CN111574318B - Energy-saving reaction process for producing ethylbenzene from pure ethylene - Google Patents
Energy-saving reaction process for producing ethylbenzene from pure ethylene Download PDFInfo
- Publication number
- CN111574318B CN111574318B CN202010500063.9A CN202010500063A CN111574318B CN 111574318 B CN111574318 B CN 111574318B CN 202010500063 A CN202010500063 A CN 202010500063A CN 111574318 B CN111574318 B CN 111574318B
- Authority
- CN
- China
- Prior art keywords
- benzene
- reaction
- ethylbenzene
- ethylene
- alkylation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
- C07C2/54—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition of unsaturated hydrocarbons to saturated hydrocarbons or to hydrocarbons containing a six-membered aromatic ring with no unsaturation outside the aromatic ring
- C07C2/64—Addition to a carbon atom of a six-membered aromatic ring
- C07C2/66—Catalytic processes
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/12—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Abstract
The invention relates to an energy-saving reaction process for producing ethylbenzene by using pure ethylene, which comprises the following steps: treating the raw material benzene to ensure that the benzene discharge at the top of the benzene recovery tower contains 30-600PPM of water; protecting adsorption reaction to make the content of basic nitrogen in the material entering the alkylation reactor less than 0.001 PPM; performing alkylation reaction, wherein each two catalyst bed layers are correspondingly provided with a steam generator, and a stage discharge formed after the reaction of each two catalyst bed layers enters the steam generator for heat exchange and then enters the next stage of alkylation reaction; recovering benzene; recovering ethylbenzene; recovering polyethylbenzene; and (4) carrying out anti-alkylation reaction. The process provided by the invention solves the problem of influence of impurities of the raw materials on the device, improves the stability of the ethylbenzene reaction system and reduces the production cost.
Description
Technical Field
The invention belongs to the technical field of chemical industry, and particularly relates to a raw material treatment and energy-saving reaction process for producing ethylbenzene by using pure ethylene.
Background
The invention belongs to a raw material treatment and low-pressure-drop reaction energy-saving process for producing ethylbenzene by pure ethylene and benzene alkylation (also called alkylation), which mainly comprises a raw material benzene impurity treatment process and a low-pressure-drop alkylation reaction energy-saving process, and the reaction energy-saving process is combined with an ethylbenzene separation process, so that the overall energy saving of a device is realized, the stability of the device is improved, and the economy of the ethylbenzene device is improved.
Ethylbenzene is an important chemical raw material, is mainly used for producing chemical raw material monomer styrene through dehydrogenation, has large market consumption, and is generally constructed as a combined device with a styrene device. At present, the production of ethylbenzene mainly adopts a production method of alkylating benzene and ethylene, and the benzene and the ethylene are synthesized by Friedel-Crafts alkylation reaction under the action of an acid catalyst, and the reaction formula is as follows:
the ethylbenzene produced will undergo a further polyalkylation reaction with ethylene to produce diethylbenzene and polyethylbenzene.
After the diethylbenzene and polyethylbenzene in the reaction product are rectified and separated, ethylbenzene is obtained by adopting a method of transalkylation (also called as "anti-alkylation") with benzene and returned to the system.
According to different ethylene sources, the production of ethylbenzene is divided into a pure ethylene method (raw material ethylene is polymerization-grade ethylene) and a dilute ethylene method (raw material is ethylene-containing dry gas, generally referred to as catalytic cracking dry gas), and because of large supply quantity of pure ethylene raw materials in the market and large-scale production requirements of ethylbenzene, more than 90% of industrially operated ethylbenzene plants produce ethylbenzene by using the pure ethylene raw materials. In addition, in the aspect of pure ethylene production process, the liquid phase method process has the advantages of mild reaction conditions, good quality of ethylbenzene products, low energy consumption and material consumption and the like, so that most of the ethylbenzene devices which are industrially operated at present adopt the pure ethylene liquid phase method production process.
However, the industrial and practical pure ethylene liquid phase method process has certain problems, which affect the stability and economy of the device, the biggest factor is that the water content of the raw material benzene and the content change of the alkaline nitrogen impurity affect the stable operation of the process, and some devices even have the condition that the catalyst is inactivated only after being operated for months because of the ultrahigh content of the raw material benzene impurity, so that the device can not be operated. In addition, with the increasingly competitive market of ethylbenzene, each unit of use focuses on reducing the production cost by improving the process technology, wherein the research on the ethylbenzene energy-saving process is the most, and particularly, how to reduce the power consumption with the highest energy consumption ratio of an ethylbenzene device becomes a hotspot of process research. The following reports on the effect of feed impurities and the energy saving technology of ethylbenzene are illustrative.
