grease trap 11-2 is ≤30%, the automatic control valve between the grease trap 11-2 and the clean water tank 11-3 closes, and the grease trap 11-2 continues to collect rainwater; S3. After the rainwater enters the clean water tank 11-3, when the liquid level in the clean water tank 11-3 is ≥80%, the submersible pump is turned on to continuously collect the clean rainwater into the clean rainwater barrel 12; when the liquid level in the clean water tank 11-3 is ≤5%, the submersible pump is turned off, and the clean water tank 11-3 continues to collect rainwater; S4. After the rainwater enters the clean rainwater barrel 12, it enters the high-level tank of the carbon filter process through the clean rainwater pipeline and serves as the wash water supplement water for the filter.

[0022] When the mother liquor shrinks greatly in the combined alkali production and the required supplementary water in S4 is insufficient, the culvert in S1 can be artificially controlled to remain open to recycle all the rainwater.

[0023] When the inlet and outlet pressure difference of the filter is ≥0.15MPa, the inlet and outlet automatic control valves are closed, the bypass automatic control valve and the sewage automatic control valve are opened, and the filter screen in the filter is automatically backwashed while the clean rainwater pump is continuously turned on to achieve fully automatic control.

[0024] When the crystallization process requires cleaning of the crystallizer, the clean rainwater in the clean rainwater barrel 12 can also be sent into the crystallizer through the outlet pipeline of the miscellaneous water pump to be used as production water to clean the crystallizer, thereby reducing the use of production water and reducing costs.

Claims

1. An initial rainwater cleaning and recovery device in the production of combined alkali, characterized in that: The invention comprises an open ditch (10), an initial rainwater collection pool (11) and a clean rainwater barrel (12). The open ditch (10) is arranged around the carbon filtration, calcination, crystallization, refrigeration, dry ammonium and dry ammonium packaging processes of the combined alkali production, and is used to collect the initial rainwater in the combined alkali production. The initial rainwater collection pool (11) comprises a sedimentation tank (11-1), a grease trap (11-2) and a clean water tank (11-3). The sedimentation tank (11-1) is connected to the open ditch (10) via a dark ditch. An ammonia nitrogen online analyzer is arranged in the dark ditch. and an automatic control valve, the upper part of the sedimentation tank (11-1) is connected to the grease trap (11-2), a liquid level gauge is provided in the grease trap (11-2), an automatic control valve is provided between the grease trap (11-2) and the clean water tank (11-3), the clean water tank (11-3) is closed, a breathing tube is provided on the top, and a liquid level gauge and a submersible pump are provided inside; the inlet of the clean rainwater barrel (12) is connected to the clean water tank (11-3), and the outlet is connected to the washing water high-level tank of the carbon filtration process through the clean rainwater pipeline, and is used for washing water replenishment of the filter machine.

2. The initial rainwater cleaning and recycling device in the combined alkali production according to claim 1 is characterized in that: The clean rainwater pipeline is also connected to the crystallizer of the crystallization process through the miscellaneous water pump outlet pipeline for cleaning the crystallizer.

3. The initial rainwater cleaning and recycling device in the combined alkali production according to claim 1 is characterized in that: The clean rainwater pipeline is provided with a clean rainwater pump.

4. The initial rainwater cleaning and recycling device in the combined alkali production according to claim 1 is characterized in that: The clean rainwater pipeline is provided with a filter, and the filter is an automatic backwashing filter.

5. The initial rainwater cleaning and recycling device in the combined alkali production according to claim 4 is characterized in that: The clean rainwater pipeline is provided with an inlet pressure gauge and an inlet automatic control valve on the inlet side of the filter, and an outlet pressure gauge and an outlet automatic control valve on the outlet side; the clean rainwater pipeline is also connected to the outlet of the filter through a bypass water pipe, and the bypass water pipe is provided with a bypass automatic control valve for backwashing the filter; the filter is also connected to a sewage pipe leading to the sedimentation tank (11-1), and the sewage pipe is provided with a sewage discharge automatic control valve.

6. The initial rainwater cleaning and recycling device in the combined alkali production according to claim 1 is characterized in that: A grid is provided between the sedimentation tank (11-1) and the grease trap (11-2) to isolate floating objects on the water surface.

7. A method for cleaning and recycling initial rainwater in the combined alkali production using the device of claim 1, characterized in that: The steps include: S1. Collect initial rainwater through the open ditch (10) and test the ammonia nitrogen value in the dark ditch. When the ammonia nitrogen value is greater than 15 mg / L, the dark ditch is opened to collect the rainwater into the sedimentation tank (11-1); otherwise, the dark ditch is closed and the rainwater is discharged; S2. After the rainwater enters the sedimentation tank (11-1), it flows into the grease trap (11-2) through the upper overflow. When the liquid level in the grease trap (11-2) is ≥80%, the automatic control valve between the grease trap (11-2) and the clean water tank (11-3) opens, and the rainwater continues to flow into the clean water tank (11-3). When the liquid level in the grease trap (11-2) is ≤30%, the automatic control valve between the grease trap (11-2) and the clean water tank (11-3) closes, and the grease trap (11-2) continues to collect rainwater. S3. After the rainwater enters the clean water tank (11-3), when the liquid level in the clean water tank (11-3) is ≥80%, the submersible pump is turned on to continuously collect the clean rainwater into the clean rainwater barrel (12); when the liquid level in the clean water tank (11-3) is ≤5%, the submersible pump is turned off, and the clean water tank (11-3) continues to collect rainwater; S4. After the rainwater enters the clean rainwater barrel (12), it enters the high-level tank of the carbon filter process through the clean rainwater pipeline and serves as the wash water supplement water for the filter.

8. The method for cleaning and recycling initial rainwater in combined alkali production according to claim 7, characterized in that: When the amount of supplementary water in S4 is insufficient, the culvert in S1 is kept open.

9. The method for cleaning and recycling initial rainwater in combined alkali production according to claim 7, characterized in that: In the S4, a filter is provided on the clean rainwater pipeline, and an inlet and outlet pressure gauge and an inlet and outlet automatic control valve are provided on the inlet and outlet sides of the filter; the clean rainwater pipeline is also connected to the outlet of the filter through a bypass water pipe, and a bypass automatic control valve is provided on the bypass water pipe; the filter is also connected to a sewage pipe leading to the sedimentation tank (11-1), and a sewage automatic control valve is provided on the sewage pipe; when the inlet and outlet pressure difference of the filter is ≥0.15MPa, the inlet and outlet automatic control valves are closed, and the bypass automatic control valve and the sewage automatic control valve are opened to automatically backwash the filter.

10. The method for cleaning and recycling initial rainwater in combined alkali production according to claim 7, characterized in that: The clean rainwater pipeline in S4 is also connected to the crystallizer of the crystallization process through the outlet pipeline of the miscellaneous water pump, and the clean rainwater is used as production water to clean the crystallizer.

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