CN115814717A - Continuous acidolysis circulating reactor and ethephon preparation method - Google Patents

Abstract

The application provides a continuous acidolysis circulating reactor, which comprises a reaction kettle, a Venturi part, a liquid circulating system and a gas separation-circulating system, wherein the liquid circulating system comprises at least one heat exchanger and at least one circulating pump, and the liquid circulating system is communicated with a liquid outlet of the reaction kettle and a Venturi nozzle fluid; the gas separation-recycle system includes a condenser and a receiver, the gas separation-recycle system being in fluid communication with the gas outlet and the gas inlet of the reaction vessel. The present application also provides a process for the continuous gas-liquid two-phase reaction in said reactor, in particular for the synthesis of ethephon by acidolysis, comprising the circulation of gas and liquid phase materials by means of said liquid circulation system and gas separation-circulation system. By adopting the reactor and the method, the excellent reaction performance is realized, meanwhile, the reaction equipment can run in a continuous mode, the production efficiency and the raw material utilization rate are obviously improved, and the effective service life of each part in the reactor can be effectively prolonged.

Description

Continuous acidolysis circulating reactor and ethephon preparation method

Technical Field

The present application relates to the field of chemical engineering, and more particularly to a loop reactor suitable for carrying out acidolysis reactions in a continuous manner and a method for preparing ethephon using the same.

Background

How to perform a smooth gas-liquid phase reaction in a reactor system having a simple structure in a continuous process with high efficiency has been a problem faced by those skilled in the chemical industry. Such as the acid hydrolysis synthesis of ethephon is a typical example.

Ethephon is known to have plant growth regulating effects and can be used in the form of an aqueous solution to provide functions of promoting seed germination, flowering and fruiting, fruit ripening, and the like of crops. In addition, when people cut rubber from rubber trees, ethephon is also adopted to stimulate the cut of the rubber trees, so that the flow of natural latex is increased. Ethephon has a wide application prospect and an increasing demand in the above-mentioned fields.

The chemical synthesis of ethephon at present includes a reaction of subjecting 2-chloroethyl bis (2-chloroethyl) phosphate (hereinafter referred to as "n-ester") to a gas-liquid phase/acid hydrolysis reaction with hydrogen chloride gas to generate ethephon, and fig. 1 shows the mechanism of the reaction.

The above-mentioned gas-liquid phase reaction is initially carried out in a conventional tank reactor, but this inevitably results in the defects of poor gas-liquid mass transfer, non-uniform reaction, poor reaction efficiency, poor heat transfer control and the like in the reaction tank, and in addition, under the poor conditions of heat transfer and mass transfer, the local high temperature also easily causes the rapid corrosion of the components such as a pump and a compressor in the reactor by the hydrogen chloride, and the above-mentioned problems all bring about significant adverse effects on the industrial mass production of ethephon.

In order to overcome the above problems in the prior art, a great deal of research has been conducted in an attempt to improve the structural design of the reactor and the process steps. For example, reported improvements include feeding the gaseous feed from the bottom of the reactor, attempting to improve heat and mass transfer within the reactor by gas sparging; there is also reported an improvement in that a plurality of tank reactors are connected in series so that the reaction materials are passed through the plurality of reaction tanks in order to expect an improvement in the reaction efficiency thereby. Unfortunately, these prior art efforts have resulted in only a limited degree of mass and heat transfer improvement, and the above-mentioned technical drawbacks remain to varying degrees. Therefore, all the technical difficulties mentioned above still exist in the prior art.

Therefore, there is still a great need in the art to develop an improved and unique solution that significantly improves the mixing uniformity and heat and mass transfer in the reactor with a simple and low cost design to significantly improve the reaction efficiency, and also to use as low a temperature as possible in each of the components of the process to mitigate the acid corrosion of the reactor components by hydrogen chloride under high temperature conditions.

Disclosure of Invention

In view of the above problems, the inventors of the present application have conducted intensive studies to successfully develop a continuous acidolysis circulating reactor and a method for preparing ethephon by using the same to perform a continuous reaction, thereby effectively solving the problems that have been urgently solved in the prior art, and the reactor and the method of the present invention can also be used to perform other gas-liquid phase reactions having similar requirements.

A first aspect of the present application provides a continuous acidolysis circulating reactor comprising a reaction vessel, a venturi section, a liquid circulation system and a gas separation-circulation system, the reaction vessel comprising a liquid outlet at its bottom, a gas inlet, a liquid inlet and a gas outlet at its top; the venturi part is a tubular part and comprises a venturi nozzle, a mixing section and a diffusion section from top to bottom, the lower part of the venturi part is inserted into the reaction kettle, and the upper part of the venturi part protrudes from the top of the reaction kettle; the liquid circulation system comprises at least one heat exchanger and at least one circulating pump, and is in fluid communication with the liquid outlet of the reaction kettle and the venturi nozzle; the gas separation-recycle system includes a condenser and a receiver, the gas separation-recycle system being in fluid communication with the gas outlet and the gas inlet of the reaction vessel.

A first aspect of the present application provides a process for the continuous gas-liquid biphasic reaction, more particularly for the acidolysis synthesis of ethephon in a continuous manner, carried out in a reactor according to the present application, comprising: adding at least one gas-phase reactant into the reaction kettle through the gas inlet, and adding at least one liquid reactant into the reaction kettle through the liquid inlet, wherein the at least one gas-phase reactant and the at least one liquid reactant react in the reaction kettle to generate a liquid-phase product; introducing at least a portion of the liquid phase material in the reaction vessel into a liquid circulation system, harvesting at least a portion of the liquid phase product, and circulating the remaining liquid phase material at least partially through a venturi section back into the reaction vessel; at least a portion of the gas phase feed within the reaction vessel is introduced into the gas separation-recycle system, at least a portion of the gas phase by-product is separated and collected in a receiver, and the remaining gas phase feed is recycled at least partially back to the reaction vessel through the venturi assembly.

