RALU-RING - Raschig

RALU-RINGSubjectpage RALU RING 1-3 Materials 4-5 Compensation for the "decrease in volume"for dumped packings 6 Generally applicable pressure drop diagramfor tower packings 7 Tower packing factor 8-9 Pressure drop with metal RALU RINGS 10-11 Pressure drop with plastic RALU RINGS 12-13 Absorption of CO 2 into NaOH 14-16for plastic Ralu-Rings Desorption of oxygen from water 17-19for plastic Ralu-Rings Height of a transfer unit HTU OV 20for plastic Ralu-Rings Comparison graph RALU RING / PALL Ring 21for plastic Ralu-RingsThe data in this brochure is based on numeroustests and careful studies.However, it can and is only intended to providenon-binding advice.No guarantee claims can be derived from this information.

RALU RINGSmade of plasticPolypropylene and polyethylene of different gradesNominalSizesWeightkg/m 3Numberper m 3Surfacem 2 /m 3Free Volume%5/8" - 15 80 170 000 320 941" - 25 56 36 000 190 941 ½ " - 38 65 13 500 150 952" - 50 55 5 780 110 953 ½ " - 90 40 1 000 75 905" - 125 30 800 60 97Multiplication factors to determine the weights for the high-performancethermoplastics listed below:Polyethersulfone (PES) 1,85Polyphenylene sulfide (PPS) 1,80Liquid crystal polymer (LCP) 1,83Polyvinylidene fluoride (PVDF) 2,0fluor. Ethylenpropylene (FEP) 2,40Perfluoralkoxypolymer (PFA) 2,40Ethylen-Chlortrifluorethylen (E-CTFE) 1,97Ethylen-Tetrafluorethylen (E-TFE) 2,20Polyarylether Ketone (PAEK) 1,44Fluoroplastics (Teflon) 2,15 - 2,4Polypropylene 30 %fiberglass-reinforced 1,25Polyethylene 1,102

RALU-RINGMaterialsmost often used for manufacturing RALU RINGS.Metalsmainly carbon steel and chromium-nickel steels but also specialalloys such as brass, Hastelloy, Monel, Incoloy, as well asaluminium, nickel, copper, etc.Plasticsmainly thermoplastics, such as polypropylene, polyethylene invarious grades.High-performance thermoplastics, such as polyethylene sulfide,polyvinylidene fluoride, polyether sulfone and liquid crystal polymersare being used in even increasing range of applications.As a rule, we always use virgin materials. Regenerated material areonly used upon special request.Our standard range comprises the following polypropylene:polypropylene standard (PP)for operating temperatures of up to approx. 70 °C (158 °F).heat-endurance stabilised polypropylene (LTHA)for operating temperatures of up to approx. 110 °C (230 °F).30 % fibreglass-reinforced polypropylene (GFR)for operating temperatures of up to approx. 135 °C (275 °F).Furthermore, it is also possible to offer various additive masterbatches. Thus, for example, for special applications, the specifygravity of the polypropylene tower packings can be raised to above1.4

RALU-RINGThe following high-performance thermoplastics are used:Polyether sulfone (PES)operating temperature range up to approx. 180 °C (356 °F).cold resistance down to approx. -100 °C (-148 °F).Polyphenylene sulfide (PPS)operating temperature range up to approx. 220 °C (428 °F),temporarily permissible up to 260 °C (500 °F),cold resistance down to approx. -50 °C (-58 °F).Liquid crystal polymer (LCP)operating temperature range, depending on type, up to a maximumof 240 °C (464 °F).Polyvinylidene fluoride (PVDF)operating temperature range up to approx. 140 °C (284 °F),cold resistance down to approx. -40 °C (-40 °F).Fluoroplastics (TEFLON, e.g. FEP, PFA)(Teflon in various material grades)operating temperature range, depending on type, up to a maximumof 260 °C (500 °F).cold resistance down to approx. -200 °C (-328 °C).In evaluating the individual plastics, the interaction between the physicaland chemical load should always be taken into account.The various application possibilities and plastics grades must be testedbefore each individual application and, if need be, this must done bymeans of laboratory tests.5

