Mystery Peak Before Propane

[chris3383]

I have a 6-port Daniel model 500 analyzer used for c6+ natural gas. Right before the propane peak there is normally a small ethane upset that can be adjusted with valve timing. Currently, we have an excessively large peak before propane and we cannot get it to change with valve timing, valve rebuild, valve replacement, and column replacement. Any help is appreciated!

[nipe]

a) columns separation;
b) timing table (valves+columns);
c) water (?)
Danalyzer 500 is a multi-valve analyzer, because it is need to see real gas flow diagram, what type of columns (capillar or packed, phases, d/l), carrier gas and operating mode. If you present these data , may be we can help you.