Patent ID: 8287815

Claim:
A system for preheating a vessel including a high-temperature fluid inlet throat, an outer shell, and a purge volume defined therebetween, said system comprising: a throat cooling tube assembly positioned between the vessel inlet throat and the purge volume, said throat cooling tube assembly comprises horizontally coiled tubing circumscribing the inlet throat; a first heat exchanger coupled in flow communication to said throat cooling tube assembly, said first heat exchanger configured to transfer heat between a flow of sub-cooled cooling fluid channeled from said throat cooling tube assembly and a flow of purge fluid into the purge volume; a second heat exchanger coupled downstream of said first heat exchanger and upstream of said throat cooling tube assembly; and a steam drum coupled in flow communication with said first heat exchanger via a conduit, said throat cooling tube assembly is coupled in flow communication with at least one of said steam drum and said conduit, wherein said flow of cooling fluid channeled into and out of said cooling tube assembly and into at least one of said steam drum, said first heat exchanger, and said second heat exchanger is maintained sub-cooled and said flow of purge fluid into the purge volume is heated to facilitate reducing a thermal stress in the inlet throat and the outer shell.