摘要 |
A heater for heating a process fluid in which a cylindrical main chamber has a number of high intensity burners mounted therein to project products of combustion into the main chamber in a direction transverse to the axis of the main chamber. An annular secondary chamber surrounds the longitudinal walls of the main chamber, a first set of heat exchanger tubes being provided in the main chamber and a second set in the secondary chamber. Gases flowing from the burners pass over the first set of heat exchanger tubes, and then through at least one inlet to the secondary chamber, where they pass over the second set of heat exchanger tubes and out through a flue outlet at the top. A refractory shield may be provided adjacent the burners to guide the gases from the main chamber into the secondary chamber, and a further heat shield may be provided between the main chamber and the secondary chamber. |