History of the chemical engineering technologies

1. Dr. Yehia El Shazly

2. Rules of Engagement
 No talking.
 In case of discussions , no shouting is
allowed, but civilized discussions.
 Strictly no mobile phone; The OWNER will
SEVERELY PUNISHED.
 No food is allowed (including chewing
gums or mastication).
 Coming late.

3.  What is chemical engineering?
 How, and why, did chemical engineering develop?
 What obstacles did the profession face and
overcome?
 What contributions have chemical engineers
made?
 How has the profession grown and changed over
the last Century?

4. What is a Chemical Engineer?
 a) An Engineer who manufactures
chemicals,
 b) A Chemist who works in a factory, or
 c) A glorified Plumber?
 d) None of the above.

5. In fact, the term "chemical engineer" is
not even intended to describe the type of
work a chemical engineer performs.
Instead it is meant to reveal what
makes the field different from the
other branches of engineering.

6.  All engineers employ mathematics,
physics, and the engineering art to
overcome technical problems in a safe and
economical fashion.
 Yet, it is the chemical engineer alone that
draws upon the vast and powerful science
of chemistry to solve a wide range of
problems.

7. The breadth of scientific and technical knowledge
inherent in the profession has caused some to
describe the chemical engineer as the
"universal engineer“.
Yes, you are hearing me correctly; despite a title
that suggests a profession composed of narrow
specialists, chemical engineers are actually
extremely versatile and able to handle a wide
range of technical problems.

9. Process Design

10. A chemist found that if you mix two reactant at
elevated temperature, he obtains a product more
valuable.
 Is the process economically feasible.
 What should the reaction be carried out in?
 Where should the reactants be obtained?
 In what proportions should they be fed to the
reactor?
 Separation of products from the effluent.
 Transport of streams.
 Pilot plant construction.

11.  What possibly can go wrong in the
process.
 Dealing with waste products.
 Process automation and control.
 Cost, depreciation and price of products.
 Plant startup.
 Product quality control and modifications.
 Hazards analysis and accidents
investigations.
 Product alteration.

12. Electric Power Generation

14.  Turbine: steam – water – wind – hot
gases.
 Steam: boiler designed to burn a fuel oil
or natural gas.
 How much does the oil cost now?
 Future reserve and supplies and expect
future price.
 Alternative sources: coal.
 Coal current price/reserve/ future price?
 Redesigning the plant and the boiler.

15.  Stack gases from the coal contains
pollutants ( CO, SO2, ash, tars) +
hazardous trace components (lead,
arsenic).
 Expected emissions rates of these
substance?
 Laws regulating these emissions.
 Resultant health results in the plant.
 Emission reduction: filtration, centrifugal
separation, wet scrubbing, electrostatic
precipitation.

16.  By products in the stack gas – sulphur
(can it be converted to marketable form).
 Ash collected in the furnace .
 Is it more economical to pretreat the coal
to remove the potential pollutants?
(pulverizing the coal, gasifying the coal)
 How much air should be fed to burn the
required amount of fuel? Should it be
preheated to increase the efficiency of the
steam generation operation?

17.  Furnace design: temperatures and
pressures? Material of construction? Inlet
and outlet?
 Steam tube embedded in furnace walls or
running through the combustion zone?
 Control / hazards / safety and precautions.
 Economical analysis of the process.

18. Kidney Failure

19. Dialysis

20. Hemodialysis

21. Hemodialysis

22.  DIALYSIS transfer of solute (dissolved
solids) across a semipermeable
membrane.
 HEMODIALYSIS.
 Membrane material (allow only waste to
be transferred).
 Membrane stacking.
 Pump design.
 Safety if membrane leaks.
 Flow rate of dialysate.

23.  Disposable membrane vs. Cleaning.
 Can it be made wearable?
 Alternative present.

24. Conclusion and Summary
 The chemical engineering profession is too
diverse to fall into a single category.
 It ranges from mathematical analysis to
plumbing.

25. So, did I ruin my life by becoming a
Chemical Engineer ???????
Actually, no…..
Spend some time exploring the many
possibilities available to chemical
engineers

26.  Attorney
Specializes in intellectual property law, patent law,
technology transfer, environmental compliance, and
safety issues. Patent attorneys obtain patents for clients
and monitor the marketplace for possible patent
infringements.
 Biomedical Specialist
Works alongside physicians to develop systems that track
critical chemical processes in the body. Biomedical
specialists may be involved in the design of artificial
organs, such as hearts and lungs.

