Aldehyde liquid phase hydrogenation reaction system and method

Abstract

The present application provides an aldehyde liquid phase hydrogenation reaction system, which is provided with a novel liquid phase hydrogenation reactor. The reactor is provided with upper and lower column catalyst bed layers, and the outer wall is provided with baffles; the bed support structure and the redistributor are arranged between the upper and lower column catalyst bed layers; the support porcelain ball and the wire mesh layer are arranged below the lower column catalyst bed layer; the first fresh hydrogen inlet is arranged at the top of the cylinder, and the liquid phase inlet is arranged below the first fresh hydrogen inlet; the second fresh hydrogen inlet is arranged above the redistributor; the boiler water inlet and the water vapor mixed outlet are arranged in the upper and lower column catalyst bed layers, respectively; the bottom of the cylinder is provided with a liquid phase outlet; the gas phase outlet is arranged below the lower column catalyst bed layer; the fresh hydrogen is input through the first fresh hydrogen inlet and the second fresh hydrogen inlet; the water vapor mixed outlet is connected with the steam drum; the liquid phase outlet and the gas phase outlet are connected with the separation tank, and the top of the separation tank is connected with the vent gas cooler. The present application avoids the problem of temperature rising, produces high-grade steam as by-product, and saves energy and reduces consumption.

Description

Technical Field

[0001] This invention relates to the field of aldehyde hydrogenation, and more specifically to a liquid-phase hydrogenation reaction system and method for aldehydes. Background Technology

[0002] n-Butanol and 2-ethylhexanol (2-EH) are important chemical raw materials widely used in coatings, resins, plasticizers, and other fields, and the market demand for both continues to grow. One of the core processes in the production of n-butanol and 2-ethylhexanol is the hydrogenation reaction of butyraldehyde or octenal (2-EH precursors). Currently, domestic butyraldehyde / octenal hydrogenation processes include gas-phase hydrogenation and liquid-phase hydrogenation processes.

[0003] Gas-phase hydrogenation processes (such as CN103055766B) require the liquid-phase butyraldehyde or octenal feedstock to be heated and vaporized before entering the subsequent gas-phase hydrogenation reactor. This consumes a large amount of heating steam and necessitates the use of a circulating hydrogen compressor, which consumes significant amounts of electricity or superheated steam. These processes suffer from significant drawbacks, including high energy consumption, substantial safety hazards, and high investment and maintenance costs. Therefore, in recent years, liquid-phase hydrogenation processes have gradually replaced gas-phase hydrogenation processes as the mainstream due to their lower energy consumption, lower initial investment, and simpler operation.

[0004] However, traditional liquid-phase hydrogenation processes typically employ two or three stages of adiabatic trickle bed reactors connected in series (e.g., Figure 3 The system shown has 65%–95% of its fresh hydrogen entering the primary reactor, with the remaining fresh hydrogen entering the secondary and tertiary reactors. The secondary and tertiary reactors do not have separate heat exchangers. Liquid aldehyde feedstock and hydrogen undergo an exothermic hydrogenation reaction in a catalyst-filled trickle bed reactor. In an external heat exchanger, the heat from the circulating liquid is used to generate low-pressure steam. Simultaneously, the cooled circulating liquid is mixed with fresh feedstock and pumped back into the reactor system. The heat of reaction is extracted from the reactor through a large amount of circulating reaction products and feedstock. Forced circulation is achieved by external heat exchange of the circulating liquid and the generation of low-grade steam (typically 0.2–0.3 MPaG), requiring a high-power circulation pump. This existing system uses two or three stages of adiabatic trickle bed reactors connected in series. The exothermic reaction experiences temperature runaway in an adiabatic environment, posing a risk of temperature surge. Furthermore, the external heat exchange of the circulating liquid results in byproduct steam with a grade below 0.3 MPaG, making recovery difficult. In addition, the complex equipment and the multi-stage series connection with the external circulation pump increase energy consumption and maintenance costs.

[0005] Therefore, existing aldehyde hydrogenation processes cannot simultaneously achieve efficient heat transfer, temperature control, and steam grade improvement in liquid-phase hydrogenation, necessitating the research of new equipment to overcome these shortcomings.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides an aldehyde liquid-phase hydrogenation reaction system that effectively avoids the temperature runaway problem of the adiabatic reactor in existing liquid-phase reaction systems, improves the grade of by-product steam, and eliminates the need for a vaporization tower and circulating hydrogen compressor required for gas-phase hydrogenation, significantly reducing steam consumption. The system has low overall investment and energy consumption, making it suitable for industrial application.

