Intro to Plasma

Advanced Chemical Kinetics & Reaction Engineering

Plasma Chemical Engineering

CHE673Dr. Fahad Rehman

To integrate fundamental knowledge of chemical engineering, plasma physics and plasma chemistry to design of plasma reactors for chemical synthesis

Course objectives

Introduction to plasma, field equations, conservation equations, Boltzmann's equation, Debye shielding, Debye length, plasma sheath, collisions in plasmas, types of collisions, elementary reactions in plasma, LTE and non-LTE plasmas, breakdown processes in non-LTE plasmas, types of plasmas, atmospheric pressure glow discharges, Corona discharges, Dielectric barrier discharges, capacitively coupled plasmas, arc discharges, micro-discharges, Current-Voltage characteristics of DC and AC powered plasmas, Townsend mechanism of electrical breakdown, spark breakdown mechanism, Paschen curve, plasma- chemical kinetics, kinetics of O3 formation, Kinetics of H2 formation, plasma power supplies, impedance matching network, plasma diagnostics, plasma reactor design, plasma micro-reactors, ozone generator

Course Contents

Textbook:

Goldstone R. J., & Rutherford P.H., 1995, Introduction to Plasma Physics, IOP publishing.Fridman, A. A. & Kennedy, L. A. 2004. Plasma physics and engineering, CRC.Lieberman, M. A. & Lichtenberg, A. J. 2005. Principle of Plasma Discharge and Material Processing, John Wiley & Sons, Inc.Bellan, P. M. 2006. Fundamentals of plasma physics, Cambridge Univ Pr.Fridman, A. A. 2008. Plasma chemistry, Cambridge Univ Pr.

Plasma Chemical Engineering-We are the first one to studythis subject as a formal course in the class-not in COMSATS but in the Planet Earth

A Chemical Reaction

A Plasma Chemical Reaction

A Plasma Chemical Reaction

A Plasma Chemical Reaction

A Plasma Chemical Reaction

A Plasma Chemical Reaction

What is Plasma ? Greek word ()"anything formed or Mould.

First Used by Langmuir in 1929 for electrical discharges In a more rigorous way plasma could be defined as a quasi-neutral gas of charged and neutral particles characterised by a collective behaviour.

What is Plasma ? Greek word ()"anything formed or Mould.

First Used by Langmuir in 1929 for electrical discharges In a more rigorous way plasma could be defined as a quasi-neutral gas of charged and neutral particles characterised by a collective behaviour.

What is Plasma ? Greek word ()"anything formed or Mould.

First Used by Langmuir in 1929 for electrical discharges

Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal numbers so that the resultant space charge is very small. We shall use the name plasma to describe this region containingbalanced charges of ions and electrons.What is difference between Plasma and an ionised gas ?

What is Plasma ? In a more rigorous way plasma could be defined as a quasi-neutral gas of charged and neutral particles characterised by a collective behaviour.

How Plasma is Formed

1- By heating the matter

How Plasma is Formed 2- By applying the electric field

How Plasma is Formed 3. By Application of magnetic field

4. By application of microwave

5. By application of ultra sound...........

Fundamental Properties of Plasma 1. TemperatureElectron temperature Temperature of gas particlesExcitation temperature Rotational temperatureVibrational temperature

Would they be the same under Magnetic field ?

Number Density (m-3)

Electron number density ne

Gas particle density no

Degree of ionisation= ne/no

Magnetic Field (Tesla)

Classification of Plasma

Local thermal-equilibrium Plasma

Non local thermal-equilibrium Plasma

MSc- Research ProjectsLets work together!!!

Production of turbostratic carbon for the use in direct carbon fuel cell

Direct Carbon fuel cell

C + 2CO32- 3CO2 + 4e-(Anode)O2 + 2CO2 + 4e- 2CO32-(Cathode)

Uses a slurry of carbon particles in molten saltsFeed is distributed by entrainment in CO2 gasCO2 gas is evolved from the anode chamber

Turbostratic carbon

Atomic Planes arranged at diff. AnglesLots of Defects at the EdgesMore Space between the layers then that of Graphite

Samples= 3 biomass sample, 3 different coal or ??? Particle size ?Grinding before thermal processing or after?Heating time ?Heating rate?Temperature?Process variables

Analysis X-ray diffraction (XRD)

Scanning Electron microscopy (SEM)

Transmission electron microscopy (TEM)

XRD

TEM

Wastewater treatment with microbubbles

Flow rate of airDifferent types of pollutantsElectrophilic/nucleophilic (Phenol etc.,)Process variables

GC/MSAnalysis