I'm a chemical engineer (cheme) and have worked at a nuclear power plant and a pharmaceutical plant. Common tasks for me would be monitoring equipment conditions, efficiencies, diagnosing malfunctions, process modeling, and so on. Cheme’s can do a lot of things. I know some who are lab rats and some who work in oil refineries. Refineries are raw chemical engineering and will use every bit of knowledge you’ve ever acquired in college, but they pay well. A boss could ask a cheme to do anything from checking pressure drops across lines to finding a catalyst for a specific reaction and designing the reactor.
In college cheme’s focus a lot on thermodynamics, mass transfer, fluid dynamics, heat transfer, design, and of course, mathematics (calc I & II, multivariable calc, and differential equations). They also take a lot of chemistry, physics, reaction kinetics, maybe some biology, quantum mechanics, and controls. Many schools offer dual degrees with chemistry and make it easy to obtain minors in math and other subjects.
Chemical engineering is now becoming biochemical engineering because everyone believes this field will have a high demand. Some schools are even replacing their cheme departments for biocheme departments. I would be weary of such an intense focus in any engineering field.
Many statistics show cheme’s with the highest average salary with ME’s, EE’s and then CE’s following not too far behind.