Stack Testing Case Study:
Investigating the Cause of Failure in a Compliance Test
Stack emissions from a gas-fired turbine which historically have very low particulate matter counts unexpectedly failed the regular particulate compliance test. Once out of compliance, companies must investigate the issue. MVA Scientific Consultants was asked to examine the particulate. The particulate was originally thought to be combustion-related, since it was from a gas-fired turbine. However, examination of the materials on the Method 5 filters by scanning electron microscopy revealed the particulate was consistent with dirt.
This information proved to be useful. With some investigation, the client found that the duct work and stack had been built and then left sitting in the desert for a year. The construction company had not cleaned the hot gas path and just installed the back end of the unit after setting the turbine. When the back end of the duct was examined, large quantities of sand and dirt were scattered everywhere. A cleanup effort was launched and the facility finally passed the stack compliance test.