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What flue gases will you be monitoring and will it be continuous. If a toxic gas is detected will the plant automatically shut down. How frequently will the gas sensors be cleaned and tested?

The plant discharge stack will be equipped with the necessary continuous emissions monitoring systems to meet the relevant requirements of Natural Resources Wales/Environment Agency guidance and the Industrial Emissions Directive (IED).

CEMs will be installed to continuously monitor the following determinands in the stack gas:

  • particulate matter (i.e. total dust);
  • carbon monoxide;
  • oxides of nitrogen (NO and NO2 expressed as NO2);
  • ammonia;
  • sulphur dioxide;
  • volatile organic compounds (“VOCs”) (expressed as total organic carbon (“TOC”));
  • hydrogen chloride;
  • oxygen, wet (and dry if necessary);
  • moisture;
  • temperature;
  • pressure; and
  • velocity and flow.

Periodic measurement of hydrogen fluoride will be carried out.

Duplicate CEMs systems will be installed.  This will ensure that, in the event of a failure in the duty system, continuous monitoring of emissions to air will continue using the stand-by system.

All CEM systems that will be installed at the plant to monitor emissions to air from the discharge stack will be certified under the EA’s MCERTS scheme for the appropriate measurement ranges and will meet the requirements of the quality assurance standard BS EN 14181:2004 Stationary source emissions - Quality assurance of automated measuring systems.

The CEM systems will be provided with an uninterruptable power supply (“UPS”) so that they will be able to continue monitoring the emissions to air from the discharge stack in the event of a power interruption to the plant.

The CEM systems will be supported by an integral software package that will be configured so that only valid data is considered for reporting purposes; that produced during start-up and shutdown will be excluded.  The software will automatically correct the raw data so that it is reported to the reference conditions - 273K, 101.3kPa, 11% oxygen, dry - and averaging periods in accordance with the relevant reporting requirements.  This will ensure that the CEMs data can be directly compared with the Emission Limit Values (“ELVs”) for emissions to air detailed in Part 3 of Annex VI of the IED.

QAL2 calibration and validation procedures on the CEM systems are undertaken when the CEM is installed, if an internal evaluation dictates the need for a QAL 2 test, if an annual surveillance test dictates a need, after a failure, if there is a change in fuel, if there is a significant change in process, where the CEM exceeds the limits for operating outside valid calibration ranges or every five years.

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