NMP waste liquid rectification integrated device

Abstract

The application relates to the field of waste liquid treatment and rectification purification, in particular to a pry block integrated device for NMP waste liquid rectification. The pry block integrated device comprises a device pry block group and a rectification tower group, and the two groups jointly form a waste liquid pretreatment unit, an NMP continuous rectification unit, a rectification kettle residue treatment unit, a tail gas treatment unit and a product temporary storage unit. The units have clear division of labor, and can complete the pretreatment, rectification purification, rectification kettle residue treatment, tail gas treatment and product storage of NMP waste liquid. The device pry block group is composed of pry blocks with steel frame structures of different sizes, and is used for installing various pumps, kettles, condensers and other equipment. The rectification tower group comprises multiple rectification towers and a tail gas absorption tower. A preheating unit and a stairwell are further arranged. The pry block integrated device can realize the rectification purification of NMP waste liquid, can centrally treat tail gas generated by the units to make the tail gas meet the discharge standard, can discharge qualified residues, can store NMP products after rectification purification, and the pry block design is convenient for transportation and installation.

Description

Technical Field

[0001] This application relates to the field of waste liquid treatment and distillation purification, and in particular to a skid-mounted integrated distillation device for NMP waste liquid. Background Technology

[0002] Globally, the new energy vehicle industry is booming, and China's new energy vehicle industry has entered a new stage of strategic upgrading and globalization. The globalization of the lithium battery industry chain has become an inevitable trend. In lithium battery electrode preparation, NMP, as a solvent and diffusion liquid in the slurry, almost entirely needs to be evaporated and recycled after coating. Establishing a localized NMP closed-loop recycling system internalizes supply chain risks, which is a beneficial measure to ensure the stability and safety of raw materials at production bases, as well as reduce battery manufacturing costs and emissions. This initiative is of great significance for ensuring the stable production and sustainable development of lithium battery companies, effectively enhancing their competitiveness in the global market, and also helping to promote the lithium battery industry towards a more environmentally friendly and efficient direction, meeting the current societal demand for green energy and sustainable development.

[0003] In traditional NMP distillation unit construction, on-site construction and assembly are typically carried out overseas. This traditional approach involves installing and commissioning dynamic and static equipment, instrumentation, electrical systems, piping, fittings, valves, and other components individually on-site. This requires transporting a large number of these components to the overseas construction site. Furthermore, due to the lack of a complete and efficient supply chain in most countries, many spare parts may need to be airlifted from China, and the transportation of heavy equipment faces physical limitations such as roads, bridges, tunnels, and ports, requiring significant manpower and time to coordinate transportation and installation. In addition, overseas units must be designed to meet local standards, have higher material requirements, and require multiple certifications for equipment, all of which complicate and lengthy the construction process. Simultaneously, overseas construction also faces challenges such as differences in construction site conditions, the technical level of construction personnel, and stringent requirements for construction schedules. NMP distillation units, with their complex structure, contain various types of equipment and components. When constructing projects overseas, transporting large equipment using traditional methods may be limited by local transportation conditions. Furthermore, the precise connection and coordination between components during on-site installation can easily lead to installation errors. Traditional on-site installation and commissioning methods are not only time-consuming but also demand high levels of on-site expertise and skilled personnel. Installation errors during on-site installation can further extend the construction period, failing to meet the demands of overseas projects for time-saving and shortened construction cycles. Summary of the Invention

[0004] To achieve dual adaptability to road and sea transportation and shorten the overseas construction cycle of lithium battery companies, this application provides a skid-mounted NMP waste liquid distillation integrated device.

[0005] The integrated skid-mounted NMP waste liquid distillation device provided in this application adopts the following technical solution:

[0006] A skid-mounted NMP waste liquid distillation integrated device includes: a skid assembly and a distillation column assembly. The skid assembly and the distillation column assembly together constitute a waste liquid pretreatment unit, an NMP continuous distillation unit, a distillation kettle residue treatment unit, a tail gas treatment unit, and a finished product storage unit. The waste liquid pretreatment unit is used to receive and pretreat NMP waste liquid. The waste liquid pretreatment unit is connected to the NMP continuous distillation unit, which is used to purify the pretreated NMP waste liquid through NMP distillation. The NMP continuous distillation unit is connected to the distillation kettle residue treatment unit in one line and to the finished product temporary storage unit in the other line. The distillation kettle residue treatment unit is used to treat the distillation kettle residue and discharge qualified residue. The finished product temporary storage unit is used to store the NMP product after distillation and purification. The waste liquid pretreatment unit, the NMP continuous distillation unit, and the distillation kettle residue treatment unit are all connected to the tail gas treatment unit through tail gas pipelines. The tail gas treatment unit is used to collect the tail gas generated by each unit and perform centralized treatment to discharge qualified tail gas.

[0007] The equipment skid assembly includes skids M1, M2, M3, M4, M5, M6, M7, M8, and M9. Skids M1, M2, M3, M4, M5, M6, M7, and M8 each include a first steel frame structure with dimensions of 18m × 3.75m × 4.8m. Skid M9 includes a second steel frame structure with dimensions of 12.5m × 4.25m × 3.85m.

[0008] The distillation column group includes a first distillation column, a second distillation column, a third distillation column, and a tail gas absorption column. The NMP continuous distillation unit includes the first distillation column and the second distillation column. The distillation kettle residue treatment unit includes the third distillation column. The tail gas treatment unit includes the tail gas absorption column.