Drawings

Various embodiments of the present application are discussed in the following paragraphs in conjunction with the figures. It is to be noted, however, that the embodiments illustrated in the drawings and described in the following detailed description are only preferred embodiments of the present application, and the scope of the present application is defined by the appended claims rather than being limited to the preferred embodiments. In addition, the reactor and various components shown in the figures of the specification are not necessarily drawn to true scale for the sake of clarity.

FIG. 1 shows the mechanism by which bis (2-chloroethyl) 2-chloroethyl phosphate reacts with hydrogen chloride gas to form ethephon;

FIG. 2 shows an exemplary configuration of a reaction vessel in a reactor of the present application, according to one embodiment of the present application;

FIG. 3 shows a schematic diagram of a reactor of the present application, according to an exemplary embodiment of the present application.

Detailed Description

The "ranges" disclosed herein are in the form of lower and upper limits. There may be one or more lower limits, and one or more upper limits, respectively. The given range is defined by the selection of a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this manner are inclusive and combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for particular parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3,4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers.

In the present application, all embodiments and preferred embodiments mentioned herein may be combined with each other to form new solutions, if not specifically stated.

In the present application, all the technical features mentioned herein as well as preferred features may be combined with each other to form new technical solutions, if not specifically stated.

In the present application, the term "comprising" as used herein means either an open type or a closed type unless otherwise specified. For example, the term "comprising" may mean that other components not listed may also be included, or that only listed components may be included.

In this application, when a device or component is described as being "in fluid communication" with another device or component, it is meant that the two are in direct or indirect communication via one or more means or devices such that a fluid (e.g., a gas, a liquid, or a mixture thereof, etc.) has the ability to flow between the two, but "in fluid communication" does not necessarily mean that a fluid may flow between the two at any time, and such as a switch, valve, flow guide, etc. may be provided between the two to temporarily block flow between the two as desired.

The reactor of the present application can be used for performing gas-liquid phase reactions between various gas phase reactants and liquid phase reactants, and the reactor structure and process condition design of the present application are mainly described in the specification of the present application by taking the gas-liquid phase/acid hydrolysis reaction of 2-chloroethyl bis (2-chloroethyl) phosphate (hereinafter referred to as "n-ester") with hydrogen chloride gas as an example, and the ethephon-generating reaction as an example, but the reactor and method of the present application can also be used for reactions between various other gas phase reactants and liquid phase reactants, particularly for reactions that generate a large amount of heat release and have large acidity, alkalinity or corrosiveness of reaction raw materials, products and/or by-products, and similar technical effects can be obtained based on the reactor and method of the present application. Non-limiting examples of such other gas-liquid phase reactions may include acid hydrolysis of various esters, halogenation of various organic compounds, and the like.

The reactor of the present application is a reactor capable of carrying out a reaction in a continuous manner, and includes a reaction vessel including a liquid outlet at the bottom thereof, a gas inlet, a liquid inlet, and a gas outlet at the top thereof, a venturi section, a liquid circulation system, and a gas separation-circulation system.

FIG. 2 shows a schematic of a reaction vessel and a venturi section included in a reactor according to one embodiment of the present application. The reaction kettle is provided with a sealed kettle body, a liquid outlet is arranged at the bottom of the reaction kettle, a gas inlet, a liquid inlet and a gas outlet are arranged at the top of the reaction kettle, a Venturi part is inserted into the reaction kettle from the top of the reaction kettle, the gas inlet is used for introducing a gas-phase reactant into the reaction kettle, the liquid inlet is used for introducing a liquid-phase reactant into the reaction kettle, the gas outlet is used for leading out at least one part of gas-phase material from the reaction kettle in the continuous reaction process and carrying out separation and circulation operation on the gas-phase material through a gas separation-circulation system, and the liquid circulation system is used for leading out at least one part of liquid-phase material from the reaction kettle in the continuous reaction process and carrying out extraction (harvesting) of liquid products and circulation operation on unreacted liquid-phase raw materials through a liquid circulation system. According to a separate embodiment of the present application, the liquid inlet and the gas inlet may be disposed at the top of the reaction vessel for introducing the liquid phase reactant and the gas phase reactant, respectively, into the reaction vessel. According to another independent embodiment of the application, at least one of the liquid inlet and the gas inlet may be provided at the nozzle of the venturi part, for example as a material inlet on the top of the venturi nozzle or on the side wall of the suction chamber outside the nozzle part of the venturi part. According to one embodiment of the application, the liquid inlet can be arranged at the nozzle of the venturi part, for example as a material inlet on the top of the nozzle of the venturi part or on the side wall of the suction chamber outside the nozzle. According to another embodiment of the application, the gas inlet can be arranged at the nozzle of the venturi part, for example as a material inlet on the side wall of the suction chamber outside the nozzle part of the venturi part. According to another embodiment of the application, both said liquid inlet and said gas inlet may be provided at the nozzle of the venturi member, for example as material inlets provided at the top of the nozzle of the venturi member or on the side wall of the suction chamber outside the nozzle.

According to one embodiment of the present application, as shown in FIG. 2, the venturi member includes, in order from top to bottom, a nozzle (venturi nozzle), a mixing section, and a diffuser section. The nozzle may have a truncated conical shape with a narrow top and a wide bottom, a suction chamber is provided outside the nozzle, and a small hole or slit is provided in an outer wall of the nozzle to be in fluid communication with the suction chamber. As the material (e.g. circulating liquid material) flowing from above the nozzle changes shape as it flows through the nozzle, it creates a negative pressure suction by the venturi effect on the material in the suction chamber (e.g. liquid or gaseous material as described above flowing from an inlet in the side wall of the suction chamber) drawing the material in the suction chamber into the nozzle, causing the material from the inlet in the side wall of the suction chamber to enter the nozzle with the material from the top of the venturi nozzle and flow downwardly into the mixing section below the nozzle.