Patent CN205635419U reports a liquid phase alkylation reaction process of ethylene and benzene, the system includes an ethylene feeding pipe, a benzene feeding pipe, a protective reactor, an alkylation reactor and a steam generator, the benzene feeding pipe is communicated with the protective reactor, after the ethylene and benzene are mixed, heat is extracted through the steam generator after passing through three catalyst bed layers, nine-stage feeding of ethylene and three-stage heat extraction are generally adopted, the problem of selectivity reduction caused by reduction of local benzene/olefin ratio is solved, and high-pressure steam of more than 3.5MPaG can be produced. The method does not consider the actual industrialized operation and the performance condition of an alkylation catalyst, the current industrialized device basically adopts a nine-section feeding and three-section heat taking mode, and the ethylene distributor is reasonably arranged, so that the reaction effect is not influenced by adopting 2 sections of catalyst beds and three sections of catalyst beds; in addition, the reaction temperature of the alkylation catalyst needs to be controlled below 250 ℃, and more residual oil components are generated due to overhigh reaction temperature, but the report shows that the byproduct of high-pressure steam with the pressure higher than 3.5MPaG needs to be increased to the reaction temperature of the material above 250 ℃, so that the residual oil is increased, the material consumption of the device is increased, and the ethylbenzene alkylation reaction system is not suitable for generating high-pressure steam with the pressure higher than 3.5MPaG by comprehensively considering the using conditions of the catalyst, and the industrial device does not have the case.
The invention discloses a CN103539599A method for preparing ethylbenzene by benzene and ethylene liquid phase alkylation, which mainly solves the problem that the reaction selectivity of a catalyst is influenced by uneven mixing of materials between sections caused by uniform space between two adjacent catalyst beds in a multi-section adiabatic fixed bed reactor in the prior document. The technical scheme that the distance between two adjacent catalyst beds is gradually increased from bottom to top is adopted, so that the problem is solved. However, in the actual commercial plant, a reasonable ethylene distributor is used, which can solve the mixing problem without increasing the distance between beds.
In order to solve the problem of raw material impurities, the patent reports that the catalyst performance is basically improved to solve the problem, and the patent CN106946643A adopts a modified multistage reactor, wherein an A section at the middle lower part of the reactor is filled with an H-MWW molecular sieve catalyst, the other part of the reactor is filled with an H-BEA molecular sieve catalyst, part of benzene and ethylene at the A section are respectively introduced from each stage of the reactor for reaction, part of benzene at the B section is fed from the bottom, and ethylene is fed from the bottom for reaction in a staged manner. The liquid-phase alkylation reaction is carried out under the combined action of the H-MWW and the H-BEA, so that the conversion rate and the stability of ethylene in the reaction are improved. In addition, patents CN105566050A, CN101688130A, CN101190871A, etc. also improve the similar reports of the alkylation reaction system for controlling raw material impurities by improving the preparation process of the acidic catalyst, but none of them have been industrialized.
Therefore, it can be seen comprehensively that the above patents mainly adopt a method of improving the performance of the catalyst to improve the stability of the ethylbenzene reaction system, the reports of process solutions are few, and the actual situation of industrial operation is separated, so that the problems of influence of raw material impurities on the stability of the device, energy conservation and production cost reduction cannot be solved well.
Disclosure of Invention
In order to overcome the defects, the invention aims to provide an energy-saving process for alkylation reaction of ethylene and benzene under a liquid phase condition, which adopts three-stage processes of a raw material impurity processor and a parallel feeding dehydration and protection reactor, solves the influence of raw material impurities on a device, improves the stability of an ethylbenzene reaction system and reduces the production cost.
