Hello, guys.
I'm a chemistry graduate, but not a native English speaker. Now I am reading a book, where I met with the next sentence: "The acetylene PURGE from the butadiene extraction unit contains a significant amount of butadiene". The process of the butadiene extraction is not clarified in the book and I can find no other source,which might enlighten me as to the subject. Could you please explain the meaning of the word "purge" in regard to this sentence? I can't exactly grasp it myself. Thank you.