Selon Wikipedia:

Le génie chimique, ou génie des procédés physico-chimiques, désigne l’application de la chimie physique à l’échelle industrielle. Elle a pour but la transformation de la matière dans un cadre industriel et consiste en la conception, le dimensionnement et le fonctionnement d’un procédé comportant une ou plusieurs transformations chimiques et/ou physiques. Les méthodes utilisées dans un laboratoire ne sont souvent pas adaptées à la production industrielle d’un point de vue économique et technique. Le génie chimique permet ainsi le passage d’une synthèse de laboratoire à un procédé industriel de même que son fonctionnement dans le respect des contraintes économiques, techniques, environnementales et de sécurité.

Le génie chimique se situe à la convergence de plusieurs disciplines et étudie les transformations, les transports et les transferts de la matière, de l’énergie et de la quantité de mouvement pour établir des lois et des corrélations utilisables lors de la transposition ou de l’extrapolation à l’échelle industrielle.

C’est quoi la chimie physique?

La chimie physique est l’étude des bases physiques des systèmes chimiques et des procédés. En particulier, la description énergétique des diverses transformations fait partie de la chimie physique. On y trouve des disciplines importantes comme la thermodynamique chimique (ou thermochimie), la cinétique chimique, la mécanique statistique, la spectroscopie et l’électrochimie.

Sont comptés parmi les phénomènes que la chimie physique essaie d’expliquer :

1. les forces intermoléculaires qui déterminent les propriétés physiques des matériaux, telles la déformation plastique des solides et la tension superficielle des solides ;
2. la cinétique chimique et la vitesse de réaction ;
3. les propriétés des ions et la conductivité électrique des matériaux ;
4. la chimie des surfaces et l’électrochimie des membranes ;
5. la thermochimie : le transfert de chaleur, et plus généralement les échanges d’énergie, entre un système chimique et son environnement lors d’une transition de phase ou d’une réaction chimique ;
6. les propriétés colligatives et leur emploi pour déterminer le nombre de particules en solution ;
7. les nombres de phases, composantes et de degrés de liberté peuvent être reliés selon la règle des phases de Gibbs ;
8. l’électrochimie et les piles électriques.

C’est quoi un procédé chimique?

En chimie, un procédé chimique est une méthode ou un moyen de modifier la composition d’une ou de plusieurs molécules. Ce procédé peut survenir naturellement ou artificiellement et exige une réaction chimique.

En ingénierie, un procédé chimique est une méthode de fabrication employée à l’échelle industrielle dans le but de modifier la composition chimique de substances ou de matériaux. Ces méthodes se retrouvent principalement dans l’industrie chimique.

Aucune de ces définitions n’est exacte ou complète, car il est difficile de connaître ce qu’est précisément un procédé : ce sont des définitions pratiques. Il y a également un recoupement entre ces deux définitions. À cause de cette inexactitude, les chimistes et d’autres scientifiques utilise le terme « processus chimique » dans un sens général ou selon l’interprétation donnée en ingénierie. Cependant, les ingénieurs utilise ce terme régulièrement. L’article se concentre surtout sur la définition ingénierie.

Pour compléter une transformation chimique, une ou plusieurs étapes sont nécessaires : chaque étape est appelée opération unitaire. Dans une usine chimique, chaque opération unitaire survient habituellement dans un seul récipient ou dans des sections nommées « unités ».

Souvent, une ou plusieurs réactions chimiques surviennent, mais il est possible de modifier la composition d’un matériau par séparation, purification ou conditionnement.

Les étapes peuvent s’effectuer séquentiellement dans le temps ou dans l’espace alors que des matériaux circulent dans une unité. Pour une certaine quantité de réactifs ou de produits, la quantité de matériau peut être calculée aux étapes clés du procédé en se basant sur des données empiriques ou en établissant des bilans de matériau. Ces quantités peuvent être diminuées ou augmentées selon la capacité de production d’une usine. Une ou plusieurs usines peuvent fabriquer le même produit, chacune selon ses capacités et en fonction de la demande.

Ces procédés chimiques peuvent être exprimés par des schémas fonctionnels de flux ou avec plus de détails par des schémas de procédé.

En plus d’être utilisés dans des usines chimiques, les procédés chimiques sont aussi utilisés dans les raffineries, dans les sites de traitement du gaz naturel, dans les sites de fabrication des polymères et de médicaments, ainsi que dans les usines de traitement des eaux. Les aliments produits à grande échelle sont souvent fabriqués à partir de produits ayant subi un ou plusieurs traitements de nature chimique.

C’est quoi une opération unitaire?

Une opération unitaire est une subdivision d’un procédé industriel qui consiste en général en une opération physique ou chimique. est une opération où est réalisée une seule transformation chimique ou l’extraction d’un constituant d’une solution par une seconde phase (liquide ou gazeuse) ou la séparation physique de constituants d’un mélange (distillation d’un mélange liquide) ou d’une suspension (par exemple la filtration)

Deuxième définition: De la matière première au conditionnement du produit fini, toute production physique et /ou chimique fait appel, quelle que soit l’échelle, à une suite coordonnée d’opérations fondamentales distinctes et indépendantes du procédé lui-même, appelées « opérations unitaires ». Tout procédé peut se ramener à une combinaison d’un nombre restreint d’opérations unitaires.

Typologie

On peut classer les opérations unitaires en trois grandes classes :

1. préparation, conditionnement et acheminement des matières premières (réactifs) ;
2. transformation chimique des réactifs en produits ;
3. séparation, purification et conditionnement des produits.

