Apparatus and method for preparing epoxidized soybean oil by isobutane co-oxidation

Abstract

A device and method for preparing epoxy soybean oil by isobutane co-oxidation, comprising a peroxidation reactor, an acid remover, an isobutane recovery tower, a concentration tower, an epoxidation reactor, an evaporator and a stripping tower connected in sequence, the peroxidation reactor is used for providing space and environment for peroxidation reaction, and the acid remover is used for neutralizing acidic substances in reaction products; the isobutane recovery tower is used for recovering isobutane in reaction products after acid removal, the concentration tower is used for concentrating TBHP / TBA solution after isobutane removal and introducing the TBHP / TBA solution into the reactor for recycling; the epoxidation reactor is used for providing space and environment for epoxidation reaction, the evaporator is used for gas-liquid separation of reaction products after epoxidation reaction, and the stripping tower is connected with the evaporator and used for stripping liquid mixture with high BM content, so as to separate BM in the liquid mixture from gaseous TBHP and / or TBA. The reaction speed is fast, and the co-produced TBA product has high value.

Description

Technical Field

[0001] This invention belongs to the field of epoxidized soybean oil manufacturing technology, and relates to an apparatus and method for preparing epoxidized soybean oil by isobutane co-oxidation, and more particularly to an apparatus and method for preparing epoxidized soybean oil and producing tert-butanol by isobutane co-oxidation. Background Technology

[0002] Epoxidized soybean oil is a product of soybean oil after epoxidation. It possesses excellent heat resistance, light resistance, interpenetration properties, and low-temperature flexibility, and has low volatility and low toxicity. It is primarily used as a plasticizer and stabilizer in polyvinyl chloride (PVC) processing, such as in the production of PVC doors, windows, pipes, and films, as well as transparent PVC products (transparent bottles, boxes, food and pharmaceutical packaging materials). Furthermore, epoxidized soybean oil can be used to produce new products such as vegetable oil-based polyols, propylene glycol ester epoxidized soybean oil fatty acids, and hydroxylated epoxidized soybean oil.

[0003] Epoxidized soybean oil is generally prepared by epoxidation of soybean oil with an oxidant under catalysis. Hydrogen peroxide is typically used as the oxygen source, organic acids as the oxygen carrier, and catalysts include inorganic acids, inorganic acid salts, organic acids, organic acid salts, ion exchange resins, and enzyme catalysts. Patent document CN101974369B discloses a new catalyst-free method for epoxidation of soybean oil using hydrogen peroxide as the oxygen source and tungsten trioxide as the oxygen carrier; however, this method requires a phase transfer catalyst and a pH buffer, resulting in a complex reaction system. Currently, industrially mature epoxidized soybean oil processes typically use formic acid as the oxygen carrier and sulfuric acid as the catalyst. This process suffers from problems such as long reaction times and the generation of large amounts of acidic wastewater.

[0004] Alkyl organic peroxides are also excellent oxidants for the epoxidation of soybean oil, with advantages such as no acidic wastewater generated in the reaction system and fast reaction speed. Patent document CN103111329 discloses a process for epoxidizing fatty acid esters using tert-butyl hydrogen peroxide (TBHP) aqueous solution as oxygen source and molybdenum-based metal oxides grafted onto a polymer support as catalyst; Matteo Gidotitt (J. Mol. Catal. A: Chem., 2006, 250(1-2). 218-225) reported a method for epoxidizing fatty acid methyl esters using TBHP decane solution as oxygen source and four different Ti-Si molecular sieves as catalysts.

[0005] However, the aforementioned TBHP epoxidation method suffers from problems such as complex catalyst preparation processes, high cost, and limited application times. Furthermore, the TBHP oxidant used has at least one of the following drawbacks: water content in the oxidant, complex preparation process, and complex post-reaction treatment. Therefore, the soybean oil epoxidation process using TBHP as the oxidant requires further optimization. Summary of the Invention

[0006] This invention provides a method for preparing epoxidized soybean oil by isobutane co-oxidation. The method involves preparing TBHP by isobutane oxidation, deacidifying and removing impurities from the reaction product solution, preparing a TBHP / TBA solution by distillation, and then epoxidizing the solution with soybean oil under the catalysis of a soluble molybdenum catalyst to synthesize epoxidized soybean oil. After flash evaporation and stripping, TBHP is recovered, and the oil is then washed with water and dried to obtain high-quality epoxidized soybean oil.

[0007] In this invention, unless otherwise specified, TBHP is the abbreviation for tert-butyl hydroperoxide, TBA is the abbreviation for tert-butanol, and BM is the abbreviation for epoxidized soybean oil.

[0008] Specifically, the present invention provides the following technical solution:

[0009] An apparatus for preparing epoxidized soybean oil by isobutane co-oxidation, the apparatus comprising:

[0010] An oxidation reactor, wherein the oxidation reactor is used to provide space and environment for the oxidation reaction of a first reactant, the oxidation reactor including a feed inlet and an outlet; the first reactant includes isobutane, oxygen and a catalyst;

[0011] An acid remover, which is connected to the peroxidation reactor, is used to neutralize acidic substances in the reaction products;

[0012] An isobutane recovery tower is connected to an acid remover to recover isobutane from the reaction products after acid removal, and to introduce the recovered isobutane as a reaction feedstock into a peroxidation reactor.

