81 results about "Reactive distillation" patented technology

This application relates to a UV-3 ultraviolet absorber and its preparation method, belonging to the field of chemical synthesis technology. The preparation method employs a one-pot process, in which benzocaine reacts with triethyl orthoformate in xylene solvent. This step utilizes reactive distillation coupling control, continuously removing the generated alcohol distillate through a distillation separation device to promote reaction equilibrium shift, obtaining a xylene solution of the intermediate NET. Subsequently, the solution is heated to a reaction temperature of 135–145°C, and benzyl chloride is added dropwise for N-alkylation, while a tail gas absorption device absorbs byproduct gases. The reaction slurry is then cooled for crystallization, solid-liquid separation, and drying to obtain the UV-3 product. This invention simplifies the production process through a one-pot process, avoids the use of toxic DMF solvent, and solves the technical problem of raw material residues leading to subsequent side reactions in the one-pot process through reactive distillation coupling control, resulting in a final product with high purity and high yield.

The invention discloses a method for preparing 6N and above high-purity Nb2O5 by using a niobium oxalate precursor, belongs to the technical field of niobium pentoxide preparation, and solves the problems of low purity and high impurity content of Nb2O5 prepared by the existing method. The method comprises the following steps: mixing niobium oxalate with high-purity water to obtain a mixed solution; performing cold crystallization purification; separating niobium oxalate crystals from the mother liquor, washing and drying; the method comprises the following steps: putting niobium oxalate crystals into a crucible, putting the crucible into a vacuum reaction distillation furnace, sealing a system, vacuumizing to below 1Pa, carrying out inert gas replacement, and then carrying out stage heating and heat preservation; cooling to 800-900 DEG C, introducing high-purity oxygen into the system, and carrying out oxidation stabilization treatment at a constant temperature; after treatment, continuously cooling to 200 DEG C or below, and then naturally cooling to room temperature to obtain a high-purity Nb2O5 product. The Nb2O5 product prepared by the method disclosed by the invention is high in purity and low in impurity content.

The diphenyl carbonate reactive distillation system comprises a reactive distillation tower, a reflux pipeline, a tower top reflux tank, a first condenser, a methanol recovery system, a reflux pump, a side extraction pipeline, a side extraction pump, a buffer tank, a discharge pipeline, a tower bottom pump and a flash tank, a tower top liquid material of the reactive distillation tower enters a tower top reflux tank through a reflux pipeline, and a gas material enters a methanol recovery system after being condensed by a first condenser; controlling the reflux ratio, and refluxing the material in the tower top reflux tank; the reactive distillation column is provided with a height-adjustable side line extraction opening for extracting by-products such as anisole; and separating the reaction organisms through a flash tank to obtain diphenyl carbonate. The device integrates chemical reaction and rectification separation, methanol is separated from a material refluxed at the top of the tower, by-products such as anisole are extracted from a side line, the thermodynamic equilibrium of the reaction is broken, and the reaction is pushed to proceed in the positive direction, so that the conversion rate is increased, and meanwhile, a plurality of by-products are obtained; and the side line extraction position is adjustable, safe and convenient.

This invention discloses a method for producing 4-methyl-2-pentanone, which is implemented using a 4-methyl-2-pentanone production apparatus. The apparatus includes a reactive distillation column, a condenser connected to the top of the reactive distillation column, and a reboiler connected to the bottom of the column. The reactive distillation column has a rectification section, a reaction section, and a stripping section arranged sequentially from top to bottom. During operation, a catalyst is placed in the reaction section, and 4-methyl-2-pentanol is introduced into the reaction section. The temperature of the reaction section is controlled at 180–280°C. The gas phase produced by the reaction is condensed by the condenser to produce 4-methyl-2-pentanone. This production method features high conversion rate, stable product quality, and low energy consumption.

