Abstract 1. A PROCESS FOR PRODUCING GYPSUM FROM COMBUSTION EXHAUST GAS WHICH COMPRISES STEPS OF: A. INTRODUCING HIGH TEMPERATURE COMBUSITON EXHAUST GAS CONTAINING THEREIN SULFUR DIOXIDE AND FINE SOLID PARTICLES INTO AN ABSORBING DEVICE TO LOWER THE TEMPERATURE THEREOF DOWN TO APPROXIMATELY 180*C. TO 150*C., SUBSEQUENTLY CONTACTING THE SAME WITH WATER TO FURTHER LOWER THE GAS TEMPERATURE TO A RANGE OF FROM 95*C. TO 80*C. SIMULTANEOUSLY ADJUSTINGG RELATIVE HUMIDITY THEREOF TO A RANGE OF FROM 15% TO 60% AND THEREBY REMOVING A SUBSTANTIAL PART OF SAID FINE PARTICLES; B. CONTACTING THE THUS TEMPERATURE- AND MOISTURE-ADJUSTED GAS WITH SOLUTION OF ALKALI SULFITE SELECTED FROM THE GROUP CONSISTING OF SODIUM SULFITE AND POTASSIUM SULFITE TO ABSORB AND FIX SULFUR DIOXIDE IN SAID EXHAUST GAS IN THE FORM OF SOLUTION OF ACIDIC ALKALI SULFITE; C. CAUSING SAID ALKALI SULFITE SOLUTION TO REACT WITH A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE AND CALCIUM HYDROXIDE TO PRODUCE CRYSTALS OF CALCIUM SULFITE THEREFROM; D. SEPARATING SAID CALCIUM SULFITE FROM SAID ALKALI SULFITE SOLUTION, AND WASHING THE FORMER WITH WATER; AND E. MAKING SAID CALCIUM SULFITE INTO A SLURRY, AND CONTACTING THE SAME WITH A SMALL QUANTITY OF AIR TO OXIDIZE THE SAME TO PRODUCE GYPSUM; BOTH ALKALI SULFITE SOLUTION AND WATER USED FOR WASHING CALCIUM SULFITE AS SEPARATED IN THE STEP D. BEING RECYCLED FOR FURTHER USE IN ABSORBING AND FIXING OF SULFUR DIOXIDE IN THE EXHAUST GAS IN THE STEPS B., AND WATER MIXED INTO THE ALKALI SULFITE SOLUTION IN STEPS A., C., AND D. BEING EVAPORATED IN STEP B. TO BALANCE THE WATER CONTENT IN THE REACTION SYSTEM.
A PROCESS FOR PRODUCING GYPSUM FROM COMBUSTION EXHAUST GAS WHICH COMPRISES STEPS OF: A. INTRODUCING HIGH TEMPERATURE COMBUSITON EXHAUST GAS CONTAINING THEREIN SULFUR DIOXIDE AND FINE SOLID PARTICLES INTO AN ABSORBING DEVICE TO LOWER THE TEMPERATURE THEREOF DOWN TO APPROXIMATELY 180*C. TO 150*C., SUBSEQUENTLY CONTACTING THE SAME WITH WATER TO FURTHER LOWER THE GAS TEMPERATURE TO A RANGE OF FROM 95*C. TO 80*C. SIMULTANEOUSLY ADJUSTINGG RELATIVE HUMIDITY THEREOF TO A RANGE OF FROM 15% TO 60% AND THEREBY REMOVING A SUBSTANTIAL PART OF SAID FINE PARTICLES; B. CONTACTING THE THUS TEMPERATURE- AND MOISTURE-ADJUSTED GAS WITH SOLUTION OF ALKALI SULFITE SELECTED FROM THE GROUP CONSISTING OF SODIUM SULFITE AND POTASSIUM SULFITE TO ABSORB AND FIX SULFUR DIOXIDE IN SAID EXHAUST GAS IN THE FORM OF SOLUTION OF ACIDIC ALKALI