Resource utilization method of tower bottoms of tower for preparing gamma-butyrolactone product through dehydrogenation of 1, 4-butanediol

Abstract

The invention discloses a resource utilization method of tower bottoms of a tower for preparing a gamma-butyrolactone product through dehydrogenation of 1, 4-butanediol. The method comprises the following steps: a, mixing tower bottoms of a GBL product tower and optional BDO, gasifying, and carrying out dehydrogenation reaction under the hydrogen condition and under the action of a copper-based catalyst; b, after the dehydrogenation reaction, flash evaporation and rectification separation are carried out, a tower top product is sent to a GBL main device for further refining, and a tower kettle heavy component continues to be subjected to a hydrogenation reaction in an optional alcohol solvent; and c, rectifying and separating the hydrogenation product again, feeding the tower top product to a BDO main device for further refining, and selectively recycling the tower kettle heavy component for hydrogenation reaction and / or incineration treatment. According to the method, resource utilization of BDO, GBL, heavy components and the like in the tower bottoms of the tower for preparing GBL products through dehydrogenation of BDO can be fully achieved, and recycling of useful components is achieved to the maximum extent.

Description

Technical Field

[0001] The invention relates to a resource utilization method, in particular to a resource utilization method for a tower bottom liquid produced by dehydrogenating 1,4-butanediol to produce gamma-butyrolactone. Background Art

[0002] With the rapid development of the new energy vehicle industry, the demand for N-methylpyrrolidone, a key solvent in the battery production process, continues to increase. γ-Butyrolactone (GBL) is the raw material for the production of N-methylpyrrolidone, and the dehydrogenation and cyclization of 1,4-butanediol (BDO) is the main method for industrial production of GBL. With the increasingly fierce competition, the market price of GBL continues to fall, and the economic benefits of production enterprises have been severely compressed, which has put forward higher and higher requirements for cost reduction and efficiency improvement in the production process.

[0003] In the process of dehydrogenating BDO to produce GBL, byproducts such as tetrahydrofuran, n-butanol, and 2-(4-hydroxybutoxy)tetrahydrofuran (TBA) are obtained. The crude GBL is first separated into light components such as tetrahydrofuran and n-butanol in a light removal tower, and then unreacted BDO, 2-(4-hydroxybutoxy)tetrahydrofuran (TBA), etc. are separated in a product tower to finally obtain pure GBL. Among them, the heavy components in the bottom liquid of the product tower are difficult to reuse, and are generally incinerated in the industry, but they still contain more than 50% BDO and a small amount of high-value-added chemicals such as GBL. If they can be used as resources, it is expected to further reduce the production cost of GBL and improve the market competitiveness of the device.

[0004] The main reason why the tower bottom liquid of GBL products is difficult to recycle is that it contains a large amount of TBA, and TBA and BDO are azeotropic, and it is impossible to separate the two at a low cost through distillation. In addition, the residual TBA in BDO will affect the color of the BDO product and interfere with the polymerization reaction, resulting in a decrease in product quality. Some small companies retain the tower bottom liquid of the product until the end of the catalyst operation for dehydrogenation treatment, but with the scale of GBL production and the large-scale GBL equipment, this method is no longer feasible.

[0005] Regarding the refining of BDO, some methods for removing TBA have been proposed in related literature. For example, patent CN117645586A uses an acidic catalyst to dehydrate the azeotrope at the top of the BDO product tower to produce tetrahydrofuran, thereby reducing the difficulty of separating acetal species such as TBA in subsequent units. Although its raw material claims to use BDO crude products with a high acetal mass content (0.1-5%), the reaction will produce additional dibutylene glycol as a by-product, and the condensed species are all treated as waste, and the overall utilization rate is poor. For example, patent CN115716778A uses a low-temperature purification and crystallization method to purify BDO, but the economic efficiency is not good enough, it has not been successfully industrialized, and there are certain requirements for the purity of BDO crude products.

[0006] Therefore, it is necessary to propose a new solution for resource utilization of GBL product tower bottom liquid. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a resource utilization method of the bottom liquid of a tower produced by dehydrogenating 1,4-butanediol to produce γ-butyrolactone.

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

[0009] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, comprising the process flow of the following method 1 or method 2;

[0010] Method 1:

[0011] a. The GBL product tower bottom liquid and the optional BDO are mixed and then gasified, and dehydrogenation reaction is carried out under hydrogen conditions and the action of a copper-based catalyst;

[0012] b. After the dehydrogenation reaction, the product is flashed and distilled to separate. The top product is sent to the GBL main unit for further refining, and the heavy components in the bottom of the tower are further hydrogenated in an optional alcohol solvent;

[0013] c. The obtained hydrogenation product is distilled and separated again, and the top product is sent to the BDO main unit for further refining, and the heavy components in the bottom of the tower are selectively recycled to the hydrogenation reaction and / or incineration treatment;

