The application requires the U.S. Provisional Patent Application No.60/411 of on September 17th, 2002 application, the rights and interests of 612 (" ' 612 applications ") according to 35U.S.C. § 119 (e).' 612 applications are incorporated herein for reference.
Embodiment
The inventive method and device are applicable to any loop reaction zone, and this reaction zone comprises the slurry of a kind of polymer solids in liquid medium, comprise the used slurry of olefin polymerization process.Especially, the inventive method and the device big volume loop reactor of fluid slurry of high solid concentration that can be applicable to circulate.
Term used herein " slurry " means solid and liquid is present in out of phase composition.Term " fluid slurry " means the slurry that in loop reaction zone round-robin comprises polymer solids and liquid medium.Solid can comprise catalyzer and olefin polymer such as polyethylene.Liquid medium can comprise a kind of inert diluent such as Trimethylmethane, and monomer, comonomer, molecular weight regulator such as hydrogen, static inhibitor, scale inhibitor, scavenging agent and other processing aid that is dissolved in wherein arranged.Perhaps, liquid medium can mainly be made up of unreacted monomer, for example in some propylene polymerization processes.Term " product slurry " means that part of slurry that is used to reclaim polyolefin products that takes out from loop reaction zone.
Design and build and a kind ofly have the ability to be provided for the required pressure head of big volume loop reactor of slurry polymerization and single pump of flow is very difficult, the especially situation when slurry solids is dense.Thrust of pump and flow are high more good more, because just can allow annular-pipe reactor to operate under higher solids concn like this.The solids concn height has many benefits.For example, the solids concn height means that usually the thinner of discharging as the part of product slurry still less in the reactor.In addition, high solid concentration can make the yield of the polymkeric substance of certain hour section improve (perhaps can prolong the residence time of polymkeric substance under the identical situation of productive rate, thereby improve the efficient of catalyzer).
Contrivers more of the present invention disclose a kind of method and apparatus at US 6,239 in 235 (being incorporated herein for reference), and high solid concentration pump wherein and continuous discharging accessory can significantly improve the solids concn in the reactor.By this method and apparatus, solids concn can surpass 40wt%.(in this application,, particularly use under the situation of chromic oxide/silicon oxide, so the weight of catalyzer is ignored because productive rate is very high.)
The inventive method and device are applicable to that the minimum solids concn of circulation is 45wt% or 46wt% or 47wt% or 48wt% or 49wt% or 50wt% or 51wt% or 52wt% or 53wt% or 54wt% or 55wt% or 56wt% or 57wt% or 58wt% or 59wt% or the fluid slurry of 60wt% at least at least at least at least at least at least at least at least at least at least at least at least at least at least at least at least.The inventive method and device are applicable to that also the high solid concentration that circulates is 75wt% at the most or 74wt%, 73wt%, 72wt%, 71wt%, 70wt%, 69% weight, 68wt%, 67wt%, 66wt%, 65wt%, 64wt%, 63wt%, 62wt%, the fluid slurry of 61wt% at the most at the most at the most at the most at the most at the most at the most at the most at the most at the most at the most at the most at the most at the most.Above-mentioned minimum concentration and maximum concentration can be absolute minimum concentration or maximum concentration, also can be the minimum or maximums of average solids concentration.The arbitrary Schwellenwert of solids concn as hereinbefore defined and arbitrary maximum can be made up the scope of delimiting solids concn, as long as selected Schwellenwert is lower than selected maximum.Under some situation, above-mentioned weight percent can be an approximation.
The inventive method and device are applicable to the homopolymerization of ethene and the copolymerization of ethene and senior 1-alkene such as butylene, 1-amylene, 1-hexene, 1-octene or 1-decene.A kind of preferred method be ethene with as the amount of starting raw material at 0.01-10wt%, preferred 0.01-5wt%, more preferably the comonomer of 0.1-4wt% scope carries out copolymerization, wherein comonomer is selected from above-mentioned senior 1-alkene, and weight percentage is based on the gross weight of ethene and comonomer.Perhaps, obtaining comonomer introducing amount with the comonomer of capacity as raw material is 0.01-10wt%, preferred 0.01-5wt%, the more preferably polyolefin products of the scope of 0.1-4wt%.This analog copolymer still is considered as polyethylene.
