Preparation system of 1, 4-butanediol and co-production system of 1, 4-butanediol and alkyl-1, 4-butanediol

Abstract

The utility model discloses a preparation system of 1, 4-butanediol and a co-production system of 1, 4-butanediol and alkyl-1, 4-butanediol. The 1, 4-butanediol preparation system uses the two-stage bubbling bed hydrogenation reactor, so that the service cycle of the catalyst can be effectively prolonged. On the basis of the system, the system for co-producing the alkyl-1, 4-butanediol can be obtained by arranging an aldehyde supplementing end and a cocatalyst feeding end, co-production of the 1, 4-butanediol and the alkyl-1, 4-butanediol is achieved, even the proportion of the alkyl-1, 4-butanediol in the product can be regulated and controlled, and the highest proportion can reach 25 wt%.

Description

Technical Field

[0001] This utility model belongs to the field of chemical industry, specifically relating to a system for preparing 1,4-butanediol and a system for the co-production of 1,4-butanediol and alkyl-1,4-butanediol. Background Technology

[0002] 1,4-Butanediol (BDO) is commonly used in the production of tetrahydrofuran (THF), polytetrahydrofuran (PTMEG), γ-butyrolactone (GBL), N-pyrrolidone, etc., and is also commonly used in the synthesis of polyesters such as PBS, PBAT, PBT and other biodegradable materials.

[0003] Alkyl-1,4-butanediol (MBDO), especially 2-methyl-1,4-butanediol, possesses similar properties to BDO, and its downstream modified products are similar to those of BDO. However, due to the presence of methyl groups in its side chains, MBDO also exhibits superior properties compared to BDO. For example, 3-methyltetrahydrofuran synthesized from MBDO can be used as a raw material in the pharmaceutical industry. It can also be polymerized with other monomers to serve as a prepolymer in industries such as synthetic fibers, TPU, and slurries, significantly improving the low-temperature performance and biocompatibility of elastomers. This is all due to the presence of methyl branches in the molecular side chains, which gives the polymers better ductility and low-temperature resistance.

[0004] Currently, MBDO mainly originates as a byproduct of BDO production units, particularly the Rapper process BDO units, which typically produce approximately 0.1–0.3% MBDO, which is usually removed as an impurity. For example, patent document CN 219232322 U discloses a two-stage hydrogenation unit employing a stirred tank with a fixed bed in series. However, this unit is used to suppress MBDO byproducts from BDO production and mentions that conventional two-stage hydrogenation reactors are trickle beds with slow bed flow rates and localized high temperatures that affect catalyst lifetime. In other words, there is no production unit that can directly synthesize MBDO based on existing BDO units, and it is even more difficult to obtain BDO products with adjustable MBDO concentrations. Summary of the Invention

[0005] To improve the above-mentioned technical problems, the present invention provides a 1,4-butanediol preparation system, comprising:

[0006] 1,4-Butynediol synthesis reactor;

[0007] Formaldehyde circulation tower located downstream of the 1,4-butynediol synthesis reactor;

[0008] The first hydrogenation reactor and the second hydrogenation reactor are located downstream of the formaldehyde circulation tower. The first hydrogenation reactor and the second hydrogenation reactor are connected in series. The first hydrogenation reactor and the second hydrogenation reactor are bubble bed hydrogenation reactors, and both are equipped with nickel-based catalyst layers inside.

[0009] And a distillation unit located downstream of the hydrogenation reactor.

[0010] According to the embodiments of this utility model, the 1,4-butynediol synthesis reactor is provided with a feed inlet (e.g., a formaldehyde feed inlet, an acetylene feed inlet) and a discharge outlet, or is further provided with a formaldehyde circulation inlet.

[0011] The formaldehyde circulation tower is equipped with an inlet and an outlet;

[0012] The outlet of the 1,4-butynediol synthesis reactor is connected to the inlet of the formaldehyde circulation tower, and the outlet of the formaldehyde circulation tower is connected to the inlet of the 1,4-butynediol synthesis reactor or the formaldehyde circulation inlet.