[0014] In the above method 1, the bottom liquid of the GBL product tower is first subjected to a dehydrogenation reaction to convert the BDO therein into GBL, and then the hydrogen is separated by flash evaporation, and then the top product whose main component is GBL is separated by distillation, which can be directly sent to the GBL main unit for further refining, so as to recover GBL; the remaining heavy components are further subjected to a hydrogenation reaction to obtain small molecular products (such as TBA hydrogenation to obtain BDO and tetrahydrofuran, butyl butyrate hydrogenation to obtain butanol, etc.), and after distillation separation, the light components including BDO can be directly sent to the BDO main unit for further refining to recover BDO, thereby realizing the resource utilization of the bottom liquid of the GBL product tower, and each recycled component has no adverse effect on the GBL main unit and the BDO main unit, thereby avoiding the accumulation of heavy components to increase the refining difficulty of the product or affect the product quality.

[0015] Method 2:

[0016] d. The bottom liquid of the GBL product tower is subjected to hydrogenation reaction in an optional alcohol solvent;

[0017] e. The obtained hydrogenation product and the optional BDO are mixed and then gasified, and a dehydrogenation reaction is carried out under hydrogen conditions and the action of a copper-based catalyst;

[0018] f. After the dehydrogenation reaction, the product is flashed and distilled to separate. The top product is sent to the GBL main unit for further refining, and the heavy components in the bottom of the tower are selectively recycled to the hydrogenation reaction and / or incineration treatment;

[0019] The above method 2 is another feasible route. First, the GBL product tower bottom liquid is subjected to hydrogenation reaction to convert heavy components such as TBA and butyl butyrate into hydrogenation products such as BDO, tetrahydrofuran, and n-butanol; the obtained hydrogenation product is further subjected to dehydrogenation reaction to further convert the BDO from the tower bottom liquid and the BDO generated from the hydrogenation reaction into GBL, and then the hydrogen is separated by flash evaporation, and then the top product with GBL as the main component is separated by distillation, which can be directly sent to the GBL main device for further refining, so as to realize the resource utilization of the GBL product tower bottom liquid. This method can further improve the recovery rate of GBL, and has no adverse effects on the GBL main device, avoiding the accumulation of heavy components to increase the difficulty of product refining or affect product quality.

[0020] In addition, the top product obtained by distillation separation of the dehydrogenation product in the present invention is mainly GBL, and also contains a small amount of light components such as tetrahydrofuran, n-butanol, and 2-hydroxytetrahydrofuran, which can be sent to the GBL main device for further refining, so the separation capacity of the distillation equipment is not strictly required. The present invention has no special restrictions on the structure of the distillation equipment, which can be a plate tower, a packed tower, etc., but avoids sieve plate towers that are easily blocked. In order to avoid the problem of further polymerization and coking of heavy components caused by excessive temperature, the distillation equipment is designed as a negative pressure tower in most application examples, and its vacuum degree is not particularly limited.

[0021] In the present invention, the GBL product tower bottoms liquid comprises 50-80wt% of BDO, 1-30wt% of GBL, 0.5-10wt% of TBA, and 1-20wt% of other components.

[0022] As some preferred examples of the present invention, in process flow a, BDO is used to dilute the bottom liquid of the GBL product tower, wherein the mixing mass ratio of BDO to the bottom liquid of the GBL product tower is 0-10, preferably 2-8;

[0023] Preferably, in process flow e, BDO is used to dilute the hydrogenation product, wherein the mixing mass ratio of BDO to the hydrogenation product is 0-10, preferably 0-5.

[0024] The present invention has no special requirements on the source and purity of the BDO raw material for dilution. It can be a crude BDO product with a purity of 99.0% or more, a qualified BDO product with a purity of 99.5% or more, or a superior BDO product with a purity of 99.7% or more, obtained by purification by the acetylene aldehyde method, maleic anhydride method, propylene method, or fermentation method. It can also be a BDO recovery liquid with a purity of 98.0% or more obtained by further purification of the acetylene aldehyde method distillation residue, or a mixed raw material of BDO, butanol, GBL, and tetrahydrofuran after removing heavy components with a boiling point higher than BDO by maleic anhydride method. In particular, the BDO recovery liquid obtained by purifying the acetylene aldehyde method distillation residue is still not high enough in purity and is difficult to sell as a product, which is very suitable for the application scenario of the present invention.

