Acetylene tail gas recovery system for BDO production

Abstract

The utility model relates to an acetylene recovery system, and specifically provides an acetylene tail gas recovery system for BDO production. The utility model system includes: a tail gas compressor, an acetylene absorption tower, an acetylene analysis tower, an NMP recovery tower and an economizer; wherein, the inlet at the lower part of the acetylene absorption tower is connected to the outlet of the tail gas compressor, the outlet at the bottom of the acetylene absorption tower is connected to the first inlet of the economizer, the first outlet of the economizer is connected to the inlet in the middle of the acetylene analysis tower, the outlet at the top of the acetylene analysis tower is connected to a condensing device, the bottoms of the acetylene analysis tower and the NMP recovery tower are respectively connected to the second inlet of the economizer, the second outlet of the economizer is connected to the inlet of the cooler, the outlet of the cooler is connected to the inlet of the upper part of the acetylene absorption tower, and the bottoms of the acetylene analysis tower and the NMP recovery tower are respectively connected to heating devices. The utility model system can not only recover high-concentration acetylene but also improve the utilization rate of energy.

Description

Technical Field

[0001] The utility model relates to an acetylene recovery system, and specifically provides an acetylene tail gas recovery system for BDO production. Background Art

[0002] 1,4-Butanediol (BDO) is a basic organic chemical raw material and fine chemical raw material that plays an important role in the chemical industry. It has a wide range of applications and can be used to prepare vinyl chloride, polyvinyl chloride (PVC) and acetaldehyde. Due to its importance in industrial production, the preparation process of BDO has received extensive attention and research. The most commonly used method in industry is the Reppe method, also known as the acetylene aldehyde method. This method uses bismuth-containing acetylene copper complex as a catalyst. The bismuth-containing acetylene copper complex is adsorbed on a carrier. Acetylene reacts with formaldehyde aqueous solution to generate 1,4-butynediol and releases heat.

[0003] In order to ensure that the impact of the production process on the environment is minimized and production costs are reduced, adding acetylene tail gas recovery equipment has become an important choice for related production companies. However, the traditional treatment method is to directly discharge the tail gas (acetylene content 80%) of the production unit into the flare system for combustion. This practice not only wastes precious raw material resources, but also has an adverse impact on the environment. Therefore, the development and application of more efficient tail gas recovery technology to achieve the recovery and reuse of acetylene gas is of great significance to improving production efficiency and protecting the environment. Utility Model Content

[0004] In order to overcome the above defects, the utility model proposes an acetylene tail gas recovery system for BDO production, which can not only recover high-concentration acetylene but also improve the utilization rate of energy.

[0005] In a first aspect, the utility model provides an acetylene tail gas recovery system for BDO production, comprising: a tail gas compressor, an acetylene absorption tower, an acetylene decomposition tower, an NMP recovery tower and an economizer; wherein, the inlet of the tail gas compressor is used to be connected to the outlet of a BDO production device, the inlet of the lower part of the acetylene absorption tower is connected to the outlet of the tail gas compressor, the outlet of the bottom of the acetylene absorption tower is connected to the first inlet of the economizer, the first outlet of the economizer is connected to the inlet of the middle part of the acetylene decomposition tower, the outlet of the top of the acetylene decomposition tower is connected to a condensing device, the outlet of the condensing device is connected to a first reflux tank, the outlet of the first reflux tank is respectively connected to the upper part of the acetylene decomposition tower and the middle part of the NMP recovery tower, the bottoms of the acetylene decomposition tower and the NMP recovery tower are respectively connected to the second inlet of the economizer, the second outlet of the economizer is connected to the inlet of a cooler, the outlet of the cooler is connected to the inlet of the upper part of the acetylene absorption tower, and the bottoms of the acetylene decomposition tower and the NMP recovery tower are respectively connected to the second inlet of the economizer, the second outlet of the economizer is connected to the inlet of a cooler, the outlet of the cooler is connected to the inlet of the upper part of the acetylene absorption tower, and the bottoms of the acetylene decomposition tower and the NMP recovery tower are respectively connected to heating devices.

[0006] Furthermore, a distributor is provided inside the acetylene absorption tower, wherein the distributor comprises: a liquid receiving tray provided at the upper part of the acetylene absorption tower and spraying components evenly distributed on the liquid receiving tray, wherein each spraying component comprises: an overflow pipe, a vent pipe and a nozzle for spraying downwards connected to the liquid receiving tray;

[0007] The overflow pipe and the vent pipe are both located on the upper surface of the liquid receiving pan, the overflow pipe is sleeved on the outside of the vent pipe, the nozzle is connected to the liquid receiving pan between the overflow pipe and the vent pipe, and the liquid outlet of the nozzle is located below the liquid receiving pan.