The venturi member mixing section may have a cylindrical shape or a truncated conical shape, and the materials entering from the venturi nozzle tip and the suction chamber sidewall inlet are thoroughly mixed in the mixing section and then flow downward into the diffuser section. The diffuser section has a truncated conical shape, an upper portion of which is connected to a bottom portion of the mixing section, and a lower portion of which is inserted below a liquid level in the reaction vessel, so that the material (at least one of the circulating liquid-phase material, the circulating gas-phase material, the liquid-phase reaction raw material, and the gas-phase reaction raw material) from the nozzle is mixed in the mixing section and then enters the reaction material in the reaction vessel through the diffuser section. According to another embodiment of the present application, the liquid phase reaction feed may be added from a venturi section top nozzle.

In the embodiment shown in fig. 2, the top part (nozzle part) of the venturi part protrudes from the top of the reaction kettle, the middle part (approximately at the height of the mixing section) is fixed at the top of the reaction kettle, the joint of the venturi part and the reaction kettle is sealed by a sealing ring (a detachable fixed cover plate can be arranged here to facilitate the installation, replacement and routine maintenance and repair of the venturi part), the lower part (diffuser section) is positioned in the reaction kettle, and the bottom opening of the diffuser section is inserted below the liquid level in the reaction kettle all the time during the reaction process.

According to an embodiment of the application, control feeding volume and load reach the balance in the reaction process, maintain the height of liquid level in the reation kettle unchangeably, and the liquid commodity circulation or the gas-liquid mixture commodity circulation of high-speed injection from venturi part diffuser section can provide the stirring effect to the material in the reation kettle.

According to an embodiment of the present application, other various components, such as a stirring device (magnetic stirring device, mechanical stirrer, bubble stirrer, etc.), a temperature sensor, a pressure sensor, a sampling port, etc., may be further disposed on the reaction kettle as required. The outer side of the reaction kettle can be further provided with a heating jacket, such as an electric heating wire heating jacket or a heat conducting oil heating jacket, for controlling the temperature in the reaction kettle at a required level in the reaction process.

According to one embodiment of the present application, the reaction vessel, the venturi section, the liquid circulation system, and the gas separation-circulation system are each independently made of a material selected from the group consisting of: corrosion resistant metals, plastic materials, ceramic materials, silicon carbide materials, steel lined silicon carbide, steel lined plastics, steel lined glass and steel lined enamel, the plastics in the plastics and steel lined plastics may be, for example, polyethylene, polytetrafluoroethylene, and the like. For example, the reactor vessel may be made of steel lined enamel material and the pipes and circulation pump vanes in the fluid circulation system may be made of steel lined plastic (e.g. steel lined tetrafluoroethylene) material.

According to one embodiment of the present application, the liquid circulation system comprises at least one heat exchanger and at least one circulation pump, the liquid circulation system being in fluid communication with the liquid outlet at the bottom of the reaction vessel and the nozzle top inlet of the venturi device. According to a further embodiment of the present application, the liquid circulation device may comprise two or more heat exchangers and one, two or more circulation pumps, which circulation pumps are located downstream of at least one heat exchanger (front heat exchanger) and upstream of at least one further heat exchanger (rear heat exchanger). The heat exchanger may be any suitable heat exchanger known in the art, for example a heat exchanger using cooling water or heat transfer oil, preferably heat exchanger using heat transfer oil. According to a preferred embodiment of the present application, the liquid circulation system comprises two heat exchangers (one front heat exchanger and one rear heat exchanger) and one circulation pump. By arranging the circulation pump downstream of the at least one front heat exchanger, the circulation pump experiences a working temperature which is lower than the reaction temperature in the reaction vessel. According to one embodiment of the present application, the reaction temperature in the reaction vessel is maintained during the reaction at 120-160 ℃, such as 125-155 ℃, or 130-150 ℃, or 135-145 ℃, or 140-142 ℃, or within a range of values that can be obtained by combining any two of the above endpoints; and the temperature of the working temperature of the circulating pump in the liquid circulating system is equal to or lower than 120 ℃ in the working process, such as 80-120 ℃, or 90-120 ℃, or 100-115 ℃, or 110-115 ℃, or can be within the numerical range obtained by combining any two of the above values. Without wishing to be bound by any theory, since the circulation pump operates at the above-mentioned lower operating temperature, it is possible to effectively prevent the aging of the plastic lining (e.g., PTFE lining) used in the circulation pump and the separation thereof from the underlying steel substrate, thereby effectively extending the service life of the circulation pump, reducing the downtime for maintenance and repair of the reaction equipment, reducing the complexity of the process, and reducing the costs for operation and maintenance. According to one embodiment of the present application, the liquid stream flowing through the circulation pump is brought to a temperature of 120 ℃ or less as described above by using the front heat exchanger, and then the temperature of the liquid stream is raised to a temperature close to the temperature in the reaction vessel, such as ± 5 ℃ in the reaction vessel, for example, 125-165 ℃, or 130-150 ℃, or 135-140 ℃, or within a range of values that can be obtained by combining any two of the above endpoints with each other, while the liquid stream is flowing through the circulation pump and through the rear heat exchanger. According to another embodiment of the present application, the heat exchanger used in the present invention may be a shell-and-tube heat exchanger, such as a shell-and-tube heat exchanger with a tube side lined with silicon carbide, and the heat exchange fluid of the shell side may include cooling water, water vapor, heat transfer oil, etc., and may vary depending on the desired target temperature.

According to one embodiment of the present application, a liquid product outlet (also referred to as "take-off port") is provided in the liquid circulation system, for example, downstream of the circulation pump and upstream of the post heat exchanger, for taking off a portion of the liquid product (e.g., ethephon) in a continuous manner from the liquid stream flowing through the liquid circulation system.

According to another embodiment of the present application, one or more devices such as switches, valves, flow sensors, pressure sensors, temperature sensors, drain valves, connecting pipes, bypass pipes, and the like may be provided as needed upstream and downstream of the components (each heat exchanger and circulation pump) in the liquid circulation system. For example, if necessary, a drain valve may be provided upstream of the front heat exchanger and downstream of the circulation pump (but upstream of the rear heat exchanger), and during the continuous reaction, the drain valve may be opened as necessary to drain a part of the liquid phase stream for sampling analysis, product collection, waste disposal, or the like.

