|
| |
|
 |
|
| |
 |
|
| |
|
|
| |
|
| |
|
|
| |
|
|
| |
| Initial
Diagnosis |
 TERI
carried out environmental measurements in
various foundry units in different locations
to assess the emission level of cupola stack
gases. During this exercise, the SPM (suspended
particulate matter) emissions without any
gas cleaning device were found to vary between
1300 and 3940 mg/Nm3. The measurements also
showed that the emissions from cupola were
much higher than the statutory limits. Therefore,
the installation of a pollution control device
was found to be necessary to comply with the
environmental regulations. TERI also analysed
the particle size distribution of cupola stack
gas in order to choose the right pollution
control system for foundries. |
| |
|
| |
| Pollution
control system |
Cupola stack gases contain a significant percentage
of fine particulates. Therefore, TERI used
a venturi scrubber to bring down the emissions
below the more stringent particulate emission
limit of 150 mg/Nm³.Some of the salient
features of the venturi scrubber are listed
below.
| - |
Variable venturi throat
to clean the gas by binding the particles
to water droplets |
 |
| - |
Optimum gas velocity at the throat,
liquid.:.gas ratio, and throat geometry
for maximum efficiency |
| - |
Dewatering cyclone after venturi to
retain water droplets in the gas stream |
| - |
Induced draft fan to ensure sufficient
pressure drop |
| - |
Stainless steel construction to prevent
corrosion |
| - |
Closed circuit recirculation to minimize
water requirement |
| - |
Lime dosing to maintain the pH of
the recirculating water |
| - |
Explosion doors and gas-tight construction
to prevent explosion. |
|
| |
|
| |
| Environmental
performance |
| |
|
TERI measured the SPM and sulphur dioxide
emissions of the outlet gas from the
pollution control device installed at
a foundry in Howrah. The SPM was found
to be about 50 mg/Nm3 and sulphur dioxide
was about 40 mg/Nm3. The results have
been validated by the monitoring conducted
independently by the pollution control
authorities. The capital investment
required for the pollution control device
is around Rs 15 00 000, which includes
the costs of chimney and other associated
structures.
|
 |
 |
|
| |
|
|
| |
|
|
|
|
|
|
| |
|
|
| |
|
|
|
