Question

For assessing the compliance with the emissions standards of incineration plants, a correction needs to be applied to the measured concentrations of air pollutants. The emission standard (based on 11\% Oxygen) for HCl is 50 mg/Nm$^3$ and the measured concentrations of HCl and Oxygen in flue gas are 42 mg/Nm$^3$ and 13\%, respectively. Assuming 21\% Oxygen in air, the CORRECT statement is:

• A. No compliance, as the corrected HCl emission is greater than the emission standard.
• B. Compliance is there, as the corrected HCl emission is lesser than the emission standard.
• C. Compliance is there, as there is no need to apply the correction since Oxygen is greater than 11\% and HCl emission is lesser than the emission standard.
• D. No compliance, as the Oxygen is greater than 11\% in the flue gas.

Hint:

When adjusting pollutant concentrations for compliance based on oxygen levels, always ensure calculations reflect variations from standard atmospheric conditions to avoid non-compliance.

Answer 1

The Correct Option is A

Step 1: Calculate the corrected HCl concentration based on the oxygen content. The correction formula based on the oxygen concentration is given by: \[ C_{\text{corr}} = C_{\text{measured}} \left(\frac{21 - \text{Oxygen standard}}{21 - \text{Oxygen measured}}\right). \] Substituting the given values (\( C_{\text{measured}} = 42 \) mg/Nm$^3$, Oxygen standard = 11\%, Oxygen measured = 13\%): \[ C_{\text{corr}} = 42 \left(\frac{21 - 11}{21 - 13}\right) = 42 \left(\frac{10}{8}\right) = 52.5 \text{ mg/Nm}^3. \] Step 2: Compare the corrected HCl concentration to the emission standard. \[ C_{\text{corr}} = 52.5 \text{ mg/Nm}^3 \text{ is greater than the standard of } 50 \text{ mg/Nm}^3. \] Therefore, the emissions exceed the standard.