sugar refinery vs refinery

sugar refinery and refinery both are nouns.

Word	Noun	Adjective	Verb	Adverb
sugar refinery	Yes	No	No	No
refinery	Yes	No	No	No

As nouns, refinery is a hypernym of sugar refinery; that is, refinery is a word with a broader meaning than sugar refinery:

sugar refinery (noun)	refinery (noun)
a refinery for sugar	an industrial plant for purifying a crude substance