[0008] Furthermore, in each spray assembly, the height of the overflow pipe is lower than the height of the ventilation pipe.

[0009] Furthermore, the economizer comprises a first cavity, a second cavity and a third cavity which are connected in sequence; wherein a plurality of spirally twisted tubes for heat exchange are arranged in the second cavity, and the plurality of spirally twisted tubes are arranged at intervals;

[0010] Two ends of the spirally twisted tube are respectively connected to the first cavity and the third cavity.

[0011] Further, the first inlet and the first outlet are respectively arranged on both sides of the second cavity, the second inlet is connected to the third cavity, and the second outlet is connected to the first cavity.

[0012] Furthermore, the system further comprises: a tail gas separation tank, wherein the inlet of the tail gas separation tank is connected to the outlet of the tail gas compressor, and the outlet of the tail gas separation tank is connected to the inlet of the lower part of the acetylene absorption tower.

[0013] Furthermore, the condensing device comprises: a partial condenser and a full condenser connected in sequence, wherein the inlet of the partial condenser is connected to the top of the acetylene analysis tower, and the outlets of the partial condenser and the full condenser are respectively connected to the inlet of the first reflux tank.

[0014] Furthermore, the bottom of the acetylene analysis tower is connected to a first reboiler, and the bottom of the NMP recovery tower is connected to a second reboiler.

[0015] Furthermore, a condenser is connected to the top of the NMP recovery tower, an outlet of the condenser is connected to a second reflux tank, and a bottom of the second reflux tank is connected to an inlet at an upper portion of the NMP recovery tower.

[0016] Furthermore, the outlet of the first reflux tank is connected to the inlet of a liquid pump, and the outlet of the liquid pump is respectively connected to the upper part of the acetylene analysis tower and the middle part of the NMP recovery tower.

[0017] The above one or more technical solutions of the utility model have at least one or more of the following beneficial effects:

[0018] The utility model can recover high-concentration acetylene and effectively recycle NMP through the tail gas compressor, the acetylene absorption tower, the acetylene analysis tower and the NMP recovery tower.

[0019] In the process of recovering acetylene, the utility model precools and preheats two liquids through the economizer, and greatly improves the utilization rate of energy through the interaction of the cold and hot liquids.

[0020] Under the action of the distributor, the acetylene absorption tower of the utility model can effectively and evenly disperse the NMP solution, improve the mixing effect and efficiency of the tail gas to be recovered and the NMP solution, and lay the foundation for subsequent analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the drawings are used to represent similar components, among which:

[0022] Figure 1 It is a schematic diagram of the main components of an acetylene tail gas recovery system for BDO production according to an embodiment of the utility model;

[0023] Figure 2 It is a schematic diagram of the main components of an acetylene tail gas recovery system for BDO production including a tail gas separation tank according to an embodiment of the utility model;

[0024] Figure 3is a schematic diagram of a first heat exchange path of an economizer according to an embodiment of the utility model;

[0025] Figure 4 is a schematic diagram of a second heat exchange path of an economizer according to an embodiment of the utility model;

[0026] Figure 5 is a side view of an economizer according to an embodiment of the utility model;

[0027] Figure 6 It is a structural schematic diagram of a distributor according to an embodiment of the utility model;

[0028] Figure 7 It is a schematic diagram of the top view of the structure of a distributor according to an embodiment of the utility model.

[0029] List of reference numerals:

[0030] 1: tail gas compressor; 2: acetylene absorption tower; 3: acetylene analysis tower; 4: NMP recovery tower; 5: economizer; 5-1 first inlet; 5-2 first outlet; 5-3 second inlet; 5-4 second outlet; 5-5 first cavity; 5-6 second cavity; 561 spiral twisted tube; 5-7 third cavity; 6 first reflux tank; 7 cooler; 8 distributor; 8-1 liquid receiving tray; 8-2 overflow pipe; 8-3 ventilation pipe; 9 partial condenser; 10 full condenser; 11 first reboiler; 12 second reboiler; 13 condenser; 14 second reflux tank; 15 tail gas separation tank; 16 static mixer; 17 acetylene product compressor; 18 NMP feed pipe; 19 liquid pump. DETAILED DESCRIPTION

[0031] Some embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0032] The utility model provides an acetylene tail gas recovery system for BDO production, more specifically, the utility model provides an acetylene tail gas recovery system for BDO production by acetylene-aldehyde process. Figure 1 , including: a tail gas compressor 1, an acetylene absorption tower 2, an acetylene analysis tower 3, an NMP recovery tower 4 and an economizer 5.