Compensation for the"decrease in volume" fordumped packings1210Allowance (%)8642Allowance for compensation of decrease in volume020 30 40 50 60 70 80 90 100 110 120Diameter ratio D/dThe values indicated in the tables for dumped packings are valid for adiameter ratio vessel: packing size of D : d = 20.Since the arrangement of the packings is less compact near the vesselwall than in the interior of the bed, the number of packings per cubicmeter increases with the diameter ratio.The opposite diagram shows by which "allowance" the theoreticallycalculated vessel volume for diameter ratios of more than 20 must beincreased in order to completely fill the space required.If the plastic or metal packings are, for instance, thrown into the column,this may result in a further decrease in volume due to abnormallycompact packing.D = diameter of the vessel to be filledd = diameter or nominal size of the packings6

Generally applicablepressure drop diagram fortower packingsOptimum results with packed columns can only be obtained withwell-designed liquid distributors, support grids and hold-downgrids!Please note that this diagram no longer applies in case of foamingliquids.L = liquid flow rate kg/m 2 sL' = liquid flow rate kg/hG = gas flow rate kg/m 2 sG' = gas flow rate kg/hρ L= liquid density kg/m 3ρ G= gas density kg/m 3F = packing factor (see table)η = liquid viscosity mPa ⋅ sg = 9,81 = acceleration due to gravity m/s 21,00,4Spec. Pressure drop Δp/H in (Pa/m)[G 2 ⋅η 0,1 ⋅F] / [ρ G⋅(ρ L-ρ G)⋅g]0,30,20,10,040,030,020,01Δp/H=1200500300200100500,0040,0030,002200,0010,01 0,02 0,10,21,02,010(L/G)⋅[ρ G/(ρ L-ρ G)] 1/27

Tower packing factorTower packing factor F in 1/mTable 1Nominal size of the tower packingsTower packing Material 10 12½"15 19-20¾"251"30-35 381 ½"502"70-753"903 ½"RASCHIG Metal131 102 72 59 46 39 31SUPER-RING Plastic10540RALU-FLOW Plastic 75 38RASCHIG RING CeramicMetal3200128019009801250566840 510380340280310 210270 190120105PALL Ring Ceramic350 180 142MetalPlastic23032015717110314092 66825252RALU RING Metal15792 66Plastic13580 55 38TORUS SADDLE Ceramic 660 480 320 170 130 72 68SUPER TORUS Plastic 165 104 50SADDLEBERL SADDLE Ceramic 1500 790 560 360 220 150Table 2Sherwood-abscissa value x < 0.5 0.5 to 3.75 > 3.75Δ p = mm WS/m 40 80 125 40 80 125 40 80 125RASCHIG RING Ceramics25 x 338 x 450 x 5541302239508289239512295236574295226502269210472262203443246170394213164361197154RASCHIG RINGPALL RingTORUS SADDLEMetal25 x 1.638 x 1.650 x 1.6Metal25 x 0.638 x 0.850 x 0.9Ceramics1"1 1/2"2"51830823617098821641254722792331579592318161128466262217154927532117113145624619717712885174128400213177171118792991611123312131641741127230515710829213112514811269131102253141125138102662761281022201381211388966246115988

Tower packing factorThe graph shown on page 27 that is valid for all types of tower packingsand for mass system or operating conditions as well as Table 1 showingthe tower packing factors are based on a Sherwood correlation postulatedin 1938, which has been updated in accordance with the level ofengineering valid at the time.Table 1 shows the tower packing factors F in 1/m that constitute animportant characteristic parameter, seeing that the square root of thetower packing factor is inversely proportional to the gas flow rate of thepacked bed.This correlation can clearly be seen by taking the example of 50 mmPALL Rings made of metal with a tower packing factor of 66 and 2" = 50mm TORUS SADDLES made of ceramics with a tower packing factor of130. The tower packing factors show that the gas flow rate for metal PALLRings is 40 percent higher than for the TORUS SADDLES.GPall−Ring130= = 1,4G66Torus−SaddleThorough tests have shown that the tower packing factors indicated inTable 1 cannot be seen at constant values, but rather that they changewithin a certain range, depending on the load of the liquid or gas. Thetypes of tower packings which show the highest pressure drop, such asRASCHIG RINGS, also tend to change most with respect to their towerpacking factor.The tower packing factors in Table 1 can be consulted for planningcolumns. This results in column diameters that are somewhatoverdimensioned, especially in case of large flow rates of liquid andparticularly when RASCHIG RINGS are used.Table 2 shows that the fluctuation range of the tower packing factors F forfour different types of tower packings in the most common sizes as afunction of the abscissa value of the generally applicable pressure dropdiagram.1 2L ⎛ ρG⎞X =G⎜⎟⎝ ρL− ρG⎠Abscissa value of 3.75 and up are usually found only with absorptioncolumns and strippers; values of 0.5 and below occur with most distillationcolumns.9