[0025] As some preferred examples of the present invention, the copper-based catalyst used in the dehydrogenation reaction has a total pore volume of ≥0.3 mL / g and a specific surface area of ​​≥50 m 2 / g of supported catalyst, preferably the copper content in the copper-based catalyst is 5-40%, preferably 10-30%;

[0026] Although the common composition of the catalyst used for dehydrogenation of BDO to produce GBL is familiar to those in the industry, the dehydrogenation catalyst used in the present invention needs to have unique structural characteristics: (1) The total pore volume of the catalyst is required to be ≥ 0.3 mL / g, for example, it can be 0.3 mL / g, 0.6 mL / g, 0.9 mL / g, 1.2 mL / g, 1.5 mL / g, etc. If the total pore volume of the catalyst is less than 0.3 mL / g, the unvaporized heavy components in the reaction raw materials are easily covered on the catalyst surface and rapidly deactivated. (2) The catalyst is required to have a rich surface structure, with a specific surface area of ​​≥ 50 m 2 / g, for example, 50m 2 / g、100m 2 / g, 250m 2 / g、500m 2 / g、1000m 2 / g, etc. If the catalyst surface area is less than 50m 2 / g, the dehydrogenation reaction is difficult, and the copper particles are easily sintered due to insufficient dispersion during the high-temperature reaction and reactivation process.

[0027] The dehydrogenation catalyst in the present invention can be selected from commercially available products, or synthesized by referring to the methods disclosed in known literature or patents, such as the dehydrogenation catalyst preparation methods disclosed in patents CN117654528A and CN117582993A. In addition, pores can be formed during the catalyst preparation process using known soft template methods, hard template methods, self-assembly methods, etc., so as to obtain a dehydrogenation catalyst with increased total pore volume and specific surface area, so that it can maintain a high catalyst activity for a long time in the application scenario of the present invention.

[0028] Among them, the organic templates selected by the soft template method include polyethylene glycol, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, carboxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, polyvinyl pyrrolidone, stearate, field sesbania powder, walnut shell powder, polyolefin powder, polyacrylamide, polyacrylic acid microspheres, polystyrene microspheres, coal tar, etc. The hard template method is to remove aluminum oxide, silicon oxide, metal element particles, etc. by inorganic acid, inorganic base, high temperature, etc. to produce mesoporous and macroporous structures. The self-assembly method uses organic small molecule templates such as organic amines and organic ammonium salts in combination with macromolecules and even polymer materials to prepare carriers and catalysts with rich pore structures. In some application examples, the catalyst has both mesoporous and macroporous structures, and the active component copper is more dispersed at this time.

[0029] Preferably, the copper-based catalyst contains any one or more of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanide metals, titanium, zirconium, hafnium, chromium, molybdenum, tungsten, manganese, zinc, gallium, indium, oxygen, and carbon as an auxiliary agent.

[0030] Preferably, the carrier in the copper-based catalyst is one or more of silicon oxide, silicon carbide, carbon, carbon nitride, aluminum nitride, aluminum carbide, aluminum oxide, and zinc oxide.

[0031] As some preferred examples of the present invention, the dehydrogenation reaction is carried out in a tubular fixed bed reactor, the reaction needs to ensure that BDO is in a gasified state, and the difference between the lowest temperature and the highest temperature in the reaction tube is ≤30°C, such as 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, etc.; this is because when the difference between the cold spot and the hot spot of the reactor is too large, the bed temperature will be partially uneven, and the excessive reaction of BDO at the hot spot may increase the content of low-boiling by-products such as tetrahydrofuran and n-butanol, and the insufficient reaction of BDO at the cold spot may increase the content of high-boiling by-products such as TBA. Effective methods for reducing the temperature difference between the cold spot and the hot spot in the reactor include reducing the diameter of the reaction tube, reducing the length of the reaction tube, increasing the disturbance degree of the heat supply fluid such as heat transfer oil liquid or steam, adjusting the overall flow direction of the feed gas and the heat supply fluid, and other strategies known in the industry. Typical reaction tube diameters may be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, etc., and typical reaction tube lengths may be 1 m, 2 m, 3 m, 4 m, 5 m, 7 m, 10 m, etc. A typical method for increasing the degree of disturbance of the heating fluid is to set more baffles and spoilers in the reactor. The overall co-flow of the feed gas and the heating fluid can make the heating fluid in the reactor part where the reaction is most concentrated and the heat supply is most needed be in the highest temperature and most heat energy range. The heating fluid is preferably thermal oil vapor.

[0032] Preferably, the reaction temperature of the dehydrogenation reaction is 200-280°C; and / or, the reaction pressure is 0.05-0.50 MPaG; and / or, the raw material mass space velocity is 0.01-1.00 h -1 ; The dehydrogenation reaction is carried out under hydrogen conditions.

[0033] Some high-boiling-point heavy components in the feedstock are difficult to fully gasify in the reactor. During long-term operation, they are enriched, polymerized, and coked on the surface of the dehydrogenation catalyst, resulting in decreased catalyst activity and even blockage of the fluid pipeline. Therefore, the catalyst needs to be reactivated when the BDO content in the dehydrogenation product is too high.

[0034] As some preferred examples of the present invention, when the BDO content in the dehydrogenation product obtained by the dehydrogenation reaction is too high, the copper-based catalyst is reactivated, and the specific method is: the raw material is switched to pure BDO and the catalyst activity is significantly restored. In other application examples, the reduction treatment is carried out at 200-300°C with hydrogen after stopping the feed; depending on the different tolerance of the catalyst to the reduction temperature, the optional reactivation temperature can be 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, etc., and there is no special requirement for the reduction and reactivation time. Among them, when the BDO content in the dehydrogenation product obtained by the dehydrogenation reaction is 1wt% or more, preferably 2.5wt% or more, the copper-based catalyst is reactivated. More commonly, the reactivation treatment is carried out when the BDO content in the dehydrogenation product is higher than 1wt% to avoid irreversible loss of catalyst activity.

