CN1194948C - Method for producing styrene by catalytic dehydrogenation - Google Patents

Abstract

The present invention relates to a method for producing styrene from ethylbenzene catalytic dehydrogenation. Vapor is used for heating reaction effluent in a first stage and then is used as diluents of ethylbenzene. The method mainly solves the problem which exists in former production methods which are introduced by literatures that catalyst bed layer temperature changes too much in a reaction medium flow direction in a heat insulation bed reactor to influence the exerting of the performance of catalyst, reaction conversion rates and reaction yields. The present invention better solves the problem by adopting a technical scheme that at least one heating pipe is arranged in a fixed bed reactor bed layerand can be used in industrial production for preparing styrene from ethylbenzene dehydrogenation.

Description

The method of producing styrene by catalytic dehydrogenation

Technical field

The present invention relates to a kind of method of producing phenyl ethylene by ethyl benzene catalytic dehydrogenation.

Background technology

Vinylbenzene is widely used as production various kinds of resin, plastics and elastomeric raw material, extensively mainly being easy to polymerization (for example generating polystyrene) owing to vinylbenzene or carrying out the adaptability of copolymerization (for example producing rubber with butadiene copolymer) of its range of application.

Cinnamic production with regard to various catalyzer used in dehydrogenating technology and this technology, is all known.Main goal in research is to improve the benefit of this technology at present.Be known that the dehydrogenating technology method of ethylbenzene especially, wherein dehydrogenation a cover comprise two placed in-line dehydrogenation reactors at least and place between the reactor, reaction effluent and vapor generation heat exchange therein and heated heating unit carries out.According to this technology, steam at first is used for the reacting by heating effluent, mixes with ethylbenzene in the ingress of first reactor then.The operational condition that this technology adopted is that the same 1 mole of ethylbenzene of 3 to 10 moles steam is mixed, and the ingress temperature and pressure of first reactor is respectively 550～680 ℃ and 0.04～0.1MPa (absolute pressure).The temperature and pressure condition at other reactor inlet place is respectively 550～680 ℃ and 0.02～0.08MPa (absolute pressure), and total air speed of ethylbenzene is equal to or greater than 0.15 hour ^-1Total air speed of ethylbenzene is meant the ratio of the volumetric flow rate of ethylbenzene with the cumulative volume of catalyzer.By this technology, conversion of ethylbenzene is approximately greater than 65～75%, even higher, and reaches the mole selectivity greater than 94%.But after for some time, the carrying out of this technology can cause the reduction of selectivity of styrene and conversion of ethylbenzene, but this reduction can be limited through improving temperature of reaction.In fact, it is aging gradually to observe catalyzer after for some time, occurs carbon laydown on catalyzer.This is because the focus that exists along production line (especially in middle heating unit) causes thermal degradation reaction, can produce heavy compounds.It is calculated that the ratio of formed heavy product is about 17000PPm in effusive hydrocarbon polymer per ton, even more.As a result, cause that thus loss of material increases, catalyst efficiency reduces, thereby need clean continually.In order to eliminate the shortcoming of this technology, a kind of process for manufacturing styrene is disclosed among the document CN1006061B.Or rather, it is a kind of processing method through producing phenyl ethylene by ethyl benzene catalytic dehydrogenation.By this method, dehydrogenation comprises in three placed in-line fixed bed dehydrogenation reactors at a cover carries out, and settles one or more heating units between reactor.In well heater, reaction effluent and vapor generation heat exchange and be heated, steam is used for the reacting by heating effluent in the fs, mixes with ethylbenzene in the first dehydrogenation reactor ingress in subordinate phase.According to this invention, this processing method is characterised in that:

Ethylbenzene with steam with steam: ethylbenzene is that the molar ratio between 5: 1 and 13: 1 mixes, in the ingress of above-mentioned each reactor with the temperature of mixture heating up to 580 between to 645 ℃.Mean pressure in first reactor is with absolute manometer, and between 0.06～0.1MPa, in the second and the 3rd reactor, pressure remains between 0.04～0.07MPa with absolute manometer, and the total air speed of the liquid ethylbenzene of Cai Yonging was at 0.20 and 0.35 hour simultaneously ^-1Between.

