Acid gas fired reheater control Operating as close as possible to the stoichiometric air-to-fuel ratio is advised for acid gas fired reheaters

摘要

Modified Claus based sulphur recovery units(SRUs)require successive cooling and reheating of the process gas stream as it passes through several catalytic converter stages.Between each converter,the gas is cooled to condense and remove elemental sulphur,then reheated to allow production of additional elemental sulphur in the next stage.Figure 1 shows a typical three-converter configuration.There are several common methods to reheat the stream including indirect steam heat,electric heaters,hot oil,gas/gas,and direct-fired reheaters.This article focuses on direct-fired reheaters which use some of the SRU's acid gas feed as fuel.Acid gas fired reheaters(AGFR)are burners positioned between the sulphur condenser and the next converter bed.The hot combustion gases from the burner are mixed with the main process stream in order to heat it to the desired converter temperature.