System and method for treating N-methylpyrrolidone dirty solvent of natural gas acetylene device

Abstract

The invention discloses a natural gas acetylene device N-methyl pyrrolidone dirty solvent treatment system and method, and belongs to the technical field of chemical engineering. The treatment system comprises a film evaporator connected out of a natural gas-to-acetylene solvent concentration system and a condenser connected out of the film evaporator, the film evaporator comprises a jacketed heating main body, a heat exchange material distribution section and a blanking cone section; a heat exchange mechanism and a material distribution mechanism are arranged in the heat exchange material distribution section; a film scraping plate and a spiral material pushing disc are arranged in the jacket type heating main body; a spiral feeder is arranged in the blanking cone section; the discharging cone section is connected with a polymer conveying pipe; and a regenerated solvent conveying pipe is connected between the condenser and the natural gas-to-acetylene solvent concentration system. The invention discloses a method for treating the N-methyl pyrrolidone dirty solvent of the natural gas acetylene device by adopting the system. The method disclosed by the invention is high in solvent yield, strong in operation continuity, high in automation degree, safe, low in environmental protection risk, low in labor intensity of workers, and small in equipment investment and occupied area.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a system and method for treating N-methylpyrrolidone contaminated solvent of a natural gas acetylene device. Background Art

[0002] As an important chemical raw material, acetylene is usually produced by the calcium carbide process and the natural gas partial oxidation process. Compared with the calcium carbide process, the natural gas process has the advantages of low energy consumption, full utilization of by-products, and low environmental pollution. It has been widely used at home and abroad. In the natural gas process, natural gas is cracked, compressed, and concentrated to produce acetylene products.

[0003] In the concentration process of natural gas acetylene plant, polymers generated by some higher hydrocarbons are formed into colloidal substances in N-methylpyrrolidone solvent, which seriously affects the selective absorption effect of the solvent on the process gas and causes system blockage. In order to limit the content of polymers in the concentration circulating solvent within a certain range, a certain amount of solvent needs to be continuously extracted at the outlet of the solvent circulation pump for regeneration. The solvent treatment process of the existing acetylene plant usually adopts a process combining distillation and dry distillation to separate polymers and recover solvents. The dry distillation adopts an intermittent operation process in which the dry distillation tank evaporates the solvent until polymer residue appears under vacuum. The process includes a series of complex operation procedures such as vacuum establishment of the dry distillation tank, steam heating, natural cooling after the dry distillation is qualified, nitrogen injection to break the vacuum, manual opening of the discharge port on the dry distillation tank for manual slag removal, and cleaning of the dry distillation tank. The dry distillation tank adopts multiple openings and one standby, and each dry distillation tank is equipped with an independent vacuum establishment & solvent vapor condensation collection system, with a large number of equipment and a large footprint. Each dry distillation tank must repeat the dry distillation operation many times a day, the process is cumbersome, and the operator's work intensity is high. Polymer residues are carcinogenic and extremely flammable. Polymers in a dry state are prone to spontaneous combustion. The safety and occupational health risks of manual deslagging in the retort are very high.

[0004] Therefore, providing a method for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, which has high solvent yield, strong operation continuity, high degree of automation, low safety and environmental risks, low labor intensity for workers, and small equipment investment and land occupation, has become a problem to be urgently solved by technical personnel in this field. Summary of the invention

[0005] One of the purposes of the present invention is to provide a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene plant to at least solve some of the above problems.

[0006] The second object of the present invention is to provide a method for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, which is carried out using the above-mentioned system.

[0007] The third object of the present invention is to provide a new type of thin film evaporator. The characteristic of this thin film evaporator is that it recovers the heat of the gas phase outlet of the ordinary thin film evaporator, is suitable for the uniform distribution and transportation of high-viscosity materials, is suitable for preventing heat-sensitive materials from deteriorating, integrates the functions of three devices: a polymer collection tank and a polymer delivery pump, saves equipment investment, and simplifies operation and maintenance procedures.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] The present invention discloses a N-methylpyrrolidone contaminated solvent treatment system for a natural gas acetylene device, comprising a thin film evaporator connected to a natural gas acetylene solvent concentration system, and a condenser connected to the thin film evaporator;

[0010] The thin film evaporator comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body;

[0011] The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas acetylene solvent concentration system, and a distribution mechanism connected to the heat exchange mechanism;

[0012] The jacketed heating body is provided with a scraping plate and a spiral pusher plate arranged below the scraping plate;

[0013] The upper part of the jacket of the jacket-type heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet;

[0014] A spiral feeder connected to a spiral push plate is provided in the unloading cone section;

[0015] A polymer external transmission pipe is connected to the discharge cone section, and a regeneration solvent transmission pipe is connected between the condenser and the natural gas acetylene solvent concentration system.

