Method and device for improving light benzene feeding temperature through XS fraction waste heat recovery

Abstract

The invention provides a method and device for improving the light benzene feeding temperature through XS fraction waste heat recovery, and belongs to the technical field of chemical engineering. Comprising a pretreatment unit, a main switch valve, a three-way pipe and an electric control valve, the main switch valve is arranged on the right surface of the pretreatment unit, the three-way pipe is arranged at one end of the main switch valve, and the electric control valve is arranged at one end of the three-way pipe. By arranging the shell-and-tube heat exchanger module, after heat exchange of the device, XS fractions can be cooled through multi-layer and multi-length circulating water, the temperature of the XS fractions is reduced to an ideal temperature, and compared with an existing shell-and-tube heat exchanger that the XS fractions are cooled at a time through circulating water, the XS fraction cooling effect is poor, and the XS fractions are cooled at a time; compared with the prior art, the XS fraction cooling difficulty and the energy consumption of the circulating water are easily increased, and the XS fraction cooling effect is better through multi-layer and multi-length circulating water cooling of the shell-and-tube heat exchanger module, so that the XS fraction cooling difficulty is reduced to a certain extent, and the cooling energy consumption of the circulating water is also reduced.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering technology, and particularly relates to a method and device for recovering waste heat of XS fraction to increase the temperature of light benzene feedstock. Background Art

[0002] The XS fraction usually refers to an intermediate fraction with a certain distillation range and composition separated from a fractionating tower or other separation equipment in a specific process. It generally contains various hydrocarbon compounds and a small amount of impurities, and its specific composition and properties will vary due to factors such as raw material source and process conditions. The temperature of the XS fraction is relatively high, containing a certain amount of thermal energy, which has the value of recovery and utilization.

[0003] Although the existing use of waste heat recovery of XS fraction is relatively common, there are still certain drawbacks: First, most of the existing waste heat recovery of XS fraction relies on a shell-and-tube heat exchanger for heat exchange, with the raw material flowing through the tube side and the XS fraction flowing through the shell side. In this way, although the temperature of the raw material can be raised by using the high temperature of the XS fraction, the high temperature of the XS fraction needs to be cooled by circulating water in the shell-and-tube heat exchanger. Currently, most of the cooling using circulating water is a one-time direct cooling, which not only increases the difficulty of cooling the XS fraction by the shell-and-tube heat exchanger but also extremely easily increases the energy consumption of the circulating water. Second, the light benzene raw material in the existing shell-and-tube heat exchanger needs to be transported out of the shell-and-tube heat exchanger after being heated by the high temperature of the XS fraction. During the transportation process, the heat of the light benzene raw material will be lost to some extent. After the light benzene raw material with lost heat enters the hydrogenation unit, the hydrogenation unit still requires a large amount of heat, which means that the heating furnace needs to consume more raw material gas, and this also reduces the chemical production of the chemical reaction of the raw material gas to a certain extent. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and device for recovering waste heat of XS fraction to increase the temperature of light benzene feedstock to solve the problems that the existing circulating water used in the shell-and-tube heat exchanger has poor cooling effect and slow cooling speed, which increases the difficulty of cooling the XS fraction to a certain extent and increases the energy consumption of the circulating water, and that the existing light benzene raw material will have heat loss during transportation in the shell-and-tube heat exchanger after heat exchange, the hydrogenation unit still requires a large amount of heat, the heating furnace needs to consume more raw material gas, and thus reduces the chemical production of the chemical reaction of the raw material gas.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for recovering waste heat of XS fraction to increase the temperature of light benzene feedstock, comprising the following steps:

[0007] Step 1: Transport the acetic acid tail gas to the pretreatment unit, where it is transformed, compressed, and the carbon dioxide is adsorbed and removed, and then enters the hydrogen production unit. A very small part enters the air compressor for compression and is stored in the gas storage tank for convenient use in heating the furnace. The raw material gas in the hydrogen production unit is subjected to pressure swing adsorption again to purify the hydrogen concentration to 99.99%. The hydrogen purified for the first time enters the hydrogenation unit;

[0008] Step 2: The hydrogenation unit purifies and saturates light benzene and hydrogen, and the generated BTXS fraction is sent to the pre-distillation unit. After the BTXS fraction enters the pre-distillation unit, it is subjected to slightly positive pressure distillation to form the BT fraction at the top of the tower and the XS fraction at the bottom of the tower. The XS fraction enters the shell-and-tube heat exchanger module. At this time, the subsequent generated hydrogen and light benzene raw materials enter the shell-and-tube heat exchanger module to exchange heat with the XS fraction;

[0009] Step 3: After the light benzene raw material exchanges heat with the XS fraction in Step 2, use the heat absorption and heat preservation effect of the heat preservation module to perform heat preservation treatment on the light benzene raw material after heat exchange in the shell-and-tube heat exchanger module, so as to minimize the loss of heat of the light benzene raw material.

[0010] A device for recovering the waste heat of the XS fraction to increase the temperature of the light benzene feed. The right surface of the pretreatment unit is provided with a main switch valve. One end of the main switch valve is provided with a three-way pipe. One end of the three-way pipe is provided with an electric control valve. One end of the electric control valve is provided with a raw material gas delivery pipe. One end of the raw material gas delivery pipe is provided with an air compressor. One end of the air compressor is installed with a gas storage tank. The right side of the gas storage tank is installed with a pressure stabilizing valve. One end of the pressure stabilizing valve is installed with a heating furnace; the back of the heating furnace is provided with a heat transfer pipe. One end of the heat transfer pipe is provided with a hydrogenation unit. The upper surface of the hydrogenation unit is provided with a suction pump pipe group. The hydrogenation unit is installed with a shell-and-tube heat exchanger module through the suction pump pipe group. The surface of the shell-and-tube heat exchanger module is installed with a heat preservation module.

