Recovery of sulphur from gases contg. sulphur cpds. - by treating gas with polybasic organic acid

摘要

Hydrogen sulphide is removed from a gas by treating it with an aq. soln. of a polybasic organic acid having a dissociation constant of 10-2 - 10-5, the soln. being buffered with a base. The molar ratio between H2S and SO2 in the gas is =2:1 and it is injected into the soln. which is at pH 2-6 (3.3-3.9), at 10-100 degrees C forming solid sulphur which is removed by a current of the soln. from the reaction chamber. Gas contg. SO2 and having the soln. is heated to 700-1000 degrees C to transform S-contg. cpds. into SO2, and the gas is recycled. The rest of gas leaving the soln. is treated with a second absorption step with the soln. having the reaction chamber to remove the last traces of S. The process enables gas mixtures richer in H2S than cleavable by the Claus process to be purged of sulphurous gases.