[0008] The basic concept of the technical solution adopted in this invention is as follows:

[0009] An aldehyde liquid-phase hydrogenation reaction system includes an inlet tank, a hydrogen preheater, a steam drum, a liquid-phase hydrogenation reactor, a feed pump, a separation tank, a purge gas cooler, and a boiler water circulation pump.

[0010] The liquid-phase hydrogenation reactor includes: (a) a shell assembly: a cylindrical body and end caps at its upper and lower ends; (b) a catalyst system: an upper tube catalyst bed and a lower tube catalyst bed are coaxially arranged inside the cylindrical body, and baffles are installed tightly on the outer wall of each bed. (c) Interbed structure: A bed support structure and redistributor are provided from top to bottom between the upper tube catalyst bed and the lower tube catalyst bed;

[0011] (d) Bottom structure: A supporting ceramic ball and wire mesh layer are installed below the catalyst bed in the following tube; (e) Fluid distribution system: A first fresh hydrogen inlet is provided at the top of the cylinder, and a liquid phase inlet is provided below the first fresh hydrogen inlet at the top; a second fresh hydrogen inlet is provided above the redistributor; (f) Boiler water circulation system: Boiler water inlet and steam mixing outlet are respectively provided in the upper tube catalyst bed and the lower tube catalyst bed;

[0012] (g) Product outlet: A liquid phase outlet connected to a vortex breaker is provided at the bottom of the cylinder; a gas phase outlet is provided below the catalyst bed in the following tube;

[0013] The liquid phase aldehyde input is connected to the liquid phase inlet via a liquid inlet tank and a feed pump; the fresh hydrogen input is connected to the first fresh hydrogen inlet and the second fresh hydrogen inlet via a hydrogen preheater.

[0014] The boiler water inlet is connected to the boiler water inlet of the upper tube catalyst bed and the lower tube catalyst bed, respectively, via the steam drum and boiler water circulation pump. It also connects to the outlet of the boiler water circulation pump and the upper tube catalyst bed.

[0015] The steam mixing outlet of the catalyst bed and the following tubular catalyst bed is connected to the steam drum;

[0016] The liquid phase outlet and gas phase outlet are connected to the separation tank. The top of the separation tank is connected to the purge gas cooler, and the bottom is connected to the product output end.

[0017] In one approach, the baffles are a continuous spiral structure with a pitch of 1.5 to 2 times the outer diameter of the reactor cylinder.

[0018] In one embodiment, the bed support structure comprises, from top to bottom, supporting ceramic balls, a wire mesh layer, and a supporting grid.

[0019] In one configuration, the top of the upper tube catalyst bed is provided with a first boiler water inlet and the bottom with a first steam-water mixing outlet; the top of the lower tube catalyst bed is provided with a second boiler water inlet and the bottom with a second steam-water mixing outlet.

[0020] In one approach, a tube sheet is installed on the upper part of the upper tube catalyst bed to fix the tubes.

[0021] In one approach, the first fresh hydrogen inlet is connected to a gas distributor, and the liquid inlet is connected to a liquid distributor.

[0022] In one approach, the baffle rises in a spiral at a 30-45° angle relative to the horizontal direction, and its spiral surface is continuous in the axial direction and has a uniform thickness at all points, with a deviation of ≤±10%.

[0023] In one approach, manholes are provided in the portion of the cylinder between the upper tube catalyst bed and the lower tube catalyst bed, as well as in the lower portion of the wire mesh layer located below the lower tube catalyst bed.

[0024] This invention provides a method for liquid-phase hydrogenation of aldehydes, wherein the method is operated in any of the aforementioned liquid-phase hydrogenation reaction systems for aldehydes, converting aldehydes into alcohols.

[0025] In one embodiment, the aldehyde is selected from butyraldehyde or octenal; the outlet pressure of the feed pump is controlled to be 2.6~2.75 MPaG; the hydrogen gas input from the fresh hydrogen input terminal passes through a hydrogen preheater and is heated to 105~140°C by low-pressure steam entering from the low-pressure steam input terminal.

[0026] As one approach, 65% to 95% of the fresh hydrogen is controlled to enter through the first fresh hydrogen inlet, while the remaining fresh hydrogen enters through the second fresh hydrogen inlet.

[0027] One method is to control the reaction temperature of the liquid-phase hydrogenation reactor by adjusting the pressure of the steam drum. For every 0.1 MPaG increase in pressure, the reaction temperature rises by 8-10°C.

