Trailer Mounted Analysers Allow Flexible Monitoring of Gas Turbines

National Grid is set to potentially make substantial cost savings on the monitoring of gas turbine emissions by using a new trailer mounted emission analysing system designed and built by ABB (UK).

The trailer, based on the ABB Advance Optima AO2000 Series, will measure the emissions of gas turbine engines used in the compression of gas for transport on the national transmission system. The data on turbine performance will be used to help National Grid to take a more preventive approach to maintenance.                        

National Grid has had its own in-house test teams for 20 years. These teams have ensured that installed Predictive Emission Monitoring Systems (PEMS) are properly calibrated and conform to National Grid‘s license agreement with the Environment Agency. With its current mobile calibration systems reaching their end of life, National Grid issued a tender for a solution to replace them, which was won by ABB in January 2015. National Grid was reassured of the quality and reliability of ABB analysers by EON, which has used them for a number of years.

“So far the mobile emissions laboratory has been van mounted,” says Matt Williams, National Grid’s Environmental Officer, responsible for scheduling emissions testing for gas turbines. “While we wanted a replacement for the existing van based system, we also wanted a solution that would give us more flexibility, in the form of a portable unit that can be left on site. A lot of gas turbines are switched on and off at unpredictable times to account for demand so we needed a unit that could undertake remote operation for a longer period of time.

“Much emissions testing is also performed on gas turbines following a shutdown. Sometimes we do not know exactly when a test will be required, so having a portable unit available means we can pre-position the trailer at the site, ready to conduct a test at short notice. This also avoids the time and costs of sending test engineers to the site.”

National Grid contacted three possible suppliers, two of whom expressed interest in providing a solution. ”The ABB quote met all of the specifications and I had real confidence in that they could deliver what they promised.“

The solution is based on the ABB Advance Optima AO2000, a modular system which consists of one master analyser with a power supply and housing with display and control unit, also known as the “central unit”.

Based on a common control system, common communications and a common system housing, up to four slave analyser modules can be arranged in various ways to form single or multiple analyser systems. Advance Optima offers analyzer modules using various measurement principles, enabling a single system to handle multiple parameters.                  

The solution for National Grid will consist of a Uras26 Infrared analyser module, MAGNOS oxygen analyser modules and a Multi FID Flame Ionisation Detector. Each analyser module consists of the sensor and its own processor.

The system will allow National Grid engineers to measure emissions at the gas compressor stations remotely,  using a 3G network to access analyser data and diagnostics. National Grid will also be able to make use of an Envirosoft reporting package to create reports on the performance of the gas turbines.

The trailer will initially be used as part of a research program in partnership with a gas turbine OEM and commissioned into service during 2016. A van mounted system is also due later this year.