[0033] In the treatment process of the acetylene tail gas recovery system of the utility model, the tail gas to be treated is discharged from the outlet of the BDO production device. First, the tail gas to be treated needs to be sent to the tail gas compressor 1 for pressurization operation. The tail gas after pressurization will then be input into the acetylene absorption tower 2, in which the tail gas will be fully mixed with the NMP (N-methylpyrrolidone) solution sprayed from the top of the tower. The mixed gas and solution will further enter the acetylene analysis tower 3, where the analysis process is carried out to separate the two substances NMP and acetylene. In order to achieve the recycling of NMP, the NMP mixed solution that is not completely purified in the acetylene analysis tower 3 is further refined and purified in the NMP recovery tower 4. In addition, in order to ensure that the energy in the entire tail gas treatment process is efficiently utilized, a specific heat exchange is carried out in the economizer 5, which can minimize the waste of energy and improve the economy and environmental protection of the entire system.

[0034] The tail gas recovery process of the present invention is described in detail below in combination with the process steps and the structure of the system of the present invention.

[0035] S1, the inlet of the tail gas compressor 1 is used to be connected to the outlet of the BDO production device. The tail gas compressor 1 is connected to the BDO production device. The tail gas generated by the BDO production device mainly contains acetylene to be extracted and nitrogen. Oxygen or air is not allowed to be mixed into the tail gas because of safety hazards. The tail gas generated by the BDO production device is input into the tail gas compressor 1 to increase the pressure of the acetylene tail gas to 2.5 Bar.

[0036] In one embodiment, referring to Figure 2 The system further includes: a tail gas separation tank 15, in which a Raschig ring filler is arranged to separate a small amount of water. The inlet of the tail gas separation tank 15 is connected to the outlet of the tail gas compressor 1, and the outlet of the tail gas separation tank 15 is connected to the inlet of the lower part of the acetylene absorption tower 2. In this way, the acetylene tail gas from the BDO device increases the pressure of the acetylene tail gas to 2.5 Bar through the tail gas compressor 1, and a small amount of water in the acetylene tail gas is separated and discharged through the tail gas separation tank 15. The pressurized dry acetylene passes through the acetylene absorption tower 2 to absorb the acetylene in the acetylene tail gas using NMP as a solvent, and then the acetylene in the NMP solution is analyzed by the acetylene analysis tower 3, and the NMP is recovered by the NMP recovery tower 4 to achieve the reuse of NMP.

[0037] S2, the inlet at the lower part of the acetylene absorption tower 2 is connected to the outlet of the tail gas compressor 1. The tail gas pressurized by the tail gas compressor 1 is discharged from the outlet of the tail gas compressor 1 and enters the acetylene absorption tower 2 from the lower part of the acetylene absorption tower 2. The acetylene absorption tower 2 is a packed tower used to absorb acetylene in the acetylene tail gas. The acetylene absorption tower 2 recovers acetylene under the condition of 2.5Bar. During recovery, NMP is used as a solvent to spray downward from the upper part of the tower. The tail gas to be treated runs from bottom to top. The NMP solvent interacts with the acetylene tail gas in reverse to absorb the acetylene in the acetylene tail gas. After acetylene is recovered, the tail gas basically has nitrogen remaining. The nitrogen that is not absorbed at the top of the tower in the acetylene absorption tower 2 is discharged into the flare from the top of the tower, and the bottom liquid is an NMP solution enriched with acetylene.

[0038] S3, in the utility model, the bottom outlet of the acetylene absorption tower 2 is designed to be connected to the first inlet 5-1 of the economizer 5. This connection method ensures that the fluid discharged from the bottom of the acetylene absorption tower 2 can smoothly enter the economizer 5. As an efficient heat exchange device, the main function of the economizer 5 is to exchange heat. When the bottom liquid of the acetylene absorption tower 2 passes through the economizer 5, it absorbs heat from the economizer 5 and is heated. The heated bottom liquid is discharged from the first outlet 5-2 of the economizer 5 to the acetylene analysis tower 3, and enters from the inlet in the middle thereof. Such a design not only optimizes the utilization efficiency of thermal energy, but also ensures the continuity and stability of the entire system.

