Gas System Flow Rate Measurement System

Perhaps the most fundamental parameter to be measured in gas handling systems is the flow rate. Determining the best method for measuring flow rate can be difficult. For low-pressure, non-toxic gas streams the pilot-tube traverse is typically the method of choice. It has been well researched and is sanctioned by the U.S. Environmental Protection Agency ( for most air pollution work.

Air Pollution Control: General

September 11, 2019

Particulate Matter Isokinetic Sampling

Much time and money are spent by field investigators trying to ensure that particulate sampling is conducted isokinetically; but with today’s tighter emission standards and better control equipment it might be worthwhile to consider just how important isokinetic sampling is before conducting your next stack test.

Air Pollution Control: General

September 6, 2019

Wet ESP Corona Quenching Effect

Operators of wet electrostatic precipitators (wet ESPs) often notice that the secondary current and voltage readings tend to rise and fall with the particulate loading. This phenomenon is known as space charge corona quenching, and it can have a serious impact on the performance of a wet ESP.

Wet Electrostatic Precipitator

Wet ESP Limits of Deutsch Equation

The equation, by nature, predicts that no precipitator can be 100% efficient. This is true in real world applications even if rapping and/or re-entrainment losses are eliminated.

What many people do not realize is that the Deutsch Equation is based on the assumption of turbulent flow. This assumption precludes the possibility of 100% capture. If a precipitator operates on a laminar gas stream, however, then 100% efficiency is both theoretically and practically possible. A good example of this possibility is household air cleaning precipitators. These precipitators have very narrow gas passages that allow them to approach a laminar flow situation. These devices typically demonstrate performance, in terms of efficiency per unit of collecting area, that is significantly greater than the performance of even the best turbulent flow devices.

Wet Electrostatic Precipitator

September 5, 2019

Acid Gas Sampling Issues

Current U.S. Environmental Protection Agency ( test methods for particulate concentration in stack gases can yield inaccurate results when hydrogen chloride (HCl) is present and the gas stream is at or near the saturation point…

Air Pollution Control: General

Particulate Matter

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