[0028] In one embodiment, the catalyst composition packed in the upper tube catalyst bed and the lower tube catalyst bed is as follows: when the aldehyde is propionaldehyde, butyraldehyde, 2-methylbutyraldehyde or 3-hydroxypropionaldehyde, a Cu-Ni-Zr-Ce / SiO2-Al2O3 catalyst is used; when the aldehyde is octenal, a Ni-Cu-K / SiO2-Al2O3-h-BN catalyst is used.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. The core of the aldehyde liquid-phase hydrogenation reaction system described in this invention lies in the use of a novel liquid-phase hydrogenation reactor, which is a cold-wall reactor. Through the integrated design of dual-bed catalysis and tube heat exchange, as well as precise temperature control of the steam drum, safe and efficient production is achieved.

[0031] This invention is based on a novel liquid-phase hydrogenation reactor, and forms a complete process system and flow that is efficient, energy-saving, and safe.

[0032] 2. This invention significantly simplifies the process flow, shortens the process and reduces investment by using in-unit heat exchange. The reaction heat is directly absorbed by the shell-side boiler water, and the temperature is regulated by the steam drum pressure (each 0.1 MPaG of pressure corresponds to a temperature rise of 8~10℃), achieving dynamic balance. This avoids the risk of overheating while producing higher-quality steam, achieving the production goals of safety, low consumption and environmental protection.

[0033] 3. The system described in this invention produces 0.45~0.6 MPaG steam as a byproduct. The high-grade steam can be recovered and directly used in the distillation process within the device, reducing energy consumption by 30%.

[0034] 4. The liquid phase hydrogenation reactor in the system described in this invention is equipped with baffles (tilt angle 30~45°), which forces the fluid to turbulent, enhances the heat transfer effect, improves the heat transfer efficiency, and the dual-bed design eliminates the external circulation system, simplifies the structure, and reduces equipment investment.

[0035] 5. In the system described in this invention, hydrogen is injected into the liquid phase hydrogenation reactor in two stages, which helps to promote the forward reaction and improves the aldehyde conversion rate.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0037] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0038] Figure 1 This is a schematic diagram of the structure of the aldehyde liquid-phase hydrogenation reaction system described in this invention.

[0039] Figure 2 yes Figure 1The diagram shows the structure of the liquid-phase hydrogenation reactor.

[0040] Figure 3 This is a schematic diagram of the structure of the liquid-phase hydrogenation reactor for butyraldehyde used in existing technology.

[0041] Figure 4 This is a schematic diagram of the structure of the liquid-phase hydrogenation reactor for octenal used in existing technology.

[0042] Figure 5 yes Figure 2 A schematic diagram of the baffle plate shown.

[0043] Marked in the image:

[0044] T1 - Liquid phase aldehyde input; T2 - Fresh hydrogen input; T3 - Product output; T4 - Low-pressure steam input; T5 - Low-pressure steam condensate output; T6 - Medium-pressure steam output; T7 - ​​Boiler water input; T8 - Steam drum blowdown; T9 - Circulating water inlet; T10 - Circulating water outlet; T11 - Purge gas outlet; T12 - Liquid inlet tank; T13 - Hydrogen preheater; T14 - Steam drum; T15 - Liquid phase hydrogenation reactor; T16 - Feed pump; T17 - Separator; T18 - Purge gas cooler; T19 - Boiler water circulation pump;

[0045] 1-Head; 2-Cylinder; 3-First Fresh Hydrogen Inlet; 4-Gas Distributor; 5-Liquid Distributor; 6-Liquid Phase Inlet; 7-Tube Sheet; 8-Upper Tube Catalyst Bed; 9-First Boiler Water Inlet; 10-First Boiler Steam-Water Mixing Outlet; 11-Supporting Ceramic Ball Layer; 12-Wire Mesh Layer; 13-Supporting Grid; 14-Manhole; 15-Second Fresh Hydrogen Inlet; 16-Redistributor; 17-Lower Tube Catalyst Bed; 18-Second Boiler Water Inlet; 19-Second Boiler Steam-Water Mixing Outlet; 20-Vortex Breaker; 21-Liquid Phase Outlet; 22-Baffle Plate; 23-Gas Phase Outlet;

