Small molecule collecting device for nylon polymer devolatilization
By designing small molecule condenser and vacuum collection tank system, using multi-stage condensation effect and "U" font gas path design, the problem of collecting small molecules in nylon 6 polymers is solved, and efficient and environmentally friendly nylon fiber production is achieved .
Patent Information
- Application Number
- CN202420471929.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-12
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-03-12
AI Technical Summary
The prior art is difficult to effectively remove oligomers with high boiling points in the nylon 6 polymer melt, and the traditional condensation collection system is prone to blockage, which cannot adapt to the sublimation and condensation phase transition process of nylon 6.
A small molecule condenser and vacuum collection tank system was designed to use the multi-stage condensation effect of high-temperature mixed steam to condense and collect small molecules at high boiling point. The inner wall of the condenser is designed through the "U" font gas path design and non-stick treatment. , avoid clogging and improve collection efficiency.
It realizes efficient devolatilization and collection of nylon 6 and its copolymer small molecules, avoids equipment blockage, simplifies process flow, reduces production costs, and reduces environmental pollution through exhaust gas treatment systems.
Smart Images
Figure CN222427152U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of nylon materials, in particular to a small molecule collection device for devolatilization of nylon polymers. Background Art
[0002] Nylon materials are widely used due to their excellent wear resistance, excellent mechanical strength and good corrosion resistance. Common nylon materials include nylon 6, nylon 66, nylon 56, etc., of which nylon 6 accounts for about 90% of the total nylon and is mainly used in civil fibers and engineering plastics. The hydrolysis ring-opening polymerization reaction of nylon 6 is a reversible reaction with a conversion rate of only about 90%. After the reaction, there are still about 10% of small molecules, namely caprolactam monomers and oligomers. These small molecules are free in the polymer melt in the form of impurities, which seriously affects the spinning process of nylon 6. At present, the industry adopts a hot water continuous extraction process. After the polymer is cooled into slices, the small molecules in the slices are extracted with hot water, so that the hot water extractable content of the slices reaches the standard of superior products and meets the subsequent spinning requirements. However, a large amount of water, energy and time costs are consumed in the extraction process and subsequent drying, remelting and other stages, which increases production costs and carbon emissions, and limits the further development of nylon fibers. Therefore, the realization of melt direct spinning of nylon fibers has great economic value and social benefits. First, the problem of high content of small molecules in nylon 6 polymer melt must be solved, and devolatilization under vacuum conditions is one of the ways. Currently, various industrial devolatilization equipment uses the reduction of small molecules' boiling point under high vacuum to remove small molecules from the system. At the same time, compared with traditional hot water extraction processes, there is no need for separation, cracking, purification, etc. However, the melting point of small molecule oligomers in nylon polymers is generally high, which can easily clog the condensation collection device of the vacuum system, requiring frequent switching and cleaning of the vacuum collection system.
[0003] At present, the condensation collection systems in the industry all use the difference in boiling points of substances for separation, but the oligomer components of nylon 6 polymer have a high melting point, among which the cyclic dimer has a melting point of up to 345°C. In addition, according to the current technology, its phase change process does not involve vaporization, but sublimation and condensation. Therefore, the traditional condensation collection system is not suitable for the small molecule collection process after nylon 6 devolatilization.
[0004] CN215841705U discloses a devolatilization device for polymer melt before spinning, comprising: a housing, an upper sealing plate covering the opening at the top of the housing, a melt feed pipe arranged on the upper sealing plate, and a devolatilization distribution plate arranged in the housing, which has the advantages of uniform material distribution and heat transfer, uniform and stable reaction, high efficiency, high production stability, low energy consumption, etc. However, there are problems that it can only devolatilize nylon 6 single melt, has a small application range, and does not process the residual gas.
[0005] Therefore, it is a problem that needs to be solved at present to find a small molecule collection device for nylon polymer devolatilization, which is not easy to clog the collection device and can treat the tail gas. Utility Model Content
[0006] The utility model aims to provide a small molecule collecting device for nylon polymer devolatilization, in which the collecting device is not easily blocked and can process tail gas.
