I worked in a power plant for 20 years and have seen a lot of steam. I agree with Jed it looks like low temperature steam to me. It is hard to see as it comes out of the line and it does condense into the slight mist that you see against the black background.
I am not surprised to see some water in the line. Some steam should condense to keep the line hot. That why there are steam traps on many steam lines this happens all of the time with low temperature steam. Highly super-heated steam is not visible. This steam is not super-heated. The chimney is just a steam separator like on the top of steam locomotive. With such a small chimney I am sure that some water is ejected with the steam. By the looks of the steam coming out of the hose it is not a lot. Frank Z
