chapter - 1 introduction - Meghalaya State Pollution Control Board

Hills Cement Co. Limited.
Bag filters will be installed at all material transfer points and material
conveying systems - air slides, bucket elevators etc. Belt conveyor swill be
used for stacking the -80 mm size limestone to reduce the falling height and
hence to reduce dust generation. Gypsum and coal will be received in wet
condition, hence; will not require any specific control measures. All raw
material storages and conveyors will be covered. In order to control air
pollution systems like fly ash system with ESPs, dust suppression systems
with water spraying and ventilation systems have been envisaged.
The main stacks emitting most of the SPM emission are given in Table 5.1
along with the proposed air pollution control equipment.
TABLE 5.1
MAIN STACKS AND SPM CONTROL EQUIPMENT
Sl.
Stack name
Height
Dia
SPM control
Max. SPM
No.
(m)
(m)
equipment
emission in
mg/Nm 3
1. Clinker cooler 30.0 1.80 ESP 55.0
2. Primary crusher 21.0 1.19 Bag house 50.0
3. Secondary crusher 13.0 1.00 Bag house 60.0
4. RABH (kiln & raw mill) 47.5 3.00 Bag house 65.0
5. Coal mill 37.0 1.18 Bag house 50.0
6. Cement mill 20.5 1.20 Bag house 52.0
7. Packing plant 10.0 0.60 Bag house 45.0
8. Power plant 80.0 2.50 ESP 75.0
Pollution control equipment for outlet of raw mill & kiln has got two options,
namely: ESP and bag filter, both are extensively used by large cement plants.
ESP has got the advantage of low-pressure loss, high temperature
adaptability and low recurring cost. However, tripping due to system failures
rather common & frequent, requiring high degree of maintenance. Bag filters
are also available for high temperature (up to 260°C on continuous basis and
280°C for a shorter period). Pressure loss is high and maintenance cost is
high as it requires regular replacement of bags. If the system fails due to
process disturbance and temperature increases, fresh air is automatically
drawn in, to maintain the temperature of gases within permissible
Pollution Control Consultants (India) Pvt. Ltd. 92