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 method of manufacturing a heat exchange device having at least one heat exchange tube is disclosed. The method includes: determining a peak heat flux area of the at least one heat exchange tube; and disposing in the at least one heat exchange tube an flow enhancement device for creating a desirable flow pattern in a process fluid flowing through the at least one heat exchange tube; wherein the flow enhancement device is disposed in the at least one heat exchange tube upstream of or at the determined peak heat flux area of the at least one heat exchange tube.

Abstract: A pyrolysis heater particularly for the cracking of hydrocarbons in the production of olefins has a burner arrangement in the firebox which includes staged combustion low NOx hearth burners firing upwardly in the firebox adjacent to the walls. Wall stabilizing gas fuel injection tips, located at an elevation above the hearth burners, inject fuel upwardly between the walls and the flame from the hearth burners. This prevents rollover of the flame onto the process heater coil and overheating of the coil.

Abstract: A cracking furnace for the pyrolysis heating of an organic feedstock includes a heating section and at least one convection section. In one embodiment the furnace includes first and second convection sections positioned along opposite sides of the heating section. The openings for admitting flue gas to the convection sections can be at the top or the bottom of the heating section. In another embodiment the furnace includes a plurality of passageways for the communication of flue gas from the heating section to the convection section. The passageways can be positioned at the top or the bottom of the heating section. The passageways provide a more even flow of flue gas through the heating section by preventing recirculation of the flue gas within the heating chamber.

Abstract: A cracking furnace for the pyrolysis heating of an organic feedstock includes a heating section and at least one convection section. In one embodiment the furnace includes first and second convection sections positioned along opposite sides of the heating section. The openings for admitting flue gas to the convection sections can be at the top or the bottom of the heating section. In another embodiment the furnace includes a plurality of passageways for the communication of flue gas from the heating section to the convection section. The passageways can be positioned at the top or the bottom of the heating section. The passageways provide a more even flow of flue gas through the heating section by preventing recirculation of the flue gas within the heating chamber.

Abstract: A low pressure cryogenic process is disclosed for recovering C.sub.2 and heavier hydrocarbons and particularly olefins from a refinery offgas containing hydrogen, methane, nitrogen oxide in addition to the C.sub.2 and heavier hydrocarbons. The conventional high pressures are eliminated and the temperatures are maintained higher than the temperature at which nitrated gums can form while still maintaining high olefin recovery. The feed is deethanized or depropanized to remove the C.sub.4 and heavier hydrocarbons at a temperature above the nitrated gum formation temperature. The overhead is then demethanized in a column using an enriching zone above the rectifying zone with a feed of C.sub.2 or heavier paraffins between these two zones.