[0016] In the present invention, the outer jacket of the jacketed heating body adopts a variable temperature setting, the upper jacket is provided with a superheated steam inlet, and high-temperature superheated steam is used to achieve a good evaporation and separation effect on the solvent. The heating medium in the lower jacket is a saturated steam condensate with a lower temperature after condensation, which plays an anti-polymerization role while continuing to heat and evaporate the solvent, thereby avoiding long-term high-temperature heating causing the material to generate large molecular tar and block the equipment.

[0017] In some embodiments of the present invention, the heat exchange material distribution section is provided with a contaminated solvent inlet and a solvent vapor outlet; the natural gas to acetylene solvent concentration system is connected to the contaminated solvent inlet; and the condenser is connected to the solvent vapor outlet.

[0018] In some embodiments of the present invention, the heat exchange mechanism includes a heat exchange coil disposed in the heat exchange material distribution section and located below the solvent vapor outlet, and the inlet end of the heat exchange coil is connected to the dirty solvent inlet;

[0019] The distribution mechanism comprises a centrifugal liquid collecting distributor connected with the heat exchange mechanism and used for evenly distributing the polluted solvent to the heating surface of the inner wall of the jacketed heating body.

[0020] In some embodiments of the present invention, a variable frequency motor for driving a material distribution mechanism, a scraper plate, a spiral pusher plate and a spiral feeder is provided on the top of the heat exchange material distribution section.

[0021] In some embodiments of the present invention, the variable frequency motor drive shaft is connected to a rotating shaft, and the rotating shaft is respectively connected to the centrifugal liquid collector distributor, the scraper plate, the spiral pusher plate and the spiral feeder.

[0022] In some embodiments of the present invention, the polymer external delivery pipe is connected to an external incineration device;

[0023] The regeneration solvent delivery pipe is provided with a regeneration solvent pump and a liquid level regulating valve.

[0024] In some embodiments of the present invention, the condenser is connected to a non-condensable gas external transmission pipe connected to an external incineration device, and a vacuum pump is provided on the non-condensable gas external transmission pipe.

[0025] In some embodiments of the present invention, the superheated steam inlet of the jacketed heating body is connected to a heating steam delivery pipe, the saturated steam condensate outlet is connected to a steam condensate delivery pipe, and the heating steam delivery pipe is provided with a pressure regulating valve, a pressure controller and a flow controller in sequence according to the steam flow direction;

[0026] A temperature controller is arranged in the middle and lower part of the jacketed heating body, and the temperature controller over-controls the pressure / flow selection controller, and the pressure / flow selection controller signal is connected to the pressure regulating valve;

[0027] A first liquid level controller is arranged on the unloading cone section and is connected with the frequency conversion motor signal.

[0028] The present invention discloses a method for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, which is carried out by using the above-mentioned system.

[0029] In some embodiments of the present invention, the method comprises the following steps: the contaminated solvent from the natural gas to acetylene solvent concentration system is fed into the heat exchange distribution section of the thin film evaporator, and heat is exchanged with the superheated solvent vapor from the jacketed heating body in the heat exchange coil; and then enters the centrifugal liquid collecting distributor, and is evenly distributed to the heating wall surface of the jacketed heating body under the action of the centrifugal liquid collecting distributor;

[0030] The scraper plate continuously and evenly scrapes the material on the heated wall surface into a liquid film of uniform thickness; after the scraper evaporation, the light components in the dirty solvent are heated and evaporated;

[0031] As the light components with lower boiling points in the polluted solvent continue to evaporate, a viscous colloid polymer is formed in the lower area of ​​the jacketed heating body. The colloid polymer is pushed to the discharge cone section by the action of the spiral pusher, and then pushed out of the thin film evaporator by the action of the spiral feeder, and then sent to the external incineration equipment for treatment;

