The COSA/Xentaur Continuous Hydrogen Analyzer (CHA), used in countless UOP Schedule A applications for many years, is built under a license to a patented UOP design. It provides petroleum refiners, petrochemical producers, and electric power generators a means to continuously and accurately monitor hydrogen concentration in gaseous streams. Continuous Hydrogen Analyzer Utilizing a unique, patented electrochemical sensor, the CHA outputs a continuous signal corresponding directly to the hydrogen concentration. Used in conjunction with real-time controls, alarms, and shut-off mechanisms, the CHA responds immediately to changing hydrogen levels for improved operations and safety. Unlike thermal conductivity-based hydrogen analyzers, the CHA measures hydrogen directly and specifically. Built around a polymer membrane with proton-conducting properties, the CHA sensor detects hydrogen concentrations ranging from 400 ppm to 100% by volume in discrete ranges with 1% accuracy or better (dependent upon sample concentration and reference gas composition). Installation, Calibration, and Maintenance Depending on the application, a sample gas stream is typically diverted to the CHA from the makeup gas line, reactor outlet, stabilizer offgas, or power generator casing. As it exits the analyzer, the sample stream can either be vented or returned to the process. Installation is easily completed by plant personnel. Upon installation, the analyzer is calibrated for measuring hydrogen concentration within a discrete, specified range. Using two calibration gases of known concentration and a specific, continuous flowing reference gas, a simple two-point calibration is completed in less than 30 minutes. Thereafter, calibration checks are recommended every three months, or when the reference gas cylinder is changed. With no moving parts and extremely high stability, the CHA requires very little maintenance. Commercial uptime is reported to exceed 99%.