Technical Terms – Perma Pure Knowledge Base

What do you mean by Sample Gas?

Gene Bohensky — Mon, 28 Jan 2019 13:05:26 +0000

In Perma Pure terminology, sample gas is the gas being either dried or humidified by the Nafion dryer or humidifier.

What is the Acid Dew Point?

Gene Bohensky — Tue, 01 Jan 2019 02:42:43 +0000

The acid dew point of a flue gas (i.e., a combustion product gas) is the temperature, at a given pressure, at which any gaseous acid such as SO2 in the flue / exhaust gas will start to condense into liquid acid. This phenomenon creates significant problems for gas sampling systems for CEMS, as the acids can wreak havoc on sampling lines, compressor coolers, eventually damaging the analyzers at the end of the sample line.

Deploying a Nafion based Sample Conditioning System on the stack can remove this potential problem by collecting the acid mists at the source with a filter and preventing formation downstream by removing more of the water in the vapor phase.

Perma Pure offers an accurate Acid Dew Point Calculator on our website.

PEM – Proton Exchange Membrane

Gene Bohensky — Fri, 28 Dec 2018 02:17:15 +0000

PEM – A Proton Exchange Membrane, is a semipermeable membrane generally made from ionomers and designed to conduct protons while acting as an electronic insulator and reactant barrier, e.g. to oxygen and hydrogen gas. It is common for Nafion to be used as a humidifier in PEM fuel cell applications.

NOx – Oxides of Nitrogen

Gene Bohensky — Fri, 28 Dec 2018 02:13:55 +0000

NOx are oxides of nitrogen, especially as atmospheric pollutants They are common pollutants measured in CEMS (Continuous Emissions Monitoring Systems).

SO2 (Sulfur Dioxide)

Gene Bohensky — Fri, 28 Dec 2018 02:11:02 +0000

SO2 or Sulfur Dioxide, is a gas that leads to formation of harmful compounds such as sulfuric acid, sulfurous acid, and sulfate particles, 99% of sulfur dioxide in the air comes from human sources. It is one of the most common pollutants measured in CEMS (Continuous Emissions Monitoring Systems).

Desiccant

Gene Bohensky — Fri, 28 Dec 2018 01:57:38 +0000

Desiccant a hygroscopic substance used as a drying agent, commonly used to dry gas samples prior to analysis

Ambient Air / Ambient Air Monitoring vs. Source Monitoring

Gene Bohensky — Fri, 28 Dec 2018 01:54:27 +0000

Ambient air is the that surrounds you, and ambient air monitoring sample points and various locations where people live and work. This is in contrast to Source monitoring, where the air or gases are monitored and measured at their source or point of creation, such as a smokestack.

Purge Gas Flow

Gene Bohensky — Wed, 07 Nov 2018 01:59:00 +0000

Purge Gas Flow – This is the dry gas used to remove the moisture form the sample gas. The purge gas flows opposite to the sample gas, from right to left, through the purge gas inlet to the purge gas exhaust and over the dryer tube(s) located within the shell of the dryer.

Sample Gas Flow

Gene Bohensky — Wed, 07 Nov 2018 01:58:05 +0000

Sample Gas Flow – This is the gas that is processed by the dryer to have the moisture removed. In the diagram, the sample gas flows from left to right through the center of the dryer from the Wet Sample/Feed Inlet to the Dry Gas Sample Outlet.

Nafion Retention

Gene Bohensky — Wed, 07 Nov 2018 01:55:54 +0000

Nafion Retention – The extent to which the components in the sample gas that one is trying to measure are kept intact. A list of chemicals and their approximate retention levels is kept on this website.