CN103360194A - Hexane recovery method - Google Patents
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- CN103360194A CN103360194A CN2012103899320A CN201210389932A CN103360194A CN 103360194 A CN103360194 A CN 103360194A CN 2012103899320 A CN2012103899320 A CN 2012103899320A CN 201210389932 A CN201210389932 A CN 201210389932A CN 103360194 A CN103360194 A CN 103360194A
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Abstract
The invention provides a hexane recovery method which comprises the following steps: evaporating a material stream containing water, low polymers and hexane in an evaporation region to obtain a gas-phase material stream containing water and hexane; carrying out heat exchange on the gas-phase material stream in a heat exchange region to obtain a temperature-reduced heat-exchanged material stream; and carrying out azeotropic distillation on the heat-exchanged material stream in a dehydration region to obtain a hexane material stream and a hexane/water gas-phase mixture material stream, wherein the temperature of the heat-exchanged material stream is T1, the temperature of the hexane/water gas-phase mixture material stream formed in the dehydration region is T2, and the following heat exchange conditions are satisfied in the heat exchange region: T2 is greater than T2, and the difference between T2 and T1 is greater than 0, but not greater than 20 DEG C. The method fully utilizes the heat carried by the gas-phase material stream obtained in the evaporation region, thereby lowering the consumption of low-pressure steam and circulating cooling water, and obviously lowering the heat load of the dehydration region.
Description
Technical field
The present invention relates to a kind of Recycling hexane method, particularly, the present invention relates to a kind of method that from the mixture that contains oligopolymer, water and hexane, reclaims hexane.
Background technology
(that is, be the high and nonpolar thermoplastic resin of a kind of degree of crystallinity HDPE), purposes is very extensive for high density polyethylene(HDPE).One of production technique that high density polyethylene(HDPE) is the most frequently used is slurry polymerization processes, and its main flow process is in the presence of as the hydrogen of molecular weight regulator, and ethene is contacted with catalyst system in thinner (being generally hexane) with alpha-olefin, carries out polymerization; After removing in the mixture that polymerization obtains unreacted monomer and hydrogen, carry out solid-liquid separation, obtain being the polyolefine of solid phase and the liquid phase that is mainly thinner, isolated thinner carries out recycling behind the purifying from this liquid phase.For example: the preparation method of the disclosed superfine polyethylene powder of CN102002124A.
Because in the existing slurry polymerization processes, thinner recycles usually, therefore need to reclaim and purifying thinner (mainly being oligopolymer and the water that will remove in the thinner) energy-efficiently.Take hexane as thinner as example, as shown in Figure 1, present Recycling hexane is generally with the purifying flow process: that will separate polyolefin products contains water take hexane as main body, the logistics 8 of oligopolymer and hexane is evaporated in evaporator tower 1, isolate residue 9(and be mainly oligopolymer), the gaseous stream that contains water and hexane 10 that obtains of evaporation carries out condensation with recirculated cooling water in interchanger 24 after, send into and carry out oily water separation in the knockout drum 4, isolate not condensate 19 and water logistics 23, the oil phase logistics 20 that obtains sent into carry out component distillation in the dehydration tower 7 to remove water, at the bottom of the tower of dehydration tower 7, obtain hexane streams 14, the hexane that obtains from the cat head of dehydration tower 7 and the gas phase mixture logistics 13 of water are carried out condensation with recirculated cooling water interchanger 24 after, the condensation product that obtains sent into carry out oily water separation in the knockout drum 4, isolate not condensate 19 and water logistics 23.Wherein, will be at the bottom of dehydration tower 7 towers part 15 of the hexane streams 14 of output interchanger 25 with after the low-pressure steam heating, the hexane streams 17 that temperature raises is sent in the dehydration tower 7 as the heating medium that boils again; Export behind another part 16 usefulness circulating cooling water for cooling of hexane streams 14.