The thinner that is fit in the methods of the invention as liquid medium is known in this field, is included under the slurry polymerization conditions inertia and is liquid hydrocarbon.The hydrocarbon that is fit to comprises Trimethylmethane, propane, Skellysolve A, iso-pentane, neopentane and normal hexane, preferred especially Trimethylmethane.
In addition, to can be used for unreacted monomer be the situation that is used for the polymerization process liquid medium in the present invention.For example, present technique can be used for the polymerization of propylene, and wherein propylene is a liquid medium and do not have the inert diluent of any obvious amount.Thinner still can be used for catalyzer.For illustrating but not as restriction, will also can be used for the situation of monomer replacement thinner but should understand the present invention in conjunction with inert diluent polyethylene process prescription the present invention in the following description as liquid medium as liquid medium.
The catalyzer that is fit to also is well known in the art.Particularly suitable is the widely disclosed in the literature chromium oxide catalyst that is carried on carrier such as silicon oxide, and for example US 2,825, disclosed catalyzer in 721 (being incorporated herein for reference).This paper indication silica support is also contained any known silicon oxide-containing carrier, for example silica-alumina, silicon oxide-titanium oxide and silica-alumina-titanium oxide.Also can use any known other carrier such as aluminum phosphate.The present invention also is applicable to the polymerization process of using organo-metallic catalyst, and organo-metallic catalyst comprises that this area often is called those catalyzer of Z-type catalyst and metallocene catalyst.
About other details of loop reactor apparatus and polymerization process can be referring to for example US4,674,290,5,183,866,5,455,314,5,565,174,6,045,661,6,051,631,6,114,501 and 6,262,191,
All be incorporated herein for reference.
In annular-pipe reactor slurry polymerization process, use pump to come to provide round-robin prime mover as the fluid slurry that polymer solid particles is contained in the thinner.Can use impeller to place reactor or the interior pump of reaction zone.This propeller pump can make fluid slurry circulate with certain speed.Along with the increase of slurry velocity, the heat transfer of reactor between cooling jacket (or other cooling system) improves, and more high-load solid capable of circulation.But improving slurry velocity then needs the pump motor to provide the intensity of bigger power, higher pressure head and axle, bearing, sealing and impeller higher.Therefore preferably emphasize pump efficiency, structure detail and pump specification details.A lot of technology can be used to strengthen these aspects and help big volumetrical high solid concentration polymerisation slurry is carried out the high speed pumping
At first, can adopt pump arrangement, wherein the pump energy of rotation that is arranged to upstream pump is produced can be reclaimed by downstream pump to small part.For example, two pumps can be arranged on a horizontal segment or the minor segment.Two pumps can be placed on annular-pipe reactor adjacent pipe bent position so that first pump (upstream pump) can in opposite second pump (downstream pump) of wheel rotation direction, partly be recovered to the energy of rotation that slurry provides.So arrange and improved the pressure head and the flow of slurry, thereby improved the pumping efficiency of two pumpss in series.Fig. 3 and 4 illustrates this technology.In other situations, impeller needn't be arranged in the same pipeline section, if their close being enough to make the downstream impeller have benefited from the rotation of upstream impeller can.In other situations, by placing pump in the asymmetric arrangement mode and impeller can obtain tangible benefit.
The second, can utilize the guide vane (swirl vane or back swirl vane before being also referred to as) or the equipment of other driven rotation slurry to make slurry produce rotation herein.Swirl vane can make slurry produce rotation before arriving impeller before described.The opposite rotation of sense of rotation that is provided with impeller can be provided guide vane, thereby makes the relative rotation speed raising of described pump and make slurry that higher discharging speed and flow be arranged.This improves pump efficiency.Back swirl vane can make slurry flow produce rotation after impeller.According to desired effect, the rotation that back swirl vane produces can be identical with the sense of rotation that impeller is provided or opposite.Back swirl vane can be attached in the design of the pedestal that supports pump shaft or bearing seal outer cover.And if on an axle two or more homodromal impeller is arranged, then guide vane can place that making between the impeller rotatablely moves and is transformed into axial motion or reverse rotation is raised the efficiency, pump capacity and thrust of pump are poor.Fig. 5 illustrates the preceding swirl vane of implementing present technique or the guide vane laying method with respect to pump impeller.Swirl vane can make pump efficiency improve at least 2% or at least 3% or at least 4% or at least 5% or at least 6% or at least 7% or at least 8% or at least 9% or at least 10% before this.In some cases, above-mentioned value is an approximation.