[0011] Optionally, the upper surface of the shell-and-tube heat exchanger module is provided with a hydrogen production suction pump pipe group. The shell-and-tube heat exchanger module is installed with a hydrogen production unit through the hydrogen production suction pump pipe group. The left side surface of the hydrogen production unit is provided with a hydrogen production unit valve. One end of the hydrogen production unit valve is installed with a three-way pipe.

[0012] Optionally, the lower surface of the shell-and-tube heat exchanger module is successively installed with an XS fraction inlet pipe and an XS fraction outlet pipe from left to right. The shell-and-tube heat exchanger module is installed with a bottom of the tower through the XS fraction inlet pipe. The top of the bottom of the tower is provided with a pre-distillation unit. The top of the pre-distillation unit is provided with a top of the tower. The surface of the bottom of the tower is provided with an XS fraction pipe. The bottom of the tower is installed with a pre-distillation unit through the XS fraction pipe. The surface of the pre-distillation unit is provided with a BT fraction pipe. The pre-distillation unit is installed with a top of the tower through the BT fraction pipe.

[0013] Optionally, a top suction pump pipe group is provided at the top of the tower top. An extraction distillation unit is installed on the tower top through the top suction pump pipe group. A pre-distillation unit connecting pipe is provided on the left surface of the pre-distillation unit. A hydrogenation unit is installed on the pre-distillation unit through the pre-distillation unit connecting pipe. One end of the XS fraction discharge pipe is installed with a tank body.

[0014] Optionally, the shell-and-tube heat exchanger module includes an upper heat exchanger. An upper surface left connection end and an upper surface right connection end are successively provided on the upper surface of the upper heat exchanger from left to right. The bottom of the upper heat exchanger is fixedly connected with an upper connection piece. An upper boron nitride ceramic is provided at the bottom of the upper connection piece. A middle graphene heat conducting sheet is provided at the bottom of the upper boron nitride ceramic.

[0015] Optionally, a bottom boron nitride ceramic is provided at the bottom of the middle graphene heat conducting sheet. A bottom connection piece is provided at the bottom of the bottom boron nitride ceramic. A heat conducting rod is provided at the bottom of the middle graphene heat conducting sheet. A bottom left heat exchanger is fixedly connected to the bottom of the bottom connection piece. A left support seat and a bottom left connection end are successively provided at the bottom of the bottom left heat exchanger from left to right.

[0016] Optionally, a left end connecting plate is provided on the right side of the bottom left heat exchanger. A left side circulating water cooler is provided on the right side of the left end connecting plate. A middle connecting plate is provided on the right side of the left side circulating water cooler. A middle circulating water cooler is provided on the right side of the middle connecting plate. A right end connecting plate is provided on the right side of the middle circulating water cooler. A right side circulating water cooler is provided on the right side of the right end connecting plate. An XS fraction electric control valve and a right support seat are successively provided at the bottom of the right side circulating water cooler from left to right.

[0017] Optionally, a jack is provided on the right side of the right side circulating water cooler. A sealing ring is installed on the inner wall of the jack. A temperature control machine is provided on the inner wall of the sealing ring. A data line is provided at the top of the temperature control machine. A PLC temperature controller is installed on the temperature control machine through the data line. Baffle plates are provided inside the left side circulating water cooler, the middle circulating water cooler and the right side circulating water cooler. Water inlet ends and water outlet ends are successively provided on the front surfaces of the left side circulating water cooler, the middle circulating water cooler and the right side circulating water cooler from left to right.

[0018] Optionally, the heat preservation module includes a daylighting mirror. A top connecting iron sheet is provided at the bottom of the daylighting mirror. A bolt base is fixedly connected to the surface of the top connecting iron sheet. A bottom arc connecting sleeve is provided at the bottom of the bolt base. The bottom arc connecting sleeve is threadedly connected to the bolt base through a connecting bolt. A black film layer is provided on the inner wall of the daylighting mirror. An endothermic graphene is provided on the inner wall of the black film layer. A heat transfer rod is provided at the bottom of the endothermic graphene. A heat preservation layer is provided at the bottom of the endothermic graphene. A heat conduction layer is provided at the bottom of the heat preservation layer. A threaded fastening ring is threadedly connected to the surface of the connecting bolt.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] In the above solution, by setting the shell-and-tube heat exchanger module, after heat exchange of the device, the XS fraction can be cooled by multi-layer and multi-length circulating water, and the temperature of the XS fraction can be reduced to an ideal temperature. Compared with the existing shell-and-tube heat exchanger that uses circulating water to cool the XS fraction once, resulting in poor cooling effect of the XS fraction and easy increase in the cooling difficulty of the XS fraction and the energy consumption of the circulating water, the device cools the XS fraction through multi-layer and multi-length circulating water of the shell-and-tube heat exchanger module, so that the cooling effect of the XS fraction is better, which reduces the cooling difficulty of the XS fraction to a certain extent and also reduces the cooling energy consumption of the circulating water.

[0021] By setting the heat preservation module, after the light benzene raw material of the device is heat exchanged, heat can be provided to the light benzene raw material during the transmission process, so that the heat of the light benzene raw material can be retained as much as possible. To a certain extent, this can ensure that the light benzene raw material enters the hydrogenation unit with sufficient heat, thereby reducing the use of the raw material gas by the heating furnace, and then enabling more raw material gas to be used for production, which increases the yield of the products after the chemical reaction to a certain extent. Description of the Drawings

[0022] The drawings incorporated herein and constituting a part of the specification illustrate embodiments of the present invention and, together with the specification, are further used to explain the principles of the present invention and enable those skilled in the relevant art to implement and use the present invention.