[0039] S4, the acetylene analysis tower 3 is a packed tower with two-stage packing, and a heating device is connected to the bottom of the acetylene analysis tower 3 for heating the acetylene analysis tower 3. Specifically, a first reboiler 11 is connected to the bottom of the acetylene analysis tower 3, and the tower heat provided by the heating device is provided by the reboiler. The bottom liquid of the acetylene absorption tower 2 is preheated by the economizer 5, enters the acetylene analysis tower 3, is heated at the bottom of the tower and condensed at the top of the tower. The outlet at the top of the acetylene analysis tower 3 is connected to a condensing device.

[0040] The main components of the top vapor phase of the acetylene analysis tower 3 are acetylene, NMP, water, etc. The outlet of the condensing device is connected to a first reflux tank 6 for collecting condensate. The outlets of the first reflux tank 6 are respectively connected to the upper part of the acetylene analysis tower 3 and the middle part of the NMP recovery tower 4. The destination of the condensate collected in the first reflux tank 6 is divided into two routes, one route is to flow into the upper part of the acetylene analysis tower 3, which is used for reflux; the other route is to flow to the middle part of the NMP recovery tower 4, which is used for downstream feeding. As a result, part of the condensate collected in the first reflux tank 6 flows into the acetylene analysis tower 3, and the other part flows into the NMP recovery tower 4.

[0041] In one embodiment, the outlet of the first reflux tank 6 is connected to the inlet of the liquid pump 19, and the outlet of the liquid pump 19 is respectively connected to the upper part of the acetylene analysis tower 3 and the middle part of the NMP recovery tower 4. The first reflux tank 6 transports part of the condensate in the first reflux tank 6 to the acetylene analysis tower 3 and the other part to the NMP recovery tower 4 through the pumping action of the liquid pump 19. A control valve for controlling the flow rate is provided on the delivery pipeline between the first reflux tank 6 and the acetylene analysis tower 3, and a control valve for controlling the flow rate is also provided on the delivery pipeline between the first reflux tank 6 and the NMP recovery tower 4.

[0042] In one embodiment, the condensing device comprises: a partial condenser 9 and a full condenser 10 connected in sequence, wherein the inlet of the partial condenser 9 is connected to the top of the acetylene analysis tower 3, and the outlets of the partial condenser 9 and the full condenser 10 are respectively connected to the inlet of the first reflux tank 6. In the partial condenser 9 and the full condenser 10, the partial condenser 9 uses cooling water as the cooling medium, and the full condenser 10 uses chilled water as the cooling medium. The NMP condensed by the partial condenser 9 and the full condenser 10 is collected in the first reflux tank 6, partially refluxed to the upper part of the acetylene analysis tower 3 by the reflux pump of the acetylene analysis tower, and partially sent to feed the NMP recovery tower 4; the uncondensed gas in the condensing device is the acetylene product with a purity of 98.01% analyzed, which is sent to the BDO device for reuse through the acetylene product compressor 17. The bottom liquid of the acetylene analysis tower 3 is the NMP solution after analysis, 100% pure NMP, which is pumped to the economizer 5 through the bottom liquid of the acetylene analysis tower 3, specifically, transported to the second inlet 5-3 of the economizer 5.

[0043] S4, the middle inlet of NMP recovery tower 4 receives the NMP mixed solution output from acetylene analysis tower 3, specifically, the middle inlet of NMP recovery tower 4 receives the NMP mixed solution from the first reflux tank 6, in NMP recovery tower 4, the NMP in the NMP solution after acetylene analysis tower 3 is further recovered to remove a small amount of unanalyzed acetylene, methanol and water. The NMP recovery tower 4 is a packed tower with two-stage packing, and the tower is maintained at an absolute pressure of 85-90mmHg by the NMP recovery tower vacuum system. The bottom of NMP recovery tower 4 is connected with a heating device, specifically, the bottom of the NMP recovery tower 4 is connected with a second reboiler 12, and the tower heat of NMP recovery tower 4 is provided by the second reboiler 12 of NMP recovery tower, and the top condensate from the acetylene analysis tower 3 is discharged from the first reflux tank 6, and a part is fed from the middle of NMP recovery tower 4, heated at the bottom of NMP recovery tower 4, and condensed at the top of NMP recovery tower 4. The bottom of the NMP recovery tower 4 is the NMP solvent from which impurities have been removed, and is pumped from the bottom of the NMP recovery tower to the economizer 5 , specifically, from the second inlet 5 - 3 of the economizer 5 .

