Main renewable energy source used in France, the wood-energy shows several advantages: abundant local resource, employment creation and carbon neutral emission. However, its combustion releases different pollutants such as particle matter or nitrogen oxides which can, during some period of the year, contribute significantly at the atmospheric pollution. This pollution has a serious impact on the human health and the environment (climate impact, water and soil pollution). In order to limit these impacts, these emissions are regulated, in particular since January 2014 through the Directive 2010/75/UE. This Directive gives the objectives for the industrial emissions which must be reduced. However, for the small plants (< 20 MWth), the emission limit values are less strict or non-existent for low power plant (< 2 MWth). In the case of the low power plants (< 2 MWth), there is only standards that allow to classify the different plants in more or less polluting categories. Considering the increasing of biomass-energy and this impact on the environment, the directive will be extended on smaller biomass boiler (< 4 MWth). This scale of plants are small, it is not possible for its to equip oneself with a gas treatment which is too complex. For this reason, it is necessary to develop integrated technologies.
Soots are carbonaceous aggregates with a size from 10 to 100 nm in aerodynamic diameter. They are emitted when the combustion is uncompleted, which are mainly due to combustion conditions poor in O2. At the exhaust of combustion room, emitted particles are generally trapped by two different devices, inertial filtration (cyclone(s)) for the largest (PM10) and then, porous filter media for the smallest (PM2.5). There are several types of filter media, as bag filter, moving or fixed bed granular filter and rigid filter, which of various nature in function of their composition (ceramic, metallic), structure (fibrous, sintered, etc.) and geometry (candle, disc, etc.).
The most widely used process for removing of only NOx is the Selective Catalytic Reduction (SCR) over V2O5-WO3 (MoO3)/TiO2 with NH3, as reducing agent, and in excess of O2. However, this SCR unit has to be located at the upstream particles filtration system, because it’s efficient at a temperature range of 300°C to 400°C, and this brings such problem, as the deposition of dust on catalyst. Several studies have been performed over transition metals oxide from Mn, Fe, Cu, Co and Ni supported on high specific surface materials in order to reduce NOx at lower temperature (< 300°C).
The CORTEA F3 project of which the aim is to develop a functionalized sintered filter to remove simultaneously soots and NOx emitted from small-scale biomass boiler address this issue. The filter media develop in this study is a...
Session: G15 - Hot Gas Cleaning
Day: 15 March 2018
Time: 10:45 - 12:00 h