Random Packing - hatltd.com

1 Random 3 AlphaPACK DESIGN SHEETOVERVIEWP acked beds formed by dumping bulk Random Packing elements of consistentshape and size will provide the consistent surface and voidage characteristicsnecessary for predictable masstransfer operations. To achieve optimumperformance benefits from a packed bed, proper consideration of the design,specification and installation of the Random Packing and associated columninternals is OF Random PACKINGHAT manufactures a comprehensive range ofAlphaPACK standardand highperformance Random packings as listed Types:R+ Raschig Rings(Ceramics,Glass,Metals,Carbon,Plast ics)P+ Pall Rings(Ceramics, Metals, Plastics)S+, S++ Saddles(Ceramics, Plastics)High Performance Types:C+ Rings(Metals, Plastic)I+ Rings(Metals)L+, Q+, N+ Packings(Plastics) Random 3 AlphaPACK DESIGN SHEETThe above packings are available in several sizes as indicated on ourdesignsheetsto suit most commercial applications.

2 They range in size from 6mm to 90mm orequivalent. It is an essentially a design consideration in specifying a Packing sizebased on capacity and efficiency requirements. The nominal Packing size specifiedshould however not be greater than 1/10th of the column Packing is usually specified in the lowest cost material of manufacture that willsatisfy temperature and corrosion requirements. Some of the most commonmaterials listedin order of relative cost are:Polypropylene(mainly aqueous systems up to 100 deg. C)Carbonsteel(non-corrosive hydrocarbon systems)Ceramic(sulphuricacid &nitricacid absorbers)Stainlesssteels(most hydrocarbon systems)PVDF, PFA(corrosive aqueous systems up to 150 deg. C)PVC / C-PVC(corrosive aqueoussystems up to 90 deg. C)Other more exotic materials that may be specified includealuminium, Monel,titanium 3 AlphaPACK DESIGN SHEETPACKED BED DESIGNH ydraulic operation of packed beds can be accurately rated using correlations thathave been developed from actual performance data.

3 Design data forstandard"generic" Random Packing is widely available in the public "Generalised Pressure Drop Correlation" is the most frequently publisheddesign tool for calculating packed bed diameter and determiningthe operatingcapacity for most "generic" Random packings based upon a characteristic "PackingFactor" for each here reliable performance is required in high pressure hydrocarbon systems, morespecific design models should be are able to provide hydraulicrating sheets indicating the calculated pressure drop, liquid hold-up and %flood forany packed bed providing that sufficient process data is made aminimum, we would require a profile of internal vapour and liquid loads and actualdensities as well as liquid surface tension and have computer programs to predict mass transfer efficiency and calculate thepacked bed height for the most common absorption, stripping and heat transfersystems where sufficient, reliable data is available from which to compile distillation systems should be simulated to evaluate thenumber of theoretical trays required as well as providing tray by tray vapour andliquid loads and physical most cases we can predict suitable HETP'sand calculate packed bed height from this most "generic" type packingsin distillation service, separating efficiency will deteriorate when the bed heightexceeds the lower of 6 x columndiameter or 6 metre s due to the effects of data used to develop the design models used by HAT are in mostcases sourced from well engineered operating columns with associated internalsproperly designed to be compatiblewith the hashad wide application throughout the industry for a result.

4 Performance characteristics are well known and design datareadily accessible from public domain genericcolumnpackings canbe manufactured in a wide range of commercially available manufactured by HAT conforms to accepted industry standardsas listed below: Random 3 AlphaPACK DESIGN SHEETPACKINGTYPEMATERIALSIZEMASS(kg/m3)S URFACE(m2/m3)VOIDAGE%PACKINGFACTORR+Cera mic15mm82529062540 RaschigRing19mm8402606825525mm6501907216 038mm600135749550mm57092766575mm56079783 6R+Carbon12mm67936060450 RaschigRing18mm5902406626025mm6001956518 037mm5901406512550mm530986865P+Stainless 16mm5803409370 PallRingSteel25mm435207945038mm355128952 850mm270102962090mm230859716C+ + +Polypropylene16mm1153408797 PallRing25mm80196906438mm60150913650mm60 106912590mm90859217S+Ceramic19mm59033571 145 Saddle25mm580250779238mm600150805250mm56 0110794075mm540968022S+ +PolypropyleneNo. 2992238921 PackNo. 3671449214N+PolypropyleneNo. 2821809116 PackNo. 450131948Q+PolypropyleneNo. 43498967 PackNo.