[0035] As some preferred examples of the present invention, in process flow b, alcohol solvents are used to dilute the heavy components in the bottom of the tower after the dehydrogenation product is distilled and separated, wherein the mixing mass ratio of the alcohol solvent to the heavy components in the bottom of the tower is 0-10, preferably 2-8; the alcohol solvent dilutes the heavy components on the one hand, and on the other hand, it is also an efficient hydrogen dissolving agent, which is conducive to the smooth progress of the gas-liquid-solid three-phase reaction and reduces the pressure and temperature required for the hydrogenation reaction. In some embodiments, a small amount of water (<2%) is also introduced to enhance the decomposition of heavy components such as acetals and esters.

[0036] Preferably, in process flow d, an alcohol solvent is used to dilute the GBL product tower bottom liquid, wherein the mixing mass ratio of the alcohol solvent to the GBL product tower bottom liquid is 0-10, preferably 2-8;

[0037] Preferably, the alcohol solvent is selected from one or more of methanol, ethanol, propanol, butanol and 1,4-butanediol.

[0038] As some preferred examples of the present invention, the hydrogenation reaction is carried out in a tubular fixed bed reactor or a kettle reactor; when the amount of alcohol solvent added is small (such as less than 40% by mass), a kettle reactor is preferred and stirring measures are used to enhance the mass transfer process, and a powder structure hydrogenation catalyst is selected. In some application examples, two or more catalysts are required for hydrogenation in series, and a tubular fixed bed reactor is preferred, and a shaped hydrogenation catalyst is selected for segmented loading.

[0039] Preferably, the hydrogenation reaction is carried out in the presence of a hydrogenation catalyst comprising at least one of the metals of Groups VI and VIII; the hydrogenation catalyst is preferably a catalyst comprising at least one of the following metals: iron, cobalt, nickel, palladium, platinum, ruthenium, rhodium, iridium, chromium, molybdenum, tungsten, more preferably at least one of iron, cobalt, nickel, palladium, platinum, ruthenium, rhodium, iridium supported on conventional carrier materials such as aluminum oxide, silicon oxide, titanium oxide, zinc oxide, molecular sieve, carbon material or a monolithic catalyst, or at least one of chromium, molybdenum, tungsten, cobalt, nickel sulfide, carbide, nitride supported on conventional carrier materials such as aluminum oxide, silicon oxide, titanium oxide, zinc oxide, molecular sieve, carbon material or a monolithic catalyst, and other industrially known hydrogenation catalysts, which are not particularly limited.

[0040] Preferably, the reaction temperature of the hydrogenation reaction is 50-250°C, for example, 50°C, 100°C, 150°C, 200°C, 250°C, etc.; and / or, the reaction pressure is 1-20MPaG, for example, 1MPaG, 4MPaG, 8MPaG, 12MPaG, 16MPaG, 20MPaG, etc.; and / or, the feed mass space velocity is 0.01-1.00 -1 ;;The dehydrogenation reaction is carried out under hydrogen conditions.

[0041] Compared with the prior art, the present invention has the following positive effects:

[0042] 1. The process route is novel, which can fully realize the resource utilization of BDO, GBL, heavy components, etc. in the bottom liquid of the BDO dehydrogenation to GBL product tower, maximize the recovery of useful components, and the products can be refined using the original separation and purification equipment of the GBL main production unit and the BDO main production unit, further reducing the cost of resource utilization and GBL production cost.

[0043] 2. The present invention adopts a total pore volume ≥ 0.3mL / g and a specific surface area ≥ 50m 2 / g copper-based dehydrogenation catalyst has the advantages of high dispersion of active copper species, high temperature resistance, sintering resistance, and carbon deposition resistance. It is suitable for the dehydrogenation reaction of BDO in tower bottom liquid of GBL product with high heavy component content. It can operate stably for a long time and save operating costs.

[0044] 3. In a specific usage scenario, the present invention uses hydrogen and / or pure BDO raw materials to reactivate the dehydrogenation catalyst that shows a trend of deactivation, which can effectively remove the high-boiling-point heavy components remaining on the surface of the dehydrogenation catalyst to prevent them from covering the active sites and causing the catalyst activity to decrease or slow down the trend of the catalyst activity decrease.

