The factors causing the fluctuation of the spheroidization process of ceramsite sand and the design points

Categories:Technical service
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Time of issue:2012-12-10
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(Summary description)Spheroidizationprocessofceramsitesand.Intheprocess,thefreshwetceramsitesandandthecirculatingsieveresiduearemixedevenlyandusedasthefeedforthedrum.Atthefeedendofrotarydrum,therearetwowaystoincreasetheparticlesizeoffreshfeed,oneisthatthefreshpowdercladdingisontheexistingrecycledgranule,theotheristogeneratenewagglomerates.Iftheoperationisstable,mustmakethestabilityofthemassofthenewnucleargenerationrateandgrainsizemeettherequirementsofmassproductionratesareequal,infactit'sdifficulttoachievethebalanceofaccurate,becauseevenifthewetcontentintherawmaterialintheprocessofnodulizingandrawmaterialinputflowrateremainsthesame,intheprocessofmaterialcirculationwillalsochange(pulse).Intypicalindustrialoperations,thecycletimeisbetween8and12minutes,thematerialcyclevolumeis150%to300%ofthefeedflow,andthefluctuationrangeis20%oftheaverage. Becausetherotarycylinderdoesnothavethesameautomaticscreeningfunctionastheswashplate,thesizedistributionrangeofmaterialdischargedfromthecylinderisverywide.Therefore,thecirculardrumsuwawithaclosed-circuitwaytosiftleftovermaterialbacktothedrumentrance(ofcourse,ifthereisasieveonthethingshouldbebroken).Inaddition,aswiththeoriginalceramsitespheroidization,ifthedesiredparticlesizeisincreasedinonepass,thelengthoftherotarycylindermustbelarge.Therefore,itisnecessarytocirculatethematerialthroughtherotatingcylinderseveraltimes.Ifcyclicoperationisadopted,largespaceisrequiredandthesameauxiliarymachinesastheslantingplategranulatorarecommonlyused.Inaddition,controlproblemsexistinthespheroidizationprocessitself. CarterandWrightdescribethefluctuationsinthespheroidizationprocessofceramsitesand.Ifthereistoomuchfluctuationinoperation,itisprobablycausedbylowmoisturecontent.Thepelletizationratebegantodecreaseduetooperationalfluctuations,thematerialcirculationvolumeincreased,andthelumpcoregrowthratewasfurtherhinderedbecausemostofthefreshrawmaterialswereusedforthegranularitycoarseningoftherecycledmaterials.Duetothedecreaseofnucleargrowthrate,thespheroidizationprocesstendstobeinterrupted,thatis,thecoarseningofcircularballsizeactuallypreventstheformationofagglomeratesuntilthecircularballsizeislargeenoughtoberequired.Whenmostofthesystemmeetsthegranularityrequirementsandisspheroidized,thecorereforms.Thewholeprocessstartsalloveragain. Thus,theincreasednucleargrowthratecanobviouslyimprovethestabilityofsystemblowing.Thefillingofwaterbysprayintherotatingcylindercanreducetheamountofmaterialcirculationandreducethefluctuationoftheprocess.However,theformedlumpsmayhavelowstrengthandirregularshape,sowhenthematerialcirculationisrelativelylarge,fluctuationshouldbeavoidedandtheoperationshouldbestable,otherwisetheproductqualitymayhaveproblems.Therearemanywaystomaintainstability,themostimportantistofollowtheoperationalrequirementsofcarefuldesign.Becauseofthemoisturecontentofrawmaterials,inputrate,rotatingspeedandchangesintheinnersurfaceoftherotatingcylinderwillaffectthestabilityofoperation,sothedesignshouldbecareful. Theuseofmulti-systemcirculatoryequipmenthelpstomitigateoperationalfluctuations.Themaximumfluctuationsgeneratedbyonesystemcanbecompensatedforbytheminimumfluctuationsgeneratedbyanothersystem.Inordertomaintainstableoperation,adouble-rotatingbarrelprocesscanalsobeadoptedtoproperlycontroloperatingconditions.First,proportionalcoresaregeneratedinthefirstrotatingbarreltoformlumps,andthenmorerawmaterialsaretransferredtothesecondrotatingbarrel,inwhichseedsarecoarse-grainedintoqualifiedproductsbycladdingmethod.

