ACCURATE CELL PRESSURE REGULATION AND VENT RECOVERY SYSTEM FOR CONTINUOUS ANALYZERS

摘要

Sample delivery and disposal present several challenges to the Analyzer Engineer. In order for anrnanalyzer to remain calibrated, it is imperative that the sample pressure be delivered at the precisernpressure at which the analyzer was calibrated. Additionally, by-pass flow which is necessary torndecrease sample transport time to the analyzer, and effluent from the analyzer must be vented via anrneconomic, safe and environmentally compliant method. As Clean Air Act laws are imposed, many usersrnfind the Flare Header to be the disposal method of choice. Therefore, elements of a pressure regulationrnand vent recovery system must have the capability to maintain low-pressure levels with a high degree ofrnsensitivity and stability to minimize fluctuations in sample pressure presented to the analyzer cell. Thisrndiscussion will present a system design that provides better than 0.1 psi analyzer cell pressure stability,rnregardless of supply pressure. Additionally, the system incorporates a volumetric flow controller tornisolate downstream pressure and flow fluctuation from flare header dynamics. This discussion willrnpresent data from various lab test scenarios as well as real-world on-line installations.