According to one embodiment of the present application, the continuous reactor of the present application further comprises a gas separation-recycle system comprising a condenser and a receiver, the gas separation-recycle system being in fluid communication with the gas outlet and the gas inlet of the reaction vessel. According to one embodiment of the application, the condenser comprises a top outlet connected to the receiver for receiving the by-product (for example dichloroethane) coming from the bottom of the condenser and a bottom outlet for separating mainly the unreacted gaseous reaction raw material and for recycling it at least partially back into the reaction vessel, for example to the nozzle of the venturi section, more particularly to the material inlet on the side wall of the suction chamber outside the nozzle section of the venturi section.

According to one embodiment of the present application, the condenser top outlet is further in fluid communication with a tail gas absorption device via a valve or switch, said tail gas absorption device being primarily used for collecting gaseous by-products and/or other gaseous materials in said gas separation-recycle system as desired, or for discharging a portion of the gaseous materials as desired to maintain a desired pressure and/or composition in the gas separation-recycle system.

According to another embodiment of the application, a back pressure valve is provided downstream of the condenser, for example the back pressure valve may be provided downstream of the condenser top outlet, more specifically between the condenser top outlet and the off-gas absorption device.

The back pressure valve used in the application is provided with a diaphragm and an internal spring, the action is realized through the elastic force of the internal spring, the starting pressure of the back pressure valve can be set, and when the gas pressure in the gas separation-circulation system is smaller than the set pressure, the diaphragm in the back pressure valve blocks a pipeline under the action of the elastic force of the spring; when the gas pressure in the gas separation-circulation system is higher than the set pressure of the back pressure valve, the diaphragm compresses the spring, the pipeline is communicated, and the gas in the gas separation-circulation system passes through the back pressure valve.

According to an embodiment of the present application, by using the back pressure valve, the gas pressure in the gas separation-circulation system can be effectively controlled while the off-gas discharge is effectively performed, thereby not causing any negative influence on the pressure in the reaction vessel (gas phase pressure) during the gas phase circulation. According to one embodiment of the present application, the pressure (gas phase pressure) in the reaction vessel may be maintained between 0.30 and 0.80MPa, such as between 0.40 and 0.70MPa, or between 0.50 and 0.60MPa, or may be maintained within a range of values obtained by combining any two of the above endpoints with each other; according to another embodiment of the present application, the gas pressure in the gas separation-recycle system is maintained at substantially the same level as the gas pressure in the reaction vessel by using a back pressure valve, for example, the gas pressure in the gas separation-recycle system is maintained at 0.40 to 0.70MPa, or 0.50 to 0.60MPa, or may be maintained within a range of values obtained by combining any two of the above-mentioned endpoints with each other.

According to another embodiment of the present application, one or more devices such as switches, valves, flow sensors, pressure sensors, temperature sensors, drain valves, connecting pipes, bypass pipes, and the like may be provided as required upstream and downstream of the respective components (condenser, backpressure valve, receiver) in the gas separation-circulation system. For example, a production switch and piping may be provided on the top, bottom, or side of the receiver as needed to produce the byproduct received in the receiver; a gas transfer line may also be installed at the top of the receiver to draw some of the gas phase feed (e.g., unreacted gas phase feed) to the receiver, to a tail gas absorber or to be combined with the gas phase effluent at the top outlet of the condenser before being recycled back to the reactor.

FIG. 3 illustrates a continuous acid hydrolysis circulation reactor according to one embodiment of the present application, in which a gas phase raw material tank (e.g., hydrogen chloride raw material tank) and a liquid phase raw material tank (e.g., normal ester raw material tank), a reaction vessel, a venturi section, a liquid circulation system, and a gas separation-circulation system are included in the reactor shown in FIG. 3, respectively. The parts are connected by pipelines, and one or more functional devices, such as switches, valves, flow meters, thermometers, pressure gauges, ports, pressure regulating devices, temperature regulating devices and the like, can be arranged in the pipelines according to requirements.

The structure of the venturi component is as described above, including nozzle, mixing section and diffuser, the suction chamber is arranged around the nozzle, the top (nozzle part) of the venturi component protrudes from the top of the reaction kettle, the middle part (approximately at the height of the mixing section) is fixed at the top of the reaction kettle, the joint of the venturi component and the reaction kettle is sealed by a sealing ring (a detachable fixed cover plate can be arranged at the joint of the venturi component and the reaction kettle, so as to facilitate the installation, replacement and daily maintenance and overhaul of the venturi component), the lower part (diffuser) is located inside the reaction kettle, and the bottom opening of the diffuser is always inserted below the liquid level in the reaction kettle in the reaction process. In the reactor shown in fig. 3, the inlet for the liquid-phase raw material is provided at the top of the reactor, not at the nozzle of the venturi section, and the inlet for the gas-phase raw material is provided at the nozzle of the venturi section (specifically, at the side wall of the suction chamber surrounding the venturi nozzle). Further, in the embodiment shown in FIG. 3, the gas outlet connected to the gas separation-circulation system is provided at the top of the reaction tank, and the gas-phase circulation material inlet after circulating in the gas separation-circulation system is provided at the nozzle of the venturi section (specifically, at the side wall of the suction chamber surrounding the venturi nozzle); the liquid outlet connected with the liquid circulating system is arranged at the bottom of the reaction kettle, and the inlet of the liquid-phase circulating material after circulating in the liquid circulating system is arranged at the top of the nozzle of the Venturi part, namely the circulating liquid-phase material is sprayed into the reaction kettle through the top of the nozzle of the Venturi part.

