Abstract: A process including preheating a hydrocarbon feed in a first preheat zone of a convection section, recovering a preheated hydrocarbon stream; heating the preheated hydrocarbon stream in a secondary transferline exchanger, recovering a heated hydrocarbon stream; feeding the heated hydrocarbon stream to a second preheat zone of the convection section to vaporize a portion of heated hydrocarbon stream, recovering a cracking feedstream; cracking hydrocarbons in the cracking feedstream in one or more coils in a radiant section, recovering a cracked hydrocarbon product; and cooling the cracked hydrocarbon product in the secondary transferline exchanger in indirect heat exchange with the preheated hydrocarbon stream, recovering a cooled hydrocarbon product stream.

Abstract: A system for cracking hydrocarbons including a fired heater having a radiant section and a convective section. The radiant coil is disposed within the radiant section of the heater, the radiant coil having three to seven rows of tubes, wherein each row comprises two multi-pass tubes, and wherein the multi-pass tubes of the three to seven rows of tubes are collectively disposed symmetrically or pseudo symmetrically within the radiant section of the heater. The system further including a transfer line exchanger fluidly connected to an outlet tube of each of the three to seven rows of tubes.

Abstract: Catalytic dehydrogenation wherein feed is passed in one direction through the bed in a first cycle and heating gas is passed in an opposite direction in a second cycle to provide the endothermic heat of reaction and regenerate catalyst. The operation is controlled to balance properly heat absorbed during dehydrogenation and heat input during regeneration; e.g., by having catalyst of different activities over the length of the bed.

Abstract: A quench cooler or transferline heat exchanger for quenching the effluent from a hydrocracking furnace has an inlet coupling between the cracking furnace tubes and the tubes of the quench cooler which splits the flow into a plurality of branches. The flow passages are configured to initially decelerate and then re-accelerate the gas. This involves a conical diverging diffuser section and then a tapered and branched converging section. The cross sectional transitions are smooth to avoid dead spaces and minimize pressure loss.