Patent ID: 9011791
Filing Date: 2015-04-21
Classification: B01J,C04B,C10G

Abstract:
1. A cracking furnace construction, comprising: a firebox defining a chamber having refractory walls, and containing a plurality of heat generating burners disposed within the firebox chamber, each refractory wall having an internal surface exposed to heat generated by the burners; a process tube structure having at least one process tube disposed within the firebox chamber, and in fluid communication therethrough, permitting fluid to pass through the firebox chamber while fluidly contained solely within the process tube structure, wherein the at least one process tube has an internal surface defining an interior space, and an external surface directly exposed to the heat generated within the firebox chamber for thermal communication therethrough; the at least one process tube extending from a first end to a second end allowing fluid communication therethrough; at least one opening to receive a hydrocarbon containing feed stock fluid mixture into the process tube structure through the first end of the at least one process tube wherein the feed stock fluid mixture flows through the interior space of the at least one process tube from first through second ends heated therein by thermal communication through the at least one process tube, and discharging a cracked hydrocarbon product fluid mixture out of the second end of the at least one process tube, and at least one thermal protective layer consisting of a high emissivity coating disposed on the external surface of the at least one process tube, or on the internal surface of the at least one process tube, or combinations thereof, wherein the at least one thermal protective layer contains a. from about 5% to about 30% of an inorganic adhesive, from about 45% to about 92% of a filler, and from about 1% to about 20% of one or more emissivity agents, or b. from about 5% to about 35% of colloidal silica, colloidal alumina, or combinations thereof; from about 23% to about 79% of a filler, from about 1% to about 20% of one or more emissivity agents.