[0013] A concentration tower, connected to an isobutane recovery tower, is used to concentrate the TBHP / TBA solution after isobutane removal;

[0014] An epoxidation reactor is provided to provide space and environment for the epoxidation reaction of a second reactant. The epoxidation reactor includes a feed inlet and a reactant outlet. The second reactant includes TBA, TBHP, and soybean oil. The epoxidation reactor is connected to a concentration tower to introduce a concentrated TBHP / TBA solution from the concentration tower as a reactant into the epoxidation reactor.

[0015] An evaporator is connected to the reactant outlet of the epoxidation reactor. The evaporator is used to perform gas-liquid separation on the reactants after the epoxidation reaction to obtain a gaseous TBA / TBHP mixture with high TBHP content and a liquid mixture with high BM content.

[0016] A stripping tower, connected to an evaporator, is used to strip a liquid mixture with a high BM content, separating BM from gaseous TBHP and / or TBA in the liquid mixture; the stripping tower is also connected to a concentration tower, which is used to concentrate gaseous TBHP and / or TBA to obtain TBA vapor and liquid TBHP, and the liquid TBHP is introduced into the epoxidation reactor as a raw material for recycling.

[0017] A method for preparing soybean oil by co-oxidation of isobutane, the method comprising the following steps:

[0018] 1) The first reaction feedstock, including isobutane, catalyst and oxygen, is added to the peroxidation reactor to carry out the peroxidation reaction and prepare a first mixed system containing tert-butyl hydrogen peroxide, tert-butanol and isobutane;

[0019] 2) The first mixture in step 1) is deacidified to obtain a second mixture containing isobutane, tert-butyl hydroperoxide and tert-butanol;

[0020] 3) After removing isobutane from the second mixture system in step 2), mix it with soybean oil and catalyst to obtain the second reaction raw material, and carry out the epoxidation reaction to prepare crude epoxidized soybean oil and TBA / TBHP vapor.

[0021] 4) The crude epoxidized soybean oil extracted in step 3) is evaporated and separated to obtain gaseous and liquid products.

[0022] The solution of the present invention achieves the following beneficial effects:

[0023] This invention provides a method for preparing epoxidized soybean oil through isobutane co-oxidation. A TBHP / TBA solution is prepared via isobutane catalytic oxidation, and after refining, it is used as an oxidant in the epoxidation of soybean oil. The epoxidation reaction is a homogeneous reaction using soluble molybdenum as a catalyst. During the reaction, most of the byproduct TBA and unreacted TBHP are collected and returned to the TBHP solution concentration process. The raw material for preparing the TBHP oxidant is recovered, and the byproduct TBA is separated. The byproduct TBA can be used to produce products such as MTBE, isobutylene, and methyl methacrylate. Compared with existing technologies, the homogeneous epoxidation process of soybean oil prepared by isobutane oxidation using TBHP / TBA has the advantages of fast reaction speed, no water involvement in the reaction process, and high epoxy value of the product. The co-produced TBA product has high value and a broad downstream market. Therefore, the epoxidized soybean oil / TBA co-production process is a new, green, environmentally friendly, economical, and efficient epoxidized soybean oil production process. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the apparatus for preparing epoxidized soybean oil by co-oxidation of isobutane in this invention.

[0025] In the diagram, 1-peroxide reactor, 2-acid remover, 3-isobutane recovery tower, 4-concentration tower, 5-epoxidation reactor, 6-evaporator, 7-stripping tower. Detailed Implementation

[0026] Apparatus for preparing epoxidized soybean oil by co-oxidation of isobutane

[0027] As mentioned above, the present invention provides an apparatus for preparing epoxidized soybean oil by isobutane co-oxidation, the apparatus comprising:

[0028] An oxidation reactor, wherein the oxidation reactor is used to provide space and environment for the oxidation reaction of a first reactant, the oxidation reactor including a feed inlet and an outlet; the first reactant includes isobutane, oxygen and a catalyst;

[0029] An acid remover, which is connected to the peroxidation reactor, is used to neutralize acidic substances in the reaction products;

[0030] An isobutane recovery tower, wherein the isobutane recovery unit is connected to an acid remover, is used to recover isobutane from the reaction products after acid removal, and introduces the recovered isobutane as a reaction feedstock into the peroxidation reactor;

[0031] A concentration tower, connected to an isobutane recovery tower, is used to concentrate the TBHP / TBA solution after isobutane removal;

[0032] An epoxidation reactor is provided to provide space and environment for the epoxidation reaction of a second reactant. The epoxidation reactor includes a feed inlet and a reactant outlet. The second reactant includes TBA, TBHP, and soybean oil. The epoxidation reactor is connected to a concentration tower to introduce a concentrated TBHP / TBA solution from the concentration tower as a reactant into the epoxidation reactor.

[0033] An evaporator is connected to the reactant outlet of the epoxidation reactor. The evaporator is used to perform gas-liquid separation on the reactants after the epoxidation reaction to obtain a gaseous TBA / TBHP mixture with high TBHP content and a liquid mixture with high BM content.

[0034] A stripping tower, connected to an evaporator, is used to strip a liquid mixture with a high BM content, separating BM from gaseous TBHP and / or TBA in the liquid mixture; the stripping tower is also connected to a concentration tower, which is used to concentrate gaseous TBHP and / or TBA to obtain TBA vapor and liquid TBHP, and the liquid TBHP is introduced into the epoxidation reactor as a raw material for recycling.

