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.
Gas conditioning towers
The Evaporative Conditioning towers (ECT) are installed before electrostatic precipitators or bag filters.
Their task is to cool down hot gas or hot air flows in order to reach the right operating temperature for a bag filter or change the gas electrical caracteristics to improove electrostatic precipitators efficiency. In this last case, beside the cooling down, the scope is also to increase the water content in the gas to further reduce resistivity.
Gas conditioning towers controls
The GCT operation principle is based on the use of the gas sensible heat for evaporating water.
Usually the water injection is controlled according to the outlet temperature set point.
A different type of control is possible according to the entalpy of the gas stream at GCT inlet. The accuracy depends on the flow measure reliability that is affected by the dust content.
This type of control is normally used only to anticipate water control specially in transient operation (e.g. for cement, during switching from direct to compound operation in kiln-raw mill lines).