[0013] According to an embodiment of this utility model, the 1,4-butynediol synthesis reactor is also provided with a tail gas outlet.

[0014] According to an embodiment of this utility model, the first hydrogenation reactor is provided with an inlet and an outlet, and the outlet of the formaldehyde circulation tower is connected to the inlet of the first hydrogenation reactor.

[0015] According to an embodiment of this utility model, the second hydrogenation reactor is provided with an inlet and an outlet, the outlet of the first hydrogenation reactor is connected to the inlet of the second hydrogenation reactor, and the outlet of the second hydrogenation reactor is connected to the distillation unit.

[0016] According to an embodiment of the present invention, the feed inlet of the first hydrogenation reactor includes a feed inlet for the reaction products of the 1,4-butynediol synthesis reactor and a hydrogen feed inlet.

[0017] According to an embodiment of the present invention, the feed inlet of the second hydrogenation reactor includes a feed inlet for the product of the first hydrogenation reactor and a hydrogen feed inlet.

[0018] According to an embodiment of the present invention, the distillation unit includes: a heavy removal tower, a methanol recovery tower located downstream of the heavy removal tower, and a light removal tower located downstream of the methanol recovery tower.

[0019] According to the embodiments of this utility model, the heavy removal tower, methanol recovery tower and / or light removal tower are plate distillation towers.

[0020] According to the embodiments of this utility model, the heavy phase removal tower, methanol recovery tower and light phase removal tower are all provided with a feed inlet, a gas phase outlet and a liquid phase outlet;

[0021] The outlet of the second hydrogenation reactor is connected to the inlet of the heavy phase removal tower, the gas phase outlet of the heavy phase removal tower is connected to the inlet of the methanol recovery tower, and the liquid phase outlet of the methanol recovery tower is connected to the inlet of the light phase removal tower.

[0022] Furthermore, the heavy components are collected from the liquid phase outlet of the de-heavy tower;

[0023] Methanol is collected from the gas phase outlet of the methanol recovery tower and connected to the methanol oxidation to formaldehyde unit.

[0024] And / or, the liquid phase outlet of the light phase removal tower produces 1,4-butanediol, and the gas phase outlet of the light phase removal tower produces alcohols other than methanol.

[0025] This utility model also provides a system for the co-production of 1,4-butanediol and alkyl-1,4-butanediol, including the above-mentioned 1,4-butanediol preparation system (with or without the above-mentioned formaldehyde circulation tower), wherein the outlet of the 1,4-butynediol synthesis reactor is connected to the inlet of the first hydrogenation reactor.

[0026] Furthermore, the system includes an aldehyde feed end for supplying more aldehyde to the 1,4-butenediol synthesis reactor and / or the first hydrogenation reactor;

[0027] For example, the aldehyde feed end can be located at the feed inlet of the 1,4-butynediol synthesis reactor, and / or at the top, upper, middle and / or bottom of the first hydrogenation reactor.

[0028] According to an embodiment of this invention, the alkyl-1,4-butanediol is an alkyl-substituted 1,4-butanediol, for example, C14-butanediol. 1～20 Alkyl, C 1～10 Alkyl or C 1～4 1,4-Butanediol substituted with alkyl (methyl, ethyl, propyl, isopropyl, butyl, isobutyl) alkyl groups.

[0029] According to an embodiment of this invention, the aldehyde is an aldehyde required to generate the alkyl-1,4-butanediol, for example, C14. 1～20 Aldehydes, C 1～10 Aldehyde or C 1～4 Aldehydes, for example, are formaldehyde, acetaldehyde, propionaldehyde, isopropionaldehyde, butyraldehyde, and isobutyraldehyde.

