Maintain temperatures in gas sample lines to enhance measurement accuracy

R. Rieken, Swagelok Co., Solon, Ohio Within a gas sampling system, numerous variables can affect the accuracy of analyzer measurements. However, the most common culprit of incorrect measurements is the improper control of sample line temperatures. When a hot gas sample is pulled from a process line into a sampling system that is unheated or at a too-low temperature, the gas will cool rapidly. As it does, it will naturally condense, creating a sample that is part gas and part liquid. The concentration of the remaining gas in the sample will therefore no longer be representative of the process gas, and the analyzer measurement will not provide a true reading of process conditions. To prevent