Chlorination tower high-salt tail water treatment system

Abstract

The utility model provides a kind of chlorination tower high salt tail water treatment system, belong to wastewater treatment technical field, comprising: feeding pump, feed preheater, heat exchanger and separator connected in turn;Steam outlet of the top of separator is connected with the import of compressor, and the export of compressor is connected with the steam import of heat exchanger;The crystallization material port of separator is connected with thickener, centrifuge, drying machine and salt storage tank in turn by discharging pump;The circulating material port of separator is connected with the material import of heat exchanger by circulating pump;The hot medium outlet of feed preheater is connected with cooling water tank, and the outlet of cooling water tank is connected with the bottom tail water pool of chlorination tower by water pump, and cooling water tank is equipped with cooling water make-up pipeline, and the top of cooling water tank is connected with vacuum pump;The feed inlet of separator is connected with spray pipe, and spray head is equipped on spray pipe.The system separator evaporation effect is good, and secondary steam generation is large, and high salt tail water from chlorination tower can be effectively treated, to ensure the production safety of chlorination tower.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a high-salinity tailwater treatment system for chlorination towers. Background Technology

[0002] The tail gas (such as chlorine) produced during the acetylene chlorination reaction is absorbed by the circulating tailwater in the chlorination tower and enters the tailwater pool at the bottom of the tower. Liquid alkali needs to be added to the tailwater pool continuously for neutralization, thus generating salts (such as sodium chloride and sulfate). The salt concentration in the tailwater continuously increases during the circulation absorption process. Excessive salt concentration can cause crystallization blockage in the jet pump of the acetylene chlorination tower, affecting the vacuum level of the chlorination tower and seriously impacting its safe operation and posing production safety hazards. Therefore, the salt concentration in the chlorination tower should normally be controlled below 12%. If it exceeds this range, the high-concentration brine must be discharged and fresh water added. However, since the salt content in the tailwater exceeds 120,000 ppm (i.e., 12%), it does not meet the discharge requirements, and this high-salinity tailwater needs to be purified or recycled.

[0003] In recent years, technologies for treating high-salinity wastewater have mainly focused on membrane separation, evaporation crystallization, and biological treatment. Membrane separation technology has attracted considerable attention due to its high efficiency and energy saving, but the cost and lifespan of membrane materials still need further improvement. Biological treatment technology is highly regarded for its environmental friendliness, but it is currently still in the laboratory research stage and is some distance from large-scale application. Evaporation crystallization technology is suitable for treating high-concentration brine and has a wide range of applications. However, existing MVR evaporation crystallizers still have some problems during operation, such as: low evaporation efficiency of wastewater within the separator, resulting in insufficient secondary steam generation, which can easily affect the heating efficiency of the heat exchanger; and the formation of secondary steam containing liquid droplets, requiring separation by a gas-liquid separator, which increases the footprint and processing cost of the MVR evaporation crystallization unit. Therefore, a high-salinity wastewater treatment system for chlorination towers is needed that can effectively treat high-salinity wastewater, reduce energy consumption and costs, and ensure production safety. Utility Model Content

[0004] This invention provides a high-salt tailwater treatment system for chlorination towers, which solves the problems of low evaporation efficiency resulting in insufficient secondary steam generation when high-salt tailwater is treated by MVR evaporation crystallizers, the need for additional gas-liquid separators to separate entrained droplets from the secondary steam, and high treatment costs.

[0005] This utility model provides a high-salt tailwater treatment system for a chlorination tower, comprising: a feed pump, a feed preheater, a heat exchanger, and a separator connected sequentially along the material flow direction; the steam outlet at the top of the separator is connected to the inlet of a compressor, the outlet of the compressor is connected to the steam inlet of the heat exchanger, and the steam inlet of the heat exchanger is also connected to an external steam pipeline; the crystallization port of the separator is connected to a thickener via a discharge pump; the outlet of the thickener is connected to a centrifuge, and the solid outlet of the centrifuge is sequentially connected to a dryer and a salt storage tank; the circulation port of the separator is connected to the material inlet of the heat exchanger via a circulation pump, and the liquid outlet of the centrifuge is also connected to the material inlet of the heat exchanger; the condensate outlet of the heat exchanger is connected to the heat medium inlet of the feed preheater, the heat medium outlet of the feed preheater is connected to a cooling water tank, the outlet of the cooling water tank is connected to the tailwater pool at the bottom of the chlorination tower via a water pump, the cooling water tank is also equipped with a cooling water makeup pipeline, and the top of the cooling water tank is connected to a vacuum pump; a spray pipe is connected to the feed inlet of the separator, and spray heads are provided on the spray pipe.