[0030] That is, when the target product is the co-production of methyl-1,4-butanediol, the aldehyde feed end is used to provide more formaldehyde to the 1,4-butenediol synthesis reactor and / or the first hydrogenation reactor; when the target product is the co-production of ethyl-1,4-butanediol, the aldehyde feed end is used to provide more acetaldehyde to the 1,4-butynediol synthesis reactor and / or the first hydrogenation reactor; and so on.

[0031] According to an embodiment of the present invention, the first hydrogenation reactor and / or the second hydrogenation reactor are further provided with a catalyst feed end.

[0032] According to an embodiment of this utility model, 1,4-butanediol and alkyl-1,4-butanediol are collected from the liquid phase outlet of the light removal tower.

[0033] According to a preferred embodiment of the present invention, the system for the co-production of 1,4-butanediol and alkyl-1,4-butanediol comprises:

[0034] 1,4-Butynediol synthesis reactor;

[0035] Formaldehyde circulation tower located downstream of the 1,4-butynediol synthesis reactor;

[0036] The first hydrogenation reactor and the second hydrogenation reactor are located downstream of the formaldehyde circulation tower. The first hydrogenation reactor and the second hydrogenation reactor are connected in series. The first hydrogenation reactor and the second hydrogenation reactor are bubble bed hydrogenation reactors. Both of them are provided with a nickel-based catalyst layer. The first hydrogenation reactor and / or the second hydrogenation reactor are also provided with a co-catalyst feed end.

[0037] An aldehyde feed end is provided to supply more aldehyde to the 1,4-butynediol synthesis reactor and / or the first hydrogenation reactor; the aldehyde feed end is located at the inlet of the 1,4-butynediol synthesis reactor, and / or at the top, upper, middle and / or bottom of the first hydrogenation reactor; preferably located in the middle of the first hydrogenation reactor;

[0038] And a distillation unit located downstream of the hydrogenation reactor, the distillation unit including a heavy removal tower, a methanol recovery tower located downstream of the heavy removal tower, and a light removal tower located downstream of the methanol recovery tower.

[0039] The tower of the first hydrogenation reactor is divided into three equal parts: the part furthest from the ground is called the upper part, the part closest to the ground is called the lower part, and the part between the upper and lower parts is called the middle part.

[0040] Beneficial effects

[0041] The 1,4-butanediol preparation system provided by this invention uses a two-stage bubbling bed hydrogenation reactor, which can effectively extend the catalyst's service life. Furthermore, based on this system, by setting an aldehyde feed end and a co-catalyst feed end, a system for co-producing alkyl-1,4-butanediol can be obtained, achieving the co-production of 1,4-butanediol and alkyl-1,4-butanediol. The proportion of alkyl-1,4-butanediol in the product can even be adjusted, reaching a maximum of 25 wt%. Attached Figure Description

[0042] Figure 1 A schematic diagram of the 1,4-butanediol preparation system provided in Example 1;

[0043] Figure 2A schematic diagram of the co-production system of 1,4-butanediol and alkyl-1,4-butanediol provided in Example 2;

[0044] Figure label:

[0045] R1 - 1,4-Butynediol (BYD) synthesis reactor; T1 - Formaldehyde circulation tower; R2 - First hydrogenation reactor; R3 - Second hydrogenation reactor; C1 - Heavy weight removal tower; C2 - Methanol recovery tower; C3 - Light weight removal tower;

[0046] A - First aldehyde feed end; B - Second aldehyde feed end; C - Third aldehyde feed end; D - Fourth aldehyde feed end; E - Fifth aldehyde feed end; F - Co-catalyst feed end. Detailed Implementation

[0047] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0048] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0049] Example 1

[0050] like Figure 1 The 1,4-butanediol preparation system shown includes:

[0051] 1,4-Butynediol synthesis reactor R1;

[0052] Formaldehyde circulation tower T1 is located downstream of the 1,4-butynediol synthesis reactor;

[0053] The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are located downstream of the formaldehyde circulation tower T1. The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are connected in series. The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are bubble bed hydrogenation reactors, and both are equipped with nickel-based catalyst layers inside.

