IT1116324B - Sulphur dioxide reduction with gaseous reducer - using split streams and alternating flow cycles to control temperature - Google Patents

Abstract

in gas streams is continuously reduced using H2, CO or a 1-4C hydrocarbon gas by (a) mixing the stream with 10-95% of the reducer gas and feeding 60-100% of the resulting mixt. to a first catalytic reactor at 850 degrees - 2400 degrees F. forming a stream of SO2, H2S and S (b) mixing this with the remaining reducer and remaining initial mixt. and passing 10-80% of the resultant mixt. to a second catalytic reactor, and passing the balance to a third operating in parallel, heat being absorbed in the third reactor to reduce the exiting gas stream temp. to 500 degrees-1000 degrees F, (c) periodically reversing the flow in the first and third reactors to subject them to alternate heat absorbing and desorbing cycles, the flow in the second reactor being maintained constantly in the same direction, and (d) maintaining the second and third reactor inlet temps. at 800 degrees-1800 degrees F by varying the amt. of the initial gas mixt. which bypasses the first reactor, during the alternating heat absorbing cycles. Method is esp. suited to treatment of gas streams having high SO2 concn. pref. 30-100% such as may be obtd. in a regenerative O2 absorption process. Close temp. control is achieved thus permitting efficient SO2 reduction.