Method for co-producing butanol, octanol and neopentyl glycol

Abstract

The invention relates to the technical field of petrochemical engineering, and particularly discloses a method for co-producing butanol, octanol and neopentyl glycol, which comprises the following steps: synthesizing butyraldehyde from propylene and synthesis gas through two tower reactors under the action of a catalyst, evaporating butyraldehyde, the mixed catalyst and a ligand through a falling film evaporator, and feeding into a membrane separator; according to the method, butyraldehyde is separated from a catalyst and unreacted products in a membrane separator, butyraldehyde obtained through separation enters an n-butyraldehyde and isobutyraldehyde separation tower, isobutyraldehyde is obtained at the tower top, n-butyraldehyde is obtained at the tower kettle, methanol and air generate formaldehyde under the action of an electrolytic silver catalyst, and a 37% formaldehyde solution is obtained through two absorption towers; according to the invention, butanol, isooctanol and neopentyl glycol are integrated through equipment, and the integrated butyraldehyde reaction device, the integrated condensation reaction device and the integrated hydrogenation reaction device are adopted, so that reaction, heat removal and product separation are realized in one reactor, and the effects of saving energy, reducing consumption and saving land are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and particularly relates to a method for co-producing butanol, octanol and neopentyl glycol. Background Art

[0002] Butanol, isooctyl alcohol, and neopentyl glycol are important organic chemical raw materials. Butanol can be used as a solvent to produce plasticizers such as dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP), as well as chemicals such as butyl acetate and butyl methacrylate. Isooctyl alcohol is primarily used to produce plasticizers such as dioctyl phthalate (DOP) and dioctyl adipate (DOA), as well as octyl acrylate (2-ethylhexyl acrylate), surfactants, and others. DOP is primarily used as a plasticizer in PVC. Isooctyl acrylate produced from isooctyl alcohol can be used in adhesives and surface coatings. Other uses for octanol include nitrates, petroleum additives, surfactants, and solvents. Neopentyl glycol is primarily used as a plasticizer in the production of unsaturated polyester resins, oil-free alkyd resins, polyurethane foams and elastomers, as an additive for high-grade lubricants, and other fine chemicals. Neopentyl glycol is also an excellent solvent for the selective separation of aromatics and cycloalkyl hydrocarbons.

[0003] Currently, the production of butanol, octanol, and neopentyl glycol on the market often requires two sets of equipment for separate production. For example, in the prior art, publication number CN113058517A discloses a micro-interface preparation device and method for butanol and octanol. This method can only produce butanol and isooctyl alcohol, and cannot simultaneously produce butanol, isooctyl alcohol, and neopentyl glycol.

[0004] For example, in the prior art, publication number CN101657397B discloses a method for producing hydroxypivalaldehyde and neopentyl glycol. The effluent from the aldol condensation of isobutyraldehyde and an aqueous formaldehyde solution is separated into an organic phase containing the valuable product and an aqueous phase by adding octanol as an extractant. Subsequently, the organic phase is distilled to remove residual low-boiling substances. The bottoms of the first distillation column are hydrogenated, and after further extraction and distillation, the valuable product, neopentyl glycol, is obtained. This method, which involves condensation, extraction, and hydrogenation, can only produce a single neopentyl glycol, and the process is complex.

[0005] Therefore, we need to propose a method for the co-production of butanol, isooctyl alcohol and neopentyl glycol to solve the above-mentioned problems, so that butanol, isooctyl alcohol and neopentyl glycol can be integrated through equipment, an integrated butyraldehyde reaction unit, an integrated condensation reaction unit and an integrated hydrogenation reaction unit, so as to realize reaction, heat removal and product separation in one reactor, thereby achieving the effect of energy saving, consumption reduction and land saving. Summary of the Invention

[0006] The object of the present invention is to provide a method for co-producing butanol, isooctyl alcohol and neopentyl glycol, which can integrate butanol, isooctyl alcohol and neopentyl glycol through equipment, an integrated butyraldehyde reaction unit, an integrated condensation reaction unit and an integrated hydrogenation reaction unit, so as to realize reaction, heat removal and product separation in one reactor, thereby achieving energy saving, consumption reduction and land saving, and solving the problems raised in the above background technology.

[0007] To achieve the above object, the present invention adopts the following technical solution: a method for co-producing butanol, octanol and neopentyl glycol, comprising the following steps:

[0008] S1. Synthesis gas and propylene are reacted in the main reactor to generate butyraldehyde via the action of catalyst. The circulating cooler controls the reaction heat, and the unreacted materials enter the auxiliary reactor to continue the reaction.

[0009] S2, the discharge from the auxiliary reactor is heated in a falling film evaporator and then enters a membrane separator to separate light components, catalyst and butyraldehyde. The catalyst returns to the main reactor and the mixed butyraldehyde enters a normal-isobutyraldehyde separation tower;

[0010] S3, a normal-isobutyraldehyde separation tower separates isobutyraldehyde and normal-butyraldehyde;

[0011] S4, isobutyraldehyde and formaldehyde generate hydroxypivalaldehyde in a hydroxypivalaldehyde reactor, unreacted components are recovered in a light component recovery tower and returned to the hydroxypivalaldehyde reactor, hydroxypivalaldehyde is hydrogenated in a neopentyl glycol hydrogenation reactor to generate neopentyl glycol, and purified in a neopentyl glycol distillation tower;

[0012] S5, n-butyraldehyde is condensed into octenal in an octenal reactor, which is then gasified in an octenal vaporizer and hydrogenated in an octenal hydrogenation reactor to produce isooctyl alcohol, hydrogen is circulated through an octenal hydrogenation circulation compressor, and the isooctyl alcohol is purified through an isooctyl alcohol distillation tower;

[0013] S6, after the n-butyraldehyde is vaporized in the butyraldehyde vaporizer, it is hydrogenated in the butyraldehyde hydrogenation reactor to produce butanol, the hydrogen is circulated through the butyraldehyde hydrogenation circulation compressor, and the butanol is purified through the butanol distillation tower;

[0014] S7, methanol vapor, air, and steam mixture generate formaldehyde in the formaldehyde reactor, which is absorbed in the formaldehyde absorption tower and then used for subsequent reactions;

[0015] S8, the tail gas is absorbed by the propylene absorption tower and propane, and is analyzed by the propylene analysis tower, and the propylene-propane separation tower separates pure propylene and propane;

[0016] S9. The mixed gas is separated into pure hydrogen and impurity mixed gas through a hydrogen separator.

[0017] Preferably, the main reactor is a two-stage reaction, which reacts with the catalyst to generate butyraldehyde during the reaction. The upper end liquid level is controlled by a butterfly gate flow limiter between the upper and lower sections. The upper section is provided with a porous filler area and a distributor to allow the synthesis gas and propylene to fully contact the catalyst, and a circulating cooler is provided at the bottom of the upper and lower sections to adjust the temperature. The catalyst is set as triphenylphosphine carbonyl acetylacetonate rhodium and the ligand triphenylphosphine. The inlet of the circulating cooler is connected to the main reactor, and the outlet of the circulating cooler is connected to the propylene feed pipeline. The coolant returns to the upper and lower sections of the main reactor to control the reaction heat.

