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Today we’ll cover the fourth and final of our core disciplines of engineering: chemical engineering. We’ll talk about its history and evolution going from soda ash competitions to oil refineries and renewable energies. We’ll also discuss some newer and emerging fields like biotechnology and pharmaceuticals.

Crash Course Engineering is produced in association with PBS Digital Studios:


“Basic Principles and Calculations in Chemical Engineering” by David Mautner Himmelblau, James B. Riggs


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CC Kids:
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.