In order to achieve the purpose, the technical scheme of the invention is as follows:
an energy-saving reaction process for producing ethylbenzene by using pure ethylene comprises the following steps:
a. treating raw material benzene: the method is characterized by comprising two impurity adsorbers I, two impurity adsorbers II, a light component removal tower and a benzene recovery tower, wherein raw material benzene is divided into two strands, and the first strand of raw material benzene is subjected to impurity removal through the impurity adsorber I and then returns to the top of the benzene recovery tower; the second strand of raw material benzene is dehydrated by a light component removal tower, and is returned to the top of the benzene recovery tower after impurity removal by the impurity absorber II; controlling the proportion of the first strand of raw material benzene to the second strand of raw material benzene to ensure that the water content of the benzene discharge at the top of the benzene recovery tower is 30-600 PPM;
b. protection reaction: the device is provided with an alkylation reactor and a protection reactor, and raw material ethylene is divided into alkylation reaction ethylene and a small amount of protection reaction ethylene; averagely dividing alkylation reaction ethylene into n parts, wherein the ethylene fraction n corresponds to the number of catalyst beds in an alkylation reactor; the protective reaction ethylene and the benzene discharged material after temperature rise enter a protective reactor for protective adsorption reaction;
c. alkylation reaction: the alkylation reactor is provided with a steam generator, and each two layers of catalyst beds arranged in the alkylation reactor are correspondingly provided with one steam generator from the first catalyst bed; the protective reaction discharge and the first part of ethylene in the n parts of ethylene enter a first catalyst bed layer of an alkylation reactor for alkylation reaction; then adding one part of ethylene to carry out alkylation reaction before entering one catalyst bed layer normally; and the staged discharge formed after the reaction of every two catalyst bed layers enters a steam generator for heat exchange and then enters the next stage of alkylation reaction;
d. and (3) benzene recovery: the reaction material of the last stage formed from the top of the alkylation reactor enters a benzene recovery tower for benzene recovery and forms a benzene discharge together with the treated raw material benzene;
e. ethylbenzene recovery: an ethylbenzene recovery tower is arranged, and the produced material at the bottom of the benzene recovery tower enters the ethylbenzene recovery tower to recover ethylbenzene;
f. and (3) polyethylbenzene recovery: a polyethylbenzene recovery tower is arranged, and the material at the bottom of the ethylbenzene recovery tower enters the polyethylbenzene recovery tower to recover polyethylbenzene;
g. and (3) reverse alkylation reaction: and arranging an anti-alkylation reactor, extracting part of benzene from the benzene discharge material before temperature rise and feeding the part of the benzene and polyethylbenzene recovered by the polyethylbenzene recovery tower into the anti-alkylation reactor for anti-alkylation reaction, and feeding the reacted material into the benzene recovery tower.
As a further improvement of the invention: the benzene recovery tower is provided with a condenser, benzene discharged material formed at the top of the benzene recovery tower is condensed by the condenser, and gas-phase benzene in the condensed benzene discharged material enters the light component removal tower to be used as a heat source for maintaining the operation of the light component removal tower.
As a further improvement of the invention: and (4) arranging a heat exchanger, wherein the first stage discharge formed in the step (c) enters the heat exchanger to exchange heat with the benzene discharge and then enters a corresponding steam generator, so that the temperature of the first stage discharge at about 240 ℃ is fully utilized, and the utilization rate of energy is improved.
As a preferred embodiment of the present invention: the discharging temperature formed after the staged discharging formed in the step (c) passes through the steam generator is 200-210 ℃. The step discharge formed in the step (c) is 240-245 ℃.
As a further improvement of the invention: the discharging temperature formed after the heat exchange of the steam generator is carried out in a steam pressure cascade control mode with the steam generator; and the temperature of the steam generated by the steam generator is not lower than 182 ℃.
Because the alkylation reactor system is a low-pressure-drop reaction system, the feeding temperature entering the catalyst bed layer after heat exchange by the steam generator adopts a mode of steam pressure cascade control with the steam generator, so that the staged discharging enters the steam generator without valve control of a regulating valve, a hand valve and the like, the whole heat exchange system only needs one set of safety valve system to meet the requirement, the number of the valves and the safety valves is reduced by 90 percent, and the leakage probability of a high-pressure system of the alkylation reaction system is reduced; meanwhile, the operating pressure of the medium-pressure steam generated by the steam generator is 0.8-2.0 MPaG, preferably 1.0-1.6 MPaG; therefore, the traditional control mode of combining the bypass and the regulating valve is changed, the mode of combining the bypass and the regulating valve needs the pressure drop matching of the bypass regulating valve and the main regulating valve to achieve the purpose of flexible regulation, and the pressure drop of the reaction system is increased by 200-500 KPa correspondingly.
After the cascade control mode is adopted, no valve is cut off between the alkylation reactor and the steam generator, the pressure drop of a corresponding reaction system is reduced by 100-600 KPa, preferably 300-500 KPa, under the condition that the outlet pressure of the reactor is kept unchanged at 3.0MPa, the inlet pressure of the alkylation reactor is reduced by 300-500 KPa, and similarly, the power consumption of raw material pressurization equipment entering the reaction system, such as a circulating benzene pump, an ethylene compressor and the like, is greatly reduced, and the total power consumption of the ethylbenzene device can be reduced by about 15 percent due to the part of power consumption saving.
As a further improvement of the invention: in order to well solve the influence of raw material impurities on the stability of the device, a protective catalyst with strong alkaline nitrogen adsorption capacity is arranged in the protective reactor, and the content of alkaline nitrogen in a protective reaction discharge material formed after adsorption reaction of the protective reactor is less than 0.001 PPM.