27.  Computer Applications and
Technology Engineer
Designs instrumentation and programs systems to control
certain processes. Automation engineers may develop
ways to monitor a series of interactive steps in chemical,
petroleum, or biotechnology facilities.
 Consultant
Works for many different customers and brings specialized
knowledge to individual projects. Consultants in a
company may work with teams of engineers to design
and construct an expansion for a company. Most
consultants have several years of professional
experience.

28.  Process Design Engineer
Designs manufacturing facilities and the equipment and
materials used inside. Process design engineers work
with teams of engineers to develop new or improved
processes to meet a company's production needs.
 Environmental Engineer
Develops techniques to recover usable materials, and
reduce waste created during manufacture of a product.
Environmental engineers design air pollution control and
wastewater treatment systems, waste storage and
treatment facilities, and soil and groundwater clean-up
systems. They also may be responsible for monitoring all
systems in a facility for compliance with environmental
regulations.

29.  Technical Manager
Responsible for the engineering staff and programs at a
facility. Manages people, research programs, and daily
operations of the engineering functions. Technical
managers may oversee R&D. With plant managers, they
may plan and implement the funding and expansion
programs necessary to develop a new product.
 Business Coordinator
Develops budgets and capital projections for a facility or
process. Business coordinators work closely with
production and design team members to determine the
exact needs of a new process, then plan the capital
needs necessary to implement the program.

30.  Plant Process Engineer
Provides technical support to staff and troubleshoots
processes in a production facility to keep a plant running
efficiently. Plant process engineers work closely with
equipment operators to get feedback on the operations
of each process and determine how to avoid shut-
downs. They may also be involved with design work for
improving methods of production.
 Process Safety Engineer
Designs and maintains plants and processes that are safer
for workers and communities. Process safety engineers
may conduct safety analyses of new and existing
equipment, and train employees on how to operate a
new piece of equipment safely.

31.  Product Engineer
Follows the production cycle of a particular product to
ensure it is meeting specification. Product engineers may
work with marketing and R&D to ensure that a product
will meet the needs of customers, then see the product
through production. They may work on new products or
variations of existing products.
 Manufacturing Production Engineer
Responsible for the day-to-day operation of a specific
manufacturing process. Manufacturing production
engineers work directly with operators to ensure that a
particular product is made according to specifications.

32.  Professor
Instructs students and conducts research. Professors may
teach several classes in chemical engineering, be
members of university committees, and conduct
research using government, corporate, or private
funding.
 Project Engineer
Oversees the design and construction of specific processes
in a facility. After construction, they may assist in
equipment testing, operator training, and plant start-up.

33.  Quality Control Engineer
Monitors the manufacture of product to ensure that quality
standards are maintained. Quality control engineers may
bring samples of a product in from a field test, or from a
normal application, and test them to determine how
specific properties -- such as strength, color, and
weatherability -- change over time.
 Regulatory Affairs Engineer
Researches, develops, and monitors policies and
procedures to ensure the proper handling of chemicals
and chemical components. Chemical engineers in
regulatory affairs may be government employees who
study the environmental impact of a new chemical, then
recommend appropriate guidelines for the chemical's
use.

34.  Research and Development Engineer
Seeks out new and more efficient ways of using and
producing existing products. Explores and develops new
processes and products and determines their usefulness
and applicability. Chemical engineers working in R&D
may work with chemists and other engineers to develop
a new process or new product that will better meet
customer needs.
 Sales and Marketing Engineer
Assists customers in solving production and process
problems by providing products and services to meet
their specific needs. Chemical engineers in sales use
their technical knowledge to sell chemicals, equipment,
and other products, and provide follow-up services and
training, where needed.

35.  Technical Services Engineer
Works with customers, usually on-site, to solve production
problems caused by a process or machine. Chemical
engineers working in technical services may represent the
manufacturer of a machine to determine why it is not
performing as designed. They often must understand the
other steps in the production process to determine if there is
a breakdown in another area.
 Alternatives
Because of their training and skills, chemical engineers make
strong candidates for jobs not traditionally associated with
chemical engineering: sales, technical writing, law, insurance,
real estate, publishing, finance, technical services, and
government. Even within the "typical" industries, many
engineers are surprised (and often pleased) to learn that their
responsibilities regularly include management, marketing,
packaging, distribution, strategic planning, training, and
computer programming.