The utility model provides a tetramethyl ammonium bicarbonate preparation device with low energy consumption, which comprises a reactive distillation tower, a static mixer, a methanol removal tower and a methanol recovery tower, a gas phase discharge port of the methanol removal tower is connected with an inlet of a steam compressor, a first branch connected with an outlet of the steam compressor is connected with a gas inlet of the methanol recovery tower, and a second branch connected with an outlet of the steam compressor is connected with a gas outlet of the methanol recovery tower. A second branch connected with an outlet of the steam compressor is connected with the first return tank through a heating medium channel of the steam generator; a third branch connected with an outlet of the first reflux tank is connected with a feed port of the methanol recovery tower, and a fourth branch connected with the outlet of the first reflux tank is connected with a tower kettle of the methanol removal tower; after pure water exchanges heat through a refrigerant channel of the steam generator, steam is output, and the steam is input into a tower kettle of the methanol removal tower through a pipeline; and the methanol recovery tower is provided with a side extraction opening for extracting high-purity methanol. The device disclosed by the utility model is low in operation energy consumption, low in equipment investment and high in raw material utilization rate, and can be used for continuously preparing high-purity TMAB and recovering to obtain a high-purity methanol product.

The present invention relates to a process for preparing at least one alkali metal methoxide by reactive distillation in at least one reaction column. At the lower end of the reaction column(s), the respective alkali metal methoxide dissolved in methanol is withdrawn. The methanol / water mixture obtained at the top of the reaction column(s) is separated by distillation in a rectification column.The vapours obtained at the upper end of the rectification column are compressed in at least two stages and the energy of the vapours compressed in each case is advantageously transferred to bottoms and side streams of the rectification column. This allows particularly efficient use of the energy of the compressed vapours in the process according to the invention. In addition, the energy in the product stream of alkali metal methoxide which is obtained at the lower end of the reaction column(s) is advantageously transferred to the vapour streams from the rectification column, especially before these vapours are subjected to compression.The energy from the compressed vapour may additionally be used for operation of the reaction column(s) or for operation of a reaction column in which a process for transalcoholization of alkali metal alkoxides is performed.

This invention discloses a catalytic reactive distillation unit, apparatus, and method. The catalytic reactive distillation unit includes: a reaction mass transfer channel, the upper end of which receives low-temperature liquid-phase reactants flowing downwards, and the lower end of which receives high-temperature gas phase flowing upwards; the reaction mass transfer channel contains a catalyst layer and a packing layer, with the catalyst layer positioned above the packing layer, and a first space between them; and a rising gas bypass, located outside the reaction mass transfer channel and connected to the first space. The liquid-phase products after the catalytic reaction merge with the high-temperature gas phase in the packing layer and undergo gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components from the liquid-phase products into the rising gas bypass, completing mass transfer separation. This invention, through the setting of the rising gas bypass, not only increases the gas phase flow rate and effectively reduces the pressure drop within the reaction mass transfer channel, but also effectively solves the space occupation problem of the equipment. This invention can clean the blockage of the catalyst filter without additional power and can realize online replacement of the catalyst and / or packing.

This invention provides an intelligent control system and method for the production of tert-butane without catalytic reduction, belonging to the field of tert-butane production control. The intelligent control system includes a host computer and sensing and execution mechanisms electrically connected to the host computer. The sensing mechanisms include a TDLAS analyzer installed at the top outlet of the reactive distillation column, NIR analyzers installed at the tert-butanol inlet of the mixing preheater and the side outlet of the reactive distillation column, temperature sensors installed at the top, bottom, and side outlet of the reactive distillation column, flow meters installed at the feed inlet, top outlet, and reflux inlet of the reactive distillation column, and multiple pressure sensors spaced at equal intervals along the height of the reaction section. The execution mechanisms include electrically operated regulating valves installed at the feed inlet and reflux inlet of the reactive distillation column. The control system integrates multiple sensors and execution mechanisms, enabling closed-loop intelligent control of the entire process.