This processing method thinks that the various radial reactors of type are preferable described in the employing French Patent FR2365370.Because there is bad adaptability in the radial mode reactor, the easy big area of catalyzer is poisoned, and catalyst life is vulnerable to influence.Simultaneously since catalyst basket generally up to 10 meters, the fluid distribution technical requirements is very high, the outer gap that distributes between tube and the cylindrical shell is difficult to reach design requirements when installing, and promotes the use of and can cause difficulty.In order to solve the defective that the radial reactor reaction process exists, a kind of diameter of axle is disclosed among the document CN86200368U to cold-tube type ammonia synthesis converter catalyst basket, it is that beds is divided into axial direction part and radial section, wherein axial direction part be positioned at radial section above, the top cover that is about to reaction bed is opened or perforate.This reactor process, because an axial direction part is arranged at reactor catalyst bed top, so that when the obnoxious flavour composition is higher, can play a filteration, can avoid the catalyzer big area to poison, it is big to have kept radial reactor throughput simultaneously, the advantage that net value is high.Increase the molecule thermo-negative reaction owing to ethyl benzene dehydrogenation preparation of styrene is one, wish that therefore the beds pressure drop is wanted little and condition of negative pressure is operated down, make reaction carry out and to improve throughput towards purpose product vinylbenzene direction.The characteristics of this reaction wish that more reaction medium streamwise in beds changes as far as possible little on the other hand, the performance of catalyzer can be not fully exerted, improve reaction conversion ratio and reaction yield simultaneously, how not keep the little problem of rangeability but above-mentioned document relates to temperature.

A kind of catalyticreactor of two-stage dehydrogenation reaction has been described in the document U.S. Pat 3918918.This reactor has the catalytic bed of an integral body, by the sealed structure in the catalytic bed catalytic bed is divided into two sections, and this reactor has also comprised an inlet feed mixing tank and an intersegmental reheater.This reactor has characteristics such as thermal expansion reasonable in design, pressure drop are little, but owing to adopt the two-stage adiabatic reaction, has limited the further raising of catalyst reaction performance.

A kind of novel radial reactor that is used for ethyl benzene dehydrogenation preparation of styrene has been described in document European patent EP 0724906A1 and the U.S. Pat 5358698.Be provided with specific plate washer and reduce the ununiformity that reactant flow circumferentially distributes in this Reactor inlet pipe, the center director by optimization design obtains uniform reactor bed flow velocity, thereby optimizes reactivity worth.But still adopt the adiabatic catalytic bed, make reaction effect further improve and be restricted.

Draw after deliberation, in adiabatic heat absorption type reaction process, influence reaction conversion ratio and optionally principal element be temperature.Certainly pressure also has material impact to reaction conversion ratio and selectivity, but in negative dehydrogenation technology commonly used, the variable range of pressure is very little, the restriction of the pressure of machine suction port and system pressure drop by compression, and general reactor exit absolute pressure is 40kPa.0.35～0.5 meter of the liquid air of Ethylbenzene Dehydrogenation Reactor design at present speed ³Ethylbenzene/rice ³Under the condition of catalyzer hour, the reactor outlet material composition also has certain distance from the molecular balance composition, limited reactions further carries out and the reason that continues to improve transformation efficiency is that thermo-negative reaction makes temperature of reaction fall too lowly, and make speed of reaction slow excessively, thereby make reaction " being freezed ".

