Multi-section quench trickle bed reaction system and reaction method for liquid phase hydrogenation of aldehyde and ketone

Abstract

The invention relates to a multi-section quench trickle bed reaction system and reaction method for liquid phase hydrogenation of aldehyde and ketone, the system comprises a multi-section quench liquid phase hydrogenation reactor filled with at least two sections of catalyst bed layers, a product circulating liquid inlet is arranged above each section of catalyst bed layer and is used for introducing a product circulating liquid into the corresponding catalyst bed layer; the adiabatic temperature rise of each section of the catalyst bed layer of the reactor is independently controlled by controlling the flow and the temperature of the circulating quenching liquid of each section of the catalyst bed layer; the method can effectively reduce the adiabatic temperature rise of the catalyst bed layer, prolong the service life of the catalyst, reduce the occurrence of side reactions, improve the product quality and yield, reduce the circulation volume of the liquid-phase product, and reduce the energy consumption. And a better hydrogenation effect can be realized by adopting a single trickle bed reactor, so that the equipment investment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and in particular relates to a multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones, which is suitable for the liquid phase hydrogenation process of aldehydes and ketones. Background Art

[0002] In the fine chemical, pharmaceutical chemical, coal chemical and petrochemical industries, hydrogenation reaction is a very common and important reaction, which is applicable to the hydrogenation process of hydrofining, olefins, aldehydes and ketones; among them, heavy oil hydrofining and olefins, aldehydes and ketones hydrogenation belong to two different hydrogenation reaction systems. The former mainly uses a sulfide catalyst (metal sulfide) to convert sulfur, nitrogen, oxygen (mainly C=O) and metals in heavy oil into H2S, NH3, H2O and metal sulfides under high temperature and high pressure conditions to remove impurities (Hydrofining, Xiangfang Chen et al., China Petrochemical Press, page 26, 2006); while the latter uses a reduced catalyst (pure metal) under low temperature and low pressure conditions to saturate unsaturated C=O through hydrogenation, rather than removing the O element. The technical solution of the present invention is mainly for the hydrogenation process of aldehydes and ketones.

[0003] The hydrogenation of butyraldehyde to produce butanol and the hydrogenation of acetone to produce isopropanol are typical hydrogenation reaction processes. Both n-butanol and isopropanol are important chemical raw materials. n-Butanol can be used to produce plasticizers, solvents, dehydrating agents, extractants, etc., while isopropanol is widely used in many fields such as medicine, coatings, inks, fragrances, and the electronics industry, especially in the electronics industry, where it has great development potential.

[0004] At present, the mainstream process for producing n-butanol is to hydroformylate propylene and synthesis gas to obtain butyraldehyde, and then obtain n-butanol by gas-phase hydrogenation of butyraldehyde. The main processes for producing isopropanol are acetone gas-phase hydrogenation, propylene hydration and isopropyl acetate hydrogenation. Due to the decline in acetone costs, acetone gas-phase hydrogenation has become the current mainstream process.

[0005] According to the different phases of the raw materials, the hydrogenation process can be divided into two methods: gas phase hydrogenation and liquid phase hydrogenation. Gas phase hydrogenation has the advantages of mild reaction conditions and simple operating conditions, but the materials need to be completely vaporized, and the energy consumption is very high. Liquid phase hydrogenation has the advantages of low reaction temperature, low energy consumption, large production capacity, and high product quality. Among them, the domestic industrial technology of gas phase hydrogenation is relatively mature, while there are few reports on related research on liquid phase hydrogenation.

[0006] Since hydrogenation reactions are all highly exothermic reactions, isothermal tubular reactors (CN113559794A) or adiabatic bed reactors are generally used. Isothermal tubular reactors require a cooling liquid circulation system, and there are the disadvantages of complex systems and high investment. The core point of adiabatic bed reactors is how to remove heat, thereby reducing adiabatic temperature rise, reducing side reaction selectivity, and improving product yield and quality. For liquid phase hydrogenation reactions, adiabatic bed reactors generally use hydrogen circulation or product circulation to remove heat. Traditional processes use a large amount of hydrogen circulation cooling to remove reaction heat, and it is necessary to set a circulating hydrogen compressor, which increases investment, increases power consumption, and has complex process operations. The most preferred heat removal scheme is to use liquid phase product circulation cooling, and the existing liquid phase hydrogenation process is inflexible, and the operating temperature is non-segmentally controlled, and the product is directly circulated to the feed section. The circulated product is all used to dilute the feed, and in order to control the adiabatic temperature rise, the product circulation amount is large, and the energy consumption is high.