The 3rd, the gap between the reactor tube of pump impeller and impeller outer cover is minimized.Between the reactor wall of impeller and impeller location, can define a gap.Make this gap minimize the recycle back that can reduce from pump discharge (high pressure) to pump intake (low pressure).So just can improve pumping capacity and pressure head.But the tendency that will make solid be broken into small-particle more or particulate like this increases, and must average out between the two.This gap can be 1/72 inch or littler, 1/64 inch or littler, 1/48 inch or littler, 1/32 inch or littler, 1/24 inch or littler, 1/16 inch or littler or 1/8 inch or littler.Above-mentioned gap width may be an approximation under some situation.
The 4th, can on a computer-controlled 6-axle milling machine, adopt Machining Technology to make the reactor pump impeller by aluminium, titanium or steel.Process with the metal block that sifts out sand holes in advance.Can prevent that like this thickness that can critically control the impeller cross section obtains required intensity, so that can bear desired high-head of the annular-pipe reactor of operating and flow under higher solids concentrations because of the impeller vulnerable area due to the sand holes.
The 5th, can adopt diameter greater than the pump impeller of annular-pipe reactor diameter (as the Fig. 2 of this paper and US 6,239,235 shown in Figure 8).For example, for the polyethylene loop reactor of 24 inches of diameters, can adopt diameter is 26 inches or bigger impeller.Perhaps, can adopt diameter is 28 inches or bigger impeller.Perhaps, can adopt diameter is 30 inches or bigger impeller.Also can use rotating speed (RPM) is 180~18,000 polyethylene loop reactor recycle pump, makes the annular-pipe reactor recycle pump reach 120~600 feet pumping head and 20,000~100,000GPM in the polyethylene loop reactor of diameter 24 inches (nominals).The annular-pipe reactor of other size then has other suitable scopes.
The 6th, can adopt radial pump or mixed.In radial pump or mixed, provide speed and the energy higher to slurry flow during impeller blade contact slurry than conventional propeller pump.Therefore, radial pump or mixed can produce higher flow head and speed, thereby have solved the pressure demand problem of big reactor better.This has become more as radial pump or typical impeller pump the axial flow pump characteristic, radially leaves impeller after wherein fluid stream enters pump vertically.In mixed, fluid stream has the vector of radial component to leave impeller again with existing axial component.The angle of this vector can be 0~90 degree, and wherein 0 kilsyth basalt shows that this vector leaves pump vertically, and 90 kilsyth basalts show that this vector radially leaves pump.
In new or improved annular tube type polyolefin production, above-mentioned technology arbitrary or all can with adopt continuous discharging, sedimentation leg, flash line heater, make thinner and the isolating flash system of polymkeric substance and make thinner directly loop back the polymerization process coupling of reactor by evaporation.Apparatus of the present invention and method can adopt continuous discharging with solids concn in the further raising reactor, as US 6,239, described in 235, are incorporated herein for reference.Perhaps or augment ground, apparatus of the present invention and method can improve settling efficiency with the sedimentation leg.Term " settling efficiency " is defined as the amount of polymers (lb/hr) of discharging from sedimentation leg (or continuously relief outlet) divided by adding isobutane diluent (lb/hr) total amount of discharge from sedimentation leg (or relief outlet) the continuously polymkeric substance (lb/hr) of discharging simultaneously.
