Removal of undesired gaseous components from hot waste gases

In a process for removing undesired gaseous components from hot combustion gases by scrubbing with a regenerable absorbent, the undesired gaseous components being passed through dessicators prior to removal from the system, and the scrubbed combustion gases being removed through an exhaust stack,

• the improvement comprising:
• conducting the scrubbing with a liquid physical absorbent at a temperature less than 0.degree. C. and supplying the required cooling of the scrubbing process by means of an absorption-type refrigeration unit, cooling the combustion gases prior to scrubbing, in indirect heat exchange with gas streams to be heated, the indirect heat exchange being performed in an upper temperature range and a lower temperature range, and using air as said gas stream to be heated in the upper temperature range of the indirect heat exchange, resultant heated air being used in part as (a) preheated air of combustion, in part as (b) an energy source for the operation of the absorption-type refrigeration unit, in part as (c) an admixture to the purified combustion gases for increasing the temperature of the purified combustion gas and thus, the draft in the exhaust stack of the system, and for lowering the dew point of water in the flue gas, or in part as (d) a purging gas for regenerating the dessicators arranged for having the stream of products removed from the regenerated absorbent pass therethrough before removal from the system.