[0007] The above technical problems are solved by the following technical solutions: a small molecule condenser and a vacuum collection tank connected to the bottom of the small molecule condenser through a pipeline, a baffle is provided inside the small molecule condenser, and the small molecule condenser is connected to the non-condensable gas treatment system through a pipeline, and the non-condensable gas treatment system includes a vacuum buffer tank, a vacuum system and an exhaust gas treatment system connected in sequence. The high-temperature mixed steam enters the small molecule condenser, and the high-temperature mixed steam is blocked by the baffle provided inside the small molecule condenser to move downward, and heat is exchanged in the small molecule condenser. After moving downward, the high-temperature mixed steam moves upward again, and heat is exchanged with the small molecule condenser again, so as to achieve the multi-stage condensation effect of a single device, and the condensed and bonded high-boiling point components flow into the vacuum collection tank, and the non-condensable gas that cannot be condensed is cooled to room temperature through the vacuum buffer tank, and is sucked into the water ring pump of the exhaust gas treatment system through the vacuum system, and the water-soluble gas in the gas phase is absorbed by water, and the wastewater flows into the waste liquid tank through the liquid phase outlet to prevent its toxic and harmful gases from being directly discharged into the atmosphere and polluting the environment, and the remaining gases are discharged into the atmosphere through the gas phase outlet.
[0008] Preferably, the small molecule condenser is composed of an upper head, a shell-and-tube heat exchanger and a lower head, wherein the upper end of the shell-and-tube heat exchanger is connected to the upper head, and the lower end is connected to the lower head.
[0009] Preferably, a condenser gas phase inlet and a condenser gas phase outlet are provided on the upper head, and the condenser gas phase inlet and the condenser gas phase outlet are arranged on two opposite sides of the upper head.
[0010] As a preferred method, a baffle is placed in the middle of the upper head, with the direction perpendicular to the bottom of the upper cover and passing through the center of the circle at the bottom of the upper head. The baffle evenly divides the upper head into two parts, and the small molecule condenser forms a "U"-shaped gas path. The high-temperature steam entering from the gas phase inlet of the condenser enters the shell-and-tube heat exchanger for graded condensation, so that the mixed steam is condensed twice, which greatly simplifies the process flow and saves equipment investment costs.
[0011] Preferably, the inner wall of the small molecule condenser is polished to be non-sticky, which can prevent the adhesion and accumulation of sticky materials on the surface of the component.
[0012] As a preferred embodiment, the inner diameter of the tube of the shell and tube heat exchanger is 1.0-5.0 cm. If the diameter of the heat exchange tube is too large, the heat exchange between the gas and the heat pipe will be insufficient, resulting in a decrease in the condensation effect and insufficient condensation; if the diameter of the heat exchange tube is too small, the equipment processing is difficult, and it is not conducive to the flushing of the adhesive, which increases the risk of blockage of the heat exchange tube.
[0013] Preferably, a small molecule condenser liquid phase outlet is provided at the bottom of the small molecule condenser, and the small molecule condenser liquid phase outlet is connected to the vacuum collection tank liquid phase inlet through a pipeline.
[0014] Preferably, two liquid phase inlets are provided at the top of the vacuum collecting tank, and a liquid phase outlet is provided at the bottom of the vacuum collecting tank.
[0015] As a preference, both the small molecule condenser and the vacuum collection tank are provided with a hot water jacket insulation layer to cool the high temperature mixed steam.
[0016] Preferably, the temperature of the heat medium jacket insulation layer is 0-90°C.
[0017] Preferably, the gas phase outlet of the condenser is connected to the vacuum buffer tank through a pipeline.
[0018] Preferably, a gas phase inlet is set at the top of the vacuum buffer tank, a gas phase outlet is set at the upper half of the side, and the gas phase inlet is connected to the gas phase outlet of the condenser through a pipeline. The pressure in the regulating device is balanced and stable.
[0019] Preferably, the gas phase outlet of the vacuum buffer tank is connected to a vacuum system.
