CONSIDERATIONS FOR APPROPRIATE FLARE SAMPLING AND ANALYSIS

摘要

Extracting representative material from a Flare Stack at pressures of only a few inches of water, temperatures of 100 to 500 Deg. F, and water concentration of 5 to 30 % requires attention to details. Pumping the sample creates a problem with condensing water due to the increase in pressure and removing the water may lose target analytes. A vacuum eductor lowers the pressure and aids in keeping the moisture in the vapor state. The eductor is blocked prior to sample injection and the transfer line is allowed to equilibrate to stack pressure. A discrete sample is injected quickly and the eductor is returned to service. This procedure is believed to keep the transfer line clean and provides a fresh representative sample to the analyzer. The transfer line is heat traced to reduce condensation and loss of analytes. A Thermal Conductivity Detector [TCD] and a Flame Ionization Detector [FID] are needed to make a total component analysis. Utilizing a simple British Thermal Units [BTU] detector may provide periodic heat content information and reduce the number of measured components. Data can be collected with a conventional Laptop PC, signal interface, and chromatographic software. A pressure sensor between the sample loop and the block valve can be used to monitor stack pressure and eductor performance. Measurement of only the major components may also simplify determination of the target analytes and packaging of a field mounted system.