[0045] 4. The dehydrogenation reaction and the hydrogenation reaction are used in series, and the operation is flexible, the process is simple, the conditions are stable, and the interference with the operation of the GBL and BDO main units is small. It is particularly suitable for the continuous recovery of all components of the tower bottom liquid of the by-product GBL product of the 100,000-ton GBL unit, and has potential industrial promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic diagram of the process flow of the scheme in Example 1;

[0047] Among them, 1-raw material tank, 2-dehydrogenation feed pump, 3-atomizer, 4-gasifier, 5-dehydrogenation reactor, 6-cooler, 7-flash tower, 8-deweighting tower, 9-heavy component tank, 10-hydrogenation feed pump, 11-hydrogenation reactor.

[0048] Figure 2 This is a schematic diagram of the process flow of the scheme in Example 4;

[0049] Among them, 12-hydrogenation raw material tank, 13-hydrogenation feed pump, 14-hydrogenation reactor, 15-dehydrogenation raw material tank, 16-dehydrogenation feed pump, 17-atomizer, 18-gasifier, 19-dehydrogenation reactor, 20-cooler, 21-flash tower, 22-deweighting tower, 23-heavy component tank. DETAILED DESCRIPTION

[0050] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0051] The product tower bottom liquid in the following examples of the present invention is all from the GBL production device of Wanhua Chemical. Other raw materials and reagents can be purchased through commercial channels unless otherwise specified.

[0052] [Preparation Example 1] Preparation of dehydrogenation catalyst

[0053] Dehydrogenation catalyst A: Prepare the catalyst 10% Cu-10% Zn-5% Ca-2% Cr / carrier according to the method in Example 1 of patent CN117654528A. The total pore volume of the catalyst is 0.72 mL / g, and the specific surface area is 210 m 2 / g.

[0054] Dehydrogenation catalyst B: Prepare the catalyst 30% CuO-8% In2O3-6% MoO3-1% Li2O-55% SiO2 according to the method in Example 4 of patent CN117582993A. The total pore volume of the catalyst is 0.35 mL / g, and the specific surface area is 62 m 2 / g.

[0055] Dehydrogenation catalyst C: The catalyst 30% CuO-8% In2O3-6% MoO3-1% Li2O-55% SiO2 was prepared mainly according to the method in Example 4 of patent CN117582993A, but different from dehydrogenation catalyst B, 1% polyvinyl pyrrolidone (K30) was added to the solution system before the ammonia evaporation operation. The total pore volume of the catalyst was 0.55 mL / g, and the specific surface area was 109 m 2 / g.

[0056] [Preparation Example 2] Preparation of hydrogenation catalyst

[0057] Hydrogenation catalyst M: Prepare Pd-Ta / SiO2 catalyst according to the method in Example 2 of patent CN118287139A.

[0058] Hydrogenation catalyst N: Al-Ni catalyst was prepared according to the method in Example 1 of patent CN114011433B.

[0059] Hydrogenation catalyst Q: Ru-Pd / MgAlO prepared according to the method in Example 4 of patent CN110433823B x catalyst.

[0060] [Example 1]

[0061] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, the process flow of which is as follows: Figure 1 shown):

[0062] (1) The GBL product tower bottom liquid (composition: 50wt% BDO, 28.9% GBL, 9.8wt% TBA, 11.3wt% other components) and BDO are mixed in a mass ratio of 1:2 and enter the raw material tank 1, and are pumped to the atomizer 3 by the dehydrogenation feed pump 2 and enter the gasifier 4 after being fully mixed with hydrogen; the obtained gasified raw material enters the dehydrogenation reactor 5 (tubular fixed bed) filled with dehydrogenation catalyst A, and the reaction temperature is 250°C, the reaction pressure is 0.10MPaG, and the mass space velocity is 0.20h -1The dehydrogenation reaction is carried out under the conditions of , and the obtained dehydrogenation product is cooled by the cooler 6 and enters the flash tower 7. The gas phase product at the top of the tower is mainly hydrogen, which can be recycled, and the liquid phase dehydrogenation product (composition: 0.6wt% BDO, 94.0wt% GBL, 2.1wt% TBA, 3.3wt% other components) is obtained at the bottom of the tower.

[0063] (2) The liquid dehydrogenation product is sent to a de-weighting tower 8 for distillation separation. The top product (GBL content ≥ 95%) is sent to the GBL main unit for further refining. The heavy component in the bottom of the tower is buffered by the heavy component tank 9 and then sent to the hydrogenation reactor 11 filled with a hydrogenation catalyst M through a hydrogenation feed pump 10, where it is mixed with hydrogen and a BDO solvent with a mass of 3 times that of the heavy component and reacted at a reaction temperature of 120° C., a reaction pressure of 5 MPaG, and a mass space velocity of 1.00 h -1 The hydrogenation reaction was carried out under the conditions of to obtain a hydrogenated product (TBA content 1.2%).

[0064] (3) The resulting hydrogenation product is distilled and separated again, and the top product is sent to the BDO main unit for further refining, and the heavy components in the bottom of the tower are incinerated.

[0065] After 920 hours of stable operation using the scheme in this embodiment, the BDO content in the dehydrogenation product increases to 5%. The raw material in step (1) can be switched to pure BDO for operation, and the reaction conditions remain unchanged. After 100 hours of operation, the raw material is switched back and the operation is continued according to the original scheme to restore the catalytic activity.