A method for controlling a reactive distillation column for effecting a transalcoholisation reaction, comprising feeding a metal methoxide into the reactive distillation column via a side feed; feeding a reactant alcohol into a lower part of the reactive distillation column; withdrawing methanol from the top of the reactive distillation column; and withdrawing a solution of a product metal alkoxide in the reactant alcohol from the bottom of the reactive distillation column; wherein the method comprises a process control scheme selected from: Scheme A: establishing a signal S1 which is responsive to a temperature in the rectifying section disposed above the feed of the metal methoxide; and manipulating in response to the signal S1 the feed amount of the reactant alcohol; Scheme B: establishing a signal S1 which is responsive to a temperature in the rectifying section disposed above the feed of the metal methoxide; and manipulating in response to the signal S1 the heat supplied to the bottom of the reactive distillation column. The invention also relates to a method for controlling a reactive distillation column for effecting a transalcoholisation reaction, comprising feeding a metal methoxide into the reactive distillation column via a side feed; feeding a reactant alcohol into a lower part of the reactive distillation column; causing an auxiliary alcohol to be present in the reactive distillation column; and optionally replenishing the auxiliary alcohol via a side feed located above the feed of the reactant alcohol and below the top of the column; withdrawing methanol from the top of the reactive distillation column; and withdrawing a solution of a product metal alkoxide in the reactant alcohol from the bottom of the reactive distillation column; wherein the method comprises a process control scheme selected from: Scheme C: establishing a signal S2 which is responsive to a temperature at a point located between the feed of the metal methoxide and the bottom of the reactive distillation column; and manipulating in response to the signal S2 the feed amount of the reactant alcohol; Scheme D: establishing a signal S2 which is responsive to a temperature at a point located between the feed of the metal methoxide and the bottom of the reactive distillation column; and manipulating in response to the signal S2 the heat supplied to the bottom of the reactive distillation column. The methods of the invention allow for improved controlling of a reactive distillation column for effecting a transalcoholisation reaction.

The invention relates to an electronic-grade acetic ether production method and device based on reactive distillation-dividing wall tower distillation reinforcement. The device is composed of a reactive distillation system, an alcohol ester recovery tower system, an acetic ether concentration system and an acetic ether refining dividing wall tower system. An esterification reactor of the reactive distillation system adopts strong acid ion exchange resin as a catalyst; the contents of acetic acid and ethanol in the acetic ether reaction liquid are controlled by feeding fresh ethanol and acetic acid in a reactive distillation system; and crude ethyl acetate from which water and ethanol are removed by the ethyl acetate concentration tower is subjected to light component removal and heavy component removal by an ethyl acetate refining dividing wall tower to obtain an electronic-grade ethyl acetate product. The product purity is extremely high and stable, the whole set of process is designed for obtaining electronic-grade products, the final product purity stably reaches 99.99% or above, and the requirements of the high-end electronic chemical market are met. A dividing wall tower technology is adopted, light component removal and heavy component removal processes are integrated in a single tower, the number of devices and the occupied area are reduced, and energy is saved by 20%-30% compared with a traditional process.

This invention discloses a continuous production process for ethyl methyl carbonate (EMC), belonging to the field of organic carbonate synthesis technology. It aims to solve the problems of low conversion rate, poor selectivity, difficulty in catalyst separation and recovery, high energy consumption, and difficulty in stably preparing electronic-grade products in traditional batch processes. This invention uses dimethyl carbonate and ethanol as raw materials, employing a continuous reactive distillation coupled with a multi-stage distillation integrated process. Under the action of a solid base catalyst, a continuous transesterification reaction is achieved, simultaneously completing the discharge of the target product, online catalyst circulation, continuous separation of light and heavy components, and product purification. By precisely controlling the raw material ratio, reaction temperature, pressure, reflux ratio, and residence time, the entire process can operate continuously and stably. This invention features strong process continuity, high ethanol conversion rate, high EMC selectivity and yield, recyclable catalyst, low energy and material consumption, and the obtained product purity can reach electronic grade. It is suitable for the production of lithium-ion battery electrolyte solvents and is easy to scale up industrially and manage continuously.

