GEA has developed high-temperature filters with ceramic elements that enable the removal of NOx, dioxins, mercury and VOC through an integrated catalyst matrix. BisCat ceramic catalyst filters are chemically inert and corrosion-resistant. This means that for many applications only one single system is required instead of three.
Particle separation takes place with the aid of filter elements made of mineral fibres, the so-called ceramic candle. These candles are well proven and very flexible to use even with regard to modifications of operating parameters, especially at high gas temperatures. No cooling of flue gases is required and no thermal heat energy is wasted. Filter elements are cleaned from separated dust online during operation by means of separate, compressed air jet pulses. The single or multi-sectional housings developed by GEA allow a maximum filter length of 6 m. This means that even large gas volume flows can be cleaned. The design of the system allows maintenance of the individual elements during operation.
By injecting lime-based reagents, inorganic pollutants such as HF, HCl, SOx can also be absorbed.
GEA has further developed the ceramic filter elements and enriched them with a catalyst. In addition to particles and acid gases, nitrogen oxides can thus be efficiently separated after prior injection of ammonia. This replaces the conventional selective catalytic reactor (SCR).
The GEA BisCat filter system thus combines the 3 process stages of dedusting, separation of acid components and reduction of total hydrocarbons (Total Hydrocarbons, THC) and nitrogen oxides (NOx) in one unit. Applications include the cement and glass industries, incinerators, refineries and roasters.