Great exposure! The discharge looks like silk. I love the sharp lines. I could do without the sepia, but that is just personal preference. Industrial shots like this are a passion of mine. especially nighttime shots.
Nice shot, I like the smoke and the overall contrast.
At the photo club they use the term mono-chrome since some of the folks use sepia or blue. With digital processing a few even tinkered with green or red.
We used to have a number of paper mills in our area and I always intended to go and get some long exposures of the steam chimneys, Unfortunately I never did and they have all closed now. Shame.
I don't mind the slight sepia processing, kinda makes it look like a thing of the past, which as I said, the paper industry in my area certainly and sadly is.