[0023] Figure 1 Schematic three-dimensional structure diagram of the method and device for recovering waste heat of the XS fraction to increase the light benzene feed temperature;

[0024] Figure 2 is Figure 1 Schematic enlarged view of the partial structure;

[0025] Figure 3 Schematic diagram of the shell-and-tube heat exchanger module of the method and device for recovering waste heat of the XS fraction to increase the light benzene feed temperature;

[0026] Figure 4For Figure 3 Partial enlarged schematic diagram of part A in

[0027] Figure 5 For Figure 3 Partial enlarged schematic diagram of part B in

[0028] Figure 6 For Figure 3 Partial enlarged schematic diagram of part C in

[0029] Figure 7 Internal plane schematic diagram of the shell-and-tube heat exchanger module of the method and device for recovering waste heat of XS fraction to increase the feed temperature of light benzene;

[0030] Figure 8 Schematic diagram of the heat insulation module of the method and device for recovering waste heat of XS fraction to increase the feed temperature of light benzene;

[0031] Reference numerals:

[0032] 1. Pretreatment unit; 2. Main switching valve; 3. Three-way pipe; 4. Electric control valve; 5. Raw material gas delivery pipe; 6. Air compressor; 7. Gas storage tank; 8. Pressure stabilizing valve; 9. Heating furnace; 10. Heat transfer pipe; 11. Hydrogenation unit; 12. Suction pump pipe group; 13. Shell-and-tube heat exchanger module; 1301. Upper heat exchanger; 1302. Left connection end on the upper surface; 1303. Right connection end on the upper surface; 1304. Upper connection piece; 1305. Upper boron nitride ceramic; 1306. Middle graphene heat conducting sheet; 1307. Bottom boron nitride ceramic; 1308. Bottom connection piece; 1309. Heat conducting rod; 1310. Left bottom heat exchanger; 1311. Left support seat; 1312. Left bottom connection end; 1313. Left end connection plate; 1314. Left circulating water cooler; 1315. Middle connection plate; 1316. Middle circulating water cooler; 1317. Right end connection plate; 1318. Right circulating water cooler; 1319. XS fraction electric control valve; 1320. Right support seat; 1321. Sealing ring; 1322. Temperature control machine; 1323. Data line; 1324. PLC temperature controller; 1325. Baffle plate; 1326. Water inlet end; 1327. Water outlet end; 14. Heat preservation module; 1401. Lighting mirror; 1402. Top connection iron sheet; 1403. Bolt base; 1404. Bottom arc connection sleeve; 1405. Black film layer; 1406. Heat-absorbing graphene; 1407. Heat transfer rod; 1408. Heat preservation layer; 1409. Heat conducting layer; 1410. Thread fastening ring; 15. Hydrogen production suction pump pipe group; 16. Hydrogen production unit; 17. Hydrogen production unit valve; 18. XS fraction inlet pipe; 19. XS fraction discharge pipe; 20. Tower bottom; 21. Pre-distillation unit; 22. Tower top; 23. XS fraction pipe; 24. BT fraction pipe; 25. Tower top suction pump pipe group; 26. Extractive distillation unit; 27. Pre-distillation unit connecting pipe; 28. Tank body.

[0033] As shown in the figure, in order to clearly show the structure of the embodiments of the present invention, specific structures and devices are marked in the figure. However, this is only for schematic purposes and is not intended to limit the present invention to this specific structure, device, and environment. Those of ordinary skill in the art can adjust or modify these devices and environments according to specific needs. Detailed implementation manners

[0034] The following describes in detail a method and device for recovering the waste heat of XS fraction to increase the light benzene feed temperature provided by the present invention in combination with the accompanying drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; moreover, the accompanying drawings are only for more specifically describing the embodiments and are not intended to specifically limit the present invention.

[0035] It should be noted that in the specification, references to "one embodiment", "an embodiment", "exemplary embodiments", "some embodiments", etc. indicate that the described embodiments may include a particular feature, structure, or characteristic, but not necessarily every embodiment includes that particular feature, structure, or characteristic. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, implementing such feature, structure, or characteristic in connection with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the relevant art.

[0036] Generally, terms can be understood, at least in part, from their use in context. For example, at least in part depending on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey a set of exclusive factors, but rather, at least in part depending on the context, can allow for the existence of other factors that may not be explicitly described.

[0037] It can be understood that the meanings of "on", "above", and "over" in the present invention should be construed in the broadest manner such that "on" not only means "directly on" something, but also includes the meaning of being "on" something with intervening features or layers therebetween, and "above" or "over" not only means "above" or "over" something, but also can include the meaning of being "above" or "over" something with no intervening features or layers therebetween.

[0038] Furthermore, spatial relative terms such as "under", "below", "lower", "above", "upper", etc. may be used herein for convenience of description to describe the relationship of one element or feature to another or other elements or features, as shown in the drawings. The spatial relative terms are intended to cover different orientations in the use or operation of the device in addition to the orientation depicted in the drawings. The device may be oriented in other ways, and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0039] As Figure 1 and Figure 2 shown, an embodiment of the present invention provides a method for recovering waste heat of the XS fraction to increase the temperature of the light benzene feed, including the following steps:

[0040] Step 1: Transport the acetic acid tail gas to the pretreatment unit, where it is transformed, compressed, and the carbon dioxide is adsorbed and removed, and then enters the hydrogen production unit. A very small part enters the air compressor for compression and is stored in the gas storage tank for convenient use in heating the heating furnace. The raw material gas in the hydrogen production unit is further purified by pressure swing adsorption to increase the hydrogen concentration to 99.99%. The hydrogen purified for the first time enters the hydrogenation unit;

