Presented are processes for the beneficial conversion of CO.sub.2 and other environmentally destructive compounds to their constituent parts by the application of thermal plasma containing activated species whereby the interaction of the plasma with the compounds and reactions of CO.sub.2 and H.sub.2 generate more environmentally friendly compounds comprising in part oxygen and hydrogen. The thermal plasma may be vibro-shear plasma generated by the superheating of either steam, gas or a combination of both.

Presented are processes for the beneficial conversion of CO.sub.2 and other environmentally destructive compounds to their constituent parts by the application of thermal plasma containing activated species whereby the interaction of the plasma with the compounds and reactions of CO.sub.2 and H.sub.2 generate more environmentally friendly compounds comprising in part oxygen and hydrogen. The thermal plasma may be vibro-shear plasma generated by the superheating of either steam, gas or a combination of both.

A superheated-steam generating method that can quickly generate superheated steam and can prevent the superheated steam from reaching an excessively high temperature is disclosed. The superheated-steam generating method includes: determining a heater-temperature command value for minimizing a temperature difference within a first heater-temperature allowable range set for a first time segment; increasing the first heater-temperature allowable range by a predetermined upward shift amount to determine a second heater-temperature allowable range when the measured value of the temperature of the steam in the first time segment is smaller than the target temperature of the superheated steam and the temperature difference is larger than a first threshold value; and determining the heater-temperature command value for minimizing the temperature difference within the second heater-temperature allowable range set for a second time segment.

A superheated-steam generating method that can quickly generate superheated steam and can prevent the superheated steam from reaching an excessively high temperature is disclosed. The superheated-steam generating method includes: determining a heater-temperature command value for minimizing a temperature difference within a first heater-temperature allowable range set for a first time segment; increasing the first heater-temperature allowable range by a predetermined upward shift amount to determine a second heater-temperature allowable range when the measured value of the temperature of the steam in the first time segment is smaller than the target temperature of the superheated steam and the temperature difference is larger than a first threshold value; and determining the heater-temperature command value for minimizing the temperature difference within the second heater-temperature allowable range set for a second time segment.