what boiler should i get

i have 2 coke ovens but i don't know how much creosote a liquid boiler would take but beyond that i don't know how the boilers work really. am i gonna have to have these running eternally or can i switch them on and off based on my need. can i store steam or something? anyhow what are your picks for boilers and tips relating to the new machines i can get with the advent of black steel