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
The removal of these impurities is known to most but, what cannot be forgotten, is that even hydrocarbons heavier than methane are often removed and repurposed. These hydrocarbons have an intrinsic value and include ethane, propane, and butane, referred to as natural gas liquids (NGLs). Depending on the concentration of these hydrocarbons, the heating value of consumer and commercially utilized natural gas may be impacted. Alternatively, these hydrocarbons can be sold as individual components as fuel for different types of heaters, or as valuable feedstocks in the production of plastics. The hydrocarbons can be separated out of the raw gas stream in a process known as fractionation.
Like the natural gas (typically 90%+ methane) that is transported around the world for use in homes, businesses, and industrial facilities, ethane, propane, and butane also have limitations on moisture content. In order to ensure contract terms are met, natural gas processing and fractionation facilities routinely measure the moisture content before transferring the hydrocarbons to buyers.
The 5100P transportable TDLAS moisture analyzer is designed to measure moisture at very low parts per million (ppm) levels in these differing hydrocarbon streams. Specific configuration and testing ensure accurate measurement, whether the background gas is 95%+ methane, ethane, propane, or butane. As an easily transportable TDLAS-based analyzer, the 5100P can be used as a sole source to confirm product purity or be used to validate that accurate measurements are being made by fixed installation analyzers located in one, or several plants.