[0009] By adopting the above technical solution, this skid-mounted NMP waste liquid distillation integrated unit combines equipment skid groups and distillation column groups to form multiple functional units. It can realize functions such as waste liquid pretreatment, NMP distillation purification, distillation kettle residue treatment, tail gas treatment, and finished product temporary storage, producing electronic-grade NMP products that meet the reuse requirements of lithium battery companies. The equipment skid group adopts a skid-mounted design, with each skid having specific dimensions and specifications, facilitating pre-processing domestically and achieving dual adaptability to road and sea transportation. The integrated modules can be transported to ports by transport vehicles and then shipped overseas for on-site assembly, effectively shortening the overseas construction cycle for lithium battery companies. Simultaneously, the skid-mounted construction relies on excellent domestic construction resources and a complete material supply chain system, facilitating the assurance of construction and installation quality. It also allows for pre-assembly, pre-pressure testing, and pre-leak testing of modules domestically, fully ensuring the integrity of the unit's functions and the reliability of the equipment quality. In addition, the exhaust gas treatment unit centrally treats the exhaust gas generated by each unit, which can reduce the amount of waste gas, wastewater, and solid waste to an extremely low level, meet local emission standards, promote the recycling of NMP solvent in the lithium battery industry, and has great economic and environmental benefits.

[0010] Optionally, the waste liquid pretreatment unit includes a pretreatment vessel, a feed pump, and an additive pump. The raw material inlet of the pretreatment vessel is connected to an external NMP waste liquid conveying pipeline. The additive inlet of the pretreatment vessel is connected to the outlet of the additive pump. The feed end of the additive pump is connected to an external additive conveying pipeline. The outlet of the pretreatment vessel is connected to the feed end of the feed pump through a pipeline. The outlet of the feed pump is connected to the NMP continuous distillation unit.

[0011] By adopting the above technical solution, a pretreatment tank, a feed pump, and an additive pump are installed in the waste liquid pretreatment unit. External NMP waste liquid is transported to the pretreatment tank, and additives of specific components are added via the additive pump. Selecting suitable additive components allows for targeted treatment of impurities in the NMP waste liquid, causing them to undergo chemical reactions to form precipitates or alter their physical properties, facilitating subsequent separation. The additives can also adjust the pH, surface tension, and other properties of the waste liquid, optimizing the pretreatment effect and providing higher-quality raw materials for the subsequent continuous NMP distillation unit, thereby improving the separation efficiency and product quality of the entire integrated unit.

[0012] Optionally, the NMP continuous distillation unit includes a first distillation structure and a second distillation structure. The first distillation structure includes a first distillation column, a first reboiler pump, a first reboiler, a first reflux pump, a wastewater tank, a third reflux pump, a first condenser, and a first reflux tank. The second distillation structure includes a second distillation column, a second reboiler pump, a second reboiler, a second reflux pump, a second condenser, and a second reflux tank. The discharge end of the feed pump is connected to the feed inlet of the first distillation column. The bottom liquid phase outlet of the first distillation column is connected to the inlet of the first reboiler pump. The outlet of the first reboiler pump includes two paths, one of which passes through the first distillation column... A reboiler is connected to the bottom vapor inlet of the first distillation column. Another path of the outlet of the first column bottom pump is connected to the feed inlet of the second distillation column. The top vapor outlet of the first distillation column is connected to the inlet of the first condenser. The liquid outlet of the first condenser is connected to the inlet of the first reflux tank. The outlet of the first reflux tank is connected to the inlet of the first reflux pump. The outlet of the first reflux pump includes two paths. One path of the first reflux pump outlet is connected to the top reflux port of the first distillation column. The other path of the first reflux pump outlet is connected to the wastewater tank. The outlet of the wastewater tank is connected to the wastewater discharge port through the third reflux pump.

[0013] The bottom liquid outlet of the second distillation column is connected to the inlet of the second reboiler pump. The outlet of the second reboiler pump has two paths: one path is connected to the bottom vapor inlet of the second distillation column via the second reboiler, and the other path is connected to the distillation reboiler residue treatment unit. The top vapor outlet of the second distillation column is connected to the inlet of the second condenser. The liquid outlet of the second condenser is connected to the inlet of the second reflux tank. The outlet of the second reflux tank is connected to the inlet of the second reflux pump. The outlet of the second reflux pump has two paths: one path is connected to the top reflux port of the second distillation column, and the other path is connected to the feed inlet of the first distillation column. The middle side outlet of the second distillation column is connected to the finished product temporary storage unit.

[0014] By adopting the above technical solution, the first and second distillation structures of the NMP continuous distillation unit work together to efficiently purify the pretreated NMP waste liquid through distillation. The first distillation column performs preliminary separation of the feed. The vapor phase at the top of the column is partially refluxed after condensation to ensure the distillation effect, while the other part of the wastewater is discharged through a wastewater tank. The liquid phase at the bottom of the column is heated and vaporized by a reboiler and returned to the column, while the other part is sent to the second distillation column for further purification, thus achieving preliminary separation and wastewater discharge. The second distillation column performs secondary distillation on the material from the first distillation column. The liquid phase at the bottom of the column is circulated through a reboiler, while the other part is sent to the distillation vessel residue treatment unit for residue treatment. The vapor phase at the top of the column is partially refluxed after condensation, while the other part is returned to the first distillation column for re-distillation. The qualified NMP product collected from the middle side stream is sent to the finished product temporary storage unit, which improves the purity and recovery rate of NMP product and can produce electronic-grade NMP product that meets the reuse requirements of lithium battery companies. At the same time, it reduces the emission of waste gas, wastewater, and solid waste to an extremely low level, promotes the recycling of NMP solvent in the lithium battery industry, and has great economic and environmental benefits.

[0015] Optionally, the distillation kettle residue treatment unit further includes a distillation kettle, a third column reboiler pump, a third condenser, a fraction receiving tank, and a transfer pump. One of the outlets of the second column reboiler pump connected to the distillation kettle residue treatment unit is connected to the feed inlet of the distillation kettle. The bottom outlet of the distillation kettle is connected to the inlet of the third column reboiler pump. The outlet of the third column reboiler pump is used to connect to external storage equipment. The vapor phase outlet of the distillation kettle is connected to the third distillation column. The top vapor phase outlet of the third distillation column is connected to the inlet of the third condenser. The liquid phase outlet of the third condenser includes two paths. One path of the third condenser outlet is connected to the top reflux port of the third distillation column, and the other path of the third condenser outlet is connected to the fraction receiving tank. The outlet of the fraction receiving tank is connected to the feed inlet of the pretreatment kettle through the transfer pump.