[0007] Sinopec has proposed a method for producing butanol by liquid-phase hydrogenation of butyraldehyde (CN104557456A), wherein the specific process is as follows: the reaction device is a series-connected first-stage hydrogenation reactor (1) and a second-stage hydrogenation reactor (2), the process conditions in the two reactors are controlled separately, and the degree of reaction required and the reaction conversion rate are controlled separately; wherein the butyraldehyde conversion rate of the first-stage hydrogenation reactor (1) is 80% to 95%, and the reaction selectivity of producing butanol is 99% to 99.8%; the butyraldehyde conversion rate of the second-stage hydrogenation reactor (2) is 60% to 95%, and the reaction selectivity of producing butanol is 98.5% to 99.7%, the total butyraldehyde conversion rate is 95% to 99.8%, and the total butanol reaction selectivity is 99 to 99.6%. The invention adopts a series-connected fixed-bed reactor to carry out liquid-phase hydrogenation reaction process conditions and control them separately, and the degree of reaction required and the conversion rate are controlled separately, thereby avoiding the condensation and polymerization of butyraldehyde and other side reactions to the greatest extent. The patent adopts a two-stage hydrogenation reactor, which increases the investment and operation difficulty. According to the patent description, the hydrogen at the outlet of the gas-liquid separator needs to be returned to the top inlet of the first-stage hydrogenation reactor, and a circulating hydrogen compressor needs to be installed, which also increases investment and operation difficulty. At the same time, all aldehyde raw materials in the patent are added from the inlet of the first-stage hydrogenation reactor, which increases the adiabatic temperature rise. The patent does not mention the core problem in the liquid phase hydrogenation process: how to remove the reaction heat in the process to avoid the problem of excessive adiabatic temperature rise. Summary of the invention

[0008] In order to solve the problem of large circulation volume or excessive adiabatic temperature rise of existing liquid phase hydrogenation products, the present invention provides a multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones, which adopts liquid phase product circulation to remove reaction heat, and adopts multiple stages of separate cold shock to control adiabatic temperature rise. By independently controlling the flow rate and temperature of each stage of circulating quenching materials, the temperature of each catalyst bed is independently controlled, so that the reactant concentration and operating temperature in each stage of the reactor are maintained within a reasonable range, reducing adiabatic temperature rise, extending catalyst life, reducing the occurrence of side reactions, improving product quality and yield, reducing the circulation volume of liquid phase products, and reducing energy consumption. The hydrogenation effect can be achieved by using a single trickle bed reactor, thereby reducing equipment investment.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones, comprising a multi-stage cold shock liquid phase hydrogenation reactor 5, wherein the multi-stage cold shock liquid phase hydrogenation reactor 5 is a trickle bed reactor, wherein a hydrogenation raw material inlet is provided at the top, a hydrogenation product outlet and a hydrogenation purge gas outlet are provided at the bottom, and the multi-stage cold shock liquid phase hydrogenation reactor 5 is filled with a multi-stage catalyst bed (≥2 layers) inside, and a product circulating liquid inlet is provided above each stage of the catalyst bed, for introducing the product circulating liquid into the corresponding catalyst bed and then regulating the bed temperature, and controlling the adiabatic temperature rise of the reactor; preferably, a liquid collection and redistributor (not shown) is provided above each stage of the catalyst bed. For the convenience of distinguishing different catalyst beds, in the present invention, each catalyst bed is sequentially recorded from top to bottom as a first stage catalyst bed A, a second stage catalyst bed B, a third stage catalyst bed C, a fourth stage catalyst bed D...

[0011] The hydrogenation raw material inlet is connected to a feed main pipe, on which a mixer 4 is provided; the inlet end of the feed main pipe is connected to a hydrogen pipe for inputting hydrogen 102 into the mixer 4, and is also connected to a section of feed pipe for inputting a section of feed 103 into the mixer 4; a start-up preheater 3 is provided on the section of feed pipe for heating a section of feed 103 to a desired temperature during the start-up phase of the equipment.

[0012] The inlet ends of the feed pipe sections are respectively connected to the raw material pipe for inputting the raw material 101 into the feed pipe sections, and are also connected to a quench pipe section for inputting a circulating quench liquid 106 into the feed pipe sections.

[0013] The raw material pipe is provided with a raw material tank 1 and a raw material pump 2 in sequence along the liquid flow direction, for caching and conveying liquid raw materials.

[0014] A buffer space is provided at the bottom of the multi-stage cold shock liquid phase hydrogenation reactor 5, the hydrogenation purge gas outlet is provided at the upper part of the side wall of the buffer space, and the hydrogenation product outlet is located at the bottom of the buffer space; the buffer space is used for preliminary vapor-liquid separation of the mixed material flow running to the bottom of the reactor.

[0015] The hydrogenation product outlet is connected to the circulation main pipe and the discharge pipe respectively, so as to discharge the hydrogenation circulation quenching liquid 105 and the reactor discharge 104 respectively; the circulation main pipe is provided with a circulation pump 6, and the other end thereof is connected in parallel with a plurality of quenching pipes, the number of the quenching pipes connected in parallel is the same as the number of the catalyst bed sections in the reactor 5, and except for one quenching pipe, the other quenching pipes are directly connected to the circulation product inlet on the side wall of the multi-section cold-shock liquid-phase hydrogenation reactor 5, so as to independently supply the circulation quenching liquid to each section of the catalyst bed. Wherein, each quenching pipe is provided with an independent circulation cooler and / or regulating valve, so as to independently control the temperature and / or flow rate of each section of the circulation cooling liquid.

