Method for removing hydrogen sulfide from sulfur-bearing industrial gases with claus-type reactors

Claim 1

In a method of desulfurizing a hydrogen sulfide and hydrogen containing fuel gas without exhausting any sulfur containing tail gas including: (a) contacting a hydrogen sulfide and hydrogen containing feed fuel gas with an absorbing solution to absorb substantially all hydrogen sulfide from said feed fuel gas and generate a substantially desulfurized fuel gas, (b) desorbing said hydrogen sulfide from said absorbing solution and passing said desorbed hydrogen sulfide to a Claus reaction zone together with an approximately stoichiometric amount of sulfur dioxide based upon the amount of hydrogen sulfide which is to be reacted with sulfur dioxide in said reaction zone to form elemental sulfur and water leaving a tail gas with sulfur components, the improvement comprising: (c) conducting a portion of a fuel gas of step (a) to a catalytic hydrogenation zone in a quantity sufficient to provide at least an amount of hydrogen to stoichiometrically react with any sulfur dioxide, carbonyl sulfide, carbon disulfide and elemental sulfur vapors contained in the tail gas from step (b), (d) conducting the tail gas from the reaction of sulfur dioxide with hydrogen sulfide in step (b) to the catalytic hydrogenation zone of step (c) and reacting sulfur dioxide, carbonyl sulfide, carbon disulfide and elemental sulfur vapors in said tail gas with the hydrogen in said fuel gas to form hydrogen sulfide plus additional amounts where appropriate of methane and water and form a hydrogenated tail gas, and (e) recycling said hydrogenated tail gas with no substantial sulfur content in a form other than hydrogen sulfide to contact said absorbing solution of step (a) simultaneously with said hydrogen sulfide and hydrogen containing feed fuel gas.