[0016] By adopting the above technical solution, this distillation kettle residue treatment unit can effectively treat the distillation kettle residue generated by the continuous NMP distillation unit. The distillation kettle receives the residue discharged from the second distillation column, and further separates it through the third distillation column, allowing the recovery and reuse of useful components in the residue. The third condenser condenses the vapor phase at the top of the column, with one stream flowing back to the third distillation column to ensure distillation efficiency, and the other stream flowing into the fraction receiving tank. The fraction in the fraction receiving tank is transported back to the pretreatment kettle by a transfer pump to participate in the treatment process again, improving the NMP recovery rate. At the same time, qualified residue is discharged to external storage equipment through the third column kettle pump, achieving compliant discharge of residue and reducing waste generation. Overall, this distillation kettle residue treatment unit improves resource utilization, reduces production costs, is environmentally friendly, and promotes the recycling of NMP solvent.

[0017] Optionally, the exhaust gas treatment unit further includes a vacuum buffer tank, a vacuum pump, an exhaust gas buffer tank, a fan, a water tank, a water inlet pump, an absorption device, a circulation pump, and a first cooler. The gas phase outlets of the first condenser, the second condenser, and the third condenser are all connected to the inlet of the vacuum buffer tank. The outlet of the vacuum buffer tank is connected to the lower gas inlet of the exhaust gas absorption tower via the vacuum pump, the exhaust gas buffer tank, and the fan. The inlet of the water tank is connected to an external water supply pipeline. The outlet of the water tank is connected to the inlet of the water inlet pump. The outlet of the water inlet pump is connected to the upper liquid phase inlet of the exhaust gas absorption tower. The bottom liquid phase outlet of the exhaust gas absorption tower is connected to the inlet of the circulation pump. The outlet of the circulation pump includes two paths: one path of the circulation pump outlet is connected to the middle liquid phase inlet of the exhaust gas absorption tower via the first cooler, and the other path of the circulation pump outlet is connected to the raw material inlet of the pretreatment vessel.

[0018] By adopting the above technical solution, the exhaust gas treatment unit can effectively collect the gaseous exhaust gas discharged from the first condenser, second condenser, and third condenser. The gas pressure is stabilized by a vacuum buffer tank, and the exhaust gas is extracted by a vacuum pump. After further buffering in the exhaust gas buffer tank, it is sent to the exhaust gas absorption tower by a fan. A water tank provides absorption water to the exhaust gas absorption tower. A water pump delivers water to the upper part of the exhaust gas absorption tower, ensuring full contact and absorption with the exhaust gas entering from the lower part. The liquid phase at the bottom of the exhaust gas absorption tower is cooled by a circulating pump and returned to the middle for re-absorption. Another path returns to the raw material inlet of the pretreatment tank, achieving water resource recycling, improving exhaust gas treatment efficiency, reducing costs, and ensuring that the exhaust gas meets emission standards, thus reducing environmental pollution.

[0019] Optionally, the finished product storage unit includes a buffer tank, a side-sampling pump, a second cooler, a product inspection tank, a product pump, and a filter. The middle side-sampling outlet of the second distillation column is connected to the product inspection tank in sequence through the buffer tank, the side-sampling pump, and the second cooler. The outlet of the product inspection tank is connected to the inlet of the filter through the product pump. The outlet of the filter is used to connect to an external NMP product receiving pipeline.

[0020] By adopting the above technical solution, the finished product temporary storage unit utilizes a buffer tank, a side sampling pump, a second cooler, a product inspection tank, a product pump, and a filter to perform operations such as buffering, conveying, cooling, inspection, pumping, and filtering on the NMP product sampled from the side stream in the middle of the second distillation column. This ensures the quality of the NMP product and facilitates the delivery of qualified NMP product to the external NMP product receiving pipeline, thereby achieving effective storage and stable output of the NMP product after distillation and purification.

[0021] Optionally, a preheating unit is also included, the preheating unit comprising a preheater having a heat source medium channel and a medium to be heated channel, the inlet of the heat source medium channel being connected to the outlet of the side sampling pump, the outlet of the heat source medium channel being connected to the inlet of the second cooler, the inlet of the medium to be heated channel being connected to the outlet of the feed pump, and the outlet of the medium to be heated channel being connected to the feed inlet of the first distillation column.

[0022] By adopting the above technical solution, the preheating unit can utilize the heat of the material at the outlet of the side sampling pump to preheat the NMP waste liquid to be entered into the first distillation column, thereby improving energy utilization and reducing additional heating energy consumption; at the same time, it reduces the temperature of the material entering the second cooler, reduces the load on the second cooler, further saves energy, and improves the energy utilization efficiency and operating economy of the entire unit.

[0023] Optionally, the M1 skid and the M2 skid are detachably connected and arranged adjacent to each other in the horizontal direction. The M1 skid is used to install the first reboiler pump, the second reboiler pump, the third reboiler pump, the first reflux pump, the second reflux pump, the third reflux pump, and the blower. The M2 skid is used to install the water inlet pump, the feed pump, the additive pump, and the pretreatment vessel.

[0024] The M3 skid and the M4 skid are detachably connected and arranged adjacent to each other in the horizontal direction. The M3 skid is located above the M1 skid and is detachably connected to the M1 skid. The M4 skid is located above the M2 skid and is detachably connected to the M2 skid. The M3 skid is used to install the first reboiler, the second reboiler, the distillation kettle, the vacuum pump, and the tail gas buffer tank. The M4 skid is used to install the water tank, the transfer pump, and the circulation pump.

[0025] The M5 skid and the M6 ​​skid are detachably connected and arranged adjacent to each other in the horizontal direction. The M5 skid is located above the M3 skid and is detachably connected to the M3 skid. The M6 ​​skid is located above the M4 skid and is detachably connected to the M4 skid. The M5 skid is used to install the first reflux tank, the second reflux tank and the vacuum buffer tank. The M6 ​​skid is used to install the fraction receiving tank, the wastewater tank, the second cooler and the preheater.

