ultrasonic application in chemical engineering
TRANSCRIPT
ULTRASONIC:Introduction & Application in Chemical
Engineering
Ananto Wimbaji
Exploring the Power of Sound
ULTRASONIC
Ultrasonic:Sound @ frequency > 20 kHz
Human hearing : 20 Hz – 20 kHzConventional Ultrasonic: 20 – 100 kHzExtended range of Sonochem: 20kHz-2MHzDiagnostic Ultrasonic: 5 – 10 MHz
Ultrasonic Application
Medical : diagnostic, corrective medicine
Engineering : measurement (flow, thickness, volume), welding
Chemical : Laboratory equipment cleaning
Biology : cell disruptionIndustrial : Welding, dispersion of ink
and pigment
Sonochemistry
Application of power of sound to chemical processes:
Ultrasound can increase chemical reactivity besides heat, pressure, light and catalyst
Chemical changes by power of ultrasound @lower frequency as a result of generated cavitation
Cavitations
Formation, growth & implosive collapse of bubbles in a liquid. Cavitational collapse produces intense local heating (~5000 K), high pressures (~ 1400 atm) , enormous heating & cooling rates (~>109 OK/sec) and liquid jet stream (~400 km/hr)
Cavitation
• Illustration of bubble generation and collapse
Occurrence of cavitations
• Within the bubble itself which can be thought of microreactor
• In liquid region immediately adjacent to bubble where the temperature are not so great
• In the immediate vicinity of bubble when shockwave produce on collapse will create enormous shear force
Chemical Synthesis
Type of chemical synthesis of ultrasonic:
- Reactions involving Metal or Solids Surface
- Reactions involving powder and particulate matter
- Emulsions reaction- Homogeneous reaction
Rule of Sonochemistry
Luche,JL formulated empirical rule of sonochemistry:
Possible Benefit of Ultrasonic for Chemistry
- Might accelerate reaction or only required less forcing condition
- Induction period are often significantly reduced as are exothermic normally associated with such reactions
- Reactions are often initiated by ultrasound without the need for additives
- The number of steps that are normally required can sometime be reduced
- A reaction can be directed to alternative pathway
Sonochemistry Apparatus
Generator
Transducer
Reaction chamber
Sonoprobe / horn
In Lab /development :
Courtesy: Telsonic Ultrasonic
Sonochemistry Apparatus
In industry
Courtesy: Hielscher Ultrasound Technology
Current Application
Cavitation & Biodiesel
• (Trans)-esterification of vegetable oil by alcohol can be assisted with ultrasound
• Reaction carried out in near ambient condition, can yielded > 98% in significantly lower reaction time(~15 min) and possible to use only little excess of alcohol
• Power required are significantly lower that conventional reaction
Biodiesel Process
Hielscher Ultrasound Technology
Ultrasonic Compare to Other Technique
Reference
• Sarpong,R, “Ultrasound Applications in Organic Synthesis”, Stoltz Literature Meeting,2003
• Mason,TJ & Lorimer,JP,”Applied Sonochemistry: Uses of Power Ultrasound in Chemistry and Processing”, Wiley VCH,2002
• Jones,C, “ Sonochemistry Group”, Royal Society of Chemist Presentation,England
• Gogate,P et.al,”Cavitation: A technology on the horizon” Current Science,Vol 91 No 1, 2006
LET’S CAVIT 8