Summary of the invention
The present inventor finds in research process, and when adopting existing technique to reclaim hexane, the gaseous stream that contains on the one hand water and hexane repeatedly cools off and heats, and has consumed low-pressure steam and recirculated cooling water; On the other hand condensed logistics is sent into when carrying out component distillation in the dehydration tower, because the charging of supercooled liquid phase also can cause hexane dehydration tower tower reactor thermal load to increase.
The object of the invention is to overcome the problems referred to above that prior art exists, a kind of Recycling hexane method is provided, the method not only can reduce the consumption of low-pressure steam and recirculated cooling water, and can reduce the thermal load of dehydration tower tower reactor.
The invention provides a kind of Recycling hexane method, the method comprises:
The logistics that will contain water, oligopolymer and hexane is evaporated in evaporating area, obtains containing the gaseous stream of water and hexane;
Described gaseous stream is carried out heat exchange in heat transfer zone, obtain logistics after the heat exchange that temperature reduces;
Component distillation is carried out in logistics after the described heat exchange in drying zone, obtain the gas phase mixture logistics of hexane streams and hexane and water;
Wherein, the temperature of logistics is T after the described heat exchange
1, this logistics forms the gas phase mixture logistics of described hexane and water in described drying zone temperature is T
2, the heat transfer boundary condition of described heat transfer zone so that: T
2＞T
1, and T
2With T
1Between difference for greater than 0 and be not higher than 20 ℃.
It is to be lower than the azeotropic temperature of this logistics in drying zone (namely that the gaseous stream that the method according to this invention obtains evaporating area is cooled to temperature, form the temperature of the gas phase mixture logistics of hexane and water by component distillation), and and the difference between the azeotropic temperature is not for being higher than 20 ℃, take full advantage of on the one hand the heat that gaseous stream that evaporating area obtains carries, reduced the consumption of low-pressure steam and recirculated cooling water; Significantly reduced on the other hand the thermal load of drying zone.
Description of drawings
Fig. 1 is the Recycling hexane method of using in the present manufacture of polyolefins technique; And
Fig. 2 is preferred embodiment a kind of according to Recycling hexane method of the present invention.
Embodiment
The invention provides a kind of Recycling hexane method, the method comprises: the logistics that will contain water, oligopolymer and hexane is evaporated in evaporating area, obtains containing the gaseous stream of water and hexane;
Described gaseous stream is carried out heat exchange in heat transfer zone, obtain logistics after the heat exchange that temperature reduces;
Component distillation is carried out in logistics after the described heat exchange in drying zone, obtain the gas phase mixture logistics of hexane streams and hexane and water.
The method according to this invention, the temperature of logistics is T after the described heat exchange
1, this logistics forms the gas phase mixture logistics (that is, the azeotrope of hexane and water) of hexane and water in described drying zone temperature is T
2, the heat transfer boundary condition of described heat transfer zone so that: T
2＞T
1, and T
2With T
1Between difference for greater than 0 and be not higher than 20 ℃.Not only can reduce like this amount of recirculated cooling water that the gaseous stream that contains water and hexane is cooled off, even eliminate the demand for recirculated cooling water, take full advantage of the heat that the gaseous stream that contains water and hexane that comes from evaporating area carries; And can significantly reduce the thermal load that drying zone is produced owing to crossing cold feed.Come from the utilization ratio of the heat that the gaseous stream that contains water and hexane of evaporating area carries from further raising, further reduce the angle of the thermal load that drying zone is produced and set out T
2With T
1Between difference be preferably more than 0 and be not higher than 15 ℃, more preferably 5-15 ℃.
Can come so that the temperature of the logistics after the heat exchange satisfies previously described requirement by the heat transfer boundary condition of regulating heat transfer zone.
In one embodiment of the invention, the method of described gaseous stream being carried out heat exchange in heat transfer zone comprises: the part of the hexane streams that drying zone is obtained is sent into the hexane streams that the temperature that obtains raises in the described drying zone as the heating medium that boils again again as heat transferring medium and described gaseous stream heat exchange.The temperature of the hexane streams that obtains from drying zone is to be lower than the gaseous stream that contains water and hexane that obtains from evaporating area, a part of hexane streams and the described gaseous stream that contains water and hexane are carried out heat exchange in heat transfer zone, can reduce the temperature of the gaseous stream that contains water and hexane, and described gaseous stream can also replace part or all of low-pressure steam, be used for improving the temperature of carrying out this part hexane streams of heat exchange with this gaseous stream, this part hexane streams can be sent in the drying zone as the heating medium that boils again.
