Method and device for preparing gamma-butyrolactone from 1, 4-butanediol

Abstract

The invention provides a method and device for preparing gamma-butyrolactone from 1, 4-butanediol, and the method comprises the following steps: carrying out first compression treatment on gamma-butyrolactone obtained by rectification treatment to obtain compressed gamma-butyrolactone; and taking the compressed gamma-butyrolactone as a first heat medium, and carrying out first heat exchange treatment on the reboiling system subjected to rectification treatment and / or the reboiling system subjected to light component removal treatment to obtain first cooled gamma-butyrolactone. According to the method, deep recovery of heat in the system is achieved, the problem that waste heat in the industry is wasted is solved, and low energy consumption and low cost of production are achieved.

Description

Technical Field

[0001] The invention relates to a method for preparing gamma-butyrolactone, in particular to a method and device for preparing gamma-butyrolactone from 1,4-butanediol, and belongs to the technical field of organic chemistry. Background Art

[0002] GBL (gamma-butyrolactone) is a widely used organic intermediate. As a high boiling point solvent and proton-type strong solvent, it can be used as a battery electrolyte, and can also be used to prepare N-methylpyrrolidone, butyric acid, amber paint remover, etc. It is widely used in the synthesis of fine chemicals such as medicine and fragrance. The production routes of GBL include 1,4-butanediol dehydrogenation method, succinic anhydride hydrogenation and dehydrogenation process, and most of the domestic methods use 1,4-butanediol gas phase dehydrogenation method.

[0003] The gas phase dehydrogenation method of 1,4-butanediol is to carry out the dehydrogenation reaction at a temperature of 230-240°C and a hydrogen atmosphere. The crude GBL is continuously distilled in a light-removal tower and a GBL product distillation tower to obtain pure GBL. The light-removal tower removes light-boiling products, mainly including water (H2O) and tetrahydrofuran (THF), and the light-boiling products are removed and enter the distillation tower to obtain the GBL product. The above process flow and equipment greatly improve the production efficiency of GBL, but the reaction and distillation consume very high energy, and with the increase in the demand for GBL applications, the contradiction of high energy consumption has become increasingly prominent.

[0004] Therefore, how to reduce the production energy consumption of the 1,4-butanediol gas phase dehydrogenation method and save production and operation costs is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The invention provides a method for preparing gamma-butyrolactone from 1,4-butanediol. The method realizes deep recovery of heat in the system, solves the problem of waste heat in the industry, and realizes low energy consumption and low cost in production.

[0006] The present invention also provides a device for preparing γ-butyrolactone from 1,4-butanediol, which can recover waste heat, improve energy utilization efficiency, further reduce energy consumption in the production process, and has low operating costs.

[0007] The present invention provides a method for preparing γ-butyrolactone from 1,4-butanediol, comprising the following steps:

[0008] performing a first compression treatment on the γ-butyrolactone obtained through the rectification treatment to obtain compressed γ-butyrolactone;

[0009] The compressed γ-butyrolactone is used as a first heat medium to perform a first heat exchange treatment on the reboiling system of the distillation treatment and / or the reboiling system of the light removal treatment to obtain a first cooled γ-butyrolactone.

[0010] The method as described above, wherein further comprises:

[0011] Using the first cooled γ-butyrolactone as a second heat medium to perform a second heat exchange treatment on the crude product to be de-lightened, to obtain the preheated crude product to be de-lightened and the second cooled γ-butyrolactone;

[0012] Performing the light removal treatment on the preheated crude product to be light-removed to obtain a light-removed crude product;

[0013] The light-removed crude product is subjected to the distillation treatment.

[0014] The method as described above, wherein further comprises:

[0015] The second cooled γ-butyrolactone is used as a first preheating medium to perform a first preheating treatment on 1,4-butanediol to obtain preheated 1,4-butanediol and a third cooled γ-butyrolactone.

[0016] The method as described above, wherein further comprises:

[0017] The preheated 1,4-butanediol is subjected to a second preheating treatment, a hydrogen mixing treatment, a third preheating treatment, and a vaporization treatment, and then subjected to a dehydrogenation reaction to obtain a crude product including γ-butyrolactone;

[0018] The crude product is used as a second preheating medium to sequentially participate in the third preheating treatment and the second preheating treatment to obtain a residual heat crude product;

[0019] The waste heat crude product is subjected to heat recovery treatment and gas-liquid separation treatment in sequence to obtain hydrogen and the crude product to be lightly removed.

[0020] The method as described above, wherein further comprises:

[0021] performing a second compression process on the hydrogen to obtain compressed hydrogen;

[0022] The compressed hydrogen is subjected to a heating treatment, and the heated hydrogen is used as a vaporizing medium and mixed with the preheated 1,4-butanediol to perform the hydrogen mixing treatment;

[0023] Wherein, after participating in the third preheating treatment, the second preheating medium sequentially participates in the temperature raising treatment and the second pretreatment.

[0024] The present invention also provides a device for preparing γ-butyrolactone from 1,4-butanediol, comprising a lightness removal tower, a distillation tower and a first compressor;

[0025] The high boiling outlet of the light-removal tower is communicated with the distillation inlet of the distillation tower, the γ-butyrolactone outlet of the distillation tower is communicated with the compression inlet of the first compressor, and the compression outlet of the first compressor is communicated with the medium inlet of the distillation tower reboiler of the distillation tower and / or the medium inlet of the light-removal tower reboiler of the light-removal tower.