As a further improvement of the invention: the ethylbenzene recovery tower adopts a vacuum separation technology and utilizes steam formed by a steam generator for heating. After the ethylbenzene recovery tower adopts the vacuum separation technology, the temperature of the material at the tower bottom of the ethylbenzene recovery tower can be controlled to be not higher than 175 ℃, so that steam can be fully utilized as a heat source to heat the material at the tower bottom, and the energy is greatly saved.
As a further improvement of the invention: the dosage of the small amount of the protective reaction ethylene is 1/3-3/4 of the dosage of each piece of ethylene entering each catalyst bed layer.
The invention is designed aiming at raw materials, adopts a treatment process of impurity water and alkaline nitrogen, and can control the water and the alkaline nitrogen entering the alkylation reactor to be at the level required by the alkylation reaction by arranging a three-stage protection process of an impurity processor, a light component removal tower and a protection reactor. Therefore, the stability problem of the reaction is solved from the process source, and the efficiency and the stability of an ethylbenzene reaction system and a reaction device are improved.
The invention controls the reaction conditions in the alkylation reaction system by adopting a mode of cascade control of the reaction temperature entering the catalyst bed and the generated steam pressure, reduces the pressure drop loss of heat extraction between catalyst sections, reduces the inlet pressure of the reactor, and reduces the energy consumption of raw material pressurization. Meanwhile, the medium-pressure steam which is a byproduct of the low-pressure-drop alkylation reactor is combined with the separation of the ethylbenzene tower, so that the energy consumption of the ethylbenzene device is reduced, and the production cost is greatly reduced.
Drawings
FIG. 1 is a process design of the present invention;
in the figure: 1. an alkylation reactor; 2. a steam generator; 3. protecting the reactor; 4. a benzene recovery column; 5. a light component removal tower; 6. a first impurity adsorber; 7. a second impurity adsorber; 8. an ethylbenzene recovery column; 9. a polyethylbenzene recovery column; 10. a polyethylbenzene booster pump; 11. an anti-alkylation reactor; 12. a benzene alkylation booster pump; 13. a heat exchanger; and 14 is a condenser.
Detailed Description
The processes, features and advantages of the present invention are further described in the following examples. The embodiments of the present invention are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the scope of the present invention by substituting or changing the equivalent technical solution and the inventive concept of the present invention.
Example 1, as shown in fig. 1: the equipment related to the embodiment comprises a alkylation reactor 1, three steam generators 2, a protection reactor 3, a benzene recovery tower 4, a light component removal tower 5, an impurity adsorber I6 and an impurity adsorber II 7; an ethylbenzene recovery tower 8, a polyethylbenzene recovery tower 9 and an anti-alkylation reactor 11.
As shown in fig. 1: the method comprises the following steps of firstly treating impurity components of raw material benzene, then recycling the impurity components back to a alkylation reaction system, and specifically comprises the following steps: firstly, regarding the control of impurity water, dividing the raw material benzene into two streams of material flows, wherein one stream of material flow enters the top of the benzene recovery tower 4 after passing through the second impurity adsorber 7, and the benzene of the material can remove part of water due to phase balance factors, and the water content in the material is controlled to be recycled to the benzene recovery tower 4; two strands of raw material benzene is used as the feeding material of the light component removal tower 5, water in the raw material benzene is completely removed by utilizing the evaporation and phase equilibrium of benzene steam, the dehydrated dry benzene enters the top of the benzene recovery tower 4 through the impurity adsorber I6, is mixed with the first treated raw material benzene and the benzene in the benzene recovery tower 4, is finally condensed by the condenser 14 and then is pressurized by the alkylation benzene booster pump 12 to return to the alkylation reactor 1 to be used as a circulating raw material, and the benzene steam which is not condensed returns to the light component removal tower 5 to be used as a heat source of the light component removal tower.
Controlling the flow ratio of the two streams of raw material benzene, so that the water content in the circulating raw material benzene returned to the alkylation reactor can be controlled to be 30-600PPM, preferably 200-300 PPM, and in the embodiment, 250 PPM; because a small amount of water participates in the alkylation reaction process, a beta-type alkylation catalyst meeting the water-resistant content can be selected, and the catalyst meets the requirements of the ethylene liquid-phase alkylation reaction, so that the water tolerance of an alkylation reaction system is improved, and the stability of the reaction system is improved.
