One of the main causes of acid rain and also of other environmental problems such as photochemical air pollution and depletion of the stratospheric ozone layer arises from the anthropogenic emission of NOx. This proposal aims at developing nanocomposite materials for the Selective Catalytic Reducation (SCR) of NOx to N2 in the presence of excess O2 with hydrocarbons or oxygenates as reductants, using NO2 as an intermediate in the reaction. The nanocomposite catalysts will be designed to bring about separately some of the various reactions involved in the SCR process using a single catalytic bed. The catalyst will be constructed in such a way thant an inner layer of the materia which will be inaccessible to the reductant oxidises the NOx mixture to NO2, after which the surface layer (which traps the reductant and prevents it from reacting the centre of the particle) reacts the NO2 with the reducing agent to form N2.
This procedure is expected to improve the activity and selectivity of the catalyst formulations for the SCR of NOx over a broad temperature range by limiting the extent of the oxidation of the reductant by the oxygen of the flue gas. Another geometry using a porous-wall reactor concept in which oxidation and reduction catalysts are on opposite sides of a porous tube will also be considered. The possibility of using two consecutive catalyc beds will also be examined to give comparisons of the effectiveness and the economic aspects of the various systems. End-user applications include most processes involving air-combustion of fuel which requires emission contrl, i.e. ranging from power plants to car technologies. Two particular applications will be targeted here: the removal of NOx formed during the regeneration of the FCC catalysts in FCC plants and the removal of NOx from the blanket gases generated with gas motors for use in green-houses. With a view to developing an integrated control technology for the former application, the modification of the current FCC catalyst will be carried to favour the formation of NO2 which will subsequently react with carbonaceous deposits within the regenerator.
Funding SchemeCSC - Cost-sharing contracts
7500 AE Enschede
RG6 6AD Reading, Berkshire