According to one embodiment of the present application, the reaction of a liquid feedstock (e.g. n-ester) and a gaseous feedstock (HCl) is carried out in the following manner. The liquid raw material is firstly input into the reaction kettle through a liquid inlet (the liquid inlet is positioned at the top of the reaction kettle or positioned at the top of a nozzle of a Venturi device) to reach a specific liquid level height, so that the bottom of the Venturi nozzle is always not below the liquid level in the whole reaction process. After the liquid raw material is added to the designated liquid level, the reaction kettle is closed, the reaction kettle is filled with the required atmosphere according to the requirement, for example, nitrogen is filled, then a valve at the tail gas absorption device is opened, the nitrogen in the reaction kettle is completely pumped out by using a vacuum pump, and then all the valves are closed to seal the reaction kettle. The gas raw material is charged into the reaction vessel through the gas raw material inlet so that the inside of the reaction vessel reaches a predetermined pressure, for example, 0.30 to 0.80MPa. The back pressure valve is set so that the pressure in the reaction vessel and the gas separation-circulation system is substantially the same, and for example, the pressure in both may be about 0.30 to 0.80MPa, or 0.40 to 0.70MPa, or 0.50 to 0.60MPa, or may be maintained within a range of values obtained by combining any two of the above-mentioned values with each other.

At this point, the feed of gaseous feed is temporarily stopped and the heating of the reactor is initiated, for example, by heating the temperature in the reactor to a temperature in the range of 120 to 160 deg.C, for example 125 to 155 deg.C, or 130 to 150 deg.C, or 135 to 145 deg.C, or 140 to 142 deg.C, or any combination thereof. Starting the liquid circulation system and the gas separation-circulation system, starting the front heat exchanger and the rear heat exchanger and the circulation pump in the liquid circulation system, for example, setting the temperature of the front heat exchanger to be equal to or lower than 120 ℃, for example, 80-120 ℃, or 90-120 ℃, or 100-115 ℃, or 110-115 ℃, or within a numerical range obtained by combining any two of the above endpoints; such that the temperature of the working temperature of the circulating pump is equal to or lower than 120 ℃, such as 80-120 ℃, or 90-120 ℃, or 100-115 ℃, or 110-115 ℃, or may be within a range of values obtained by combining any two of the above endpoints with each other; the temperature of the post heat exchanger is set to be substantially equivalent to the temperature in the reaction vessel, for example, the temperature of the reaction vessel is + -5 deg.C, such as 125-165 deg.C, or 130-150 deg.C, or 135-140 deg.C, or may be within a range of values obtained by combining any two of the above endpoints with each other. Through the arrangement, the liquid material in the reaction kettle is continuously led out from the bottom of the reaction kettle, is reduced to a lower temperature through the front heat exchanger, is re-heated to be basically equivalent to the temperature in the reaction kettle after flowing through the circulating pump, then enters the Venturi device from the top of the Venturi nozzle, and is sprayed below the liquid level in the reaction kettle through the Venturi device. During the circulation, the liquid stream is sampled from one or more liquid discharge ports in the liquid circulation system and the composition thereof is detected, and when the concentration of the target product in the liquid stream is confirmed to reach a desired level, the target product is obtained by discharging from the discharge port in a continuous manner, and simultaneously, the gas raw material and the liquid raw material are proportionally supplied into the reaction kettle in a continuous manner, so that the liquid level in the reaction kettle is kept constant. According to one embodiment of the application, the concentration of the target liquid product (e.g.ethephon) in the liquid feed continuously withdrawn here is 95% or more, such as 95-99.5%, or 95-99%, or 95-98%, or 95-97%, or 95-96%, the concentrations mentioned above being mass concentrations.

In addition, during the continuous reaction, the gas phase above the liquid level in the reaction vessel is introduced from the top of the reaction vessel and flows through the gas separation-circulation system. Specifically, the part of the circulating gas phase firstly passes through a condenser, the temperature of a refrigerant used by the condenser can be-16 ℃ to 30 ℃, the refrigerant used can be hydrocarbon refrigerant, ammonia water, condensed water or heat conduction oil, and a proper refrigerant can be selected according to the required target temperature. Condensing the vapor phase feed flowing through the condenser within the condenser to separate at least a portion of the by-product therefrom. For the reaction of n-esters and HCl, the by-products contained in the gas phase feed, which may include dichloroethane and small amounts of other halogenated hydrocarbons, etc., are condensed and then discharged from the bottom of the condenser and collected in a receiver. After the above condensation, the gaseous material flows out from the top of the condenser, the top outflow mainly contains unreacted gaseous raw material (such as hydrogen chloride gas), and the gaseous material is circulated to the venturi part, such as the top of the nozzle of the venturi part, or the circulating gas inlet of the side wall of the suction chamber arranged at the periphery of the nozzle of the venturi part. According to an embodiment of the application, still be provided with the tail gas absorbing device who links to each other with condenser top export be provided with the back pressure valve between condenser top export and the tail gas absorbing device, the structure of back pressure valve and set up the pressure as above. When the gas pressure experienced by the back pressure valve is greater than a set value, the back pressure valve is opened to perform exhaust gas emission so that the back pressure valve is automatically closed when the pressure in the gas separation-circulation system is reduced below a predetermined pressure, thereby maintaining the pressure in the gas separation-circulation system and the pressure in the reaction vessel at desired levels, which facilitates smooth and efficient reaction in the reactor and enables significant improvement in the conversion rate of reactants and the selectivity of products.

According to another embodiment of the present application, a gas transfer line is provided at the top of the receiver for withdrawing some of the gas phase feed (e.g., unreacted gas phase feed) that flows into the receiver, either to a tail gas absorber or to be combined with the gas phase effluent at the top outlet of the condenser before being recycled back to the reactor.

According to one embodiment of the present application, the liquid circulating material circulating in the liquid circulating system returns to the top of the nozzle of the venturi section and flows down through the nozzle into the reaction vessel below the liquid level. The liquid circulating material generates a negative pressure when flowing through the nozzle, thereby generating a suction force on the material flowing from the inlet of the side wall of the suction chamber, and the negative pressure can be-0.05 MPa to-0.1 MPa.

According to another embodiment of the present application, in the continuous reaction process, the liquid raw material and the gas raw material are continuously fed into the reaction vessel such that the liquid level in the reaction vessel is kept constant, and the pressure at which the liquid raw material is fed into the reaction vessel may be kept at 0.10 to 0.80MPa, for example, 0.20 to 0.70MPa, or 0.10 to 0.30MPa, or 0.40 to 0.60MPa, or may be within a range of values obtained by combining any two of the above-mentioned values with each other.