[0032] The light components in the contaminated solvent are heated and evaporated, forming a superheated steam stream that rises. After recovering part of the heat in the heat exchange material section at the top of the thin film evaporator, it is discharged from the top of the thin film evaporator and enters the condenser for condensation and liquefaction. The liquefied regenerated solvent is sent back to the concentration process for recycling, and the light component non-condensable gas is sent to the incineration device for treatment.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention is scientifically designed and ingeniously conceived. The treatment system for N-methylpyrrolidone contaminated solvent of the natural gas to acetylene device of the present invention creatively adopts a thin film evaporator suitable for the treatment of acetylene contaminated solvent. The contaminated solvent is directly sent into the thin film evaporator without heating, and heat recovery and efficient separation of solvent and polymer are realized in the thin film evaporator. The built-in spiral push plate and spiral feeder of the thin film evaporator are used to send out high-viscosity colloid polymers after solvent recovery, without the need for an external polymer delivery pump. Thermosensitive substances will not generate larger molecular tars and clog equipment under long-term high-temperature heating. The solvent content in the polymer at the bottom outlet of the thin film evaporator of the present invention is extremely low, and it can be directly sent to the incineration device for treatment without further solvent recovery treatment.

[0035] The method of the present invention can replace the solvent treatment process combining continuous distillation and intermittent distillation used in existing natural gas acetylene devices. The method of the present invention has many advantages such as high solvent yield, strong operation continuity, high degree of automation, low safety and environmental protection risks, low labor intensity for workers, small equipment investment and land occupation, etc. It can be used as a technical upgrade plan for the backward process of existing natural gas acetylene devices and be fully promoted in the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Attached Figure 1 It is a system structure diagram of the present invention.

[0037] Attached Figure 2 It is a structural diagram of the thin film evaporator of the present invention.

[0038] The names corresponding to the reference numerals are:

[0039] 1-thin film evaporator, 2-condenser, 3-natural gas to acetylene solvent concentration system, 4-external incineration equipment, 5-regeneration solvent pump, 6-liquid level regulating valve, 7-vacuum pump, 8-pressure / flow selection controller;

[0040] 11- frequency conversion motor, 12- rotating shaft, 13- dirty solvent inlet, 14- solvent vapor outlet, 15- heat exchange coil, 16- centrifugal liquid collector, 17- scraper plate, 18- spiral push plate, 19- spiral feeder;

[0041] 101- polymer external delivery pipe, 102- regeneration solvent delivery pipe, 103- non-condensable gas external delivery pipe, 104- heating steam delivery pipe, 105- steam condensate external delivery pipe;

[0042] PV-pressure regulating valve, FC-flow controller, PC-pressure controller, TC-temperature controller, LC1-first liquid level controller, LC2-second liquid level controller. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] As attached Figure 1 and attached Figure 2 As shown, the present invention discloses a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, comprising a thin film evaporator 1 connected to a natural gas acetylene solvent concentration system 3, and a condenser 2 connected to the thin film evaporator 1;

[0046] The thin film evaporator 1 comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body; the heat exchange material distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system 3, and a material distribution mechanism connected to the heat exchange mechanism;

[0047] The jacketed heating body is provided with a scraping plate 17 and a spiral pusher plate 18 provided below the scraping plate 17;

[0048] The upper part of the jacket of the jacketed heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet;

[0049] A spiral feeder 19 connected to a spiral push plate 18 is provided in the unloading cone section;

[0050] A polymer delivery pipe 101 is connected to the discharge cone section, and a regeneration solvent delivery pipe 102 is connected between the condenser 2 and the natural gas to acetylene solvent concentration system 3 .

[0051] The outer jacket of the jacketed heating body described in this embodiment adopts a variable temperature setting. The upper jacket is provided with a superheated steam inlet, and high-temperature superheated steam is used to achieve a good evaporation and separation effect on the solvent. The heating medium in the lower jacket is a saturated steam condensate with a lower temperature after condensation. While continuing to heat and evaporate the solvent, it plays an anti-polymerization role to avoid long-term high-temperature heating causing the material to generate large molecular tar and block the equipment.

[0052] Example 2

[0053] As attached Figure 1 and attached Figure 2 As shown, the present invention discloses a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, comprising a thin film evaporator 1 connected to a natural gas acetylene solvent concentration system 3, and a condenser 2 connected to the thin film evaporator 1;

[0054] The thin film evaporator 1 comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body;

[0055] The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system 3, and a distribution mechanism connected to the heat exchange mechanism;

[0056] The jacketed heating body is provided with a scraping plate 17 and a spiral pusher plate 18 provided below the scraping plate 17;

[0057] The upper part of the jacket of the jacketed heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet;

[0058] A spiral feeder 19 connected to a spiral push plate 18 is provided in the unloading cone section;

[0059] A polymer delivery pipe 101 is connected to the discharge cone section, and a regeneration solvent delivery pipe 102 is connected between the condenser 2 and the natural gas to acetylene solvent concentration system 3 .