[0006] Furthermore, the outlet of the feed pump is connected to the material inlet of the feed preheater, the material outlet of the feed preheater is connected to the material inlet of the heat exchanger, and the material outlet of the heat exchanger is connected to the feed inlet of the separator.

[0007] Furthermore, the heat exchanger is a single-pass shell-and-tube heat exchanger; the compressor is a centrifugal compressor.

[0008] Furthermore, the separator has a cylindrical structure, with a sleeve inside. The spray pipe and spray head are located on the upper part of the sleeve. The diameter of the sleeve is not less than 2 / 3 of the diameter of the separator, and the height of the sleeve is 1 / 3 of the height of the separator.

[0009] Furthermore, the lower part of the separator is provided with an inverted conical guide plate, the top of the guide plate is sealed to the inner wall of the separator, and the bottom of the guide plate is provided with a guide pipe, which is suspended in the lower part of the separator; there is a gap between the sleeve and the top of the guide plate, and the part below the guide plate is the crystallization chamber.

[0010] Furthermore, a circulation port is provided on the side wall of the separator located at the top of the crystallization chamber; a crystallization port is provided at the bottom of the separator.

[0011] Furthermore, there is a gap between the steam outlet at the top of the separator and the sleeve, and a wire mesh demister and a baffle plate demister are installed sequentially from top to bottom.

[0012] Furthermore, a level gauge and a temperature sensor are installed in the crystallization chamber, and a pressure sensor is also provided in the separator.

[0013] The high-salinity tailwater treatment system for chlorination towers provided by this utility model, by integrating with the production process, can promptly transfer and effectively treat the high-salinity tailwater from the chlorination tower, reduce wastewater discharge, ensure the safety of chlorination tower production, reduce production costs, improve resource utilization, and reduce environmental pollution, which is in line with the current green and sustainable development concept.

[0014] The separator in this system uses a spray method for feeding, which increases the evaporation rate and improves the evaporation efficiency, thereby increasing the amount of secondary steam generated. This is beneficial for improving the efficiency of the heat exchanger and the system's processing efficiency, greatly reducing energy consumption, and saving system operating costs.

[0015] The condensate produced by this system can be reused in the chlorination tower, and the resulting crystalline salt is also economically beneficial, achieving the recycling of tailwater and recovery of byproducts. At the same time, the system operates stably and is easy to maintain, providing a reliable guarantee for the company's high-salinity tailwater treatment over the long term, ensuring stable operation of the chlorination tower, reducing production safety hazards, ensuring the safe operation of acetylene chlorination, and creating significant economic benefits. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of a high-salt tailwater treatment system for a chlorination tower provided in one embodiment of this utility model; Figure 2 This is a schematic diagram of the separator provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the separator provided for another embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Feed pump, 2. Feed preheater, 3. Heat exchanger, 4. Separator, 5. Compressor, 41. Steam outlet, 42. Crystallizer inlet, 43. Circulating feed inlet, 44. Spray pipe, 45. Sleeve, 46. Crystallization chamber, 47. Wire mesh demister, 48. Baffle plate demister, 49. Feed inlet, 61. Discharge pump, 62. Thickener, 63. Centrifuge, 64. Dryer, 65. Salt storage tank, 66. Circulating pump, 71. Cooling water tank, 72. Water pump, 73. Vacuum pump, 461. Baffle plate, 462. Baffle pipe. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are also within the protection scope of this utility model.

[0020] like Figure 1 and Figure 2 This utility model discloses a high-salt tailwater treatment system for a chlorination tower, comprising: a feed pump 1, a feed preheater 2, a heat exchanger 3, and a separator 4 connected sequentially along the material flow direction; the steam outlet 41 at the top of the separator 4 is connected to the inlet of a compressor 5, the outlet of the compressor 5 is connected to the steam inlet of the heat exchanger 3, and the steam inlet of the heat exchanger 3 is also connected to an external steam pipeline; the crystallization port 42 of the separator 4 is connected to a thickener 62 via a discharge pump 61; the discharge port of the thickener 62 is connected to a centrifuge 63, and the solid outlet of the centrifuge 63 is sequentially connected to a dryer 64 and a salt storage tank 65; The circulating feed port 43 of the centrifuge 4 is connected to the material inlet of the heat exchanger 3 via the circulating pump 66, and the liquid outlet of the centrifuge 63 is also connected to the material inlet of the heat exchanger 3; the condensate outlet of the heat exchanger 3 is connected to the hot medium inlet of the feed preheater 2, the hot medium outlet of the feed preheater 2 is connected to the cooling water tank 71, the outlet of the cooling water tank 71 is connected to the tail water pool at the bottom of the chlorination tower via the water pump 72, the cooling water tank 71 is also equipped with a cooling water makeup pipeline, and the top of the cooling water tank 71 is connected to the vacuum pump 73; the feed port 49 of the separator 4 is connected to a spray pipe 44, and the spray pipe 44 is equipped with a spray head.