According to one embodiment of the present application, the liquid phase reactant (e.g. n-ester) and the gas phase reactant (e.g. hydrogen chloride gas) are fed into the reaction vessel in a continuous manner, and the molar ratio of the liquid phase reactant to the gas phase reactant is 1.0 to 1, such as 1.

According to one embodiment of the present application, the liquid phase reaction product is harvested in a continuous manner in the liquid circulation system, and the vapor phase reaction feed and the liquid phase reaction feed are replenished to the reactor in respective replenishment amounts while the liquid phase reaction product is harvested, such that the liquid level within the reactor remains constant after the newly replenished feed is mixed with the circulating vapor and liquid phase feed that is circulated back to the reactor through the venturi device. The product extraction amount and the fresh raw material supplement amount can ensure that the concentration (purity) of a target product (such as ethephon) in the extracted product is kept at a constant level, and the extraction amount of the product is increased as much as possible on the premise that the ethephon production capacity is maximized.

According to one embodiment of the present application, the continuous production of the gas-liquid phase reaction is achieved by the continuous production of the liquid phase product (e.g. ethephon), the gaseous phase by-product (e.g. dichloroethane) as described above, the recycling of the gaseous phase recycle according to the desired off-gas discharge (controlled by the pressure set by the back pressure valve), the recycling of the gaseous and liquid phase recycle, and the replenishment of the fresh gas feed and the fresh gas feed, maintaining a substantially constant liquid level and gas pressure in the reaction vessel. The conversion of the starting material (in terms of n-ester conversion) may be from 95 to 99%, such as from 95 to 98%, or from 95 to 97%, or from 95 to 96%, or may be within a range of values derived from any combination of any two of the foregoing endpoints. The purity of the product (n-ester) (i.e., the weight content of the desired product in the withdrawn liquid phase feed) may be 95% or more, e.g., 95-99.5%, or 95-99%, or 95-98%, or 95-97%, or 95-96%.

The reactor and process of the present invention may achieve one or more of the following advantages:

1. by combining the reaction kettle with the liquid circulation system and the gas separation-circulation system, the continuous production of product extraction, gas-liquid phase material circulation and fresh raw material supplement can be realized in an efficient manner, the excellent reaction performance, the reduction of the complexity of the reaction process, the improvement of the yield of the process per unit time are realized, the process is simple, the device is compact, the occupied area is small, the investment is low, the energy consumption is low, the utilization rate of the raw materials is high, the reaction rate is high, and the product quality is high;

2. the back pressure valve is utilized to improve the stabilization control of the pressure in the whole reaction system, eliminate the adverse effect of the pressure floating in the reaction system on the reaction and improve the reaction rate;

3. the high-efficiency separation of byproducts and the effective conveying of gas-phase circulating materials are realized, the forward movement of reaction balance is promoted, and the conversion rate, the utilization rate and the reaction conversion performance of raw materials are improved;

4. the efficiency of material mixing and reaction in the reactor is improved by adopting the Venturi device, and the reaction performance and the reaction rate are further improved;

5. through adopting special two heat exchanger designs in liquid circulation system, can make high temperature reaction keep apart with low temperature circulating pump work in the temperature, can improve the life of metal lining tetrafluoroethylene part in the circulating pump effectively, the liquid stream behind the circulating pump heats up again in the heat exchanger of back to the temperature that is suitable for and carries out the reaction in reation kettle, can not cause negative effects to the reaction of circulating liquid material in reation kettle, can carry out the heat transfer between two heat exchangers simultaneously around, realize the effective cyclic utilization to used heat.

The present application is described below by way of specific examples, which are intended to provide a better understanding of the contents of the application. It is to be understood that these examples are illustrative only and not limiting. The reagents used in the examples are, unless otherwise indicated, commercially available. The methods and conditions used in the examples are conventional methods and conditions, unless otherwise specified.

Examples

In the following examples, the reaction of n-esters with hydrogen chloride to produce ethephon is examined in the reactor of the present application. The following examples are merely specific examples cited in the present application, but the technical features of the present application are not limited thereto. Any simple changes, equivalent substitutions or other modifications made on the basis of the present application to solve the same technical problems and the same technical effects are all covered by the protection scope of the present application.

Example 1

In this example 1, the continuous acidolysis circulation reactor of the present application was constructed as shown in fig. 3, the reaction vessel was made of steel-lined enamel material, each pipe in the reaction system was made of steel-lined teflon material, the liquid circulation system included a front heat exchanger and a rear heat exchanger, both of which were tube-side silicon carbide-lined shell-and-tube heat exchangers, the circulation pump was made of steel-lined teflon material, the condenser of the gas separation-circulation system was a tube-side silicon carbide-lined shell-and-tube condenser, and the receiver was made of steel-lined enamel material.

The orthoester used in this example 1 was synthesized by the inventors in the laboratory according to known synthesis procedures.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.4MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating jacket outside the reaction kettle, and setting the temperature of the reaction kettle to be 130 ℃; starting a heat exchanger before the circulating pump, setting the temperature to be 120 ℃, starting a heat exchanger after the circulating pump, and setting the temperature to be 135 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 15 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.4Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 96 wt% from the discharge hole of the liquid circulation system at the flow rate of 1.02kg/h when the ethephon purity in the extracted liquid material reaches 96 wt%. At the same time, about 2.0kg/h of the reaction vessel was continuously replenished with the n-ester raw material (the n-ester raw material inlet was located at the top of the reaction vessel) and the hydrogen chloride raw material (the hydrogen chloride raw material inlet was located at the side wall of the suction chamber outside the nozzle of the venturi apparatus) so that the liquid level in the reaction vessel was kept constant. The pressure in the reaction vessel and in the gas separation-circulation system was maintained at 0.4MPa, and the flux of the fresh hydrogen chloride feed was 0.76kg/h. During this continuous reaction, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of example 1, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates indicated above, while maintaining the dichloroethane collection. During this continuous cycle, the liquid phase was sampled and analyzed, and the conversion of the n-ester feed was determined to be 95% by gas chromatography.

