TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Apparatus: The converter comprises an air heater, a combustion chamber and a plasmatron connected to a microwave radiation source. The plasmatron comprises a plasma-catalytic chemical reactor containing a cylindrical H11-type microwave resonator (3) for producing a streaming pseudo-corona pulsed-periodic microwave discharge with a wavelength in the cm or dm range at atmospheric pressure. Pulse duration is 0.1-1 microsecond and discharge output pitch is 10-100. The combustion chamber is installed between the air heater and reactor, and it is connected to separate tubes for introducing the combusted fuel and non-combusted fuel/steam mixture into different regions of the chamber.Preferred Method:Pseudo-corona discharge is carried out at atmospheric pressure. The intensity of the pulsed microwave electric field inside the reactor is set below a disruptive level, discharge is initiated at the points of the corona components and the intensity of the microwave electric field is greater than 100 kV/cm, so that microwave energy takes less than 1 microsecond to reach the reactor wall. Microwave radiation is used with the following properties - pulse duration of 0.1-1 microsecond, discharge output pitch of 100-1000 and pulse potential level designed to generate a microwave electric field with an intensity greater than 100 kV/cm. The sum (Q) of the reactants and the mean microwave potential (W) are determined from an equation corresponding to the range of values for the specific energetic contribution of the plasma (Q/W), equivalent to 0.05-0.2 kVt.hour/nm3. The value for the specific energetic contribution of the plasma is not greater than 5-10 % of the magnitude of the energy content of the reactants at the working temperature of the process. Reactant temperature at the reactor entrance is 800-1500 K, the combusted fuel/non/combusted fuel ratio in the combustion chamber is 0.5-2:1 and the water/air and water/fuel molar ratios at the reactor inlet are 0.06-2.5:1 and 1-6:1 respectively. Alternatively, reactant temperature at the reactor entrance is 600-1100 K, the combusted fuel/non/combusted fuel ratio in the combustion chamber is 0.5-2:1 and the air/fuel molar ratio at the reactor inlet is 16-20:1.Preferred Embodiments: Microwave radiation is supplied to the resonator via a rectangular waveguide (7) formed by the resonator side wall or extending over the length of the resonator axis. The waveguide and resonator are connected to the excitation system via a communication element (6). The reactant inlet tube is formed by one of the two end reflectors in the resonator, and the reaction product exit system (4) comprises the second end reflector, or alternatively, the reactant inlet tube or reaction product exit system tube is formed by one of the end reflectors in the resonator and the excitation system is formed by the other end reflector. The rectangular waveguide length axis is separated from one of the end reflectors by a distance (L1) equivalent to various H11 type radiation half-wave longitudes in the cylindrical waveguide, and the choice of the resonator diameter (D) is based on the excitation condition in the final type of H11 wave and the resonator length (L) being equivalent to a value chosen from the H11 type radiation half-wave longitudes. The connection coefficient for the resonator is set below the conditions that ensure a sub-distinctive level for the microwave electric field intensity for the given reactor-resonator diameter. The array of pointed metal parts forming the corona components used to initiate the discharge are installed in regions of maximum electric field intensity in the resonator. The combustion chamber comprises two concentric supersonic tube system installed in succession with respect to the gas flow and connected with the reactant inlet tubes. The air heater comprises a heat exchanger.