Exemples

Voici une liste d’opérations unitaires :

• Transport de fluides / transfert thermique sur des fluides :
  • Écoulements : pompage, mesure, stockage
  • Mélange : agitation, turbulence
  • Transfert : thermique
  • Changement de phase : évaporation, condensation, fusion, cristallisation, sublimation
• Matière divisée :
  • Réduction de taille typique des objets : broyage, dispersion, gouttes/bulles
  • Augmentation de taille typique des objets : frittage, agrégation, enrobage, coalescence
  • Transport : d’une suspension, émulsion ou brouillard
  • Perméation : lit fixe, lit fluidisé, chromatographie, percolation
  • Séparation liquide/solide : séparation membranaire, sédimentation, tamisage, centrifugation, séchage
  • Séparation gaz/solide : cyclone
• Fractionnement de mélanges moléculaires :
  • Par transfert : distillation, extraction, absorption, échange d’ions, sublimation, condensation fractionnée, cristallisation, fusion fractionnée
  • Par transport : électromigration, électrophorèse, diffusion, sédimentation

Exemple de procédé industriel avec les opérations unitaires le constituant:

C’est quoi le génie chimique?

Selon Wikipedia (en anglais):

Chemical engineering is a branch of engineering that uses principles of chemistry, physics, mathematics, biology, and economics to efficiently use, produce, design, transport and transform energy and materials. The work of chemical engineers can range from the utilisation of nano-technology and nano-materials in the laboratory to large-scale industrial processes that convert chemicals, raw materials, living cells, microorganisms, and energy into useful forms and products.

Chemical engineers are involved in many aspects of plant design and operation, including safety and hazard assessments, process design and analysis, modeling, control engineering, chemical reaction engineering, nuclear engineering, biological engineering, construction specification, and operating instructions.

Chemical engineers typically hold a degree in Chemical Engineering or Process Engineering. Practising engineers may have professional certification and be accredited members of a professional body. Such bodies include the Institution of Chemical Engineers (IChemE) or the American Institute of Chemical Engineers (AIChE). A degree in chemical engineering is directly linked with all of the other engineering disciplines, to various extents.

Etymology

A 1996 British Journal for the History of Science article cites James F. Donnelly for mentioning an 1839 reference to chemical engineering in relation to the production of sulfuric acid. In the same paper however, George E. Davis, an English consultant, was credited for having coined the term. Davis also tried to found a Society of Chemical Engineering, but instead it was named the Society of Chemical Industry (1881), with Davis as its first Secretary. The History of Science in United States: An Encyclopedia puts the use of the term around 1890. « Chemical engineering », describing the use of mechanical equipment in the chemical industry, became common vocabulary in England after 1850. By 1910, the profession, « chemical engineer, » was already in common use in Britain and the United States.

Chemical process

In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of some sort. In an « engineering » sense, a chemical process is a method intended to be used in manufacturing or on an industrial scale (see Industrial process) to change the composition of chemical(s) or material(s), usually using technology similar or related to that used in chemical plants or the chemical industry.

Neither of these definitions are exact in the sense that one can always tell definitively what is a chemical process and what is not; they are practical definitions. There is also significant overlap in these two definition variations. Because of the inexactness of the definition, chemists and other scientists use the term « chemical process » only in a general sense or in the engineering sense. However, in the « process (engineering) » sense, the term « chemical process » is used extensively. The rest of the article will cover the engineering type of chemical processes.

Although this type of chemical process may sometimes involve only one step, often multiple steps, referred to as unit operations, are involved. In a plant, each of the unit operations commonly occur in individual vessels or sections of the plant called units. Often, one or more chemical reactions are involved, but other ways of changing chemical (or material) composition may be used, such as mixing or separation processes. The process steps may be sequential in time or sequential in space along a stream of flowing or moving material; see Chemical plant. For a given amount of a feed (input) material or product (output) material, an expected amount of material can be determined at key steps in the process from empirical data and material balance calculations. These amounts can be scaled up or down to suit the desired capacity or operation of a particular chemical plant built for such a process. More than one chemical plant may use the same chemical process, each plant perhaps at differently scaled capacities. Chemical processes like distillation and crystallization go back to alchemy in Alexandria, Egypt.

Such chemical processes can be illustrated generally as block flow diagrams or in more detail as process flow diagrams. Block flow diagrams show the units as blocks and the streams flowing between them as connecting lines with arrowheads to show direction of flow.

In addition to chemical plants for producing chemicals, chemical processes with similar technology and equipment are also used in oil refining and other refineries, natural gas processing, polymer and pharmaceutical manufacturing, food processing, and water and wastewater treatment.

Unit processing in chemical process

Unit processing is the basic processing in chemical engineering. Together with unit operations it forms the main principle of the varied chemical industries. Each genre of unit processing follows the same chemical law much as each genre of unit operations follows the same physical law.

Chemical engineering unit processing consists of the following important processes:

• Oxidation
• Reduction
• Hydrogenation
• Dehydrogenation
• Hydrolysis
• Hydration
• Dehydration
• Halogenation
• Nitrification
• Sulfonation
• Ammoniation
• Alkaline fusion
• Alkylation
• Dealkylation
• Esterification
• Polymerization
• Polycondensation
• Catalysis

Unit operation

In chemical engineering and related fields, a unit operation is a basic step in a process. Unit operations involve a physical change or chemical transformation such as separation, crystallization, evaporation, filtration, polymerization, isomerization, and other reactions. For example, in milk processing, homogenization, pasteurization, and packaging are each unit operations which are connected to create the overall process. A process may require many unit operations to obtain the desired product from the starting materials, or feedstocks.