Pressure drop with metalRALU-RINGSmixture water / airRALU-RING 25 mmRALU-RING 38 mm30003000Liquid velocity u L in (m 3 /m 2 h)Liquid velocity u L in (m 3 /m 2 h)2000u L =1251007550251002000u L =12510075502510010001000700700600600500500Spec. Pressure drop Δp/H (Pa/m)40030020010070Spec. Pressure drop Δp/H (Pa/m)4003002001007060605050404030302020Ralu Ring ® 25 mm in Metal100,1 0,2 0,3 0,4 0,5 0,6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )Ralu Ring ® 38 mm in Metal100,1 0,2 0,3 0,4 0,5 0,6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )10

Pressure drop with metalRALU-RINGSmixture water / airRALU-RING 50 mm30002000Liquid velocity u L in (m 3 /m 2 h)u L =1751501251007550251001000Spec. Pressure drop Δp/H (Pa/m)700600500400300200100706050403020Ralu Ring ® 50 mm in Metal100,1 0,2 0,3 0,4 0,5 0.6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )11

Pressure drop with plasticRALU-RINGSmixture water / airRALU-RING 25 mmRALU-RING 38 mm30003000Liquid velocity u L in (m 3 /m 2 h)Liquid velocity u L in (m 3 /m 2 h)20002000u L =12510075502510010001000u L =125100755025100700700600600500500Spec. Pressure drop Δp/H (Pa/m)40030020010070Spec. Pressure drop Δp/H (Pa/m)4003002001007060605050404030302020Ralu Ring ® 25 mm in Plastic100,1 0,2 0,3 0,4 0,5 0.6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )Ralu Ring ® 38 mm in Plastic100,1 0,2 0,3 0,4 0,5 0,6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )12

Pressure drop with plasticRALU-RINGSmixture water / airRALU-RING 50 mmRALU-RING 90 mm30003000Liquid velocity u L in (m 3 /m 2 h)Liquid velocity u L in (m 3 /m 2 h)20002000u L =125100755025100u L =22520017515012510075502510100001000700700600600500500Spec. Pressure drop Δp/H (Pa/m)40030020010070Spec. Pressure drop Δp/H (Pa/m)4003002001007060605050404030302020Ralu Ring ® 50 mm in Plastic100,1 0,2 0,3 0,4 0,5 0,6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )Ralu Ring ® 90 mm in Plastic100,1 0,2 0,3 0,4 0,5 0,6 1 2 3 4 5 6 103Gas capacity factor F V (m/s ⋅ kg/m )13

Absorption of CO 2 into NaOH forplastic RALU-RINGSValues calculated back to unused alkalinesolutionVol. Mass transfer coefficient k G⋅a (1/s)1,00,50,40,30,20,10,050,040,030,02Ralu Ring ® 15 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 15 mmDiameter: 290 mmPacked bed height: 1 mAlkaline solution concentration: 4%Gas concentration: approx. 1%Temperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)Vol. Mass transfer coefficient k G⋅a (1/s)1,00,50,40,30,20,10,050,040,030,02Ralu Ring ® 25 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 25 mmDiameter: 290 mmPacked bed height: 1 mAlkaline solution concentration: 4%Gas concentration: approx. 1%Temperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)14

Absorption of CO 2 into NaOH forplastic RALU-RINGSValues calculated back to unused alkalinesolutionVol. Mass transfer coefficient k G⋅a (1/s)1,00,50,40,30,20,10,050,040,030,02Ralu Ring ® 38 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 38 mmDiameter: 290 mmPacked bed height: 1 mAlkaline solution concentration: 4%Gas concentration: approx. 1%Temperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)Vol. Mass transfer coefficient k G⋅a (1/s)1,00,50,40,30,20,10,050,040,030,02Ralu Ring ® 50 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 50 mmDiameter: 400 mmPacked bed height: 1 mAlkaline solution concentration: 4%Gas concentration: approx. 1%Temperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)15