Referring now to accompanying drawing,, Fig. 1 illustrates a classical ring pipe reactor 10 that vertical segment 12, upper horizontal segments 14 and lower horizontal segment 16 are arranged.These upper and lower horizontal segment 14 and 16 have defined the upper and lower district of horizontal flow.Place an impeller in the annular-pipe reactor 14 and make the slurry circulation.Each vertical segment 12 all links to each other with another vertical segment by corresponding horizontal segment 14.Vertical segment 12 can comprise heat exchange chuck (or claiming cooling jacket) 18.Vertical segment 12 and horizontal segment 14 constitute loop reaction zone.Loop reaction zone can comprise than more or less vertical segment 12 illustrated in fig. 1 and corresponding horizontal segment 14.And loop reaction zone can be vertical or horizontal direction.In addition, the some or all of horizontal segment that are connected with vertical segment 14 can be crooked.In fact, the connection pipeline section 14 that is used for connecting vertical segment 12 can be arbitrary shape or form and slurry can be flowed betwixt.
Make reactor cooling by the method that forms heat exchanger by vertical segment 12 and cooling jacket 18.As referred to above, the speed of slurry flow when pipeline section 12 is fast more, and then heat is just good more to the transmission of cooling jacket 18 from annular-pipe reactor 10, and the solids concn in the fluid slurry just can be high more like this.Each pipeline section all is connected with next pipeline section by a level and smooth joint or elbow 20, and a straightway substantially continuous stream is provided like this.Electric motor 24 drives impeller 22 (shown in Figure 2), impeller and then make slurry circulation.Monomer and add thinner and introduce by pipeline 26 and 28 respectively can directly be introduced reactor 10 by one or more position, perhaps merges with condensation diluent recycle line 30 as shown in the figure and introduces.Also can comonomer be introduced reactor by these pipelines.Can monomer and comonomer be introduced reactor 10 by arbitrary suitable technique, for example simply open described reactor, nozzle, spray thrower or other partitioning device.
Catalyzer is introduced equipment 32 by a catalyzer that can provide catalyzer to introduce district (position) and is introduced.Any being fit to, all can adopt to the method for annular-pipe reactor introducing catalyzer.For example, U.S. Patent No. 6,262,191 (incorporating the present invention into) as the reference file disclosed preparation catalyst slurry and the method and apparatus that is introduced into loop reaction (polymerization) district just can be used for method and apparatus of the present invention.
Reference numeral 34 is indicated roughly and is used for taking out continuously the vast sky heart annex of intermediate product slurry.Continuously discharging accessory 34 is positioned at or the downstream end of a contiguous bottom transverse pipeline section 16 and vicinity or just on connecting bend 20.Annular-pipe reactor can have one or more continuous discharging accessory.
In device shown in Figure 1, the product slurry enters hp flash drum 38 via conduit 36.Conduit 36 comprises a peripheral tube 40, supplies to have hot-fluid in the peripheral tube 40, indirectly the slurry heat supply in flash line 36.The thinner of vaporization distillates from flash tank 38 through conduit 42, and for further processing, comprise with reclaiming condenser 50 and carry out condensation through simple heat exchange, and needn't be compressed just by recycle diluent line 30 retrieval systems.Reclaim condenser 50 and can under any condition known in the art, use any suitable heat exchange fluid known in the art.But, normally used a kind of fluid (as steam) that is easy to provide certain temperature economically.The suitable temp scope of this heat exchange fluid is from 40~130 °F.
Polymer beads is discharged from hp flash drum 38 by pipeline 44, so that further handle with technology known in the art.Polymer beads can be delivered to low pressure flash chamber 46, reclaim by pipeline 48 as the polymkeric substance finished product afterwards.Can a surge tank (unreceipted on the figure) be installed between hp flash drum 38 and the low pressure flash chamber 46 so that keep pressure reduction between these two flash tanks.The distilled thinner enters pipeline 42 after via compressor 47.In the U.S. Patent No. 4,424,341 of people such as Hanson application, at length disclose this two step flash design, included its content in for referencial use.
Except the situation of 8 vertical segment shown in Figure 1 or " leg ", can adopt vertical segment 12 or " leg " of arbitrary number.Expect that one 12 leg reactor can benefit from technology disclosed in this invention.The length of flow of loop reaction zone is usually above 900 feet, perhaps surpass 1000 feet, perhaps surpass 1100 feet, perhaps above 1200 feet, perhaps above 1300 feet, perhaps surpass 1400 feet, perhaps surpass 1500 feet, perhaps above 1600 feet, perhaps above 1700 feet, perhaps surpass 1800 feet, perhaps surpass 1900 feet, perhaps above 2000 feet.Above-mentioned in some cases data are approximation.