[0066] [Example 2]

[0067] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, the process flow of which is as follows: Figure 1 shown):

[0068] (1) The GBL product tower bottom liquid (composition: 75.2wt% BDO, 10.3wt% GBL, 5.2wt% TBA, 9.3wt% other components) and BDO are mixed in a mass ratio of 1:5 and enter the raw material tank 1, and are pumped to the atomizer 3 by the dehydrogenation feed pump 2 and enter the gasifier 4 after being fully mixed with hydrogen; the obtained gasified raw material enters the dehydrogenation reactor 5 (tubular fixed bed) filled with the dehydrogenation catalyst B, and the reaction temperature is 200°C, the reaction pressure is 0.50MPaG, and the mass space velocity is 0.10h -1 The dehydrogenation reaction is carried out under the conditions of , and the obtained dehydrogenation product is cooled by the cooler 6 and enters the flash tower 7. The gaseous product at the top of the tower is mainly hydrogen, which can be recycled, and the liquid dehydrogenation product (composition: 0.3wt% BDO, 96.8wt% GBL, 1.2t% TBA, 1.7wt% other components) is obtained at the bottom of the tower.

[0069] (2) The liquid dehydrogenation product is sent to a deweighting tower 8 for distillation separation. The top product (GBL content ≥ 95%) is sent to the GBL main unit for further refining. The heavy component in the bottom of the tower is buffered by the heavy component tank 9 and then sent to the hydrogenation reactor 11 filled with hydrogenation catalyst N through the hydrogenation feed pump 10. The reaction temperature is 50°C, the reaction pressure is 20 MPaG, and the mass space velocity is 0.20 h -1 The hydrogenation reaction was carried out under the conditions of to obtain a hydrogenated product (TBA content 0.2%).

[0070] (3) The resulting hydrogenation product is distilled and separated again, and the top product is sent to the BDO main unit for further refining, and the heavy components in the bottom of the tower are incinerated.

[0071] After 6600 hours of stable operation using the scheme in this embodiment, the BDO content in the dehydrogenation product increases to more than 1%. The raw material in step (1) can be switched to pure BDO for operation without changing the reaction conditions. After 100 hours of operation, the raw material can be switched back and the operation can be continued according to the original scheme to restore the catalytic activity.

[0072] [Example 3]

[0073] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, the process flow is as follows: Figure 1 shown):

[0074] (1) The GBL product tower bottom liquid (composition: 80wt% BDO, 1.2wt% GBL, 2.2wt% TBA, 16.6wt% other components) enters the raw material tank 1, is pumped to the atomizer 3 by the dehydrogenation feed pump 2, and enters the gasifier 4 after being fully mixed with hydrogen; the obtained gasified raw material enters the dehydrogenation reactor 5 (tubular fixed bed) filled with the dehydrogenation catalyst C, and the reaction temperature is 280°C, the reaction pressure is 0.05MPaG, and the mass space velocity is 1.00h -1 The dehydrogenation reaction is carried out under the conditions of , and the obtained dehydrogenation product is cooled by the cooler 6 and enters the flash tower 7. The gas phase product at the top of the tower is mainly hydrogen, which can be recycled, and the liquid phase dehydrogenation product (composition: 0.8wt% BDO, 80.1wt% GBL, 2.4wt% TBA, 16.7wt% other components) is obtained at the bottom of the tower.

[0075] (2) The liquid dehydrogenation product is sent to a de-weighting tower 8 for distillation separation. The top product (GBL content ≥ 95%) is sent to the GBL main unit for further refining. The heavy component in the bottom of the tower is buffered by the heavy component tank 9 and then sent to the hydrogenation reactor 11 filled with a hydrogenation catalyst Q through a hydrogenation feed pump 10, where it is mixed with hydrogen and a BDO solvent with a mass of 1 times that of the heavy component, and the reaction temperature is 250°C, the reaction pressure is 15 MPaG, and the mass space velocity is 0.05 h -1The hydrogenation reaction was carried out under the conditions of to obtain a hydrogenated product (TBA content 1.0%).

[0076] (3) The resulting hydrogenation product is distilled and separated again, and the top product is sent to the BDO main unit for further refining, and the heavy components in the bottom of the tower are incinerated.

[0077] After 500 hours of stable operation using the scheme in this embodiment, the BDO content in the dehydrogenation product increases to more than 2.5%. The raw material in step (1) can be switched to pure BDO for operation, and the reaction conditions remain unchanged. After 100 hours of operation, the feed is stopped and the reaction is reduced with hydrogen at 260° C. for 24 hours, and then the operation is continued according to the original scheme to restore the catalytic activity.