[0026] The device as described above, wherein, further comprises a heat exchanger before light-removal, wherein the heat medium inlet of the heat exchanger before light-removal is connected to the medium inlet of the distillation tower reboiler and / or the medium inlet of the light-removal tower reboiler; and the outlet of the crude product to be removed from the heat exchanger before light-removal is connected to the light-removal inlet of the light-removal tower.

[0027] The device as described above, wherein it further comprises a first raw material preheater, and the heat medium outlet of the pre-light stripping heat exchanger is connected to the heat medium inlet of the first raw material preheater.

[0028] The device as described above, wherein it further comprises a second raw material preheater, a third raw material preheater, a mixer, a vaporizer, a dehydrogenation reactor, a waste heat recovery device and a gas-liquid separator;

[0029] The raw material outlet of the first raw material preheater is communicated with the raw material inlet of the second raw material preheater, the raw material outlet of the second raw material preheater is communicated with the raw material inlet of the mixer, the raw material outlet of the mixer is communicated with the raw material inlet of the third raw material preheater, the raw material outlet of the third raw material preheater is communicated with the vaporization inlet of the vaporizer, and the vaporization outlet of the vaporizer is communicated with the reaction inlet of the dehydrogenation reactor;

[0030] The reaction outlet of the dehydrogenation reactor is connected to the heat medium inlet of the third raw material preheater, and the heat medium outlet of the third raw material preheater is connected to the heat medium inlet of the second raw material preheater;

[0031] The heat medium outlet of the second raw material preheater is connected to the heat medium inlet of the waste heat recovery device, the heat medium outlet of the waste heat recovery device is connected to the separation inlet of the gas-liquid separator, and the liquid phase outlet of the gas-liquid separator is connected to the inlet of the crude product to be removed from the heat exchanger before light removal.

[0032] The device as described above, wherein it further comprises a second compressor and a gas temperature riser, and the heat medium outlet of the third raw material preheater is connected to the heat medium inlet of the second raw material preheater through the gas temperature riser;

[0033] The gas phase outlet of the gas-liquid separator is communicated with the inlet of the second compressor, the outlet of the second compressor is communicated with the gas inlet of the gas warmer, and the gas outlet of the gas warmer is communicated with the gas inlet of the mixer.

[0034] The method for preparing gamma-butyrolactone from 1,4-butanediol of the present invention uses the gamma-butyrolactone obtained by distillation as a high-temperature heat source to provide heat for light removal and distillation treatment, which not only ensures the normal operation of light removal and distillation treatment, but also deeply recovers the heat generated in the system, saves steam consumption, and reduces production costs.

[0035] The device for preparing γ-butyrolactone from 1,4-butanediol of the present invention fully recovers the latent heat and sensible heat of the process gas by matching and integrating the heat source and heat sink in the device. The heat at the reactor outlet is further recovered by step coupling, the consumption of heat transfer oil is reduced, and the purpose of efficient heat recovery and energy consumption reduction is achieved. At the same time, the vaporization time of the material in the vaporizer is reduced, and the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of a device for preparing γ-butyrolactone from 1,4-butanediol according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of a device for preparing γ-butyrolactone from 1,4-butanediol in a comparative example of the present invention.

[0038] Description of reference numerals:

[0039] 1. Light-removal tower; 2. Distillation tower; 3. First compressor; 4. Heat exchanger before light-removal; 5. Crude product reflux tank; 6. First raw material preheater; 7. Raw material storage tank; 8. Second raw material preheater; 9. Third raw material preheater; 10. Mixer; 11. Dehydrogenation reactor; 12. Condenser; 13. Gas-liquid separator; 14. Waste heat recovery device; 15. First buffer tank; 16. Superheater; 17. Second compressor; 18. Gas temperature riser; 19. Gas buffer tank; 20. Vaporizer; 1a. Light-removal tower reboiler; 2a. Distillation tower reboiler; 2b. Steam reboiler. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The first aspect of the present invention provides a method for preparing γ-butyrolactone from 1,4-butanediol, comprising the following steps: performing a first compression treatment on the γ-butyrolactone obtained by distillation treatment to obtain compressed γ-butyrolactone; using the compressed γ-butyrolactone as a first heat medium, performing a first heat exchange treatment on a reboiling system of the distillation treatment and / or a reboiling system of light removal treatment to obtain a first cooled γ-butyrolactone.

[0042] Generally, 1,4-butanediol undergoes a dehydrogenation reaction at high temperature to obtain a crude product including γ-butyrolactone, hydrogen, tetrahydrofuran, water and high-boiling impurities. The crude product is subjected to a light removal treatment and a distillation treatment in sequence to finally obtain a pure γ-butyrolactone. As a specific embodiment, the light removal treatment is carried out in a light removal tower, and the distillation treatment is carried out in a distillation tower.

[0043] Specifically, during the operation of the distillation treatment and the light removal treatment, part of the contents in the tower will flow out of the tower as a reboiling system, and then enter the tower after being heated outside the tower, thereby providing heat for the normal operation of the distillation treatment and the light removal treatment. In the distillation treatment of the present invention, after γ-butyrolactone flows out from the top of the distillation tower as a low-boiling substance, due to its high temperature, it is first subjected to a first compression treatment before being collected to obtain compressed γ-butyrolactone with increased temperature and pressure. The compressed γ-butyrolactone is then used as the first heat medium to provide heat for at least one of the distillation treatment and the light removal treatment, that is, the high-temperature γ-butyrolactone is used to heat the reboiling system of the distillation treatment and the light removal treatment, so that the gas phase latent heat of the high-temperature γ-butyrolactone is used as a heat source to replace the heat source steam used for reboiling in the distillation treatment and the light removal treatment. In the specific implementation process, the high-temperature γ-butyrolactone can preferentially meet the heat supply of the light removal treatment reboiling system.