[0046] 101-Circulating liquid heat exchanger; 102-Circulating liquid pump; 103-First-stage reactor; 104-Second-stage reactor; 105-Purge gas condenser; 106-Separation tank; R01-Fresh hydrogen; R02-Fresh butyraldehyde; R03-Boiler water; R04-Low-pressure steam; R05-Circulating feed water; R06-Circulating return water; R07-Purge gas; R08-Crude butanol;

[0047] 201 - Fresh hydrogen; 202 - Fresh octenal; 203 - Boiler water; 204 - Low-pressure steam; 205 - Circulating feed water; 206 - Circulating return water; 207 - Purge gas; 208 - Octanol; 209 - Circulating liquid heat exchanger; 210 - Circulating liquid pump; 211 - Primary reactor; 212 - Secondary reactor; 213 - Refining reactor; 214 - Purge gas condenser; 215 - Separator;

[0048] y is the outer diameter of the reactor cylinder 2. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] This invention designs a process flow for a liquid-phase hydrogenation reactor that integrates dual-bed catalysis and heat exchange. By coupling the reaction heat exchange structure, using steam drum temperature control technology and high-grade steam recovery, and simplifying the process design through system integration, it achieves the goals of improving production safety, reducing energy consumption, and reducing equipment investment. It relies on multiple core innovations to solve existing problems.

[0051] Example 1

[0052] An aldehyde liquid-phase hydrogenation reaction system, such as Figure 1 As shown, it includes the liquid inlet tank T12 and the hydrogen preheater.

[0053] T13, steam drum T14, liquid phase hydrogenation reactor T15, feed pump T16, separator T17, vent gas cooler T18, and boiler water circulation pump T19.

[0054] The structure of the liquid phase hydrogenation reactor T15 is as follows: Figure 2 As shown, it includes: (a) a shell assembly: a cold-walled cylinder 2 and end caps 1 at its upper and lower ends; (b) a catalyst system: an upper tube catalyst bed 8 and a lower tube catalyst bed coaxially arranged inside the cylinder 2.

[0055] Bed 17, with baffles 22 tightly installed on the outer wall of the corresponding part of the cylinder 2; (c) Inter-bed structure: the upper tube catalyst bed 8 and the lower tube catalyst bed 17 are connected from top to bottom

[0056] The bed support structure and redistributor 16 are installed below;

[0057] (d) Bottom structure: A supporting ceramic ball 11 and a wire mesh layer 12 are provided below the catalyst bed 17; (e) Fluid distribution system: A first fresh hydrogen inlet 3 is provided at the top of the cylinder 2, and the upper part of the first fresh hydrogen inlet...

[0058] A liquid phase inlet 6 is provided below the fresh hydrogen inlet 3; a second fresh hydrogen inlet 15 is provided above the redistributor 16; (f) Boiler water circulation system: the upper tube catalyst bed 8 and the lower tube catalyst bed 17 are respectively provided with a boiler water inlet (one or more) and a steam mixing outlet (one or more);

[0059] (g) Product outlet: A liquid phase outlet 21 connected to the vortex breaker 20 is provided at the bottom of the cylinder 2; the following pipes

[0060] A gas phase outlet 23 is provided below the catalyst bed 17;

[0061] The liquid phase aldehyde input terminal T1 is connected to the liquid phase inlet 6 via the liquid inlet tank T12 and the feed pump T16; the fresh hydrogen input terminal T2 is connected to the first fresh hydrogen inlet 3 and the second fresh hydrogen inlet 15 via the hydrogen preheater T13.

[0062] Boiler water inlet T7 connects sequentially to the upper tubes via steam drum T14 and boiler water circulation pump T19.

[0063] The boiler water inlet of catalyst bed 8 and the lower tube catalyst bed 17, the outlet of boiler water circulation pump T19, and the steam mixing outlet of the upper tube catalyst bed 8 and the lower tube catalyst bed 17 are all connected to the steam drum T14.

[0064] Liquid phase outlet 21 and gas phase outlet 23 are connected to separator T17. The top of separator T17 is connected to vent gas cooler T18 and the bottom is connected to product output end T3.

[0065] As an example, such as Figure 5 As shown, the baffle 22 has a continuous spiral structure with a pitch of 1.5 to 2 times the outer diameter of the reactor cylinder 2. The baffle 22 spirals upward at a 30-45° angle relative to the horizontal direction, and its spiral surface is continuous in the axial direction and has a uniform thickness throughout, with a deviation of ≤±10%.

[0066] The baffle 22 can effectively achieve high heat exchange efficiency with low fluid resistance and achieve good vibration resistance, reducing noise caused by high air velocity during operation. The pitch is 1.5 to 2 times the outer diameter of the cylinder 2.