The application provides a system and method for photocatalytic production of tetrahydrocycloheptane based on reactive distillation, and relates to the technical field of catalytic chemistry. The system comprises a backpack reactive distillation device, a solvent recovery and product purification column, and multiple heat exchangers. The backpack reactive distillation device comprises a distillation column and N photo reactors connected with the distillation column. The raw material norbornadiene, the side sampling stream of the distillation column, and the circulating stream taken from the bottom of the solvent recovery and product purification column are respectively introduced into each photo reactor from three paths. The reflux stream of the distillation column and the outlet streams of the N photo reactors are introduced into the distillation column. The crude product taken from the bottom of the distillation column is introduced into the solvent recovery and product purification column, the solvent recovery and product purification column separates and purifies tetrahydrocycloheptane and recovers the solvent, and high-efficiency and high-purity preparation of tetrahydrocycloheptane is realized.

The embodiment of the invention provides a separation method and a separation device for ethylene glycol and 1, 2-butanediol. The method comprises the following steps: carrying out reactive distillation treatment on a to-be-separated system containing ethylene glycol and 1, 2-butanediol and isobutene to obtain an ethylene glycol mono-tert-butyl ether crude product light component and a 1, 2-butanediol crude product heavy component; carrying out first rectification treatment on the ethylene glycol mono-tert-butyl ether crude product light component to obtain a refined ethylene glycol mono-tert-butyl ether light component and an alcohol-containing mixture heavy component; carrying out second rectification treatment on the 1, 2-butanediol crude product heavy component to obtain an alcohol-containing mixture light component and a refined 1, 2-butanediol heavy component; and returning the alcohol-containing heavy component and the alcohol-containing mixture light component to participate in the reactive distillation treatment. According to the method, efficient separation of ethylene glycol and 1, 2-butanediol is realized, and high-valued resource utilization of by-products of a system to be separated is realized at the same time.

A method for producing a carbonate having an aryl group, said method comprising: a reaction distillation step in which a starting material containing a dialkyl carbonate and a hydroxyaryl compound is continuously supplied into a reaction distillation column (A) in which a transesterification reaction catalyst is present; reaction and distillation are simultaneously performed in the tower A, a fraction AU containing an alkyl alcohol and a dialkyl carbonate is continuously extracted from the upper part of the tower A, and a fraction AL containing a hydroxyaryl compound, an alkyl carbonate aryl ester and a diaryl carbonate is continuously extracted in a liquid form from the lower part of the tower A; an extraction distillation step in which an extraction agent having a hydroxyaryl compound as the main component is supplied from the upper part of an extraction distillation column (B), a mixture containing an alkyl alcohol and a dialkyl carbonate is supplied from the lower part of the column (B), extraction distillation is performed, a fraction (BU) having an alkyl alcohol as the main component is extracted from the upper part of the column (B), and the fraction (BU) is extracted from the lower part of the column (B). And withdrawing a fraction BL containing dialkyl carbonate and a hydroxyaryl compound from the lower part of the column B; and a supply step in which the fraction (BL) is continuously supplied to the tower (A).

Systems and methods for processing mixed plastic waste can include one or more reactive extruders for initially dechlorinating and depolymerizing the mixed plastic waste and a catalytic reactive distillation column for further processing the dechlorinated, depolymerized mixed plastic waste. Depolymerization of the mixed plastic waste by one or more of the disclosed systems and methods produces at least a naphtha mixed feedstock and increases its yield.

This invention provides a method and system for preparing ethylene glycol mono-tert-butyl ether, relating to the field of chemical synthesis technology. The method for preparing ethylene glycol mono-tert-butyl ether includes: in a plug flow reactor, ethylene glycol and isobutylene undergo an etherification reaction in the presence of a liquid acid catalyst to obtain a mixture one; the mixture one is subjected to azeotropic separation to obtain a mixture two containing ethylene glycol mono-tert-butyl ether and ethylene glycol di-tert-butyl ether; the mixture two is purified and separated to obtain ethylene glycol mono-tert-butyl ether and ethylene glycol di-tert-butyl ether respectively; the separated ethylene glycol di-tert-butyl ether is returned to the plug flow reactor so that the subsequent etherification reaction can be carried out in the presence of ethylene glycol di-tert-butyl ether. This invention utilizes a plug flow reactor reaction and reactive distillation technology, and employs a liquid acid catalyst to provide a high concentration of protons, reducing the activation energy of the reaction, thereby efficiently activating the reactant molecules and achieving the goal of efficiently producing ethylene glycol mono-tert-butyl ether.