[0054] And a distillation unit located downstream of the hydrogenation reactor, the distillation unit including: a heavy removal tower C1, a methanol recovery tower C2 located downstream of the heavy removal tower C1, and a light removal tower C3 located downstream of the methanol recovery tower C2.

[0055] The 1,4-butynediol synthesis reactor R1 is equipped with a feed inlet (e.g., formaldehyde feed inlet, acetylene feed inlet), a discharge outlet, a formaldehyde circulation inlet, and a tail gas outlet;

[0056] Formaldehyde circulation tower T1 is equipped with an inlet and an outlet;

[0057] The outlet of the 1,4-butynediol synthesis reactor R1 is connected to the inlet of the formaldehyde circulation tower T1, and the outlet of the formaldehyde circulation tower T1 is connected to the inlet of the 1,4-butynediol synthesis reactor R1 or the formaldehyde circulation inlet.

[0058] The first hydrogenation reactor R2 is equipped with an inlet and an outlet, and the outlet of the formaldehyde circulation tower T1 is connected to the inlet of the first hydrogenation reactor R2.

[0059] The second hydrogenation reactor R3 is equipped with an inlet and an outlet. The outlet of the first hydrogenation reactor R2 is connected to the inlet of the second hydrogenation reactor R3, and the outlet of the second hydrogenation reactor R3 is connected to the distillation unit.

[0060] The feed inlets of the first hydrogenation reactor R2 include the feed inlet for the reaction products of the 1,4-butenediol synthesis reactor and the hydrogen feed inlet.

[0061] The feed inlet of the second hydrogenation reactor R3 includes the feed inlet of the product from the first hydrogenation reactor and the hydrogen feed inlet.

[0062] The heavy removal tower C1, methanol recovery tower C2, and light removal tower C3 are plate distillation towers.

[0063] The heavy phase removal tower C1, methanol recovery tower C2, and light phase removal tower C3 are all equipped with a feed inlet, a gas phase outlet, and a liquid phase outlet.

[0064] The outlet of the second hydrogenation reactor R3 is connected to the inlet of the heavy phase removal tower C1. The gas phase outlet of the heavy phase removal tower C1 is connected to the inlet of the methanol recovery tower C2. The liquid phase outlet of the methanol recovery tower C2 is connected to the inlet of the light phase removal tower C3.

[0065] Heavy components are collected from the liquid phase outlet of the heavy removal tower C1;

[0066] Methanol is collected from the gas phase outlet of methanol recovery tower C2 and connected to the methanol oxidation to formaldehyde unit.

[0067] 1,4-Butanediol is discharged from the liquid phase outlet of the light phase removal tower C3, while other alcohols besides methanol are discharged from the gas phase outlet of the light phase removal tower C3.

[0068] Formaldehyde from the methanol oxidation unit reacts with acetylene in the 1,4-butynediol synthesis reactor R1, completely converting the acetylene. The effluent from reactor R1 passes through formaldehyde recycling tower T1 to recover formaldehyde and is returned to reactor R1 for further reaction. The formaldehyde-free stream from the bottom of formaldehyde recycling tower T1 undergoes a two-stage hydrogenation reaction in the first hydrogenation reactor R2 and the second hydrogenation reactor R3 to produce only 1,4-butanediol (BDO), thus achieving dedicated BDO production. 1,4-Butynediol (BYD) and hydrogen are converted into the effluent from R3 under the action of a nickel-based catalyst, containing BDO, methanol, impurity alcohols (butanol, propanol, etc.), and heavy components. The R3 feed first passes through the heavy component removal tower C1 to remove salts and heavy components, then passes through the methanol recovery tower C2 to recover methanol. The bottom stream of the methanol recovery tower C2 enters the light component removal tower C3 to separate impurities, alcohols, and water. The bottom stream of the light component removal tower C3 yields a high-concentration (not less than 99.0 wt%) BDO product.