[0067] As an example, the bed support structure includes, from top to bottom, supporting ceramic balls 11, a wire mesh layer 12, and a supporting grid 13.

[0068] The upper tube catalyst bed 8 has a first boiler water inlet 9 at the top and a first steam-water mixing outlet 10 at the bottom; the lower tube catalyst bed 17 has a second boiler water inlet 18 at the top and a second steam-water mixing outlet 19 at the bottom. The upper tube catalyst bed 8 is provided with a tube sheet 7 for fixing the tubes.

[0069] The first fresh hydrogen inlet 3 is connected to the gas distributor 4, and the liquid inlet 6 is connected to the liquid distributor 5.

[0070] As an example, the cylinder 2 has an upper tubular catalyst bed 8 and a lower tubular catalyst bed 17.

[0071] Manholes 14 are provided in the middle part and the lower part of the wire mesh layer 12 below the catalyst bed 17.

[0072] Furthermore, the baffle plate 22 spirals upward at a relative horizontal angle of 30-45° to guide and control the fluid flow and force the boiler water to flow in a turbulent state, thereby enhancing the heat transfer efficiency.

[0073] The supporting ceramic balls 11, the wire mesh layer 12 (including multiple layers of wire mesh), and the bed support grid 13 form a structure that supports the catalyst and can be replaced synchronously according to the catalyst's usage cycle.

[0074] In the system described in this invention, hydrogen and liquid aldehydes contact and undergo a hydrogenation reaction in the liquid-phase hydrogenation reactor T15 to generate alcohols. This reaction process is exothermic. To achieve high conversion rates and ensure production stability, the system of this invention abandons the traditional multi-stage series adiabatic reactors and external circulating heat exchange systems, and instead adopts a single reactor integrating the reaction and efficient heat exchange. The hydrogenation reaction of aldehydes releases a large amount of heat and heats up rapidly. Furthermore, since both aldehydes and hydrogen are flammable and explosive substances, operation under high temperature and pressure is extremely dangerous. However, in this invention, heat exchange is performed within the liquid-phase hydrogenation reactor T15, and boiler water is introduced through the boiler water circulation pump T19 to remove the heat of reaction. The by-product steam enters the steam drum T14, and the temperature of the reaction system is regulated by controlling the pressure of the steam drum T14, ensuring safe and efficient production.

[0075] The liquid-phase hydrogenation reactor T15 of this invention adopts a two-stage tubular packing of catalyst, which achieves a high conversion rate of aldehydes and ensures production stability, avoiding a series of problems such as low product yield and poor quality due to incomplete conversion.

[0076] The composition of the catalyst packed in the upper tube catalyst bed 8 and the lower tube catalyst bed 17 is as follows:

[0077] When using propionaldehyde, butyraldehyde, 2-methylbutyraldehyde, or 3-hydroxypropionaldehyde as raw materials for liquid-phase hydrogenation production, the catalyst selected is the supported catalyst Cu-Ni-Zr-Ce / SiO2-Al2O3 disclosed in patent CN202510389830.6. This catalyst has a Cu-Ni-Zr-Ce quaternary active component, with SiO2-Al2O3 as the support. Based on the total mass of the catalyst (100%), the copper content is 15%-25%, the nickel content is 1%-5%, and the zirconium and cerium each account for 1%-3%.

[0078] When the aldehyde is octenal, the catalyst is the Ni-Cu-K / SiO2-Al2O3-h-BN catalyst disclosed in patent CN202410895408.3, wherein the mass fraction of Ni element is 8%~15%, the mass fraction of Cu element is 1%~4%, the mass fraction of K element is 0.5%~3%, and the balance is a composite support of SiO2, Al2O3 and h-BN.

[0079] An example process for using the liquid-phase hydrogenation reactor of the present invention is as follows:

[0080] First, workers enter manhole 14 to load the catalyst and complete the catalyst heating and reduction in a hydrogen atmosphere. Then, 95% of the fresh hydrogen is introduced through the first fresh hydrogen inlet 3 and enters the cylinder 2 through the gas distributor 4. Liquid aldehydes are introduced through the liquid inlet 6 and enter the cylinder 2 through the liquid distributor 5. The fresh hydrogen and liquid aldehydes react in the upper tube catalyst bed 8 to produce alcohols. The reaction products and unreacted raw materials are redistributed through the redistributor 16 and contact the remaining 5% of fresh hydrogen entering from the second fresh hydrogen inlet 15 in the lower tube catalyst bed 17. The replenishment of reactants promotes the forward hydrogenation reaction, improving production efficiency. The final product is discharged through the vortex breaker 20 and the liquid outlet 21 and enters the next stage of operation.