[0044] In one embodiment, the top of the NMP recovery tower 4 is connected to a condenser 13, the outlet of the condenser 13 is connected to a second reflux tank 14, the bottom of the second reflux tank 14 is connected to the inlet of the upper part of the NMP recovery tower 4, the condenser 13 uses cooling water as a cooling medium, and the condensed liquid is collected in the second reflux tank 14, and partially refluxed to the upper part of the NMP recovery tower 4 by the NMP recovery tower reflux pump, and the remaining impurities containing a small amount of acetylene and methanol are sent out to be incinerated outside the boundary. The non-condensable gas of the condenser 13 mainly includes water, a small amount of acetylene and methanol, etc., which are sent to the torch through the vacuum system of the NMP recovery tower.

[0045] In one embodiment, the utility model also includes a control valve on the connecting pipeline, which is used to control the gas / liquid flow rate of the pipeline. Figure 2 , but not limited to, control valves are respectively provided at the following locations:

[0046] 1. A control valve is provided on the connecting pipeline between the tail gas separation tank and the inlet at the lower part of the acetylene absorption tower 2.

[0047] 2. A control valve is provided on the discharge pipeline at the top of the acetylene absorption tower 2.

[0048] 3. A control valve is provided on the connecting pipeline between the bottom of the acetylene absorption tower 2 and the economizer 5.

[0049] 4. A control valve is provided on the NMP feed pipe 18.

[0050] 5. A control valve is provided on the cooler 7 and on the pipeline between the cooler 7 and the static mixer 16.

[0051] 6. A control valve is provided on the pipeline between the second inlet 5 - 3 of the economizer 5 and the bottom of the acetylene analysis tower 3 .

[0052] 7. A control valve is provided on the first reboiler 11.

[0053] 8. A control valve is provided on the pipeline between the liquid pump 19 and the upper part of the acetylene analysis tower 3.

[0054] 9. A control valve is provided on the pipeline between the liquid pump 19 and the NMP recovery tower 4.

[0055] 10. The partial condenser 9 and / or the full condenser 10 is provided with a control valve.

[0056] 11. The acetylene product compressor 17 is provided with a control valve.

[0057] 12. The pipeline between the bottom of the NMP recovery tower 4 and the economizer 5 is provided with a control valve.

[0058] 13. The second reboiler 12 is provided with a control valve.

[0059] 14. Control valves are provided on the input and output pipes of the condenser 13.

[0060] 15. A control valve is provided on the connecting pipe between the first reflux tank 6 and the NMP recovery tower 4, and a control valve is provided on the connecting pipe between the first reflux tank 6 and the acetylene analysis tower 3.

[0061] 16. A control valve is provided on the discharge pipe for discharging impurities connected to the bottom or lower part of the second reflux tank 14, and a control valve is provided on the connecting pipe between the second reflux tank 14 and the NMP recovery tower 4.

[0062] Figure 2 In the schematic diagram of the control valve, FC represents flow control, LC represents liquid level control, TC represents temperature control, and the dotted line represents instrument signal transmission.

[0063] In one embodiment, the utility model further includes a delivery pump for delivering materials, wherein the materials are gaseous and / or liquid:

[0064] A delivery pump is provided between the bottom of the acetylene absorption tower 2 and the economizer 5 .

[0065] A delivery pump is provided between the bottom of the acetylene analysis tower 3 and the economizer 5 .

[0066] A delivery pump is provided between the bottom of the NMP recovery tower 4 and the economizer 5 .

[0067] The bottom of the first reflux tank 6 is connected to the acetylene analysis tower 3 and the NMP recovery tower 4 respectively through a delivery pump, namely a liquid pump 19.

[0068] Between the bottom of the second reflux tank 14 and the NMP recovery tower 4.

[0069] The heat exchange structure of the economizer 5 of the present invention is described below.

[0070] The bottom of the acetylene analysis tower 3 and the bottom of the NMP recovery tower 4 are respectively connected to the second inlet 5-3 of the economizer 5, the second outlet 5-4 of the economizer 5 is connected to the inlet of the cooler 7, and the outlet of the cooler 7 is connected to the inlet of the upper part of the acetylene absorption tower 2.

