riser pipe vs riser pipeline

riser pipe and riser pipeline both are nouns.

Word	Noun	Adjective	Verb	Adverb
riser pipe	Yes	No	No	No
riser pipeline	Yes	No	No	No

As nouns, riser pipe and riser pipeline are synonyms defined as:

Other synonyms of riser pipe include riser, riser main.

riser pipe (noun)	riser pipeline (noun)
a vertical pipe in a building	a vertical pipe in a building