Abstract: A process for the oxidative dehydrogenation of ethane is disclosed. The process may include: contacting an ethane feed and an oxygen-containing gas in the presence of an oxidative dehydrogenation catalyst in an oxidative dehydrogenation reaction zone under conditions to oxidatively dehydrogenate at least a portion of the ethane to produce a product stream comprising ethylene, carbon oxides, water, and unreacted oxygen and ethane, wherein an oxygen concentration in the product stream is at least 0.1 mol %; contacting the product stream with an oxygen elimination catalyst in an oxygen elimination reaction zone to combust at least a portion of the oxygen; recovering from the oxygen elimination reaction zone an effluent having a reduced oxygen content; separating water from the effluent; separating carbon oxides and any non-condensable gas(es) from the ethylene and the unreacted ethane; and separating the ethylene from the unreacted ethane.

Abstract: A shell and tube heat exchanger, such as a vertical combined feed/effluent heat exchanger (VCFE), including: a shell having a fluid inlet and a fluid outlet; a plurality of baffles mounted in the shell to guide the fluid into a helical flow pattern through the shell; wherein a helix angle ? of a baffle proximate the inlet is different than a helix angle ? of a baffle proximate the outlet.