[0041] Step 2: The hydrogenation unit purifies and saturates light benzene and hydrogen, and the generated BTXS fraction is sent to the pre-distillation unit. After the BTXS fraction enters the pre-distillation unit, it is distilled under slightly positive pressure to form the BT fraction at the top of the tower and the XS fraction at the bottom of the tower. The XS fraction enters the shell-and-tube heat exchanger module. At this time, the subsequent generated hydrogen and light benzene raw materials enter the shell-and-tube heat exchanger module to exchange heat with the XS fraction;

[0042] Step 3: After the light benzene raw material exchanges heat with the XS fraction in Step 2, use the heat absorption and heat preservation effect of the heat preservation module to perform heat preservation treatment on the light benzene raw material after heat exchange in the shell-and-tube heat exchanger module, so as to minimize the loss of heat of the light benzene raw material.

[0043] An apparatus for recovering the waste heat of the XS fraction to increase the temperature of the light benzene feed. The right surface of the pretreatment unit 1 is provided with a main switch valve 2. One end of the main switch valve 2 is provided with a three-way pipe 3. One end of the three-way pipe 3 is provided with an electric control valve 4. One end of the electric control valve 4 is provided with a raw material gas delivery pipe 5. One end of the raw material gas delivery pipe 5 is provided with an air compressor 6. One end of the air compressor 6 is installed with a gas storage tank 7. The right side of the gas storage tank 7 is installed with a pressure stabilizing valve 8. One end of the pressure stabilizing valve 8 is installed with a heating furnace 9;

[0044] The back surface of the heating furnace 9 is provided with a heat transfer pipe 10. One end of the heat transfer pipe 10 is provided with a hydrogenation unit 11. The upper surface of the hydrogenation unit 11 is provided with a suction pump pipe group 12. The hydrogenation unit 11 is installed with a shell-and-tube heat exchanger module 13 through the suction pump pipe group 12. The surface of the shell-and-tube heat exchanger module 13 is installed with a heat preservation module 14.

[0045] The upper surface of the shell-and-tube heat exchanger module 13 is provided with a hydrogen production suction pump pipe group 15. The shell-and-tube heat exchanger module 13 is installed with a hydrogen production unit 16 through the hydrogen production suction pump pipe group 15. The left side surface of the hydrogen production unit 16 is provided with a hydrogen production unit valve 17. One end of the hydrogen production unit valve 17 is installed with a three-way pipe 3.

[0046] The lower surface of the shell-and-tube heat exchanger module 13 is successively installed with an XS fraction inlet pipe 18 and an XS fraction discharge pipe 19 from left to right. The shell-and-tube heat exchanger module 13 is installed with a bottom 20 through the XS fraction inlet pipe 18. The top of the bottom 20 is provided with a pre-distillation unit 21. The top of the pre-distillation unit 21 is provided with a top 22. The surface of the bottom 20 is provided with an XS fraction pipe 23. The bottom 20 is installed with the pre-distillation unit 21 through the XS fraction pipe 23. The surface of the pre-distillation unit 21 is provided with a BT fraction pipe 24. The pre-distillation unit 21 is installed with the top 22 through the BT fraction pipe 24.

[0047] The top of the top 22 is provided with a top suction pump pipe group 25. The top 22 is installed with an extractive distillation unit 26 through the top suction pump pipe group 25. The left surface of the pre-distillation unit 21 is provided with a pre-distillation unit connecting pipe 27. The pre-distillation unit 21 is installed with a hydrogenation unit 11 through the pre-distillation unit connecting pipe 27. One end of the XS fraction discharge pipe 19 is installed with a tank 28.

[0048] The main switch valve 2 is installed on the right surface of the pretreatment unit 1 by bolts. The three-way pipe 3 is installed between the main switch valve 2 and the hydrogen production unit valve 17. The electric control valve 4 is installed at the bifurcated end of the three-way pipe 3 by bolts. The raw material gas delivery pipe 5 is installed on the air compressor 6 by bolts. The air compressor 6 is installed on the gas storage tank 7 by bolts. The pressure stabilizing valve 8 is installed between the gas storage tank 7 and the heating furnace 9 by bolts. The heat transfer pipe 10 is integrally connected to the heating furnace 9. One end of the heat transfer pipe 10 is installed on the hydrogenation unit 11 by bolts. The suction pump pipe group 12 is installed between the suction pump pipe group 12 and the shell-and-tube heat exchanger module 13 by bolts. The heat preservation module 14 is installed on the surface of the shell-and-tube heat exchanger module 13. The hydrogen production suction pump pipe group 15 is installed between the shell-and-tube heat exchanger module 13 and the hydrogen production unit 16 by bolts. The hydrogen production unit valve 17 is installed on the left surface of the hydrogen production unit 16 by bolts. The XS fraction inlet pipe 18 is installed between the shell-and-tube heat exchanger module 13 and the bottom 20 by bolts. The XS fraction discharge pipe 19 is installed between the tank 28 and the shell-and-tube heat exchanger module 13 by bolts. The pre-distillation unit 21 is integrally formed with the bottom 20. The top 22 and the pre-distillation unit 21 are integrally formed. The XS fraction pipe 23 is installed between the bottom 20 and the pre-distillation unit 21 by bolts. The BT fraction pipe 24 is installed between the pre-distillation unit 21 and the top 22 by bolts. The top suction pump pipe group 25 is installed between the top 22 and the extractive distillation unit 26 by bolts. The pre-distillation unit connecting pipe 27 is installed between the hydrogenation unit 11 and the pre-distillation unit connecting pipe 27 by bolts, and the assembly is completed.