[0018] Preferably, the auxiliary reactor is connected to the circulating cooler via a pipeline, and the pipeline is connected to the propylene pipeline and then enters the auxiliary reactor together. Unreacted propylene and synthesis gas are combined with the discharge from the main reactor and then enter the auxiliary reactor to continue the reaction.

[0019] Preferably, the inlet of the falling film evaporator is connected to the discharge pipeline of the auxiliary reactor, and the outlet of the falling film evaporator is connected to a membrane separator for heating the discharge, and the membrane separator is equipped with a gas-liquid separator and a membrane for gas-liquid separation.

[0020] Preferably, the normal-isobutyraldehyde separation tower is configured as a plate tower, which receives mixed butyraldehyde from a membrane separator to separate normal-isobutyraldehyde, wherein the isobutyraldehyde is extracted from the top of the tower and the normal-butyraldehyde is extracted from the side line of the bottom of the tower.

[0021] Preferably, the hydroxypivalaldehyde reactor uses trimethylamine as a catalyst, and formaldehyde and isobutyraldehyde undergo a condensation reaction to generate hydroxypivalaldehyde, and the hydroxypivalaldehyde reactor is a vertical reactor.

[0022] Preferably, the neopentyl glycol hydrogenation reactor is a vertical fixed-bed reactor, a hydrogenation catalyst is installed in the neopentyl glycol hydrogenation reactor, and multiple neopentyl glycol hydrogenation reactors are connected in series.

[0023] Preferably, the octenal hydrogenation cycle compressor is configured as a centrifugal compressor, the octenal hydrogenation cycle compressor inlet is connected to the octenal hydrogenation reactor, the octenal hydrogenation cycle compressor outlet is connected to the octenal vaporizer, and the consumed hydrogen is replenished at the octenal hydrogenation cycle compressor outlet, and the isooctanol distillation tower is configured as two in series.

[0024] Preferably, the formaldehyde reactor is equipped with a silver catalyst, and the methanol vapor, air, and steam mixture are connected to the formaldehyde reactor through a pipeline, and formaldehyde is generated under the action of the silver catalyst.

[0025] Preferably, the formaldehyde absorption tower is configured as two packed towers connected in parallel, and a desalted water feeding pipeline is provided at the top of the formaldehyde absorption tower. After formaldehyde is absorbed by the desalted water, a 37% formaldehyde aqueous solution is formed and enters the hydroxypivalaldehyde reactor through the pipeline for use.

[0026] The method for co-producing butanol, octanol and neopentyl glycol proposed in the present invention has the following advantages over the prior art:

[0027] 1. The present invention uses propylene, synthesis gas, hydrogen, methanol, and air as raw materials, and synthesizes butyraldehyde from propylene and synthesis gas in the presence of a catalyst through two tower reactors. The butyraldehyde, mixed with the catalyst and ligand, is evaporated in a falling film evaporator and then enters a membrane separator. The butyraldehyde is separated from the catalyst and unreacted products in the membrane separator. The separated butyraldehyde enters a normal-isobutyraldehyde separation tower, isobutyraldehyde is obtained at the top of the tower, and normal-butyraldehyde is obtained in the bottom of the tower. Methanol and air generate formaldehyde under the action of an electrolytic silver catalyst, and 37% formaldehyde is obtained through two absorption towers. Aldehyde solution, formaldehyde solution and isobutyraldehyde are reacted in a hydroxypivalaldehyde reactor to generate hydroxypivalaldehyde, which is then hydrogenated in a neopentyl glycol hydrogenation reactor to generate neopentyl glycol. Impurities in the neopentyl glycol are removed from the neopentyl glycol through a neopentyl glycol distillation tower to obtain a qualified neopentyl glycol product. Butanol, isooctyl alcohol and neopentyl glycol can be integrated into an integrated butyraldehyde reaction unit, an integrated condensation reaction unit and an integrated hydrogenation reaction unit to achieve reaction, heat removal and product separation in one reactor, thereby achieving energy saving, consumption reduction and land saving.

[0028] 2. The present invention adopts a highly integrated device for production, comprehensively utilizes materials in each production link, and centrally recycles waste gas and waste liquid in the production link, which reduces production costs, saves a lot of energy, and has diverse product types, good product quality, strong market adaptability, and high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of the present invention;

[0030] Figure 2 It is a schematic diagram of the principle of the present invention;

[0031] In the figure: 1. main reactor; 2. circulating cooler; 3. auxiliary reactor; 4. falling film evaporator; 5. membrane separator; 6. n-isobutyraldehyde separation tower; 7. hydroxypivalaldehyde reactor; 8. light component recovery tower; 9. neopentyl glycol hydrogenation reactor; 10. neopentyl glycol distillation tower; 11. octenal reactor; 12. octenal vaporizer; 13. octenal hydrogenation reactor; 14. octanol distillation tower; 15. butyraldehyde vaporizer; 16. butyraldehyde hydrogenation reactor; 17. butanol distillation tower; 18. formaldehyde reactor; 19. formaldehyde absorption tower; 20. butyraldehyde hydrogenation circulating compressor; 21. propylene absorption tower; 22. propylene desorption tower; 23. propylene-propane separation tower; 24. hydrogen separator; 25. octenal hydrogenation circulating compressor. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] The present invention provides Figure 1-2 A method for co-producing butanol, octanol and neopentyl glycol is shown, comprising the following steps:

[0035] S1. Synthesis gas and propylene are reacted in the main reactor to generate butyraldehyde via the action of catalyst. The circulating cooler controls the reaction heat, and the unreacted materials enter the auxiliary reactor to continue the reaction.

[0036] S2, the discharge from the auxiliary reactor is heated in a falling film evaporator and then enters a membrane separator to separate light components, catalyst and butyraldehyde. The catalyst returns to the main reactor and the mixed butyraldehyde enters a normal-isobutyraldehyde separation tower;

[0037] S3, a normal-isobutyraldehyde separation tower separates isobutyraldehyde and normal-butyraldehyde;

[0038] S4, isobutyraldehyde and formaldehyde generate hydroxypivalaldehyde in a hydroxypivalaldehyde reactor, unreacted components are recovered in a light component recovery tower and returned to the hydroxypivalaldehyde reactor, hydroxypivalaldehyde is hydrogenated in a neopentyl glycol hydrogenation reactor to generate neopentyl glycol, and purified in a neopentyl glycol distillation tower;

[0039] S5, n-butyraldehyde is condensed into octenal in an octenal reactor, which is then gasified in an octenal vaporizer and hydrogenated in an octenal hydrogenation reactor to produce isooctyl alcohol, hydrogen is circulated through an octenal hydrogenation circulation compressor, and the isooctyl alcohol is purified through an isooctyl alcohol distillation tower;

[0040] S6, after the n-butyraldehyde is vaporized in the butyraldehyde vaporizer, it is hydrogenated in the butyraldehyde hydrogenation reactor to produce butanol, the hydrogen is circulated through the butyraldehyde hydrogenation circulation compressor, and the butanol is purified through the butanol distillation tower;

[0041] S7, methanol vapor, air, and steam mixture generate formaldehyde in the formaldehyde reactor, which is absorbed in the formaldehyde absorption tower and then used for subsequent reactions;

[0042] S8, the tail gas is absorbed by the propylene absorption tower and propane, and is analyzed by the propylene analysis tower, and the propylene-propane separation tower separates pure propylene and propane;

[0043] S9. The mixed gas is separated into pure hydrogen and impurity mixed gas through a hydrogen separator.