[0078] [Example 4]

[0079] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, the process flow is as follows: Figure 2 shown):

[0080] (1) The bottom liquid of the GBL product tower (composition: 75.2wt% BDO, 10.3wt% GBL, 5.2wt% TBA, 9.3wt% other components) was first fed into the hydrogenation feed tank 12, and then pumped to the hydrogenation reactor 14 (tank reactor) by the hydrogenation feed pump 13. At the same time, 0.5wt% of the mass of the bottom liquid of the tower and 3 times the mass of the heavy component of the BDO solvent were added, and hydrogen was introduced. The hydrogenation reaction was carried out under the conditions of a reaction temperature of 150°C and a reaction pressure of 20MPa. After 24h of reaction, the sample was taken for analysis, and the TBA content in the hydrogenation product was 0.8%.

[0081] (2) The obtained hydrogenation product and BDO are mixed in a dehydrogenation feed tank 15 at a mass ratio of 1:2, and are pumped to an atomizer 17 through a dehydrogenation feed pump 16 and then enter a gasifier 18 after being fully mixed with hydrogen; the obtained gasified feed enters a dehydrogenation reactor 5 (tubular fixed bed) filled with a dehydrogenation catalyst B, and the reaction temperature is 260°C, the reaction pressure is 0.1 MPaG, and the mass space velocity is 1.00 h -1 The dehydrogenation reaction is carried out under the conditions of , and the obtained dehydrogenation product is cooled by the cooler 20 and enters the flash tower 21. The gas phase product at the top of the tower is mainly hydrogen, which can be recycled, and the liquid phase dehydrogenation product (composition: 0.3wt% BDO, 98.7wt% GBL, 0.3wt% TBA, 0.7wt% other components) is obtained at the bottom of the tower.

[0082] (3) The liquid dehydrogenation product is sent to the deweighting tower 22 for distillation separation, and the top product (GBL content 99.5%) is sent to the GBL main unit for further refining. The heavy components in the bottom of the tower are buffered in the heavy component tank 23, 60% of which is recycled to the hydrogenation reaction and 40% is incinerated.

[0083] In the scheme of this embodiment, after step (2) was continuously operated for 8000 h, the BDO content in the dehydrogenation product did not increase significantly, and the catalyst stability was good.

[0084] [Example 5]

[0085] A method for resource utilization of tower bottom liquid from 1,4-butanediol dehydrogenation to produce γ-butyrolactone product, the process flow of which is as follows: Figure 2 shown):

[0086] (1) The GBL product tower bottom liquid (composition: 80 wt% BDO, 1.2 wt% GBL, 2.2 wt% TBA, 16.6 wt% other components) is first fed into the hydrogenation feed tank 12, and then pumped into the hydrogenation reactor 11 filled with hydrogenation catalyst N via the hydrogenation feed pump 13, and the reaction temperature is 50°C, the reaction pressure is 10 MPaG, and the mass space velocity is 0.20 h -1 The hydrogenation reaction was carried out under the conditions of to obtain a hydrogenated product (TBA content 0.5%).

[0087] (2) The obtained hydrogenation product enters the dehydrogenation feed tank 15, is pumped to the atomizer 17 through the dehydrogenation feed pump 16, and enters the gasifier 18 after being fully mixed with hydrogen; the obtained gasified raw material enters the dehydrogenation reactor 5 (tubular fixed bed) filled with dehydrogenation catalyst B, and the reaction temperature is 230°C, the reaction pressure is 0.30 MPaG, and the mass space velocity is 0.25 h -1 The dehydrogenation reaction is carried out under the conditions of , and the obtained dehydrogenation product is cooled by the cooler 20 and enters the flash tower 21. The gas phase product at the top of the tower is mainly hydrogen, which can be recycled, and the liquid phase dehydrogenation product (composition: 0.4wt% BDO, 93.3wt% GBL, 0.6wt% TBA, 5.8wt% other components) is obtained at the bottom of the tower.

[0088] (3) The liquid dehydrogenation product is sent to a deweighting tower 22 for distillation separation, and the top product (GBL content 98.0%) is sent to the GBL main unit for further refining. The heavy components in the bottom of the tower are buffered in the heavy component tank 23, 30% of which is recycled to the hydrogenation reaction and 70% is incinerated.

[0089] In the scheme of this embodiment, after step (2) is continuously operated for 1000 hours, the BDO content in the dehydrogenation product does not increase significantly, and the catalyst stability is good.

