CN114956947B - Separation method for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol - Google Patents
Separation method for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol Download PDFInfo
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Abstract
The invention discloses a separation method of a reaction solution for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol, which comprises the following steps: the reaction liquid and the phase transfer auxiliary agent are mixed and then enter a coalescer to realize three-phase separation of gas phase, oil phase and water phase, the gas phase at the top of the coalescer is cooled and then is removed from a gas-liquid separation tank, the gas phase is separated again at the top of the gas-liquid separation tank, and the oil-phase isopropylbenzene flow is extracted from the bottom; the water phase extracted from the water drum at the bottom of the coalescer is cooled and then mixed with the phase transfer auxiliary agent, and then enters an oil-water separation tank to realize oil-water separation again. Through the synergistic effect of the coalescer and the phase transfer auxiliary agent, the oil-water separation is efficiently and rapidly carried out in the coalescer, so that a large amount of free water is reduced in the oil phase, and the influence on the stability of the cumene refining system is avoided; the oil-water separation tank is used for separating oil from water again after the water phase extracted from the water drum at the bottom of the coalescer is mixed with the phase transfer auxiliary agent, so that the oil phase quantity entrained in the wastewater is reduced, and the operation of the wastewater treatment system is prevented from being influenced.
Description
Technical Field
The invention relates to a raw material treatment method for producing CHP by peroxidation of isopropylbenzene, belonging to the technical field of petrochemical industry.
Background
PO (propylene oxide, CAS number 75-56-9, molecular formula C) 3 H 6 O) is an important organic chemical product of propylene derivative, and is an important raw material for producing polyurethane, polyether and surfactant.
Industrial propylene oxide production methods include chlorohydrin method, co-oxidation method (Halcon method) and hydrogen peroxide direct oxidation method (HPPO method). Among them, the chlorohydrin method is one of the main methods for producing Propylene Oxide (PO) in China, and the domestic proportion is about 48%. The chlorohydrin method has the advantages of serious equipment corrosion, large amount of waste water and solid waste, serious environmental pollution and the like, and the method can realize phase-out in China. The direct oxidation method of hydrogen peroxide (HPPO method) has high cost of hydrogen peroxide, the economy is affected, and the running of the HPPO method in China has certain defects.
The co-oxidation method is also called co-production method or indirect oxidation method, and is characterized by that the reaction of organic peroxide and propylene is used to produce epoxypropane, at the same time the organic alcohol is by-produced, and mainly includes three processes of PO/TBA (MTBE), PO/SM and POCHP. The PO/MTBE method has the defects of longer flow and large equipment investment, and meanwhile, the MTBE market is gradually atrophic because the MTBE is forbidden to enter the oil blending market, so that the PO/MTBE process gradually loses the market in China. The PO/SM method has long process flow, large equipment investment, large waste water and waste gas amount, and along with the domestic large-scale smelting integration project, a plurality of PO/SM processes are intensively invested in domestic time, and the domestic SM market is seriously excessive, so that the release of PO productivity can be influenced in time.
Compared with other co-oxidation processes, the cumene co-oxidation process (POCHP) has obvious characteristics: short process route, less equipment investment, no product linkage, etc. The cumene co-oxidation method for generating propylene oxide is industrially utilized by Japanese Sumitomo, and comprises the following steps: the cumene is oxidized into Cumene Hydroperoxide (CHP) by air at a certain temperature and pressure, then the Cumene Hydroperoxide (CHP) is epoxidized with propylene to generate propylene oxide, and alpha, alpha-dimethylbenzyl alcohol generated by the epoxidation reaction is subjected to hydrogenolysis reaction to generate cumene, and the cumene is recycled to the peroxidation reaction, so that the recycling of the cumene is realized.
The difficulty in the cumene co-oxidation method is the hydrogenolysis reaction of α, α -dimethylbenzyl alcohol, and the separation of the hydrogenolysis reaction solution is very important. The hydrogenolysis reaction liquid comprises cumene and water generated by the reaction, unreacted hydrogen, alpha-dimethylbenzyl alcohol, cyclohexanol, cyclohexanone and other substances, alpha, substances such as alpha-dimethylbenzyl alcohol, cyclohexanone, cyclohexanol and the like are easy to emulsify with water, so that the reaction liquid has poor phase separation effect, water phase entrainment in oil phase cumene affects the refining of the cumene, and oil phase entrainment in the water phase affects the wastewater treatment.