[0060] The heat exchange material distribution section is provided with a dirty solvent inlet 13 and a solvent vapor outlet 14 ; the natural gas to acetylene solvent concentration system 3 is connected to the dirty solvent inlet 13 ; and the condenser 2 is connected to the solvent vapor outlet 14 .

[0061] The heat exchange mechanism includes a heat exchange coil 15 disposed in the heat exchange material distribution section and located below the solvent vapor output port 14, and the inlet end of the heat exchange coil 15 is connected to the dirty solvent inlet 13;

[0062] The distribution mechanism includes a centrifugal liquid collecting distributor 16 connected to the heat exchange mechanism for evenly distributing the contaminated solvent to the heating surface of the inner wall of the jacketed heating body.

[0063] This embodiment 2 provides a more preferred technical solution for the distribution mechanism and the heat exchange mechanism on the basis of embodiment 1. Specifically, the heat exchange mechanism includes a heat exchange coil 15 arranged in the heat exchange distribution section and located below the solvent vapor outlet 14, and the inlet end of the heat exchange coil 15 is connected to the dirty solvent inlet 13; the distribution mechanism includes a centrifugal liquid collection distributor 16 connected to the heat exchange mechanism for evenly distributing the dirty solvent to the heating surface of the inner wall of the jacketed heating body.

[0064] Example 3

[0065] As attached Figure 1 and attached Figure 2 As shown, the present invention discloses a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, comprising a thin film evaporator 1 connected to a natural gas acetylene solvent concentration system 3, and a condenser 2 connected to the thin film evaporator 1;

[0066] The thin film evaporator 1 comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body;

[0067] The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system 3, and a distribution mechanism connected to the heat exchange mechanism;

[0068] The jacketed heating body is provided with a scraping plate 17 and a spiral material pushing plate 18 provided below the scraping plate 17;

[0069] The upper part of the jacket in the jacket-type heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet;

[0070] A spiral feeder 19 connected to a spiral push plate 18 is provided in the unloading cone section;

[0071] A polymer delivery pipe 101 is connected to the discharge cone section, and a regeneration solvent delivery pipe 102 is connected between the condenser 2 and the natural gas to acetylene solvent concentration system 3 .

[0072] The heat exchange material distribution section is provided with a dirty solvent inlet 13 and a solvent vapor outlet 14 ; the natural gas to acetylene solvent concentration system 3 is connected to the dirty solvent inlet 13 ; and the condenser 2 is connected to the solvent vapor outlet 14 .

[0073] The heat exchange mechanism includes a heat exchange coil 15 disposed in the heat exchange material distribution section and located below the solvent vapor output port 14, and the inlet end of the heat exchange coil 15 is connected to the dirty solvent inlet 13;

[0074] The distribution mechanism includes a centrifugal liquid collecting distributor 16 connected to the heat exchange mechanism for evenly distributing the contaminated solvent to the heating surface of the inner wall of the jacketed heating body.

[0075] The top of the heat exchange distribution section is provided with a frequency conversion motor 11 for driving a centrifugal liquid collecting distributor 16, a scraping plate 17, a spiral pusher plate 18, and a spiral feeder 19. The drive shaft of the frequency conversion motor 11 is connected with a rotating shaft 12, and the rotating shaft 12 is respectively connected with the centrifugal liquid collecting distributor 16, the scraping plate 17, the spiral pusher plate 18, and the spiral feeder 19.

[0076] This embodiment 3 provides a more preferred technical solution based on embodiment 2. Specifically, a variable frequency motor 11 is provided at the top of the heat exchange distribution section to drive a centrifugal liquid collecting distributor 16, a scraper plate 17, a spiral pusher plate 18, and a spiral feeder 19. The drive shaft of the variable frequency motor 11 is connected to a rotating shaft 12, and the rotating shaft 12 is respectively connected to the centrifugal liquid collecting distributor 16, the scraper plate 17, the spiral pusher plate 18, and the spiral feeder 19.