Summary of the invention

Technical problem to be solved by this invention is to overcome in the past that ethylbenzene dehydrogenation reaction adopts the adiabatic reactor reactor in the document, reaction bed temperature changes excessive along the reaction medium flow direction, influence the problem of catalyst performance performance and reaction conversion ratio and reaction yield, and a kind of method of new producing phenyl ethylene by ethyl benzene catalytic dehydrogenation is provided.The reactor that uses in this method has reaction bed temperature than homogeneous, and can better eliminate the characteristics of catalyzer local bed high-temperature zone and raising reaction conversion ratio and yield.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of method of producing phenyl ethylene by ethyl benzene catalytic dehydrogenation, dehydrogenation comprises in two placed in-line dehydrogenation reactors at a cover at least carries out, settle one or more heating units between the reactor, reaction effluent carries out heat exchange with steam and is heated in heating unit, steam is used for the reacting by heating effluent in the fs, and mix with ethylbenzene in the ingress of first dehydrogenation reactor in subordinate phase, with the steam between 5: 1～13: 1: the ethylbenzene molar ratio mixes, mixture is heated to the temperature between 550～645 ℃ at described each reactor inlet place, absolute pressure mean value in first reactor is at 0.04～0.1MPa, second and remain on 0.03～0.08MPa with the absolute pressure mean value in the post-reactor, adopted simultaneously 0.15～0.55 hour ^-1Between the total air speed of liquid ethylbenzene, wherein at least the first reactor adopts following fixed-bed reactor, this reactor comprises a housing that can bear pressure, feed-pipe, discharge nozzle, inside distributor, outer tube and first base plate of distributing, its middle shell is by cylindrical tube, upper cover and lower cover are formed, inside distributor and the outer tube that distributes are coaxial and form a catalyst basket with cylindrical tube, inside distributor and the outer tube that distributes have aperture in the catalyst basket corresponding section, first base plate links to each other with the outer bottom that distributes tube with inside distributor respectively, leaving the space between outer distribute tube and the cylindrical tube is connected with the discharging mouth of pipe, wherein reactor also comprises at least one thermal barrier import, at least one heating medium outlet, second base plate and at least one heating tube under first base plate, form first enclosed chamber between first base plate and second base plate, form second enclosed chamber between second base plate and the lower cover, two ports of heating tube are connected with first enclosed chamber and second enclosed chamber respectively, and go deep into whole catalyst basket, thermal barrier import and heating medium outlet respectively with first enclosed chamber and second enclosed chamber in one be connected, reheater is made up of 2～2000 heating tubes, on the same radial section of catalyst basket, be evenly distributed, and coaxial with cylindrical tube.

In the technique scheme, a upper cover being arranged on the reactor catalysis bed or do not have upper cover is the various ways such as upper cover that aperture was opened wide or had at the catalytic bed top fully.If the reactor catalysis bed has upper cover, upper cover links to each other with the outer top that distributes tube with inside distributor respectively, to form radial flow.If reactor does not have upper cover or upper cover has many apertures, and the inseparable aperture of corresponding axial direction part portion of the inside and outside tube that distributes, the length of aperture area is not unequal, distributes that aperture area length is not bigger for tube outward usually, to form the diameter of axle to flowing.If the upper cover perforate, then the size of aperture is not blown to good with the catalyzer in the catalyst basket.The preferable range of thermal barrier import volume is 1, and the preferable range of heating medium outlet quantity is 1.The preferable range of heating tube quantity is 100～500.Heating tube pattern preferred version is an inverted-loop tube or/and two sleeve pipe, and heating tube pattern more preferably scheme is an inverted-loop tube or/and two sleeve pipe, and the outer porous material aerial construction that adopts of its pipe, and porous material is selected from wire cloth, porous plate or Johnson's net.

According to a preferable embodiment of the inventive method, the total air speed of the liquid ethylbenzene of employing was at 0.25～0.45 hour ^-1Between.

The temperature at each reactor inlet place is preferable to remain between 600～640 ℃.

Good further is, in first reactor mean pressure with absolute manometer, between 0.06～0.08MPa, second and with the mean pressure in the post-reactor with absolute manometer between 0.04～0.07MPa.

Good further is the steam that adopts between 7: 1 and 13: 1: the ethylbenzene molar ratio, the transformation efficiency of ethylbenzene and mole selectivity are higher in this scope.

The inventive method can adopt the catalyzer that is generally used for ethylbenzene dehydrogenation.With the ferric oxide is the catalyzer of base stock, particularly contains can mentioning especially of molybdenum.

The method according to this invention under moderate temperature conditions, and is carried out under low pressure and low liquid ethylbenzene gross space speed, can limit the formation of heavy degraded product significantly.In fact, according to method of the present invention, formed heavy product ratio, effusive hydrocarbon polymer per ton is no more than 5000PPm.

According to method of the present invention, conversion of ethylbenzene can improve, and selectivity is about 96% or higher.