[0026] The M7 skid and the M8 skid are detachably connected and arranged adjacent to each other in the horizontal direction. The M7 skid is located above the M5 skid and is detachably connected to the M5 skid. The M8 skid is located above the M6 ​​skid and is detachably connected to the M6 ​​skid. The M7 skid is used to install the first condenser, the second condenser and the absorption device. The M8 skid is used to install the third condenser and the first cooler.

[0027] The M9 skid is located on the side of the M2 skid away from the M1 skid, and the M9 skid is used to house the buffer tank, the side sampling pump, the product inspection tank, the product pump, and the filter.

[0028] By adopting the above technical solution, the various devices are rationally distributed across different skids and detachably connected, facilitating transportation and on-site assembly, and shortening the overseas construction cycle for lithium battery companies. Each skid has a clearly defined function: skid M1 houses multiple pumps and fans; skid M2 houses inlet pumps, feed pumps, additive pumps, and a pretreatment vessel, facilitating waste liquid pretreatment and transportation; skid M3 houses a reboiler, distillation vessel, vacuum pump, and tail gas buffer tank; skid M4 houses a water tank, transfer pump, and circulation pump, ensuring the distillation and tail gas treatment processes; skid M5 houses a reflux tank and vacuum buffer tank; skid M6 houses a fraction receiving tank, wastewater tank, cooler, and preheater, aiding in distillation purification and heat recovery; skid M7 houses a condenser and absorption device; skid M8 houses a third condenser and a first cooler, ensuring tail gas treatment and heat exchange; and skid M9 houses a buffer tank, side sampling pump, product inspection tank, product pump, and filter, realizing the storage and filtration of NMP products after distillation purification. The entire device is fully functional and can produce electronic-grade NMP products that can be reused by lithium battery companies, reducing the amount of waste, promoting the recycling of NMP solvents, and having significant economic and environmental benefits.

[0029] Optionally, the distillation column assembly is located on the side of skid M1 away from skid M2.

[0030] By adopting the above technical solution, the distillation column group is set on the side of skid M1 away from skid M2. This allows for a reasonable layout of the equipment, avoids mutual interference between equipment, and facilitates the installation, maintenance and repair of the equipment. At the same time, it makes the arrangement of connecting pipelines between units more reasonable, reduces pipeline length and resistance, and lowers construction and operating costs.

[0031] Optionally, it also includes two stairwells, which are respectively located at both ends of the equipment skid assembly, and the dimensions of each stairwell are 14.1m × 4m × 2.5m.

[0032] By adopting the above technical solution, two stairwells with dimensions of 14.1m×4m×2.5m are set at both ends of the equipment skid assembly to facilitate operators' access to various parts of the device for operation, maintenance and repair. Combined with other structures of the skid-mounted NMP waste liquid distillation integrated device, the entire device can have functions such as waste liquid pretreatment, NMP distillation purification, distillation kettle residue treatment, tail gas treatment and finished product temporary storage, producing electronic-grade NMP products that can be reused by lithium battery companies, reducing the amount of waste gas, wastewater, and solid waste, achieving dual adaptability to road and sea transportation, shortening the overseas construction cycle of lithium battery companies, and ensuring the quality of construction and installation, the integrity of device functions and the reliability of equipment quality.

[0033] In summary, this application includes at least one of the following beneficial technical effects:

[0034] 1. Achieve dual adaptability of road transportation and sea transportation, shorten the overseas construction cycle of lithium battery companies, and solve the problem of long construction cycles caused by factors such as limited land and sea transportation space, insufficient material supply, difficulty in coordinating human resources, and harsh construction environment in overseas construction.

[0035] 2. The integrated module has complete functions, which can realize functions such as waste liquid pretreatment, NMP distillation purification, distillation kettle residue treatment, tail gas treatment, and finished product temporary storage. It produces electronic-grade NMP products that meet the needs of lithium battery companies for reuse, while reducing the emission of waste gas, wastewater, and solid waste to an extremely low level, promoting the recycling of NMP solvents in the lithium battery industry, and has great economic and environmental benefits.

[0036] 3. The skid-mounted construction relies on excellent domestic construction resources and a complete material supply chain system, which facilitates the assurance of construction and installation quality. Furthermore, the modules can undergo pre-assembly, pre-pressure testing, and pre-leak testing in China, fully ensuring the integrity of the device's functions and the reliability of the equipment quality. Attached Figure Description

[0037] Figure 1 This is a simplified structural diagram of the skid-mounted NMP waste liquid distillation integrated device provided in the embodiments of this application.

[0038] Figure 2 This is a simplified process flow diagram of the skid-mounted NMP waste liquid distillation integrated device provided in the embodiments of this application.

[0039] Explanation of reference numerals in the attached drawings: 1-Pretreatment vessel; 2-Feed pump; 3-Auxiliary agent pump; 4-First distillation column; 5-First column bottom pump; 6-First reboiler; 7-First reflux pump; 8-Wastewater tank; 9-Third reflux pump; 10-First condenser; 11-First reflux tank; 12-Second distillation column; 13-Second column bottom pump; 14-Second reboiler; 15-Second reflux pump; 16-Second condenser; 17-Second reflux tank; 18-Third distillation column; 19-Distillation vessel; 20-Third column bottom pump; 21-Third condenser; 22-Fraction receiving tank; 23-Transfer pump; 24-Tail gas absorber Tower; 25-Vacuum buffer tank; 26-Vacuum pump; 27-Emergency gas buffer tank; 28-Fan; 29-Water tank; 30-Inlet pump; 31-Absorption device; 32-Circulation pump; 33-First cooler; 34-Buffer tank; 35-Side sampling pump; 36-Second cooler; 37-Product inspection tank; 38-Product pump; 39-Filter; 40-Preheater; 41-M1 skid; 42-M2 skid; 43-M3 skid; 44-M4 skid; 45-M5 skid; 46-M6 skid; 47-M7 skid; 48-M8 skid; 49-M9 skid; 50-Stairwell. Detailed Implementation

[0040] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0041] This application discloses a skid-mounted NMP waste liquid distillation integrated device.