[0077] Example 4

[0078] As attached Figure 1 and attached Figure 2 As shown, the present invention discloses a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, comprising a thin film evaporator 1 connected to a natural gas acetylene solvent concentration system 3, and a condenser 2 connected to the thin film evaporator 1;

[0079] The thin film evaporator 1 comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body;

[0080] The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system 3, and a distribution mechanism connected to the heat exchange mechanism;

[0081] The jacketed heating body is provided with a scraping plate 17 and a spiral material pushing plate 18 provided below the scraping plate 17;

[0082] The upper part of the jacket of the jacketed heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet; a spiral feeder 19 connected to a spiral pusher plate 18 is provided in the discharge cone section;

[0083] A polymer delivery pipe 101 is connected to the discharge cone section, and a regeneration solvent delivery pipe 102 is connected between the condenser 2 and the natural gas to acetylene solvent concentration system 3 .

[0084] The heat exchange material distribution section is provided with a dirty solvent inlet 13 and a solvent vapor outlet 14 ; the natural gas to acetylene solvent concentration system 3 is connected to the dirty solvent inlet 13 ; and the condenser 2 is connected to the solvent vapor outlet 14 .

[0085] The heat exchange mechanism includes a heat exchange coil 15 disposed in the heat exchange material distribution section and located below the solvent vapor output port 14, and the inlet end of the heat exchange coil 15 is connected to the dirty solvent inlet 13;

[0086] The distribution mechanism includes a centrifugal liquid collecting distributor 16 connected to the heat exchange mechanism for evenly distributing the contaminated solvent to the heating surface of the inner wall of the jacketed heating body.

[0087] The top of the heat exchange distribution section is provided with a frequency conversion motor 11 for driving a centrifugal liquid collecting distributor 16, a scraping plate 17, a spiral pusher plate 18, and a spiral feeder 19. The drive shaft of the frequency conversion motor 11 is connected with a rotating shaft 12, and the rotating shaft 12 is respectively connected with the centrifugal liquid collecting distributor 16, the scraping plate 17, the spiral pusher plate 18, and the spiral feeder 19.

[0088] The polymer external delivery pipe 101 is connected to the external incineration equipment 4 .

[0089] The regeneration solvent delivery pipe 102 is provided with a regeneration solvent pump 5 and a liquid level regulating valve 6 .

[0090] The condenser 2 is connected to a non-condensable gas transmission pipe 103 connected to an external incineration device 4 , and a vacuum pump 7 is provided on the non-condensable gas transmission pipe 103 .

[0091] This embodiment 4 provides a more preferred technical solution based on embodiment 3. Specifically, the polymer delivery pipe 101 is directly connected to the external incineration equipment 4, without the need for an external polymer delivery pump. The regeneration solvent delivery pipe 102 is provided with a regeneration solvent pump 5 and a liquid level regulating valve 6. The condenser 2 is connected to a non-condensable gas delivery pipe 103 connected to the external incineration equipment 4, and a vacuum pump 7 is provided on the non-condensable gas delivery pipe 103.

[0092] Example 5

[0093] As attached Figure 1 and attached Figure 2 As shown, the present invention discloses a system for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, comprising a thin film evaporator 1 connected to a natural gas acetylene solvent concentration system 3, and a condenser 2 connected to the thin film evaporator 1;

[0094] The thin film evaporator 1 comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body;

[0095] The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system 3, and a distribution mechanism connected to the heat exchange mechanism;

[0096] The jacketed heating body is provided with a scraping plate 17 and a spiral pusher plate 18 provided below the scraping plate 17;

[0097] The upper part of the jacket of the jacketed heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet; a spiral feeder 19 connected to a spiral pusher plate 18 is provided in the discharge cone section;

[0098] A polymer delivery pipe 101 is connected to the discharge cone section, and a regeneration solvent delivery pipe 102 is connected between the condenser 2 and the natural gas to acetylene solvent concentration system 3 .

[0099] The heat exchange material distribution section is provided with a dirty solvent inlet 13 and a solvent vapor outlet 14 ; the natural gas to acetylene solvent concentration system 3 is connected to the dirty solvent inlet 13 ; and the condenser 2 is connected to the solvent vapor outlet 14 .

[0100] The heat exchange mechanism includes a heat exchange coil 15 disposed in the heat exchange material distribution section and located below the solvent vapor output port 14, and the inlet end of the heat exchange coil 15 is connected to the dirty solvent inlet 13;

[0101] The distribution mechanism includes a centrifugal liquid collecting distributor 16 connected to the heat exchange mechanism for evenly distributing the contaminated solvent to the heating surface of the inner wall of the jacketed heating body.

