You have to learn:
1 Pressure vessel design (very common)
2 Welding fundamentals (material, electrode selection, weld welding diagrams, etc. to use)
3 Mechanics of materials (design of shafts, structures to use)
4 Theoretical Mechanics (occasionally to use)
5 Thermodynamics of Engineering (design of stirring, etc., when calculating entropy, etc. to use)
5 Thermodynamics of Engineering (design of stirring, etc., to use)
6 Familiarize yourself with GB150 GB151 and so on (common tools)
7 CAD
8 Chemical principles
9 Chemical fluid machinery (dynamic equipment design to use, you need to be familiar with the whole)
10 heat exchangers, towers (familiar with the design)
Probably the first on these. I hope you can help. My humble opinion. Please refer to.
In fact, it is not very difficult, when you more contact, you will get used to it, it is simple. It's all a pattern, not too difficult. I wish you learn it soon.