36. O.K.…
but where can I find a job ???
A variety of industries employ chemical engineers,
representing a diverse range of products,
employers, and services.

37.  Chemical Process Industries
The focus of companies in this industry is on the development, extraction,
isolation, combination, and use of chemicals and chemical by-products.
Chemical engineers design and operate processes and systems to
combine, transport, separate, handle, recycle, and store them.
This industry consists of several specialty areas:
• Agricultural Chemicals
• Specialty Chemicals
• Industrial Gases
• Paints, Varnishes, Lacquers, Pigments, and Inks
• Petrochemicals
• Petroleum Products
• Plastics, Synthetic Resins, and Composites
• Polymers
• Pulp and Paper
• Rubber and Rubber Products
• Soaps, Detergents, Perfumes, Fats, Oils, and Cosmetics
• Synthetic Fibers, Textiles, and Films

38.  Biotechnology
This area uses living cells, materials produced by cells, and
biological techniques developed through research to
create products for use in other industries. This field has
produced antibiotics, insulin, interferon, artificial organs,
recombinant DNA, techniques for waste reduction and
recycling, and hybrid plants that are insect resistant.
Chemical engineers develop and design the processes to
grow, handle, and harvest living organisms and their
byproducts.

39.  Design and Construction
This field works with other industry sectors to design and
build facilities, specify machinery, and design and
troubleshoot processes that allow companies to operate
safe and efficient plants. Chemical engineers are
involved with process design and project management
and work closely with other engineering disciplines.

40.  Electronics
Chemical engineers in the electronics industry are
involved with material development and
production, process control equipment design,
and the manufacturing of microchips and
intricate circuitry. Chemical engineers have
contributed to the industry by producing
components that better dissipate heat and
operate faster.

41.  Environmental Safety & Health
Every process involving use and manipulation of
raw materials produces some by-products.
Chemical engineers minimize the production of
by-products (or find an appropriate use for
them) through process monitoring and control,
as well as by designing more efficient processes.
Chemical engineers are involved in waste
treatment and disposal and process safety and
loss prevention.

42.  Food and Beverages
This industry includes the handling, processing,
preparing, packaging, and preserving of food
and beverages. Chemical engineers formulate
new products to meet consumer demand,
change ingredients to improve flavor, adapt
handling processes to ensure more consistent
texture, and freeze-dry products or design
aseptic packaging to enable a longer shelf life.

43.  Fuels
This industry comprises petroleum and petroleum
products production and refining, as well as
nuclear and synthetic fuels. Typically known for
their work in refineries, chemical engineers are
also involved in developing alternative energy
sources, working on production processes,
environmental monitoring, research and
development, and process safety.

44.  Advanced Materials
Several industries (most notably aerospace,
automotive, glass, ceramics, electronics,
refractories, metals, metallurgical products,
minerals processing, and photographic products)
employ chemical engineers to help develop
materials. Chemical engineers manipulate the
weight, strength, heat transfer, reflectivity, and
purity of substances to produce materials with
unique properties.

45.  Miscellaneous
The technical training received by chemical
engineers makes them well suited for positions
in business, finance, insurance, law, publishing,
education, and government. Chemical engineers
manage, analyze, and insure businesses in the
chemical process industries. U.S. government
employers include the Environmental Protection
Agency, the Department of Energy, the U.S.
Navy, NASA, the Nuclear Regulatory
Commission, and the Department of Agriculture.

46. Professional Organizations
 Professional organizations and associations
provide a wide range of resources for planning
and navigating a career in Chemical Engineering.
 Associations promote the interests of their
members and provide a network of contacts that
can help you find jobs and move your career
forward.
 They can offer a variety of services including job
referral services, continuum in education
courses, insurance, travel benefits, periodicals,
and meeting and conference opportunities.

47. During the past Century, chemical engineers
have made tremendous contributions to
our standard of living. To celebrate these
accomplishments, the American Institute
of Chemical Engineers (AIChE) has
compiled a list of the "10 Greatest
Achievements of Chemical
Engineering."

