agitation equipment - table 4.16 short residence time pumps, inline mixers pipes static mixers ...
TRANSCRIPT
![Page 1: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/1.jpg)
Agitation Equipment - Table 4.16 Short residence time
pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices homogenizers
Good design requires expertise
Long residence time
stirred tanks
(very long pipes)
Design is generally more forgiving
![Page 2: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/2.jpg)
Stirred Tanks are used for: liquid blending liquid liquid dispersion (drop break up)solids suspension and dissolutiongas dispersion reaction, including bioreactionssolids leachingcrystallization
![Page 3: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/3.jpg)
Generic TankDriveSealShaft+impeller Internals
baffles dip pipe coils/jacket
![Page 4: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/4.jpg)
Typical dimensionsTank height per impeller<1.2T
T=tank diameter 0.5m<T<20m H=total fluid height
Impeller diameter (0.2T<D<0.5T) Impeller off bottom clearance
(0.25T<C<0.4T; up to 0.5T for radial)4 Baffles
baffle width=T/10 (m) or T/12 (feet)
![Page 5: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/5.jpg)
The Importance of BafflesBaffles convert swirl to axial circulation
and macro-scale mixing
![Page 6: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/6.jpg)
The Importance of Dip PipesFeed at the impeller for intense, rapid
mixing and fast reactionFeed below the impeller (ALWAYS!) for
gas dispersionFeed at the impeller for consistent
product quality
![Page 7: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/7.jpg)
Impellers:Radial Axial
![Page 8: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/8.jpg)
Reynolds Number, ReReynolds number is more general than
viscosityLimits for an impeller:
laminar flow if Re<200-400 - special eqmt AVOID 400<Re<20000 turbulent if Re>2x104
D=impeller diameterN=rotational speed, rps
2ND
Re
![Page 9: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/9.jpg)
Turbulent Power Number, NpUsed to calculate power draw, P
Np=3.5 for the “best practice” radial impeller, the CD6 by Chemineer
Np=1.3 for the generic axial impeller, the PBT
Np=0.3 for high efficiency axial impellers
53DN
PNp
![Page 10: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/10.jpg)
Sizing: Shortcut Design UlrichTable 4.16 in Ulrich gives ranges of
power required for various applications eg liquid liquid dispersion, mild agitation,
P(kW)=0.25V0.8 where V is in m3
Ulrich scales propellers as PV axial impellers as PV0.8
radial impellers as PVAll of these refer to the tank volume
![Page 11: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/11.jpg)
How accurate is short cut design?Equation for blending in Ulrich
Current best practice equation (Grenville, 1995)
Where will Ulrich fail?
5.1
3
5.0
m1
V
P
V12000
2
3/1p D
T
NN
2.55
![Page 12: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/12.jpg)
Extrapolation fails: 40x to 500x to 10000x
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+01 1.E+03 1.E+05 1.E+07 1.E+09
Re
Res
iden
ce t
ime
(s)
PBT/water/2m tank
A310/water/2m tank
RT/water/2m tank
PBT/20m tank
PBT/large impeller
PBT/high viscosity
PBT/0.24m tank
Ulrich
![Page 13: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/13.jpg)
Normal Range of Operation: 4x
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05 1.E+06 1.E+07
Re
Res
iden
ce t
ime
(s)
PBT/water/2m tank
A310/water/2m tank
RT/water/2m tank
PBT/large impeller
Ulrich
![Page 14: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/14.jpg)
Sizing: Shortcut Design KrestaMaintain geometric similarity
(D/T, C/T etc) on scale-upScale with constant P/Vtank for ALL
impellers; use P values from UlrichCall me for info. on detailed designs!Coming soon:
The Industrial Mixing Handbook
![Page 15: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/15.jpg)
Short Cut GeometryPBT impeller, Np=1.3 (T=2m); D=T/3; C=T/3Standard gear boxes give output
speeds of 25, 30, 45, 56, 68, 84, 100 and 125 rpm, based on a 1750 rpm motor
A variable speed drive costs more - but is cheap insurance if you don’t know the real answer
![Page 16: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/16.jpg)
Critical Design VariablesTank size is a function of process scale
and residence time: this is the key cost variable for the vessel
The drive cost is fixed by the power and torque: Ulrich considers only the power
Three variables define the mixing operation in the detailed design stage: Impeller geometry Impeller diameter, D Rotational speed, N
![Page 17: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/17.jpg)
Costing: The AgitatorFigure 5.42: the drive, coupling, shaft
and impellerCost is a strong function of the seal
open tank<stuffing box<mechanical seal
CBM=CpxFBM
all data for the agitator is on one figure
![Page 18: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/18.jpg)
Costing: The Tank
For No Heat TF 98% vertical Size by height Figures
5-44 - size (CP)
5-45 - pressure (FP) and material (FM)
5-46 - FBM=f(FMxFP)
CBM=CPxFBM
With Heat TF Size by volume Figure 5.23 All factors in one
figure
![Page 19: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/19.jpg)
Recap: Tanks vs. PipesTanks are flexible where there is
uncertainty in designTanks allow long residence timesStirred tanks are cheap
Caveat: A poor mixing design lead to start up problems which cost many times more than the equipment itself!!!
![Page 20: Agitation Equipment - Table 4.16 Short residence time pumps, inline mixers pipes static mixers extruders T-junctions valves and orifices](https://reader035.vdocument.in/reader035/viewer/2022062516/56649dac5503460f94a9c405/html5/thumbnails/20.jpg)
Mixing Equipment - free gift Recommend
stirred tanks static mixers T- mixers jet mixers generic PBT for easy
jobs wide range of well
designed impellers for a variety of difficult jobs
Avoid if possible bubble columns glass lined vessels propellers retreat blade impellers in-line mixers side mounted mixers