| 摘要 |
<p>PURPOSE:To improve the SO2 recovery rate by adsorbing an SO2-contg. gas concentrated in a first-stage adsorption tower in a second-stage adsorption tower, then concurrently purging the gas, adsorbing the effluent gas again in the second adsorption tower, recovering the adsorbed SO2 by vacuum and then countercurrently restoring the pressure. CONSTITUTION:A gaseous starting material contg. <=40vol.% SO2 is compressed and introduced into a first-stage adsorption tower 6a packed with an adsorbent 5 to adsorb SO2, and the difficult-to-adsorb gas is discharged. A part of the discharged gas is returned to an adsorption tower 6b, countercurrently purged to desorb SO2, compressed and introduced into a second-stage adsorption tower 16a to adsorb SO2, and the difficult-to-adsorb gas is discharged. A concd. SO2-contg. gas is concurrently passed through a second-stage adsorption tower 16b after adsorption to purge the residual difficult-to-adsorb gas and returned to the second-stage adsorption tower 16a to adsorb SO2. The tower is then evacuated to desorb and recover SO2 and a concd. SO2-contg. gas is stored in a product holder 27. A part of the difficult-to-adsorb gas discharged from an adsorption tower 16c is introduced into an adsorption tower 16d to restore the pressure to atmospheric pressure, and the tower is prepared for the succeeding adsorption stage.</p> |
