| 摘要 |
PURPOSE:To eliminate the error in a measuring value due to hydrocarbon in a gas, by preliminarily treating a sample gas supplied to a gas analyzing apparatus due to absorption photometry with activated carbon under heating to remove hydrocarbon by adsorption. CONSTITUTION:A gas analyzing apparatus is mainly constituted from an activated carbon packing tower 3 provided to a sample gas flowline 2 to an NO2 densitometer 1 such as an ultraviolet ray absorbing analytic apparatus, an electric heater 4 provided to the periphery of said activated carbon packing tower 3, a thermometer 5 provided in the activated carbon layer in the packing tower 3, a nitrogen gas flowline 6 for diluting a sample gas entering said packing tower 3, a nitrogen gas supply pump 7, a flow meter 8 and a liquid seal 9. The sample gas from the sample gas flowline 2 is diluted with an inflow nitrogen gas from the nitrogen gas flowline 6 in a predetermined ratio while the diluted sample gas is passed through the packing layer of the activated carbon packing tower 3 where hydrocarbon in the sample gas is removed by adsorption and enters the NOx densitometer 1 to measure an accurate NOx value as the gas free from a harmful gas such as hydrocarbon. |