[0035] According to an embodiment of the present invention, the raw material inlet of the peroxidation reactor is connected to a raw material supply mechanism via a pipeline. Preferably, the number of raw material inlets can be one or more, and the raw material entering the raw material inlet can be a single raw material or a mixture of raw materials.

[0036] According to an embodiment of the present invention, the deacidifier includes at least two inlets and at least one outlet, for example, two inlets and two outlets, wherein one inlet is connected to the outlet of the peroxidation reactor for introducing reaction products into the deacidifier, one inlet is connected to the outside for introducing an alkaline solution into the deacidifier; one outlet is used to discharge the neutralized brine, and one outlet is used to discharge the deacidified reaction products; the deacidified reaction products include isobutane, TBA, and TBHP.

[0037] According to an embodiment of the present invention, the isobutane recovery tower includes at least one inlet and two outlets. The inlet is connected to the outlet of the deacidifier from which the reaction product is discharged, one outlet is connected to a concentration tower, and the other outlet is connected to a peroxidation reactor for introducing isobutane as a reaction feedstock into the peroxidation reactor.

[0038] According to an embodiment of the present invention, the concentration tower includes at least one inlet and at least one outlet, preferably the concentration tower includes two inlets and two outlets, wherein one inlet is connected to the outlet of the isobutane recovery tower, and the other inlet is connected to the gas phase outlet of the epoxidation reactor, flash evaporation and stripping tower; one outlet is connected to the epoxidation reactor, and the other outlet is used to discharge TBA gas.

[0039] According to an embodiment of the present invention, the concentration tower includes two outlets, one outlet located at the top of the concentration tower and the other outlet located at the bottom of the concentration tower. After the gas phase flows out of the outlet at the top, it is divided into two paths. One path directly extracts TBA product, and the other path is connected to the stripping tower to introduce gaseous TBA gas into the stripping tower. The outlet located at the bottom is connected to the inlet of the epoxidation reactor for introducing the concentrated TBA / TBHP into the epoxidation reactor.

[0040] According to an embodiment of the present invention, the concentration tower further includes a reboiler, a condenser, and a reflux tank, wherein the reboiler is disposed in the lower part of the concentration tower, and the condenser and the reflux tank are disposed in the upper part of the concentration tower.

[0041] According to an embodiment of the present invention, a purge liquid is also provided in the passage connecting the concentration tower and the epoxidation reactor to balance the accumulated amount of impurities in the system.

[0042] According to an embodiment of the present invention, the concentration tower is a conventional distillation tower, preferably, the theoretical stages of the concentration tower are 10 to 25, more preferably 15 to 20.

[0043] According to an embodiment of the present invention, the raw material inlet of the epoxidation reactor is connected to a raw material supply mechanism via a pipeline. Preferably, the number of raw material inlets can be one or more, and the raw material entering the raw material inlet can be a single raw material or a mixture of raw materials.

[0044] According to an embodiment of the present invention, the evaporator includes an inlet and several outlets, the inlet of the evaporator being connected to the reactant outlet of the reactor, for example, via a pipe.

[0045] According to an embodiment of the present invention, the plurality of outlets of the evaporator are arranged at different positions on the evaporator. Preferably, the plurality of outlets are arranged at different heights on the evaporator according to the height corresponding to the fraction. For example, the evaporator is provided with two outlets, one of which is located at the top of the evaporator (for discharging a gaseous TBA / TBHP mixture with a high TBHP content), and the other outlet is located at the bottom of the evaporator (for discharging a liquid mixture with a high BM content).

[0046] According to an embodiment of the present invention, the evaporator is a conventional evaporator in the art, such as a falling film evaporator.

[0047] According to an embodiment of the present invention, the stripping tower includes at least two inlets and at least one outlet; wherein, one inlet of the stripping tower is connected to the outlet at the bottom of the evaporator, the inlet being located at the upper part of the stripping tower for introducing a liquid mixture with a high BM content into the stripping tower, and the other inlet being located at the lower part of the stripping tower for introducing gaseous TBA gas; the outlet of the stripping tower is used to discharge the separated crude epoxidized soybean oil, and the outlet is located at the bottom of the stripping tower.

[0048] According to an embodiment of the present invention, the stripping tower further includes a gas outlet disposed at the top for discharging TBA and TBHP gas carried out from soybean oil; and a second outlet located at the bottom of the stripping tower for discharging a mixture with high BM content separated from the gaseous TBA / TBHP mixture.

[0049] According to an embodiment of the present invention, the stripping tower is a conventional stripping tower in the art, preferably, the theoretical number of the stripping tower is 5 to 20, more preferably 7 to 15.

[0050] According to an embodiment of the present invention, the above-described connection is a common connection method in the art, such as a connection via a pipe.

[0051] [Method for preparing epoxidized soybean oil by co-oxidation of isobutane]

[0052] As mentioned above, a method for preparing soybean oil by co-oxidation of isobutane includes the following steps:

[0053] 1) The first reaction feedstock, including isobutane, catalyst and oxygen, is added to the peroxidation reactor to carry out the peroxidation reaction and prepare a first mixed system containing tert-butyl hydrogen peroxide, tert-butanol and isobutane;

[0054] 2) The first mixture in step 1) is deacidified to obtain a second mixture containing isobutane, tert-butyl hydroperoxide and tert-butanol;

[0055] 3) After removing isobutane from the second mixture system in step 2), mix it with soybean oil and catalyst to obtain the second reaction raw material, and carry out the epoxidation reaction to prepare crude epoxidized soybean oil and TBA / TBHP vapor.