The inventive method and device be because can effectively utilize pumping unit to produce superior performance, thereby be specially adapted to 30,000 gallons or bigger reactor, perhaps 33,000 gallons or bigger reactor, perhaps 35,000 gallon or bigger reactor, perhaps 36,000 gallons or bigger reactor, perhaps 40,000 gallon or bigger reactor, perhaps 42,000 gallons or bigger reactor, perhaps 44,000 gallon or bigger reactor, perhaps 46,000 gallons or bigger reactor, perhaps 48,000 gallon or bigger reactor, perhaps 50,000 gallons or bigger reactor, perhaps 60,000 gallon or bigger reactor, perhaps 70,000 gallons or bigger reactor, perhaps 80,000 gallon or bigger reactor, perhaps 90,000 gallons or bigger reactor, perhaps 100,000 gallons or bigger reactor.The volume number of front can be an approximation.Present technique can with two originally independently annular-pipe reactor well connect together.Really, as long as few relatively investment, just can utilize two same pumps that two 18,000 gal reactor are combined into one 36,000 gallons reactor, productive rate is then above 2 times.
The operating method of annular-pipe reactor 10 is to make the end that advances and go out of one or many pumps in 24 inches reactors of normal diameter produce the pressure reduction of 18psig at least, perhaps at least 20,22,24,26,28, the pressure reduction of 30psig.Usually the operating method of annular-pipe reactor 10 is the pressure heads (pressure-losses of expression per unit length reactor) that can produce at least 0.07 (reactor length of foot slurry pressure drop/24 inches reactors of foot normal diameter).With 2 feet of normal diameters (or 24 inches) is reference, means that then intermediate diameters is about 21.9 inches.For larger diameter, the per unit length reactor just needs higher slurry flow rate and bigger pressure drop.Here the density of supposing slurry is about 0.5~0.6 usually.
By adopting technology disclosed in this invention can obtain more High Pressure Difference or pressure head.For example, can improve pressure reduction by the speed of rotation of control pump impeller, the method that reduces the gap between impeller vane and the inside pipe wall or adopt more effective impeller to design.Also can improve pressure reduction or pressure head by the method for using at least one complementary pump.
Fig. 2 illustrates and is used for the continuous impeller 22 that moves in slurry longshore current road.Described impeller 22 has blade 74, and is installed on the axle 78 that links to each other with electric motor 24.Pipeline 21 has a vertical segment 12 and a lower horizontal segment 16, and 20 places are connected with each other at elbow.Electric motor 24 drive shafts 78, and then driven vane 74, impeller 22 promotes slurry and flows into elbow 20 along the arrow A direction like this, and then upwards flows into vertical segment 12.Can find out that from figure impeller 22 is arranged in the widened section 66 of pipeline 21, as promoting district 70.The diameter of pipeline 21 widened sections 66 is bigger than the diameter of pipeline 21 other parts.Only as an example, the diameter of pipeline 21 is 24 inches.Only as an example, the diameter of widened section 66 is greater than 24 inches.Therefore, impeller 22 diameters of surveying by blade 74 diameters are bigger than the diameter of pipeline 21.Only as an example, impeller 22 diameters of surveying by blade 74 diameters will be above 24 inches.Because widened section 66 allows to adopt bigger impeller in pipeline 21, then impeller 22 can promote slurry flow through pipeline 21 with higher speed.Big impeller 22 equally also can improve pressure head at the pressure of discharge port by increasing slurry.Only as an example, for 24 inches reactors of a diameter, big impeller 22 can produce the flow of 20,000~100,000 gallon of per minute of slurry and 120~600 feet pressure head.Therefore, big impeller 22 can also produce more at cooling jacket 18 (Fig. 1) and conduct heat, and makes the solids concn of annular-pipe reactor 10 (Fig. 1) institute output higher.
