Patent ID: 7091043
Filing Date: 2006-08-15
Classification: C01C,G01N,Y02A,Y10T

Abstract:
1. A method for measuring a water concentration in liquefied ammonia having a water concentration of no more than 10 ppm, comprising: introducing a gaseous phase moiety of liquefied ammonia, said liquefied ammonia having a water concentration of 10 ppm or less, as a reference gas into a multi-reflection long optical path cell, measuring infrared (IR) spectrum of the reference gas as a background of an IR spectrometer, introducing a gas obtained by vaporizing liquefied ammonia as a sample at a constant flow rate into the cell, measuring infrared (IR) spectrum of the sample employing the background of the spectrometer, measuring absorption intensity in the IR spectrum of the sample at an infrared wave number at which water absorbs IR and at which infrared absorptions of water and ammonia do not overlap, and determining the water concentration based on the measured absorption intensity from a water concentration calibration curve prepared in advance.