[0056] 4) The crude epoxidized soybean oil extracted in step 3) is evaporated and separated to obtain gaseous and liquid products.

[0057] According to an embodiment of the present invention, after step 4), the following steps are further included:

[0058] 5) After the gaseous product separated by evaporation is added to the concentration tower for concentration and enrichment, a gaseous TBA and TBHP / TBA mixture is obtained. The TBHP / TBA mixture is then introduced into step 3) as a reaction raw material for the epoxidation reaction for recycling.

[0059] According to an embodiment of the present invention, after step 4), the following steps are further included:

[0060] 6) Add the evaporated liquid product to the stripping tower, and introduce TBA steam into the stripping tower to remove TBHP from the liquid product to form TBHP / TBA mixed steam, which is then introduced into the concentration tower.

[0061] According to an embodiment of the present invention, steps 5) and 6) can be performed simultaneously or at different times.

[0062] According to an embodiment of the present invention, after step 5), the following steps are further included:

[0063] 7) After the TBHP / TBA mixed steam is concentrated in the concentration tower, TBA steam is taken out from the top of the concentration tower. A portion of the TBA steam is sent to the condenser in the concentration tower for steam reflux; the other portion is heated to form superheated steam and then fed into the stripping tower to remove TBHP from the liquid phase product.

[0064] According to an embodiment of the present invention, in step 1), the isobutane can be fresh isobutane, or it can be recycled isobutane, such as isobutane that did not react in the reaction, or it can be a mixture of fresh isobutane and recycled isobutane. The amount of fresh isobutane added is to replenish the isobutane consumed in the reaction.

[0065] According to an embodiment of the present invention, the amount of fresh isobutane added is 40-50 wt% of the total amount of isobutane added in the reaction system, preferably 43-48 wt% of the total amount of isobutane added in the reaction system.

[0066] According to an embodiment of the present invention, in step 1), the catalyst is an organometallic molybdenum catalyst or an organometallic vanadium catalyst, preferably an organometallic molybdenum catalyst, such as molybdenum glycol.

[0067] According to an embodiment of the present invention, the amount of catalyst added to the reaction system is 2 to 30 ppm, preferably 10 to 20 ppm, for example 15 ppm.

[0068] According to an embodiment of the present invention, the amount of organometallic molybdenum catalyst added to the reaction system is 2-30 ppm, preferably 15 ppm.

[0069] According to an embodiment of the present invention, the catalyst can be added to a good solvent to form a solution before being added to the reaction system, or it can be dissolved in a TBHP / TBA solution before being added to the reaction system.

[0070] According to an embodiment of the present invention, in step 1), the reaction is carried out in an isobutane oxidation reactor, which is a liquid-phase oxidation reactor known in the art.

[0071] According to an embodiment of the present invention, in step 1), the isobutane, oxygen and catalyst can be added to the reactor separately for reaction, or they can be mixed first and then added to the reactor.

[0072] According to an embodiment of the present invention, in step 1), the temperature of the oxidation reaction is 120-140°C, and preferably the temperature of the reaction is 133-139°C.

[0073] According to an embodiment of the present invention, in step 1), the reaction pressure is 2.6 to 4.0 MPa, preferably 2.8 to 3.5 MPa.

[0074] According to an embodiment of the present invention, in step 1), the first mixed system comprises, by mass, tert-butyl hydroperoxide with a content of less than or equal to 10 wt%, tert-butanol with a content of greater than or equal to 30 wt%, and water with a content of 2-3 wt%.

[0075] According to an embodiment of the present invention, the acid value (calculated as acetic acid) of the first mixture is 1.5-2.5 wt% by weight.

[0076] According to an embodiment of the present invention, the deacidification in step 2) includes contacting an alkaline solution with the first mixed system.

[0077] According to an embodiment of the present invention, the alkaline solution is selected from hydroxides or carbonates of alkaline earth metals, preferably sodium hydroxide, sodium carbonate, etc., for example, sodium hydroxide.

[0078] According to an embodiment of the present invention, step 2) includes the following steps:

[0079] The first mixed system produced in step 1) is first neutralized with an alkaline solution, and the two phases are separated into a second mixed system phase and a brine phase.

[0080] According to an embodiment of the present invention, the acid value of the second mixture after the neutralization reaction is less than 0.3% (based on acetic acid), preferably less than 0.2% (based on acetic acid).

[0081] According to an embodiment of the present invention, the mass concentration of the alkaline solution is 15-40%, preferably 20-30%.

[0082] According to an embodiment of the present invention, the amount of alkaline solution used is 0.90 to 0.95 equivalents of the total acid in the first mixed system, preferably 0.92 to 0.93 equivalents of the total acid in the first mixed system.

[0083] According to an embodiment of the present invention, after deacidification in step 2), the following step is further included: washing the product after deacidification with water.

[0084] According to an embodiment of the present invention, the water washing uses pure water, and the amount of pure water used for the water washing is 1 / 4 to 1 / 2 of the weight of the sodium hydroxide solution.

