The History of Chemical Engineering: Crash Course Engineering #5


Our world is made up of matter. And one way that we study matter is with chemistry. How we use that knowledge leads us to chemical
engineering. Chemical engineering is one of the broadest of the
engineering fields, focused not only on chemicals – which make up everything – but also on
developing and designing plants and processes
for manufacturing chemicals. Now, let’s imagine we’ve come up with an
amazing new product that we have to create
through a chemical process. It could be some new kind of personal water
purifier, or makeup that lasts as long as you want
it to, or a revolutionary clothing material. Whatever it is, we’re going to have to go
through some steps before we all get rich. Once we’ve designed our product, we’ll need
to create a facility where we can make it. And in order to know how to do that, it
would help if you understand a little about
the history of chemical engineering. [Theme Music] To begin, let’s dispel a common assumption:
that chemical engineering is simply chemistry
applied to engineering. Sure, there’s a lot of chemistry involved, but the
engineering side has a lot to do with answering
questions, like “What can we do with these chemicals?
How can we make them? Where can we go from here, and What are the
possibilities?” Chemical engineering got its unofficial
start back around the time of the American
Revolutionary War. During the war, blockades were put up to stop
trade between the American colonies and Europe. France was especially affected by these blockades,
because America is where it got its supply of sodium
carbonate, also known as soda ash. At the time, soda ash was used for a whole
bunch of things, from cooking, to manufacturing
glass and paper, to making soap. Since France couldn’t get sodium carbonate
from its normal trade routes, the French Royal Academy offered up a prize in 1775
to anyone who could make sodium carbonate from
sodium chloride – which we know as common salt. It took about 15 years, but a French chemist
and physician named Nicolas Leblanc finally
figured out how to do it around 1789. His methods, now known as the Leblanc Process, first
heated sodium chloride with sulfuric acid to produce
sodium sulfate, which was called the salt cake. The salt cake was then mixed with crushed
limestone and coal, and fired. This left the combination of sodium carbonate
and calcium sulfide, also known as black ash. The final step separated the sodium carbonate
from the black ash by washing it with water,
which was then evaporated. We call this extraction process lixiviation. Leblanc’s process became the forerunner of
modern chemical manufacturing, and paved the
way for future chemical engineers to come. By 1791, he opened up a small factory in Saint
Denis and began large-scale production of soda ash. But his plant was soon taken over by revolutionaries
during the French Revolution, who also released his
trade secrets. While this process was revolutionary in its
own right, it was pretty bad for the environment. It produced a ton of waste that smelled rather
putrid. Since chemical processes can often have
nasty byproducts, governments can often pass pollution legislation,
especially around big cities and bodies of water. But none of this has stopped the chemical
industry from growing. In the late 19th century, British chemist
George Davis worked as an inspector for the
Alkali Act, which was an early piece of environmental
legislation in response to the Leblanc process. The act required soda manufacturers to reduce
the amount of hydrochloric acid gas that they
released into the atmosphere. Around 1887, Davis gave a series of lectures
at the Manchester School of Technology. His talks formed the basis for his two-volume
Handbook of Chemical Engineering, which was
the first of its kind. There were already chemistry books written
for specific industries, like acid production
and brewing. But what made Davis’ work unique was that it organized
basic operations that are common to many industries,
like transporting liquids and gases or distillation. In the US, his work helped stimulate new ways
of thinking about chemical processes and sparked the creation of chemical engineering
degrees at universities around the country. Any chemical engineers that we work with to
help develop our product will likely have their
education rooted in Davis’ teachings. Around the turn of the 20th century, cars
were starting to become a regular part of
modern life. And soon chemical engineers were playing an
important role in their use, by making gasoline. Drills were already finding crude oil, but
that’s not gasoline. The oil needed to be refined. So we needed refineries, which were basically
giant chemical plants. Chemical engineers improved the process of
making gasoline by introducing methods like
cracking, where heavy hydrocarbon molecules
are broken down into lighter molecules by
heat and pressure. They also implemented the process of polymerization, where propylene and butylene are combined
into molecules of two or three times their
original molecular weight. With these improvements, gasoline became
more economically viable, which made gas cheaper
and owning a car less expensive. Now, large-scale chemical production like
this requires a lot of planning. So, as chemical plants develop, a big part
of chemical engineering becomes what we’ll
call “Unit Operations”. This was first introduced by the American
Arthur D. Little in 1915, and it breaks down each
part of a chemical plant into individual units. Do you need to get chemicals flowing from
one side of the plant to the other? Use pipes.