[0020] Preferably, the vacuum system includes any one or more of a rotary vane vacuum pump, a roots vacuum pump, a screw vacuum pump, a water ring vacuum pump, a diffusion pump and a jet pump in series, and the outlet of the vacuum system is connected to the tail gas treatment system through a pipeline. The vacuum system evacuates the device, and the vacuum degree is determined by the vacuum system.
[0021] Preferably, the tail gas treatment system is provided with a water ring pump and a waste liquid tank connected by pipelines. The waste liquid tank can further absorb the water-soluble gas in the non-condensable gas after absorption and condensation, and prevent its toxic and harmful gas from being directly discharged into the atmosphere and polluting the environment.
[0022] The beneficial effects of the utility model are:
[0023] The utility model provides a small molecule collection device for devolatilization of nylon polymer, which removes small molecules of nylon 6 and various copolymers thereof, and adopts high boiling point substances to absorb high melting point oligomers. The condensed high boiling point substances can dissolve and absorb high melting point oligomers in high temperature mixed steam on the one hand, and on the other hand, downward air flow and liquid flow can also effectively wash away high melting point oligomers adhered to the inner wall surface, avoiding the blockage problem caused by large amount of accumulation thereof.
[0024] The utility model is cleverly designed. The baffle design on the upper end of the condenser divides the condenser into two parts, so that the mixed steam enters the condenser and forces a "U"-shaped gas path, thereby achieving a multi-stage condensation effect of a single device. All high-boiling point small molecules in the mixed steam can be separated and recovered to maximize economic benefits. On the one hand, since the utility model adopts an independent system, no new impurities are introduced during the entire collection process, so all the collected volatiles can be reused; on the other hand, the multi-stage condensation design of a single device greatly simplifies the recovery process and saves equipment investment costs.
[0025] In conventional hot water extraction processes, the main component of the system is desalted water, which still needs to be concentrated, cracked and purified after extraction to obtain small molecule raw materials with a high concentration, and some indestructible solid waste is also produced. Compared with conventional hot water extraction processes, the utility model does not require cracking, purification and other processes to obtain high-concentration small molecule volatiles. While ensuring the quality of the recovered liquid product, it greatly simplifies the process flow and reduces the production cost of nylon chips. At the same time, the equipment investment per unit production capacity is greatly reduced.
[0026] The utility model adds an exhaust gas treatment system to further absorb the water-soluble gas in the condensed non-condensable gas, thereby preventing the toxic and harmful gas from being directly discharged into the atmosphere to pollute the environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 , one Schematic diagram of the structure of a small molecule collection device for devolatilization of nylon polymer
[0028] In the figure, A01. Small molecule condenser, A02. Vacuum collecting tank, A03. Vacuum buffer tank, A04. Vacuum system, A05. Water ring pump, A06. Waste liquid tank, N01. Upper cover, N02. Shell and tube heat exchanger, N03. Lower cover, N04. Baffle, N05. Condenser gas phase inlet, N06. Condenser gas phase outlet, N07. Small molecule condenser liquid phase outlet, N08. Vacuum collecting tank liquid phase inlet, N09. Vacuum collecting tank liquid phase outlet, N10. Vacuum buffer tank gas phase inlet, N11. Vacuum buffer tank gas phase outlet. DETAILED DESCRIPTION
[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0030] like Figure 1A small molecule collection device for devolatilization of nylon polymer shown includes: a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04, and an exhaust gas treatment system. The small molecule condenser A01 is composed of an upper cover N01, a shell and tube heat exchanger N02 and a lower cover N03. A condenser gas phase inlet N05 and a condenser gas phase outlet N06 are provided on the top of the upper cover N01. The condenser gas phase inlet N05 and the condenser gas phase outlet N06 are set on opposite sides of the upper end of the small molecule condenser A01.
[0031] A small molecule condenser liquid phase outlet N07 is provided at the bottom of the lower cover N03, which is connected to the vacuum collection tank A02 below the small molecule condenser A01 through a pipeline.