In this embodiment, can adopt various heat exchange modes commonly used to contain the gaseous stream of water and hexane and the part of described hexane streams is carried out heat exchange with described, be not particularly limited.For example: can be in various interchanger commonly used contain the gaseous stream of water and hexane and the part of described hexane streams is carried out heat exchange with described.
Can determine amount as the hexane streams of heat transferring medium with the amount of heating medium according to boiling again of drying zone needs.Usually, the weight ratio of the part of described hexane streams and described hexane streams is 0.1-0.9:1.Preferably, the weight ratio of the part of described hexane streams and described hexane streams is 0.75-0.85:1.
The method according to this invention, the temperature of the logistics after carrying out heat exchange with the part of described hexane streams is higher, can not satisfy when preamble is described to be required, the method for described gaseous stream being carried out heat exchange in heat transfer zone also comprises: will with described heat transferring medium heat exchange after logistics cooling.Can adopt this area the whole bag of tricks commonly used with described heat transferring medium heat exchange after the logistics cooling, as long as the stream temperature after the cooling satisfies previously described requirement (that is, T
2＞T
1, and T
2With T
1Between difference for greater than 0 and be not higher than 20 ℃, be preferably more than 0 and be not higher than 15 ℃, more preferably 5-15 ℃) get final product.Particularly, can with described heat transferring medium heat exchange after logistics and heat-eliminating medium carry out heat exchange, described heat-eliminating medium can be for this area various heat transferring mediums commonly used, such as recirculated cooling water.
Of the present invention a kind of preferred embodiment in, described heat transfer zone be provided with for the part of the described gaseous stream that contains water and hexane and described hexane streams is carried out the First Heat Exchanger of heat exchange and be used for will with a part of heat exchange of described hexane streams after the second interchanger of logistics cooling, contain the gaseous stream of water and hexane and the part of described hexane streams is carried out heat exchange in First Heat Exchanger with described, and the hexane streams after the heat exchange is sent in the drying zone as the heating medium that boils again.Carry out the temperature of the logistics that contains hexane and water after the heat exchange for satisfying previously described requirement (that is, T with the part of described hexane streams
2＞T
1, and T
2With T
1Between difference for greater than 0 and be not higher than 20 ℃, be preferably more than 0 and be not higher than 15 ℃, more preferably 5-15 ℃) time, directly this logistics is sent into and is carried out component distillation in the drying zone; The temperature of the logistics that contains hexane and water after carrying out heat exchange with the part of described hexane streams is higher, can not satisfy when preamble is described to be required, with the logistics that contains hexane and water after the heat exchange send in described the second interchanger carry out heat exchange with heat-eliminating medium (for example recirculated cooling water) after, send into and carry out component distillation in the drying zone.
Described First Heat Exchanger and the second interchanger can be this area various interchanger that can realize heat exchange function commonly used, for example: tube and shell heat exchanger.The present invention is not particularly limited for the operational conditions of described First Heat Exchanger and the second interchanger, can select for the routine of this area, and this paper no longer describes in detail.