Therefore, in order to solve the above-mentioned industry problem, a high-efficiency and running stable α, α -dimethylbenzyl alcohol hydrogenolysis reaction liquid separation system is needed, which not only can reduce the amount of free water entrained in the separated oil phase cumene, but also can avoid affecting the stability of the cumene refining system, and simultaneously can reduce the oil phase entrained in the water phase, and avoid affecting the downstream environmental protection treatment.
Disclosure of Invention
The alpha, alpha-dimethylbenzyl alcohol produced by epoxidation reaction of the cumene co-oxidation method is subjected to hydrogenolysis reaction to prepare cumene, the hydrogenolysis reaction liquid comprises cumene and water produced by the reaction, unreacted hydrogen, alpha-dimethylbenzyl alcohol, cyclohexanol, cyclohexanone and other substances, the reaction is difficult to realize phase separation under the conditions of high temperature, high pressure and high hydrogen flow rate, substances such as alpha, alpha-dimethylbenzyl alcohol, cyclohexanone, cyclohexanol and the like are easy to emulsify with water, so that the phase separation effect of reaction liquid is poor, the water phase carried in the oil-phase cumene affects the refining of the cumene, and the oil phase carried in the water phase affects the wastewater treatment.
In order to solve the industrial problems, the invention provides a separation method of a reaction solution for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol, which has the advantages that:
the method can efficiently realize the separation of gas phase, oil phase and water phase, and avoid the influence of the stability and energy consumption of the cumene refining system due to the fact that a large amount of free water is entrained in the oil; the water phase is separated into a small amount of oil phase through the oil-water separator, so that the oil content in the effluent is ensured to be stable, and the problem of downstream environmental protection treatment caused by the impact of the effluent fluctuation on environmental protection treatment facilities is avoided.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
1) The hydrogenolysis reaction liquid is mixed with phase transfer auxiliary agent, and the gas phase, oil phase and water phase are separated by a coalescer. As the unreacted alpha, alpha-dimethylbenzyl alcohol exists in the reaction liquid, an emulsion layer is formed at the oil-water two-phase interface, and water and oil two-phase layering is rapidly realized under the action of a phase transfer auxiliary agent;
2) The gas phase at the top of the coalescer enters a gas-liquid separation tank after passing through a demister, cumene is extracted from the bottom of the gas-liquid separation tank, and the gas phase at the top of the coalescer is extracted after passing through the demister and can return to the hydrogenolysis reactor;
mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then feeding the mixture into a cumene refining system;
the water phase is extracted from the water drum of the coalescer, the water phase contains easily emulsified organic matters such as alpha, alpha-dimethylbenzyl alcohol, cyclohexanol, isopropylbenzene and the like, dissolved hydrogen, the water phase and the phase transfer auxiliary agent are mixed and then enter an oil-water separation tank, the oil phase carried in the water phase is separated in the oil-water separation tank, the content of the organic matters in wastewater is reduced, meanwhile, the dissolved hydrogen in the water phase is removed in the oil-water separation tank, and the waste hydrogen phase enters a tail gas system.
In the technical scheme of the invention, an internal part which is formed by mixing metal wires and PTFE wires is arranged in the coalescer, the thickness of the internal part is 600-1200 mm, the purpose of coalescing liquid drops with the particle size of more than 30 mu m in materials into liquid drops with large particle size is achieved, and the oil phase-water phase separation is achieved; the height of the internal part accounts for 40-80%, preferably 60-76% of the diameter of the tank body, so that the gas phase flow rate is at the optimal level.
In the technical scheme of the invention, the gas phase discharge hole of the coalescer is provided with a defoaming internal part, a silk screen defoaming device and/or a high-performance blade defoaming device, preferably a high-performance blade defoaming device, and the thickness is generally selected to be 50-400 mm, preferably 150-250 mm.
In some embodiments, the hydrogenolysis reaction solution of the alpha, alpha-dimethylbenzyl alcohol contains 90-95% of cumene, 1-3% of water, 0.1-5% of alpha, alpha-dimethylbenzyl alcohol and 2-5% of hydrogen.