The invention provides a system and a method for preparing oxalic acid by hydrolyzing dimethyl oxalate. The system comprises a pre-reaction kettle, a methanol tower, a hydrolysis tower, a methanol tower condenser, a mother liquor heat exchanger and a crystallization unit which are connected with one another through pipelines. The method comprises the following steps: feeding a mixed solution of fresh dimethyl oxalate and desalted water and a thermally coupled circulating mother solution into a pre-reaction kettle for primary hydrolysis reaction, then feeding into a methanol tower for reactive distillation, returning a tower bottom solution to a hydrolysis tower material for reactive distillation, and returning a gas phase at the top of the hydrolysis tower to the bottom of the methanol tower material for feeding, refined methanol is extracted from the top of the methanol tower, one stream of oxalic acid hydrolysate in the kettle of the hydrolysis tower is mixed with the mother liquor and enters the pre-reaction kettle, and the other stream of oxalic acid hydrolysate is thermally coupled with the mother liquor and then enters the crystallization unit to obtain refined oxalic acid. The dimethyl oxalate conversion rate is high, the methanol purity is high, the monomethyl oxalate content in the oxalic acid hydrolysate is low, oxalic acid crystallization and thermal coupling of the mother liquor and the hydrolysate are facilitated, and the overall energy consumption is reduced.

A process for preparing trioxane from methanol includes: step 1: subjecting a mixture of methanol and methylal to a reaction to obtain formaldehyde, and absorbing the formaldehyde with water to obtain a concentrated formaldehyde aqueous solution; step 2: subjecting the concentrated formaldehyde aqueous solution to cyclization to obtain a mixture containing trioxane, and passing the mixture through a trioxane concentration tower to obtain a crude trioxane product; step 3: converting a by-product and unreacted formaldehyde in the crude trioxane product into methanol, conducting dehydration through a membrane dehydration process, and subjecting a retentate to dealcoholization to obtain purified trioxane; and step 4: subjecting the remaining streams to reactive distillation to obtain a mixture of methanol and methylal at a top- and water at a bottom of the reactive distillation tower; returning the mixture of methanol and methylal to step 1; and returning or discharging the water.

The invention provides an ethylene glycol purification method and an ethylene glycol purification device. The method comprises the following steps: carrying out reactive distillation treatment on a to-be-purified system containing ethylene glycol and 1, 2-butanediol and ethylene carbonate to obtain an ethylene glycol crude product light component and a carbonate heavy component; carrying out ethylene glycol rectification treatment on the ethylene glycol crude product light component to obtain a refined ethylene glycol heavy component and an unreacted to-be-purified system; returning the unreacted to-be-purified system to carry out the reactive distillation treatment; carrying out carbonate rectification treatment on the carbonate heavy component to obtain a refined butylene carbonate light component and an ethylene carbonate crude product heavy component; performing crystallization treatment on the heavy component of the ethylene carbonate crude product to obtain refined ethylene carbonate and mother liquor rich in butylene carbonate; wherein part of the refined ethylene carbonate is returned to participate in the reactive distillation treatment. According to the method, efficient purification of ethylene glycol is realized, internal circulation of ethylene carbonate is formed, and a high-purity carbonate product is obtained.

This invention provides a method for synthesizing carboxylic acid esters, belonging to the field of organic synthesis. The synthesis method of this invention includes the following steps: mixing a fatty alcohol and / or alcohol ether, a fatty acid, and p-toluenesulfonate for an esterification pre-reaction to obtain a pre-reaction system containing dissolved p-toluenesulfonate; the pre-reaction system contains a portion of the carboxylic acid ester, unreacted fatty alcohol and / or alcohol ether, fatty acid, and a portion of byproduct water; mixing the pre-reaction system with an azeotropic dehydrating agent for a reactive distillation esterification reaction, separating the byproduct water, and obtaining the carboxylic acid ester. This invention uses p-toluenesulfonate as a catalyst for the esterification pre-reaction to obtain a pre-reaction system containing dissolved p-toluenesulfonate. During the reactive distillation esterification reaction, the reaction system is homogeneous. After the reaction, it can be separated, recovered, and recycled, exhibiting good selectivity and minimal corrosion to the reactor. Through the esterification pre-reaction and reactive distillation esterification reaction, the reaction time can be shortened and energy consumption reduced.