[0021] High-salt tailwater (e.g., salt concentration > 12%) from the bottom tailwater pool of the chlorination tower is preheated in the feed preheater 2 via feed pump 1, then heated by heat exchanger 3 before entering separator 4. The heated material enters separator 4 via spray pipe 44 and spray head, where it is separated into steam and liquid phases. The steam is pressurized by compressor 5 to form secondary steam, which then passes through heat exchanger 3 and feed preheater 2 as a heat source. The condensate formed during heat exchange is temporarily stored in cooling water tank 71 and can be reused as makeup water for the chlorination tower. Non-condensable gases are released into the environment via vacuum pump 73. Cooling water makeup lines installed on cooling water tank 71 can be used to replenish water to cooling water tank 71, reducing the cooling water temperature and increasing the system vacuum. The supernatant in the liquid phase of separator 4 is sent to heat exchanger 3 by circulation pump 66 and circulated together with the new feed. The lower layer of thick liquid in the liquid phase is sent to thickener 62 by discharge pump 61 and then centrifuged by centrifuge 63. The resulting solid is dried by dryer 64 and stored in salt storage tank 65. The resulting liquid is also circulated together with the new feed.

[0022] This system receives high-salt tailwater from the chlorination tower, which has a relatively small processing capacity. To avoid insufficient secondary steam, the feed to separator 4 is achieved through spraying, increasing the evaporation rate and improving evaporation efficiency. This allows external steam to be used only during startup. Once the system is operating normally, the secondary steam can meet the system's needs, significantly reducing energy consumption. The condensate produced by the system can be reused in the chlorination tower, and the resulting crystalline salt also has economic benefits. This system can treat high-salt tailwater from the chlorination tower in a timely and effective manner, reducing wastewater discharge, ensuring the safety of chlorination tower production, reducing environmental pollution, and achieving resource recycling, which aligns with the current green and sustainable development concept.

[0023] Preferably, the outlet of the feed pump 1 is connected to the material inlet of the feed preheater 2, the material outlet of the feed preheater 2 is connected to the material inlet of the heat exchanger 3, and the material outlet of the heat exchanger 3 is connected to the feed inlet 49 of the separator 4.

[0024] Preferably, heat exchanger 3 is a single-pass shell-and-tube heat exchanger; compressor 5 is a centrifugal compressor. The single-pass shell-and-tube heat exchanger ensures that materials maintain a consistently high flow rate within heat exchanger 3, avoiding scaling and fouling caused by reduced solvent levels. This significantly reduces the risk of scaling and clogging, ensuring stable system operation. The impeller of compressor 5 is made of TC4 stainless steel (such as the rotor and the cavity of the flow passage), offering excellent corrosion resistance. Furthermore, this type of compressor 5 features low noise, minimal energy loss, and high energy efficiency, ensuring stable and safe system operation.

[0025] like Figure 2 Preferably, the separator 4 has a cylindrical structure, and a sleeve 45 is provided inside the separator 4. The spray pipe 44 and the spray head are arranged on the upper part of the sleeve 45. The diameter of the sleeve 45 is not less than 2 / 3 of the diameter of the separator 4, and the height of the sleeve 45 is 1 / 3 of the height of the separator 4.

[0026] The heated material enters the larger separator 4, where the pressure decreases, facilitating gas-liquid separation. The spray pipe 44 and spray heads ensure the tailwater is fed in a mist-like spray pattern, further dispersing and refining it, significantly increasing the surface area. This increases the tailwater evaporation rate or shortens the evaporation time, improving secondary steam generation and enhancing the efficiency of the heat exchanger 3 and the overall system processing efficiency, while also saving on system operating costs. The evaporated steam enters the upper part of the separator 4 through the top outlet of the sleeve 45, and is finally discharged to the compressor 5 through the top steam outlet 41. The sleeve 45 can be fixed inside the separator 4 by a connecting rod; this is a standard configuration, and the shape, number, and position of the connecting rod are not limited or shown. The structure and number of spray heads are also not limited; commonly used spray heads in this field can be selected based on production volume, pressure settings, etc.

