... Separation for many valves and columns, TCD system analysis H2, O2, CH4, CO, C2H6, CO2, H2S, C2H4, C3H8, C3H6, ... ON, C6+ was flow back to TCD, examined. Components O2, N2, CH4, CO, CO2 and C2 flow out ... H2S, C3 and above will be brought into detector TCD by gas carrier 2 and be detected, switch the valve ... Switch the valve V3 from ON to OFF, components O2, N2, CH4 and CO will be detected. Analysis ...