[0071] There are two parts of cold and hot liquids interacting in the economizer 5. The tower bottom liquid of the acetylene analysis tower 3 and the NMP recovery tower 4 with higher temperature enters the economizer 5 from the second inlet 5-3 of the economizer 5. After heat exchange, when it is discharged from the second outlet 5-4 of the economizer 5, the temperature is reduced, which plays a role of precooling. Then it is cooled by the cooler 7 and enters the acetylene absorption tower 2. The tower bottom liquid discharged from the tower bottom of the acetylene absorption tower 2 has a lower temperature. After the tower bottom liquid of the acetylene absorption tower 2 enters from the first inlet 5-1 of the economizer 5, after heat exchange, when it is discharged from the first outlet 5-2 of the economizer 5, the temperature increases, which plays a role of preheating. In this way, the whole system makes full use of energy.

[0072] In one embodiment, the system further includes an NMP feed pipe 18, which is used to transport fresh NMP solution. As an energy-saving measure, the kettle liquid from the acetylene analysis tower 3 and the kettle liquid from the NMP recovery tower 4 are mixed and sent to the economizer 5, and then exchange heat energy with the NMP solution enriched with acetylene from the kettle of the acetylene absorption tower 2. After heat exchange, the solution discharged from the second outlet 5-4 of the economizer 5 is combined with the fresh NMP solvent (the fresh NMP solution is transported by the NMP feed pipe 18), and after the combination, they are input into the cooler 7 for cooling. The cooler 7 uses chilled water as the cooling medium. The cooled NMP solvent is sent to the top of the acetylene absorption tower 2 for feeding, and the absorption of acetylene by NMP is achieved at low energy consumption.

[0073] In one embodiment, the NMP solvent after cooling input from the cooler 7 is mixed evenly in the static mixer 16 to form a uniform system. After the mixing action of the static mixer 16, it is input to the inlet at the top of the acetylene absorber 2. The inlet at the top of the acetylene absorber 2 is connected to the outlet of the static mixer 16.

[0074] The following describes the optimized structure of the economizer of the utility model.

[0075] In one embodiment, referring to Figure 3 and Figure 4 The economizer 5 includes a first cavity 5-5, a second cavity 5-6 and a third cavity 5-7 which are connected in sequence; wherein a plurality of spirally twisted tubes 561 for heat exchange are arranged in the second cavity 5-6, and the plurality of spirally twisted tubes are arranged at intervals.

[0076] The two ends of the spirally twisted tube 561 are connected to the first cavity 5-5 and the third cavity 5-7 respectively.

[0077] Reference Figure 3 and Figure 4 The first cavity 5-5, the second cavity 5-6 and the third cavity 5-7 are arranged from left to right, and the cavities are connected.

[0078] The first cavity 5-5 and the third cavity 5-7 are hollow cavities. The second cavity 5-6 is a hollow structure and a plurality of spirally twisted tubes 561 are arranged therein. In an application scenario, the spirally twisted tubes 561 are arranged at intervals. Figure 5 The diagram is a schematic diagram of the distribution of the spirally twisted tube 561 on the side of the third cavity 5-7 from the right to the left. The spirally twisted tube 561 is a heat exchange tube, which is in a spiral shape, in other words, a flat tube shape twisted clockwise or counterclockwise.

[0079] In order to maximize the heat recovery without increasing the additional steam consumption, economizer 5 adopts a highly efficient compact heat exchanger. The heat exchanger is specially processed on the basis of ordinary light tube arrays. The arrays are spirally twisted, and the turbulence intensity of the fluid in the twisted arrays is greatly increased, which enhances the mass transfer and heat transfer of the fluid. In the spiral flow process, a secondary swirl perpendicular to the mainstream direction is also generated, which increases the synergy of the velocity field and the temperature field, thereby improving the heat transfer performance in the tube. In the spiral twisted tube, the Reynolds number is 8000≤Re≤12000. Due to the self-supporting structure of the spiral twisted tube, a spiral channel is formed between the tubes. The fluid periodically changes its speed and direction in the channel due to the centrifugal force, which enhances the longitudinal mixing of the fluid. At the same time, the fluid forms a wake that separates from the tube wall after passing through the contact point, which increases the turbulence of the fluid and greatly improves the heat transfer efficiency of the heat exchanger.

[0080] Since the spiral twisted flat tube heat exchanger has no baffles, there is no dead zone in the shell. Compared with the traditional bow baffle heat exchanger, the anti-scaling performance is greatly improved and it is easy to maintain and clean.

[0081] In one embodiment, the first inlet 5-1 and the first outlet 5-2 are respectively arranged on both sides of the second cavity 5-6, the second inlet 5-3 is connected to the third cavity 5-7, and the second outlet 5-4 is connected to the first cavity 5-5.