48.  The Atomic
science.
 Plastics.
 Artificial Organs.
 Drugs.
 Synthetic Fibers.
 Liquefied Air.
 The
Environment.
 Food.
 Petrochemicals.
 Synthetic
Rubber.

49. Early Industrial Chemistry

50. Before the advent of the industrial revolution (18th
century), the demand for industrial chemicals was
largely met by batch processing, which is
something like cooking – one added the needed
ingredients at the beginning of the process into a
vessel, arranged a sequence of conditions such as
temperature, pressure etc., tested the quality of the
product after sufficient time, and if deemed good
enough, stopped the process, opened the vessel and
took out the contents, finally subjecting them to further
purification steps in order to get a saleable product
answering to a set of specifications. In such processing,
small batch-to-batch variations in quality could not be
eliminated, but the process could be operated with even
a limited level of understanding of how chemistry
operated on a large scale.

51.  A nation's industrial might could be gauged solely by
the vigor of its sulfuric acid industry.
 During the 19th Century sulfuric acid (Oil of Vitriol) &
"Fuming" Sulfuric Acid (Oleum) (H2SO4) was
necessary in the production of alkali salts and
dyestuffs, two giants of the day. Today the largest
single use is in the manufacture of fertilizers. It is also
necessary in petroleum purification, steel production,
electroplating, and automobile batteries. The
production of TNT (trinitrotoluene), nitroglycerin,
picric acid, and all other mineral and inorganic acids
require sulfuric acid.
 "Fuming" sulfuric acid contains excess amounts of
sulfur trioxide and fumes when exposed to air; hence
it's name.

53.  English industrialists spent a lot of time, money, and
effort in attempts to improve their processes for
making sulfuric acid. A slight savings in production
led to large profits because of the vast quantities of
sulfuric acid consumed by industry.
 Lead-Chamber Method was developed in England
in 1749 to make sulfuric acid. A mixture of sulfur
dioxide (SO2), air, water, and a nitrate (potassium,
sodium, or calcium nitrate) are mixed in a large lead
lined chamber thereby forming sulfuric acid.
 Of these ingredients the nitrate was frequently the
most expensive; it had to be imported all the way from
Chile.

54.  In 1859, John Glover helped solve this problem by
introducing a mass transfer tower to recover some of
this lost nitrate. In his tower, sulfuric acid (still
containing nitrates) was trickled downward against
upward flowing burner gases. The flowing gas
absorbed some of the previously lost nitric oxide.
Subsequently, when the gases were recycled back into
the lead chamber the nitric oxide could be re-used.
 Thus John Glover can be considered the first Chemical
Engineer.
 Sulfuric acid produced in this way, and labeled acid, is
only about 62 to 70 % H2SO4. The rest is water.
 About 20 percent of all sulfuric acid is now made by
the lead-chamber process, but that percentage is
diminishing.

55.  The second method of manufacturing sulfuric acid, The
contact process, which came into commercial use at the
beginning of the 20th century.
 The primary impetus for the development of the contact
process came from a need for high strength acid and oleum
to make synthetic dyes and organic chemicals.
 The pace for its development was accelerated during World
War I in order to provide concentrated mixtures of
sulphuric and nitric acid for explosives production.
 A paper by Winkler in 1875 awakened interest in the
contact process, first patented in 1831.
 Winkler claimed that the conversion of SO2 to SO3 could
only be obtained with stoichiometric, undiluted ratio of
SO2 and O2, which was erroneous.

56.  Meanwhile, other German firms expended a tremendous
amount of time and money on research.
 This culminated in 1901 with Knietsch’s lecture before the
German Chemical Society revealing some of the
investigations carried out by the Badische Anilin-und-
Soda-Fabrik. This described principles necessary for
successful application of the contact process.
 It depends on oxidation of sulfur dioxide to sulfur trioxide,
SO3, under the accelerating influence of a catalyst.
 Finely divided platinum, has two disadvantages:
 It is very expensive.
 It is vitiated by certain impurities in ordinary sulfur
dioxide that reduce its activity (poisoned).