[0044] Since γ-butyrolactone is derived from distillation, the present invention recovers waste heat from the heat generated in the system during the production process, reduces the steam demand for light removal and distillation, and greatly reduces production energy consumption and production costs. In addition, it is used as the first heat medium to provide heat for the distillation and light removal processes in the process of preparing γ-butyrolactone from 1,4-butanediol, which have relatively large heat demands. The heat energy level matching is also more reasonable, which significantly improves the heat utilization rate.

[0045] The present invention does not limit the specific parameters of the first compression treatment. In a specific embodiment, the temperature of the compressed γ-butyrolactone is 150-180°C, and the pressure is controlled at 13-35 kPa. After the first heat exchange treatment, the temperature of the first cooled γ-butyrolactone is 165-140°C.

[0046] In addition, in order to ensure the efficiency of light removal and distillation treatment, the bottom temperature of the light removal tower is 135-140°C, and the bottom temperature of the distillation tower is 130-152°C.

[0047] After the first heat exchange treatment is completed, the temperature of the first heat medium is reduced to become the first cooled γ-butyrolactone. In order to further improve the heat utilization rate, in addition to refluxing part of the first cooled γ-butyrolactone to participate in the distillation treatment, the remaining first cooled γ-butyrolactone can also be reused as a heat medium in the production system.

[0048] Based on the temperature requirement of the light removal treatment, in a specific embodiment, the first cooled γ-butyrolactone can also be used as a second heat medium to perform a second heat exchange treatment on the crude product to be de-lightened. In detail, before the crude product to be de-lightened is subjected to the light removal treatment, the first cooled γ-butyrolactone is used to perform a second heat exchange treatment on it, so that the crude product to be de-lightened is heated by the heat of the first cooled γ-butyrolactone to obtain a preheated crude product to be de-lightened. When the preheated crude product to be de-lightened is subjected to the light removal treatment to generate the light-removed crude product, not only the heat demand during the light removal treatment is reduced, but also the demand for external preheating medium for the crude product to be de-lightened is reduced, and energy consumption is further reduced. Subsequently, the light-removed crude product is subjected to the aforementioned distillation treatment to obtain γ-butyrolactone.

[0049] During the above-mentioned second heat exchange treatment, the heat in the first cooled γ-butyrolactone is absorbed by the crude product to be de-lightened and then cooled to the second cooled γ-butyrolactone. Furthermore, the second cooled γ-butyrolactone can be used as the first preheating medium to perform the first preheating treatment on 1,4-butanediol to obtain preheated 1,4-butanediol and the third cooled γ-butyrolactone. Among them, 1,4-butanediol is the raw material for preparing γ-butyrolactone, and after γ-butyrolactone successively undergoes the above-mentioned first heat exchange treatment, the second heat exchange treatment and the first preheating treatment, the heat is deeply recovered and collected in the final state of the third cooled γ-butyrolactone for downstream applications. Generally, after the above-mentioned heat recovery, the temperature of the third cooled γ-butyrolactone is 50-60°C.

[0050] In the above preparation method, the heat of γ-butyrolactone obtained by distillation treatment undergoes at least three heat exchange treatments, which respectively provide heat for distillation treatment, light-removal treatment, preheating treatment before light-removal treatment, and raw material preparation treatment, thereby realizing gradient recovery and application of heat, greatly improving the utilization efficiency of waste heat in the system, reducing energy consumption, and saving costs.

[0051] Further, after the first preheating treatment, the raw material 1,4-butanediol can be preheated before the dehydrogenation reaction in order to further reach the reaction temperature of the dehydrogenation reaction, and can be subjected to multiple preheating treatments and vaporization treatments. For example, the preheated 1,4-butanediol can be subjected to a second preheating treatment, a hydrogen mixing treatment, a third preheating treatment, and a vaporization treatment to gradually increase the temperature of the 1,4-butanediol before the dehydrogenation reaction, reduce the amount of heat transfer oil used in the dehydrogenation reaction, and the hydrogen mixing treatment and the vaporization treatment can ensure that the 1,4-butanediol participates in the dehydrogenation reaction in a dispersed vaporized state, thereby improving the dehydrogenation reaction efficiency. It should be noted that the present invention does not strictly limit the order of the second preheating treatment, the hydrogen mixing treatment, the vaporization treatment, and the third preheating treatment, as long as the temperature of the 1,4-butanediol is gradually increased.

[0052] In a specific embodiment, the second preheating treatment, hydrogen mixing treatment, third preheating treatment and vaporization treatment can be carried out in sequence. After the vaporization treatment is completed, 1,4-butanediol is subjected to a dehydrogenation reaction to obtain a crude product including γ-butyrolactone. It should be added that, as needed, after the vaporization treatment, 1,4-butanediol can be subjected to an overheating treatment and then subjected to a dehydrogenation reaction. At this time, even if heat transfer oil is required for overheating treatment, the amount of heat transfer oil used will be significantly reduced due to the pretreatment of 1,4-butanediol by the second preheating treatment, hydrogen mixing treatment, third preheating treatment and vaporization treatment.

[0053] Generally, the temperature of the crude product is 230-240°C. Therefore, in order to further recover the heat in the system, the crude product can be used as the second preheating medium to participate in the third preheating treatment and the second preheating treatment in sequence to obtain a waste heat crude product; the waste heat crude product is sequentially subjected to heat recovery treatment and gas-liquid separation treatment to obtain hydrogen and a crude product to be de-lightened.

