18CH34 Mechanical Operations syllabus for CH

PARTICLE TECHNOLOGY:

Particle shape, particle size, different ways of expression of particle size, shape factor, sphericity, particle size analysis, screens – ideal and actual screens, Differential and cumulative size analysis, effectiveness of screen, Specific surface of a mixture of particles, Number of particles in a mixture, standard screens, Industrial screening equipment, Motion of screen, Grizzly, Gyratory screen, Vibrating screen, Trommels.

SIZE REDUCTION:

Introduction – types of forces used for comminution, Criteria for comminution, Characteristics of comminuted products, Laws of size reduction, Work Index, Energy utilization, methods of operating crushers – Free crushing, choke feeding, open circuit grinding, Closed circuit grinding, wet and dry grinding, Equipment for size reduction – Classification of size reduction equipment, equipment – Blake jaw crusher, Gyratory crusher, Smooth roll crusher, Toothed roll crusher, impactor, Ball mill, Critical speed of ball mill, Cutters – Knife cutter.

FLOW OF FLUID PAST IMMERSED BODIES:

Drag, Drag coefficient, Pressure drop – Kozeny-Carman equation, Blake-Plummer, Ergun equation, Fluidization, conditions for fluidization, Minimum fluidization velocity, Pneumatic conveying.

MOTION OF PARTICLES THROUGH FLUIDS:

Mechanics of particle motion, Equation for one dimensional motion of particles through a fluid in gravitational and centrifugal field, Terminal velocity, Drag coefficient, Motion of spherical particles in Stoke’s region, Newton’s region, and Intermediate region, Criterion for settling regime, Hindered settling, Modification of equation for hindered settling, Centrifugal separators, Cyclones and Hydro cyclones.

SEDIMENTATION:

Batch settling test, Coe and Clevenger theory, Kynch theory, thickener design.

FILTRATION:

Introduction, Classification of filtration, Cake filtration, Clarification, batch and continuous filtration, Pressure and vacuum filtration, Constant rate filtration and cake filtration, Characteristics of filter media, Industrial filters, Sand filter, Filter press, Leaf filter, Rotary drum filter, Centrifugal filtration – Suspended batch centrifuge, Filter aids, Application of filter aids, Principles of cake filtration.

AGITATION AND MIXING:

Application of agitation, Agitation equipment, Types of impellers – Propellers, Paddles and Turbines, Flow patterns in agitated vessels, Prevention of swirling, Standard turbine design, Power correlation and power calculation, Mixing of solids, Types of mixers –, Muller mixers, Mixing index, Ribbon blender, Internal screw mixer.

SAMPLING, STORAGE AND CONVEYING OF SOLIDS:

Sampling of solids, Storage of solids, Open and closed storage, Bulk and bin storage, Conveyors – Belt conveyers, Chain conveyor, Apron conveyor, Bucket conveyor, Screw conveyor.

MISCELLANEOUS SEPARATION:

Magnetic separation, Electrostatic separation, Jigging, Heavy media separation, Froth floatation process.

Course Outcomes:

On completion of this course the students will be able to

• Apply principles of screen analysis, equivalent diameters to samples. Comprehend applications of Standard Sieve Series, concepts of ideal and actual screens and Screening equipment.
• Comprehend the forces and laws of size reduction and explain the working principle of size reduction equipment.
• Comprehend flow of fluids through solid beds and apply the same to filtration.
• Deduce expression for power requirements in agitation and mixing and compare different mixing devices.
• Comprehend different sampling techniques and solids conveying machinery.
• Explain principle of size separation in Magnetic, Electrostatic, Froth Floatation techniques and size enlargement techniques.

QUESTION PAPER PATTERN:

• The question paper will have ten questions.
• Each full Question consisting of 20 marks
• There will be 2 full questions (with a maximum of four sub questions) from each module.
• Each full question will have sub questions covering all the topics under a module.
• The students will have to answer 5 full questions, selecting one full question from each module.

TEXT BOOKS:

1. McCabe, W.L., et.al., “Unit Operations in Chemical Engineering”, 5thedn., McGraw Hill International, Singapore, 2000

2. Badger W.L. and Banchero J.T., “Introduction to Chemical Engineering”, 3rdedn. Tata McGraw Hill International Edition, Singapore , 1999

3. Coulson J.H. and Richardson J.F., “Coulson and Richardson’s Chemical Engineering”, Vol-II Particle Technology and Separation Process, 6thedn., Asian Books (p) Ltd., New Delhi, 1998

REFERENCE BOOKS:

1. Brown G.G., et.al., “Unit Operations”, 1st edn., CBS Publisher, New Delhi, 1995

2. Foust A.S., et.al., “Principles of Unit Operations”, 3rd edn., John Wiley and Sons, New York, 1997