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The factors causing the fluctuation of the spheroidization process of ceramsite sand and the design points

(Summary description)Spheroidizationprocessofceramsitesand.Intheprocess,thefreshwetceramsitesandandthecirculatingsieveresiduearemixedevenlyandusedasthefeedforthedrum.Atthefeedendofrotarydrum,therearetwowaystoincreasetheparticlesizeoffreshfeed,oneisthatthefreshpowdercladdingisontheexistingrecycledgranule,theotheristogeneratenewagglomerates.Iftheoperationisstable,mustmakethestabilityofthemassofthenewnucleargenerationrateandgrainsizemeettherequirementsofmassproductionratesareequal,infactit'sdifficulttoachievethebalanceofaccurate,becauseevenifthewetcontentintherawmaterialintheprocessofnodulizingandrawmaterialinputflowrateremainsthesame,intheprocessofmaterialcirculationwillalsochange(pulse).Intypicalindustrialoperations,thecycletimeisbetween8and12minutes,thematerialcyclevolumeis150%to300%ofthefeedflow,andthefluctuationrangeis20%oftheaverage. Becausetherotarycylinderdoesnothavethesameautomaticscreeningfunctionastheswashplate,thesizedistributionrangeofmaterialdischargedfromthecylinderisverywide.Therefore,thecirculardrumsuwawithaclosed-circuitwaytosiftleftovermaterialbacktothedrumentrance(ofcourse,ifthereisasieveonthethingshouldbebroken).Inaddition,aswiththeoriginalceramsitespheroidization,ifthedesiredparticlesizeisincreasedinonepass,thelengthoftherotarycylindermustbelarge.Therefore,itisnecessarytocirculatethematerialthroughtherotatingcylinderseveraltimes.Ifcyclicoperationisadopted,largespaceisrequiredandthesameauxiliarymachinesastheslantingplategranulatorarecommonlyused.Inaddition,controlproblemsexistinthespheroidizationprocessitself. CarterandWrightdescribethefluctuationsinthespheroidizationprocessofceramsitesand.Ifthereistoomuchfluctuationinoperation,itisprobablycausedbylowmoisturecontent.Thepelletizationratebegantodecreaseduetooperationalfluctuations,thematerialcirculationvolumeincreased,andthelumpcoregrowthratewasfurtherhinderedbecausemostofthefreshrawmaterialswereusedforthegranularitycoarseningoftherecycledmaterials.Duetothedecreaseofnucleargrowthrate,thespheroidizationprocesstendstobeinterrupted,thatis,thecoarseningofcircularballsizeactuallypreventstheformationofagglomeratesuntilthecircularballsizeislargeenoughtoberequired.Whenmostofthesystemmeetsthegranularityrequirementsandisspheroidized,thecorereforms.Thewholeprocessstartsalloveragain. Thus,theincreasednucleargrowthratecanobviouslyimprovethestabilityofsystemblowing.Thefillingofwaterbysprayintherotatingcylindercanreducetheamountofmaterialcirculationandreducethefluctuationoftheprocess.However,theformedlumpsmayhavelowstrengthandirregularshape,sowhenthematerialcirculationisrelativelylarge,fluctuationshouldbeavoidedandtheoperationshouldbestable,otherwisetheproductqualitymayhaveproblems.Therearemanywaystomaintainstability,themostimportantistofollowtheoperationalrequirementsofcarefuldesign.Becauseofthemoisturecontentofrawmaterials,inputrate,rotatingspeedandchangesintheinnersurfaceoftherotatingcylinderwillaffectthestabilityofoperation,sothedesignshouldbecareful. Theuseofmulti-systemcirculatoryequipmenthelpstomitigateoperationalfluctuations.Themaximumfluctuationsgeneratedbyonesystemcanbecompensatedforbytheminimumfluctuationsgeneratedbyanothersystem.Inordertomaintainstableoperation,adouble-rotatingbarrelprocesscanalsobeadoptedtoproperlycontroloperatingconditions.First,proportionalcoresaregeneratedinthefirstrotatingbarreltoformlumps,andthenmorerawmaterialsaretransferredtothesecondrotatingbarrel,inwhichseedsarecoarse-grainedintoqualifiedproductsbycladdingmethod.