[0032] The small molecule condenser A01 is provided with a heat medium jacket insulation layer. The water in the heat medium jacket protective layer is selected according to the material properties and has a temperature of 0-90°C. The water in the heat medium jacket insulation layer can exchange heat with the mixed steam entering from the gas phase inlet N05 of the condenser. The high melting point oligomers entrained in the mixed steam condense and adhere to the inner wall of the tube when contacting the heat exchange tubes. The low boiling point substances condense into liquid and flow down to the vacuum collection tank A02. The downward air and liquid flow will flush the bonded oligomers into the vacuum collection tank A02 to prevent the oligomers from bonding and aggregating to block the tubes.
[0033] A baffle N04 is provided inside the upper cover N01, and the baffle N04 evenly divides the upper cover N01 into two parts. The small molecule condenser A01 is divided by the baffle N04 to form a "U"-shaped loop. The mixed steam entering from the condenser gas phase inlet N05 is transported downward in the small molecule condenser A01 due to the blocking effect of the baffle N04, and exchanges heat with the water in the heat medium jacket protective layer set in the small molecule condenser A01, and performs a condensation. The mixed steam moves downward along the small molecule condenser A01 and then moves upward, and performs a secondary heat exchange with the water in the heat medium jacket protective layer set in the small molecule condenser A01, thereby realizing the multi-stage condensation effect of a single device, simplifying the process flow, saving equipment investment costs, further condensing the low-boiling point substances in the mixed steam, and realizing the full recovery of small molecules.
[0034] The inner diameter of the heat exchange pipe of the shell-and-tube heat exchanger N02 is 1.0cm-5.0cm. If the inner diameter of the heat exchange tube of the shell-and-tube heat exchanger N02 is too large, it will cause insufficient heat exchange between the gas and the heat pipe, resulting in a decrease in the condensation effect and insufficient condensation. If the inner diameter of the heat exchange tube of the shell-and-tube heat exchanger N02 is too small, the equipment processing is difficult, and it is not conducive to the flushing of the adhesive, which increases the risk of blockage of the heat exchange tube.
[0035] The inner wall of the small molecule condenser A01 is polished to be non-sticky. The inner wall of the small molecule condenser A01 after the non-stick treatment can prevent sticky materials from adhering and accumulating on the surface of the component.
[0036] A vacuum collecting tank liquid phase inlet N08 is provided at the center of the top of the vacuum collecting tank A02, which is connected to the liquid phase outlet N07 of the small molecule condenser through a pipeline to collect the bonded oligomers flushed from the small molecule condenser A01.
[0037] A vacuum collecting tank liquid phase outlet N09 is provided at the center of the bottom of the vacuum collecting tank A02 to discharge the recovered small molecules.
[0038] The condenser gas phase outlet N06 is connected to the vacuum buffer tank A03 through a pipeline.
[0039] The top of the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N10, and the upper part of the side is provided with a vacuum buffer tank gas phase outlet N11, and the vacuum buffer tank gas phase inlet N10 is connected to the condenser gas phase outlet N06 through a pipeline. The vacuum buffer tank A03 can adjust the gas pressure balance and stability in the device.
[0040] The gas phase outlet N11 of the vacuum buffer tank is connected to the vacuum system A04 through a pipeline. The vacuum system is a combination of any one or more of a rotary vane vacuum pump, a Roots vacuum pump, a screw vacuum pump, a water ring vacuum pump, a diffusion pump and a jet pump connected in series, and can be evacuated. The vacuum degree of the device is determined by the vacuum system A04.
[0041] The other end of the vacuum system A04 is connected to the tail gas treatment system through a pipeline.
[0042] The tail gas treatment system includes a water ring pump A05 and a waste liquid tank A06 connected by a pipeline.
[0043] The water ring pump A05 includes a liquid phase outlet and a gas phase outlet. The non-condensable gas passes through the vacuum buffer tank A03 and is cooled to room temperature, then passes through the vacuum system A04 and is sucked into the water ring pump A05. The water-soluble gas in the gas phase is absorbed by water, and the waste water flows into the waste liquid tank A06 through the liquid phase outlet to prevent its toxic and harmful gases from being directly discharged into the atmosphere and polluting the environment. The remaining gases are discharged into the atmosphere through the gas phase outlet.