Absorption of CO 2 into NaOH forplastic RALU-RINGSValues calculated back to unused alkalinesolutionVol. Mass transfer coefficient k G⋅a (1/s)1,00,50,40,30,20,10,050,040,030,02Ralu Ring ® 90 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 90 mmDiameter: 400 mmPacked bed height: 1 mAlkaline solution concentration: 4%Gas concentration: approx. 1%Temperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)16

Desorption of oxygen from water forplastic RALU-RINGSinto a flow of nitrogenVol. Mass transfer coefficient k L⋅a (1/s)0,10,050,040,030,020,010,0050,0040,0030,002Ralu Ring ® 15 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 15 mmDiameter: 290 mmPacked bed height: 1 mTemperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)Vol. Mass transfer coefficient k L⋅a (1/s)0,10,050,040,030,020,010,0050,0040,0030,002Ralu Ring ® 25 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 25 mmDiameter: 290 mmPacked bed height: 1 mTemperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)17

Desorption of oxygen from water forplastic RALU-RINGSinto a flow of nitrogenVol. Mass transfer coefficient k L⋅a (1/s)0,10,050,040,030,020,010,0050,0040,0030,002Ralu Ring ® 38 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 38 mmDiameter: 290 mmPacked bed height: 1 mTemperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)Vol. Mass transfer coefficient k L⋅a (1/s)0,10,050,040,030,020,010,0050,0040,0030,002Ralu Ring ® 50 mm in Plastic3 4 51020 30 40 50100200 300RALU-RING 50 mmDiameter: 400 mmPacked bed height: 1 mTemperature: 20 °C (68 °F)Liquid velocity u L(m 3 /m 2 h)18

Desorption of oxygen from water forplastic RALU-RINGSinto a flow of nitrogenVol. Mass transfer coefficient k L. a (1/s)0,1Ralu Ring ® 90 mm in Plastic0,050,040,030,020,010,0050,0040,0030,0023 4 51020 30 40 50100200 300RALU-RING 90 mmDiameter: 400 mmPacked bed height: 1 mTemperature: 20 °C (68 °F)Liquid velocity u L (m 3 /m 2 h)19

Height of a transfer unit HTU OV forplastic RALU-RINGS 50 mmin the gaseous phase as a function of theirrigation density1,0.0,80,7HTU OV(m)0,60,50,40,30,22 3 4 5 6 71020 30 40 50Liquid velocity u L(m 3 /m 2 h)This graph shows the height necessary for the RALU RINGin the gaseous phase of a transfer unit as a function of theirrigation density for the F factors:F V= 1 (Pa 0,5 ) _ _ _ _ _andFV = 2 (Pa 0,5 ) _______ds = 300 mmH = 1350 mmSystem: air-NH 3/water20

Comparison graphRALU RING / PALL Ring in plasticSpecific pressure drop Δp/H asa function of the gas capacityfactor F VSpecific pressure dropΔp/NTU OVas a function of thegas capacity factor F V2000Liquid velocity u L in (m 3 /m 2 h)4003001000800700u L =252500200600500Spec. Pressure drop Δp/H (Pa/m)4003002001008070605040Spec. Pressure drop Δp/NTU OV (Pa/m)10090807060504030302020100,5 0,6 0,7 0,8 1,0 2,0 3,0 4,0 5,0 6,0Gas capacity factor F V (m/s ⋅3kg/m )100.6 0,7 0.8 0,9 1,02,0 3,0 4,0Gas capacity factor F V (m/s ⋅3kg/m )The graph shows the pressure droprelated to 1-meter packed bed height asa function of the gas capacity factor F V.The graph shows the differences in thedry and wet pressure drops between the50 mm PALL Ring and the 50 mm RALURING.ds = 750 mmH = 3000 mmirrigation rate u L(m³/m²h)_ _ _ _ _ PALL RING_______ RALU RINGThe graph shows the pressure dropwith respect to the number of transferunits as a function of the gas capacityfactor F V. The comparison of the plastic50 mm RALU RING and the 50 mmPALL Ring in plastic applies to thesystem air-NH 3/water at the irrigationrate of approx. 15 m³/m²h.ds = 300 mmH = 1350 mmu L10 ... 15 m³/(m³h)System: air-NH 3/water21