DEVICE FOR RECOVERING SODIUM CHEMICALS FROM GREEN LIQUOR AND FLUE GASES

摘要

A device for recovering chemicals from flue gases and green liquor obtained from burning the waste liquor of sodium based pulping processes, which device comprises a precarbonation reactor, a H2S-stripping column, a carbonation reactor, a washing tower for flue gases and a cooling tower for washed flue gases and means for feeding flue gases into the washing tower, from the washing tower into the cooling tower and from the cooling tower into the carbonation reactor and the precarbonation reactor and for feeding flue gases out of the precarbonation reactor and the carbonation reactor, means for feeding green liquor into the precarbonation reactor, for leading solution containing sodium bisulfide from the precarbonation reactor into the stripping column and for discharging the solution containing sodium carbonate and sodium bicarbonate from the stripping column means for feeding transfer gas into the stripping column and for discharging gaseous hydrogen sulphide from the stripping column, means for feeding cooling water into the cooling tower and for discharging warm water therefrom, means for feeding the solution containing sodium carbonate and sodium bicarbonate into the carbonation reactor and thereafter into the stripping column, and means for feeding the solution containing sodium carbonate and sodium bicarbonate into the washing tower and for discharging the sodium sulfite solution therefrom, at least the carbonation reactor, the cooling tower and the washing tower being arranged on top of each other in the same column which is provided with trays so that the means for feeding flue gases from the washing tower into the cooling tower and further into the carbonation reactor are openings made in the trays to allow the washed flue gases to rise from the washing tower into the cooling tower above it and further into the carbonation reactor above the cooling tower, the means for feeding flue gases into the washing tower comprising common blower for blowing flue gases through washing tower, cooling tower, carbonation reactor and precarbonation reactor and the means for discharging the solution containing sodium carbonate and sodium bicarbonate from the stripping column being connected with means for feeding this solution directly into the carbonation reactor and the washing tower.