That’s a unit. And you’ll need pumps to drive the flow.
That’s another unit. Need to stimulate a reaction?
Use a reactor. Want to mix those chemicals together?
Go for a mixer. Need to separate them? Try distillation columns or maybe reverse
osmosis membranes. All of these are units, and they highlight
the key theories that chemical engineers need
to understand to keep a plant running. It’s important to think of processes as
a whole, but it will be just as important to break down
our chemical plant into unit operations when we
get to the manufacturing phase. Once engineers realized – in part thanks to
Little’s work – that all of these unit operations were founded
on basic principles, such as momentum transfer,
mass transfer, and thermodynamics, they could then become more creative in
how they manufactured chemicals. They no longer had to use the same equipment
for the same limited purposes. Instead, they could devise new ways of using
their tools and machines. This allowed chemical engineering to grow
into one of the broadest engineering fields. As recently as the 1970’s, the field was
much more narrow than it is now. Back then, around 80% of graduating
chemical engineers took jobs in the chemical
process industry and government. By 2000, that 80% had dropped to about 50%. One of the reasons for this was the emergence
of biotechnology. Heavily focused on research and development,
biotechnology engineering applies technology
to biological systems and living organisms. Once we know how and why biological processes
work, we can find ways to change, adapt, and control
them, with the aim of making our lives better. In a similar fashion, pharmaceutical and
healthcare companies also played a big role in
expanding what chemical engineers do. Every day, new drugs and medicines are made
and improved upon. Chemical engineers also work on how best to
deliver these drugs into our bodies. Some might best be injected, like insulin
or an epipen, while others work well in a
spray form, like an inhaler. A lot of chemical engineering goes into many
of the foods that we eat as well. We’ve had to figure out such dark magic
as getting corn syrup from corn and making
artificial sweeteners. We’ve found dairy substitutes and used plants
to make vegan and vegetarian meats that taste
like they came from an animal – kind of. This has all done wonders for people with
food allergies and dietary restrictions. There’s also a growing focus on the
environment and sustainable energy within
the field of chemical engineering. We want to both preserve what we already have
and find energy sources that won’t run out of power. So one source that’s closely related to chemical
engineering is biomass: renewable organic material
that comes from plants and animals. This ranges from wood and leftover crops,
to garbage and manure. As of 2016, biomass fuels provide about 5%
of the primary energy used in the United States. And chemical engineers play a big part in
figuring out what can be used as biomass and how
to best break it down to get energy from it. All of these developments in chemical engineering
are what will really give us the knowledge to make
our wonderful new product, whatever it is. We can improve upon what’s already there,
or make something truly revolutionary. When you’re a creator, the possibilities
are endless. So today we learned a lot about the history
of chemical engineering, starting with its
origins in sodium carbonate. We then talked about George Davis, the father
of chemical engineering, and his teachings. We moved on to oil refineries and chemical
factories, learning about the unit operations
behind them. We ended our lesson by talking about the newer
and emerging fields of biotechnology, pharmaceuticals
and food, and finally renewable energy. Next time we’ll learn about industrial and
biomedical engineering and how they’re
changing the world. Crash Course Engineering is produced in
association with PBS Digital Studios. You can head over to their channel to check
out a playlist of their latest amazing shows, like The Origin of Everything, Infinite Series,
and Eons. Crash Course is a Complexly production and this
episode of was filmed in the Doctor Cheryl C. Kinney
Studio with the help of these wonderful people. And our amazing graphics team is Thought Cafe.

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