[0054] In the above process, the heat of the crude product obtained by the dehydrogenation reaction is used to perform the third preheating treatment and the second preheating treatment on the raw material 1,4-butanediol, respectively, so as to realize the recovery of the residual heat of the crude product and obtain the residual heat crude product. Since the residual heat crude product still has a certain amount of heat, the residual heat can be recovered, for example, the heat can be recovered with low-temperature water to produce hot water.

[0055] As mentioned above, in the dehydrogenation reaction, in addition to the target product γ-butyrolactone, by-products such as water, hydrogen, and THF are also generated. Therefore, in order to improve the purity of γ-butyrolactone, the crude product after heat recovery treatment can be subjected to gas-liquid separation treatment. In the gas-liquid separation treatment, the low-boiling gas phase in the crude product will be separated from the high-boiling liquid phase to obtain hydrogen and a crude product to be de-lightened. It should be noted that the hydrogen referred to in the present invention refers to a mixture with a hydrogen volume percentage of not less than 90%, which may also be mixed with some unseparated droplets and other low-boiling substances. After the gas-liquid separation treatment, the crude product to be de-lightened including γ-butyrolactone will participate in the second heat exchange treatment and then undergo a de-lightening treatment.

[0056] In addition, in order to further improve the efficiency of gas-liquid separation, a condensation process can be added between the heat recovery process and the gas-liquid separation process. The present invention does not limit the type of low-temperature medium for the condensation process, and generally the temperature of the crude product to be delighted including γ-butyrolactone is 35-40°C.

[0057] Furthermore, the hydrogen obtained by the above separation can be used as a vaporizing medium to vaporize the raw material 1,4-butanediol.

[0058] In detail, the hydrogen is subjected to a second compression treatment to obtain compressed hydrogen; the compressed hydrogen is subjected to a temperature increase treatment, and the heated hydrogen is used as a vaporizing medium and mixed with preheated 1,4-butanediol to perform a hydrogen mixing treatment; wherein the second preheating medium, after participating in the third preheating treatment, sequentially participates in the temperature increase treatment and the second pretreatment.

[0059] After the second compression treatment, the hydrogen is compressed with increased temperature and pressure. The compressed hydrogen is then heated using the crude product after the third preheating treatment to obtain a vaporizing medium. The vaporizing medium is mixed with the raw material 1,4-butanediol after the second preheating treatment, thereby helping to increase the vaporization degree of the raw material 1,4-butanediol in the vaporization treatment and improving the efficiency of the dehydrogenation reaction.

[0060] It should be noted that in this process, the crude product generated by the dehydrogenation reaction is sequentially subjected to the third preheating treatment, the temperature increase treatment and the second preheating treatment. That is, the crude product firstly performs the third preheating treatment on the raw material 1,4-butanediol after the vaporization treatment, then performs the heat exchange treatment on the hydrogen, and finally performs the second preheating treatment on the raw material 1,4-butanediol (i.e., the 1,4-butanediol after the first preheating treatment).

[0061] The present invention not only efficiently recycles the heat of γ-butyrolactone obtained by distillation, but also efficiently utilizes the heat of the crude product obtained by the dehydrogenation reaction in stages. By preheating the raw materials in stages and heating the compressed hydrogen, efficient utilization of heat is achieved, reducing the time required for heating the raw materials during vaporization, improving the mixed vaporization effect, and greatly improving production efficiency. At the same time, the amount of heat transfer oil used to provide heat for the dehydrogenation reaction is reduced, and energy consumption is lower.

[0062] like Figure 1 As shown, the second aspect of the present invention also provides a device for preparing γ-butyrolactone from 1,4-butanediol, comprising a light removal tower 1, a distillation tower 2 and a first compressor 3;

[0063] The high boiling outlet of the light removal tower 1 is connected to the distillation inlet of the distillation tower 2, the γ-butyrolactone outlet of the distillation tower 2 is connected to the compression inlet of the first compressor 3, and the compression outlet of the first compressor 3 is connected to the medium inlet of the distillation tower reboiler 2a of the distillation tower 2 and / or the medium inlet of the light removal tower reboiler 1a of the light removal tower 1.

[0064] In detail, the light-removal tower 1 is used for removing light components from a crude product including γ-butyrolactone. The light-removal tower 1 includes a light component outlet and a high boiling point outlet. The light component outlet is used for outputting light components removed from the crude product, and the high boiling point outlet is used for outputting the light-removed crude product; the distillation tower 2 is used for separating the light-removed crude product, the distillation inlet of the distillation tower 2 is used for receiving the light-removed crude product, and the γ-butyrolactone outlet is used for outputting the separated γ-butyrolactone; the first compressor 3 is used for compressing γ-butyrolactone to increase its temperature and pressure.

[0065] Wherein, the light-removing tower 1 and the distillation tower 2 also include respective reboilers. When the γ-butyrolactone outlet at the top of the distillation tower 2 outputs gaseous γ-butyrolactone, the γ-butyrolactone enters the first compressor 3 to be compressed, and then enters the light-removing tower reboiler 1a and / or the distillation tower reboiler 2a for the first heat exchange treatment, providing heat for the light-removing tower 1 and / or the distillation tower 2 to ensure normal operation. The present invention uses the heat from the top of the distillation tower 2 to produce a high-temperature heat source, which is used as the reboiler heat source of the light-removing tower 1 and the distillation tower 2, saving steam consumption. At the same time, through the matching and integration of the heat source and heat sink in the device, the latent heat and sensible heat of the process gas are fully recovered.

