Starting from a typical cement process flow chart, we have selected some process points in which the nuisance filters are necessary in order to allow a proper material handling. A comprehensive study and the deepl knowledge of the upstream equipment allow an efficient dedusting action and emission control by the filtering unit.
Data and configurations of these equipment are only for study purposes, real cases need may differ from the data showed.
Horizontal ball mills doesn’t use all the amount of hot gas coming form the kiln.
Some hot gas is by-passed and cooled down in towers where water is sprayed.
The raw materials enter the horizontal mill in coarse pieces and leave the grinding department as dust (raw meal).
Part of the production (dust) is captured by cyclones and a small part is conveyed with the gas to the bag filters that will treat gas with low dust content (e.g. 200 g/Nm3).
Vertical roller mills can use the total amount of hot gas coming form the kiln or only part of them, depending on the moisture of the raw material.
As for the horizontal mill, in this last case some hot gas is by-passed and, in general, this part doesn’t need to de cooled because already treated in the conditioning tower installed up stream.
Can be considered two type of circuits: two fans or three fans type.
From bag filter point of view:
- Three fans circuit= low dust load (e.g. 200 g/Nm3) and low operating negative pressure (-10 mbar)
- Two fans circuit= high dust load (e.g. 600 g/Nm3) and high operating negative pressure (- 60 mbar)