[0081] During the reaction, the amount of hydrogen introduced per ton of product should be controlled to be 300~400 Nm³.

[0082] To remove the heat of reaction in a timely manner, the boiler water circulation pump T19 is started early before the reaction begins. Boiler water is introduced into the shell of the cylinder 2 from the first boiler water inlet 9 and the second boiler water inlet 18. The boiler water carries away the heat of reaction and the by-product steam of 0.45~0.6MPaG is discharged into the steam drum T14 from the first steam-water mixing outlet 10 and the second steam-water mixing outlet 19. During this process, the operating temperature of the reactor is controlled by the steam drum T14.

[0083] The aldehyde liquid-phase hydrogenation reaction method provided by the present invention operates in the above-mentioned aldehyde liquid-phase hydrogenation reaction system to convert aldehydes into alcohols, specifically, for example, hydrogenating butyraldehyde or octenal to produce butanol and octanol.

[0084] When the aldehyde is selected from butyraldehyde, the outlet pressure of the feed pump T16 is controlled to be 2.6~2.75 MPaG; the hydrogen gas input from the fresh hydrogen gas input terminal T2 is heated to 105~140°C by the low-pressure steam entering from the low-pressure steam input terminal T4 through the hydrogen preheater T13.

[0085] 65% to 95% of the fresh hydrogen is controlled to enter through the first fresh hydrogen inlet 3, and the remaining fresh hydrogen is controlled to enter through the second fresh hydrogen inlet 15.

[0086] The reaction temperature of the liquid phase hydrogenation reactor 15 is controlled by adjusting the pressure of the steam drum T14. For every 0.1 MPaG increase in pressure, the reaction temperature rises by 8~10℃.

[0087] This invention uses butyraldehyde and octenal as raw materials to introduce an example of the working case of the aldehyde liquid-phase hydrogenation reaction system as follows.

[0088] Example 1

[0089] Butyraldehyde enters the liquid tank T12 from the liquid phase aldehyde input end T1 for pressure stabilization and buffering, and is then pumped into the liquid phase inlet 6 of the liquid phase hydrogenation reactor T15 by the feed pump T16. The pressure at the outlet of the feed pump T16 is controlled at 2.6~2.75 MPaG. At the same time, fresh hydrogen enters the hydrogen preheater T13 (with low-pressure steam) from the fresh hydrogen input end T2. The fresh hydrogen is heated to 105~140℃ by the low-pressure steam. 95% of the fresh hydrogen enters from the first fresh hydrogen inlet 3 set in the head 1 at the upper end of the liquid phase hydrogenation reactor T15, and the remaining 5% of the fresh hydrogen enters from the second fresh hydrogen inlet 15 of the catalyst bed 17 below, realizing multi-point addition of hydrogen.

[0090] The catalyst is a supported catalyst with a quaternary active component of Cu-Ni-Zr-Ce and a support of SiO2-Al2O3. Based on the total mass of the catalyst (100%), the copper content is 15%-25%, the nickel content is 1%-5%, and the zirconium and cerium content are 1%-3% each.

[0091] Butyraldehyde and hydrogen first undergo a hydrogenation reaction in the upper tube catalyst bed 8 to produce alcohols and some side reactions. Most of the hydrogen is consumed in this stage of the reaction. The reaction products and raw materials of the first stage enter the lower tube catalyst bed 17 along with fresh hydrogen through the redistributor 16 to react, allowing most of the remaining butyraldehyde to complete the hydrogenation reaction.

[0092] Hydrogenation is an exothermic reaction, and heat removal is crucial during this process. This invention utilizes a T14 steam drum.

[0093] It achieves three functions: removing reaction heat, producing by-product steam, and controlling reaction temperature. Low-pressure boiler water enters the steam drum T14 from the boiler water inlet T7 in a manner that controls the flow rate of the steam drum T14 by the liquid level. Then, it is pumped by the boiler water circulation pump T19 into the shell side of the upper tube catalyst bed 8 and the lower tube catalyst bed 17, removing reaction heat in an upward and downward manner. During this process, 0.45~0.6MPaG steam will be produced as a by-product.