Perhaps, not with the method that strengthens impeller 22 diameters, but in the annular-pipe reactor of diameter 24 inches (standards), with than small impeller 22 with 180~18, the rotating speed of 000RPM is operated the pressure head and 20,000~50 that produces 120~240 feet, the flow of 000GPM.
Fig. 3 illustrates two pumps 100 and 102, and two pumps is to being placed on the two ends of pipeline 21 lower horizontal segment 16.For ease of clear, other device shown in Fig. 1 has been omitted, but will use these devices in the paradigmatic system of an operation.As shown in the figure, pump 100 and 102 makes slurry pass through annular-pipe reactor 10 along the arrow A direction.
Fig. 4 illustrates in greater detail two pumps 100 and 102 and pipeline 21.Pump 100 comprises the impeller 22a that has blade 74a, and is installed on the axle 78a that links to each other with electric motor 24a.Pump 102 comprises the impeller 22b that has blade 74b, and is installed on the axle 78b that links to each other with electric motor 24b.Pipeline 21 has two parallel vertical segment 12a and 12b and a lower horizontal segment 16, respectively vertical segment 12a and 12b is connected with each other at 20a and 20b elbow.Electric motor rotates 24a axle 78a, thereby the blade 74a on the impeller 22a is rotated with first sense of rotation.Electric motor 24b rotation axis 78b, thus the blade 74b on the impeller 22b is rotated with the second opposite sense of rotation.Only as an example, impeller 22a is rotated in a clockwise direction, and impeller 24b rotates in the counterclockwise direction.Slurry passes through pipeline 21 through pump 102 and then through pump 100 earlier along the arrow A direction.
Slurry head on flows into impeller 22b with the direction of parallel shafts 78b usually.When slurry flow was crossed the blade 74b of impeller 22b, blade 74b discharged slurry along the tangential angle of axle 78b and towards pipeline 21 inwall directions.Slurry with what angle where to discharge the sense of rotation that depends on impeller 22b from blade.The position of impeller 22a and impeller 22b will be near being enough to make slurry still to flow with this tangential angle near impeller 22a the time.Slurry engages the blade 74a of impeller 22a, because the sense of rotation of the sense of rotation of impeller 22a and impeller 22b is opposite, blade 74a turns to slurry, and slurry is discharged from impeller 22b, moves ahead along arrow A with parallel with axle 78a substantially direction.Like this, impeller 22a " has managed " route that flows to of slurry straight, and slurry is discharged with parallel with axle 78a substantially axis direction, and slurry flow is followed along vertical segment 12a to the upper reaches to elbow 20a then.In addition, because slurry is with certain angle engagement blade 74a, so can be to slip over drift angle blade 74a than slight drag.
Because normally the axial array mode with parallel shafts 78a is mobile when being discharged by impeller 22a for slurry, so the movement velocity of slurry after by pump 100 is only faster from the speed that pump 102 flows through than it.From pump 102 effusive motion of slurry speed is that inside pipe wall can make it turn to and make flow velocity to reduce like this because slurry can be along the flows at angles towards pipeline 21 inwalls more slowly.In addition, because slurry to be slipping over blade 74a than slight drag, it is littler that impeller 22 promotes the required power of slurry.Therefore, two backward rotation pumps 100 that the position is close and 102 series connection are put, the kinetic energy that offers slurry by pump 102 just can part by pump 100 recovery, make slurry more effectively flow through pipeline 21 and leave pump 100 with more speed.Like this, two pumps 100 and 102 just can reach the effect that improves solids concn.
Available two sections pump substitutes two pumps that separate 100 and 102.Two sections pumps comprise and are sequentially arranged in two opposite impellers of sense of rotation in the same pump.
Fig. 5 illustrates the guide vane 114 in pump 100 and the pipeline 21.When slurry when direction of arrow A flows through pipeline 21, guide vane 114 is positioned at the upstream of pump 100.Like this, these guide vanes are exactly preceding swirl vane.Guide vane 114 extends to pump 100 from the inwall of pipeline 21.Guide vane 114 is all crooked from inwall radial inflow ground with same angle.Slurry roughly is that parallel shafts 78 craspedodromes arrive guide vane 114 along the arrow A direction.When slurry engaged with guide vane 114, guide vane 114 offered the rotation or the eddy flow of slurry certain angle, made slurry and the axle 78 angled inwalls that flow to pipeline 21.Guide vane 114 makes slurry still rotation counterclockwise clockwise, depend on the direction of guide vane 114 from pipeline 21 inwall bendings.Only as an example, the direction of guide vane 114 is that slurry is rotated counterclockwise.
