Abstract: A compact catalytic reactor defines a multiplicity of first and second flow channels arranged alternately, the first flow channels being no more than 10 mm deep and providing flow paths for combustible reactants, and containing a catalyst structure (20) to catalyze combustion of the reactants, and having at least one inlet for at least one of the reactants. The first flow channel also includes an insert (40 or 60) adjacent to each inlet, this insert not being catalytic to the combustion reaction; the insert may define gaps which are narrower than the maximum gap size for preventing flame propagation.

Abstract: A microwave plasma generator including field-enhancing electrodes consisting of opposed laminae (108,109) with a gap (110) between them orthogonal to the direction of propagation through the plasma generator of microwave radiation. Gas inlet (106) and outlet (107) ports are arranged so that a gaseous medium to be excited into the plasma state passes through the gap (110).

Abstract: A compact catalytic reactor defines a multiplicity of first and second flow channels arranged alternately, the first flow channels being no more than 10 mm deep and providing flow paths for combustible reactants, and containing a catalyst structure (20) to catalyse combustion of the reactants, and having at least one inlet for at least one of the reactants. The first flow channel also includes an insert (40 or 60) adjacent to each inlet, this insert not being catalytic to the combustion reaction; the insert may define gaps which are narrower than the maximum gap size for preventing flame propagation.

Abstract: A method and apparatus for removing nitrogen oxides from internal combustion engine exhaust emissions consisting of the operations of contacting the exhaust emissions with a non-thermal plasma (1) and a silver doped alumina catalyst (2) and then an indium-doped zeolite catalyst (3).

Abstract: A microwave plasma generator including field-enhancing electrodes consisting of opposed laminae (108,109) with a gap (110) between them orthogonal to the direction of propagation through the plasma generator of microwave radiation. Gas inlet (106) and outlet (107) ports are arranged so that a gaseous medium to be excited into the plasma state passes through the gap (110).

Abstract: A method and apparatus for removing nitrogen oxides from internal combustion engine exhaust emissions consisting of the operations of contacting the exhaust emissions with a non-thermal plasma (1) and a silver doped alumina catalyst (2) and then an indium-doped zeolite catalyst (3).

Abstract: A plasma enhanced gas reactor including a reaction chamber having a pair of field-enhancing electrodes each of which has an axial passage through it by one of which a reactant gas is admitted to the reaction chamber, and by the other of which reaction products are removed from the reaction chamber.

Abstract: An apparatus for detecting the presence of volatile substances in a gaseous medium, including apparatus for producing within a sensor chamber a localised electric field the energy density of which is sufficient to excite the gaseous medium to a plasma condition, and apparatus for detecting changes in a parameter of the plasma due to the presence of the volatile substances in the gaseous medium.