Next, regarding the treatment of basic nitrogen, it is considered that the alkylation catalyst is an acidic catalyst, and the basic nitrogen should be completely treated. Firstly, through the treatment process of the water content, the water content is controlled to be in a state of basically having no influence on the adsorption position of the basic nitrogen. Two impurity adsorbers are used for firstly adsorbing about 90% of basic nitrogen, and the residual basic nitrogen is used for removing the basic nitrogen in reaction materials under the reaction activity condition through a protection catalyst in a protection reactor, so that the phenomenon that the materials are poisoned and inactivated to a liquid phase alkylation reactor is prevented. In the present example, an adsorbent having a strong basic nitrogen adsorption capacity, for example, 13X or the like, is used as a filler of the two impurity adsorbers, depending on the basic nitrogen in the raw material benzene mainly consisting of morpholine, azamethyl pyrrolidone, or the like.
According to the invention, a small amount of ethylene is introduced into the protective reactor to maintain the reaction activity, the flow rate of the small amount of ethylene introduced into the protective reactor 3 is controlled within the range of 100-1600 kg/h, preferably 500-600 kg/h, which is 3/5 of the flow rate of each piece of ethylene entering each layer of catalyst bed layer. After the protective adsorption reaction, the content of alkaline nitrogen in the discharge material of the protective reactor 3 is less than 0.01 PPM. In this embodiment, the reaction pressure of the protective reactor 3 is generally controlled to be 3.2 to 3.6MPa, the reaction temperature is generally controlled to be 200 to 210 ℃, in this embodiment, the pressure is 3.4MPa, and the temperature is 205 ℃.
As shown in fig. 1: the corresponding process of the embodiment is as follows:
the raw material benzene is returned to the top of the ethylbenzene recovery tower 4 after impurity treatment and enters a condenser for condensation together with benzene distilled from the top of the ethylbenzene recovery tower 4, the condensed liquid phase benzene enters a heat exchanger for heat exchange to 205 ℃ under the control of flow rate after being pressurized by a benzene alkylation booster pump 12, and then is mixed with a small amount of protective reaction ethylene and introduced into a protective reactor 3; the raw material ethylene is averagely divided into eight parts after deducting a small amount of protective reaction ethylene, and the eight parts are used for corresponding 8 layers of catalyst bed layers in a alkylation reactor;
the protective reaction discharge material of the protective reactor 3 is mixed with a first part of ethylene and enters a first catalyst bed layer of an alkylation reaction to carry out the alkylation reaction to generate components such as ethylbenzene, diethylbenzene, triethylbenzene and the like, the formed reaction discharge material is mixed with a second part of ethylene and enters a second catalyst bed layer to react to form a first stage discharge material with the temperature of about 243 ℃, and the first stage discharge material enters a first steam generator 2 after heat exchange and temperature reduction through a heat exchanger 13; controlling the temperature of the reaction material in cascade by steam pressure of the steam generator 2 to reduce the temperature of the first stage discharge entering the third catalyst bed to 205 ℃, mixing the reaction material with the third part of ethylene to enter the third catalyst bed for alkylation reaction, mixing the reaction material with the fourth part of ethylene to enter the fourth catalyst bed for reaction, forming a second stage discharge with the temperature of about 243 ℃, entering the second steam generator 2, controlling the temperature of the reaction material in cascade by steam pressure of the steam generator 2 to reduce the temperature of the second stage discharge to 205 ℃, mixing the reaction material with the fifth part of ethylene to enter the fifth catalyst bed; the rest is repeatedly carried out according to the flow of the third and fourth alkylation reactions, and finally the alkylation reaction materials flow out of the reaction device from the top of the alkylation reactor 1 and enter a benzene recovery tower 4 to process the reaction materials. The small amount of ethylene entering the guard reactor 3 in this system maintains the guard catalyst in the reaction state.
Benzene is distilled from the top of the benzene recovery tower 4, part of the benzene is extracted in a gas phase mode and enters a dehydrogenation component tower 5 to be used as a heat source of the tower to maintain the tower operation, and most of the benzene returns to a reaction section in a liquid phase mode to be used as raw material benzene for alkylation and anti-alkylation reactions; the material rich in ethylbenzene is extracted from the bottom of the benzene recovery tower 4 and enters an ethylbenzene recovery tower 8; in the ethylbenzene recovery tower 8, the distillate at the top of the tower is taken as a refined ethylbenzene product of the unit, and the distillate at the bottom of the ethylbenzene recovery tower is sent to a polyethylbenzene recovery tower 9; the ethylbenzene and small amount of triethylbenzene are distilled from the top of the multi-ethylbenzene recovery tower 9, pressurized by a multi-ethylbenzene pressurizing pump 10 and fed into an anti-alkylation reaction system for transalkylation reaction, and a small amount of benzene extracted from the benzene discharge in the anti-alkylation reactor is mixed with the polyethylbenzene from the multi-ethylbenzene recovery tower, and then fed into an anti-alkylation reactor 11 for anti-alkylation reaction, so that the generated polyethylbenzene is converted into ethylbenzene again. And sending the residual oil of the bottom product of the anti-alkylation reactor to the outside.