The another part that comes from the hexane streams of described drying zone can be with the recirculated cooling water rear output of lowering the temperature.Be used for the angle of the heat that this part hexane streams of output carries from further raising, Recycling hexane method of the present invention also comprises: the gas phase mixture stream thing of the described hexane that will obtain at drying zone and water carries out condensation and oily water separation successively, obtain water logistics and oil phase logistics, and with exporting after the other part of described hexane streams and the described oil phase logistics heat exchange, the oil phase logistics after the heat exchange is sent into carried out component distillation in the described drying zone.Heat exchange is carried out in another part and the described oil phase logistics that will come from the hexane streams of described drying zone, can reduce on the one hand the temperature of this part hexane streams, makes it satisfy the requirement of output; Oil phase logistics after the heat exchange is because temperature raises (being generally 50-80 ℃) on the other hand, again sent into when carrying out component distillation in the described drying zone, can reduce will cross the logistics of cold oil phase and send into the thermal load that produces for drying zone in the drying zone.Oil phase logistics after the described heat exchange can be sent into by same opening for feed with logistics after the heat exchange that obtains in heat transfer zone and carry out component distillation in the drying zone, also logistics after the oil phase logistics after the described heat exchange and the heat exchange that obtains in heat transfer zone can be sent into respectively by different opening for feeds and be carried out component distillation in the drying zone.In the embodiment of the invention, with the oil phase logistics after the heat exchange and after the heat exchange that heat transfer zone obtains logistics send into by same opening for feed and carry out component distillation in the drying zone.
The method according to this invention, the amount of the hexane that the amount of the another part in the described hexane streams can be exported is as required carried out appropriate selection, is as the criterion so that the amount of the hexane of output can meet the demands.Usually, the weight ratio of the other part of described hexane streams and described hexane streams is 0.1-0.9:1.Preferably, the weight ratio of the other part of described hexane streams and described hexane streams is 0.15-0.25:1.
The method according to this invention is not particularly limited for the method for the gas phase mixture logistics of described hexane and water being carried out condensation, can select for the routine of this area.For example: can carry out heat exchange by gas phase mixture logistics and the cooling medium with described hexane and water, thereby with the gas phase mixture logistics condensation of described hexane and water, described cooling medium can be selected for the routine of this area, such as recirculated cooling water.Can adopt the whole bag of tricks commonly used (for example: standing separation or centrifugation) that described condensation product is divided into oil reservoir and water layer, and collect oil reservoir, thereby obtain the oil phase logistics.
The method according to this invention can be used in to be processed the various logistics that contain water, oligopolymer and hexane, thereby reclaims and the purifying hexane.Oligopolymer in the described logistics that contains water, oligopolymer and hexane is generally the oligopolymer that produces in the olefin polymerization process, and described oligopolymer is dispersed in the hexane, can it be separated with hexane with water by the method for evaporation.The method according to this invention is specially adapted to produce in polyolefine, the particularly poly production equipment as solvent with hexane, to reclaim and the purifying hexane.Particularly, the described logistics that contains water, oligopolymer and hexane can be for carrying out polymerization with hexane as solvent, and isolate the logistics that obtains behind the polymkeric substance, and for example from the mixture that slurry olefin polymerization obtains, isolate the logistics that obtains after the polyolefin products, described alkene is preferably ethene.
The described composition that contains the logistics of water, oligopolymer and hexane is not particularly limited, and can change with the difference in the source of this logistics.Particularly, come from when adopting slurry polymerization processes to prepare the production process of high density polyethylene(HDPE) in the described logistics that contains water, oligopolymer and hexane, take the total amount of the described logistics that contains water, oligopolymer and hexane as benchmark, the content of water can be the 0.025-0.04 % by weight, the content of oligopolymer can be the 1-5 % by weight, the content of hexane can be the 85-99 % by weight, and surplus is C
2-C
4Light constituent.
The method according to this invention, the specific form of described evaporating area can be selected for the routine of this area, as long as can realize the function of evaporating and can collect the gaseous stream that contains water and hexane that evaporation obtains.For example: described evaporating area is specifically as follows evaporator tower.