[0016] The discharge pipe is connected to the flash tank 11; the hydrogenation purge gas outlet is connected to the flash tank 11 through a gas phase pipeline; a flash purge gas pipe with a purge gas cooler 13 is provided at the top of the flash tank 11, and a product pipe connected to a product pump 12 is provided at the bottom, so as to discharge the flash purge gas 111 and the hydrogenation product 112 obtained after flash treatment respectively.

[0017] It should be particularly pointed out that the multi-stage catalyst bed of the present invention is a non-equal height bed. Specifically, the height of the upper catalyst bed is less than the height of the lower catalyst bed. The "upper stage height is less than the lower stage" here not only includes the situation where the height increases from top to bottom, but also includes, for example, when there are four or more stages of catalyst beds, if the first and second stages are of equal height, and the third and fourth stages are of equal height, but the heights of the first and second stages are both less than the third and fourth stages, this arrangement also meets the aforementioned "upper stage height is less than the lower stage" limitation. However, it should be noted that this limitation strictly excludes the situation where the height of any upper stage filler is greater than the height of the lower stage filler.

[0018] The catalyst arrangement is important for achieving the technical purpose of the present invention, and is proposed based on the following findings of the inventors: the heating rate of the upper catalyst bed is higher than the heating rate of the lower catalyst bed, and the difference in heating rates is greater in a catalytic reactor ( Figure 1 The catalytic reactor (shown in Figure 2) is more efficient than the catalytic reactor ( Figure 2 shown) is more obvious.

[0019] When the circulating liquid quenching liquid 105 is divided into multiple streams to quench each catalyst bed, it will dilute the components to be hydrogenated in the feed stream, and due to the accumulation of the circulating quenching liquid 105, the dilution effect increases from top to bottom. For example, the liquid feed stream received by the first catalyst bed A is a mixture of the raw material 101 and the first circulating quenching liquid 106. Therefore, the raw material 101 is only diluted by the first circulating quenching liquid 106, and the concentration of the components to be hydrogenated in the feed stream is relatively high; while the liquid feed stream received by the second catalyst bed B includes the downstream feed stream of the first catalyst bed A and the mixture of the second circulating quenching liquid 107. Even if the consumption of the components to be hydrogenated in the raw material 101 by the first catalyst bed A is not taken into account, the components to be hydrogenated in the feed stream corresponding to the second catalyst bed B have also undergone joint dilution by the first circulating quenching liquid 106 and the second circulating quenching liquid 107, so its concentration is lower than the concentration of the components to be hydrogenated corresponding to the first catalyst bed A. Similarly, it can be seen that the concentration of the component to be hydrogenated in the material flow corresponding to the lower position of the catalyst bed is lower.

[0020] The concentration of the component to be hydrogenated in the corresponding stream of each section of the catalyst bed determines the reaction intensity of the section of the bed, which directly determines the adiabatic temperature rise of the section of the bed. Specifically, according to the analysis in the previous article, if the catalyst beds are set at the same height, the higher the position of the catalyst bed, the greater the adiabatic temperature rise. The possible result is that the adiabatic temperature rise of the raw material inlet and the product outlet of the reactor 5 is distorted, so that the temperature rise of each catalyst bed cannot be truly reflected. For example, when the adiabatic temperature rise of a section of catalyst bed A has exceeded the allowable range, since each section of the catalyst bed will introduce the corresponding circulating quenching liquid, the overall adiabatic temperature rise monitored by the inlet and outlet of the reactor 5 can still be within the normal range.

[0021] The inventors have tried to solve the problem of excessive adiabatic temperature rise caused by greater reaction intensity of the upper catalyst bed by increasing the flow rate of the circulating quenching liquid corresponding to the upper catalyst bed or further reducing the temperature of the circulating quenching liquid, but the results were not ideal. The specific reasons are as follows:

[0022] When each section of the catalyst bed is set at the same height, taking a section of the catalyst bed A as an example, increasing the flow rate of a section of the circulating quenching liquid 106 or further reducing the temperature of a section of the circulating quenching liquid 106 can ensure that the temperature at the bottom of a section of the catalyst bed A does not exceed the standard, but an excessively large quenching liquid flow rate or an excessively low quenching liquid temperature will cause the temperature at the top of the section of the catalyst bed A to be too low, thereby reducing the catalytic efficiency or catalytic selectivity at the top. In other words, this solution cannot effectively reduce the temperature rise of a section of the catalyst bed A.

[0023] The above-mentioned catalyst arrangement scheme of "the height of the upper section is smaller than that of the lower section" of the present invention can effectively reduce the temperature rise of the upper section catalyst bed, so that the local adiabatic temperature rise of each section catalyst bed can also meet the standard while ensuring that the overall adiabatic temperature rise of the reactor 5 meets the standard. This is important for the selectivity and catalytic efficiency of the catalytic reaction, and can effectively reduce the amount of by-products generated and improve product purity.

[0024] The reactor 5 is of trickle bed type. The reactor 5 is filled with hydrogen. The hydrogenated materials flow through the catalyst bed in a droplet shape. The hydrogen concentration in the reactor is controlled by controlling the flow rate of the hydrogenation purge gas.