Disclosed herein are various embodiments pertaining to continuous processes for making ethylene glycol diacetate, also known as 1,2-diacetoxyethane, by esterification of monoethylene glycol to 2-hydroxyethyl acetate and the esterification of 2-hydroxyethyl acetate to ethylene glycol diacetate. Various embodiments herein use reactive distillation in processes promising enhanced economic viability in the production of high-quality ethylene glycol diacetate.

The application discloses a kind of broken agent online recovery unit and the reaction rectifying tower of the unit of application unit, broken agent online recovery unit is suitable for gas-liquid-solid reaction in reaction rectifying tower, including: broken material receiving tray, it is located above liquid level and is set in the inner wall of reaction rectifying tower;Circulation guide rail, starting point is located above broken material receiving tray and extends along the inner wall of tower, middle section of guide rail is below liquid level, and guide rail end point is the same as starting point to form closed loop;Basket, it moves along circulation guide rail and collects broken catalyst and / or filler solid particles in liquid phase by the double-aperture screen structure arranged in basket, and basket after broken material collection returns to guide rail end point above liquid level along circulation guide rail and unloads broken material to broken material receiving tray.The application can recover broken solid particles on line and supplement equivalent fresh catalyst or filler particles on line, avoid affecting gas-liquid mass transfer efficiency and reaction rate in tower.

Methods for processing a crude oil feedstock include introducing a crude oil stream to a reactive distillation unit to remove conradson carbon and metals from the crude oil stream and generate a distillate stream having a mean boiling point distribution less than the crude oil stream and passing the distillate stream in a gaseous form in a continuous manner and without further processing to a catalytic cracking reactor that cracks the distillate stream to form a petrochemical product stream including light olefins and BTX. The catalytic cracking reactor includes a cracking catalyst and a susceptor material dispersed throughout the catalytic cracking reactor. Further, the catalytic cracking reactor operates at a temperature of 300° C. to 800° C. with heating from magnetic induction of the susceptor material.

The application relates to the chemical technology field and discloses a diphenyl carbonate reaction rectification production method based on overhead side line produced heat integration. The method is configured with a reaction rectification tower and a flash separation tank, a high-temperature side line liquid phase is led out from the lower part of a rectification section or the upper part of a reaction section, mixed with fresh methyl phenyl carbonate raw materials, mixed fluid is adiabatically flashed in the flash tank to realize phase state reconstruction, separated gas phase is bypassed and transported to the bottom of the rectification section to quickly remove by-product dimethyl carbonate, and liquid phase is transported to the top of the reaction section to enrich methyl phenyl carbonate reactants. The application realizes dynamic and accurate control of the gas-liquid ratio and heat content state of the tower by constructing the pressure gradient between the devices and adjusting the side line circulation ratio. The method reduces the preheating energy consumption of raw materials by using side line sensible heat, breaks the reaction balance limitation by cooperating with gas-liquid double track staged feeding, and improves the diphenyl carbonate reaction conversion rate and the whole system operation stability.

The invention belongs to the technical field of chemical processes, and particularly relates to a method for continuously synthesizing pyruvic acid through catalytic oxidation of ethyl lactate and coupled reaction rectification. According to the method, ethyl lactate and hydrogen peroxide are used as raw materials, a titanium silicalite molecular sieve is used as a catalyst, pyridine-2-formic acid is added as an auxiliary agent, ethyl pyruvate is synthesized in a tubular reactor filled with the catalyst, then under the condition of reduced pressure, pyruvate is hydrolyzed through a continuous reactive distillation tower, and a pyruvic acid water solution is obtained at the tower bottom. According to the invention, a tubular reactor model is adopted, the side reaction of hydrogen peroxide caused by backmixing of kettle reaction is solved, meanwhile, pyridine-2-formic acid is added as an auxiliary agent, the invalid decomposition of hydrogen peroxide in the catalytic oxidation process is solved, and the utilization rate of hydrogen peroxide is improved. Reaction rectification is coupled in the ethyl pyruvate hydrolysis process, continuous hydrolysis of ethyl pyruvate is achieved, a reaction section is filled with styrene resin with sulfonic acid groups to catalyze hydrolysis of ester, the reaction rate is increased from the thermodynamic angle, ethyl alcohol is promoted to be moved out of a system in the decompression hydrolysis kinetics, the reaction time is greatly shortened, and the yield is increased. And high-efficiency, continuous and green synthesis of pyruvic acid is realized.

