In any combustion process, it is necessary to monitor the inlet flow rates of fuel and air to the burner. While these flow rates provide baseline parameters to set a flame, they do not provide feedback to reveal or alert any potential concerns with the combustion reaction, such as incomplete combustion from imperfect mixing in the burner or safety risks such as fuel leaks or loss of flame. Flue gas analysis offers one approach to monitor the process and provide feedback. It is especially important to consider when firing both hydrocarbon-based and high hydrogen fuels.
Hot-wet continuous emission monitoring (CEM) measurement means analyzing the stack gas sample on an as-is basis, which ensures that the integrity of the sample, from extraction through analysis, is maintained. Keeping a good heat integrity in hot-wet measurement is very important to prevent the condensation of acid mist or water vapor.
If you work in the natural gas industry or are an industrial user of natural gas, water dewpoint is not only a quality measurement but also a big concern. Water condensate presents serious challenges and issues for your process. It is highly corrosive and will form hydrates, which are ice-like solid molecules that can block the flow of gas in pipelines. In cold weather, it will also freeze reducing the pipe pressure.
If you’re a user of moisture analyzers, you’ve probably experienced challenges in performing a quick, accurate measurement using a portable instrument. Portable moisture analyzers are typically used to verify the moisture reading of a fixed-installation instrument or to conduct spot-sampling measurements at remote sites which lack a permanently installed device. In my experience performing portable measurements, I’ve seen several common obstacles a user may encounter:
Measuring Water Vapor in Hydrocarbon Streams
Extracted from a variety of different sources, natural gas is composed of many different hydrocarbons and includes other, less desirable, impurities. These impurities – such as water, carbon dioxide, and hydrogen sulfide – are removed due to adverse effects, including:
- Reducing the heating value of the natural gas
- Damaging piping and other mechanical hardware due to freezing or corrosion
- Meeting tariff limits associated with transaction contracts