[0049] In use, the acetic acid tail gas is transported into the pretreatment unit 1, where it is transformed, compressed, and the carbon dioxide is adsorbed and removed, and then enters the hydrogen production unit 16. A very small part enters the air compressor 6 for compression and then enters the gas storage tank 7 for storage, which is convenient for use in heating the heating furnace 9. The raw material gas in the hydrogen production unit 16 is again subjected to pressure swing adsorption to purify the hydrogen concentration to 99.99%. The hydrogen purified for the first time and the light benzene raw material enter the hydrogenation unit 11. The hydrogenation unit 11 purifies and saturates the light benzene and hydrogen, and the generated BTXS fraction is sent to the pre-distillation unit 21. After the BTXS fraction enters the pre-distillation unit 21, it is subjected to slightly positive pressure distillation, thereby forming the BT fraction at the top of the tower and the XS fraction at the bottom of the tower. The XS fraction enters the shell-and-tube heat exchanger module 13. At this time, the subsequently generated hydrogen and light benzene raw material enter the shell-and-tube heat exchanger module 13 to exchange heat with the XS fraction. After the heat exchange, the subsequently generated hydrogen and light benzene raw material still enter the hydrogenation unit 11 for chemical reaction. After the heat exchange, the XS fraction is cooled and then enters the tank body 28 for storage, completing the operation.

[0050] As Figures 3 to 7 shown, the shell-and-tube heat exchanger module 13 includes an upper heat exchanger 1301. On the upper surface of the upper heat exchanger 1301, a left connection end 1302 and a right connection end 1303 on the upper surface are arranged in sequence from left to right. The bottom of the upper heat exchanger 1301 is fixedly connected with an upper connection piece 1304. At the bottom of the upper connection piece 1304, there is an upper boron nitride ceramic 1305. At the bottom of the upper boron nitride ceramic 1305, there is a middle graphene heat conducting sheet 1306.

[0051] At the bottom of the middle graphene heat conducting sheet 1306, there is a bottom boron nitride ceramic 1307. At the bottom of the bottom boron nitride ceramic 1307, there is a bottom connection piece 1308. At the bottom of the middle graphene heat conducting sheet 1306, there is a heat conducting rod 1309. At the bottom of the bottom connection piece 1308, the bottom left end of the bottom left end heat exchanger 1310 is fixedly connected. On the bottom of the bottom left end heat exchanger 1310, a left support seat 1311 and a bottom left connection end 1312 are arranged in sequence from left to right.

[0052] On the right side of the bottom left end heat exchanger 1310, there is a left end connecting plate 1313. On the right side of the left end connecting plate 1313, there is a left side circulating water cooler 1314. On the right side of the left side circulating water cooler 1314, there is a middle connecting plate 1315. On the right side of the middle connecting plate 1315, there is a middle circulating water cooler 1316. On the right side of the middle circulating water cooler 1316, there is a right end connecting plate 1317. On the right side of the right end connecting plate 1317, there is a right side circulating water cooler 1318. At the bottom of the right side circulating water cooler 1318, an XS fraction electric control valve 1319 and a right support seat 1320 are arranged in sequence from left to right.

[0053] On the right side of the right - hand circulating water cooler 1318, there is a jack. An airtight ring 1321 is installed on the inner wall of the jack. A temperature control machine 1322 is provided on the inner wall of the airtight ring 1321. A data line 1323 is provided at the top of the temperature control machine 1322. The temperature control machine 1322 is installed with a PLC temperature controller 1324 through the data line 1323. Baffle plates 1325 are provided inside the left - hand circulating water cooler 1314, the middle circulating water cooler 1316, and the right - hand circulating water cooler 1318. Water inlet ends 1326 and water outlet ends 1327 are successively provided from left to right on the fronts of the left - hand circulating water cooler 1314, the middle circulating water cooler 1316, and the right - hand circulating water cooler 1318.

[0054] The left - hand connection end 1302 on the upper surface and the right - hand connection end 1303 on the upper surface are welded to the upper heat exchanger 1301. The upper connecting piece 1304 is welded between the upper heat exchanger 1301 and the upper boron nitride ceramic 1305. The middle graphene heat - conducting sheet 1306 is integrally connected to the bottom boron nitride ceramic 1307 and the upper boron nitride ceramic 1305. The bottom connecting piece 1308 is welded between the left - hand heat exchanger 1310 at the bottom and the bottom boron nitride ceramic 1307. The heat - conducting rod 1309 passes through the bottom boron nitride ceramic 1307 and is welded to the middle graphene heat - conducting sheet 1306. The left - hand support base 1311 and the left - hand connection end 1312 at the bottom are welded to the bottom of the left - hand heat exchanger 1310 at the bottom. The left - hand connecting plate 1313 is welded between the left - hand heat exchanger 1310 at the bottom and the left - hand circulating water cooler 1314. The middle connecting plate 1315 is welded between the left - hand circulating water cooler 1314 and the middle circulating water cooler 1316. The right - hand connecting plate 1317 is welded between the middle circulating water cooler 1316 and the right - hand circulating water cooler 1318. The XS fraction electric control valve 1319 is installed at the bottom of the right - hand circulating water cooler 1318 through bolts. The right - hand support base 1320 is welded to the bottom of the right - hand circulating water cooler 1318. An airtight ring 1321 is installed inside the jack. The temperature control machine 1322 is inserted into the right - hand circulating water cooler 1318 through the airtight ring 1321. The PLC temperature controller 1324 and the temperature control machine 1322 are connected through the data line 1323. Baffle plates 1325 are welded inside the left - hand circulating water cooler 1314, the middle circulating water cooler 1316, and the right - hand circulating water cooler 1318, and water inlet ends 1326 and water outlet ends 1327 are welded on the surfaces, completing the assembly.

