NOWADAYS, SULFUR IN HYDROCARBONS AS A H2S, BE RECOVERED BY VARIOUS PROCESSING. SOUTH PARS GAS COMPLEX’S REFINERIES USE CLAUS METHOD TO RECOVERY OF SULFUR. IN SULFUR RECOVERY UNITS, USING OF STEAM TRACING AND JACKETING FOR PREVENTING OF LINE AND VALVE CHOKING IS NECESSARY. BECAUSE MELTING SULFUR INSIDE THE LINES AND OTHER EQUIPMENTS DUE TO COOLING, MAY BE SOLD AND CAUSE A LINES CHOCKING. SO IN THIS PAPER, THE OPTIMUM STEAM TEMPERATURE OF THE TRACING AND JACKETING WAS STUDIED.