14. Nuisance Bag Filter Design Pressure
In a cement plant nuisance bag filters are installed at all location of transfer points
and at other places where dust generation is high so that local environment can
be maintained dust emission free and also dust losses can be minimised and
collected in dust collector only and utilised in manufacturing process.
Normally in cement industry the nuisance bag filter pressure is designed up to
250 - 300 mmwg but during actual operation it is observed that the pressure
is normally measured around 100-150 mmwg only depending on the dust load and
air volume to be handled by bag filter.
Designing high pressure bag filters is leading in wastage of power on account of
all nuisance bag filters.
It is advisable to keep design pressure at 150 - 200 mmwg only which may turn
into savings of around 200-300 KW i.e. 0.5-1.0 kwh/t of clinker on account of all
nuisance bag filters of plant in totality, which will be a good opex savings on
continuous & sustainable basis. To design such low pressure if required the dust
collector size can be made bigger this may require higher initial capex but the opex
savings will huge and also economical in longer run and also the maintenance coat
of bag filter will be lesser.
We can design the NBF at 15% higher flow recommended over supplier flow as
we are installing the VFD for all dust collector flow can be controlled as per
requirement but pressure should be kept 150 mmwg only which may reduce
the operating power and opex accordingly.
It is also advisable to design venting lines of all NBF so the velocity should be as
minimum as possible which will reduce the pressure drop of circuit and also reduce
the dust loading of dust collector leading in increased efficiency of NBF.