Patent ID: 6572835
Filing Date: 2003-06-03
Classification: C01B

Abstract:
A process for producing sulfur trioxide (SO3), said process comprising the steps of:providing a first gaseous mixture, consisting essentially of sulfur dioxide (SO2 and air, from a source for said mixture; flowing a stream containing said first gaseous mixture through a plurality of tubular channels each having upstream and downstream ends; providing each of said tubular channels with a single, uninterrupted conversion stage having upstream and downstream ends; providing said conversion stage with a catalyzing agent for catalyzing the conversion of SO2 to SO3; providing each of said tubular channels with an upstream channel portion, devoid of catalyzing agent, between the upstream end of the tubular channel and the upstream end of the conversion stage; conducting said first gaseous mixture from said source to said conversion stage without heating said first gaseous mixture between said source and said upstream end of said conversion stage; converting at least 95% of said SO2 in said first gaseous mixture to SO3, as said stream flows through said single conversion stage, to produce a second gaseous mixture consisting essentially of SO3 and air at the downstream end of said conversion stage; performing, in said single conversion stage, the totality of the conversion of SO2 to SO3; maintaining said gaseous oxide-containing stream in substantially continuous, uninterrupted contact with said catalyzing agent between the upstream and downstream ends of the conversion stage; cooling said gaseous oxide-containing stream by subjecting said stream to cooling air substantially continuously between the upstream end of the tubular channel and the downstream end of the conversion stage, without diluting said stream with said cooling air, while maintaining said uninterrupted contact between said stream and said catalyzing agent; generating heat as a result of said conversion; and providing said first gaseous mixture from said source with a gas temperature at the upstream end of the tubular channel that (a) requires cooling between said upstream end of the tubular channel and the upstream end of the conversion stage in order to initiate conversion in the conversion stage and (b), together with the heat generated by said conversion, requires said cooling by said cooling air substantially continuously between the upstream end of the tubular channel and the downstream end of the conversion stage to convert at least 95% of the SO2 in said first gaseous mixture to SO3 in said single conversion stage; all of said previously recited steps cooperating to convert at least 95% of said SO2 to SO3 in said single conversion stage, while employing said non-diluting cooling air as the fluid cooling medium for said gaseous-oxide containing stream.