Challenges
lNetherlands NOx Emissions Credit Trading
lContinuous NOx Emissions Monitoring if > 100 MWth
lCEMS (hardware) or PEMS (software)
lPerformance Requirements
lEn-14181: QA standards for continuous emissions monitoring at stationary sources
–NOx accuracy ± 20%
–Availability > 97%
lGas Turbine
l160 MWth, 19 burners, dry low NOx
lExtremely Short Project Schedule
lUrgently replace poor performing monitoring system
Pernis, The Netherlands
NOx profile relative to burners in operation
•The Shell Refinery in Pernis, The Netherlands urgently needed a continuous NOx emissions monitoring system to meet their obligations to the Netherlands’ NOx Emissions Credit Trading program. Their current monitoring system failed to meet the performance requirements of accuracy and availability as defined by the regulatory agency’s  quality assurance standards.
•The gas turbine, to be monitored, is an ABB 160 thermal mega watt, 19 burners, dry low NOx emissions unit. The monitoring system must accurately predict NOx emissions (NOx profile) relative to the number of burners in operation.
•Due to the poor performing existing monitoring system, Shell urgently needed the newer system installed and certified. In fact, Shell had developed (internally) their own PEMS that took into consideration, approx. 15 operating inputs and extrapolated from this, the NOx emissions. This simple approach was no match for the sophisticated and complex dry low NOx gas turbine with its capacity to use up to 19 burners. The internally developed PEMS’ accuracy exceeded the performance requirements of the Netherlands authorities. After a lengthy period of negotiations, the agency gave Shell a short 7 weeks to replace their poor performing monitoring system and get back into compliance.