Ultrasonic Application in Chemical Engineering

ULTRASONIC: Introduction & Application in Chemical Engineering Ananto Wimbaji Exploring the Power of Sound

ULTRASONIC
Ultrasonic:
Sound @ frequency > 20 kHz
Human hearing : 20 Hz – 20 kHz
Conventional Ultrasonic: 20 – 100 kHz
Extended range of Sonochem: 20kHz-2MHz
Diagnostic Ultrasonic: 5 – 10 MHz

Ultrasonic Application
Medical : diagnostic, corrective medicine
Engineering : measurement (flow, thickness, volume), welding
Chemical : Laboratory equipment cleaning
Biology : cell disruption
Industrial : 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 O K/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

Ultrasonic Application in Chemical Engineering

by wimbaji

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