Disclosed is a shell and tube heat exchanger that includes, inter alia, an elongated cylindrical shell that defines a longitudinal axis for the heat exchanger and an internal chamber. The shell has at least one feed gas inlet and feed gas outlet formed in an outer wall for allowing a feed gas to enter and exit the internal chamber. At least one tube sheet is associated with an end of the elongated shell and a plurality of circular baffles are longitudinally spaced apart within the internal chamber of the shell for redirecting feed gas flow within the internal chamber. The heat exchanger also includes a tube bundle which has a plurality of tubes for allowing effluent gas to traverse from an inlet plenum through the internal chamber of the shell to an outlet plenum. Additionally, a shroud distributor is arranged and configured to direct feed gas flow from the feed gas inlet to the internal chamber proximate the at least one tube sheet. The shroud distributor has at least one angled cut formed in an end thereof for distributing the flow of feed gas.