Example 2:

in this example 2 the same reactor and orthoester feedstock synthesized according to the prior art was used as in example 1.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.5MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating sleeve outside the reaction kettle, and setting the temperature of the reaction kettle to be 150 ℃; starting a heat exchanger before the circulating pump, setting the temperature to be 120 ℃, starting a heat exchanger after the circulating pump, and setting the temperature to be 155 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 15 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.5Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 96 wt% from the discharge hole of the liquid circulation system at the flow rate of 1.30kg/h when the ethephon purity in the extracted liquid material reaches 96 wt%. At the same time, about 2.5kg/h of the reaction vessel was continuously replenished with the n-ester raw material (the n-ester raw material inlet was located at the top of the reaction vessel) and the hydrogen chloride raw material (the hydrogen chloride raw material inlet was located at the side wall of the suction chamber outside the nozzle of the venturi apparatus) so that the liquid level in the reaction vessel was kept constant. The pressure in the reaction kettle and in the gas separation-circulation system is kept at 0.5Mpa, and the flux of the fresh hydrogen chloride replenishing raw material is 0.85kg/h. During this continuous reaction, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of example 2, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates indicated above, while maintaining the collection of dichloroethane. The liquid phase feed was sampled and analyzed during this continuous cycle and the conversion of the orthoester feed was 97% by gas chromatography.

Example 3:

in this example 3 the same reactor and orthoester feedstock synthesized according to the prior art was used as in example 1.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.3MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating jacket outside the reaction kettle, and setting the temperature of the reaction kettle to be 140 ℃; starting a heat exchanger before the circulating pump, setting the temperature to be 120 ℃, starting a heat exchanger after the circulating pump, and setting the temperature to be 145 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 15 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.5Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 96 wt% from the discharge hole of the liquid circulation system at the flow rate of 1.54kg/h when the ethephon purity in the extracted liquid material reaches 96 wt%. While continuously feeding about 3.0kg/h of a raw material of n-ester (inlet of n-ester raw material located at the top of the reaction vessel) and a raw material of hydrogen chloride (inlet of hydrogen chloride raw material located at the side wall of the suction chamber outside the nozzle of the venturi device) into the reaction vessel so that the liquid level in the reaction vessel was kept constant. The pressure in the reaction kettle and in the gas separation-circulation system is kept at 0.5Mpa, and the flux for replenishing the fresh hydrogen chloride raw material is 1.06kg/h. During this continuous reaction, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of example 3, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates indicated above, while maintaining the dichloroethane collection. The liquid phase feed was sampled and analyzed during this continuous cycle and the conversion of the orthoester feed was determined to be 96% by gas chromatography.

Example 4:

in this example 4 the same reactor and orthoester feedstock synthesized according to the prior art was used as in example 1.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.7MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating sleeve outside the reaction kettle, and setting the temperature of the reaction kettle to be 150 ℃; starting a heat exchanger before the circulating pump, setting the temperature to be 120 ℃, starting a heat exchanger after the circulating pump, and setting the temperature to be 155 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 10 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.7Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 96 wt% from the discharge hole of the liquid circulation system at the flow rate of 1.84kg/h when the ethephon purity in the extracted liquid material reaches 96 wt%. At the same time, about 3.5kg/h of the reaction vessel was continuously replenished with the n-ester raw material (the n-ester raw material inlet was located at the top of the reaction vessel) and the hydrogen chloride raw material (the hydrogen chloride raw material inlet was located at the side wall of the suction chamber outside the nozzle of the venturi apparatus) so that the liquid level in the reaction vessel was kept constant. The pressure in the reaction vessel and in the gas separation-circulation system was maintained at 0.7MPa, and the flux of the fresh hydrogen chloride feed was 1.04kg/h. During this continuous reaction, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of example 4, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates indicated above, while maintaining the dichloroethane collection. During this continuous cycle, the liquid phase was sampled and analyzed, and the conversion of the n-ester feed was determined to be 98% by gas chromatography.

Example 5

In this example 5 the same reactor and orthoester feedstock synthesized according to the prior art was used as in example 1.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.6MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating sleeve outside the reaction kettle, and setting the temperature of the reaction kettle to be 160 ℃; starting a heat exchanger before the circulating pump, setting the temperature to be 120 ℃, starting a heat exchanger after the circulating pump, and setting the temperature to be 165 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 5 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.6Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 96 wt% from the discharge hole of the liquid circulation system at the flow rate of 2.12kg/h when the ethephon purity in the extracted liquid material reaches 96 wt%. At the same time, about 4.0kg/h of the n-ester raw material (the n-ester raw material inlet is positioned at the top of the reaction kettle) and the hydrogen chloride raw material (the hydrogen chloride raw material inlet is positioned at the side wall of the suction chamber outside the nozzle of the Venturi device) are continuously supplemented into the reaction kettle, so that the liquid level in the reaction kettle is kept constant. The pressure in the reaction vessel and in the gas separation-circulation system was maintained at 0.6MPa, and the flux of the fresh hydrogen chloride feed was 1.14kg/h. During this continuous reaction, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of example 5, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates indicated above, while maintaining the dichloroethane collection. The liquid phase feed was sampled and analyzed during this continuous cycle and the conversion of the orthoester feed was 99% by gas chromatography.

As can be seen from the above inventive examples, the inventive examples all achieved excellent conversion of the raw materials and purity of the product. In addition, by adopting the continuous production process, the daily average yield reaches the level which is never achieved in the prior art.

Comparative example 1

In this comparative example 1, the same reactor and n-ester raw material synthesized according to the prior art as in example 1 were used, but no pre-circulating pump heat exchanger was employed, so that the temperature in the reaction tank and the temperature in the circulating line were restricted to 120 ℃ or lower.

