I applied in-person. The process took 1 week. I interviewed at Celanese (New York, NY) in Mar 2018
Interview
Interviewed with 5 people lasted 3 hours. Typical behavior questions, provided history about company. Thought the interview went pretty good. But apparently they didn't. Should have known, when I asked for business card the manager said "I don't have one".
I applied online. The process took 1 day. I interviewed at Celanese (Irving, TX) in Nov 2013
Interview
They care more about whether you will fit in with the group then your overall resume. Make sure the interview is a conversation. They want to know if you will fall in line with what management wants. They kind of need "robots" (people that just do what they are asked to do and not ask questions.)