In the technical scheme of the invention, the hydrogenolysis reaction liquid of the alpha, alpha-dimethylbenzyl alcohol and the phase transfer auxiliary agent are mixed and then enter a coalescer, the hydrogenolysis reaction liquid realizes gas phase-oil phase-water phase separation in the coalescer, the content of the alpha, alpha-dimethylbenzyl alcohol in the reaction liquid is gradually increased along with the reduction of the activity of a hydrogenolysis reaction catalyst, the alpha, alpha-dimethylbenzyl alcohol and the water phase are easy to emulsify, and an emulsion layer appears at an oil-water interface. Under the action of the phase transfer auxiliary agent, the emulsion layer of the oil-water interface is quickly demulsified, so that a large amount of water phase is prevented from being entrained in oil, the refining of oil-phase isopropylbenzene is prevented from being influenced, and a large amount of oil phase is prevented from being entrained in the water phase and entering a wastewater system, and the treatment of wastewater is prevented from being influenced;
the phase transfer auxiliary agent is a hydrophilic oleophobic substance and is selected from one or more of tetraethylammonium bromide, tetrabutylammonium hydroxide, cetyltrimethylammonium bromide, imidazole ionic liquid and the like, preferably a composition of the imidazole ionic liquid and at least one quaternary ammonium salt (tetraethylammonium bromide, tetrabutylammonium hydroxide and cetyltrimethylammonium bromide), wherein the mass ratio of the ionic liquid to the quaternary ammonium salt is 1-4: 0.5 to the upper limit 2. The imidazole ionic liquid is brominated 1-octadecyl-3-nonylimidazole, and the preparation method can be referred to CN111153857A. The imidazole ionic liquid phase-splitting agent with the specific structure has high thermal stability and good surface activity, is due to delocalized electrons on imidazole rings and hydrogen bonding action among the imidazole rings, and simultaneously has synergistic action with a composition compounded by the traditional quaternary ammonium salt phase-splitting agent, so that the phase transfer auxiliary agent has high capability of reducing surface tension and good demulsification effect.
In the technical scheme of the invention, when entering the coalescer, the mass ratio of the phase transfer auxiliary agent to the hydrogenolysis reaction liquid is (0.001-0.005): 1, a step of;
in the technical scheme of the invention, the gas phase at the top outlet of the coalescer is cooled by a condenser, organic matters entrained in the gas phase are condensed, and the temperature of the condensed gas phase is 40-80 ℃;
the condensed gas phase enters a gas-liquid separation tank to realize gas-liquid separation, and a defoaming internal part is arranged at the top of the gas-liquid separation tank, wherein the defoaming internal part is generally a silk screen defoaming device and/or a blade defoaming device.
In the technical scheme of the invention, the water phase is extracted from the water drum at the bottom of the coalescer, the temperature of the water phase is reduced by a condenser, the temperature of the condensed water phase is 30-80 ℃, the condensed water phase and a phase transfer auxiliary agent are mixed and then enter an oil-water separation tank, and organic matters such as alpha, alpha-dimethylbenzyl alcohol, isopropylbenzene, cyclohexanol and the like in the water phase are further separated from the water phase; wherein, the mass ratio of the phase transfer auxiliary agent to the water phase is 0.001-0.005: 1, the optional range of the phase transfer auxiliary is the same as before.
In the technical scheme of the invention, the operating pressure of the oil-water separation tank is 0.05Mpag to 0.2Mpag, the pressure is reduced after the water phase enters the oil-water separation tank, hydrogen dissolved in the water phase is degassed in the oil-water separation tank, and the gas phase passes through a demister at the top of the gas-liquid separation tank and then is subjected to tail gas removal system, wherein the demister can be a wire mesh demister and/or a blade demister;
waste water is collected outside the bottom of the oil-water separation tank to a waste water treatment system, and the COD of the waste water is 1.2-3 ten thousand mg/L; and an oil skimming line in the middle of the oil-water separation tank performs oil skimming operation, so that the separated oil phase is prevented from entering wastewater.
In the technical scheme of the invention, the oil phase is extracted from the bottom of the coalescer, the water content in the oil phase is 0.10-0.68%, and the oil phase is mixed with the oil phase isopropylbenzene extracted from the bottom of the gas-liquid separation tank and then enters the isopropylbenzene refining system.
In the process of the present invention, the coalescer is operated at a pressure of 1.5MPaG to 3.2MPaG and at a temperature of 120℃to 210 ℃. The operating pressure of the gas-liquid separation tank is 0.2 MPaG-0.5 MPaG, the operating temperature is 40-100 ℃, the operating pressure of the oil-water separation tank is 0.05 MpaG-0.2 MpaG, and the operating temperature is 40-100 ℃. The residence time of the oil phase in the coalescer is 10 to 80 minutes, more preferably 20 to 50 minutes. The residence time of the oil phase of the gas-liquid separation tank is 15-40 min, more preferably 20-30 min, and the residence time of the water phase of the oil-water separation tank is 15-45 min, more preferably 25-40 min.