As shown in fig. 1: in this embodiment, the alkylation reaction system is a low pressure drop reaction system, the feeding temperature of each two catalyst beds is controlled by steam pressure cascade with the steam generator 2, the operating pressure of the medium pressure steam generated by the steam generator 2 is 1.1MPaG in this embodiment, and the control temperature is 186 ℃.
As shown in fig. 1: in this embodiment, the ethylbenzene recovery tower 8 is designed to adopt a vacuum separation process, so that the temperature of the material in the bottom of the tower is controlled to about 170 ℃, and thus a reboiler in the bottom of the tower in the ethylbenzene recovery tower 8 can use 1.2MPaG steam generated by the steam generator 2 of the alkylation reaction system; the operation pressure of the ethylbenzene recovery tower 8 is 67KPa in the embodiment, and compared with the traditional operation pressure of 320KPa, the steam consumption of the reboiler at the kettle of the ethylbenzene recovery tower is reduced by 50% due to the increase of relative volatility; moreover, the reboiler at the bottom of the ethylbenzene recovery tower 8 is designed to use the medium-pressure steam generated by the steam generator 2 of the alkylation reaction system, the operation pressure is preferably 1.0-1.6 MPaG, a large amount of 4.0MPaG high-pressure steam does not need to be supplemented like the traditional process, the steam of the ethylbenzene device is comprehensively utilized and optimized, and the use amount of the 4.0MPaG high-pressure steam in the ethylbenzene recovery tower is reduced by 30% compared with the traditional process by adopting the process of the system of the embodiment.
Example 2: the energy-saving reaction process for producing ethylbenzene by pure ethylene is specifically applied to an ethylbenzene part of a 26 ten thousand ton/year ethylbenzene-styrene combined device, and specifically comprises the following steps: the alkylation reactor adopts an eight-bed vertical multi-section axial reactor, the normal operation flow of ethylene is 9160kg/h, the diameter of the reactor is designed to be phi 1800mm, the benzene-olefin ratio is controlled to be 3.0-3.5, the reaction temperature is 200-245 ℃, the outlet pressure of the reactor is controlled to be 3.0MPa, and the feeding temperature of a catalyst bed of the reactor adopts a mode of steam pressure cascade control with a steam generator. The alkylation reaction system only designs a set of safety valve system to meet the requirement, the inlet pressure of the alkylation reactor only needs 3.3MPa, and is reduced by 0.5MPa compared with the inlet pressure of 3.8MPa of the traditional reactor, and the power consumption of a corresponding circulating benzene pump, an ethylene compressor and the like is reduced by 160KW compared with the traditional process. The raw material benzene impurity treatment is carried out by pressurizing by a circulating benzene booster pump, the raw material benzene impurity passes through a protective reactor and then enters an alkylation reactor, the content of basic nitrogen in the material is less than 0.01PPM, the water content is controlled to be about 260PPM, the operation of the alkylation reaction system is stable, the selectivity of ethylbenzene reaches 90%, and the catalyst is not inactivated. 1.0MPaG medium pressure steam generated by a steam generator of the alkylation reaction system is used as a heat source for a reboiler of an ethylbenzene recovery tower, the operating pressure of the ethylbenzene recovery tower is 66KPa, and the steam consumption is 5.1t/h, which is reduced by 50 percent compared with the traditional process. By combining the technical measures, the total energy consumption of the ethylbenzene device designed by the patent reaches-10 kg standard oil/t ethylbenzene.
