At risk of telling you stuff you already know, steam was used extensively in the textile industry both to drive machinery via line shafting and flappy belts - I can just about remember the last mill to use mule spinning in the Colne Valley where a neighbour's father worked and yes, we were allowed into the room where the mules were and somehow survived - and in the cloth processing.
At the front end it would be used in the washing and dyeing of the yarn and at the back end in the finishing* room. I assisted on the rotary press - a 4ft diameter drum heated by steam under which the pieces (the lengths of woven cloth, 60-70yds long) passed, effectively a giant iron - during one holiday job and spent what would nowadays be called a gap yah running the blowing machine where the piece would be rolled round a perforated 4ft dia. drum between layers of a fine heavy cotton (I think) cloth - called a blowing wrapper - and steam under pressure blown through it from the drum to encourage felting of the cloth.
So even after the machinery was converted to electric motors there was still a need for steam, George Mallinsons at Linthwaite had two(?) oil fired Lancashire boilers running until the mill closed around 1980. I would guess the boiler works serviced this need for steam. I can ask my dad next time I see him if he knows anything about it. He's 91, lived in the Colne Valley all his life and worked in the textile industry from school to retirement apart from national service.
*My dad's occupation is listed as cloth finisher on his marriage certificate.