[0044] Among them, the main reactor 1 is a two-stage reaction, which reacts with the catalyst to generate butyraldehyde during the reaction. The upper liquid level is controlled by a butterfly gate between the upper and lower sections. The upper section is provided with a porous filler area and a distributor to allow the synthesis gas and propylene to fully contact the catalyst, and a circulating cooler 2 is provided at the bottom of the upper and lower sections to adjust the temperature. The catalyst is set as triphenylphosphine carbonyl acetylacetonate rhodium and ligand triphenylphosphine. The inlet of the circulating cooler 2 is connected to the main reactor 1, and the outlet of the circulating cooler 2 is connected to the propylene feed pipeline. The coolant returns to the upper and lower sections of the main reactor 1 to control the reaction heat. The upper and lower sections are connected by a reduction method. The upper synthesis gas enters the upper reaction part through the upper bottom distributor, and the circulating coolant and propylene enter from the top liquid distributor. The synthesis gas and propylene enter from the top liquid distributor. The reaction occurs under the action of the catalyst. To enhance the contact surface, a porous filler area is provided in the upper section. Under the action of the gas distributor, liquid distributor, and porous filler area, the synthesis gas and propylene are fully contacted to increase the reaction intensity. The butyraldehyde generated by the reaction and the unreacted propylene enter the lower section. The lower section is configured in the same manner as the upper section. To ensure controllable reaction temperature, a circulating cooler 2 is added at the bottom of the first section and the bottom of the second section to adjust the appropriate reaction temperature, solving the problem of uneven distribution and incomplete reaction in the prior art. The combination of the two-stage reactor shortens the process flow, reduces piping work, reduces investment, and improves conversion rate. The top liquid level is controlled in the following manner: the upper section is connected to the synthesis gas pipeline 102, and the lower section is connected to the synthesis gas pipeline 103. The synthesis gas is equipped with a distributor inside the reactor.

[0045] The inlet of the circulating cooler 2 is connected to the main reactor 1 through pipeline 104, and the outlet of the circulating cooler 2 is connected to the propylene feed pipeline 106. The cooling liquid returns to the upper section of the main reactor 1 through pipeline 202 and returns to the lower section of the main reactor 1 through pipeline 201 to control the reaction heat.

[0046] The auxiliary reactor 3 is connected to the circulating cooler 2 through pipeline 203. After pipeline 203 is connected to the propylene pipeline 107, they enter the auxiliary reactor 3 together. The unreacted propylene and synthesis gas are combined with the discharge from the main reactor 1 and then enter the auxiliary reactor 3 to continue the reaction. The synthesis gas pipeline 114 is combined with the propylene and synthesis gas that have not completed the reaction of the main reactor 1 and then enters the auxiliary reactor 3 through pipeline 303 to continue the reaction. 303 is equipped with a distributor inside the auxiliary reactor 3.

[0047] The inlet of the falling film evaporator 4 is connected to the discharge pipeline 301 of the auxiliary reactor 3, and the outlet of the falling film evaporator 4 is connected to the membrane separator 5 through the pipeline 401 for heating the discharge. The membrane separator 5 is equipped with a gas-liquid separator and a membrane for gas-liquid separation. The membrane separator 5 is used to separate light components and catalysts and butyraldehyde. The membrane separator 5 is connected to the top pipeline 302 of the auxiliary reactor 3. The light components at the top of the membrane separator 5 enter the propylene and propane recovery unit, and the bottom discharge is the catalyst returned to the main reactor 1 through the pipeline 502 for continued use. The membrane separator 5 can be one or more units connected in series to achieve the best separation effect.

[0048] The normal-isobutyraldehyde separation tower 6 is configured as a plate tower, and the normal-isobutyraldehyde separation tower 6 receives mixed butyraldehyde from the membrane separator to achieve separation of normal-isobutyraldehyde. Isobutyraldehyde is extracted through the top of the tower, and normal-butyraldehyde is extracted through the side line of the tower bottom. The normal-isobutyraldehyde separation tower 6 receives mixed butyraldehyde from the membrane separator 5 through pipeline 501, thereby achieving separation of normal-isobutyraldehyde. Isobutyraldehyde is extracted through pipeline 603, and normal-butyraldehyde is extracted through pipelines 601 and 602.

[0049] The hydroxypivalaldehyde reactor 7 uses trimethylamine as a catalyst, and condenses formaldehyde and isobutyraldehyde to generate hydroxypivalaldehyde. The hydroxypivalaldehyde reactor 7 is a vertical reactor. A stirring device can be selectively added to the vertical reactor according to actual usage requirements. The hydroxypivalaldehyde reactor 7 receives isobutyraldehyde from pipeline 603 and formaldehyde from pipeline 1902. Under the catalytic action of trimethylamine, isobutyraldehyde and formaldehyde generate hydroxypivalaldehyde. According to the load requirements, multiple hydroxypivalaldehyde reactors 7 can be connected in series or in parallel.

[0050] The light component recovery tower 8 is mainly used to recover unreacted isobutyraldehyde and formaldehyde. The feed to the light component recovery tower 8 enters through pipeline 701, and the isobutyraldehyde and formaldehyde recovered from the top of the tower are returned to the hydroxypivalaldehyde reactor 7 through pipeline 801;

[0051] The neopentyl glycol hydrogenation reactor 9 is a vertical fixed-bed reactor. A hydrogenation catalyst is installed in the neopentyl glycol hydrogenation reactor 9. The hydrogenation catalyst is a copper-based hydrogenation catalyst. The neopentyl glycol hydrogenation reactor 9 is configured as multiple units connected in series. The neopentyl glycol hydrogenation reactor 9 is equipped with a catalyst. Hydroxypivalaldehyde is hydrogenated to produce neopentyl glycol in the neopentyl glycol hydrogenation reactor 9. Pipelines 802 and 901 respectively replenish hydroxypivalaldehyde and hydrogen into the neopentyl glycol hydrogenation reactor 9. Unreacted hydrogen is sent to a propylene and propane recovery unit through a pipeline 903. The propylene and propane recovery unit is a three-tower operation in series, the first two of which are packed towers and the last one is a plate tower.

[0052] The middle part of the neopentyl glycol distillation tower 10 is connected to the neopentyl glycol hydrogenation reactor 9 via pipeline 902 , and qualified neopentyl glycol is obtained via pipeline 1001 .

