30-01-2013, 12:05 PM
Stack Monitoring – Material and Methodology for Isokinetic Sampling
[attachment=48865]
SOURCE EMISSION MONITORING
This section deals with the method of source emission monitoring. It also gives the
minimum requirement of a stack monitoring equipment.
Properly constructed Type S pitot tube shown in: a) Top view; face opening planes
parallel to longitudinal axis; b) side view; both legs of equal length and central lines
coincident, when viewed from both sides. Baselines coefficient values of 0.84 may be
assigned to pitot tubes constructed this way.
Method of Testing
Molecular weight determination
• Dry and wet molecular weights
Equation 1 is used to calculate the dry molecular weight of flue gas. This
equation may be modified with terms if other gaseous constituents that will
influence the molecular weight if present. Equation 2 is used to calculate the
molecular weight of the sample is used to calculate the molecular weight of the
gas on a wet basis.
Wet / dry bulb method
The equilibrium temperature attained by water, which is vapourizing adiabatically
into gas of composition and constant dry bulb or actual temperature, is termed as
wet bulb temperature. The amount of depression of the wet bulb temperature
below the dry bulb temperature is a function of the degree of saturation of the
humidity of the gas. Therefore, the moisture content of the gas can be
determined from the wet and dry bulb temperature.
• Calculations – the moisture content may be determined from the test data using a
psychrometric chart. The percentage water vapour by volume is found directly.
Inputs are the dry bulb temperature and wet bulb temperature.
[attachment=48865]
SOURCE EMISSION MONITORING
This section deals with the method of source emission monitoring. It also gives the
minimum requirement of a stack monitoring equipment.
Properly constructed Type S pitot tube shown in: a) Top view; face opening planes
parallel to longitudinal axis; b) side view; both legs of equal length and central lines
coincident, when viewed from both sides. Baselines coefficient values of 0.84 may be
assigned to pitot tubes constructed this way.
Method of Testing
Molecular weight determination
• Dry and wet molecular weights
Equation 1 is used to calculate the dry molecular weight of flue gas. This
equation may be modified with terms if other gaseous constituents that will
influence the molecular weight if present. Equation 2 is used to calculate the
molecular weight of the sample is used to calculate the molecular weight of the
gas on a wet basis.
Wet / dry bulb method
The equilibrium temperature attained by water, which is vapourizing adiabatically
into gas of composition and constant dry bulb or actual temperature, is termed as
wet bulb temperature. The amount of depression of the wet bulb temperature
below the dry bulb temperature is a function of the degree of saturation of the
humidity of the gas. Therefore, the moisture content of the gas can be
determined from the wet and dry bulb temperature.
• Calculations – the moisture content may be determined from the test data using a
psychrometric chart. The percentage water vapour by volume is found directly.
Inputs are the dry bulb temperature and wet bulb temperature.