[0085] According to an embodiment of the present invention, after washing with water, the mixture is divided into a second mixed system phase and a brine phase. The second mixed system includes isobutane, tert-butanol, tert-butyl hydroperoxide, some impurities, and a small amount of water.

[0086] According to an embodiment of the present invention, the neutralization of the alkaline solution with the first mixed system can be carried out in a conventional static mixer or in a conventional extraction tower, such as a packed tower or a sieve plate tower.

[0087] According to an embodiment of the present invention, step 2) further includes the following step: removing the brine phase from the deacidifier.

[0088] According to an embodiment of the present invention, the removal of isobutane from the second mixed system in step 3) includes the following steps: introducing the second mixed system into an isobutane recovery tower to remove isobutane.

[0089] According to an embodiment of the present invention, the bottom temperature of the isobutane recovery tower for removing isobutane is 74-76°C.

[0090] According to an embodiment of the present invention, the top temperature of the isobutane removal column is -21 to -19°C, and the top pressure of the isobutane removal column is -0.03 MPa.

[0091] According to an embodiment of the present invention, the top reflux ratio of the isobutane removal column is (0.5-1.5):1, preferably (1-1.2):1.

[0092] According to an embodiment of the present invention, the second mixed system after water washing is fed into an isobutane removal tower. Isobutane is collected from the top of the tower for recycling, and a TBA solution containing TBHP is collected from the bottom of the tower. The TBHP / TBA solution collected from the bottom of the tower, together with the TBA material from steps 4) and 5), enters a TBHP concentration tower for distillation and concentration. TBA is collected from the top of the tower, while most of the water and impurities are removed. The TBHP / TBA solution collected from the bottom of the tower can be directly used for epoxidation.

[0093] According to an embodiment of the present invention, the bottom temperature of the concentration tower is 74-76°C, the top temperature of the concentration tower is 51-53°C, and the top pressure of the concentration tower is -0.07 to -0.075 MPa.

[0094] According to an embodiment of the present invention, the top reflux ratio of the concentration tower is (1-5):1.

[0095] According to an embodiment of the present invention, the TBHP / TBA solution collected from the concentration tower has a TBHP content of 50-60%, a water content of less than 0.6%, and an acid value of less than 0.5% (based on acetic acid).

[0096] According to an embodiment of the present invention, in step 3), the molar ratio of soybean oil double bonds to TBHP is 1:1.5-2.5, the catalyst is a soluble molybdenum catalyst, and the concentration of the molybdenum catalyst in the reaction system is 30-120 ppm, preferably 60-90 ppm.

[0097] According to an embodiment of the present invention, in step 3), the reaction temperature of the epoxidation reaction is 85-120°C, preferably 100-115°C.

[0098] According to an embodiment of the present invention, the pressure of the epoxidation reaction is atmospheric pressure or slightly positive pressure.

[0099] According to an embodiment of the present invention, in step 3), the epoxidation reaction takes 60-90 minutes, preferably 70-80 minutes, for example 75 minutes.

[0100] According to an embodiment of the present invention, in step 4), the evaporation is flash evaporation, preferably direct flash evaporation under reduced pressure.

[0101] According to an embodiment of the present invention, the pressure of the flash tube is -0.05 to -0.09 MPa.

[0102] According to an embodiment of the present invention, in step 6), the TBA steam used for stripping is either TBA steam recovered from the concentration tower or TBA steam that has been further purified.

[0103] The apparatus and method of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0104] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods, and the concentrations in the following examples are all mass percentages.

[0105] Example 1

[0106] See Figure 1 As shown, an apparatus for preparing epoxidized soybean oil by isobutane co-oxidation includes:

[0107] Peroxidation reactor 1 is used to provide space and environment for the co-oxidation reaction of the first reaction raw materials. Peroxidation reactor 1 includes a raw material inlet and an outlet. The first reaction raw materials include isobutane, oxygen and catalyst. In this embodiment, the raw material inlet of peroxidation reactor 1 is connected to the raw material supply mechanism through a pipeline. Preferably, the number of raw material inlets can be one or more, and the raw material entering the raw material inlet can be a single raw material or a mixture of raw materials.

[0108] Acid remover 2 is connected to peroxidation reactor 1 and is used to neutralize acidic substances in the reaction products. The acid remover 2 includes at least two inlets and at least one outlet, for example, two inlets and two outlets. One inlet is connected to the outlet of peroxidation reactor 1 for introducing the reaction products into the acid remover 2, and one inlet is connected to the outside for introducing an alkaline solution into the acid remover 2. One outlet is used to discharge the neutralized brine, and one outlet is used to discharge the reaction products after acid removal. The reaction products after acid removal include isobutane, TBA, and TBHP.

[0109] Isobutane recovery tower 3 is connected to acid remover 2 and is used to recover isobutane from the reaction product after acid removal, and to introduce the recovered isobutane as a reaction feedstock into peroxidation reactor 1. Isobutane recovery tower 3 includes at least one inlet and two outlets. The inlet is connected to the outlet of acid remover 2 that discharges the reaction product, one outlet is connected to concentration tower 4, and the other outlet is connected to peroxidation reactor 1, for introducing isobutane as a reaction feedstock into peroxidation reactor 1.