57.  Many sulfuric-acid producers use two catalysts in tandem;
 first, a more rugged but less effective one like iron oxide
or vanadium oxide to bring about the bulk reaction;
 then, a smaller amount of platinum to finish the job.
 At 400° C (752° F), the conversion of sulfur dioxide to
trioxide is nearly complete.
 The trioxide is dissolved in concentrated sulfuric acid, and
at the same time a regulated influx of water maintains the
concentration at a selected level usually about 95 percent.
 By reducing the flow of water, a product with more SO3
than shown in the formula H2SO4 may be made. This
product, called fuming sulfuric acid, or oleum, is needed
in some organic chemical reactions.

58.  In 1963, Bayer AG introduced the first large scale use of
the Double Contact (double absorption) process.
 In this process, SO2 gas that has been partially converted to
SO3 by catalysis is cooled, passed through sulphuric acid to
remove SO3, reheated, and then passed through another
one or two catalysts beds.
 Thus, overall conversion can be increased from about 98%
to 99.7%, thereby reducing emissions of unconverted SO2
to the atmosphere.
 The stoichiometric relation between reactant and product
for the contact process may be represented as follows:
SO2 + ½ O2 ↔ SO3
SO3 + H2O → H2SO4

59.  The first equation:
 Exothermic
 Reversible
 Shows a decrease in molar volume on the right hand side.
 To improve equilibrium or driving force for the reaction, the
industry has attempted one or a combination of the
following process design modifications:
 Increasing concentration of SO2 in the process gas stream.
 Increasing concentration of O2 in the process gas stream
by oxygen enrichment.
 Increasing the number of catalyst beds.
 Removing the SO3 product by interpass absorption.
 Lowering catalytic converter inlet operating temperature.
 Using better catalyst.
 Increasing the catalytic converter operating pressure.

62. Heat Exchanger
 Heat Exchanger is a device built for efficient heat transfer
from one fluid to another, whether the fluids are separated
by a solid wall so that they never mix, or the fluids are
directly contacted. They are widely used in refrigeration, air
conditioning, space heating, power production, and
chemical processing. One common example of a heat
exchanger is the radiator in a car, in which the hot radiator
fluid is cooled by the flow of air over the radiator surface.
 For efficiency, heat exchangers are designed to maximize
the surface area of the wall between the two fluids, while
minimizing resistance to fluid flow through the exchanger.

63.  Heat exchangers may be classified according to their flow
arrangement.
 In parallel-flow heat exchangers, the two fluids enter
the exchanger at the same end, and travel in parallel to
one another to the other side.
 In counter-flow heat exchangers the fluids enter the
exchanger from opposite ends. The counter current
design is most efficient, in that it can transfer the most
heat. See countercurrent exchange.
 In a cross-flow heat exchanger, the fluids travel roughly
perpendicular to one another through the exchanger.

64. Types of Heat Exchangers
 Many types, the most two important types are:
 A typical heat exchanger is the shell and tube heat
exchanger which consists of a series of finned tubes,
through which one of the fluids runs. The second fluid
runs over the finned tubes to be heated or cooled.
 Another type of heat exchanger is the plate heat
exchanger. It directs flow through baffles so that the
fluids are separated by plates with very large surface
area. This plate type arrangement can be more efficient
than the shell and tube.

67. Alkalies
 Sodium Carbonate (Soda ash, Washing Soda) (Na2CO3) &
Sodium Bicarbonate (baking soda) (NaHCO3) are used to
manufacture glass, soap, textiles, paper, and as a disinfectant,
cleaning agent, and water softener.
 Potassium Carbonate (Potash) (K2CO3) Produced by slowly
running water through the ashes of burned wood (leaching)
and boiling down the resulting solution in large pots ("pots of
ashes" hence the name Potash). Potash can be used in place of
Sodium Carbonate (soda ash) to make glass or soap.
 Alkali Hydroxides (usually just called "Alkali") are used to
produce glass, paper, soap, and dyestuffs for textiles, aid in oil
refining, make bleaching compounds, and preparing leather.
Sodium Hydroxide (NaOH) (caustic soda) and Potassium
Hydroxide (KOH) (caustic potash) are the two most common
and important chemicals in this class.

68. Sodium Carbonate
 White crystalline solid, M.Wt. 105.99
 It is the 11th largest world commodity chemical, in 1989 33
million metric tons were produced (9 million in USA).
 About 75% is synthetic ash made from sodium chloride via
the Solvay process. The remaining 25% is produced from
natural sodium carbonate bearing deposits.