The n-ester is put into the reaction kettle at one time to reach the preset liquid level height, the reaction kettle is sealed, nitrogen is filled to 0.2MPa, the sealing performance of the reaction kettle is detected, after the sealing performance is confirmed to be qualified, a straight-through valve at the tail gas absorption device is communicated, a vacuum pump connected to the straight-through valve is used for pumping out all the nitrogen in the reaction kettle, and then the straight-through valve at the straight-through valve is closed. Hydrogen chloride gas was charged into the reactor from the hydrogen chloride feed tank until the pressure measured at the back pressure valve was 0.4MPa, at which time the hydrogen chloride valve was temporarily closed. Starting a circulating pump in the liquid circulating system, starting heating of a heating sleeve outside the reaction kettle, and setting the temperature of the reaction kettle to be 115 ℃; starting a heat exchanger behind a circulating pump, and setting the temperature to be 120 ℃; starting the gas separation-circulation system, starting the condensing heat exchanger, and allowing the condensed water at 15 ℃ to flow in the condensing heat exchanger. And opening a hydrogen chloride valve again after the temperature reaches the set temperature, continuously introducing the hydrogen chloride into the reaction kettle according to the given flow, keeping the pressure in the reaction kettle and the pressure in the gas separation-circulation system at 0.4Mpa, starting acidolysis reaction, sampling the material from the discharge hole of the liquid circulation system for central control analysis, and continuously extracting the ethephon product with the purity of 65% from the discharge hole of the liquid circulation system at the flow of 1.02kg/h when the ethephon purity in the extracted liquid material reaches 65%. While continuously feeding about 2.0kg/h of a raw material of n-ester (inlet of n-ester raw material located at the top of the reaction vessel) and a raw material of hydrogen chloride (inlet of hydrogen chloride raw material located at the side wall of the suction chamber outside the nozzle of the venturi device) into the reaction vessel so that the liquid level in the reaction vessel was kept constant. The pressure in the reaction vessel and in the gas separation-circulation system was maintained at 0.4MPa, and the flux of the fresh hydrogen chloride feed was 0.76kg/h. During this continuous cycle, the receiver continuously receives the dichloroethane byproduct effluent from the bottom of the condenser. Under the process conditions of comparative example 1, the liquid level in the reactor was kept constant by withdrawing the liquid product and feeding the gas-liquid phase feed at the flow rates described above while maintaining the dichloroethane collection. The liquid phase material was sampled and analyzed, and the conversion of the n-ester feedstock was 70% by gas chromatography.

Claims (10)

1. A continuous acidolysis circulating reactor comprises a reaction kettle, a Venturi part, a liquid circulating system and a gas separating-circulating system,

the reaction kettle comprises a liquid outlet positioned at the bottom of the reaction kettle, and a gas inlet, a liquid inlet and a gas outlet positioned at the top of the reaction kettle;

the venturi part is a tubular part and comprises a venturi nozzle, a mixing section and a diffusion section from top to bottom, the lower part of the venturi part is inserted into the reaction kettle, and the upper part of the venturi part protrudes from the top of the reaction kettle;

the liquid circulation system comprises at least one heat exchanger and at least one circulating pump, and is in fluid communication with the liquid outlet of the reaction kettle and the venturi nozzle;

the gas separation-recycle system includes a condenser and a receiver, the gas separation-recycle system being in fluid communication with the gas outlet and the gas inlet of the reaction vessel.

2. The continuous acidolysis circulation reactor as claimed in claim 1, wherein the gas separation-circulation system is provided with a back pressure valve downstream of the condenser, the back pressure valve being configured to maintain a positive pressure within the reaction vessel.

3. The continuous acidolysis circulation reactor as claimed in claim 1, wherein a heating jacket is provided outside the reaction vessel;

at least one of the gas inlet and the liquid inlet is disposed at the venturi nozzle.

4. The continuous acidolysis circulation reactor as claimed in claim 1, wherein the liquid circulation system comprises at least two heat exchangers, wherein at least one heat exchanger is located upstream of the circulation pump and at least one heat exchanger is located downstream of the circulation pump.

5. The continuous acidolysis circulating reactor according to claim 1, wherein the reaction vessel, the venturi section, the liquid circulation system, and the gas separation-circulation system are each independently made of a material selected from the group consisting of: corrosion resistant metals, plastic materials, ceramic materials, silicon carbide materials, steel lined silicon carbide, steel lined plastics, steel lined glass and steel lined enamel.

6. A process for continuously carrying out a gas-liquid two-phase reaction carried out in a reactor as defined in any one of claims 1 to 5, preferably a reaction for the preparation of ethephon by acid hydrolysis, which comprises:

adding at least one gas-phase reactant into the reaction kettle through the gas inlet, and adding at least one liquid reactant into the reaction kettle through the liquid inlet, wherein the at least one gas-phase reactant and the at least one liquid reactant react in the reaction kettle to generate a liquid-phase product;

introducing at least a portion of the liquid phase material in the reaction vessel into a liquid circulation system, harvesting at least a portion of the liquid phase product, and circulating the remaining liquid phase material at least partially through a venturi section back into the reaction vessel;

at least a portion of the gas phase feed within the reaction vessel is introduced into the gas separation-recycle system, at least a portion of the gas phase by-product is separated and collected in a receiver, and the remaining gas phase feed is at least partially recycled back to the reaction vessel via the venturi section.

7. The method of claim 6, wherein the gas phase reactant is hydrogen chloride, the liquid phase reactant is 2-chloroethyl bis (2-chloroethyl) phosphate, the liquid phase product is ethephon, and the gas phase byproduct comprises dichloroethane.

8. The method of claim 6, wherein the gas separation-recycle system is provided with a back pressure valve downstream of the condenser, the back pressure valve being configured such that a gas pressure within the gas separation-recycle system is maintained at 0.40-0.70MPa and is the same as a pressure within the reaction vessel.

9. The method of claim 6, wherein the liquid phase reactant and the gas phase reactant are fed into the reaction vessel in a continuous manner and the liquid phase reactant and the gas phase reactant are fed in a molar ratio of 1.

10. The process of claim 6 wherein the liquid circulation system comprises at least two heat exchangers, at least one of which is located upstream of a circulation pump, at least one of which is located downstream of a circulation pump, the circulation pump having a temperature below the temperature in the reaction vessel, the heat exchanger located downstream of the circulation pump again raising the liquid stream to a temperature within the reaction vessel of ± 5 ℃.

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