[0044] Example 1
[0045] A small molecule collection device for nylon 6 devolatilization comprises a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04 and an exhaust gas treatment system which are connected in sequence.
[0046] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a Roots vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-stick treated.
[0047] 90℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 280℃ high-temperature mixed steam (including monomer caprolactam and small molecular oligomers) obtained after the polymerization and devolatilization of nylon 6 enters the small molecular condensing tank A01 from the condenser gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 1.0 cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange tubes. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0048] Example 2
[0049] A small molecule collection device for nylon 6 devolatilization comprises a small molecule condenser, a vacuum buffer tank, a vacuum collection tank, a vacuum system and an exhaust gas treatment system which are connected in sequence.
[0050] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a rotary vane vacuum pump, a screw vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-sticky.
[0051] 80℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 280℃ high-temperature mixed steam (including monomer caprolactam and small molecular oligomers) obtained by devolatilization of nylon 6 / 66 copolymerization enters the small molecular condensing tank A01 from the gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 2.0 cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange shell and tube. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0052] Example 3
[0053] A small molecule collection device for devolatilization of nylon 6 and nylon 56 copolymerization comprises a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04 and an exhaust gas treatment system which are connected in sequence.
[0054] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a rotary vane vacuum pump, a Roots vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-sticky.
[0055] 60℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 260℃ high-temperature mixed steam (including monomer caprolactam and small molecular oligomers) obtained by devolatilization of nylon 6 / 66 copolymerization enters the small molecular condensing tank A01 from the gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 2.5cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange shell and tube. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0056] Example 4
[0057] A small molecule collection device for devolatilization of nylon 6 and nylon 56 copolymerization comprises a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04 and an exhaust gas treatment system which are connected in sequence.
[0058] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a rotary vane vacuum pump, a Roots vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-sticky.
[0059] 40℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 260℃ high-temperature mixed steam obtained by devolatilization of nylon 6 / 66 copolymerization enters the small molecule condensing tank A01 from the gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 3.0 cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange tubes. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0060] Example 5
[0061] A small molecule collection device for devolatilization of nylon 6 and nylon 66 copolymerization comprises a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04 and an exhaust gas treatment system which are connected in sequence.
[0062] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a rotary vane vacuum pump, a Roots vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-sticky.
[0063] 20℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 250℃ high-temperature mixed steam (including monomer caprolactam and small molecular oligomers) obtained by devolatilization of nylon 6 / 66 copolymerization enters the small molecular condensing tank A01 from the gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 4.0 cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange shell and tube. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0064] Example 6
[0065] A small molecule collection device for devolatilization of nylon 6 and nylon 66 copolymerization comprises a small molecule condenser A01, a vacuum collection tank A02, a vacuum buffer tank A03, a vacuum system A04 and an exhaust gas treatment system which are connected in sequence.
[0066] The small molecule condenser A01 is provided with a condenser gas phase inlet N01, a condenser gas phase outlet N02, and a small molecule condenser liquid phase outlet N03; the vacuum collecting tank A02 is provided with a liquid phase inlet N04 and a liquid phase outlet N05; the vacuum buffer tank A03 is provided with a vacuum buffer tank gas phase inlet N06 and a vacuum buffer tank gas phase outlet N07; the small molecule condenser A01 and the vacuum collecting tank A03 are both provided with a heat medium insulation jacket; the vacuum system A04 adopts a rotary vane vacuum pump, a Roots vacuum pump and a screw vacuum system combined pump group; the inner wall of the small molecule condenser A01 is polished and non-sticky.