The present invention adopts the fixed-bed reactor after the improvement, and when in the reactor during not perforate of upper cover, reactor is a radial reactor.When removing upper cover or upper cover and have many apertures, reactor is an axial-radial flow reactor, helps making full use of of catalyzer in the beds, is beneficial to improve reactor throughput.Heating tube is set in catalyst basket, makes heating tube carry out heat exchange, help reacting the reaction mass raising temperature of back cooling, reach the purpose that helps reacting with reactor catalysis bed reactant flow.Heating tube is evenly distributed on the same radial section of catalyst basket, and coaxial with cylindrical tube, make whole beds reach the temperature homogeneous as much as possible.Heating tube is designed to inverted-loop tube or/and two sleeve pipe, makes in the catalyst bed reaction medium and heat exchange component carry out cross-flow and conduct heat, higher heat-transfer effect is arranged to reach.The upcast of inverted-loop tube and the fluid temperature (F.T.) of downtake compensate mutually, make that vertically heat exchange effect everywhere is consistent to a great extent, thereby guarantee distribute vertically homogeneity of catalytic bed temperature; In two sleeve pipes, the heat hot carrier at first enters two telescopic pipe cores, and this moment elevated temperature heat carrier and heat exchange of low temperature thermal barrier enters annular space then to keep its thermal barrier temperature, reaches the purpose of heating bed.Because the low temperature thermal barrier complementary heat-exchanging of two sleeve pipe pipe core higher temperature carriers and annular space, thereby can guarantee the homogeneity that the catalytic bed axial temperature distributes; Or/and the built on stilts members of porous material such as two telescopic periphery kalamein silk screen, porous plate or Johnson's net are isolated the heater and the catalyzer of high wall temperature, avoided the directly heating tube of the high wall temperature of contact of catalyzer at inverted-loop tube.Though the catalytic amount of heating tube periphery is few, account for 5/10000ths of total amount, can avoid the too high caused side reaction of local temperature thus.Adopt technical scheme of the present invention in addition, because the heat carrier flow in the heating tube, temperature can be regulated, thereby can make radially bed temperature trend homogeneous everywhere.Adopt technical scheme of the present invention to be used for ethylbenzene dehydrogenation reaction and compare homogeneous through the evidence reaction bed temperature, can be near waiting hotbed.Use same catalyzer, the single reaction vessel reaction conversion ratio is the highest to be improved approximately 7.6%, and it is nearly 6.7% that purpose product vinylbenzene yield can improve, and obtained better technical effect.

Description of drawings

Fig. 1 is a radial fixed-bed dehydrogenation reactor synoptic diagram of the present invention.

Fig. 2 is that the diameter of axle of the present invention is to the fixed bed dehydrogenation reactor synoptic diagram.

Fig. 3 is that reactor radial section heating tube is arranged synoptic diagram.

Fig. 4 is a styrene Production schematic flow sheet of the present invention.

Among Fig. 1, Fig. 2 or Fig. 3,1 is upper cover, and 2 is cylindrical tube, 3 is heating medium outlet, and 4 is the thermal barrier import, and 5 is lower cover, 6 is end socket, and 7 is second base plate, and 8 is first base plate, 9 is beds, 10 is inside distributor, and 11 is heating tube, and 12 is the outer tube that distributes, 13 is Reactor inlet, and 14 is reactor outlet.

The below introduces embodiment of the present invention and better understands the present invention. These embodiments provide in the mode of statement, there is no the meaning of limiting protecting scope, and realize with the production of styrene flow process of above-mentioned Fig. 3.

Reactor has a housing that bears pressure among Fig. 1, and this housing is comprised of cylindrical tube 2, upper cover 1 and low head 5. Respond on the housing import 13 and the reactor outlet 14 of device, housing also has a heat carrier import 4 and a heating medium outlet 3. Have in the housing two with cylindrical tube 2 coaxial, columniform inside distributor 10 and outer distributing barrel 12, they and first base plate 8 are by formation catalyst basket mechanically coupled together, thus catalyst filling formation beds 9 in the catalyst basket. In the appropriate location of catalytic bed, at least one heating tube 11 is set. This heating tube can be inverted-loop tube or/and two sleeve pipe is coaxial with reactor cylindrical tube 2 and beds 9. The perforate end original position of inside distributor 10 and the position of opening initiating terminal position of outer distributing barrel 12 can equate also can be unequal, if equate and have the upper cover of atresia, then consists of radial reactor, as shown in Figure 1; If position of opening is unequal and catalytic bed is opened wide or the upper cover of perforate is arranged, then consist of axial-radial flow reactor, as shown in Figure 2.