[0053] The octenal reactor 11 condenses butyraldehyde into octenal under the action of an alkaline liquid catalyst. The n-butyraldehyde pipeline enters through 602. The octenal reactor 11 is vertical. The octenal reactor 11 can be one, two, or three units connected in series. The number of units can be adjusted according to actual requirements. The bottom of the last octenal reactor 11 is equipped with a coalescer and a partition to complete the separation of octenal and water at high temperature.

[0054] The octenal vaporizer 12 is used to gasify octenal. The octenal feed enters through the pipeline 1101, and the octenal gas is extracted from the top through the combined action of heating and circulating hydrogen.

[0055] The octenal hydrogenation reactor 13 is used to hydrogenate octenal to produce isooctyl alcohol. The octenal hydrogenation reactor 13 is configured as a shell and tube reactor and is divided into three sections. The upper section is the superheating section, which is equipped with a superheater for superheating butyraldehyde gas. Steam 1301 enters the superheating section and the steam condensate 1302 is produced through a production pipeline; the middle section is the reaction section, which is equipped with a catalyst. The shell side of the catalyst section is filled with desalted water. The lower section is the quenching section, which is equipped with a condenser. Desalted water 1303 enters the quenching section and heated steam 1304 is produced. The product is produced through the bottom pipeline 1305.

[0056] The octenal hydrogenation circulation compressor 25 is configured as a centrifugal compressor, the inlet of the octenal hydrogenation circulation compressor 25 is connected to the octenal hydrogenation reactor 13, the outlet of the octenal hydrogenation circulation compressor 25 is connected to the octenal vaporizer, and the consumed hydrogen is replenished at the outlet of the octenal hydrogenation circulation compressor 25, the isooctanol distillation tower is configured as two in series, the inlet of the octenal hydrogenation circulation compressor 25 is connected to 1306, the outlet pipeline 2502 is connected to the fresh hydrogen replenishment pipeline 2501, the 2502 pipeline sends hydrogen into the octenal vaporizer 12, and the inert components in the circulating hydrogen are discharged through 1307.

[0057] The isooctyl alcohol distillation tower 14 is used to purify isooctyl alcohol and obtain qualified isooctyl alcohol products through pipeline 1401. The middle part of the isooctyl alcohol distillation tower 14 is connected to the bottom discharge of the octenal hydrogenation reactor 13 through pipeline 1305. There are two isooctyl alcohol distillation towers 14, and the two isooctyl alcohol distillation towers 14 are connected in series to remove light components first and then heavy components.

[0058] The butyraldehyde vaporizer 15 is used to vaporize butyraldehyde. The butyraldehyde feed enters through pipeline 601, and the butyraldehyde gas is produced from the top through the combined action of heating and circulating hydrogen.

[0059] The butyraldehyde hydrogenation reactor 16 is used to hydrogenate butyraldehyde to produce butanol. The butyraldehyde hydrogenation reactor has three sections. The top is the superheating section, with steam 1601 entering the superheating section and a steam condensate 1602 production pipeline. The middle section is the reaction section, which is equipped with a catalyst. The bottom is the quenching section, with desalted water 1603 entering the quenching section and heated steam 1604 being produced. The product is produced through the bottom pipeline 1607.

[0060] The inlet of the butyraldehyde hydrogenation circulation compressor 20 is connected to 1605, and the outlet pipeline 2001 is connected to the fresh hydrogen replenishment pipeline 2002. The pipeline 2001 sends hydrogen into the butyraldehyde vaporizer 15, and the inert components in the circulating hydrogen are discharged through the pipeline 1606.

[0061] The butanol distillation tower 17 is used to purify butanol and obtain qualified butanol products through pipeline 1701. The middle part of the butanol distillation tower 17 is connected to the bottom discharge of the butyraldehyde hydrogenation reactor 16 through pipeline 1607.

[0062] The formaldehyde reactor 18 is equipped with a silver catalyst. The methanol vapor, air, and steam mixture are connected to the formaldehyde reactor 18 through a pipe 1801. Formaldehyde is generated under the action of the silver catalyst. The formaldehyde reactor 18 can be an adiabatic fixed bed with a silver catalyst loaded in the bed layer, or it can be a tubular fixed bed with an iron-molybdenum catalyst loaded in the bed layer.

[0063] The formaldehyde absorption tower 19 is configured as two packed towers connected in parallel. A desalted water addition pipeline 1902 is provided at the top of the formaldehyde absorption tower 19. Formaldehyde is absorbed by the desalted water to form a 37% formaldehyde aqueous solution which enters the hydroxypivalaldehyde reactor 7 through pipeline 1903 for use.

[0064] The propylene absorption tower 21 mainly absorbs propylene and propane with butyraldehyde, and removes alcohols entrained in the hydrogenation tail gas with butyraldehyde. The tail gas pipelines entering the propylene absorption tower 21 include: the outlet pipeline 503 of the membrane separator 5, the outlet pipeline 903 of the neopentyl glycol hydrogenation reactor 9, the outlet pipeline 1607 of the butyraldehyde hydrogenation reactor 16, and the outlet pipeline 1307 of the octenal hydrogenation reactor 13. These pipelines are combined and enter the bottom of the propylene absorption tower 21. The top of the propylene absorption tower 21 is connected to the butyraldehyde pipeline 503 coming from the membrane separator.

[0065] The propylene desorption tower 22 is used to desorb propylene and propane dissolved in butyraldehyde, and the butyraldehyde is recycled back to the propylene absorption tower 21 from the bottom pipeline 2202.

[0066] The propylene-propane separation tower 23 is used to separate propylene and propane. The middle part of the propylene-propane separation tower 23 is connected to the top of the propylene analysis tower 22 through pipeline 2201. The pure propylene obtained at the top is returned to the propylene main feed pipeline 105 through pipeline 2301 for continued use. The pure propane obtained at the bottom of the tower is extracted from pipeline 2302.

[0067] The hydrogen separator 24 is used to separate hydrogen from impurities such as nitrogen and carbon monoxide. The mixed gas enters the hydrogen separator 24 through pipeline 2101 and pipeline 1901. Pipeline 2401 obtains pure hydrogen, and pipeline 2402 obtains impurity mixed gas.