The method according to this invention, the operational conditions of described evaporating area is not particularly limited, can suitably select according to the composition of the described logistics that contains water, oligopolymer and hexane and the velocity of evaporation of expection, be as the criterion the hexane in the described logistics that contains water, oligopolymer and hexane and water can be steamed completely or almost completely.Taking into account under the condition of velocity of evaporation, angle from the energy expenditure of further reduction evaporating area, the condition of described evaporation so that, the temperature that obtains containing the gaseous stream of water and hexane from described evaporating area is 115-135 ℃, can guarantee further to reduce the energy expenditure of evaporating area under the condition that velocity of evaporation meets the demands like this.And, when the described temperature that contains the gaseous stream of water and hexane is within the above-mentioned scope, with this gaseous stream in heat transfer zone with carry out heat exchange as a part of hexane streams of heat transferring medium after, need not further cooling or only need a small amount of heat-eliminating medium to cool off to make the temperature of the logistics after the heat exchange to satisfy previously described requirement; In addition can also be so that the hexane streams after the heat exchange satisfies the requirement as the heating medium that boils again.
The method according to this invention, the composition of the gaseous stream that contains water and hexane that obtains from described evaporating area is decided with the composition of the logistics that contains water, oligopolymer and hexane of evaporating.Usually, come from when adopting slurry polymerization processes to prepare the production process of high density polyethylene(HDPE) in the described logistics that contains water, oligopolymer and hexane, take the total amount of the gaseous stream that contains water and hexane that obtains from described evaporating area as benchmark, the content of water can be the 0.025-0.04 % by weight, the content of hexane can be the 90-99 % by weight, and surplus is C
2-C
4Light constituent.
The method according to this invention, the component distillation condition in the described drying zone are not particularly limited and can select for the routine of this area.Usually, when the temperature of logistics was 80-130 ℃ after the heat exchange of sending into drying zone, preferably the pressure with drying zone was adjusted to 0.01-0.16MPaG, and the temperature of the hexane streams that obtains from drying zone like this is generally 80-130 ℃.After the described gaseous stream that contains water and hexane that a part and the temperature of hexane streams is 115-135 ℃ carries out heat exchange, hexane streams after the heat exchange generally can reach 85-132 ℃, be suitable for again being sent in the described dehydration tower as the heating medium that boils again, and carry out logistics after the heat exchange with the part of described hexane streams and only need a small amount of heat-eliminating medium even need not heat-eliminating medium to lower the temperature directly to send into and carry out component distillation in the drying zone; The temperature of simultaneously carrying out the oil phase logistics after the heat exchange with the hexane streams that is used for output then can reach 50-80 ℃, and it is sent into when carrying out component distillation in the drying zone, substantially can not improve the thermal load of drying zone.
The method according to this invention, described drying zone can be the common various forms of devices that can realize the component distillation purpose in this area, for example: described drying zone is specifically as follows dehydration tower.Can adopt this area the whole bag of tricks commonly used to regulate the pressure of drying zone, for example: when described drying zone is dehydration tower, can regulate by the tower top pressure of regulating dehydration tower the pressure of drying zone.
Fig. 2 shows a kind of preferred implementation according to Recycling hexane method of the present invention, describes the preferred implementation of the method according to this invention in detail below in conjunction with Fig. 2.
As shown in Figure 2, the logistics 8 that will contain water, oligopolymer and hexane is sent in the evaporator tower 1 and is evaporated, and obtains moisture and gaseous stream 10 hexane from the cat head of evaporator tower 1, and with 9 outputs of resistates at the bottom of the tower of evaporator tower 1.
The gas phase mixture logistics 13 that will obtain from the cat head of dehydration tower 7 hexane and water is sent into the hexane dehydration tower partial condenser 2 and is carried out condensation, to send into the knockout drum 4 from the logistics 18 of hexane dehydration tower partial condenser 2 outputs, not condensate 19 outputs, and condensation product left standstill in knockout drum 4, so that condensation product is divided into oil reservoir and water layer, to be exported by the water logistics 23 that water layer obtains, another part 16 that the oil phase logistics 20 that is obtained by oil reservoir is sent in the hexane liquid phase interchanger 5 with hexane streams 14 at the bottom of the tower that comes from dehydration tower 7 carries out heat exchange, the hexane streams 21 that temperature reduces is exported, the oil phase logistics 22 of temperature rising is sent into carried out component distillation in the dehydration tower 7.