The flow direction of gas reaction medium in this reactor is such. Reactant enters the central passage that is formed by inside distributor 10 by Reactor inlet 13, and the simultaneously part shunting of flowing in central passage enters beds 9. Enter the gas of beds mainly with radially by bed, contact simultaneously the generation conversion reaction with catalyst. Because the fuel factor of reaction, gas temperature descends after the reaction, and the gas after the cooling continues radially to flow, until conduct heat with heating tube generation cross-flow. Reacting gas is heated by high-temperature heat carrier and the temperature rising, so that reaction is carried out at faster speed. Reacted gas flows out beds 9, converges in the confluence passage that is made of outer distributing barrel 12 and cylindrical tube 2, finally by reactor outlet 14 outflow reactors.

The flow direction of heat carrier in heating tube is such: the heat carrier of high temperature enters the second sealing chamber that is made of second base plate 7 and end socket 6 by heating tube import 4, evenly distributes, enters in the pipe of each heating tube 11 by the second sealing chamber high-temperature heat carrier. This heating tube 11 be inverted-loop tube or/and two sleeve pipe is coaxial with reactor cylindrical tube 2 and beds 9, thereby guaranteed the circumferential uniformity of bed temperature after the heating. The heat carrier that flows out from the pipe of each heating tube 11 is pooled to the first sealing chamber that the not perforate section by second base plate 7, first base plate 8 and outer distributing barrel 12 consists of, and by heating medium outlet 3 outflow reactors.

Heating tube adopts inverted-loop tube or/and two sleeve pipe. Adopt inverted-loop tube or/and two sleeve pipe mainly is in order to eliminate the axial temperature difference of catalytic bed. Heat carrier temperature in inverted-loop tube in the down-comer of tedge compensates mutually, and both mean temperatures are little along the variation of pipe range, thereby guarantees the vertically uniformity of temperature of heating rear catalyst bed. High-temperature heat carrier at first enters central tube in two sleeve pipes, then flows out two sleeve pipes through annular space. Because the heat carrier of higher temperature will heat the lower heat carrier of annular space temperature in the central tube, keeping annular space heat carrier temperature, thus the assurance catalytic bed uniformity of temperature vertically.

Heating tube adopts inverted-loop tube or/and two sleeve pipe, for avoiding high wall temperature on the impact of catalytic reaction, adopt porous material aerial construction outside pipe, avoid catalyst directly to contact tube wall, this porous material can adopt the materials such as woven wire, porous plate or Johnson Net.

The especially applicable ethyl benzene dehydrogenation preparation of styrene technique of this type of reactor can be used for new device and will former many thermal insulation, intersegmental reheat-type reactor be improved in the separate unit catalytic bed with the fixed bed reactors of heat-exchanging tube bundle, strengthens and produces, the saving equipment investment; The Revamping that can be used for existing apparatus can increase heating tube in original radial reactor or axial-radial flow reactor catalytic bed.

According to the present invention, the equipment shown in Fig. 4 comprises at least two dehydrogenation reactors that are installed in series 15 and 16.

Ethylbenzene is vaporized in a heat exchanger (not shown) first, enters stove 5 by pipeline 4, enters stove 7 by pipeline 6 afterwards, and then ethylbenzene enters in the blender 9 by pipeline 8, in this same vapor mixing. The water of having vaporized in evaporimeter (Fig. 3 is not shown) in advance carries out a series of heat exchange by pipeline 10 input stoves 7. In the exit of stove 7, steam is imported in the heat exchanger 11, the effluent heating that produces from reactor 2, steam is then by pipeline 12 input stoves 13, be heated at this, then steam is by pipeline 14 input heat exchangers 15, the in the future effluent of autoreactor 1 heating. Steam, in pipeline 18 injecting mixers 9, mixes with ethylbenzene at this after this is heated again by pipeline 16 input stoves 17 afterwards. Ethylbenzene/when the steam reaction mixture left blender 9, temperature was about 550～645 ℃. According to the present invention, steam in the mixture: the molar ratio of ethylbenzene is between 5 and 13.