[0067] 0℃ water is passed through the jacket insulation layer of the vacuum condensing tank A01 and the vacuum collecting tank A03 for insulation. The 250℃ high-temperature mixed steam (including monomer caprolactam and small molecular oligomers) obtained by devolatilization of nylon 6 / 66 copolymerization enters the small molecular condensing tank A01 from the gas phase inlet N01 through the conveying pipeline. The high-temperature mixed steam enters the shell-and-tube heat exchanger N02 with an inner diameter of 5.0 cm to exchange heat and condense with water. Caprolactam is condensed from gas to liquid, and high-melting-point oligomers adhere to the inner wall of the heat exchange shell and tube. Under the flushing and absorption of the condensed liquid caprolactam and the high-temperature mixed steam, it flows into the vacuum collecting tank A02. The remaining uncondensed gas comes into contact with the heat exchange tubes again through the "U"-shaped gas path and is completely condensed in the tubes. The remaining non-condensable gas is cooled to room temperature through the vacuum buffer tank and then enters the exhaust gas treatment system through the vacuum system A04. The exhaust gas treatment system includes a water ring pump A05 and a waste liquid tank A06. The non-condensable gas is sucked into the water ring pump A05, and the water-soluble gas in the gas phase is absorbed by water and flows into the waste liquid tank A06. The remaining gas is discharged into the atmosphere.
[0068] The utility model has low processing cost, simple process flow, environmental friendliness and good condensation effect.
[0069] The above description is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent transformation made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.
Claims
1. A small molecule collection device for nylon polymer devolatilization, characterized in that: It comprises a small molecule condenser (A01) and a vacuum collecting tank (A02) connected to the bottom of the small molecule condenser (A01) through a pipeline, a baffle (N04) is provided inside the small molecule condenser (A01), and the small molecule condenser (A01) is connected to a non-condensable gas treatment system through a pipeline, and the non-condensable gas treatment system comprises a vacuum buffer tank (A03), a vacuum system (A04) and an exhaust gas treatment system connected in sequence.
2. A small molecule collection device for nylon polymer devolatilization according to claim 1, characterized in that: The upper cover (N01) of the small molecule condenser (A01) is provided with a condenser gas phase inlet (N05) and a condenser gas phase outlet (N06); the baffle plate (N04) is arranged inside the upper cover (N01); the condenser gas phase inlet (N05) and the condenser gas phase outlet (N06) are located on both sides of the baffle plate (N04); and the condenser gas phase outlet (N06) is connected to a non-condensable gas treatment system through a pipeline.
3. A small molecule collection device for nylon polymer devolatilization according to claim 1, characterized in that: The vacuum collecting tank (A02) is provided with a vacuum collecting tank liquid phase inlet (N08) at the top and a vacuum collecting tank liquid phase outlet (N09) at the bottom.
4. A small molecule collection device for nylon polymer devolatilization according to claim 1, characterized in that: A vacuum buffer tank gas phase inlet (N10) is provided on the top of the vacuum buffer tank (A03), and the vacuum buffer tank gas phase inlet (N10) is connected to the small molecule condenser gas phase outlet (N06) through a pipeline. A vacuum buffer tank gas phase outlet (N11) is provided on the side of the vacuum buffer tank (A03), and the vacuum buffer tank gas phase outlet (N11) is connected to the vacuum system (A04) through a pipeline.
5. The small molecule collection device for nylon polymer devolatilization according to claim 1, characterized in that: The outlet of the vacuum system (A04) is connected to the tail gas treatment system through a pipeline.
6. A small molecule collection device for nylon polymer devolatilization according to claim 1 or 5, characterized in that: The tail gas treatment system comprises a water ring pump (A05) and a waste liquid tank (A06); the water ring pump (A05) is provided with a gas phase outlet and a liquid phase outlet; the gas phase outlet is communicated with the outside, and the liquid phase outlet is connected to the waste liquid tank (A06).
7. A small molecule collection device for nylon polymer devolatilization according to claim 1 or 2, characterized in that: The small molecule condenser (A01) is provided with a heat medium jacket insulation layer, and the inner wall of the small molecule condenser (A01) is polished and non-sticky.
8. A small molecule collection device for nylon polymer devolatilization according to claim 1 or 3, characterized in that: The vacuum collecting tank (A02) is provided with a heat medium jacket insulation layer.
9. A small molecule collection device for nylon polymer devolatilization according to claim 1 or 2, characterized in that: The baffle plate (N04) is vertically placed in the upper cover (N01), dividing the upper cover (N01) into two parts.
10. A small molecule collection device for nylon polymer devolatilization according to claim 2, characterized in that: The inner diameter of the tube of the shell and tube heat exchanger (N02) is 1.0-5.0cm.