[0110] Concentration tower 4 is connected to isobutane recovery tower 3 and is used to concentrate the TBHP / TBA solution after isobutane removal.

[0111] Epoxidation reactor 5 provides space and environment for the epoxidation reaction of the second reaction raw material. Epoxidation reactor 5 includes a raw material inlet and a reactant outlet. The second reaction raw material includes TBA, TBHP and soybean oil. Epoxidation reactor 5 is connected to concentration tower 4 and is used to introduce the concentrated TBHP / TBA solution in concentration tower 4 as a reaction raw material into epoxidation reactor 5. Epoxidation reactor 5 can be any reactor capable of realizing the epoxidation reaction.

[0112] Evaporator 6 is connected to the reactant outlet of epoxidation reactor 5. Evaporator 6 is used to separate the gas and liquid reactants after epoxidation to obtain a gaseous TBA / TBHP mixture with high TBHP content and a liquid mixture with high BM content.

[0113] Evaporator 6 includes an inlet and several outlets. The inlet is connected to the reactant outlet of epoxidation reactor 5, for example, through a pipe. The outlets are located at different positions on evaporator 6, specifically at different heights on evaporator 6. The composition (fraction) of the substance at different heights on evaporator 6 is different. The number and location of the outlets are set according to actual needs. In this embodiment, two outlets are provided, one of which is located at the top of evaporator 6 (for exporting the gaseous TBA / TBHP mixture with high TBHP content), and the other outlet is located at the bottom of evaporator 6 (for exporting the liquid mixture with high BM content).

[0114] The evaporator is selected according to actual needs and can be a conventional evaporator in the field, such as a falling film evaporator.

[0115] Stripping tower 7 is connected to evaporator 6 and is used to strip liquid mixtures with high BM content, separating BM from gaseous TBHP and / or TBA in the liquid mixture; stripping tower 7 is also connected to concentration tower 4, which is used to concentrate gaseous TBHP and / or TBA to obtain TBA vapor and liquid TBHP, and the liquid TBHP is introduced into epoxidation reactor 5 as raw material for recycling.

[0116] The stripping tower 7 includes at least two inlets and at least one outlet. One inlet is connected to the outlet at the bottom of the evaporator 6 and is located at the top of the stripping tower 7. This inlet is used to introduce a liquid mixture with a high BM content into the evaporator 6. The other inlet is located at the bottom of the stripping tower 7 and is used to introduce gaseous TBA gas. One outlet is used to discharge the separated crude epoxidized soybean oil and is located at the bottom of the stripping tower 7. In this embodiment, the stripping tower 7 also includes a gas outlet located at the top for discharging gas containing TBHP. The stripping tower 7 can be selected according to actual needs and can be a conventional stripping tower 7 in the art. In this embodiment, the theoretical number of stages of the stripping tower 7 is 5 to 20, preferably 7 to 15.

[0117] A concentration tower 4 is used to recover, purify, and concentrate a gaseous TBA / TBHP mixture with low TBHP content. The concentration tower 4 includes at least one inlet and at least one outlet. It is used to concentrate the gas containing TBHP and introduce the concentrated material as raw material into the epoxidation reactor 5. The number of inlets and outlets on the concentration tower 4 can be set according to actual needs, and can be one or more. In this embodiment, the concentration tower 4 also includes a reboiler, a condenser, and a reflux tank. The reboiler is located at the bottom of the concentration tower, and the condenser and reflux tank are located at the top. The concentration tower 4 includes two inlets: one inlet is connected to the outlet of the evaporator located at the top, and the other inlet is connected to the outlet at the top of the stripping tower. The concentration tower 4 includes two outlets: one outlet is located at the top of the concentration tower 4, and after the gas phase flows out, it splits into two paths; one path directly collects the TBA product, and the other path connects to the stripping tower 7, introducing the gaseous TBA gas into the stripping tower 7. One outlet at the bottom of the concentration tower 4 is connected to the inlet of the epoxidation reactor 5, used to introduce the concentrated TBA / TBHP into the epoxidation reactor 5.

[0118] A purge liquid is also provided in the passage connecting the concentration tower 4 and the epoxidation reactor 5 to balance the accumulated amount of impurities in the system. The concentration tower 4 is a conventional distillation tower. In this embodiment, the theoretical number of stages of the concentration tower is 10 to 25, preferably 15 to 20.

[0119] Example 2

[0120] Fresh isobutane at a rate of 535.58 kg / hr in pipe 11 and recovered isobutane at a rate of 572.00 kg / hr in pipe 32 are mixed and then dissolved with oxygen at a rate of 216.72 kg / hr in pipe 12 before entering peroxidation reactor 1. Simultaneously, ethylene glycol molybdenum solution at a rate of 4.41 kg / hr is introduced into peroxidation reactor 1 through pipe 13. The reaction temperature in peroxidation reactor 1 is 137°C, the pressure is 3.10 MPa, and the reaction residence time is 6 hr. The oxidation products are transferred to neutralization and deacidification unit 2 via pipe 14 at a rate of 1328.71 kg / hr. The oxidation products contain 42.87 wt% isobutane, 9.92 wt% TBHP, 37.36 wt% TBA, 1.67 wt% acid value (based on acetic acid), and 2.19 wt% moisture, and are designated as the first mixed system.

