Method and apparatus for determining the calorific value of a natural gas optically and in real time

摘要

Natural gas whose calorific value is to be determined is illuminated with a light beam that is applied by a measurement head and that defines three measurement bands with different wavelength ranges each having a bandwidth of 10 nm to 20 nm and all situated in the near infrared. The intensity of each light beam is measured after it has passed through the gas, and the calorific value of the natural gas is computed in situ and in real time on the basis of the optical absorption values obtained by measuring the intensities of the light beam after it has passed through the gas.