[0055] During use, after the XS fraction enters the shell-and-tube heat exchanger module 13, it first enters the heat exchanger 1310 at the left end of the bottom and enters the left-side circulating water cooler 1314 through the left-end connecting plate 1313. At this time, the first-stage circulating water cooling is carried out. Then, the XS fraction enters the middle circulating water cooler 1316 through the middle connecting plate 1315. At this time, the second-stage circulating water cooling is carried out. Then, the XS fraction enters the right-side circulating water cooler 1318 through the right-end connecting plate 1317. The temperature controller 1322 detects the temperature of the XS fraction in the right-side circulating water cooler 1318. If the temperature reaches the required value, the third-stage circulating water cooling is not required, and the XS fraction control valve 1319 is opened to allow the XS fraction to enter the XS fraction discharge pipe 19 and then enter the tank body 28. If the temperature of the XS fraction is too high, the third-stage circulating water cooling is started in the right-side circulating water cooler 1318 to reduce the temperature to the desired temperature. When the XS fraction passes through the heat exchanger 1310 at the left end of the bottom, the left-side circulating water cooler 1314, the middle circulating water cooler 1316, and the right-side circulating water cooler 1318, the heat conduction rod 1309 at the bottom of the middle graphene heat conduction sheet 1306 passes through the bottom boron nitride ceramic 1307 and inserts into the XS fraction, conducting the heat in the XS fraction into the middle graphene heat conduction sheet 1306 and then transferring it to the light benzene raw material in the upper heat exchanger 1301 through the upper boron nitride ceramic 1305. Thus, the heat of the XS fraction is transferred to the light benzene raw material in the upper heat exchanger 1301, heating the light benzene raw material in the upper heat exchanger 1301. The water inlet end 1326 and the water outlet end 1327 can be connected to existing water inlet pipes and water outlet pipes, so no detailed description will be given here.

[0056] By setting up the shell-and-tube heat exchanger module 13, after heat exchange, the XS fraction can be cooled by multi-layer and multi-length circulating water to reduce its temperature to the desired temperature. Compared with the existing shell-and-tube heat exchanger that cools the XS fraction with circulating water only once, resulting in poor cooling effect of the XS fraction, increased difficulty in cooling the XS fraction, and higher energy consumption of the circulating water, this device cools the XS fraction through multi-layer and multi-length circulating water in the shell-and-tube heat exchanger module 13, achieving a better cooling effect for the XS fraction. To a certain extent, this reduces the difficulty of cooling the XS fraction and also reduces the cooling energy consumption of the circulating water.

[0057] Such as Figure 8As shown, the heat insulation module 14 includes a daylighting mirror 1401. A top connecting iron sheet 1402 is provided at the bottom of the daylighting mirror 1401. A bolt base 1403 is fixedly connected to the surface of the top connecting iron sheet 1402. A bottom arc connecting sleeve 1404 is provided at the bottom of the bolt base 1403. The bottom arc connecting sleeve 1404 is threadedly connected to the bolt base 1403 through a connecting bolt. A black film layer 1405 is provided on the inner wall of the daylighting mirror 1401. An endothermic graphene 1406 is provided on the inner wall of the black film layer 1405. A heat transfer rod 1407 is provided at the bottom of the endothermic graphene 1406. A heat insulation layer 1408 is provided at the bottom of the endothermic graphene 1406. A heat conduction layer 1409 is provided at the bottom of the heat insulation layer 1408. A threaded fastening ring 1410 is threadedly connected to the surface of the connecting bolt.

[0058] The top connecting iron sheet 1402 is integrally connected to the daylighting mirror 1401, and the bolt base 1403 is welded to the top connecting iron sheet 1402. The black film layer 1405 is adhered between the daylighting mirror 1401 and the endothermic graphene 1406. The endothermic graphene 1406 is adhered between the black film layer 1405 and the heat insulation layer 1408. The heat insulation layer 1408 is adhered between the endothermic graphene 1406 and the heat conduction layer 1409. One end of the heat transfer rod 1407 passes through the heat insulation layer 1408 and is welded to the top of the heat conduction layer 1409, and the other end is welded to the bottom of the endothermic graphene 1406. The assembled daylighting mirror 1401 is sleeved on the shell-and-tube heat exchanger module 13, then the bottom arc connecting sleeve 1404 is sleeved on the shell-and-tube heat exchanger module 13, and finally the daylighting mirror 1401 and the bottom arc connecting sleeve 1404 are connected by a connecting bolt. Then the threaded fastening ring 1410 is screwed onto the connecting bolt and tightened to complete the assembly.

[0059] During use, after the light benzene raw material in the upper heat exchanger 1301 exchanges heat with the XS fraction, in order to prevent the loss of heat of the light benzene raw material, at this time, the heat insulation module 14 is installed on the surface of the shell-and-tube heat exchanger module 13. At this time, the daylighting mirror 1401 of the heat insulation module 14 will gather sunlight, and the black film layer 1405 will gather and conduct the heat of the sunlight to the endothermic graphene 1406. At this time, the heat on the endothermic graphene 1406 is conducted to the heat conduction layer 1409 through the heat transfer rod 1407 passing through the heat insulation layer 1408, and the heat on the heat conduction layer 1409 is directly conducted to the surface of the upper heat exchanger 1301 of the shell-and-tube heat exchanger module 13 to provide heat for the upper heat exchanger 1301. The heat insulation layer 1408 can prevent the loss of heat of the light benzene raw material in the upper heat exchanger 1301, and at the same time continuously supply heat to the upper heat exchanger 1301 through the heat conduction layer 1409, and the upper heat exchanger 1301 supplies heat to the light benzene raw material to minimize the loss of heat of the light benzene raw material.