The invention has the positive effects that:
1) By adopting the method, the alpha, alpha-dimethylbenzyl alcohol hydrogenolysis reaction liquid can be quickly separated from gas phase, oil phase and water phase in a coalescer, and an emulsion layer in oil-water two phases is quickly separated by adding a phase transfer auxiliary agent, so that a large amount of free water is prevented from being entrained in the oil phase, the stability of a refining system of oil-phase cumene is prevented from being influenced, a large amount of oil phase is prevented from being entrained in the water phase, the energy consumption of the cumene refining system is reduced, and the biochemical treatability of wastewater is improved;
2) By adopting the method, the free oil phase in the water phase is further reduced by adding the phase transfer auxiliary agent in the water phase extracted from the coalescer, the water phase enters the oil-water separation tank to realize oil skimming through the middle port, and meanwhile, the dissolved hydrogen in the water phase is removed, so that the safety risk of wastewater treatment is reduced;
3) By adopting the method, the oil phase residence time is reduced, the equipment volume and the organic matter storage in the system are reduced, and the economy, the safety and the reliability of the process are improved by the separation of the coalescents and the action of the phase transfer auxiliary agent.
Drawings
FIG. 1 is a process flow diagram of the present invention
FIG. 2 is a process flow diagram of a comparative example
In the figure, (1) a coalescer, (2) a heat exchanger, (3) a gas-liquid separation tank, (4) a heat exchanger, and (5) an oil-water separation tank.
Detailed Description
Embodiments of the present invention will now be described in further detail with reference to the accompanying drawings and examples, which are all operated according to the operating conditions of the above technical solutions, but are not limited to the protection examples.
Analysis method
Gas phase analysis conditions: adopting an Agilent 7890B, a chromatographic column HP-5ms, and a vaporization chamber at 290 ℃ and a detector at 280 ℃; heating to 50deg.C for 2min; maintaining at 40 deg.c/min to 100 deg.c for 1min; heating to 200 ℃ at 10 ℃/min, and keeping for 2min; heating to 280 ℃ at 40 ℃ per minute, and keeping for 6 minutes.
The COD/BOD analysis method of the wastewater comprises the following steps: COD analyzer and BOD analyzer
The hydrogenolysis reaction liquid is produced by hydrogenolysis reaction in the process of producing propylene oxide by the cumene co-oxidation method of Wanhua chemical group Co., ltd.
As shown in figure 1, the reaction liquid generated by the hydrogenolysis reaction of the alpha, alpha-dimethylbenzyl alcohol and the phase transfer auxiliary agent are mixed, and then flow enters a coalescer, a gas phase pipeline at the top of the coalescer is connected with a heat exchanger, the gas phase is cooled by the heat exchanger and enters a gas-liquid separation tank, an outlet at the top of the gas-liquid separation tank is connected with the gas phase pipeline, an oil phase extracted from the bottom of the gas-liquid separation tank is mixed with an oil phase extracted from the bottom of the coalescer, then cumene is removed for refining, a water phase pipeline extracted from the bottom of the coalescer is connected with the heat exchanger, the water phase is cooled by the heat exchanger and mixed with the phase transfer auxiliary agent and then enters a deoiling water separation tank, the top of the oil-water separation tank is connected with the gas phase pipeline, a bottom extraction outlet is connected with a waste water pipeline, and an intermediate extraction outlet is connected with the oil phase pipeline.
And in FIG. 2, a reaction liquid generated from the hydrogenolysis reaction of the alpha, alpha-dimethylbenzyl alcohol is connected with a coalescer, a gas phase pipeline at the top of the coalescer is connected with a heat exchanger, the gas phase pipeline at the top of the coalescer is connected with an inlet of a gas-liquid separation tank after being cooled by the heat exchanger, a gas phase pipeline at the top of the gas-liquid separation tank is connected with a gas phase pipeline, an oil phase pipeline at the bottom of the gas-liquid separation tank is connected with an oil phase pipeline at the bottom of the coalescer, then cumene is removed for refining, a water phase pipeline at the bottom of the coalescer is connected with the heat exchanger, and the water phase pipeline at the bottom of the coalescer is connected with a waste water pipeline after being cooled by the heat exchanger.