[0025] Preferably, the multi-stage cold shock liquid phase hydrogenation reactor 5 is filled with a multi-stage catalyst bed having a number of layers of ≥2 layers, and more preferably having a number of layers of ≥4 layers.

[0026] The liquid phase hydrogenation catalyst used is a supported nickel catalyst, preferably a supported catalyst with a high nickel content and an activity higher than that of Raney nickel, and more preferably a supported nickel catalyst with a nickel content of ≥50 wt%.

[0027] The present invention also provides a hydrogenation method, which uses a single multi-stage cold shock trickle bed liquid phase hydrogenation reactor to achieve the purpose of hydrogenation, and specifically comprises the following steps:

[0028] (1) The raw material 101 first enters the raw material tank 1 for buffering, and then is pressurized by the raw material pump 2 and mixed with a first-stage circulating cold shock liquid 106 and sent to the start-up preheater 3 (only used in the start-up stage). After being preheated to the reaction temperature, it is mixed with hydrogen 102 in the mixer 4 and enters the multi-stage cold shock liquid phase hydrogenation reactor 5.

[0029] (2) The multi-stage cold shock liquid phase hydrogenation reactor 5 is filled with multiple catalyst beds (≥2 layers), and product circulating liquid is used for quenching between each stage to reduce the adiabatic temperature rise of the reactor, thereby reducing the reactor outlet temperature. A liquid collector and redistributor is provided between each catalyst bed. By controlling the flow rate and temperature of the circulating cold shock liquid of each catalyst bed, the feed concentration and temperature of each catalyst bed can be controlled, thereby flexibly controlling the adiabatic temperature rise of the reactor bed. Through the multi-stage hydrogenation reaction, the materials to be hydrogenated in the hydrogenation feedstock are basically hydrogenated completely. The purge gas 110 of the hydrogenation reactor is sent to the flash tank 11 for separation and recovery of the organic matter therein.

[0030] (3) The liquid phase product of the multi-stage cold-shock liquid phase hydrogenation reactor 5 is divided into two streams: one part is sent to the flash tank 11 as the reactor discharge 104, and the other part is circulated as the hydrogenation circulating quenching liquid 105 to dilute the raw material concentration. The hydrogenation circulating quenching liquid 105 is first pressurized by the circulation pump 6, and then divided into multiple streams and sent to each stage of the circulating cooler to cool to different temperatures, and then sent to the inlet of each stage of the catalyst bed as the circulating quenching liquid. One stage of the circulating quenching liquid 106 is used as a solvent to dilute the raw material 101.

[0031] (4) In the flash tank 11, low-pressure flash evaporation is used to separate the purge gas and the hydrogenation product. The resulting flash purge gas 111 is sent to the outside after the organic matter is recovered through the purge gas cooler 13, and the hydrogenation product 112 is pressurized by the product pump 12 and sent to the outside.

[0032] The operating conditions of the multi-stage cold shock liquid phase hydrogenation reactor 5 are 60-180° C. and 0.5-6.0 MPaG, preferably 60-120° C. and 1.0-4.0 MPaG.

[0033] The circulation ratio of the multi-stage quenched liquid phase hydrogenation reactor 5 (ratio of hydrogenation circulation quenching liquid 105 to raw material 101) is 2 to 30:1, more preferably 5 to 20:1.

[0034] The hydrogen-to-agent ratio (molar ratio of hydrogen 102 to raw material 101) of the multi-stage cold shock liquid phase hydrogenation reactor is relatively low, preferably 1 to 1.5:1, and more preferably 1 to 1.2:1.

[0035] Compared with the prior art, the main points of the present invention are:

[0036] (1) A trickle bed liquid phase hydrogenation reactor is used, and the liquid phase product is circulated to remove the reaction heat. No hydrogen circulation compressor is required, which reduces investment, power consumption and operation difficulty;

[0037] (2) The use of a multi-stage cold shock reactor can independently control the flow rate and temperature of the circulating quenching material in each stage, thereby independently controlling the temperature of each catalyst bed, so that the reactant concentration and operating temperature in each stage of the reactor are maintained within a reasonable range, reducing the adiabatic temperature rise, extending the catalyst life, reducing the occurrence of side reactions, improving product quality and yield, reducing the circulation volume of liquid products, and reducing energy consumption. A single trickle bed reactor can achieve a good hydrogenation effect, thereby reducing equipment investment.

[0038] (3) The multi-stage catalyst bed is loaded in a manner of gradually increasing height from top to bottom, ensuring that the local adiabatic temperature rise of each stage of the catalyst bed meets the reaction requirements.

[0039] The purpose of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but the accompanying drawings and embodiments do not constitute a limitation to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The schematic diagram of a multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones.

[0041] Figure 2 This is a schematic diagram of a single-stage feed cold-shocked trickle bed reaction system for liquid-phase hydrogenation of aldehydes and ketones.