Historically, the different chemical industries were regarded as different industrial processes and with different principles. Arthur Dehon Little propounded the concept of « unit operations » to explain industrial chemistry processes in 1916. In 1923, William H. Walker, Warren K. Lewis and William H. McAdams wrote the book The Principles of Chemical Engineering and explained that the variety of chemical industries have processes which follow the same physical laws. They summed up these similar processes into unit operations. Each unit operation follows the same physical laws and may be used in all relevant chemical industries. For instance, the same engineering is required to design a mixer for either napalm or porridge, even if the use, market or manufacturers are very different. The unit operations form the fundamental principles of chemical engineering.

Chemical engineering unit operations consist of five classes:

1. Fluid flow processes, including fluids transportation, filtration, and solids fluidization.
2. Heat transfer processes, including evaporation and heat exchange.
3. Mass transfer processes, including gas absorption, distillation, extraction, adsorption, and drying.
4. Thermodynamic processes, including gas liquefaction, and refrigeration.
5. Mechanical processes, including solids transportation, crushing and pulverization, and screening and sieving.

Chemical engineering unit operations also fall in the following categories which involve elements from more than one class:

• Combination (mixing)
• Separation (distillation, crystallization)
• Reaction (chemical reaction)

Furthermore, there are some unit operations which combine even these categories, such as reactive distillation and stirred tank reactors. A « pure » unit operation is a physical transport process, while a mixed chemical/physical process requires modeling both the physical transport, such as diffusion, and the chemical reaction. This is usually necessary for designing catalytic reactions, and is considered a separate discipline, termed chemical reaction engineering.

Chemical engineering unit operations and chemical engineering unit processing form the main principles of all kinds of chemical industries and are the foundation of designs of chemical plants, factories, and equipment used.

In general, unit operations are designed by writing down the balances for the transported quantity for each elementary component (which may be infinitesimal) in the form of equations, and solving the equations for the design parameters, then selecting an optimal solution out of the several possible and then designing the physical equipment. For instance, distillation in a plate column is analyzed by writing down the mass balances for each plate, wherein the known vapor-liquid equilibrium and efficiency, drip out and drip in comprise the total mass flows, with a sub-flow for each component. Combining a stack of these gives the system of equations for the whole column. There is a range of solutions, because a higher reflux ratio enables fewer plates, and vice versa. The engineer must then find the optimal solution with respect to acceptable volume holdup, column height and cost of construction.

Entre opération unitaire et procédé unitaire

Unit operation

Arthur Dehon Little is credited with the approach chemical engineers to this day take: process-oriented rather than product-oriented analysis and design. The concept of unit operations was developed to emphasize the underlying similarity among seemingly different chemical productions. For example, the principles are the same whether one is concerned about separating alcohol from water in a fermenter, or separating gasoline from diesel in a refinery, as long as the basis of separation is generation of a vapor of a different composition from the liquid. Therefore, such separation processes can be studied together as a unit operation, in this case called distillation.

Unit processes

In the early part of the last century, a parallel concept called Unit Processes was used to classify reactive processes. Thus oxidations, reductions, alkylations, etc. formed separate unit processes and were studied as such. This was natural considering the close affinity of chemical engineering to industrial chemistry at its inception. Gradually however, the subject of chemical reaction engineering has largely replaced the unit process concept. This subject looks at the entire body of chemical reactions as having a personality of its own, independent of the particular chemical species or chemical bonds involved. The latter does contribute to this personality in no small measure, but to design and operate chemical reactors, a knowledge of characteristics such as rate behaviour, thermodynamics, single or multiphase nature, etc. are more important. The emergence of chemical reaction engineering as a discipline signaled the severance of the umbilical cord connecting chemical engineering to industrial chemistry and cemented the unique character of the discipline.

History of chemical engineering

Chemical engineering is a discipline that was developed out of those practicing « industrial chemistry » in the late 19th century. Before the Industrial Revolution (18th century), industrial chemicals and other consumer products such as soap were mainly produced through batch processing. Batch processing is labour-intensive and individuals mix predetermined amounts of ingredients in a vessel, heat, cool or pressurize the mixture for a predetermined length of time. The product may then be isolated, purified and tested to achieve a saleable product. Batch processes are still performed today on higher value products, such as pharmaceutical intermediates, speciality and formulated products such as perfumes and paints, or in food manufacture such as pure maple syrups, where a profit can still be made despite batch methods being slower and inefficient in terms of labour and equipment usage. Due to the application of Chemical Engineering techniques during manufacturing process development, larger volume chemicals are now produced through a continuous « assembly line » chemical processes. The Industrial Revolution was when a shift from batch to more continuous processing began to occur. Today commodity chemicals and petrochemicals are predominantly made using continuous manufacturing processes whereas speciality chemicals, fine chemicals and pharmaceuticals are made using batch processes.

Chemical engineering emerged upon the development of unit operations, a fundamental concept of the discipline of chemical engineering. Most authors agree that Davis invented the concept of unit operations if not substantially developed it. He gave a series of lectures on unit operations at the Manchester Technical School (later part of the University of Manchester) in 1887, considered to be one of the earliest such about chemical engineering. Three years before Davis’ lectures, Henry Edward Armstrong taught a degree course in chemical engineering at the City and Guilds of London Institute. Armstrong’s course failed simply because its graduates were not especially attractive to employers. Employers of the time would have rather hired chemists and mechanical engineers. Courses in chemical engineering offered by Massachusetts Institute of Technology (MIT) in the United States, Owens College in Manchester, England, and University College London suffered under similar circumstances.