[0027] like Figure 3Preferably, the lower part of the separator 4 is provided with a guide plate 461 with an inverted conical structure. The top of the guide plate 461 is sealed to the inner wall of the separator 4. The bottom of the guide plate 461 is provided with a guide pipe 462, which is suspended in the lower part of the separator 4. There is a gap between the sleeve 45 and the top of the guide plate 461, and the part below the guide plate 461 is the crystallization chamber 46.

[0028] Preferably, a circulation port 43 is provided on the side wall of the separator 4 located at the top of the crystallization chamber 46; and a crystallization port 42 is provided at the bottom of the separator 4.

[0029] The liquid phase, after being sprayed and evaporated in the sleeve 45, falls and is collected by the downward-sloping guide plate 461 into the guide pipe 462, and finally discharged into the crystallization chamber 46 at the bottom of the separator 4. As the processing time increases, the concentration of the liquid phase gradually increases. The clear liquid in the upper layer can be reheated and sprayed by the circulating pump 66 to achieve continuous heating, concentration, evaporation and crystallization of the tail water. After the crystallized liquid in the lower layer accumulates to a certain concentration (preset by the technicians), it is sent to the thickener 62 by the discharge pump 61 to facilitate subsequent solid-liquid separation and drying of the crystallized salt.

[0030] like Figure 3 Preferably, there is a gap between the steam outlet 41 at the top of the separator 4 and the sleeve 45, and a wire mesh demister 47 and a baffle plate demister 48 are arranged sequentially from top to bottom. The steam generated by the evaporation of the tail water will carry tiny liquid droplets and rise in the separator 4. These droplets are captured and separated by the baffle plate demister 48 and the wire mesh demister 47, which can prevent the entrainment of mist from damaging the compressor 5, improve the quality of the condensate water, and avoid the need for additional separate gas-liquid separators 4 and other equipment to separate secondary steam and droplets, thus reducing the overall cost of the equipment and making the system structure more compact and space-saving. The wire mesh demister 47 and the baffle plate demister 48 are commonly used components in the field, and they can be equipped with flushing pipes for cleaning. The installation of the flushing pipes is also a conventional installation and will not be described or limited here.

[0031] Preferably, a level gauge and a temperature sensor are installed in the crystallization chamber 46, and a pressure sensor is also provided in the separator 4.

[0032] It should be noted that arrows without reference numerals indicate the flow direction of gas-liquid mixtures, gas phases, or liquid phases.

[0033] In the aforementioned high-salt tailwater treatment system for the chlorination tower, the high-salt tailwater with a salt concentration of 12-18 wt% from the tailwater pool at the bottom of the chlorination tower is preheated in the feed preheater 2 via feed pump 1 at a feed rate of 3500 kg / h. After being heated by heat exchanger 3, it enters separator 4. The heated material enters separator 4 through spray pipe 44 and spray head, where it is separated into steam and liquid phases. The liquid phase is collected by the downward-sloping guide plate 461 into guide pipe 462 and finally discharged into crystallization chamber 46 at the bottom of separator 4. The steam carries tiny liquid droplets as it rises in separator 4, where it is captured and separated by baffle demister 48 and wire mesh demister 47 before being discharged through steam outlet 41.

[0034] Steam is pressurized by compressor 5 to form secondary steam. Compressor 5 has an inlet temperature of 90℃ and an outlet temperature of 108℃. The secondary steam passes through heat exchanger 3 and feed preheater 2 as heat sources. The condensate formed by the heat exchange is temporarily stored in cooling water tank 71. The salt concentration in the condensate is less than 50ppm and can be used as makeup water for the chlorination tower tailwater tank and reused in the chlorination tower. Non-condensable gases are released into the environment through vacuum pump 73. The cooling water makeup line installed on cooling water tank 71 can be used to replenish water to cooling water tank 71, which can reduce the cooling water temperature and improve the system vacuum.