[0042] Equipment in the figure: 1 is a raw material tank, 2 is a raw material pump, 3 is a start-up preheater, 4 is a mixer, 5 is a multi-stage cold shock liquid phase hydrogenation reactor, 6 is a circulation pump, 7 is a first-stage circulation cooler, 8 is a second-stage circulation cooler, 9 is a third-stage circulation cooler, 10 is a fourth-stage circulation cooler, 11 is a flash tank, 12 is a product pump, and 13 is a purge gas cooler.

[0043] Pipelines in the figure: 101 is raw material, 102 is hydrogen, 103 is first-stage feed, 104 is reactor discharge, 105 is hydrogenation circulating quenching liquid, 106 is first-stage circulating quenching liquid, 107 is second-stage circulating quenching liquid, 108 is third-stage circulating quenching liquid, 109 is fourth-stage circulating quenching liquid, 110 is hydrogenation reactor purge gas, 111 is hydrogenation purge gas, and 112 is hydrogenation product.

[0044] Simplified codes in the figure: LS is low-pressure steam, CWS is circulating cooling water, and CHWS is low-temperature water.

[0045] A, B, C, and D are the four catalyst beds from top to bottom in the multi-stage cold shock liquid phase hydrogenation reactor. Specific implementation plan

[0046] Example 1

[0047] like Figure 1 A multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones of the present invention is used for liquid phase hydrogenation of butyraldehyde to prepare butanol, with a raw material processing capacity of 12.5 t / h butyraldehyde and a butanol product scale of 100,000 tons / year.

[0048] (1) Butyraldehyde raw material 101 first enters raw material tank 1 for buffering, then is pressurized by raw material pump 2, mixed with a first-stage circulating cold shock liquid 106, and then sent to start-up preheater 3. After being preheated to the reaction temperature, it is mixed with hydrogen 102 in mixer 4 and enters multi-stage cold shock liquid phase hydrogenation reactor 5.

[0049] (2) The multi-stage cold shock liquid phase hydrogenation reactor 5 is filled with 4 catalyst beds, and product circulating liquid is used for quenching between the 4 stages to reduce the adiabatic temperature rise of the reactor, thereby reducing the reactor outlet temperature. A liquid collector and redistributor is provided between each bed of the multi-stage cold shock liquid phase hydrogenation reactor 5. The hydrogenation purge gas 110 is sent to the flash tank 11 for separation and recovery of organic matter therein. By controlling the flow rate and temperature of the circulating cold shock liquid between each stage, the feed concentration and temperature of each catalyst bed can be controlled, thereby flexibly controlling the adiabatic temperature rise of the reactor bed. Through the multi-stage hydrogenation reaction, the materials to be hydrogenated in the hydrogenation feedstock are basically hydrogenated completely.

[0050] (3) The liquid phase product of the multi-stage cold-shock liquid phase hydrogenation reactor is divided into two streams: one part is sent to the flash tank 11 as the reactor discharge 104, and the other part is circulated as the hydrogenation circulating quenching liquid 105 to dilute the raw material concentration. The hydrogenation circulating quenching liquid 105 is first pressurized by the circulating pump 6, and then divided into multiple streams and sent to each stage of the circulating cooler 7-10 to cool to different temperatures, and then sent to the inlet of each stage of the catalyst bed as the circulating quenching liquid. The first stage of the circulating quenching liquid 106 is used as a solvent to dilute the raw material.

[0051] (4) In the flash tank 11, low-pressure flash evaporation is used to separate the flash purge gas 111 and the hydrogenation product 112. The flash purge gas 111 is sent to the outside after the organic matter therein is recovered through the purge gas cooler 13, and the hydrogenation product 112 is pressurized through the product pump 12 and sent to the outside.

[0052] The operating conditions of the raw material tank 1 are 0.2 MPaG and 40°C; the operating pressure of the multi-stage cold shock liquid phase hydrogenation reactor 5 is 1.5 MPaG, the feed temperature is 65°C, and the outlet temperature of each catalyst bed needs to be controlled to be ≤120°C.

[0053] The total circulation ratio of the reaction system (the flow ratio of the hydrogenation cycle quenching liquid 105 to the raw material 101) is 6:1, the hydrogen agent ratio (the molar ratio of hydrogen to raw material) of the multi-stage quenching liquid phase hydrogenation reactor is 1.05:1, and the hydrogen flow rate is 4077Nm 3 / h.

[0054] The flow rate of hydrogenation circulating quenching liquid 105 is 62.5t / h, and the flow rates of the first to fourth circulating quenching liquids are 25t / h, 15t / h, 13t / h and 9.5t / h respectively, which are cooled to 78°C, 40°C, 40°C and 40°C respectively through circulating coolers 7 to 10.

[0055] The catalyst in the four catalyst beds inside the multi-stage cold shock liquid phase hydrogenation reactor uses a loaded nickel catalyst with a nickel content of 55wt%. The bed heights of the four catalyst beds A / B / C / D of the multi-stage cold shock liquid phase hydrogenation reactor are changed to 5m, 6m, 7m, and 8m respectively.