The method according to this invention is applicable to the occasion of separation and purification hexane from the various mixtures that contain hexane, water and oligopolymer, the occasion of separation and purification hexane in the mixture that contains hexane, water and oligopolymer that is specially adapted to produce from polyolefinic production process particularly adopts slurry process to prepare the occasion of high density polyethylene(HDPE).
Below in conjunction with embodiment the present invention is described.
Embodiment 1-5 is used for illustrating Recycling hexane method of the present invention.
It is 200,000 ton/years production equipment that Recycling hexane method of the present invention is used for the HDPE industrial scale.
Adopt method shown in Figure 2, the logistics 8 that will contain water, oligopolymer and hexane is sent in the evaporator tower 1 with 70 tons/hour speed and is evaporated, and obtains containing the gaseous stream 10 of water and hexane from the cat head of evaporator tower 1.
The gaseous stream 10 that will contain water and hexane is sent in the hexane gas phase interchanger 6 and is carried out heat exchange with a part of logistics 15 of the hexane streams 14 of output at the bottom of the tower of dehydration tower 7, and the hexane streams 17 that temperature raises is sent in the dehydration tower 7 again as the heating medium that boils again.The logistics that contains water and hexane 11 that temperature is reduced is sent in the hexane dehydration column overhead condenser 3 and is carried out heat exchange with recirculated cooling water, and the logistics 12 after the heat exchange is sent into carry out component distillation in the dehydration tower 7.
The hexane that will obtain from the cat head of dehydration tower 7 and the gas phase mixture logistics 13 of water are sent into the hexane dehydration tower partial condenser 2 with behind the circulating cooling water condensation, send in the knockout drum 4, tell not condensate 19, and make condensation product be divided into oil reservoir and water layer, the water layer of lower floor is discharged as water logistics 23.The oil phase logistics 20 that obtains sent in the hexane liquid phase interchanger 5 carry out heat exchange with another part logistics 16 of the hexane streams 14 that obtains at the bottom of dehydration tower 7 towers, hexane streams 21 outputs that temperature is reduced, the oil phase logistics 22 that the temperature that obtains is raise is again sent into and is carried out component distillation in the dehydration tower 7.
Wherein, take the total amount of the described logistics 8 that contains water, oligopolymer and hexane as benchmark, the content of hexane is 97 % by weight, and the content of oligopolymer is 2.9 % by weight, and the content of water is 0.03 % by weight, and surplus is C
2-C
4Light constituent.
The total amount of the gaseous stream that contains water and hexane 10 that obtains take the cat head of evaporator tower 1 is as benchmark, and the content of hexane is 99 % by weight, and the content of water is 0.04 % by weight, and surplus is C
2-C
4Light constituent.
A part of logistics 15 of hexane streams 14 is 5:1 with the weight ratio of another part logistics 16 of hexane streams 14.
The tower top pressure of evaporator tower 1 is 0.25MPaG.The tower top pressure of dehydration tower 7 is 0.07MPaG, and the temperature out of cat head is 87 ℃.
The temperature that contains the gaseous stream 10 of water and hexane is 116 ℃, and the temperature of the logistics that contains water and hexane 11 that temperature reduces is 102 ℃, and the temperature of logistics 12 is 80 ℃ after the heat exchange; The temperature of a part of logistics 15 of hexane streams 14 is 91 ℃, and the temperature of the hexane streams 17 after the heat exchange is 93.5 ℃.The temperature of oil phase logistics 20 is 37.5 ℃, and the temperature of the oil phase logistics 22 that temperature raises is 71 ℃; The temperature of another part logistics 16 of hexane streams 14 is 91 ℃, and the temperature of the hexane streams 21 that temperature reduces is 59 ℃.
Comparative Examples 1
Adopt the logistics that the method identical with embodiment 1 will contain water, oligopolymer and hexane in evaporator tower, to evaporate, obtain containing the gaseous stream of water and hexane, this gaseous stream is carried out purifying according to method shown in Figure 1.
