Catalytic ceramic candle filter (BisCat)

BisCat ceramic filters with an embedded catalyst matrix allow the removal of particulates, acidic gases, dioxins, mercury, VOC and NOx. The filter elements are chemically inert and corrosion resistant.

Gas cleaning in one step. In addition to treating particulate and acidic gases like in a conventional candle filter, the BisCat ceramic catalyst filters are enriched with a catalyst, providing effective NOx removal by using upfront ammonia injection and replacing a conventional selective catalyst reactor (SCR).

The BisCat filter solution is combining three process steps in one unit for advanced emission control:

• Dedusting
• Removal of acid components
• Reducing unburned hydrocarbon (THC) and NOx

The ceramic filter elements show very low dust emissions (< 2 mg/Nm³) and are thermally stable under high operating temperatures. No cooling of flue gases are required and no thermal heat energy is wasted when implementing them. 

Filter elements are cleaned online during operation through separate, compressed air jet pulses. The filter elements are placed in a single or multi-compartment housing to handle large volumetric flow rates. This construction technique allows for maintenance of a single module while others continue to operate, without interrupting the process altogether.

The injection of lime-based reagents allows for control of inorganic gaseous emissions like HF, HCl, and SOx. The rigid candle structure enables surface filtration and forms a first layer of reactive dust for absorption processes.