[0035] As processing time increases, the concentration of the liquid phase in the crystallization chamber 46 of separator 4 gradually increases. The upper clear liquid is sent to heat exchanger 3 via circulation pump 66 and circulated together with the new feed. The lower thick liquid is periodically sent to thickener 62 via discharge pump 61, with an external discharge rate of ≤5t / d. After centrifugation by centrifuge 63, the resulting solid is dried by dryer 64 and stored in salt storage tank 65. The resulting liquid is also circulated together with the new feed. Through the implementation of this system, the daily salt output is measured at 3 tons, and the annual salt output reaches 990 tons. At a unit price of 200 yuan per ton, the economic benefit is 198,000 yuan, creating good economic benefits.

[0036] It should be noted that the detailed structure of some devices in this utility model is not described in detail, but belongs to the prior art known to those skilled in the art, and therefore will not be described again here. In addition, the parts of this device not described are the same as or can be implemented using existing technology.

[0037] It should be noted that those skilled in the art, under the guidance of this utility model, can also make some modifications to the design of the above system. For example, the equipment in the system is also equipped with level gauges, overflow / nitrogen pipelines, etc.; pumps, pressure sensors, flow meters or temperature sensors are installed on the conveying pipelines inside the system in different units or devices, and different valves, such as pressure relief valves, pressure regulating valves, safety valves, pneumatic valves, etc., are also installed to regulate and stabilize the pressure of the entire system, and the opening degree of the valves can also be adjusted to regulate the flow rate of materials in the pipeline, etc.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A high-salinity tailwater treatment system for a chlorination tower, characterized in that, include: The feed pump, feed preheater, heat exchanger, and separator are connected sequentially along the material flow direction. The steam outlet at the top of the separator is connected to the compressor inlet, the compressor outlet is connected to the steam inlet of the heat exchanger, and the steam inlet of the heat exchanger is also connected to an external steam pipeline. The crystallization port of the separator is connected to a thickener via a discharge pump. The discharge port of the thickener is connected to a centrifuge, and the solid outlet of the centrifuge is sequentially connected to a dryer and a salt storage tank. The circulation port of the separator is connected to the material inlet of the heat exchanger via a circulation pump, and the liquid outlet of the centrifuge is also connected to the material inlet of the heat exchanger. The condensate outlet of the heat exchanger is connected to the heat medium inlet of the feed preheater, the heat medium outlet of the feed preheater is connected to a cooling water tank, and the outlet of the cooling water tank is connected to the tailwater pool at the bottom of the chlorination tower via a water pump. The cooling water tank is also equipped with a cooling water makeup pipeline, and the top of the cooling water tank is connected to a vacuum pump. The feed inlet of the separator is connected to a spray pipe, and the spray pipe is equipped with spray heads.

2. The high-salinity tailwater treatment system for chlorination towers according to claim 1, characterized in that, The outlet of the feed pump is connected to the material inlet of the feed preheater, the material outlet of the feed preheater is connected to the material inlet of the heat exchanger, and the material outlet of the heat exchanger is connected to the feed inlet of the separator.

3. The high-salinity tailwater treatment system for chlorination towers according to claim 1, characterized in that, The heat exchanger is a single-pass shell-and-tube heat exchanger; the compressor is a centrifugal compressor.

4. The high-salinity tailwater treatment system for chlorination towers according to any one of claims 1-3, characterized in that, The separator has a cylindrical structure and a sleeve inside. The spray pipe and spray head are located on the upper part of the sleeve. The diameter of the sleeve is not less than 2 / 3 of the diameter of the separator, and the height of the sleeve is 1 / 3 of the height of the separator.

5. The high-salinity tailwater treatment system of the chlorination tower according to claim 4, characterized in that, The separator has an inverted conical guide plate at the bottom, and the top of the guide plate is sealed to the inner wall of the separator. The bottom of the guide plate has a guide pipe, which is suspended in the lower part of the separator. There is a gap between the sleeve and the top of the guide plate, and the part below the guide plate is a crystallization chamber.

6. The high-salinity tailwater treatment system for chlorination towers according to claim 5, characterized in that, The circulation port is located on the side wall of the separator at the top of the crystallization chamber; the crystallization port is located at the bottom of the separator.

7. The high-salinity tailwater treatment system of the chlorination tower according to claim 4, characterized in that, There is a gap between the steam outlet at the top of the separator and the sleeve, and a wire mesh demister and a baffle plate demister are arranged sequentially from top to bottom.

8. The high-salinity tailwater treatment system for chlorination towers according to claim 5, characterized in that, The crystallization chamber is equipped with a level gauge and a temperature sensor, and the separator is also equipped with a pressure sensor.

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