Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
308 words
A process of purifying flue gases or other contaminated humid exhaust gases which contain SO 3 , characterized in that (a) the flue gas is cooled by an indirect heat exchange in a heat exchanger to a temperature below the dew point temperature of sulfuric acid, (b) the cooled gas is cooled further to about 75° to 92° C. in an SO 3 condenser by means of dilute sulfuric acid, which is sprayed to flow in a countercurrent to the gas, whereby dilute sulfuric acid having a predetermined concentration is condensed, (c) the gas leaving the SO 3 condenser is scrubbed and cooled to a temperature from 40° to 55° C. in a fine scrubber by a treatment with a sprayed aqueous sulfuric acid liquor capable of absorbing HC1 and HF, (d) the gas leaving the fine scrubber is reheated to a temperature of about 80° to 105° C. in a reheater by a treatment with sprayed dilute sulfuric acid from the SO 3 condenser, (e) the gas from which SO 3 has been condensed is passed through a filter, (f) dilute sulfuric acid leaving the reheater is sprayed into the SO 3 condenser, (g) the temperature of the gas in step (d) is so selected that the water absorbed in step (c) is not condensed but remains in the gaseous effluent, (h) the exit temperature of the gas in step (a) is approximately 120° to 157° C. so that the temperature of the dilute sulfuric acid obtained in step (b) is approximately the same as the temperature of the gas in step (d), and (i) the rate at which dilute sulfuric acid is sprayed in step (d) is so adjusted that the dilute sulfuric acid withdrawn in step (d) is at a temperature which approximately corresponds to the required exit temperature of the gas in step (b).
Claim 2
Dependent Claim
308 words
A process of purifying flue gases or other contaminated humid exhaust gases which contain SO 3 , characterized in that (a) the flue gas is cooled by an indirect heat exchange in a heat exchanger to a temperature below the dew point temperature of sulfuric acid, (b) the cooled gas is cooled further to about 75° to 92° C. in an SO 3 condenser by means of dilute sulfuric acid, which is sprayed to flow in a countercurrent to the gas, whereby dilute sulfuric acid having a predetermined concentration is condensed, (c) the gas leaving the SO 3 condenser is scrubbed and cooled to a temperature from 40° to 55° C. in a fine scrubber by a treatment with a sprayed aqueous sulfuric acid liquor capable of absorbing HC1 and HF, (d) the gas leaving the fine scrubber is reheated to a temperature of about 80° to 105° C. in a reheater by a treatment with sprayed dilute sulfuric acid from the SO 3 condenser, (e) the gas from which SO 3 has been condensed is passed through a filter, (f) dilute sulfuric acid leaving the reheater is sprayed into the SO 3 condenser, (g) the temperature of the gas in step (d) is so selected that the water absorbed in step (c) is not condensed but remains in the gaseous effluent, (h) the exit temperature of the gas in step (a) is approximately 120° to 157° C. so that the temperature of the dilute sulfuric acid obtained in step (b) is approximately the same as the temperature of the gas in step (d), and (i) the rate at which dilute sulfuric acid is sprayed in step (d) is so adjusted that the dilute sulfuric acid withdrawn in step (d) is at a temperature which approximately corresponds to the required exit temperature of the gas in step (b).
Claim 3
Dependent Claim
22 words
A process according to claim 1, characterized in that the dilute sulfuric acid has a concentration of 60 to 80% by weight.
Claim 4
Dependent Claim
33 words
A process according to claim 1, characterized in that the aqueous liquor which is sprayed in the fine scrubber also contains H 2 O 2 or H 2 S 2 O 8 .
Claim 5
Dependent Claim
29 words
A process according to claim 1, characterized in that the aqueous liquor which is sprayed in the fine scrubber is recirculated and is cooled by an indirect heat exchange.
Claim 6
Dependent Claim
25 words
A process according to claim 1, characterized in that the temperature of the gas leaving the reheater is increased by an admixing of hot gases.
Claim 7
Dependent Claim
34 words
A process according to claim 1, characterized in that the temperature of the dilute sulfuric acid which is fed from the SO 3 condenser to the reheater is increased by an indirect heat exchange.
Claim 8
Dependent Claim
50 words
A process according to claim 1, wherein in (b) the predetermined temperature is about 92° C., (d) the predetermined temperature is about 105° C., (h) the exit temperature of the gas in step (a) is about 157° C., and (i) the temperature of the withdrawn acid is about 92° C.
Claim 9
Dependent Claim
50 words
A process according to claim 1, wherein in (b) the predetermined temperature is about 75° C., (d) the predetermined temperature is about 80° C., (h) the exit temperature of the gas in step (a) is about 120° C., and (i) the temperature of the withdrawn acid is about 75° C.