Stack Emission Monitoring is the process of measuring pollutants released through industrial chimneys or DG sets to ensure CPCB compliance, protect public health, and improve process efficiency. It involves Continuous Emission Monitoring Systems (CEMS) for real-time data and Manual Stack Monitoring for periodic sampling of key parameters like Particulate Matter (PM10, PM2.5), SO₂, NOx, CO, VOCs, along with temperature, velocity, pressure, and flow rate. As per CPCB standards, industries must install CEMS, report data to SPCBs, and meet emission limits (e.g., PM ≤ 150 mg/Nm³, NOx ≤ 450 mg/Nm³, CO ≤ 100 mg/Nm³), while DG sets must follow stack height norms. Emission load is calculated using stack flow × concentration, and equipment like isokinetic samplers, flue gas analyzers, Pitot tubes, opacity monitors, and gas sensors are used. Alongside, industries must also meet effluent norms (BOD ≤ 30 mg/L, COD ≤ 250 mg/L). At Aaxis Nano, we offer advanced stack emission monitoring solutions including CEMS, analyzers, and samplers, ensuring accurate monitoring, regulatory compliance, and sustainability.
What is Stack Emission Monitoring?
Stack emission monitoring is the process of measuring and analyzing pollutants released into the atmosphere through industrial chimneys or stacks. It helps in assessing air pollution, ensuring compliance with environmental regulations, and optimizing industrial processes. Stack emissions generally include particulate matter, SO₂, NOx, CO, VOCs, and other hazardous gases, which must be kept within limits defined by the Central Pollution Control Board (CPCB).
What are Stack Emissions and Why are They Important?
Stack emissions are gases and particles released from industrial stacks or DG (diesel generator) sets. A stack is essentially a tall chimney used to disperse pollutants at a higher altitude, reducing their concentration at ground level. Monitoring these emissions is important because it ensures regulatory compliance, public health protection, and process efficiency.
How to Measure Stack Emissions?
Stack emission measurement can be done using two methods:
- Continuous Emission Monitoring Systems (CEMS): Real-time monitoring devices installed on stacks to measure gases and particulates continuously.
- Manual Stack Monitoring: Periodic sampling using devices like isokinetic samplers, gas analyzers, and dust monitors for pollutants such as SO₂, NOx, PM, CO, and VOCs.
What are the Requirements for Stack Emission Monitoring?
As per CPCB guidelines, industries must:
- Install CEMS for continuous monitoring.
- Report emission data to SPCBs (State Pollution Control Boards).
- Maintain records for audits and inspections.
- Meet emission norms for pollutants like SO₂, NOx, PM10, PM2.5, CO, and hydrocarbons.
CPCB Standards for Stack Emission Monitoring
- DG Set Stack Height Requirement: For a 1000 kVA DG set, the minimum stack height is 6.6 meters above the building height or ground level, as per CPCB norms.
- Emission Limits:
- SO₂ – Must be controlled based on fuel quality.
- Particulate Matter (PM) – ≤ 150 mg/Nm³ (for industries).
- NOx – ≤ 450 mg/Nm³ (depending on sector).
- CO – ≤ 100 mg/Nm³.
Parameters for Stack Emission Monitoring
The key parameters measured in stack monitoring include:
- Particulate Matter (PM10, PM2.5)
- Sulphur Dioxide (SO₂)
- Nitrogen Oxides (NOx)
- Carbon Monoxide (CO)
- Volatile Organic Compounds (VOCs)
- Temperature, Velocity, Pressure & Flow Rate
How to Calculate Stack Emissions?
Stack emissions are calculated using:
- Isokinetic Sampling: Measures dust and PM concentrations.
- Gas Analyzer Readings: Used for SO₂, NOx, CO, etc.
- Stack Flow Rate × Concentration Formula: Emission Load (kg/hr) = Stack Gas Flow (m³/hr) × Concentration of Pollutant (mg/Nm³) ÷ 1,000,000
Equipment Used in Stack Emission Monitoring
- CEMS (Continuous Emission Monitoring System)
- Isokinetic Dust Sampler
- Flue Gas Analyzer
- Pitot Tube for Flow Measurement
- Opacity Monitors
- Electrochemical & NDIR Gas Sensors
BOD and COD Limits in Effluent Discharge
While stack emissions cover air pollutants, industries also need to comply with effluent discharge standards. The CPCB norms specify:
- BOD (Biological Oxygen Demand): ≤ 30 mg/L
- COD (Chemical Oxygen Demand): ≤ 250 mg/L
Why Stack Emission Monitoring is Crucial
- Ensures compliance with CPCB and SPCB regulations.
- Protects public health from harmful pollutants.
- Provides real-time data for pollution control.
- Helps industries optimize fuel usage and reduce costs.
- Contributes to environmental protection and sustainability goals.
Stack Emission Monitoring Solutions by Aaxis Nano
At Aaxis Nano, we provide advanced stack emission monitoring systems, including CEMS, flue gas analyzers, and isokinetic samplers, tailored for industries like power plants, cement, steel, pharmaceuticals, refineries, and DG sets. Our solutions ensure accurate data, compliance with CPCB standards, and seamless integration with industrial automation systems.