[0068] It should be noted that the raw material parameters and specifications used in the present invention are as follows:

[0069] 1. Specifications of triphenylphosphine carbonyl acetylacetonate rhodium:

[0070]

[0071]

[0072] 2. Specifications of ligand triphenylphosphine:

[0073] Components Content (wt%) Triphenylphosphine 99 triphenylphosphine oxide 1 magnesium 10ppm sodium 5ppm tin 10ppm chlorine 15ppm sulfur 15ppm ash content 100ppm

[0074] 3. Propylene specifications:

[0075]

[0076] 4. Synthesis gas specifications:

[0077]

[0078] 5. Hydrogen specifications:

[0079]

[0080] 6. Methanol purity specifications:

[0081] project index Methanol ≥99.5wt% Potassium permanganate test ≥50 minutes water ≤0.1wt% Carbonyl compounds (calculated as HCHO) 0.002wt%

[0082] like Figure 2As shown, first, in the main reactor and the auxiliary reactor, the catalyst triphenylphosphine carbonyl rhodium acetylacetonate, the ligand triphenylphosphine, and the solvent butyraldehyde are configured into a catalyst solution: the rhodium concentration is 150-600ppm, and the triphenylphosphine concentration is controlled to be 2-5mol%. The liquid levels of the main reactor and the auxiliary reactor are controlled at about 80%. The flow rate of the circulating catalyst entering the upper section is controlled by valve a so that the rhodium content of the catalyst in the upper section is 100-120 ppm. The rhodium content is measured by online analysis. The propylene entering the upper section accounts for 50% of the total propylene feed, and the liquid level in the upper section is controlled at 60-70%. The drop in the liquid level in the upper section is controlled by designing a necking so that the residence time of propylene in the upper section is controlled at 0.5-1 hour. The residence time can be increased by increasing the circulation volume of pipeline 202, and can be reduced by reducing the circulation volume of pipeline 202. Synthesis gas enters the bottom of the upper section through an annular distributor, thereby forming a state of countercurrent contact between synthesis gas and propylene. The reaction temperature is 80-90°C, and the propylene and synthesis gas are fully contacted to react to generate butyraldehyde. 60-90% of the propylene entering the upper section reacts with the synthesis gas, and the unreacted propylene enters the lower section to continue participating in the reaction.

[0083] The flow rate of circulating catalyst entering the lower section is controlled by valve b, ensuring a rhodium content of 120-150 ppm in the upper section catalyst. The rhodium content is measured online. Propylene entering the lower section, representing 40% of the total propylene feed, reacts with unreacted propylene from the upper section. Synthesis gas enters the bottom of the lower section through an annular distributor. Propylene residence time in the lower section is 1-1.5 hours. At a reaction temperature of 80-90°C, after the reaction of propylene and synthesis gas in this section, approximately 5-10% of propylene is present in pipeline 104. Due to the reduced propylene concentration, the reaction cannot continue in the main reactor. To ensure continued reaction, an auxiliary reactor is added to achieve a deeper reaction. At this time, due to the low propylene concentration, the driving force of the reaction is significantly reduced. Therefore, propylene accounting for 10% of the total propylene feed is added to pipeline 203 and then enters the auxiliary reactor. The flow rate of the circulating catalyst entering the auxiliary reactor is controlled by valve c so that the rhodium content of the upper catalyst is 200-250 ppm. The rhodium content is measured by online analysis. In the auxiliary reactor, the unreacted propylene is further converted into butyraldehyde by increasing the catalyst concentration. Through this step, the propylene conversion rate can be maintained at above 98%.

[0084] Since the rhodium concentration in the current prior art is controlled at a high level, at a concentration of 300 ppm, the present invention combines the main reactor with the auxiliary reactor to control the catalyst concentration step by step. Only the concentration of the auxiliary reactor is locally increased to solve the problem of high catalyst concentration and low conversion rate in the prior art, saving a lot of investment costs.

[0085] The method provided by the present invention was used for specific example verification: 4 / 5 of the total amount of propylene and 2 / 3 of the total amount of synthesis gas were introduced into a main reactor through a pipeline, propylene was added to the outlet of a circulating cooler, and a hydroformylation reaction occurred in the main reactor. The reaction temperature was controlled at 80-90° C. and the reaction pressure was 1.5-2.0 MPag. The temperature was controlled by circulating cooling. When the temperature was high, the circulating cooling amount was increased. When the pressure was high, the propylene was discharged to an auxiliary reactor through a top pipeline. Unreacted propylene and synthesis gas were introduced into the auxiliary reactor together with a catalyst solution. 1 / 5 of the total amount of propylene and 1 / 3 of the total amount of synthesis gas were added to the auxiliary reactor. The 1 / 3 of the total amount of synthesis gas was combined with the unreacted gas from the top of the main reactor. The hydroformylation reaction occurred again in the auxiliary reactor, so that the propylene conversion rate reached above 98.5%. The auxiliary reactor liquid level is controlled at approximately 80%, and the butyraldehyde solution containing the catalyst is fed into a falling film evaporator and heated to 100-150°C. The solution then enters the gas-liquid separator in the membrane separator for gas-liquid separation. The liquid phase contains butyraldehyde dissolved with the catalyst, which falls to the bottom and circulates back to the main reactor. The gas phase contains butyraldehyde vapor and nitrogen, propylene, propane, carbon monoxide, hydrogen, etc., which enter the membrane to separate butyraldehyde from nitrogen, propylene, propane, carbon monoxide, and hydrogen. The nitrogen, propylene, propane, carbon monoxide, and hydrogen enter the propylene and propane recovery unit, and the butyraldehyde enters the normal and isobutyraldehyde separation tower. The tower top temperature is controlled at 60-80°C, the tower bottom temperature is controlled at 100-110°C, and the tower pressure is controlled at 0.01-0.07 MPa. Isobutyraldehyde with a purity of 99.85% is obtained at the tower top, and normal butyraldehyde with a purity of 99.85% is obtained in the tower bottom.

[0086] In order to verify that the method provided by the present invention can improve the propylene conversion rate, two groups of existing technologies were used as comparative examples for verification, and the verification results are as follows:

[0087] Comparative Example 1:

[0088] The volume of the main reactor and auxiliary reactor is 5m 3The reactor adds rhodium catalyst 2kg, propylene purity 99.5mol%, hydrogen purity 51v%, carbon monoxide 48.6v% in the synthesis gas feed; Propylene total feed is 500g / h, synthesis gas 361g / h, and it is 120ppm by a valve control epimedulum rhodium concentration, and propylene is controlled to be 250g / h by 106 controlling propylene flow rates and enters epimedulum reaction, and synthesis gas is 190Kg / h by 102 controlling flow rates: it is 150ppm by b valve control epimedulum rhodium concentration, and propylene is controlled to be 200g / h by 106 controlling propylene flow rates and enters epimedulum reaction, and synthesis gas is 144Kg / h by 103 controlling flow rates: a stream is drawn from the main reactor bottom and enters auxiliary reactor, and it is 200ppm by valve c control auxiliary reactor rhodium concentration, and propylene is 100g / h by 107 controlling propylene flow rates, and synthesis gas is 27Kg / h by 303 controlling flow rates, and the component of the incomplete reaction at the main reaction top enters auxiliary reactor by 115 pipelines.

[0089] Comparative Example 1 shows that: 200 kg / h of propylene reacted in the upper stage, with a conversion rate of 80%; 238 kg / h of propylene reacted in the lower stage, with a conversion rate of 95.2%; and the conversion rate of the auxiliary reactor was 98.5%.