The reactant mixture that forms like this is injected into reactor 1 by pipeline 19, and mixture is by radial section and axial direction part catalytic bed in this reactor. The pressure of this reactor must be adjusted to average pressure and be 0.04～0.1MPa (with absolute manometer), and is better with 0.06 to 0.08MPa. From reactor 1 out the time, reactant mixture or effluent heat by pipeline 20 inflow heat exchangers 15. Since the endothermic character of dehydrogenation reaction, the tens of degree of the drop in temperature of mixture in dehydrogenation reactor 1 and 2. According to the present invention helpful be that reaction effluent respectively before the injecting reactor 2, is made it heating in heat exchanger 15 and 11. When flowing out from interchanger 15, the temperature of reactant mixture is enough to again carry out dehydrogenation under the temperature between 550 to 645 ℃. Therefore, effluent is by pipeline 21 inflow reactors 2, and in this reactor, effluent is by beds, and the pressure of reactor must be adjusted to average pressure and be 0.03～0.08MPa (with absolute manometer), and is better with 0.04～0.065MPa. When flowing out from reactor 2, effluent carries out heat exchange by pipeline 22 input heat exchangers 11, then draws by pipeline 23, flows into energy recycle device (not marking among Fig. 3).

Reactor 1 and 2 and later reactor in, the liquid ethylbenzene air speed is 0.15～0.55 hour^-1, and at 0.25～0.45 hour^-1Between better.

For obtaining better distribution of gas effect, the gas distributor of back taper can also be installed in the inside distributor in Fig. 1 or Fig. 2. Inside distributor, outer distributing barrel have the aperture of suitable size according to the needs that react. The height of axial direction part is generally 40～2000 millimeters, and better height is generally 500～1000 millimeters. Need not the special seal device between axial direction part and the radial section, simple in structure.

The present invention is further elaborated below by embodiment.

Specific implementation method

[embodiment 1]

The catalytic dehydrogenation of ethylbenzene/vapour mixture is carried out with a set of equipment, and it produces the block diagram signal as Fig. 4.First reactor and second reactor all adopt the reactor of Fig. 1 or Fig. 2, and the catalyzer of use adopts iron one potassium one cerium one molybdenum system.Reactor inside distributor diameter is 1150 millimeters, and the bed radial thickness is 600 millimeters, and static total height is 5500 millimeters.Reactor adopts upper cover to have the axial-radial flow reactor form of many apertures, and heating tube adopts inverted-loop tube, gos deep into whole beds, and the heating tube quantity of each reactor is 100, is uniformly distributed on the radial section logical thermal barrier in the inverted-loop tube.The temperature that reaction mass advances first reactor is 620 ℃, pressure is 58KPa, total flux is 32257.2 kilograms/hour, the reaction effluent temperature is 547.6 ℃, the geometrical dimension of second reactor is with first reactor, the second reactor content inlet temperature is 625 ℃, and the reaction effluent temperature is 582 ℃ of homogeneous, and the reaction result of first reactor and second reactor sees Table 1 and table 2 respectively.

[comparative example 1]

The reactor geometrical dimension is with embodiment 1, and catalyzer and reaction process condition are not according to the dress heating tube in the reactor among Fig. 1 with embodiment 1.After reaction for some time, the reaction result of first reactor and second reactor sees Table 1 and table 2 respectively.

[embodiment 2]

Press condition and the step of embodiment 1, just change the heating tube pattern and be two sleeve pipes, two sleeve pipe quantity are 500, the first reactor outlet temperature is 550.9 ℃ of homogeneous, reaction result is: conversion of ethylbenzene is 48.11%, and selectivity of styrene is 96.0%, and the vinylbenzene yield is 46.2%.The second reactor outlet temperature is 585.5 ℃ of homogeneous, and conversion of ethylbenzene is 49.8%.

[embodiment 3]

Press condition and the step of embodiment 1, just changing the heating tube pattern is inverted-loop tube and each 300 of two sleeve pipes, and the first reactor outlet temperature is 545.3 ℃ near homogeneous, and reaction result is: conversion of ethylbenzene is 44.15%, selectivity of styrene is 97.2%, and the vinylbenzene yield is 42.9%.The second reactor outlet temperature is 581.3 ℃ near homogeneous, and conversion of ethylbenzene is 47.5%.