[0056] The inlet and outlet temperatures and adiabatic temperature rise of each catalyst bed are as follows:

[0057] The inlet temperature of the first stage catalyst bed is about 65°C, the adiabatic temperature rise is about 50°C, and the outlet temperature is 115°C;

[0058] The feed temperature of the catalyst bed in the second stage is about 96°C, the adiabatic temperature rise is about 19°C, and the outlet temperature is 115°C;

[0059] The feed temperature of the catalyst bed in the third stage is about 102°C, the adiabatic temperature rise is about 13°C, and the outlet temperature is 115°C;

[0060] The feed temperature of the fourth stage catalyst bed is about 107°C, the adiabatic temperature rise is about 8°C, and the outlet temperature is 115°C.

[0061] The outlet temperature of each catalyst bed is ≤115℃.

[0062] After the hydrogenation product is simply separated in the gas-liquid separation space at the bottom of the reactor, the hydrogenation reactor purge gas 110 all enters the flash tank 11, the reactor discharge 104 is taken out to the flash tank 11, and the hydrogenation circulating quenching liquid 105 is used as the circulating liquid and then sent to each catalyst bed according to proportion.

[0063] The operating conditions of the flash tank 11 are 111°C and 0.2MPaG. The flow rate of the bottom liquid hydrogenation product of the flash tank 11 is 12.85t / h. The hydrogenation purge gas 111 is cooled to 20°C by the purge gas cooler 13. The liquid phase returns to the flash tank 11. The flow rate of the cooled hydrogenation purge gas is 202Nm 3 / h.

[0064] After being treated by a multi-stage cold-shock liquid phase hydrogenation reactor, the total conversion rate of butyraldehyde and the selectivity of butanol are both ≥99.5%.

[0065] Example 2

[0066] like Figure 1 The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones of the present invention is used for liquid phase hydrogenation of acetone to prepare isopropanol, with a raw material processing capacity of 12.5 t / h acetone and an isopropanol product scale of 100,000 tons / year.

[0067] Compared with Example 1, the process flow and equipment used in this example are the same, and the differences are as follows:

[0068] The total circulation ratio of the reaction system (the flow ratio of the hydrogenation cycle quenching liquid 105 to the raw material 101) is 6:1, the hydrogen agent ratio (the molar ratio of hydrogen to raw material) of the multi-stage quenching liquid phase hydrogenation reactor is 1.05:1, and the hydrogen flow rate is 5062.4Nm 3 / h.

[0069] The flow rate of hydrogenation circulating quenching liquid 105 is 62.5t / h, and the flow rates of the first to fourth circulating quenching liquids are 25t / h, 15t / h, 13t / h and 9.5t / h respectively, which are cooled to 82°C, 45°C, 45°C and 45°C respectively through circulating coolers 7 to 10.

[0070] The catalysts in the four catalyst beds inside the multi-stage cold shock liquid phase hydrogenation reactor use loaded nickel catalysts with a nickel content of 55 wt%. The bed heights of the four catalyst beds A / B / C / D of the multi-stage cold shock liquid phase hydrogenation reactor are 5m, 6m, 7m, and 8m, respectively.

[0071] The inlet and outlet temperatures and adiabatic temperature rise of each catalyst bed are as follows:

[0072] The inlet temperature of the first stage catalyst bed is about 65°C, the adiabatic temperature rise is about 42°C, and the outlet temperature is 107°C;

[0073] The feed temperature of the catalyst bed in the second stage is about 93°C, the adiabatic temperature rise is about 17°C, and the outlet temperature is 110°C;

[0074] The feed temperature of the catalyst bed in the third stage is about 100°C, the adiabatic temperature rise is about 12°C, and the outlet temperature is 112°C;

[0075] The feed temperature of the catalyst bed in the fourth stage is about 105°C, the adiabatic temperature rise is about 8°C, and the outlet temperature is 113°C;

[0076] The outlet temperature of each catalyst bed is ≤115℃.

[0077] The operating conditions of the flash tank 11 are 97°C and 0.2MPaG. The flow rate of the bottom liquid hydrogenation product of the flash tank 11 is 12.93t / h. The hydrogenation purge gas 111 is cooled to 10°C by the purge gas cooler 13. The liquid phase returns to the flash tank 11. The flow rate of the cooled hydrogenation purge gas is 255Nm 3 / h.

[0078] After being treated by a multi-stage cold-shock liquid phase hydrogenation reactor, the total conversion rate of acetone and the selectivity of isopropanol are both ≥99.5%.

[0079] Example 3

[0080] like Figure 1 Compared with Example 1, the heights of the four catalyst beds A / B / C / D of the multi-stage cold shock liquid phase hydrogenation reactor are changed to 5m, 6m, 7.5m, and 7.5m, respectively.

[0081] The flow rate of the hydrogenation circulating quenching liquid 105 is 62.5t / h, and the flow rates of the first to fourth circulating quenching liquids are 25t / h, 15t / h, 13t / h, and 9.5t / h, respectively. They are cooled to 78°C, 40°C, 40°C, and 40°C through circulating coolers 7 to 10, respectively, which is the same as Example 1.

