Water in Fuel Gas –Gas Analyser for Fully Automated Determination by Coulometric Karl Fischer Titration

Water is an unwanted contaminant in any kind of fuel gas as it lowers the calorific value and promotes corrosion. Hence, monitoring the water content is most critical, from the drying process of natural gas to any other point down the value chain. A proven solution to this challenge is the 875 KF Gas Analyzer, from Metrohm (Switzerland), combining precise sampling with the accuracy of coulometric Karl Fischer titration in a fully integrated, software controlled analyser.

There are many techniques available for the determination of low quantities of water. However, water in gas is a particular challenge: Residual scavenging solvents used in the purification process may interfere with competing methods such as dew point measurement, making coulometric Karl Fischer titration the only viable reference method to determine the true water content.

The 875 KF Gas Analyzer is controlled by tiamo, the leading control and database software for titration. The analyser module consists of a robust sampling system with a mass flow controller at its heart. Moreover, the system is equipped with an integral evaporator for liquefied gases, an inlet filter to separate out particles, and an oil filter. The titration vessel with indicator and generator electrode (with diaphragm), and an 851 Titrando coulometer are also included in the module. Safety is provided by the strict separation of the gas-carrying system and the electronic area.

Application Notes / Bulletins for the determination of the water content in the following matrices are available:

• AB-357        Determination of water in gases and liquefied gases with the 875 KF Gas Analyzer
• AN-K-055    Validation of the 875 KF Gas Analyzer with certified reference gas
• AN-K-058    Determination of water in butane using the 875 KF Gas Analyzer with and without extension for the heating oven
• AN-K-059    Determination of water in LPG and chlorethane
• AN-K-060    Determination of water in butadien with the 875 KF Gas Analyzer
• AN-K-061    Determination of water in propane with the 875 KF Gas Analyzer