Starting from 1888, Lewis M. Norton taught at MIT the first chemical engineering course in the United States. Norton’s course was contemporaneous and essentially similar to Armstrong’s course. Both courses, however, simply merged chemistry and engineering subjects along with product design. « Its practitioners had difficulty convincing engineers that they were engineers and chemists that they were not simply chemists. » Unit operations was introduced into the course by William Hultz Walker in 1905. By the early 1920s, unit operations became an important aspect of chemical engineering at MIT and other US universities, as well as at Imperial College London. The American Institute of Chemical Engineers (AIChE), established in 1908, played a key role in making chemical engineering considered an independent science, and unit operations central to chemical engineering. For instance, it defined chemical engineering to be a « science of itself, the basis of which is … unit operations » in a 1922 report; and with which principle, it had published a list of academic institutions which offered « satisfactory » chemical engineering courses. Meanwhile, promoting chemical engineering as a distinct science in Britain led to the establishment of the Institution of Chemical Engineers (IChemE) in 1922. IChemE likewise helped make unit operations considered essential to the discipline.

Origin

The Industrial Revolution led to an unprecedented escalation in demand, both with regard to quantity and quality, for bulk chemicals such as soda ash. This meant two things: one, the size of the activity and the efficiency of operation had to be enlarged, and two, serious alternatives to batch processing, such as continuous operation, had to be examined.

The first chemical engineer

Industrial chemistry was being practiced in the 1800s, and its study at British universities began with the publication by Friedrich Ludwig Knapp, Edmund Ronalds and Thomas Richardson of the important book Chemical Technology in 1848. By the 1880s the engineering elements required to control chemical processes were being recognized as a distinct professional activity. Chemical engineering was first established as a profession in the United Kingdom after the first chemical engineering course was given at the University of Manchester in 1887 by George E. Davis in the form of twelve lectures covering various aspects of industrial chemical practice. As a consequence George E. Davis is regarded as the world’s first chemical engineer. Today, chemical engineering is a highly regarded profession. Chemical engineers with experience can become licensed Professional Engineers in the United States, aided by the National Society of Professional Engineers, or gain « Chartered » chemical-engineer status through the UK-based Institution of Chemical Engineers.

George E. Davis

George Edward Davis (1850–1907) is regarded as the founding father of the discipline of chemical engineering.

Life

Davis was born at Eton on 27 July 1850, the eldest son of George Davis, a bookseller. At the age of fourteen he was apprenticed to a local bookbinder but he abandoned this trade after two years to pursue his interest in chemistry. Davis studied at the Slough Mechanics Institute while working at the local gas works, and then spent a year studying at the Royal School of Mines in London (now part of Imperial College, London) before leaving to work in the chemical industry around Manchester, which at the time was the main centre of the chemical industry in the UK.

Davis worked as a chemist at Brearley and Sons for three years. He also worked as an inspector for the Alkali Act of 1863, a very early piece of environmental legislation that required soda manufacturers to reduce the amount of gaseous hydrochloric acid released to the atmosphere from their factories. In 1872 he was engaged as manager at the Lichfield Chemical Company in Staffordshire. In this job his capacity for innovation flourished. His works included what was at the time the tallest chimney in the UK, with a height of more than 200 feet (61 m).

He married Laura Frances Miller on 10 December 1878, and they had at least one son. He worked as a consultant to the chemical industry jointly with his brother Alfred, founded the Chemical Trade Journal and had 67 patents granted, as well as publishing scientific papers.

Davis was also instrumental in the formation of the Society of Chemical Industry (1881), which he had wanted to name the Society of Chemical Engineering, and was its first Secretary. He was also interested in microscopy, founding the journal Northern Microscopist in 1881, and publishing a textbook on the subject, Practical Microscopy. He died in West Dulwich, on 20 April 1907.

Contribution to chemical engineering

Davis identified broad features in common to all chemical factories and wrote the influential A Handbook of Chemical Engineering. He also published a famous lecture series of 12 lectures, given in 1888 at Manchester Technical School (which became University of Manchester Institute of Science and Technology (UMIST)). These lectures defined chemical engineering as a discipline.

His lectures were criticized for being common place know-how since it was designed around operating practices used by British chemical industries. At this time, however, in the United States, this information helped initiate new thinking in the chemical industry, as well as spark chemical engineering degree programmes at several universities in the US.

Recognition

In the 1st floor foyer of Jackson’s Mill, the building that houses the School of Chemical Engineering and Analytical Science, University of Manchester, there is a display and memorial to Davis. The George E. Davis Medal of the Institution of Chemical Engineers is named in his honour.

New concepts and innovations

In 1940s, it became clear that unit operations alone were insufficient in developing chemical reactors. While the predominance of unit operations in chemical engineering courses in Britain and the United States continued until the 1960s, transport phenomena started to experience greater focus.  Along with other novel concepts, such as process systems engineering (PSE), a « second paradigm » was defined. Transport phenomena gave an analytical approach to chemical engineering  while PSE focused on its synthetic elements, such as control system and process design. Developments in chemical engineering before and after World War II were mainly incited by the petrochemical industry, however, advances in other fields were made as well. Advancements in biochemical engineering in the 1940s, for example, found application in the pharmaceutical industry, and allowed for the mass production of various antibiotics, including penicillin and streptomycin. Meanwhile, progress in polymer science in the 1950s paved way for the « age of plastics »

Safety and hazard developments

Concerns regarding the safety and environmental impact of large-scale chemical manufacturing facilities were also raised during this period. Silent Spring, published in 1962, alerted its readers to the harmful effects of DDT, a potent insecticide. The 1974 Flixborough disaster in the United Kingdom resulted in 28 deaths, as well as damage to a chemical plant and three nearby villages. The 1984 Bhopal disaster in India resulted in almost 4,000 deaths. These incidents, along with other incidents, affected the reputation of the trade as industrial safety and environmental protection were given more focus. In response, the IChemE required safety to be part of every degree course that it accredited after 1982. By the 1970s, legislation and monitoring agencies were instituted in various countries, such as France, Germany, and the United States.