[0090] Comparative Example 2:

[0091] According to the current common two-reactor series process, the reactor is equipped with a stirring device and the volume of the two reactors is 5m 3 , 2 kg of rhodium catalyst was added, the purity of propylene was 99.5 mol%, the purity of hydrogen in the synthesis gas feed was 51 v%, and the carbon monoxide was 48.6 v%; the total propylene feed was 500 g / h, and the synthesis gas was 361 g / h, of which all the propylene entered 1 kettle, and the rhodium concentration of the synthesis gas in the first kettle was 250 ppm. Due to the dilution effect of the butyraldehyde generated in the first kettle, the rhodium concentration in the second kettle decreased, and the propylene conversion rate of 1 kettle was 78%, and the propylene conversion rate of 2 kettles was, so the final conversion rate of the ordinary two-kettle process was 93.9%; it was concluded from Comparative Example 2 that the propylene conversion rate was lower than that of the present invention.

[0092] Example 2

[0093] The method provided in Example 1 is used to co-produce butanol, isooctyl alcohol and neopentyl glycol. The co-production process is as follows:

[0094] The mixture of gaseous methanol and air vapor enters the formaldehyde reactor and reacts in the silver catalyst bed to produce formaldehyde. The reaction temperature is 600-680℃ and the pressure is 50-70KPa. The generated formaldehyde gas is rapidly cooled to 150℃ and absorbed by desalted water to produce a 37% pure formaldehyde aqueous solution.

[0095] A 37% formaldehyde aqueous solution, isobutyraldehyde, and trimethylamine as raw materials are fed into a hydroxypivalaldehyde reactor. Under the action of trimethylamine as a catalyst, formaldehyde and isobutyraldehyde generate hydroxypivalaldehyde. The molar ratio of isobutyraldehyde, formaldehyde, and trimethylamine is 1:1.03-1.05. The present invention adopts two hydroxypivalaldehyde reactors connected in series, with a reaction pressure of 0.2-0.4 MPa and a reaction temperature of 70-95°C. The conversion rate of isobutyraldehyde reaches 90-95%. To achieve a higher yield, a light component recovery tower is provided after the hydroxypivalaldehyde reactor. The tower pressure is 0.11 MPa, the tower top temperature is 60-70°C, and the tower bottom temperature is 100-106°C. The isobutyraldehyde, formaldehyde, and trimethylamine recovered from the tower top are returned to the hydroxypivalaldehyde reactor. At this time, the yield based on isobutyraldehyde can reach more than 98%.

[0096] Hydroxypivalaldehyde enters two hydrogenation reactors connected in series. A copper-based catalyst is selected as the catalyst, the main components of which are copper oxide, zinc oxide, aluminum oxide and gallium oxide, and the copper content is greater than or equal to 40wt%. Hydroxypivalaldehyde and hydrogen are reacted at a pressure of 3.5-4.0Mpag and a temperature of 100-150°C to produce neopentyl glycol. At this time, the neopentyl glycol contains impurities such as isobutyraldehyde, formaldehyde, trimethylamine, water and heavy components such as hydroxypivalic acid neopentyl glycol ester generated during the reaction. Impurities are removed in the two neopentyl glycol distillation towers connected in series. The first neopentyl glycol distillation tower mainly produces isobutyraldehyde, formaldehyde, trimethylamine and water from the top. The bottom temperature of the tower is 160-172°C, the top temperature of the tower is 160-172°C, and the top pressure is 200-200°C. The second neopentyl glycol distillation tower mainly produces hydroxypivalic acid neopentyl glycol ester as a by-product from the bottom. The bottom temperature is 170-190°C, the top temperature is 100-155°C, the top pressure is 0.1%, and neopentyl glycol with a purity of 99% is obtained at the top.

[0097] The invention relates to a method for hydrogenating n-butyraldehyde to generate n-butanol. The method adopts a copper-based catalyst whose main components are copper, zinc and aluminum. The hydrogen concentration is required to be 70-90 mol%, the pressure is 0.4-0.6 MPa, and the hydrogenation temperature is 150-200 DEG C. The n-butyraldehyde enters a butyraldehyde vaporizer through an n-butyraldehyde feed pipeline. The feed temperature is 40-60 DEG C, which should not be too high or too low. The temperature of the bottom of the n-butyraldehyde vaporizer is controlled at 70-90 DEG C by a circulating heater. The gaseous butyraldehyde enters an overheating section of a butyraldehyde hydrogenation reactor and is heated to between 110-150 DEG C. The gaseous butyraldehyde then enters a butyraldehyde hydrogenation reaction section containing a hydrogenation catalyst. Under the action of the catalyst, the gaseous butyraldehyde completes a hydrogenation process to generate gaseous butanol. The gaseous butanol enters a quenching section of the butyraldehyde hydrogenation reactor and is cooled to 40-60 DEG C. The n-butanol is condensed into liquid, and hydrogen and the n-butanol liquid are separated at the bottom.

[0098] Hydrogen enters the butyraldehyde hydrogenation recycle compressor and circulates back to the n-butyraldehyde vaporizer to provide power for the gaseous butyraldehyde to enter the butyraldehyde hydrogenation reactor. Inert components such as nitrogen and methane are discharged before the inlet of the butyraldehyde hydrogenation recycle compressor. Fresh hydrogen is replenished at the inlet of the butyraldehyde hydrogenation recycle compressor to maintain a constant hydrogen concentration. The hydrogenated n-butanol, containing trace amounts of butyraldehyde, butyraldehyde trimer, water, isobutanol, and heavy components, enters the distillation system for final purification. The entire purification process is completed within two butanol distillation towers connected in series. The first butanol distillation tower removes butyraldehyde, butyraldehyde trimer, water, isobutanol, and other impurities at the top of the tower. The bottom temperature of the tower is 120-140°C, the top temperature is 90-100°C, and the top pressure is 0.02-0.08 MPag. The second butanol distillation tower extracts heavy components from the bottom of the tower. The bottom temperature is 130-150°C, the top temperature is 110-120°C, and the top pressure is 0.02-0.08 MPag. Qualified n-butanol is obtained from the top of the second butanol distillation tower.

[0099] Butyraldehyde enters a hydroxypivalaldehyde reactor through a pipeline. The present invention adopts two hydroxypivalaldehyde reactors connected in series. Both reactors are equipped with a stirring device. To ensure the stability of the stirring device, the bottom is fixed by a shaft sleeve. The stirring speed is 110-150 rpm. Under the action of a catalyst alkali solution, the butyraldehyde is condensed to generate octenal. The alkali solution concentration is controlled at 0.5-0.9wt%, the reaction temperature is controlled at 110-130°C, and the reaction pressure is controlled at 0.1-0.5Mpag. Since water is generated during the condensation process, a coalescer is installed in a second kettle to separate octenal from water. The water phase is circulated back to the inlet of the first condensation reactor to maintain the reaction temperature and the alkali solution temperature.