Claims (8)
1. An energy-saving reaction process for producing ethylbenzene by using pure ethylene is characterized by comprising the following steps:
a. treating raw material benzene: the method is characterized by comprising two impurity adsorbers I, two impurity adsorbers II, a light component removal tower and a benzene recovery tower, wherein raw material benzene is divided into two strands, and the first strand of raw material benzene is subjected to impurity removal through the impurity adsorber I and then returns to the top of the benzene recovery tower; the second strand of raw material benzene is dehydrated by a light component removal tower, and is returned to the top of the benzene recovery tower after impurity removal by the impurity absorber II; controlling the proportion of the first strand of raw material benzene to the second strand of raw material benzene to ensure that the water content of the benzene discharge at the top of the benzene recovery tower is 30-600 PPM;
b. protection reaction: the device is provided with an alkylation reactor and a protection reactor, and raw material ethylene is divided into alkylation reaction ethylene and a small amount of protection reaction ethylene; averagely dividing alkylation reaction ethylene into n parts, wherein the ethylene fraction n corresponds to the number of catalyst beds in an alkylation reactor; the protective reaction ethylene and the benzene discharged after temperature rise enter a protective reactor for protective adsorption reaction;
c. alkylation reaction: the device is provided with a steam generator, and each two layers of catalyst beds arranged in the alkylation reactor are correspondingly provided with one steam generator from the first catalyst bed; the protective reaction discharge and the first part of ethylene in the n parts of ethylene enter a first catalyst bed layer of an alkylation reactor for alkylation reaction; then adding one part of ethylene to carry out alkylation reaction before entering one catalyst bed layer normally; and the staged discharge formed after the reaction of each two catalyst bed layers enters a steam generator for heat exchange and then enters the next stage of alkylation reaction;
d. and (3) benzene recovery: the reaction material of the last stage formed from the top of the alkylation reactor enters a benzene recovery tower for benzene recovery and forms a benzene discharge together with the treated raw material benzene;
e. and (3) ethylbenzene recovery: an ethylbenzene recovery tower is arranged, and the produced material at the bottom of the benzene recovery tower enters the ethylbenzene recovery tower to recover ethylbenzene;
f. and (3) polyethylbenzene recovery: a polyethylbenzene recovery tower is arranged, and the material at the bottom of the ethylbenzene recovery tower enters the polyethylbenzene recovery tower to recover polyethylbenzene;
g. and (3) reverse alkylation reaction: and arranging an anti-alkylation reactor, extracting partial benzene from the benzene discharge material before temperature rise, and feeding the partial benzene and the polyethylbenzene recovered by the polyethylbenzene recovery tower into the anti-alkylation reactor for anti-alkylation reaction, wherein the reacted material is fed into the benzene recovery tower.
2. The energy efficient reaction process for producing ethylbenzene from pure ethylene according to claim 1, wherein: the benzene recovery tower is provided with a condenser, benzene discharge formed at the top of the benzene recovery tower is condensed by the condenser, and gas-phase benzene in the condensed benzene discharge enters the light component removal tower to be used as a heat source for maintaining the operation of the light component removal tower.
3. The energy-saving reaction process for producing ethylbenzene by using pure ethylene as claimed in claim 1, which is characterized in that: and (c) arranging a heat exchanger, wherein the first stage discharge formed in the step (c) enters the heat exchanger to exchange heat with the benzene discharge and then enters a corresponding steam generator.
4. The energy efficient reaction process for producing ethylbenzene from pure ethylene according to claim 1, wherein: the discharging temperature formed after the staged discharging formed in the step (c) passes through the steam generator is 200 ℃ to 210 ℃.
5. The energy efficient reaction process for the production of ethylbenzene from pure ethylene according to claim 1 or 4, wherein: the discharging temperature formed after the heat exchange of the steam generator is controlled in a steam pressure cascade mode with the steam generator, and the temperature of the steam generator for generating steam is not less than 180 ℃.
6. The energy efficient reaction process for producing ethylbenzene from pure ethylene according to claim 1, wherein: the protection reactor is internally provided with a protection catalyst with strong alkaline nitrogen adsorption capacity, and the alkaline nitrogen content in the protection reaction discharge material formed after the adsorption reaction of the protection reactor is less than 0.001 PPM.
7. The energy efficient reaction process for producing ethylbenzene from pure ethylene according to claim 5, wherein: the ethylbenzene recovery tower adopts a vacuum separation technology and is heated by steam formed by a steam generator.
