Thermal conductivity of gas by pulse injection techniques using specific thermal conductivity detector (TCD)

Abstract

This paper presents a procedure to determine the thermal conductivity of gases by pulse injection, using a thermal conductivity detector (TCD). The measurements are taken at 323K and atmospheric pressure with a 160 Ω tungsten filament sensor. Under well defined approximations the original nonlinear second order equation, which describes the sensors output, as a function of thermal conductivity and constant volume specific heat was transformed into a linear first order equation. According to this equation the time integrated, second order sensors electrical output signal, multiplied by the constant volume heat capacity is proportional to the constant volume heat capacity, divided by the thermal conductivity. The experimental results obtained with Ar, N2, O2, CH4, CO2, C 2H4, C3H6 and i-C4H 8 gases are in good agreement with the proposed theoretical model and the linearity correlation confirms the validity of the proposed method.