[0121] The 30% NaOH solution (44.53 kg / hr) in pipeline 21 and the first mixed system in pipeline 14 are neutralized in the mixer of the deacidifier 2 and then enter the middle section of the neutralization and deacidification tower. The demineralized water (15.59 kg / hr) at the top of the tower enters the upper section of the neutralization tower via pipeline. The tower temperature is 55℃ and the top pressure is 0.65 MPa. The first mixed system after water washing enters the isobutane recovery unit 3 from the top of the tower via pipeline 22. The isobutane content is 42.87 wt%, TBHP content is 9.92 wt%, TBA content is 37.36 wt%, acid value is 0.09 wt% (based on acetic acid), water content is 2.25 wt%, and Na... + The concentration was 1.3 ppm, and the brine phase after neutralization and washing was extracted from the bottom of the column at a rate of 88.05 kg / hr.

[0122] The first mixed system after neutralization and washing enters the isobutane recovery tower 3 at a rate of 1300.78 kg / hr. The isobutane recovery tower 3 is an isobutane removal tower with a top temperature of -21℃ and a top pressure of -0.03 MPa. The collected isobutane is circulated to the peroxidation reactor 1 for recovery and reuse at a rate of 572.00 kg / hr via pipeline 32. The bottom temperature of the isobutane recovery tower 3 is 75℃ and the bottom pressure is -0.01 MPa. The TBHP / TBA solution after isobutane removal is collected from the bottom at a rate of 728.78 kg / hr and sent to the TBHP concentration tower 4 via pipeline 31. The TBHP / TBA solution contains 18.26 wt% TBHP, 66.70 wt% TBA, 0.19 wt% acid value (based on acetic acid), and 3.97 wt% water.

[0123] The TBA gaseous stream from epoxidation reactor 5, at a flow rate of 510.94 kg / hr, enters concentration tower 4 along with the TBHP / TBA material from pipeline 31 via pipeline 53. The bottom temperature of concentration tower 4 is 77°C, the pressure at the top is -0.07 MPa, the top temperature is 60.00°C, and the top pressure is -0.05 MPa. 802.55 kg / hr of TBA is collected from the top of the tower via pipeline 42, containing 88.67 wt% TBA, 5.21 wt% acetone, and 3.56 wt% water. A qualified TBHP / TBA solution is collected from the bottom of the tower at a flow rate of 437.17 kg / hr, designated as the second mixed system. The second mixed system contains 54.99 wt% TBHP, 42.10 wt% TBA, 0.26 wt% water, and an acid value of 0.44 wt% (based on acetic acid).

[0124] A qualified TBHP / TBA solution enters the epoxidation reactor 5 at a flow rate of 435.72 kg / hr. It is mixed with soybean oil (291.79 kg / hr) from pipeline 51 and catalyst solution (11.23 kg / hr) from pipeline 52 via a mixer before entering the epoxidation reactor 5. The reaction temperature is controlled at 105–125°C, the reaction pressure at 0.02 MPa, and the reaction time at 60 min. During the reaction, the vaporized TBA vapor is collected and returned to the TBHP concentration tower 4 via pipeline 53 for reuse. Crude epoxidized soybean oil is collected from the epoxidation reactor 5 at a flow rate of 515.13 kg / hr. The crude epoxidized soybean oil contains 0.85 wt% soybean oil, 60.32 wt% epoxidized soybean oil, 22.56 wt% TBA, and 14.43 wt% TBHP.

[0125] Crude epoxidized soybean oil is distilled in evaporator 6, where 136.25 kg / hr of light components are flash-distilled at a pressure of -0.06 MPa, including 69.82% TBA and 28.19% TBHP. The liquid phase of the flash-distilled soybean oil and 110.77 kg / hr of TBA vapor are then fed into stripping tower 7 for further stripping of the remaining TBHP. The top pressure of stripping tower 7 is -0.09 MPa, the top temperature is 83°C, and the flow rate of the stripped vapor is 150.96 kg / hr, containing 75.99% TBA and 18.49% TBHP. The vapor from the top of the tower, along with the vapor from evaporator 6, is also fed into the TBHP concentration and refining unit via pipeline 53 for further TBHP recovery.

[0126] After simple water washing, the liquid phase in the bottom of stripping tower 7 yielded a pale yellow epoxidized soybean oil product with a yield of 325.45 kg / hr, an iodine value of less than 3.5, and an epoxy value of greater than 6.38.

[0127] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An apparatus for preparing epoxidized soybean oil by isobutane co-oxidation, characterized in that, The device includes: An oxidation reactor, wherein the oxidation reactor is used to provide space and environment for the oxidation reaction of a first reactant, the oxidation reactor including a feed inlet and an outlet; the first reactant includes isobutane, oxygen and a catalyst; An acid remover, which is connected to the peroxidation reactor, is used to neutralize acidic substances in the reaction products; An isobutane recovery tower is connected to an acid remover to recover isobutane from the reaction products after acid removal, and to introduce the recovered isobutane as a reaction feedstock into a peroxidation reactor. A concentration tower, connected to an isobutane recovery tower, is used to concentrate the TBHP / TBA solution after isobutane removal; An epoxidation reactor is provided to provide space and environment for the epoxidation reaction of a second reactant. The epoxidation reactor includes a feed inlet and a reactant outlet. The second reactant includes TBA, TBHP, and soybean oil. The epoxidation reactor is connected to a concentration tower to introduce a concentrated TBHP / TBA solution from the concentration tower as a reactant into the epoxidation reactor. An evaporator is connected to the reactant outlet of the epoxidation reactor. The evaporator is used to perform gas-liquid separation on the reactants after the epoxidation reaction to obtain a gaseous TBA / TBHP mixture with high TBHP content and a liquid mixture with high BM content. A stripping tower, connected to an evaporator, is used to strip a liquid mixture with a high BM content, separating BM from gaseous TBHP and / or TBA in the liquid mixture; the stripping tower is also connected to a concentration tower, which is used to concentrate gaseous TBHP and / or TBA to obtain TBA vapor and liquid TBHP, and the liquid TBHP is introduced into the epoxidation reactor as a raw material for recycling.

