Improved low-temperature Claus sulfur recovery method

A sulphur recovery process method relates to the process sulphur recovery device technique field, wherein the invention mixes sour gas containing sulphur with air inside a main combustion furnace to complete Claus reaction; moreover, the process gas of the first tube pass of an exhaust heat boiler is used as reheating heat source. The invention is provided with a gas/gas heat exchanger, wherein the heat of the process gas of the first tube pass of the exhaust heat boiler of a sulphur recovery device or the 600 DEG C flue gas inside the outlet flue of an incinerator is used as regenerating heat source for follow-up reactor; a second, a third and a fourth stage of reactors and a third, fourth and fifth stage of sulphur condensation coolers are under programmed control by switching valves; during each switching cycle, two bed reactor are in low temperature adsorption state with one bed reactor undergoes a plurality of phases including gradual warming-up, stable regeneration, gradual pre-cooling and stable cooling. The method realizes pre-cooling of the reactor; when one reactor completely transits to low temperature adsorption state after regeneration, the catalyst arranged inside the next to-be-regenerated reactor reaches adsorption saturation and switches to generation state; moreover, both bed reactors of the invention are in the state of low temperature adsorption, thereby effectively avoiding fluctuation of sulphur recovery rate during switching so as to improve total sulphur recovery rate.