Industrial Emission Rate Calculator
Calculate mass emission rates based on flow and concentration.
About Emission Rate Calculations
Calculating the emission rate of pollutants is a fundamental aspect of environmental compliance, permitting, and impact assessment for industrial facilities. The Emission Rate Calculator helps environmental engineers and plant managers convert measured concentration data into mass flow rates.
The Formula
The basic physics behind the emission rate calculation involves multiplying the volumetric flow rate of the gas stream by the concentration of the pollutant within that stream.
E = Q × C
- E = Mass Emission Rate (Mass per unit time)
- Q = Volumetric Flow Rate (Volume per unit time)
- C = Pollutant Concentration (Mass per unit volume)
Unit Conversions Explained
In industrial stack testing, flow is often measured in Normal cubic meters per hour (Nm³/hr) and concentration in milligrams per Normal cubic meter (mg/Nm³). However, regulatory limits are often expressed in kilograms per hour (kg/hr) or Tonnes per year.
To convert (mg/Nm³ × Nm³/hr) into kg/hr:
- Multiply Flow (Nm³/hr) by Concentration (mg/Nm³) to get mg/hr.
- Divide by 1,000,000 (since there are 1,000,000 mg in 1 kg).
Calculation Example
Consider a boiler stack with the following parameters:
| Parameter | Value |
|---|---|
| Flow Rate (Q) | 25,000 Nm³/hr |
| NOx Concentration (C) | 150 mg/Nm³ |
| Operating Hours | 8,000 hours/year |
Step 1: Calculate Hourly Rate
25,000 × 150 = 3,750,000 mg/hr
3,750,000 / 1,000,000 = 3.75 kg/hr
Step 2: Calculate Annual Total
3.75 kg/hr × 8,000 hrs = 30,000 kg/year
30,000 / 1,000 = 30 Tonnes/year
Why Monitoring Matters
Accurate emission calculations are required for:
- Regulatory Compliance: Adhering to EPA or local environmental agency limits.
- Emission Fees: Many jurisdictions charge fees based on the total tonnage of pollutants emitted (e.g., NOx, SOx, Particulate Matter).
- Equipment Efficiency: Tracking emissions can indicate how efficiently a scrubber, baghouse, or precipitator is functioning.