8. The energy efficient reaction process for producing ethylbenzene from pure ethylene according to claim 1, wherein: the dosage of the small amount of the protective reaction ethylene is 1/3-3/4 of the dosage of each piece of ethylene entering each catalyst bed layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010500063.9A CN111574318B (en) | 2020-06-04 | 2020-06-04 | Energy-saving reaction process for producing ethylbenzene from pure ethylene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010500063.9A CN111574318B (en) | 2020-06-04 | 2020-06-04 | Energy-saving reaction process for producing ethylbenzene from pure ethylene |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111574318A CN111574318A (en) | 2020-08-25 |
| CN111574318B true CN111574318B (en) | 2022-09-30 |
Family
ID=72109841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010500063.9A Active CN111574318B (en) | 2020-06-04 | 2020-06-04 | Energy-saving reaction process for producing ethylbenzene from pure ethylene |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111574318B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115838315B (en) * | 2022-12-23 | 2023-11-17 | 常州瑞华化工工程技术股份有限公司 | Process for producing tert-butylethylbenzene by low aromatic alkene ratio and tert-butylethylbenzene |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1051166A (en) * | 1990-12-18 | 1991-05-08 | 中国石油化工总公司 | The ethylbenzene process process is produced in rare ethene and benzene reaction |
| CN1428319A (en) * | 2001-12-25 | 2003-07-09 | 中国石油化工股份有限公司 | Production method of alkylbenzene |
| CN1732138A (en) * | 2002-09-23 | 2006-02-08 | 埃克森美孚化学专利公司 | Alkylaromatics production |
| CN102906054A (en) * | 2010-03-10 | 2013-01-30 | 埃克森美孚化学专利公司 | Alkylated aromatics production |
| CN205635419U (en) * | 2016-05-24 | 2016-10-12 | 山东齐鲁石化工程有限公司 | Ethylene and benzene liquid phase method alkylation reaction system |
| CN107827692A (en) * | 2017-04-28 | 2018-03-23 | 常州瑞华化工工程技术有限公司 | A kind of method that ethylbenzene is produced with high concentration ethylene gas |
-
2020
- 2020-06-04 CN CN202010500063.9A patent/CN111574318B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1051166A (en) * | 1990-12-18 | 1991-05-08 | 中国石油化工总公司 | The ethylbenzene process process is produced in rare ethene and benzene reaction |
| CN1428319A (en) * | 2001-12-25 | 2003-07-09 | 中国石油化工股份有限公司 | Production method of alkylbenzene |
| CN1732138A (en) * | 2002-09-23 | 2006-02-08 | 埃克森美孚化学专利公司 | Alkylaromatics production |
| CN102906054A (en) * | 2010-03-10 | 2013-01-30 | 埃克森美孚化学专利公司 | Alkylated aromatics production |
| CN205635419U (en) * | 2016-05-24 | 2016-10-12 | 山东齐鲁石化工程有限公司 | Ethylene and benzene liquid phase method alkylation reaction system |
| CN107827692A (en) * | 2017-04-28 | 2018-03-23 | 常州瑞华化工工程技术有限公司 | A kind of method that ethylbenzene is produced with high concentration ethylene gas |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111574318A (en) | 2020-08-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101978028B (en) | Separation process for olefin production | |
| CN106588536B (en) | Preparation method and system of cyclohexanone | |
| CN107827692B (en) | Method for producing ethylbenzene by using high-concentration ethylene gas | |
| CN101703840A (en) | Four-effect rectification system for synthesizing leather dimethyl formamide solution by wet method and recovery method | |
| CN112321379B (en) | Energy-saving and environment-friendly method for preparing ethylbenzene from dry gas | |
| CN111574318B (en) | Energy-saving reaction process for producing ethylbenzene from pure ethylene | |
| KR20190042745A (en) | Integrated propane dehydrogenation process | |
| CN112745208B (en) | Cyclohexanone recovery and separation process and system | |
| CN105566030A (en) | Method for separating BTX | |
| CN102584518A (en) | Industrial production method and production device of isobutene | |
| CN111825513A (en) | Combined process and system for chemical-grade ethylene production and ethylbenzene production | |
| CN113845939B (en) | Novel process of absorption stabilizing unit and comprehensive utilization method of product thereof | |
| CN113480395B (en) | Flash separation process and device for preparing ethylbenzene from ethylene-rich gas | |
| CN115838315B (en) | Process for producing tert-butylethylbenzene by low aromatic alkene ratio and tert-butylethylbenzene | |
| CN111393249B (en) | Method for reducing ethylbenzene loss and energy consumption of ethylbenzene tower in ethylbenzene synthesis process | |
| CN220478148U (en) | Comprehensive utilization system for hydrogen in cyclohexanone device by esterification method | |
| CN1055912C (en) | Process for producing alkylbenzene | |
| CN112661597B (en) | Industrial production and regeneration method for preparing ethylbenzene from dry gas | |
| CN106608829B (en) | Ammonia recovery method in ethanol amine joint production process | |
| CN115304458B (en) | System and process for separating and refining acetaldehyde by ethanol dehydrogenation | |
| CN112961022B (en) | Separation device for synthesizing aromatic hydrocarbon product from methylbenzene and methanol | |
| CN217472748U (en) | 4-methyl-1-pentene separator | |
| CN114432724B (en) | Process system and method for isopropanol dehydration reaction and process system and method for preparing propylene from acetone | |
| CN103773498B (en) | The high temperature hydrogenation purification process of liquefied gas material | |
| CN105237320A (en) | Technology for preparing ethylbenzene by means of absorption and purification of high-pressure polyethylene tail gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |