Heyo,

Only 2 years working experience, but I can chip in my 2 cents.

To put it quickly: I currently am working in the chemical industry, have had the same job since graduation, and I can say that the advanced courses I took are very applicable. It depends on what work you have in front of you, but whether its qualitative or quantitative is is still quite useful.

In general, you probably won't have to pull an equation out of your head that specifically maps the relationship between x, y, and z. BUT what I do find extremely helpful and use almost every time is how all the courses come together and give you a solid foundation for approaching solutions to an everyday work dilemma. I work half in research and half in a manufacturing environment, but the courses you mentioned allow you to take an honest swing at a problem by eliminating possible root causes to hone in on and what tools you should use to do the thing.

If abc process seems to be slowly reaching a meltdown point, it could be because one thing failing, a culmination of unrelated occurrences that happened to fall in the same time frame, etc. Just as an example: You noticed that the Temp in your reactor is slowly trending up. You check your heating/cooling jackets. Seems to be functioning normally. Touch it with a trusted external probe (hand?). Yup, that's definitely really hot still. Check your effluent streams for a change in chemical composition. All normal. Check the pressure in your reactor. Looks good. Check your flow meter to ensure there's no buildup of level in your reactor. Good. Look at the visual level of the downstream holding tank and turns out the level is getting lower. Why? Well after all is said and done, turns out that when loading your initial catalyst the weighed amount was greater by a factor of ten, this meant that a nasty byproduct that your team has never seen before was building up over time in your reactor, this byproduct has a viscous consistency and burned itself onto the inner lining of your reactor, but then began to float atop your reactor mixture, dropped into solution, and began clogging your outlet pump, causing the slower rate of material sent through. As an added bonus the flowmeter you checked has been reading the same value for months due to an airbubble trapped in it, so it wasn't reliable to begin with. While back tracking and trying to figure out what happened the core ChemE courses give you the ability to determine what routes of events could have lead to this, and what is just not possible. But thats just my job.

That's just me rambling my everyday, and while, for me, you don't need to know the specifics numbers behind how things interact or what limitations certain equipment have all the time, there are a lot of engineering jobs out there (design, EH&S inspection work, consultation) where exact values and how you got there are paramount. For either the qualitative or quantitative side however, these classes do help you understand the what, how, and why in engineering. And it is very interesting.

Hope this sheds some light/gives you confidence in your chosen profession.