[0082] In one embodiment, the first inlet 5-1 is disposed at the lower side of the second cavity 5-6, and the first outlet 5-2 is disposed at the upper side of the second cavity 5-6. The second outlet 5-4 is disposed at the upper side of the first cavity 5-5, and the second inlet 5-3 is disposed at the lower side of the third cavity 5-7.

[0083] Heat exchange first way: reference Figure 3The liquid entering from the second inlet 5-3 enters the third cavity 5-7. Since the right end of each spiral twisted tube 561 is connected to the third cavity 5-7, the liquid in the third cavity 5-7 enters the left end of the spiral twisted tube 561 from the right end of each spiral twisted tube 561, then enters the first cavity 5-5, and finally is discharged from the second outlet 5-4. After the liquid passes through the heat exchange of the economizer 5, the liquid temperature becomes lower, which plays a role of precooling. Figure 3 The direction of the arrow in the middle indicates the direction of liquid flow.

[0084] Heat exchange second way: reference Figure 4 The liquid entering from the first inlet 5-1 enters the second cavity 5-6, passes through the outer wall of each spirally twisted tube 561, and then is discharged from the first outlet 5-2. After the liquid passes through the heat exchange of the economizer 5, the liquid temperature becomes higher, which plays a role of preheating. Figure 4 The direction of the arrow in the middle indicates the direction of liquid flow.

[0085] The following describes the optimized structure of the acetylene absorption tower of the utility model.

[0086] In one embodiment, in order to enhance the absorption effect of NMP on acetylene, a distributor 8 is provided inside the acetylene absorption tower 2. Figure 6 and Figure 7 , wherein the distributor 8 includes: a liquid receiving pan 8-1 arranged on the upper part of the acetylene absorption tower 2 and spray components evenly distributed on the liquid receiving pan 8-1, wherein each spray component includes: an overflow pipe 8-2, a vent pipe 8-3 and a nozzle 8-4 for spraying downwards arranged on the liquid receiving pan 8-1.

[0087] Adjacent spray components are spaced apart.

[0088] The overflow pipe 8-2, the vent pipe 8-3 and the nozzle 8-4 are all connected to the liquid receiving pan 8-1.

[0089] The nozzle 8-4 can spray downward to achieve downward spraying of the NMP solution.

[0090] The specific structure is:

[0091] The liquid receiving pan 8-1 is concave and is arranged to fit the inner wall of the acetylene absorption tower 2. The overflow pipe 8-2 and the vent pipe 8-3 are both located on the upper surface of the liquid receiving pan 8-1, and the overflow pipe 8-2 is sleeved on the outside of the vent pipe 8-3, and a gap or a spacing space is provided between the overflow pipe 8-2 and the vent pipe 8-3. The nozzle 8-4 is connected to the liquid receiving pan 8-1 between the overflow pipe 8-2 and the vent pipe 8-3, and the liquid outlet of the nozzle 8-4 is located below the liquid receiving pan 8-1.

[0092] In one embodiment, in each spray assembly, the height of the overflow pipe 8-2 is lower than the height of the ventilation pipe 8-3.

[0093] The NMP solution enters the acetylene absorber 2 from the inlet at the top of the acetylene absorber 2, and the NMP solution falls on the liquid receiving pan 8-1. As more and more NMP solution enters the acetylene absorber 2, the liquid level of the liquid receiving pan 8-1 becomes higher and higher. When the liquid level is higher than the height of the overflow pipe 8-2, the NMP solution on the liquid receiving pan 8-1 overflows through the overflow pipe 8-2 and enters the liquid receiving pan 8-1 between the overflow pipe 8-2 and the vent pipe 8-3. Since a plurality of nozzles 8-4 are arranged on the surface of the liquid receiving pan 8-1 between the overflow pipe 8-2 and the vent pipe 8-3, and the liquid outlet of the nozzle 8-4 is arranged downward, the NMP solution enters the nozzle 8-4 and sprays downward. Since the height of the vent pipe 8-3 set in the overflow pipe 8-2 is higher, the NMP solution will not flow into the vent pipe 8-3, and the vent pipe 8-3 plays a role in making the NMP solution flow smoothly.

[0094] The utility model acetylene absorption tower can achieve effective dispersion of NMP solution through the ingenious design and application of the distributor. This dispersion is uniform, thereby significantly improving the mixing effect between the tail gas to be recovered and the NMP solution. This efficient mixing not only enhances the working efficiency of the absorption tower, but also lays the foundation for the subsequent analysis process, ensuring the efficient operation of the entire recovery system.