[0082] The inlet and outlet temperatures and adiabatic temperature rise of each catalyst bed are as follows:

[0083] The inlet temperature of the first stage catalyst bed is about 65°C, the adiabatic temperature rise is about 50°C, and the outlet temperature is 115°C;

[0084] The feed temperature of the catalyst bed in the second stage is about 96°C, the adiabatic temperature rise is about 19°C, and the outlet temperature is 115°C;

[0085] The feed temperature of the catalyst bed in the third stage is about 102°C, the adiabatic temperature rise is about 15°C, and the outlet temperature is 117°C;

[0086] The feed temperature of the catalyst bed in the fourth stage is about 108°C, the adiabatic temperature rise is about 7°C, and the outlet temperature is 115°C.

[0087] The outlet temperature of each catalyst bed layer is ≤117°C, meeting the requirement that the outlet temperature of each catalyst bed layer is ≤120°C.

[0088] Example 4

[0089] like Figure 1 Compared with Example 1, the bed heights of the four catalyst beds A / B / C / D of the multi-stage cold shock liquid phase hydrogenation reactor are all 6.5 m.

[0090] The flow rate of the hydrogenation circulating quenching liquid 105 is 62.5t / h, and the flow rates of the first to fourth circulating quenching liquids are 25t / h, 15t / h, 13t / h, and 9.5t / h, respectively. They are cooled to 78°C, 40°C, 40°C, and 40°C through circulating coolers 7 to 10, respectively, which is the same as Example 1.

[0091] The inlet and outlet temperatures and adiabatic temperature rise of each catalyst bed are as follows:

[0092] The inlet temperature of the first stage catalyst bed is about 65°C, the adiabatic temperature rise is about 55°C, and the outlet temperature is 120°C;

[0093] The feed temperature of the catalyst bed in the second stage is about 99°C, the adiabatic temperature rise is about 20°C, and the outlet temperature is 119°C;

[0094] The feed temperature of the catalyst bed in the third stage is about 105°C, the adiabatic temperature rise is about 11°C, and the outlet temperature is 116°C;

[0095] The feed temperature of the fourth stage catalyst bed is about 107°C, the adiabatic temperature rise is about 8°C, and the outlet temperature is 115°C.

[0096] Compared with Example 1, the first and second catalyst beds have a greater reaction intensity and a more violent reaction. Although the overall adiabatic temperature rise is the same as in Example 1, with the reactor inlet to outlet increasing from 65°C to 115°C, the outlet temperature of the first and second catalyst beds is slightly higher, reaching 120°C, which will increase side reactions and slightly reduce the butanol yield.

[0097] Comparative Example 1

[0098] like Figure 2 Compared with Example 1, a one-stage feed quenching technical solution is adopted, and the inter-stage quenching is eliminated. It is used for liquid-phase hydrogenation of butyraldehyde to prepare butanol. The raw material processing capacity is 12.5t / h butyraldehyde, and the butanol product scale is 100,000 tons / year.

[0099] After calculation, when the reactor inlet temperature is 65°C, in order to control the reactor outlet temperature at 115°C, the hydrogenation circulating quenching liquid is 80 t / h, which is 17.5 t / h higher than the flow rate in Example 1, and the increase ratio is 28%. With the increase of hydrogenation circulating quenching liquid, the energy consumption and investment of the system will increase.

[0100] Comparative Example 2

[0101] like Figure 2 Compared with Example 1, a one-stage feed quenching technical solution is adopted, and the inter-stage quenching is eliminated. It is used for liquid-phase hydrogenation of butyraldehyde to prepare butanol. The raw material processing capacity is 12.5t / h butyraldehyde, and the butanol product scale is 100,000 tons / year.

[0102] After calculation, when the flow rate of hydrogenation cycle quenching liquid is the same as that in Example 1, that is, the flow rate is 62.5 t / h, the reactor inlet temperature is 65°C, and the reactor outlet temperature is 125°C, which is 10°C higher than the outlet temperature in Example 1. This will reduce the overall selectivity of butanol.

Claims

1. A multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones, characterized in that: The invention comprises a multi-stage cold shock liquid phase hydrogenation reactor (5), wherein a hydrogenation raw material inlet is provided at the top, a hydrogenation product outlet and a hydrogenation purge gas outlet are provided at the bottom, and at least two catalyst beds are filled inside, and a product circulating liquid inlet is provided above each catalyst bed for introducing product circulating liquid into the corresponding catalyst bed; the hydrogenation raw material inlet is connected to a feed main pipe, and a mixer (4) is provided on the feed main pipe; the inlet end of the feed main pipe is connected to a hydrogen pipe for inputting hydrogen (102) into the mixer (4), and is also connected to a feed pipe for inputting a feed (103) into the mixer (4); the inlet ends of the feed pipes are respectively connected to raw material pipes for inputting raw materials (101) into the feed pipes, A section of cold shock pipe is also connected to input a section of circulating quenching liquid (106) into a section of feeding pipe; a buffer space is provided at the bottom of the multi-section cold shock liquid phase hydrogenation reactor (5), a hydrogenation purge gas outlet is provided at the upper part of the side wall of the buffer space, and a hydrogenation product outlet is located at the bottom of the buffer space; the hydrogenation product outlet is respectively connected to the circulation main pipe and the discharge pipe to discharge the hydrogenation circulating quenching liquid (105) and the reactor discharge (104) respectively; the discharge pipe is connected to the flash tank (11); the hydrogenation purge gas outlet is connected to the flash tank (11) through a gas phase pipeline; a flash purge gas pipe with a purge gas cooler (13) is provided at the top of the flash tank (11), and a product pipe connected to a product pump (12) is provided at the bottom.

2. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 1, characterized in that: The circulation main pipe is provided with a circulation pump (6), and the other end of the circulation main pipe is connected in parallel with a plurality of quenching tubes, the number of the quenching tubes connected in parallel is the same as the number of the catalyst bed sections in the reactor (5), and except for one quenching tube, the other quenching tubes are directly connected to the circulation product inlet on the side wall of the multi-section cold-shock liquid phase hydrogenation reactor (5), and each quenching tube is provided with an independent circulation cooler and / or regulating valve for independently controlling the temperature and / or flow rate of each section of the circulation coolant.

3. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 2, characterized in that: A liquid collector and redistributor is provided above each catalyst bed; a start-up preheater (3) is provided on the feed pipe for heating a feed (103) during the equipment startup phase.

4. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 3, characterized in that: A raw material tank (1) and a raw material pump (2) are arranged in sequence on the raw material pipe along the liquid flow direction.

5. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 4, characterized in that: The multi-stage cold shock liquid phase hydrogenation reactor (5) is a trickle bed reactor and is filled with hydrogen. The hydrogenation material flows through the catalyst bed in a droplet shape. The hydrogen concentration in the reactor is controlled by controlling the flow rate of the hydrogenation purge gas.

6. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 5, characterized in that: The number of catalyst layers in the multi-stage cold shock liquid phase hydrogenation reactor (5) is ≥4 layers; and the liquid phase hydrogenation catalyst used is a loaded nickel catalyst with a nickel content of ≥50wt%.

7. The multi-stage cold shock trickle bed reaction system for liquid phase hydrogenation of aldehydes and ketones according to claim 6, characterized in that: The at least two catalyst beds are non-uniformly oriented beds, and the height of the upper catalyst bed is smaller than the height of the lower catalyst bed.

8. A method for liquid phase hydrogenation of aldehydes and ketones based on the multi-stage cold shock trickle bed reaction system according to any one of claims 1 to 7, wherein a single multi-stage cold shock trickle bed liquid phase hydrogenation reactor (5) is used to achieve the purpose of hydrogenation, and specifically comprises the following steps: (1) The raw material (101) first enters the raw material tank (1) for buffering, is then pressurized by the raw material pump (2), mixed with a first-stage circulating cold shock liquid (106), and then sent to the start-up preheater (3) for preheating to the reaction temperature, and then mixed with hydrogen (102) in the mixer (4) and enters the multi-stage cold shock liquid phase hydrogenation reactor (5); (2) A multi-stage cold shock liquid phase hydrogenation reactor (5) is filled with multiple catalyst beds, and product circulating liquid is used for quenching between each stage to reduce the adiabatic temperature rise of the reactor, thereby reducing the reactor outlet temperature; the adiabatic temperature rise of the reactor bed is independently controlled by controlling the flow rate and temperature of the circulating cold shock liquid of each catalyst bed; the hydrogenation purge gas (110) is sent to a flash tank (11) for separation, and the organic matter therein is recovered; (3) The liquid phase product of the multi-stage cold-shock liquid phase hydrogenation reactor (5) is divided into two streams: one part is sent to the flash tank (11) as the reactor discharge (104), and the other part is circulated as the hydrogenation circulating quenching liquid (105) to dilute the raw material concentration; the hydrogenation circulating quenching liquid (105) is first pressurized by a circulation pump (6), and then divided into multiple streams and sent to each stage of the circulating cooler to be cooled to different temperatures, and then sent to the inlet of each stage of the catalyst bed as the circulating quenching liquid, and one stage of the circulating quenching liquid (106) is used as a solvent to dilute the raw material (101); (4) In the flash tank (11), low-pressure flash evaporation is used to separate the purge gas and the hydrogenation product. The resulting flash purge gas (111) is sent to the outside after the organic matter therein is recovered through the purge gas cooler (13). The hydrogenation product (112) is pressurized by the product pump (12) and sent to the outside.

9. The method for liquid phase hydrogenation of aldehydes and ketones as claimed in claim 8, characterized in that: The operating conditions of the multi-stage cold shock liquid phase hydrogenation reactor (5) are 60-180°C and 0.5-6.0 MPaG, preferably 60-120°C and 1.0-4.0 MPaG.

10. The method for liquid phase hydrogenation of aldehydes and ketones according to claim 9, characterized in that: The circulation ratio of the multi-stage cold shock liquid phase hydrogenation reactor (5) is 2 to 30:1, preferably 5 to 20:1; the hydrogen agent ratio of the multi-stage cold shock liquid phase hydrogenation reactor (5) is 1 to 1.5:1, preferably 1 to 1.2:1.

Images