The table 1 first dehydrogenation reactor reaction result

Component	Reactor feed		Embodiment 1		Comparative example 1
							The flow kilogram/hour	Form % weight	The flow kilogram/hour	Form % weight	The flow kilogram/hour	Form % weight
	Ethylbenzene	13138	40.73	7854.1	24.34	7924.6							24.56
Vinylbenzene							98.7	0.31	5157.4	15.98	5089.9	15.77
	Temperature, ℃	620		547.6		542.0
Pressure, kPaA								58		52		52
	Conversion of ethylbenzene, %			46.7		40.52
Selectivity of styrene, %								97.0		97.5
			The vinylbenzene yield, %			45.3						39.5

The table 2 second dehydrogenation reactor reaction result

Component	Reactor feed		Embodiment 1		Comparative example 1
							The flow kilogram/hour	Form % weight	The flow kilogram/hour	Form % weight	The flow kilogram/hour	Form % weight
	Ethylbenzene			4598.6	14.25	4639.9							14.38
Vinylbenzene									8210.3	25.45	8170.2	25.32
	Temperature, ℃	625		582		542.0
Pressure, kPaA								47		42		42
	Conversion of ethylbenzene, %			47.9		41.45

Claims (7)

1, a kind of method of producing phenyl ethylene by ethyl benzene catalytic dehydrogenation, dehydrogenation comprises in two placed in-line dehydrogenation reactors at a cover at least carries out, settle one or more heating units between the reactor, reaction effluent carries out heat exchange with steam and is heated in heating unit, steam is used for the reacting by heating effluent in the fs, and mix with ethylbenzene in the ingress of first dehydrogenation reactor in subordinate phase, with the steam between 5: 1～13: 1: the ethylbenzene molar ratio mixes, mixture is heated to the temperature between 550～645 ℃ at described each reactor inlet place, absolute pressure mean value in first reactor is at 0.04～0.1MPa, second and remain on 0.03～0.08MPa with the absolute pressure mean value in the post-reactor, adopted simultaneously 0.15～0.55 hour ^-1Between the total air speed of liquid ethylbenzene, it is characterized in that at least the first reactor adopts following fixed-bed reactor, this reactor comprises a housing that can bear pressure, feed-pipe, discharge nozzle, inside distributor, outer tube and first base plate of distributing, its middle shell is by cylindrical tube, upper cover and lower cover are formed, inside distributor and the outer tube that distributes are coaxial and form a catalyst basket with cylindrical tube, inside distributor and the outer tube that distributes have aperture in the catalyst basket corresponding section, first base plate links to each other with the outer bottom that distributes tube with inside distributor respectively, leaving the space between outer distribute tube and the cylindrical tube is connected with the discharging mouth of pipe, wherein reactor also comprises at least one thermal barrier import, at least one heating medium outlet, second base plate and at least one heating tube under first base plate, form first enclosed chamber between first base plate and second base plate, form second enclosed chamber between second base plate and the lower cover, two ports of heating tube are connected with first enclosed chamber and second enclosed chamber respectively, and go deep into whole catalyst basket, thermal barrier import and heating medium outlet respectively with first enclosed chamber and second enclosed chamber in one be connected, reheater is made up of 2～2000 heating tubes, on the same radial section of catalyst basket, be evenly distributed, and coaxial with cylindrical tube.

2, according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1, it is characterized in that also comprising a upper cover on the catalytic bed in the reactor, upper cover links to each other with the outer top that distributes tube with inside distributor respectively, and upper cover is not perforate.And inside distributor communicates with the feed-pipe that gos deep into upper cover.

3,, it is characterized in that the top of catalytic bed is unlimited fully according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1; Or have a capping that has many apertures.

4,, it is characterized in that the thermal barrier import is 1 according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1.

5,, it is characterized in that heating medium outlet is 1 according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1.

6,, it is characterized in that reheater is made up of 100～500 heating tubes according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1.

7,, it is characterized in that heating tube is that inverted-loop tube is or/and two sleeve pipe according to the method for the described producing phenyl ethylene by ethyl benzene catalytic dehydrogenation of claim 1.

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