[0042] like Figure 1 and Figure 2 As shown, the skid-mounted NMP waste liquid distillation integrated device includes a skid assembly and a distillation column assembly. The skid assembly and the distillation column assembly together constitute a waste liquid pretreatment unit, an NMP continuous distillation unit, a distillation kettle residue treatment unit, a tail gas treatment unit, and a finished product temporary storage unit. It realizes the full-process function of NMP waste liquid from pretreatment to distillation purification, residue treatment and product storage, as well as tail gas treatment, thereby improving the NMP recycling rate and reducing the emission of waste gas, wastewater, and solid waste.

[0043] Specifically, the equipment skid assembly includes skid 41 (M1), skid 42 (M2), skid 43 (M3), skid 44 (M4), skid 45 (M5), skid 46 (M6), skid 47 (M7), skid 48 (M8), and skid 49 (M9). Skids 41, 42, 43, 44, 45, 46, 47, and 48 all include a first steel frame structure, which can be welded from high-strength steel and has dimensions of 18m × 3.75m × 4.8m. This standardized steel frame structure facilitates skid-mounted production and transportation. Alternatively, an aluminum alloy frame structure can be used to reduce weight. Skid 49 includes a second steel frame structure with dimensions of 12.5m × 4.25m × 3.85m.

[0044] like Figure 1 and Figure 2 As shown, skid M1 41 and skid M2 42 are detachably connected and arranged adjacent to each other in the horizontal direction. Skid M1 41 is used to install the first reboiler pump 5, the second reboiler pump 13, the third reboiler pump 20, the first reflux pump 7, the second reflux pump 15, the third reflux pump 9, and the blower 28. These pumps are generally centrifugal pumps, which are characterized by large flow rate and high head. Alternatively, screw pumps can be used, which are suitable for conveying high-viscosity liquids. The pump body is usually made of cast iron or stainless steel to ensure corrosion resistance. The pumps are fixed to the steel frame structure of skid M1 41 by anchor bolts and connected to the pipeline through flanges to ensure the sealing and stability of the connection. The blower 28 can be a centrifugal blower, which is mounted on skid M1 41 by a bracket and connected to the pipeline for gas transportation.

[0045] The M2 skid 42 is used to house the inlet pump 30, feed pump 2, additive pump 3, and pretreatment vessel 1. The inlet pump 30, feed pump 2, and additive pump 3 can also be centrifugal pumps. The pretreatment vessel 1 is generally a cylindrical tank made of stainless steel, offering good corrosion resistance. The top of the pretreatment vessel 1 has inlet ports; one inlet connects to the external waste liquid inlet pipeline of the module, and the other inlet connects to the additive pump 3. The tank is equipped with measuring instruments for temperature, pressure, and liquid level, and the additive addition rate is controlled by these instrument readings. The bottom outlet pipe of the pretreatment vessel 1 is connected to the inlet of feed pump 2 via a flange, and the outlet pipe of feed pump 2 is connected to the NMP continuous distillation unit.

[0046] Skid 43 and skid 44 are detachably connected and arranged adjacent to each other in the horizontal direction. Skid 43 is located above and detachably connected to skid 41, and skid 44 is located above and detachably connected to skid 42. Skid 43 is used to install the first reboiler 6, the second reboiler 14, the distillation vessel 19, the vacuum pump 26, and the tail gas buffer tank 27. The reboiler can be a horizontal thermosiphon reboiler, which consists of a shell, tube bundle, tube sheet, etc., and heats and vaporizes the liquid through heat exchange. The distillation vessel 19 is a tank with a heating device, used for further distillation of the material. The vacuum pump 26 is a water ring vacuum pump, which is connected to the equipment through pipelines to create a vacuum environment. The tail gas buffer tank 27 is a cylindrical tank used to buffer the tail gas pressure. These devices are fixed to the steel frame structure of skid 43 by brackets and bolts.

[0047] M4 skid 44 is used to install water tank 29, transfer pump 23, and circulation pump 32. Water tank 29 is a container for storing water, typically made of plastic or stainless steel. Transfer pump 23 and circulation pump 32 are centrifugal pumps, connected to other equipment via pipelines to achieve material transfer and circulation.

[0048] Skid 45 and skid 46 are detachably connected and arranged adjacent to each other in the horizontal direction. Skid 45 is located above and detachably connected to skid 43, and skid 46 is located above and detachably connected to skid 44. Skid 45 is used to install the first reflux tank 11, the second reflux tank 17, and the vacuum buffer tank 25. The reflux tank is a cylindrical tank used to collect reflux liquid. The vacuum buffer tank 25 is also a cylindrical tank used to buffer vacuum pressure. These tanks are fixed to skid 45 by brackets and bolts.

[0049] The M6 ​​skid 46 is used to house the fraction receiving tank 22, wastewater tank 8, secondary cooler 36, and preheater 40. The fraction receiving tank 22 and wastewater tank 8 are containers made of stainless steel for storing different fractions and wastewater. The secondary cooler 36 can be a shell-and-tube cooler, using cooling water to cool the materials. The preheater 40 has a heat source medium passage and a medium to be heated passage for preheating the materials. These devices are connected to other equipment via pipes and supports.

[0050] Skid 47 and skid 48 are detachably connected and arranged adjacent to each other in the horizontal direction. Skid 47 is located above and detachably connected to skid 45, and skid 48 is located above and detachably connected to skid 46. Skid 47 is used to install the first condenser 10, the second condenser 16, and the absorption device 31. The condensers are shell-and-tube condensers, which condense the gas phase into the liquid phase using cooling water. The absorption device 31 can be a packed tower, which absorbs and treats the exhaust gas through the packing. These devices are installed on skid 47 via pipes and supports.

[0051] The M8 skid 48 is used to install the third condenser 21 and the first cooler 33. The third condenser 21 is also a shell-and-tube condenser, and the first cooler 33 is a shell-and-tube cooler. They are connected to other equipment through pipes to achieve cooling of materials.

[0052] Skid M9 49 is located on the side of Skid M2 42 away from Skid M1 41. Skid M9 49 is used to house the buffer tank 34, side sampling pump 35, product inspection tank 37, product pump 38, and filter 39. The buffer tank 34 is a container for storing materials. The side sampling pump 35 and product pump 38 are centrifugal pumps. The product inspection tank 37 is a tank for storing products to be tested. The filter 39 is a cartridge filter used to filter impurities from the product. These devices are connected together via pipes and supports. The skid-mounted design of this application, by completing the pre-installation and testing of most of the equipment and piping domestically, fundamentally avoids the accuracy problems that may occur during overseas on-site installation, ensuring the integrity and reliability of the device.

[0053] like Figure 2 As shown, the distillation column group includes a first distillation column 4, a second distillation column 12, a third distillation column 18, and a tail gas absorption column 24. The first distillation column 4 and the second distillation column 12 are used for NMP distillation purification of the pretreated NMP waste liquid. The third distillation column 18 is used for residue treatment in the distillation kettle 19. The tail gas absorption column 24 is used to collect the tail gas generated by each unit and perform centralized treatment. The distillation columns are generally cylindrical, with internal trays or packing to increase the gas-liquid contact area and improve distillation efficiency. The column body is made of stainless steel, providing good corrosion resistance. The column body is fixed to the ground with foundation bolts and connected to other equipment via pipelines.

[0054] The combination logic and effect of the various skids and distillation columns in this embodiment lies in the fact that, through reasonable layout and connection, the transfer of materials and energy between units is smoother. For example, through pipeline connections, continuous production of NMP waste liquid is achieved from pretreatment to distillation purification, then to residue treatment and product storage. Simultaneously, the skid-mounted design of each skid facilitates prefabrication and pre-assembly in China, requiring only on-site assembly during overseas construction, significantly shortening the construction cycle. Moreover, this layout also facilitates equipment inspection and maintenance, improving the service life and reliability of the unit.

[0055] The implementation principle of the skid-mounted NMP waste liquid distillation integrated device in this application is as follows:

[0056] 1. Waste Liquid Pretreatment: NMP waste liquid is transported to the raw material inlet of pretreatment vessel 1 through an external pipeline. Additive pump 3 delivers external additives into pretreatment vessel 1, and the amount of additives added is controlled according to the temperature, pressure, and liquid level readings on pretreatment vessel 1. The pretreated NMP waste liquid is then transported from the bottom outlet of pretreatment vessel 1 through a pipeline to feed pump 2, and then from feed pump 2 to the NMP continuous distillation unit.

[0057] 2. Continuous distillation of NMP:

[0058] The first distillation structure: NMP waste liquid delivered by feed pump 2 enters the first distillation column 4. The liquid phase at the bottom of the first distillation column 4 is transported by the first reboiler pump 5. One path is heated by the first reboiler 6 and returned to the bottom of the first distillation column 4 as a vapor phase, while the other path is transported to the second distillation column 12. The vapor phase at the top of the first distillation column 4 enters the first condenser 10 and is condensed into a liquid phase, then flows into the first reflux tank 11. The liquid in the first reflux tank 11 is transported by the first reflux pump 7. One path is returned to the top of the first distillation column 4, while the other path is transported to the wastewater tank 8. The wastewater in the wastewater tank 8 is discharged to the wastewater discharge port by the third reflux pump 9.

[0059] The second distillation structure: The liquid phase at the bottom of the second distillation column 12 is transported by the second reboiler pump 13. One path is heated by the second reboiler 14 and returned to the bottom of the second distillation column 12 as a vapor phase. The other path is transported to the distillation reboiler residue treatment unit. The vapor phase at the top of the second distillation column 12 enters the second condenser 16 and is condensed into a liquid phase before flowing into the second reflux tank 17. The liquid in the second reflux tank 17 is transported by the second reflux pump 15. One path is returned to the top of the second distillation column 12, and the other path is transported to the feed inlet of the first distillation column 4. The material collected from the side stream in the middle of the second distillation column 12 is transported to the finished product temporary storage unit.

[0060] 3. Residue treatment in distillation kettle 19: The material delivered by the second column reboiler pump 13 enters the distillation kettle 19. The residue at the bottom of the distillation kettle 19 is transported to an external container by the third column reboiler pump 20. The vapor phase from the distillation kettle 19 enters the third distillation column 18. The vapor phase at the top of the third distillation column 18 enters the third condenser 21 for condensation. One stream flows back to the top of the third distillation column 18, and the other stream flows into the fraction receiving tank 22. The liquid in the fraction receiving tank 22 is transported to the feed inlet of the pretreatment kettle 1 by the transfer pump 23.

[0061] 4. Exhaust Gas Treatment: The gaseous exhaust gases from the outlets of the first condenser 10, the second condenser 16, and the third condenser 21 are all transported to the vacuum buffer tank 25, and then sequentially transported to the lower part of the exhaust gas absorption tower 24 via the vacuum pump 26, the exhaust gas buffer tank 27, and the fan 28. Water in the water tank 29 is transported to the upper part of the exhaust gas absorption tower 24 via the inlet pump 30. The liquid phase at the bottom of the exhaust gas absorption tower 24 is transported by the circulating pump 32, with one path passing through the first cooler 33 for cooling and returning to the middle of the exhaust gas absorption tower 24, and the other path being transported to the raw material inlet of the pretreatment vessel 1. The exhaust gas at the top of the exhaust gas absorption tower 24, after being treated by the absorption device 31, meets the emission standards and is then discharged.

[0062] 5. Finished Product Temporary Storage: The material extracted from the side stream in the middle of the second distillation column 12 is sequentially transported to the heat source medium channel of the preheater 40 via the buffer tank 34 and the side extraction pump 35 for heat exchange. After further cooling by the second cooler 36, it enters the product inspection tank 37. The product in the product inspection tank 37 is transported to the filter 39 via the product pump 38 for filtration, and finally transported to the external NMP product receiving pipeline through the outlet of the filter 39.