Recent progress

Advancements in computer science found applications designing and managing plants, simplifying calculations and drawings that previously had to be done manually. The completion of the Human Genome Project is also seen as a major development, not only advancing chemical engineering but genetic engineering and genomics as well. Chemical engineering principles were used to produce DNA sequences in large quantities.

Concepts

Chemical engineering involves the application of several principles. Key concepts are presented below.

Plant design and construction

Chemical engineering design concerns the creation of plans, specification, and economic analyses for pilot plants, new plants or plant modifications. Design engineers often work in a consulting role, designing plants to meet clients’ needs. Design is limited by a number of factors, including funding, government regulations and safety standards. These constraints dictate a plant’s choice of process, materials and equipment.

Plant construction is coordinated by project engineers and project managers depending on the size of the investment. A chemical engineer may do the job of project engineer full-time or part of the time, which requires additional training and job skills or act as a consultant to the project group. In the USA the education of chemical engineering graduates from the Baccalaureate programs accredited by ABET do not usually stress project engineering education, which can be obtained by specialized training, as electives, or from graduate programs. Project engineering jobs are some of the largest employers for chemical engineers.

Process design and analysis

A unit operation is a physical step in an individual chemical engineering process. Unit operations (such as crystallization, filtration, drying and evaporation) are used to prepare reactants, purifying and separating its products, recycling unspent reactants, and controlling energy transfer in reactors. On the other hand, a unit process is the chemical equivalent of a unit operation. Along with unit operations, unit processes constitute a process operation. Unit processes (such as nitration and oxidation) involve the conversion of material by biochemical, thermochemical and other means. Chemical engineers responsible for these are called process engineers.

Process design requires the definition of equipment types and sizes as well as how they are connected together and the materials of construction. Details are often printed on a Process Flow Diagram which is used to control the capacity and reliability of a new or modified chemical factory.

Education for chemical engineers in the first college degree 3 or 4 years of study stresses the principles and practices of process design. The same skills are used in existing chemical plants to evaluate the efficiency and make recommendations for improvements.

Transport phenomena

Modeling and analysis of transport phenomena is essential for many industrial applications. Transport phenomena involve fluid dynamics, heat transfer and mass transfer, which are governed mainly by momentum transfer, energy transfer and transport of chemical species, respectively. Models often involve separate considerations for macroscopic, microscopic and molecular level phenomena. Modeling of transport phenomena, therefore, requires an understanding of applied mathematics.

Domaines d’application

Les méthodes du génie des procédés s’appliquent à toutes les industries transformant la matière.

Le génie chimique ou génie des procédés s’intègre dans les secteurs suivants :

• laboratoire de contrôle qualité ;
• industries chimique et para-chimique ;
• industrie pharmaceutique ;
• industries pétrolière et pétrochimique ;
• ingénierie et industries d’équipement ;
• environnement : traitement de l’eau, de l’air, des déchets ;
• industrie agroalimentaire et bio-industries ;
• industries diverses : métallurgie, textile, caoutchouc, verre, papier, etc.

Applications and practice

Chemical engineers « develop economic ways of using materials and energy ». Chemical engineers use chemistry and engineering to turn raw materials into usable products, such as medicine, petrochemicals and plastics on a large-scale, industrial setting. They are also involved in waste management and research. Both applied and research facets could make extensive use of computers.

Chemical engineers may be involved in industry or university research where they are tasked with designing and performing experiments to create better and safer methods for production, pollution control, and resource conservation. They may be involved in designing and constructing plants as a project engineer. Chemical engineers serving as project engineers use their knowledge in selecting optimal production methods and plant equipment to minimize costs and maximize safety and profitability. After plant construction, chemical engineering project managers may be involved in equipment upgrades, process changes, troubleshooting, and daily operations in either full-time or consulting roles.

History of chemical engineering

Arthur D. Little, William H. Walker, and Warren K. Lewis

In the late 19th century Little, Walker, and Lewis worked to define chemical engineering as a distinct field with a special training method.

The notion of a new kind of engineer―a chemical engineer―who understood both chemical processes and mechanical equipment was broached in England around 1880.

The idea first took firm root, however, in the United States in the 1890s. Arthur D. Little, William H. Walker, and Warren K. Lewis were among the leaders of the movement to create the new profession of chemical engineering.

Chemical Engineering as a Profession

According to the British engineer George E. Davis, the ideal chemical engineer could move from industry to industry, mixing and matching the various operations that the American Arthur Little (1863–1935) was later to call “unit operations.” Little first used this term in a 1915 report to the president of the Massachusetts Institute of Technology (MIT), where the curriculum in “chemical engineering” dated from 1888. The first degrees in this field in the United States were given at MIT in 1891, although the content of the original courses still centered on industrial chemistry and mechanical engineering, without the characteristic unit-operations laboratory. William Walker (1869–1934), Warren Lewis (1882–1975), and Little were among the leaders who defined chemical engineering as a separate profession with a distinct approach and training method.

Arthur Dehon Little.