[0094] The final product, butanol, enters the separator T17 from the liquid phase outlet 21 and the remaining small amount of hydrogen from the gas phase outlet 23. The top of the separator T17 is connected to the purge gas cooler T18. The gas phase after passing through the purge gas cooler T18 goes to the purge gas system as purge gas, and the liquid phase product is collected from the product output end T3 at the bottom of the separator T17.

[0095] Example 2

[0096] The difference from Example 1 is that in Example 2, the liquid-phase aldehyde used is octenal, and the hydrogen usage is adjusted to 450-550 Nm per ton of product. 3 .

[0097] When producing octenal by liquid-phase hydrogenation, the catalyst selected is a Ni-Cu-K / SiO2-Al2O3-h-BN catalyst, in which the mass fraction of Ni is 8%~15%, the mass fraction of Cu is 1%~4%, the mass fraction of K is 0.5%~3%, and the balance is a composite support of SiO2, Al2O3 and h-BN.

[0098] Comparative Example 1-1

[0099] The difference from Example 1 is that, as in Example 2, the following is used: Figure 3 The traditional butyraldehyde liquid-phase hydrogenation process shown in the diagram has two reactors connected in series, with the process parameters remaining constant.

[0100] Comparative Examples 1-2

[0101] The difference from Example 2 is that Comparative Examples 1-2 adopted the following... Figure 4 The traditional liquid-phase hydrogenation process of octenal shown in the figure has three reactors connected in series, and the process parameters remain unchanged.

[0102] Comparative Example 2-1

[0103] The difference from Example 1 is that the hydrogen distribution ratio in Comparative Example 2-1 is 90% fed through the first fresh hydrogen inlet 3 and 10% fed through the second fresh hydrogen inlet 15, with the rest remaining unchanged.

[0104] Comparative Example 2-2

[0105] The difference from Example 2 is that the hydrogen distribution ratio in Comparative Example 2-2 is 90% fed through the first fresh hydrogen inlet 3 and 10% fed through the second fresh hydrogen inlet 15, with the rest remaining unchanged.

[0106] Comparative Examples 2-3

[0107] The difference from Example 1 is that in Comparative Examples 2-3, the hydrogen distribution adopts a two-point addition distribution with 85% feed from the first fresh hydrogen inlet 3 and 15 feed from the second fresh hydrogen inlet 15, while the rest remains unchanged.

[0108] Comparative Examples 2-4

[0109] The difference from Example 2 is that in Comparative Examples 2-4, the hydrogen distribution adopts a two-point addition distribution with 85% feed from the first fresh hydrogen inlet 3 and 15 feed from the second fresh hydrogen inlet 15, while the rest remains unchanged.

[0110] Comparative Examples 2-5

[0111] The difference from Example 1 is that in Comparative Examples 2-5, the hydrogen distribution adopts a two-point addition distribution with 80% feed from the first fresh hydrogen inlet 3 and 20% feed from the second fresh hydrogen inlet 15, while the rest remains unchanged.

[0112] Comparative Examples 2-6

[0113] The difference from Example 2 is that in Comparative Examples 2-6, the hydrogen distribution adopts a two-point addition distribution with 80% feed from the first fresh hydrogen inlet 3 and 20% feed from the second fresh hydrogen inlet 15, while the rest remains unchanged.

[0114] Comparative Examples 2-7

[0115] The difference from Example 1 is that in Comparative Examples 2-5, the hydrogen distribution adopts a two-point addition distribution with 70% fed through the first fresh hydrogen inlet 3 and 30% fed through the second fresh hydrogen inlet 15, while the rest remains unchanged.

[0116] Comparative Examples 2-8

[0117] The difference from Example 2 is that in Comparative Examples 2-6, the hydrogen distribution adopts a first fresh hydrogen inlet 3 feeding 70%, a second fresh hydrogen inlet 15 feeding 30%, and the rest remains unchanged.

[0118] The operational results of the above embodiments and comparative examples are shown in Tables 1 and 2.

