Abstract: Apparatus for treating gases produced from the conversion of coal, e.g., from carbonization of coal, to remove the undesirable constituents thereof is disclosed. The method involves passing the hot raw gases from the coal conversation process over a coke bed at a temperature of more than 1100.degree. K. The coke bed is located in the coal gasification reactor and is provided with an ordinary air supply. The subject method achieves a significant reduction in undesirable constituents in the gas and eliminates the need for auxiliary gas treatment systems, oxygen production systems and the like.

Abstract: Exhaust gases containing residual nitric oxide constituents from a processing operation are maintained at an elevated pressure, heated to from 260.degree. C. to 340.degree. C. in a separate heat exchanger, and subjected to multi-stage catalytic reduction with ammonia to produce purified exhaust gases. The pressure of the thus purified exhaust gases is then relieved in an expansion turbine.

Abstract: Exhaust gases containing residual nitric oxide constituents from a processing operation are maintained at an elevated pressure, heated to from 260.degree. to 340.degree. C., and subjected to catalytic reduction with ammonia to produce purified exhaust gases. The pressure of the thus purified exhaust gases is then relieved in an expansion turbine.