[0066] It should be added that when utilizing the heat of γ-butyrolactone, the heat supply of the lightness removal tower 1 can be guaranteed first.

[0067] In addition, a steam reboiler 2b can be provided at the distillation tower 2 in case the heat demand of the light-removal tower 1 for γ-butyrolactone is too high, and the steam reboiler 2b and the distillation tower reboiler 2a (receiving γ-butyrolactone input by the compressor) can jointly provide heat for the distillation tower 2.

[0068] Furthermore, the device of the present invention also includes a heat exchanger 4 before light removal, and the heat medium inlet of the heat exchanger 4 before light removal is connected to the medium inlet of the distillation tower reboiler 2a and / or the medium inlet of the light removal tower reboiler 1a; the outlet of the crude product to be removed from the heat exchanger 4 before light removal is connected to the light removal inlet of the light removal tower 1.

[0069] The pre-light removal heat exchanger 4 is used to perform a second heat exchange treatment on the crude product entering the light removal tower 1. The heat medium inlet of the pre-light removal heat exchanger 4 is connected to at least one of the medium outlet of the distillation tower reboiler 2a and the medium inlet of the light removal tower reboiler 1a, so as to utilize the waste heat of γ-butyrolactone to perform a second heat exchange treatment on the crude product, further improving the heat utilization rate and saving energy consumption. After the crude product completes the second heat exchange treatment, it is output through the crude product outlet to be light-removed of the pre-light removal heat exchanger 4 and enters the light removal tower through the light removal inlet of the light removal tower 1.

[0070] It should be added that the device of the present invention may further include a crude product reflux tank 5, the inlet of which is connected to the medium outlet of at least one of the distillation tower reboiler 2a and the light removal tower reboiler 1a, and the outlet of the crude product reflux tank 5 is connected to the hot medium inlet of the light removal front heat exchanger 4. In addition, the crude product reflux tank 5 also includes another outlet, which is connected to the reflux port of the distillation tower 2, for refluxing part of the γ-butyrolactone into the distillation tower 2.

[0071] Furthermore, the device of the present invention further comprises a first raw material preheater 6 , and the heat medium outlet of the pre-light-removal heat exchanger 4 is connected to the heat medium inlet of the first raw material preheater 6 .

[0072] After γ-butyrolactone has completed the second heat exchange treatment, it still has some residual heat. In order to further avoid the waste of this part of the residual heat, the heat medium outlet of the pre-light heat exchanger 4 is connected with the heat medium inlet of the first raw material preheater 6, so that γ-butyrolactone is used as the first preheating medium and enters the first raw material preheater 6 through the heat medium inlet of the first raw material preheater 6, so as to perform the first preheating treatment on the raw material 1,4-butanediol in the first raw material preheater 6. In a specific embodiment, the raw material 1,4-butanediol comes from the raw material storage tank 7.

[0073] The device of the present invention allows the heat of γ-butyrolactone at the top of the distillation tower 2 to undergo at least three heat exchange treatments, thereby providing heat for distillation treatment, light-removal treatment, preheating treatment before light-removal, and raw material preparation treatment, thereby realizing gradient recovery and application of heat, greatly improving the utilization efficiency of waste heat in the system, reducing energy consumption, and saving costs.

[0074] In addition, the device of the present invention further comprises a second raw material preheater 8, a third raw material preheater 9, a mixer 10, a vaporizer 20, a dehydrogenation reactor 11, a waste heat recovery device 14 and a gas-liquid separator 13; the raw material outlet of the first raw material preheater 6 is connected to the raw material inlet of the second raw material preheater 8, the raw material outlet of the second raw material preheater 8 is connected to the raw material inlet of the mixer 10, the raw material outlet of the mixer 10 is connected to the raw material inlet of the third raw material preheater 9, the raw material outlet of the third raw material preheater 9 is connected to the vaporization inlet of the vaporizer 20, and the vaporizer 20 is connected to the vaporizer 20. The vaporization outlet of the vaporizer 20 is connected to the reaction inlet of the dehydrogenation reactor 11; the reaction outlet of the dehydrogenation reactor 11 is connected to the heat medium inlet of the third raw material preheater 9, and the heat medium outlet of the third raw material preheater 9 is connected to the heat medium inlet of the second raw material preheater 8; the heat medium outlet of the second raw material preheater 8 is connected to the heat medium inlet of the waste heat recovery device 14, and the heat medium outlet of the waste heat recovery device 14 is connected to the separation inlet of the gas-liquid separator 13, and the liquid phase outlet of the gas-liquid separator 13 is connected to the inlet of the crude product to be de-lightened of the pre-lightening heat exchanger 4.

[0075] The second raw material preheater 8 and the third raw material preheater 9 are used to preheat the raw material 1,4-butanediol respectively, the mixer 10 is used to mix the hot hydrogen with the raw material 1,4-butanediol, the vaporizer 20 is used to vaporize the raw material 1,4-butanediol, the dehydrogenation reactor 11 is used to dehydrogenate the preheated vaporized raw material 1,4-butanediol to generate a crude product including γ-butyrolactone, the waste heat recovery device 14 is used to recover the waste heat in the crude product, and the gas-liquid separator 13 is used to perform gas-liquid separation on the crude product to separate the low-boiling gas phase (mainly hydrogen) and the high-boiling liquid phase (mainly γ-butyrolactone) in the crude product. The waste heat recovery device 14 can be a heat pump system.