[0069] This embodiment uses a two-stage bubbling bed hydrogenation reactor, which effectively extends the catalyst's service life, extending the catalyst replacement cycle to over one year. Based on this system, a system for co-producing alkyl-1,4-butanediol can be obtained.

[0070] Example 2

[0071] like Figure 2 The system shown for the co-production of 1,4-butanediol and alkyl-1,4-butanediol includes:

[0072] 1,4-Butynediol synthesis reactor R1;

[0073] Formaldehyde circulation tower T1 is located downstream of the 1,4-butynediol synthesis reactor;

[0074] The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are located downstream of the formaldehyde circulation tower T1. The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are connected in series. The first hydrogenation reactor R2 and the second hydrogenation reactor R3 are bubble bed hydrogenation reactors. Both are equipped with nickel-based catalyst layers. The first hydrogenation reactor R2 and / or the second hydrogenation reactor R3 are also equipped with a co-catalyst feed end F.

[0075] One or more (e.g., two, three, four or five) aldehyde feed ends, which are used to supply more aldehyde to the 1,4-butenediol synthesis reactor and / or the first hydrogenation reactor;

[0076] In one embodiment, the first aldehyde feeding end A is located at the feed inlet of the 1,4-butynediol synthesis reactor R1;

[0077] In one embodiment, the second aldehyde feed end B is located at the top of the first hydrogenation reactor R2;

[0078] In one embodiment, the third aldehyde feed end C is located above the first hydrogenation reactor R2;

[0079] In one embodiment, the fourth aldehyde feed end D is located in the middle of the first hydrogenation reactor R2;

[0080] In one embodiment, the fifth aldehyde feed end E is located at the bottom of the first hydrogenation reactor R2;

[0081] And a distillation unit located downstream of the hydrogenation reactor, the distillation unit including: a heavy removal tower C1, a methanol recovery tower C2 located downstream of the heavy removal tower C1, and a light removal tower C3 located downstream of the methanol recovery tower C2.

[0082] The 1,4-butynediol synthesis reactor R1 is equipped with a feed inlet (e.g., formaldehyde feed inlet, acetylene feed inlet), a discharge outlet, a formaldehyde circulation inlet, and a tail gas outlet;

[0083] Formaldehyde circulation tower T1 is equipped with a feed inlet and a discharge outlet, the first hydrogenation reactor R2 is equipped with a feed inlet and a discharge outlet, and the second hydrogenation reactor R3 is equipped with a feed inlet and a discharge outlet.

[0084] When only 1,4-butanediol is produced, the outlet of the 1,4-butynediol synthesis reactor R1 is connected to the inlet of the formaldehyde circulation tower T1, and the outlet of the formaldehyde circulation tower T1 is connected to the inlet of the 1,4-butynediol synthesis reactor R1 or the formaldehyde circulation inlet.

[0085] When alkyl-1,4-butanediol is also generated, close the valve on the connecting pipeline between the outlet of the 1,4-butynediol synthesis reactor R1 and the inlet of the formaldehyde circulation tower T1, and connect the outlet of the 1,4-butynediol synthesis reactor R1 to the inlet of the first hydrogenation reactor.

[0086] The outlet of the first hydrogenation reactor R2 is connected to the inlet of the second hydrogenation reactor R3, and the outlet of the second hydrogenation reactor R3 is connected to the distillation unit.

[0087] The feed inlets of the first hydrogenation reactor R2 include the feed inlet for the reaction products of the 1,4-butynediol synthesis reactor and the hydrogen feed inlet.

[0088] The feed inlet of the second hydrogenation reactor R3 includes the feed inlet of the product from the first hydrogenation reactor and the hydrogen feed inlet.

[0089] The heavy removal tower C1, methanol recovery tower C2, and light removal tower C3 are plate distillation towers.

[0090] The heavy phase removal tower C1, methanol recovery tower C2, and light phase removal tower C3 are all equipped with a feed inlet, a gas phase outlet, and a liquid phase outlet.

