Direct fired heater utilizing particulates as a heat transfer medium

Abstract

This invention relates to a means of heating a process fluid to elevated temperature thru use of heat resistant particulates as a heat transfer medium. Down-ward flowing particulates, enter the top of a refractory lined containment vessel, and are heated to elevated temperature by direct contact with an up-flowing stream of hot combustion products, generated by side wall burners located at the bottom of the containment vessel. The heated particulate stream is separated from the combustion gas stream at the bottom of the containment vessel and the spent combustion gas is directed to a downstream tubular convection section for heat recovery and for further processing to recover vaporized process fluid, as in the case of liquid feed preheating for delayed coking, or for heat recovery only, as in the case of gas cracking. The particulate stream is conveyed to the bottom of a second refractory lined containment vessel, by means of an incoming stream of process fluid, and is raised to the desired outlet temperature by direct contact with the particulate stream. The particulates are separated from the process fluid in a low velocity region located in an expanded section at the top of the second vessel, and the process fluid is processed further in downstream equipment. Spent particulates are returned to the top of the first vessel, completing a continuous cycle.