Particularly, the gaseous stream that will contain water and hexane is sent into after with the circulating cooling water condensation and is carried out oily water separation in the storage tank, the oil phase (temperature is 35 ℃) that obtains is sent in the dehydration tower and carried out component distillation (wherein, temperature and pressure in the dehydration tower is identical with embodiment 1), and after the part of the hexane streams that will export from dehydration tower and low-pressure steam are carried out heat exchange, send in the dehydration tower as the heating medium that boils again, another part of the hexane streams of exporting from dehydration tower is exported with the circulating cooling water cooling, wherein, the weight ratio that is used for as the hexane streams of the heating medium that boils again and the hexane streams that is used for output is 7:1.
Embodiment 2
Adopt the method recovery hexane identical with embodiment 1, different is:
The tower top pressure of evaporator tower 1 is 0.35MPaG.The tower top pressure of dehydration tower 7 is 0.13MPaG, and the temperature out of cat head is 102.5 ℃;
The temperature that contains the gaseous stream 10 of water and hexane is 121 ℃, and the temperature of the logistics that contains water and hexane 11 that temperature reduces is 112.5 ℃, and the temperature of logistics 12 is 87 ℃; The temperature of a part of logistics 15 of hexane streams 14 is 96 ℃, and the temperature of the hexane streams 17 that temperature raises is 99.5 ℃.The temperature of oil phase logistics 20 is 47.5 ℃, and the temperature of the oil phase logistics 22 that temperature raises is 79.5 ℃; The temperature of another part logistics 16 of hexane streams 14 is 96 ℃, and the temperature of the hexane streams 21 that temperature reduces is 64.5 ℃.
Embodiment 3
Adopt the method recovery hexane identical with embodiment 1, different is that the industrial scale of HDPE is 250,000 ton/years.
Comparative Examples 2
Adopt the method recovery hexane identical with Comparative Examples 1, different is that the industrial scale of HDPE is 250,000 ton/years.
Embodiment 3 is compared discovery with the low-pressure steam of Comparative Examples 2 consumption and the amount of recirculated cooling water: compare with the method for Comparative Examples 2, adopt the method for embodiment 3, the consumption of low-pressure steam has reduced 11.02 tons/hour, and the consumption of recirculated cooling water has reduced by 1398 tons/hour.
Adopt the method recovery hexane identical with embodiment 1, different is that the industrial scale of HDPE is 300,000 ton/years.
Comparative Examples 3
Adopt the method recovery hexane identical with Comparative Examples 1, different is that the industrial scale of HDPE is 300,000 ton/years.
Claims (13)
1. Recycling hexane method, the method comprises:
The logistics that will contain water, oligopolymer and hexane is evaporated in evaporating area, obtains containing the gaseous stream of water and hexane;
Described gaseous stream is carried out heat exchange in heat transfer zone, obtain logistics after the heat exchange that temperature reduces;
Component distillation is carried out in logistics after the described heat exchange in drying zone, obtain the gas phase mixture logistics of hexane streams and hexane and water;
Wherein, the temperature of logistics is T after the described heat exchange
1, this logistics forms the gas phase mixture logistics of described hexane and water in described drying zone temperature is T
2, the heat transfer boundary condition of described heat transfer zone so that: T
2＞T
1, and T
2With T
1Between difference for greater than 0 and be not higher than 20 ℃.
2. method according to claim 1, wherein, the method of described gaseous stream being carried out heat exchange in heat transfer zone comprises: the part of described hexane streams as heat transferring medium and described gaseous stream heat exchange, is sent in the described drying zone hexane streams that the temperature that obtains raises as the heating medium that boils again again.
3. method according to claim 2, wherein, the part of described hexane streams and the weight ratio of described hexane streams are 0.1-0.9:1.
4. method according to claim 2 wherein, also comprises described gaseous stream with method that heat transferring medium carries out heat exchange in heat transfer zone: will with described heat transferring medium heat exchange after the logistics cooling.
5. the described method of any one according to claim 1-4, wherein, T
2With T
1Between difference be 5-15 ℃.