[0119] Table 1

[0120]

[0121] Table 2

[0122]

[0123] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An aldehyde liquid-phase hydrogenation reaction system, characterized in that, Including liquid inlet tank, hydrogen preheater, Steam drum, liquid phase hydrogenation reactor, feed pump, separator, purge gas cooler and boiler water circulation pump; The liquid-phase hydrogenation reactor includes: (a) Shell assembly: cylinder and its upper and lower end caps; (b) Catalyst system: The upper tube catalyst bed and the lower tube catalyst bed are coaxially arranged inside the cylinder, and baffles are installed on the outer wall of each bed. (c) Interbed structure: A bed support structure and redistributor are provided from top to bottom between the upper tube catalyst bed and the lower tube catalyst bed; (d) Bottom structure: A supporting ceramic ball and wire mesh layer are installed below the following tube catalyst bed; (e) Fluid distribution system: A first fresh hydrogen inlet is provided at the top of the cylinder, and a liquid phase inlet is provided below the first fresh hydrogen inlet at the top; a second fresh hydrogen inlet is provided above the redistributor; (f) Boiler water circulation system: Boiler water inlet and steam mixing outlet are respectively provided in the upper tube catalyst bed and the lower tube catalyst bed; (g) Product outlet: A liquid phase outlet connected to a vortex breaker is provided at the bottom of the cylinder; a gas phase outlet is provided below the catalyst bed in the following tube; The liquid phase aldehyde input is connected to the liquid phase inlet via a liquid inlet tank and a feed pump; the fresh hydrogen input is connected to the first fresh hydrogen inlet and the second fresh hydrogen inlet via a hydrogen preheater. The boiler water inlet is connected to the boiler water inlet of the upper tube catalyst bed and the lower tube catalyst bed after passing through the steam drum and the boiler water circulation pump. The outlet of the boiler water circulation pump and the steam-water mixing outlet of the upper tube catalyst bed and the lower tube catalyst bed are connected to the steam drum. The liquid phase outlet and the gas phase outlet are connected to the separation tank. The top of the separation tank is connected to the purge gas cooler, and the bottom is connected to the product output end. The baffles have a continuous spiral structure with a pitch of 1.5 to 2 times the outer diameter of the reactor cylinder. The top of the upper tube catalyst bed is provided with a first boiler water inlet, and the bottom is provided with a first steam-water mixing outlet; the top of the lower tube catalyst bed is provided with a second boiler water inlet, and the bottom is provided with a second steam-water mixing outlet. A tube sheet is installed at the top of the upper tube catalyst bed to fix the tubes; The first fresh hydrogen inlet is connected to the gas distributor, and the liquid inlet is connected to the liquid distributor; The baffle rises in a spiral at a 30-45° angle relative to the horizontal direction. Its spiral surface is continuous in the axial direction and has the same thickness everywhere, with a deviation of ≤±10%.

2. The aldehyde liquid-phase hydrogenation reaction system according to claim 1, characterized in that, The bed support structure, from top to bottom, includes supporting ceramic balls, a wire mesh layer, and a supporting grid.

3. The aldehyde liquid-phase hydrogenation reaction system according to any one of claims 1-2, characterized in that, Manholes are provided in the portion of the cylinder between the upper tube catalyst bed and the lower tube catalyst bed, and in the lower part of the wire mesh layer below the lower tube catalyst bed.

4. A method for liquid-phase hydrogenation of aldehydes, characterized in that, The method is operated in the aldehyde liquid-phase hydrogenation reaction system according to any one of claims 1-3, converting aldehydes into alcohols.

5. The method for liquid-phase hydrogenation of aldehydes according to claim 4, characterized in that, The aldehydes are selected from butyraldehyde or octenal; the outlet pressure of the feed pump is controlled at 2.6~2.75 MPaG; the hydrogen gas input from the fresh hydrogen input terminal passes through the hydrogen preheater and is heated to 105~140℃ by the low-pressure steam entering from the low-pressure steam input terminal.

6. The method for liquid-phase hydrogenation of aldehydes according to claim 5, characterized in that, 65% to 95% of the fresh hydrogen is controlled to enter through the first fresh hydrogen inlet, and the remaining fresh hydrogen is controlled to enter through the second fresh hydrogen inlet.

7. The method for liquid-phase hydrogenation of aldehydes according to claim 5, characterized in that, The reaction temperature of the liquid-phase hydrogenation reactor is controlled by adjusting the pressure of the steam drum. For every 0.1 MPaG increase in pressure, the reaction temperature rises by 8-10℃.

8. The method for liquid-phase hydrogenation of aldehydes according to claim 5, characterized in that, The catalysts packed in the upper and lower tube catalyst beds are composed of the following components: when the aldehyde is propionaldehyde, butyraldehyde, 2-methylbutyraldehyde, or 3-hydroxypropionaldehyde, a Cu-Ni-Zr-Ce / SiO2-Al2O3 catalyst is used; when the aldehyde is octenal, a Ni-Cu-K / SiO2-Al2O3-h-BN catalyst is used.

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