the basic science for chemical industries
Chemistry
Chemical Engineer’s function:
Chemical Engineer’s goal:
To have the conversion equal the yield
– fraction of raw material recovered as the main (desired) product
– the most important single factor in cost
Yield
– fraction changed to something else, whether products or by-products
– indicates the amount changed by a single pass through an apparatus when multiple passes are used
Conversion
Lower conversions =
larger plant size
Higher operating pressure =
greater yields but higher equipment costs
Faster reaction time =
closer approach to equilibrium, but requires larger, more expensive equipment
Improved catalysts =
shorter reaction time, but equilibrium remains unaffected
Kinetics
are materials that increase reaction speed
Catalysts
The Haber-Bosch Process
provide a perfectly porous and high surface area material for the reaction
Iron (Fe) catalyst
Costs are most strongly affected by
material use and distribution
Material Balance
is an energy-intensive industry
Chemical processing
Goal of chemical processing
towards reducing energy use
provide data on all phases of technical reactions
Thermodynamics
performing of an industrial process on material in batches of a limited quantity or number
Batch process
process where product comes out without interruption and not in groups
Continuous process
is a graphical representation of a process, coordinating the sequence of unit operations and unit processes
Flowchart
show material and energy flows and operating conditions
Simple blocks
show everything in a process and become extremely complicated
More elaborate blocks
show details, ex. fire lines, instruments & control systems, air lines, drains, etc.
Special blocks