Chemical Processing - April 2008 - (Page 32) >> High shear workhead Figure 3. This unit features fine emulsor screens with circular holes but a variety of other hole types are available for other applications. measure the total energy, í µí»†, supplied to the mixture. This is estimated by the formula: í µí»† = PFluid/V (1) where V is the volume of the mix (m3) and PFluid is the total power expended to the fluid (W), calculated from torque data as P = 2Ï€NT, with N being the rotational speed (rev/s) and T (N.m) the torque value. Rotor tip speed. Vtip (m/s) can be used to assess the kinetic energy imparted to the process fluid from the tip of the rotor blade as well as in calculating the shear stress and rates imparted to the fluid: Vtip = Ï€ND (2) where N is the rotational speed (rev/s) and D is the rotor diameter (m). Tip speed plays a major role in determining the shear rate in the gap between the rotor and stator, γgap (s-1). This is where shear rates are maximized, therefore quantifying the activity in this region is of considerable importance in predicting the performance of equivalent machines across a range of sizes in scale-up. We can estimate the value for the shear rate in the shear gap via: γgap = Vtip/δ (3) where δ is the shear gap (m). The γgap will become more significant at higher viscosities because the velocity gradient will increase. At lower viscosities the flow patterns in the gap won’t exhibit simple shear flow and will become more turbulent — in which case 32 • March 2008 www.chemicalprocessing.com http://www.planttriage.com http://www.planttriage.com http://www.chemicalprocessing.com
Table of Contents Feed for the Digital Edition of Chemical Processing - April 2008 Chemical Processing - April 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Is It a Tragedy or Comedy for Engineers? Better Understanding Boosts Mixer Scale-up Don't Err With Air Compressors Control Performance Supervision Enhances Revamp Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds Ad Index End Point Chemical Processing - April 2008 Chemical Processing - April 2008 - Chemical Processing - April 2008 (Page Cover1) Chemical Processing - April 2008 - Chemical Processing - April 2008 (Page Cover2) Chemical Processing - April 2008 - Chemical Processing - April 2008 (Page 3) Chemical Processing - April 2008 - Chemical Processing - April 2008 (Page 4) Chemical Processing - April 2008 - Contents (Page 5) Chemical Processing - April 2008 - Contents (Page 6) Chemical Processing - April 2008 - From the Editor (Page 7) Chemical Processing - April 2008 - From the Editor (Page 8) Chemical Processing - April 2008 - ChemicalProcessing.com (Page 9) Chemical Processing - April 2008 - ChemicalProcessing.com (Page 10) Chemical Processing - April 2008 - Field Notes (Page 11) Chemical Processing - April 2008 - Field Notes (Page 12) Chemical Processing - April 2008 - In Process (Page 13) Chemical Processing - April 2008 - In Process (Page 14) Chemical Processing - April 2008 - In Process (Page 15) Chemical Processing - April 2008 - In Process (Page 16) Chemical Processing - April 2008 - Energy Saver (Page 17) Chemical Processing - April 2008 - Energy Saver (Page 18) Chemical Processing - April 2008 - Compliance Advisor (Page 19) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 20) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 21) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 22) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 23) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 24) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 25) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 26) Chemical Processing - April 2008 - Is It a Tragedy or Comedy for Engineers? (Page 27) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 28) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 29) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 30) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 31) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 32) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 33) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 34) Chemical Processing - April 2008 - Better Understanding Boosts Mixer Scale-up (Page 35) Chemical Processing - April 2008 - Don't Err With Air Compressors (Page 36) Chemical Processing - April 2008 - Don't Err With Air Compressors (Page 37) Chemical Processing - April 2008 - Don't Err With Air Compressors (Page 38) Chemical Processing - April 2008 - Don't Err With Air Compressors (Page 39) Chemical Processing - April 2008 - Don't Err With Air Compressors (Page 40) Chemical Processing - April 2008 - Control Performance Supervision Enhances Revamp (Page 41) Chemical Processing - April 2008 - Control Performance Supervision Enhances Revamp (Page 42) Chemical Processing - April 2008 - Control Performance Supervision Enhances Revamp (Page 43) Chemical Processing - April 2008 - Control Performance Supervision Enhances Revamp (Page 44) Chemical Processing - April 2008 - Process Puzzler (Page 45) Chemical Processing - April 2008 - Process Puzzler (Page 46) Chemical Processing - April 2008 - Process Puzzler (Page 47) Chemical Processing - April 2008 - Plant InSites (Page 48) Chemical Processing - April 2008 - Equipment & Services (Page 49) Chemical Processing - April 2008 - Equipment & Services (Page 50) Chemical Processing - April 2008 - Equipment & Services (Page 51) Chemical Processing - April 2008 - Product Spotlight/Classifieds (Page 52) Chemical Processing - April 2008 - Product Spotlight/Classifieds (Page 53) Chemical Processing - April 2008 - Product Spotlight/Classifieds (Page 54) Chemical Processing - April 2008 - Product Spotlight/Classifieds (Page 55) Chemical Processing - April 2008 - Product Spotlight/Classifieds (Page 56) Chemical Processing - April 2008 - Ad Index (Page 57) Chemical Processing - April 2008 - End Point (Page 58) Chemical Processing - April 2008 - End Point (Page Cover3) Chemical Processing - April 2008 - End Point (Page Cover4)
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.