You must learn:
1 design of pressure vessels (very common)
2 welding foundation (materials, covered electrode selection, weld welding diagram, etc. )
3. Mechanics of materials (used to design shafts and structures)
4 theoretical mechanics (occasionally used)
5. Engineering thermodynamics (when designing mixing, calculate entropy and enthalpy, etc. )
6 familiar with GB150 GB151(common tools).
7 CAD
Principles of chemical engineering
9. Chemical fluid machinery (to be used in the design of power equipment, you need to be familiar with it as a whole)
10 heat exchanger and tower (familiar with design)
That's probably all for now. I hope it helps you. My humble opinion. Please refer to.
Actually, it's not that hard. Get used to it when you have more contact, and it will be simple. It's all the same pattern, and it's not difficult. I wish you an early learning.