[0063] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A skid-mounted NMP waste liquid distillation integrated device, characterized in that, include: The equipment skid assembly and the distillation column assembly constitute a waste liquid pretreatment unit, an NMP continuous distillation unit, a distillation kettle residue treatment unit, a tail gas treatment unit, and a finished product temporary storage unit. The waste liquid pretreatment unit is used to receive NMP waste liquid and pretreat it. The waste liquid pretreatment unit includes a pretreatment tank (1), a feed pump (2), and an additive pump (3). The waste liquid pretreatment unit is connected to the NMP continuous distillation unit, which is used to purify the pretreated NMP waste liquid through NMP distillation. The NMP continuous distillation unit is connected in two ways: one to the distillation kettle residue treatment unit and the other to the finished product storage unit. The distillation kettle residue treatment unit is used to treat the residue from the distillation kettle (19) and discharge qualified residue. The finished product storage unit is used to store the NMP product after distillation and purification. The waste liquid pretreatment unit, the NMP continuous distillation unit, and the distillation kettle residue treatment unit are all connected to the tail gas treatment unit through tail gas pipelines. The tail gas treatment unit is used to collect the tail gas generated by each unit and perform centralized treatment to discharge tail gas that meets the standards. The equipment skid assembly includes skid M1 (41), skid M2 (42), skid M3 (43), skid M4 (44), skid M5 (45), skid M6 (46), skid M7 (47), skid M8 (48), and skid M9 (49). Skid M1 (41), skid M2 (42), skid M3 (43), skid M4 (44), skid M5 (45), skid M6 (46), skid M7 (47), and skid M8 (48) all include a first steel frame structure with dimensions of 18m × 3.75m × 4.8m. Skid M9 includes a second steel frame structure with dimensions of 12.5m × 4.25m × 3.85m. The distillation column group includes a first distillation column (4), a second distillation column (12), a third distillation column (18), and a tail gas absorption column (24). The NMP continuous distillation unit includes the first distillation column (4) and the second distillation column (12). The distillation vessel residue treatment unit includes the third distillation column (18). The tail gas treatment unit includes the tail gas absorption column (24). The NMP continuous distillation unit includes a first distillation structure and a second distillation structure. The first distillation structure includes a first distillation column (4), a first reboiler pump (5), a first reboiler (6), a first reflux pump (7), a wastewater tank (8), a third reflux pump (9), a first condenser (10), and a first reflux tank (11). The second distillation structure includes a second distillation column (12), a second reboiler pump (13), a second reboiler (14), a second reflux pump (15), a second condenser (16), and a second reflux tank (17). The discharge end of the feed pump (2) is connected to the feed inlet of the first distillation column (4). The bottom liquid outlet of the first distillation column (4) is connected to the inlet of the first reboiler pump (5). The outlet of the first reboiler pump (5) includes two paths. One path of the outlet of the first reboiler pump (5) is connected to the bottom gas inlet of the first distillation column (4) through the first reboiler (6). The other path of the outlet of the first reboiler pump (5) is connected to the feed inlet of the second distillation column (12). The top gas outlet of the first distillation column (4) is connected to the first condenser. The inlet of the first condenser (10) is connected to the liquid phase outlet of the first condenser (10) and the inlet of the first reflux tank (11). The outlet of the first reflux tank (11) is connected to the inlet of the first reflux pump (7). The outlet of the first reflux pump (7) includes two paths. One path of the outlet of the first reflux pump (7) is connected to the top reflux port of the first distillation column (4), and the other path of the outlet of the first reflux pump (7) is connected to the wastewater tank (8). The outlet of the wastewater tank (8) is connected to the wastewater discharge port through the third reflux pump (9). The bottom liquid outlet of the second distillation column (12) is connected to the inlet of the second reboiler pump (13). The outlet of the second reboiler pump (13) includes two paths. One path of the outlet of the second reboiler pump (13) is connected to the bottom gas inlet of the second distillation column (12) through the second reboiler (14). The other path of the outlet of the second reboiler pump (13) is connected to the distillation reboiler residue treatment unit. The top gas outlet of the second distillation column (12) is connected to the inlet of the second condenser (16). The liquid phase outlet of (16) is connected to the inlet of the second reflux tank (17), the outlet of the second reflux tank (17) is connected to the inlet of the second reflux pump (15), the outlet of the second reflux pump (15) includes two paths, one path of the outlet of the second reflux pump (15) is connected to the top reflux port of the second distillation column (12), the other path of the outlet of the second reflux pump (15) is connected to the feed port of the first distillation column (4), and the middle side line outlet of the second distillation column (12) is connected to the finished product temporary storage unit.

2. The integrated skid-mounted NMP waste liquid distillation device according to claim 1, characterized in that, The raw material inlet of the pretreatment vessel (1) is used to connect to an external NMP waste liquid conveying pipeline. The auxiliary agent inlet of the pretreatment vessel (1) is connected to the discharge end of the auxiliary agent pump (3). The feed end of the auxiliary agent pump (3) is used to connect to an external auxiliary agent conveying pipeline. The discharge end of the pretreatment vessel (1) is connected to the feed end of the feed pump (2) through a pipeline. The discharge end of the feed pump (2) is connected to the NMP continuous distillation unit.