Arthur D. Little, Inc., and the American Chemical Industry

A native of Boston, Little majored in chemistry at MIT before the advent of chemical engineering and was the editor of the college newspaper, The Tech—an experience that prepared him for his role as a spokesperson for chemical-engineering education, industrial research, and the American chemical industry. His first jobs made him an expert in the new sulfite process for making paper, and in 1886 he and a coworker, Roger B. Griffin, set up a consulting company whose successor, Arthur D. Little, Inc., prospered as an independent company for more than a century. (In 2002 it became part of the Paris-based consulting firm Altran.) Seven years after Little and Griffin founded their company, Griffin died tragically in a laboratory explosion. Little continued as a consultant, becoming involved in two new synthetics—cellulose nitrate and cellulose acetate—that were being used for photographic film and woven fabrics. The reluctance of American financiers to undertake ventures in this new technology—opportunities that were instead seized by Europeans starting up plants in the United States—prompted Little to mount a writing and speaking campaign directed at financial, political, and educational leaders to encourage the nascent American chemical industry. From an early date Little also preached against heedless industrial practices, referring ominously to “the handwriting on the wall” for a society that would destroy its own environment. 

William H. Walker with slide rule at the ready.

Little and Walker: A Partnership

In 1900 Little formed a new partnership with William Walker, a young MIT chemistry instructor who had graduated from Pennsylvania State University with a bachelor’s degree in chemistry and who held a doctorate in organic chemistry from the University of Göttingen in Germany. Walker was soon recalled to MIT to reform the chemical-engineering curriculum—with Little in the background gaining approval and funds for various initiatives to bring industry and education closer together. In 1908 MIT’s Research Laboratory of Applied Chemistry began operations. Here chemical-engineering students worked on real industrial problems presented by various chemical companies, which also supplied fellowships.

Lewis Joins Chemical Engineering at MIT

In 1908 Warren Lewis, a young graduate of MIT’s chemical-engineering program with a PhD in organic chemistry from the University of Breslau (then part of Germany and now the University of Wrocław in Poland), joined the teaching staff at MIT. He contributed a great deal to the program with his ability to view engineering problems theoretically and mathematically and with his memorable teaching style, which was sometimes described as bombastic but nonetheless endeared him to students. In 1916 three plant-based stations of the School of Chemical Engineering Practice were inaugurated, thus enabling students to gain more hands-on experience by spending eight weeks at one of the stations under the supervision of an MIT faculty member. Meanwhile, under Lewis’s guidance, teaching in the fundamental unit-operations course had become highly quantitative. One result of this course, The Principles of Chemical Engineering (1923) written by Walker, Lewis, and William H. McAdams, became the standard text for chemical-engineering instruction for decades.

Warren K. Lewis teaching at MIT’s School of Chemical Engineering Practice at the Bayway Refinery of Standard Oil Company of New Jersey.

Later Achievements and Recognition

Shortly after publication of the book Walker returned to consulting. From his faculty position Lewis also maintained close connections with industry, consulting most frequently for Standard Oil Company of New Jersey (now ExxonMobil). His most famous industrial contribution—in collaboration with his colleague Edwin R. Gilliland—was fluidized-bed catalytic cracking of petroleum, which solved many of the problems posed by the catalytic cracking process developed by Eugene Houdry and played a large part in supplying the vast quantities of gasoline needed during World War II.

In 1947 Lewis became the first chemical engineer to receive the Priestley Medal, the highest honor conferred by the American Chemical Society; he was also an elected member of the National Academy of Engineering. For his contributions to the growth of American chemical industry, Little was awarded the prestigious Perkin Medal in 1931 by the Society of Chemical Industry, while Lewis received it in 1936. 

The information contained in this biography was last updated on December 11, 2017.

The First Century of Chemical Engineering

In 2008 the American Institute of Chemical Engineers celebrated its centennial. Its founding furthered the profession of chemical engineering and represented the beginning of American technological dominance in the 20th century. By Nicholas A. Peppas | June 2, 2016

Arthur Dehon Little. Science History Institute

The American Institute of Chemical Engineers (AIChE) was established by a committee of chemists and engineers in 1908 during a period of industrial renaissance in the United States. At the turn of the last century the major world powers were anticipating the great need for engineering expertise both at home and throughout their empires; to be competitive in the world markets required major attention to engineering and technology. A telling sign of this competition was the appearance of several technologically sophisticated and nationalistic super ocean liners launched between 1900 and 1912: the Mauretania, the Deutschland, the France, and especially the Imperator, whose impressive structure, speed, and opulence represented a momentary display of German superiority. The founding of AIChE in 1908 was important not only for the professionalization of chemical engineering, but also because it represented the beginning of American technological dominance in the world stage of the 20th century. On 12 June 2008 AIChE celebrated its centennial in Philadelphia, the site of its original meeting 100 years ago.

The Industrial Chemical Lab at Massachusetts Institute of Technology, 1893. MIT Museum

The European Crucible

The chemical industry had a central position in the changing industrial world of the late 19th century. This industry did not hatch fully grown; it was based on nearly a century’s worth of scientific advances in the universities—particularly German universities.

In the beginning of the 19th century, scientific conditions were such that the study of chemistry was flourishing in Germany. Prominent among all scientists, Justus von Liebig (1803–1873) may be considered a major force in 19th-century chemistry, not only because of his seminal research achievements but also because of his great gift as an educator. In 1825 Liebig established a small chemistry laboratory at the University of Giessen, a town 35 miles north of Frankfurt, Germany. Over the next 30 years a large number of famous scientists would be educated there, including August Kekulé, August Wilhelm Hofmann, Adolphe Wurtz, and Charles Gerhardt. By the second quarter of the 19th century, three major chemistry laboratories at the universities of Giessen, Göttingen, and Heidelberg were producing a number of outstanding organic and physical chemists. All of them did imaginative research that led to new production methods of important chemicals and nourished the German, European, and—indirectly—American industry. Students educated in these laboratories would in turn establish laboratories elsewhere, including the United States.