5 73598967 Random 3 AlphaPACK DESIGN SHEETPACKED BED CAPACITYF looding in packed beds is characterised by unstable operation and loss ofefficiency. The optimum loading point for most new columns is about 80% of theloading at the flood point. Separation efficiency will usually deteriorate rapidly atloadings below about 20% of the flood point, particularly in distillation flood point for packed beds ofgenericpackings can be estimated using thefollowing correlation:-CFLOOD=1 /{ F . e(S. )}(m/s)and:% Flood=Csx100(at constantL/G)CFLOODx System Factorwhere:X= (L/G). ( G/ L) (dimensionless)Cs= vs. { G/ ( L G)} (m/s)L=Liquid Rate(kg/s)G=Gas Rate(kg/s) G=Gas Density(kg/m3) L=Liquid Density(kg/m3)vs=Superficial Gas Velocity(m/s)F= Packing Factor(from table)S= Packing Shape ConstantThe following Packing Shape Constants should be used for forceramicpackingsRandom 3 AlphaPACK DESIGN SHEETESTIMATION OF PRESSURE DROPTh e restriction to vapour flow across a packed bed causes a pressure drop which isnormally relatively the effect of pressure loss on overall plantdesign and operating costs will often need to be evaluated and so it is necessary tobe able to estimate this pressure loss over the expected range of drop is a function of vapour and liquid rates as well as the Packing shapeand size.

6 Pressure drop curves for most packings are widely published. Forestimating purposes it is usually more convenient to use a "Generalised PressureDrop Correlation" as shown below which applies a characteristic " Packing Factor" tothe ordinate value to provide a set of pressure drop curves which are accurate towithin 20% for PRESSURE DROP CORRELATION0. low P arameter - ( X )CAPACITYFACTOR=C .F. D ata AD ata BD ata CD ata DD ata ED ata FD ata GD ata HGE NERA L PRE SS URE-DRO P CHARTPr essur eDrop(Pa/m)10005003002001501007550 NOM ENC LATUR E:Capac ity Fac tor = Flow Parameter =L/Gx (dg/dl)0. 5C =Vsx (dg/(dl- dg))0. 5(m /s) = 0. 1x (1000/dl)0. 9Vs= Superf ic ial Gas Veloc ity(m /s)F = Packing Fac tor = Liquid V isc os ity(c p)L = Liquid Rate(k g/s)G = Gas Rate(k g/s)dg= Gas Dens ity(k g/m3)dl= Liquid Dens ity(k g/m3) Random 3 AlphaPACK DESIGN SHEETDELIVERY AND INSTALLATIONAn advantage ofrandomcolumnpacking is that being mass produced standardelements, delivery times are relatively short.

7 Since the same Packing can be used inmany applications irrespective of column size, HAT holds a substantial inventory ofmostAlphaPACK randomcolumnpackings for immediate shipment at is packaged and shipped by volumeadjustment factor must be applied to the calculatedcolumngeometric volume toestimate the shipping volume required to properly fill a packed bed to account foredgeand settlingeffects. The volume adjustment factor depends upon the packingshape and size and the bed allowance for installation losses, typically around 5%, should beadded to thesh ippingvolume calculated conformity with recommended installation procedure is necessary to ensureconsistent duplication of design techniques that result ininstallation crew walking on or raking the Packing must never be installation procedures can result in substantial Packing shortfall ( not sufficient for the required bed heightresulting in performancelosses).