2. The apparatus for preparing epoxidized soybean oil by isobutane co-oxidation according to claim 1, characterized in that, The deacidifier includes at least two inlets and at least two outlets, wherein one inlet is connected to the outlet of the peroxidation reactor for introducing the reaction products into the deacidifier, and the other inlet is connected to the outside for introducing an alkaline solution into the deacidifier. One outlet is used to discharge the neutralized brine, and the other outlet is used to discharge the reaction products after acid removal.

3. The apparatus for preparing epoxidized soybean oil by isobutane co-oxidation according to claim 1 or 2, characterized in that, The isobutane recovery tower includes at least one inlet and two outlets. The inlet is connected to the outlet in the deacidifier that discharges the reaction products. One outlet is connected to the concentration tower, and the other outlet is connected to the peroxidation reactor for introducing isobutane as a reaction feedstock into the peroxidation reactor.

4. The apparatus for preparing epoxidized soybean oil by isobutane co-oxidation according to claim 1 or 2, characterized in that, The concentration tower includes at least one inlet and at least one outlet.

5. The apparatus for preparing epoxidized soybean oil by isobutane co-oxidation according to claim 4, characterized in that, The concentration tower includes two outlets: one outlet is located at the top of the concentration tower, and the other outlet is located at the bottom of the concentration tower. After the gas phase flows out from the top outlet, it splits into two paths: one path directly extracts TBA product, and the other path is connected to the stripping tower to introduce gaseous TBA gas into the stripping tower. The outlet at the bottom connects to the inlet of the epoxidation reactor and is used to introduce the concentrated TBA / TBHP into the epoxidation reactor.

6. A method for preparing soybean oil by co-oxidation of isobutane, characterized in that, The method includes the following steps: 1) The first reaction feedstock, including isobutane, catalyst and oxygen, is added to the peroxidation reactor to carry out the peroxidation reaction and prepare a first mixed system containing tert-butyl hydrogen peroxide, tert-butanol and isobutane; 2) The first mixed system in step 1) is deacidified to obtain a second mixed system containing isobutane, tert-butyl hydroperoxide and tert-butanol; 3) After removing isobutane from the second mixture system in step 2), mix it with soybean oil and catalyst to obtain the second reaction raw material, and carry out the epoxidation reaction to prepare crude epoxidized soybean oil and TBA / TBHP vapor. 4) The crude epoxidized soybean oil extracted in step 3) is evaporated and separated to obtain gaseous and liquid products; 5) After the gaseous product separated by evaporation is added to the concentration tower for concentration and enrichment, a gaseous TBA and TBHP / TBA mixture is obtained. The TBHP / TBA mixture is then introduced into step 3) as a reaction raw material for the epoxidation reaction for recycling. 6) Add the evaporated liquid product to the stripping tower, and introduce TBA steam into the stripping tower to remove TBHP from the liquid product to form TBHP / TBA mixed steam, which is then introduced into the concentration tower. 7) After the TBHP / TBA mixed steam is concentrated in the concentration tower, TBA steam is taken out from the top of the concentration tower. A portion of the TBA steam is sent to the condenser in the concentration tower for steam reflux; the other portion is heated to form superheated steam and then fed into the stripping tower to remove TBHP from the liquid phase product.

7. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, In step 1), the catalyst is an organometallic molybdenum catalyst or an organometallic vanadium catalyst, and the amount of the catalyst added to the reaction system is 2~30 ppm.

8. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, In step 1), the temperature of the oxidation reaction is 120~140℃ and the pressure of the reaction is 2.6~4.0MPa.

9. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, Step 3) involves the following steps to remove isobutane from the second mixed system: introducing the second mixed system into an isobutane recovery tower to remove isobutane; The bottom temperature of the isobutane recovery tower for removing isobutane is 74~76℃, and the top temperature of the isobutane recovery tower is -21~-19℃; the top reflux ratio of the isobutane recovery tower is (0.5~1.5):

1.

10. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, In step 3), the molar ratio of soybean oil double bonds to TBHP is 1:1.5-2.

5.

11. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, In step 3), the reaction temperature of the epoxidation reaction is 85-120℃, and the reaction time is 60-90 min.

12. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, In step 4), the evaporation is flash evaporation, and the pressure of the flash evaporation tube is -0.05 to -0.09 MPa.

13. The method for preparing soybean oil by co-oxidation of isobutane according to claim 6, characterized in that, Step 6) The TBA steam used for stripping is either TBA steam recovered from TBHP concentration or TBA steam that has been further purified.

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