Look very similar to the boilers at a animal products rendering plant I did some work at, three in one big boiler house, one in a separate boiler house. All running on tallow that they produced themselves, wans't the best smell but compared to the rest of the plant it was actually a breath of fresh air. The plant would be shutdown on a Monday morning for the boilers to be cleaned out, and other maintenance going on in the plant. They would then get back up and running somewhere late on in the afternoon and they would run right through 24/7 untill the weekend when the weeks worth of 'material' to process ran out. Sometimes they'd be running on a sunday, sometimes not. Interesting place once you got past the smell. I actually the other day managed to find a half bottle of alcohol hand sanitiser gel in the van from when I was working there.
As a side note, I wonder how they will fare with corona virus (I'm sure they must still be running, I cant see how it can be allowed for the stuff they take in to pile up for three weeks, that would be a public health issue in itself). I do wonder if due to the nature of it, that anyone from there who catches it might end up with very mild effects, I imagine being in that place keeps your immune system running at a reasonable rate, not immune to the particular virus of course, but effectivly on high alert to deal with whatever comes in pretty quickly