(US5330727-A)      An appts. comprises: a confirmed quantity of oxidn. catalyst forming an inlet and outlet portion; a mechanism for controlling the temp. of the inlet portion to above its threshold temp. and the outlet portion to below that temp.; and a mechanism for introducing gaseous oxygen to the inlet portion.    Pref. the mechanism for controlling temp. of the inlet is capable of maintaining 320 deg.F and comprises a cooling mechanism between the inlet and outlets.    USE/ADVANTAGE -   Used for reducing carbon monoxide concn. in a gaseous medium. Has a simplified structure.    (EP873967-A2)      Redn. of CO levels in a gaseous mixt. contg. at least hydrogen comprises: (a) prepn. of inlet and outlet portions of Co oxidising catalyst; (b) passing the gaseous mixt. through the catalyst portions from inlet to outlet; (c) introducing 02 into the inlet catalyst portion and (d) controlling the temp. to promote an exothermic reaction by maintaining the inlet temp. above the min. reaction threshold temp. and the outlet temp. below this temp. The reaction temp. is pref. kept considerably above the threshold temp. more pref. at 320 deg.F. At least two separate catalyst beds are used and the controlling step is carried out by cooling the gases between beds by removing heat. Oxygen can be added to the gaseous mixt. prior to passing into the catalyst beds. The outlet catalyst portion may be subdivided into a number of beds and the quantity of gas to be treated determined and then the gas is directed only to sufficient beds to achieve a flow rate high enough to prevent significant reverse shift of CO2 to CO.    USE/ADVANTAGE -   The method is used to treat gases generally, partic. removal of CO by oxidn. to CO2. The method gives lwoer final CO levels than previous methods and prevents reverse shift of CO2 to CO (claimed).    CO    (EP631564-B1)      Redn. of CO levels in a gaseous mixt. contg. at least hydrogen comprises: (a) prepn. of inlet and outlet portions of Co oxidising catalyst; (b) passing the gaseous mixt. through the catalyst portions from inlet to outlet; (c) introducing 02 into the inlet catalyst portion and (d) controlling the temp. to promote an exothermic reaction by maintaining the inlet temp. above the min. reaction threshold temp. and the outlet temp. below this temp. The reaction temp. is pref. kept considerably above the threshold temp. more pref. at 320 deg.F. At least two separate catalyst beds are used and the controlling step is carried out by cooling the gases between beds by removing heat. Oxygen can be added to the gaseous mixt. prior to passing into the catalyst beds. The outlet catalyst portion may be subdivided into a number of beds and the quantity of gas to be treated determined and then the gas is directed only to sufficient beds to achieve a flow rate high enough to prevent significant reverse shift of CO2 to CO.    USE/ADVANTAGE -   The method is used to treat gases generally, partic. removal of CO by oxidn. to CO2. The method gives lwoer final CO levels than previous methods and prevents reverse shift of CO2 to CO (claimed).    CO