Slurry leaves guide vane 114, with the axle 78 angled mobile impellers 22 that contact.The sense of rotation of preferred impeller 22 is opposite with the slurry sense of rotation that guide vane 114 is caused.The sense of rotation of impeller can be identical with the slurry sense of rotation that guide vane is caused.Only as an example, impeller 22 clockwise directions rotation.Because slurry engages with certain angle and blade 74 and be opposite with the sense of rotation of blade 74, slurry slips over drift angle blade 74, and its resistance reduces when the blade 74 than the direct counterflow of slurry.Like this, the less impedance that is subjected to blade 74 of the slurry velocity when flowing through impeller 22, and the speed of rotation of impeller 22 is less by the slurry impedance.Therefore, when slurry leaves impeller 22, only need less power to improve the speed of slurry, impeller 22 obtains joint and promotes the required power of slurry still less from electric motor 24.
In addition, when the sense of rotation slurry of impeller 22 with flow through guide vane 114 after sense of rotation when opposite, blade 74 can make slurry turn to, and slurry is discharged from impeller 22, moves ahead along the direction of arrow A with substantially parallel axle 78.Like this, impeller 22 " has been managed " route that flows to of slurry straight, and slurry is discharged with parallel with axle 78a substantially axis direction.When slurry is discharged with the direction of parallel shafts 78, its velocity of flow than slurry certain angle being arranged to fast when pipeline 21 inwall directions are discharged with axle 78 because inwall hinders and deflection slurry mobile.
Fig. 6 provides another view of guide vane 110, and among this figure, shown guide vane 110 exposes from the pipeline 21 that is not connected with the reactor rest part.
Therefore, use guide vane and pump 100, leave the speed of pump 100 by the raising slurry, and reduce rotary blade 22 required drives, improved the efficient that slurry moves past annular-pipe reactor 10 (Fig. 1).Like this, use guide vane and impeller 22 that slurry solids concentration is improved.
In the used traditional axial flow pump of reactor, the gradient of its impeller vane or the angular range of saying relative axle are limited.Therefore, the slurry of discharging from axial flow pump blade inner is mainly along moving with the direction of the axle almost parallel of impeller.But because blade limits gradient, so blade has hindered flowing of slurry, flow velocity can reduce when slurry engaged with blade.Like this, propeller pump just needs sizable energy to improve the flow velocity of slurry.
Fig. 7 illustrates the mixed 200 that is arranged in pipeline 21.Pump 200 is installed in the pipeline 21 in the arch pump case 204 of a diameter greater than pipeline 21.Pump 200 has an impeller 228, receive one extend pipeline 21 the axle 212 on.Impeller 228 has the blade 208 that has a certain degree and place with axle 212.The direction of blade 208 is 0~90 degree with the angle of axle 212.Pump 200 comprises a bossing 216, near the axle 212 of position in pump case 204, defines a bending or arc runner 220 between the inwall 224 of bossing 216 and pump case 204.
In mixed as shown in Figure 7, slurry flow is crossed pipeline 21 and is flowed to pump 200 and engage with blade 208 along arrow B.Because blade 208 is arranged (angle of axle 212 relatively) with different gradients, when impeller 228 rotated, slurry was crossed blade 208 with less drag stream, and only needs less energy to improve the velocity of flow of slurry.Therefore, mixed can more effectively improve the velocity of flow of slurry than propeller pump.Slurry is all very big with axle 212 vertical velocity components with parallel both direction when leaving blade 208.The velocity component of slurry all captures in passage 220, and the arcuate inner walls 224 of runner changed the direction of slurry velocity component gradually, and making slurry is that direction with parallel shafts 212 flows to pipeline 21 when leaving pump case 204.Therefore, mixed can produce higher pressure head and slurry flow rate than traditional axial flow pump, effectively changes the flow direction of slurry afterwards when it leaves impeller 228, and the flow velocity of raising and pressure head can not lost.Like this, mixed has just effectively produced and has satisfied big reactor pressure and require necessary flow head and speed.