[0076] It can be understood that in the above-mentioned device, the raw material 1,4-butanediol in the first raw material preheater 6 is output through the raw material outlet of the first raw material preheater 6, and then enters the second raw material preheater 8, the mixer 10, the third raw material preheater 9 and the vaporizer 20 in sequence to obtain the raw material 1,4-butanediol that has been preheated and vaporized in three stages, and then enters the dehydrogenation reactor 11 through the reaction inlet of the dehydrogenation reactor 11 to undergo a dehydrogenation reaction to obtain a crude product including γ-butyrolactone.

[0077] After the crude product carries heat and is output through the reaction outlet of the dehydrogenation reactor 11, it enters the third raw material preheater 9 and the second raw material preheater 8 in sequence to provide preheating medium for the third raw material preheater 9 and the second raw material preheater 8. Therefore, the device of the present invention efficiently utilizes the product heat in the dehydrogenation reactor 11, and supplies it to the second raw material preheater 8 and the third raw material preheater 9 for coupled recovery according to different temperature levels, thereby improving the utilization rate of heat and reducing energy consumption.

[0078] After being output through the heat medium outlet of the second raw material preheater 8, the crude product enters the waste heat recovery device 14 and the gas-liquid separator 13 in sequence to obtain a low-boiling gas phase and a high-boiling liquid phase. The high-boiling liquid phase is the crude product to be de-lightened. After being output through the gas-liquid separator 13, it enters the pre-lightening heat exchanger for the second heat exchange treatment. Among them, the waste heat recovery device 14 is used to re-recover the waste heat in the crude product output through the heat medium outlet of the second raw material preheater 8. For example, the waste heat recovery device 14 can be a heat pump system for producing hot water. In addition, a first buffer tank 15 can also be set between the gas-liquid separator 13 and the pre-lightening heat exchanger 4.

[0079] Furthermore, a superheater 16 may be provided between the vaporizer 20 and the dehydrogenation reactor 11, so as to superheat the vapor outputted from the vaporizer 20 when necessary. For example, the superheater 16 may use heat transfer oil to superheat the vapor.

[0080] Furthermore, a condenser 12 may be added between the waste heat recovery device 14 and the gas-liquid separator 13 to perform condensation processing, thereby improving the separation efficiency of the gas-liquid separator 13 .

[0081] The device of the present invention recovers the outlet heat of the dehydrogenation reactor 11 through step coupling, reduces the consumption of heat transfer oil by the dehydrogenation reactor 11, and achieves the purpose of efficient heat recovery and energy consumption reduction.

[0082] In a specific device, the present invention does not limit the number of dehydrogenation reactors 11, which may be one or multiple reactors connected in parallel. Figure 1 The device comprises two dehydrogenation reactors 11 arranged in parallel.

[0083] Furthermore, the device of the present invention also includes a second compressor 17 and a gas heater 18. The heat medium outlet of the third raw material preheater 9 is connected to the heat medium inlet of the second raw material preheater 8 through the gas heater 18; the gas phase outlet of the gas-liquid separator 13 is connected to the inlet of the second compressor 17, the outlet of the second compressor 17 is connected to the gas inlet of the gas heater 18, and the gas outlet of the gas heater 18 is connected to the gas inlet of the mixer 10.

[0084] In detail, the low-boiling gas phase outputted from the gas phase outlet of the gas-liquid separator 13 enters the second compressor 17 to be compressed, and then enters the gas warmer 18. The heat medium of the gas warmer 18 comes from the third raw material preheater 9. Specifically, after the raw material is preheated in the third raw material preheater 9, the crude product first enters the gas warmer 18 to heat the low-boiling gas phase, and then enters the second raw material preheater 8 to preheat the raw material from the first raw material preheater 6. The heated low-boiling gas phase enters the mixer 10 as a vaporizing medium and is mixed with the raw material from the second raw material preheater 8, thereby helping to improve the vaporization efficiency in the vaporizer 20, reduce the vaporization time of the vaporizer 20, and improve production efficiency.

[0085] In addition, a gas buffer tank 19 may be provided between the gas-liquid separator 13 , the second compressor 17 , and the gas temperature increaser 18 .

[0086] Example

[0087] This embodiment adopts Figure 1 The device (10wt / a) shown in the figure uses 1,4-butanediol as a raw material to prepare γ-butyrolactone. The device includes: a raw material storage tank 7, a first raw material preheater 6, a second raw material preheater 8, a mixer 10, a third raw material preheater 9, a vaporizer 20, a superheater 16, a dehydrogenation reactor 11, a gas warmer 18, a gas buffer tank 19, a condenser 12, a gas-liquid separator 13, a second compressor 17, a waste heat recovery device 14, a first buffer tank 15, a heat exchanger before light removal 4, a light removal tower 1, a light removal tower reboiler 1a, a distillation tower 2, a distillation tower reboiler 2a, a steam reboiler 2b, a first compressor 3, and a crude product reflux tank 5.

