Patent ID: 6157455
Filing Date: 2000-12-05
Classification: G01N

Abstract:
A method of determining the calorific value of a natural gas optically and in real time by measuring the absorption of a light beam by the components of the gas, in which the gas is illuminated by a light beam of predetermined characteristics, the intensity of the light beam is measured after it has passed through the gas, and the calorific value of the natural gas is calculated from the optical absorption obtained on the basis of the measured intensity of the light beam after it has passed through the gas,wherein the gas is illuminated by means of a light beam defining three measurement bands defining different wavelength ranges, each having a bandwidth of 10 nm to 20 nm and situated in the near infrared, with wavelengths greater than or equal to 1.1 .mu.m and lower than or equal to 1.8 .mu.m, the measurement bands define wavelength ranges situated outside the absorption ranges of non-hydrocarbon components, and a reference band is also used defining a range of wavelengths having a bandwidth of 10 nm to 20 nm and situated in the near infrared outside the wavelength ranges of the measurement bands and of the absorption ranges of the gas.