6. the described method of any one according to claim 1-4, wherein, the evaporation conditions of described evaporating area is so that the described temperature that contains the gaseous stream of water and hexane is 115-135 ℃, the heat transfer boundary condition of described heat transfer zone so that after the described heat exchange temperature of logistics be 80-130 ℃.
7. method according to claim 1, wherein, the method also comprises: condensation and oily water separation are carried out in the gas phase mixture logistics of described hexane and water successively, obtain water logistics and oil phase logistics, and with exporting after the other part of described hexane streams and the described oil phase logistics heat exchange, the oil phase logistics after the heat exchange is sent into carried out component distillation in the described drying zone.
8. method according to claim 7, wherein, the other part of described hexane streams and the weight ratio of described hexane streams are 0.1-0.9:1.
9. according to claim 7 or 8 described methods, wherein, the temperature of the oil phase logistics after the described heat exchange is 50-80 ℃.
10. according to claim 1-4, the described method of any one in 7 and 8, wherein, the temperature of described hexane streams is 80-130 ℃.
11. method according to claim 1, wherein, the oligopolymer in the described logistics that contains water, oligopolymer and hexane is the oligopolymer of alkene.
12. method according to claim 11, wherein, the described logistics that contains water, oligopolymer and hexane is isolated logistics from the mixture that slurry olefin polymerization obtains.
13. according to claim 1-3, the described method of any one in 11 and 12, wherein, take the total amount of the gaseous stream that contains water and hexane that obtains as benchmark, the content of water is the 0.025-0.04 % by weight, and the content of hexane is the 90-99 % by weight, and surplus is C
2-C
4Light constituent.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210389932.0A CN103360194B (en) | 2012-03-28 | 2012-10-15 | A kind of Hexane recovery method |
| MYPI2012004750A MY169293A (en) | 2012-03-28 | 2012-10-25 | A method for recovering hexane |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210084778.6 | 2012-03-28 | ||
| CN201210084778 | 2012-03-28 | ||
| CN2012100847786 | 2012-03-28 | ||
| CN201210389932.0A CN103360194B (en) | 2012-03-28 | 2012-10-15 | A kind of Hexane recovery method |
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| Publication Number | Publication Date |
|---|---|
| CN103360194A true CN103360194A (en) | 2013-10-23 |
| CN103360194B CN103360194B (en) | 2015-10-21 |
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| CN201210389932.0A Active CN103360194B (en) | 2012-03-28 | 2012-10-15 | A kind of Hexane recovery method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109013126A (en) * | 2018-08-03 | 2018-12-18 | 诚亿电子（嘉兴）有限公司 | Diluent recovery unit and its recovery method |
| CN111925269A (en) * | 2020-07-30 | 2020-11-13 | 陕西延长石油延安能源化工有限责任公司 | Hexane refining system and method based on production of high-density polyethylene |
| KR20210037411A (en) * | 2019-09-27 | 2021-04-06 | 주식회사 엘지화학 | METHOD AND APPARATUS FOR PREPARING n-HEXANE |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109013126A (en) * | 2018-08-03 | 2018-12-18 | 诚亿电子（嘉兴）有限公司 | Diluent recovery unit and its recovery method |
| KR20210037411A (en) * | 2019-09-27 | 2021-04-06 | 주식회사 엘지화학 | METHOD AND APPARATUS FOR PREPARING n-HEXANE |
| KR102552143B1 (en) | 2019-09-27 | 2023-07-05 | 주식회사 엘지화학 | METHOD AND APPARATUS FOR PREPARING n-HEXANE |
| CN111925269A (en) * | 2020-07-30 | 2020-11-13 | 陕西延长石油延安能源化工有限责任公司 | Hexane refining system and method based on production of high-density polyethylene |
| CN111925269B (en) * | 2020-07-30 | 2023-06-27 | 陕西延长石油延安能源化工有限责任公司 | Hexane refining system and method based on production of high-density polyethylene |
Also Published As
| Publication number | Publication date |
|---|---|
| MY169293A (en) | 2019-03-21 |
| CN103360194B (en) | 2015-10-21 |
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