SULFITE; C. CAUSING SAID ALKALI SULFITE SOLUTION TO REACT WITH A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE AND CALCIUM HYDROXIDE TO PRODUCE CRYSTALS OF CALCIUM SULFITE THEREFROM; D. SEPARATING SAID CALCIUM SULFITE FROM SAID ALKALI SULFITE SOLUTION, AND WASHING THE FORMER WITH WATER; AND E. MAKING SAID CALCIUM SULFITE INTO A SLURRY, AND CONTACTING THE SAME WITH A SMALL QUANTITY OF AIR TO OXIDIZE THE SAME TO PRODUCE GYPSUM; BOTH ALKALI SULFITE SOLUTION AND WATER USED FOR WASHING CALCIUM SULFITE AS SEPARATED IN THE STEP D. BEING RECYCLED FOR FURTHER USE IN ABSORBING AND FIXING OF SULFUR DIOXIDE IN THE EXHAUST GAS IN THE STEPS B., AND WATER MIXED INTO THE ALKALI SULFITE SOLUTION IN STEPS A., C., AND D. BEING EVAPORATED IN STEP B. TO BALANCE THE WATER CONTENT IN THE REACTION SYSTEM.
Claim 2
Dependent Claim
265 words
A PROCESS FOR PRODUCING GYPSUM FROM COMBUSTION EXHAUST GAS WHICH COMPRISES STEPS OF: A. INTRODUCING HIGH TEMPERATURE COMBUSITON EXHAUST GAS CONTAINING THEREIN SULFUR DIOXIDE AND FINE SOLID PARTICLES INTO AN ABSORBING DEVICE TO LOWER THE TEMPERATURE THEREOF DOWN TO APPROXIMATELY 180*C. TO 150*C., SUBSEQUENTLY CONTACTING THE SAME WITH WATER TO FURTHER LOWER THE GAS TEMPERATURE TO A RANGE OF FROM 95*C. TO 80*C. SIMULTANEOUSLY ADJUSTINGG RELATIVE HUMIDITY THEREOF TO A RANGE OF FROM 15% TO 60% AND THEREBY REMOVING A SUBSTANTIAL PART OF SAID FINE PARTICLES; B. CONTACTING THE THUS TEMPERATURE- AND MOISTURE-ADJUSTED GAS WITH SOLUTION OF ALKALI SULFITE SELECTED FROM THE GROUP CONSISTING OF SODIUM SULFITE AND POTASSIUM SULFITE TO ABSORB AND FIX SULFUR DIOXIDE IN SAID EXHAUST GAS IN THE FORM OF SOLUTION OF ACIDIC ALKALI SULFITE; C. CAUSING SAID ALKALI SULFITE SOLUTION TO REACT WITH A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE AND CALCIUM HYDROXIDE TO PRODUCE CRYSTALS OF CALCIUM SULFITE THEREFROM; D. SEPARATING SAID CALCIUM SULFITE FROM SAID ALKALI SULFITE SOLUTION, AND WASHING THE FORMER WITH WATER; AND E. MAKING SAID CALCIUM SULFITE INTO A SLURRY, AND CONTACTING THE SAME WITH A SMALL QUANTITY OF AIR TO OXIDIZE THE SAME TO PRODUCE GYPSUM; BOTH ALKALI SULFITE SOLUTION AND WATER USED FOR WASHING CALCIUM SULFITE AS SEPARATED IN THE STEP D. BEING RECYCLED FOR FURTHER USE IN ABSORBING AND FIXING OF SULFUR DIOXIDE IN THE EXHAUST GAS IN THE STEPS B., AND WATER MIXED INTO THE ALKALI SULFITE SOLUTION IN STEPS A., C., AND D. BEING EVAPORATED IN STEP B. TO BALANCE THE WATER CONTENT IN THE REACTION SYSTEM.