69. Leblanc process
 The Leblanc process was a batch process in which
sodium chloride was subjected to a series of
treatments, eventually producing sodium carbonate. In
the first step, the sodium chloride was heated with
sulfuric acid to produce sodium sulfate (called the salt
cake) and hydrochloric acid gas according to the
chemical equation
2 NaCl + H2SO4 → Na2SO4 + 2 HCl
 This chemical reaction had been discovered in 1772 by
the Swedish chemist Carl Wilhelm Scheele.

70.  Leblanc's contribution was the second step, in which the
salt cake was mixed with crushed limestone (calcium
carbonate) and coal and fired. In the ensuing chemical
reaction, the coal (carbon) was oxidized to carbon dioxide,
reducing the sulfate to sulfide and leaving behind a solid
mixture of sodium carbonate and calcium sulfide, called
black ash.
Na2SO4 + CaCO3 + 2 C → Na2CO3 + CaS + 2 CO2
 Because sodium carbonate is soluble in water, but neither
calcium carbonate nor calcium sulfide is, the soda ash was
then separated from the black ash by washing it with water.
The wash water was then evaporated to yield solid sodium
carbonate.

71. Solvay Process
 The disadvantages of the Leblanc process prompted
Ernest Solvay (1838-1922) to develop and commercialize
a procedure using ammonia to produce soda ash from salt
and limestone.
 These raw materials are more readily available than natural
alkali.
 The first plant using the solvay process was built in 1863;
this process or variations are in use in much of the world in
the 1990s.
 The overall chemical reaction:
2NaCl + CaCO3 → Na2CO3 + CaCl2

72.  The process goes as follows:
NaCl + NH3 → ammoniated brine.
Ammoniated brine + CO2 → NaHCO3 + NH4Cl
2NaHCO3 → Na2CO3 + CO2 + H2O
CaCO3 → CaO + CO2
CaO + NH4Cl → 2NH3 + CaCl2 + H2O

74. Pollution Issue
 The Leblanc process plants were decidedly not
environmentally friendly.
 The process of generating salt cake from salt and sulfuric
acid released hydrochloric acid gas, and because this acid
was industrially useless in the early 1800s, it was simply
vented into the atmosphere.
 In addition, for every 8 tons of soda ash, the process
produced 7 tons of calcium sulfide waste. This solid waste
had no economic value, and was piled in heaps and spread
on fields near the soda works, where it weathered to release
hydrogen sulfide, the gas responsible for the odor of rotten
eggs.
 Last used is 1916-1917.

75.  In 1863 the Alkali Works Act was initiated by the
British government. It set limits for chemical
emissions in an attempt to reduce the pollution that
had devastated the "Midland" region of England for
nearly a century and a half.
 As the 1700's expired, and English trees became
scarce, the only native source of soda ash remaining
on the British Isles was kelp (seaweed) which
irregularly washed up on its shores. Imports of Alkali,
from America in the form of wood ashes (potash) or
Spain in the form of barilla (a plant containing 25%
alkali) or from soda mined in Egypt, were all very
expensive due to high shipping costs.

76. Setting the Stage for a New Profession,
Chemical Engineering in 1888.
 George Davis:
 Unremarkable Alkali Inspector.
 In 1880 George Davis proposed the formation of a
"Society of Chemical Engineers“. While the
attempt was unsuccessful, he continued to promote
chemical engineering undaunted.
 In 1884 Davis became an independent consultant
applying and synthesizing the chemical knowledge
he had accumulated over the years.

77.  In 1887 he molded his knowledge into a series of 12
lectures on chemical engineering, which he presented at
the Manchester Technical School.
 This chemical engineering course was organized around
individual chemical operations, later to be called "unit
operations.“
 His lectures went far in convincing others that the time for
chemical engineering had arrived.

78. Chemical Engineering in the United
States
 Only a few months after the lectures of George Davis,
Lewis Norton , a chemistry professor at the
Massachusetts Institute of Technology (MIT) initiated
the first four year bachelor program in chemical engineering
entitled "Course X“.
 University of Pennsylvania and Tulane University soon
followed in 1892 and 1894 respectively.
 The competition between manufacturer necessitated things
such as; continuously operating reactors (as opposed to
batch operation), recycling and recovery of unreacted
reactants, and cost effective purification of products.

79.  The new chemical engineers were capable
of designing and operating the increasingly
complex chemical operations which were
rapidly.