What set Liebig and his students apart from other university chemists of the time was an interest in applying their fundamental discoveries to the development of specific chemical processes and products. Hoffman’s aniline dye process is only one of many such processes developed between 1840 and 1880 in Germany.

In 1848 the political revolution that had started in France swept eastward across the Rhine, overthrowing established authority in Germany and giving central Europe a taste of liberal reform. The Industrial Revolution, made possible by chemistry, proved immensely profitable on the one hand, but on the other it also created new factory environments with deplorable working conditions. One result of the political changes in 1848 was an attempt to revise industrial processes with an emphasis, though primitive, on safer and more efficient methods. These were the circumstances from which the field of chemical engineering would emerge in the mid-19th century.

Creating a Curriculum

Despite the developments in German universities and industry, education in chemistry and chemical engineering had not been formalized. Students obtained at best superficial knowledge about the new industrial chemical processes in their chemistry courses. The operation of distillation columns, filtration units, and the like was taught in so-called technical schools, not in universities. The Technical University of Braunschweig, for instance, soon offered “industrial” courses, but in the eyes of Liebig’s academic descendants at Göttingen, Heidelberg, and Berlin, it was not to be considered a university.

By the end of the 19th century, competition among Great Britain, Germany, and the United States for industrial chemicals had become rather fierce, and chemical engineering expertise was in high demand. The first course in chemical engineering was offered by an unknown industrial prospector from Manchester, England, named George E. Davis, who decided to transfer his vast knowledge from years of inspecting chemical plants in the industrial regions of England to the classroom. In fall 1887 he gave a series of 12 lectures that were later published in Chemical Trade Journal. The next year Lewis M. Norton (1855–1893) of the chemistry department of the Massachusetts Institute of Technology (MIT) offered a new course in chemical engineering. The course material was taken predominantly from Norton’s notes on industrial practice in Germany, which at that time had probably the most advanced chemical process industry in the world.

When Norton died in 1893, Frank H. Thorpe (1864– 1932), an MIT graduate who had earned a doctorate from the University of Heidelberg that same year, took responsibility for Norton’s course. Five years later he published what may be considered the first textbook on chemical engineering, entitled Outlines of Industrial Chemistry. This textbook made mention of the chemical treatment of biological by-products, a very faint indication of early biotechnology processes.

Although Norton and Thorpe pioneered the teaching of chemical engineering in the United States, it was Arthur A. Noyes (1866–1936) and later William H. Walker (1869–1934) who helped bring to the discipline the respect it would eventually enjoy within the engineering curriculum. Noyes established the Research Laboratory of Physical Chemistry at MIT in 1903 before making his mark in 1913 by transforming what was then Throop College into the California Institute of Technology. Walker, who had received his doctorate in 1892 at the University of Göttingen with future Nobel laureate Otto Wallach, was hired as an instructor at MIT in 1902. Under Walker’s leadership, MIT’s Division of Applied Chemistry (as it was then known) flourished, and the establishment of its Research Laboratory of Applied Chemistry followed in 1908. In his institution-building work Walker was assisted by Warren K. Lewis (1882–1975), for whom the prestigious AIChE teaching and education award is named. He left a deep impact not only through his series of industrial consultancies and attempts at profession building, but also through his emphasis on practical teaching.

In England, during the same period, Davis proceeded with the publication of his Handbook of Chemical Engineering (1901), which was revised and published in a second edition of over 1,000 pages in 1904. Davis’s textbook was particularly important because it introduced the notion of “unit operations,” although the term itself would not be coined until 1915 by Arthur D. Little at MIT. As developed by the two men, “unit operations” referred to the idea that all chemical processes can be analyzed by dividing them into distinct operations, such as distillation, extraction, filtration, and crystallization, all of which are governed by certain principles. More than anything, however, Davis was responsible for coining the term chemical engineering to describe this new engineering area that addressed problems of the chemical industry.

In the United States, MIT is considered the first university to have offered, in 1888, a four-year curriculum in chemical engineering, in 1888. Other universities soon followed MIT’s example: the University of Pennsylvania (1894), Tulane University (1894), the University of Michigan (1898), and Tufts University (1898). Each of these four-year programs in chemical engineering were housed within the chemistry department.

The Institution of a Profession

In this climate of international competition and academic excitement the young field of chemical engineering found the right ground to thrive in. In 1903 a specialized publication appeared. The Chemical Engineer was not exactly a scientific journal, but it included practical articles written by practicing industrial chemists and engineers, including William Walker. By 1905 this magazine had a circulation of more than 1,600, including about 570 chemical engineers.

By 1904 tensions were bubbling up among members at American Chemical Society (ACS) meetings about the relationship between chemistry and chemical engineering. At that year’s meeting Hugo Schweitzer, a prominent New York industrial chemist, declared himself « absolutely against the introduction of chemical engineering in the education of chemists. ”In the same meeting M. T. Bogert agreed with Schweitzer, saying that progress in “technical chemistry” was best achieved in research laboratories by researchers without engineering training. But the engineers found a defender in Milton C. Whitaker, a professor of chemistry at Columbia University, who argued that a chemist was “generally not the man who is capable of transmitting from a laboratory to a factory the ideas which he has developed ”because he lacks education “in the engineering branches.”