[0100] Octenal enters the octenal hydrogenation reactor, catalyzer is selected copper catalyst for use, main component is copper, zinc, aluminium, hydrogen concentration requires 70~90mol%, pressure 0.4~0.6Mpa, hydrogenation temperature 200~280 ℃, octenal enters in the butyraldehyde vaporizer by the octenal feed line, feeding temperature 80~90 ℃, temperature should not be too high or too low, the octenal vaporizer bottom is controlled temperature at 120~150 ℃ by the circulation heater, gaseous phase butyraldehyde enters the butyraldehyde hydrogenation reactor superheated section and is heated between 140~180 ℃, enter the octenal hydrogenation reaction section subsequently, hydrogenation catalyst is housed in the conversion section, under catalyst action, gaseous phase octenal is finished hydrogenation process and generates gaseous phase isooctyl alcohol, gaseous phase isooctyl alcohol enters the isooctyl alcohol hydrogenation reactor quenching section, is cooled to 40~60 ℃, isooctyl alcohol is condensed into liquid, finishes separation of hydrogen and isooctyl alcohol liquid at the bottom. Hydrogen enters the octenal hydrogenation recycle compressor and circulates back to the octenal vaporizer to power the gaseous octenal entering the octenal hydrogenation reactor. Inert components such as nitrogen and methane are discharged before the inlet of the octenal hydrogenation recycle compressor. Fresh hydrogen is replenished at the inlet of the octenal hydrogenation recycle compressor to maintain a constant hydrogen concentration. The hydrogenated isooctanol, containing trace amounts of octenal, butyraldehyde trimer, water, n-butanol, and other impurities, enters the distillation system for final purification. The entire purification process is completed in two series-connected isooctanol distillation towers. The first isooctanol distillation tower removes impurities such as octenal, butyraldehyde trimer, water, and n-butanol at the top of the tower. The bottom temperature of the tower is 150-170°C, the top temperature is 60-100°C, and the top pressure is 10-30 kPa. The second isooctanol distillation tower removes heavy components from the bottom of the tower. The bottom temperature is 150-170°C, the top temperature is 110-130°C, and the top pressure is 10-30 kPa. Qualified isooctanol is obtained from the top of the second isooctanol distillation tower. The butanol, octanol, octenal, and C12 alcohols removed during the butanol and isooctanol production processes are combined to form the C12 mixed alcohol-aldehyde byproduct.

[0101] The exhaust gas from the membrane separator, neopentyl glycol hydrogenation reactor, butyraldehyde hydrogenation reactor, and octenal hydrogenation reactor contains effective components such as propylene, propane, and hydrogen, which are directly discharged and burned, causing great waste. The present invention adopts a method of absorption, analysis, and membrane separation to separate propylene, propane, and hydrogen. The exhaust gas is pressurized to 1.5-1.7 MPa after being collected and enters the middle of a propylene absorption tower at 30-40°C. Butyraldehyde is cooled to 5-10°C from the membrane separator and pressurized to 1.6-1.8 MPa before entering the top of the propylene absorption tower. The propylene and propane in the mixed gas are absorbed, and the unabsorbed methane, hydrogen, carbon monoxide, nitrogen, etc. enter the hydrogen separator. The absorbent and the absorbed propylene, propane, and butyraldehyde are under a pressure of 1.3-1.6 MPa at 105-110°C. The pressure is reduced to 0.7-0.85 MPa through a pressure reducing valve and enters a analysis tower at 90-105°C. A reboiler is provided at the bottom of the propylene absorption tower. The operating pressure of the absorption tower is 1.3-1.6 MPa, the bottom temperature is 100-110°C, and the top temperature is 3-8°C. A reboiler is provided at the bottom of the propylene analysis tower. Propylene and propane are evaporated from the top of the propylene analysis tower with medium-pressure steam and cooled to 0.3-0.6 MPa, 4-7°C, and enter the reflux tank of the propylene analysis tower. The reflux tank is pressurized to 2.2-2.4 MPa and 8-12°C by a pump. A portion of the reflux is recycled back to the top of the propylene analysis tower as the top reflux liquid, and a portion enters the propylene-propane separation tower. The absorbent discharged from the kettle of the propylene analysis tower is 0.5-0.62 MPa and 130-145°C. After being pressurized by a pump or deep-cooled, it is returned to the top of the propylene absorption tower. A reboiler is provided at the bottom of the tower. The operating pressure of the propylene analysis tower is 0.5-0.6 MPa, the bottom temperature is 140-145°C, and the top temperature is 7-8.5°C. The propylene absorption tower of the present invention is divided into two sections. A reboiler is provided at the bottom of the propylene absorption tower. Low-pressure steam is used to distill propylene from propane. After the propane is cooled to 30-35° C., a portion of the propylene is recycled back to the top of the upper section of the propylene absorption tower as a tower top reflux liquid, and another portion is recycled to a butyraldehyde hydrogenation reactor. A reboiler is provided at the bottom of the propylene decomposition tower. The operating pressure of the propylene decomposition tower is 1.8-1.9 MPa, the tower bottom temperature is 55-60° C., and the tower top temperature is 40-46° C.

[0102] The top gas of the analysis tower and the top gas of the formaldehyde absorption tower mainly contain methane, hydrogen, carbon monoxide, nitrogen, carbon dioxide, etc. The temperature is reduced to 35-50°C before entering the hydrogen separator. The hydrogen separator is equipped with a separator composed of fiber membranes. The permeation rate of hydrogen in the fiber membranes is faster than that of methane, carbon monoxide and nitrogen. Under the action of pressure difference, hydrogen preferentially passes through the fiber membranes and is enriched. Methane, carbon monoxide and nitrogen have slow permeation rates and are thus retained. The hydrogen separator can eventually achieve a hydrogen purity of 99wt%, which is recycled to the butyraldehyde hydrogenation circulating compressor. The selected fiber membranes should have a low permeability to carbon monoxide, and the carbon monoxide in the hydrogen is controlled to be lower than 10ppm, because carbon monoxide is a poison to the catalyst in the butyraldehyde hydrogenation system.

[0103] In summary, propylene, synthesis gas, hydrogen, methanol and air are used as raw materials, propylene and synthesis gas are reacted with each other in the presence of a catalyst triphenylphosphine carbonyl acetylacetonate rhodium and a ligand triphenylphosphine to synthesize butyraldehyde through two tower reactors, butyraldehyde and the mixed catalyst and ligand are evaporated in a falling film evaporator and then enter a membrane separator, butyraldehyde is separated from the catalyst and unreacted products in the membrane separator, the separated butyraldehyde enters a normal-isobutyraldehyde separation tower, isobutyraldehyde is obtained at the top of the tower, and normal-butyraldehyde is obtained in the bottom of the tower; methanol and air are reacted with each other in the presence of an electrolytic silver catalyst or an iron-molybdenum catalyst to generate formaldehyde, and a 37% formaldehyde solution is obtained through two absorption towers, the formaldehyde solution and isobutyraldehyde are reacted with each other in the presence of a tertiary amine catalyst to generate hydroxypivalaldehyde, hydroxypivalaldehyde is liquid-phase hydrogenated with a copper-based catalyst to generate neopentyl glycol, and the neopentyl glycol is subjected to a distillation tower to remove impurities. To obtain qualified neopentyl glycol products, part of the n-butyraldehyde enters the butanol production line, the n-butyraldehyde is gas-phase hydrogenated over a copper-based catalyst to generate n-butanol, and a qualified n-butanol product is obtained through distillation. Part of the n-butyraldehyde enters the octanol production line, the n-butyraldehyde is condensed under the action of an alkaline liquid catalyst to generate octenal, the octenal is preliminarily gas-phase hydrogenated over a copper-based catalyst, the product after the preliminarily hydrogenated is liquid-phase hydrogenated over a nickel-based catalyst to generate isooctyl alcohol, and the isooctyl alcohol is distilled to obtain a qualified isooctyl alcohol product. In this process, tail gas generated in the butyraldehyde production process, the formaldehyde production process, the butanol production process, and the octanol production process contains effective components such as propylene, propane, and hydrogen. The present invention adopts a butyraldehyde absorption and analysis method to obtain high-purity propylene, which is returned to the system for further reaction, the high-purity hydrogen is used for hydrogenation, and the high-purity propane is recovered for use.