[0102] The top of the heat exchange distribution section is provided with a frequency conversion motor 11 for driving a centrifugal liquid collecting distributor 16, a scraping plate 17, a spiral pusher plate 18, and a spiral feeder 19. The drive shaft of the frequency conversion motor 11 is connected with a rotating shaft 12, and the rotating shaft 12 is respectively connected with the centrifugal liquid collecting distributor 16, the scraping plate 17, the spiral pusher plate 18, and the spiral feeder 19.

[0103] The polymer external delivery pipe 101 is connected to the external incineration equipment 4, and no external polymer delivery pump is required.

[0104] The regeneration solvent delivery pipe 102 is provided with a regeneration solvent pump 5 and a liquid level regulating valve 6 .

[0105] The condenser 2 is connected to a non-condensable gas transmission pipe 103 connected to an external incineration device 4 , and a vacuum pump 7 is provided on the non-condensable gas transmission pipe 103 .

[0106] The superheated steam inlet of the jacketed heating body is connected to a heating steam delivery pipe 104, and the saturated steam condensate outlet is connected to a steam condensate delivery pipe 105. The heating steam delivery pipe 104 is provided with a pressure regulating valve PV, a pressure controller PC and a flow controller FC in sequence according to the steam flow direction;

[0107] A temperature controller TC is provided in the lower middle part of the jacketed heating body.

[0108] The temperature controller TC signal over-controls the pressure / flow selection controller 8, and the pressure / flow selection flow controller 8 signal is connected to the pressure regulating valve PV; the pressure / flow selection controller 8 over-controls the flow and pressure of the heating steam according to the signal transmitted by the temperature controller TC.

[0109] A first liquid level controller LC1 is provided on the unloading cone section and is connected to the variable frequency motor 11 by signal.

[0110] The condenser 2 is provided with a second liquid level controller LC2 , which is signal-connected to the liquid level regulating valve 6 and is used to control the opening of the liquid level regulating valve 6 .

[0111] This embodiment 5 provides a more preferred technical solution based on embodiment 4. Specifically, the superheated steam inlet of the jacketed heating body is connected to a heating steam delivery pipe 104, and the saturated steam condensate outlet is connected to a steam condensate delivery pipe 105. The heating steam delivery pipe 104 is provided with a pressure regulating valve PV, a pressure controller PC and a flow controller FC in sequence according to the steam flow direction; a temperature controller TC is provided in the middle and lower part of the jacketed heating body, and the temperature controller TC signal over-controls the pressure / flow selection controller 8, and the pressure / flow selection controller 8 signal is connected to the pressure regulating valve PV; the pressure / flow selection controller 8 over-controls the flow and pressure of the heating steam according to the signal transmitted by the temperature controller TC. A first liquid level controller LC1 is provided on the unloading cone section, which is connected to the frequency conversion motor 11 by signal. The condenser 2 is provided with a second liquid level controller LC2, which is connected to the liquid level regulating valve 6 by signal, and is used to control the opening of the liquid level regulating valve 6.

[0112] Example 6

[0113] This embodiment discloses a method for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, which is carried out using the system of embodiment 5; specifically, the following steps are included:

[0114] The contaminated solvent from the acetylene solvent concentration system of natural gas is sent to the heat exchange distribution section of the thin film evaporator under vacuum state, and heat is exchanged with the superheated solvent steam from the jacketed heating body in the heat exchange coil; then it enters the centrifugal liquid collector distributor, and is evenly distributed to the heating wall surface of the jacketed heating body under the action of the centrifugal liquid collector distributor;

[0115] The scraper plate continuously and evenly scrapes the material on the heated wall surface into a liquid film of uniform thickness; after scraping evaporation, the light components in the dirty solvent (N-methylpyrrolidone and a small amount of non-condensable gas) are heated and evaporated.

[0116] As the light components with lower boiling points in the polluted solvent continue to evaporate, a viscous colloidal polymer is formed in the lower area of ​​the jacketed heating body. The colloidal polymer is pushed to the discharge cone section by the action of the spiral pushing plate, and then pushed out of the thin film evaporator by the action of the spiral feeder, and then sent to the external incineration equipment for treatment.

[0117] The light components in the dirty solvent are heated and evaporated, forming a superheated steam stream that rises, exchanges heat with the dirty solvent in the heat exchange coil to recover heat, and then is discharged from the top of the thin film evaporator and enters the condenser for condensation and liquefaction;

[0118] The liquefied N-methylpyrrolidone is sent back to the concentration process for recycling, and the light component non-condensable gas is sent to external incineration equipment for treatment.

