The Hoval CF Biomass Filter is an optional bespoke engineered air filtration device designed
to remove air borne particles from the combustion gasses of biomass pellet heating boilers.
The unit is skid mounted and includes an integral induced draught fan sized to fit the range of
Hoval biomass pellet boilers
1
. The unit is suitable for both new and retrofit installations where
footprint allows. The control, efficiency and safety philosophy of the biomass boiler combustion
is integrated seamlessly into the CF Biomass Filter. The unit is available in various sizes and
dimensions suitable for boiler outputs from 50kW to 1200kW. The units can also be fitted
to other biomass pellet boilers. For guidance and details please contact Hoval’s Technical
Department.
The Hoval CF Biomass Filter is a compact unit comprising vertically arranged ceramic filter
elements cased in metal sheeting encompassing its own electronic controls and compressed
air fed self-cleaning technology. The base of the unit comprises a bin for collection and
removal of cleaned air borne particulate. The greater the output of the boiler the greater the
number of filter elements required to clean the particulates from the flue gas.
The unit is always situated downstream from the point of biomass combustion and cleans the
flue gasses effectively regardless of load or degradation of fuel quality. The filtration process
effectively removes up to 96% of air borne PM2.5 and PM10 combustion particulates.
The combustion gasses pass through the ceramic filter elements and are cleaned during this
process. Particulates and dust are collected on the surface of the ceramic filter that is then
cleaned, at pre-set timed intervals, by a controlled blast of compressed air
1
that dislodges the
collected particles causing them to fall downwards and collect in the ash bin. The ash bin can
then be safely emptied at controlled intervals.
The ceramic filter elements are designed to have an operational life of between 3-5 years
depending on the level of filtration in use. The elements are easily replaced by vertically
removing the existing elements from the unit and replacing with a new element. Accordingly it
is essential to locate the filter with a minimum of one metre headroom above the unit.
The unit has been independently performance tested by TÜV under both perfect and imperfect
combustion conditions with results that indicate post combustion particulate reduction to a
level of less than 5mg/m
3
.
Areas of Use:
Due to the excellent particulate filtration properties of the unit it is ideally suited to be used in
areas where ground level air particulate pollution is already high. The use of the CF Biomass
Filter in urban areas will negate the impact of additional air borne particulate from biomass
combustion used for space heating and generation of hot water.
• City centres and other high density urban population concentrations
• Locations with high levels of existing or planned road traffic
• Locations with high levels of existing or planned industrial activity
As a result of the filtration process where the CF Biomass Filter is fitted there is no need to
increase stack height for the purpose of particulate dispersion. However, all factors relating to
combustion need to be verified on a site by site basis.
The use of alternative abatement technology such as the larger cyclone technology (supplied
as standard with many biomass boilers – including the larger Hoval STU pellet boilers
will reduce the air borne particulate pollution in the PM10 category, but will not generally
remove significant quantities of the smaller PM2.5 particles. In rural areas where there is a
low background level of air pollution and only a seasonal heating load the use of cyclone
technology may be acceptable.
In all circumstances, however, the quality of fuel at point of combustion remains of paramount
importance to the operational performance, efficiency of the boiler and the level of air borne
particulates.
1 Compressed air supply by others.
Hoval CF Biomass Filter. Advanced air filtration for biomass heating.
Hoval CF 70 Biomass Filter
Ceramic filters in virgin state
Ceramic filters after cleaning process
Birds eye view of opened CF Biomass
Filter
CF Biomass Filter
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