[0090] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for resource utilization of the bottom liquid of a tower produced by dehydrogenating 1,4-butanediol to produce γ-butyrolactone, characterized in that: Including the process flow of the following method 1 or method 2; Method 1: a. The GBL product tower bottom liquid and the optional BDO are mixed and then gasified, and dehydrogenation reaction is carried out under hydrogen conditions and the action of a copper-based catalyst; b. After the dehydrogenation reaction, the product is flashed and distilled to separate. The top product is sent to the GBL main unit for further refining, and the heavy components in the bottom of the tower are further hydrogenated in an optional alcohol solvent; c. The obtained hydrogenation product is distilled and separated again, and the top product is sent to the BDO main unit for further refining, and the heavy components in the bottom of the tower are selectively recycled to the hydrogenation reaction and / or incineration treatment; Method 2: d. The bottom liquid of the GBL product tower is subjected to hydrogenation reaction in an optional alcohol solvent; e. The obtained hydrogenation product and the optional BDO are mixed and then gasified, and a dehydrogenation reaction is carried out under hydrogen conditions and the action of a copper-based catalyst; f. After the dehydrogenation reaction, the product is flashed and distilled to separate. The top product is sent to the GBL main unit for further refining, and the heavy components in the bottom of the tower are selectively recycled to the hydrogenation reaction and / or incineration treatment; The GBL product tower bottom liquid comprises 50-80 wt% of BDO, 1-30 wt% of GBL, 0.5-10 wt% of TBA, and 1-20 wt% of other components.

2. The method for resource utilization of the bottom liquid of the tower produced by dehydrogenation of 1,4-butanediol to produce γ-butyrolactone according to claim 1, characterized in that: In process a, BDO is used to dilute the GBL product tower bottom liquid, wherein the mixing mass ratio of BDO to the GBL product tower bottom liquid is 0-10, preferably 2-8; Preferably, in process flow e, BDO is used to dilute the hydrogenation product, wherein the mixing mass ratio of BDO to the hydrogenation product is 0-10, preferably 0-5.

3. The method for resource utilization of the bottom liquid of the tower produced by dehydrogenation of 1,4-butanediol to produce γ-butyrolactone according to claim 1, characterized in that: The copper-based catalyst used in the dehydrogenation reaction has a total pore volume of ≥0.3 mL / g and a specific surface area of ​​≥50 m 2 / g of supported catalyst, preferably the copper content in the copper-based catalyst is 5-40%, preferably 10-30%; Preferably, the copper-based catalyst contains any one or more of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanide metals, titanium, zirconium, hafnium, chromium, molybdenum, tungsten, manganese, zinc, gallium, indium, oxygen, and carbon as an auxiliary agent.

4. The method for resource utilization of the bottom liquid of the tower of 1,4-butanediol dehydrogenation to produce γ-butyrolactone according to any one of claims 1 to 3, characterized in that: The dehydrogenation reaction is carried out in a tubular fixed bed reactor, and the difference between the lowest temperature and the highest temperature in the reaction tube is ≤30°C; Preferably, the reaction temperature of the dehydrogenation reaction is 200-280°C; and / or, the reaction pressure is 0.05-0.50 MPaG; and / or, the raw material mass space velocity is 0.01-1.00 h -1 ; The dehydrogenation reaction is carried out under hydrogen conditions.

5. The method for resource utilization of the bottom liquid of the tower of 1,4-butanediol dehydrogenation to produce γ-butyrolactone according to any one of claims 1 to 4, characterized in that: When the BDO content in the dehydrogenation product obtained by the dehydrogenation reaction is too high, the copper-based catalyst is reactivated. The specific method is: switching the raw material to pure BDO for operation, or performing a reduction treatment with hydrogen at 200-300° C. on the basis of stopping the feed, wherein the copper-based catalyst is reactivated when the BDO content in the dehydrogenation product obtained by the dehydrogenation reaction is 1wt% or more, preferably 2.5wt% or more.

6. The method for resource utilization of the bottom liquid of the tower of 1,4-butanediol dehydrogenation to produce γ-butyrolactone according to any one of claims 1 to 5, characterized in that: In process flow b, the alcohol solvent is used to dilute the heavy components in the bottom of the tower after the dehydrogenation product is distilled and separated, wherein the mixing mass ratio of the alcohol solvent to the heavy components in the bottom of the tower is 0-10, preferably 2-8; Preferably, in process flow d, an alcohol solvent is used to dilute the GBL product tower bottom liquid, wherein the mixing mass ratio of the alcohol solvent to the GBL product tower bottom liquid is 0-10, preferably 2-8; Preferably, the alcohol solvent is selected from one or more of methanol, ethanol, propanol, butanol and 1,4-butanediol.

7. The method for resource utilization of the bottom liquid of the tower of 1,4-butanediol dehydrogenation to produce γ-butyrolactone according to any one of claims 1 to 6, characterized in that: The hydrogenation reaction is carried out in a tubular fixed bed reactor or a tank reactor; Preferably, the hydrogenation reaction is carried out in the presence of a hydrogenation catalyst comprising at least one metal of Group VI and Group VIII metals; the hydrogenation catalyst is preferably a catalyst comprising at least one of the following metals: iron, cobalt, nickel, palladium, platinum, ruthenium, rhodium, iridium, chromium, molybdenum, tungsten; Preferably, the reaction temperature of the hydrogenation reaction is 50-250°C; and / or, the reaction pressure is 1-20 MPaG; and / or, the raw material mass space velocity is 0.01-1.00 h -1 ; The hydrogenation reaction is carried out under hydrogen conditions.

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