Seeley, Andrew J.; Price, Duncan M.; Stanton, Gareth D.; Ostertag-Hill, Christopher A.; Alcock, Laura; Radiar, Alageswaren R. B.; Abatement. GB Patent Application 2,571,793 March 9 (2018)
A method comprises supplying an initial reaction zone of an abatement apparatus with non-stoichiometric amounts of initial reactants to perform an initial abatement reaction under non-stoichiometric conditions to produce a first reaction product at a concentration which is lower than a second reaction product; and supplying a subsequent reaction zone of the abatement apparatus with a subsequent reactant to perform a subsequent abatement reaction to lower the concentration of the second reaction product. Supplying the initial reaction zone may comprise providing an excess of the initial reactant. The initial reactant may provide a reducing or oxidising environment, and the initial reactant can comprise a fuel and an oxidant. The second initial reactant can also comprise another of an oxidant and a fuel. The subsequent abatement reaction may react a third reactant with said second reaction product, and the third reactant may comprise oxygen, ozone or peroxide. Supplying the third reactant may comprise providing an excess of hydrogen. The abatement reaction may be a combustion reaction, and the first reaction product may comprise NOx and the second reaction product may comprise CO. The initial reaction zone may be hotter than the subsequent reaction zone.