What are the advantages and disadvantages of each type?
In-situ Gas Analyzer
In-situ analyzers take advantage of the sample gas temperature contained within the stack. These analyzers tend to be lower in cost than an extractive system, due to lower manufacturing costs. In-situ analyzers typically require less upkeep as they don’t have filters or other sample conditioning components to maintain. Additionally, as you don’t need to remove the moisture from the sample being measured, you mitigate the risk of water-soluble compounds, like SOx, NH3, HCl, etc., from being removed, which can affect the “true measurement.”
However, there are also some important questions to consider before committing to an in-situ stack gas analyzer.
First and foremost is maintainability.