The way something is taught really shapes your perception of it.
I went through most of high school thinking that I hated physics. Turns out, I just hated IB exams. When senior year came around and I had to pick a major for college apps, I thought it was a no-brainer. I liked the concept of engineering: I read Walter Isaacson's biography of Steve Jobs and found myself much more drawn to Woz: the tinkerer, the workhorse, the creator. My own family, my dad and nanaji, were civil/environmental and electrical engineers respectively and hearing their war stories filled me with a sense of wonder. I knew I'd be an engineer: to me it was the pinnacle of work. You take the laws of nature, you build a deep understanding of them, and then you create ways to harness them to the end of producing some benefit.
I knew I wanted to be an engineer, but having gone through a physics curriculum that left a sour taste in my mouth I wanted to stay as far away from physics as possible. Thus (in my then-underresearched frame of mind): chemical engineering. It has engineering in the name, it says chemical (and I knew I liked chemistry) so I'll probably not have to do as much physics as if I did mechanical or electrical. Dear me what a terrible presumption to have.
So what exactly is chemical engineering? Chemical engineering develops and applies processes that take inputs (materials, energy) and transform them into outputs: more useful products or materials. This bridges studying applied math, statistics, material and energy balances, heat and mass transfer, materials and biomaterials science, reaction kinetics and so many more physics-heavy subjects.
ChemE is without a doubt one of the most versatile undergraduate degrees you can study. It shares the same onboarding curriculum as other engineerings: Calc 1,2,3, Differential Equations and linear algebra; Physics 1, 2; some basic programming courses and of course chemistry. Chem 1, 2 (same as everyone else) but you'll probably need to also take OChem 1, 2, Physical Chemistry 1 and potentially 2.
The key difference is that of scale: chemists can take a new liquid soap formulation that they've made in a lab and hand it off to chemical engineers. A biochemist can discover a new enzyme that produces a certain desirable antiviral activity. Physicists or materials scientists can create a single photovoltaic cell in a cleanroom fabrication lab. Now chemical engineers need to figure out how to build it up at scale to produce 1000s of bottles; a whole manufacturing facility of this vaccine; how to produce a whole array of those photovoltaic cells. You can't just add more stuff in a bigger vat and hope it works, this is where the specialized knowledge of chemical engineering comes in, but you definitely need that basis of chemistry to understand the principle that you're trying to scale up.
Take home brewing vs industrial brewing. Home brewing, you can make do with some glass jugs, a dark place, some yeast, a cheescloth filter, and time. But industrially, you need to make the same batch every single time. You're concerned with the sizing and piping, heat transfer cooling jackets, all the sensors for temperature and flow and pressure, and the infrastructure to monitor and adjust process parameters on the fly.
Where a chemist would be concerned solely with the chemical processes occurring in the reaction vessel, a chemical engineer needs to additionally understand valves, controls, pipes, sizing, heat trace, etc.
To understand this distinction better, let me walk you through what you actually study:
- Material and Energy Balances (Acc = In - Out + Generation)
- Fluid mechanics (it's differential equations all the way down)
- Heat and Mass Transfer (further transport phenomena)
- Thermodynamics (evil)
- Control Systems (more fun with differential equations)
- Separations and bioseparations processes and principles
- Molecular Biology
- Applied Data Analysis (Prob\Stat)
- Kinetics/Biokinetics (guess what, more differential equations)
- Materials Science/Biomaterials
- Chemical process design
And various computational courses in between. Each of these courses reinforced the same core skill of breaking down complex systems into solvable problems, and being able to quickly gather domain knowledge to solve a problem you might not know how to solve yet.
Beyond the technical knowledge, chemical engineering taught me something equally valuable: because it's so damn hard, you find yourself naturally collaborating with your peers. I'd often be in office hours in the building basement, and half of my class would be trying to fit into the same room. We'd be sitting on the floor, swapping desks, whatever seating area fit them. And it was this shared experience of us struggling to improve our understanding of our classes that actually helped facilitate our own growth. When working on a heat transfer problem, one person might have an idea on what equations to use, or a creative reformulation of the problem and everyone would contribute their own way to advancing towards the solution.
Engineering is a largely collaborative process, especially in industry. Approaching difficult issues collaboratively is a skill that a difficult degree like ChemE helps you gain.
What studying Chemical Engineering gives you is an applied mathematical toolkit. You'll be able to understand constructs from first principles, and build up an understanding to be able to analyze and investigate it. You'll learn how to digest, statistically analyze, and build interconnected systems. It's probably one of the most interdisciplinary STEM courses that you can take for an undergraduate degree. You'll be dealt an odd but practical problem. For instance: I have a 6 pack of coke that's been sitting in a hot car for an afternoon during a hike, and there's a cool stream nearby: about how long will it take to cool the coke to drinking temperature if we stick them in the stream?
Career prospects differ between chemistry and chemical engineering degrees. Career-wise, chemical engineering opens doors to food engineering, brewing and distillation, biotech and pharmaceuticals, nuclear energy, alternative energy engineering, petroleum and mining engineering, environmental engineering, materials science, industrial chemicals, semiconductors/electronics... the list goes on. Advancement in pure chemistry often requires graduate school.
I don't think what you study as an undergraduate directly determines your career path. At the end, the greatest thing I gained from my degree in chemical engineering wasn't the ability to size heat exchangers or design distillation columns, but how to teach myself hard things that I don't know yet but want to learn.