3. The integrated skid-mounted NMP waste liquid distillation device according to claim 1, characterized in that, The distillation kettle residue treatment unit also includes a distillation kettle (19), a third column kettle pump (20), a third condenser (21), a fraction receiving tank (22), and a transfer pump (23). One of the outlets of the second column reboiler pump (13) connected to the distillation kettle residue treatment unit is connected to the feed inlet of the distillation kettle (19). The bottom outlet of the distillation kettle (19) is connected to the inlet of the third column reboiler pump (20). The outlet of the third column reboiler pump (20) is used to connect to external storage equipment. The vapor outlet of the distillation kettle (19) is connected to the third distillation column (18). The top vapor outlet of the third distillation column (18) is connected to the inlet of the third condenser (21). The liquid outlet of the third condenser (21) includes two paths. One path of the outlet of the third condenser (21) is connected to the top reflux port of the third distillation column (18). The other path of the outlet of the third condenser (21) is connected to the fraction receiving tank (22). The outlet of the fraction receiving tank (22) is connected to the raw material inlet of the pretreatment kettle (1) through the transfer pump (23).

4. The integrated skid-mounted NMP waste liquid distillation device according to claim 3, characterized in that, The exhaust gas treatment unit also includes a vacuum buffer tank (25), a vacuum pump (26), an exhaust gas buffer tank (27), a fan (28), a water tank (29), a water inlet pump (30), an absorption device (31), a circulation pump (32), and a first cooler (33). The gas phase outlets of the first condenser (10), the second condenser (16), and the third condenser (21) are all connected to the inlet of the vacuum buffer tank (25). The outlet of the vacuum buffer tank (25) is connected to the lower gas inlet of the tail gas absorption tower (24) via the vacuum pump (26), the tail gas buffer tank (27), and the fan (28) in sequence. The inlet of the water tank (29) is used to connect to an external water supply pipeline, and the outlet of the water tank (29) is connected to the inlet of the water pump (30). The outlet of the water inlet pump (30) is connected to the upper liquid phase inlet of the tail gas absorption tower (24), and the bottom liquid phase outlet of the tail gas absorption tower (24) is connected to the inlet of the circulating pump (32). The outlet of the circulating pump (32) includes two paths. One path of the outlet of the circulating pump (32) is connected to the middle liquid phase inlet of the tail gas absorption tower (24) through the first cooler (33), and the other path of the outlet of the circulating pump (32) is connected to the raw material inlet of the pretreatment vessel (1).

5. The integrated skid-mounted NMP waste liquid distillation device according to claim 4, characterized in that, The finished product temporary storage unit includes a buffer tank (34), a side sampling pump (35), a second cooler (36), a product inspection tank (37), a product pump (38), and a filter (39). The middle side-stream outlet of the second distillation column (12) is connected to the product inspection tank (37) in sequence through the buffer tank (34), the side-stream pump (35), and the second cooler (36). The outlet of the product inspection tank (37) is connected to the inlet of the filter (39) through the product pump (38). The outlet of the filter (39) is used to connect to the external NMP product receiving pipeline.

6. The integrated skid-mounted NMP waste liquid distillation device according to claim 5, characterized in that, It also includes a preheating unit, which includes a preheater (40) having a heat source medium channel and a medium to be heated channel. The inlet of the heat source medium channel is connected to the outlet of the side sampling pump (35), the outlet of the heat source medium channel is connected to the inlet of the second cooler (36), the inlet of the medium to be heated channel is connected to the outlet of the feed pump (2), and the outlet of the medium to be heated channel is connected to the feed port of the first distillation column (4).

7. The integrated skid-mounted NMP waste liquid distillation device according to claim 6, characterized in that, The M1 skid block (41) and the M2 skid block (42) are detachably connected and arranged adjacent to each other in the horizontal direction. The M1 skid (41) is used to install the first reboiler pump (5), the second reboiler pump (13), the third reboiler pump (20), the first reflux pump (7), the second reflux pump (15), the third reflux pump (9), and the blower (28). The M2 skid (42) is used to install the water inlet pump (30), the feed pump (2), the additive pump (3) and the pretreatment tank (1); The M3 pry bar (43) and the M4 pry bar (44) are detachably connected and arranged adjacent to each other in the horizontal direction. The M3 pry bar (43) is located above the M1 pry bar (41) and is detachably connected to the M1 pry bar (41). The M4 pry bar (44) is located above the M2 pry bar (42) and is detachably connected to the M2 pry bar (42). The M3 skid (43) is used to install the first reboiler (6), the second reboiler (14), the distillation vessel (19), the vacuum pump (26), and the tail gas buffer tank (27). The M4 skid (44) is used to install the water tank (29), the transfer pump (23), and the circulation pump (32); The M5 pry bar (45) and the M6 ​​pry bar (46) are detachably connected and arranged adjacent to each other in the horizontal direction. The M5 pry bar (45) is located above the M3 pry bar (43) and is detachably connected to the M3 pry bar (43). The M6 ​​pry bar (46) is located above the M4 pry bar (44) and is detachably connected to the M4 pry bar (44). The M5 skid (45) is used to set up the first reflux tank (11), the second reflux tank (17), and the vacuum buffer tank (25). The M6 ​​skid (46) is used to install the fraction receiving tank (22), the wastewater tank (8), the second cooler (36) and the preheater (40); The M7 pry bar (47) and the M8 pry bar (48) are detachably connected and arranged adjacent to each other in the horizontal direction. The M7 pry bar (47) is located above the M5 pry bar (45) and is detachably connected to the M5 pry bar (45). The M8 pry bar (48) is located above the M6 ​​pry bar (46) and is detachably connected to the M6 ​​pry bar (46). The M7 skid (47) is used to install the first condenser (10), the second condenser (16), and the absorption device (31). The M8 skid (48) is used to mount the third condenser (21) and the first cooler (33); The M9 skid (49) is located on the side of the M2 skid (42) away from the M1 skid (41). The M9 skid (49) is used to install the buffer tank (34), the side sampling pump (35), the product inspection tank (37), the product pump (38), and the filter (39).

8. The integrated skid-mounted NMP waste liquid distillation device according to claim 7, characterized in that, The distillation column assembly is located on the side of the M1 skid (41) away from the M2 skid (42).

9. The integrated skid-mounted NMP waste liquid distillation device according to claim 7, characterized in that, It also includes two stairwells (50), which are respectively located at both ends of the equipment skid assembly. The dimensions of each stairwell (50) are 14.1m × 4m × 2.5m.

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