[0091] The outlet of the second hydrogenation reactor R3 is connected to the inlet of the heavy phase removal tower C1. The gas phase outlet of the heavy phase removal tower C1 is connected to the inlet of the methanol recovery tower C2. The liquid phase outlet of the methanol recovery tower C2 is connected to the inlet of the light phase removal tower C3.

[0092] Heavy components are collected from the liquid phase outlet of the heavy removal tower C1;

[0093] Methanol is collected from the gas phase outlet of methanol recovery tower C2 and connected to the methanol oxidation to formaldehyde unit.

[0094] The liquid phase outlet of the light phase removal tower C3 produces 1,4-butanediol and alkyl-1,4-butanediol, while the gas phase outlet of the light phase removal tower C3 produces alcohols other than methanol.

[0095] Excess hydrogen in the hydrogenation reactor is separated into gas and liquid in a known manner and then circulated back to the feed inlets of the first hydrogenation reactor R2 and the second hydrogenation reactor R3 (not shown in the figure) via a compressor.

[0096] Taking the co-production of 1,4-butanediol and methyl-1,4-butanediol as an example, formaldehyde from the methanol oxidation unit reacts with acetylene in the 1,4-butynediol synthesis reactor R1. The effluent from the 1,4-butenediol synthesis reactor R1 directly enters the first hydrogenation reactor R2. Fresh formaldehyde is added to the 1,4-butenediol synthesis reactor R1 and / or the first hydrogenation reactor R2 through the aldehyde feed end to adjust the feed ratio and increase the proportion of MBDO. A co-catalyst (such as n-butylamine, trimethylamine, ethylene glycolamine, or other organic or inorganic amine / ammonium salts, or alkaline compounds, such as one or more oxides or hydroxides of lithium, sodium, potassium, etc.) is added to the first hydrogenation reactor R2 and / or the second hydrogenation reactor R3. After two-stage hydrogenation reactions, 1,4-butynediol (BYD), formaldehyde, and hydrogen are converted into R3 effluent under the combined action of nickel-based catalyst and co-catalyst. This effluent contains 1,4-butanediol (BDO), methyl-1,4-butanediol (MBDO), methanol, impurity alcohols (butanol, propanol, etc.), and heavy components. The R3 effluent first passes through the deweighting tower C1 to remove salts and heavy components, and then passes through the methanol recovery tower C2 to recover methanol. The methanol recovered at the top of the tower is directly sent to the methanol oxidation unit to be converted into formaldehyde and then reintroduced into the system. The methanol recovery tower C2 bottom stream enters the light alcohol removal tower C3 to complete the separation of fusel oil and water, and the BDO product containing MBDO is obtained in the bottom of the light alcohol removal tower C3.

[0097] By adjusting the formaldehyde addition amount at the aldehyde feeding end, a BDO product containing up to 25wt% MBDO can be obtained.

[0098] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

A system for preparing 1,1,4-butanediol, characterized in that, The preparation system includes: 1,4-Butynediol synthesis reactor; Formaldehyde circulation tower located downstream of the 1,4-butynediol synthesis reactor; The first hydrogenation reactor and the second hydrogenation reactor are located downstream of the formaldehyde circulation tower. The first hydrogenation reactor and the second hydrogenation reactor are connected in series. The first hydrogenation reactor and the second hydrogenation reactor are bubble bed hydrogenation reactors, and both are equipped with nickel-based catalyst layers inside. And a distillation unit located downstream of the hydrogenation reactor.

2. The preparation system according to claim 1, characterized in that, The 1,4-butynediol synthesis reactor is equipped with a feed inlet, a discharge outlet, and a formaldehyde circulation inlet. The formaldehyde circulation tower is equipped with an inlet and an outlet; The outlet of the 1,4-butynediol synthesis reactor is connected to the inlet of the formaldehyde circulation tower, and the outlet of the formaldehyde circulation tower is connected to the inlet of the 1,4-butynediol synthesis reactor or the formaldehyde circulation inlet.

