Chemical engineering

Process engineers design, construct and operate plants

Chemical engineering is the branch of engineering that deals with the application of physical science (e.g., chemistry and physics), and life sciences (e.g., biology, microbiology and biochemistry) with mathematics , to the process of converting raw materials or chemicals into more useful or valuable forms. In addition to producing useful materials, modern chemical engineering is also concerned with pioneering valuable new materials and techniques - such as nanotechnology, fuel cells and biomedical engineering.^[1] Chemical engineering largely involves the design, improvement and maintenance of processes involving chemical or biological transformations for large-scale manufacture. Chemical engineers ensure the processes are operated safely, sustainably and economically. Chemical engineers in this branch are usually employed under the title of process engineer. A related term with a wider definition is chemical technology. A person employed in this field is called a chemical engineer.

Chemical engineering timeline

In 1824, French physicist Sadi Carnot, in his "On the Motive Power of Fire", was the first to study the thermodynamics of combustion reactions in steam engines. In the 1850s, German physicist Rudolf Clausius began to apply the principles developed by Carnot to chemical systems at the atomic to molecular scale.^[2] During the years 1873 to 1876 at Yale University, American mathematical physicist Josiah Willard Gibbs, the first to be awarded a Ph.D. in engineering in the U.S., in a series of three papers, developed a mathematical-based, graphical methodology, for the study of chemical systems using the thermodynamics of Clausius. In 1882, German physicist Hermann von Helmholtz, published a founding thermodynamics paper, similar to Gibbs, but with more of an electro-chemical basis, in which he showed that measure of chemical affinity, i.e., the "force" of chemical reactions, is determined by the measure of the free energy of the reaction process. The following timeline shows some of the key steps in the development of the science of chemical engineering:^[3]

• 1805 – John Dalton published Atomic Weights, allowing chemical equations to be balanced and the basis for chemical engineering mass balances.
• 1882 – a course in "Chemical Technology" is offered at University College London
• 1883 – Osborne Reynolds defines the dimensionless group for fluid flow, leading to practical scale-up and understanding of flow, heat and mass transfer
• 1885 – Henry Edward Armstrong offers a course in "chemical engineering" at Central College (later Imperial College), London.
• 1888 – There is a Department of Chemical Engineering at Glasgow and West of Scotland Technical College offering day and evening classes.^[4]
• 1888 – Lewis M. Norton starts a new curriculum at Massachusetts Institute of Technology (MIT): Course X, Chemical Engineering^[5][6]
• 1889 – Rose Polytechnic Institute awards the first bachelor's of science in chemical engineering in the US.^[7]
• 1891 – MIT awards a bachelor's of science in chemical engineering to William Page Bryant and six other candidates.
• 1892 – A bachelor's program in chemical engineering is established at the University of Pennsylvania.
• 1898 – Bachelor of science program in chemical engineering is established at the University of Michigan.
• 1901 – George E. Davis produces the Handbook of Chemical Engineering
• 1905 – the University of Wisconsin awards the first Ph.D. in chemical engineering to Oliver Patterson Watts.
• 1908 – the American Institute of Chemical Engineers (AIChE) is founded.
• 1922 – the UK Institution of Chemical Engineers (IChemE) is founded.^[8]

Applications

Chemical engineering is applied in the manufacture of a wide variety of products. The chemical industry has a large scope, manufacturing inorganic and organic industrial chemicals, ceramics, fuels and petrochemicals, agrochemicals (fertilizers, insecticides, herbicides), plastics and elastomers, oleochemicals, explosives, detergents and detergent products (soap, shampoo, cleaning fluids), fragrances and flavors, additives, dietary supplements and pharmaceuticals. Closely allied or overlapping disciplines include wood processing, food processing, environmental technology, and the engineering of petroleum, glass, paints and other coatings, inks, sealants and adhesives. Other applications of a chemical engineers knowledge include the vital Bosch-Haber process. This falls under the term ‘process engineer’ mentioned before and the process yields chemical ammonia used in fertilizers, explosive, nylon, and plastics. A variety of substances found in everyday life have been made under the supervision of a chemical engineer.

Overview

Chemical engineers design processes to ensure the most economical operation. This means that the entire production chain must be planned and controlled for costs. A chemical engineer can both simplify and complicate "showcase" reactions for an economic advantage. Using a higher pressure or temperature makes several reactions easier; ammonia, for example, is simply produced from its component elements in a high-pressure reactor. On the other hand, reactions with a low yield can be recycled continuously, which would be complex, arduous work if done by hand in the laboratory. It is not unusual to build 6-step, or even 12-step evaporators to reuse the vaporization energy for an economic advantage. In contrast, laboratory chemists evaporate samples in a single step.

