Flue gas filtration of biomass boilers

Flue gas filtration of biomass boilers

Dedusting and filtration of flue gases from a coal or biomass boiler is a very important topic due to the increasingly stringent requirements for the discharge of solid pollutants into the air. Most of the operated biomass boilers, mostly of older production date, are equipped only with cyclone separators or multicyclones. These flue gas ash capture technologies do not achieve the required separation efficiency and the boilers thus exceed the permitted TZL emissions. Dust removal of flue gases from biomass boilers is specific to the large occurrence of non-burnt in the form of unburned particles of sawdust, bark, or wood chips.

Dedusting of large wood chip boilers is advantageous to solve with the help of electrostatic precipitators, for smaller boilers with an output from 300 kW to approx. 2 MW the acquisition of an electrostatic precipitator is expensive and therefore dedusting is solved by mechanical filters. However, after previous applications for dedusting biomass boilers, mechanical fabric filters are eliminated, as they are very prone to burning of the filter medium, despite the use of special high-temperature fabrics. For dedusting of smaller biomass boilers, we manufacture and install filter units with ceramic filter media. These G&G Ceramic JET filters are fire resistant with resistance up to 900 °C.
Flue gas filtration of biomass boilersFlue gas filtration of biomass boilers

Ceramic filters for small biomass boilers

The G&G Ceramic JET-B flue gas filters are designed for dedusting flue gases generated by the combustion of solid fuels in combustion sources. Thanks to their construction, the filter units are used for dedusting biomass combustion boilers. The basic characteristic of filtration devices is the resistance to hot particles and residues of unburned fuel which occur in the flue gases during the combustion of biomass. The flue gases entering the filter unit are directed to the lower part of the filter device by means of an internal partition so that the housing of the filter unit is evenly heated. The flue gas passes through the filter medium upwards into the clean filter chamber and then through the outlet opening to the flue gas fan. Ash collection takes place in the standard design into integrated ash tanks which the boiler operator periodically empties. For boilers in continuous operation, the filter units are to be equipped with an automatic ash removal system. At lower installation heights the removal of dust is solved by means of a movable bottom of the filter and then by a screw conveyor to the dustbin. The filtration device is thermally insulated over the entire casing and is equipped with an electric heating cable for tempering the filter housing and preventing condensation of flue gases at the moment of starting or stopping the boiler at a low flue gas temperature. The filtration equipment does not have to be equipped with a pyramidal dust hopper due to the lower installation dimensions for the possibility of installation directly into the boiler room.

Flue gas filtration of biomass boilers

Electrostatic filters for suction of large sources

We use electrostatic separators to dedust large combustion sources. In the electrostatic separators, dust particles are separated due to the action of an electric field. Electrically neutral dust particles are charged by negative electrodes when they enter the filter. After charging, the dust particles of the flue gas are attracted to the positive electrodes to which these particles adhere. The tapping system of the plates then ensures that the dust sediments are tapped and fall into the filter hopper from where they are transported to the container by means of screw conveyors. Electrostatic precipitators have a small operating pressure drop, which does not fluctuate depending on the amount of dust separated. The source of high voltage, 70 kV, is the filter itselfs transformer.

G&G filtration

Let's work together

If you are planning to implement a flue gas dedusting system from a coal or biomass boiler, we offer you cooperation in the design, production, and implementation of the exhaust technology. We will be glad if you contact us.