Stack Emission Monitoring Procedure
Stack Emission monitoring procedure includes tasks of Measurement, testing, sampling and analysis. Onsite determination of physical parameters of flue gases such as temperature, flow and pressure also involved in Stack emission monitoring.
Air Quality is a major environmental responsibility for all manufacturing industries. Those industries can use air quality monitoring or stack monitoring to measure the degree of pollutants or contaminants present in the current exhaust air and take the required steps to reduce them.
All industries must have a sampling port built into their stack and a permanent sampling platform to ease the Stack Emission Monitoring Procedure for environmental consultants who perform monitoring of stack emission.
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Stack Emission Monitoring Procedure
Selection of Sampling Site in Stack Emission Monitoring Procedure
The objective of sampling in the Stack Emission Monitoring Procedure is to determine the accurate degree of pollutants present in the air emitted from the stack. Laminar flow should be present in the stack to get accurate readings.
To select a representative sample sampling point should be at least eight stack diameter downstream and two-stack diameter upstream from any joint, bend, expansion and contraction.
As per new Notifications, all stacks must have a sampling post and sampling platform. The location of traverse points will be decided by the pollution control board.
After previous criteria met, to determine the minimum traverse points required the first diameter of the stack is to be calculated in the case of a circular stack. Also, it should be far 3cm from the stack wall.
Stack Emission Monitoring Procedure Download files (PPT and PDF)
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Molecular Weight Determination
Molecular weight can be found by drawing a known amount of gas into a gas chromatograph or Orsat apparatus. Moisture should be found. Molecular weight can be calculated by knowing gas components.
The average molecular weight can be determined by using the below-mentioned formula:
M = ∑ (i=1)^n (xi Mi)
X is the mole fraction and Mi is mole weight of each constituent in a mixture of a several constituent.
Once the Pitot tube is connected Dynamic and static pressure is found using a manometer. Also, the Temperature inside the duct is measured. The velocity of gas and amount of air can be found using the formula
Moisture can be determined by dry and wet bulb temperature and the referring to the psychometric chart. Also, the condenser method works well for almost all gas streams and comparatively easy to perform.
Condenser Method to determine Moisture in a Gas Dtream
In this process sample of the stack is extracted through a filter to remove particulate matter than through the condenser, collecting the condensate formed in the process and then it is measured.
Wet/Dry Method to Determine Moisture in Gas Stream
The equilibrium temperature attained by water which is vaporizing into a gas of constant composition and the constant dry bulb is called wet-bulb temperature. The amount of depression of wet bulb temperature below the dry bulb is the saturation degree of humidity of the gas. Hence, the moisture content of gas can be determined by using the wet and dry bulb method.
After the sample has cooled, brush down the dust on side of the nozzle into a thimble and replace it in a labelled container.
This blog is written by Perfect Pollucon Services. They offer Environmental services in India including Consultancy and Monitoring Services.