[0095] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present invention, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0096] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An acetylene tail gas recovery system for BDO production, characterized in that: include: An exhaust gas compressor (1), an acetylene absorption tower (2), an acetylene analysis tower (3), an NMP recovery tower (4) and an economizer (5); wherein the inlet of the exhaust gas compressor (1) is used to be connected to the outlet of a BDO production device, the inlet of the lower part of the acetylene absorption tower (2) is connected to the outlet of the exhaust gas compressor (1), the outlet at the bottom of the acetylene absorption tower (2) is connected to the first inlet (5-1) of the economizer (5), the first outlet (5-2) of the economizer (5) is connected to the inlet at the middle part of the acetylene analysis tower (3), the outlet at the top of the acetylene analysis tower (3) is connected to a condensing device, and the The outlet of the condensing device is connected to a first reflux tank (6), the outlet of the first reflux tank (6) is respectively connected to the upper part of the acetylene analysis tower (3) and the middle part of the NMP recovery tower (4), the bottoms of the acetylene analysis tower (3) and the NMP recovery tower (4) are respectively connected to the second inlet (5-3) of the economizer (5), the second outlet (5-4) of the economizer (5) is connected to the inlet of a cooler (7), the outlet of the cooler (7) is connected to the inlet of the upper part of the acetylene absorption tower (2), and the bottoms of the acetylene analysis tower (3) and the NMP recovery tower (4) are respectively connected to heating devices.

2. The system according to claim 1, characterized in that A distributor (8) is arranged inside the acetylene absorption tower (2), wherein the distributor (8) comprises: a liquid receiving tray (8-1) arranged at the upper part of the acetylene absorption tower (2) and spray components evenly distributed on the liquid receiving tray (8-1), wherein each spray component comprises: an overflow pipe (8-2) connected to and arranged on the liquid receiving tray (8-1), a vent pipe (8-3) and a nozzle (8-4) for spraying downwards; The overflow pipe (8-2) and the vent pipe (8-3) are both located on the upper surface of the liquid receiving pan (8-1); the overflow pipe (8-2) is sleeved on the outside of the vent pipe (8-3); the nozzle (8-4) is connected to the liquid receiving pan (8-1) between the overflow pipe (8-2) and the vent pipe (8-3); and the liquid outlet of the nozzle (8-4) is located below the liquid receiving pan (8-1).

3. The system according to claim 2, characterized in that In each spray assembly, the height of the overflow pipe (8-2) is lower than the height of the ventilation pipe (8-3).

4. The system according to claim 1, characterized in that The economizer (5) comprises a first cavity (5-5), a second cavity (5-6) and a third cavity (5-7) which are connected in sequence; wherein a plurality of spiral twisted tubes (561) for heat exchange are arranged in the second cavity (5-6), and the plurality of spiral twisted tubes are arranged at intervals; and the two ends of the spiral twisted tubes (561) are respectively connected to the first cavity (5-5) and the third cavity (5-7).

5. The system according to claim 4, characterized in that The first inlet (5-1) and the first outlet (5-2) are respectively arranged on both sides of the second cavity (5-6), the second inlet (5-3) is connected to the third cavity (5-7), and the second outlet (5-4) is connected to the first cavity (5-5).

6. The system according to claim 1, characterized in that The system further comprises: a tail gas separation tank (15), wherein the inlet of the tail gas separation tank (15) is connected to the outlet of the tail gas compressor (1), and the outlet of the tail gas separation tank (15) is connected to the inlet of the lower part of the acetylene absorption tower (2).

7. The system according to claim 1, characterized in that The condensing device comprises: a partial condenser (9) and a full condenser (10) connected in sequence, wherein the inlet of the partial condenser (9) is connected to the top of the acetylene analysis tower (3), and the outlets of the partial condenser (9) and the full condenser (10) are respectively connected to the inlet of the first reflux tank (6).

8. The system according to claim 1, characterized in that The bottom of the acetylene analysis tower (3) is connected to a first reboiler (11), and the bottom of the NMP recovery tower (4) is connected to a second reboiler (12).

9. The system according to claim 1, characterized in that The top of the NMP recovery tower (4) is connected to a condenser (13), the outlet of the condenser (13) is connected to a second reflux tank (14), and the bottom of the second reflux tank (14) is connected to an inlet at the top of the NMP recovery tower (4).

10. The system according to claim 1, characterized in that The outlet of the first reflux tank (6) is connected to the inlet of a liquid pump (19), and the outlet of the liquid pump (19) is respectively connected to the upper part of the acetylene analysis tower (3) and the middle part of the NMP recovery tower (4).

Images