Categories:Technical service
Author:
Origin:
Time of issue:2012-12-10
Views:0

Spheroidization process of ceramsite sand. In the process, the fresh wet ceramsite sand and the circulating sieve residue are mixed evenly and used as the feed for the drum. At the feed end of rotary drum, there are two ways to increase the particle size of fresh feed, one is that the fresh powder cladding is on the existing recycled granule, the other is to generate new agglomerates. If the operation is stable, must make the stability of the mass of the new nuclear generation rate and grain size meet the requirements of mass production rates are equal, in fact it's difficult to achieve the balance of accurate, because even if the wet content in the raw material in the process of nodulizing and raw material input flow rate remains the same, in the process of material circulation will also change (pulse). In typical industrial operations, the cycle time is between 8 and 12 minutes, the material cycle volume is 150% to 300% of the feed flow, and the fluctuation range is 20% of the average.

Because the rotary cylinder does not have the same automatic screening function as the swash plate, the size distribution range of material discharged from the cylinder is very wide. Therefore, the circular drum suwa with a closed-circuit way to sift leftover material back to the drum entrance (of course, if there is a sieve on the thing should be broken). In addition, as with the original ceramsite spheroidization, if the desired particle size is increased in one pass, the length of the rotary cylinder must be large. Therefore, it is necessary to circulate the material through the rotating cylinder several times. If cyclic operation is adopted, large space is required and the same auxiliary machines as the slanting plate granulator are commonly used. In addition, control problems exist in the spheroidization process itself.

Carter and Wright describe the fluctuations in the spheroidization process of ceramsite sand. If there is too much fluctuation in operation, it is probably caused by low moisture content. The pelletization rate began to decrease due to operational fluctuations, the material circulation volume increased, and the lump core growth rate was further hindered because most of the fresh raw materials were used for the granularity coarsening of the recycled materials. Due to the decrease of nuclear growth rate, the spheroidization process tends to be interrupted, that is, the coarsening of circular ball size actually prevents the formation of agglomerates until the circular ball size is large enough to be required. When most of the system meets the granularity requirements and is spheroidized, the core reforms. The whole process starts all over again.

Thus, the increased nuclear growth rate can obviously improve the stability of system blowing. The filling of water by spray in the rotating cylinder can reduce the amount of material circulation and reduce the fluctuation of the process. However, the formed lumps may have low strength and irregular shape, so when the material circulation is relatively large, fluctuation should be avoided and the operation should be stable, otherwise the product quality may have problems. There are many ways to maintain stability, the most important is to follow the operational requirements of careful design. Because of the moisture content of raw materials, input rate, rotating speed and changes in the inner surface of the rotating cylinder will affect the stability of operation, so the design should be careful.

The use of multi-system circulatory equipment helps to mitigate operational fluctuations. The maximum fluctuations generated by one system can be compensated for by the minimum fluctuations generated by another system. In order to maintain stable operation, a double-rotating barrel process can also be adopted to properly control operating conditions. First, proportional cores are generated in the first rotating barrel to form lumps, and then more raw materials are transferred to the second rotating barrel, in which seeds are coarse-grained into qualified products by cladding method.

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