I think you have to remember this is a work of fiction, not a document telling people how to build these things. I think the standard should be "plausible" not "definitely doable". I also believe that things will work - but at an inefficient level. I'm not expecting them to jury-rig something with state-of-the-art efficiencies. To say that it is impossible to use a simple boiler to generate power flies in the face of Robert Fulton's efforts. The early steam designs were also inefficient, but as long as there is water and fuel, they can do useful work (and did).
I do thank you for challenging all of this. I'm trying to keep things in the plausible category. It's clear you think I've stepped over the line. If there is any way to help me get back to plausible in your mind, I'd appreciate it.