The invention provides a reactive distillation tower which comprises a tower body extending in the vertical direction, and a reboiler and a condenser are arranged at the two ends of the tower body respectively; the reaction section is positioned between the stripping section and the rectifying section and comprises a heat exchange device and a push-pull frame; the heat exchange device is connected with the reboiler; the push-pull frame is mounted on the tower body in a sliding manner; an inlet / outlet is formed in the side wall of the tower body, and a limiting sealing mechanism is arranged in the tower body; the limiting sealing mechanism comprises baffles located on the two sides of the push-pull frame and a top plate located above the push-pull frame. One end of the top plate is provided with an abutting part which is bent downwards; one end of the push-pull frame is provided with a butt joint plate corresponding to the butt joint part; the butt joint plate is located on the side, relatively close to the heat exchange device, of the abutting part. The catalyst is mounted on the push-pull frame, so that the catalyst can be replaced when the push-pull frame slides out; after the push-pull frame slides out by a certain displacement, the end butt joint plate can abut against the top plate, the space where the push-pull frame is located can be independent of the internal space of the tower body through cooperation with the baffle, and catalyst replacement without shutdown is achieved.

The present application provides a method for purifying triethylamine by reactive distillation. The method is: carrying out reactive distillation of crude triethylamine with a reactive entrainer and a catalyst in a reactive distillation column; the reactive entrainer is selected from a compound containing a labile carbonyl group and / or a compound containing a sulfonyl group, and the catalyst is selected from an azaheterocyclic compound and / or an organic amine compound. In the present application, one molecule of the reactive entrainer can react with four molecules of various impurities, and the high-efficiency catalyst greatly improves the impurity removal efficiency. At the same time, the high-efficiency continuous reactive distillation can solve the high energy consumption problem caused by the need for distillation to recover the extractant in the traditional extractive distillation purification.

This invention relates to a method and apparatus for separating methanol and dimethyl carbonate products from transesterification. By introducing a reactive distillation column heat pump and a low-pressure separation column steam heat pump into the process, steam consumption can be significantly reduced by more than 33% compared with the process without the introduction of heat pumps.

The invention provides a method for preparing alkenyl ester containing double bonds through continuous reactive distillation, which comprises the following steps: S1) mixing carboxylic acid containing alkenyl and a polymerization inhibitor to obtain a raw material mixed solution; s2) feeding the raw material mixed solution from the upper part of continuous reaction rectification equipment, feeding alcohol steam from the lower part of the continuous reaction rectification equipment, and enabling the raw material mixed solution to flow from top to bottom to react with the alcohol steam under the action of a supported acidic solid catalyst; and S3) sequentially carrying out alkali washing and water washing on the crude ester obtained by the reaction, and then refining to obtain alkenyl ester containing double bonds. The invention further provides a system for preparing alkenyl ester containing double bonds through continuous reactive distillation. According to the method for preparing the alkenyl ester containing the double bonds through continuous reactive distillation, the reaction efficiency of the alkenyl-containing carboxylic acid and the purity of the alkenyl ester containing the double bonds are improved.

The present invention relates to an integrated method for simultaneously preparing at least two mixtures comprising alkali metal methoxides and methanol in at least two parallel reactive distillation columns, wherein a methanol feed stream is provided using a rectification column, which is subsequently used as a methanol source for the reactive distillation column, and wherein the overhead feed stream of the reactive distillation column is used as a methanol source for the rectification column.