A method of assembling a syngas cooler is provided. The method includes coupling at least one cooling tube within the syngas cooler, wherein the at least one cooling tube includes an inner surface that defines a flow passage therethrough, an opposite outer surface, and at least one cooling fin extending outward from the outer surface, and orienting the at least one cooling tube such that the at least one cooling fin is in flow communication within a syngas flow passage defined in the syngas cooler, wherein the cooling fin facilitates enhancing heat transfer between fluid flowing in the at least one cooling tube and a syngas flow.