The controversy soon spurred action. Three years later a group of 12 chemists and engineers met at the Chalfonte Hotel in Atlantic City to discuss the future of their profession. At the end of their discussion they formed the so-called Committee of Six to explore the “possibility of forming a chemical engineering organization.” The Committee of Six represented the core of what would become AIChE’s leadership, which included Walker as well as three men who would go on to become presidents of the organization: Arthur D. Little (1919), Charles F. McKenna (1910), and John C. Olsen (1931). Discussions continued for almost six months after the meeting, but it was finally decided that an organizational meeting was the next step.

The Committee of Six, joined by 15 other chemists and chemical engineers, held its next meeting in January 1908 at the Belmont Hotel in New York. Once again Bogert, by this time president of the ACS, raised the objection that his organization already served the needs of practicing industrial chemists. Nevertheless, the Committee of Six stood firm and decided to form a new organization dedicated to chemical engineering. On 22 June 1908 the first meeting of the AIChE convened at the Engineer’s Club of Philadelphia. According to minutes recorded by William Meade, “enthusiasm ran high” among the 40 men in attendance.

As originally envisioned, one of the primary goals of AIChE was to raise the professional status of the 500 or so chemical engineers then working in American factories and chemical manufacturing plants. Partly as a way to placate the ACS and partly in an attempt to make membership exclusive—and therefore prestigious—the AIChE initially adopted strict membership requirements: members had to be at least 30 years old, be currently engaged in “applied” chemistry, and have either 5 or 10 years of industrial experience, depending on whether the applicant held a science degree. These requirements kept membership small (well under 1,000) through the first two decades of the organization’s existence.

In those days the training of chemical engineers was a subject of much debate in AIChE meetings. Whitaker, an influential professor of chemical engineering at Columbia University and an early president of AIChE (1914), expressed his views on the training of chemical engineers as follows: “The chemical engineer works in the organization, operation, and management of existing or proposed processes with a view to building up a successful manufacturing industry . . . His fundamental training in chemistry, physics, mathematics, etc., must be thorough and must be combined with a natural engineering inclination and an acquired knowledge of engineering methods and appliances.” He continued by giving a description of the types of courses that should be taught, which he classified as courses for “fundamental training” (chemistry, physics, mathematics), “associated training” (electrical, mechanical, civil, and general engineering, and business economics), and “supplementary training” (laboratory and administration courses). For Whitaker it was important that a distinction be made between the education of a chemical engineer and that of an industrial chemist. The chemical engineer would study both chemical processes and unit operations, while the industrial chemist traditionally learned specific procedures for producing bulk quantities of feedstock chemicals. His views affected his graduate students, prominent among whom was Eugene E. Leslie, who would later teach at the University of Michigan.

Over the course of the 20th century, chemical engineering gradually developed a specific disciplinary identity, focusing first on unit operations, then adding applied thermodynamics, chemical-reaction engineering, applied mathematics, and computer science. By the mid-1970s, researchers realized that chemical engineers could contribute significantly to areas outside of the core of classical chemical engineering, including interdisciplinary areas such as the biochemical and biomedical sciences and materials science. Today chemical engineers are leading the way in sustainability, nanotechnology, high-performance materials, and electronics manufacturing.

The establishment of AIChE in 1908 gave shape to the dreams of the “converted chemists” who were calling themselves chemical engineers in the face of opposition from employers as well as professional colleagues. After a century of growth AIChE is unquestionably the world’s leading organization for chemical engineers, with more than 40,000 members in more than 90 countries and more than 100 local sections. Now, in the beginning of the 21st century, chemical engineers’ contributions remain critical not only to the global economy, but also to modern life.

George E. Davis

Working in the late 19th century, Davis, an Englishman, was often credited with being the father of chemical engineering by members of subsequent generations of chemical engineers. His Handbook of Chemical Engineering was the first of its kind.

In England in the 1880s George E. Davis’s ideas about engineering promoted a new scientific field, one that encompassed both chemical processes and mechanical equipment.

But the concept was not fully embraced until the 1890s, by engineers in the United States. Chemical engineering subsequently became an established field of study.

Early Pioneer in Chemical Engineering

The eldest son of a bookseller, Davis (1850–1906) studied at the Slough Mechanics Institute and the Royal School of Mines in London (now part of Imperial College, London) and then headed north to work in the chemical industry around Manchester. Before he embarked on a career as a consulting engineer, he held various positions—one as an inspector for the Alkali Act of 1863, a very early piece of environmental legislation that required soda manufacturers to reduce the amount of hydrochloric acid gas vented into the atmosphere from their factories. Davis was also a moving spirit behind the formation of the Society of Chemical Industry (1881), which he had wanted to name the Society of Chemical Engineering.

Davis’s Handbook of Chemical Engineering

In 1887 Davis gave a series of 12 lectures at the Manchester School of Technology (now part of the University of Manchester), which formed the basis of his two-volume Handbook of Chemical Engineering (1901; revised 1904), the first of its kind. There were already industrial chemistry books written for each chemical industry—for example, alkali manufacture, acid production, brewing, and dyeing—and even a few overviews, but Davis was unique in organizing his text by the basic operations common to many industries—transporting solids, liquids, and gases; distillation; crystallization; and evaporation, to name a few—and heavily illustrating these with the plant machinery then available for purchase. Moreover, he was generous in providing real-life examples of the practices and problems of the chemical plant. During his busy consulting career Davis only taught the one lecture series, and so his handbook had to play the role of creating disciples. Evidently it did in the case of American professors like the Massachusetts Institute of Technology’s William H. Walker and Warren K. Lewis.

The information contained in this biography was last updated on December 4, 2017.