The individual processes used by chemical engineers (e.g., distillation or filtration) are called unit operations and consist of chemical reactions, mass-, heat- and momentum- transfer operations. Unit operations are grouped together in various configurations for the purpose of chemical synthesis and/or chemical separation. Some processes are a combination of intertwined transport and separation unit operations, (e.g., reactive distillation).

Three primary physical laws underlying chemical engineering design are conservation of mass, conservation of momentum and conservation of energy. The movement of mass and energy around a chemical process are evaluated using mass balances and energy balances, laws that apply to discrete parts of equipment, unit operations, or an entire plant. In doing so, chemical engineers must also use principles of thermodynamics, reaction kinetics, fluid mechanics and transport phenomena. The task of performing these balances is now aided by process simulators, which are complex software models (see List of Chemical Process Simulators) that can solve mass and energy balances and usually have built-in modules to simulate a variety of common unit operations.

Modern chemical engineering

The modern discipline of chemical engineering encompasses much more than just process engineering. Chemical engineers are now engaged in the development and production of a diverse range of products, as well as in commodity and specialty chemicals. These products include high performance materials needed for aerospace, automotive, biomedical, electronic, environmental, space and military applications. Examples include ultra-strong fibers, fabrics, dye-sensitized solar cells, adhesives and composites for vehicles, bio-compatible materials for implants and prosthetics, gels for medical applications, pharmaceuticals, and films with special dielectric, optical or spectroscopic properties for opto-electronic devices. Additionally, chemical engineering is often intertwined with biology and biomedical engineering. Many chemical engineers work on biological projects such as understanding biopolymers (proteins) and mapping the human genome. The line between chemists and chemical engineers is growing ever more thin as more and more chemical engineers begin to start their own innovation using their knowledge of chemistry, physics and mathematics to create, implement and mass produce their ideas.

Related fields and topics

Today, the field of chemical engineering is a diverse one, covering areas from biotechnology and nanotechnology to mineral processing.

Additional topics under the title AIChE's Technical Divisions and Forums in American Institute of Chemical Engineers

See also

References

Further reading

• Bird, R.B., Stewart, W.E. and Lightfoot, E.N. (August 2001). Transport Phenomena (Second ed.). John Wiley & Sons. ISBN 0-471-41077-2. 
• Chopey, Nicholas P. (2004). Handbook of Chemical Engineering Calculations (3rd ed.). McGraw-Hill. ISBN 0071362622. 
• Coulson J. M. ; Richardson J. F. ; Backhurst J. R. ; Harker J. H. (1991). Chemical engineering. Volume 2 : Particle technology and separation processes (2nd ed.). Pergamon Press - New York. 
• Green, Don W. and Perry, Robert H. (deceased) (2008). Perry's Chemical Engineers' Handbook (8th ed.). McGraw-Hill. ISBN 0-07-049841-5. 
• Himmelbau, David M. (1996). Basic Principles and Calculations in Chemical Engineering (6th ed.). Prentice-Hall. ISBN 0133057984. 
• King, C.J. (1980). Separation Processes (2nd ed.). McGraw Hill. ISBN 0-07-034612-7. 
• Kister, Henry Z. (1992). Distillation Design (1st ed.). McGraw-Hill. ISBN 0-07-034909-6. 
• Kletz, Trevor (1999). HAZOP and HAZAN (4th ed.). Taylor & Francis. ISBN 0-85295-421-2. 
• Kroschwitz, Jacqueline I.; Seidel, Arza (editors) (2004). Kirk-Othmer Encyclopedia of Chemical Technology (5th ed.). Hoboken, NJ: Wiley-Interscience. ISBN 0-471-48810-0. 
• Lees, Frank (2005). Loss Prevention in the Process Industries (3rd ed.). Elsevier. ISBN 978-0-7506-7555-0. 
• Levenspiel, O.: The Chemical Reactor Omnibook, Osu, Oregon, 1993
• McCabe, W., Smith, J. and Harriott, P. (2004). Unit Operations of Chemical Engineering (7th ed.). McGraw Hill. ISBN 0-07-284823-5. 
• Seader, J. D., and Henley, Ernest J. (1998). Separation Process Principles. New York: Wiley. ISBN 0-471-58626-9. 
• Servos, John W., Physical chemistry from Ostwald to Pauling : the making of a science in America, Princeton, N.J. : Princeton University Press, 1990. ISBN 0691085668