[0119] The centrifugal liquid collecting distributor of the present invention adopts a conical trough structure, and the conical surface has non-uniformly distributed openings. The distributor is driven to rotate by a rotating shaft driven by a motor. The dirty solvent collected in the trough is tangentially thrown through the holes on the conical surface under the action of centrifugal force, and then the dirty solvent is evenly distributed to the heating wall surface of the evaporator.

[0120] The invention ensures that a continuous and uniform liquid film generates high-speed turbulence through a rotating scraper, and prevents the liquid film from coking and polymerizing on the heating surface, thereby improving the heat transfer coefficient and ensuring the vaporization rate of the N-methylpyrrolidone solvent with a lower boiling point in the dirty solvent.

[0121] As the N-methylpyrrolidone solvent in the dirty solvent continues to evaporate, the polymer concentration in the liquid film in the lower area of ​​the heated wall of the thin film evaporator continues to increase, and forms a viscous colloidal polymer under high temperature, which adheres to the heated inner wall, affecting the flow of the medium and the heat exchange effect. The present invention creatively uses a spiral pusher at the bottom of the scraper plate, which spirally pushes the high-viscosity polymer attached to the inner wall into the discharge cone section while scraping the film. The spiral pusher of the present invention has a pusher-type thread on the outside, and the inner cylinder is driven to rotate by a shaft driven by a motor. The thread generates a downward driving force during rotation, and the high-viscosity polymer attached to the inner wall is spirally pushed into the discharge cone section.

[0122] A screw feeder is provided in the unloading cone section of the present invention. The screw feeder is preferably designed as a single screw pump. The screw is driven by a motor-driven rotating shaft to rotate, and the organic polymer collected in the cone section is squeezed and sent to an external incineration device for combustion treatment and heat recovery.

[0123] The centrifugal distributor, film scraper, spiral pusher and spiral feeder in the thin film evaporator of the present invention are all driven to rotate by a variable frequency motor. The liquid level of the polymer in the unloading cone section is maintained by controlling the speed of the variable frequency motor.

[0124] The thin film evaporator of the present invention is specially designed for high-grade acetylene polymers in acetylene contaminated solvents (upper finned heat exchange coils to recover heat + centrifugal liquid collectors to ensure recovery effect + spiral scraper plates to improve heat transfer efficiency and solvent recovery rate + lower polymer conveyors to reduce equipment investment), and the use effect is significantly better than the combination of traditional scraper-type or one-way thin film evaporators + contaminated solvent preheaters + polymer collection tanks and conveying pumps. The present invention has the advantages of low investment, simple operation, and full energy utilization. With the system of the present invention, the contaminated solvent is directly fed into the thin film evaporator without heating, and efficient separation of the solvent and the polymer is achieved in the thin film evaporator. The polymer at the bottom outlet of the thin film evaporator has an extremely low solvent content and can be directly sent to an incineration device for treatment without further solvent recovery treatment.

[0125] According to the temperature characteristics of the polymer in the contaminated solvent, the present invention arranges thermometers at the upper and lower parts of the jacketed heating body of the thin film evaporator, adopts an advanced control method of temperature cascade and over-control of the amount of heating steam of the thin film evaporator, accurately controls the evaporation temperature of the thin film evaporator, improves the solvent yield, and prevents the polymer from coking and sticking into blocks.

[0126] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solution of the present invention, but not to limit it, and certainly not to limit the patent scope of the present invention. Any changes or modifications that are made to the main design concept and spirit of the present invention without any substantial meaning, and the technical problems they solve are still consistent with the present invention, should be included in the protection scope of the present invention.

Claims

1. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system, characterized in that: It comprises a thin film evaporator (1) connected to a natural gas acetylene solvent concentration system (3), and a condenser (2) connected to the thin film evaporator (1); The thin film evaporator (1) comprises a jacketed heating body, a heat exchange material distribution section connected to the top of the jacketed heating body, and a material discharge cone section connected to the bottom of the jacketed heating body; The heat exchange distribution section is provided with a heat exchange mechanism connected to the natural gas to acetylene solvent concentration system (3), and a distribution mechanism connected to the heat exchange mechanism; A scraping plate (17) and a spiral material pushing plate (18) are arranged below the scraping plate (17) in the jacketed heating body; The upper part of the jacket of the jacket-type heating body is provided with a superheated steam inlet for introducing superheated steam, and the lower part of the jacket is provided with a saturated steam condensate outlet; A spiral feeder (19) connected to a spiral push plate (18) is provided in the unloading cone section; A polymer delivery pipe (101) is connected to the discharge cone section, and a regeneration solvent delivery pipe (102) is connected between the condenser (2) and the natural gas acetylene solvent concentration system (3).

2. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 1, characterized in that: The heat exchange material distribution section is provided with a dirty solvent inlet (13) and a solvent vapor outlet (14); the natural gas acetylene solvent concentration system (3) is connected to the dirty solvent inlet (13); and the condenser (2) is connected to the solvent vapor outlet (14).

3. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 2, characterized in that: The heat exchange mechanism comprises a heat exchange coil (15) arranged in the heat exchange material distribution section and located below the solvent vapor output port (14), and the inlet end of the heat exchange coil (15) is connected to the dirty solvent inlet (13); The distribution mechanism comprises a centrifugal liquid collecting distributor (16) connected to the heat exchange mechanism and used for evenly distributing the contaminated solvent onto the heating surface of the inner wall of the jacketed heating body.

4. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 1, characterized in that: A variable frequency motor (11) for driving a material distribution mechanism, a film scraping plate (17), a spiral material pushing plate (18) and a spiral material feeder (19) is provided at the top of the heat exchange material distribution section.

5. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 4, characterized in that: The drive shaft of the variable frequency motor (11) is connected to a rotating shaft (12), and the rotating shaft (12) is respectively connected to a centrifugal liquid collecting distributor (16), a scraper plate (17), a spiral pusher plate (18) and a spiral feeder (19).

6. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 1, characterized in that: The polymer external delivery pipe (101) is connected to an external incineration device (4); The regeneration solvent delivery pipe (102) is provided with a regeneration solvent pump (5) and a liquid level regulating valve (6).

7. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 1, characterized in that: The condenser (2) is connected to a non-condensable gas external transmission pipe (103) connected to an external incineration device (4), and a vacuum pump (7) is provided on the non-condensable gas external transmission pipe (103).

8. A natural gas acetylene device N-methylpyrrolidone contaminated solvent treatment system according to claim 1, characterized in that: The superheated steam inlet of the jacketed heating body is connected to a heating steam delivery pipe (104), and the saturated steam condensate outlet is connected to a steam condensate delivery pipe (105). The heating steam delivery pipe (104) is provided with a pressure regulating valve (PV), a pressure controller (PC) and a flow controller (FC) in sequence according to the steam flow direction; A temperature controller (TC) is arranged at the middle and lower part of the jacketed heating body, and the temperature controller (TC) over-controls the pressure / flow selection controller (8), and the signal of the pressure / flow selection controller (8) is connected to the pressure regulating valve (PV); A first liquid level controller (LC1) is provided on the unloading cone section and is connected to the frequency conversion motor (11) by signal.

9. A method for treating N-methylpyrrolidone contaminated solvent in a natural gas acetylene device, characterized in that: The method is carried out using any system according to claim 1-8.

10. The processing method according to claim 9, characterized in that: The method comprises the following steps: the contaminated solvent from the acetylene solvent concentration system of natural gas is fed into the heat exchange distribution section of the thin film evaporator, and heat is exchanged with the superheated solvent steam from the jacketed heating body in the heat exchange coil; and then enters the centrifugal liquid collecting distributor, and is evenly distributed to the heating wall surface of the jacketed heating body under the action of the centrifugal liquid collecting distributor; The scraper plate continuously and evenly scrapes the material on the heated wall surface into a liquid film of uniform thickness; after the scraper evaporation, the light components in the dirty solvent are heated and evaporated; As the light components with lower boiling points in the polluted solvent continue to evaporate, a viscous colloid polymer is formed in the lower area of ​​the jacketed heating body. The colloid polymer is pushed to the discharge cone section by the action of the spiral pusher, and then pushed out of the thin film evaporator by the action of the spiral feeder, and then sent to the external incineration equipment for treatment; The light components in the contaminated solvent are heated and evaporated, forming a superheated steam stream that rises. After recovering part of the heat in the heat exchange material section at the top of the thin film evaporator, it is discharged from the top of the thin film evaporator and enters the condenser for condensation and liquefaction. The liquefied regenerated solvent is sent back to the concentration process for recycling, and the light component non-condensable gas is sent to the incineration device for treatment.

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