3. The preparation system according to claim 2, characterized in that, The first hydrogenation reactor is provided with an inlet and an outlet, and the outlet of the formaldehyde circulation tower is connected to the inlet of the first hydrogenation reactor. The second hydrogenation reactor is provided with an inlet and an outlet. The outlet of the first hydrogenation reactor is connected to the inlet of the second hydrogenation reactor, and the outlet of the second hydrogenation reactor is connected to the distillation unit.

4. The preparation system according to claim 3, characterized in that, The feed inlet of the first hydrogenation reactor includes the feed inlet of the reaction product of the 1,4-butynediol synthesis reactor and the hydrogen feed inlet. The feed inlet of the second hydrogenation reactor includes the feed inlet of the product from the first hydrogenation reactor and the hydrogen feed inlet.

5. The preparation system according to claim 1, characterized in that, The distillation unit includes: a heavy removal tower, a methanol recovery tower located downstream of the heavy removal tower, and a light removal tower located downstream of the methanol recovery tower.

6. The preparation system according to claim 5, characterized in that, The heavy removal tower, methanol recovery tower, and / or light removal tower are plate distillation towers.

7. The preparation system according to claim 5, characterized in that, The heavy phase removal tower, methanol recovery tower, and light phase removal tower are all equipped with a feed inlet, a gas phase outlet, and a liquid phase outlet. The outlet of the second hydrogenation reactor is connected to the inlet of the heavy phase removal tower, the gas phase outlet of the heavy phase removal tower is connected to the inlet of the methanol recovery tower, and the liquid phase outlet of the methanol recovery tower is connected to the inlet of the light phase removal tower. Furthermore, the heavy components are collected from the liquid phase outlet of the de-heavy tower; Methanol is collected from the gas phase outlet of the methanol recovery tower and connected to the methanol oxidation to formaldehyde unit. The liquid phase outlet of the light-light removal tower produces 1,4-butanediol, and the gas phase outlet of the light-light removal tower produces alcohols other than methanol. A system for the co-production of 8,1,4-butanediol and alkyl-1,4-butanediol, characterized in that, The system includes the 1,4-butanediol preparation system according to any one of claims 1-7, wherein the 1,4-butanediol preparation system may or may not contain a formaldehyde circulation tower; The outlet of the 1,4-butynediol synthesis reactor is connected to the inlet of the first hydrogenation reactor. The system includes an aldehyde feed end for supplying more aldehyde to the 1,4-butenediol synthesis reactor and / or the first hydrogenation reactor; The first hydrogenation reactor and / or the second hydrogenation reactor are also provided with a catalyst feed end.

9. The system according to claim 8, characterized in that, The aldehyde feed end is located at the inlet of the 1,4-butynediol synthesis reactor, and / or at the top, upper, middle and / or bottom of the first hydrogenation reactor. A system for the co-production of 10,1,4-butanediol and alkyl-1,4-butanediol, characterized in that, The system includes: 1,4-Butynediol synthesis reactor; Formaldehyde circulation tower located downstream of the 1,4-butynediol synthesis reactor; The first hydrogenation reactor and the second hydrogenation reactor are located downstream of the formaldehyde circulation tower. The first hydrogenation reactor and the second hydrogenation reactor are connected in series. The first hydrogenation reactor and the second hydrogenation reactor are bubble bed hydrogenation reactors. Both of them are provided with a nickel-based catalyst layer. The first hydrogenation reactor and / or the second hydrogenation reactor are also provided with a co-catalyst feed end. An aldehyde feed end is provided to supply more aldehyde to the 1,4-butynediol synthesis reactor and / or the first hydrogenation reactor; the aldehyde feed end is located at the inlet of the 1,4-butynediol synthesis reactor, and / or at the top, upper, middle and / or bottom of the first hydrogenation reactor. And a distillation unit located downstream of the hydrogenation reactor, the distillation unit including a heavy removal tower, a methanol recovery tower located downstream of the heavy removal tower, and a light removal tower located downstream of the methanol recovery tower.

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