[0104] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for co-producing butanol, octanol and neopentyl glycol, characterized in that: The steps include: S1. Synthesis gas and propylene are reacted in the main reactor to generate butyraldehyde via the action of catalyst. The circulating cooler controls the reaction heat, and the unreacted materials enter the auxiliary reactor to continue the reaction. S2, the discharge from the auxiliary reactor is heated in a falling film evaporator and then enters a membrane separator to separate light components, catalyst and butyraldehyde. The catalyst returns to the main reactor and the mixed butyraldehyde enters a normal-isobutyraldehyde separation tower; S3, a normal-isobutyraldehyde separation tower separates isobutyraldehyde and normal-butyraldehyde; S4, isobutyraldehyde and formaldehyde generate hydroxypivalaldehyde in a hydroxypivalaldehyde reactor, unreacted components are recovered in a light component recovery tower and returned to the hydroxypivalaldehyde reactor, hydroxypivalaldehyde is hydrogenated in a neopentyl glycol hydrogenation reactor to generate neopentyl glycol, and purified in a neopentyl glycol distillation tower; S5, n-butyraldehyde is condensed into octenal in an octenal reactor, which is then gasified in an octenal vaporizer and hydrogenated in an octenal hydrogenation reactor to produce isooctyl alcohol, hydrogen is circulated through an octenal hydrogenation circulation compressor, and the isooctyl alcohol is purified through an isooctyl alcohol distillation tower; S6, after the n-butyraldehyde is vaporized in the butyraldehyde vaporizer, it is hydrogenated in the butyraldehyde hydrogenation reactor to produce butanol, the hydrogen is circulated through the butyraldehyde hydrogenation circulation compressor, and the butanol is purified through the butanol distillation tower; S7, methanol vapor, air, and steam mixture generate formaldehyde in the formaldehyde reactor, which is absorbed in the formaldehyde absorption tower and then used for subsequent reactions; S8, the tail gas is absorbed by the propylene absorption tower and propane, and is analyzed by the propylene analysis tower, and the propylene-propane separation tower separates pure propylene and propane; S9. The mixed gas is separated into pure hydrogen and impurity mixed gas through a hydrogen separator.

2. The method for co-producing butanol, octanol and neopentyl glycol according to claim 1, wherein: The main reactor is a two-stage reaction, which reacts with the catalyst to generate butyraldehyde during the reaction. A butterfly gate is used to limit the flow between the upper and lower sections to control the upper end liquid level. The upper section is provided with a porous filler area and a distributor to ensure that the synthesis gas and propylene are fully in contact with the catalyst. Circulating coolers are provided at the bottom of the upper and lower sections to adjust the temperature. The catalyst is set as triphenylphosphine carbonyl acetylacetonate rhodium and the ligand triphenylphosphine. The inlet of the circulating cooler is connected to the main reactor, and the outlet of the circulating cooler is connected to the propylene feed pipeline. The coolant returns to the upper and lower sections of the main reactor to control the reaction heat.

3. The method for co-producing butanol, octanol and neopentyl glycol according to claim 2, wherein: The auxiliary reactor is connected to the circulating cooler through a pipeline, and the pipeline is connected to the propylene pipeline and then enters the auxiliary reactor together. The unreacted propylene and synthesis gas are combined with the discharge from the main reactor and then enter the auxiliary reactor to continue the reaction.

4. The method for co-producing butanol, octanol and neopentyl glycol according to claim 3, wherein: The inlet of the falling film evaporator is connected to the discharge pipeline of the auxiliary reactor, and the outlet of the falling film evaporator is connected to the membrane separator for heating the discharge. The membrane separator is equipped with a gas-liquid separator and a membrane for gas-liquid separation.

5. The method for co-producing butanol, octanol and neopentyl glycol according to claim 4, wherein: The normal-isobutyraldehyde separation tower is configured as a plate tower, which receives mixed butyraldehyde from a membrane separator to separate normal-isobutyraldehyde. Isobutyraldehyde is extracted from the top of the tower, and normal-butyraldehyde is extracted from the side line of the bottom of the tower.

6. The method for co-producing butanol, octanol and neopentyl glycol according to claim 5, wherein: The hydroxypivalaldehyde reactor uses trimethylamine as a catalyst to condense formaldehyde and isobutyraldehyde to generate hydroxypivalaldehyde. The hydroxypivalaldehyde reactor is a vertical reactor.

7. The method for co-producing butanol, octanol and neopentyl glycol according to claim 1, wherein: The neopentyl glycol hydrogenation reactor is a vertical fixed-bed reactor. A hydrogenation catalyst is installed in the neopentyl glycol hydrogenation reactor. Multiple neopentyl glycol hydrogenation reactors are connected in series.

8. The method for co-producing butanol, octanol and neopentyl glycol according to claim 1, wherein: The octenal hydrogenation circulation compressor is configured as a centrifugal compressor, the inlet of the octenal hydrogenation circulation compressor is connected to the octenal hydrogenation reactor, the outlet of the octenal hydrogenation circulation compressor is connected to the octenal vaporizer, and the consumed hydrogen is replenished at the outlet of the octenal hydrogenation circulation compressor, and the isooctanol distillation tower is configured as two units connected in series.

9. The method for co-producing butanol, octanol and neopentyl glycol according to claim 1, wherein: The formaldehyde reactor is equipped with a silver catalyst, and a mixture of methanol vapor, air and steam is connected to the formaldehyde reactor through a pipeline, and formaldehyde is generated under the action of the silver catalyst.

10. The method for co-producing butanol, octanol and neopentyl glycol according to claim 1, characterized in that: The formaldehyde absorption tower is configured as two packed towers connected in parallel. A desalted water feeding pipeline is provided on the top of the formaldehyde absorption tower. After formaldehyde is absorbed by the desalted water, a 37% formaldehyde aqueous solution is formed and enters the hydroxypivalaldehyde reactor through the pipeline for use.

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