Example 1:
the process flow is as in fig. 1. Wherein the coalescer internals are made of mixed braiding of metal wires and PTFE wires, the thickness of the internals is about 900mm, the internals height was 70% of the coalescer diameter height and the coalescer oil phase residence time was 30min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 350mm, a water drum is arranged at the bottom of the coalescer, and a partition plate is arranged in the middle to extract oil phase.
Hydrogenolysis solution (cumene content 94wt%, water content 2.5wt%, alpha, 0.2wt% of alpha-dimethylbenzyl alcohol, 3wt% of hydrogen and 0.3wt% of other components, wherein the following components are the same as the components) and have the pressure of 2MpaG, the temperature of 180 ℃, and the mass ratio of the alpha-dimethylbenzyl alcohol to the phase transfer auxiliary agent is 1:0.005 percent of the mixture enters a coalescer (1), the phase transfer auxiliary agent is an imidazole ionic liquid composition of 1-octadecyl-3-nonylimidazole bromide and tetraethylammonium bromide, and the mass ratio of the two is 2:1 (same below), the coalescer operating pressure was 1.5MPaG and the operating temperature was 180 ℃.
The gas phase extraction outlet at the top of the coalescer passes through a high-efficiency vane demister, the interception rate of liquid drops with the particle size of 20 mu m is 99.9 percent, the liquid drops are condensed to 40 ℃ by a heat exchanger (2) and enter a gas-liquid separation tank (3), the operating pressure of the gas-liquid separation tank is 0.2MPaG, the operating temperature is 40 ℃, the oil phase residence time is 25min, and the top gas phase returns to the hydrogenolysis reactor after free organic matters are removed by a wire mesh demister; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, is cooled to 50 ℃ by a condenser (4), and then is mixed with a phase transfer auxiliary agent according to the proportion of 1:0.005 is mixed and then is subjected to oil-water separation tank (5), the operating pressure of the oil-water separation tank is 0.1MpaG, the operating temperature is 50 ℃, the retention time of the water phase is 40min, hydrogen is removed in the oil-water separation tank, the hydrogen enters a tail gas treatment system after passing through a gas-phase demister, the water phase separates out entrained oil phase under the action of a phase transfer auxiliary agent, the oil phase is discharged through an intermediate oil skimming port, and waste water discharged from a bottom extraction port (subjected to COD analysis) is subjected to a waste water treatment system.
And mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then removing the cumene refining system.
Example 2:
the process flow is as in fig. 1. Wherein, the coalescer internals adopt metal wire and PTFE silk mixed knitting, and internals thickness is about 1200mm, and internals height accounts for 60% of coalescer diameter height, and coalescer oil phase dwell time 80min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 350mm, the bottom is provided with a water drum, and the middle is provided with a baffle plate for extracting an oil phase.
Hydrogenolysis hydraulic pressure 2.1MpaG generated by hydrogenolysis reaction of alpha, alpha-dimethylbenzyl alcohol, wherein the temperature is 150 ℃, and the mass ratio of the hydrogenolysis hydraulic pressure to the phase transfer auxiliary agent is 1:0.005 percent of the mixture enters a coalescer (1), the phase transfer auxiliary agent is an imidazole ionic liquid composition of 1-octadecyl-3-nonylimidazole bromide and tetraethylammonium bromide, and the mass ratio of the two is 4:0.5 (same applies below) the coalescer operating pressure was 1.5MPaG and the operating temperature was 150 ℃. Condensing the liquid drops with the particle size of 20 mu m to the interception rate of 99.9% by a high-efficiency blade demister through a gas phase extraction outlet at the top of a coalescer, entering a gas-liquid separation tank (3) after condensing the liquid drops to the temperature of 40 ℃ by a heat exchanger (2), enabling the gas-liquid separation tank to be 0.5MPaG, enabling the operation temperature to be 40 ℃, enabling the oil phase to stay for 20min, and enabling the top gas phase to return to a hydrogenolysis reactor after removing free organic matters by a wire mesh demister; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, is cooled to 50 ℃ by a condenser (4), and then is mixed with a phase transfer auxiliary agent according to the proportion of 1: and 0.005 of the wastewater treatment system is mixed, then the wastewater is subjected to oil-water separation tank (5), the operating pressure of the oil-water separation tank is 0.1MpaG, the operating temperature is 50 ℃, the retention time of the water phase is 20min, the hydrogen is removed in the oil-water separation tank, the hydrogen enters the tail gas treatment system after passing through the gas-phase demister, the water phase separates out entrained oil phase under the action of a phase transfer auxiliary agent, the oil phase is discharged through an intermediate oil skimming port, and the wastewater discharged from the bottom extraction port is subjected to the wastewater treatment system.
And mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then removing the cumene refining system.
Example 3
The process flow is as in fig. 1. Wherein the coalescer internals are made of mixed woven metal wires and PTFE wires, the thickness of the internals is about 600mm, the height of the internals accounts for 75% of the diameter height of the coalescer, and the oil phase residence time of the coalescer is 30min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 250mm, the bottom is provided with a water drum, and the middle is provided with a baffle plate to extract oil phase.
Hydrogenolysis liquid pressure 2.1MpaG generated by hydrogenolysis reaction of alpha, alpha-dimethylbenzyl alcohol, temperature 180 ℃, and phase transfer auxiliary agent according to mass ratio of 1:0.005 percent of the mixture enters a coalescer (1), the phase transfer auxiliary agent is an imidazole ionic liquid composition of 1-octadecyl-3-nonylimidazole bromide and cetyltrimethylammonium bromide, and the mass ratio of the two is 3:0.5 (same applies below) the coalescer operating pressure was 1.5MPaG and the operating temperature was 180 ℃. Condensing the liquid drops with the particle size of 20 mu m to the interception rate of 99.9% by a high-efficiency blade demister through a gas phase extraction outlet at the top of a coalescer, entering a gas-liquid separation tank (3) after condensing the liquid drops to the temperature of 40 ℃ by a heat exchanger (2), enabling the operation temperature of the gas-liquid separation tank to be 0.2MPaG, enabling the oil phase to stay for 25min at the operating temperature of 40 ℃, and removing free organic matters from the gas phase at the top by a wire mesh demister and then carrying out hydrogenolysis on the gas phase; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, is cooled to 50 ℃ by a condenser (4), and then is mixed with a phase transfer auxiliary agent according to the proportion of 1: and 0.005 of the wastewater treatment system is mixed, then the wastewater is subjected to oil-water separation tank (5), the operating pressure of the oil-water separation tank is 0.1MpaG, the operating temperature is 50 ℃, the retention time of the water phase is 40min, the hydrogen is removed in the oil-water separation tank, the hydrogen enters the tail gas treatment system after passing through the gas-phase demister, the water phase separates out entrained oil phase under the action of a phase transfer auxiliary agent, the oil phase is discharged through an intermediate oil skimming port, and the wastewater discharged from the bottom extraction port is subjected to the wastewater treatment system.
And mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then removing the cumene refining system.
Example 4
The process flow is as in fig. 1. Wherein, the coalescer internals adopt metal wire and PTFE silk mixed knitting, and internals thickness is about 1000mm, and internals height accounts for 72% of coalescer diameter height, and coalescer oil phase dwell time is 45min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 300mm, the bottom is provided with a water drum, and the middle is provided with a baffle plate for extracting an oil phase.
Hydrogenolysis liquid pressure 2.1MpaG generated by hydrogenolysis reaction of alpha, alpha-dimethylbenzyl alcohol, temperature 180 ℃, and phase transfer auxiliary agent according to mass ratio of 1:0.005 ratio and then enters a coalescer (1), wherein the phase transfer auxiliary agent is imidazole ionic liquid brominated 1-octadecyl-3-nonylimidazole (the same applies below), the operating pressure of the coalescer is 2.0MPaG, and the operating temperature is 175 ℃. Condensing the liquid drops with the particle size of 20 mu m to the interception rate of 99.9% by a high-efficiency blade demister through a gas phase extraction outlet at the top of a coalescer, entering a gas-liquid separation tank (3) at the pressure of 0.35MPaG by a heat exchanger (2), operating at the temperature of 40 ℃ and the oil phase residence time of 30min, removing free organic matters from the gas phase at the top by a wire mesh demister, and then carrying out hydrogenolysis; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, is cooled to 50 ℃ through a condenser (4), and then is mixed with a phase transfer auxiliary agent according to the mass ratio of 1:0.0045, the operating pressure of the oil-water separation tank is 0.1MpaG, the operating temperature is 50 ℃, the retention time of the water phase is 40min, the hydrogen is removed in the oil-water separation tank, the hydrogen enters the tail gas treatment system after passing through the gas-phase demister, the water phase separates the entrained oil phase under the action of the phase transfer auxiliary agent, the oil phase is discharged through the middle oil skimming port, and the waste water discharged from the bottom extraction port is discharged to the waste water treatment system.
And mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then removing the cumene refining system.
Comparative example 1
The process flow is as in fig. 2. Wherein, the coalescer internals adopt metal wire and PTFE silk mixed knitting, and internals thickness is about 1200mm, and internals height accounts for 70% of coalescer diameter height, and coalescer oil phase dwell time is 45min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 400mm, the bottom is provided with a water drum, and the middle is provided with a baffle plate to extract oil phase.
From the hydrogenolysis hydraulic pressure 2.1MpaG generated by the hydrogenolysis reaction of alpha, alpha-dimethylbenzyl alcohol, the temperature 180 ℃ enters a coalescer (1) with an operating pressure of 2.0MpaG and an operating temperature of 180 ℃. The gas phase extraction outlet at the top of the coalescer passes through a high-efficiency vane demister, the interception rate of liquid drops with the particle size of 20 mu m is 99.9 percent, the liquid drops are condensed to 40 ℃ by a heat exchanger (2) and enter a gas-liquid separation tank (3), the pressure of the gas-liquid separation tank is 0.45MPaG, the operation temperature is 40 ℃, the oil phase residence time is 30min, and the top gas phase is returned to the hydrogenolysis reactor after free organic matters are removed by a wire mesh demister; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, and after being cooled to 50 ℃ by a condenser (4), the water phase is discharged to a wastewater treatment system.
And mixing the oil phase extracted from the bottom of the coalescer with the oil phase extracted from the bottom of the gas-liquid separation tank, and then removing the cumene refining system.
Comparative example 2
The process flow is as in fig. 2. Wherein, the coalescer internals adopt metal wire and PTFE silk mixed knitting, and internals thickness is about 900mm, and internals height accounts for 60% of coalescer diameter height, and coalescer oil phase dwell time 60min. The demister at the gas phase outlet in the coalescer adopts a high-efficiency blade demister with the thickness of 400mm, the bottom is provided with a water drum, and the middle is provided with a baffle plate to extract oil phase.
The hydrogenolysis liquid pressure from the hydrogenolysis reaction of α, α -dimethylbenzyl alcohol was 2.1MpaG at 180℃into coalescer (1) operating at 2.0MPaG and 170 ℃. Condensing the liquid drops with the particle size of 20 mu m to the interception rate of 99.9% by a high-efficiency blade demister through a gas phase extraction outlet at the top of a coalescer, entering a gas-liquid separation tank (3) at the pressure of 0.5MPaG by a heat exchanger (2), operating at the temperature of 40 ℃ and the oil phase residence time of 30min, removing free organic matters from the gas phase at the top by a wire mesh demister, and then carrying out hydrogenolysis; and oil-phase isopropylbenzene is extracted from the bottom.
The water phase is extracted from the water bag at the bottom of the coalescer, and after being cooled to 50 ℃ by a condenser (4), the water phase is discharged to a wastewater treatment system.
Oil phase extraction at bottom of coalescer and bottom of gas-liquid separation tank the produced oil phase is mixed and then is removed from the isopropylbenzene refining system.
Analysis of the water content of cumene extracted from the bottom oil phase of the coalescers in examples and comparative examples, and analysis of COD in the effluent wastewater, were performed as follows:
(note: wastewater biodegradability B/C is an index for evaluating wastewater biodegradability in industry, and when B/C is less than 0.3%, the wastewater is difficult to biochemically treat, and the lower the value is, the more difficult to biochemically treat is).
Claims (12)
1. A method for separating hydrogenolysis reaction liquid for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol is characterized by comprising the following steps:
1) Mixing the hydrogenolysis reaction liquid with a phase transfer auxiliary agent, and separating three phases of gas phase, oil phase and water phase through a coalescer; wherein, the phase transfer auxiliary agent is selected from one or more of tetraethylammonium bromide, tetrabutylammonium hydroxide, cetyltrimethylammonium bromide and imidazole ionic liquid;
2) The gas phase at the top of the coalescer enters a gas-liquid separation tank after passing through a defoaming internal part, cumene is extracted from the bottom of the gas-liquid separation tank, and the gas phase at the top of the coalescer is extracted after passing through the defoaming internal part;
oil phase and gas-liquid separation tank extracted from bottom of coalescer the oil phase extracted from the bottom is removed from the cumene refining system;
the water phase is extracted from the water drum of the coalescer, and the water phase and the phase transfer auxiliary agent are mixed and then enter an oil-water separation tank for separation.