[0088] The outlet of the raw material storage tank 7 is communicated with the raw material inlet of the first raw material preheater 6, the raw material outlet of the first raw material preheater 6 is communicated with the raw material inlet of the second raw material preheater 8, the raw material outlet of the second raw material preheater 8 is communicated with the raw material inlet of the mixer 10, the outlet of the mixer 10 is communicated with the raw material inlet of the third raw material preheater 9, the raw material outlet of the third raw material preheater 9 is connected to the vaporization inlet of the vaporizer 20, the vaporization outlet of the vaporizer 20 is communicated with the inlet of the superheater 16, the outlet of the superheater 16 is communicated with the reaction inlet of the dehydrogenation reactor 11, the reaction outlet of the dehydrogenation reactor 11 and the third raw material preheater are connected. The heat medium inlet of the raw material preheater 9 is connected, the heat medium outlet of the third raw material preheater 9 is connected to the heat medium inlet of the gas temperature riser 18, the heat medium outlet of the gas temperature riser 18 is connected to the heat medium inlet of the second raw material preheater 8, the heat medium outlet of the second raw material preheater 8 is connected to the heat medium inlet of the waste heat recovery device 14, the heat medium outlet of the waste heat recovery device 14 is connected to the condensation inlet of the condenser 12, the condensation outlet of the condenser 12 is connected to the separation inlet of the gas-liquid separator 13, and the liquid phase outlet of the gas-liquid separator 13 is connected to the inlet of the crude product to be removed of the pre-light removal heat exchanger 4 through the first buffer tank 15.

[0089] The gas phase outlet of the gas-liquid separator 13 is connected to the inlet of the second compressor 17 through the gas buffer tank 19 , the outlet of the second compressor 17 is connected to the gas inlet of the gas heater 18 , and the gas outlet of the gas heater 18 is connected to the gas inlet of the mixer 10 .

[0090] The outlet of the crude product to be delighted of the heat exchanger 4 before delighting is connected to the delighting inlet of the delighting tower 1, the high boiling outlet of the delighting tower 1 is connected to the distillation inlet of the distillation tower 2, the γ-butyrolactone outlet of the distillation tower 2 is connected to the compression inlet of the first compressor 3, and the compression outlet of the first compressor 3 is respectively connected to the medium inlet of the distillation tower reboiler 2a of the distillation tower 2 and the medium inlet of the delighting tower reboiler 1a of the delighting tower 1.

[0091] The medium inlet of the distillation tower reboiler 2a and the medium inlet of the light removal tower reboiler 1a are respectively connected to the inlet of the crude product reflux tank 5, one outlet of the crude product reflux tank 5 is connected to the heat medium inlet of the heat exchanger 4 before light removal, and the other outlet of the crude product reflux tank 5 is connected to the reflux port of the distillation tower 2.

[0092] In the operation of the device of this embodiment, according to the method of the present invention, the γ-butyrolactone output from the γ-butyrolactone outlet of the distillation tower 2 is used as the first heat medium, which is compressed by the first compressor 3 and sent to the light removal tower reboiler 1a and the distillation tower reboiler 2a to recover the gas phase latent heat, and then sent to the pre-light removal heat exchanger 4 and the first raw material preheater 6 to recover the liquid phase sensible heat. At the same time, the crude product output from the reaction outlet of the coupled dehydrogenation reactor 11 is sent to the third raw material preheater 9, the gas warmer 18 and the second raw material preheater 8 in turn according to different temperature levels for heat recovery and utilization. The operating conditions are shown in Table 1.

[0093] Comparative Example

[0094] This comparative example adopts Figure 2 The device (10wt / a) shown in the figure uses 1,4-butanediol as a raw material to prepare γ-butyrolactone. The device includes: a raw material storage tank 7, a mixer 10, a vaporizer 20, a superheater 16, a dehydrogenation reactor 11, a gas warmer 18, a condenser 12, a gas-liquid separator 13, a second compressor 17, a first buffer tank 15, a gas buffer tank 19, a light removal tower 1, a light removal tower reboiler 1a, a distillation tower 2, a steam reboiler 2b, and a crude product reflux tank 5.

[0095] The outlet of the raw material storage tank 7 is connected to the raw material inlet of the mixer 10, the outlet of the mixer 10 is connected to the reaction inlet of the dehydrogenation reactor 11 through the vaporizer 20 and the superheater 16, the reaction outlet of the dehydrogenation reactor 11 is connected to the heat medium inlet of the gas heater 18, the heat medium outlet of the gas heater 18 is connected to the condensation inlet of the condenser 12, the condensation outlet of the condenser 12 is connected to the separation inlet of the gas-liquid separator 13, and the liquid phase outlet of the gas-liquid separator 13 is connected to the inlet of the first buffer tank 15.

[0096] The gas phase outlet of the gas-liquid separator 13 is connected to the inlet of the second compressor 17 through the gas buffer tank 19 , the outlet of the second compressor 17 is connected to the gas inlet 5 of the gas warmer 18 , and the gas outlet of the gas warmer 18 is connected to the gas inlet of the mixer 10 .

[0097] The outlet of the first buffer tank 15 is connected to the light removal inlet of the light removal tower 1, the high boiling outlet of the light removal tower 1 is connected to the distillation inlet of the distillation tower 2, the γ-butyrolactone outlet of the distillation tower 2 is connected to the inlet of the crude product reflux tank 5, one outlet of the crude product reflux tank 5 is connected to the reflux port of the distillation tower 2, and the other outlet of the crude product reflux tank 5 outputs γ-butyrolactone.

[0098] The difference from the embodiment is that the crude product stream (240°C) at the reaction outlet of the dehydrogenation reactor 11 enters the gas warmer 18 to preheat the hydrogen, and the remaining heat is cooled by the condenser; the high-temperature heat of the γ-butyrolactone output by the distillation tower 2 enters the circulating water cooler for cooling, the load of the light removal tower 1 is provided by steam to the light removal tower reboiler 1a, and the load of the distillation tower 2 is provided by the steam reboiler 2b. The operating conditions are shown in Table 1.

