instrumentation Case Studies

Online GC Vis-a-Vis Offline Gas Analysis

Introduction

By installing an Online GC, these disadvantages will be taken care. Here Analysis will be done every fixed Interval(eg. 4 minutes cycle) and the result will be directly communicated to Flow computer on a real time basis. Hence the accuracy of Flow measurement will be very high

GC Problems and Trouble shooting carried out at GCS Ramnad is described here.

Introduction

Now Normal Calibration done

But still total Un normalized concentration came very high

Consulted with Vendor After any change/repair/replacement etc it is mandatory to run 6-7 analysis with either calibration gas or sample gas(This is to purge the entire line properly.

Then Forced calibration to be done. And then normal calibration also to be done.

Now since existing Calibration gas exhausted, new calibration cylinder connected.(Calibration gas should not be used below 3 kg/cm2)

Changed component data table. And normal calib done. Excess RF Deviation alarm came.

Again RT Changed in Component data table and forced calibration done. After that normal calibration done. Now repeatability check carried out.

Repeatability OK.

Put in continuous analysis mode

07.04.2011

GC all parameters are normal Joint calibration Carried out and taken online.

Conclusions:

1. Any reduction in Sample flow rate is due to Chocking in either Sample probe/ sample line/ Genie filter/ Nupro filter Six Port Valve/Analyser Coloum(Low Probability)
2. In first case clean it/Purge it/ replace filter
3. In the second case rebuild six port valve(use aceton or fast evaporating cleaning Agent)
4. Bridge Balancing to be done.
5. Base line run to be done
6. Forced Calibration to be done followed by Normal calibration.

Please feel free to comment on this case

Regards.
C Vinod, DySE(E&T), GCS Ramnad 19.04.2011