Be to be noted that propeller pump also can be used in the structure of Fig. 7.The operation of propeller pump is similar with mixed, and the lot of advantages of mixed also can be provided, and still, propeller pump is mostly to be with the direction of Z-axis 212 slurry to be discharged from impeller vane.
In addition, but also longshore current road 220 eddy flow direction and the flow velocity that back eddy flow guide vanes change slurry is installed.The slurry eddy flow direction of discharging from impeller 228 is identical with the sense of rotation of impeller 228 usually, and slurry just is not direct outlet towards runner 220 like this.Back eddy flow guide vane changes and has turned to speed, the energy of slurry and flows, and the slurry that guide vane is discharged is mostly to be that direction with parallel shafts 212 moves ahead.Like this, back eddy flow guide vane has improved slurry flows pressure head and pump efficiency.These guide vanes are our known decollator, stator or pole also.They also can provide the effect of mechanical support in runner 200.
Mixed or propeller pump can with the others coupling that is used for the annular-pipe reactor technology disclosed in this invention, comprising: the minimum clearance between the layout of double pump, guide vane, impeller vane and the pipe, production technology, diameter are greater than the impeller of pipeline diameter.
Return Fig. 2, the inwall that the blade 74 blade tip places 88 of impeller 22 arrive near widened section 66, but in fact do not contact inwall.Distance between blade tip 88 and the inwall has certain interval.In the operating process, the blade tip 88 that some slurry that flow to impeller 22 downstreams can be crossed blade 74 again turns back to impeller 22 upstream ends, and like this, impeller 22 is had to engage once more it usually and engaged once slurry.The repeated treatments slurry needs impeller 22 that more power is arranged and the pumping process that can slow down.Therefore, the round-robin slurry can cause along with annular-pipe reactor reduces decrease in efficiency because of slurry flow rate repeatedly.
The two gap is more little, and the possibility that the blade tip 88 that the slurry that has flow to impeller 22 downstreams is crossed blade turns back to impeller 22 upstream ends is just more little.Preferred gap is 1/64 inch or littler among Fig. 2.Blade tip 88 by making blade 74 and the gap of pipeline 21 inwalls reach 1/64 inch or littler method makes impeller 22 reduce recirculation, has improved speed and pressure when slurry is discharged, thus the flow and the pressure head that improve.The improvement that slurry is crossed pressure head, speed and the flow aspect of impeller 22 can make that solids concn is improved in the product slurry.
Last point, the impeller made from aluminium, titanium or steel 22 is more durable, and the life-span is longer.For example circulating, the used industrial pump routine of reactant is to be detected by production firm in the closed circuit reactor, and should detect necessary pressure to avoid sand holes.Processing impeller 22 on computer-controlled 6-axle milling machine, this milling machine can threaten the metal block of the casting sand hole of impeller 22 structural integrities to be processed into impeller 22 by sifting out.In addition, computer-controlled 6-axle milling machine can be used to accurately control the thickness of impeller 22, and guarantee that impeller 22 bears the necessary bulk strength of fair speed, pressure and traffic requirement, therefore improved the production efficiency and the solids yield of annular-pipe reactor 10 (Fig. 1).
The pressure head, flow velocity and the flow that use above-mentioned technology to improve slurry are improved the solids concn of being produced.Slurry will make slurry more to the heat transfer of cooling jacket in the raising of annular-pipe reactor velocity of flow.The raising of conducting heat will make polymerization process more effective and in producing the slurry process higher solid yield is arranged.
Although describe the present invention with reference to some concrete schemes, it will be understood by those skilled in the art that and to make many changes without departing from the scope of the invention or replace to some equivalence.In addition, without departing from the scope of the invention, be applicable to content of the present invention, can make many improvement for making some Special Circumstances or material.Therefore in fact the present invention is not limited to disclosed specific embodiment, and the present invention will comprise that all belong to the scheme in the claims scope.