[0099] Table 1

[0100]

[0101] As can be seen from Table 1, the steam consumption of the embodiment is reduced by 91% compared with the comparative example, the heat transfer oil consumption is reduced by 42%, the circulating water consumption is reduced by 1172t / h, and the new compressor power consumption is 746KW / h. The overall annual operating cost is lower than that of the comparative example, and the energy-saving effect and economic benefits are obvious.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing γ-butyrolactone from 1,4-butanediol, characterized in that: The following steps are involved: performing a first compression treatment on the γ-butyrolactone obtained through the rectification treatment to obtain compressed γ-butyrolactone; The compressed γ-butyrolactone is used as a first heat medium to perform a first heat exchange treatment on the reboiling system of the distillation treatment and / or the reboiling system of the light removal treatment to obtain a first cooled γ-butyrolactone.

2. The method according to claim 1, characterized in that Also includes: Using the first cooled γ-butyrolactone as a second heat medium to perform a second heat exchange treatment on the crude light product to be removed, to obtain a preheated crude light product to be removed and a second cooled γ-butyrolactone; Performing the light removal treatment on the preheated crude product to be light-removed to obtain a light-removed crude product; The light-removed crude product is subjected to the distillation treatment.

3. The method according to claim 2, characterized in that Also includes: The second cooled γ-butyrolactone is used as a first preheating medium to perform a first preheating treatment on 1,4-butanediol to obtain preheated 1,4-butanediol and a third cooled γ-butyrolactone.

4. The method according to claim 3, characterized in that Also includes: The preheated 1,4-butanediol is subjected to a second preheating treatment, a hydrogen mixing treatment, a third preheating treatment, and a vaporization treatment, and then subjected to a dehydrogenation reaction to obtain a crude product including γ-butyrolactone; The crude product is used as a second preheating medium to sequentially participate in the third preheating treatment and the second preheating treatment to obtain a residual heat crude product; The waste heat crude product is subjected to heat recovery treatment and gas-liquid separation treatment in sequence to obtain hydrogen and the crude product to be lightly removed.

5. The method according to claim 4, characterized in that Also includes: performing a second compression process on the hydrogen to obtain compressed hydrogen; The compressed hydrogen is subjected to a heating treatment, and the heated hydrogen is used as a vaporizing medium and mixed with the preheated 1,4-butanediol to perform the hydrogen mixing treatment; Wherein, after participating in the third preheating treatment, the second preheating medium sequentially participates in the temperature raising treatment and the second pretreatment.

6. A device for preparing γ-butyrolactone from 1,4-butanediol, characterized in that: It comprises a lightness removal tower (1), a distillation tower (2) and a first compressor (3); The high boiling outlet of the light-removal tower (1) is communicated with the distillation inlet of the distillation tower (2), the γ-butyrolactone outlet of the distillation tower (2) is communicated with the compression inlet of the first compressor (3), and the compression outlet of the first compressor (3) is communicated with the medium inlet of the distillation tower reboiler (2a) of the distillation tower (2) and / or the medium inlet of the light-removal tower reboiler (1a) of the light-removal tower (1).

7. The device according to claim 6, characterized in that It also comprises a heat exchanger (4) before light-removal, wherein the heat medium inlet of the heat exchanger (4) before light-removal is connected to the medium inlet of the distillation tower reboiler (2a) and / or the medium inlet of the light-removal tower reboiler (1a); and the outlet of the crude product to be removed from the heat exchanger (1a) before light-removal is connected to the light-removal inlet of the light-removal tower (1).

8. The device according to claim 7, characterized in that It also includes a first raw material preheater (6), and the heat medium outlet of the pre-light removal heat exchanger (1a) is connected to the heat medium inlet of the first raw material preheater (6).

9. The device according to claim 8, characterized in that It also includes a second raw material preheater (8), a third raw material preheater (9), a mixer (10), a vaporizer (20), a dehydrogenation reactor (11), a waste heat recovery device (14) and a gas-liquid separator (13); The raw material outlet of the first raw material preheater (6) is connected to the raw material inlet of the second raw material preheater (8), the raw material outlet of the second raw material preheater (8) is connected to the raw material inlet of the mixer (10), the raw material outlet of the mixer (10) is connected to the raw material inlet of the third raw material preheater (9), the raw material outlet of the third raw material preheater (9) is connected to the vaporization inlet of the vaporizer (20), and the vaporization outlet of the vaporizer (20) is connected to the reaction inlet of the dehydrogenation reactor (11); The reaction outlet of the dehydrogenation reactor (11) is connected to the heat medium inlet of the third raw material preheater (9), and the heat medium outlet of the third raw material preheater (9) is connected to the heat medium inlet of the second raw material preheater (8); The heat medium outlet of the second raw material preheater (8) is connected to the heat medium inlet of the waste heat recovery device (14), the heat medium outlet of the waste heat recovery device (14) is connected to the separation inlet of the gas-liquid separator (13), and the liquid phase outlet of the gas-liquid separator (13) is connected to the inlet of the crude product to be removed from the pre-light-removal heat exchanger (4).

10. The device according to claim 9, characterized in that It also includes a second compressor (17) and a gas temperature riser (18), and the heat medium outlet of the third raw material preheater (9) is connected to the heat medium inlet of the second raw material preheater (8) through the gas temperature riser (18); The gas phase outlet of the gas-liquid separator (13) is connected to the inlet of the second compressor (17), the outlet of the second compressor (17) is connected to the gas inlet of the gas warmer (18), and the gas outlet of the gas warmer (18) is connected to the gas inlet of the mixer (10).

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