[0060] By setting up the heat preservation module 14, after the light benzene raw material of the device is heat-exchanged, heat can be provided to the light benzene raw material during the transmission process, so that the heat of the light benzene raw material can be retained as much as possible. To a certain extent, this can ensure that the light benzene raw material enters the hydrogenation unit 11 with sufficient heat, thereby reducing the use of the raw material gas by the heating furnace 9, and then enabling more raw material gas to be used for production, which increases the output of the products after the chemical reaction to a certain extent.

[0061] The working principle of the technical solution provided by the present invention is as follows:

[0062] First, the acetic acid tail gas is transported into the pretreatment unit 1, where it is transformed, compressed, and the carbon dioxide is adsorbed and removed, and then enters the hydrogen production unit 16. A very small part enters the air compressor 6 for compression and is stored in the gas storage tank 7 for convenient use in heating the heating furnace 9. The raw material gas in the hydrogen production unit 16 is subjected to pressure swing adsorption again to purify the hydrogen concentration to 99.99%, the hydrogen gas purified for the first time enters the hydrogenation unit 11. The hydrogenation unit 11 purifies and saturates light benzene and hydrogen gas, and the generated BTXS fraction is sent to the pre-distillation unit 21. After the BTXS fraction enters the pre-distillation unit 21, it undergoes slightly positive pressure distillation to form the BT fraction at the top of the column and the XS fraction at the bottom of the column. The XS fraction enters the shell-and-tube heat exchanger module 13. At this time, the subsequently generated hydrogen gas and light benzene raw materials enter the shell-and-tube heat exchanger module 13 to exchange heat with the XS fraction. After the XS fraction enters the shell-and-tube heat exchanger module 13, it first enters the bottom left heat exchanger 1310 and enters the left circulating water cooler 1314 through the left connecting plate 1313. At this time, the first circulating water cooling is carried out. Then the XS fraction enters the middle circulating water cooler 1316 through the middle connecting plate 1315. At this time, the second circulating water cooling is carried out. Then the XS fraction enters the right circulating water cooler 1318 through the right connecting plate 1317. The temperature controller 1322 detects the temperature of the XS fraction in the right circulating water cooler 1318. If the temperature reaches the required value, the third circulating water cooling is not required, and the XS fraction electric control valve 1319 is opened to make the XS fraction enter the XS fraction discharge pipe 19 and enter the tank 28. If the temperature of the XS fraction is too high, the third circulating water cooling is started in the right circulating water cooler 1318 to reduce the temperature to the ideal temperature. When the XS fraction passes through the bottom left heat exchanger 1310, the left circulating water cooler 1314, the middle circulating water cooler 1316, and the right circulating water cooler 1318, the heat conduction rod 1309 at the bottom of the middle graphene heat conducting sheet 1306 passes through the bottom boron nitride ceramic 1307 and inserts into the XS fraction, conducting the heat in the XS fraction into the middle graphene heat conducting sheet 1306 and through the upper boron nitride ceramic 1305 into the light benzene raw material in the upper heat exchanger 1301. Thus, the heat of the XS fraction is exchanged with the light benzene raw material in the upper heat exchanger 1301, heating the light benzene raw material in the upper heat exchanger 1301. After the light benzene raw material in the upper heat exchanger 1301 exchanges heat with the XS fraction, in order to prevent the loss of heat of the light benzene raw material, a heat preservation module 14 is installed on the surface of the shell-and-tube heat exchanger module 13 at this time. The light collecting mirror 1401 of the heat preservation module 14 at this time will gather sunlight, and the black film layer 1405 will gather and conduct the heat of the sunlight to the heat absorbing graphene 1406. At this time, the heat on the heat absorbing graphene 1406 is conducted to the heat conducting layer 1409 through the heat transfer rod 1407 passing through the heat preservation layer 1408, and the heat on the heat conducting layer 1409 is directly conducted to the surface of the upper heat exchanger 1301 of the shell-and-tube heat exchanger module 13, providing heat for the upper heat exchanger 1301. The heat preservation layer 1408 can prevent the loss of heat of the light benzene raw material in the upper heat exchanger 1301, and at the same time continuously supply heat to the upper heat exchanger 1301 through the heat conducting layer 1409. The upper heat exchanger 1301 supplies heat to the light benzene raw material to minimize the loss of heat of the light benzene raw material.

[0063] The present invention encompasses any alternatives, modifications, equivalent methods, and solutions that are made within the spirit and scope of the present invention. For the purpose of enabling the public to have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention. However, those skilled in the art can fully understand the present invention even without the description of these details. In addition, well-known methods, processes, procedures, components, and circuits are not described in detail in order to avoid unnecessary confusion to the essence of the present invention.

[0064] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for recovering waste heat from XS fraction to increase the feed temperature of light benzene, characterized in that: The following steps are involved: Step 1: The acetic acid tail gas is transported to the pretreatment unit and transformed, compressed, adsorbed and removed carbon dioxide in the pretreatment unit before entering the hydrogen production unit. A very small part of the tail gas enters the air compressor for compression and is stored in the gas storage box for heating in the heating furnace. The raw gas in the hydrogen production unit is purified to a hydrogen concentration of 99.99% after pressure swing adsorption again. The first purified hydrogen enters the hydrogenation unit; Step 2: The hydrogenation unit purifies and saturates the light benzene and hydrogen, and the generated BTXS fraction is sent to the pre-distillation unit. After entering the pre-distillation unit, the BTXS fraction is subjected to slight positive pressure distillation to form the BT fraction at the top of the tower and the XS fraction at the bottom of the tower. The XS fraction enters the shell and tube heat exchanger module, and the hydrogen and light benzene raw materials generated subsequently enter the shell and tube heat exchanger module to exchange heat with the XS fraction. Step 3: After the light benzene raw material exchanges heat with the XS fraction in step 2, the light benzene raw material after heat exchange in the shell and tube heat exchanger module is insulated by utilizing the heat absorption and heat preservation effect of the heat preservation module, thereby minimizing the heat loss of the light benzene raw material.

2. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 1, characterized in that: A main switch valve is provided on the right surface of the pretreatment unit, a three-way pipe is provided at one end of the main switch valve, an electric control valve is provided at one end of the three-way pipe, a raw gas delivery pipe is provided at one end of the electric control valve, an air compressor is provided at one end of the raw gas delivery pipe, a gas storage box is installed at one end of the air compressor, a pressure stabilizing valve is installed on the right side of the gas storage box, and a heating furnace is installed at one end of the pressure stabilizing valve; A heat transfer pipe is provided on the back of the heating furnace, a hydrogenation unit is provided at one end of the heat transfer pipe, a suction pump pipe group is provided on the upper surface of the hydrogenation unit, a shell and tube heat exchanger module is installed on the hydrogenation unit through the suction pump pipe group, and an insulation module is installed on the surface of the shell and tube heat exchanger module.

3. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 2, characterized in that: A hydrogen production suction pump pipe group is provided on the upper surface of the shell and tube heat exchanger module, and a hydrogen production unit is installed on the shell and tube heat exchanger module through the hydrogen production suction pump pipe group. A hydrogen production unit valve is provided on the left side of the hydrogen production unit, and a three-way pipe is installed at one end of the hydrogen production unit valve.

4. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 2, characterized in that: The lower surface of the shell and tube heat exchanger module is sequentially installed with an XS fraction inlet pipe and an XS fraction discharge pipe from left to right, the shell and tube heat exchanger module is installed with a tower bottom through the XS fraction inlet pipe, the top of the tower bottom is provided with a pre-distillation unit, the top of the pre-distillation unit is provided with a tower top, the surface of the tower bottom is provided with an XS fraction pipe, the tower bottom is installed with a pre-distillation unit through the XS fraction pipe, the surface of the pre-distillation unit is provided with a BT fraction pipe, and the pre-distillation unit is installed with a tower top through the BT fraction pipe.

5. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 4, characterized in that: A tower top suction pump pipe group is provided on the top of the tower top, an extraction distillation unit is installed on the tower top through the tower top suction pump pipe group, a pre-distillation unit connecting pipe is provided on the left surface of the pre-distillation unit, a hydrogenation unit is installed on the pre-distillation unit through the pre-distillation unit connecting pipe, and a tank body is installed at one end of the XS fraction discharge pipe.

6. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 2, characterized in that: The shell and tube heat exchanger module includes an upper heat exchanger, the upper surface of which is provided with an upper surface left connection end and an upper surface right connection end from left to right, the bottom of the upper heat exchanger is fixedly connected with an upper connecting plate, the bottom of the upper connecting plate is provided with an upper boron nitride ceramic, and the bottom of the upper boron nitride ceramic is provided with a middle graphene heat conductive plate.

7. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 6, characterized in that: The bottom of the middle graphene heat conducting sheet is provided with a bottom boron nitride ceramic, the bottom of the bottom boron nitride ceramic is provided with a bottom connecting sheet, the bottom of the middle graphene heat conducting sheet is provided with a heat conducting rod, the bottom of the bottom connecting sheet is fixedly connected with a bottom left end heat exchanger, and the bottom of the bottom left end heat exchanger is provided with a left support seat and a bottom left connecting end from left to right in sequence.

8. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 7, characterized in that: A left end connecting plate is provided on the right side of the bottom left end heat exchanger, a left circulating water cooler is provided on the right side of the left end connecting plate, a middle connecting plate is provided on the right side of the left circulating water cooler, a middle circulating water cooler is provided on the right side of the middle connecting plate, a right end connecting plate is provided on the right side of the middle circulating water cooler, a right circulating water cooler is provided on the right side of the right end connecting plate, and an XS fraction electric control valve and a right support seat are provided at the bottom of the right circulating water cooler from left to right.

9. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 8, characterized in that: A jack is provided on the right side of the right circulating water cooler, a sealed ring is installed on the inner wall of the jack, a temperature controller is provided on the inner wall of the sealed ring, a data cable is provided on the top of the temperature controller, a PLC temperature controller is installed on the temperature controller through the data cable, baffles are provided inside the left circulating water cooler, the middle circulating water cooler and the right circulating water cooler, and a water inlet and a water outlet are provided on the front of the left circulating water cooler, the middle circulating water cooler and the right circulating water cooler from left to right.

10. The device for recovering waste heat from XS fraction to increase the temperature of light benzene feed according to claim 2, characterized in that: The thermal insulation module includes a light-collecting mirror, a top connecting iron sheet is provided at the bottom of the light-collecting mirror, a bolt base is fixedly connected to the surface of the top connecting iron sheet, a bottom arc-shaped connecting sleeve is provided at the bottom of the bolt base, and the bottom arc-shaped connecting sleeve is threadedly connected to the bolt base through a connecting bolt, a black film layer is provided on the inner wall of the light-collecting mirror, heat-absorbing graphene is provided on the inner wall of the black film layer, a heat transfer rod is provided at the bottom of the heat-absorbing graphene, a thermal insulation layer is provided at the bottom of the thermal insulation layer, a heat-conducting layer is provided at the bottom of the thermal insulation layer, and a threaded fastening ring is threadedly connected to the surface of the connecting bolt.

Images