Propane fired gas commercial and home-built kilns are quite common. However this process seems to generate more questions than any other, especially on the subject of propane tanks. If the propane tank is not large enough, for example, it will freeze up and be unable to supply the necessary fuel. People often underestimate the number of tanks needed for a firing and the rate at which a given tank can supply gas.
The Clayart discussion group on the Internet has a lot of knowledge people in this area.