2. The method of claim 1, wherein the phase transfer aid is selected from the group consisting of a composition of an imidazole ionic liquid and at least one quaternary ammonium salt, wherein the mass ratio of ionic liquid to quaternary ammonium salt is 1-4: 0.5-2.
3. The method of claim 1, wherein the imidazole ionic liquid is brominated 1-octadecyl-3-nonylimidazole.
4. The method according to any one of claims 1 to 3, wherein the mass ratio of the phase transfer auxiliary agent to the hydrogenolysis reaction liquid is (0.001 to 0.005): 1.
5. the method of claim 1, wherein the coalescer is provided with an inner piece of mixed woven metal wire and PTFE wire, the thickness of the inner piece is 600-1200 mm, and the height of the inner piece is 40-80% of the diameter of the tank body.
6. The method of claim 5, wherein the coalescer is operated at a pressure of 1.5MPaG to 3.2MPaG, at a temperature of 120 to 210 ℃, and an oil phase residence time in the coalescer of 10 to 80 minutes.
7. The method according to any one of claims 1-3 and 5-6, wherein the demister internals are arranged at the gas phase discharge port of the coalescer and are wire mesh demisters and/or high-performance blade demisters, and the thickness is 50-400 mm;
and cooling the gas phase at the top outlet of the coalescer to 40-80 ℃ through a condenser, and then entering a gas-liquid separation tank.
8. The method of claim 1, wherein the gas-liquid separation tank is operated at a pressure of 0.2-0.5 mpa g and at a temperature of 40-100 ℃ and a residence time of the gas-liquid separation tank oil phase of 15-40 min.
9. The method of claim 1, wherein the coalescer bottom produces an aqueous phase in a water drum, and the aqueous phase is cooled to 30-80 ℃ by a condenser.
10. The method according to claim 1 or 9, wherein the mass ratio of the phase transfer auxiliary to the aqueous phase is 0.001-0.005: 1.
11. the method of claim 1, wherein the oil-water separation tank is operated at a pressure of 0.05-0.2 mpa g, at a temperature of 40-100 ℃ and a water phase residence time of 15-45 min.
12. A method according to claim 1 or 11, wherein after the aqueous phase enters the oil-water separator tank, the gas phase passes through a top demister and then goes to a tail gas system, wherein the demister is a wire mesh demister and/or a vane demister; waste water is collected outside the bottom to a waste water treatment system; and the middle oil skimming line performs oil skimming operation.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102295534A (en) * | 2010-06-24 | 2011-12-28 | 中国石油化工股份有限公司 | Method for preparing alpha, alpha-dimethyl benzyl alcohol |
| CN112473734A (en) * | 2020-12-07 | 2021-03-12 | 万华化学集团股份有限公司 | Method for preparing isopropyl benzene by coupling reaction, rectification and hydrogenation of dimethyl benzyl alcohol |
| CN112661585A (en) * | 2019-10-15 | 2021-04-16 | 中国石油化工股份有限公司 | Method for preparing isopropylbenzene by hydrogenolysis of alpha, alpha dimethyl benzyl alcohol and application |
| CN114436757A (en) * | 2020-10-16 | 2022-05-06 | 中国石油化工股份有限公司 | Method, system and application for treating hydrogenolysis product of alpha, alpha-dimethyl benzyl alcohol |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102295534A (en) * | 2010-06-24 | 2011-12-28 | 中国石油化工股份有限公司 | Method for preparing alpha, alpha-dimethyl benzyl alcohol |
| CN112661585A (en) * | 2019-10-15 | 2021-04-16 | 中国石油化工股份有限公司 | Method for preparing isopropylbenzene by hydrogenolysis of alpha, alpha dimethyl benzyl alcohol and application |
| CN114436757A (en) * | 2020-10-16 | 2022-05-06 | 中国石油化工股份有限公司 | Method, system and application for treating hydrogenolysis product of alpha, alpha-dimethyl benzyl alcohol |
| CN112473734A (en) * | 2020-12-07 | 2021-03-12 | 万华化学集团股份有限公司 | Method for preparing isopropyl benzene by coupling reaction, rectification and hydrogenation of dimethyl benzyl alcohol |
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