Patent ID: 6840199

Claim:
A process for heating steam, comprising: (a) obtaining steam by indirect heat exchange between liquid water and a hot gas, said hot gas comprises fouling causing compounds, by flowing said hot gas through the tube side of a tube bundle to yield a partly cooled hot gas; (b) heating the steam obtained in step (a) by indirect heat exchange with the partly cooled hot gas obtained in step (a) by flowing the partly cooled hot gas through the tube side of a shell-tube heat exchanger to yield a cooled hot gas; (c) adding an amount of additional water to the steam obtained in step (a) prior to or during heating the steam in step (b); and (d) controlling the temperature of the cooled hot gas by increasing over time, and as the tube side of said tube bundle and the tube side of said shell tube-heat exchanger become fouled, the amount of additional water added in adding step (c).