Filtration of biomass boiler flue gas
PROBLEMS OF BIOMASS BOILER FLUE GAS FILTRATION PROCESS
Dedusting and filtration of flue gases from a coal or biomass boiler is a very important topic in view of the increasingly stringent requirements for the discharge of particulate matter into the air. The majority of biomass boilers in operation, mostly of older date of manufacture, are equipped with cyclone separators or multicyclones only. These technologies for capturing ash from the flue gas do not achieve the required separation efficiency and the boilers exceed the permitted emissions of VOCs. Flue gas dedusting from biomass boilers is specific to the high occurrence of soot in the form of unburnt particles of sawdust, bark or wood chips.
Dedusting of large wood chip boilers is preferably solved by electrostatic filters, for smaller boilers with an output of 300 kW to about 2 MW it is costly to purchase an electrostatic filter and therefore dusting is solved by mechanical filters. However, mechanical fabric filters are completely out of the question after previous applications for dedusting of biomass boilers, as they are very susceptible to burning of the filter media, despite the use of special high temperature fabrics. For the dedusting of smaller biomass boilers we manufacture and install filter units with ceramic filter media. These G&G Ceramic JET filters are flame-resistant with resistance up to 900°C.